8,277 research outputs found
Land landing couch dynamics computer program
Computer programs perform landing stability studies of mechanical impact system designs for advanced spacecraft. The programs consider variation in spacecraft vertical and horizontal velocity, attitude and orientation, shock strut load-stroke characteristics, and ground coefficient of friction
Goethite on Mars - A laboratory study of physically and chemically bound water in ferric oxides
Thermogravimetric study of physically and chemically bound water in ferric oxides of limonite with application to goethite on Mar
Improved Healing of Pressure Ulcers Using Dermapulse, A New Electrical Stimulation Device
A double-blind, clinical study of pulsed electrical stimulation using the Dermapulse® device was carried out on 40 pressure ulcers, randomized to receive either active (stim) or sham treatment.
Electrodes were placed over saline-moistened gauze on the ulcers. An electrical current of 35mA was delivered to the wound tissues at a frequency of 128 pulses per second. Polarity was negative until the wound debrided, then alternated from .positive to negative every three days. Ulcers were treated for 30 minutes twice daily for four weeks, after which sham patients could cross over to active treatment, and stim patients could continue active treatment. Ulcer healing was determined by measuring the length and width of the ulcer and calculating the L x W product. The same clinicians measured the ulcers each week, were kept blinded to treatment group, and were not the same persons who applied the treatment.
Nine centers treated 40 ulcers (19 sham and 21 stim). Analysis of the characteristics of the patients, the ulcers, and concomitant wound care by both univariate and multivariate analyses showed comparability of the groups. After four weeks, the stim ulcers healed more than twice as much as the sham ulcers (49.8% vs. 23.4%; (p = 0.042). The stim ulcers healed 12.5% per week compared to 5.8% for the sham group. In the 15 crossover patients, four weeks of active stimulation caused nearly four times as much healing as their four weeks of sham treatment (47.9% vs. 13.4%; p = 0.012). By the last week of-active stimulation they had healed an average of 64%, and complete healing occurred in 40% of these ulcers after an average of nine weeks. Seventeen of the active treatment ulcers had extended therapy, and by their last week of treatment had healed an average of 75%. Forty-one percent of these ulcers healed completely after an average of 11.8 weeks. There were no significant safety problems identified
Dissipative Transport of a Bose-Einstein Condensate
We investigate the effects of impurities, either correlated disorder or a
single Gaussian defect, on the collective dipole motion of a Bose-Einstein
condensate of Li in an optical trap. We find that this motion is damped at
a rate dependent on the impurity strength, condensate center-of-mass velocity,
and interatomic interactions. Damping in the Thomas-Fermi regime depends
universally on the disordered potential strength scaled to the condensate
chemical potential and the condensate velocity scaled to the peak speed of
sound. The damping rate is comparatively small in the weakly interacting
regime, and the damping in this case is accompanied by strong condensate
fragmentation. \textit{In situ} and time-of-flight images of the atomic cloud
provide evidence that this fragmentation is driven by dark soliton formation.Comment: 14 pages, 20 figure
Charge Management for Gravitational Wave Observatories using UV LEDs
Accumulation of electrical charge on the end mirrors of gravitational wave
observatories, such as the space-based LISA mission and ground-based LIGO
detectors, can become a source of noise limiting the sensitivity of such
detectors through electronic couplings to nearby surfaces. Torsion balances
provide an ideal means for testing gravitational wave technologies due to their
high sensitivity to small forces. Our torsion pendulum apparatus consists of a
movable Au-coated Cu plate brought near a Au-coated Si plate pendulum suspended
from a non-conducting quartz fiber. A UV LED located near the pendulum
photoejects electrons from the surface, and a UV LED driven electron gun
directs photoelectrons towards the pendulum surface. We have demonstrated both
charging and discharging of the pendulum with equivalent charging rates of
, as well as spectral measurements of the pendulum
charge resulting in a white noise level equivalent to .Comment: 5 pages, submitted to PR
The EU and Asia within an evolving global order: what is Europe? Where is Asia?
The papers in this special edition are a very small selection from those presented at the EU-NESCA (Network of European Studies Centres in Asia) conference on "the EU and East Asia within an Evolving Global Order: Ideas, Actors and Processes" in November 2008 in Brussels. The conference was the culmination of three years of research activity involving workshops and conferences bringing together scholars from both regions primarily to discuss relations between Europe and Asia, perceptions of Europe in Asia, and the relationship between the European regional project and emerging regional forms in Asia. But although this was the last of the three major conferences organised by the consortium, it in many ways represented a starting point rather than the end; an opportunity to reflect on the conclusions of the first phase of collaboration and point towards new and continuing research agendas for the future
Evaluation of subcutaneous proleukin (Interleukin-2) in a randomized international trial (ESPRIT): Geographical and gender differences in the baseline characteristics of participants
Background: ESPRIT, is a phase III, open-label, randomized, international clinical trial evaluating the effects of subcutaneous recombinant interleukin-2 (rIL-2) plus antiretroviral therapy (ART) versus ART alone on HIV-disease progression and death in HIV-1-infected individuals with CD4+ T-cells ≥300 cells/μL. Objectives: To describe the baseline characteristics of participants randomized to ESPRIT overall and by geographic location. Method: Baseline characteristics of randomized participants were summarized by region. Results: 4,150 patients were enrolled in ESPRIT from 254 sites in 25 countries. 41%, 27%, 16%, 11%, and 5% were enrolled in Europe, North America, South America, Asia, and Australia, respectively. The median age was 40 years, 81% were men, and 76%, 11%, and 9% were Caucasian, Asian, and African American or African, respectively. 44% of women enrolled (n = 769) were enrolled in Thailand and Argentina. Overall, 55% and 38% of the cohort acquired HIV through male homosexual and heterosexual contact, respectively. 25% had a prior history of AIDS-defining illness; Pneumocystis jirovecii pneumonia, M. tuberculosis, and esophageal candida were most commonly reported. Median nadir and baseline CD4+ T-cell counts were 199 and 458 cells/μL, respectively. 6% and 13% were hepatitis B or C virus coinfected, respectively. Median duration of antiretroviral therapy (ART) was 4.2 years; the longest median duration was in Australia (5.2 years) and the shortest was in Asia (2.3 years). 17%, 13%, and 69% of participants began ART before 1995, between 1996 and 1997, and from 1998 onward, respectively. 86% used ART from two or more ART classes, with 49% using a protease inhibitor-based regimen and 46% using a nonnucleoside reverse transcriptase inhibitor-based regimen. 78% had plasma HIV RNA below detection (<500 cp/mL). Conclusion: ESPRIT has enrolled a diverse population of HIV-infected individuals including large populations of women and patients of African-American/African and Asian ethnicity often underrepresented in HIV research. As a consequence, the results of the study may have wide global applicability
A Compact Supermassive Binary Black Hole System
We report on the discovery of a supermassive binary black hole system in the
radio galaxy 0402+379, with a projected separation between the two black holes
of just 7.3 pc. This is the closest black hole pair yet found by more than two
orders of magnitude. These results are based upon recent multi-frequency
observations using the Very Long Baseline Array (VLBA) which reveal two
compact, variable, flat-spectrum, active nuclei within the elliptical host
galaxy of 0402+379. Multi-epoch observations from the VLBA also provide
constraints on the total mass and dynamics of the system. Low spectral
resolution spectroscopy using the Hobby-Eberly Telescope indicates two velocity
systems with a combined mass of the two black holes of ~1.5 x 10^8 solar
masses. The two nuclei appear stationary while the jets emanating from the
weaker of the two nuclei appear to move out and terminate in bright hot spots.
The discovery of this system has implications for the number of close binary
black holes that might be sources of gravitational radiation. Green Bank
Telescope observations at 22 GHz to search for water masers in this interesting
system are also presented.Comment: 34 pages, 7 figures, Accepted to The Astrophysical Journa
An end to Nordic exceptionalism? Europeanisation and Nordic development policies
The Nordic countries have traditionally been praised for their generous and advanced development policies. Recently, however, it has been claimed that the Nordic model has faded: that the Nordic donors have become more similar to other European donors. One possible reason for such trends is influences from EU policies, that is, Europeanisation. This article critically evaluates such claims by presenting arguments for and against Europeanisation effects. We argue that changes have indeed taken place. The Nordic exceptionalism has been eroded. At the same time, a convergence of European aid policies has occurred. The question is if this is the consequence of Europeanisation – or is it rather a result of Nordicisation (the Nordic countries influencing the EU), or perhaps like-mindisation (a broader set of progressive member states having impact upon EU policies)? We suggest that Europeanisation has been extremely weak while there is strong evidence of Nordicisation but also, and increasingly, of like-mindisation. Today, a core group of mainly northern member states, including the Nordics, are the main driving forces behind European aid convergence
Multipole structure and coordinate systems
Multipole expansions depend on the coordinate system, so that coefficients of
multipole moments can be set equal to zero by an appropriate choice of
coordinates. Therefore, it is meaningless to say that a physical system has a
nonvanishing quadrupole moment, say, without specifying which coordinate system
is used. (Except if this moment is the lowest non-vanishing one.) This result
is demonstrated for the case of two equal like electric charges. Specifically,
an adapted coordinate system in which the potential is given by a monopole term
only is explicitly found, the coefficients of all higher multipoles vanish
identically. It is suggested that this result can be generalized to other
potential problems, by making equal coordinate surfaces coincide with the
potential problem's equipotential surfaces.Comment: 2 figure
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