5,262 research outputs found

    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

    Q fever through consumption of unpasteurised milk and milk products – a risk profile and exposure assessment

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    Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii which is endemic in cattle, sheep and goats in much of the world, including the United Kingdom (UK). There is some epidemiological evidence that a small proportion of cases in the developed world may arise from consumption of unpasteurised milk with less evidence for milk products such as cheese. Long maturation at low pH may give some inactivation in hard cheese, and viable C. burnetii are rarely detected in unpasteurised cheese compared to unpasteurised milk. Simulations presented here predict that the probability of exposure per person to one or more C. burnetii through the daily cumulative consumption of raw milk in the UK is 04203. For those positive exposures, the average level of exposure predicted is high at 1266 guinea pig intraperitoneal infectious dose 50% units (GP_IP_ID50) per person per day. However, in the absence of human dose–response data, the case is made that the GP_IP_ID50 unit represents a very low risk through the oral route. The available evidence suggests that the risks from C. burnetii through consumption of unpasteurised milk and milk products (including cheese) are not negligible but they are lower in comparison to transmission via inhalation of aerosols from parturient products and livestock contact

    Opening dialogue and fostering collaboration: different ways of knowing in fisheries research

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    We set out to explore some of the impediments which hinder effective communication among fishers, fisheries researchers and managers using detailed ethnographic research amongst commercial handline fishers from two sites- one on the southern Cape coast and the other on the west coast of South Africa. Rather than assuming that the knowledge of fishers and scientists is inherently divergent and incompatible, we discuss an emerging relational approach to working with multiple ways of knowing and suggest that this approach might benefit future collaborative endeavours. Three major themes arising from the ethnographic fieldwork findings are explored: different classifications of species and things; bringing enumerative approaches into dialogue with relational approaches; and the challenge of articulating embodied ways of relating to fish and the sea. Although disconcertments arise when apparently incommensurable approaches are brought into dialogue, we suggest that working with multiple ways of knowing is both productive and indeed necessary in the current South African fisheries research and management contexts. The research findings and discussion on opening dialogue offered in this work suggest a need to rethink contemporary approaches to fisheries research in order to mobilise otherwise stagnant conversations, bringing different ways of knowing into productive conversation

    Why is there no queer international theory?

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    Over the last decade, Queer Studies have become Global Queer Studies, generating significant insights into key international political processes. Yet, the transformation from Queer to Global Queer has left the discipline of International Relations largely unaffected, which begs the question: if Queer Studies has gone global, why has the discipline of International Relations not gone somewhat queer? Or, to put it in Martin Wight’s provocative terms, why is there no Queer International Theory? This article claims that the presumed non-existence of Queer International Theory is an effect of how the discipline of International Relations combines homologization, figuration, and gentrification to code various types of theory as failures in order to manage the conduct of international theorizing in all its forms. This means there are generalizable lessons to be drawn from how the discipline categorizes Queer International Theory out of existence to bring a specific understanding of International Relations into existence

    The applicability of nature-based interventions to support mothers’ postnatal wellbeing: A conceptual review

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    Nature-based interventions represent promising candidates for supporting mothers and infants in the postnatal period, which is a vulnerable time for mothers to experience mental health difficulties. Possible mechanisms by which nature-based interventions may support postnatal health include those of a biological/physiological nature (for example natural light optimising circadian rhythm, improving microbiome health, providing opportunities for physical activity), relational/social pathways, and cognitive and creative pathways. A conceptual understanding of these possible mechanisms will aid the design and evaluation of postnatal nature-based interventions

    Managing Spent Mushroom Compost

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    End of Project ReportThis project addressed how to manage spent mushroom compost (SMC), an issue of critical importance to the continued development of the Irish mushroom industry. The most important aim of the project was to devise a feasible strategy for the management of this material on an industry wide basis. There were two main components of the project, which were conducted in parallel. One analysed the structure of the mushroom industry and the logistics of handling, transporting and processing SMC. The other studied the agronomic properties of SMC in an effort to develop improved guidelines on the best use of SMC in crop production. Our analysis of the SMC management problem led us to conclude that a centralised approach should be taken when developing the solution strategy. The model solution that was formulated is based on the establishment of centrally located depots for SMC collection, temporary storage and possible processing. This approach facilitates a variety of environmentally acceptable SMC end uses ranging from land application to incineration. We examined a variety of possible end uses for SMC, including its use as an alternative fuel. In the immediate future, we believe the predominant end use for SMC will be as an organic manure for field crop production and as a soil conditioner in the landscaping industry. Uses of this type are in line with both Irish and EU legislation regarding waste management. Our analysis suggests that tillage and horticulture offer the best promise for realising the beneficial properties of SMC. We have tested SMC on field crops such as winter and spring wheat and potatoes and on glasshouse crops such as tomatoes. These experiments have shown that SMC increases soil organic matter and improves soil structure. SMC is a very effective source of K and P and also provides trace elements. It makes a contribution to N nutrition but most of the N does not become available to the crop in the first year. For best results therefore, supplementary N must be applied. Overall, our results indicate that SMC can be used with beneficial effects in field crop production. The mushroom industry should move forward with establishing centralised SMC handling facilities to enable the efficient collection, temporary storage, further processing and transportation of SMC to end users. An education and awareness campaign should be conducted amongst farmers, in areas removed from mushroom production, to introduce them to the benefits of SMC and ways to effectively utilise this material.Department of Agriculture, Food and the MarineEuropean Union Structural Funds (EAGGF

    Assay of matrix metalloproteinases types 1, 2, 3 and 9 in breast cancer.

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    Matrix metalloproteinases (MMPs) are zinc dependent endopeptidases implicated in cancer invasion and metastasis. Gelatin zymography was performed on 84 human breast carcinomas and seven normal breast tissues. The precursor form of MMP-2 (72 kDa) was found in 11 (12%) samples, while its two activated forms, i.e. 62 kDa and 59 kDa, were found in three (6%) and 34 (40%) samples respectively. In contrast to MMP-2, most of the samples (52%) contained MMP-9 in its precursor form. Using ELISA, MMP-1 levels were found in 12% of the samples while MMP-3 levels were found in only 2% of the samples. Levels of MMP-2, -3 and -9 correlated inversely with numbers of nodal metastases. Neither MMP-2 nor -9 levels were significantly related to patient outcome. However, patients with high levels of a 50-kDa gelatinase band after zymography had a significantly better survival than patients with low levels. This species was never observed in normal breast tissue

    Playing With Time: Gay Intergenerational Performance Work and the Productive Possibilities of Queer Temporalities

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    This article examines the tendencies of LGBT intergenerational theater projects. By engaging with ideas of queer time, temporal drag, and the pervasive heteronormative imagery of heritability and inheritance, this article explores the possibility that LGBT intergenerational projects may generate some of the problems they aim to challenge. Through the lens of queer time, the article describes the normativity generated in LGBT intergenerational theater projects as a form of restrictive interpellation. The article explores the temporal complexities at play in such theater productions as The Front Room, a specific LGBT intergenerational theater project performed in the United Kingdom in 2011. The article concludes by noting some ways in which intergenerational theater projects might seek to work through the embodiment of the historical quotidian as a mode of resistance to normativity’s recirculation

    The Broad Absorption Line Tidal Disruption Event iPTF15af: Optical and Ultraviolet Evolution

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    We present multi-wavelength observations of the tidal disruption event (TDE) iPTF15af, discovered by the intermediate Palomar Transient Factory (iPTF) survey at redshift z=0.07897z=0.07897. The optical and ultraviolet (UV) light curves of the transient show a slow decay over five months, in agreement with previous optically discovered TDEs. It also has a comparable black-body peak luminosity of Lpeak≈1.5×1044L_{\rm{peak}} \approx 1.5 \times 10^{44} erg/s. The inferred temperature from the optical and UV data shows a value of (3−-5) ×104\times 10^4 K. The transient is not detected in X-rays up to LX<3×1042L_X < 3 \times 10^{42}erg/s within the first five months after discovery. The optical spectra exhibit two distinct broad emission lines in the He II region, and at later times also Hα\alpha emission. Additionally, emission from [N III] and [O III] is detected, likely produced by the Bowen fluorescence effect. UV spectra reveal broad emission and absorption lines associated with high-ionization states of N V, C IV, Si IV, and possibly P V. These features, analogous to those of broad absorption line quasars (BAL QSOs), require an absorber with column densities NH>1023N_{\rm{H}} > 10^{23} cm−2^{-2}. This optically thick gas would also explain the non-detection in soft X-rays. The profile of the absorption lines with the highest column density material at the largest velocity is opposite that of BAL QSOs. We suggest that radiation pressure generated by the TDE flare at early times could have provided the initial acceleration mechanism for this gas. Spectral UV line monitoring of future TDEs could test this proposal.Comment: 20 pages, 12 figures, published in Ap
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