4,575 research outputs found
Supersymmetric Higgs singlet effects on FCNC observables
Higgs singlet superfields, usually present in extensions of the Minimal
Supersymmetric Standard Model (MSSM) which address the -problem, such as
the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and the Minimal
Nonminimal Supersymmetric Standard Model (mnSSM), can have significant
contributions to -meson flavour-changing neutral current observables for
large values of \tan\beta \gsim 50. Illustrative results are presented
including effects on the and on the rare decay . In
particular, we find that in the NMSSM, the branching ratio for
can be enhanced or even suppressed with respect to the
Standard Model prediction by more than one order of magnitude.Comment: 3 pages, 4 figures, submitted to SUSY08 proceeding
Finite-element reentry heat-transfer analysis of space shuttle Orbiter
A structural performance and resizing (SPAR) finite-element thermal analysis computer program was used in the heat-transfer analysis of the space shuttle orbiter subjected to reentry aerodynamic heating. Three wing cross sections and one midfuselage cross section were selected for the thermal analysis. The predicted thermal protection system temperatures were found to agree well with flight-measured temperatures. The calculated aluminum structural temperatures also agreed reasonably well with the flight data from reentry to touchdown. The effects of internal radiation and of internal convection were found to be significant. The SPAR finite-element solutions agreed reasonably well with those obtained from the conventional finite-difference method
Thermal Expansion in Dispersion-Bound Molecular Crystals
We explore how anharmonicity, nuclear quantum effects (NQE), many-body
dispersion interactions, and Pauli repulsion influence thermal properties of
dispersion-bound molecular crystals. Accounting for anharmonicity with
molecular dynamics yields cell parameters accurate to within 2% of
experiment for a set of pyridine-like molecular crystals at finite temperatures
and pressures. From the experimental thermal expansion curve, we find that
pyridine-I has a Debye temperature just above its melting point, indicating
sizable NQE across the entire crystalline range of stability. We find that NQE
lead to a substantial volume increase in pyridine-I (% more than
classical thermal expansion at K) and attribute this to intermolecular
Pauli repulsion promoted by intramolecular quantum fluctuations. When
predicting delicate properties such as the thermal expansivity, we show that
many-body dispersion interactions and sophisticated treatments of Pauli
repulsion are needed in dispersion-bound molecular crystals
Trauma histories among justice-involved youth: findings from the National Child Traumatic Stress Network.
BackgroundUp to 90% of justice-involved youth report exposure to some type of traumatic event. On average, 70% of youth meet criteria for a mental health disorder with approximately 30% of youth meeting criteria for post-traumatic stress disorder (PTSD). Justice-involved youth are also at risk for substance use and academic problems, and child welfare involvement. Yet, less is known about the details of their trauma histories, and associations among trauma details, mental health problems, and associated risk factors.ObjectiveThis study describes detailed trauma histories, mental health problems, and associated risk factors (i.e., academic problems, substance/alcohol use, and concurrent child welfare involvement) among adolescents with recent involvement in the juvenile justice system.MethodThe National Child Traumatic Stress Network Core Data Set (NCTSN-CDS) is used to address these aims, among which 658 adolescents report recent involvement in the juvenile justice system as indexed by being detained or under community supervision by the juvenile court.ResultsAge of onset of trauma exposure was within the first 5 years of life for 62% of youth and approximately one-third of youth report exposure to multiple or co-occurring trauma types each year into adolescence. Mental health problems are prevalent with 23.6% of youth meeting criteria for PTSD, 66.1% in the clinical range for externalizing problems, and 45.5% in the clinical range for internalizing problems. Early age of onset of trauma exposure was differentially associated with mental health problems and related risk factors among males and females.ConclusionsThe results indicate that justice-involved youth report high rates of trauma exposure and that this trauma typically begins early in life, is often in multiple contexts, and persists over time. Findings provide support for establishing trauma-informed juvenile justice systems that can respond to the needs of traumatized youth
Comparison of flight-measured and calculated temperatures on the space shuttle orbiter
Structural temperatures and thermal protection system surface temperatures were measured on the space shuttle during the flight of STS 5. The measured data are compared with values calculated at wing stations 134, 240, and 328 and at fuselage station 877. The theoretical temperatures were calculated using the structural performance and resizing finite element thermal analysis program. The comparisons show that the calculated temperatures are, generally, in good agreement with the measured data
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Changing home care aides: Differences between family and non-family care in California Medicaid home and community-based services.
In California Medicaid home-and-community-based services (HCBS), recipients' family members receive payment as home care aides (HCAs). We analyzed data on first-time HCBS recipients to examine factors associated with the likelihood of switching HCAs within the first year of services. Those with family HCAs were less than half as likely to change than those with non-family HCAs and racial/ethnic minorities with non-family HCAs had the highest switching rates. Lower wages and local unemployment were associated with switching of non-family HCAs but not family HCAs. Policymakers can foster continuity of home care by paying family members for home care and raising worker wages
Phase Diagram of Vertically Shaken Granular Matter
A shallow, vertically shaken granular bed in a quasi 2-D container is studied
experimentally yielding a wider variety of phenomena than in any previous
study: (1) bouncing bed, (2) undulations, (3) granular Leidenfrost effect, (4)
convection rolls, and (5) granular gas. These phenomena and the transitions
between them are characterized by dimensionless control parameters and combined
in a full experimental phase diagram.Comment: 11 pages, 14 figures, submitted to "Physics of Fluids
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