3,149 research outputs found
An analysis of in vitro T cell responsiveness in lepromatous leprosy
[No abstract available
Shaped nozzles for cryogenic buffer gas beam sources
Cryogenic buffer gas beams are important sources of cold molecules. In this
work we explore the use of a converging-diverging nozzle with a buffer-gas
beam. We find that, under appropriate circumstances, the use of a nozzle can
produce a beam with improved collimation, lower transverse temperatures, and
higher fluxes per solid angle
Trade patterns, trade balances and idiosyncratic shocks
International Macroeconomics has long sought an explanation for current account fluctuations that matches the data. The approaches have typically focused on better models and new macroeconomic variables. We demonstrate the limitations of this approach by showing that idiosyncratic shocks are an important cause of macroeconomic volatility even for large countries. When explaining these fluctuations, standard macroeconomic models generally assume that firms are small and that their microeconomic shocks cancel out. We show that the high degree of concentration of bilateral trade flows means that idiosyncratic shocks can have a significant impact on aggregate economic fluctuations. We theoretically develop a descomposition components. Taking the model to data on bilateral trade flows from 1970 to 1997, we find that the most comprehensive macroeconomic model can only account for at most half of the observed variance in trade account volumes of each country. Thus, this paper highlights the importance of considering disaggregated data when modeling the current accoun
Integration of Dirac-Jacobi structures
We study precontact groupoids whose infinitesimal counterparts are
Dirac-Jacobi structures. These geometric objects generalize contact groupoids.
We also explain the relationship between precontact groupoids and homogeneous
presymplectic groupoids. Finally, we present some examples of precontact
groupoids.Comment: 10 pages. Brief changes in the introduction. References update
The Effect of Pressure Fluctuations on the Shapes of Thinning Liquid Curtains
We consider the time-dependent response of a gravitationally thinning inviscid liquid sheet (a coating curtain) leaving a vertical slot to sinusoidal ambient pressure disturbances. The theoretical investigation employs the hyperbolic partial differential equation developed by Weinstein et al. (Phys. Fluids, vol. 9, issue 12, 1997, pp. 3625–3636). The response of the curtain is characterized by the slot Weber number, We0=ρqV/2σ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eWe0=ρqV/2σWe0=ρqV/2σ, where V role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eVV is the speed of the curtain at the slot, q role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eqq is the volumetric flow rate per unit width, σ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eσσ is the surface tension and ρ role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eρρ is the fluid density. Flow disturbances travel along characteristics with speeds relative to the curtain of ±uV/We0 role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3e±uV/We0−−−−−−−√±uV/We0, where u=V2+2gx role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eu=V2+2gx−−−−−−−−√u=V2+2gx is the curtain speed at a distance x role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3exx downstream from the slot. Here g is the acceleration of gravity. When the flow is subcritical (We0We0\u3c1We0We0We0. In contrast, all disturbances travel downstream in supercritical curtains (We0\u3e1 role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eWe0\u3e1We0\u3e1) and the slope of the curtain at the slot is vertical. Here, we specifically examine the curtain response under supercritical and subcritical flow conditions near We0=1 role= presentation style= box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline-table; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative; \u3eWe0=1We0=1 to deduce whether there is a substantial change in the overall shape and magnitude of the curtain responses. Despite the local differences in the curtain solution near the slot, we find that subcritical and supercritical curtains have similar responses for all imposed sinusoidal frequencies
Experimental Implementation of the Quantum Baker's Map
This paper reports on the experimental implementation of the quantum baker's
map via a three bit nuclear magnetic resonance (NMR) quantum information
processor. The experiments tested the sensitivity of the quantum chaotic map to
perturbations. In the first experiment, the map was iterated forward and then
backwards to provide benchmarks for intrinsic errors and decoherence. In the
second set of experiments, the least significant qubit was perturbed in between
the iterations to test the sensitivity of the quantum chaotic map to applied
perturbations. These experiments are used to investigate previous predicted
properties of quantum chaotic dynamics.Comment: submitted to PR
A Volumetric Method for Quantifying Atherosclerosis in Mice by Using MicroCT: Comparison to En Face
Precise quantification of atherosclerotic plaque in preclinical models of atherosclerosis requires the volumetric assessment of the lesion(s) while maintaining in situ architecture. Here we use micro-computed tomography (microCT) to detect ex vivo aortic plaque established in three dyslipidemic mouse models of atherosclerosis. All three models lack the low-density lipoprotein receptor (Ldlr−/−), each differing in plaque severity, allowing the evaluation of different plaque volumes using microCT technology. From clearly identified lesions in the thoracic aorta from each model, we were able to determine plaque volume (0.04–3.1 mm3), intimal surface area (0.5–30 mm2), and maximum plaque (intimal-medial) thickness (0.1–0.7 mm). Further, quantification of aortic volume allowed calculation of vessel occlusion by the plaque. To validate microCT for future preclinical studies, we compared microCT data to intimal surface area (by using en face methodology). Both plaque surface area and plaque volume were in excellent correlation between microCT assessment and en face surface area (r2 = 0.99, p<0.0001 and r2 = 0.95, p<0.0001, respectively). MicroCT also identified internal characteristics of the lipid core and fibrous cap, which were confirmed pathologically as Stary type III-V lesions. These data validate the use of microCT technology to provide a more exact empirical measure of ex vivo plaque volume throughout the entire intact aorta in situ for the quantification of atherosclerosis in preclinical models
Electrostatic guiding of the methylidyne radical at cryogenic temperatures
We have produced a cryogenic buffer-gas cooled beam of the diatomic molecular
radical CH (methylidyne). This molecule is of interest for studying cold
chemical reactions and fundamental physics measurements. Its light mass and
ground-state structure make it a promising candidate for electrostatic guiding
and Stark deceleration, which allows for control over its kinetic energy. This
control can facilitate studies of reactions with tuneable collision energies
and trapping for precise spectroscopic studies. Here, we have demonstrated
electrostatic guiding of CH with fluxes up to molecules per steradian
per pulseComment: 10 pages, 10 figure
Safety and Efficacy of Long-Term Use of Extended Release Cornstarch Therapy for Glycogen Storage Disease Types 0, III, VI, and IX
Background: Impaired glycogen release with fasting results in hypoglycemia in the glycogen storage diseases. A waxy-maize extended release cornstarch was introduced in the United States in 2012 to maintain glucose concentrations during the overnight period, but no studies have assessed the long-term safety and efficacy of this product in the ketotic forms of GSD.Objective: To assess long-term safety and efficacy of modified cornstarch in patients with ketotic forms of GSD.Design: An open label overnight trial of extended release cornstarch was performed. Subjects who had a successful trial (defined as optimal metabolic control lasting 2 or more hours more than with traditional cornstarch) were given the option of continuing into the long-term observational phase. Participants were assessed biochemically at baseline and after 12 months.Results: A total of 16 subjects participated in the open label trial. Efficacy was demonstrated in 100% of the subjects with GSD 0, III, VI, and IX. Of the patients who entered the longitudinal phase, long-term data are available for all subjects. The mean duration of overnight fasting on traditional cornstarch prior to the study for the cohort was 4.9 hours and 9.6 hours on the extended release cornstarch (P < 0.001). All laboratory markers of metabolic control have remained stable in the chronically treated patients.Conclusion: Extended release cornstarch dramatically prolongs the overnight fast duration, maximizes safety from hypoglycemic events, reduces the possibility of sleep deprivation, and improves the quality of life of patients by eliminating the need to awaken without fail for middle of the night therapy without sacrificing metabolic control
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