2,321 research outputs found
EMPLOYER SIZE, HUMAN CAPITAL, AND RURAL WAGES: IMPLICATIONS FOR SOUTHERN RURAL DEVELOPMENT
A recent trend in rural development policy emphasizes small business development in place of industrial recruitment. To analyze some of the likely effects of expanding the proportion of small firms in local economies, an empirical wage rate model incorporating employer size was developed, and parameters were estimated using household date from rural Putnam County, Georgia. The estimates indicated that large employers offered higher wages than small employers and that the wage premium they offered was greater for blacks than for whites. These results support Thomas Till's argument that southern rural counties with relatively large black populations should not abandon efforts to attract large employers. Other factors associated with higher wages included level of education, previous labor force experience, and employment in certain occupations and industries.Community/Rural/Urban Development, Labor and Human Capital,
Valsartan combination therapy in the management of hypertension â patient perspectives and clinical utility
The morbidity and mortality benefits of lowering blood pressure (BP) in hypertensive patients are well established, with most individuals requiring multiple agents to achieve BP control. Considering the important role of the renin-angiotensin-aldosterone system (RAAS) in the pathophysiology of hypertension, a key component of combination therapy should include a RAAS inhibitor. Angiotensin receptor blockers (ARBs) lower BP, reduce cardiovascular risk, provide organ protection, and are among the best tolerated class of antihypertensive therapy. In this article, we discuss two ARB combinations (valsartan/hydrochlorothiazide [HCTZ] and amlodipine/valsartan), both of which are indicated for the treatment of hypertension in patients not adequately controlled on monotherapy and as initial therapy in patients likely to need multiple drugs to achieve BP goals. Randomized, double-blind studies that have assessed the antihypertensive efficacy and safety of these combinations in the first-line treatment of hypertensive patients are reviewed. Both valsartan/HCTZ and amlodipine/valsartan effectively lower BP and are well tolerated in a broad range of patients with hypertension, including difficult-to-treat populations such as those with severe BP elevations, prediabetes and diabetes, patients with the cardiometabolic syndrome, and individuals who are obese, elderly, or black. Also discussed herein are patient-focused perspectives related to the use of valsartan/HCTZ and amlodipine/valsartan, and the rationale for use of single-pill combinations as one approach to enhance patient compliance with antihypertensive therapy
Tertiary-Treated Municipal Wastewater is a Significant Point Source of Antibiotic Resistance Genes Into Duluth-Superior Harbor
In this study, the impact of tertiary-treated municipal wastewater on the quantity of several antibiotic resistance determinants in Duluth-Superior Harbor was investigated by collecting surface water and sediment samples from 13 locations in Duluth-Superior Harbor, the St. Louis River, and Lake Superior. Quantitative PCR (qPCR) was used to target three different genes encoding resistance to tetracycline (tet(A), tet(X), and tet(W)), the gene encoding the integrase of class 1 integrons (intI1), and total bacterial abundance (16S rRNA genes) as well as total and human fecal contamination levels (16S rRNA genes specific to the genus Bacteroides). The quantities of tet(A), tet(X), tet(W), intI1, total Bacteroides, and human-specific Bacteroides were typically 20-fold higher in the tertiary-treated wastewater than in nearby surface water samples. In contrast, the quantities of these genes in the St. Louis River and Lake Superior were typically below detection. Analysis of sequences of tet(W) gene fragments from four different samples collected throughout the study site supported the conclusion that tertiary-treated municipal wastewater is a point source of resistance genes into Duluth-Superior Harbor. This study demonstrates that the discharge of exceptionally treated municipal wastewater can have a statistically significant effect on the quantities of antibiotic resistance genes in otherwise pristine surface waters
An adjusted and time-saving method to measure collateral ventilation with Chartis
INTRODUCTION: Bronchoscopic lung volume reduction with endobronchial valves is an important treatment option in selected patients with severe emphysema and absence of collateral ventilation in the treatment target lobe. The Chartis system provides an important physiological assessment of the presence or absence of collateral ventilation. We aimed to evaluate a new feature and determine whether low flow during a Chartis measurement is predictive for the absence of collateral ventilation, and whether this allows for a procedure to be shortened by earlier terminating the Chartis measurement. This is measured with the âvolume trend for the previous 20â
sâ (VT20). METHODS: We retrospectively evaluated 249 Chartis assessments of patients scheduled for bronchoscopic lung volume reduction procedures. The VT20 was calculated, and several thresholds were compared between patients with collateral ventilation (CV positive) and without collateral ventilation (CV negative). RESULTS: 100% of the CV negative patients reached a threshold of VT20 â€6â
mL, whereas all CV positive patients reached a VT20 â„7â
mL. The median âtime savedâ between VT20=6â
mL and end of assessment was 60â
s (range 5â354â
s). CONCLUSION: The threshold of VT20 â€6â
mL is a reliable method to exclude the presence of collateral ventilation when air flow rates are low and can therefore reduce bronchoscopic lung volume procedure times
X-ray spectral study of the hot gas in three Clusters of Galaxies
We study the physical properties of three clusters of galaxies, selected from
a BeppoSAX Wide Field Camera (WFC) survey. These sources are identified as 1RXS
J153934.7-833535, 1RXS J160147.6-754507, and 1RXS J081232.3-571423 in the ROSAT
All-Sky Survey catalogue. We obtained XMM-Newton follow-up observations for
these three clusters. We fit single and multi-temperature models to spectra
obtained from the EPIC-pn camera to determine the temperature, the chemical
composition of the gas and their radial distribution. Since two observations
are contaminated by a high soft-proton background, we develop a new method to
estimate the effect of this background on the data. For the first time, we
present the temperature and iron abundance of two of these three clusters. The
iron abundance of 1RXS J153934.7-33535 decreases with radius. The fits to the
XMM-Newton and Chandra data show that the radial temperature profile within 3'
towards the centre either flattens or lowers. A Chandra image of the source
suggests the presence of X-ray cavities. The gas properties in 1RXS
J160147.6-754507 are consistent with a flat radial distribution of iron and
temperature within 2' from the centre. 1RXS J081232.3-571423 is a relatively
cool cluster with a temperature of about 3 keV. The radial temperature and iron
profiles suggest that 1RXS J153934.7-833535 is a cool core cluster. The Chandra
image shows substructure which points toward AGN feedback in the core. The flat
radial profiles of the temperature and iron abundance in 1RXS J160147.6-754507
are similar to the profiles of non-cool-core clusters.Comment: Accepted for publication in A&A, 8 pages, 8 figures; corrected typos,
added data points on which fig 1 and 2 are based as comment to source file
Simulation of the Zero Temperature Behavior of a 3-Dimensional Elastic Medium
We have performed numerical simulation of a 3-dimensional elastic medium,
with scalar displacements, subject to quenched disorder. We applied an
efficient combinatorial optimization algorithm to generate exact ground states
for an interface representation. Our results indicate that this Bragg glass is
characterized by power law divergences in the structure factor . We have found numerically consistent values of the coefficient for
two lattice discretizations of the medium, supporting universality for in
the isotropic systems considered here. We also examine the response of the
ground state to the change in boundary conditions that corresponds to
introducing a single dislocation loop encircling the system. Our results
indicate that the domain walls formed by this change are highly convoluted,
with a fractal dimension . We also discuss the implications of the
domain wall energetics for the stability of the Bragg glass phase. As in other
disordered systems, perturbations of relative strength introduce a new
length scale beyond which the perturbed ground
state becomes uncorrelated with the reference (unperturbed) ground state. We
have performed scaling analysis of the response of the ground state to the
perturbations and obtain . This value is consistent with the
scaling relation , where characterizes the
scaling of the energy fluctuations of low energy excitations.Comment: 20 pages, 13 figure
The Interaction of 3C401 with the Surrounding Intracluster Medium
We present an observation of the radio-galaxy 3C401 and the surrounding
intracluster medium (ICM) of its host galaxy cluster by the Chandra X-ray
Observatory. This luminous radio-galaxy is notable in that it has
characteristics intermediate between the FRI and FRII morphologies. We clearly
detect point-like emission coincident with the radio-core of 3C401, although
the spatial resolution of even Chandra is only 2kpc at the distance of 3C401
(z=0.201) and so the possibility remains that this is a dense (and rapidly
cooling) thermal gaseous core in the center of the ICM atmosphere. Strong
departures from spherical symmetry in the central 10-20kpc of the ICM clearly
suggest interaction between the ICM and the radio-lobes of 3C401. A central
X-ray bar probably results from the evacuation of two ICM cavities by the
expanding radio lobes. Beyond these central regions, the cluster possesses a
flatter profile than many clusters of comparable mass suggesting the importance
of ICM heating and entropy injection by 3C401. We detect an interesting
cross-like structure in the ICM on 100kpc scales. We speculate that this could
be a radio-galaxy induced disturbance corresponding to a time when 3C401 was
substantially more powerful. A particularly exciting possibility is that this
cross-like structure corresponds to a large scale global g-mode oscillation
excited by a past outburst of 3C401.Comment: 7 pages, 5 postscript figures. Accepted for publication in MNRA
Spiral-like structure in nearby clusters of galaxies
X-ray data analysis have found that fairly complex structures at cluster
centres are more common than expected. Many of these structures have similar
morphologies, which exhibit spiral-like substructure. It is not yet well known
how these structures formed or are maintained. Understanding the origin of
these spiral-like features at the centre of some clusters is the major
motivation behind this work. We analyse deep \textit{Chandra} observations of
15 nearby galaxy clusters (0.01 0.06), and use X-ray temperature and
substructure maps to detect small features at the cores of the clusters. We
detect spiral-like features at the centre of 7 clusters: A85, A426, A496, Hydra
A cluster, Centaurus, Ophiuchus, and A4059. These patterns are similar to those
found in numerical hydrodynamic simulations of cluster mergers with non-zero
impact parameter. In some clusters of our sample, a strong radio source also
occupies the inner region of the cluster, which indicates a possible connection
between the two. Our investigation implies that these spiral-like structures
may be caused by off-axis minor mergers. Since these features occur in regions
of high density, they may confine radio emission from the central galaxy
producing, in some cases, unusual radio morphology.Comment: 14 pages, 3 figures, accepted for publication in A&A (Nov 17, 2009
Magnetic power spectra from Faraday rotation maps - REALMAF and its use on Hydra A
We develop a novel maximum-a-posteriori method to measure magnetic power
spectra from Faraday rotation data and implement it in the REALMAF code. A
sophisticated model for the magnetic autocorrelation in real space permits us
to alleviate previously required simplifying assumptions in the processing. We
also introduce a way to treat the divergence relation of the magnetic field
with a multiplicative factor in Fourier space, with which we can model the
magnetic autocorrelation as a spherically symmetric function. Applied to the
dataset of Hydra A north, we find a power law power spectrum on spatial scales
between 0.3 kpc and 8 kpc, with no visible turnover at large scales within this
range and a spectral index consistent with a Kolmogorov-like power law regime.
The magnetic field strength profile seems to follow the electron density
profile with an index alpha=1. A variation of alpha from 0.5 to 1.5 would lead
to a spectral index between 1.55 and 2.05. The extrapolated magnetic field
strength in the cluster centre highly depends on the assumed projection angle
of the jet. For an angle of 45 degree we derive extrapolated 36 muG in the
centre and directly probed 16 muG at 50 kpc radius.Comment: 13 pages, 13 figures, version accepted by A&A with restructured
introduction and language improvement
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