1,328 research outputs found
Emergent regularities and scaling in armed conflict data
Armed conflict exhibits regularities beyond known power law distributions of
fatalities and duration over varying culture and geography. We systematically
cluster conflict reports from a database of events from Africa spanning
20 years into conflict avalanches. Conflict profiles collapse over a range of
scales. Duration, diameter, extent, fatalities, and report totals satisfy
mutually consistent scaling relations captured with a model combining
geographic spread and local conflict-site growth. The emergence of such social
scaling laws hints at principles guiding conflict evolution
Assessing weak hydrogen binding on Ca+ centers: An accurate many-body study with large basis sets
Weak H2 physisorption energies present a significant challenge to even the
best correlated theoretical many-body methods. We use the phaseless
auxiliary-field quantum Monte Carlo (AFQMC) method to accurately predict the
binding energy of Ca+ - 4H2. Attention has recently focused on this model
chemistry to test the reliability of electronic structure methods for H2
binding on dispersed alkaline earth metal centers. A modified Cholesky
decomposition is implemented to realize the Hubbard-Stratonovich transformation
efficiently with large Gaussian basis sets. We employ the largest
correlation-consistent Gaussian type basis sets available, up to cc-pCV5Z for
Ca, to accurately extrapolate to the complete basis limit. The calculated
potential energy curve exhibits binding with a double-well structure.Comment: 10 pages, 7 figures. Submitted to JC
Measurements of Charged Current Reactions of on
Charged Current reactions of on have been studied using a
decay-at-rest beam at the Los Alamos Neutron Science Center.
The cross section for the exclusive reaction
was measured to be cm. The observed
energy dependence of the cross section and angular distribution of the outgoing
electron agree well with theoretical expectations. Measurements are also
presented for inclusive transitions to excited states,
and compared with theoretical expectations. The
measured cross section, cm, is somewhat
lower than previous measurements and than a continuum random phase
approximation calculation. It is in better agreement with a recent shell model
calculation.Comment: 34 pages, 18 figures, accepted to PRC, replaced with the accepted on
Evidence of strategic periodicities in collective conflict dynamics
We analyze the timescales of conflict decision-making in a primate society.
We present evidence for multiple, periodic timescales associated with social
decision-making and behavioral patterns. We demonstrate the existence of
periodicities that are not directly coupled to environmental cycles or known
ultraridian mechanisms. Among specific biological and socially-defined
demographic classes, periodicities span timescales between hours and days, and
many are not driven by exogenous or internal regularities. Our results indicate
that they are instead driven by strategic responses to social interaction
patterns. Analyses also reveal that a class of individuals, playing a critical
functional role, policing, have a signature timescale on the order of one hour.
We propose a classification of behavioral timescales analogous to those of the
nervous system, with high-frequency, or -scale, behavior occurring on
hour-long scales, through to multi-hour, or -scale, behavior, and,
finally periodicities observed on a timescale of days.Comment: 22 pages, 7 figures, 1 table. Accepted for publication in Journal of
the Royal Society Interfac
Effects of neutrino oscillations and neutrino magnetic moments on elastic neutrino-electron scattering
We consider elastic antineutrino-electron scattering taking into account
possible effects of neutrino masses and mixing and of neutrino magnetic moments
and electric dipole moments. Having in mind antineutrinos produced in a nuclear
reactor we compute, in particular, the weak-electromagnetic interference terms
which are linear in the magnetic (electric dipole) moments and also in the
neutrino masses. We show that these terms are, however, suppressed compared to
the pure weak and electromagnetic cross section. We also comment upon the
possibility of using the electromagnetic cross section to investigate neutrino
oscillations.Comment: 12 pages, REVTEX file, no figures, submitted to Phys.Rev.
Neutrino-nucleus reactions on ^{12}C and ^{16}O
Exclusive and inclusive cross-sections and
-capture rates are calculated for ^{12}C and ^{16}O using the consistent
random phase approximation (RPA) and pairing model. After a pairing correction
is introduced to the RPA results the flux-averaged theoretical cross-sections and -capture rates in C are
in good agreement with experiment. In particular when one takes into account
the experimental error bars, the recently measured range of values for the
cross-section is in agreement with the present theoretical
results. Predictions of and cross-sections in
^{16}O are also presented.Comment: 13 pages, Revte
A new method for tracking of motor skill learning through practical application of Fittsâ law
This article is made available through the Brunel Open Access Publishing Fund.A novel upper limb motor skill measure, task productivity rate (TPR) was developed integrating speed and spatial error, delivered by a practical motor skill rehabilitation task (MSRT). This prototype task involved placement of 5 short pegs horizontally on a spatially configured rail array. The stability of TPR was tested on 18 healthy right-handed adults (10 women, 8 men, median age 29 years) in a prospective single-session quantitative within-subjects study design. Manipulations of movement rate 10% faster and slower relative to normative states did not significantly affect TPR, F(1.387, 25.009) = 2.465, p = .121. A significant linear association between completion time and error was highest during the normative state condition (Pearson's r = .455, p < .05). Findings provided evidence that improvements in TPR over time reflected motor learning with possible changes in coregulation behavior underlying practice under different conditions. These findings extend Fittsâ law theory to tracking of practical motor skill using a dexterity task, which could have potential clinical applications in rehabilitation
Asymmetric interlimb transfer of concurrent adaptation to opposing dynamic forces
Interlimb transfer of a novel dynamic force has been well documented. It has also been shown that unimanual adaptation to opposing novel environments is possible if they are associated with different workspaces. The main aim of this study was to test if adaptation to opposing velocity dependent viscous forces with one arm could improve the initial performance of the other arm. The study also examined whether this interlimb transfer occurred across an extrinsic, spatial, coordinative system or an intrinsic, joint based, coordinative system. Subjects initially adapted to opposing viscous forces separated by target location. Our measure of performance was the correlation between the speed profiles of each movement within a force condition and an âaverageâ trajectory within null force conditions. Adaptation to the opposing forces was seen during initial acquisition with a significantly improved coefficient in epoch eight compared to epoch one. We then tested interlimb transfer from the dominant to non-dominant arm (D â ND) and vice-versa (ND â D) across either an extrinsic or intrinsic coordinative system. Interlimb transfer was only seen from the dominant to the non-dominant limb across an intrinsic coordinative system. These results support previous studies involving adaptation to a single dynamic force but also indicate that interlimb transfer of multiple opposing states is possible. This suggests that the information available at the level of representation allowing interlimb transfer can be more intricate than a general movement goal or a single perceived directional error
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