594 research outputs found
Megathrust Stress Drop as Trigger of Aftershock Seismicity: Insights From the 2011 Tohoku Earthquake, Japan
Numerous normal-faulting aftershocks in subduction forearcs commonly follow large megathrust earthquakes. Postseismic normal faulting has been explained by stress changes induced by the stress drop along the megathrust. However, details of forearc stress changes and aftershock triggering mechanisms remain poorly understood. Here, we use numerical force-balance models combined with Coulomb failure analysis to show that the megathrust stress drop supports normal faulting, but that forearc-wide aftershock triggering is feasible within a narrow range of megathrust stress drop values and preseismic stress states only. We determine this range for the 2011 Tohoku earthquake (Japan) and show that the associated stress changes explain the aftershock seismicity in unprecedented detail and are consistent with the stress released by forearc seismicity before and after the earthquake
Characteristics, treatment and outcome of patients with non-ST-elevation acute coronary syndromes and multivessel coronary artery disease: observations from PURSUIT (Platelet Glycoprotein IIb/IIIa in unstable angina: receptor suppression using integreling therapy)
BACKGROUND: The 6-month clinical outcome of patients with multivessel disease enrolled in PURSUIT (Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy) is described. Patients with complete angiography data were included; multivessel disease was stratified according to the treatment strategy applied early during hospitalization, i.e. medical treatment, percutaneous coronary intervention (PCI) (balloon), PCI (stent), or coronary artery bypass grafting (CABG). METHODS: Patients were divided into three groups according to the treatment strategy applied during the first 30 days of enrolment. Patients who did not undergo a percutaneous or surgical coronary intervention were classified as medically treated. Patients who underwent a PCI (prior to a possible CABG) were separated from those who underwent a CABG (prior to a possible PCI). The PCI group was further subdivided: patients receiving >/=1 coronary stents were separated from those in whom no stents were used. RESULTS: The mortality rate at 30 days was 6.7, 3.9, 2.4 and 4.8% for the medical treatment, PCI (balloon), PCI (stent) and CABG groups, respectively (p value = 0.002). Differences as observed at 30 days were still present at 6-month follow-up with 11.1, 5.8, 5.5 and 6.5% mortality event rates for the aforementioned groups (p value = 0.002). The 30-day myocardial infarction (MI) rate according to the opinion of the Clinical Events Committee was lower among medically than non-medically treated patients, with the highest event rate observed in the CABG group (27.7%). Approximately half of the MIs in the PCI and CABG subgroups occurred within 48 h after the procedure. CONCLUSIONS: The observed differences in clinical outcomes are explained by an imbalance in baseline characteristics and comorbid conditions between the analyzed groups of patients
Stochastic Model for Surface Erosion Via Ion-Sputtering: Dynamical Evolution from Ripple Morphology to Rough Morphology
Surfaces eroded by ion-sputtering are sometimes observed to develop
morphologies which are either ripple (periodic), or rough (non-periodic). We
introduce a discrete stochastic model that allows us to interpret these
experimental observations within a unified framework. We find that a periodic
ripple morphology characterizes the initial stages of the evolution, whereas
the surface displays self-affine scaling in the later time regime. Further, we
argue that the stochastic continuum equation describing the surface height is a
noisy version of the Kuramoto-Sivashinsky equation.Comment: 4 pages, 7 postscript figs., Revtex, to appear in Phys. Rev. Let
Sustained ventricular arrhythmias among patients with acute coronary syndromes with no ST-segment elevation: incidence, predictors, and outcomes
BACKGROUND: The prognosis of ventricular arrhythmias among patients with non-ST-elevation acute coronary syndromes is unknown. We studied the incidence, predictors, and outcomes of sustained ventricular arrhythmias in 4 large randomized trials of such patients. METHODS AND RESULTS: We pooled the datasets of the Global Use of Streptokinase and tPA for Occluded Arteries (GUSTO)-IIb, Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT), Platelet IIb/IIIa Antagonism for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network (PARAGON)-A, and PARAGON-B trials (n=26 416). We identified independent predictors of ventricular fibrillation (VF) and ventricular tachycardia (VT) and compared the 30-day and 6-month mortality rates of patients who did (n=552) and did not (n=25 864) develop these arrhythmias during the index hospitalization. Independent predictors of in-hospital VF included prior hypertension, chronic obstructive pulmonary disease, prior myocardial infarction, and ST-segment changes at presentation. Except for hypertension, these variables also independently predicted in-hospital VT. In Cox proportional-hazards modeling, in-hospital VF and VT were independently associated with 30-day mortality (hazard ratio [HR], 23.2 [95% CI, 18.1 to 29.8] for VF and HR, 7.6 [95% CI, 5.5 to 10.4] for VT) and 6-month mortality (HR, 14.8 [95% CI, 12.1 to 18.3] for VF and HR, 5.0 [95% CI, 3.8 to 6.5] for VT). These differences remained significant after excluding patients with heart failure or cardiogenic shock and those who died <24 hours after enrollment. CONCLUSIONS: Despite the use of effective therapies for non-ST-elevation acute coronary syndromes, ventricular arrhythmias in this setting are associated with increased 30-day and 6-month mortality. More effective therapies are needed to improve the survival of patients with these arrhythmias
Stroke in Patients With Acute Coronary Syndromes: Incidence and Outcomes in the Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT) Trial
BACKGROUND: The incidence of stroke in patients with acute coronary
syndromes has not been clearly defined because few trials in this patient
population have been large enough to provide stable estimates of stroke
rates. METHODS AND RESULTS: We studied the 10 948 patients with acute
coronary syndromes without persistent ST-segment elevation who were
randomly assigned to placebo or the platelet glycoprotein IIb/IIIa
receptor inhibitor eptifibatide in the Platelet Glycoprotein IIb/IIIa in
Unstable Angina: Receptor Suppression Using Integrilin Therapy (PURSUIT)
trial to determine stroke rates, stroke types, clinical outcomes in
patients with stroke, and independent baseline clinical predictors for
nonhemorrhagic stroke. Stroke occurred in 79 (0.7%) patients, with 66
(0.6%) nonhemorrhagic, 6 intracranial hemorrhages, 3 cerebral infarctions
with hemorrhagic conversion, and 4 of uncertain cause. There were no
differences in stroke rates between patients who received placebo and
those assigned high-dose eptifibatide (odds ratios and 95% confidence
intervals 0.82 [0.59, 1.14] and 0.70 [0.49, 0.99], respectively). Of the
79 patients with stroke, 17 (22%) died within 30 days, and another 26
(32%) were disabled by hospital discharge or 30 days, whichever came
first. Higher heart rate was the most important baseline clinical
predictor of nonhemorrhagic stroke, followed by older age, prior anterior
myocardial infarction, prior stroke or transient ischemic attack, and
diabetes mellitus. These factors were used to develop a simple scoring
nomogram that can predict the risk of nonhemorrhagic stroke. CONCLUSIONS:
Stro
Creatine kinase-MB elevation after percutaneous coronary intervention predicts adverse outcomes in patients with acute coronary syndromes.
AIM: To study the relationship between outcomes and peak creatine kinase (CK)-MB levels after percutaneous coronary intervention (PCI) in patients with non-ST-segment elevation acute coronar
Dengue in Madeira Island
This is a preprint of a paper whose final and definite form will be published in the volume
Mathematics of Planet Earth that initiates the book series CIM Series in Mathematical Sciences
(CIM-MS) published by Springer. Submitted Oct/2013; Revised 16/July/2014 and 20/Sept/2014;
Accepted 28/Sept/2014.Dengue is a vector-borne disease and 40% of world population is at risk.
Dengue transcends international borders and can be found in tropical and subtropical
regions around the world, predominantly in urban and semi-urban areas. A
model for dengue disease transmission, composed by mutually-exclusive compartments
representing the human and vector dynamics, is presented in this study. The
data is from Madeira, a Portuguese island, where an unprecedented outbreak was
detected on October 2012. The aim of this work is to simulate the repercussions of
the control measures in the fight of the disease
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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