613 research outputs found
Rethinking how and when to report descriptions of behavior change content within interventions: a case study of an ongoing physical activity trial (ready steady 3.0)
Specifications of what and how much health behavior change (BC) content within research interventions are needed to advance BC science, its implementation, and dissemination. We analyzed the types and dosages of the smallest potentially active BC ingredients and associated behavioral prescriptions intended to be delivered in an ongoing physical activity optimization trial for older adults (Ready Steady 3.0 [RS3]). We defined BC types as behavior change techniques (BCT) and behavioral prescriptions. Our protocol integrated the BCT Taxonomy coding procedures with BCT roles (primary or secondary) and, when relevant, linkages to behavioral prescriptions. Primary BCTs targeted theoretical mechanisms of action, whereas secondary BCTs supported primary BCT delivery. Behavioral prescriptions represented what participants were encouraged to do with each primary BCT in RS3 (ascertain, practice, implement). We assessed dosage parameters of duration, frequency, and amount in each BCT and prescription.
Results provided a catalog of in-depth, multidimensional content specifications with 12 primary BCTs, each supported by 2-7 secondary BCTs, with dosages ranging from 2 to 8 weeks, 1 to 8 contacts, and 5 to 451 minutes. Minutes spent on behavioral prescriptions varied: ascertain (1 to 41), practice (5 to 315), and implement (0 to 38). Results can be organized and summarized in varied ways (e.g., by content component) to strengthen future assessments of RS3 fidelity and intervention refinement.
Results highlight potential benefits of this early, integrated approach to analyzing BC content and frames questions about how such information might be incorporated and disseminated with reporting research outcomes
Comparing benefits from many possible computed tomography lung cancer screening programs: Extrapolating from the National Lung Screening Trial using comparative modeling
Background: The National Lung Screening Trial (NLST) demonstrated that in current and former smokers aged 55 to 74 years, with at least 30 pack-years of cigarette smoking history and who had quit smoking no more than 15 years ago, 3 annual computed tomography (CT) screens reduced lung cancer-specific mortality by 20% relative to 3 annual chest X-ray screens. We compared the benefits achievable with 576 lung cancer screening programs that varied CT screen number and frequency, ages of screening, and eligibility based on smoking. Methods and Findings: We used five independent microsimulation models with lung cancer natural history parameters previously calibrated to the NLST to simulate life histories of the US cohort born in 1950 under all 576 programs. 'Efficient' (within model) programs prevented the greatest number of lung cancer deaths, compared to no screening, for a given number of CT screens. Among 120 'consensus efficient' (identified as efficient across models) programs, the average starting age was 55 years, the stopping age was 80 or 85 years, the average minimum pack-years was 27, and the maximum years since quitting was 20. Among consensus efficient programs, 11% to 40% of the cohort was screened, and 153 to 846 lung cancer deaths were averted per 100,000 people. In all models, annual screening based on age and smoking eligibility in NLST was not efficient; continuing screening to age 80 or 85 years was more efficient. Conclusions: Consensus results from five models identified a set of efficient screening programs that include annual CT lung cancer screening using criteria like NLST eligibility but extended to older ages. Guidelines for screening should also consider harms of screening and individual patient characteristics
Hadron Production in Diffractive Deep-Inelastic Scattering
Characteristics of hadron production in diffractive deep-inelastic
positron-proton scattering are studied using data collected in 1994 by the H1
experiment at HERA. The following distributions are measured in the
centre-of-mass frame of the photon dissociation system: the hadronic energy
flow, the Feynman-x (x_F) variable for charged particles, the squared
transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a
function of x_F. These distributions are compared with results in the gamma^* p
centre-of-mass frame from inclusive deep-inelastic scattering in the
fixed-target experiment EMC, and also with the predictions of several Monte
Carlo calculations. The data are consistent with a picture in which the
partonic structure of the diffractive exchange is dominated at low Q^2 by hard
gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.
Measurement of Leading Proton and Neutron Production in Deep Inelastic Scattering at HERA
Deep--inelastic scattering events with a leading baryon have been detected by
the H1 experiment at HERA using a forward proton spectrometer and a forward
neutron calorimeter. Semi--inclusive cross sections have been measured in the
kinematic region 2 <= Q^2 <= 50 GeV^2, 6.10^-5 <= x <= 6.10^-3 and baryon p_T
<= MeV, for events with a final state proton with energy 580 <= E' <= 740 GeV,
or a neutron with energy E' >= 160 GeV. The measurements are used to test
production models and factorization hypotheses. A Regge model of leading baryon
production which consists of pion, pomeron and secondary reggeon exchanges
gives an acceptable description of both semi-inclusive cross sections in the
region 0.7 <= E'/E_p <= 0.9, where E_p is the proton beam energy. The leading
neutron data are used to estimate for the first time the structure function of
the pion at small Bjorken--x.Comment: 30 pages, 9 figures, 2 tables, submitted to Eur. Phys.
Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV
We report the results of a study of color coherence effects in ppbar
collisions based on data collected by the D0 detector during the 1994-1995 run
of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8
TeV. Initial-to-final state color interference effects are studied by examining
particle distribution patterns in events with a W boson and at least one jet.
The data are compared to Monte Carlo simulations with different color coherence
implementations and to an analytic modified-leading-logarithm perturbative
calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters
Low Q^2 Jet Production at HERA and Virtual Photon Structure
The transition between photoproduction and deep-inelastic scattering is
investigated in jet production at the HERA ep collider, using data collected by
the H1 experiment. Measurements of the differential inclusive jet
cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the
transverse energy and the pseudorapidity of the jets in the virtual
photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3
< y < 0.6. The interpretation of the results in terms of the structure of the
virtual photon is discussed. The data are best described by QCD calculations
which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure
Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA
An investigation of the hadronic final state in diffractive and
non--diffractive deep--inelastic electron--proton scattering at HERA is
presented, where diffractive data are selected experimentally by demanding a
large gap in pseudo --rapidity around the proton remnant direction. The
transverse energy flow in the hadronic final state is evaluated using a set of
estimators which quantify topological properties. Using available Monte Carlo
QCD calculations, it is demonstrated that the final state in diffractive DIS
exhibits the features expected if the interaction is interpreted as the
scattering of an electron off a current quark with associated effects of
perturbative QCD. A model in which deep--inelastic diffraction is taken to be
the exchange of a pomeron with partonic structure is found to reproduce the
measurements well. Models for deep--inelastic scattering, in which a
sizeable diffractive contribution is present because of non--perturbative
effects in the production of the hadronic final state, reproduce the general
tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil
A Search for Selectrons and Squarks at HERA
Data from electron-proton collisions at a center-of-mass energy of 300 GeV
are used for a search for selectrons and squarks within the framework of the
minimal supersymmetric model. The decays of selectrons and squarks into the
lightest supersymmetric particle lead to final states with an electron and
hadrons accompanied by large missing energy and transverse momentum. No signal
is found and new bounds on the existence of these particles are derived. At 95%
confidence level the excluded region extends to 65 GeV for selectron and squark
masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure
Measurement of D* Meson Cross Sections at HERA and Determination of the Gluon Density in the Proton using NLO QCD
With the H1 detector at the ep collider HERA, D* meson production cross
sections have been measured in deep inelastic scattering with four-momentum
transfers Q^2>2 GeV2 and in photoproduction at energies around W(gamma p)~ 88
GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe
the differential cross sections within theoretical and experimental
uncertainties. Using these calculations, the NLO gluon momentum distribution in
the proton, x_g g(x_g), has been extracted in the momentum fraction range
7.5x10^{-4}< x_g <4x10^{-2} at average scales mu^2 =25 to 50 GeV2. The gluon
momentum fraction x_g has been obtained from the measured kinematics of the
scattered electron and the D* meson in the final state. The results compare
well with the gluon distribution obtained from the analysis of scaling
violations of the proton structure function F_2.Comment: 27 pages, 9 figures, 2 tables, submitted to Nucl. Phys.
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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