4,347 research outputs found
Space Transportation Materials and Structures Technology Workshop
The Space Transportation Materials and Structures Technology Workshop was held on September 23-26, 1991, in Newport News, Virginia. The workshop, sponsored by the NASA Office of Space Flight and the NASA Office of Aeronautics and Space Technology, was held to provide a forum for communication within the space materials and structures technology developer and user communities. Workshop participants were organized into a Vehicle Technology Requirements session and three working panels: Materials and Structures Technologies for Vehicle Systems, Propulsion Systems, and Entry Systems
Competing itinerant and localized states in strongly correlated BaVS
The electronic structure of the quasi-lowdimensional vanadium sulfide \bavs3
is investigated for the different phases above the magnetic ordering
temperature. By means of density functional theory and its combination with
dynamical-mean field theory, we follow the evolution of the relevant low-energy
electronic states on cooling. Hence we go in the metallic regime from the room
temperature hexagonal phase to the orthorhombic phase after the first
structural transition, and close with the monoclinic insulating phase below the
metal-insulator transition. Due to the low symmetry and expected intersite
correlations, the latter phase is treated within cellular dynamical mean-field
theory. It is generally discussed how the intriguing interplay between
band-structure and strong-correlation effects leads to the stabilization of the
various electronic phases with decreasing temperature.Comment: 12 pages, submitted to PR
Corn and oats experiments, 1893.
Caption title.Experiments with corn / G.E. Morrow, F.D. Gardner -- Rate of growth and chemical composition of the corn plant / E.H. Farrington -- Experiments with oats, 1893 / G.E. Morrow, F.D. Gardner
Prospective Comparison of Arterial Catheter Blood and Catheter-Tip Cultures in Critically Ill Patients
journal articleBiomedical Informatic
The Risk of Infection Related to Radial vs Femoral Sites for Arterial Catheterization
journal articleBiomedical Informatic
Demography and the tragedy of the commons
Individual success in group-structured populations has two components. First,
an individual gains by outcompeting its neighbors for local resources. Second,
an individual's share of group success must be weighted by the total
productivity of the group. The essence of sociality arises from the tension
between selfish gains against neighbors and the associated loss that
selfishness imposes by degrading the efficiency of the group. Without some
force to modulate selfishness, the natural tendencies of self interest
typically degrade group performance to the detriment of all. This is the
tragedy of the commons. Kin selection provides the most widely discussed way in
which the tragedy is overcome in biology. Kin selection arises from behavioral
associations within groups caused either by genetical kinship or by other
processes that correlate the behaviors of group members. Here, I emphasize
demography as a second factor that may also modulate the tragedy of the commons
and favor cooperative integration of groups. Each act of selfishness or
cooperation in a group often influences group survival and fecundity over many
subsequent generations. For example, a cooperative act early in the growth
cycle of a colony may enhance the future size and survival of the colony. This
time-dependent benefit can greatly increase the degree of cooperation favored
by natural selection, providing another way in which to overcome the tragedy of
the commons and enhance the integration of group behavior. I conclude that
analyses of sociality must account for both the behavioral associations of kin
selection theory and the demographic consequences of life history theory
Developmental associations between victimization and body mass index from 3 to 10 years in a population sample
In the current prospective study, we investigated (1) whether high and low BMI in early childhood puts a child at risk of victimization by their peers, and (2) whether being victimised increases BMI over the short- and long-term, independent of the effect of BMI on victimization. We also examined whether gender moderated these prospective associations. Participants were 1344 children who were assessed yearly from ages 3 -10 years as part of the Québec Longitudinal Study of Child Development (QLSCD). BMI predicted annual increases in victimization for girls aged 6 years and over; for boys aged 7 and 8 years of age, higher BMI reduced victimization over the school year. Further, victimization predicted annual increases in BMI for girls after age 6 years. When these short-term effects were held constant, victimization was also shown to have a three and five-year influence on annual BMI changes for girls from age 3 years. These short- and long-term cross-lagged effects were evident when the effects of family adversity were controlled. The findings support those from previous prospective research showing a link between higher BMI and victimization, but only for girls. Further, being victimised increased the likelihood that girls would put on weight over time, which then increased future victimization. The implications of these prospective findings for interventions are considered
- …