Differential cytokine responses following Marek's disease virus infection in chicken genotypes differing in resistance to Marek's disease

The production of cytokine mRNAs, in addition to viral DNA, was quantified by real-time quantitative reverse transcription-PCR (RT-PCR) (cytokines) or PCR (virus) in splenocytes during the course of Marek's disease virus (MDV) infection in four inbred chicken lines: two resistant (lines 61 and N) and two susceptible (lines 72 and P). Virus loads were only different after 10 days postinfection (dpi), increasing in susceptible lines and decreasing in resistant lines. Gamma interferon (IFN-γ) mRNA was expressed by splenocytes from all infected birds between 3 and 10 dpi, associated with increasing MDV loads. For other cytokines, differences between lines were only seen for interleukin-6 (IL-6) and IL-18, with splenocytes from susceptible birds expressing high levels of both transcripts during the cytolytic phase of infection, whereas splenocytes from resistant birds expressed neither transcript. These results indicate that these two cytokines could play a crucial role in driving immune responses, which in resistant lines maintain MDV latency but in susceptible lines result in lymphomas

The peptide motif of the single dominantly expressed class I molecule of the chicken MHC can explain the response to a molecular defined vaccine of infectious bursal disease virus (IBDV)

In contrast to typical mammals, the chicken MHC (the BF-BL region of the B locus) has strong genetic associations with resistance and susceptibility to infectious pathogens as well as responses to vaccines. We have shown that the chicken MHC encodes a single dominantly expressed class I molecule whose peptide-binding motifs can determine resistance to viral pathogens, such as Rous sarcoma virus and Marek’s disease virus. In this report, we examine the response to a molecular defined vaccine, fp-IBD1, which consists of a fowlpox virus vector carrying the VP2 gene of infectious bursal disease virus (IBDV) fused with ?-galactosidase. We vaccinated parental lines and two backcross families with fp-IBD1, challenged with the virulent IBDV strain F52/70, and measured damage to the bursa. We found that the MHC haplotype B15 from line 15I confers no protection, whereas B2 from line 61 and B12 from line C determine protection, although another locus from line 61 was also important. Using our peptide motifs, we found that many more peptides from VP2 were predicted to bind to the dominantly expressed class I molecule BF2*1201 than BF2*1501. Moreover, most of the peptides predicted to bind BF2*1201 did in fact bind, while none bound BF2*1501. Using peptide vaccination, we identified one B12 peptide that conferred protection to challenge, as assessed by bursal damage and viremia. Thus, we show the strong genetic association of the chicken MHC to a T cell vaccine can be explained by peptide presentation by the single dominantly expressed class I molecule

Post-Impact Thermal Evolution of Porous Planetesimals

Impacts between planetesimals have largely been ruled out as a heat source in the early Solar System, by calculations that show them to be an inefficient heat source and unlikely to cause global heating. However, the long-term, localized thermal effects of impacts on planetesimals have never been fully quantified. Here, we simulate a range of impact scenarios between planetesimals to determine the post-impact thermal histories of the parent bodies, and hence the importance of impact heating in the thermal evolution of planetesimals. We find on a local scale that heating material to petrologic type 6 is achievable for a range of impact velocities and initial porosities, and impact melting is possible in porous material at a velocity of > 4 km/s. Burial of heated impactor material beneath the impact crater is common, insulating that material and allowing the parent body to retain the heat for extended periods (~ millions of years). Cooling rates at 773 K are typically 1 - 1000 K/Ma, matching a wide range of measurements of metallographic cooling rates from chondritic materials. While the heating presented here is localized to the impact site, multiple impacts over the lifetime of a parent body are likely to have occurred. Moreover, as most meteorite samples are on the centimeter to meter scale, the localized effects of impact heating cannot be ignored.Comment: 38 pages, 9 figures, Revised for Geochimica et Cosmochimica Acta (Sorry, they do not accept LaTeX

DeepFactors: Real-time probabilistic dense monocular SLAM

The ability to estimate rich geometry and camera motion from monocular imagery is fundamental to future interactive robotics and augmented reality applications. Different approaches have been proposed that vary in scene geometry representation (sparse landmarks, dense maps), the consistency metric used for optimising the multi-view problem, and the use of learned priors. We present a SLAM system that unifies these methods in a probabilistic framework while still maintaining real-time performance. This is achieved through the use of a learned compact depth map representation and reformulating three different types of errors: photometric, reprojection and geometric, which we make use of within standard factor graph software. We evaluate our system on trajectory estimation and depth reconstruction on real-world sequences and present various examples of estimated dense geometry

Design data collection with Skylab/EREP microwave instrument S-193

There are no author-identified significant results in this report

Following microscopic motion in a two dimensional glass-forming binary fluid

The dynamics of a binary mixture of large and small discs are studied at temperatures approaching the glass transition using an analysis based on the topology of the Voronoi polygon surrounding each atom. At higher temperatures we find that dynamics is dominated by fluid-like motion that involves particles entering and exiting the nearest-neighbour shells of nearby particles. As the temperature is lowered, the rate of topological moves decreases and motion becomes localised to regions of mixed pentagons and heptagons. In addition we find that in the low temperature state particles may translate significant distances without undergoing changes in their nearest neig hbour shell. These results have implications for dynamical heterogeneities in glass forming liquids.Comment: 12 pages, 7 figure

Bayesian uncertainty management in temporal dependence of extremes

Both marginal and dependence features must be described when modelling the extremes of a stationary time series. There are standard approaches to marginal modelling, but long- and short-range dependence of extremes may both appear. In applications, an assumption of long-range independence often seems reasonable, but short-range dependence, i.e., the clustering of extremes, needs attention. The extremal index 0 < ≤ 1 is a natural limiting measure of clustering, but for wide classes of dependent processes, including all stationary Gaussian processes, it cannot distinguish dependent processes from independent processes with = 1. Eastoe and Tawn (Biometrika 99, 43–55 2012) exploit methods from multivariate extremes to treat the subasymptotic extremal dependence structure of stationary time series, covering both 0 < <1 and = 1, through the introduction of a threshold-based extremal index. Inference for their dependence models uses an inefficient stepwise procedure that has various weaknesses and has no reliable assessment of uncertainty. We overcome these issues using a Bayesian semiparametric approach. Simulations and the analysis of a UK daily river flow time series show that the new approach provides improved efficiency for estimating properties of functionals of clusters