635 research outputs found
Suicide ideation of individuals in online social networks
Suicide explains the largest number of death tolls among Japanese adolescents
in their twenties and thirties. Suicide is also a major cause of death for
adolescents in many other countries. Although social isolation has been
implicated to influence the tendency to suicidal behavior, the impact of social
isolation on suicide in the context of explicit social networks of individuals
is scarcely explored. To address this question, we examined a large data set
obtained from a social networking service dominant in Japan. The social network
is composed of a set of friendship ties between pairs of users created by
mutual endorsement. We carried out the logistic regression to identify users'
characteristics, both related and unrelated to social networks, which
contribute to suicide ideation. We defined suicide ideation of a user as the
membership to at least one active user-defined community related to suicide. We
found that the number of communities to which a user belongs to, the
intransitivity (i.e., paucity of triangles including the user), and the
fraction of suicidal neighbors in the social network, contributed the most to
suicide ideation in this order. Other characteristics including the age and
gender contributed little to suicide ideation. We also found qualitatively the
same results for depressive symptoms.Comment: 4 figures, 9 table
Analysis of a Large Sample of Neutrino-Induced Muons with the ArgoNeuT Detector
ArgoNeuT, or Argon Neutrino Test, is a 170 liter liquid argon time projection
chamber designed to collect neutrino interactions from the NuMI beam at Fermi
National Accelerator Laboratory. ArgoNeuT operated in the NuMI low-energy beam
line directly upstream of the MINOS Near Detector from September 2009 to
February 2010, during which thousands of neutrino and antineutrino events were
collected. The MINOS Near Detector was used to measure muons downstream of
ArgoNeuT. Though ArgoNeuT is primarily an R&D project, the data collected
provide a unique opportunity to measure neutrino cross sections in the 0.1-10
GeV energy range. Fully reconstructing the muon from these interactions is
imperative for these measurements. This paper focuses on the complete kinematic
reconstruction of neutrino-induced through-going muons tracks. Analysis of this
high statistics sample of minimum ionizing tracks demonstrates the reliability
of the geometric and calorimetric reconstruction in the ArgoNeuT detector
A first measurement of the interaction cross section of the tau neutrino
The DONuT experiment collected data in 1997 and published first results in
2000 based on four observed charged-current (CC) interactions. The
final analysis of the data collected in the experiment is presented in this
paper, based on protons on target using the 800 GeV
Tevatron beam at Fermilab. The number of observed CC interactions is
9, from a total of 578 observed neutrino interactions. We calculated the
energy-independent part of the tau-neutrino CC cross section (), relative to the well-known and cross sections. The
ratio / was found to be
. The CC cross section was found to be cm. Both results are in
agreement the Standard Model.Comment: 37 pages, 15 figure
Development of the Rural Active Living Perceived Environmental Support Scale (RALPESS)
Background: Evidence supports the role of physical and social environments in active living, including perception of environment. However, measurement of perceived environments in rural settings is lacking. This study describes the development of the Rural Active Living Perceived Environmental Support Scale (RALPESS). Methods: Premised on social ecological and cognitive perspectives, 85 initial items were generated through a literature review and a mixed-methods investigation of activity-friendly environments. Items were organized by resource areas town center, indoor and outdoor physical activity areas, schools, churches, and areas around the home/neighborhood-and submitted for expert panel review. In 2009, a revised questionnaire was disseminated to adolescents, parents, public school staff, and older adults in 2 rural southeastern United States counties. Principal component analysis with varimax rotation was used to explore factor structure (n = 542). Results: The final analysis yielded 33 items with 7 factors: 1) church facilities, 2) town center connectivity, 3) indoor areas, 4) around the home/neighborhood, 5) town center physical activity resources, 6) school grounds, and 7) outdoor areas. Conclusions: The RALPESS is a valid, internally consistent, and practically useful instrument to measure perceptions of rural environments in the context of physical activity across the lifespan. Confirmatory factor analysis is recommended to validate factor structure
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