Long Island University

About: Long Island University is a education organization based out in Brookville, New York, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 2647 authors who have published 4924 publications receiving 108757 citations.

Fenoldopam in the Prevention of Contrast Media—Induced Acute Renal Failure

Abstract: OBJECTIVE:To examine the role of fenoldopam in prevention of contrast media—induced acute renal failure (ARF).DATA SOURCES:A literature search of MEDLINE (from 1966 to October 2000) was performed using the following title search terms: fenoldopam, contrast, and renal failure.STUDY SELECTION:English-language human studies, abstracts, and pertinent animal data were reviewed.DATA SYNTHESIS:Small trials using animals with artificially induced ARF receiving fenoldopam demonstrated improvement in renal function. Preliminary trials in healthy humans have also demonstrated similar results using doses not affecting systemic blood pressure.CONCLUSIONS:Fenoldopam may have a role in the management of ARF induced by contrast dye. However, due to the lack of a large-scale study, it cannot be routinely recommended.

Holographic sliding stripes

Abstract: Holographic models provide unique laboratories to investigate non-linear physics of transport in inhomogeneous systems. We provide a detailed account of both DC and AC conductivities in a defect CFT with spontaneous stripe order. The spatial symmetry is broken at large chemical potential and the resulting ground state is a combination of a spin and charge density wave. An infinitesimal applied electric field across the stripes will cause the stripes to slide over the underlying density of smeared impurities, a phenomenon which can be associated with the Goldstone mode for the spontaneously broken translation symmetry. We show that the presence of a spatially modulated background magnetization current thwarts the expression of some DC conductivities in terms of horizon data.

Spatial analysis of an invasion front of Acer platanoides: dynamic inferences from static data

Abstract: It is an open question whether the invading tree species Acer platanoides is invading and displacing native trees within pre-existing forest stands, or merely preferentially occupying new stands of secondary forest growth at the edges of existing forests. Several threads of spatial pattern analyses were used to assess the invasibility of A. platanoides, and to link the invasion to the structure of a plant community in the deciduous forest of the northeastern United States. The analyses were based on maps of a contiguous 100×50 m area along an A. platanoides infestation gradient. The distribution of A. platanoides was highly aggregated and the population importance value increased from 28.1 to 38.5% according to mortality estimated from standing dead trees, while the distribution of native tree species was close to random and importance value of Quercus spp. decreased from 33.4 to 26.9% over time. The size distributions of each tree species across distance indicated that A. platanoides was progressively invading the interior of the forest while the native species (including A. rubrum) were not spreading back towards the A. platanoides monospecific patch. The null hypothesis of no invasibility was rejected based on quantile regressions. There were negative correlations between A. platanoides density and the densities of native species in different functional groups, and negative correlation of A. platanoides density and the species diversity in forest understory. The null hypothesis that A. platanoides invasion did not suppress native trees or understory was rejected based on Dutilleul's modified t-test for correlation, consistent with experimental results in the same study site. The combination of multiple spatial analyses of static data can be used to infer historical dynamical processes that shape a plant community structure. The concept of “envelop effects” was discussed and further developed.

Novel Methods for Obtaining High Modulus Aliphatic Polyamide Fibers

Abstract: Super high modulus polyethylene fibers can be created by converting high molecular weight flexible PE chains into highly oriented and extended chain conformations. However, unlike polyethylene, aliphatic polyamides have very high cohesive energy and therefore cannot be easily drawn and highly oriented. This review addresses this fundamental problem by analyzing various novel approaches that can be used to suppress hydrogen bonding in these types of polyamides. Plasticization of such polymers with ammonia, iodine, salts, and Lewis acids, as well as dry spinning, wet spinning, and gel spinning, are discussed. Specialized techniques that involve vibrational zone drawing and annealing as well as laser heating zone drawing and annealing are also reviewed. Some of these methods definitely lead to remarkable improvements in initial modulus and other mechanical properties. The development of recombinant spider silk proteins as well progress in spinning these materials is also reported. The advantages and disadvan...