9,817 research outputs found
Reconstructing the Dietary Signal of the Primate Taxon Cercopithecoides williamsi from the Plio-Pleistocene Caves of South Africa
The taxon known as Cercopithecoides williamsi has been reconstructed as a terrestrial primate folivore from its dental morphology and heavy dental microwear. It was recovered at a number of Plio-Pleistocene caves in South Africa, including Makapansgat, Sterkfontein Member 4, Sterkfontein West Pit and Bolt’s Farm. For the purposes of corroborating or contradicting previous dietary reconstructions, six specimens of Cercopithecoides williamsi were examined and compared with the extant primate taxa Papio ursinus (n = 5), Papio cynocephalus (n = 5) and Colobus polykomos (n = 5) to provide a frame of reference, using low-magnification stereomicroscopy in conjunction with an ocular reticle (0.04 mm x 0.04 mm) as a standard sampling strategy. Least Square Means derived from Analyses of Variance and Tukey’s post-hoc tests of significance detected significant signals in the dataset. Papio ursinus is significantly distinct from the other specimens in its low pit count and high scratch frequency, indicative of the consumption of grass blades and underground storage organs. Colobus polykomos is significantly distinct in its high number of pits and low scratch frequency, indicating folivory. Cercopithecoides williamsi lies between these two extremes by exhibiting moderate amounts of pits and relatively low numbers of scratches, which is more similar to Colobus polykomos, corroborating prior inferences of folivory in this taxon. The Sterkfontein West Pit specimen, SWP 495, however, is somewhat variant from the other Cercopithecoides williamsi individuals in its heavy scratch count, indicating a mixed diet, perhaps from a drier habitat at the terminal Pliocene or early Pleistocene
Shwartzman reaction after human renal homotransplantation.
In three human recipients, five renal homografts were destroyed within a few minutes to hours after their revascularization in the new host. The kidneys, removed one to 54 days later, had cortical necrosis. The major vessels were patent, but the arterioles and glomeruli were the site of fibrin deposition. There was little or no fixation of host immunoglobulins in the homografts. The findings were characteristic of a generalized Shwartzman reaction. Although the cause (or causes) of the Shwartzman reaction in our patients is not known, they may have been conditioned by the bacterial contamination and hemolysis that often attend hemodialysis, by immunosuppression and by the transplantation itself. Some of the patients have preformed lymphocytotoxic antibodies. Thus, certain patients may be predisposed. High-risk patients should be recognized and treated prophylactically with anticoagulants
A Deep XMM-Newton Survey of M33: Point Source Catalog, Source Detection and Characterization of Overlapping Fields
We have obtained a deep 8-field XMM-Newton mosaic of M33 covering the galaxy
out to the D isophote and beyond to a limiting 0.2--4.5 keV unabsorbed
flux of 510 erg cm s (L410
erg s at the distance of M33). These data allow complete coverage of the
galaxy with high sensitivity to soft sources such as diffuse hot gas and
supernova remnants. Here we describe the methods we used to identify and
characterize 1296 point sources in the 8 fields. We compare our resulting
source catalog to the literature, note variable sources, construct hardness
ratios, classify soft sources, analyze the source density profile, and measure
the X-ray luminosity function. As a result of the large effective area of
XMM-Newton below 1 keV, the survey contains many new soft X-ray sources. The
radial source density profile and X-ray luminosity function for the sources
suggests that only 15% of the 391 bright sources with
L3.610 erg s are likely to be associated with M33,
and more than a third of these are known supernova remnants. The log(N)--log(S)
distribution, when corrected for background contamination, is a relatively flat
power-law with a differential index of 1.5, which suggests many of the other
M33 sources may be high-mass X-ray binaries. Finally, we note the discovery of
an interesting new transient X-ray source, which we are unable to classify.Comment: 26 pages, 6 tables, 13 figures, accepted for publication in ApJ
A Soft X-ray Transient in the M31 Bulge
We have examined a probable soft X-ray transient source in the M31 bulge at
R.A.=0:42:41.814 +/- 0.08", Dec. = 41:16:35.86 +/- 0.07". On the three
occasions we observed the source, its spectrum was soft (kT_{in} ~1 keV). The
brightest detection of the source was 2004 July 17 with a 0.3-7 keV luminosity
of ~5 X 10^{37} erg/s. The only previous detection of the source was in 1979 by
the Einstein observatory. The multiple detections over 25 years suggest the
duty cycle of the source is in the range 0.02-0.06. Coordinated HST/ACS imaging
before, during, and after the outburst revealed no variable optical source
within the position errors of the X-ray source. The optical data place a firm
upper limit on the brightness of the counterpart of the X-ray outburst of
B>24.7, suggesting the binary has a period <5.2 days. The X-ray spectrum and
lack of bright stars at the source location indicate the source was a soft
transient event occurring in a low-mass X-ray binary, making this source a good
black hole candidate in M31.Comment: 18 pages, 4 tables, 3 figures, accepted for publication in Ap
The CH3SH molecule deposited on Cu(111) and deprotonation
We demonstrate for the first time that when a methanethiol adsorbed on the
regular Cu(111) surface, the dissociative structure is thermodynamically more
stable than the intact one. The computational results show that at low
temperature the methanethiol adsorbate prefers the atop site of the regular
Cu(111) surface. As the temperature is increased, the S-H bond is broken and
the methylthiolate favors the hollow sites. On the defected Cu(111) surface,
the dissociative configuration is still thermodynamically more stable than the
nondissociative one. The calculation indicates that the hydrogen initially
attached to the sulfur would like to form a bond with the copper surface rather
than desorb from it. Even though both copper and gold are the noble metal, the
stability of the methanethiol adsorption on the Cu(111) substrate is almost the
reverse of that on the Au(111).Comment: 13 pages, 7 figures, submitted to Phys. Rev.
Implications of Simultaneity in a Physical Damage Function
A modeler must often rely on highly simplified representations of complex physical systems when analyzing associated economic issues. Herein, we consider a management problem in which a bioeconomic system exhibits simultaneity in processes governing productivity and damage. In this case, it may benefit the producer to sacrifice productivity to reduce the costs associated with increased damage. We specify empirically a structural damage relationship that explains the biological process by which an invasive species damages a host and estimate the structural model and its reduced form with an exceptional dataset on infestation of olives by the olive fruit fly. We contrast the results of these models with the approach typically taken in the economic literature, which expresses damage as a function of pest density. The population-based approach introduces significantly greater bias into the individual grower\u27s choice of damage-control inputs than estimates based on the structural model
A cluster-randomised controlled trial of values-based training to promote autonomously held recovery values in mental health workers
The implementation and use of evidence-based practices is a key priority for recovery-oriented mental health service provision. Training and development programmes for employees continue to be a key method of knowledge and skill development, despite acknowledged difficulties with uptake and maintenance of behaviour change. Self-determination theory suggests that autonomy, or a sense that behaviour is self-generated, is a key motivator to sustained behaviour change, in this case practices in mental health services. This study examined the utility of values-focused staff intervention as a specific, reproducible method of autonomy support
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