A High Flux Source of Cold Rubidium

We report the production of a continuous, slow, and cold beam of 87-Rb atoms with an unprecedented flux of 3.2 x 10^12 atoms/s and a temperature of a few milliKelvin. Hot atoms are emitted from a Rb candlestick atomic beam source and transversely cooled and collimated by a 20 cm long atomic collimator section, augmenting overall beam flux by a factor of 50. The atomic beam is then decelerated and longitudinally cooled by Zeeman slowing

Exclusive Radiative Decays of Upsilon in SCET

We study exclusive radiative decays of the $\Upsilon$ using soft-collinear effective theory and non-relativistic QCD. In contrast to inclusive radiative decays at the endpoint we find that color-octet contributions are power suppressed in exclusive decays, and can safely be neglected, greatly simplifying the analysis. We determine the complete set of Lorentz structures that can appear in the SCET Wilson coefficients and match onto them using results from a previous calculation. We run these coefficients from the scale \mups to the scale $\Lambda \sim 1 \textrm{GeV}$, thereby summing large logarithms. Finally we use our results to predict the ratio of branching fractions $B(\Upsilon \to \gamma f_2)/B(J/\psi \to \gamma f_2)$, $B(J/\psi \to \gamma f_2)/B(\psi' \to \gamma f_2)$, and the partial rate for $\Upsilon \to \gamma \pi \pi$.Comment: 17 pages, 2 figures. Updated to reflect published versio

Nitrous oxide-induced motor-predominant axonal peripheral neuropathy: A phenotype distinct from isolated vitamin B12 deficiency

Highlights: N2O toxicity and B12 deficiency both cause a sensory predominant myeloneuropathy. N2O abuse may also lead to a selectively severe motor axonal peripheral neuropathy. This motor neuropathy phenotype may be related to N2O direct neural toxicity. In-vivo measures of motor axonal dysfunction are more pronounced in N2O abuse

Expression of TGF-β1 and β3 but not apoptosis factors relates to flow-induced aortic enlargement

BACKGROUND: Cell proliferation and apoptosis are both involved in arterial wall remodeling. Increase in blood flow induces arterial enlargement. The molecular basis of flow-induced remodeling in large elastic arteries is largely unknown. METHODS: An aortocaval fistula (ACF) model in rats was used to induce enlargement in the abdominal aorta. Aortic gene expression of transforming growth factors beta (TGF-β) and apoptosis-related factors was assessed at 1 and 3 days and 1, 2, 4, and 8 weeks. Expression levels were determined using a ribonuclease protection assay and western blotting. Cell proliferation and apoptosis were analyzed using BrdU incorporation and TUNEL techniques. RESULTS: Blood flow increased 5-fold immediately after ACF (P<0.05). Lumen diameter of the aorta was 30% and 75% larger at 2 and 8 weeks respectively than those of controls (P<0.05). mRNA levels of TGF-β1 and TGF-β3 increased after ACF, peaked at 3 days (P<0.05) and returned to normal level at 1 week and thereafter. Western blotting showed enhanced expression of TGF-β1 at 3 days and TGF-β3 at 1 and 3 days and 1 week (P<0.05). mRNA levels of Bcl-xS initially decreased at 1 day, 3 days and 1 week, followed a return to baseline level at 2 weeks. Cell proliferation was observed at all time points after ACF (P<0.001 vs. controls) with proliferation in endothelial cells more significant than smooth muscle cells. Apoptosis was not significant. CONCLUSIONS: Gene expression of TGF-β1 and β3 precedes arterial enlargement. Expression of apoptosis related factors is little regulated in the early stage of the flow-induced arterial remodeling

Event-Free Survival in Adults With Heart Failure who Engage in Self-Care Management

Background Self-care management in heart failure (HF) involves decision-making to evaluate, and actions to ameliorate symptoms when they occur. This study sought to compare the risks of all-cause mortality, hospitalization, or emergency-room admission among HF patients who practice above-average self-care management, those who practice below-average self-care management, and those who are symptom-free. Methods A secondary analysis was conducted of data collected on 195 HF patients. A Cox proportional hazards model was used to examine the association between self-care management and event risk. Results The sample consisted of older (mean ± standard deviation = 61.3 ± 11 years), predominantly male (64.6%) adults, with an ejection fraction of 34.7% ± 15.3%; 60.1% fell within New York Heart Association class III or IV HF. During an average follow-up of 364 ± 288 days, 4 deaths, 82 hospitalizations, and 5 emergency-room visits occurred as first events. Controlling for 15 common confounders, those who engaged in above-average self-care management (hazard ratio, .44; 95% confidence interval, .22 to .88; P \u3c .05) and those who were symptom-free (hazard ratio, 0.48; 95% confidence interval, .24 to .97; P \u3c .05) ran a lower risk of an event during follow-up than those engaged in below-average self-care management. Conclusion Symptomatic HF patients who practice above-average self-care management have an event-free survival benefit similar to that of symptom-free HF patients

Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach

A combined experimental and analytical approach was performed for characterizing and modeling triaxially braided composites with a modified subcell modeling strategy. Tensile coupon tests were conducted on a [0deg/60deg/-60deg] braided composite at angles of 0deg, 30deg, 45deg, 60deg and 90deg relative to the axial tow of the braid. It was found that measured coupon strength varied significantly with the angle of the applied load and each coupon direction exhibited unique final failures. The subcell modeling approach implemented into the finite element software LS-DYNA was used to simulate the various tensile coupon test angles. The modeling approach was successful in predicting both the coupon strength and reported failure mode for the 0deg, 30deg and 60deg loading directions. The model over-predicted the strength in the 90deg direction; however, the experimental results show a strong influence of free edge effects on damage initiation and failure. In the absence of these local free edge effects, the subcell modeling approach showed promise as a viable and computationally efficient analysis tool for triaxially braided composite structures. Future work will focus on validation of the approach for predicting the impact response of the braided composite against flat panel impact tests

Molecular Line Emission from Gravitationally Unstable Protoplanetary Disks

In the era of high resolution submillimeter interferometers, it will soon be possible to observe the neutral circumstellar medium directly involved in gas giant planet (GGP) formation at physical scales previously unattainable. In order to explore possible signatures of gas giant planet formation via disk instabilities, we have combined a 3D, non-local thermodynamic equilibrium (LTE) radiative transfer code with a 3D, finite differences hydrodynamical code to model molecular emission lines from the vicinity of a 1.4 M_J self-gravitating proto-GGP. Here, we explore the properties of rotational transitions of the commonly observed dense gas tracer, HCO+. Our main results are the following: 1. Very high lying HCO+ transitions (e.g. HCO+ J=7-6) can trace dense planet forming clumps around circumstellar disks. Depending on the molecular abundance, the proto-GGP may be directly imageable by the Atacama Large Millimeter Array (ALMA). 2. HCO+ emission lines are heavily self-absorbed through the proto-GGP's dense molecular core. This signature is nearly ubiquitous, and only weakly dependent on assumed HCO+ abundances. The self-absorption features are most pronounced at higher angular resolutions. Dense clumps that are not self-gravitating only show minor self-absorption features. 3. Line temperatures are highest through the proto-GGP at all assumed abundances and inclination angles. Conversely, due to self-absorption in the line, the velocity-integrated intensity may not be. High angular resolution interferometers such as the Submillimeter Array (SMA) and ALMA may be able to differentiate between competing theories of gas giant planet formation.Comment: 10 pages, 13 figures; Accepted by Ap

Dynamical mechanism of atrial fibrillation: a topological approach

While spiral wave breakup has been implicated in the emergence of atrial fibrillation, its role in maintaining this complex type of cardiac arrhythmia is less clear. We used the Karma model of cardiac excitation to investigate the dynamical mechanisms that sustain atrial fibrillation once it has been established. The results of our numerical study show that spatiotemporally chaotic dynamics in this regime can be described as a dynamical equilibrium between topologically distinct types of transitions that increase or decrease the number of wavelets, in general agreement with the multiple wavelets hypothesis. Surprisingly, we found that the process of continuous excitation waves breaking up into discontinuous pieces plays no role whatsoever in maintaining spatiotemporal complexity. Instead this complexity is maintained as a dynamical balance between wave coalescence -- a unique, previously unidentified, topological process that increases the number of wavelets -- and wave collapse -- a different topological process that decreases their number.Comment: 15 pages, 14 figure