1,199 research outputs found
A comparison of the growth kinetics of six marine heterotrophic nanoflagellates fed with one bacterial species.
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The Intersections of Race, Gender, Age, and Socioeconomic Status: Implications for Reporting Discrimination and Attributions to Discrimination.
This study employed an intersectional approach (operationalized as the combination of more than one social identity) to examine the relationship between aspects of social identity (i.e., race, gender, age, SES), self-reported level of mistreatment, and attributions for discrimination. Self-reported discrimination has been researched extensively and there is substantial evidence of its association with adverse physical and psychological health outcomes. Few studies, however, have examined the relationship of multiple demographic variables (including social identities) to overall levels self-reported mistreatment as well the selection of attributions for discrimination. A diverse community sample (N = 292; 42.12% Black; 47.26% male) reported on experiences of discrimination using the Everyday Discrimination Scale. General linear models were used to test the effect of sociodemographic characteristics (i.e., race, gender, age, SES) on total discrimination score and on attributions for discrimination. To test for intersectional relationships, we tested the effect of two-way interactions of sociodemographic characteristics on total discrimination score and attributions for discrimination. We found preliminary support for intersectional effects, as indicated by a significant race by age interaction on the selection of the race attribution for discrimination; gender by SES on the age attribution; age by gender on the education attribution; and race by SES on the economic situation attribution. Our study extends prior work by highlighting the importance of testing more than one factor as contributing to discrimination, particularly when examining to what sources individuals attribute discrimination
SOME RESULTS ON THE DESIGN OF EXPERIMENTS FOR COMPARING UNREPLICATED TREATMENTS
In early generation variety trials, large numbers of new varieties may be compared, and little seed is usually available for each variety. A so-called unreplicated trial has each new variety on just one plot at a site, but includes several (often around 5) replicated check or control (or standard) varieties. The total proportion of check plots is usually between 10% and 20%. The aim of the trial is to choose some (around 1/3) good performing varieties to go on for further testing, rather than precise estimation of their mean yield.
Now that spatial analyses of data from field experiments are becoming more common, there is interest in an efficient layout of an experiment given a proposed spatial analysis. Some possible design criteria are discussed, and efficient layouts under spatial dependence are considered
Spin Dynamics in the Magnetic Chains Arrays of Sr14Cu24O41: a Neutron Inelastic scattering Investigation
Below about 150 K, the spin arrangement in the chain arrays of Sr14Cu24O41 is
shown to develop in two dimensions (2D). Both the correlations and the
dispersion of the observed elementary excitations agree well with a model of
interacting dimers. Along the chains, the intra- and inter-dimer distances are
equal to 2 and about 3 times the distance (c) between neighboring Cu ions.
While the intra-dimer coupling is J about 10 meV, the inter-dimer couplings
along and between the chains are of comparable strenght, J// about -1.1 meV and
Jperp about 1.7 meV, respectively. This remarkable 2D arrangement satisfies the
formal Cu valence of the undoped compound. Our data suggest also that it is
associated with a relative sliding of one chain with respect to the next one,
which, as T decreases, develops in the chain direction. A qualitative analysis
shows that nearest inter-dimer spin correlations are ferromagnetic, which, in
such a 2D structure, could well result from frustration effects.Comment: 4 pages, 5 figures, submitted to Phys.Rev.B, date of receipt 29 June
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Dynamic Spin Response for Heisenberg Ladders
We employ the recently proposed plaquette basis to investigate static and
dynamic properties of isotropic 2-leg Heisenberg spin ladders. Simple
non-interacting multi-plaquette states provide a remarkably accurate picture of
the energy/site and dynamic spin response of these systems. Insights afforded
by this simple picture suggest a very efficient truncation scheme for more
precise calculations. When the small truncation errors are accounted for using
recently developed Contractor Renormalization techniques, very accurate results
requiring a small fraction of the computational effort of exact calculations
are obtained. These methods allow us to determine the energy/site, gap, and
spin response of 2x16 ladders. The former two values are in good agreement with
density matrix renormalization group results. The spin response calculations
show that nearly all the strength is concentrated in the lowest triplet level
and that coherent many-body effects enhance the response/site by nearly a
factor of 1.6 over that found for 2x2 systems.Comment: 9 pages with two enclosed postscript figure
Antiferromagnetic S=1/2 Heisenberg Chain and the Two-flavor Massless Schwinger Model
An antiferromagnetic S=1/2 Heisenberg chain is mapped to the two-flavor
massless Schwinger model at \theta=\pi. The electromagnetic coupling constant
and velocity of light in the Schwinger model are determined in terms of the
Heisenberg coupling and lattice spacing in the spin chain system.Comment: 3 pages. LaTex2
Assessing the quality of walking in adults with chronic pain: The development and preliminary psychometric evaluation of the Bath Assessment of Walking Inventory
Phases of two coupled Luttinger liquids
A model of two interacting one--dimensional fermion systems (``Luttinger
liquids'') coupled by single--particle hopping is investigated. Bosonization
allows a number of exact statements to be made. In particular, for forward
scattering only, the model contains two massless boson sectors and an Ising
type critical sector. For general interactions, there is a spin excitation gap
and either s-- or d--type pairing fluctuations dominate. It is shown that the
same behavior is also found for strong interactions. A possible scenario for
the crossover to a Fermi liquid in a many chain system is discussed.Comment: revised version, some changes, 11 pages, no figures, RexTeX3.
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