10 research outputs found
On continuum driven winds from rotating stars
We study the dynamics of continuum driven winds from rotating stars, and
develop an approximate analytical model. We then discuss the evolution of
stellar angular momentum, and show that just above the Eddington limit, the
winds are sufficiently concentrated towards the poles to spin up the star. A
twin-lobe structure of the ejected nebula is seen to be a generic consequence
of critical rotation. We find that if the pressure in such stars is
sufficiently dominated by radiation, an equatorial ejection of mass will occur
during eruptions. These results are then applied to {\eta}-Carinae. We show
that if it began its life with a high enough angular momentum, the present day
wind could have driven the star towards critical rotation, if it is the
dominant mode of mass loss. We find that the shape and size of the Homunculus
nebula, as given by our model, agree with recent observations. Moreover, the
contraction expected due to the sudden increase in luminosity at the onset of
the Great Eruption explains the equatorial "skirt" as well.Comment: 8 pages, 4 figure
QT interval dynamics in patients with ST-elevation MI
BackgroundAn association between excessively prolonged QT and ventricular arrhythmia in patients with ST-elevation myocardial infarction has been described; however, the QT dynamics, characterization, and long-term predictive value are not well known.ObjectiveTo characterize QT interval dynamics in patients undergoing ST elevation myocardial infarction (STEMI) and determine its association with mortality.MethodsA retrospective analysis of 4,936 consecutive patients, hospitalized for STEMI between 01/2013–12/2021. Patients with less than three electrocardiograms (ECGs) during index hospitalization were excluded. Baseline demographics, cardiovascular history, clinical risk factors, treatment measures, laboratory results, and mortality data were retrieved from the hospital’s electronic medical records.ResultsWe included 1,054 patients and 5,021 ECGs in our cohort with a median follow-up of 6 years [interquartile range (IQR) 4.3–7.4 years]. The QT was longer in women in comparison to men (428.6 ms ± 33.4 versus 419.8 ms ± 32.52, P-value = 0.001). QT prolongation was greater in females, elderly patients, and patients with STEMI caused by occlusion of the left anterior descending (LAD) coronary artery. We determined QT cutoff to be 445 ms. This value of QT divided our cohort upon arrival into a long QT group (217 patients, 26% of the cohort) and a “normal” QT group (835 patients, 74% of the cohort). The long QT group experienced an increase in combined short and long terms all-cause mortality. The QT upon arrival, on day 2 of hospitalization, and before discharge from the hospital, correlated with long-term mortality.ConclusionQT duration is often prolonged during STEMI; this prolongation is associated with increased mortality and adverse events. Gender is an important mediator of QT dynamics
On the Spectrum of Direct Gaugino Mediation
In direct gauge mediation, the gaugino masses are anomalously small, giving
rise to a split SUSY spectrum. Here we investigate the superpartner spectrum in
a minimal version of "direct gaugino mediation." We find that the sfermion
masses are comparable to those of the gauginos - even in the hybrid
gaugino-gauge mediation regime - if the messenger scale is sufficiently small.Comment: 21 pages, 4 figures; V2: refs. adde
A Light Stop with Flavor in Natural SUSY
The discovery of a SM-like Higgs boson near 125 GeV and the flavor texture of
the Standard Model motivate the investigation of supersymmetric quiver-like BSM
extensions. We study the properties of such a minimal class of models which
deals naturally with the SM parameters. Considering experimental bounds as well
as constraints from flavor physics and Electro-Weak Precision Data, we find the
following. In a self-contained minimal model - including the full dynamics of
the Higgs sector - top squarks below a TeV are in tension with b->s{\gamma}
constraints. Relaxing the assumption concerning the mass generation of the
heavy Higgses, we find that a stop not far from half a TeV is allowed. The
models have some unique properties, e.g. an enhancement of the h->
b\bar{b},\tau\bar{{\tau}} decays relative to the h->\gamma{\gamma} one, a
gluino about 3 times heavier than the stop, an inverted hierarchy of about 3-20
between the squarks of the first two generations and the stop, relatively light
Higgsino neutralino or stau NLSP, as well as heavy Higgses and a W' which may
be within reach of the LHC.Comment: LaTeX, 22 pages, 4 figures; V2: references adde
The Effect of the PCSK9 Inhibitor Evolocumab on Aldosterone Secretion among High Cardiovascular Risk Patients: A Pilot Study
Elevated low-density lipoprotein (LDL) cholesterol is one of the leading causes of cardiovascular disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors reduce LDL cholesterol levels with subsequent reductions in cardiovascular morbidity. Elevated aldosterone levels are also associated with a greater risk of cardiovascular morbidity. There are currently no published data on the impact of PCSK9 inhibitor monotherapy on the secretion of aldosterone. The aim of this study was to examine the effect of monotherapy with the PSCK9 inhibitor evolocumab on the lipid profile and aldosterone secretion level in high-risk cardiovascular patients. Lipid profile, sodium, potassium, aldosterone, cortisol, plasma renin activity, and adrenocorticotropic hormone (ACTH) levels were analyzed at baseline and after 3 months of evolocumab therapy. Each participant underwent a 250 mcg ACTH stimulation test upon study entry. Eight women and seven men were included in the study. Their median total cholesterol, LDL cholesterol, lipoprotein (a), apolipoprotein B100, and baseline and stimulated aldosterone levels were significantly lower after 3 months of evolocumab therapy. These heretofore unreported findings indicate that reductions in unstimulated and stimulated aldosterone secretion under evolocumab therapy could be associated with reductions in cardiovascular events, a possibility that warrants further investigation