562 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
Wide-angle elastic scattering and color randomization
Baryon-baryon elastic scattering is considered in the independent scattering
(Landshoff) mechanism. It is suggested that for scattering at moderate
energies, direct and interchange quark channels contribute with equal color
coefficients because the quark color is randomized by soft gluon exchange
during the hadronization stage. With this assumption, it is shown that the
ratio of cross sections at CM angle
decreases from a high energy value of R_{\pbar p / pp} \approx 1/2.7, down to
R_{\pbar p / pp} \approx 1/28, compatible with experimental data at moderate
energies. This sizable fall in the ratio seems to be characteristic of the
Landshoff mechanism, in which changes at the quark level have a strong effect
precisely because the hadronic process occurs via multiple quark scatterings.
The effect of color randomization on the angular distribution of proton-proton
elastic scattering and the cross section ratio is also discussed.Comment: 18 pages, latex2e, 4 uuencoded figures, include
Advanced Trip Generation/Attraction Models
In this paper, advanced trip generation/attraction models are proposed. A multiple linear regression (MLR) model has been created from zonal data. These models are compared to each other by analyzing their hypothesis and the required adjustments. Additionally, advanced generation/attraction models considering spatial correlation are proposed, and their improvements with reference to previous models not considering spatial correlation are analyzed.
A global spatial correlation model that conducts a joint review of every unit in the sample to determine whether the spatial units are randomly distributed or in accordance with a certain pattern is specified. To consider cluster situations in a given area, a local spatial correlation model aimed to measure the spatial autocorrelation to place each observation is defined.
The models are applied to the Santander metropolitan area (in Spain) in order to obtain advanced generation/attraction models in that city. For Santander, the models considering spatial dependence among observations have better results than the MLR models.This work was made possible thanks to a grant from the Spanish Ministerio de EconomĂa y Competitividad with
additional financing from FEDER funds to the project TRA2012-3765
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
The ArgoNeuT Detector in the NuMI Low-Energy beam line at Fermilab
The ArgoNeuT liquid argon time projection chamber has collected thousands of
neutrino and antineutrino events during an extended run period in the NuMI
beam-line at Fermilab. This paper focuses on the main aspects of the detector
layout and related technical features, including the cryogenic equipment, time
projection chamber, read-out electronics, and off-line data treatment. The
detector commissioning phase, physics run, and first neutrino event displays
are also reported. The characterization of the main working parameters of the
detector during data-taking, the ionization electron drift velocity and
lifetime in liquid argon, as obtained from through-going muon data complete the
present report.Comment: 43 pages, 27 figures, 5 tables - update referenc
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