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A team of international occupational health and safety professionals evaluated the working conditions and health status of miners at a giant open-pit copper mine in Cananea, Mexico. Workers in the ore processing plants were expose...
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A team of international occupational health and safety professionals evaluated the working conditions and health status of miners at a giant open-pit copper mine in Cananea, Mexico. Workers in the ore processing plants were exposed to levels of crystalline silica 10 times the Mexican regulatory limit, high levels of acid mist and noise, and numerous safety hazards, including unguarded machinery and malfunctioning 10- and 15-ton cranes. Lung function testing and interviews with physicians showed a substantial percentage of miners with adverse respiratory symptoms including shortness of breath (46%), wheezing (12%), coughing (12%), and elevated sputum production (10%). The mine owner, Grupo Mexico, violated Mexican law by failing to conduct an industrial hygiene survey sufficient to identify, evaluate, and control health hazards including exposure to mineral dust (including silica), acid mists, airborne solvents, high noise levels, high vibration levels, and extreme temperatures.
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CoMnSi and CoMnSi_(1-x)Ge_x have recently been shown to exhibit negative magnetocaloric properties at a first-order magnetic-field-driven metamagnetic phase transition between a low-temperature antiferromagnetic phase and a high-t...
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CoMnSi and CoMnSi_(1-x)Ge_x have recently been shown to exhibit negative magnetocaloric properties at a first-order magnetic-field-driven metamagnetic phase transition between a low-temperature antiferromagnetic phase and a high-temperature ferromagnetic phase. We find that doping with Fe changes the magnetocaloric properties drastically by (a) lowering the metamagnetic transition temperature and field, (b) yielding a higher magnetocaloric effect at lower fields than in CoMnSi, and (c) producing an unusual downturn in the entropy change in the highest fields measured. We also find that fragmentation of the sample lowers the transition field reflecting the role of strain in these samples but makes no significant change to the hysteresis loss or the entropy change.
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In recent years much debate has focused on the practice of continuous deep sedation until death and its acceptability on an ethical level. While many view its performance as part of normal medical practice, provided that particula...
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In recent years much debate has focused on the practice of continuous deep sedation until death and its acceptability on an ethical level. While many view its performance as part of normal medical practice, provided that particular safeguards are met, it is also believed to be a covert form of euthanasia in some cases
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Stimulated emission (SE) in the blue-green (480 nm) and green (514 nm) regime has been observed, at room temperature (RT) under optical pumping, from nonpolar m-plane (1010) and semipolar (1122) InGaN multi-quantum well (MQW) lase...
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Stimulated emission (SE) in the blue-green (480 nm) and green (514 nm) regime has been observed, at room temperature (RT) under optical pumping, from nonpolar m-plane (1010) and semipolar (1122) InGaN multi-quantum well (MQW) laser diode (LD) structures, respectively, grown on bulk GaN substrates. The emission intensity exhibited a clear threshold behavior with respect to the pump power. Optical anisotropy was also observed between the two perpendicular in-plane directions [1123] and [1010] for semipolar LD structures, with significantly lower pump thresholds for emission along [1123]. The SE wavelength, measured just above threshold, was blue-shifted with respect to the spontaneous emission wavelength measured just below threshold. These initial results indicate that semipolar (1122) GaN is a promising orientation for the realization of blue-green and green LDs.
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