110 research outputs found

    Coherent Photoproduction of pi^+ from 3^He

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    We have measured the differential cross section for the Îł\gamma3^3He→π+t\rightarrow \pi^+ t reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid 3^3He target. The differential cross sections for the Îł\gamma3^3He→π+t\rightarrow \pi^+ t reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles, showing that additional components must be added to the model.Comment: 11 pages, 16 figure

    A Bayesian analysis of pentaquark signals from CLAS data

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    We examine the results of two measurements by the CLAS collaboration, one of which claimed evidence for a Θ+\Theta^{+} pentaquark, whilst the other found no such evidence. The unique feature of these two experiments was that they were performed with the same experimental setup. Using a Bayesian analysis we find that the results of the two experiments are in fact compatible with each other, but that the first measurement did not contain sufficient information to determine unambiguously the existence of a Θ+\Theta^{+}. Further, we suggest a means by which the existence of a new candidate particle can be tested in a rigorous manner.Comment: 5 pages, 3 figure

    Two family interventions to reduce BMI in low-income urban youth: A randomized trial

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    BACKGROUND: Our primary aim was to evaluate the effects of 2 family-based obesity management interventions compared with a control group on BMI in low-income adolescents with overweight or obesity. METHODS: In this randomized clinical trial, 360 urban-residing youth and a parent were randomly assigned to 1 of 2 behaviorally distinct family interventions or an education-only control group. Eligible children were entering the sixth grade with a BMI $85th percentile. Interventions were 3 years in length; data were collected annually for 3 years. Effects of the interventions on BMI slope (primary outcome) over 3 years and a set of secondary outcomes were assessed. RESULTS: Participants were primarily African American (77%), had a family income of,25 000 per year, and obese at enrollment (68%). BMI increased over time in all study groups, with group increases ranging from 0.95 to 1.08. In an intent-to-treat analysis, no significant differences were found in adjusted BMI slopes between either of the family-based interventions and the control group (P = .35). No differences were found between the experimental and control groups on secondary outcomes of diet, physical activity, sleep, perceived stress, or cardiometabolic factors. No evidence of effect modification of the study arms by sex, race and/or ethnicity, household income, baseline levels of child and parent obesity, or exposure to a school fitness program were found. CONCLUSIONS: In this low-income, adolescent population, neither of the family-based interventions improved BMI or health-related secondary outcomes. Future interventions should more fully address poverty and other social issues contributing to childhood obesity

    First measurement of direct f0(980)f_0(980) photoproduction on the proton

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    We report on the results of the first measurement of exclusive f0(980)f_0(980) meson photoproduction on protons for EÎł=3.0−3.8E_\gamma=3.0 - 3.8 GeV and −t=0.4−1.0-t = 0.4-1.0 GeV2^2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the π+π−\pi^+ \pi^- channel by performing a partial wave analysis of the reaction Îłp→pπ+π−\gamma p \to p \pi^+ \pi^-. Clear evidence of the f0(980)f_0(980) meson was found in the interference between PP and SS waves at Mπ+π−∌1M_{\pi^+ \pi^-}\sim 1 GeV. The SS-wave differential cross section integrated in the mass range of the f0(980)f_0(980) was found to be a factor of 50 smaller than the cross section for the ρ\rho meson. This is the first time the f0(980)f_0(980) meson has been measured in a photoproduction experiment

    Analysis of LIGO data for gravitational waves from binary neutron stars

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    We report on a search for gravitational waves from coalescing compact binary systems in the Milky Way and the Magellanic Clouds. The analysis uses data taken by two of the three LIGO interferometers during the first LIGO science run and illustrates a method of setting upper limits on inspiral event rates using interferometer data. The analysis pipeline is described with particular attention to data selection and coincidence between the two interferometers. We establish an observational upper limit of R<\mathcal{R}<1.7 \times 10^{2}peryearperMilkyWayEquivalentGalaxy(MWEG),with90coalescencerateofbinarysystemsinwhicheachcomponenthasamassintherange1−−3 per year per Milky Way Equivalent Galaxy (MWEG), with 90% confidence, on the coalescence rate of binary systems in which each component has a mass in the range 1--3 M_\odot$.Comment: 17 pages, 9 figure

    Poetry, painting and change on the edge of England

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    In this article we discuss our creative research on and with a contested coastal community on one of the UK's last existing plotlands, the humberston Fitties. Plotlands can be briefly defined as places where individuals have historically self‐built holiday houses. This 56‐acre strip of land with 319 chalets is on the Humber estuary and lies close to Cleethorpes, a seaside resort, and Grimsby, a seaport now facing post‐industrial decline. Our cross‐disciplinary collaborative practice between poetry and visual art explores open, environmentally aware engagements and methodologies with landscape and rural place. We investigate the relation of social, environmental and energy politics, looking out to land and sea and back to the community. Our results include original art and poetry presented innovatively together in exhibitions and books, in addition to local people's responses to our methodologies and the work itself

    How breakfast happens in the café

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    In this article I present an ethnographic study of `breakfast in the café', to begin to document the orderly properties of an emergent timespace. In so doing, the aim is to provide a description of the local production of timespace and a consideration of a change to the daily rhythm of city life. Harold Garfinkel and David Sudnow's study of a chemistry lecture is drawn upon as an exemplary study of the collective creation of an event. Attention is drawn to the centrality of sequentiality as part of the orderly properties of occasioned places. As part of examining the sequences I chart the ongoing emergence of features of breakfast time in the café such as `the first customer', `crowded' and `quiet'. In closing the article, I consider how changes in the rhythm of the city are made apprehensible to its residents

    Designing a broad-spectrum integrative approach for cancer prevention and treatment

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    Targeted therapies and the consequent adoption of "personalized" oncology have achieved notablesuccesses in some cancers; however, significant problems remain with this approach. Many targetedtherapies are highly toxic, costs are extremely high, and most patients experience relapse after a fewdisease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistantimmortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are notreliant upon the same mechanisms as those which have been targeted). To address these limitations, aninternational task force of 180 scientists was assembled to explore the concept of a low-toxicity "broad-spectrum" therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspectsof relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a widerange of high-priority targets (74 in total) that could be modified to improve patient outcomes. For thesetargets, corresponding low-toxicity therapeutic approaches were then suggested, many of which werephytochemicals. Proposed actions on each target and all of the approaches were further reviewed forknown effects on other hallmark areas and the tumor microenvironment. Potential contrary or procar-cinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixedevidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of therelationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. Thisnovel approach has potential to be relatively inexpensive, it should help us address stages and types ofcancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for futureresearch is offered

    Deeply Virtual Compton Scattering Beam-Spin Asymmetries

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    The beam spin asymmetries in the hard exclusive electroproduction of photons on the proton (ep -> epg) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (x_B from 0.11 to 0.58, Q^2 from 1 to 4.8 GeV^2, -t from 0.09 to 1.8 GeV^2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A = a*sin(phi)/[1+c*cos(phi)]. This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.Comment: 1 tex file (6 pages), 4 (eps) figure
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