1,601 research outputs found
Is There Extra Cost of Institutional Care for MS Patients?
Throughout life, patients with multiple sclerosis (MS) require increasing levels of support, rehabilitative services, and eventual skilled nursing facility (SNF) care. There are concerns that access to SNF care for MS patients is limited because of perceived higher costs of their care. This study compares costs of caring for an MS patient versus those of a typical SNF patient. We merged SNF cost report data with the 2001-2006 Nursing Home Minimum Data Set (MDS) to calculate percentage of MS residents-days and facility case-mix indices (CMIs). We estimated the average facility daily cost using hybrid cost functions, adjusted for facility ownership, average facility wages, CMI-adjusted number of SNF days, and percentage of MS residents-days. We describe specific characteristics of SNF with high and low MS volumes and examine any sources of variation in cost. MS patients were no longer more costly than typical SNF patients. A greater proportion of MS patients had no significant effect on facility daily costs (P = 0.26). MS patients were more likely to receive care in government-owned facilities (OR = 1.904) located in the Western (OR = 2.133) and Midwestern (OR = 1.3) parts of the USA (P < 0.05). Cost of SNF care is not a likely explanation for the perceived access barriers that MS patients face
Chemical Evolution of the Galactic Bulge as Derived from High-Resolution Infrared Spectroscopy of K and M Red Giants
We present chemical abundances in K and M red-giant members of the Galactic
bulge derived from high-resolution infrared spectra obtained with the Phoenix
spectrograph on Gemini-South. The elements studied are carbon, nitrogen,
oxygen, sodium, titanium, and iron. The evolution of C and N abundances in the
studied red-giants show that their oxygen abundances represent the original
values with which the stars were born. Oxygen is a superior element for probing
the timescale of bulge chemical enrichment via [O/Fe] versus [Fe/H]. The
[O/Fe]-[Fe/H] relation in the bulge does not follow the disk relation, with
[O/Fe] values falling above those of the disk. Titanium also behaves similarly
to oxygen with respect to iron. Based on these elevated values of [O/Fe] and
[Ti/Fe] extending to large Fe abundances, it is suggested that the bulge
underwent a more rapid chemical enrichment than the halo. In addition, there
are declines in both [O/Fe] and [Ti/Fe] in those bulge targets with the largest
Fe abundances, signifying another source affecting chemical evolution: perhaps
Supernovae of Type Ia. Sodium abundances increase dramatically in the bulge
with increasing metallicity, possibly reflecting the metallicity dependant
yields from supernovae of Type II, although Na contamination from H-burning in
intermediate mass stars cannot be ruled out.Comment: ApJ in pres
The Stellar Parameters and Evolutionary State of the Primary in the d'-Symbiotic System StH\alpha190
We report on a high-resolution, spectroscopic stellar parameter and abundance
analysis of a d' symbiotic star: the yellow component of StH\alpha190. This
star has recently been discovered, and confirmed here, to be a rapidly rotating
(vsini=100 km/s) subgiant, or giant, that exhibits radial-velocity variations
of probably at least 40 km/s, indicating the presence of a companion (a white
dwarf star). It is found that the cool stellar component has Teff=5300K and log
g=3.0. The iron and calcium abundances are close to solar, however, barium is
overabundant, relative to Fe and Ca, by about +0.5 dex. The barium enhancement
reflects mass-transfer of s-process enriched material when the current white
dwarf was an asymptotic giant branch (AGB) star. The past and future evolution
of this binary system depends critically on its current orbital period, which
is not yet known. Concerted and frequent radial-velocity measurements are
needed to provide crucial physical constraints to this d' symbiotic system.Comment: 9 pages, 1 table, 3 figures. In press to Astrophysical Journal
Letter
Evidence for a GABAergic system in rodent and human testis: Local GABA production and GABA receptors
The major neurotransmitter of the central nervous system, gamma-aminobutyric acid (GABA), exerts its actions through GABA(A), GABA(B) and GABA(C) receptors. GABA and GABA receptors are, however, also present in several non-neural tissues, including the endocrine organs pituitary, pancreas and testis. In the case of the rat testis, GABA appears to be linked to the regulation of steroid synthesis by Leydig cells via GABA(A) receptors, but neither testicular sources of GABA, nor the precise nature of testicular GABA receptors are fully known. We examined these points in rat, mouse, hamster and human testicular samples. RT-PCR followed by sequencing showed that the GABA-synthesizing enzymes glutamate decarboxylase (GAD) 65 and/or GAD67, as well as the vesicular GABA transporter vesicular inhibitory amino acid transporter (VIAAT/VGAT) are expressed. Testicular GAD in the rat was shown to be functionally active by using a GAD assay, and Western blot analysis confirmed the presence of GAD65 and GAD67. Interstitial cells, most of which are Leydig cells according to their location and morphological characteristics, showed positive immunoreaction for GAD and VIAAT/VGAT proteins. In addition, several GABA(A) receptor subunits (alpha1-3, beta1-3, gamma1-3), as well as GABAB receptor subunits R1 and R2, were detected by RT-PCR. Western blot analysis confirmed the results for GABA(A) receptor subunits beta2/3 in the rat, and immunohistochemistry identified interstitial Leydig cells to possess immunoreactive GABA(A) receptor subunits beta2/3 and alpha1. The presence of GABA(A) receptor subunit alpha1 mRNA in interstitial cells of the rat testis was further shown after laser microdissection followed by RT-PCR analysis. In summary, these results describe molecular details of the components of an intratesticular GABAergic system expressed in the endocrine compartment of rodent and human testes. While the physiological significance of this peripheral neuroendocrine system conserved throughout species remains to be elucidated, its mere presence in humans suggests the possibility that clinically used drugs might be able to interfere with testicular function. Copyright (C) 2003 S. Karger AG, Basel
The Observed Trend of Boron and Oxygen in Field Stars of the Disk
Oxygen abundances are derived in a sample of 13 field F and G dwarfs and
subgiants with metallicities in the range of -0.75 < [Fe/H] < +0.15. This is
the same sample of stars for which boron abundances have been derived earlier
from archived spectra obtained with the Hubble Space Telescope. In a log-log
comparison of the B versus the O abundances, a slope of m(BO)=1.39 is found,
indicating that in the disk, the abundance of B relative to O is intermediate
between primary and secondary production (hybrid behavior). This relation of B
versus O for disk stars is compared to the same relation for halo stars.Comment: 14 pages, 3 figures, 1 table. In press to The Astronomical Journal
(July 2001
Fluorine Abundances in the Globular Cluster M 4
We present chemical abundances for the elements carbon, sodium, and fluorine
in 15 red giants of the globular cluster M 4, as well as six red giants of the
globular cluster Centauri. The chemical abundances were calculated in
LTE via spectral synthesis. The spectra analyzed are high-resolution spectra
obtained in the near-infrared region around 2.3m with the Phoenix
spectrograph on the 8.1m Gemini South Telescope, the IGRINS spectrograph on the
McDonald Observatory 2.7m Telescope, and the CRIRES spectrograph on the ESO
8.2m Very Large Telescope. The results indicate a significant reduction in the
fluorine abundances when compared to previous values from the literature for M
4 and Centauri, due to a downward revision in the excitation
potentials of the HF(1-0) R9 line used in the analysis. The fluorine abundances
obtained for the M 4 red giants are found to be anti-correlated with those of
Na, following the typical pattern of abundance variations seen in globular
clusters between distinct stellar populations. In M 4, as the Na abundance
increases by +0.4 dex, the F abundance decreases by -0.2 dex. A
comparison with abundance predictions from two sets of stellar evolution models
finds that the models predict somewhat less F depletion (-0.1 dex) for
the same increase of +0.4 dex in Na
Fragmentation Increases Impact of Wind Disturbance on Forest Structure and Carbon Stocks in a Western Amazonian Landscape
Tropical second-growth forests could help mitigate climate change, but the degree to which their carbon potential is achieved will depend on exposure to disturbance. Wind disturbance is common in tropical forests, shaping structure, composition, and function, and influencing successional trajectories. However, little is known about the impacts of extreme winds in fragmented landscapes, though second-growth forests are often located in mosaics of forest, pasture, cropland, and other land cover types. Though indirect evidence suggests that fragmentation increases risk of wind damage, few studies have found such impacts following severe storms. In this study, we ask whether fragmentation and forest type (old vs. second growth) were associated with variation in wind damage after a severe convective storm in a fragmented production landscape in western Amazonia. We applied linear spectral unmixing to Landsat 8 imagery from before and after the storm, and combined it with field observations of damage to map wind effects on forest structure and biomass (Figure 4, 5). We also used Landsat 8 imagery to map land cover with the goals of identifying old- and second-growth forest and characterizing fragmentation. We used these data to assess variation in wind disturbance across 95,596 hectares of forest, distributed over 6,110 patches. We find that fragmentation is significantly associated with wind damage, with damage severity higher at forest edges and in edgier, more isolated patches (Figure 7). Damage was more severe in old-growth than in second-growth forests, but this effect was weaker than that of fragmentation (Figure 8). These results illustrate the importance of considering spatial configuration and landscape context in planning tropical forest restoration and predicting carbon sequestration in second-growth forests. Future research should address the mechanisms behind these results, to minimize wind damage risk in second-growth forests so their carbon potential can be maximally achieved
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