Herpes virus infection of pigeons

The thesis reports the isolation of a herpesvirus from two outbreaks of disease among racing pigeons in the West of Scotland. In both outbreaks the infection seemed to be enzootic and was probably maintained by healthy adult carriers. Thus, although each flock was self-contained, the disease recurred annually in both lofts over several years and only involved birds of five to six weeks of age. Clinical signs included serious conjunctivitis and rhinitis, weakness and general malaise. Some birds were dyspnoeic, probably due to the presence of small diphtheritic patches on the mucous membrane of the larynx. The most constant post-mortem finding was focal hepatic necrosis, but renal necrosis was also noted in some birds. Basophilic or slightly eosinophilic intranuclear inclusions were found in parenchymal cells adjacent to the necrotic foci and were also noted occasionally in epithelial cells adjacent to exudate-coated ulcers in the pharynx and larynx. Examinations for the ornithosis agent proved negative, but small whitish-cream pocks were produced on the chorio-allantoic membranes of ten-day embryonated hens' eggs inoculated with tissue suspensions from six birds and with a throat swab from a seventh. Embryos became sluggish and often died about the fifth day. The pocks produced by all isolates generally attained a maximum diameter of 1 mm. on the fourth day, but dendritic extensions were sometimes present. Intranuclear inclusions, typical of those produced by herpesviruses, were prominent in ectodermal cells on the second day, but diminished in number thereafter and, by the fifth day, were almost entirely absent. Foci of necrosis in the embryonic liver could often be appreciated macroscopically by the fourth day. Intranuclear inclusions were present in hepatic cells adjacent to those food. Hepatic necrosis was a regular finding in embryos inoculated by the yolk-sac route and also sometimes occurred in embryos infected amniotically, but the virus could not be propagated by allantoic inoculation. All isolates were cytopathogenic in whole chick-embryo cultures, the cytopathogenic effect (C.P.C.) being characterized by the appearances of foci of round, refractive cells, some of which were considerably swollen. With concentrated inocula, the C.P.E. appeared within 24 hours and the monolayer was completely destroyed by the fourth or fifth day with release of virus into the culture-fluids. The agent was cytopathogenic in cultures of chick-embryo kidney, chick-embryo liver, chicken kidney and pigeon kidney but did not multiply in HeLa cells, in Strain L cells on in primary cultures of dog or calf kidney. The C.P.E. was essentially the same in all avain cultures employed. In contrast to the above findings, a strain of infectious laryngo-tracheitis (I.L.T.) virus was found to produce small syncytia in the epithelial component of whole-embryo cultures but no C.P.E. in fibroblasts. Intermediate in its effects was the P-5 strain of pigoon I.N.I. virus isolated by Smadel et al. in 1945. This strain, kindly supplied to the writer, produced small syncytia in the epithelial component of whole-embryo cultures and rounding of the fibroblasts. All isolates produced plaques in whole-embryo cultures maintained under an agar overlay. These appeared on the second or third day and by the fourth day; varied in diameter from 0.5 mm. to 2 mm. though the largest did not increase in size thereafter. Although "small-plaque" variants were found to be present, much of the variations in plaque-diameter was shown to be non-genetic in character. A linear relationship was found to exist between plaque-count and virus input and evidence was obtained to indicate that the distribution of plaques follows the Poisson equation. Replicate assays of stock virus gave approximately the same titre in cultures of different batches. The ratio of plaque-forming to pock-forming was found to be around 1.5 to 1. Plaques were also formed under methylcellulose, the relationship between plaque-count and relative virus concentration again being linear. The plating-efficiency under methylcellulose was approximately double that under agar. About 50 percent of the virus attached to monolayers of whole-embryo cells in 95 minutes but absorption was not complete before the end of the sixth hour. The DNA nature of the virus was demonstrated by inhibition with bromo- and iodo-deoxyuridines. By means of the negative staining techniques of electron microscopy, the virion was shown to be typical of that of the herpesvirus group. The virus was other-sensitive and was destroyed by exposure to a pH of 4.0. It was quickly destroyed at 5

Spin-orbit coupling and crystal-field splitting in the electronic and optical properties of nitride quantum dots with a wurtzite crystal structure

We present an $sp^3$ tight-binding model for the calculation of the electronic and optical properties of wurtzite semiconductor quantum dots (QDs). The tight-binding model takes into account strain, piezoelectricity, spin-orbit coupling and crystal-field splitting. Excitonic absorption spectra are calculated using the configuration interaction scheme. We study the electronic and optical properties of InN/GaN QDs and their dependence on structural properties, crystal-field splitting, and spin-orbit coupling.Comment: 9 pages, 6 figure

FracPaQ: A MATLAB™ toolbox for the quantification of fracture patterns

The patterns of fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, and spatial distributions often exhibit some kind of order. In detail, relationships may exist among the different fracture attributes, e.g. small fractures dominated by one orientation, larger fractures by another. These relationships are important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture attributes and patterns. This paper describes FracPaQ, a new open source, cross-platform toolbox to quantify fracture patterns, including distributions in fracture attributes and their spatial variation. Software has been developed to quantify fracture patterns from 2-D digital images, such as thin section micrographs, geological maps, outcrop or aerial photographs or satellite images. The toolbox comprises a suite of MATLAB™ scripts based on previously published quantitative methods for the analysis of fracture attributes: orientations, lengths, intensity, density and connectivity.An estimate of permeability in 2-D is made using a parallel plate model. The software provides an objective and consistent methodology for quantifying fracture patterns and their variations in 2-D across a wide range of length scales, rock types and tectonic settings. The implemented methods presented are inherently scale independent, and a key task where applicable is analysing and integrating quantitative fracture pattern data from micro-to macro-scales. The toolbox was developed in MATLAB™ and the source code is publicly available on GitHub™ and the Mathworks™ FileExchange. The code runs on any computer with MATLAB installed, including PCs with Microsoft Windows, Apple Macs with Mac OS X, and machines running different flavours of Linux. The application, source code and sample input files are available in open repositories in the hope that other developers and researchers will optimise and extend the functionality for the benefit of the wider community

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Bio-Psycho-Social Reasoning in GPs’ Case Narratives: The Discursive Construction of ME Patients’ Identities

This article takes a discursive psychology approach to the analysis of medical case narratives. An analysis of interview extracts on the topic of ME (CFS)shows how GPs use bio-psycho-social reasoning to construct the patient's identity and to define their illness as mental or physical. Patients' identities are 'talked up' using bio-psycho-social 'evidence'; they are constructed in the process of explaining the origins of an illness as mental or physical. This has much in common with identity construction in the illness narratives of ME patients. The analysis also shows how identity construction can function as a justification for defining an illness as psychosomatic and effectively 'shifting the blame' for what might otherwise be treated as medical failure or uncertainty. These processes show how a discursive analysis can shed more light on how bio-psycho-social reasoning functions in doctors' case constructions