1,085 research outputs found
FUSE Observations of the Dwarf Nova SW UMa During Quiescence
We present spectroscopic observations of the short-period cataclysmic
variable SW Ursa Majoris, obtained by the Far Ultraviolet Spectroscopic
Explorer (FUSE) satellite while the system was in quiescence. The data include
the resonance lines of O VI at 1031.91 and 1037.61 A. These lines are present
in emission, and they exhibit both narrow (~ 150 km/s) and broad (~ 2000 km/s)
components. The narrow O VI emission lines exhibit unusual double-peaked and
redshifted profiles. We attribute the source of this emission to a cooling flow
onto the surface of the white dwarf primary. The broad O VI emission most
likely originates in a thin, photoionized surface layer on the accretion disk.
We searched for emission from H_2 at 1050 and 1100 A, motivated by the
expectation that the bulk of the quiescent accretion disk is in the form of
cool, molecular gas. If H_2 is present, then our limits on the fluxes of the
H_2 lines are consistent with the presence of a surface layer of atomic H that
shields the interior of the disk. These results may indicate that accretion
operates primarily in the surface layers of the disk in SW UMa. We also
investigate the far-UV continuum of SW UMa and place an upper limit of 15,000 K
on the effective temperature of the white dwarf.Comment: 21 Pages, 3 figures, to be published in Ap
Chandra Observation of V426 Oph: Weighing the Evidence for a Magnetic White Dwarf
We report the results of a 45 ks Chandra observation of the cataclysmic
variable V426 Ophiuchus. The high resolution spectrum from the high-energy
transmission grating spectrometer is most consistent with a cooling flow model,
placing V426 Oph among the group of CVs including U Gem and EX Hya. An
uninterrupted lightcurve was also constructed, in which we detect a significant
4.2 hr modulation together with its first harmonic at 2.1 hrs. Reanalysis of
archival Ginga, and ROSAT X-ray lightcurves also reveals modulations at periods
consistent with 4.2 and/or 2.1 hrs. Furthermore, optical photometry in V,
simultaneous with the Chandra observation, indicates a modulation
anti-correlated with the X-ray, and later more extensive R band photometry
finds a signal at ~2.1 hrs. The earlier reported X-ray periods at ~0.5 and 1
hrs appear to be only transient and quasi-periodic in nature. In contrast, the
4.2 hr period or its harmonic are stable and persistent in X-ray/optical data
from 1988 to 2003. This periodicity is clearly distinct from the 6.85 hr orbit,
and could be due to the spin of the white dwarf. If this is the case, V426 Oph
would be the first long period intermediate polar with a ratio P_spin/P_orb of
0.6. However, this interpretation requires unreasonable values of magnetic
field strength and mass accretion rate.Comment: 11 pages, 7 figures, 5 tables. Accepted for publication in the
Astrophysical Journal (to appear August 2004
Формирование механических характеристик тонкой углеродистой латунированной проволоки в процессе тонкого волочения
Материалы XIII Междунар. науч.-техн. конф. студентов, магистрантов и молодых ученых, Гомель, 25–26 апр. 2013 г
Testosterone treatment is not associated with increased risk of adverse cardiovascular events: results from the Registry of Hypogonadism in Men (RHYME).
SummaryAims The aim of this study was to assess cardiovascular (CV) safety of testosterone replacement therapy (TRT) in a large, diverse cohort of European men with hypogonadism (HG). Methods The Registry of Hypogonadism in Men (RHYME) was designed as a multi-national, longitudinal disease registry of men diagnosed with hypogonadism (HG) at 25 clinical sites in six European countries. Data collection included a complete medical history, physical examination, blood sampling and patient questionnaires at multiple study visits over 2–3 years. Independent adjudication was performed on all mortalities and CV outcomes. Results Of 999 patients enrolled with clinically diagnosed HG, 750 (75%) initiated some form of TRT. Registry participants, including both treated and untreated patients, contributed 23 900 person-months (99.6% of the targeted) follow-up time. A total of 55 reported CV events occurred in 41 patients. Overall, five patients died of CV-related causes (3 on TRT, 2 untreated) and none of the deaths were adjudicated as treatment-related. The overall CV incidence rate was 1522 per 100 000 person-years. CV event rates for men receiving TRT were not statistically different from untreated men (P=.70). Regardless of treatment assignment, CV event rates were higher in older men and in those with increased CV risk factors or a prior history of CV events. Conclusions Age and prior CV history, not TRT use, were predictors of new-onset CV events in this multi-national, prospective hypogonadism registry
The assessment of vascular risk in men with erectile dysfunction: the role of the cardiologist and general physician.
Erectile dysfunction (ED) and cardiovascular disease (CVD) share risk factors and frequently coexist, with endothelial dysfunction believed to be the pathophysiologic link. ED is common, affecting more than 70% of men with known CVD. In addition, clinical studies have demonstrated that ED in men with no known CVD often precedes a CVD event by 2-5 years. ED severity has been correlated with increasing plaque burden in patients with coronary artery disease. ED is an independent marker of increased CVD risk including all-cause and especially CVD mortality, particularly in men aged 30-60 years. Thus, ED identifies a window of opportunity for CVD risk mitigation. We recommend that a thorough history, physical exam (including visceral adiposity), assessment of ED severity and duration and evaluation including fasting plasma glucose, lipids, resting electrocardiogram, family history, lifestyle factors, serum creatinine (estimated glomerular filtration rate) and albumin:creatinine ratio, and determination of the presence or absence of the metabolic syndrome be performed to characterise cardiovascular risk in all men with ED. Assessment of testosterone levels should also be considered and biomarkers may help to further quantify risk, even though their roles in development of CVD have not been firmly established. Finally, we recommend that a question about ED be included in assessment of CVD risk in all men and be added to CVD risk assessment guidelines
Multiple primary tumours in women following breast cancer, 1973–2000
We investigated the predictors of the risk of developing a second primary cancer after breast cancer, this occurring in about 12% of affected women. The analysis included 335 191 females, registered in the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database, who had been diagnosed with breast cancer. Observed numbers of subsequent cancers in the SEER database with a first breast cancer diagnosed from 1973 to 2000 were compared with the expected numbers based on age-adjusted incidence rates to calculate standardised incidence ratios. Kaplan–Meier curves were conducted to determine the median time until the second primary cancer diagnosis. Average number of years until diagnosis varied by site and by age as well as median years until second cancer diagnosis. Most cancer risks decreased with age, but there was an increase in aging-related cancers such as lung cancer. The median years of follow-up were well beyond the 5-year mark. Breast cancer survivors should be advised of their increased risk for developing certain cancers in their lifetime
Control of star formation by supersonic turbulence
Understanding the formation of stars in galaxies is central to much of modern
astrophysics. For several decades it has been thought that stellar birth is
primarily controlled by the interplay between gravity and magnetostatic
support, modulated by ambipolar diffusion. Recently, however, both
observational and numerical work has begun to suggest that support by
supersonic turbulence rather than magnetic fields controls star formation. In
this review we outline a new theory of star formation relying on the control by
turbulence. We demonstrate that although supersonic turbulence can provide
global support, it nevertheless produces density enhancements that allow local
collapse. Inefficient, isolated star formation is a hallmark of turbulent
support, while efficient, clustered star formation occurs in its absence. The
consequences of this theory are then explored for both local star formation and
galactic scale star formation. (ABSTRACT ABBREVIATED)Comment: Invited review for "Reviews of Modern Physics", 87 pages including 28
figures, in pres
Electronic patient self-assessment and management (SAM): a novel framework for cancer survivorship
<p>Abstract</p> <p>Background</p> <p>We propose a novel framework for management of cancer survivorship: electronic patient Self-Assessment and Management (SAM). SAM is a framework for transfer of information to and from patients in such a way as to increase both the patient's and the health care provider's understanding of the patient's progress, and to help ensure that patient care follows best practice.</p> <p>Methods</p> <p>Patients who participate in the SAM system are contacted by email at regular intervals and asked to complete validated questionnaires online. Patient responses on these questionnaires are then analyzed in order to provide patients with real-time, online information about their progress and to provide them with tailored and standardized medical advice. Patient-level data from the questionnaires are ported in real time to the patient's health care provider to be uploaded to clinic notes. An initial version of SAM has been developed at Memorial Sloan-Kettering Cancer Center (MSKCC) and the University of California, San Francisco (UCSF) for aiding the clinical management of patients after surgery for prostate cancer.</p> <p>Results</p> <p>Pilot testing at MSKCC and UCSF suggests that implementation of SAM systems are feasible, with no major problems with compliance (> 70% response rate) or security.</p> <p>Conclusion</p> <p>SAM is a conceptually simple framework for passing information to and from patients in such a way as to increase both the patient's and the health care provider's understanding of the patient's progress, and to help ensure that patient care follows best practice.</p
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