4,615 research outputs found

    The Host Galaxy of GRB980703 at Radio Wavelengths - a Nuclear Starburst in a ULIRG

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    We present radio observations of GRB980703 at 1.43, 4.86, and 8.46 GHz for the period of 350 to 1000 days after the burst. These radio data clearly indicate that there is a persistent source at the position of GRB980703 with a flux density of approximately 70 μ\muJy at 1.43 GHz, and a spectral index, β0.32\beta\approx 0.32, where FννβF_\nu\propto \nu^{-\beta}. We show that emission from the afterglow of GRB980703 is expected to be one to two orders of magnitude fainter, and therefore cannot account for these observations. We interpret this persistent emission as coming from the host galaxy --- the first example of a gamma-ray burst (GRB) host detection at radio wavelengths. We show that emission from an AGN is unlikely, and find that it can be explained as a result of a star-formation rate (SFR) of massive stars (M>5M_\odot) of 90 M_\odot/yr, which gives a total SFR of 500\approx 500 M_\odot/yr. Using the correlation between the radio and far-IR (FIR) luminosities of star-forming galaxies, we find that the host of GRB980703 is at the faint end of the class of Ultra Luminous Infrared Galaxies (ULIRGs), with L_{FIR}\sim few\times 10^{12} L_\odot. From the radio measurements of the offset between the burst and the host, and the size of the host, we conclude that GRB980703 occurred near the center of the galaxy in a region of maximum star formation. A comparison of the properties of this galaxy with radio and optical surveys at a similar redshift (z1z\approx 1) reveals that the host of GRB980703 is an average star-forming galaxy. This result has significant implications for the potential use of a GRB-selected galaxy sample for the study of galaxies and the IGM at high redshifts.Comment: Submitted to Ap

    Gamma-ray bursts and X-ray melting of material as a potential source of chondrules and planets

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    The intense radiation from a gamma-ray burst (GRB) is shown to be capable of melting stony material at distances up to 300 light years which subsequently cool to form chondrules. These conditions were created in the laboratory for the first time when millimeter sized pellets were placed in a vacuum chamber in the white synchrotron beam at the European Synchrotron Radiation Facility (ESRF). The pellets were rapidly heated in the X-ray and gamma-ray furnace to above 1400 C melted and cooled. This process heats from the inside unlike normal furnaces. The melted spherical samples were examined with a range of techniques and found to have microstructural properties similar to the chondrules that come from meteorites. This experiment demonstrates that GRBs can melt precursor material to form chondrules that may subsequently influence the formation of planets. This work extends the field of laboratory astrophysics to include high power synchrotron sources.Comment: 8 pages, 10 figures. Proceedings of the 5th INTEGRAL Workshop, Munich 16-20 February 2004. High resolution figures available at http://bermuda.ucd.ie/%7Esmcbreen/papers/duggan_01.pd

    The pre-WDVV ring of physics and its topology

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    We show how a simplicial complex arising from the WDVV (Witten-Dijkgraaf-Verlinde-Verlinde) equations of string theory is the Whitehouse complex. Using discrete Morse theory, we give an elementary proof that the Whitehouse complex Δn\Delta_n is homotopy equivalent to a wedge of (n2)!(n-2)! spheres of dimension n4n-4. We also verify the Cohen-Macaulay property. Additionally, recurrences are given for the face enumeration of the complex and the Hilbert series of the associated pre-WDVV ring.Comment: 13 pages, 4 figures, 2 table

    New Pedagogical Models Facilitated by Technology

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    This paper discusses the outcome of research conducted to assess the effectiveness of Work-Based Learning (WBL) from the perspective of stakeholders. WBL has increasingly become an area of interest for the higher education (HE) sector. It can support the personal and professional development of students who are already in work. The focus of the learning and development tends to be on the student’s workplace activities. Previous research has mainly considered only two stakeholder contexts, namely the learner and the academic institution. The significance of the study stems from extending the stakeholder contexts to include the employer and the professional body. The aim of this study was to assess the effectiveness of delivery of WBL from the perspective of a range of stakeholders including students, programme leaders (PLs), tutors, university support services, employers and representatives of professional bodies. Case study research methodology was adapted with mixed method research techniques for data capture and analysis using both qualitative and quantitative approaches. The study examined five (5) WBL programmes at Northumbria University in the UK. The three most influential factors in the effectiveness of WBL were found to be: quality, access and support. The contribution to new knowledge in WBL research is through a “Four-Pillar model” which has been developed to reflect the stakeholder contexts. Consideration of this model helps ensure WBL programmes cater for the current demands from the labour market. The findings of this study include factors which facilitate and/or obstruct the effective implementation of WBL programmes whilst identifying feasible strategies to overcome those challenges and share them with all stakeholders of WBL. Recommendations are made on resolving the identified issues and to extend and improve the effectiveness of WBL. Finally this paper looks at how these results could apply to encourage WBL uptake in a third world developing country like Sri Lanka where you are starting from a zero base. Sri Lanka is yet to embark on WBL formally although online distance learning is more of a reality

    Relationship between pig carcass tail lesions and lung lesions

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    Tail biting is common on farms that are more prone to disease. Tail lesions can be associated with poor health either directly by providing a route of entry for pathogens or indirectly as conditions which trigger tail biting may also affect pig health. The aim of this study was to investigate the relationship between carcass tail lesion and lung lesion severity scores in Irish slaughter pigs. Factory visits occurred over 5 days (Jan – March 2015) and tail lesion score (0 – 4) according to severity, sex, and kill number was recorded for every pig after scalding and dehairing. The lungs from each carcass were scored for lesions using an adapted version of the BPEX pig health scheme. Presence of pleuropneumonia (APP), abscesses and pyaemia was recorded. The severity of enzootic pneumonia (EP-like lesions) was recorded on a scale of 0 – 50 and grouped into none/ mild (score 0 – 10), moderate (score 11 – 20) and severe (score 21 – 50). Severity of pleurisy was scored on a 0 – 2 scale with a separate variable for lungs that were attached to the chest wall (score 2). These lungs could not be assessed for other lung lesions and therefore a separate database was created for assessing the pleurisy lesions (n = 5,628) while the final database contained animals (n = 4,491) with records for tail lesions, EP-like lesion scores and pleurisy (level 0 + 1). Associations between tail lesions and sex and the different lung lesion outcomes were analysed using generalized linear mixed models (PROC GLIMMIX) with random effect for batch. EP-like lesions and pleurisy were the most common lesions, though large variation existed between batches. Pigs with severe tail lesions tended to have more severe pleurisy where the lungs remained attached to the chest wall than pigs with moderate tail lesions. No other associations between tail lesion scores and lung lesions were found. Although tail lesions on the carcass may not be an accurate predictor of lung health, tail lesions are important welfare indicators and respiratory disease is among the most significant infectious conditions affecting pigs. Thus, recording of tail and lung lesions at meat inspection provides valuable information regarding the on-farm health welfare of pigs

    Pig producer perspectives on the use of meat inspection as an animal health and welfare diagnostic tool in the Republic of Ireland and Northern Ireland

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    peer-reviewedBackground Currently, there is growing interest in developing ante and post mortem meat inspection (MI) to incorporate measures of pig health and welfare for use as a diagnostic tool on pig farms. However, the success of the development of the MI process requires stakeholder engagement with the process. Knowledge gaps and issues of trust can undermine the effective exchange and utilisation of information across the supply chain. A social science research methodology was employed to establish stakeholder perspectives towards the development of MI to include measures of pig health and welfare. In this paper the findings of semi-structured telephone interviews with 18 pig producers from the Republic of Ireland and Northern Ireland are presented. Results Producers recognised the benefit of the utilisation of MI data as a health and welfare diagnostic tool. This acknowledgment, however, was undermined for some by dissatisfaction with the current system of MI information feedback, by trust and fairness concerns, and by concerns regarding the extent to which data would be used in the producers’ interests. Tolerance of certain animal welfare issues may also have a negative impact on how producers viewed the potential of MI data. The private veterinary practitioner was viewed as playing a vital role in assisting them with the interpretation of MI data for herd health planning. Conclusions The development of positive relationships based on trust, commitment and satisfaction across the supply chain may help build a positive environment for the effective utilisation of MI data in improving pig health and welfare. The utilisation of MI as a diagnostic tool would benefit from the development of a communication strategy aimed at building positive relationships between stakeholders in the pig industry.The authors acknowledge the financial support provided by the Irish Government’s National Development Plan 2007–2013 (Department of Agriculture, Food and the Marine’s Competitive Research Programme – RSF 11/S/107)

    Exploring the role of professional associations in collective learning in London and New York's advertising and law professional service firm clusters.

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    The value of regional economies for collective learning has been reported by numerous scholars. However often work has been criticised for lacking analytical clarity and failing to explore the architectures of collective learning and the role of the knowledge produced in making firms in a cluster economy successful. This paper engages with these problematics and investigates how collective learning is facilitated in the advertising and law professional service firm clusters in London and New York. It explores the role of professional associations and investigates how they mediate a collective learning process in each city. It argues that professional associations seed urban communities of practice that emerge outside of the formal activities of professional associations. In these communities individual with shared interests in advertising and law learn from one-another and are therefore able to adapt and evolve one-another approaches to common industry challenges. The paper suggests this is another form of the variation Marshall highlighted in relation to cluster-based collective learning. The paper also shows how the collective learning process is affected by the presence, absence and strength of an institutional thickness. It is therefore argued that a richer understanding of institutional affects is needed in relation to CL

    Skunk and Raccoon Rabies in the Eastern United States: Temporal and Spatial Analysis

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    Since 1981, an epizootic of raccoon rabies has spread throughout the eastern United States. A concomitant increase in reported rabies cases in skunks has raised concerns that an independent maintenance cycle of rabies virus in skunks could become established, affecting current strategies of wildlife rabies control programs. Rabies surveillance data from 1981 through 2000 obtained from the health departments of 11 eastern states were used to analyze temporal and spatial characteristics of rabies epizootics in each species. Spatial analysis indicated that epizootics in raccoons and skunks moved in a similar direction from 1990 to 2000. Temporal regression analysis showed that the number of rabid raccoons predicted the number of rabid skunks through time, with a 1-month lag. In areas where the raccoon rabies virus variant is enzootic, spatio-temporal analysis does not provide evidence that this rabies virus variant is currently cycling independently among skunks

    Development of a GIS-based, real-time Internet mapping tool for rabies surveillance

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    BACKGROUND: Oral rabies vaccination programs have been implemented to control the spread of wildlife rabies in the United States. However, current surveillance systems are inadequate for the efficient management and evaluation of these large scale vaccine baiting programs. With this in mind, a GIS-based rabies surveillance database and Internet mapping application was created. This surveillance system, RabID, provides a new resource for the rapid mapping and dissemination of data on animal rabies cases in relation to unaffected, enzootic, and baited areas where current interventions are underway. RESULTS: RabID is a centralized database for diagnostic and demographic information collected by local, state, and federal agencies involved in rabies surveillance. The geo-referenced database remits data to an Internet-accessible mapping application that displays rabies surveillance data in relation to environmental and geographic features. CONCLUSION: RabID provides a pioneering example of the power of geographically based Internet-accessible, infectious disease surveillance. This surveillance system was developed from existing technology and is readily adaptable to other infectious diseases and may be particularly useful for zoonoses. The development and application of public health informatics technology may enhance the effectiveness of public health interventions and allow better evaluation of public health interventions
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