4,105 research outputs found

    Toxicological Effects of Commercial Sunscreens on Coral Reef Ecosystems: New Protocols for Coral Restoration

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    The primary purpose of consumer-grade sunscreen is to protect skin from harmful UVA and UVB rays. This market has grown during the past 80 years, and environmental contamination from increasing amounts of sunscreen compounds have created concern. In particular, impacts on ocean ecosystems have inspired investigations and toxicological research on their effects on marine life. Unfortunately, such studies using marine flora and fauna are scarce, and the impact of chemical exposure to consumer sunscreens is neither adequately measured nor completely understood. In a pilot study by the Coral Restoration Foundation, in situ toxicity exposure to 10 different brands of sunscreens was performed on the Caribbean scleractinian staghorn coral, Acropora cervicornis. Coral samples were ranked on tissue degradation following the sunscreen exposure, however no significant differences were found between exposed and control samples. Additional studies should be performed to better understand other possible sub-lethal effects. One such application is in the proper handling of corals during restoration; as other compelling evidence indicates, sunscreens have the potential to be toxic depending on concentration and exposure time, among other factors. This literature review revealed that sunscreens containing only non-nano zinc oxide or non-nano titanium dioxide as primary UV filters may best reduce stress to marine organisms and coral fragments in coral nurseries

    A Dispersive Treatment of K4K_{\ell4} Decays

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    K4K_{\ell4} are for several reasons an especially interesting decay channel of KK mesons: K4K_{\ell4} decays allow an accurate measurement of a combination of SS-wave ππ\pi\pi scattering lengths, one form factor of the decay is connected to the chiral anomaly and the decay is the best source for the determination of some low energy constants of ChPT. We present a dispersive approach to K4K_{\ell4} decays, which takes rescattering effects fully into account. Some fits to NA48/2 and E865 measurements and results of the matching to ChPT are shown.Comment: 4 pages, talk given by PS at MESON2012 - 12th International Workshop on Meson Production, Properties and Interaction, Krak\'ow, Poland, 31 May - 5 June 201

    Clogging by sieving in microchannels: Application to the detection of contaminants in colloidal suspensions

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    We report on a microfluidic method that allows measurement of a small concentration of large contaminants in suspensions of solid micrometer-scale particles. To perform the measurement, we flow the colloidal suspension through a series of constrictions, i.e. a microchannel of varying cross-section. We show and quantify the role of large contaminants in the formation of clogs at a constriction and the growth of the resulting filter cake. By measuring the time interval between two clogging events in an array of parallel microchannels, we are able to estimate the concentration of contaminants whose size is selected by the geometry of the microfluidic device. This technique for characterizing colloidal suspensions offers a versatile and rapid tool to explore the role of contaminants on the properties of the suspensions

    Regulation, SME Performance and Growth in Cameroon's Manufacturing and Retail Sectors

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    Research into small business activity has grown impressively over the last decade, though studies on the impact of regulation on business performance remains relatively under-explored. SMEs in Africa face difficulties in infrastructure, finance, as well as in complying with regulations and other governmental requirements. Confronted with poor economic performance, Cameroon began looking at policies to improve SMEs performance and to promote economic growth. This study hence examined the impact of regulation on SMEs performance and growth in Cameroon. The Tax department and the Municipality are the most well-known regulators. Businesses that are aware of their status as SMEs also legally register their companies. However, regulatory compliance of SMEs is low. Therefore the study recommends the establishment of one-stop shop for SMEs registration in Cameroon

    Magnetic order in the frustrated Ising-like chain compound Sr3_3NiIrO6_6

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    We have studied the field and temperature dependence of the magnetization of single crystals of Sr3NiIrO6. These measurements evidence the presence of an easy axis of anisotropy and two anomalies in the magnetic susceptibility. Neutron powder diffraction realized on a polycrystalline sample reveals the emergence of magnetic reflections below 75 K with magnetic propagation vector k ~ (0, 0, 1), undetected in previous neutron studies [T.N. Nguyen and H.-C zur Loye, J. Solid State Chem., 117, 300 (1995)]. The nature of the magnetic ground state, and the presence of two anomalies common to this family of material, are discussed on the basis of the results obtained by neutron diffraction, magnetization measurements, and symmetry arguments

    Long-chain n-3 fatty acids as an essential link between musculoskeletal and cardio-metabolic health in older adults

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    This narrative review aims to critically evaluate scientific evidence exploring the therapeutic role(s) of long-chain n-3 PUFA in the context of ageing, and specifically, sarcopenia. We highlight that beyond impairments in physical function and a lack of independence, the age-related decline in muscle mass has ramifications for cardio-metabolic health. Specifically, skeletal muscle is crucial in regulating blood glucose homeostasis (and by extension reducing type 2 diabetes mellitus risk) and providing gluconeogenic precursors that are critical for survival during muscle wasting conditions (i.e. AIDS). Recent interest in the potential anabolic action of n-3 PUFA is based on findings from experimental studies that measured acute changes in the stimulation of muscle protein synthesis (MPS) and/or chronic changes in muscle mass and strength in response to fish oil-derived n-3 PUFA supplementation. Key findings include a potentiated response of MPS to amino acid provision or resistance-based exercise with n-3 PUFA in healthy older adults that extrapolated to longer-term changes in muscle mass and strength. The key mechanism(s) underpinning this enhanced response of MPS remains to be fully elucidated, but is likely driven by the incorporation of exogenous n-3 PUFA into the muscle phospholipid membrane and subsequent up-regulation of cell signalling proteins known to control MPS. In conclusion, multiple lines of evidence suggest that dietary n-3 PUFA provide an essential link between musculoskeletal and cardio-metabolic health in older adults. Given that western diets are typically meagre in n-3 PUFA content, nutritional recommendations for maintaining muscle health with advancing age should place greater emphasis on dietary n-3 PUFA intake

    Do Analysts Add Value When They Most Can? Evidence From Corporate Spin-Offs

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    This article investigates how securities analysts help investors understand the value of diversification. By studying the research that analysts produce about companies that have announced corporate spin-offs, we gain unique insights into how analysts portray diversified firms to the investment community. We find that while analysts\u27 research about these companies is associated with improved forecast accuracy, the value of their research about the spun-off subsidiaries is more limited. For both diversified firms and their spun-off subsidiaries, analysts\u27 research is more valuable when information asymmetry between the management of these entities and investors is higher. These findings contribute to the corporate strategy literature by shedding light on the roots of the diversification discount and by showing how analysts\u27 research enables investors to overcome asymmetric information
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