4,723 research outputs found
The problem of negative induced polarization anomalies
Equivalent circuit response and polarized sphere model to explain negative induced polarization anomalie
Grizzly bear habitat analysis. Section 2: Evaluation of grizzly bear food plants, food categories and habitat
There are no author-identified significant results in this report
Comparison of pre-emptive and reactive strategies to control an incursion of bluetongue virus serotype 1 to Great Britain by vaccination.
Bluetongue (BT) is a disease of ruminants caused by bluetongue virus (BTV), which is spread between its hosts by Culicoides midges. Vaccination is the most effective way to protect susceptible animals against BTV and was used reactively to control the recent northern European outbreak. To assess the consequences of using vaccination pre-emptively we used a stochastic, spatially explicit model to compare reactive and pre-emptive vaccination strategies against an incursion of BTV serotype 1 (BTV-1) into Great Britain. Both pre-emptive and reactive vaccination significantly reduced the number of affected farms and limited host morbidity and mortality. In addition, vaccinating prior to the introduction of disease reduced the probability of an outbreak occurring. Of the strategies simulated, widespread reactive vaccination resulted in the lowest levels of morbidity. The predicted effects of vaccination were found to be sensitive to vaccine efficacy but not to the choice of transmission kernel
Vaccinia virus immune evasion: mechanisms, virulence and immunogenicity
Virus infection of mammalian cells is sensed by pattern recognition receptors and leads to an innate immune response that restricts virus replication and induces adaptive immunity. In response, viruses have evolved many countermeasures that enable them to replicate and be transmitted to new hosts, despite the host innate immune response. Poxviruses, such as vaccinia virus (VACV), have large DNA genomes and encode many proteins that are dedicated to host immune evasion. Some of these proteins are secreted from the infected cell, where they bind and neutralize complement factors, interferons, cytokines and chemokines. Other VACV proteins function inside cells to inhibit apoptosis or signalling pathways that lead to the production of interferons and pro-inflammatory cytokines and chemokines. In this review, these VACV immunomodulatory proteins are described and the potential to create more immunogenic VACV strains by manipulation of the gene encoding these proteins is discussed
Modulation of linguistic prediction by TDCS of the right lateral cerebellum
AbstractIt has been postulated recently that the cerebellum contributes the same prediction and learning functions to linguistic processing as it does towards motor control. For example, repetitive TMS over posterior-lateral cerebellum caused a significant loss in predictive language processing, as assessed by the latency of saccades to target items of spoken sentences, using the Visual World task. We aimed to assess the polarity-specific effects of cerebellar TDCS, hypothesising that cathodal TDCS should impair linguistic prediction, and anodal TDCS facilitate it. Our design also tested whether TDCS modulated associative learning in this task. A between groups (sham, anodal, cathodal) design was used, with concurrent stimulation during performance of a manual variation of the Visual World paradigm, and with assessment of latency reduction over repeated presentations of the spoken sentences. Mixed model ANOVA was used to analyse change in response latency. Cathodal TDCS decreased participants’ response time advantage for the predictable sentence items without change for non-predictable items, consistent with the previous TMS results. Furthermore, anodal stimulation enhanced the response time advantage for the predictable items, again without change in latencies for non-predictive items. We found a clear practice-based effect over 4 blocks. However, this difference was not significantly modulated by either anodal or cathodal stimulation. Our results therefore support the hypothesis that cerebellum contributes to predictive language processing, mirroring its predictive role in motor control, but we do not yet have evidence that the learning process was affected by cerebellar TDCS
Negative and positive masked-priming – implications for motor inhibition
Masked stimuli can prime responses to subsequent target stimuli, causing response
benefits when the prime is similar to the target. However, one masked-prime
paradigm has produced counter-intuitive negative compatibility
effects (NCE), such that performance costs occur when prime and target are
similar. This NCE has been interpreted as an index of an automatic
self-inhibition mechanism that suppresses the partial motor activation caused by
the prime. However, several alternative explanations for the NCE have been
proposed and supported by new evidence. As a framework for discussion, I divide
the original theory into five potentially separable issues and briefly examine
each with regard to alternative theories and current evidence. These issues are:
1) whether the NCE is caused by motor inhibition or perceptual interactions; 2)
whether inhibition is self-triggered or stimulus-triggered; 3) whether prime
visibility plays a causal role; 4) whether there is a threshold for triggering
inhibition; 5) whether inhibition is automatic. Lastly, I briefly consider why
NCEs have not been reported in other priming paradigms, and what the neural
substrate for any automatic motor inhibition might be
Measuring random force noise for LISA aboard the LISA Pathfinder mission
The LTP (LISA Testflight Package), to be flown aboard the ESA / NASA LISA
Pathfinder mission, aims to demonstrate drag-free control for LISA test masses
with acceleration noise below 30 fm/s^2/Hz^1/2 from 1-30 mHz. This paper
describes the LTP measurement of random, position independent forces acting on
the test masses. In addition to putting an overall upper limit for all source
of random force noise, LTP will measure the conversion of several key
disturbances into acceleration noise and thus allow a more detailed
characterization of the drag-free performance to be expected for LISA.Comment: 7 pages, 3 figures. To be published in Classical and Quantum Gravity
with the proceedings of the 2003 Amaldi Meetin
Characterization of disturbance sources for LISA: torsion pendulum results
A torsion pendulum allows ground-based investigation of the purity of
free-fall for the LISA test masses inside their capacitive position sensor.
This paper presents recent improvements in our torsion pendulum facility that
have both increased the pendulum sensitivity and allowed detailed
characterization of several important sources of acceleration noise for the
LISA test masses. We discuss here an improved upper limit on random force noise
originating in the sensor. Additionally, we present new measurement techniques
and preliminary results for characterizing the forces caused by the sensor's
residual electrostatic fields, dielectric losses, residual spring-like
coupling, and temperature gradients.Comment: 11 pages, 8 figures, accepted for publication Classical and Quantum
Gravit
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