Studies on the immune response of the ovine respiratory tract toparainfluenza 3 virus

Ovine IgG, IgM and IgA and antisera specific for these immunoglobulins were prepared. These reagents were used to estimate immunoglobulin levels in sheep sera and certain other body fluids including the respiratory secretions. The results showed that a secretory IgA system existed in the ovine respiratory tract. Furthermore IgA antibodies to Mycoplasma ovipneumonia were identified in the lung fluid of a sheep clinically affected with pulmonary adenomatosis. IgA antibodies specific for Parainfluenza 3 were demonstrated in the respiratory secretions of lambs which had been experimentally infected with the virus. A large molecular weight non-immunoglobulin substance, which inhibited Parainfluenza 3 and three other paramyxoviruses, was also identified in the respiratory secretions of both conventionally reared and specific pathogen free lambs. It is suggested that in certain reports non-specific inhibitors present in the nasal secretions of calves may have been confused with Parainfluenza 3 specific IgA antibody. Attempts were made to define the protective role of nasal secretion antibody with vaccination-challenge experiments in specific pathogen free lambs. It was shown that live Parainfluenza 3 administered intranasally stimulated comparable serum antibody titres but higher nasal secretion titres than the same dose of live virus given intramuscularly. Inactivated virus inoculated without adjuvant by either route stimulated low or undetectable serum titres and no nasal antibody. Immunity to aerosol challenge, as assessed by viral shedding from the nose and changes in post challenge antibody titres, was best conferred by intranasal inoculation with live virus. Hence there was some evidence that the presence of antibody in the nasal secretions reduced the susceptibility to infection. In subsequent experiments it was found that intramuscular inoculation of inactivated Parainfluenza 3 in complete Freund's adjuvant stimulated high serum and nasal secretion titres, which protected against challenge. However the nasal secretion antibody was IgG^, which was possibly selectively transferred from serum. This contrasted with the earlier finding of IgA antibodies in the respiratory secretions after intranasal inoculation of live virus and showed that a second mucous antibody system existed in the ovine respiratory tract. Results from an experiment with young colostrum fed lambs indicated that maternal antibody alone could prevent infection with Parainfluenza 3 virus. This showed that the presence of cell-mediated immunity may not be essential to prevent sheep becoming infected with this virus. In this and a subsequent experiment it was demonstrated that colostral IgG passed into the nasal and lachrymal secretions of young lambs. This finding supported the earlier suggestion that IgG1 is selectively transferred from serum into the nasal secretions of young lambs. It is suggested that the presence of maternal IgG1 antibodies in the respiratory secretions of newborn suckled lambs could constitute an important defence mechanism against respiratory infections before local antibody synthesis begins at about two weeks of age

The Return of Large Dams to the Development Agenda: A Post-Development Critique

Large dams are making a comeback. Large dams reflect an outdated development paradigm narrowly focused on economic growth through modernization. This article employs a post-development lens to highlight three biases of the narrow development perspective that underlies large dams. First, it views rivers, and nature more generally, as an unrealized source of economic growth and an input to production. Second, it is blind to distributional impacts and is resultantly inequitable: the benefits of large dams are concentrated in the hands of the wealthy, while conditions for the poor do not improve and often worsen. Third, it disempowers those supposedly being developed by de-politicizing the development decisions to pursue large dam projects. Each of these biases is illustrated by reference to the Mekong River Basin’s experience with large dam development. It is concerning, therefore, that large dams seem to be making a resurgence in Asia, Africa and South America, and are once again receiving World Bank support. This article serves as a reminder of why large dams do not deliver equitable development and faded from the development agenda at the turn of the century

Developments and hurdles in generating vaccines for controlling helminth parasites of grazing ruminants

As a direct consequence of rising drug resistance among common nematodes of grazing animals, efforts toward state-of-the- art vaccine development have clearly intensified in recent years, fuelled primarily by the advent of newer technologies in gene discovery, by advancements in antigen identification, characterisation and production. In this regard, it is appropriate to review progress that has been made in generating helminth vaccines and in particular, vaccines against common nematodes of production animals for consumption. In like manner, it is prudent to evaluate barriers that have hindered progress in the past and continue to present obstacles that must be solved when utilizing and depending on host immunity to attenuate parasitic infections

Spectrum of TeV Particles in Warped Supersymmetric Grand Unification

In warped supersymmetric grand unification, XY gauge particles appear near the TeV scale along with Kaluza-Klein towers of the standard model gauge fields. In spite of this exotic low-energy physics, MSSM gauge coupling unification is preserved and proton decay is naturally suppressed. In this paper we study in detail the low-lying mass spectrum of superparticles and GUT particles in this theory, taking supersymmetry breaking to be localized to the TeV brane. The masses of the MSSM particles, Kaluza-Klein modes, and XY states are all determined by two parameters, one which fixes the strength of the supersymmetry breaking and the other which sets the scale of the infrared brane. A particularly interesting result is that for relatively strong supersymmetry breaking, the XY gauginos and the lowest Kaluza-Klein excitations of the MSSM gauginos may both lie within reach of the LHC, providing the possibility that the underlying unified gauge symmetry and the enhanced N=2 supersymmetry of the theory will both be revealed.Comment: 29 pages, 5 figure

Discrete-time rewards model-checked

This paper presents a model-checking approach for analyzing discrete-time Markov reward models. For this purpose, the temporal logic probabilistic CTL is extended with reward constraints. This allows to formulate complex measures – involving expected as well as accumulated rewards – in a precise and succinct way. Algorithms to efficiently analyze such formulae are introduced. The approach is illustrated by model-checking a probabilistic cost model of the IPv4 zeroconf protocol for distributed address assignment in ad-hoc networks

Varieties of distributive rotational lattices

A rotational lattice is a structure (L;\vee,\wedge, g) where L=(L;\vee,\wedge) is a lattice and g is a lattice automorphism of finite order. We describe the subdirectly irreducible distributive rotational lattices. Using J\'onsson's lemma, this leads to a description of all varieties of distributive rotational lattices.Comment: 7 page

Strategies for the evolution of sex

We find that the hypothesis made by Jan, Stauffer and Moseley [Theory in Biosc., 119, 166 (2000)] for the evolution of sex, namely a strategy devised to escape extinction due to too many deleterious mutations, is sufficient but not necessary for the successful evolution of a steady state population of sexual individuals within a finite population. Simply allowing for a finite probability for conversion to sex in each generation also gives rise to a stable sexual population, in the presence of an upper limit on the number of deleterious mutations per individual. For large values of this probability, we find a phase transition to an intermittent, multi-stable regime. On the other hand, in the limit of extremely slow drive, another transition takes place to a different steady state distribution, with fewer deleterious mutations within the asexual population.Comment: RevTeX, 11 pages, multicolumn, including 12 figure

High Bone Mass is associated with bone-forming features of osteoarthritis in non-weight bearing joints independent of body mass index

Objectives: High Bone Mass (HBM) is associated with (a) radiographic knee osteoarthritis (OA), partly mediated by increased BMI, and (b) pelvic enthesophytes and hip osteophytes, suggestive of a bone-forming phenotype. We aimed to establish whether HBM is associated with radiographic features of OA in non weight-bearing (hand) joints, and whether such OA demonstrates a bone-forming phenotype. Methods: HBM cases (BMD Z-scores ≥+3.2) were compared with family controls. A blinded assessor graded all PA hand radiographs for: osteophytes (0-3), joint space narrowing (JSN)(0-3), subchondral sclerosis (0-1), at the index Distal Interphalangeal Joint (DIPJ) and 1st Carpometacarpal Joint (CMCJ), using an established atlas. Analyses used a random effects logistic regression model, adjusting a priori for age and gender. Mediating roles of BMI and bone turnover markers (BTMs) were explored by further adjustment. Results: 314 HBM cases (mean age 61.1years, 74% female) and 183 controls (54.3years, 46% female) were included. Osteophytes (grade≥1) were more common in HBM (DIPJ: 67% vs. 45%, CMCJ: 69% vs. 50%), with adjusted OR [95% CI] 1.82 [1.11, 2.97], p=0.017 and 1.89 [1.19, 3.01], p=0.007 respectively; no differences were seen in JSN. Further adjustment for BMI failed to attenuate ORs for osteophytes in HBM cases vs. controls; DIPJ 1.72 [1.05, 2.83], p=0.032, CMCJ 1.76 [1.00, 3.06], p=0.049. Adjustment for BTMs (concentrations lower amongst HBM cases) did not attenuate ORs. Conclusions: HBM is positively associated with OA in non weight-bearing joints, independent of BMI. HBMassociated OA is characterised by osteophytes, consistent with a bone-forming phenotype, rather than JSN reflecting cartilage loss. Systemic factors (e.g. genetic architecture) which govern HBM may also increase bone-forming OA risk

Electromagnetic Dissociation of Nuclei in Heavy-Ion Collisions

Large discrepancies have been observed between measured Electromagnetic Dissociation(ED) cross sections and the predictions of the semiclassical Weiz\"acker-Williams-Fermi(WWF) method. In this paper, the validity of the semiclassical approximation is examined. The total cross section for electromagnetic excitation of a nuclear target by a spinless projectile is calculated in first Born approximation, neglecting recoil. The final result is expressed in terms of correlation functions and convoluted densities in configuration space. The result agrees with the WWF approximation to leading order(unretarded electric dipole approximation), but the method allows an analytic evaluation of the cutoff, which is determined by the details of the electric dipole transition charge density. Using the Goldhaber-Teller model of that density, and uniform charge densities for both projectile and target, the cutoff is determined for the total cross section in the nonrelativistic limit, and found to be smaller than values currently used for ED calculations. In addition, cross sections are calculated using a phenomenological momentum space cutoff designed to model final state interactions. For moderate projectile energies, the calculated ED cross section is found to be smaller than the semiclassical result, in qualitative agreement with experiment.Comment: 28 page

Sexual signalling in an artificial population: When does the handicap principle work?

Males may use sexual displays to signal their quality to females; the handicap principle provides a mechanism that could enforce honesty in such cases. Iwasa et al. model the signalling of inherited male quality, and distinguish between three variants of the handicap principle: pure epistasis, conditional, and revealing They argue that only the second and third will work. An evolutionary simulation is presented in which all three variants function under certain conditions; the assumptions made by Iwasa et al. are questioned