92 research outputs found

    Electromagnetic Polarizabilities and Charge Radii of the Nucleons in the Diquark-model

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    The diquark model is used to calculate the electromagnetic polarizabilities and charge radii of the nucleons for three different potentials. Making the scalar diquark lower in mass introduces a mixing angle Ξ\theta between the ∣56⟩\left| 56\right\rangle and ∣70⟩\left| 70\right\rangle states ,which allows an improvement in value of all 6 properties. Generalizing the Gamov-Teller matrix and the magnetic moment operator to the diquark model gives constraints on this mixing. We obtain for the Richardson potential Ξ=23.2∘,\theta =23.2^{\circ }, α‟p=7.9−0.9+1.0×10−4fm3,\overline{\alpha }_p=7.9_{-0.9}^{+1.0}\times 10^{-4}fm^3, α‟n=7.7−0.6+0.3×10−4fm3,\overline{\alpha }_n=7.7_{-0.6}^{+0.3}\times 10^{-4}fm^3, ÎČ‟p=5.4−0.4+1.6×10−4fm3,\overline{\beta }_p=5.4_{-0.4}^{+1.6}\times 10^{-4}fm^3, ÎČ‟n=6.7−0.7+1.3×10−4fm3,\overline{\beta }% _n=6.7_{-0.7}^{+1.3}\times 10^{-4}fm^3, ⟹r2⟩p=0.37−0.03+0.02fm2,\left\langle r^2\right\rangle _p=0.37_{-0.03}^{+0.02}fm^2, ⟹r2⟩n=−0.07−0.02+0.03fm2.\left\langle r^2\right\rangle _n=-0.07_{-0.02}^{+0.03}fm^2. Additional pion cloud contributions could improve on all six results.Comment: 15 Pages, Latex, Figs on request, to be published Phys.Lett.B. Minor errors corrected and eqn 5,6,8,9 correcte

    Der Einfluss der LÀnge von BeobachtungszeitrÀumen auf die Identifizierung von Subgruppen in Online Communities

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    Die Verbreitung von Social Media und damit verbunden die entstehenden und wachsenden Communities im Internet fĂŒhren zu einer Zunahme von auswertbaren, digitalen Spuren, die hĂ€ufig öffentlich zugĂ€nglich sind. Diese lassen sich durch verschiedene analytische Verfahren wie z.B. die Methode der Sozialen Netzwerkanalyse [1] auswerten. Insbesondere AnsĂ€tze fĂŒr „Community Detection“ erfreuen sich besonderer Beliebtheit, wodurch sich unter anderem innovative Untergemeinschaften und Subgruppen beispielsweise in großen „Open Source“-Projekten identifizieren lassen [2]. Im Rahmen dieser Anwendungen ergeben sich neue methodische und grundlegende Fragen, darunter die nach der Rolle der von Zeit in solchen Analysen. WĂ€hrend die Darstellung dynamischer Effekte (z.B. durch Animationen) die Zeit als expliziten Parameter enthĂ€lt, geht die Wahl der Zeitintervalle fĂŒr die Aggregation von Daten, aus denen dann Netzwerke gewonnen werden, nur implizit in die PrĂ€missen des Verfahrens ein. Diese Effekte wurden im Gegensatz zur Analyse von Dynamik bisher kaum untersucht. Im Fall der Sozialen Netzwerkanalyse ist die ZielreprĂ€sentation selbst nicht mehr zeitbehaftet sondern sozusagen ein „statischer Schnappschuss“, wodurch etwa zeitabhĂ€ngige Interaktionsmuster nicht erkannt werden können. (...

    Community detection for access-control decisions: Analysing the role of homophily and information diffusion in Online Social Networks

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    Access-Control Lists (ACLs) (a.k.a. “friend lists”) are one of the most important privacy features of Online Social Networks (OSNs) as they allow users to restrict the audience of their publications. Nevertheless, creating and maintaining custom ACLs can introduce a high cognitive burden on average OSNs users since it normally requires assessing the trustworthiness of a large number of contacts. In principle, community detection algorithms can be leveraged to support the generation of ACLs by mapping a set of examples (i.e. contacts labelled as “untrusted”) to the emerging communities inside the user’s ego-network. However, unlike users’ access-control preferences, traditional community-detection algorithms do not take the homophily characteristics of such communities into account (i.e. attributes shared among members). Consequently, this strategy may lead to inaccurate ACL configurations and privacy breaches under certain homophily scenarios. This work investigates the use of community-detection algorithms for the automatic generation of ACLs in OSNs. Particularly, it analyses the performance of the aforementioned approach under different homophily conditions through a simulation model. Furthermore, since private information may reach the scope of untrusted recipients through the re-sharing affordances of OSNs, information diffusion processes are also modelled and taken explicitly into account. Altogether, the removal of gatekeeper nodes is further explored as a strategy to counteract unwanted data dissemination

    CMV Late Phase-Induced mTOR Activation Is Essential for Efficient Virus Replication in Polarized Human Macrophages : Antiviral Effects of mTOR Inhibitors

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    Human cytomegalovirus (CMV) remains one of the most important pathogens following solid-organ transplantation. Mounting evidence indicates that mammalian target of rapamycin (mTOR) inhibitors may decrease the incidence of CMV infection in solid- organ recipients. Here we aimed at elucidating the molecular mechanisms of this effect by employing a human CMV (HCMV) infection model in human macrophages, since myeloid cells are the principal in vivo targets of HCMV. We demonstrate a highly di- vergent host cell permissiveness for HCMV with opti- mal infection susceptibility in M2 but not M1 polarized macrophages. Employing an ultrahigh purified HCMV stock we observed rapamycin-independent viral entry and induction of IFN-b transcripts, but no proinflam- matory cytokines or mitogen-activated protein kinases and mTOR activation early after infection. However, in the late infection phase, sustained mTOR activa- tion was observed in HCMV-infected cells and was required for efficient viral protein synthesis including the viral late phase proteins pUL-44 and pp65. Accord- ingly, rapamycin strongly suppressed CMV replication 3 and 5 days postinfection in macrophages. In conclu- sion, these data indicate that mTOR is essential for virus replication during late phases of the viral cycle in myeloid cells and might explain the potent anti-CMV effects of mTOR inhibitors after organ transplantatio

    A randomized, placebo-controlled, double-blind, prospective trial to evaluate the effect of vildagliptin in new-onset diabetes mellitus after kidney transplantation

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    <p>Abstract</p> <p>Background</p> <p>New-onset diabetes mellitus after transplantation (NODAT), a frequent and serious complication after transplantation, is associated with decreased graft and patient survival. Currently, it is diagnosed and treated primarily according to existing guidelines for type II diabetes. To date, only a few trials have studied antidiabetic drugs in patients with NODAT. Vildagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor that improves pancreatic islet function by enhancing both α- and ÎČ-cell responsiveness to increased blood glucose. Experimental data show potential protective effects of DPP-4 inhibitors on islet function after exogenous stress stimuli including immunosuppressants. Therefore, the therapy of NODAT with this class of compounds seems attractive. At present, vildagliptin is used to treat type II diabetes as monotherapy or in combination with other antidiabetic drugs, since that it efficiently decreases glycated hemoglobin (HbA1c) values. Additionally, vildagliptin has been shown to be safe in patients with moderately impaired kidney function. This study will evaluate the safety and efficacy of vildagliptin monotherapy in renal transplant recipients with recently diagnosed NODAT.</p> <p>Methods/Design</p> <p>This study is a randomized, placebo-controlled, double-blind, prospective phase II trial. Using the results of routinely performed oral glucose tolerance tests (OGTT) in stable renal transplant patients at our center, we will recruit patients without a history of diabetes and a 2 h glucose value surpassing 200 mg/dl (11.1 mmol/l). They are randomized to receive either 50 mg vildagliptin or placebo once daily. A total of 32 patients with newly diagnosed NODAT will be included. The primary endpoint is the difference in the 2 h glucose value between baseline and the repeated OGTT performed 3 months after treatment start, compared between the vildagliptin- and the placebo-group. Secondary endpoints include changes in HbA1c and fasting plasma glucose (FPG). The safety of vildagliptin in renal transplant patients will be assessed by the number of symptomatic hypoglycemic episodes (glucose <72 mg/dl or 4 mmol/l), the number of adverse events, and possible medication-associated side-effects.</p> <p>Discussion</p> <p>NODAT is a severe complication after kidney transplantation. Few trials have assessed the safety and efficacy of antidiabetic drugs for these patients. The purpose of this study is to assess the safety and efficacy of vildagliptin in renal transplant patients with NODAT.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00980356</p

    Camostat Mesylate Versus Lopinavir/Ritonavir in Hospitalized Patients With COVID-19—Results From a Randomized, Controlled, Open Label, Platform Trial (ACOVACT)

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    Background: To date, no oral antiviral drug has proven to be beneficial in hospitalized patients with COVID-19.Methods: In this randomized, controlled, open-label, platform trial, we randomly assigned patients ≄18 years hospitalized with COVID-19 pneumonia to receive either camostat mesylate (CM) (considered standard-of-care) or lopinavir/ritonavir (LPV/RTV). The primary endpoint was time to sustained clinical improvement (≄48 h) of at least one point on the 7-category WHO scale. Secondary endpoints included length of stay (LOS), need for mechanical ventilation (MV) or death, and 29-day mortality.Results: 201 patients were included in the study (101 CM and 100 LPV/RTV) between 20 April 2020 and 14 May 2021. Mean age was 58.7 years, and 67% were male. The median time from symptom onset to randomization was 7 days (IQR 5–9). Patients in the CM group had a significantly shorter time to sustained clinical improvement (HR = 0.67, 95%-CI 0.49–0.90; 9 vs. 11 days, p = 0.008) and demonstrated less progression to MV or death [6/101 (5.9%) vs. 15/100 (15%), p = 0.036] and a shorter LOS (12 vs. 14 days, p = 0.023). A statistically nonsignificant trend toward a lower 29-day mortality in the CM group than the LPV/RTV group [2/101 (2%) vs. 7/100 (7%), p = 0.089] was observed.Conclusion: In patients hospitalized for COVID-19, the use of CM was associated with shorter time to clinical improvement, reduced need for MV or death, and shorter LOS than the use of LPV/RTV. Furthermore, research is needed to confirm the efficacy of CM in larger placebo-controlled trials.Systematic Review Registration: [https://clinicaltrials.gov/ct2/show/NCT04351724, https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001302-30/AT], identifier [NCT04351724, EUDRACT-NR: 2020–001302-30]
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