473 research outputs found
Political Participation of Ethnic Minorities in the 1980s
Currently political participation, especially voter registration and
turnout, varies substantially with ethnicity. Blacks and non-Hispanic whites
participate at roughly equal rates, while Latinos and Asian-Americans are
substantially less active, this variation may reflect cultural factors, or
it may be the spurious product of differences in the distribution of
non-ethnic determinants of participation, including socioeconomic and
demographic characteristics, variables reflecting immigration history,
including citizenship, and measures of group identification. Using data
collected in 1984 on samples of California's black, Latino, Asian-American,
and non-Hispanic white populations, we conclude that these other variables
fully account for lower Latino participation rates. Even with such controls,
however, Asian-Americans remain less likely to vote. Although non-citizens
participate less than citizens, they do engage in non-electoral activities,
Finally, we speculate on the future political impact of Latinos and
Asian-Americans, by projecting participation rates under several scenarios
Thermodynamics of the superfluid dilute Bose gas with disorder
We generalize the Beliaev-Popov diagrammatic technique for the problem of
interacting dilute Bose gas with weak disorder. Averaging over disorder is
implemented by the replica method. Low energy asymptotic form of the Green
function confirms that the low energy excitations of the superfluid dirty Boson
system are sound waves with velocity renormalized by the disorder and
additional dissipation due to the impurity scattering. We find the
thermodynamic potential and the superfluid density at any temperature below the
superfluid transition temperature and derive the phase diagram in temperature
vs. disorder plane.Comment: 4 page
Political Participation of Ethnic Minorities in the 1980s
Currently political participation, especially voter registration and
turnout, varies substantially with ethnicity. Blacks and non-Hispanic whites
participate at roughly equal rates, while Latinos and Asian-Americans are
substantially less active, this variation may reflect cultural factors, or
it may be the spurious product of differences in the distribution of
non-ethnic determinants of participation, including socioeconomic and
demographic characteristics, variables reflecting immigration history,
including citizenship, and measures of group identification. Using data
collected in 1984 on samples of California's black, Latino, Asian-American,
and non-Hispanic white populations, we conclude that these other variables
fully account for lower Latino participation rates. Even with such controls,
however, Asian-Americans remain less likely to vote. Although non-citizens
participate less than citizens, they do engage in non-electoral activities,
Finally, we speculate on the future political impact of Latinos and
Asian-Americans, by projecting participation rates under several scenarios
Effects of Different Human Milk Oligosaccharides on Growth of Bifidobacteria in Monoculture and Co-culture With Faecalibacterium prausnitzii
Human milk oligosaccharides (hMOs) are important bioactive components in mother’s milk contributing to infant health by supporting colonization and growth of gut microbes. In particular, Bifidobacterium genus is considered to be supported by hMOs. Approximately 200 different hMOs have been discovered and characterized, but only a few abundant hMOs can be produced in sufficient amounts to be applied in infant formula. These hMOs are usually supplied in infant formula as single molecule, and it is unknown which and how individual hMOs support growth of individual gut bacteria. To investigate how individual hMOs influence growth of several relevant intestinal bacteria species, we studied the effects of three hMOs (2′-fucosyllactose, 3-fucosyllactose, and 6′-sialyllactose) and an hMO acid hydrolysate (lacto-N-triose) on three Bifidobacteria and one Faecalibacterium and introduced a co-culture system of two bacterial strains to study possible cross-feeding in presence and absence of hMOs. We observed that in monoculture, Bifidobacterium longum subsp. infantis could grow well on all hMOs but in a structure-dependent way. Faecalibacterium prausnitzii reached a lower cell density on the hMOs in stationary phase compared to glucose, while B. longum subsp. longum and Bifidobacterium adolescentis were not able to grow on the tested hMOs. In a co-culture of B. longum subsp. infantis with F. prausnitzii, different effects were observed with the different hMOs; 6′-sialyllactose, rather than 2′-fucosyllactose, 3-fucosyllactose, and lacto-N-triose, was able to promote the growth of B. longum subsp. infantis. Our observations demonstrate that effects of hMOs on the tested gut microbiota are hMO-specific and provide new means to support growth of these specific beneficial microorganisms in the intestine.</p
Towards Next-Generation Sequencing (NGS)-Based Newborn Screening:A Technical Study to Prepare for the Challenges Ahead
Newborn screening (NBS) aims to identify neonates with severe conditions for whom immediate treatment is required. Currently, a biochemistry-first approach is used to identify these disorders, which are predominantly inherited metalbolic disorders (IMD). Next-generation sequencing (NGS) is expected to have some advantages over the current approach, for example the ability to detect IMDs that meet all screening criteria but lack an identifiable biochemical footprint. We have now designed a technical study to explore the use of NGS techniques as a first-tier approach in NBS. Here, we describe the aim and set-up of the NGS-first for the NBS (NGSf4NBS) project, which will proceed in three steps. In Step 1, we will identify IMDs eligible for NGS-first testing, based on treatability. In Step 2, we will investigate the feasibility, limitations and comparability of different technical NGS approaches and analysis workflows for NBS, eventually aiming to develop a rapid NGS-based workflow. Finally, in Step 3, we will prepare for the incorporation of this workflow into the existing Dutch NBS program and propose a protocol for referral of a child after a positive NGS test result. The results of this study will be the basis for an additional analytical route within NBS that will be further studied for its applicability within the NBS program, e.g., regarding the ethical, legal, financial and social implications.</p
Dynamics of liquid 4He in Vycor
We have measured the dynamic structure factor of liquid 4He in Vycor using
neutron inelastic scattering. Well-defined phonon-roton (p-r) excitations are
observed in the superfluid phase for all wave vectors 0.3 < Q < 2.15. The p-r
energies and lifetimes at low temperature (T = 0.5 K) and their temperature
dependence are the same as in bulk liquid 4He. However, the weight of the
single p-r component does not scale with the superfluid fraction (SF) as it
does in the bulk. In particular, we observe a p-r excitation between T_c =
1.952 K, where SF = 0, and T_(lambda)=2.172 K of the bulk. This suggests, if
the p-r excitation intensity scales with the Bose condensate, that there is a
separation of the Bose-Einstein condensation temperature and the superfluid
transition temperature T_c of 4He in Vycor. We also observe a two-dimensional
layer mode near the roton wave vector. Its dispersion is consistent with
specific heat and SF measurements and with layer modes observed on graphite
surfaces.Comment: 3 pages, 4 figure
Modeling focal epileptic activity in the Wilson-Cowan model with depolarization block
Measurements of neuronal signals during human seizure activity and evoked epileptic activity in experimental models suggest that, in these pathological states, the individual nerve cells experience an activity driven depolarization block, i.e. they saturate. We examined the effect of such a saturation in the Wilson–Cowan formalism by adapting the nonlinear activation function; we substituted the commonly applied sigmoid for a Gaussian function. We discuss experimental recordings during a seizure that support this substitution. Next we perform a bifurcation analysis on the Wilson–Cowan model with a Gaussian activation function. The main effect is an additional stable equilibrium with high excitatory and low inhibitory activity. Analysis of coupled local networks then shows that such high activity can stay localized or spread. Specifically, in a spatial continuum we show a wavefront with inhibition leading followed by excitatory activity. We relate our model simulations to observations of spreading activity during seizures
Effect of random on-site energies on the critical temperature of a lattice Bose gas
We study the effect of random on-site energies on the critical temperature of
a non-interacting Bose gas on a lattice. In our derivation the on-site energies
are distributed according a Gaussian probability distribution function having
vanishing average and variance . By using the replicated action obtained
by averaging on the disorder, we perform a perturbative expansion for the Green
functions of the disordered system. We evaluate the shift of the chemical
potential induced by the disorder and we compute, for , the
critical temperature for condensation. We find that, for large filling,
disorder slightly enhances the critical temperature for condensation.Comment: To appear in Laser Physics, issue on the LPHYS'08 conference
(Trondheim, 2008
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