Risk of foot and mouth disease associated with proximity in space and time to infected premises and the implications for control policy during the 2001 epidemic in Cumbria

An analysis was made that calculated the risk of disease for premises in the most heavily affected parts of the county of Cumbria during the foot-and-mouth disease epidemic in the UK in 2001. In over half the cases the occurrence of the disease was not directly attributable to a recently infected premises being located within 1.5 km. Premises more than 1.5 km from recently infected premises faced sufficiently high infection risks that culling within a 1.5 km radius of the infected premises alone could not have prevented the progress of the epidemic. A comparison of the final outcome in two areas of the county, south Penrith and north Cumbria, indicated that focusing on controlling the potential spread of the disease over short distances by culling premises contiguous to infected premises, while the disease continued to spread over longer distances, may have resulted in excessive numbers of premises being culled. Even though the contiguous cull in south Penrith appeared to have resulted in a smaller proportion of premises becoming infected, the overall proportion of premises culled was considerably greater than in north Cumbria, where, because of staff and resource limitations, a smaller proportion of premises contiguous to infected premises was culled

Disease-weather relationships for powdery mildew and yellow rust on winter wheat

Key weather factors determining the occurrence and severity of powdery mildew and yellow rust epidemics on winter wheat were identified. Empirical models were formulated to qualitatively predict a damaging epidemic (>5% severity) and quantitatively predict the disease severity given a damaging epidemic occurred. The disease data used was from field experiments at 12 locations in the UK covering the period from 1994 to 2002 with matching data from weather stations within a 5 km range. Wind in December to February was the most influential factor for a damaging epidemic of powdery mildew. Disease severity was best identified by a model with temperature, humidity, and rain in April to June. For yellow rust, the temperature in February to June was the most influential factor for a damaging epidemic as well as for disease severity. The qualitative models identified favorable circumstances for damaging epidemics, but damaging epidemics did not always occur in such circumstances, probably due to other factors such as the availability of initial inoculum and cultivar resistance.

Extraction behavior of nickel(II) using some of the BTBP-class ligands

Recently the BTBP-family of solvating ligands have been studied for their ability to separate trivalent actinides from lanthanides. Five of the BTBPs were evaluated for their ability to extract nickel(II) from aqueous nitrate media into cyclohexanone. It was shown by both solvent extraction and X-ray diffraction experiments that the BTBPs are capable of forming both 1: 1 and 1:2 complexes with nickel(II). When the BTBP concentration is low the nickel distribution ratio is governed by the formation of the nickel/BTBP complex while at higher BTBP concentrations the partitioning of the nickel complex between the two phases dictates the nickel distribution ratio.

An HMV mapping study of a pulsating jet system

A new system for the generation of hydrodynamic modulated voltammetry (HMV) is presented. This system consists of an oscillating jet produced through the mechanical vibration of a large diaphragm. The structure of the cell is such that a relatively small vibration is transferred to a large fluid flow at the jet outlet. Positioning of an electrode (Pt, 0.5 mm or 25 mu m diameter) over the exit of this jet enables the detection of the modulated flow of liquid. While this flow creates modest mass transfer rates (time averaged similar to 0.015 cm s(-1)) it can also be used to create a HMV system where a 'lock-in' approach is adopted to investigate the redox chemistry in question. This is demonstrated for the Fe(CN)(6)(3-/4-) redox system. Here 'lock-in' to the modulated hydrodynamic signal is achieved through the deployment of bespoke software. The apparatus and procedure is shown to produce a simple and efficient way to obtain the desired signal. In addition the spatial variation of the HMV signal, phase correction and time averaged current with respect to the jet orifice is presented. (C) 2008 Elsevier B.V. All rights reserved.

The production, purification and characterisation of two novel alpha-D-mannosidases from Aspergillus phoenicis

1,6-alpha-D-Mannosidase from Aspergillits phoenicis was purified by anion-exchange chromatography, chromatofocussing and size-exclusion chromatography. The apparent molecular weight was 74 kDa by SDS-PAGE and 81 kDa by native-PAGE. The isoelectric point was 4.6. 1,6-alpha-D-Mannosidase had a temperature optimum of 60 degrees C, a pH optimum of 4.0-4.5. a K-m of 14 mM with alpha-D-Manp-(1 -> 6)-D-Manp as substrate. It was strongly inhibited by Mn2+ and did not need Ca2+ or any other metal cofactor of those tested. The enzyme cleaves specifically (1 -> 6)-linked mannobiose and has no activity towards any other linkages, p-nitrophenyl-alpha-D-mannopyranoside or baker's yeast mannan. 1,3(1,6)-alpha-D-Mannosidase from A. phoenicis was purified by anion-exchange chromatography, chromatofocus sing and size-exclusion chromatography. The apparent molecular weight was 97 kDa by SDS-PAGE and 110 kDa by native-PAGE. The 1,3(1,6)-alpha-D-mannosidase enzyme existed as two charge isomers or isoforms. The isoelectric points of these were 4.3 and 4.8 by isoelectric focussing. It cleaves alpha-D-Manp-(1 -> 3)-D-Manp 10 times faster than alpha-D-Manp-(1 -> 6)-D-Manp, has very low activity towards p-nitrophenyl-alpha-D-mannopyranoside and baker's yeast mannan, and no activity towards alpha-D-Manp-(1 -> 2)-D-Manp. The activity towards (1 -> 3)-linked mannobiose is strongly activated by 1 mM Ca2+ and inhibited by 10 mM EDTA, while (1 -> 6)-activity is unaffected, indicating that the two activities may be associated with different polypeptides. It is also possible that one polypeptide may have two active sites catalysing distinct activities. (c) 2005 Elsevier Ltd. All rights reserved.

The psychological, neurochemical and functional neuroanatomical mediators of the effects of positive and negative mood on executive functions

In this review we evaluate the cognitive and neural effects of positive and negative mood on executive function. Mild manipulations of negative mood appear to have little effect on cognitive control processes, whereas positive mood impairs aspects of updating, planning and switching. These cognitive effects may be linked to neurochemistry: with positive mood effects mediated by dopamine while negative mood effects may be mediated by serotonin levels. Current evidence on the effects of mood on regional brain activity during executive functions, indicates that the prefrontal cortex is a recurrent site of integration between mood and cognition. We conclude that there is a disparity between the importance of this topic and awareness of how mood affects, executive functions in the brain. Most behavioural and neuroimaging studies of executive function in normal samples do not explore the potential role of variations in mood, yet the evidence we outline indicates that even mild fluctuations in mood can have a significant influence on neural activation and cognition. (c) 2006 Elsevier Ltd. All rights reserved.

Living with ASD: how do children and their parents assess their difficulties with social interaction and understanding?

Social interaction and understanding in autistic spectrum disorder (ASD) are key areas of concern to practitioners and researchers alike. However, there is a relative lack of information about the skills and competencies of children and young people with ASD who access ordinary community facilities including mainstream education. In particular, contributions by parents and their children have been under-utilized. Using two structured questionnaires, 19 children with ASD reported difficulties with social skills including social engagement and temper management and also reported difficulties with social competence, affecting both friendships and peer relationships. Parents rated the children's social skill and competence as significantly worse than did the children themselves, but there was considerable agreement about the areas that were problematic. Using an informal measure to highlight their children's difficulties, parents raised issues relating to conversation skills, social emotional reciprocity and peer relationships. The implications for assessment and intervention are discussed.

Influence of birth weight on gene regulators of lipid metabolism and utilization in subcutaneous adipose tissue and skeletal muscle of neonatal pigs.

Epidemiological studies suggest that low-birth weight infants show poor neonatal growth and increased susceptibility to metabolic syndrome, in particular, obesity and diabetes. Adipose tissue development is regulated by many genes, including members of the peroxisome proliferator-activated receptor (PPAR) and the fatty acid-binding protein (FABP) families. The aim of this study was to determine the influence of birth weight on key adipose and skeletal muscle tissue regulating genes. Piglets from 11 litters were ranked according to birth weight and 3 from each litter assigned to small, normal, or large-birth weight groups. Tissue samples were collected on day 7 or 14. Plasma metabolite concentrations and the expression of PPARG2, PPARA, FABP3, and FABP4 genes were determined in subcutaneous adipose tissue and skeletal muscle. Adipocyte number and area were determined histologically. Expression of FABP3 and 4 was significantly reduced in small and large, compared with normal, piglets in adipose tissue on day 7 and in skeletal muscle on day 14. On day 7, PPARA and PPARG2 were significantly reduced in adipose tissue from small and large piglets. Adipose tissue from small piglets contained more adipocytes than normal or large piglets. Birth weight had no effect on adipose tissue and skeletal muscle lipid content. Low-birth weight is associated with tissue-specific and time-dependent effects on lipid-regulating genes as well as morphological changes in adipose tissue. It remains to be seen whether these developmental changes alter an individual's susceptibility to metabolic syndrome.

Arcanobacterium hippocoleae sp. nov., from the vagina of a horse

A polyphasic taxonomic study was performed on a previously unidentified gram-positive, facultatively anaerobic, diphtheroid-shaped organism isolated from a vaginal discharge of a horse. Comparative 16S rRNA gene sequencing demonstrated that the strain was a member of the genus Arcanobacterium, but sequence divergence values of >4% with described species of this genus (viz: Arcanobacterium haemolyticum, Arcanobacterium bernardiae, Arcanobacterium phocae, Arcanobacterium pluranimalium and Arcanobacterium pyogenes) demonstrated that the isolate represented a novel species. The unknown bacterium was readily distinguished from other Arcanobacterium species by biochemical tests. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Arcanobacterium hippocoleae sp. nov. The type strain of A. hippocoleae is CCUG 44697T (= CIP 106850T).

A robust hybrid feedback active noise cancellation headset

This paper investigates the robustness of a hybrid analog/digital feedback active noise cancellation (ANC) headset system. The digital ANC systems with the filtered-x least-mean-square (FXLMS) algorithm require accurate estimation of the secondary path for the stability and convergence of the algorithm. This demands a great challenge for the ANC headset design because the secondary path may fluctuate dramatically such as when the user adjusts the position of the ear-cup. In this paper, we analytically show that adding an analog feedback loop into the digital ANC systems can effectively reduce the plant fluctuation, thus achieving a more robust system. The method for designing the analog controller is highlighted. A practical hybrid analog/digital feedback ANC headset has been built and used to conduct experiments, and the experimental results show that the hybrid headset system is more robust under large plant fluctuation, and has achieved satisfactory noise cancellation for both narrowband and broadband noises.

Pseudomonas syringae pv. phaseolicola: from ‘has bean’ to supermodel

Pseudomonas syringae pv. phaseolicola causes halo blight of the common bean, Phaseolus vulgaris, worldwide and remains difficult to control. Races of the pathogen cause either disease symptoms or a resistant hypersensitive response on a series of differentially reacting bean cultivars. The molecular genetics of the interaction between P. syringae pv. phaseolicola and bean, and the evolution of bacterial virulence, have been investigated in depth and this research has led to important discoveries in the field of plant-microbe interactions. In this review, we discuss several of the areas of study that chart the rise of P. syringae pv. phaseolicola from a common pathogen of bean plants to a molecular plant-pathogen supermodel bacterium. Taxonomy: Bacteria; Proteobacteria, gamma subdivision; order Pseudomonadales; family Pseudomonadaceae; genus Pseudomonas; species Pseudomonas syringae; Genomospecies 2; pathogenic variety phaseolicola. Microbiological properties: Gram-negative, aerobic, motile, rod-shaped, 1.5 µm long, 0.7-1.2 µm in diameter, at least one polar flagellum, optimal temperatures for growth of 25-30 °C, oxidase negative, arginine dihydrolase negative, levan positive and elicits the hypersensitive response on tobacco. Host range: Major bacterial disease of common bean (Phaseolus vulgaris) in temperate regions and above medium altitudes in the tropics. Natural infections have been recorded on several other legume species, including all members of the tribe Phaseoleae with the exception of Desmodium spp. and Pisum sativum. Disease symptoms: Water-soaked lesions on leaves, pods, stems or petioles, that quickly develop greenish-yellow haloes on leaves at temperatures of less than 23 °C. Infected seeds may be symptomless, or have wrinkled or buttery-yellow patches on the seed coat. Seedling infection is recognized by general chlorosis, stunting and distortion of growth. Epidemiology: Seed borne and disseminated from exudation by water-splash and wind occurring during rainfall. Bacteria invade through wounds and natural openings (notably stomata). Weedy and cultivated alternative hosts may also harbour the bacterium. Disease control: Some measure of control is achieved with copper formulations and streptomycin. Pathogen-free seed and resistant cultivars are recommended. Useful websites: Pseudomonas-plant interaction http://www.pseudomonas-syringae.org/; PseudoDB http://xbase.bham.ac.uk/pseudodb/; Plant Associated and Environmental Microbes Database (PAMDB) http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl; PseudoMLSA Database http://www.uib.es/microbiologiaBD/Welcome.html.