THIRD INTERNATIONAL SYMPOSIUM ON RANAVIRUSES:: ADVANCING THE UNDERSTANDING OF THE THREAT OF RANAVIRUSES TO NORTH AMERICAN HERPETOFAUNA

Members of the genus Ranavirus, one of five genera withinthe family Iridoviridae, encompass a group of large, doublestrandedDNA viruses that infect all three classes of ectothermicvertebrates: fish, amphibians, and reptiles. Ranaviruses areglobally emerging pathogens that cause considerable morbidityand mortality among diverse populations. In North America,ranavirus epizootics are regularly reported in wild and culturedfish, amphibian, and reptile populations

Quantum tunnelling of magnetization in Mn12-ac studied by 55Mn NMR

We present an ultra-low temperature study (down to T = 20 mK) of the nuclear spin-lattice relaxation (SLR) in the 55Mn nuclei of the molecular magnet Mn12-ac. The nuclear spins act as local probes for the electronic spin fluctuations, due to thermal excitations and to tunnelling events. In the quantum regime (below T = 0.75 K), the nuclear SLR becomes temperature-independent and is driven by fluctuations of the cluster's electronic spin due to the quantum tunnelling of magnetization in the ground doublet. The quantitative analysis of the nuclear SLR shows that the presence of fast-tunnelling molecules, combined with nuclear intercluster spin diffusion, plays an important role in the relaxation process.Comment: RevTex, 5 pages, 3 eps figures; presented at the Internation Conference on Molecular Magnets (Valencia, 5 - 10 Oct. 2002); to be published in Polyhedro

Evaluation of the Removal of Organic Sulfur from Coal

As the removal of sulfur from coal prior to combustion acquires more importance in order to meet evermore stringent antipollution regulations, research on the development of methods for the cleaning of coal continues to expand. Reviews are available which describe the various methods for desulfurizing coal (1, 2, 3). The sulfur content in coal is usually a few per cent, but it can range from less than 0.5 per cent to as much as 8 per cent or more. Much of the sulfur is inorganic in nature, occurring in discrete mineral phases; the inorganic sulfur is mostly pyrite with small amounts of sulfates such as gypsum. Part of the sulfur in coal is termed organic sulfur, being intimately bound to the organic coal matrix. The chemical nature of this organic sulfur is not well established. During the desulfurization of coal, some of the coarse inorganic sulfur components can be removed

Chiral multiplets versus parity doublets in highly excited baryons

It has recently been suggested that the parity doublet structure seen in the spectrum of highly excited baryons may be due to effective chiral restoration for these states. We argue how the idea of chiral symmetry restoration high in the spectrum is consistent with the concept of quark-hadron duality. If chiral symmetry is effectively restored for highly-lying states, then the baryons should fall into representations of $SU(2)_L\times SU(2)_R$ that are compatible with the given parity of the states - the parity-chiral multiplets. We classify all possible parity-chiral multiplets: (i) $(1/2,0)\oplus(0, 1/2)$ that contain parity doublet for nucleon spectrum;(ii) $(3/2,0) \oplus (0, 3/2)$ consists of the parity doublet for delta spectrum; (iii) $(1/2,1) \oplus (1, 1/2)$ contains one parity doublet in the nucleon spectrum and one parity doublet in the delta spectrum of the same spin that are degenerate in mass. Here we show that the available spectroscopic data for nonstrange baryons in the $\sim$ 2 GeV range is consistent with all possibilities, but the approximate degeneracy of parity doublets in nucleon and delta spectra support the latter possibility with excited baryons approximately falling into $(1/2,1) \oplus (1, 1/2)$ representation of SU(2)_L\timesSU(2)_R with approximate degeneracy between positive and negative parity $N$ and $\Delta$ resonances of the same spin.Comment: RevTeX, 6 pages. The paper has been expanded in order to make the idea of chiral symmetry restoration as it follows from the concept of quark-hadron duality more transparent. To appear in Phys. Rev.

A role for tetraspanin proteins in regulating fusion induced by Burkholderia thailandensis

Burkholderia pseudomallei is the causative agent of melioidosis, a disease with high morbidity that is endemic in South East Asia and northern Australia. An unusual feature of the bacterium is its ability to induce multinucleated giant cell formation (MNGC), which appears to be related to bacterial pathogenicity. The mechanism of MNGC formation is not fully understood, but host cell factors as well as known bacterial virulence determinants are likely to contribute. Since members of the tetraspanin family of membrane proteins are involved in various types of cell:cell fusion, their role in MNGC formation induced by Burkholderia thailandensis, a mildly pathogenic species closely related to B. pseudomallei, was investigated. The effect of antibodies to tetraspanins CD9, CD81, and CD63 in MNGC formation induced by B. thailandensis in infected mouse J774.2 and RAW macrophage cell lines was assessed along with that of recombinant proteins corresponding to the large extracellular domain (EC2) of the tetraspanins. B. thailandensis-induced fusion was also examined in macrophages derived from CD9 null and corresponding WT mice, and in J774.2 macrophages over-expressing CD9. Antibodies to CD9 and CD81 promoted MNGC formation induced by B. thailandensis, whereas EC2 proteins of CD9, CD81, and CD63 inhibited MNGC formation. Enhanced MNGC formation was observed in CD9 null macrophages, whereas a decrease in MNGC formation was associated with overexpression of CD9. Overall our findings show that tetraspanins are involved in MNGC formation induced by B. thailandensis and by implication, B. pseudomallei, with CD9 and CD81 acting as negative regulators of this process

A within farm clinical trial to compare two treatments (parenteral antibacterials and hoof trimming) for sheep lame with footrot

From observational studies, farmers who use parenteral antibacterials to promptly treat all sheep with footrot (FR) or interdigital dermatitis (ID) have a prevalence of lameness of <2% compared with a prevalence of 9% lameness reported by farmers who treat lame sheep by trimming affected feet. We tested the hypothesis that prompt treatment of sheep lame with naturally developing FR or ID with parenteral and topical antibacterials reduces the prevalence and incidence of lameness with these conditions compared with less frequent treatment with trimming of hoof horn and applying topical antibacterials. A further hypothesis was that reduction of ID and FR would improve productivity. A lowland sheep flock with 700 ewes was used to test these hypotheses in an 18-month within farm clinical trial with four groups of ewes: two intervention and two control. The duration and severity of lameness was used to categorise sheep into three weighted scores of lameness (WLS): never lame (WLS0), mildly lame/lame for <6 days (WLS1) and severely or chronically lame (WLS2). The intervention reduced the prevalence of lameness due to FR and ID in ewes and lambs and the incidence of lameness in ewes. The WLS was also significantly lower in sheep in the intervention groups. Ewes with a higher WLS were subsequently significantly more likely to have a body condition score <2.5 and to have lame lambs. Significantly more ewes lambed and successfully reared more lambs that were ready for slaughter at a younger age in the intervention versus control groups. There was an increase in the gross margin of £630/100 ewes mated in the intervention group, including the cost of treatment of £150/100 ewes mated. We conclude that prompt parenteral and topical antibacterial treatment of sheep lame with ID and FR reduced the prevalence and incidence of these infectious conditions and led to improved health, welfare and productivity

Factors associated with changes of state of foot conformation and lameness in a flock of sheep

The aim of this research was to investigate transitions between foot conformation, lameness and footrot in sheep. Data came from one lowland flock of approximately 700 ewes studied for 18 months. Multilevel multistate analyses of transitions between good and poor foot conformation states in ewes, and lame and non-lame states in ewes and lambs were conducted. Key results were that the longer sheep had feet in good conformation, the more likely they were to stay in this state; similarly, the longer a ewe was not lame the more likely she was not to become lame. Ewes with poor foot conformation were more likely to become lame (OR: 1.83 (1.24-2.67)) and to be > 4 years (OR: 1.50(1.09-2.05)). Ewes with footrot were less likely to move to good foot conformation (OR: 0.48 (0.31-0.75)) and were more likely to become lame (OR: 3.81(2.60-5.59)). Ewes lame for > 4 days and not treated with parenteral antibacterials had a higher risk of developing (OR: 2.00 (1.08-3.61)), or remaining in (OR: 0.49 (0.29-0.95)) poor foot conformation compared with ewes never lame. Treatment of ewes lame with footrot with parenteral antibacterials increased the probability of transition from a lame to a non-lame state (OR: 1.46 (1.05-2.02)) and these ewes, even if lame for > 4 days, were not more likely to develop poor foot conformation. The risk of a ewe becoming lame increased when at least one of her offspring was lame (OR: 2.03 (1.42-2.92)) and when the prevalence of lameness in the group was ≥ 5% (OR: 1.42 (1.06-1.92)). Lambs were at increased risk of becoming lame when they were male (OR: 1.42 (1.01-2.01)), single (OR: 1.86 (1.34-2.59)) or had a lame dam or sibling (OR: 3.10 (1.81-5.32)). There were no explanatory variables associated with lambs recovering from lameness. We conclude that poor foot conformation in ewes increases the susceptibility of ewes to become lame and that this can arise from untreated footrot. Treatment of ewes lame with footrot with parenteral antibacterials leads to recovery from lameness and prevents or resolves poor foot conformation which then reduces the susceptibility to further lameness with footrot

Higher dimensional supersymmetry in 4D superspace

We present an explicit formulation of supersymmetric Yang-Mills theories from \D= 5 to 10 dimensions in the familiar \N=1,\D=4 superspace. This provides the rules for globally supersymmetric model building with extra dimensions and in particular allows us to simply write down $\N=1$ SUSY preserving interactions between bulk fields and fields localized on branes. We present a few applications of the formalism by way of illustration, including supersymmetric ``shining'' of bulk fields, orbifolds and localization of chiral fermions, anomaly inflow and super-Chern-Simons theories.Comment: Typos corrected. Added reference to early work by Marcus, Sagnotti and Siegel and a term to the non-Abelian Lagrangian for D>5 formally needed for gauge invariance. The results however remain unchange

Supersymmetric Gauge Theories in Twistor Space

We construct a twistor space action for N=4 super Yang-Mills theory and show that it is equivalent to its four dimensional spacetime counterpart at the level of perturbation theory. We compare our partition function to the original twistor-string proposal, showing that although our theory is closely related to string theory, it is free from conformal supergravity. We also provide twistor actions for gauge theories with N<4 supersymmetry, and show how matter multiplets may be coupled to the gauge sector.Comment: 23 pages, no figure

Accepting higher morbidity in exchange for sacrificing fewer animals in studies developing novel infection-control strategies.

Preventing bacterial infections from becoming the leading cause of death by the year 2050 requires the development of novel, infection-control strategies, building heavily on biomaterials science, including nanotechnology. Pre-clinical (animal) studies are indispensable for this development. Often, animal infection outcomes bear little relation to human clinical outcome. Here, we review conclusions from pathogen-inoculum dose-finding pilot studies for evaluation of novel infection-control strategies in murine models. Pathogen-inoculum doses are generally preferred that produce the largest differences in quantitative infection outcome parameters between a control and an experimental group, without death or termination of animals due to having reached an inhumane end-point during the study. However, animal death may represent a better end-point for evaluation than large differences in outcome parameters or number of days over which infection persists. The clinical relevance of lower pre-clinical outcomes, such as bioluminescence, colony forming units (CFUs) retrieved or more rapid clearance of infection is unknown, as most animals cure infection without intervention, depending on pathogen-species and pathogen-inoculum dose administered. In human clinical practice, patients suffering from infection present to hospital emergency wards, frequently in life-threatening conditions. Animal infection-models should therefore use prevention of death and recurrence of infection as primary efficacy targets to be addressed by novel strategies. To compensate for increased animal morbidity and mortality, animal experiments should solely be conducted for pre-clinical proof of principle and safety. With the advent of sophisticated in vitro models, we advocate limiting use of animal models when exploring pathogenesis or infection mechanisms