2,448 research outputs found
Spatial heterogeneity of habitat suitability for Rift Valley fever occurrence in Tanzania: an ecological niche modelling approach
Despite the long history of Rift Valley fever (RVF) in Tanzania, extent of its suitable habitat in the country remains unclear. In this study we investigated potential effects of temperature, precipitation, elevation, soil type, livestock density, rainfall pattern, proximity to wild animals, protected areas and forest on the habitat suitability for RVF occurrence in Tanzania. Presence-only records of 193 RVF outbreak locations from 1930 to 2007 together with potential predictor variables were used to model and map the suitable habitats for RVF occurrence using ecological niche modelling. Ground-truthing of the model outputs was conducted by comparing the levels of RVF virus specific antibodies in cattle, sheep and goats sampled from locations in Tanzania that presented different predicted habitat suitability values. Habitat suitability values for RVF occurrence were higher in the northern and central-eastern regions of Tanzania than the rest of the regions in the country. Soil type and precipitation of the wettest quarter contributed equally to habitat suitability (32.4% each), followed by livestock density (25.9%) and rainfall pattern (9.3%). Ground-truthing of model outputs revealed that the odds of an animal being seropositive for RVFV when sampled from areas predicted to be most suitable for RVF occurrence were twice the odds of an animal sampled from areas least suitable for RVF occurrence (95% CI: 1.43, 2.76, p < 0.001). The regions in the northern and central-eastern Tanzania were more suitable for RVF occurrence than the rest of the regions in the country. The modelled suitable habitat is characterised by impermeable soils, moderate precipitation in the wettest quarter, high livestock density and a bimodal rainfall pattern. The findings of this study should provide guidance for the design of appropriate RVF surveillance, prevention and control strategies which target areas with these characteristics
RELICS: The Reionization Lensing Cluster Survey and the Brightest High-z Galaxies
Massive foreground galaxy clusters magnify and distort the light of objects behind them, permitting a view into both the extremely distant and intrinsically faint galaxy populations. We present here the z ~ 6-8 candidate high-redshift galaxies from the Reionization Lensing Cluster Survey (RELICS), a Hubble and Spitzer Space Telescope survey of 41 massive galaxy clusters spanning an area of ≈200 arcmin². These clusters were selected to be excellent lenses, and we find similar high-redshift sample sizes and magnitude distributions as the Cluster Lensing And Supernova survey with Hubble (CLASH). We discover 257, 57, and eight candidate galaxies at z ~ 6, 7, and 8 respectively, (322 in total). The observed (lensed) magnitudes of the z ~ 6 candidates are as bright as AB mag ~23, making them among the brightest known at these redshifts, comparable with discoveries from much wider, blank-field surveys. RELICS demonstrates the efficiency of using strong gravitational lenses to produce high-redshift samples in the epoch of reionization. These brightly observed galaxies are excellent targets for follow-up study with current and future observatories, including the James Webb Space Telescope
Quantum nondemolition measurement of mechanical motion quanta
The fields of opto- and electromechanics have facilitated numerous advances
in the areas of precision measurement and sensing, ultimately driving the
studies of mechanical systems into the quantum regime. To date, however, the
quantization of the mechanical motion and the associated quantum jumps between
phonon states remains elusive. For optomechanical systems, the coupling to the
environment was shown to preclude the detection of the mechanical mode
occupation, unless strong single photon optomechanical coupling is achieved.
Here, we propose and analyse an electromechanical setup, which allows to
overcome this limitation and resolve the energy levels of a mechanical
oscillator. We find that the heating of the membrane, caused by the interaction
with the environment and unwanted couplings, can be suppressed for carefully
designed electromechanical systems. The results suggest that phonon number
measurement is within reach for modern electromechanical setups.Comment: 8 pages, 5 figures plus 24 pages, 11 figures supplemental materia
Enrichment of antioxidant capacity and vitamin E in pita made from barley
This study aimed to enhance total antioxidant and vitamin E content of pita bread, by replacing 50% of the standard baker's flour with flours milled from covered (WI2585 and Harrington) or hulless (Finniss) barley genotypes, previously shown to have high antioxidant and vitamin E levels at harvest. Pita breads were made from either 100% baker's flour (control) or 50% malt flour, whole-grain flour, or flour from barley grains pearled at 10%, 15%, and 20% grain weight. Antioxidant capacity and vitamin E content of flours and pitas were determined by their ability to scavenge 2,2-diphenyl-1-picrylhydrazyl radicals and high performance liquid chromatography, respectively. The physical and sensory properties of the pitas were also assessed. All pitas made from either whole grain or pearled barley flour had a higher antioxidant capacity and most also had higher vitamin E content than standard pita. The antioxidant and vitamin E levels were reduced in pearled compared to whole grains, however the extent of that reduction varied among genotypes. The greatest antioxidant and vitamin E levels were found in pita made from malt flour or Finniss whole grain flour. Furthermore, sensory analysis suggested these pitas were acceptable to consumers and retained similar physical and sensory properties to those in the control pita.Thi Thu Dung Do, Beverly Muhlhausler, Amanda Box and Amanda J. Abl
Blood profile holds clues to role of infection in a premonitory state for idiopathic parkinsonism and of gastrointestinal infection in established disease
The two-stage neuroinflammatory process, containment and progression, proposed to underlie neurodegeneration may predicate on systemic inflammation arising from the gastrointestinal tract. Helicobacter infection has been described as one switch in the pathogenic-circuitry of idiopathic parkinsonism (IP): eradication modifies disease progression and marked deterioration accompanies eradication-failure. Moreover, serum Helicobacter-antibody-profile predicts presence, severity and progression of IP. Slow gastrointestinal-transit precedes IP-diagnosis and becomes increasingly-apparent after, predisposing to small-intestinal bacterial-overgrowth (SIBO). Although IP is well-described as a systemic illness with a long prodrome, there has been no comprehensive overview of the blood profile. Here, it is examined in relation to Helicobacter status and lactulose-hydrogen-breath-testing for SIBO
Effective theories of single field inflation when heavy fields matter
We compute the low energy effective field theory (EFT) expansion for
single-field inflationary models that descend from a parent theory containing
multiple other scalar fields. By assuming that all other degrees of freedom in
the parent theory are sufficiently massive relative to the inflaton, it is
possible to derive an EFT valid to arbitrary order in perturbations, provided
certain generalized adiabaticity conditions are respected. These conditions
permit a consistent low energy EFT description even when the inflaton deviates
off its adiabatic minimum along its slowly rolling trajectory. By generalizing
the formalism that identifies the adiabatic mode with the Goldstone boson of
this spontaneously broken time translational symmetry prior to the integration
of the heavy fields, we show that this invariance of the parent theory dictates
the entire non-perturbative structure of the descendent EFT. The couplings of
this theory can be written entirely in terms of the reduced speed of sound of
adiabatic perturbations. The resulting operator expansion is distinguishable
from that of other scenarios, such as standard single inflation or DBI
inflation. In particular, we re-derive how certain operators can become
transiently strongly coupled along the inflaton trajectory, consistent with
slow-roll and the validity of the EFT expansion, imprinting features in the
primordial power spectrum, and we deduce the relevant cubic operators that
imply distinct signatures in the primordial bispectrum which may soon be
constrained by observations.Comment: (v1) 25 pages, 1 figure; (v2) references added and typos corrected,
to appear in Journal of High Energy Physic
Expression profiling to predict outcome in breast cancer: the influence of sample selection
Gene expression profiling of tumors using DNA microarrays is a promising method for predicting prognosis and treatment response in cancer patients. It was recently reported that expression profiles of sporadic breast cancers could be used to predict disease recurrence better than currently available clinical and histopathological prognostic factors. Having observed an overlap in those data between the genes that predict outcome and those that predict estrogen receptor-α status, we examined their predictive power in an independent data set. We conclude that it may be important to define prognostic expression profiles separately for estrogen receptor-α-positive and estrogen receptor-α-negative tumors
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Mycolactone-dependent depletion of endothelial cell thrombomodulin is strongly associated with fibrin deposition in Buruli ulcer lesions
A well-known histopathological feature of diseased skin in Buruli ulcer (BU) is coagulative necrosis caused by the Mycobacterium ulcerans macrolide exotoxin mycolactone. Since the underlying mechanism is not known, we have investigated the effect of mycolactone on endothelial cells, focussing on the expression of surface anticoagulant molecules involved in the protein C anticoagulant pathway. Congenital deficiencies in this natural anticoagulant pathway are known to induce thrombotic complications such as purpura fulimans and spontaneous necrosis. Mycolactone profoundly decreased thrombomodulin (TM) expression on the surface of human dermal microvascular endothelial cells (HDMVEC) at doses as low as 2ng/ml and as early as 8hrs after exposure. TM activates protein C by altering thrombin's substrate specificity, and exposure of HDMVEC to mycolactone for 24 hours resulted in an almost complete loss of the cells' ability to produce activated protein C. Loss of TM was shown to be due to a previously described mechanism involving mycolactone-dependent blockade of Sec61 translocation that results in proteasome-dependent degradation of newly synthesised ER-transiting proteins. Indeed, depletion from cells determined by live-cell imaging of cells stably expressing a recombinant TM-GFP fusion protein occurred at the known turnover rate. In order to determine the relevance of these findings to BU disease, immunohistochemistry of punch biopsies from 40 BU lesions (31 ulcers, nine plaques) was performed. TM abundance was profoundly reduced in the subcutis of 78% of biopsies. Furthermore, it was confirmed that fibrin deposition is a common feature of BU lesions, particularly in the necrotic areas. These findings indicate that there is decreased ability to control thrombin generation in BU skin. Mycolactone's effects on normal endothelial cell function, including its ability to activate the protein C anticoagulant pathway are strongly associated with this. Fibrin-driven tisischemia could contribute to the development of the tissue necrosis seen in BU lesions
Skillful long-range prediction of European and North American winters
This is the final version. Available from AGU via the DOI in this recordUntil recently, long-range forecast systems showed only modest levels of skill in predicting surface winter climate around the Atlantic Basin and associated fluctuations in the North Atlantic Oscillation at seasonal lead times. Here we use a new forecast system to assess seasonal predictability of winter North Atlantic climate. We demonstrate that key aspects of European and North American winter climate and the surface North Atlantic Oscillation are highly predictable months ahead. We demonstrate high levels of prediction skill in retrospective forecasts of the surface North Atlantic Oscillation, winter storminess, near-surface temperature, and wind speed, all of which have high value for planning and adaptation to extreme winter conditions. Analysis of forecast ensembles suggests that while useful levels of seasonal forecast skill have now been achieved, key sources of predictability are still only partially represented and there is further untapped predictability. Key Points The winter NAO can be skilfully predicted months ahead The signal-to-noise ratio of the predictable signal is anomalously low Predictions of the risk of regional winter extremes are possibleThis work was supported by the Joint DECC/Defra Met Office Hadley Centre Climate Programme (GA01101), the UK Public Weather Service research program, and the European Union Framework 7 SPECS project. Leon Hermanson was funded as part of his Research Fellowship by Willis as part of Willis Research Network (WRN)
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