1,675 research outputs found
1998 Superoutburst of the Large-Amplitude SU UMa-Type Dwarf Nova WX Ceti
We observed the 1998 November superoutburst of WX Cet, a dwarf nova
originally proposed as a WZ Sge-like system. The observation established that
WX Cet is an SU UMa-type dwarf nova with a mean superhump period of 0.05949(1)
d, which is 2.1% longer than the reported orbital period. The lack of early
superhumps at the earliest stage of the superoutburst, the rapid development of
usual superhumps, and the possible rapid decay of late superhumps seem to
support that WX Cet is a fairly normal large-amplitude SU UMa-type dwarf nova,
rather than a WZ Sge-type dwarf nova with a number of peculiarities. However, a
period increase of superhumps at a rate dot(P)/P = (+8.5+/-1.0) x 10^-5 was
observed, which is one of the largest dot(P)/P ever observed in SU UMa-type
dwarf novae. A linear decline of light, with a rate of 0.10 mag/d, was observed
in the post-superoutburst stage. This may be an exemplification of the decay of
the viscosity in the accretion disk after the termination of a superoutburst,
mechanism of which is proposed to explain a variety of post-superoutburst
phenomena in some SU UMa-type dwarf novae.Comment: 8 pages, 8 figures, accepted for publication in Publ. Astron. Soc.
Japa
Postprandial endothelial dysfunction in subjects with new-onset type 2 diabetes: an acarbose and nateglinide comparative study
<p>Abstract</p> <p>Background</p> <p>Postprandial hyperglycemia is believed to affect vascular endothelial function. The aim of our study was to compare the effects of acarbose and nateglinide on postprandial endothelial dysfunction.</p> <p>Methods</p> <p>We recruited a total of 30 patients with newly diagnosed type 2 diabetes (19 men and 11 women, age 67.8 ± 7.3 years). Patients were randomly assigned to 3 groups receiving either 300 mg/day acarbose, 270 mg/day nateglinide, or no medication. A cookie test (consisting of 75 g carbohydrate, 25 g butter fat, and 7 g protein for a total of 553 kcal) was performed as dietary tolerance testing. During the cookie test, glucose and insulin levels were determined at 0, 30, 60, and 120 min after load. In addition, endothelial function was assessed by % flow-mediated dilation (FMD) of the brachial artery at 0 and 120 min after cookie load.</p> <p>Results</p> <p>Postprandial glucose and insulin levels were similar in the 3 groups. Postprandial endothelial dysfunction was similar in the 3 groups before treatment. After 12 weeks of intervention, postprandial FMD was significantly improved in the acarbose group compared with the control group (6.8 ± 1.3% vs 5.2 ± 1.1%, p = 0.0022). Area under the curve (AUC) for insulin response was significantly increased in the nateglinide and control groups; however, no significant change was observed in the acarbose group.</p> <p>Conclusions</p> <p>Our results suggest that acarbose improves postprandial endothelial function by improvement of postprandial hyperglycemia, independent of postprandial hyperinsulinemia. Acarbose may thus have more beneficial effects on postprandial endothelial function in patients with type 2 diabetes than nateglinide.</p
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A novel magnetic resonance imaging postprocessing technique for the assessment of intervertebral disc degeneration-Correlation with histological grading in a rabbit disc degeneration model.
Introduction:Estimation of intervertebral disc degeneration on magnetic resonance imaging (MRI) is challenging. Qualitative schemes used in clinical practice correlate poorly with pain and quantitative techniques have not entered widespread clinical use. Methods:As part of a prior study, 25 New Zealand white rabbits underwent annular puncture to induce disc degeneration in 50 noncontiguous lumbar discs. At 16 weeks, the animals underwent multi-echo T2 MRI scanning and were euthanized. The discs were stained and examined histologically. Quantitative T2 relaxation maps were prepared using the nonlinear least squares method. Decay Variance maps were created using a novel technique of aggregating the deviation in the intensity of each echo signal from the expected intensity based on the previous rate of decay. Results:Decay Variance maps showed a clear and well demarcated nucleus pulposus with a consistent rate of decay (low Decay Variance) in healthy discs that showed progressively more variable decay (higher Decay Variance) with increasing degeneration. Decay Variance maps required significantly less time to generate (1.0 ± 0.0 second) compared with traditional T2 relaxometry maps (5 (±0.9) to 1788.9 (±116) seconds). Histology scores correlated strongly with Decay Variance scores (r = 0.82, P < .01) and weakly with T2 signal intensity (r = 0.32, P < .01) and quantitative T2 relaxometry (r = 0.39, P < .01). Decay Variance had superior sensitivity and specificity for the detection of degenerate discs when compared to T2 signal intensity or Quantitative T2 mapping. Conclusion:Our results show that using a multi-echo T2 MRI sequence, Decay Variance can quantitatively assess disc degeneration more accurately and with less image-processing time than quantitative T2 relaxometry in a rabbit disc puncture model. The technique is a viable candidate for quantitative assessment of disc degeneration on MRI scans. Further validation on human subjects is needed
Visualizing chromosome structure/organization
With the rapid development of sequencing technologies in the past decade, many eukaryotic genomes have been resolved at the primary sequence level. However, organization of the genome within nuclei and the principles that govern such properties remain largely unclear. Optimization of fluorescence probe-based hybridization technologies combined with new advances in the instrumentation for microscopy has steadily yielded more structural information on chromosome organization in eukaryote model systems. These studies provide static snapshots of the detailed organization of chromatin. More recently, the successful application of a chromatin tagging strategy utilizing auto fluorescent fusion proteins opened a new era of chromatin studies in which the dynamic organization of the genome can be tracked in near real time. This review focuses on these new approaches to studying chromatin organization and dynamics in plants, and on future prospects in unraveling the basic principle of chromosome organization
Japan-China academic exchange in nanomedicine
中国語:日中纳米医学的交流 p.6
Evaluating compulsory voting: Australia in comparative perspective.
Low turnout is a growing concern among the industrial democracies. Compulsory voting has achieved very high turnouts in several countries, but it has been mostly neglected as a solution to the problem of low turnout elsewhere. This thesis considers the usefulness of compulsory voting for industrial democracies. I argue that, for it to be useful, compulsory voting must be effective on two levels. First, compulsory voting must be effective in increasing turnout. Second, the high turnout resulting from compulsory voting must improve the total utility of the people-defined here as the well-being of the people-otherwise compulsory voting will not ultimately be useful. Rational choice models are constructed and operationalised in order to describe, explain and evaluate compulsory voting. Although data analysis is undertaken for a range of industrial democracies in order to test these rational choice hypotheses, the major focus of this research is on Australia, which has achieved very high turnout levels (around 95% of the registered voters) since the introduction of compulsory voting for federal elections in 1924. Furthermore, by examining the case of Australia, this thesis determines the conditions and necessary adjustments for compulsory voting to work effectively in practice. Finally, compulsory voting is tested with rational choice theory and data analysis on the actual industrial democracies in order to see whether this system is applicable under globally varying conditions. The conclusion of the analysis is that compulsory voting seems to be useful for several industrial democracies in theory and also seems to be workable in practice. However, some subjective judgement needs to be introduced for a full cost-benefit analysis to be made about compulsory voting
Particle Swarm Optimization Combining Diversification and Intensification for Nonlinear Integer Programming Problems
In this research, focusing on nonlinear integer programming
problems, we propose an approximate solution method
based on particle swarm optimization proposed by Kennedy
et al. And we developed a new particle swarm optimization
method which is applicable to discrete optimization problems
by incoporating a new method for generating initial search
points, the rounding of values obtained by the move scheme
and the revision of move methods. Furthermore, we showed the
efficiency of the proposed particle swarm optimization method by comparing it with an existing method through the application of them into the numerical examples. Moreover we expanded revised particle swarm optimization method for application to nonlinear integer programming problems and showed more effeciency than genetic algorithm. However, variance of the solutions obtained by the PSO method is large and accuracy is not so high. Thus, we consider improvement of accuracy introducing diversification and intensification
Ejecta Size Distribution Resulting from Hypervelocity Impact of Spherical Projectiles on CFRP Laminates
AbstractThe size distributions of ejecta resulting from projectile perforation of CFRP (carbon fiber reinforced plastic) laminates were examined. The shape of the ejecta cone and the debris cloud was observed using a high-speed video camera. The ejecta fragments were collected from the test chamber after impact experiments. The number of fragments ejected on the front side of the target was altered by the impact velocity. Conversely, regardless of impact velocity, the number of fragments ejected on the rear side of the target was almost the same.The results were also compared with the results of NASA's breakup model. The slope on the cumulative number distribution curve of characteristic length, LC, was almost the same as that of NASA's breakup model. The area-to-mass ratio distribution of ejecta fragments from CFRP laminates ranged within and above the area surrounded by ±3σ of NASA's breakup model
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