154 research outputs found
A sequence analysis of behaviors in immersive virtual reality for indoor earthquake and post-earthquake evacuation
Behavioral sequence analysis (BSA) gives insights to understand and model individual behaviors. The present study uses BSA for a virtual earthquake. The virtual earthquake drill was facilitated by a head-mounted display (HMD)-based immersive virtual reality (IVR) system. Eighty-three participants experienced a full earthquake and post-earthquake evacuation in a virtual hospital building. Concurrent verbal protocol analysis (VPA) and retrospective video analysis of the footage of participants’ in-IVR behaviors have been conducted to identify the behavioral sequence of participants. As a result, behavioral transition diagrams are generated, showing the progression of behaviors exhibited in the virtual earthquake drill. A variety of behavioral paths for each individual participant is presented using a visual analytics approach. The behavioral transition diagrams and behavioral paths expose the full picture of human behaviors in an earthquake emergency, which are vital to developing behavior-oriented strategies for earthquake emergencies.Publishe
Neutron-Neutron Fusion
The neutron-neutron fusion process, , at very low neutron
energies is studied in the framework of pionless effective field theory that
incorporates dibaryon fields. The cross section and electron energy spectrum
for this process are calculated up to next-to-leading order. We include the
radiative corrections of calculated for the one-body
transition amplitude. The precision of our theoretical estimates is found to be
governed essentially by the accuracy with which the empirical values of the
neutron-neutron scattering length and effective range are currently known. Also
discussed is the precision of theoretical estimates of the transition rates of
related electroweak processes in few-nucleon systems.Comment: 14 pages, 4 figures, minor correction, accepted for publication in
Phys. Lett.
Translation, validity, and reliability of the European Portuguese version of the Touch Experiences and Attitudes Questionnaire
Background. Positive touch experiences have proved to be extremely important throughout our lifespan, with cascading effects on our social life. However, few questionnaires are available to measure attitudes and experiences of touch in the Portuguese population. This study aimed to translate and validate the European Portuguese version of the Touch Experiences and Attitudes Questionnaire (TEAQ), as a reliable and valid instrument to measure different aspects of affective touch experiences and attitudes. Methods. Therefore, an online sample of 384 (299 females and 85 males) participants, aged between 18 and 75 years (M = 24.59; SD = 9.56) was collected. Multidimensional Rasch model and confirmatory factor analysis were carried out, and also reliability and convergent and discriminant validity were determined. In addition, we examined sex differences in attitudes and experiences of touch. Results. Results showed good fit indexes for the 52-item six-factor model structure (friends and family touch, current intimate touch, childhood touch, attitudes to self-care, attitudes to intimate touch, and attitudes to unfamiliar touch). This instrument also showed good reliability and acceptable convergent and discriminant validity. Significant sex differences were found, with female participants reporting more positive touch experiences (including childhood touch, friends and family touch, and current intimate touch) and a more favourable attitude to self-care, with males showing a more positive attitude towards unfamiliar touch. Regarding attitudes towards the intimate touch, scores for both groups were comparable. Conclusion. Overall, the European Portuguese version of the TEAQ presented good psychometric properties and appears to be a reliable and valid self-report measure, being a useful and beneficial instrument in research and clinical settings
The two-nucleon system at next-to-next-to-next-to-leading order
We consider the two-nucleon system at next-to-next-to-next-to-leading order
(N^3LO) in chiral effective field theory. The two-nucleon potential at N^3LO
consists of one-, two- and three-pion exchanges and a set of contact
interactions with zero, two and four derivatives. In addition, one has to take
into account various isospin-breaking and relativistic corrections. We employ
spectral function regularization for the multi-pion exchanges. Within this
framework, it is shown that the three-pion exchange contribution is negligibly
small. The low-energy constants (LECs) related to pion-nucleon vertices are
taken consistently from studies of pion-nucleon scattering in chiral
perturbation theory. The total of 26 four-nucleon LECs has been determined by a
combined fit to some np and pp phase shifts from the Nijmegen analysis together
with the nn scattering length. The description of nucleon-nucleon scattering
and the deuteron observables at N^3LO is improved compared to the one at NLO
and NNLO. The theoretical uncertainties in observables are estimated based on
the variation of the cut-offs in the spectral function representation of the
potential and in the regulator utilized in the Lippmann-Schwinger equation.Comment: 62 pp, 13 fig
Effects of the magnetic moment interaction between nucleons on observables in the 3N continuum
The influence of the magnetic moment interaction of nucleons on
nucleon-deuteron elastic scattering and breakup cross sections and on elastic
scattering polarization observables has been studied. Among the numerous
elastic scattering observables only the vector analyzing powers were found to
show a significant effect, and of opposite sign for the proton-deuteron and
neutron-deuteron systems. This finding results in an even larger discrepancy
than the one previously established between neutron-deuteron data and
theoretical calculations. For the breakup reaction the largest effect was found
for the final-state-interaction cross sections. The consequences of this
observation on previous determinations of the ^1S_0 scattering lengths from
breakup data are discussed.Comment: 24 pages, 6 ps figures, 1 png figur
Light-year Scale Radio Cores in Four LINER Galaxies
The LINER galaxies NGC 2911, NGC 3079, NGC 3998, and NGC 6500 were observed
at 5 GHz with the European VLBI Network at a resolution of 5 milliarcsecond and
found to possess flat-spectrum, variable, high-brightness temperature ( K) radio cores. These radio characteristics reinforce the view that
these LINERs host central engines associated with active galactic nuclei.Comment: 6 page
A New Measurement of the 1S0 Neutron-Neutron Scattering Length using the Neutron-Proton Scattering Length as a Standard
The present paper reports high-accuracy cross-section data for the 2H(n,nnp)
reaction in the neutron-proton (np) and neutron-neutron (nn)
final-state-interaction (FSI) regions at an incident mean neutron energy of
13.0 MeV. These data were analyzed with rigorous three-nucleon calculations to
determine the 1S0 np and nn scattering lengths, a_np and a_nn. Our results are
a_nn = -18.7 +/- 0.6 fm and a_np = -23.5 +/- 0.8 fm. Since our value for a_np
obtained from neutron-deuteron (nd) breakup agrees with that from free np
scattering, we conclude that our investigation of the nn FSI done
simultaneously and under identical conditions gives the correct value for a_nn.
Our value for a_nn is in agreement with that obtained in pion-deuteron capture
measurements but disagrees with values obtained from earlier nd breakup
studies.Comment: 4 pages and 3 figure
The three-nucleon bound state using realistic potential models
The bound states of H and He have been calculated using the Argonne
plus the Urbana three-nucleon potential. The isospin state
have been included in the calculations as well as the - mass difference.
The H-He mass difference has been evaluated through the charge
dependent terms explicitly included in the two-body potential. The calculations
have been performed using two different methods: the solution of the Faddeev
equations in momentum space and the expansion on the correlated hyperspherical
harmonic basis. The results are in agreement within 0.1% and can be used as
benchmark tests. Results for the CD-Bonn interaction are also presented. It is
shown that the H and He binding energy difference can be predicted
model independently.Comment: 5 pages REVTeX 4, 1 figures, 6 table
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