13,559 research outputs found
Gaussian entanglement induced by an extended thermal environment
We study stationary entanglement among three harmonic oscillators which are
dipole coupled to a one-dimensional or a three-dimensional bosonic environment.
The analysis of the open-system dynamics is performed with generalized quantum
Langevin equations which we solve exactly in Fourier representation. The focus
lies on Gaussian bipartite and tripartite entanglement induced by the highly
non-Markovian interaction mediated by the environment. This environment-induced
interaction represents an effective many-parties interaction with a spatial
long-range feature: a main finding is that the presence of a passive oscillator
is detrimental for the stationary two-mode entanglement. Furthermore, our
results strongly indicate that the environment-induced entanglement mechanism
corresponds to uncontrolled feedback which is predominantly coherent at low
temperatures and for moderate oscillator-environment coupling as compared to
the oscillator frequency.Comment: 15 page, 6 figure
Can the UNAIDS 90-90-90 target be achieved? A systematic analysis of national HIV treatment cascades
Background In 2014, the Joint United Nations Programme on HIV and AIDS (UNAIDS) and partners set the ‘90-90-90 targets’; aiming to diagnose 90% of all HIV positive people, provide antiretroviral therapy (ART) for 90% of those diagnosed and achieve viral suppression for 90% of those treated, by 2020. This results in 81% of all HIV positive people on treatment and 73% of all HIV positive people achieving viral suppression. We aimed to analyse how effective national HIV treatment programmes are at meeting these targets, using HIV care continuums or cascades. Methods We searched for HIV treatment cascades for 196 countries in published papers, conference presentations, UNAIDS databases and national reports. Cascades were constructed using reliable, generalisable, recent data from national, cross-sectional and longitudinal study cohorts. Data were collected for four stages; total HIV positive people, diagnosed, on treatment and virally suppressed. The cascades were categorised as complete (four stages) or partial (3 stages), and analysed for ‘break points’ defined as a drop >10% in coverage between consecutive 90-90-90 targets. Results 69 country cascades were analysed (32 complete, 37 partial). Diagnosis (target one—90%) ranged from 87% (the Netherlands) to 11% (Yemen). Treatment coverage (target two—81% on ART) ranged from 71% (Switzerland) to 3% (Afghanistan). Viral suppression (target three—73% virally suppressed) was between 68% (Switzerland) and 7% (China). Conclusions No country analysed met the 90-90-90 targets. Diagnosis was the greatest break point globally, but the most frequent key break point for individual countries was providing ART to those diagnosed. Large disparities were identified between countries. Without commitment to standardised reporting methodologies, international comparisons are complex
Motion, attention, and visual awareness : correlation and interference studies of human visual cognition
2-16 mu m spectroscopy of micron-sized enstatite (Mg,Fe)(2)Si2O6 silicates from primitive chondritic meteorites
We present mid-infrared spectra from individual enstatite silicate grains separated from primitive type 3 chondritic meteorites. The 2-16 mu m transmission spectra were taken with microspectroscopic Fourier-transform infrared (FT-IR) techniques as part of a project to produce a data base of infrared spectra from minerals of primitive meteorites for comparison with astronomical spectra. In general, the wavelength of enstatite bands increases with the proportion of Fe. However, the wavelengths of the strong En(100) bands at 10.67 and 11.67 decrease with increasing Fe content. The 11.67-mu m band exhibits the largest compositional wavelength shift (twice as large as any other). Our fits of the linear dependence of the pyroxene peaks indicate that crystalline silicate peaks in the 10-mu m spectra of Herbig AeBe stars, HD 179218 and 104237, are matched by pyroxenes of En(90-92) and En(78-80), respectively. If these simplistic comparisons with the astronomical grains are correct, then the enstatite pyroxenes seen in these environments are more Fe-rich than are the forsterite (Fo(100)) grains identified in the far-infrared which are found to be Mg end-member grains. This differs from the general composition of type 3 chondritic meteoritic grains in which the pyroxenes are more Mg-rich than are the olivines from the same meteorite
Local Out-Tournaments with Upset Tournament Strong Components I: Full and Equal {0,1}-Matrix Ranks
A digraph D is a local out-tournament if the outset of every vertex is a tournament. Here, we use local out-tournaments, whose strong components are upset tournaments, to explore the corresponding ranks of the adjacency matrices. Of specific interest is the out-tournament whose adjacency matrix has boolean, nonnegative integer, term, and real rank all equal to the number of vertices, n. Corresponding results for biclique covers and partitions of the digraph are provided
Perioperative infection prophylaxis and risk factor impact in colon surgery
Background: A prospective observational study was undertaken in 2,481 patients undergoing elective colon resection in 114 German centers to identify optimal drug and dosing modalities and risk factors for postoperative infection. Methods: Patients were pair matched using six risk factors and divided into 672 pairs (ceftriaxone vs, other cephalosporins, group A) and 400 pairs (ceftriaxone vs. penicillins, group B). End points were local and systemic postoperative infection and cost effectiveness. Results: Local infection rates were 6.0 versus 6.5% (group A) and 4.0 versus 10.5% (group B); systemic infection rates in groups A and B were 4.9 versus 6.3% and 3.3 versus 10.5%, respectively. Ceftriaxone was more effective than penicillins overall (6.8 vs. 17.8%, p < 0.001). Length of postoperative hospital stay was 16.2 versus 16.9 days (group A) and 15.8 versus 17.6 days (group B). Of the six risk factors, age and concomitant disease were significant for systemic infection, and blood loss, rectum resection and immunosuppressive therapy were significant for local infection. Penicillin was a risk factor compared to ceftriaxone (p < 0.0001). Ceftriaxone saved Q160.7 versus other cephalosporins and O416.2 versus penicillins. Conclusion: Clinical and microbiological efficacy are responsible for the cost effectiveness of ceftriaxone for perioperative prophylaxis in colorectal surgery. Copyright (C) 2000 S. Karger AG, Basel
Weyl formulas for annular ray-splitting billiards
We consider the distribution of eigenvalues for the wave equation in annular
(electromagnetic or acoustic) ray-splitting billiards. These systems are
interesting in that the derivation of the associated smoothed spectral counting
function can be considered as a canonical problem. This is achieved by
extending a formalism developed by Berry and Howls for ordinary (without
ray-splitting) billiards. Our results are confirmed by numerical computations
and permit us to infer a set of rules useful in order to obtain Weyl formulas
for more general ray-splitting billiards
A Comparison Of Nursing Home Residents And Nursing Personnel In Terms Of Perceived Control Over The Resident’S Activities Of Daily Living
This study compared 23 nursing home residents’ and 23 nursing assistants’ control perceptions over the residents’ activities of daily living. Residents’ perceptions were measured with Chang’s Situational Control of Daily Activities (SCDA). Nursing assistants’ perceptions were measured by an investigator designed questionnaire, the Questionnaire of Activities of Daily Living (QADL). Scores of each group were compared using the ^ test which found both groups perceived a high degree of control over the residents’ activities. Based on this finding, the hypothesis that no significant difference in perceived control over residents’ daily activities exists between nursing home residents and nursing assistants was rejected. An additional finding was that nursing home residents’ perceptions of self control over their daily activities correlated significantly, when using Pearson’s v_, with their functional ability as measured by the Functional Assessment Form (FAF). The Geriatric Nurse Clinician can utilize results of this study in various care settings by affording clients maximum perceived control over their lives through shared decision making and providing for maximum client independent functioning. In the roles of practi tioner, counselor, educator and consultant, the Geriatric Nurse Clinician can assist other care providers to apply findings of this study to the development of policies, programs and procedures to enhance the elderly’s control perceptions
Multiplicity at the Stellar/Substellar Boundary in Upper Scorpius
We present the results of a high-resolution imaging survey of 12 brown dwarfs
and very low mass stars in the closest (~145 pc) young (~5 Myr) OB association,
Upper Scorpius. We obtained images with the Advanced Camera for Surveys/High
Resolution Camera on HST through the F555W (V), F775W (i'), and F850LP (z')
filters. This survey discovered three new binary systems, including one
marginally resolved pair with a projected separation of only 4.9 AU, resulting
in an observed binary fraction of 25+/-14% at separations >4 AU. After
correcting for detection biases assuming a uniform distribution of mass ratios
for q>0.6, the estimated binary fraction is 33+/-17%. The binary fraction is
consistent with that inferred for higher-mass stars in Upper Sco, but the
separation and mass ratio distributions appear to be different. All three
low-mass binary systems in Upper Sco are tight (<18 AU) and of similar mass
(q>0.6), consistent with expectations based on previous multiplicity studies of
brown dwarfs and very low mass stars in the field and in open clusters. The
implication is that the distinct separation and mass ratio distributions of
low-mass systems are set in the formation process or at very young ages, rather
than by dynamical disruption of wide systems at ages >5 Myr. Finally, we
combine the survey detection limits with the models of Burrows et al. (1997) to
show that there are no planets or very low-mass brown dwarfs with masses >10
M_J at projected separations >20 AU, or masses >5 M_J at projected separations
>40 AU orbiting any of the low-mass (0.04-0.10 M_sun) objects in our sample.Comment: Accepted for publication in ApJ; 10 pages, 4 figures in emulateapj
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