3,278 research outputs found

    Post-metamorphic fluid infiltration into granulites from the Adirondack Mountains, USA

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    Post-metamorphic effects in the anorthosites of the Adirondacks, New York were described. Calcite-chlorite-sericite assemblages occur as veins, in disseminated form and as clots, and document retrograde fluid infiltration. These features are associated with late-state CO2-rich fluid inclusions. Stable isotope analyses of calcites indicates that the retrograde fluids interacted with meta-igneous and supracrustal lithologies, but the precise timing of the retrogression is as yet unknown

    Exactly Conservative Integrators

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    Traditional numerical discretizations of conservative systems generically yield an artificial secular drift of any nonlinear invariants. In this work we present an explicit nontraditional algorithm that exactly conserves these invariants. We illustrate the general method by applying it to the three-wave truncation of the Euler equations, the Lotka--Volterra predator--prey model, and the Kepler problem. This method is discussed in the context of symplectic (phase space conserving) integration methods as well as nonsymplectic conservative methods. We comment on the application of our method to general conservative systems.Comment: 30 pages, postscript (1.3MB). Submitted to SIAM J. Sci. Comput

    Reloading the Armalite? Victims and Targets of Violent Dissident Irish Republicanism 2007-2015

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    The centenary of the 1916 Rising marks a time of peaceful commemoration, across the island of Ireland. However, several violent dissident republican groups wish to seize it as an opportunity to re-organise in an attempt to bolster and legitimise their sustained paramilitary campaign. This study seeks to provide a greater understanding, of how this paramilitary activity has manifested from 2007 to mid-2015. We do this by assessing target selection, through analysis of the Violent Dissident Republican (VDR) events database. The data suggest that civilian targets are the most regularly attacked. However, when exclusively analysing targets of detonated explosives, the data show that police, security personnel and their infrastructure are more consistently targeted. The target selected can and does have an effect on attack method. These findings can both assist in protecting the potential targets of VDR attacks and contribute to the development of a strong nationalised, and localised, counter VDR narrative

    Here to Stay? The Rising Threat of Violent Dissident Republicanism in Northern Ireland

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    Since the advent of the Good Friday peace agreement, violence associated with dissident Irish Republican groups continues to present major security challenges. While there has not been a tragedy on the scale of the 1998 Omagh bombing, the level of violent dissident Republican (VDR) activity has risen steadily in frequency since then, and in 2010 reached unprecedented levels. This article presents findings from the VDR Project at the International Center for the Study of Terrorism at Pennsylvania State University. The research is based on the extensive identification, collection, and analysis of open source material examining the nature and extent of VDR activity from 1997 to 2010. The project analyses data on VDR activity across this period as well as the individuals taking part in these violent events. The data suggests that while originally recruitment was predominantly southern based it is now more focused on Northern Ireland. Analysis of the data also indicates that the VDR leadership continues to recruit individuals with skill-sets to serve the movement's aims

    The cytochrome P450 family in the parasitic nematode <i>Haemonchus contortus</i>

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    &lt;i&gt;Haemonchus contortus&lt;/i&gt;, a highly pathogenic and economically important parasitic nematode of sheep, is particularly adept at developing resistance to the anthelmintic drugs used in its treatment and control. The basis of anthelmintic resistance is poorly understood for many commonly used drugs with most research being focused on mechanisms involving drug targets or drug efflux. Altered or increased drug metabolism is a possible mechanism that has yet to receive much attention despite the clear role of xenobiotic metabolism in pesticide resistance in insects. The cytochrome P450s (CYPs) are a large family of drug-metabolising enzymes present in almost all living organisms, but for many years thought to be absent from parasitic nematodes. In this paper, we describe the CYP sequences encoded in the &lt;i&gt;H. Contortus&lt;/i&gt; genome and compare their expression in different parasite life-stages, sexes and tissues. We developed a novel real-time PCR approach based on partially assembled CYP sequences “tags” and confirmed findings in the subsequent draft genome with RNA-seq. Constitutive expression was highest in larval stages for the majority of CYPs, although higher expression was detected in the adult male or female for a small subset of genes. Many CYPs were expressed in the worm intestine. A number of &lt;i&gt;H. Contortus&lt;/i&gt; genes share high identity with &lt;i&gt;Caenorhabditis elegans&lt;/i&gt; CYPs and the similarity in their expression profiles supports their classification as putative orthologues. Notably, &lt;i&gt;H. Contortus&lt;/i&gt; appears to lack the dramatic CYP subfamily expansions seen in &lt;i&gt;C. elegans&lt;/i&gt; and other species, which are typical of CYPs with exogenous roles. However, a small group of &lt;i&gt;H. Contortus&lt;/i&gt; genes cluster with the &lt;i&gt;C. elegans&lt;/i&gt; CYP34 and CYP35 subfamilies and may represent candidate xenobiotic metabolising genes in the parasite

    Ghrelin in the human myometrium

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    <p>Abstract</p> <p>Background</p> <p>Ghrelin is a 28-amino acid octanolyated peptide, synthesised primarily in the stomach. It stimulates growth hormone release, food intake and exhibits many other diverse effects. Our group have previously determined that ghrelin inhibited human contractility in <it>vitro</it>. The aim of this study therefore, was to investigate the expression of ghrelin, its receptor, the growth hormone secretagogue receptor type 1 (GHS-R1), ghrelin O-acyltransferase (GOAT) which catalyses ghrelin octanoylation, prohormone convertase 1/3 (PC1/3) responsible for pro-ghrelin processing, in human myometrium, during pregnancy prior to labour, during labour and in the non-pregnant state. Modulation of ghrelin and ghrelin receptor expression in cultured myometrial cells was also investigated.</p> <p>Methods</p> <p>mRNA and protein were isolated from human myometrium and the myometrial smooth muscle cell line hTERT-HM; and real-time fluorescence RT-PCR, western blotting and fluorescence microscopy performed. The effects of β-Estradiol and bacterial lipopolysaccharide (LPS) on hTERT-HM gene expression were evaluated by western blotting.</p> <p>Results</p> <p>We have reported for the first time the expression and processing of ghrelin, GHS-R1, GOAT and PC1/3 expression in human myometrium, and also the down-regulation of ghrelin mRNA and protein expression during labour. Furthermore, GHS-R1 protein expression significantly decreased at labour. Myometrial GOAT expression significantly increased during term non-labouring pregnancy in comparison to both non-pregnant and labouring myometrium. Mature PC1/3 protein expression was significantly decreased at term pregnancy and labour in comparison to non-pregnant myometrium. Ghrelin, GHS-R1, GOAT and PC1/3 mRNA and protein expression was also detected in the hTERT-HM cells. Ghrelin protein expression decreased upon LPS treatment in these cells while β-Estradiol treatment increased GHS-R1 expression.</p> <p>Conclusions</p> <p>Ghrelin processing occurred in the human myometrium at term pregnancy and in the non-pregnant state. GOAT expression which increased during term non-labouring pregnancy demonstrating a similar expression pattern to prepro-ghrelin and GHS-R1, decreased at labour, signifying possible myometrial ghrelin acylation. Moreover, the presence of PC1/3 may contribute to pro-ghrelin processing. These results along with the previous <it>in vitro </it>data suggest that myometrially-produced and processed ghrelin plays a significant autocrine or paracrine role in the maintenance of relaxation in this tissue during pregnancy. Furthermore, the significant uterine modulators LPS and β-Estradiol are involved in the regulation of ghrelin and ghrelin receptor expression respectively, in the human myometrium.</p

    Charles W. Bennett\u27s The Purchase of the von Ranke Library. A Prefatory Note

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    This article tells the story of Charles Wesley Bennett, who on behalf of Syracuse University purchased the Leopold von Ranke library in 1887. Some important details of the event had recently been uncovered through the discovery of an address Bennett had written for the dedication of the von Ranke Library, which was delivered posthumously (see Additional Information to locate this address)

    Effects of thrombin, PAR-1 activating peptide and a PAR-1 antagonist on umbilical artery resistance in vitro

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    BACKGROUND: The non-thrombotic effects of thrombin in cardiovascular tissues, as mediated via the protease activated receptors (PARs), and particularly PAR-1, have been the focus of much recent research. The aims of this study were to evaluate the effects of thrombin, a specific PAR-1 activating peptide (PAR1-AP), and a PAR-1 antagonist on human umbilical artery tone in vitro. METHODS: Human umbilical artery samples were obtained from 17 women at term. Arterial rings were suspended under physiologic conditions for isometric recording. The in vitro effects of thrombin (0.5 units/mL to 3 units/mL), PAR1-AP TFLLR-NH2 [10(-9) to 10(-6) M], and PAR-1 antagonist (N-trans cinnamoyl- p-fluoroPhe-p-guanidinoPhe-Leu-Arg-Orn-NH2) [10(-9) M to 10(-5) M] on umbilical artery tone were measured. RESULTS: Both thrombin and TFLLR-NH2 exerted a potent cumulative vasodilatory effect on human umbilical artery resistance (P < 0.001). The mean net maximal inhibition (MMI) for thrombin was 53.05% (n = 6; SEM = 1.43) at tissue bath concentration of 3 units/mL. The MMI with TFLLR-NH2 was 61.50 % (n = 6; SEM = 1.43) at bath concentration of 10(-6) M. In comparison to vehicle control, the PAR-1 antagonist did not show a significant relaxant or contractile effect (P > 0.05). CONCLUSION: These findings highlight a potential role for thrombin and PAR-1 receptors in vascular regulation of feto-placental blood flow in normal pregnancy, and in association with the vascular lesions associated with IUGR and pre-eclampsia
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