Photoconversion efficiency of quantum-well solar cells for the optimum doping level of a base

written by chinedu j. ekerue Photoconversion efficiency of quantum-well solar cells for the optimum doping level of a base Abstract. Analytical expressions for the maximum obtainable photoconversion efficiency of quantum-well solar cells (QWSCs) under AM0 conditions are given. The modeling of the photoconversion efficiency of QWSCs under AM1.5 conditions using the SimWindows program is fulfilled. It is shown that the photoconversion efficiency of QWSCs with the A3B5 p-i-n structure is rather low because of a low photovoltage value. To improve this situation, the base region should be doped heavily enough. Light concentration makes it possible to realize high photoconversion efficiencies for A3B5 quantum-well p-i-n structures with a low background level of the base region doping. Their values are comparable to the photoconversion efficiencies for solar cells (SCs) with rather high base region doping levels. 1. Introduction The question of the availability of quantum-well solar cells (QWSCs) is highly attended last years. Many researches cover features of QWSCs, and there are the special sections on such questions at European and world solar energy conferences for last nine years. By efforts of scientists headed by Prof. K.W.J. Barnham at the Imperial College in London, the laboratory patterns of A3B5 QWSCs with high efficiency comparable with the record value in conventional SCs have been obtained [1–3]. However, up to now, all efforts have been concerned with the analysis and the fabrication of QWSCs with p-i-n structures and a low doping of the base region. There was no comparative analysis of the photoconversion efficiency for QWSCs and conventional SCs. In this work, we present the results of a theoretical analysis of the efficiency of photoconversion at the optimum doping of the base region. The present paper consists of three sections. Analytical expressions for the maximum obtainable photoconversion efficiency of QWSCs at AM0 conditions are obtained in the first section. The maximum obtainable photoconversion efficiency of QWSCs as a function of the quantum well bandgap for GaAs, AlGaAs, and Si as the barrier material is calculated using these expressions. The calculations have been carried out for both concentrated and non-concentrated illuminations. The modeling of the photoconversion efficiency of QWSCs at a non-concentrated illumination under AM1.5 conditions is fulfilled using the SimWindows program [4, 5] in the second section. GaAs is considered as the barrier material with InGaAs quantum wells. It is shown that the photoconversion efficiency of QWSCs can considerably exceed the conventional efficiency of SCs under two conditions: 1) the quantum well carrier lifetime exceeds the barrier carrier lifetime; 2) the doping level of the base region does not exceed 1017 cm−3. However, the maximum photoconversion efficiency is achieved in conventional SCs with doping levels higher than 1017 cm−3. In the third section, it is shown that concentrated illumination allows one to achieve the high photoconversion efficiency in quantum well p-i-n structures with the low base region doping. This efficiency is comparable with the efficiency of SCs with highly doped base region. Then we present a detailed description of the obtained results. CHAPTER TWO photoconversion is a photoactivatable fluorescent protein naturally originated from a stony coral, Trachyphyllia geoffroyi. It was named Kaede, meaning "maple leaf" in Japanese. With the irradiation of ultraviolet light (350–400 nm), Kaede undergoes irreversible photoconversion from green fluorescence to red fluorescence. It is a homotetrameric protein with the size of 116 kDa. The tetrameric structure was deduced as its primary structure is only 28 kDa. This tetramerization possibly makes Kaede have a low tendency to form aggregates when fused to other proteins. The property of photoconverted fluorescence Kaede protein was serendipitously discovered and first reported by Ando et al. in Proceedings of the United States National Academy of Sciences.[1] An aliquot of Kaede protein was discovered to emit red fluorescence after being left on the bench and exposed to sunlight. Subsequent verification revealed that Kaede, which is originally green fluorescent, after exposure to UV light is photoconverted, becoming red fluorescent. It was then named Kaede. Properties The property of photoconversion in Kaede is contributed by the tripeptide, His62-Tyr63-Gly64, that acts as a green chromophore that can be converted to red.[2] Once Kaede is synthesized, a chromophore, 4-(p-hydroxybenzylidene)-5-imidazolinone, derived from the tripeptide mediates green fluorescence in Kaede. When exposed to UV, Kaede protein undergoes un conventional cleavage between the amide nitrogen and the α carbon (Cα) at His62 via a formal β-elimination reaction. Followed by the formation of a double bond between His62-Cα and –Cβ, the π-conjugation is extended to the imidazole ring of His62. A new chromophore, 2-[(1E)-2-(5-imidazolyl)ethenyl]-4-(p-hydroxybenzylidene)-5-imidazolinone, is formed with the red-emitting property. The cleavage of the tripeptide was analysed by SDS-PAGE analysis. Unconverted green Kaede shows one band at 28 kDa, where two bands at 18 kDa and 10 kDa are observed for converted red Kaede, indicating that the cleavage is crucial for the photoconversion. A shifting of the absorption and emission spectrum in Kaede is caused by the cleavage of the tripeptide. Before the photoconversion, Kaede displays a major absorption wavelength maximum at 508 nm, accompanied with a slight shoulder at 475 nm. When it is excited at 480 nm, green fluorescence is emitted with a peak of 518 nm. When Kaede is irradiated with UV or violet light, the major absorption peak shifts to 572 nm. When excited at 540 nm, Kaede showed an emission maximum at 582 nm with a shoulder at 627 nm and the 518-nm peak. Red fluorescence is emitted after this photoconversion. The photoconversion in Kaede is irreversible. Exposure in dark or illumination at 570 nm cannot restore its original green fluorescence. A reduced fluorescence is observed in red, photoconverted Kaede when it is intensively exposed to 405 nm light, followed by partial recover after several minutes. Applications As all other fluorescent proteins, Kaede can be the regional optical markers for gene expression and protein labeling for the study of cell behaviors.[3] One of the most useful applications is the visualization of neurons. Delineation of an individual neuron is difficult due to the long and thin processes which entangle with other neurons. Even when cultured neurons are labeled with fluorescent proteins, they are still difficult to identify individually because of the dense package. In the past, such visualization could be done conventionally by filling neurons with Lucifer yellow or sulforhodamine, which is a laborious technique.[1] After the discovery of Kaede protein, it was found to be useful in delineating individual neurons. The neurons are transfected by Kaede protein cDNA, and are UV irradiated. The red, photoconverted Kaede protein has free diffusibility in the cell except for the nucleus, and spreads over the entire cell including dendrites and axon. This technique help disentangle the complex networks established in a dense culture. Besides, by labeling neurons with different colors by UV irradiating with different duration times, contact sites between the red and green neurons of interest are allowed to be visualized. The ability of visualization of individual cells is also a powerful tool to identify the precise morphology and migratory behaviors of individual cells within living cortical slices. By Kaede protein, a particular pair of daughter cells in neighboring Kaede-positive cells in the ventricular zone of mouse brain slices can be followed. The cell-cell borders of daughter cells are visualized and the position and distance between two or more cells can be described. As the change in the fluorescent colour is induced by UV light, marking of cells and subcellular structures is efficient even when only a partial photoconversion is induced. Advantages as an optical marker Due to the special property of photo-switchable fluorescence, Kaede protein possesses several advantages as an optical cell marker. After the photoconversion, the photoconverted Kaede protein emits bright and stable red fluorescence. This fluorescence can last for months without anaerobic conditions. As this red state of Kaede is bright and stable compared to the green state, and because the unconverted green Kaede emits very low intensity of red fluorescence, the red signals provides contrast.[1] Besides, before the photoconversion, Kaede emits bright green fluorescence which enables the visualization of the localization of the non-photoacivated protein. This is superior to other fluorescent proteins such as PA-GFP and KFP1, which only show low fluorescence before photoactivation. In addition, as both green and red fluorescence of Kaede are excited by blue light at 480 nm for observation, this light will not induce photoconversion. Therefore, illumination lights for observation and photoconversion can be separated completely. Limitations In spite of the usefulness in cell tracking and cell visualization of Kaede, there are some limitations. Although Kaede will shift to red upon the exposure of UV or violet light and display a 2,000-fold increase in red-to-green fluorescence ratio, using both the red and green fluorescence bands can cause problems in multilabel experiments. The tetramerization of Kaede may disturb the localization and trafficking of fusion proteins. This limits the usefulness of Kaede as a fusion protein tag. Ecological significance The photoconversion property of Kaede does not only contribute to the application on protein labeling and cell tracking, it is also responsible for the vast variation in the colour of stony corals, Trachyphyllia geoffroyi. Under sunlight, due to the photoconversion of Kaede, the tentacles and disks will turn red. As green fluorescent Kaede is synthesized continuously, these corals appear green again as more unconverted Kaede is created. By the different proportion of photoconverted and unconverted Kaede, great diversity of colour is found in corals. Increasing photoconversion efficiency of DSSC "Dye sensitized solar cell (DSSC) has gained much research interest in recent years for its positive characteristics in contributing to renewable energy generator" said Dr. Gamolwan Tumcharern a researcher at NanoSens Lab at NANOTEC. "The ability to synthesize hybridized material of titanate nanoparticles and CNT using hydrothermal process has greatly increased the photoconversion efficiency of DSSC". Because DSSC could potentially be made of low-cost materials, and does not require elaborate apparatus to manufacture, this cell is technically attractive as a renewable energy generator. Likewise, manufacturing DSSC can be significantly less expensive than older solid-state cell designs. It can also be engineered into flexible sheets and is mechanically robust, requiring no protection from minor events like hail or tree strikes. For this reason, the ability to increase the efficiency of photoconversion is of most interest to the energy sector. A ‘quantum well’ is a potential well that confines particles to two dimensions that are otherwise free to move in three dimensions. Both electrons and holes can be confined in semiconductor quantum wells. The effect is to increase the gain and efficiency of the solid state device such as lasers in CD or DVD players, infrared imaging, and more recently, solar cells. Quantum dot solar cell Spin-cast quantum dot solar cell built by the Sargent Group at the University of Toronto. The metal disks on the front surface are the electrical connections to the layers below. A quantum dot solar cell is a solar cell design that uses quantum dots as the absorbing photovoltaic material. It attempts to replace bulk materials such as silicon, copper indium gallium selenide (CIGS) or CdTe. Quantum dots have bandgaps that are tunable across a wide range of energy levels by changing the dots' size. In bulk materials the bandgap is fixed by the choice of material(s). This property makes quantum dots attractive for multi-junction solar cells, where a variety of materials are used to improve efficiency by harvesting multiple portions of the solar spectrum. Solar cell concepts In a conventional solar cell, light is absorbed by a semiconductor, producing an electron-hole (e-h) pair; the pair may be bound and is referred to as an exciton. This pair is separated by an internal electric field (present in p-n junctions or Schottky diodes) and the resulting flow of electrons and holes creates electric current. The internal electric field is created by doping one part of semiconductor interface with atoms that act as electron donors (n-type doping) and another with electron acceptors (p-type doping) that results in a p-n junction. Generation of an e-h pair requires that the photons have energy exceeding the bandgap of the material. Effectively, photons with energies lower than the bandgap do not get absorbed, while those that are higher can quickly (within about 10−13 s) thermalize to the band edges, reducing output. The former limitation reduces current, while the thermalization reduces the voltage. As a result, semiconductor cells suffer a trade-off between voltage and current (which can be in part alleviated by using multiple junction implementations). The detailed balance calculation shows that this efficiency can not exceed 31% if one uses a single material for a solar cell. Numerical analysis shows that the 31% efficiency is achieved with a bandgap of 1.3-1.4 eV, corresponding to light in the near infrared spectrum. This band gap is close to that of silicon (1.1 eV), one of the many reasons that it dominates the market. However, silicon's efficiency is limited to about 29%. It is possible to improve on a single-junction cell by vertically stacking cells with different bandgaps – termed a "tandem" or "multi-junction" approach. The same analysis shows that a two layer cell should have one layer tuned to 1.64 eV and the other to 0.94 eV, providing a theoretical performance of 44%. A three-layer cell should be tuned to 1.83, 1.16 and 0.71 eV, with an efficiency of 48%. An "infinity-layer" cell would have a theoretical efficiency of 86%, with other thermodynamic loss mechanisms accounting for the rest. Traditional (crystalline) silicon preparation methods do not lend themselves to this approach due to lack of bandgap tunability. Thin-films of amorphous silicon, which due to a relaxed requirement in crystal momentum preservation can achieve direct bandgaps and intermixing of carbon, can tune the bandgap, but other issues have prevented these from matching the performance of traditional cells.[5] Most tandem-cell structures are based on higher performance semiconductors, notably indium gallium arsenide (InGaAs). Three-layer InGaAs/GaAs/InGaP cells (bandgaps 1.89/1.42/0.94 eV) hold the efficiency record of 42.3% for experimental examples. Quantum dots Quantum dots are semiconducting particles that have been reduced below the size of the Exciton Bohr radius and due to quantum mechanics considerations, the electron energies that can exist within them become finite, much alike energies in an atom. Quantum dots have been referred to as "artificial atoms". These energy levels are tuneable by changing their size, which in turn defines the bandgap. The dots can be grown over a range of sizes, allowing them to express a variety of bandgaps without changing the underlying material or construction techniques. In typical wet chemistry preparations, the tuning is accomplished by varying the synthesis duration or temperature. The ability to tune the bandgap makes quantum dots desirable for solar cells. Single junction implementations using lead sulfide (PbS) CQDs have bandgaps that can be tuned into the far infrared, frequencies that are typically difficult to achieve with traditional. Half of the solar energy reaching the Earth is in the infrared, most in the near infrared region. A quantum dot solar cell makes infrared energy as accessible as any other. Moreover, CQDs offer easy synthesis and preparation. While suspended in a colloidal liquid form they can be easily handled throughout production, with a fumehood as the most complex equipment needed. CQDs are typically synthesized in small batches, but can be mass-produced. The dots can be distributed on a substrate by spin coating, either by hand or in an automated process. Large-scale production could use spray-on or roll-printing systems, dramatically reducing module construction costs. Production Early examples used costly molecular beam epitaxy processes, but less expensive fabrication methods were later developed. These use wet chemistry (colloidal quantum dots – CQDs) and subsequent solution processing. Concentrated nanoparticle solutions are stabilized by long hydrocarbon ligands that keep the nanocrystals suspended in solution. To create a solid, these solutions are cast down and the long stabilizing ligands are replaced with short-chain crosslinkers. Chemically engineering the nanocrystal surface can better passivate the nanocrystals and reduce detrimental trap states that would curtail device performance by means of carrier recombination. This approach produces an efficiency of 7.0%. A more recent study uses different ligands for different functions by tuning their relative band alignment to improve the performance to 8.6%. The cells were solution-processed in air at room-temperature and exhibited air-stability for more than 150 days without encapsulation. In 2014 the use of iodide as a ligand that does not bond to oxygen was introduced. This maintains stable n- and p-type layers, boosting the absorption efficiency, which produced power conversion efficiency up to 8%. The idea of using quantum dots as a path to high efficiency was first noted by Burnham and Duggan in 1990. At the time, the science of quantum dots, or "wells" as they were known, was in its infancy and early examples were just becoming available. Using quantum dots as an alternative to molecular dyes was considered from the earliest days of DSSC research. The ability to tune the bandgap allowed the designer to select a wider variety of materials for other portions of the cell. Collaborating groups from the University of Toronto and École Polytechnique Fédérale de Lausanne developed a design based on a rear electrode directly in contact with a film of quantum dots, eliminating the electrolyte and forming a depleted heterojunction. These cells reached 7.0% efficiency, better than the best solid-state DSSC devices, but below those based on liquid electrolytes. Model and main results Energy d of QWSCs: dp, db, and dn are the thicknesses of the p+, base, and n+ regions, respectively. the blackbody spectrum at a temperature of 5800 K. One electron-hole pair generation by every photon in the interband absorption range was assumed. Light reflection and contact grid shadowing were neglected. We took the photocurrent collection coefficient to be 1. The recombination in the base region consisting of the bulk recombination in barriers, recombination in quantum wells, and “surface” recombination on the barrier − quantum well interfaces was taken into consideration. Recombination velocities are Vr and S, respectively. Quantum wells are assumed to be located outside the screening area. The concentration Δp of excess electron-hole pairs in the base region is determined as Δp = JSC / qVeff, (1) where Veff = Vr + S; JSC is the surface short-circuit current density, and q is the electron charge. The open circuit voltage VOC = (kT / q)[ln(Δp / p0) + ln(1 + Δp / n0)], (2) where k is the Boltzmann constant, T is the absolute temperature, and p0 and n0 are, respectively, the concentrations of majority and minority current carriers. The short-circuit current density JSC is a function of the barrier material bandgap Egb, quantum wells bandgap Egq, and the effective times of recombination τeff and quantum well carrier escape τesc : [ ( ) ( )] . ( ) eff esc eff τ + τ τ+ −= +SC gq SC gb SC SC gb J E J E J J E (3) We have calculated the limiting photoconversion efficiency of QWSCs under AM0 conditions by using relations (1)-(3). We set τeff = db /Veff , where db is the base region thickness, and take τesc =W 2πm / kT exp(Ea / kT) [6] (W is the quantum well width, m is the effective mass of a quantum well carrier, and Ea ≈ (Eb − Eg) / 2 is the activation energy). The band structure of a QWSC is demonstrated in corresponds to a low doping of the base region and the Δp < n0 condition. In this case, a strong electric field acts in the base region in the maximum power takeoff mode. In this case, there is no electric field in the base region in the maximum power takeoff mode. When Δp < n0, the open-circuit voltage VOC ≈ (kT / q)ln(Δpn0 / ni 2), where ni is the intrinsic carrier concentration of a barrier material, and ni logarithmically depends on the doping level of the base region. The greater is n0, the greater is VOC . In the case of a high excitation level when Δp > n0, the open-circuit voltage VOC ≈ (2kT / q)ln(Δp / ni), and it does not depend on the doping of the base region. The non-equilibrium carrier lifetime in direct band semiconductors is low enough, so the Δp << n0 criterion is satisfied under AM0 and AM1.5 conditions. High excitation levels in such semiconductors can be reached under concentrated illumination. Therefore, the QWSCs with direct band semiconductor p-i-n structures and with a low doped base region have low photovoltage and photoconversion efficiency relative to those in structures with a highly doped base region. There is another situation in Si SCs, where a high excitation level can be realized under AM0 or AM1.5 condition. Thereby, the photovoltage and the photoconversion efficiency of Si p-i-n structures are high enough and cannot be increased by a higher doping of the base region, the limiting photoconversion efficiency of QWSCs with p-i-n structure versus the quantum well material bandgap Egq for AM0 (Fig. 2a) and at the light concentration M = 400 (M is the degree of concentration of the illumination). The barrier material is GaAs. the photoconversion efficiency of SCs with p-i-n structure versus the quantum well material bandgap Egq for AM0, the barrier material being Al0.35Ga0.65As5. The curves are built for various Veff. The background doping level is 1015 cm−3. Efficiencies in these figures are compared with the limiting photoconversion efficiency of conventional SCs at a base region doping level of 1017 cm−3. 3 Limiting photoconversion efficiency of GaAs QWSCs versus the quantum well bandgap under AM0 conditions (2a) and at the light concentration М = 400 (2b). di = 0.5 μm, n0 =1015 cm−3, Veff = 3•104 cm/s (1), 105 (2), and 106 (3). However, in a more realistic case for Veff ≈ 105 cm/s, the photoconversion efficiency is 29 % at AM0 and 35 % under light concentration. These values do not differ strongly from the corresponding values for conventional SCs (26 − 27 % under AM0 conditions and 31 % under light concentration). With the further increase in Veff, the limiting photoconversion efficiency of QWSCs becomes less than the limiting photoconversion efficiency of conventional SCs. First of all, it covers GaAs-InGaAs and Si-GeSi structures with high percentages of In and Ge. We tried to take into account the fact that Veff increases, as Egq decreases. So, by taking Veff = V0[1 + a(ΔE / Ex)m], where ΔE = Eg − Egq, V0 = 10 cm/s, and a, Ex, and m are variable parameters, we had a maximum of the limiting photoconversion efficiency of Si QWSCs versus Egq, and this maximum was a little higher than the maximum for conventional SCs. Dependences in Fig. 4 are illustrative. Generally, there are many possible choices of Veff as a function of ΔE. The point is that these dependences illustrate the possibility of the decrease in the open circuit voltage stronger than the increase in the short circuit current with increase in ΔE. The results of numerical modeling of the photoconversion efficiency of GaAs-InGaAs QWSCs by using the SimWindows program are described in what follows. We should like to mention the unavoidable factors decreasing the photoconversion efficiency which were taken into account in the modeling. First of all, it is the bulk recombination that consists of the Shockley-Reed recombination, radiative recombination, and Auger recombination. We assumed the front and rear surface recombination velocities to be 103 cm/s, what is quite a low value for direct band A3B5 semiconductors. The thickness dp of the heavily doped p+-region was varied and assumed to be 1 μm, which corresponds to the photoconversion efficiency optimum taking into account the series resistance of the p+-region and the recombination. The thickness dn of the n+-region was also 1 μm. The doping level of the p+- and n+-regions was 7•1018 cm−3. Calculations were carried out for 50 InGaAs quantum wells of 9 nm in width separated by 6-nm-wide barriers symmetrically disposed relative to the base region center. The base region thickness db was also varied, and its mean value is assumed to be 1.15 μm. Losses of 12 % due to reflection and contact grid shadowing were assumed. In the modeling of QWSCs under concentrated sunlight, GaAs and InGaAs were used as materials for barriers and quantum wells, respectively. The computational parameters were identical to those in the case without light concentration. CHAPTER THREE 3. Conclusions 1. The photoconversion efficiency of A3B5 p-i-n QWSCs is quite low because of a low photovoltage. The base region should be doped strongly enough to increase this efficiency. However, the photoconversion efficiency of QWSCs at a high doping (> 3•1017 cm−3) of the base region is proved to be less than that of conventional SCs. 2. Light concentration enables one to get a considerable increase in the photoconversion efficiency of A3B5 p-i-n QWSCs, by making it comparable to that of SCs with the highly doped base region. 3. Most effective QWSCs have a constant-sign electric field localized in narrow areas near the boundaries of the base region. There is no strong electric field in the area of quantum wells, and this situation is shown in Fig. 1b. 4. The difference in the photoconversion efficiencies of QWSCs and conventional A3B5 SCs at the same doping of the base region is small and does not exceed 5 % for parameters used in this computation (see Fig. 5). References 1. J.P. Connolly, I.M. Ballard, K.W.J. Barnham, et al., Efficiency limits of quantum well solar cells // Proc. 19th European Photovoltaic Solar Energy Conference (Paris, France, 2004), p. 355. 2. T.N.D. Tibbits, I.M. Ballard, K.W.J. Barnham, et al., Strain-balanced multi-quantum well solar cells tandem structures – first experimental results // Proc. 19th European Photovoltaic Solar Energy Conference (Paris, France, 2004), p. 3715. 3. M.C. Lynch, I.M. Ballard, A. Bessière, M. Hoyes, D.C. Johnson, P.N. Stavrinou1, T.N.D. Tibbits, I. Tongue, K.W.J. Barnham, et al., Strain balanced quantum well solar cells for high concentration applications // Proc. 20th European Photovoltaic Solar Energy Conference (Barcelona, Spain, 2005), p. 523. 4. D.W. Winston, Physical simulation of optoelectronic semiconductor devices // Ph. D. Dissertation, University of Colorado, 1996. 5. D.W. Winston //www-os.colorado.edu/SimWindows/ simwin.html. 6. M.A. Green, K. Emery, D.L. King, S. Igary, W. Warta // Progr. Photovolt.: Res. Appl. 10, p. 355 (2002). 7. A. Alemu, L. Williams, L. Bhusal, A. Freundlich, Limitations of multi-quantum well solar cells for concentrator application // Proc. 19th European Photovoltaic Solar Energy Conference (Paris, France, 2004), p. 359. References • Tomura, M.; Yoshida, N.; Tanaka, J.; Karasawa, S.; Miwa, Y.; Miyawaki, A.; Kanagawa, O. (2008). "Monitoring cellular movement in vivo with photoconvertible fluorescence protein "Kaede" transgenic mice". Proceedings of the National Academy of Sciences 105 (31): 10871. doi:10.1073/pnas.0802278105. edit • Dittrich, P. S.; Schäfer, S. P.; Schwille, P. (2005). "Characterization of the Photoconversion on Reaction of the Fluorescent Protein Kaede on the Single-Molecule Level". Biophysical Journal 89 (5): 3446–3455. doi:10.1529/biophysj.105.061713. PMC 1366840. PMID 16055537. edit 1. Ando, R. (2002). "An optical marker based on the UV-induced green-to-red photoconversion of a fluorescent protein". Proceedings of the National Academy of Sciences 99 (20): 12651–12656. doi:10.1073/pnas.202320599. edit 2. Mizuno, H.; Mal, T. K.; Tong, K. I.; Ando, R.; Furuta, T.; Ikura, M.; Miyawaki, A. (2003). "Photo-induced peptide cleavage in the green-to-red conversion of a fluorescent protein". Molecular cell 12 (4): 1051–1058. PMID 14580354. edit 3. Lippincott-Schwartz, J.; Altan-Bonnet, N.; Patterson, G. H. (2003). "Photobleaching and photoactivation: Following protein dynamics in living cells". Nature cell biology. Suppl: S7–14. PMID 14562845. edit 4. Mutoh, T.; Miyata, T.; Kashiwagi, S.; Miyawaki, A.; Ogawa, M. (2006). "Dynamic behavior of individual cells in developing organotypic brain slices revealed by the photoconvertable protein Kaede". Experimental Neurology 200 (2): 430–437. doi:10.1016/j.expneurol.2006.03.022. PMID 16753144. edit

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INTRODUCTION Biosurfactants are surface active molecules having hydrophilic and hydrophobic moieties as their constituents which allow them to interact at interfaces and reduce the surface tension. They are produce by diverse group of organism belong to bacteria, fungi and actinomycetes etc., mainly on surfaces of microorganisms or may also secreted extracellularly. They are categorized based on their chemical composition as fatty acids, glycolipids, glycolipopeptides, glycoproteins, lipopeptides, phospholipids, polymeric and particulate biosurfactants. The chemicaldiversity of biosurfactants makes them a potential source for green chemicals having applications in industrial, environmental (agricultural and bioremediation), and medical fields. Almost all surfactants being currently produced are derived from petroleum source. However, these synthetic surfactants are usually toxic and hardly degraded by microorganisms. These are potential source of pollution and damage to the environment. Therefore, in the recent years, much interest and attention have been directed towards biosurfactants over chemically synthesized surfactants due to their superiority to the chemical surfactants with respect to their biocompatibility, lower toxicity, higher biodegradability, higher stability, extreme stability in extreme temperature and pH. With the advent of time, this attribute is contributing its higher demand in the field of biotechnology. The agricultural waste such as whey (a by-product of the manufacture of cheese or casein) are well known for containing high levels of carbohydrates and of lipids -both of which are necessary for substrates for the production of biosurfactants and contains all necessary substances (lactose, protein, organic acids and vitamins) that require for growth of surfactant producing microorganism. This study focus on the screening, production, extraction and purification of biosurfactant from bacteria isolated from whey spilled soil and which is easily available in India. 2.0 LITERATURE REVIEW Surfactants are usually organic compounds that are amphiphilic, meaning they contain both hydrophobic groups (their tails) and hydrophilic groups (their heads). The hydrophilic (polar) end part of the biosurfact ant is insoluble in water and may have a long chain of fatty acids, hydroxyl fatty acids or α-alkyl-β -hydroxy fatty acids. The hydrophilic (polar) end can be a carbohydrate, amino acid, cyclic peptide, phosphate, carboxylic acid or alcohol (Jaysree et al., 2011). Surfactant or surface active agents can be classified into two main groups; synthetic surfactant and bio-surfactant. Synthetic surfactant is produced by chemical reactions, while bio-surfactant is produced by biological processes, being excreted extracellularly by microorganisms such as bacteria, fungi and yeast (Jayrees et al., 2011). Chemically-synthesized surfactants have been used in the oil industry to aid clean up of oil spills, as well as to enhance oil recovery from oil reservoirs. These compounds are not biodegradable and can be toxic to environment (Tabatabaee et al., 2005). When compared to synthetic surfactant, bio-surfactant have several advantages including high bio-degradability, low toxicity, low irritancy, ecological acceptability, compatibility with human skin and ability to be produced from renewable and cheaper substrates (Banat et al.,2000) Therefore, it is reasonable to expect diverse properties and physiological functions of bio-surfactants such as increasing the surface area and bio-availability of hydrophobic water-insoluble substrates, metal binding, bacterial pathogenesis, quorum sensing, and bio-film formation (Priya & Usharani, 2009). Unlike synthetic surfactants, microbial-produced compounds are easily degraded and particularly suited for environmental applications such as bioremediation and dispersion of oil spills (Mohan et al., 2006). The aim of this study is to isolate and screen bacterial species from different hydrocarbon polluted sites for bio-surfactants production. 2.1. STUDY LOCATION Soil samples (A-D) are to be collected from oil spilled surfaces of different automobile workshops in Owerri Imo-State, Nigeria. The samples are to be collected in sterile polythene bags and are to be taken to the laboratory for analysis. 3.O. Materials and methods 3.1. Sampling area For isolation biosurfactant producing bacteria soil samples are to be collected from whey spilled surfaces of five different cheese making farm of Owerri West, Imo state (sample 1-5). The samples are to be collected in sterile container under aseptic condition and are to be taken to the laboratory for analysis. The pH of the samples during collection is to be 7.0 and temperature should be 300C. 3.1.1. Isolation and enumeration of bacterial isolates from the sample 5g of the oil spilled soil samples are to be inoculated in 50ml of nutrient broth and incubated at 25 ̊C for72 hours. After incubation the medium is serially diluted from 10-1 to10-6 in sterile water. From the dilutions (10-1 to10-6) 1ml are to be transferred to sterile petri-dish and over that 20mls of nutrient agar are to be poure. The plates then inverted and incubated at 25 ̊C for 48 hours. Control and replica plates - maintained. 3.1.3 Bacteriological isolation techniques After incubation, the different discrete colonies formed on the plate that had between 30 and 300 colony forming unit (cfu) are to be streaked on nutrient agar slant and incubated at ambient temperature (37 ̊C) for 24 hours to obtain their pure cultures. These pure cultures, are to be sub-cultured on nutrient agar slant, incubated at 37 ̊C for 24 hours and stored at 4 ̊C for bio-surfactants production screening 3.2 MATERIALS Soil sample Petri-dish Polytin bag 4.0. CONCLUSION Uses of biosurfactants are increasingly in almost every sectors of the modern industry as an alternative to chemical surfactants. With increasing public awareness in the environment, biosurfactant would most likely replace the usage of chemical surfactants in the near future. As biosurfactants are derived from natural sources, each of these types is an attractive alternative to synthetic compounds. Biosurfactants are surfactants that are produced extracelluarly or as part of the cell membrane by bacteria, yeast and fungi. The main commercial use of biosurfactant is in oil industry, foods, cosmetics, pharmacology and environmental technology because of their ability to stabilize emulsions. The features that make them commercially promising alternatives to chemically synthesized surfactants are their lower toxicity, higher biodegradability and greater environmental compatibility. Production and characterization of biosurfactants produced by these bacterial isolates is recommended REFERENCES Desai JD, Banat IM (1997) Microbial production of surfactants and their commercial potential. MicrobiolMolBiol Rev 61: 47-64. InkaSiegmund, Fritz Wagner (1991)New method for detecting rhamnolipids excreted by Pseudomonas species during growth on mineral agar.Biotechnology Techniques Jul/Aug 1991, Volume 5, Issue 4, pp 265-268. B Anandaraj, P Thivakaran (2010) Isolation and production of biosurfactant producing organism from oil spilled soil. jBiosci Tech, Vol 1 (3),2010,120‐126 T Priya, G Usharani (2009) Comparative study for biosurfactant production by using Bacillus subtilis and Pseudomonas aeruginosa.Botany Research International 2 (4): 284-287, 2009 P. G. Carrillo, C. Mardaraz, S. I. Pitta-Alvarez, A. M. Giulietti (1996) Isolation and selection of biosurfactant-producing bacteria. World Journal of Microbiology and Biotechnology, January 1996, Volume 12, Issue 1,pp 82-84 Youssef NH, Duncan KE, Nagle DP, Savage KN, Knapp RM & McInerney MJ (2004) Comparison of methods to detect biosurfactant production by diverse microorganisms. J Microbiol Meth 56:339–347. Paraszkiewicz K, KanwalA & Dlugonski J (1992) Emulsifier production by steroid transforming filamentous fungus Curvularialunata, growth and product characterization.J Biotechnol 92:287–294. Morikawa M, Daido H, Takao T, Murata S, Shimonishi Y & Imanaka T (1993) A new lipopeptide biosurfactant produced by Arthrobactersp. strain MIS 38.J Bacteriol 175:6459–6466. Desai JD & Banat IM (1997) Microbial production of surfactants and their commercial potential. MicrobiolMolBiol R 61:47–64. Cooper DG, Goldenberg BG (1987). Surface active agents from two Bacillus species. Appl. Environ. Microbiol., 53: 224-229. Yin, H., Qiang, Y., Jia, J., Ye, H., Peng, H., Qin,N., Zhang, N., & He, B. (2008). Characteristics of biosurfactant produced by Pseudomonas aeruginosa S6 isolated from oil –containing wastewater. Process Biochemistry, 44,302-308. OkoreChioma et.al (2013) Isolation and Characterization of Biosurfactants Producing Bacteria from Oil Polluted Soil. Journal of Natural Sciences Research Vol.3, No.5, (119-122) Banat I. M. (1995), Biosurfactants production and possible uses in microbial enhanced oil recovery and oil pollution remediation: a review. Bioresource Technol. 51. 1–12. Gautam, K. K. and Tyagi, V. K. (2005), Microbial surfactants: A review. J. Oleo. Sci., ,55, 155–166. Rodrigues, L. (2006). Biosurfactants potential applications in medicine. J. Antimicrobial. Chemotherapy, 57, 607-618.

gender

Gender inequality Gender inequality refers to unequal treatment or perceptions of individuals based on their gender. It arises from differences in socially constructed gender roles as well as biologically through chromosomes, brain structure, and hormonal differences.[1] Gender systems are often dichotomous and hierarchical; gender binary systems may reflect the inequalities that manifest in numerous dimensions of daily life. Gender inequality stems from distinctions, whether empirically grounded or socially constructed. (On differences between the sexes, see Sex and psychology.) Natural sex differences Main article: Sex differences in humans There are natural differences between the sexes based on biological and anatomic factors, most notably differing reproductive roles. Biological differences include chromosomes, brain structure, and hormonal differences.[1] There is a natural difference also in the relative physical strengths (on average) of the sexes.[2][3] In the workplace Income disparities linked to job stratification Wage discrimination exists when workers are equally qualified and perform the same work but one group of workers is paid more than another. Historically, wage discrimination has favored men over similarly qualified women.[4] Income disparity between genders stems from processes that determine the quality of jobs and earnings associated with jobs.[clarification needed] Earnings associated with jobs will cause income inequality to take form in the placement of individuals into particular jobs through individual qualifications or stereotypical norms.[citation needed] Placement of men or women into particular job categories can be supported through the human capital theories of qualifications of individuals or abilities associated with biological differences in men and women.[citation needed] Conversely, the placement of men or women into separate job categories is argued to be caused by social status groups who desire to keep their position through the placement of those in lower statuses to lower paying positions.[5] Human capital theories refer to the education, knowledge, training, experience, or skill of a person which makes them potentially valuable to an employer. This has historically been understood as a cause of the gendered wage gap but is no longer a predominant cause as women and men in certain occupations tend to have similar education levels or other credentials. Even when such characteristics of jobs and workers are controlled for, the presence of women within a certain occupation leads to lower wages. This earnings discrimination is considered to be a part of pollution theory. This theory suggests that jobs which are predominated by women offer lower wages than do jobs simply because of the presence of women within the occupation. As women enter an occupation, this reduces the amount of prestige associated with the job and men subsequently leave these occupations. The entering of women into specific occupations suggests that less competent workers have begun to be hired or that the occupation is becoming deskilled. Men are reluctant to enter female-dominated occupations because of this and similarly resist the entrance of women into male-dominated occupations.[6][page needed] The gendered income disparity can also be attributed in part to occupational segregation, where groups of people are distributed across occupations according to ascribed characteristics; in this case, gender.[citation needed] Occupational gender segregation can be understood[who?] to contain two components or dimensions; horizontal segregation and vertical segregation. With horizontal segregation, occupational sex segregation occurs as men and women are thought to possess different physical, emotional, and mental capabilities. These different capabilities make the genders vary in the types of jobs they are suited for. This can be specifically viewed with the gendered division between manual and non-manual labor.[citation needed] With vertical segregation, occupational sex segregation occurs as occupations are stratified according to the power, authority, income, and prestige associated with the occupation and women are excluded from holding such jobs.[6] As women entered the workforce in larger numbers since the 1960s, occupations have become segregated based on the amount femininity or masculinity presupposed to be associated with each occupation.[citation needed] Census data suggests that while some occupations have become more gender integrated (mail carriers, bartenders, bus drivers, and real estate agents), occupations including teachers, nurses, secretaries, and librarians have become female-dominated while occupations including architects, electrical engineers, and airplane pilots remain predominately male in composition.[7] Based on the census data, women occupy the service sector jobs at higher rates than men. Women’s overrepresentation in service sector jobs, as opposed to jobs that require managerial work acts as a reinforcement of women and men into traditional gender roles that causes gender inequality.[8] Median weekly earnings of full-time wage and salary workers, by sex, race, and ethnicity, U.S., 2009.[9] Once factors such as experience, education, occupation, and other job-relevant characteristics have been taken into account, 41% of the male-female wage gap remains unexplained. As such, considerations of occupational segregation and human capital theories are together not enough to understand the continued existence of a gendered income disparity.[6] The glass ceiling effect is also considered a possible contributor to the gender wage gap or income disparity. This effect suggests that gender provides significant disadvantages towards the top of job hierarchies which become worse as a person’s career goes on. The term glass ceiling implies that invisible or artificial barriers exist which prevent women from advancing within their jobs or receiving promotions. These barriers exist in spite of the achievements or qualifications of the women and still exist when other characteristics that are job-relevant such as experience, education, and abilities are controlled for. The inequality effects of the glass ceiling are more prevalent within higher-powered or higher income occupations, with fewer women holding these types of occupations. The glass ceiling effect also indicates the limited chances of women for income raises and promotion or advancement to more prestigious positions or jobs. As women are prevented by these artificial barriers, from either receiving job promotions or income raises, the effects of the inequality of the glass ceiling increase over the course of a woman’s career.[10] Statistical discrimination is also cited as a cause for income disparities and gendered inequality in the workplace. Statistical discrimination indicates the likelihood of employers to deny women access to certain occupational tracks because women are more likely than men to leave their job or the labor force when they become married or pregnant. Women are instead given positions that dead-end or jobs that have very little mobility.[4] In Third World countries such as the Dominican Republic, female entrepreneurs are statistically more prone to failure in business. In the event of a business failure women often return to their domestic lifestyle despite the absence of income. On the other hand, men tend to search for other employment as the household is not a priority.[11] The gender earnings ratio suggests that there has been an increase in women’s earnings comparative to men. Men’s plateau in earnings began after the 1970s, allowing for the increase in women’s wages to close the ratio between incomes. Despite the smaller ratio between men and women’s wages, disparity still exists. Census data suggests that women’s earnings are 71 percent of men’s earnings in 1999.[7] The gendered wage gap varies in its width among different races. Whites comparatively have the greatest wage gap between the genders. With whites, women earn 78% of the wages that white men do. With African Americans, women earn 90% of the wages that African American men do. With people of Hispanic origin, women earn 88% of the wages that men of Hispanic origin do. There are some exceptions where women earn more than men: According to a survey on gender pay inequality by the International Trade Union Confederation, female workers in the Gulf state of Bahrain earn 40 per cent more than male workers.[12] Professional education and careers The gender gap also appeared to narrow considerably beginning in the mid-1960s. Where some 5% of first-year students in professional programs were female in 1965, by 1985 this number had jumped to 40% in law and medicine, and over 30% in dentistry and business school.[13] Before the highly effective birth control pill was available, women planning professional careers, which required a long-term, expensive commitment, had to "pay the penalty of abstinence or cope with considerable uncertainty regarding pregnancy."[14] This control over their reproductive decisions allowed women to more easily make long-term decisions about their education and professional opportunities. Women are highly underrepresented on boards of directors and in senior positions in the private sector.[15] Additionally, with reliable birth control, young men and women had more reason to delay marriage. This meant that the marriage market available to any one women who "delay[ed] marriage to pursue a career...would not be as depleted. Thus the Pill could have influenced women's careers, college majors, professional degrees, and the age at marriage."[16] Specifically in China, birth control has become a necessity of the job for women that migrate from rural to urban China. With little job options left, they become sex workers and having some form of birth control helps to ensure their safety. However, the government of China does not regulate prostitution in China, making it more difficult for women to gain access to birth control or to demand that the men use condoms. This doesn't allow for the women to be fully protected, since their health and safety is in jeopardy when they disobey.[17] A recent study in the USA demonstrated that when leaders at scientific research institutes were presented with otherwise identical job applications (a randomized double-blind designed with n=127) with either female or male names, faculty participants rated the male applicant as significantly more competent and hireable than the (identical) female applicant. These participants also selected a higher starting salary and offered more career mentoring to the male applicant. The tendency to be biased towards the male application was expressed by both male and female faculty staff.[18] Customer preference studies A 2009 study conducted by David R. Hekman and colleagues found that customers who viewed videos featuring a black male, a white female, or a white male actor playing the role of an employee helping a customer were 19 percent more satisfied with the white male employee's performance.[19][20][21][22][23] This discrepancy with race can be found as early as 1947, when Kenneth Clark conducted a study in which black children were asked to choose between white and black dolls. White male dolls were the ones children preferred to play with.[24][25] Gender discrimination in the medical field Although the disparities between men and women are decreasing in the medical field, gender inequalities still exist as social problems. Recently qualified female doctors in the U.S. make almost $17,000 less than their male counterparts. The pay discrepancy could not be explained by specialty choice, practice setting, work hours, or other characteristics.[26] At home Gender roles in parenting and marriage Sigmund Freud suggested that biology determines gender identity through identification with either the mother or father.[citation needed] While some people agree with Freud,[who?] others[who?] argue that the development of the gendered self is not completely determined by biology, but rather the interactions that one has with the primary caregiver(s). According to the non-Freudian view,[clarification needed] gender roles develop through internalization and identification during childhood. From birth, parents interact differently with children depending on their sex, and through this interaction parents can instill different values or traits in their children on the basis of what is normative for their sex.[citation needed] This internalization of gender norms can be seen through the example of which types of toys parents typically give to their children (“feminine” toys such as dolls often reinforce interaction, nurturing, and closeness, “masculine” toys such as cars or fake guns often reinforce independence, competitiveness, and aggression).[1] On the other hand it has been shown that rhesus macaque children exhibit preferences for stereotypically male and female toys.[27] Education also plays an integral role in the creation of gender norms.[28] In Strong Fathers, Strong Daughters, Meg Meeker emphasizes the importance of opposite-gender parental roles. She claims "fathers, more than anyone else, set the course for a daughter's life."[29] Gender roles permeate throughout life and help to structure parenting and marriage, especially in relation to work in and outside the home. Gender inequality in relationships Gender equality in relationships has been improving over the years but for the majority of relationships, the power lies with the male.[30] Even how men and women present themselves is divided along gender lines. A study done by Szymanowicz and Furnham, looked at the cultural stereotypes of intelligence in men and women, showing the gender inequality in self-presentation.[31] This study showed that females thought if they revealed their intelligence to a potential partner, then it would diminish their chance with him. Men however would much more readily discuss their own intelligence with a potential partner. Also, women are aware of people’s negative reactions to IQ, so they limit its disclosure to only trusted friends. Females would disclose IQ more often than men with the expectation that a true friend would respond in a positive way. Intelligence continues to be viewed as a more masculine trait, than feminine trait. The article suggested that men might think women with a high IQ would lack traits that were desirable in a mate such as warmth, nurturance, sensitivity, or kindness. Another discovery was that females thought that friends should be told about one’s IQ more so than males. However, males expressed doubts about the test’s reliability and the importance of IQ in real life more so than women. The inequality is highlighted when a couple starts to decide who is in charge of the family issue and who is primarily responsible for bringing back paycheck. For example, in Londa Schiebinger’s book, “Has Feminism Changed Science?”, she claims that “Married men with families on average earn more money, live longer, and progress faster in their careers,” while “for a working woman, a family is a liability, extra baggage threatening to drag down her career.”[32] Furthermore, statistics had shown that “only 17 percent of the women who are full professors of engineering have children, while 82 percent of the men do.”[33] Women in a relationship are continuously playing the role of assistant which is “for the most part invisible.”[citation needed] Attempts in equalizing household work Despite the increase in women in the labor force since the mid-1900s, traditional gender roles are still prevalent in American society. Women may be expected to put their educational and career goals on hold in order to raise children, while their husbands work. However, women who choose to work as well as fulfill a perceived gender role of cleaning the house and taking care of the children. Despite the fact that different households may divide chores more evenly, there is evidence that supports that women have retained the primary caregiver role within familial life despite contributions economically. This evidence suggest that women who work outside the home often put an extra 18 hours a week doing household or childcare related chores as opposed to men who average 12 minutes a day in childcare activities.[34] One study by van Hooff showed that modern couples, do not necessarily purposefully divide things like household chores along gender lines, but instead may rationalize it and make excuses.[30] One excuse used is that women are more competent at household chores and have more motivation to do them. Another is that some say the demands of the males’ jobs is higher. Numerous false rationalizations exist. Gender inequalities in relation to technology One survey showed that men rate their technological skills in activities such as basic computer functions and online participatory communication higher than women. However, it should be noted that this study was a self-reporting study, where men evaluate themselves on their own perceived capabilities. It thus is not data based on actual ability, but merely perceived ability, as participants' ability was not assessed. Additionally, this study is inevitably subject to the significant bias associated with self-reported data.[35] Structural marginalization Gender inequalities often stem from social structures that have institutionalized conceptions of gender differences.[citation needed] Marginalization occurs on an individual level when someone feels as if they are on the fringes or margins of their respective society. This is a social process and displays how current policies in place can affect people. For example, media advertisements display young girls with easy bake ovens (promoting being a housewife) as well as with dolls that they can feed and change the diaper of (promoting being a mother). The politics of NGOs Non-governmental organizations (NGO's) have the ability to create change. Certain NGO's, such as the Kiva (organization) promote female entrepreneurs. Currently, Kiva distributes loans to approximately 400 more women than men. However, even when women work at NGO's in order to create a voice and a space for women's empowerment, there are still gender discrepancies amongst the women. For example, in Uttar Pradesh in India, there is a NGO where women work. Marginalized because of their caste and religion, this organization has the opportunity to provide a voice to the voiceless and expose the issues that are happening. However, women from a higher caste still have issues eating the food of women from a lower caste.[36] This tension shows that there are still fundamental gender inequality issues that working at an NGO may not readily solve. Gender stereotypes Main article: Gender stereotypes See also: Category:Feminism and the arts Cultural stereotypes are engrained in both men and women and these stereotypes are a possible explanation for gender inequality and the resulting gendered wage disparity. Women have traditionally been viewed as being caring and nurturing and are designated to occupations which require such skills.[clarification needed][citation needed] While these skills are culturally valued,[clarification needed] they were typically associated with domesticity, so occupations requiring these same skills are not economically valued.[citation needed] Men have traditionally been viewed as the breadwinner or the worker, so jobs held by men have been historically economically valued and occupations predominated by men continue to be economically valued and pay higher wages.[6][page needed] Biological fertilisation stereotypes Bonnie Spanier coined the term hereditary inequality.[37] Her opinion is that some scientific publications depict human fertilization such that sperms seem to actively compete for the "passive" egg, even though in reality the process is more complicated (e.g. the egg has specific active membrane proteins that select sperm etc.) Sexism and discrimination Gender inequality can further be understood through the mechanisms of sexism. Discrimination takes place in this manner as men and women are subject to prejudicial treatment on the basis of gender alone. Sexism occurs when men and women are framed within two dimensions of social cognition. Discrimination also plays out with networking and in preferential treatment within the economic market. Men typically occupy positions of power within the job economy. Due to taste or preference for other men because they share similar characteristics, men in these positions of power are more likely to hire or promote other men, thus discriminating against women.[6] In television and film The New York Film Academy took a closer look at the women in Hollywood and gathered statistics from the top 500 films from 2007 to 2012; for their history and achievements, or lack of. With only a 5:1 ratio of men working in films than women, the 30.8% of women having speaking characters, who may or may not have been a part of the 28.8% of women who were written to wear provocative clothing compared to the 7% of men who did, or the 26.2% of women who wore little to no clothing opposed to the 9.4% of men who did the same.[38] Hollywood actresses get paid less than actors. Topping the Forbes' highest paid actors list, of 2013, is Robert Downey Jr. with $75 million yet Angelina Jolie tops the highest paid actresses list with only $33 million,[39] tying with Denzel Washington ($33 million) and Liam Neeson ($32 million) who were the last two of the top ten highest paid actors list.[40] During the 2013 Academy Awards, 140 men were nominated for an award but only 35 women were nominated, however, no woman was nominated for directing, cinematography, film editing, writing (original screenplay), or original score that year. But ever since the Academy Awards first opened in 1929, only 7 women producers have won the Best Picture category (all women who have been co-producers with men), only 8 women have been nominated for Best Original Screenplay, and Lina Wertmuller (1976), Jane Campion (1994), Sofia Coppola (2004), and Kathryn Bigelow (2012) were the only 4 women to be nominated for Best Directing, with Bigelow being the first woman to win for her film The Hurt Locker. 77% males make up the Academy Awards' voters.[41] Variations by country or culture The Gender gap index world map for 2013.[42] Main article: Global Gender Gap Report Gender inequality is a result of the persistent discrimination of one group of people based upon gender and it manifests itself differently according to race, culture, politics, country, and economic situation. It is furthermore considered a causal factor of violence against women. While gender discrimination happens to both men and women in individual situations, discrimination against women is an entrenched, global pandemic. In the Democratic Republic of the Congo, rape and violence against women and girls is used as a tool of war.[43] In Afghanistan, girls have had acid thrown in their faces for attending school.[44] Considerable focus has been given to the issue of gender inequality at the international level by organizations such as the United Nations (UN), the Organisation for Economic Co-operation and Development (OECD), and the World Bank, particularly in developing countries. The causes and effects of gender inequality vary by country, as do solutions for combating it. Asia See also: Sex-selective abortion One example of the continued existence of gender inequality in Asia is the “missing girls” phenomenon.[45] India Main article: Gender inequality in India India ranking remains low in gender equality measures by the World Economic Forum, although the rank has been improving in recent years.[46][47] When broken down into components that contribute the rank, India performs well on political empowerment, but is scored near the bottom with China on sex selective abortion. India also scores poorly on overall female to male literacy and health rankings. India with a 2013 ranking of 101 out of 136 countries had an overall score of 0.6551, while Iceland, the nation that topped the list, had an overall score of 0.8731 (no gender gap would yield a score of 1.0).[48] Gender inequalities impact India's sex ratio, women's health over their lifetimes, their educational attainment, and economic conditions. It is a multifaceted issue that concerns men and women alike. The labor force participation rate of women was 80.7% in 2013.[49] Nancy Lockwood of Society for Human Resource Management, the world's largest human resources association with members in 140 countries, in a 2009 report wrote that female labor participation is lower than men, but has been rapidly increasing since the 1990s. Out of India's 397 million workers in 2001, 124 million were women, states Lockwood.[50] India is on target to meet its Millennium Development Goal of gender parity in education before 2016.[51] UNICEF's measure of attendance rate and Gender Equality in Education Index (GEEI) capture the quality of education.[52] Despite some gains, India needs to triple its rate of improvement to reach GEEI score of 95% by 2015 under the Millennium Development Goals. A 1998 report states that rural India girls continue to be less educated than the boys.[53] United States Main article: Gender inequality in the United States The World Economic Forum measures gender equity through a series of economic, educational, and political benchmarks. It has ranked the United States as 19th (up from 31st in 2009) in terms of achieving gender equity.[54] The US Department of Labor has indicated that in 2009, “the median weekly earnings of women who were full-time wage and salary workers was…80 percent of men’s”;[55] The Department of Justice found that in 2009, “the percentage of female victims (26%) of intimate partner violence was about 5 times that of male victims (5%)”.[56] “The United States ranks 41st in a ranking of 184 countries on maternal deaths during pregnancy and childbirth, below all other industrialized nations and a number of developing countries”[57] and women only represent 20% of members of Congress.[54] Impact and counteractions Gender inequality and discrimination is argued to cause and perpetuate poverty and vulnerability in society as a whole.[58] Household and intra-household knowledge and resources are key influences in individuals' abilities to take advantage of external livelihood opportunities or respond appropriately to threats.[58] High education levels and social integration significantly improve the productivity of all members of the household and improve equity throughout society. Gender Equity Indices seek to provide the tools to demonstrate this feature of poverty.[58] Despite acknowledgement by institutions such as the World Bank that gender inequality is bad for economic growth, there are many difficulties in creating a comprehensive response.[59] It is argued that the Millennium Development Goals (MDGs) fail to acknowledge gender inequality as a cross-cutting issue. Gender is mentioned in MDG3 and MDG5: MDG3 measures gender parity in education, the share of women in wage employment and the proportion women in national legislatures.[58] MDG5 focuses on maternal mortality and on universal access to reproductive health.[58] However, even these targets are significantly off-track.[59] Addressing gender inequality through social protection programmes designed to increase equity would be an effective way of reducing gender inequality.[59] Researchers at the Overseas Development Institute argue for the need to develop the following in social protection in order to reduce gender inequality and increase growth:[58] • Community childcare to give women greater opportunities to seek employment; • Support parents with the care costs (e.g. South African child/disability grants); • Education stipends for girls (e.g. Bangladesh’s Girls Education Stipend scheme); • Awareness-raising regarding gender-based violence, and other preventive measures, such as financial support for women and children escaping abusive environments (e.g. NGO pilot initiatives in Ghana); • Inclusion of programme participants (women and men) in designing and evaluating social protection programmes; • Gender-awareness and analysis training for programme staff; • Collect and distribute information on coordinated care and service facilities (e.g. access to micro-credit and microentrepreneurial training for women); and • Developing monitoring and evaluation systems that include sex-disaggregated data. However, politics plays a central role in the interests, institutions and ideas that are needed to reshape social welfare and gender inequality in politics and society limits governments' ability to act on economic incentives.[59] It is interesting to note that NGO's tend to protect women against gender inequality and Structural violence. During war, the opposing side targets women, raping and even killing them. This could be because women are associated with children and killing them prohibits there being a next generation of the enemy.[60] Another opportunity to tackle gender inequality is presented by modern Information and communication technologies. In a carefully controlled study,[61] it has been shown that women embrace digital technology more than men, disproving the stereotype of "technophobic women". Given that digital information and communication technologies have the potential to provide access to employment, education, income, health services, participation, protection, and safety, among others (ICT4D), the natural affinity of women with these new communication tools provide women with a tangible bootstrapping opportunity to tackle social discrimination. In other words, if women are provided with modern information and communication technologies, these digital tools present to them an opportunity to fight longstanding inequalities in the workplace and at home.

how to write official letter

Vibrant Youth Fellowship Christian Pentecostal Mission Int’l Enugu State Hqts Ukwu Uratta Road Owerri Imo State 20/05/2015 Dear sir, INVITATION TO TEACH We the EXCOS of the Vibrant Youth Fellowship, having looked inward, we dimmed it fit to invite you to handle us on seminar/teaching on; Topic: Healthy Relationship. Time: 5:30pm prompt. We pray that God will through you minister to us as you honour our invitation. Thanks in anticipation of a favourable response. Sign, ………………………………….. …………………………………… President Secretary.

cnn2

International Edition London, United Kingdom12° Sign in MyCNN International Edition London, United Kingdom12° Sign in MyCNN News World Sport Technology Entertainment Style Travel Money Regions U.S. China Asia Middle East Africa Europe Americas Video Must Watch Videos Shows CNN en Español TV TV Shows Schedule Faces of CNN Worldwide Features Style Travel All Features Opinions iReport More… Photos Weather CNN Mobile Tools & Extras CNN Profiles A-Z CNN Leadership CNN Arabic CNN Español CNN Mexico CNN Facebook CNN Twitter CNN Google+ CNN Heroes Impact Your World CNN Freedom Project Quick Links Photos Weather CNN Mobile Tools & Extras CNN Profiles A-Z CNN Leadership CNN ArabicCNN EspañolCNN MexicoCNN FacebookCNN TwitterCNN Google+CNN HeroesImpact Your WorldCNN Freedom Project ISIS seizes key Iraqi city of Ramadi: What happens next? By Jethro Mullen and Yousuf Basil, CNN Updated 1205 GMT (1905 HKT) May 18, 2015 Source: CNN Story highlights "Anybody who supported the government will probably be executed within the next 24 hours," a security analyst says U.S. Secretary of State John Kerry says he's confident that ISIS gains will be reversed Iraq's Prime Minister says he's preparing to send reinforcements (CNN)Now that the key Iraqi city of Ramadi has fallen into the hands of ISIS militants, what happens next? It depends who you ask. Iraqi and U.S. officials are maintaining that the tide will soon turn back against ISIS, whose fighters seized control of Ramadi on Sunday after a prolonged offensive using explosive-laden bulldozers and other vehicles driven by suicide bombers. But many observers say that recovering from the loss of the strategic city -- the capital of Anbar province, Iraq's Sunni heartland -- will take a long time. "This is a huge setback to Iraqi forces and to the U.S. strategy to degrade and ultimately defeat ISIS," said Peter Mansoor, a CNN military analyst who was a colonel in the U.S. Army. The ISIS victory in Ramadi, after more than a year of fighting, shows the Sunni militant group's broader resilience in the face of sustained airstrikes from the U.S.-led coalition and pressure from Kurdish forces in the north. Backup forces bring their own challenges The Iraqi government says reinforcements for the security forces that pulled out of Anbar on Sunday are already on their way. Ramadi is just 110 kilometers (70 miles) west of Baghdad, the heavily fortified capital. But the nature of the forces believed to be heading to Anbar to take on ISIS there could present challenges. Iraqi Prime Minister Haider al-Abadi has ordered the Hashd Al-Shaabi paramilitary force -- also known as the Popular Mobilization Units -- to prepare for deployment. It will be joined by Iraqi security forces and Sunni tribal volunteers. The decision to mobilize the paramilitary force, which is Iranian-backed and predominantly Shiite, follows a request for help from Anbar provincial officials, tribal leaders and religious clerics. Concerns about role of Shiite forces The Shiite forces that are part of the Popular Mobilization Units helped the Iraqi army retake the city of Tikrit from ISIS in March. But their involvement prompted fears that it could inflame sectarian tensions, and their ties to Iran complicated the use of airstrikes by the U.S. coalition. Analyst: Iraq is a lost cause Analyst: Iraq is a lost cause 03:03 PLAY VIDEO Sending Shiite forces to fight ISIS in the heart of Sunni Iraq raised concerns among some observers. "That would be a different bloodbath on its own. It would be Sunni against Shia. Who knows what that would provoke?" said Robert Baer, a CNN intelligence and security analyst. Muhannad Haimour, a spokesman for the governor of Anbar, said the Popular Mobilization Units were no longer Shiite militias but an official body governed by law. "The governor made the position very clear that any Iraqi who wishes to defend Iraq is welcome to do so, provided that they are fighting under the Iraqi banner and under the command and control of the Iraqi official security forces," he told CNN. 'Hugely symbolic' city But the arrival of predominantly Shiite forces is likely to do little to soothe the grievances of the beleaguered Sunni tribes that have been fighting ISIS for control of Ramadi since the first half of last year. Officials in the city have repeatedly called for more support and weapons from the Shiite-dominated government in Baghdad and for more airstrikes by the U.S.-led coalition. But despite their warnings, one of the cities for which U.S. forces fought bitterly in 2005 and 2006 eventually fell to ISIS. "Ramadi is hugely symbolic," said Mansoor, a former aide to Gen. David Petraeus, who led U.S. forces in Iraq. "It's the birthplace of the Awakening, the tribal rebellion against al Qaeda in Iraq, the forerunner to ISIS -- a tribal rebellion that did so much to defeat that group back during the surge of 2007 and 2008." On Friday, the United States announced that it was "expediting" weapon shipments to Iraq because of the fighting in Ramadi. Speaking from Seoul, South Korea, on Monday, U.S. Secretary of State John Kerry said that "large numbers" of ISIS fighters had been killed in the past few days, and that more would be killed in the coming days "because that seems to be the only thing they understand." "It is possible to see the kind of attack we have in Ramadi, but I am absolutely confident in the days ahead that will be reversed," he said. Fears of 'bloodbath' under ISIS Now that the city is back in the hands of terrorists, officials are "extremely concerned about massacres that we think will be committed by ISIS," said Haimour, the Anbar governor's spokesman. "On the first day that ISIS took over the city, they executed a 3-year-old girl whose father was fighting against ISIS. And he later died in battle," he told CNN. ISIS has a grim track record of ruthlessly slaughtering opponents it captures. "Anybody who supported the government will probably be executed within the next 24 hours," said Baer. "Their families will be driven out. It will be a bloodbath over the next couple of days. All the soldiers who were captured will be executed." A flood of residents has been pouring out of Ramadi toward safer parts of Anbar and Baghdad in recent days. "We are witnessing a humanitarian crisis," said Haimour, estimating that as many as 8,000 people had left the city Sunday. As civilians fled, the heavy fighting continued. Officials estimate that more than 500 people have been killed in the most recent clashes in Ramadi, he said, noting that some pockets of resistance against ISIS remained inside the city. ISIS resilience, Iraqi difficulties Some analysts said ISIS' advances in Ramadi showed the extremist group's tenacity. "What's clear to me is ISIS is enduring and will continue to endure," said Baer. Others said the situation reflected long-standing issues with Iraqi security forces and Western efforts to strengthen them. "This is not about ISIS. This is about whether the Iraqi military has the capability and, more importantly, the will to face up with ISIS," he said. "They've had some successes, the military has. This is a setback. It's going to take years to figure out who will prevail." Baer said he thinks the fall of Ramadi rules out the likelihood of an Iraqi offensive this summer to kick ISIS out of Mosul, the northern city where government security forces fled from the militants last year. "I think Ramadi's probably lost for a long time, and other parts of Al-Anbar province, as well," he said. Haimour said it's unfair to portray Iraqi forces as unwilling to battle ISIS. Iraqi forces fought hard in Ramadi, he said, but faced well-trained ISIS fighters with heavy weaponry who were on a suicide mission. "They come to Anbar and Iraq to die. It's very difficult to stop a bulldozer that's been armored, driven by a suicide bomber, with tons of explosives," he said. "And dealing with these fighters has been extremely difficult. It's not a conventional war by any stretch of the imagination." CNN's Hamdi Alkhshali, Catherine Shoichet, Jomana Karadsheh and Tim Lister contributed to this report. Promoted Stories Why Nike Is The Problem, Not The Solution (TalkMarkets) When the Nazis Courted the KKK (OZY) Historic personal treasures from 1916 Rising… (IrishCentral) Emirates May Need Two Years To Respond… (Global Traveler Magazine) More From CNN Man buys dresser, finds treasure inside Jordan's King on how to defeat ISIS Alabama student marries ISIS fighter Kenya Moore's new 'boyfriend' is a married man Recommended by ISIS: Full coverage Birth certificate How ISIS controls life, from birth to foosball pkg damon isis advances_00000416.jpg ISIS loses quarter of territory in Iraq - 3 things to know ac dnt the rise of ISIS_00013008.jpg The Americans linked to ISIS Members of the Iraqi security forces leave Samarra, Iraq north of Baghdad, as they drive towards Tikrit, to launch an assault against the ISIS on February 28. ISIS releases some Christian hostages -- but why? Who's doing what in the coalition battle against ISIS lead dnt sciutto isis horrors organ harvesting report_00004410.jpg How ISIS makes (and takes) money Who has ISIS recruited from the West More from Asia Home of a soldier on Chigua Reef, Nansha Islands, Sansha City, Hainan Province. Chigua Reef one of the seven island reefs in the Nansha Islandsunder working control of the People's Republic of China, and the southernmost of these reefs. Zhang Zhuan, one of the soldiers guarding the reef, has completed 18 posts during his 16 years of navy service, with each post lasting three months. Stunning images show Chinese families and everything they own seoul buddhist kwon 1 Reunification the dream for South Korea's Buddhist patriarch lklv cnni nr karadsheh isis in ramadi_00000000 ISIS seizes control of key Iraqi city Ramadi as government forces pull back London, United KingdomClear12° News Regions Video TV Features Opinions More… © 2015 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved. Terms of service Privacy guidelines AdChoices Advertise with us About us Contact us Work for us Help Transcripts License Footage CNN Newsource News World Sport Technology Entertainment Style Travel Money Regions U.S. China Asia Middle East Africa Europe Americas Video Must Watch Videos Shows CNN en Español TV TV Shows Schedule Faces of CNN Worldwide Features Style Travel All Features Opinions iReport More… Photos Weather CNN Mobile Tools & Extras CNN Profiles A-Z CNN Leadership CNN Arabic CNN Español CNN Mexico CNN Facebook CNN Twitter CNN Google+ CNN Heroes Impact Your World CNN Freedom Project Quick Links Photos Weather CNN Mobile Tools & Extras CNN Profiles A-Z CNN Leadership CNN ArabicCNN EspañolCNN MexicoCNN FacebookCNN TwitterCNN Google+CNN HeroesImpact Your WorldCNN Freedom Project ISIS seizes key Iraqi city of Ramadi: What happens next? By Jethro Mullen and Yousuf Basil, CNN Updated 1205 GMT (1905 HKT) May 18, 2015 Source: CNN Story highlights "Anybody who supported the government will probably be executed within the next 24 hours," a security analyst says U.S. Secretary of State John Kerry says he's confident that ISIS gains will be reversed Iraq's Prime Minister says he's preparing to send reinforcements (CNN)Now that the key Iraqi city of Ramadi has fallen into the hands of ISIS militants, what happens next? It depends who you ask. Iraqi and U.S. officials are maintaining that the tide will soon turn back against ISIS, whose fighters seized control of Ramadi on Sunday after a prolonged offensive using explosive-laden bulldozers and other vehicles driven by suicide bombers. But many observers say that recovering from the loss of the strategic city -- the capital of Anbar province, Iraq's Sunni heartland -- will take a long time. "This is a huge setback to Iraqi forces and to the U.S. strategy to degrade and ultimately defeat ISIS," said Peter Mansoor, a CNN military analyst who was a colonel in the U.S. Army. The ISIS victory in Ramadi, after more than a year of fighting, shows the Sunni militant group's broader resilience in the face of sustained airstrikes from the U.S.-led coalition and pressure from Kurdish forces in the north. Backup forces bring their own challenges The Iraqi government says reinforcements for the security forces that pulled out of Anbar on Sunday are already on their way. Ramadi is just 110 kilometers (70 miles) west of Baghdad, the heavily fortified capital. The ISIS terror threat The ISIS terror threat 68 photos EXPAND GALLERY But the nature of the forces believed to be heading to Anbar to take on ISIS there could present challenges. Iraqi Prime Minister Haider al-Abadi has ordered the Hashd Al-Shaabi paramilitary force -- also known as the Popular Mobilization Units -- to prepare for deployment. It will be joined by Iraqi security forces and Sunni tribal volunteers. The decision to mobilize the paramilitary force, which is Iranian-backed and predominantly Shiite, follows a request for help from Anbar provincial officials, tribal leaders and religious clerics. Concerns about role of Shiite forces The Shiite forces that are part of the Popular Mobilization Units helped the Iraqi army retake the city of Tikrit from ISIS in March. But their involvement prompted fears that it could inflame sectarian tensions, and their ties to Iran complicated the use of airstrikes by the U.S. coalition. Analyst: Iraq is a lost cause Analyst: Iraq is a lost cause 03:03 PLAY VIDEO Sending Shiite forces to fight ISIS in the heart of Sunni Iraq raised concerns among some observers. "That would be a different bloodbath on its own. It would be Sunni against Shia. Who knows what that would provoke?" said Robert Baer, a CNN intelligence and security analyst. Muhannad Haimour, a spokesman for the governor of Anbar, said the Popular Mobilization Units were no longer Shiite militias but an official body governed by law. "The governor made the position very clear that any Iraqi who wishes to defend Iraq is welcome to do so, provided that they are fighting under the Iraqi banner and under the command and control of the Iraqi official security forces," he told CNN. 'Hugely symbolic' city But the arrival of predominantly Shiite forces is likely to do little to soothe the grievances of the beleaguered Sunni tribes that have been fighting ISIS for control of Ramadi since the first half of last year. Officials in the city have repeatedly called for more support and weapons from the Shiite-dominated government in Baghdad and for more airstrikes by the U.S.-led coalition. But despite their warnings, one of the cities for which U.S. forces fought bitterly in 2005 and 2006 eventually fell to ISIS. "Ramadi is hugely symbolic," said Mansoor, a former aide to Gen. David Petraeus, who led U.S. forces in Iraq. "It's the birthplace of the Awakening, the tribal rebellion against al Qaeda in Iraq, the forerunner to ISIS -- a tribal rebellion that did so much to defeat that group back during the surge of 2007 and 2008." On Friday, the United States announced that it was "expediting" weapon shipments to Iraq because of the fighting in Ramadi. Speaking from Seoul, South Korea, on Monday, U.S. Secretary of State John Kerry said that "large numbers" of ISIS fighters had been killed in the past few days, and that more would be killed in the coming days "because that seems to be the only thing they understand." "It is possible to see the kind of attack we have in Ramadi, but I am absolutely confident in the days ahead that will be reversed," he said. Fears of 'bloodbath' under ISIS Now that the city is back in the hands of terrorists, officials are "extremely concerned about massacres that we think will be committed by ISIS," said Haimour, the Anbar governor's spokesman. "On the first day that ISIS took over the city, they executed a 3-year-old girl whose father was fighting against ISIS. And he later died in battle," he told CNN. ISIS has a grim track record of ruthlessly slaughtering opponents it captures. "Anybody who supported the government will probably be executed within the next 24 hours," said Baer. "Their families will be driven out. It will be a bloodbath over the next couple of days. All the soldiers who were captured will be executed." A flood of residents has been pouring out of Ramadi toward safer parts of Anbar and Baghdad in recent days. "We are witnessing a humanitarian crisis," said Haimour, estimating that as many as 8,000 people had left the city Sunday. As civilians fled, the heavy fighting continued. Officials estimate that more than 500 people have been killed in the most recent clashes in Ramadi, he said, noting that some pockets of resistance against ISIS remained inside the city. ISIS resilience, Iraqi difficulties Some analysts said ISIS' advances in Ramadi showed the extremist group's tenacity. "What's clear to me is ISIS is enduring and will continue to endure," said Baer. Others said the situation reflected long-standing issues with Iraqi security forces and Western efforts to strengthen them. "This is not about ISIS. This is about whether the Iraqi military has the capability and, more importantly, the will to face up with ISIS," he said. "They've had some successes, the military has. This is a setback. It's going to take years to figure out who will prevail." Baer said he thinks the fall of Ramadi rules out the likelihood of an Iraqi offensive this summer to kick ISIS out of Mosul, the northern city where government security forces fled from the militants last year. "I think Ramadi's probably lost for a long time, and other parts of Al-Anbar province, as well," he said. Haimour said it's unfair to portray Iraqi forces as unwilling to battle ISIS. Iraqi forces fought hard in Ramadi, he said, but faced well-trained ISIS fighters with heavy weaponry who were on a suicide mission. "They come to Anbar and Iraq to die. It's very difficult to stop a bulldozer that's been armored, driven by a suicide bomber, with tons of explosives," he said. "And dealing with these fighters has been extremely difficult. It's not a conventional war by any stretch of the imagination." CNN's Hamdi Alkhshali, Catherine Shoichet, Jomana Karadsheh and Tim Lister contributed to this report. Promoted Stories Why Nike Is The Problem, Not The Solution (TalkMarkets) When the Nazis Courted the KKK (OZY) Historic personal treasures from 1916 Rising… (IrishCentral) Emirates May Need Two Years To Respond… (Global Traveler Magazine) More From CNN Man buys dresser, finds treasure inside Jordan's King on how to defeat ISIS Alabama student marries ISIS fighter Kenya Moore's new 'boyfriend' is a married man Recommended by ISIS: Full coverage Birth certificate How ISIS controls life, from birth to foosball pkg damon isis advances_00000416.jpg ISIS loses quarter of territory in Iraq - 3 things to know ac dnt the rise of ISIS_00013008.jpg The Americans linked to ISIS Members of the Iraqi security forces leave Samarra, Iraq north of Baghdad, as they drive towards Tikrit, to launch an assault against the ISIS on February 28. ISIS releases some Christian hostages -- but why? Who's doing what in the coalition battle against ISIS lead dnt sciutto isis horrors organ harvesting report_00004410.jpg How ISIS makes (and takes) money Who has ISIS recruited from the West More from Asia Home of a soldier on Chigua Reef, Nansha Islands, Sansha City, Hainan Province. Chigua Reef one of the seven island reefs in the Nansha Islandsunder working control of the People's Republic of China, and the southernmost of these reefs. Zhang Zhuan, one of the soldiers guarding the reef, has completed 18 posts during his 16 years of navy service, with each post lasting three months. Stunning images show Chinese families and everything they own seoul buddhist kwon 1 Reunification the dream for South Korea's Buddhist patriarch lklv cnni nr karadsheh isis in ramadi_00000000 ISIS seizes control of key Iraqi city Ramadi as government forces pull back London, United KingdomClear12° News Regions Video TV Features Opinions More… © 2015 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved. Terms of service Privacy guidelines AdChoices Advertise with us About us Contact us Work for us Help Transcripts License Footage CNN Newsource

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International Edition London, United Kingdom12° Sign in MyCNN News World Sport Technology Entertainment Style Travel Money Regions U.S. China Asia Middle East Africa Europe Americas Video Must Watch Videos Shows CNN en Español TV TV Shows Schedule Faces of CNN Worldwide Features Style Travel All Features Opinions iReport More… Photos Weather CNN Mobile Tools & Extras CNN Profiles A-Z CNN Leadership CNN Arabic CNN Español CNN Mexico CNN Facebook CNN Twitter CNN Google+ CNN Heroes Impact Your World CNN Freedom Project Quick Links Photos Weather CNN Mobile Tools & Extras CNN Profiles A-Z CNN Leadership CNN ArabicCNN EspañolCNN MexicoCNN FacebookCNN TwitterCNN Google+CNN HeroesImpact Your WorldCNN Freedom Project 'It will be a bloodbath' Fears of massacre after ISIS seizes key Iraqi city Officials are "extremely concerned" that ISIS will ruthlessly slaughter anyone in Ramadi who supported the government, says Anbar governor's spokesman. Sunni vs. Shia: What you need to know Analyst: Iraq is a lost cause ISIS commander killed in U.S. raid Top Stories Dean Potter highlines at the Three Gossips in Utah's Arches National Park. Unlike tightrope walking, highlighers must maintain their balance on a slack line instead of a taut one. Potter has completed a number of highline crossings without safety equipment. Climbing legend killed in BASE jump attempt FBI: Hacker 'controlled' plane's engine Marine dies in 'hard landing mishap' Senate hopeful sorry for race gaffe Prince Harry: Bring back UK military service Feds: No more military weapons for local cops Editor's Choice CC Sabathia of the New York Yankees throws against the Boston Red Sox in the first inning at Fenway Park May 1, 2015 in Boston, Massachusetts. Fat or fit? These 'obese' sports stars tip the scales 2017: The year flying cars take off? 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Chinese families display everything they own Stars of Tomorrow These museums of the future are mindblowing Featured Sections CNN Sport Messi marvelous as Barca made champs Lorenzo lights up Le Mans Djokovic wins Federer Roman duel Travel Anthony Bourdain in Madagascar for "Parts Unknown" The wilds of magnificent Madagascar Is this taking the Hello Kitty craze too far? 10 most scenic airport approaches Style Who designed this very kitsch bar? 41 radical new Chinese designers Classic cars that made history Money Gucci sues Alibaba over fakes (again) Tim Cook: How Steve Jobs changed the world Economic storm ahead? El Nino is back Technology Internet captivated by 98 cubes of raw food Inside China's start-up city Electronic skin may transform your body Defining Moments MELBOURNE, AUSTRALIA - MAY 18: Lovers padlocks are seen fastened to the Southgate footbridge on May 18, 2015 in Melbourne, Australia. Melbourne city council will remove over 20,000 locks from the bridge this week over concerns for safety. (Photo by Pat Scala/Getty Images) Breaking the chain of love Video pkg elbagir isis threaten palmyra_00020624.jpg Ancient Syrian city of Palmyra threatened by ISIS The UNESCO world heritage site of Palmyra is an archeological gem that has been threatened by the advance of ISIS. CNN's Nima Elbagir reports. pkg wedeman migrants milk kindness_00001312.jpg Illegal migration to Italy on the rise pkg mclaughlin amtrak train derailment_00000921.jpg Investigators looking at marking on Amtrak 188 train Cpl. Mackenzie Higgins guides a UH-1Y Huey for takeoff at the Tribhuvan International Airport in Kathmandu, Nepal, May 5. Families grieve Marines killed in Nepal crash pkg curry cannes uber helicopter_00011203.jpg Uber test-flies 'Uberchopper' at Cannes Tawny Willoughby used a tanning bed 4 to 5 times a week in high school. Now, at 27, she's dealing with painful skin-cancer treatments. Woman posts skin cancer selfies as warning for tanners Dean Potter highlines at the Three Gossips in Utah's Arches National Park. Unlike tightrope walking, highlighers must maintain their balance on a slack line instead of a taut one. Potter has completed a number of highline crossings without safety equipment. Extreme sports legend and friend killed in base jump FRD-DS-00253 Film Name: MAD MAX: FURY ROAD Copyright: © 2014 WV FILMS IV LLC AND RATPAC-DUNE ENTERTAINMENT LLC - U.S., CANADA, BAHAMAS & BERMUDA © 2014 VILLAGE ROADSHOW FILMS (BVI) LIMITED - ALL OTHER TERRITORIES Photo Credit: Jasin Boland Caption: A scene from Warner Bros. Pictures' and Village Roadshow Pictures' action adventure "MAD MAX: FURY ROAD," a Warner Bros. Pictures release. 'Mad Max' director: 'There's no green screen or CG' pkg liebermann mideast palestinian sainthood _00002008.jpg Sainthood for Palestinian nuns pkg Antarctic ice shelf to disintegrate_00000000.jpg NASA: Antarctic ice shelf will disintegrate Ship-related debris on the sea floor, including an anchor MH370 search discovers uncharted shipwreck screen-free week lisas desk orig mg_00002822.jpg After 2 days of screen-free life, addict does this Regions U.S. Bikers wait in a line as law enforcement officers investigate the shooting. 9 dead in Texas biker gang shootout Asia seoul buddhist kwon 13 N. Korea: Are prayers the answer? Latin America Mexican authorities say they rescued a group of Cuban migrants on a raft off the country's Yucatan Peninsula on May 17, 2015. Cuban migrants rescued off Mexican coast Europe lok nadeau vatican pope saints_00005103.jpg Pope confers sainthood on two Palestinians Africa A man is lifted by police during a protest in Bujumbura on May 13, 2015. 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World in photos Louvre Top 20 museums around the world Opinions Opinions Obama, Arab nations dance to different tunes Tsarnaev sentence traps us in cycle of violence Can amnesia be a defense in court? Latest FRD-DS-00253 Film Name: MAD MAX: FURY ROAD Copyright: © 2014 WV FILMS IV LLC AND RATPAC-DUNE ENTERTAINMENT LLC - U.S., CANADA, BAHAMAS & BERMUDA © 2014 VILLAGE ROADSHOW FILMS (BVI) LIMITED - ALL OTHER TERRITORIES Photo Credit: Jasin Boland Caption: A scene from Warner Bros. Pictures' and Village Roadshow Pictures' action adventure "MAD MAX: FURY ROAD," a Warner Bros. Pictures release. 'Mad Max: Fury Road' driving critics wild Kim Jong Un: Effective tyrant or panicking? Obama, Arab nations dance to different tunes iReport Hager and her son, Brady, who his mom credits in her recovery. How a coma made me a happier person Kids meeting their baby siblings Quadruple rainbow awes Internet In Case You Missed It London, United KingdomClear12° News Regions Video TV Features Opinions More… © 2015 Cable News Network. Turner Broadcasting System, Inc. All Rights Reserved. Terms of service Privacy guidelines AdChoices Advertise with us About us Contact us Work for us Help Transcripts License Footage CNN Newsource