3,943 research outputs found

    Radiative Inflation and Dark Energy

    Full text link
    We propose a model based on radiative symmetry breaking that combines inflation with Dark Energy and is consistent with the WMAP 7-year regions. The radiative inflationary potential leads to the prediction of a spectral index 0.955 \lesssim n_S \lesssim 0.967 and a tensor to scalar ratio 0.142 \lesssim r \lesssim 0.186, both consistent with current data but testable by the Planck experiment. The radiative symmetry breaking close to the Planck scale gives rise to a pseudo Nambu-Goldstone boson with a gravitationally suppressed mass which can naturally play the role of a quintessence field responsible for Dark Energy. Finally, we present a possible extra dimensional scenario in which our model could be realised.Comment: 15 pages, 4 figures; v2: references added, appendix added, Section 5 slightly modified; content matches published versio

    Estimating the Effect of Recurrent Infectious Diseases on Nutritional Status: Sampling Frequency, Sample-size, and Bias

    Get PDF
    There is an ongoing interest in studying the effect of common recurrent infections and conditions, such as diarrhoea, respiratory infections, and fever, on the nutritional status of children at risk of malnutrition. Epidemiological studies exploring this association need to measure infections with sufficient accuracy to minimize bias in the effect estimates. A versatile model of common recurrent infections was used for exploring how many repeated measurements of disease are required to maximize the power and logistical efficiency of studies investigating the effect of infectious diseases on malnutrition without compromising the validity of the estimates. Depending on the prevalence and distribution of disease within a population, 15-30 repeat measurements per child over one year should be sufficient to provide unbiased estimates of the association between infections and nutritional status. Less-frequent measurements lead to a bias in the effect size towards zero, especially if disease is rare. In contrast, recall error can lead to exaggerated effect sizes. Recall periods of three days or shorter may be preferable compared to longer recall periods. The results showed that accurate estimation of the association between recurrent infections and nutritional status required closer follow-up of study participants than studies using recurrent infections as an outcome measure. The findings of the study provide guidance for choosing an appropriate sampling strategy to explore this association

    Overview of the Tevatron Collider Complex: Goals, Operations and Performance

    Full text link
    For more than two decades the Tevatron proton-antiproton collider was the centerpiece of the world's high energy physics program. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for numerous physics discoveries and for many technological breakthroughs. In this article we outline the historical background that led to the construction of the Tevatron Collider, the strategy applied to evolution of performance goals over the Tevatron's operational history, and briefly describe operations of each accelerator in the chain and achieved performance.Comment: Includes modifications suggested by reviewer

    On Your MARK, Get SET(D2), Go! H3K36me3 Primes DNA Mismatch Repair

    Get PDF
    Trimethylation of histone H3 on Lys36 (H3K36me3) by SETD2 is linked to actively transcribed regions. Li et al. identify a novel role for H3K36me3 that facilitates DNA mismatch repair (MMR) in cells by targeting the MMR machinery to chromatin during the cell cycle, thereby explaining certain cases of MMR-defective cancers

    Head Impact Magnitude in American High School Football

    Get PDF
    OBJECTIVES: To describe determinants of head impact magnitudes between various play aspects in high school football. METHODS: Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects (α = 0.05). RESULTS: The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P = .03); contact with another player (linear, rotational, HITsp: P < .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P < .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P < .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). CONCLUSIONS: Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered

    The Relationship of Personality Style and Attention Deficit Hyperactivity Disorder in Children

    Get PDF
    Introduction. This study was to identify personality correlates ofchildren with a diagnosis of Attention Deficit Hyperactive Disorder(ADHD). The Jungian Personality Type dimensions primarilyconsidered were Sensing/Intuiting and Perceiving/Judging.A Sensing child is likely to be very present-centered. A Perceivingchild tends to be curious and resist order and structure. Methods. Children attending a general pediatric clinic with a diagnosisof ADHD were eligible to participate. Enrolled childrenwere administered the Murphy-Meisgeier Type Indicator forChildren. Binomial tests were performed comparing Perceivingand Sensing personality components to accepted population rates. Results. Participants (n = 117) were predominantly male(78%) with a median age of 10 years. The Sensing trait (72%)was more prevalent than expected, though prevalence for thePerceiving trait (44%) did not differ from population rates. Conclusions. Personality types occasioned with the diagnosisof ADHD could be useful in establishing/normalizingtreatment regimens and approaches to assist thesechildren and their families better. KS J Med 2017;10(2):26-29

    Molecular Insights into Division of Single Human Cancer Cells in On-Chip Transparent Microtubes.

    Get PDF
    In vivo, mammalian cells proliferate within 3D environments consisting of numerous microcavities and channels, which contain a variety of chemical and physical cues. External environments often differ between normal and pathological states, such as the unique spatial constraints that metastasizing cancer cells experience as they circulate the vasculature through arterioles and narrow capillaries, where they can divide and acquire elongated cylindrical shapes. While metastatic tumors cause most cancer deaths, factors impacting early cancer cell proliferation inside the vasculature and those that can promote the formation of secondary tumors remain largely unknown. Prior studies investigating confined mitosis have mainly used 2D cell culture systems. Here, we mimic aspects of metastasizing tumor cells dividing inside blood capillaries by investigating single-cell divisions of living human cancer cells, trapped inside 3D rolled-up, transparent nanomembranes. We assess the molecular effects of tubular confinement on key mitotic features, using optical high- and super-resolution microscopy. Our experiments show that tubular confinement affects the morphology and dynamics of the mitotic spindle, chromosome arrangements, and the organization of the cell cortex. Moreover, we reveal that membrane blebbing and/or associated processes act as a potential genome-safety mechanism, limiting the extent of genomic instability caused by mitosis in confined circumstances, especially in tubular 3D microenvironments. Collectively, our study demonstrates the potential of rolled-up nanomembranes for gaining molecular insights into key cellular events occurring in tubular 3D microenvironments in vivo.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 311529 (S.S.) and the Volkswagen Foundation no. 86 362 (S.S. and W.X.), a FEBS Return-to-Europe fellowship (C.K.S.), the Wellcome Trust (092096/Z/10/Z for N.L.; 094587/Z/10/Z for R.B.), and a European Research Council (ERC) Starting Researcher Grant (R.E.C.-S.; SYSGRO). O.G.S. acknowledges financial support from the DFG Research Unit 1713 “Sensorische Mikro und Nanosysteme”. D.H.G. acknowledges funding from the Alexander von Humboldt Foundation and the U.S. National Science Foundation (Grants: CMMI 1200241 and CBET-1442014). Research in the S.P.J. laboratory is funded by Cancer Research U.K., the ERC, and the European Community Seventh Framework Programme (DDResponse), with core infrastructure provided by Cancer Research U.K. and the Wellcome Trust.This is the final version of the article. It first appeared from the American Chemical Society via http://dx.doi.org/10.1021/acsnano.6b0046

    Effect of Neighborhood Sanitation Coverage on Fecal Contamination of the Household Environment in Rural Bangladesh.

    Get PDF
    Enteric pathogens can be transmitted within the household and the surrounding neighborhood. The objective of this study was to understand the effect of neighborhood-level sanitation coverage on contamination of the household environment with levels of fecal indicator bacteria in rural Bangladesh. We conducted spot-check observations of sanitation facilities in neighboring households (NHs) within a 20-m radius of target households with children aged 6-24 months. Sanitation facilities were defined as improved (a private pit latrine with a slab or better) or unimproved. Fecal coliforms (FCs) on children's hands and sentinel toy balls were measured and used as indicators of household-level fecal contamination. We visited 1,784 NHs surrounding 428 target households. On average, sentinel toy balls had 2.11(standard deviation [SD] = 1.37) log10 colony-forming units (CFUs) of FCs/toy ball and children's hands had 2.23 (SD = 1.15) log10 CFU of FCs/two hands. Access to 100% private improved sanitation coverage in the neighborhood was associated with a small and statistically insignificant difference in contamination of sentinel toy balls (difference in means = -0.13 log10 CFU/toy ball; 95% confidence intervals [CI]: -0.64, 0.39; P = 0.63) and children's hands (difference in means = -0.11 log10 CFU/two hands; 95% CI: -0.53, 0.32; P = 0.62). Improved sanitation coverage in the neighborhood had limited measurable effect on FCs in the target household environment. Other factors such as access to improved sanitation in the household, absence of cow dung, presence of appropriate water drainage, and optimal handwashing practice may be more important in reducing FCs in the household environment
    • …
    corecore