799 research outputs found

    The Effect Of Malintent On Visual Attention

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    Malintent is a relatively unexplored phenomenon, despite the practical and theoretical interest in its detection. The four studies presented here, informed by the Guilty Knowledge Test and Guided Search model of visual attention, illustrate how eye tracking can (and cannot) be utilized to detect malicious intent. Malintent, induced in two different mock crime paradigms (murder; theft), boosted the frequency and duration of fixations that fell upon objects relevant to their task. The size of the malintent effect ranged from moderate (fixation duration) to large (fixation frequency). The increased visual attention given to task-relevant objects was not unique to malintent; benign intent individuals, given the same task to perform without the transgressive framing, showed similar gaze patterns when they were unaware of the eye-tracking equipment. When made aware that their gaze was being tracked, those with malintent successfully avoided looking at the task-relevant object, while those with benign intent looked at it more often. The large moderating effect of eye-tracking awareness on the malintent effect poses both a challenge and an opportunity to the successful detection of malintent

    An evaluation of the vaccine-vector potential of thymidine kinase-disrupted recombinants of lumpy skin disease virus (South African vaccine)

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    Please read the abstract in the section 00front of this documentThesis (PhD (Genetics))--University of Pretoria, 2007.Geneticsunrestricte

    Potential link of single nucleotide polymorphisms (SNPs) to virulence of vaccine‐associated field strains of lumpy skin disease virus in South Africa

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    South Africa is endemic for lumpy skin disease and is therefore reliant on various live attenuated vaccines for the control and prevention of the disease. In recent years, wide‐spread outbreaks of vaccine‐like strains of lumpy skin disease virus (LSDV) were reported internationally, leading to an increase in the generation of full genome sequences from field isolates. In this study, the complete genomes of six LSDVs submitted during active outbreaks in the 1990’s in South Africa were generated. Based on phylogenetic analysis, the six viruses clustered with vaccine strains in LSDV Subgroup 1.1 and are subsequently referred to as vaccine‐associated. The genetic differences between the phenotypically distinct vaccine and vaccine‐associated strains were 67 single nucleotides polymorphisms (SNPs). This study characterised the location and possible importance of each of these SNPs in their role during virulence and host specificity

    Detection and genome sequencing of lumpy skin disease viruses in wildlife game species in South Africa

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    DATA AVAILABILITY STATEMENT : Sequences of assembled and annotated genomes are available at GenBank under the accessions: OR644282 to OR644284.Lumpy skin disease virus (LSDV) has recently undergone rapid spread, now being reported from more than 80 countries, affecting predominantly cattle and to a lesser extent, water buffalo. This poxvirus was previously considered to be highly host-range restricted. However, there is an increasing number of published reports on the detection of the virus from different game animal species. The virus has not only been shown to infect a wide range of game species under experimental conditions, but has also been naturally detected in oryx, giraffe, camels and gazelle. In addition, clinical lumpy skin disease has previously been described in springbok (Antidorcas marsupialis), an African antelope species, in South Africa. This report describes the characterization of lumpy skin disease virus belonging to cluster 1.2, from field samples from springbok, impala (Aepyceros melampus) and a giraffe (Giraffa camelopardalis) in South Africa using PCR, Sanger and whole genome sequencing. Most of these samples were submitted from wild animals in nature reserves or game parks, indicating that the disease is not restricted to captive-bred animals on game farms or zoological gardens. The potential role of wildlife species in the transmission and maintenance of LSDV is further discussed and requires continuing investigation, as the virus and disease may pose a serious threat to endangered species.The Department of Science and Technology (DST) and the Department of Agriculture Land Reform and Rural Development (DALRRD).https://www.mdpi.com/journal/viruseshj2024BiochemistryGeneticsMicrobiology and Plant PathologyVeterinary Tropical DiseasesSDG-03:Good heatlh and well-bein

    Lumpy skin disease : history, current understanding and research gaps in the context of recent geographic expansion

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    Lumpy skin disease is recognized as a transboundary and emerging disease of cattle, buffaloes and other wild ruminants. Being initially restricted to Africa, and since 1989 the Middle East, the unprecedented recent spread across Eurasia demonstrates how underestimated and neglected this disease is. The initial identification of the causative agent of LSD as a poxvirus called LSD virus, was well as findings on LSDV transmission and epidemiology were pioneered at Onderstepoort, South Africa, from as early as the 1940s by researchers such as Weiss, Haig and Alexander. As more data emerges from an ever-increasing number of epidemiological studies, previously emphasized research gaps are being revisited and discussed. The currently available knowledge is in agreement with the previously described South African research experience that LSDV transmission can occur by multiple routes, including indirect contact, shared water sources and arthropods. The virus population is prone to molecular evolution, generating novel phylogenetically distinct variants resulting from a diverse range of selective pressures, including recombination between field and homologous vaccine strains in cell culture that produce virulent recombinants which pose diagnostic challenges. Host restriction is not limited to livestock, with certain wild ruminants being susceptible, with unknown consequences for the epidemiology of the disease.The Ministry of Education and Science of Russia.http://www.frontiersin.org/Microbiologyam2024Veterinary Tropical DiseasesSDG-03:Good heatlh and well-beingSDG-15:Life on lan

    Wavefront sensing and control in space-based coronagraph instruments using Zernike’s phase-contrast method

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    Future space telescopes with coronagraph instruments will use a wavefront sensor (WFS) to measure and correct for phase errors and stabilize the stellar intensity in high-contrast images. The HabEx and LUVOIR mission concepts baseline a Zernike wavefront sensor (ZWFS), which uses Zernike’s phase contrast method to convert phase in the pupil into intensity at the WFS detector. In preparation for these potential future missions, we experimentally demonstrate a ZWFS in a coronagraph instrument on the Decadal Survey Testbed in the High Contrast Imaging Testbed facility at NASA’s Jet Propulsion Laboratory. We validate that the ZWFS can measure low- and mid-spatial frequency aberrations up to the control limit of the deformable mirror (DM), with surface height sensitivity as small as 1 pm, using a configuration similar to the HabEx and LUVOIR concepts. Furthermore, we demonstrate closed-loop control, resolving an individual DM actuator, with residuals consistent with theoretical models. In addition, we predict the expected performance of a ZWFS on future space telescopes using natural starlight from a variety of spectral types. The most challenging scenarios require ∼1  h of integration time to achieve picometer sensitivity. This timescale may be drastically reduced by using internal or external laser sources for sensing purposes. The experimental results and theoretical predictions presented here advance the WFS technology in the context of the next generation of space telescopes with coronagraph instruments
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