Tops and Writhing DNA

The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.Comment: 17 pages two figure

Calculations of the A_1 phonon frequency in photoexcited Tellurium

Calculations of the A_1 phonon frequency in photoexcited tellurium are presented. The phonon frequency as a function of photoexcited carrier density and phonon amplitude is determined. Recent pump probe experiments are interpreted in the light of these calculatons. It is proposed that, in conjunction with measurements of the phonon period in ultra-fast pump-probe reflectivity experiments, the calculated frequency shifts can be used to infer the evolution of the density of photoexcited carriers on a sub-picosecond time-scale.Comment: 15 pages Latex, 3 postscript figure

Trials

INTRODUCTION: The Ebola virus disease (EVD) outbreak in 2014-2016 in West Africa was the largest on record and provided an opportunity for large clinical trials and accelerated efforts to develop an effective and safe preventative vaccine. Multiple questions regarding the safety, immunogenicity, and efficacy of EVD vaccines remain unanswered. To address these gaps in the evidence base, the Partnership for Research on Ebola Vaccines (PREVAC) trial was designed. This paper describes the design, methods, and baseline results of the PREVAC trial and discusses challenges that led to different protocol amendments. METHODS: This is a randomized, double-blind, placebo-controlled phase 2 clinical trial of three vaccine strategies against the Ebola virus in healthy volunteers 1 year of age and above. The three vaccine strategies being studied are the rVSVΔG-ZEBOV-GP vaccine, with and without a booster dose at 56 days, and the Ad26.ZEBOV,MVA-FN-Filo vaccine regimen with Ad26.ZEBOV given as the first dose and the MVA-FN-Filo vaccination given 56 days later. There have been 4 versions of the protocol with those enrolled in Version 4.0 comprising the primary analysis cohort. The primary endpoint is based on the antibody titer against the Ebola virus surface glycoprotein measured 12 months following the final injection. RESULTS: From April 2017 to December 2018, a total of 5002 volunteers were screened and 4789 enrolled. Participants were enrolled at 6 sites in four countries (Guinea, Liberia, Sierra Leone, and Mali). Of the 4789 participants, 2560 (53%) were adults and 2229 (47%) were children. Those < 18 years of age included 549 (12%) aged 1 to 4 years, 750 (16%) 5 to 11 years, and 930 (19%) aged 12-17 years. At baseline, the median (25th, 75th percentile) antibody titer to Ebola virus glycoprotein for 1090 participants was 72 (50, 116) EU/mL. DISCUSSION: The PREVAC trial is evaluating-placebo-controlled-two promising Ebola candidate vaccines in advanced stages of development. The results will address unanswered questions related to short- and long-term safety and immunogenicity for three vaccine strategies in adults and children. TRIAL REGISTRATION: ClinicalTrials.gov NCT02876328 . Registered on 23 August 2016

Entrepreneurial-intention constraint model: A comparative analysis among post-graduate management students in India, Singapore and Malaysia

YesAlthough literature on entrepreneurship has increasingly focused on intention-based models, not much emphasis has been laid on understanding the combined effect of contextual and situational factors along with support of university environment on the formation of entrepreneurial intention among students. In an effort to make up for this shortfall, by taking Theory of Planned Behavior as basic framework, the present study seeks to understand the influence of three of the most important factors, viz. (a) endogenous barriers, (b) exogenous environment, and (c) university environment and support on the entrepreneurial intention among management students. The study sample consisted of 1,097 students, wherein 526 students were from India, 252 from Singapore, and 319 were from Malaysia. The results indicates that along with positive attitude and perceived behavioral control that directly influences entrepreneurial intention, university environment and support and exogenous environment also have an indirect but significant impact on shaping of entrepreneurial intention among students. With this, it was found that exogenous environment was found to have a negative relationship with both attitude towards behavior and perceived behavioral control for all three countries.The full-text of this article will be released for public view at the end of the publisher embargo on 2 Jun 2018

Interventions aimed at increasing research use in nursing: a systematic review

<p>Abstract</p> <p>Background</p> <p>There has been considerable interest recently in developing and evaluating interventions to increase research use by clinicians. However, most work has focused on medical practices; and nursing is not well represented in existing systematic reviews. The purpose of this article is to report findings from a systematic review of interventions aimed at increasing research use in nursing.</p> <p>Objective</p> <p>To assess the evidence on interventions aimed at increasing research use in nursing.</p> <p>Methods</p> <p>A systematic review of research use in nursing was conducted using databases (Medline, CINAHL, Healthstar, ERIC, Cochrane Central Register of Controlled Trials, and Psychinfo), grey literature, ancestry searching (Cochrane Database of Systematic Reviews), key informants, and manual searching of journals. Randomized controlled trials and controlled before- and after-studies were included if they included nurses, if the intervention was explicitly aimed at increasing research use or evidence-based practice, and if there was an explicit outcome to research use. Methodological quality was assessed using pre-existing tools. Data on interventions and outcomes were extracted and categorized using a pre-established taxonomy.</p> <p>Results</p> <p>Over 8,000 titles were screened. Three randomized controlled trials and one controlled before- and after-study met the inclusion criteria. The methodological quality of included studies was generally low. Three investigators evaluated single interventions. The most common intervention was education. Investigators measured research use using a combination of surveys (three studies) and compliance with guidelines (one study). Researcher-led educational meetings were ineffective in two studies. Educational meetings led by a local opinion leader (one study) and the formation of multidisciplinary committees (one study) were both effective at increasing research use.</p> <p>Conclusion</p> <p>Little is known about how to increase research use in nursing, and the evidence to support or refute specific interventions is inconclusive. To advance the field, we recommend that investigators: (1) use theoretically informed interventions to increase research use, (2) measure research use longitudinally using theoretically informed and psychometrically sound measures of research use, as well as, measuring patient outcomes relevant to the intervention, and (3) use more robust and methodologically sound study designs to evaluate interventions. If investigators aim to establish a link between using research and improved patient outcomes they must first identify those interventions that are effective at increasing research use.</p

Innate immunity against HIV: a priority target for HIV prevention research

This review summarizes recent advances and current gaps in understanding of innate immunity to human immunodeficiency virus (HIV) infection, and identifies key scientific priorities to enable application of this knowledge to the development of novel prevention strategies (vaccines and microbicides). It builds on productive discussion and new data arising out of a workshop on innate immunity against HIV held at the European Commission in Brussels, together with recent observations from the literature

Future effects of ozone on carbon sequestration and climate change policy using a global biogeochemical model

Author Posting. © The Authors, 2004. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Climatic Change 73 (2005): 345-373, doi:10.1007/s10584-005-6776-4.Exposure of plants to ozone inhibits photosynthesis and therefore reduces vegetation production and carbon sequestration. The reduced carbon storage would then require further reductions in fossil fuel emissions to meet a given CO2 concentration target, thereby increasing the cost of meeting the target. Simulations with the Terrestrial Ecosystem Model (TEM) for the historical period (1860-1995) show the largest damages occur in the Southeast and Midwestern regions of the United States, eastern Europe, and eastern China. The largest reductions in carbon storage for the period 1950-1995, 41%, occur in eastern Europe. Scenarios for the 21st century developed with the MIT Integrated Global Systems Model (IGSM) lead to even greater negative effects on carbon storage in the future. In some regions, current land carbon sinks become carbon sources, and this change leads to carbon sequestration decreases of up to 0.4 Pg C yr-1 due to damage in some regional ozone hot spots. With a climate policy, failing to consider the effects of ozone damage on carbon sequestration would raise the global costs over the next century of stabilizing atmospheric concentrations of CO2 equivalents at 550 ppm by 6 to 21%. Because stabilization at 550 ppm will reduce emission of other gases that cause ozone, these additional benefits are estimated to be between 5 and 25% of the cost of the climate policy. Tropospheric ozone effects on terrestrial ecosystems thus produce a surprisingly large feedback in estimating climate policy costs that, heretofore, has not been included in cost estimates.This study was funded by the Biocomplexity Program of the U.S. National Science Foundation (ATM-0120468), the Methods and Models for Integrated Assessment Program of the U.S. National Science Foundation (DEB-9711626) and the Earth Observing System Program of the U.S. National Aeronautics and Space Administration (NAG5-10135). The IGSM has been developed as part of the Joint Program on the Science and Policy of Global Change with the support of a government-industry partnership including in addition to the above the US Department of Energy (901214-HAR; DE-FG02-94ER61937; DE-FG0293ER61713), the US Environmental Protection Agency (X-827703-01-0; XA-83042801-0), the National Aeronautics and Atmospheric Administration (NA16GP2290) and a group of corporate sponsors from the United States, Japan, United Kingdom, Germany, France, and Norway

Visualizing Tree Structures in Genetic Programming

This paper presents methods to visualize the structure of trees that occur in genetic programming. These methods allow for the inspection of structure of entire trees even though several thousands of nodes may be involved. The methods also scale to allow for the inspection of structure for entire populations and for complete trials even though millions of nodes may be involved. Examples are given that demonstrate how this new way of “seeing” can afford a potentially rich way of understanding dynamics that underpin genetic programming. The examples indicate further studies that might be enabled by visualizing structure at these scales.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45620/1/10710_2005_Article_7621.pd