1,685 research outputs found
Modelling the nucleon wave function from soft and hard processes
Current light-cone wave functions for the nucleon are unsatisfactory since
they are in conflict with the data of the nucleon's Dirac form factor at large
momentum transfer. Therefore, we attempt a determination of a new wave function
respecting theoretical ideas on its parameterization and satisfying the
following constraints: It should provide a soft Feynman contribution to the
proton's form factor in agreement with data; it should be consistent with
current parameterizations of the valence quark distribution functions and
lastly it should provide an acceptable value for the \jp \to N \bar N decay
width. The latter process is calculated within the modified perturbative
approach to hard exclusive reactions. A simultaneous fit to the three sets of
data leads to a wave function whose -dependent part, the distribution
amplitude, shows the same type of asymmetry as those distribution amplitudes
constrained by QCD sum rules. The asymmetry is however much more moderate as in
those amplitudes. Our distribution amplitude resembles the asymptotic one in
shape but the position of the maximum is somewhat shifted.Comment: 32 pages RevTex + PS-file with 5 figures in uu-encoded, compressed
fil
Development and evaluation of a youth mental health community awareness campaign – The Compass Strategy
BACKGROUND: Early detection and treatment of mental disorders in adolescents and young adults can lead to better health outcomes. Mental health literacy is a key to early recognition and help seeking. Whilst a number of population health initiatives have attempted to improve mental health literacy, none to date have specifically targeted young people nor have they applied the rigorous standards of population health models now accepted as best practice in other health areas. This paper describes the outcomes from the application of a health promotion model to the development, implementation and evaluation of a community awareness campaign designed to improve mental health literacy and early help seeking amongst young people. METHOD: The Compass Strategy was implemented in the western metropolitan Melbourne and Barwon regions of Victoria, Australia. The Precede-Proceed Model guided the population assessment, campaign strategy development and evaluation. The campaign included the use of multimedia, a website, and an information telephone service. Multiple levels of evaluation were conducted. This included a cross-sectional telephone survey of mental health literacy undertaken before and after 14 months of the campaign using a quasi-experimental design. Randomly selected independent samples of 600 young people aged 12–25 years from the experimental region and another 600 from a comparison region were interviewed at each time point. A series of binary logistic regression analyses were used to measure the association between a range of campaign outcome variables and the predictor variables of region and time. RESULTS: The program was judged to have an impact on the following variables, as indicated by significant region-by-time interaction effects (p < 0.05): awareness of mental health campaigns, self-identified depression, help for depression sought in the previous year, correct estimate of prevalence of mental health problems, increased awareness of suicide risk, and a reduction in perceived barriers to help seeking. These effects may be underestimated because media distribution error resulted in a small amount of print material "leaking" into the comparison region. CONCLUSION: We believe this is the first study to apply the rigorous standards of a health promotion model including the use of a control region to a mental health population intervention. The program achieved many of its aims despite the relatively short duration and moderate intensity of the campaign
An experimental study exploring the impact of vignette gender on the quality of university students’ mental health first aid for peers with symptoms of depression
Background
University students have high rates of depression, and friends are often the most commonly-used source of support for emotional distress in this population. This study aimed to explore students’ ability to provide effective support for their peers with depressive symptoms and the factors influencing the quality of their mental health first aid (MHFA) skills, including students’ gender, course of study, and gender of student experiencing depression.
Methods
Via an online survey, students at two British universities (N = 483) were quasi-randomly allocated to view a video vignette of either a male or female student depicting symptoms of depression. An open-ended question probed MHFA actions they would take to help the vignette character, which were rated using a standardised scoring scheme based on MHFA guidelines.
Results
Students reported low MHFA scores (mean 2.89, out of possible 12). The most commonly reported action was provision of support and information, but only eight (1.6 %) students stated an intention to assess risk of harm. Those studying clinically non-relevant degrees with limited mental health content reported poorer MHFA (p = <0.001) and were less confident about their ability to support a friend with depression (p = 0.04). There was no main effect of vignette gender, but within the group of students on non-relevant courses the male vignette received significantly poorer MHFA than the female vignette (p = 0.02). A significant three-way interaction found that male participants studying non-relevant degrees who viewed a male vignette had poorer MHFA compared to females studying non-relevant degrees who viewed the female vignette (p = 0.005).
Conclusions
Most students lack the necessary MHFA skills to support friends suffering from symptoms of depression, or to help them get appropriate support and prevent risk of harm. Students on courses which do not include mental health related content are particularly ill-equipped to support male students, with male students receiving the poorest quality MHFA from fellow male students on these courses. MHFA training has the potential to improve outcomes for students with depression, and could have a valuable role in reducing the excess risk of harm seen in male students
Search for a Technicolor omega_T Particle in Events with a Photon and a b-quark Jet at CDF
If the Technicolor omega_T particle exists, a likely decay mode is omega_T ->
gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We
have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab
Tevatron for events with a photon and two jets, where one of the jets must
contain a secondary vertex implying the presence of a b quark. We find no
excess of events above standard model expectations. We express the result of an
exclusion region in the M_omega_T - M_pi_T mass plane.Comment: 14 pages, 2 figures. Available from the CDF server (PS with figs):
http://www-cdf.fnal.gov/physics/pub98/cdf4674_omega_t_prl_4.ps
FERMILAB-PUB-98/321-
Measurement of the B0 anti-B0 oscillation frequency using l- D*+ pairs and lepton flavor tags
The oscillation frequency Delta-md of B0 anti-B0 mixing is measured using the
partially reconstructed semileptonic decay anti-B0 -> l- nubar D*+ X. The data
sample was collected with the CDF detector at the Fermilab Tevatron collider
during 1992 - 1995 by triggering on the existence of two lepton candidates in
an event, and corresponds to about 110 pb-1 of pbar p collisions at sqrt(s) =
1.8 TeV. We estimate the proper decay time of the anti-B0 meson from the
measured decay length and reconstructed momentum of the l- D*+ system. The
charge of the lepton in the final state identifies the flavor of the anti-B0
meson at its decay. The second lepton in the event is used to infer the flavor
of the anti-B0 meson at production. We measure the oscillation frequency to be
Delta-md = 0.516 +/- 0.099 +0.029 -0.035 ps-1, where the first uncertainty is
statistical and the second is systematic.Comment: 30 pages, 7 figures. Submitted to Physical Review
Search for New Particles Decaying to top-antitop in proton-antiproton collisions at squareroot(s)=1.8 TeV
We use 106 \ipb of data collected with the Collider Detector at Fermilab to
search for narrow-width, vector particles decaying to a top and an anti-top
quark. Model independent upper limits on the cross section for narrow, vector
resonances decaying to \ttbar are presented. At the 95% confidence level, we
exclude the existence of a leptophobic \zpr boson in a model of
topcolor-assisted technicolor with mass M_{\zpr} 480 \gev for natural
width = 0.012 M_{\zpr}, and M_{\zpr} 780 \gev for =
0.04 M_{\zpr}.Comment: The CDF Collaboration, submitted to PRL 25-Feb-200
Double Diffraction Dissociation at the Fermilab Tevatron Collider
We present results from a measurement of double diffraction dissociation in
collisions at the Fermilab Tevatron collider. The production cross
section for events with a central pseudorapidity gap of width
(overlapping ) is found to be [] at [630]
GeV. Our results are compared with previous measurements and with predictions
based on Regge theory and factorization.Comment: 10 pages, 4 figures, using RevTeX. Submitted to Physical Review
Letter
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