217 research outputs found

    Asymptotic failure distributions

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    AbstractWe consider a single device shock model in which the shocks arrive as a renewal process. We study the asymptotic shape of the failure distribution and find conditions on the renewal process and the ability of the device to survive shocks so that the failure distribution is asymptotically Increasing Failure Rate

    Graphic Flash: A Collaboration of Writing, Arts and Media

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    Graphic Flash is an interdisciplinary collaborative project involving almost 100 students at SUNY Oswego. The process begins with a flash fiction story produced by advanced creative writers. These narratives are given to students in digital illustration, filmmaking students, and music students who come up with their own artistic interpretations of the stories. All of the student artworks are then brought together into a single Graphic Flash application. The app, designed by SUNY Oswego students studying digital publication, creates a space for all of the different art forms to exist aesthetically together in one location. The interactivity of the app allows the audience to read stories or hear the authors read them; to view an illustration; to listen to music based on the narrative themes; to watch short films. The resultant experience invites the audience to experience the versatility and depth of a single artistic idea explored creatively through the prism of multiple artistic lenses. SUNY Oswego students representing the various disciplines involved in Graphic Flash will speak to their creative processes and the ways they introduced their personal vision into the shared practices. Discussion from panelists will likely also include topics like ekphrasis (art responding to art), adaptation, the role of professionalism in writing and the arts, the role of taste in collaborative work, and arts in the digital age

    Whistler Wave Cascade in Solar Wind Plasma

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    Nonlinear three dimensional, time dependent, fluid simulations of whistler wave turbulence are performed to investigate role of whistler waves in solar wind plasma turbulence in which characteristic turbulent fluctuations are characterized typically by the frequency and length scales that are respectively bigger than ion gyro frequency and smaller than ion gyro radius. The electron inertial length is an intrinsic length scale in whistler wave turbulence that distinguishably divides the high frequency solar wind turbulent spectra into scales smaller and bigger than the electron inertial length. Our simulations find that the dispersive whistler modes evolve entirely differently in the two regimes. While the dispersive whistler wave effects are stronger in the large scale regime, they do not influence the spectral cascades which are describable by a Kolmogorov-like k−7/3k^{-7/3} spectrum. By contrast, the small scale turbulent fluctuations exhibit a Navier-Stokes like evolution where characteristic turbulent eddies exhibit a typical k−5/3k^{-5/3} hydrodynamic turbulent spectrum. By virtue of equipartition between the wave velocity and magnetic fields, we quantify the role of whistler waves in the solar wind plasma fluctuations.Comment: Paper contains 3 figures. The paper is accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journa

    Acute nifedipine withdrawal: Consequences of preoperative and late cessation of therapy in patients with prior unstable angina

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    Reports of acute ischemic events after withdrawal of calcium antagonist therapy in outpatients and during bypass surgery in patients with prior angina at rest prompted the examination of the effect of nifedipine withdrawal in 81 patients who had completed a prospective, double-blind randomized trial of nifedipine versus placebo for rest angina. Thirty-nine patients underwent bypass surgery for uncontrolled angina or left main coronary artery disease. No significant difference between patients withdrawn from nifedipine or placebo was seen in the incidence of perioperative myocardial infarction, hypotension requiring intraaortic balloon counterpulsation, vasopressor or vasodilator requirements or incidence of significant arrhythmias.An additional 42 patients had completed 2 years on a protocol consisting of nitrates and propranolol in addition to nifedipine or placebo. During a mean of 66 hours of continuous monitoring after withdrawal of nifedipine or placebo, heart rate and blood pressure were unchanged. A worsening of previously present angina at rest occurred in five patients who had continued to experience rest angina before drug withdrawal, four of whom were withdrawn from nifedipine. No patient with class I to III angina experienced new onset of rest angina during drug withdrawal. No patient experienced myocardial infarction. There was no significant difference between patients withdrawn from nifedipine or placebo in the duration or frequency of ischemic ST changes on continuous electrocardiographic monitoring, or in duration or positive results of serial exercise treadmill testing.Thus, no early adverse effects of acute nifedipine withdrawal were found in patients with prior rest angina at the time of bypass surgery or in stable patients receiving long-term medical therapy. Patients with continued symptoms of rest angina, however, may experience adverse ischemic events with nifedipine withdrawal

    Spectral features of solar wind turbulent plasma

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    Spectral properties of a fully compressible solar wind Hall Magnetohydrodynamic plasma are investigated by means of time dependent three dimensional Hall MHD simulations. Our simulations, in agreement with spacecraft data, identify a spectral break in turbulence spectra at characteristic length-scales associated with electromagnetic fluctuations that are smaller than the ion gyroradius. In this regime, our 3D simulations show that turbulent spectral cascades in the presence of a mean magnetic field follow an omnidirectional anisotropic inertial range spectrum close to k−7/3k^{-7/3}. The onset of the spectral break in our simulations can be ascribed to the presence of nonlinear Hall interactions that modify the spectral cascades. Our simulations further show that the underlying charachteristic turbulent fluctuations are spectrally anisotropic, the extent of which depends critically on the local wavenumber. The fluctuations associated with length scales smaller than the ion gyroradius are highly compressible and tend to exhibit a near equipartition in the velocity and magnetic fields. Finally, we find that the orientation of velocity and magnetic field fluctuations critically determine the character of nonlinear interactions that predominantly govern a Hall MHD plasma, like the solar wind.Comment: This paper is accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journa

    Therapeutic effect of hyperbaric oxygen in psoriasis vulgaris: two case reports and a review of the literature

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    <p>Abstract</p> <p>Introduction</p> <p>Psoriasis is an inflammatory and immunological cutaneous disease. The high morbidity in patients with psoriasis results from severe clinical manifestations and/or adverse effects of treatment. The Undersea and Hyperbaric Medical Society and Federal Medicare and Medicaid Services have approved the use of hyperbaric oxygen (HBO<sub>2</sub>) for more than 15 indications, including wound healing, infections and late effects of radiation, which are largely unresponsive to conventional treatments. Accumulated data show that HBO<sub>2</sub> has anti-inflammatory effects and other positive influences on the immune system, making it a rational treatment in the management of psoriasis plaques and arthritis.</p> <p>Case presentation</p> <p>We present the cases of two patients with long histories of psoriasis vulgarus who exhibited marked improvement with use of HBO<sub>2.</sub> The first patient was 40 years old and had pustular psoriasis and psoriatic arthritis. He was treated with six sessions of HBO<sub>2</sub> (at 2.8 atmospheres of pressure for 60 minutes), which successfully controlled his symptoms. At the 18-month post-treatment follow up, the patient exhibited complete remission of psoriasis and marked improvement in psoriatic arthritis without medication. The second patient was 55 years old with extensive psoriatic lesions, and exhibited marked improvement within 15 sessions of HBO<sub>2</sub>. No adverse effects of HBO<sub>2</sub> were identified.</p> <p>Conclusions</p> <p>HBO<sub>2</sub> may possess potential therapeutic efficacy in the management of psoriasis. We outline the pathogenesis of psoriasis and the selective anti-inflammatory and immunosuppressive effects of HBO<sub>2</sub>. We hope that this will provide a basis for elucidating the mechanisms of action and consequently pave the way for further controlled studies.</p

    Estimates of the global burden of cervical cancer associated with HIV.

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    BACKGROUND: HIV enhances human papillomavirus (HPV)-induced carcinogenesis. However, the contribution of HIV to cervical cancer burden at a population level has not been quantified. We aimed to investigate cervical cancer risk among women living with HIV and to estimate the global cervical cancer burden associated with HIV. METHODS: We did a systematic literature search and meta-analysis of five databases (PubMed, Embase, Global Health [CABI.org], Web of Science, and Global Index Medicus) to identify studies analysing the association between HIV infection and cervical cancer. We estimated the pooled risk of cervical cancer among women living with HIV across four continents (Africa, Asia, Europe, and North America). The risk ratio (RR) was combined with country-specific UNAIDS estimates of HIV prevalence and GLOBOCAN 2018 estimates of cervical cancer to calculate the proportion of women living with HIV among women with cervical cancer and population attributable fractions and age-standardised incidence rates (ASIRs) of HIV-attributable cervical cancer. FINDINGS: 24 studies met our inclusion criteria, which included 236 127 women living with HIV. The pooled risk of cervical cancer was increased in women living with HIV (RR 6·07, 95% CI 4·40-8·37). Globally, 5·8% (95% CI 4·6-7·3) of new cervical cancer cases in 2018 (33 000 new cases, 95% CI 26 000-42 000) were diagnosed in women living with HIV and 4·9% (95% CI 3·6-6·4) were attributable to HIV infection (28 000 new cases, 20 000-36 000). The most affected regions were southern Africa and eastern Africa. In southern Africa, 63·8% (95% CI 58·9-68·1) of women with cervical cancer (9200 new cases, 95% CI 8500-9800) were living with HIV, as were 27·4% (23·7-31·7) of women in eastern Africa (14 000 new cases, 12 000-17 000). ASIRs of HIV-attributable cervical cancer were more than 20 per 100 000 in six countries, all in southern Africa and eastern Africa. INTERPRETATION: Women living with HIV have a significantly increased risk of cervical cancer. HPV vaccination and cervical cancer screening for women living with HIV are especially important for countries in southern Africa and eastern Africa, where a substantial HIV-attributable cervical cancer burden has added to the existing cervical cancer burden. FUNDING: WHO, US Agency for International Development, and US President's Emergency Plan for AIDS Relief

    Ischemia-Reperfusion Injury Leads to Distinct Temporal Cardiac Remodeling in Normal versus Diabetic Mice

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    Diabetes is associated with higher incidence of myocardial infarction (MI) and increased propensity for subsequent events post-MI. Here we conducted a temporal analysis of the influence of diabetes on cardiac dysfunction and remodeling after ischemia reperfusion (IR) injury in mice. Diabetes was induced using streptozotocin and IR performed by ligating the left anterior descending coronary artery for 30 min followed by reperfusion for up to 42 days. We first evaluated changes in cardiac function using echocardiography after 24 hours reperfusion and observed IR injury significantly decreased the systolic function, such as ejection fraction, fractional shortening and end systolic left ventricular volume (LVESV) in both control and diabetic mice. The longitudinal systolic and diastolic strain rate were altered after IR, but there were no significant differences between diabetic mice and controls. However, a reduced ability to metabolize glucose was observed in the diabetic animals as determined by PET-CT scanning using 2-deoxy-2-(18F)fluoro-D-glucose. Interestingly, after 24 hours reperfusion diabetic mice showed a reduced infarct size and less apoptosis indicated by TUNEL analysis in heart sections. This may be explained by increased levels of autophagy detected in diabetic mice hearts. Similar increases in IR-induced macrophage infiltration detected by CD68 staining indicated no change in inflammation between control and diabetic mice. Over time, control mice subjected to IR developed mild left ventricular dilation whereas diabetic mice exhibited a decrease in both end diastolic left ventricular volume and LVESV with a decreased intraventricular space and thicker left ventricular wall, indicating concentric hypertrophy. This was associated with marked increases in fibrosis, indicted by Masson trichrome staining, of heart sections in diabetic IR group. In summary, we demonstrate that diabetes principally influences distinct IR-induced chronic changes in cardiac function and remodeling, while a smaller infarct size and elevated levels of autophagy with similar cardiac function are observed in acute phase
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