Application of ribotyping and IS<i>200</i> fingerprinting to distinguish the five <i>Salmonella</i> serotype O6,7:c:1,5 groups: Choleraesuis <i>sensu stricto</i>, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis

Sixty-seven strains of the five described Salmonella serotypes having antigens 6,7:c: 1,5, that is S. enterica serotype Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis, were examined for 16S rrn profile ribotype, presence of IS200 and phenotypic characters, including rate of change of flagellar-antigen phase and nutritional character. Choleraesuis sensu stricto and its Kunzendorf variant had related but distinct ribotypes. Therefore, ribotyping appears to be a suitable method for differentiating Choleraesuis non-Kunzendorf from Choleraesuis var. Kunzendorf. Some strains of Paratyphi C had 16S profiles that resembled that of Choleraesuis non-Kunzendorf, while others resembled that of Choleraesuis var. Kunzendorf. The Typhisuis profiles were like those of Choleraesuis non-Kunzendorf, while the Choleraesuis var. Decatur profiles were unlike those of any of the other four groups. Furthermore, IS200 fingerprinting discriminated between Choleraesuis var. Decatur and the other strains with antigenic formula O6,7:c: 1,5, and comparison of IS200 patterns showed a high degree of genetic divergence within Choleraesuis var. Decatur. Our findings show that ribotyping and IS200 fingerprinting, combined with classical microbiological methods, distinguish the groups Choleraesuis non-Kunzendorf, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C and Typhisuis

Fractal geometry of critical Potts clusters

Numerical simulations on the total mass, the numbers of bonds on the hull, external perimeter, singly connected bonds and gates into large fjords of the Fortuin-Kasteleyn clusters for two-dimensional q-state Potts models at criticality are presented. The data are found consistent with the recently derived corrections-to-scaling theory. However, the approach to the asymptotic region is slow, and the present range of the data does not allow a unique identification of the exact correction exponentsComment: 7 pages, 8 figures, Late

The impact of organic livestock standards on animal welfare – a questionnaire survey of advisors, inspectors and veterinarians

This report was presented at the UK Organic Research 2002 Conference. A questionnaire survey of organic sector body inspectors, organic advisors and farm animal veterinarians was conducted to examine the respondents’ perceptions of the ability of the organic standards to deliver positive impacts on welfare of organic livestock. A total of 44 separate standards concerning livestock production were extracted from the United Kingdom Register of Organic Food Production livestock production standards. The respondents were asked to consider the potential impact of each standard on animal welfare in comparison to the routine practices used on conventional farms, using a five-point scale (improve significantly, improve slightly, no impact, deteriorate slightly and deteriorate significantly). A simple scoring system was used to rank the different standards in terms of their perceived positive impact on animal welfare. The significance of differences between respondent groups and livestock species were examined. Preliminary findings of the survey are summarised and the usefulness of the approach to evaluate livestock production standards is discussed

Organic egg production in Finland - animal health, welfare and food safety issues

A total of 20 out of 23 commercial organic layer farms took part in the research. Data were collected through observation and by interviewing the producer, using a semi-structured interview guide. Laying hen welfare was estimated using environment-based and animal-based methods. Fresh faecal samples were collected from the floor for analysis of campylobacter and salmonella bacteria and for internal parasite identification

Organic egg production in Finland: management of animal welfare and food safety

A total of 20 out of 23 commercial organic layer farms (in excess of 80 % of all commercial Finnish organic farms year 2003) took part in the ongoing research, which identifies risk factors and potential solutions for laying hen welfare and food safety. Data was collected during two farm visits by interviewing the producer, using a semi-structured interview guide, making environment and animal-based observations and collecting samples

Characterization of seedling and adult-plant resistance to stem rust race Ug99 in Iranian bread wheat landraces

The full-length infectious cDNA clone was constructed and sequenced from the strain DM of echovirus 9, which was recently isolated from a 6-week-old child at the clinical onset of type 1 diabetes. Parallel with the isolate DM, the full-length infectious cDNA clone of the prototype strain echovirus 9 Barty (Barty-INF), was constructed and sequenced. Genetic relationships of the sequenced echo 9 viruses to the other members of the human enterovirus type B species were studied by phylogenetic analyses. Comparison of capsid protein sequences showed that the isolate DM was closely related to both prototype strains: Hill and Barty-INF. The only exception was the inner capsid protein VP4 where serotype specificity was not evident and the isolate DM clustered with the strain Hill and the strain Barty-INF with echovirus 30 Bastianni. Likewise, the nonstructural protein coding region, P2P3, of isolate DM was more similar to strain Hill than to strain Barty-INF. However, like echovirus 9 Barty, the isolate DM contained the RGD-motif in the carboxy terminus of capsid protein VP1. By blocking experiments using an RGD-containing peptide and a polyclonal rabbit antiserum to the alpha(v)beta(3)-integrin, it was shown that this molecule works as a cellular receptor for isolate DM. By using primary human islets, it was shown that the isolate DM is capable of infecting insulin-producing beta-cells like the corresponding prototype strains did. However, only isolate DM was clearly cytolytic for beta-cells. The infectious clones that were made allow further investigations of the molecular features responsible for the diabetogenicity of the isolate DM

Characterizing Width Uniformity by Wave Propagation

This work describes a novel image analysis approach to characterize the uniformity of objects in agglomerates by using the propagation of normal wavefronts. The problem of width uniformity is discussed and its importance for the characterization of composite structures normally found in physics and biology highlighted. The methodology involves identifying each cluster (i.e. connected component) of interest, which can correspond to objects or voids, and estimating the respective medial axes by using a recently proposed wavefront propagation approach, which is briefly reviewed. The distance values along such axes are identified and their mean and standard deviation values obtained. As illustrated with respect to synthetic and real objects (in vitro cultures of neuronal cells), the combined use of these two features provide a powerful description of the uniformity of the separation between the objects, presenting potential for several applications in material sciences and biology.Comment: 14 pages, 23 figures, 1 table, 1 referenc

Are the Tails of Percolation Thresholds Gaussians ?

The probability distribution of percolation thresholds in finite lattices were first believed to follow a normal Gaussian behaviour. With increasing computer power and more efficient simulational techniques, this belief turned to a stretched exponential behaviour, instead. Here, based on a further improvement of Monte Carlo data, we show evidences that this question is not yet answered at all.Comment: 7 pages including 3 figure

Percolation transition of hydration water at hydrophilic surfaces

An analysis of water clustering is used to study the quasi-2D percolation transition of water adsorbed at planar hydrophilic surfaces. Above the critical temperature of the layering transition (quasi-2D liquid-vapor phase transition of adsorbed molecules) a percolation transition occurs at some threshold surface coverage, which increases with increasing temperature. The location of the percolation line is consistent with the existence of a percolation transition at the critical point. The percolation threshold at a planar surface is weakly sensitive to the size of the system when its lateral dimension increases from 80 to 150 A. The size distribution of the largest water cluster shows a specific two-peaks structure in a wide range of surface coverage : the lower- and higher-size peaks represent contributions from non-spanning and spanning clusters, respectively. The ratio of the average sizes of spanning and non-spanning largest clusters is about 1.8 for all studied planes. The two-peak structure becomes more pronounced with decreasing size of the planar surface and strongly enhances at spherical surfaces.Comment: 17 pages, 11 figure

Beyond Blobs in Percolation Cluster Structure: The Distribution of 3-Blocks at the Percolation Threshold

The incipient infinite cluster appearing at the bond percolation threshold can be decomposed into singly-connected ``links'' and multiply-connected ``blobs.'' Here we decompose blobs into objects known in graph theory as 3-blocks. A 3-block is a graph that cannot be separated into disconnected subgraphs by cutting the graph at 2 or fewer vertices. Clusters, blobs, and 3-blocks are special cases of $k$-blocks with $k=1$, 2, and 3, respectively. We study bond percolation clusters at the percolation threshold on 2-dimensional square lattices and 3-dimensional cubic lattices and, using Monte-Carlo simulations, determine the distribution of the sizes of the 3-blocks into which the blobs are decomposed. We find that the 3-blocks have fractal dimension $d_3=1.2\pm 0.1$ in 2D and $1.15\pm 0.1$ in 3D. These fractal dimensions are significantly smaller than the fractal dimensions of the blobs, making possible more efficient calculation of percolation properties. Additionally, the closeness of the estimated values for $d_3$ in 2D and 3D is consistent with the possibility that $d_3$ is dimension independent. Generalizing the concept of the backbone, we introduce the concept of a ``$k$-bone'', which is the set of all points in a percolation system connected to $k$ disjoint terminal points (or sets of disjoint terminal points) by $k$ disjoint paths. We argue that the fractal dimension of a $k$-bone is equal to the fractal dimension of $k$-blocks, allowing us to discuss the relation between the fractal dimension of $k$-blocks and recent work on path crossing probabilities.Comment: All but first 2 figs. are low resolution and are best viewed when printe