On the Quantum Theory of Massless Spin-3/2 Field in Minkowski Spacetime

From the modern viewpoint and by the geometric method, this paper provides a concise foundation for the quantum theory of massless spin-3/2 field in Minkowski spacetime, which includes both the one-particle's quantum mechanics and the many-particle's quantum field theory. The explicit result presented here is useful for the investigation of spin-3/2 field in various circumstances such as supergravity, twistor programme, Casimir effect, and quantum inequality.Comment: 11 pages, typos corrected, accepted for publication in Int.J.Geom. Methods Mod. Phy

Strong enhancement of chlorophyll a concentration by a weak typhoon

Recent studies demonstrate that chlorophyll a (chl a) concentrations in the surface ocean can be significantly enhanced due to typhoons. The present study investigated chl a concentrations in the middle of the South China Sea (SCS) from 1997-2007. Only the Category1 (minimal) Typhoon Hagibis (2007) had a notable effect on the chl a concentrations. Typhoon Hagibis had a strong upwelling potential due to its location near the equator, and the forcing time of the typhoon (>82 h) was much longer than the geostrophic adjustment time (~63 h). The higher upwelling velocity and the longer forcing time increased the depth of the mixed-layer, which consequently induced a strong phytoplankton bloom that accounted for about 30% of the total annual chl a concentration in the middle of the SCS. The implication is that the forcing time of a typhoon should be long enough to establish a strong upwelling and consequently for the induction of significant upper ocean responses.Comment: Typhoon-Ocean Environment interaction

Perceived Stress and Cognitive Functions among Chinese Older Adults: The Moderating Role of Health Status

Objective: The primary purposes of the present study are 1) to investigate the stress-cognition relationship among U.S. Chinese older adults; and 2) to examine the moderating role of health status on the stress-cognition relationship. Method: Data were drawn from the Population Study of Chinese Elderly in Chicago (PINE), which investigated 3,159 Chinese adults over 60 years old living in Chicago. Participants reported health status and completed the Chinese Perceived Stress Scale. Cognitive functions were measured by the East Boston Memory Test, the Digit Span Backwards, the Symbol Digit Modalities Test, and Chinese Mini-Mental State Examination. Results: Controlling for age, sex, education, and income, perceived stress was negatively associated with cognitive functions, whereas health status was positively associated with cognitive functions. In addition, older adults’ health status interacted with stress such that the negative relationships between perceived stress and cognitive functions were more pronounced for those who had poor health than for those who had good health. Conclusion: Findings suggest that physical health is a critical factor moderating the relationship between perceived stress and cognitive functions among U.S. Chinese older adults. Longitudinal research is needed to examine the complex relationships among stress, health, and cognitive functions of U.S. Chinese older adults

Research on bearing radiation noise and optimization design based on coupled vibro-acoustic method

For bearings, radiation noise was an important evaluation index for mechanical property, in particularly mute machinery. Environmental pollution caused by bearing noise has always been the focus in bearing industry. In this paper, slippage of the rolling bearing and its own variable stiffness excitation were considered to accomplish the vibration coupling between the bearing and bearing seat as well as the coupling between bearing vibration and noise by means of combination of dynamic model, FEA model and boundary element method. A perfect coupled vibro-acoustic model of the bearing was built, and its results were compared with the experimental results to verify the reliability of the proposed method. Based on the verified simulation model, the improved design was carried out for the low-noise rolling bearings. Finally, in order to further verify the superiority of the proposed method in this paper, the designed rolling bearing was compared with that of the traditional design method. The results showed that the proposed design method was reliable

Hydrogen Generation from Al-NiCl2/NaBH4 Mixture Affected by Lanthanum Metal

The effect of La on Al/NaBH4 hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl2/NaBH4 mixture (Al-15 wt% La-5 wt% NiCl2/NaBH4 weight ratio, 1 : 3) has 126 mL g−1 min−1 maximum hydrogen generation rate and 1764 mL g−1 hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl2, La has great effect on NaBH4 hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl2 in the milling process, which induces that the hydrolysis byproduct Ni2B is highly distributed into Al(OH)3 and the catalytic reactivity of Ni2B/Al(OH)3 is increased therefore. But hydrolysis byproduct La(OH)3 deposits on Al surface and leads to some side effect. The Al-La-NiCl2/NaBH4 mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material

Altered microRNA expression in patients with non-obstructive azoospermia

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), a class of small non-coding RNA molecules, are indicated to play essential roles in spermatogenesis. However, little is known about the expression patterns or function of miRNAs in human testes involved in infertility.</p> <p>Methods</p> <p>In this study, the miRNA expression profiles of testes of patients with non-obstructive azoospermia (NOA) and normal controls were performed by using microarray technologies.</p> <p>Results</p> <p>Altered microRNA expression in NOA patients was found, with 154 differentially down-regulated and 19 up-regulated miRNAs. These findings have been confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR) assays on select miRNAs, including miR-302a, miR-491-3p, miR-520d-3p and miR-383. Several down-regulated miRNA clusters in patients with NOA were identified, such as the oncogenic potential of the mir-17-92 cluster and mir-371,2,3 cluster.</p> <p>Conclusion</p> <p>This is the first report that the expression of miRNAs is altered in testicular tissues of patients with NOA, suggesting a role of miRNAs in regulating spermatogenesis in human males.</p