862 research outputs found

    Dynamics of a Pair of Interacting Spins Coupled to an Environmental Sea

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    We solve for the dynamics of a pair of spins, coupled to each other and also to an environmental sea of oscillators. The environment mediates an indirect interaction between the spins, causing both mutual coherence effects and dissipation. This model describes a wide variety of physical systems, ranging from 2 coupled microscopic systems (eg., magnetic impurities, bromophores, etc), to 2 coupled macroscopic quantum systems. We obtain analytic results for 3 regimes, viz., (i) The locked regime, where the 2 spins lock together; (ii) The correlated relaxation regime (mutually correlated incoherent relaxation); and (iii) The mutual coherence regime, with correlated damped oscillations. These results cover most of the parameter space of the system.Comment: 49 pages, To appear in Int J. Mod. Phys.

    Broadband, unpolarized repumping and clearout light sources for Sr+^+ single-ion clocks

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    Future transportable optical clocks require compact and reliable light sources. Here, broadband, unpolarized repumper and state clearout sources for Sr+ single-ion optical clocks are reported. These turn-key devices require no frequency stabilization nor external modulators. They are fiber based, inexpensive, and compact. Key characteristics for clock operation are presented, including optical spectra, induced light shifts and required extinction ratios. Tests with an operating single-ion standard show a clearout efficiency of 100%. Compared to a laser-based repumper, the achievable fluorescence rates for ion detection are a few tens of per cent lower. The resulting ion kinetic temperature is 1--1.5 mK, near the Doppler limit of the ion system. Similar repumper light sources could be made for Ca+ (866 nm) and Ba+ (650 nm) using semiconductor gain media.Comment: 4 pages, 6 figure

    Framing Expectations in Early HIV Cure Research

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    Language used to describe clinical research represents a powerful opportunity to educate volunteers. In the case of HIV cure research there is an emerging need to manage expectations by using the term ‘experiment’. Cure experiments are proof-of-concept studies designed to evaluate novel paradigms to reduce persistent HIV-1 reservoirs, without any expectation of medical benefit

    Interface Equations for Capillary Rise in Random Environment

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    We consider the influence of quenched noise upon interface dynamics in 2D and 3D capillary rise with rough walls by using phase-field approach, where the local conservation of mass in the bulk is explicitly included. In the 2D case the disorder is assumed to be in the effective mobility coefficient, while in the 3D case we explicitly consider the influence of locally fluctuating geometry along a solid wall using a generalized curvilinear coordinate transformation. To obtain the equations of motion for meniscus and contact lines, we develop a systematic projection formalism which allows inclusion of disorder. Using this formalism, we derive linearized equations of motion for the meniscus and contact line variables, which become local in the Fourier space representation. These dispersion relations contain effective noise that is linearly proportional to the velocity. The deterministic parts of our dispersion relations agree with results obtained from other similar studies in the proper limits. However, the forms of the noise terms derived here are quantitatively different from the other studies

    A protocol for co-creating research project lay summaries with stakeholders:Guideline development for Canada's AGE-WELL Network

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    Background Funding bodies increasingly require researchers to write lay summaries to communicate projects’ real-world relevance to the public in an accessible way. However, research proposals and findings are generally not easily readable or understandable by non-specialist readers. Many researchers find writing lay summaries difficult because they typically write for fellow subject specialists or academics rather than the general public or a non-specialist audience. The primary objective of our project is to develop guidelines for researchers in Canada’s AGE-WELL Network of Centres of Excellence, and ultimately various other disciplines, sectors, and institutions, to co-create lay summaries of research projects with stakeholders. To begin, we produced a protocol for co-creating a lay summary based on workshops we organized and facilitated for an AGE-WELL researcher. This paper presents the lay summary co-creation protocol that AGE-WELL researchers will be invited to use. Methods Eligible participants in this project will be 24 AgeTech project researchers who are funded by the AGE-WELL network in its Core Research Program 2020. If they agree to participate in this project, we will invite them to use our protocol to co-produce a lay summary of their respective projects with stakeholders. The protocol comprises six steps: Investigate principles of writing a good lay summary, identify the target readership, identify stakeholders to collaborate with, recruit the identified stakeholders to work on a lay summary, prepare for workshop sessions, and execute the sessions. To help participants through the process, we will provide them with a guide to developing an accessible, readable research lay summary, help them make decisions, and host, and facilitate if needed, their lay summary co-creation workshops. Discussion Public-facing research outputs, including lay summaries, are increasingly important knowledge translation strategies to promote the impact of research on real-world issues. To produce lay summaries that include information that will interest a non-specialist readership and that are written in accessible language, stakeholder engagement is key. Furthermore, both researchers and stakeholders benefit by participating in the co-creation process. We hope the protocol helps researchers collaborate with stakeholders effectively to co-produce lay summaries that meet the needs of both the public and project funders

    Impact of dedicated women’s outreach workers (WOWs) on recruitment of women in ACTG clinical studies

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    Background: Despite efforts by the AIDS Clinical Trials Group (ACTG) to enroll representative numbers of diverse women, participation in ACTG studies in the United States remains largely white and male. To address this gap in women’s participation in ACTG research, a one-year pilot study of dedicated women’s outreach workers (WOWs) was proposed. Objectives: included demonstrating that targeted recruitment efforts can expand community awareness of ACTG research and ensuring successful enrollment of women at the respective clinical research sites. Methods: The pilot study was conducted at two U.S. sites (Rutgers New Jersey Medical School and Emory Ponce de Leon Center in Atlanta, Georgia). The WOWs worked with site personnel to identify and reach out to women living with HIV and/or Hepatitis B or C at their respective sites and encourage them to join a clinical trial registry for those interested in participating in future clinical trials. Results: The Rutgers WOW approached 127 potential participants (of whom 100 joined the WOW registry) and screened 35 participants for open ACTG studies. The Emory WOW approached 120 participants, enrolling 86 into the WOW registry, and screened 51 potential participants for open ACTG studies during the WOW’s tenure. The majority of women screened at both sites were women of color. Conclusions: The WOW study team identified several lessons learned that can inform future efforts to engage women living with HIV in clinical research. First, success in engaging women is proportional to level of funding and institutional support. Second, there is a need for a more gender-inclusive scientific agenda as women are more likely to participate if studies address topics of interest to them. Third, meaningful engagement is a two-way street

    The Stability of the Weak Skyrmions

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    We consider a set of gauge invariant terms in higher order effective Lagrangians of the strongly interacting scalar of the electroweak theory. The terms are introduced in the framework of the hidden gauge symmetry formalism. The usual gauge term is known to stabilize the skyrmion but only in the large vector mass limit. We find that adding higher-order gauge terms is insufficient to insure stability. We then proceed to analyze other gauge invariant interaction terms. Some of the conclusions also apply to QCD skyrmions.Comment: 3 pages, revtex v3, (optional), LAVAL-PHY-11-9

    Reasons People Living with HIV Might Prefer Oral Daily Antiretroviral Therapy, Long-Acting Formulations or Future HIV Remission Options

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    A growing body of research is beginning to elucidate reasons people living with HIV (PLWHIV) might prefer oral daily antiretroviral treatment (ART) compared with emerging long-acting ART (LA-ART) or HIV remission strategies under investigation. Our objective is to provide qualitative insights into the reasons why PLWHIV might prefer one of these HIV control therapies over others. From May to August 2018, we implemented a semistructured cross-sectional survey of PLWHIV in the United States to better understand patient preferences around various HIV treatment and remission options. Using free text, respondents were asked to explain why they preferred one HIV control option over the other two. We analyzed responses to the open-ended survey questions on reasons for preferring oral daily ART versus LA-ART versus HIV remission strategies using conventional content analysis. The results showed that PLWHIV preferred oral daily ART because of its familiarity and known safety and efficacy profile, whereas those who preferred LA-ART would value the convenience it offers. Finally, HIV remission strategies would be preferred to avoid taking ART altogether. The qualitative results provide insights into reasons why PLWHIV in the United States might prefer oral daily ART versus novel therapies. More importantly, they provide information to better align HIV virological control strategies with end-user perspectives. To make informed choices around evolving HIV therapeutics, PLWHIV and HIV care providers would benefit from decision tools to better assess options and trade-offs. More research is needed on how best to effectively support PLWHIV and HIV care providers in shared decision-making

    Post-Prior discrepancies in CDW-EIS calculations for ion impact ionization fully differential cross sections

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    In this work we present fully differential cross sections (FDCSs) calculations using post and prior version of CDW--EIS theory for helium single ionization by 100 MeV C6+^{6+} amu−1^{-1} and 3.6 MeV amu−1^{-1} Au24+^{24+} and Au53+^{53+} ions. We performed our calculations for different momentum transfer and ejected electron energies. The influence of internuclear potential on the ejected electron spectra is taken into account in all cases. We compare our calculations with absolute experimental measurements. It is shown that prior version calculations give better agreement with experiments in almost all studied cases.Comment: 9 pages, 7 figure

    Bond percolation on a class of correlated and clustered random graphs

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    We introduce a formalism for computing bond percolation properties of a class of correlated and clustered random graphs. This class of graphs is a generalization of the Configuration Model where nodes of different types are connected via different types of hyperedges, edges that can link more than 2 nodes. We argue that the multitype approach coupled with the use of clustered hyperedges can reproduce a wide spectrum of complex patterns, and thus enhances our capability to model real complex networks. As an illustration of this claim, we use our formalism to highlight unusual behaviors of the size and composition of the components (small and giant) in a synthetic, albeit realistic, social network.Comment: 16 pages and 4 figure
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