387 research outputs found
Mathematical Models for Estimating the Risk of vCJD Transmission
We present two different simple models for vCJD transmission by blood transfusion. Both models indicate that transfusions alone are unlikely to cause more than a few infections, unless the number of primary cases increases.
To improve our models, future work should pursue data collection, empirical estimation of the model parameters, and examination of the underlying assumptions of our frameworks.
Further improvements could also include examining susceptibility to vCJD infection by age group and iatrogenic infections introduced through surgical instruments. Regarding the latter, it may be worthwhile to conduct experiments to quantify the transmission of prions from an infected surgical instrument after repeated sterilization procedures
Localization from quantum interference in one-dimensional disordered potentials
We show that the tails of the asymptotic density distribution of a quantum
wave packet that localizes in the the presence of random or quasiperiodic
disorder can be described by the diagonal term of the projection over the
eingenstates of the disordered potential. This is equivalent of assuming a
phase randomization of the off-diagonal/interference terms. We demonstrate
these results through numerical calculations of the dynamics of ultracold atoms
in the one-dimensional speckle and quasiperiodic potentials used in the recent
experiments that lead to the observation of Anderson localization for matter
waves [Billy et al., Nature 453, 891 (2008); Roati et al., Nature 453, 895
(2008)]. For the quasiperiodic case, we also discuss the implications of using
continuos or discrete models.Comment: 5 pages, 3 figures; minor changes, references update
Nutrient composition of Algerian strawberry-tree fruits (Arbutus unedo L.)
Arbutus unedo L. (strawberry-tree fruit) is indigenous plant in North Africa with few published works about the composition of its fruits. For their valorization, morphological and chemical characterizations were carried out for two harvesting seasons of four different areas of Algeria. Materials and methods. Wild strawberry-tree fruits were collected in four different sites located in Tell Atlas, and two different seasons. Fruit size and shape, pH, titratable acidity, moisture, total available carbohydrate (TAC), soluble sugars, dietary fiber, protein, lipid, ash, fatty acids and mineral composition (K, Na, Ca, Mg, Fe, Cu, Mn, Zn, Ni and Cd) were determined. Results and discussion. Fruit contents (in g kg−1) varied between 637.3 ± 33.8 to 741.3 ±12.0, 126.8 ± 11.1 to 189.3 ± 4.1, 22.6 ± 2.2 to 35.5 ± 2.1, 5.1 ± 0.3 to 8.8 ± 0.5 for moisture, TAC, protein and lipid, respectively. For iron, fruit weight and polyunsaturated fatty acids (PUFA), the contents varied between 7.01 ± 0.15 to 17.24 ± 0.74 mg kg−1 of fruit, 4.91 ± 1.58 to 6.76 ± 2.04 g and 56.34 ± 1.37 to 68.18 ± 0.14% of lipid, respectively. Conclusion. This study provides original data about the morphological and chemical composition of strawberry-tree fruits from Algeria. The results show that the fruits can be essentially a potential source of dietary fiber, PUFA and iron.The authors are grateful to the Algerian Ministry of Higher Education and Scientific Research
for funding the study; to ALIMNOVA research group (UCMGR35/10A) for financial support
and to the Foundation for Science and Technology (FCT, Portugal) for financial support to
CIMO (Pest-OE/AGR/UI0690/2015) and L. Barros (SFRH/BPD/107855/2015)info:eu-repo/semantics/publishedVersio
H spectroscopy of the high-inclination black hole transient Swift J1357.2-0933 during quiescence
Swift J1357.2-0933 is a transient low-mass X-ray binary hosting a
stellar-mass black hole. The source exhibits optical dips and very broad
emission lines during both outburst and quiescence, which are thought to be the
result of a high orbital inclination. We present phase-resolved spectroscopy
obtained with the 10.4m Gran Telescopio Canarias (GTC). The spectra focus on
the spectral region during X-ray quiescence. The emission line is
exceptionally broad (full width at half maximum, FWHM > 4000 \AA), in agreement
with previous studies focused on . A two-Gaussian fit to the
prominent double-peaked profile reveals a periodic variability in the centroid
position of the line. We also produced a diagnostic diagram aimed at
constraining additional orbital parameters. Together, they allow us to
independently confirm the orbital period of the system using a new dataset
obtained five years after the previous outburst. However, our estimates for
both the systemic velocity and the radial velocity semi-amplitude of the black
hole reveal larger values than those found in previous studies. We argue that
this could be explained by the precession of the disc and the presence of a
hotspot. We found evidence of a narrow inner core in the double-peaked H
emission profile. We studied its evolution across the orbit, finding that it is
likely to result from the occultation of inner material by the outer rim bulge,
further supporting the high orbital inclination hypothesis.Comment: 6 pages, 4 figure
SIREs: searching for iron-responsive elements
The iron regulatory protein/iron-responsive element regulatory system plays a crucial role in the post-transcriptional regulation of gene expression and its disruption results in human disease. IREs are cis-acting regulatory motifs present in mRNAs that encode proteins involved in iron metabolism. They function as binding sites for two related trans-acting factors, namely the IRP-1 and -2. Among cis-acting RNA regulatory elements, the IRE is one of the best characterized. It is defined by a combination of RNA sequence and structure. However, currently available programs to predict IREs do not show a satisfactory level of sensitivity and fail to detect some of the functional IREs. Here, we report an improved software for the prediction of IREs implemented as a user-friendly web server tool. The SIREs web server uses a simple data input interface and provides structure analysis, predicted RNA folds, folding energy data and an overall quality flag based on properties of well characterized IREs. Results are reported in a tabular format and as a schematic visual representation that highlights important features of the IRE. The SIREs (Search for iron-responsive elements) web server is freely available on the web at http://ccbg.imppc.org/sires/index.htm
Spectroscopic classification of X-ray sources in the Galactic Bulge Survey
We present the classification of 26 optical counterparts to X-ray sources
discovered in the Galactic Bulge Survey. We use (time-resolved) photometric and
spectroscopic observations to classify the X-ray sources based on their
multi-wavelength properties. We find a variety of source classes, spanning
different phases of stellar/binary evolution. We classify CX21 as a quiescent
cataclysmic variable (CV) below the period gap, and CX118 as a high accretion
rate (nova-like) CV. CXB12 displays excess UV emission, and could contain a
compact object with a giant star companion, making it a candidate symbiotic
binary or quiescent low mass X-ray binary (although other scenarios cannot be
ruled out). CXB34 is a magnetic CV (polar) that shows photometric evidence for
a change in accretion state. The magnetic classification is based on the
detection of X-ray pulsations with a period of 81 2 min. CXB42 is
identified as a young stellar object, namely a weak-lined T Tauri star
exhibiting (to date unexplained) UX Ori-like photometric variability. The
optical spectrum of CXB43 contains two (resolved) unidentified double-peaked
emission lines. No known scenario, such as an AGN or symbiotic binary, can
easily explain its characteristics. We additionally classify 20 objects as
likely active stars based on optical spectroscopy, their X-ray to optical flux
ratios and photometric variability. In 4 cases we identify the sources as
binary stars.Comment: Accepted for publication in MNRA
Global and regional cortical thinning in first-episode psychosis patients: relationships with clinical and cognitive features
BackgroundThe thickness of the cortical mantle is a sensitive measure for identifying alterations in cortical structure. We aimed to explore whether first episode schizophrenia patients already show a significant cortical thinning and whether cortical thickness anomalies may significantly influence clinical and cognitive features.MethodWe investigated regional changes in cortical thickness in a large and heterogeneous sample of schizophrenia spectrum patients (n=142) at their first break of the illness and healthy controls (n=83). Magnetic resonance imaging brain scans (1.5 T) were obtained and images were analyzed by using BRAINS2. The contribution of sociodemographic, cognitive and clinical characterictics was investigated.ResultsPatients showed a significant total cortical thinning (F=17.55, d=−0.62, p0.53). No significant group × gender interactions were observed (all p’s>0.15). There were no significant associations between the clinical and pre-morbid variables and cortical thickness measurements (all r’s<0.12). A weak significant negative correlation between attention and total (r=−0.24, p=0.021) and parietal cortical thickness (r=−0.27, p=0.009) was found in patients (thicker cortex was associated with lower attention). Our data revealed a similar pattern of cortical thickness changes related to age in patients and controls.ConclusionsCortical thinning is independent of gender, age, age of onset and duration of the illness and does not seem to significantly influence clinical and functional symptomatology. These findings support a primary neuro-development disorder affecting the normal cerebral cortex development in schizophrenia
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