Variable sweep aircraft Patent

Development and characteristics of variable sweep wing control system for supersonic aircraf

Human immunodeficiency virus treatment-induced adipose tissue pathology and lipoatrophy: Prevalence and metabolic consequences

Lipoatrophy and metabolic complications of treatment of human immunodeficiency virus (HIV) infection may share common associations with adipose tissue pathology and inflammation. To investigate these relationships, we undertook a large-scale study of adipose tissue, body composition, and metabolic outcomes among HIV-infected adult men at a tertiary hospital HIV cohort during the period 2001-2007. Methods. Assessments included adipose biopsies (np211) for investigation of adipocyte mitochondrial DNA content, adipocytokine expression, and adipose macrophage content; and whole-body dual-energy X-ray absorptiometry (DEXA) scans (np225) for objective body composition changes; 138 individuals contributed both biopsy and DEXA data. Results. Compared with 78 treatment-naive control subjects, 98 zidovudine recipients (48%) and 49 stavudine recipients (67%) had leg fat measures <10% threshold value. Adipose samples associated with current stavudine or zidovudine (np99) revealed significant adipocyte mitochondrial DNA depletion, adipose tissue macrophage infiltration, and elevated proinflammatory cytokine levels, compared with samples from control subjects and nonthymidine nucleoside reverse-transcriptase inhibitor (NRTI) recipients (all P<.05). Improvements in adipose pathology after NRTI switching (np21 longitudinal samples) correlated with increased preswitch adipose inflammation and less severe fat loss (both P<.05). Elevated ratios of total to high-density lipoprotein cholesterol levels and Homeostatic Metabolic Assessment scores correlated independently with lipoatrophy severity (P<.05) and increased body mass index (P<.05) in thymidine NRTI-experienced individuals. No effect of demographic or HIV-related variables, or HIV protease inhibitor therapy exposure was detected. Conclusions. Adipose tissue pathology and lipoatrophic fat loss are highly prevalent among recipients of stavudine- or zidovudine-based HIV treatment and are associated with adverse metabolic outcomes. Restoring adipose tissue health appears to be an important issue in the long-term treatment of this patient population

Radiographic measurements of the trachea in domestic short haired and Persian cats

Tracheal diameter can be assessed from a thoracic radiograph, with assessment of tracheal diameter in dogs based on ratios between tracheal diameter and a skeletal measurement – however reference ranges are not available for the cat. Tracheal narrowing may cause significant clinical problems, although tracheal hypoplasia in dogs may be clinically silent, and is rarely reported in cats (both mesati- and brachycephalic). The tracheal diameter and trachea:thoracic inlet and trachea:rib ratios were calculated for populations of Domestic Short Haired (DSH) (n=68) and Persian (n=40) cats. This gave reference ranges for radiographic tracheal measurements in these breeds. It is proposed that the tracheal diameter in a normal DSH cat should be 18% of the diameter of the thoracic inlet, and compared to 20% in Persian cats

An evaluation of helicopter noise and vibration ride qualities criteria

Two methods of quantifying helicopter ride quality; absorbed power for vibration only and the NASA ride comfort model for both noise and vibration are discussed. Noise and vibration measurements were obtained on five operational US Army helicopters. The data were converted to both absorbed power and DISC's (discomfort units used in the NASA model) for specific helicopter flight conditions. Both models indicate considerable variation in ride quality between the five helicopters and between flight conditions within each helicopter

Electrical characterization of a Mapham inverter using pulse testing techniques

Electric power requirements for aerospace missions have reached megawatt power levels. Within the next few decades, it is anticipated that a manned lunar base, interplanetary travel, and surface exploration of the Martian surface will become reality. Several research and development projects aimed at demonstrating megawatt power level converters for space applications are currently underway at the NASA Lewis Research Center. Innovative testing techniques will be required to evaluate the components and converters, when developed, at their rated power in the absence of costly power sources, loads, and cooling systems. Facilities capable of testing these components and systems at full power are available, but their use may be cost prohibitive. The use of a multiple pulse testing technique is proposed to determine the electrical characteristics of large megawatt level power systems. Characterization of a Mapham inverter is made using the proposed technique and conclusions are drawn concerning its suitability as an experimental tool to evaluate megawatt level power systems

Association between low 25(OH) vitamin D levels, antiretroviral therapy and metabolic profile in a cohort of treated ahd therapy naive HIV positive patients in Western Australia

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Dipolar Bose gases: Many-body versus mean-field description

We characterize zero-temperature dipolar Bose gases under external spherical confinement as a function of the dipole strength using the essentially exact many-body diffusion Monte Carlo (DMC) technique. We show that the DMC energies are reproduced accurately within a mean-field framework if the variation of the s-wave scattering length with the dipole strength is accounted for properly. Our calculations suggest stability diagrams and collapse mechanisms of dipolar Bose gases that differ significantly from those previously proposed in the literature

The calibration of photographic and spectroscopic films: Reciprocity failure and thermal responses of IIaO film at liquid nitrogen temperatures

Reciprocity failure was examined for IIaO spectroscopic film. The results indicate reciprocity failure occurs at three distinct minimum points in time; 15 min, 30 min and 90 min. The results are unique because theory suggests only one minimum reciprocity failure point should occur. When incubating 70mm IIaO film for 15 and 30 min at temperatures of 30, 40, 50, and 60 C and then placing in a liquid nitrogen bath at a temperature of -190 C the film demonstrated an increase of the optical density when developed at a warm-up time of 30 min. Longer warm-up periods of 1, 2 and 3 hrs yield a decrease in optical density of the darker wedge patterns; whereas, shorter warm-up times yield an overall increase in the optical densities

Comparative Monte Carlo Efficiency by Monte Carlo Analysis

We propose a modified power method for computing the subdominant eigenvalue $\lambda_2$ of a matrix or continuous operator. Here we focus on defining simple Monte Carlo methods for its application. The methods presented use random walkers of mixed signs to represent the subdominant eigenfuction. Accordingly, the methods must cancel these signs properly in order to sample this eigenfunction faithfully. We present a simple procedure to solve this sign problem and then test our Monte Carlo methods by computing the $\lambda_2$ of various Markov chain transition matrices. We first computed ${\lambda_2}$ for several one and two dimensional Ising models, which have a discrete phase space, and compared the relative efficiencies of the Metropolis and heat-bath algorithms as a function of temperature and applied magnetic field. Next, we computed $\lambda_2$ for a model of an interacting gas trapped by a harmonic potential, which has a mutidimensional continuous phase space, and studied the efficiency of the Metropolis algorithm as a function of temperature and the maximum allowable step size $\Delta$. Based on the $\lambda_2$ criterion, we found for the Ising models that small lattices appear to give an adequate picture of comparative efficiency and that the heat-bath algorithm is more efficient than the Metropolis algorithm only at low temperatures where both algorithms are inefficient. For the harmonic trap problem, we found that the traditional rule-of-thumb of adjusting $\Delta$ so the Metropolis acceptance rate is around 50% range is often sub-optimal. In general, as a function of temperature or $\Delta$, $\lambda_2$ for this model displayed trends defining optimal efficiency that the acceptance ratio does not. The cases studied also suggested that Monte Carlo simulations for a continuum model are likely more efficient than those for a discretized version of the model.Comment: 23 pages, 8 figure