1,093 research outputs found

    On Universality in Human Correspondence Activity

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    Identifying and modeling patterns of human activity has important ramifications in applications ranging from predicting disease spread to optimizing resource allocation. Because of its relevance and availability, written correspondence provides a powerful proxy for studying human activity. One school of thought is that human correspondence is driven by responses to received correspondence, a view that requires distinct response mechanism to explain e-mail and letter correspondence observations. Here, we demonstrate that, like e-mail correspondence, the letter correspondence patterns of 16 writers, performers, politicians, and scientists are well-described by the circadian cycle, task repetition and changing communication needs. We confirm the universality of these mechanisms by properly rescaling letter and e-mail correspondence statistics to reveal their underlying similarity.Comment: 17 pages, 3 figures, 1 tabl

    Incorporation Of Deepwater Horizon Oil In A Terrestrial Bird

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    Carbon isotopic evidence revealed Deepwater Horizon (DWH) oil entering coastal planktonic and lower terrestrial food webs. The integration of spilled oil into higher terrestrial trophic levels, however, remains uncertain. Wemeasured radiocarbon (C-14) and stable carbon (C-13) in seaside sparrow (Ammodramus maritimus) feathers and crop contents. Lower C-14 and C-13 values in feathers and crop contents of birds from contaminated areas indicated incorporation of carbon from oil. Our results, although based on a small sample of birds, thus reveal a food-web link between oil exposure and a terrestrial ecosystem. They also suggest that the reduction in reproductive success previously documented in the same population might be due to the (direct) toxic effect of oil exposure, rather than to (indirect) ecological effects. Werecommend future studies test our results by using larger samples of birds from a wider area in order to assess the extent and implications ofDWHoil incorporation into the terrestrial food web

    The Concepts of Reliability and Homogeneity

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67956/2/10.1177_001316445001000103.pd

    Effects of Restoration of Blood Flow on the Development of Aortic Atherosclerosis in ApoE −/− Mice With Unilateral Renal Artery Stenosis

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    BACKGROUND: Chronic unilateral renal artery stenosis (RAS) causes accelerated atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice, but effects of restoration of renal blood flow on aortic atherosclerosis are unknown. METHODS AND RESULTS: Male ApoE(-/-) mice underwent sham surgery (n=16) or had partial ligation of the right renal artery (n=41) with the ligature being removed 4 days later (D4LR; n=6), 8 days later (D8LR; n=11), or left in place for 90 days (chronic RAS; n=24). Ligature removal at 4 or 8 days resulted in improved renal blood flow, decreased plasma angiotensin II levels, a return of systolic blood pressure to baseline, and increased plasma levels of neutrophil gelatinase associated lipocalin. Chronic RAS resulted in increased lipid staining in the aortic arch (33.2% [24.4, 47.5] vs 11.6% [6.1, 14.2]; P<0.05) and descending thoracic aorta (10.2% [6.4, 25.9] vs 4.9% [2.8, 7.8]; P<0.05), compared to sham surgery. There was an increased amount of aortic arch lipid staining in the D8LR group (22.7% [22.1, 32.7]), compared to sham-surgery, but less than observed with chronic RAS. Lipid staining in the aortic arch was not increased in the D4LR group, and lipid staining in the descending aorta was not increased in either the D8LR or D4LR groups. There was less macrophage expression in infrarenal aortic atheroma in the D4LR and D8LR groups compared to the chronic RAS group. CONCLUSIONS: Restoration of renal blood flow at either 4 or 8 days after unilateral RAS had a beneficial effect on systolic blood pressure, aortic lipid deposition, and atheroma inflammation

    Association of CYP2C19*17 Allele and Choice of P2Y12 Inhibitor on Cardiovascular Outcomes Following Percutaneous Coronary Intervention

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    Introduction: The CYP2C19*17 allele variant is a gain-of-function polymorphism which increases levels of the active metabolite of clopidogrel. Objective: *17 is associated with increased bleeding risk during clopidogrel therapy, but it is unclear whether alternative P2Y12 inhibitors, prasugrel and ticagrelor, produce better clinical outcomes in patients undergoing percutaneous coronary intervention (PCI). Methods: A single-center observational study was conducted in 928 PCI patients who received CYP2C19 testing and dual anti-platelet therapy (DAPT). Risk of major adverse cardiovascular or cerebrovascular events (MACCE) and clinically significant bleeding over 12 months were compared across genotype and DAPT groups by proportional hazards regression. Results: 584 patients were treated with clopidogrel while 344 patients had alternative therapy. In the clopidogrel group, 173 patients were hetero- or homozygous for *17 and 91 patients were hetero- or homozygous for a loss of function allele (LOF; *2 or *3). Patients treated with clopidogrel were older, more commonly female, and more likely to have hypertension, diabetes, and an acute coronary syndrome (ACS) than patients on alternative therapy. There were no differences in MACCE or clinically significant bleeding events in *17 patients treated with clopidogrel compared to alternative therapy in either the total population (p=0.54) or in ACS patients (p=0.98). Patients with LOF alleles were 3.4 times more likely in the total population (p \u3c0.0001) and 6.7 times more likely among ACS patients (p \u3c0.0001) to have MACCE if prescribed clopidogrel compared with alternative therapy. Discussion: *17 patients had equivalent clinical outcomes when treated with clopidogrel or alternative P2Y12 inhibitors

    Destabilization of the thermohaline circulation by transient perturbations to the hydrological cycle

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    We reconsider the problem of the stability of the thermohaline circulation as described by a two-dimensional Boussinesq model with mixed boundary conditions. We determine how the stability properties of the system depend on the intensity of the hydrological cycle. We define a two-dimensional parameters' space descriptive of the hydrology of the system and determine, by considering suitable quasi-static perturbations, a bounded region where multiple equilibria of the system are realized. We then focus on how the response of the system to finite-amplitude surface freshwater forcings depends on their rate of increase. We show that it is possible to define a robust separation between slow and fast regimes of forcing. Such separation is obtained by singling out an estimate of the critical growth rate for the anomalous forcing, which can be related to the characteristic advective time scale of the system.Comment: 37 pages, 8 figures, submitted to Clim. Dy

    A Semantic Framework for Enabling Radio Spectrum Policy Management and Evaluation

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    Because radio spectrum is a finite resource, its usage and sharing is regulated by government agencies. These agencies define policies to manage spectrum allocation and assignment across multiple organizations, systems, and devices. With more portions of the radio spectrum being licensed for commercial use, the importance of providing an increased level of automation when evaluating such policies becomes crucial for the efficiency and efficacy of spectrum management. We introduce our Dynamic Spectrum Access Policy Framework for supporting the United States government's mission to enable both federal and non-federal entities to compatibly utilize available spectrum. The DSA Policy Framework acts as a machine-readable policy repository providing policy management features and spectrum access request evaluation. The framework utilizes a novel policy representation using OWL and PROV-O along with a domain-specific reasoning implementation that mixes GeoSPARQL, OWL reasoning, and knowledge graph traversal to evaluate incoming spectrum access requests and explain how applicable policies were used. The framework is currently being used to support live, over-the-air field exercises involving a diverse set of federal and commercial radios, as a component of a prototype spectrum management system

    Activation of Protease-Activated Receptors 3 and 4 Accelerates Tissue Factor-Induced Thrombin Generation on the Surface of Vascular Smooth Muscle Cells

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    To determine factors regulating human aortic smooth muscle cells (HASMC) supported tissue factor-induced thrombin generation

    Acute ST-Elevation Myocardial Infarction in Patients Hospitalized for Noncardiac Conditions

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    BackgroundMajor advances have been made in the treatment of ST‐elevation myocardial infarction (STEMI) in outpatients. In contrast, little is known about outcomes in STEMI that occur in patients hospitalized for a noncardiac condition.Methods and ResultsThis was a retrospective, single‐center study of inpatient STEMIs from January 1, 2007, to July 31, 2011. Forty‐eight cases were confirmed to be inpatient STEMIs of a total of 139 410 adult discharges. These patients were older and more often female and had higher rates of chronic kidney disease and prior cerebrovascular events compared with 227 patients with outpatient STEMIs treated during the same period. Onset of inpatient STEMI was heralded most frequently by a change in clinical status (60%) and less commonly by patient complaints (33%) or changes on telemetry. Coronary angiography and percutaneous coronary intervention were performed in 71% and 56% of patients, respectively. The median time to obtain ECG (41 [10, 600] versus 5 [2, 10] minutes; P<0.001), ECG to angiography time (91 [26, 209] versus 35 [25, 46] minutes; P<0.001) and ECG to first device activation (FDA) (129 [65, 25] versus 60 [47, 76] minutes; P<0.001) were longer for inpatient versus outpatient STEMI. Survival to discharge was lower for inpatient STEMI (60% versus 96%; P<0.001), and this difference persisted after adjusting for potential confounders.ConclusionsPatients who develop a STEMI while hospitalized for a noncardiac condition are older and more often female, have more comorbidities, have longer ECG‐to‐FDA times, and are less likely to survive than patients with an outpatient STEMI

    Dominant-Negative Loss of PPAR  Function Enhances Smooth Muscle Cell Proliferation, Migration, and Vascular Remodeling

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    The Peroxisome Proliferator Activated Receptor-gamma (PPARÎł) protein is a nuclear transcriptional activator with importance in diabetes management as the molecular target for the thiazolidinedione (TZD) family of drugs. Substantial evidence indicates that the TZD family of PPARÎł agonists may retard the development of atherosclerosis. However, recent clinical data has suggested that at least one TZD may increase the risk of myocardial infarction and death from cardiovascular disease. In this study, we used a genetic approach to disrupt PPARÎł signaling to probe the protein's role in smooth muscle cell (SMC) responses that are important for atherosclerosis
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