759 research outputs found
Molecular detection and phylogenetic analysis of Peste des petits ruminants virus circulating in small ruminants in eastern Amhara region, Ethiopia
Background: Peste des Petits Ruminants (PPR) is a severe, highly infectious and fatal viral disease of small ruminants. Four lineages of PPR virus have been identified globally based on sequence analysis of the nucleoprotein (N) and fusion (F) gene. The aim of this study was to isolate and genetically characterize recently circulating PPR virus in small ruminants in the eastern Amhara region in Ethiopia. A total of 28 anti-mortem samples (gum debris, nasal and ocular swab) were collected from clinically suspicious animals and examined for the presence of PPRV by a one-step RT-PCR assay. Samples positive with RT-PCR were subjected to isolation of the virus which were subsequently genetically characterized by sequencing of the nucleoprotein (N) gene and phylogenetic analysis of PPR virus (PPRV) strains. Results: Of the 28 clinical samples examined, 46.4% were positive with RT-PCR for viral nucleic acid. The PPRV was successfully isolated on CHS-20 cell line with the ovine signaling lymphocyte activation molecule (SLAM) receptor expressed on the cell surface and confirmed with RT-PCR and IFAT assay. The nucleotide sequence and phylogenetic analysis indicated that the PPRV obtained were clustered genetically with Lineage IV isolates of the virus. Conclusion: The successful isolation of the virus and molecular findings of this study confirmed active lineage IV PPRV infections among populations of sheep and goats in eastern Amhara, suggesting risks for potential spread of the disease to currently free areas. Thus, we recommend systematic vaccination to contain outbreaks in affected districts and geographically linked surrounding districts to which the disease could potentially spread due to different epidemiological linkages
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Data on eye movements in people with glaucoma and peers with normal vision.
Eye movements of glaucoma patients have been shown to differ from age-similar control groups when performing everyday tasks, such as reading (Burton et al., 2012; Smith et al., 2014) [1], [2], visual search (Smith et al., 2012) [3], face recognition (Glen et al., 2013) [4], driving, and viewing static images (Smith et al., 2012) [5]. Described here is the dataset from a recent publication in which we compared the eye-movements of 44 glaucoma patients and 32 age-similar controls, while they watched a series of short video clips taken from television programs (Crabb et al., 2018) [6]. Gaze was recorded at 1000 Hz using a remote eye-tracker. We also provide demographic information and results from a clinical examination of vision for each participant
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Does Glaucoma Alter Eye Movements When Viewing Images of Natural Scenes? A Between-Eye Study
Purpose: To investigate whether glaucoma produces measurable changes in eye movements.
Methods: Fifteen glaucoma patients with asymmetric vision loss (difference in mean deviation [MD] > 6 dB between eyes) were asked to monocularly view 120 images of natural scenes, presented sequentially on a computer monitor. Each image was viewed twice—once each with the better and worse eye. Patients' eye movements were recorded with an Eyelink 1000 eye-tracker. Eye-movement parameters were computed and compared within participants (better eye versus worse eye). These parameters included a novel measure: saccadic reversal rate (SRR), as well as more traditional metrics such as saccade amplitude, fixation counts, fixation duration, and spread of fixation locations (bivariate contour ellipse area [BCEA]). In addition, the associations of these parameters with clinical measures of vision were investigated.
Results: In the worse eye, saccade amplitude
(P=0.012;−13%) and BCEA (P=0.005;−16%) were smaller, while SRR was greater (P=0.018;+16%). There was a significant correlation between the intereye difference in BCEA, and differences in MD values (Spearman′s r=0.65;P=0.01), while differences in SRR were associated with differences in visual acuity (Spearman′s r=0.64;P=0.01
). Furthermore, between-eye differences in BCEA were a significant predictor of between-eye differences in MD: for every 1-dB difference in MD, BCEA reduced by 6.2% (95% confidence interval, 1.6%–10.3%).
Conclusions: Eye movements are altered by visual field loss, and these changes are related to changes in clinical measures. Eye movements recorded while passively viewing images could potentially be used as biomarkers for visual field damage
Epidemiological investigation of Peste des petits ruminants virus in small ruminants in Eastern Amhara, Ethiopia
International Fund for Agricultural Developmen
Work extremum principle: Structure and function of quantum heat engines
We consider a class of quantum heat engines consisting of two subsystems
interacting via a unitary transformation and coupled to two separate baths at
different temperatures . The purpose of the engine is to extract
work due to the temperature difference. Its dynamics is not restricted to the
near equilibrium regime. The engine structure is determined by maximizing the
extracted work under various constraints. When this maximization is carried out
at finite power, the engine dynamics is described by well-defined temperatures
and satisfies the local version of the second law. In addition, its efficiency
is bounded from below by the Curzon-Ahlborn value and from
above by the Carnot value . The latter is reached|at finite
power|for a macroscopic engine, while the former is achieved in the equilibrium
limit . When the work is maximized at a zero power, even a small
(few-level) engine extracts work right at the Carnot efficiency.Comment: 16 pages, 5 figure
Direct observation of active material concentration gradients and crystallinity breakdown in LiFePO4 electrodes during charge/discharge cycling of lithium batteries
The phase changes that occur during discharge of an electrode comprised of LiFePO4, carbon, and PTFE binder have been studied in lithium half cells by using X-ray diffraction measurements in reflection geometry. Differences in the state of charge between the front and the back of LiFePO4 electrodes have been visualized. By modifying the X-ray incident angle the depth of penetration of the X-ray beam into the electrode was altered, allowing for the examination of any concentration gradients that were present within the electrode. At high rates of discharge the electrode side facing the current collector underwent limited lithium insertion while the electrode as a whole underwent greater than 50% of discharge. This behavior is consistent with depletion at high rate of the lithium content of the electrolyte contained in the electrode pores. Increases in the diffraction peak widths indicated a breakdown of crystallinity within the active material during cycling even during the relatively short duration of these experiments, which can also be linked to cycling at high rate
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Monitoring drought in Ghana using TAMSAT-ALERT: A new decision support system
Many African people are reliant on agriculture as a means of survival and are particularly sensitive to variations in rainfall. There is therefore a clear need for usable risk assessment and decision support tools for the management of agricultural drought (soil moisture deficit). This article describes an application of TAMSAT-ALERT (Tropical Applications of Meteorology using SATellite data and ground-based observations AgriculturaL EaRly warning sysTem), a decision support tool which exploits the expected persistence of root zone soil moisture anomalies to provide early warnings of agricultural drought. The persistence of soil moisture anomalies in the deeper layers of the soil for weeks or months may be expected to lead to a degree of predictability of soil moisture deficit – even in the absence of skilful prediction of precipitation. At a given time, the probability of soil moisture deficit at some point in the future is related to the current soil moisture and the likelihood of insufficient rain in the ensuing period. Current soil moisture depends on the land surface properties (vegetation and soil texture) and the meteorological conditions over the previous days or months. The likelihood of sufficient rainfall within a particular time frame depends on the climatology, both of rainfall and of other meteorological variables that influence the water balance. The premise of this application of TAMSAT-ALERT is that after a certain date we can be confident of an ensuing drought because, even if it rains as much as it ever has before, the soil moisture will not recover to normal levels. In essence, the system addresses the question: Given the current state of the land surface and the historical climatology, what is the likelihood of agricultural drought
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Using eye movements to detect visual field loss: a pragmatic assessment using simulated scotoma.
Glaucoma is a leading cause of irreversible sight-loss and has been shown to affect natural eye-movements. These changes may provide a cheap and easy-to-obtain biomarker for improving disease detection. Here, we investigated whether these changes are large enough to be clinically useful. We used a gaze-contingent simulated visual field (VF) loss paradigm, in which participants experienced a variable magnitude of simulated VF loss based on longitudinal data from a real glaucoma patient (thereby controlling for other variables, such as age and general health). Fifty-five young participants with healthy vision were asked to view two short videos and three pictures, either with: (1) no VF loss, (2) moderate VF loss, or (3) advanced VF loss. Eye-movements were recorded using a remote eye tracker. Key eye-movement parameters were computed, including saccade amplitude, the spread of saccade endpoints (bivariate contour ellipse area), location of saccade landing positions, and similarity of fixations locations among participants (quantified using kernel density estimation). The simulated VF loss caused some statistically significant effects in the eye movement parameters. Yet, these effects were not capable of consistently identifying simulated VF loss, despite it being of a magnitude likely easily detectable by standard automated perimetry
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