8,712 research outputs found
The Three-Loop Free Energy for High-Temperature QED and QCD with Fermions
We compute the free energy density for gauge theories, with fermions, at high
temperature and zero chemical potential. Specifically, we analytically compute
the free energy through , which requires the evaluation of three-loop
diagrams. This computation extends our previous result for pure gauge QCD.Comment: 26 pages, 9 postscript figures, UW/PT-94-1
Switchable opening and closing of a liquid marble via ultrasonic levitation
Liquid marbles have promising applications in the field of microreactors, where the opening and closing of their surfaces plays a central role. We have levitated liquid water marbles using an acoustic levitator and, thereby, achieved the manipulation of the particle shell in a controlled manner. Upon increasing the sound intensity, the stable levitated liquid marble changes from a quasi-sphere to a flattened ellipsoid. Interestingly, a cavity on the particle shell can be produced on the polar areas, which can be completely healed when decreasing the sound intensity, allowing it to serve as a microreactor. The integral of the acoustic radiation pressure on the part of the particle surface protruding into air is responsible for particle migration from the center of the liquid marble to the edge. Our results demonstrate that the opening and closing of the liquid marble particle shell can be conveniently achieved via acoustic levitation, opening up a new possibility to manipulate liquid marbles coated with non-ferromagnetic particles
Nodal Spin Density Wave and band topology of the FeAs based materials
The recently discovered FeAs-based materials exhibit a Spin Density
Wave (SDW) in the undoped state, which gives way to superconductivity upon
doping. Here we show that due to an interesting topological feature of the band
structure, the SDW state cannot acquire a full gap. This is demonstrated within
the SDW mean-field theory of both a simplified two band model and a more
realistic 5-band model. The positions of the nodes are different in the two
models and can be used to detected the validity of each model.Comment: rewritten for clarit
Abdominal obesity and the prevalence of diabetes and intermediate hyperglycaemia in Chinese adults
Objective: To assess the association of indicators of general and abdominal obesity with the prevalence of type 2 diabetes (T2DM) and intermediate hyperglycaemia (IHG) in the Chinese population. Methods: We used data of 50 905 adults aged 18¿79 years in the 2002 China National Nutrition and Health Survey. Recommended Chinese cut-off values were used for BMI (24 kg/m2) and waist circumference (WC; 85 cm in men, 80 cm in women). Optimal cut-offs for waist:height ratio (WHtR) were determined from analyses of receiver-operating characteristic (ROC) curves. Results: The prevalence of T2DM and IHG was 2?6% and 1?9% respectively. ROC curve analyses indicated 0?5 as the optimal cut-off value for WHtR in both sexes. High BMI, WC and WHtR were all associated with the prevalence of glucose tolerance abnormalities, with the highest prevalence ratio (PR) for high WHtR (men: PR52?85, 95% CI 2?54, 3?21; women: PR53?10, 95% CI 2?74, 3?51). When combining BMI and WHtR, in men either a high BMI or a high WHtR alone was associated with increased risk. Among women, a high BMI without a concomitant high WHtR was not associated with increased glucose tolerance abnormalities risk, whereas a high WHtR was associated with risk irrespective of BMI. Conclusions: Among the Chinese adult population measures of central obesity are better predictors of glucose tolerance abnormalities prevalence than BMI. AWHtR cutoff point of 0?5 for both men and women can be considered as optimum for predicting (pre-) diabetes and may be a useful tool for screening and health education
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