3,461 research outputs found

    Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock

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    Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations

    Comparative genomic analysis of Mycobacterium avium subspecies obtained from multiple host species

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    <p>Abstract</p> <p>Background</p> <p><it>Mycobacterium avium </it>(<it>M. avium</it>) subspecies vary widely in both pathogenicity and host specificity, but the genetic features contributing to this diversity remain unclear.</p> <p>Results</p> <p>A comparative genomic approach was used to identify large sequence polymorphisms among <it>M. avium </it>subspecies obtained from a variety of host animals. DNA microarrays were used as a platform for comparing mycobacterial isolates with the sequenced bovine isolate <it>M. avium </it>subsp. <it>paratuberculosis </it>(MAP) K-10. Open reading frames (ORFs) were classified as present or divergent based on the relative fluorescent intensities of the experimental samples compared to MAP K-10 DNA. Multiple large polymorphic regions were found in the genomes of MAP isolates obtained from sheep. One of these clusters encodes glycopeptidolipid biosynthesis enzymes which have not previously been identified in MAP. <it>M. avium </it>subsp. <it>silvaticum </it>isolates were observed to have a hybridization profile very similar to yet distinguishable from <it>M. avium </it>subsp. <it>avium</it>. Isolates obtained from cattle (n = 5), birds (n = 4), goats (n = 3), bison (n = 3), and humans (n = 9) were indistinguishable from cattle isolate MAP K-10.</p> <p>Conclusion</p> <p>Genome diversity in <it>M. avium </it>subspecies appears to be mediated by large sequence polymorphisms that are commonly associated with mobile genetic elements. Subspecies and host adapted isolates of <it>M. avium </it>were distinguishable by the presence or absence of specific polymorphisms.</p

    "Outside, it is snowing": Experience and finitude in the nonrepresentational landscapes of Alain Robbe-Grillet

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    Copyright © 2008 PionRomanillos J L, 2008. The definitive, peer-reviewed and edited version of this article is published in Environment and Planning D: Society and Space 26(5) 795 – 822 DOI: 10.1068/d6207This paper presents and explicates the anonymous and impersonal spatialities tentatively mapped in the novels of Alain Robbe-Grillet. Emerging from the kinds of landscapes and visualities articulated, these spatialities are at odds with the kind of anthropocentrism characteristic of phenomenological narratives of spatial experience that would start from an apparently stable human-subject position. It is argued that his body of literature dismantles the anthropocentric narratives and biographies that would produce in both the space of the world and the ‘phenomenological subject’ an unwarranted depth and naturalism. Importantly, and reflecting the theoretical turn towards the being of language, Robbe-Grillet questions the legitimacy of linguistic subjects to capture the spaces of the visible. As such, it is argued that his literature reflects an experience of the critiques of phenomenology. Importantly, this ‘critique’ goes hand in hand with the kinds of spatialities and landscapes that are rendered in the novels—the indefinite perspectives they open up, the paradoxical visualities they sustain or deny, and the disorientation they inject into the heart of spatial experience. These literary effects produce a nonanthropocentric and nonpersonal spatiality which, although contributing to an erasure of the ‘subject’, at the same time expose and open up a sociospatiality based on singularities, intensities, and finitude

    Analgesic effects of intravenous flunixin and intrafunicular lidocaine or their combination for castration of lambs.

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    Abstract Objective: To analyse the effectiveness of intrafunicular lidocaine and intravenous flunixin for reducing pain and signs of stress in lambs undergoing surgical castration. Design: Randomised controlled trial. Setting: One university teaching hospital in Italy. Participants: 30 healthy male lambs, 9-12 weeks old. Intervention: Allocation to five groups: a control group (C), undergoing general anaesthesia but not castration; a surgery group (S), undergoing orchiectomy without analgesic treatment; a surgery-lidocaine group (SL), undergoing orchiectomy and receiving intrafunicular 2 per cent lidocaine solution; a surgery-flunixin group (SF), undergoing orchiectomy and receiving intravenous flunixin; a surgery-flunixin-lidocaine group (SFL), undergoing orchiectomy and receiving both intrafunicular lidocaine and intravenous flunixin. Main outcome measures: Nociception and stress were assessed through intraoperative indicators, serum cortisol concentration, glycaemia, behaviour, immune response and clinical evaluation of the heart rate (HR), respiratory rate and rectal temperature after surgery. Results: Groups S and SL showed increased values of intraoperative HR, mean arterial pressure and postoperative cortisol concentration. In group SFL, cortisol values were similar to those of group C. No other difference could be detected. Conclusions: The combination of intravenous flunixin and intrafunicular lidocaine reduced the pain and discomfort of lambs castrated under general anaesthesia. Intrafunicular lidocaine alone did not prevent pain or discomfort associated with castration

    Laparoscopic Ovariectomy in Standing Mule Mares

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    Mules are hybrids bred from the mating of a jack donkey and a horse mare, known for their strength and resistance and still used to work in agriculture. Although they have been for long considered sterile, evidence of estrus cycle has been demonstrated together with abnormal behavior related to ovarian activity. In this study, a bilateral standing laparoscopic ovariectomy technique using the LigaSure technology was applied in 10 mare mules for treating unwanted behavioral patterns. The technique was effectively performed on these animals avoiding the risk of general anesthesia, and the use of the LigaSure technology allowed good hemostasis and reduced surgical time. Owners declared to be satisfied with the resolution of the behavior

    The Use of a Vaginal Conductivity Probe to Influence Calf Sex Ratio via Altered Insemination Time

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    One hundred eighty-nine mixed breed beef heifers from 13 consignors enrolled in the MACEP heifer development project were utilized in this study. Heifers were synchronized by feeding 0.5 mg melengestrol acetate (MGA) per head per day for 14 days followed by an injection of prostaglandin F2a (PGF2a; 25 mg Lutalyse®) 17 days after the last MGA feeding. Each heifer was fitted with a Heatwatch® transmitter on the morning of PGF2a administration to facilitate detection of estrus. Vaginal conductivity measurements were taken using an Ovatec® probe every 12 hours for 96 hours beginning at the time of PGF2a injection. Heifers randomly assigned to produce a female calf were inseminated near the onset of estrus (as indicated by probe values of £ 55 on the decline). Heifers randomly assigned to produce a male calf were inseminated approximately 24 hours after the onset of estrus (as indicated by probe values of ³ 60 on the incline). All heifers not inseminated by 96 hours after PGF2a were mass inseminated in an attempt to impregnate as many heifers as possible. Heifers that were diagnosed as pregnant as a result of the artificial insemination were subjected to ultrasonography for fetal sex determination. Only 70 of the 189 heifers (37.0%) exhibited estrus according to Heatwatch® and incidence of estrus was influenced by heifer average daily gain, reproductive tract score, and disposition score. Heifers receiving a disposition score of 3 (78.7) had a higher (P\u3c.05) probe reading at AI than those receiving a disposition score of 1 or 2 (70.8 and 72.5, respectively). Heifers with probe readings at insemination of 80 - 84 and \u3e 84 had lower (P\u3c.05) pregnancy rates to AI (13.6 and 0.0%, respectively) than heifers with probe readings in the ranges of \u3c 60, 60 - 64, 65 - 69, 70 - 74, and 75 - 79 (35.7, 40.9, 31.4, 35.3, and 26.9% respectively). Heifers that were bred when probe values were increasing had a lower (P\u3c.05) percentage of male fetuses (34.4%) than those bred during a period of decreasing probe values (69.2% male fetuses). These results demonstrate that a vaginal conductivity probe may be a useful tool to determine an insemination time that could potentially alter calf sex ratio

    Healthy worker survivor analysis in an occupational cohort study of Dutch agricultural workers

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    OBJECTIVES: High microbial exposures in farmers and agricultural workers are associated with less atopy. Although it has been speculated that healthy worker survival could be an explanation, this has not been studied so far. Therefore, we investigated the presence of healthy worker survival in a five-year follow-up study of an occupational cohort of Dutch farmers and agricultural industry (company) workers. METHODS: We compared baseline demographic characteristics, respiratory health, atopy and endotoxin exposure of 259 workers followed up with 124 workers lost to follow-up. Additionally, baseline health status of 31 participants who had changed to lower exposure jobs at follow-up was compared to those with similar or higher exposure jobs at follow-up. RESULTS: In general, no major healthy worker survival effect was found. Nonetheless, small differences were observed between subjects included in follow-up and those lost to follow-up. Those lost to follow-up were older, had a lower peak expiratory flow, and were less often raised on a farm. Company workers lost to follow-up with a farm childhood had more often self-reported allergy, but this was not observed for subjects with atopic sensitization or other respiratory symptoms. No differences were found for any of the studied characteristics in participants with lower exposure at follow-up compared to participants with similar or higher exposure at follow-up. CONCLUSIONS: No major healthy worker survival is present in this organic dust exposed cohort. Differences between participants lost to follow-up and participants included in follow-up with regard to health characteristics are small and unlikely to explain the previously reported inverse associations between endotoxin exposure and atopy

    Residual Stress Determination of Cast Aluminium Benchmark Components Using Strain Relief Techniques

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    Background: Residual stress development in precipitation strengthened aluminium foundry alloys has seen little attention, despite the prevalence of their use over a wide array of applications. Objective: This study aims at the evaluation of the residual stress in a cast aluminium benchmark that develops during precipitation heat treatment and determines the preferable stress relaxing techniques for such applications.Methods: The stress states in the as-cast, T4 and T6 tempers of the same AlSi7Cu0.5Mg (A356 with 0.5 wt% Cu) sample were determined through a novel application of the contour method, standard hole drilling, deep hole drilling and incremental deep hole drilling. Results: The results of all measurement techniques lie within approximately 40 MPa for all regions available for comparison, with the greatest differences occurring between the contour method and deep hole drilling for the T6 component. It is shown that the peak tensile residual stresses are almost identical between the heat-treated components (75 MPa), but the distribution and magnitude of compressive residual stress are found to be significantly different. Conclusions: Among the measurement techniques evaluated, the contour method and incremental hole drilling are found to be more suitable for T6 temper, while all techniques perform equally well for T4 temper due to its relatively low strength. It is hypothesised that the difference between the as-cast and heat-treated samples is due to solution heat treatment and quenching, while the difference in T4 and T6 tempers is attributed to the response to ageing

    Near-infrared interferometric observation of the Herbig Ae star HD144432 with VLTI/AMBER

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    We study the sub-AU-scale circumstellar environment of the Herbig Ae star HD144432 with near-infrared (NIR) VLTI/AMBER observations to investigate the structure of its inner dust disk. The interferometric observations were carried out with the AMBER instrument in the H and K band. We interpret the measured H- and K-band visibilities, the near- and mid-infrared visibilities from the literature, and the SED of HD144432 by using geometric ring models and ring-shaped temperature-gradient disk models with power-law temperature distributions. We derived a K-band ring-fit radius of 0.17 \pm 0.01 AU and an H-band radius of 0.18 \pm 0.01 AU (for a distance of 145 pc). This measured K-band radius of \sim0.17 AU lies in the range between the dust sublimation radius of \sim0.13 AU (predicted for a dust sublimation temperature of 1500 K and gray dust) and the prediction of models including backwarming (\sim0.27 AU). We found that an additional extended halo component is required in both the geometric and temperature-gradient modeling. In the best temperature- gradient model, the disk consists of two components. The inner part of the disk is a thin ring with an inner radius of \sim0.21 AU, a temperature of \sim1600 K, and a ring thickness \sim0.02 AU. The outer part extends from \sim1 AU to \sim10 AU with an inner temperature of \sim400 K. We find that the disk is nearly face-on with an inclination angle of < 28 degree. Our temperature-gradient modeling suggests that the NIR excess is dominated by emission from a narrow, bright rim located at the dust sublimation radius, while an extended halo component contributes \sim6% to the total flux at 2 {\mu}m. The MIR model emission has a two-component structure with \sim20% flux from the inner ring and the rest from the outer part. This two-component structure suggests a disk gap, which is possibly caused by the shadow of a puffed-up inner rim.Comment: 7 pages, 5 figures, accepted by A&
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