2,019 research outputs found
Dirac Coupled-channel Analyses of Polarized Proton Scatterings to the 2 Gamma Vibrational Band in Mg and Mg
Dirac coupled channel calculations are performed phenomenologically for the
high-lying excited states that belong to the 2 gamma vibrational band at
the 800-MeV polarized proton inelastic scatterings from the s-d shell nuclei,
Mg and Mg. Optical potential model is used and scalar and
time-like vector potentials are considered as direct potentials. First-order
vibrational collective models are used to obtain the transition optical
potentials in order to accommodate the high-lying excited vibrational
collective states. The complicated Dirac coupled channel equations are solved
phenomenologically to reproduce the differential cross section and analyzing
power data by varying the optical potential and deformation parameters.
It is found that the relativistic Dirac coupled channel calculation could
describe the high-lying excited states of the 2 gamma vibrational band at
the 800-MeV polarized proton inelastic scatterings from s-d shell nuclei
Mg and Mg reasonably well, showing better agreement with the
experimental data compared to the results obtained from the nonrelativistic
calculations. Calculated deformation parameters for the excited states are
analyzed and compared with those of nonrelativistic calculations.Comment: 13pages, 6 figures. arXiv admin note: text overlap with
arXiv:1501.00650, arXiv:1407.5441, arXiv:1511.0172
Identification of Hessian matrix in distributed gradient-based multi-agent coordination control systems
Multi-agent coordination control usually involves a potential function that
encodes information of a global control task, while the control input for
individual agents is often designed by a gradient-based control law. The
property of Hessian matrix associated with a potential function plays an
important role in the stability analysis of equilibrium points in
gradient-based coordination control systems. Therefore, the identification of
Hessian matrix in gradient-based multi-agent coordination systems becomes a key
step in multi-agent equilibrium analysis. However, very often the
identification of Hessian matrix via the entry-wise calculation is a very
tedious task and can easily introduce calculation errors. In this paper we
present some general and fast approaches for the identification of Hessian
matrix based on matrix differentials and calculus rules, which can easily
derive a compact form of Hessian matrix for multi-agent coordination systems.
We also present several examples on Hessian identification for certain typical
potential functions involving edge-tension distance functions and
triangular-area functions, and illustrate their applications in the context of
distributed coordination and formation control
Punishment and Welfare: Paternal Incarceration and Families’ Receipt of Public Assistance
The US criminal justice and welfare systems together form important government interventions into the lives of the poor. This paper considers how imprisonment is related to welfare receipt for offenders and their families. Using longitudinal data from the Fragile Families and Child Wellbeing study, it investigates how recent paternal incarceration is associated with families' receipt of TANF, food stamps, and Medicaid/SCHIP. Results robust to multiple tests find that incarceration does not increase the likelihood of TANF receipt but significantly increases food stamps and Medicaid/SCHIP receipt. Further, the effect of incarceration on welfare receipt is larger than the recent loss of father's employment. The findings suggest that an unexpected consequence of mass imprisonment is the expansion of government regulation through welfare provision for offender's families.Fragile Families and Child Wellbeing study, imprisonment, welfare, criminal justice, welfare system, food stamps, Medicaid/SCHIP, incarceration
Recommended from our members
Employer aversion to criminal records: An experimental study of mechanisms
Recommended from our members
Utilizing Smartphones to Study Disadvantaged and Hard-to-Reach Groups
Mobile technologies, specifically smartphones, offer social scientists a potentially powerful approach to examine the social world. They enable researchers to collect information that was previously unobservable or difficult to measure, expanding the realm of empirical investigation. For research that concerns resource-poor and hard-to-reach groups, smartphones may be particularly advantageous by lessening sample selection and attrition and by improving measurement quality of irregular and unstable experiences. At the same time, smartphones are nascent social science tools, particularly with less advantaged populations that may have different phone usage patterns and privacy concerns. Using findings from a smartphone study of men recently released from prison, this article discusses the strengths and challenges of smartphones as data collection tools among disadvantaged and hard-to-reach groups
- …