197,738 research outputs found
The Importance of Developmental Science for Studies in Bullying and Victimization
Research on bullying and victimization, especially in school settings, has become an important area of developmental research, with strong practical implications. In this article we overview some considerations from neuropsychology, quantitative genetics, developmental neuroscience, we discuss CU traits and conduct problems, individual, group, class and school levels of analysis, developmental changes by age and context, and cross-cultural aspects. Together we argue that these can help bring about a developmental science perspective on to this area of research
A simple model for the kinetics of packaging of DNA in to a capsid against an external force
We propose a simple model for the kinetics of packaging of viral DNA in to a
capsid against an external force trying to prevent it. The model leads to a
Butler-Volmer type dependence of the rate of packaging on the pulling force F
Closed cycle electric discharge laser design investigation
Closed cycle CO2 and CO electric discharge lasers were studied. An analytical investigation assessed scale-up parameters and design features for CO2, closed cycle, continuous wave, unstable resonator, electric discharge lasing systems operating in space and airborne environments. A space based CO system was also examined. The program objectives were the conceptual designs of six CO2 systems and one CO system. Three airborne CO2 designs, with one, five, and ten megawatt outputs, were produced. These designs were based upon five minute run times. Three space based CO2 designs, with the same output levels, were also produced, but based upon one year run times. In addition, a conceptual design for a one megawatt space based CO laser system was also produced. These designs include the flow loop, compressor, and heat exchanger, as well as the laser cavity itself. The designs resulted in a laser loop weight for the space based five megawatt system that is within the space shuttle capacity. For the one megawatt systems, the estimated weight of the entire system including laser loop, solar power generator, and heat radiator is less than the shuttle capacity
Charge exchange lifetimes for ions in the magnetosphere
Latest and best measurements of physical quantities involved in complete calculation of the charge exchange lifetime of mirroring magnetospheric ions are coalesced and summarized. It is critical that the charge exchange lifetimes for ions be known as accurately as possible in order to apply the charge exchange mechanism to ion phenomena within the earth's magnetosphere
Kinematics of a large-scale intraplate extending lithosphere: The Basin-Range
Upper lithospheric structure of the Cordilleran Basin Range (B-R) is characterised by an E-W symmetry of velocity layering. The crust is 25 km thick on its eastern active margin, thickening to 30 km within the central portion and thinning to approx. 25 km on the west. Pn velocities of 7.8 to 7.9 km/s characterize the upper mantle low velocity cushion, 7.4 km/s to 7.5 km/s, occurs at a depth of approx. 25 km in the eastern B-R and underlies the area of active extension. An upper-crustal low-velocity zone in the eastern B-R shows a marked P-wave velocity inversion of 7% at depths of 7 to 10 km also in the area of greatest extension. The seismic velocity models for this region of intraplate extension suggest major differences from that of a normal, thermally underformed continental lithosphere. Interpretations of seismic reflection data demonstrate the presence of extensive low-angle reflections in the upper-crust of the eastern B-R at depths from near-surface to 7 to 10 km. These reflections have been interpreted to represent low-angle normal fault detachments or reactivated thrusts. Seismic profiles across steeply-dipping normal faults in unconsolidated sediments show reflections from both planar to downward flatening (listric) faults that in most cases do not penetrate the low-angle detachments. These faults are interpreted as late Cenozoic and cataclastic mylonitic zones of shear displacement
Dependence of the charge exchange lifetimes on mirror latitude
The dependence of the charge exchange lifetimes on the mirror latitude for ions mirroring off the geomagnetic equator was re-computed using the improved hydrogen distribution models. The Chamberlain model was used to define the spatial distribution of the neutral hydrogen environment through which the ring current ions traverse. The resultant dependence of the charge exchange lifetime on mirror latitude is best fitted by the approximation that contains the charge exchange lifetime for equatorial particles
CHANDRA Observations of the X-ray Halo around the Crab Nebula
Two Chandra observations have been used to search for thermal X-ray emission
from within and around the Crab Nebula. Dead-time was minimized by excluding
the brightest part of the Nebula from the field of view. A dust-scattered halo
comprising 5% of the strength of the Crab is clearly detected with surface
brightness measured out to a radial distance of 18 arcminutes. Coverage is 100%
at 4 arcminutes, 50% at 12 arcminutes, and 25% at 18 arcminutes. The observed
halo is compared with predictions based on 3 different interstellar grain
models and one can be adjusted to fit the observation. This dust halo and
mirror scattering form a high background region which has been searched for
emission from shock-heated material in an outer shell. We find no evidence for
such emission. We can set upper limits a factor of 10-1000 less than the
surface brightness observed from outer shells around similar remnants. The
upper limit for X-ray luminosity of an outer shell is about 10e34 erg/s.
Although it is possible to reconcile our observation with an 8-13 solar mass
progenitor, we argue that this is unlikely.Comment: 26 pages, 12 figures, accepted by Ap
The Changing Economic Status of U.S. Disabled Men: Trends and Their Determinants, 1982–1991
In this paper, we track the level of economic well-being of the population of men who began receiving Social Security Disability Insurance (SSDI) benefits in 1980–81 from the time just after they became beneficiaries (in 1982) to 1991, nearly a decade later. We present measures of the economic well-being of disabled individuals and their nondisabled peers as indicators of the relative economic position of these two groups. These measures also provide an intertemporal comparison of well-being and hardship as disabled persons and their nondisabled peers age and retire. We first show several economic well-being indicators for this group of new male recipients of disability benefits in 1982 and 1991. Then, we compare their economic position to that of a matched group of nondisabled males with sufficient work histories to have been disability-insured, that is, eligible for SSDI benefits had they been unable to engage in substantial gainful employment. Because labor market changes over this decade have led to a relative deterioration in the position of younger and less-educated workers, we compare men with disabilities to those without disabilities and distinguish different age and educational levels within the groups. In studying these comparative trends in well-being, we focus on the prevalence of poverty and its correlates. We conclude by assessing the antipoverty effectiveness of Social Security income support for both younger and older men who became SSDI recipients in 1980–81.
The Changing Economic Status of Disabled Women, 1982–1991: Trends and Their Determinants
This study provides an assessment of the intertemporal economic well-being of a representative sample of women who began receiving Social Security Disability Insurance (SSDI) in 1980–81. We compare their economic circumstances over the 1982–1991 period with those of disabled men who also began receiving SSDI in those years and with those of a matched sample of nondisabled women who had sufficient work experience for benefit eligibility should they have become disabled. In 1982, the new SSDI women beneficiaries were a relatively poor segment of U.S. society: one quarter of them lived in poverty and 48 percent had incomes below 150 percent of the poverty line. As of 1991, over one-half of these disabled women lived in families with income below 150 percent of the poverty line. Social Security benefits to disabled women have played an important, and growing, role in sustaining economic status. Nevertheless, the level of well-being of these women lies substantially below that of the comparison groups. We statistically relate the poverty status of these new female recipients to sociodemographic factors that would be expected to contribute to lower levels of well-being, and we simulate the effect of Social Security benefits in reducing poverty and replacing earnings. We suggest a number of SSDI-related policy changes that could, at low cost, reduce poverty among the poorest women.
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