514 research outputs found

    Homi Jehangir Bhabha as a Knowledge Generating System: A Longitudinal Cognition Study

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    Quantitative analysis of the events of synchronous references in the research papers followed throughout the publishing career of an individual scientist revealed interesting highlights on the knowledge-generating-system. In the case study of Homi Jehangir Bhabha first quinquennium and fifth quinquennium of his research career had low Self-references; third quinquennium and fourth quinquennium had moderate Self-references; whereas second quinquennium had highest Self-references. The two major clusters of Self-references occurring during the second and third quinquennium were indicators of active periods of knowledgegenerating and faster communications

    Hesitancy for COVID-19 Vaccines and Its Implications for Routine Immunisation

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    Vaccine hesitancy is a continuum, conditional on confidence (on vaccine or healthcare authorities), complacency, structural or psychological constraints, calculation or evaluation, vaccination convenience, and aspects pertaining to collective responsibility. The present chapter documents hesitancy to COVID-19 vaccination; and elaborates on factors that contribute to both hesitancy (barriers and concerns) and acceptance (enablers) rates, disaggregated by populations. We also discuss the multimodal nature of the COVID-19 pandemic and its vaccine hesitancy-related implications on routine immunisation. The pandemic and related movement restrictions or other mitigation measures, partial or complete suspension of vaccination clinics or fear of COVID-19, stress, anxiety, and depression may have limited parents’ access to avail routine immunisation vaccines for their children. Also, the impact of COVID-19 vaccine hesitancy is not limited to pandemic vaccines but may continue to extend to routinely recommended vaccines

    Mouse prion protein polymorphism Phe-108/Val-189 affects the kinetics of fibril formation and the response to seeding: evidence for a two-step nucleation polymerization mechanism

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    Prion diseases are fatal neurodegenerative disorders associated with the polymerization of the cellular form of prion protein (PrP(C)) into an amyloidogenic β-sheet infectious form (PrP(Sc)). The sequence of host PrP is the major determinant of host prion disease susceptibility. In mice, the presence of allele a (Prnp(a), encoding the polymorphism Leu-108/Thr-189) or b (Prnp(b), Phe-108/Val-189) is associated with short or long incubation times, respectively, following infection with PrP(Sc). The molecular bases linking PrP sequence, infection susceptibility, and convertibility of PrP(C) into PrP(Sc) remain unclear. Here we show that recombinant PrP(a) and PrP(b) aggregate and respond to seeding differently in vitro. Our kinetic studies reveal differences during the nucleation phase of the aggregation process, where PrP(b) exhibits a longer lag phase that cannot be completely eliminated by seeding the reaction with preformed fibrils. Additionally, PrP(b) is more prone to propagate features of the seeds, as demonstrated by conformational stability and electron microscopy studies of the formed fibrils. We propose a model of polymerization to explain how the polymorphisms at positions 108 and 189 produce the phenotypes seen in vivo. This model also provides insight into phenomena such as species barrier and prion strain generation, two phenomena also influenced by the primary structure of PrP.FWN – Publicaties zonder aanstelling Universiteit Leide

    Use of Quadrupolar Nuclei for Quantum Information processing by Nuclear Magnetic Resonance: Implementation of a Quantum Algorithm

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    Physical implementation of Quantum Information Processing (QIP) by liquid-state Nuclear Magnetic Resonance (NMR), using weakly coupled spin-1/2 nuclei of a molecule, is well established. Nuclei with spin>>1/2 oriented in liquid crystalline matrices is another possibility. Such systems have multiple qubits per nuclei and large quadrupolar couplings resulting in well separated lines in the spectrum. So far, creation of pseudopure states and logic gates have been demonstrated in such systems using transition selective radio-frequency pulses. In this paper we report two novel developments. First, we implement a quantum algorithm which needs coherent superposition of states. Second, we use evolution under quadrupolar coupling to implement multi qubit gates. We implement Deutsch-Jozsa algorithm on a spin-3/2 (2 qubit) system. The controlled-not operation needed to implement this algorithm has been implemented here by evolution under the quadrupolar Hamiltonian. This method has been implemented for the first time in quadrupolar systems. Since the quadrupolar coupling is several orders of magnitude greater than the coupling in weakly coupled spin-1/2 nuclei, the gate time decreases, increasing the clock speed of the quantum computer.Comment: 16 pages, 3 figure

    Real and Virtual Compton Scattering off the Nucleon

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    A review is given of the very recent developments in the fields of real and virtual Compton scattering off the nucleon. Both real and virtual Compton scattering reactions are discussed at low outgoing photon energy where one accesses polarizabilities of the nucleon. The real Compton scattering at large momentum transfer is discussed which is asymptotically a tool to obtain information on the valence quark wave function of the nucleon. The rapid developments in deeply virtual Compton scattering and associated meson electroproduction reactions at high energy, high photon virtuality and small momentum transfer to the nucleon are discussed. A unified theoretical description of those processes has emerged over the last few years, which gives access to new, generalized parton distributions. The experimental status and perspectives in these fields are also discussed.Comment: 25 pages, 17 figure

    Are randomly grown graphs really random?

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    We analyze a minimal model of a growing network. At each time step, a new vertex is added; then, with probability delta, two vertices are chosen uniformly at random and joined by an undirected edge. This process is repeated for t time steps. In the limit of large t, the resulting graph displays surprisingly rich characteristics. In particular, a giant component emerges in an infinite-order phase transition at delta = 1/8. At the transition, the average component size jumps discontinuously but remains finite. In contrast, a static random graph with the same degree distribution exhibits a second-order phase transition at delta = 1/4, and the average component size diverges there. These dramatic differences between grown and static random graphs stem from a positive correlation between the degrees of connected vertices in the grown graph--older vertices tend to have higher degree, and to link with other high-degree vertices, merely by virtue of their age. We conclude that grown graphs, however randomly they are constructed, are fundamentally different from their static random graph counterparts.Comment: 8 pages, 5 figure

    Cost-effectiveness of closed incision negative pressure wound therapy in preventing surgical site infection among obese women giving birth by caesarean section: An economic evaluation (DRESSING trial)

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    First published: 18 May 2023. OnlinePublBackground: There is growing evidence regarding the potential of closed incision negative pressure wound therapy (ci-NPWT) to prevent surgical site infections (SSIs) in healing wounds by primary closure following a caesarean section (CS). Aim: To assess the cost-effectiveness of ci-NPWT compared to standard dressings for prevention of SSI in obese women giving birth by CS. Materials and Methods: Cost-effectiveness and cost-utility analyses from a health service perspective were undertaken alongside a multicentre pragmatic randomised controlled trial, which recruited women with a pre-pregnancy body mass index ≥30 kg/m2 giving birth by elective/semi-urgent CS who received ci-NPWT (n = 1017) or standard dressings (n = 1018). Resource use and health-related quality of life (SF-12v2) collected during admission and for four weeks post-discharge were used to derive costs and quality-adjusted life years (QALYs). Results: ci-NPWT was associated with AUD162(95162 (95%CI −170 to 494)highercostperpersonandanadditional494) higher cost per person and an additional 12 849 (95%CI −62138to62 138 to 133 378) per SSI avoided. There was no detectable difference in QALYs between groups; however, there are high levels of uncertainty around both cost and QALY estimates. There is a 20% likelihood that ci-NPWT would be considered cost-effective at a willingness-to- pay threshold of $50 000 per QALY. Per protocol and complete case analyses gave similar results, suggesting that findings are robust to protocol deviators and adjustments for missing data. Conclusions: ci-NPWT for the prevention of SSI in obese women undergoing CS is unlikely to be cost-effective in terms of health service resources and is currently unjustified for routine use for this purpose.Jennifer A. Whitty, Adam P. Wagner, Evelyn Kang, David Ellwood, Wendy Chaboyer, Sailesh Kumar, Vicki L. Clifton, Lukman Thalib and Brigid M. Gillespi

    The social predictors of paternal antenatal mental health and their associations with maternal mental health in the Queensland Family Cohort prospective study

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    OnlinePublAntenatal depression (AND) affects 1 in 10 fathers, potentially negatively impacting maternal mental health and well-being during and after the transition to parenthood. However, few studies have assessed the social predictors of paternal AND or their possible associations with maternal mental health. We analysed data from 180 couples participating in the Queensland Family Cohort longitudinal study. Both parents completed surveys measuring mental health, relationship quality, social support, and sleep quality at 24 weeks of pregnancy. Mothers also completed the same surveys 6 weeks’ postpartum. Antenatal depression, stress, and anxiety were highest among fathers reporting lower social support and higher sleep impairment. Maternal AND, stress, and anxiety were higher among mothers reporting higher physical pain and poor sleep quality. Postnatally, mothers reporting lower social support also reported higher depression, anxiety, stress, and psycho-social well-being. While there were no significant associations between AND among fathers and maternal antenatal or postnatal depression, an exploratory analysis revealed that mothers whose partners reported lower antenatal social support also reported lower postnatal social support and higher postnatal depression. Our findings highlight the importance of including data among fathers to achieve a whole family approach to well-being during the transition to parenthood.Barnaby J. W. Dixson, Danielle Borg, Kym M. Rae, Koa Whittingha, Brenda Gannon, Steven M. McPhail, Hannah E. Carter, Karen M. Moritz, Roslyn N. Boyd, Samudragupta Bora, Sailesh Kumar, Julanne Frater, Daniel Schweitzer, Paul Miller, Divya Mehter, Vicki L. Clifto

    Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV

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    We present a search for the production of neutral Higgs bosons decaying into tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into tautau pairs, and we then interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL
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