A global data set of soil particle size properties

A standardized global data set of soil horizon thicknesses and textures (particle size distributions) was compiled. This data set will be used by the improved ground hydrology parameterization designed for the Goddard Institute for Space Studies General Circulation Model (GISS GCM) Model 3. The data set specifies the top and bottom depths and the percent abundance of sand, silt, and clay of individual soil horizons in each of the 106 soil types cataloged for nine continental divisions. When combined with the World Soil Data File, the result is a global data set of variations in physical properties throughout the soil profile. These properties are important in the determination of water storage in individual soil horizons and exchange of water with the lower atmosphere. The incorporation of this data set into the GISS GCM should improve model performance by including more realistic variability in land-surface properties

Regenerating Corticospinal Axons Innervate Phenotypically Appropriate Neurons within Neural Stem Cell Grafts.

Neural progenitor cell grafts form new relays across sites of spinal cord injury (SCI). Using a panel of neuronal markers, we demonstrate that spinal neural progenitor grafts to sites of rodent SCI adopt diverse spinal motor and sensory interneuronal fates, representing most neuronal subtypes of the intact spinal cord, and spontaneously segregate into domains of distinct cell clusters. Host corticospinal motor axons regenerating into neural progenitor grafts innervate appropriate pre-motor interneurons, based on trans-synaptic tracing with herpes simplex virus. A human spinal neural progenitor cell graft to a non-human primate also received topographically appropriate corticospinal axon regeneration. Thus, grafted spinal neural progenitor cells give rise to a variety of neuronal progeny that are typical of the normal spinal cord; remarkably, regenerating injured adult corticospinal motor axons spontaneously locate appropriate motor domains in the heterogeneous, developing graft environment, without a need for additional exogenous guidance

From Illegal to Legal: Estimating Previous Illegal Experience among New Legal Immigrants to the United States

This paper develops a framework for estimating previous illegal experience among annual cohorts of new legal immigrants to the United States – using public-use administrative microdata alone, survey data alone, and the two jointly – and provides estimates for the FY 1996 cohort of new immigrants, based on both administrative and survey data. Our procedures enable assessment of type of illegal experience, including entry without inspection, visa overstay, and unauthorized employment. We compare our estimates of previous illegal experience to estimates that would be obtained using administrative data alone; examine the extent of previous illegal experience by country of birth, immigrant class of admission, religion, and geographic residence in the United States; and estimate multivariate models of the probability of having previous illegal experience. To further assess origins and destinations, we carry out two kinds of contrasts, comparing formerly illegal new legal immigrants both to fellow immigrants who do not have previous illegal experience and also to the broader unauthorized population, the latter using estimates developed by DHS (2002), Passel (2002), and Costanzo et al. (2002).administrative data, legal immigration, illegal immigration, survey data

Immigration, health, and New York City: early results based on the U.S. new immigrant cohort of 2003

This article was presented at a conference organized by the Federal Reserve Bank of New York in April 2005, "Urban Dynamics in New York City." The goal of the conference was threefold: to examine the historical transformations of the engine-of-growth industries in New York and distill the main determinants of the city's historical dominance as well as the challenges to its continued success; to study the nature and evolution of immigration flows into New York; and to analyze recent trends in a range of socioeconomic outcomes, both for the general population and recent immigrants more specifically.Immigrants - New York (N.Y.) ; Medical care - New York (N.Y.) ; Economic conditions - New York (N.Y.) ; Federal Reserve District, 2nd

Immigrant Health--Selectivity and Acculturation

This paper explores some salient issues concerning immigrant health. Ethnic health disparities are inherently linked to immigration since ethnic identities often are traced to the country of origin of one's immigrant ancestors. Two of the central questions that have dominated the medical and social science literature on immigrant health are the central focus of this paper. These issues involve the magnitude and mechanisms shaping health selectivity and the determinants of health trajectories following immigration. As part of this paper, we also developed a theoretical model that attempts to explain the diversity in health selection among immigrants.

Analytical treatment of the wakefields driven by transversely shaped beams in a planar slow-wave structure

The suppression of transverse wakefield effects using transversely elliptical drive beams in a planar structure is studied with a simple analytical model that unveils the geometric nature of this phenomenon. By analyzing the suggested model we derive scaling laws for the amplitude of the longitudinal and transverse wake potentials as a function of the Gaussian beam ellipticity - $\sigma_x/a$. We explicitly show that in a wakefield accelerator application it is beneficial to use highly elliptical beams for mitigating transverse forces while maintaining the accelerating field. We consider two scaling strategies: 1) aperture scaling, where we keep a constant charge to have the same accelerating gradient as in a cylindrical structure and 2) charge scaling, where aperture is the same as in the cylindrical structure and charge is increased to match the gradient.Comment: 10 pages, 6 figure