1,894 research outputs found

    Top polarisation studies in HtH^-t and WtWt production

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    The polarisation of top quarks produced in high energy processes can be a very sensitive probe of physics beyond the Standard Model. The kinematical distributions of the decay products of the top quark can provide clean information on the polarisation of the produced top and thus can probe new physics effects in the top quark sector. We study some of the recently proposed polarisation observables involving the decay products of the top quark in the context of HtH^-t and WtWt production. We show that the effect of the top polarisation on the decay lepton azimuthal angle distribution, studied recently for these processes at leading order in QCD, is robust with respect to the inclusion of next-to-leading order and parton shower corrections. We also consider the leptonic polar angle, as well as recently proposed energy-related distributions of the top decay products. We construct asymmetry parameters from these observables, which can be used to distinguish the new physics signal from the WtWt background and discriminate between different values of tanβ\tan\beta and mHm_{H^-} in a general type II two-Higgs doublet model. Finally, we show that similar observables may be useful in separating a Standard Model WtWt signal from the much larger QCD induced top pair production background.Comment: 33 pages, 35 figures, references adde

    Model evaluation of target product profiles of an infant vaccine against respiratory syncytial virus (RSV) in a developed country setting

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    Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract disease in children worldwide and is a significant cause of hospital admissions in young children in England. No RSV vaccine has been licensed but a number are under development. In this work, we present two structurally distinct mathematical models, parameterized using RSV data from the UK, which have been used to explore the effect of introducing an RSV paediatric vaccine to the National programme. We have explored different vaccine properties, and dosing regimens combined with a range of implementation strategies for RSV control. The results suggest that vaccine properties that confer indirect protection have the greatest effect in reducing the burden of disease in children under 5 years. The findings are reinforced by the concurrence of predictions from the two models with very different epidemiological structure. The approach described has general application in evaluating vaccine target product profiles

    Maize Provisioning of Ontario Late Woodland Turkeys: Isotopic Evidence of Seasonal, Cultural, Spatial and Temporal Variation

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    The isotopic composition (δ13C, δ15N) of bone collagen from Ontario Late Woodland archaeological turkeys was compared with that of modern Ontario wild turkeys, and archaeological turkeys from American Southwestern, Mexican and other Woodland sites to determine whether Late Woodland Ontario peoples managed wild turkeys by provisioning them with maize, the only isotopically distinct horticultural plant at that time. Despite the fact that humans from Late Woodland Western Basin and Iroquoian traditions consumed equal amounts of maize, wild turkeys utilized by the two groups exhibit different diets. Western Basin turkeys reflect a C3-only diet, whereas Iroquoian turkeys were consuming significant quantities of maize (a C4 plant). Both groups of archaeological turkey consumed less maize than modern wild turkeys with access to waste left in fields by mechanized agriculture, but because ancient crop yields were much lower, we suggest that Iroquoian turkeys must have been provisioned, probably to create a reliable and nearby hunting niche (Linares 1976). Archaeological and isotopic evidence supports ethnohistoric accounts that turkeys were hunted after the fall harvest. Iroquoian archaeological turkey diets, in general, reflect the seasonal consumption of maize that would have been created by cold weather maize provisioning, with the major exception of one turkey from an Attawandaron (Neutral) site that appears to have been fed maize year round. Motivations for provisioning by Middle Ontario Iroquoian people likely included climate change and ritual/ceremonial activity as well as a reliable food supply. Because Iroquoian women controlled the harvest, it is likely that they were instrumental in altering this human/animal interaction, creating a position on the wild/domesticated continuum that is unique in the North American archaeological literature

    Imaging and spectroscopy of galaxies associated with two z~0.7 damped Lyman-alpha absorption systems

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    We have identified galaxies near two quasars which are at the redshift of damped Lyman-alpha (DLA) systems in the UV spectra of the quasars. Both galaxies are actively forming stars. One galaxy has a luminosity close to the break in the local galaxy luminosity function, L*, the other is significantly fainter than L* and appears to be interacting with a nearby companion. Despite the strong selection effects favoring spectroscopic identification of the most luminous DLA galaxies, many of the spectroscopically-identified DLA galaxies in the literature are sub-L*, suggesting that the majority of the DLA population is probably sub-L*, in contrast to MgII absorbers at similar redshifts whose mean luminosity is close to L*.Comment: 9 pages, to appear in AJ, November 2003 issu

    Teens Implementing a Childhood Obesity Prevention Program in the Community: Feasibility and Perceptions of a Partnership with HSTA and iCook 4-H.

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    High school student researchers and teen leaders from the Health Science Technology Academy (HSTA), under the supervision of HSTA teachers, led a childhood obesity prevention (COP) program (iCook 4-H). The objective was to evaluate the feasibility and perceptions of having teen leaders implement a COP program for dyads of youth (9⁻10 years old) and their primary adult food preparer. Behavior change and perceptions were assessed through surveys and open-ended interviews. Across eight HSTA organizations, 43 teen leaders participated in teaching the iCook 4-H program to 24 dyads. Increased frequency of culinary skills, physical activity and mealtime behavior were reported by youth. Almost all adults (93%) reported that their youth had learned kitchen skills and that the program provided youth-adult quality time and developed culinary skills. Youth echoed adult perceptions with additional themes of food safety and physical activity. HSTA teen leaders perceived the program to be successful and reported the training they received to implement the program was adequate 98% of the time. HSTA teachers found the program to be beneficial for HSTA students in improving leadership, confidence and responsibility. iCook 4-H was feasible to be disseminated through teen leaders in the HSTA program. This teen-led approach could serve as a model for youth health-related programming

    Teens Implementing a Childhood Obesity Prevention Program in the Community: Feasibility and Perceptions of a Partnership with HSTA and iCook 4-H

    Get PDF
    High school student researchers and teen leaders from the Health Science Technology Academy (HSTA), under the supervision of HSTA teachers, led a childhood obesity prevention (COP) program (iCook 4-H). The objective was to evaluate the feasibility and perceptions of having teen leaders implement a COP program for dyads of youth (9–10 years old) and their primary adult food preparer. Behavior change and perceptions were assessed through surveys and open-ended interviews. Across eight HSTA organizations, 43 teen leaders participated in teaching the iCook 4-H program to 24 dyads. Increased frequency of culinary skills, physical activity and mealtime behavior were reported by youth. Almost all adults (93%) reported that their youth had learned kitchen skills and that the program provided youth-adult quality time and developed culinary skills. Youth echoed adult perceptions with additional themes of food safety and physical activity. HSTA teen leaders perceived the program to be successful and reported the training they received to implement the program was adequate 98% of the time. HSTA teachers found the program to be beneficial for HSTA students in improving leadership, confidence and responsibility. iCook 4-H was feasible to be disseminated through teen leaders in the HSTA program. This teen-led approach could serve as a model for youth health-related programming

    Imaging and Spectroscopy of Galaxies Associated with Two z ~ 0.7 Damped Lyα Absorption Systems

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    We have identified galaxies near two quasars that are at the redshift of damped Lyα (DLA) systems in the UV spectra of the quasars. Both galaxies are actively forming stars. One galaxy has a luminosity close to the break in the local galaxy luminosity function, L*; the other is significantly fainter than L* and appears to be interacting with a nearby companion. Despite the strong selection effects favoring spectroscopic identification of the most luminous DLA galaxies, many of the spectroscopically identified DLA galaxies in the literature are sub-L*, suggesting that the majority of the DLA population is probably sub-L*, in contrast to Mg II absorbers at similar redshifts, whose mean luminosity is close to L*

    An Impact Mapping Method to Generate Robust Qualitative Evaluation of Community-Based Research Programs for Youth and Adults

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    Ripple Effect Mapping (REM) is an evaluation approach that has traditionally been used in community settings to visually map the impact of programming and community interventions. This manuscript utilizes the Community Capitals Framework (CCF) to inform REM and to better highlight the changes and impact between various levels of a community, following a childhood obesity prevention intervention. The addition of in-depth qualitative analyses makes this approach particularly useful for the evaluation of interventions with a research–community partnership focus. The objective of this study was to describe a CCF-informed REM approach with detailed protocol, training, and application to the community-based, childhood obesity prevention intervention, iCook 4-H, which targeted youth and adult pairs. This protocol includes the steps required to prepare for REM sessions of, ideally, six youth and adult pairs, one facilitator, and one or two evaluators/note takers. REM sessions typically begin with an icebreaker and appreciative inquiry activities that inform the REM mapping process that follows. In-depth qualitative analysis of the notes and map images captured during REM sessions ensure the rigor required for research-related interventions. Researchers, community members, and participants can use CCF-informed REM collectively as a robust evaluation tool to demonstrate, through visual mapping, the positive effects of community-partnered research programs

    Cooking Frequency Associated With Dietary Quality in iCook-4H Youth Participants at Baseline

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    Background: Increased intakes of ready-made and fast foods paralleled with decreased homemade food consumption have been associated with increased rates of obesity. Researchers have shown associations between cooking self-efficacy (SE) and cooking frequency (CF) with dietary quality and weight status. Some cooking interventions have shown positive associations with dietary outcomes, such as increased fruit and vegetable intake and decreased fast food consumption. There is still much unknown about SE and CF, especially among youth. Objective: Determine baseline SE and CF and the associations with dietary quality and body mass index (BMI) of youth enrolled in iCook 4H. Methods: Youth (n = 228, ages 9-10 years) completed online surveys assessing SE, CF, dietary quality, and demographics. Anthropometrics were collected to calculate BMI-for-age percentiles and weight categories. Descriptive statistics were completed for CF, SE, BMI categories, and demographics. Differences in CF and SE by sex, race, and participation in government assistance programs were determined through independent-sample t tests. Pearson correlations were used to assess the association between dietary quality and CF and SE. Associations between CF and dietary quality were assessed further through 2-way analyses of variance (ANOVAs) that included CF and sex and CF and race as independent variables. Associations between SE and CF and BMI were assessed through ANOVAs. Results : Thirty-seven percent of youth were overweight or obese. Females reported significantly higher CF than males (P = .042). Cooking frequency was positively associated with dietary quality (P \u3c .001), but BMI was not associated with dietary quality. SE was not associated with dietary quality or BMI. Conclusion: Based on results, CF was positively associated with dietary quality among youth. More research is needed to assess how different types of cooking relate to diet and BMI. Interventions are needed to determine whether increasing CF leads to better diet outcomes
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