1,734 research outputs found
Detections and Constraints on White Dwarf Variability from Time-Series GALEX Observations
We search for photometric variability in more than 23,000 known and candidate
white dwarfs, the largest ultraviolet survey compiled for a single study of
white dwarfs. We use gPhoton, a publicly available calibration/reduction
pipeline, to generate time-series photometry of white dwarfs observed by GALEX.
By implementing a system of weighted metrics, we select sources with
variability due to pulsations and eclipses. Although GALEX observations have
short baselines (< 30 min), we identify intrinsic variability in sources as
faint as Gaia G = 20 mag. With our ranking algorithm, we identify 49 new
variable white dwarfs (WDs) in archival GALEX observations. We detect 41 new
pulsators: 37 have hydrogen-dominated atmospheres (DAVs), including one
possible massive DAV, and four are helium-dominated pulsators (DBVs). We also
detect eight new eclipsing systems; five are new discoveries, and three were
previously known spectroscopic binaries. We perform synthetic injections of the
light curve of WD 1145+017, a system with known transiting debris, to test our
ability to recover similar systems. We find that the 3{\sigma} maximum
occurrence rate of WD 1145+017-like transiting objects is < 0.5%.Comment: 17 pages, 13 figure
Current concepts on coronary revascularization in diabetic patients
Diabetic mellitus (DM) patients with coronary artery disease (CAD) are at higher risk of cardiovascular events compared with non-DM individuals. While aggressive cardiovascular prevention and adequate blood glucose control remain cornerstones of therapy, the decision when and how to proceed to coronary revascularization in an individual DM patient should be based on the extent of CAD, ischaemic burden, ventricular function, as well as comorbidities. While in patients with stable symptoms, moderate CAD on coronary angiography and preserved left ventricular function a conservative strategy may be a valuable initial strategy, in patients with acute coronary syndromes (ACS) an early invasive approach should be favoured. The revascularization strategy for DM patients with complex multivessel CAD should be discussed within a heart team consisting of cardiologists, cardiac surgeons, and anaesthesiologists. In general, the threshold for coronary artery bypass surgery (CABG) should be lower for DM than for non-DM individuals. In patients undergoing percutaneous coronary intervention, the use of drug-eluting stents (DES) and—in the setting of ACS—of potent platelet inhibitors, such as prasugrel or ticagrelor, should be favoured. In the near future, multiple strategies may further favourably impact the prognosis of DM patients undergoing coronary revascularization. These include alternative antiplatelet agents such as thromboxane receptor inhibitors, the broad use of second generation DES, and possibly the implantation of bioresorbable stents. Coronary artery bypass surgery outcomes may also further improve by wide implementation of arterial revascularization, reduction in perioperative stroke by avoiding clamping of the aorta, reduction in wound infection by minimally invasive techniques, and optimization of post-operative medical managemen
Pan-urologic cancer genomic subtypes that transcend tissue of origin
AbstractUrologic cancers include cancers of the bladder, kidney, prostate, and testes, with common molecular features spanning different types. Here, we show that 1954 urologic cancers can be classified into nine major genomic subtypes, on the basis of multidimensional and comprehensive molecular characterization (including DNA methylation and copy number, and RNA and protein expression). Tissue dominant effects are first removed computationally in order to define these subtypes, which reveal common processes—reflecting in part tumor microenvironmental influences—driving cellular behavior across tumor lineages. Six of the subtypes feature a mixture of represented cancer types as defined by tissue or cell of origin. Differences in patient survival and in the manifestation of specific pathways—including hypoxia, metabolism, NRF2-ARE, Hippo, and immune checkpoint—can further distinguish the subtypes. Immune checkpoint markers and molecular signatures of macrophages and T cell infiltrates are relatively high within distinct subsets of each cancer type studied. The pan-urologic cancer genomic subtypes would facilitate information sharing involving therapeutic implications between tissue-oriented domains.</jats:p
Transesophageal Echocardiographically-Confirmed Pulmonary Vein Thrombosis in Association with Posterior Circulation Infarction
Pulmonary venous thromboembolism has only been identified as a cause of stroke with pulmonary arteriovenous malformations/fistulae, pulmonary neoplasia, transplantation or lobectomy, and following percutaneous radiofrequency ablation of pulmonary vein ostia in patients with atrial fibrillation. A 59-year-old man presented with a posterior circulation ischemic stroke. ‘Unheralded’ pulmonary vein thrombosis was identified on transesophageal echocardiography as the likely etiology. He had no further cerebrovascular events after intensifying antithrombotic therapy. Twenty-eight months after initial presentation, he was diagnosed with metastatic pancreatic adenocarcinoma and died 3 months later. This report illustrates the importance of doing transesophageal echocardiography in presumed ‘cardioembolic’ stroke, and that potential ‘pulmonary venous thromboembolic’ stroke may occur in patients without traditional risk factors for venous thromboembolism. Consideration should be given to screening such patients for occult malignancy
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Making the Economic Case for Small-Scale Distributed Wind -- A Screening for Distributed Generation Wind Opportunities: Preprint
This study was an offshoot of a previous assessment, which examined the potential for large-scale, greater than 50 MW, wind development on occupied federal agency lands. The study did not find significant commercial wind development opportunities, primarily because of poor wind resource on available and appropriately sized land areas or land use or aesthetic concerns. The few sites that could accommodate a large wind farm failed to have transmission lines in optimum locations required to generate power at competitive wholesale prices. The study did identify a promising but less common distributed generation (DG) development option. This follow-up study documents the NREL/Global Energy Concepts team efforts to identify economic DG wind projects at a select group of occupied federal sites. It employs a screening strategy based on project economics that go beyond quantity of windy land to include state and utility incentives as well as the value of avoided power purchases. It attempts to account for the extra costs and difficulties associated with small projects through the use of project scenarios that are more compatible with federal facilities and existing land uses. These benefits and barriers of DG are discussed, and the screening methodology and results are included. The report concludes with generalizations about the screening method and recommendations for improvement and other potential applications for this methodology
Charmed quark component of the photon wave function
We determine the c-anti-c component of the photon wave function on the basis
of (i) the data on the transitions e+ e- -> J/psi(3096), psi(3686), psi(4040),
psi(4415), (ii) partial widths of the two-photon decays eta_{c0}(2979),
chi_{c0}(3415), chi_{c2}(3556) -> gamma-gamma, and (iii) wave functions of the
charmonium states obtained by solving the Bethe-Salpeter equation for the
c-anti-c system. Using the obtained c-anti-c component of the photon wave
function we calculate the gamma-gamma decay partial widths for radial
excitation 2S state, eta_{c0}(3594) -> gamma-gamma, and 2P states
chi_{c0}(3849), chi_{c2}(3950) -> gamma-gamma.Comment: 20 pages, 8 figure
Long-term efficacy and safety results of taliglucerase alfa through 5years in adult treatment-naïve patients with Gaucher disease
Taliglucerase alfa, the first available plant cell-expressed recombinant therapeutic protein, is an enzyme replacement therapy approved for Gaucher disease (GD). PB-06-001, a pivotal phase 3, multicenter, randomized, double-blind, parallel-dose study investigated taliglucerase alfa 30 or 60U/kg every other week through 9months in treatment-naïve adults with GD; 30-month extension study PB-06-003 followed. Patients completing PB-06-001 and PB-06-003 could continue treatment in PB-06-007. Nineteen patients enrolled in PB-06-007 (30U/kg, n=8; 60U/kg, n=9; dose adjusted, n=2); 17 completed 5 total years of treatment. In these 3 groups, respectively, taliglucerase alfa resulted in mean decreases in spleen volume (-8.7, -6.9, -12.4 multiples of normal), liver volume (-0.6, -0.4, -0.5 multiples of normal), chitotriosidase activity (-83.1%, -93.4%, -87.9%), and chemokine (CC motif) ligand 18 concentration (-66.7%, -83.3%, -78.9%), as well as mean increases in hemoglobin concentration (+2.1, +2.1, +1.8mg/dL) and platelet count (+31,871, +106,800, +34,000/mm3). The most common adverse events were nasopharyngitis and arthralgia. Most adverse events were mild/moderate; no serious adverse events were considered treatment-related. These results demonstrate continued improvement of disease parameters during 5years of taliglucerase alfa therapy in 17 treatment-naive patients with no new safety concerns, extending the taliglucerase alfa clinical efficacy and safety dataset. This study was registered at www.clinicaltrials.gov as NCT01422187
Fragmentation production of doubly heavy baryons
Baryons with a single heavy quark are being studied experimentally at
present. Baryons with two units of heavy flavor will be abundantly produced not
only at future colliders, but also at existing facilities. In this paper we
study the production via heavy quark fragmentation of baryons containing two
heavy quarks at the Tevatron, the LHC, HERA, and the NLC. The production rate
is woefully small at HERA and at the NLC, but significant at and
machines. We present distributions in various kinematical variables
in addition to the integrated cross sections at hadron colliders.Comment: 13 pages, macro package epsfig needed, 6 .eps figure files in a
separate uuencoded, compressed and tarred file; complete paper available at
http://www.physics.carleton.ca/~mad/papers/paper.p
Fitting ODE models of tear film breakup
Several elements are developed to quantitatively determine the contribution
of different physical and chemical effects to tear breakup (TBU) in normal
subjects. Fluorescence (FL) imaging is employed to visualize the tear film and
to determine tear film (TF) thinning and potential TBU. An automated system
using a convolutional neural network was trained and deployed to identify
multiple TBU instances in each trial. Once identified, extracted FL intensity
data was fit by mathematical models that included tangential flow along the
eye, evaporation, osmosis and FL intensity of emission from the tear film.
Optimizing the fit of the models to the FL intensity data determined the
mechanism(s) driving each instance of TBU and produced an estimate of the
osmolarity within TBU. Initial estimates for FL concentration and initial TF
thickness agree well with prior results. Fits were produced for
instances of potential TBU from 15 normal subjects. The results showed a
distribution of causes of TBU in these normal subjects, as reflected by
estimated flow and evaporation rates, which appear to agree well with
previously published data. Final osmolarity depended strongly on the TBU
mechanism, generally increasing with evaporation rate but complicated by the
dependence on flow. The method has the potential to classify TBU instances
based on the mechanism and dynamics and to estimate the final osmolarity at the
TBU locus. The results suggest that it might be possible to classify individual
subjects and provide a baseline for comparison and potential classification of
dry eye disease subjects
Photon-Photon and Pomeron-Pomeron Processes in Peripheral Heavy Ion Collisions
We estimate the cross sections for the production of resonances, pion pairs
and a central cluster of hadrons in peripheral heavy-ion collisions through
two-photon and double-pomeron exchange, at energies that will be available at
RHIC and LHC. The effect of the impact parameter in the diffractive reactions
is introduced, and imposing the condition for realistic peripheral collisions
we verify that in the case of very heavy ions the pomeron-pomeron contribution
is indeed smaller than the electromagnetic one. However, they give a
non-negligible background in the collision of light ions. This diffractive
background will be more important at RHIC than at LHC.Comment: 22 pages, 1 Postscript figures, 4 tables, to appear in Phys. Rev.
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