3,905 research outputs found
A comparison of broad iron emission lines in archival data of neutron star low-mass X-ray binaries
Relativistic X-ray disk-lines have been found in multiple neutron star
low-mass X-ray binaries, in close analogy with black holes across the
mass-scale. These lines have tremendous diagnostic power and have been used to
constrain stellar radii and magnetic fields, often finding values that are
consistent with independent timing techniques. Here, we compare CCD-based data
from Suzaku with Fe K line profiles from archival data taken with gas-based
spectrometers. In general, we find good consistency between the gas-based line
profiles from EXOSAT, BeppoSAX and RXTE and the CCD data from Suzaku,
demonstrating that the broad profiles seen are intrinsic to the line and not
broad due to instrumental issues. However, we do find that when fitting with a
Gaussian line profile, the width of the Gaussian can depend on the continuum
model in instruments with low spectral resolution, though when the different
models fit equally well the line widths generally agree. We also demonstrate
that three BeppoSAX observations show evidence for asymmetric lines, with a
relativistic disk-line model providing a significantly better fit than a
Gaussian. We test this by using the posterior predictive p-value method, and
bootstrapping of the spectra to show that such deviations from a Gaussian are
unlikely to be observed by chance.Comment: 13 pages, 9 figures, accepted to Ap
The Quiescent X-ray Spectrum of Accreting Black Holes
The quiescent state is the dominant accretion mode for black holes on all
mass scales. Our knowledge of the X-ray spectrum is limited due to the
characteristic low luminosity in this state. Herein, we present an analysis of
the sample of dynamically-confirmed stellar-mass black holes observed in
quiescence in the \textit{Chandra/XMM-Newton/Suzaku} era resulting in a sample
of 8 black holes with 570 ks of observations. In contrast to the
majority of AGN where observations are limited by contamination from diffuse
gas, the stellar-mass systems allow for a clean study of the X-ray spectrum
resulting from the accretion flow alone. The data are characterized using
simple models. We find a model consisting of a power-law or thermal
bremsstrahlung to both provide excellent descriptions of the data, where we
measure and
respectively in the 0.3 -- 10 keV bandpass, at a median luminosity of . This result in discussed in the context of our
understanding of the accretion flow onto stellar and supermassive black holes
at low luminosities.Comment: 12 pages, 5 figures, 2 tables, MNRAS accepte
Vertical Conflicts: The Role of State Law in Suits under Section 301
One of the most difficult practical problems posed by our federal system arises when the judicial institutions of one law-making authority are enlisted to enforce and protect rights created by another. While the United States Supreme Court through its appellate jurisdiction is the institution charged with the final responsibility for overseeing a satisfactory solution to this problem, and while the Court can indicate how competing interests are to be harmonized in specific controversies and provide some principles which may be useful in different contexts, it cannot review every state 301 suit. In the long run, success depends upon the earnest labors of state courts to identify the policies which are in conflict and bring their energies to bear in an effort to achieve a true resolution of the competing interests. For the most part, the Court has delineated the policy values under 301 law, and what remains is the application of these policies to specific issues which arise during the course of litigation. It is the purpose of this note to engage in the type of analytical processes state courts must undertake and to reach some conclusions concerning the role of state law in suits brought under section 301
The Impact Of Cultural Differences On The Effectiveness Of Advertisements On The Internet: A Comparison Among The United States, China, And Germany
Hall and Hall (1990) classify German culture as a low-context culture, American culture as a medium/low-context culture, and Chinese culture as a high-context culture. A low-context culture is one where the words contain most of the information needed and there is little need to rely on the context of the events/message to help interpreting the meaning of the message/events. In contrast, a high-context culture is one where the context of the message is as important as or even more important than the words. This paper focuses on selected cultural differences among Germany, United States, and China, and the impact of these differences on the various aspects of consumer behavior. Specifically, it is focusing on the impact of cultural context on the effectiveness of the different styles of advertising.
Effects of dietary L -arginine on structure and function of flow-restricted vein grafts
AbstractPurpose: Experiments were designed to determine effects of dietary supplementation with L -arginine on structure and function of flow-restricted vein grafts. Methods: Saphenous veins were placed as bilateral interposition grafts in femoral arteries of two groups of adult male mongrel dogs; one group was maintained on a normal diet (control), the other group supplemented with L -arginine (200 mg/kg per day) beginning 1 week before surgery. In each dog, flow was reduced by 50% in one graft by placing an adjustable clamp on the artery distal to the distal anastomosis. Plasma amino acids and oxidized products of nitric oxide (NOx ) were measured before and after L -arginine feeding. At postoperative week 4, grafts were removed and prepared for organ chamber studies to determine functions of the endothelium or smooth muscle and for histology. Results: Plasma L -arginine increased within 3 hours after feeding and increased from 141 ± 8 nmol/mL to 169 ± 11 nmol/mL (n = 6) after 5 weeks of supplementation. Plasma ornithine and citrulline paralleled arginine, whereas circulating NOx was unchanged. Maximal contractions to 60 mmol/L KCl were reduced in grafts from L -arginine–fed dogs. Endothelium-dependent relaxations to the calcium ionophore A23187 and relaxations of the smooth muscle NO were reduced in grafts from L -arginine–fed dogs. Neointimal hyperplasia was increased in grafts with reduced flow and not affected by arginine feeding. Conclusions: Dietary supplementation with L -arginine did not increase plasma NO in dogs with peripheral vein grafts or increase endothelium-dependent relaxations in control or flow-restricted grafts. Therefore, dietary supplementation with L -arginine may not improve long-term functions of flow-restricted peripheral bypass grafts. (J Vasc Surg 2001;33:829-39.
Palliative Care Consultations in Nursing Homes and Reductions in Acute Care Use and Potentially Burdensome End-of-Life Transitions
To evaluate how receipt and timing of nursing home (NH) palliative care consults (primarily by nurse practitioners with palliative care expertise) is associated with end-of-life care transitions and acute care us
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Genotyping Analyses of Tuberculosis Cases in U.S.- and Foreign-Born Massachusetts Residents
We used molecular genotyping to further understand the epidemiology and transmission patterns of tuberculosis (TB) in Massachusetts. The study population included 983 TB patients whose cases were verified by the Massachusetts Department of Public Health between July 1, 1996, and December 31, 2000, and for whom genotyping results and information on country of origin were available. Two hundred seventy-two (28%) of TB patients were in genetic clusters, and isolates from U.S-born were twice as likely to cluster as those of foreign-born (odds ratio [OR] 2.29, 95% confidence interval [CI] 1.69, 3.12). Our results suggest that restriction fragment length polymorphism analysis has limited capacity to differentiate TB strains when the isolate contains six or fewer copies of IS6110, even with spoligotyping. Clusters of TB patients with more than six copies of IS6110 were more likely to have epidemiologic connections than were clusters of TB patients with isolates with few copies of IS6110 (OR 8.01, 95%; CI 3.45,18.93)
Nutritional Quality of Leaves and Unripe Fruit Consumed as Famine Foods by the Flying Foxes of Samoa
Many tropical herbivores alter their diets throughout the year in
response to different levels of food availability. Fruit bats, including Pteropus
samoensis Peale and Pteropus tonganus Quoy & Gaimard, are phytophagous
species that may increase their consumption of foods such as unripe fruit and
leaves in periods of low fruit diversity and volume. These periods include the
tropical dry season or following the frequent hurricanes that batter the Samoan
Archipelago. We examined the nutritional composition of leaves and immature
fruits and compared the levels of organic and mineral nutrients with those of
ripe fruit. We used principal components analysis (PCA) to examine patterns
of variation in nutrient components of leaves, unripe fruit, and ripe fruit, as
well as to compare the mean levels of nutrients. Overall, unripe fruit provided
levels of nutrients comparable with those of ripe fruit of the same species for
many organic and mineral components. Unripe fruit were only half as rich in
iron as ripe fruit, but unripe fruit had high levels of calcium compared with
ripe fruit of the same species. Leaves are often cited as a rich source of protein
for fruit bats, and our results were consistent with this suggestion. Leaves were
also found to be rich in zinc, manganese, and calcium. Therefore, flying foxes
and other herbivores probably do not avoid unripe fruits and leaves because of
their low nutrient levels. It may be that these famine foods are not normally
consumed because of the presence of secondary compounds, low concentrations
of palatable sugars, or a distasteful and hard pericarp on unripe fruits
DeepScribe: Localization and Classification of Elamite Cuneiform Signs Via Deep Learning
Twenty-five hundred years ago, the paperwork of the Achaemenid Empire was
recorded on clay tablets. In 1933, archaeologists from the University of
Chicago's Oriental Institute (OI) found tens of thousands of these tablets and
fragments during the excavation of Persepolis. Many of these tablets have been
painstakingly photographed and annotated by expert cuneiformists, and now
provide a rich dataset consisting of over 5,000 annotated tablet images and
100,000 cuneiform sign bounding boxes. We leverage this dataset to develop
DeepScribe, a modular computer vision pipeline capable of localizing cuneiform
signs and providing suggestions for the identity of each sign. We investigate
the difficulty of learning subtasks relevant to cuneiform tablet transcription
on ground-truth data, finding that a RetinaNet object detector can achieve a
localization mAP of 0.78 and a ResNet classifier can achieve a top-5 sign
classification accuracy of 0.89. The end-to-end pipeline achieves a top-5
classification accuracy of 0.80. As part of the classification module,
DeepScribe groups cuneiform signs into morphological clusters. We consider how
this automatic clustering approach differs from the organization of standard,
printed sign lists and what we may learn from it. These components, trained
individually, are sufficient to produce a system that can analyze photos of
cuneiform tablets from the Achaemenid period and provide useful transliteration
suggestions to researchers. We evaluate the model's end-to-end performance on
locating and classifying signs, providing a roadmap to a linguistically-aware
transliteration system, then consider the model's potential utility when
applied to other periods of cuneiform writing.Comment: Currently under review in the ACM JOCC
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