3,733 research outputs found

    Monitoring LMXBs with the Faulkes Telescopes

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    We have been undertaking a monitoring project of 13 low-mass X-ray binaries (LMXBs) using FT North since early 2006. The introduction of FT South has allowed us to extend this monitoring to include 15 southern hemisphere LMXBs. With new instrumentation, we also intend to expand this monitoring to include both infrared wavelengths and spectroscopy.Comment: Conference proceedings from 'A Population Explosion: The Nature and Evolution of X-ray Binaries in Diverse Environments', 28 Oct - 2 Nov, St. Petersburg Beach, FL. 3 pages, 3 figure

    Prayer and psychological health: a study among sixth-form pupils attending Catholic and Protestant schools in Northern Ireland

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    Eysenck's dimensional model of personality includes two indicators of psychological health, defined as neuroticism and psychoticism. In order to examine the association between psychological health and prayer, two samples of sixth-form pupils in Northern Ireland (16- to 18-year-olds) attending Catholic (N = 1246) and Protestant (N = 1060) schools completed the abbreviated Revised Eysenck Personality Questionnaire alongside a simple measure of prayer frequency. The data demonstrated a positive association between prayer frequency and better levels of psychological health as assessed by Eysenck's notion of psychoticism. Among pupils attending both Catholic and Protestant schools, higher levels of prayer were associated with lower psychoticism scores. Among pupils attending Catholic schools, however, higher levels of prayer were also associated with higher neuroticism scores

    Clinical trials and basic research: defining mechanisms and improving treatment in connective tissue disease

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    Despite advances in elucidating the pathogenic factors responsible for its development, systemic sclerosis remains complex and poorly understood, and treatment options are limited. Multidisciplinary collaborative efforts are needed to better characterize clinical and prognostic parameters and to design and implement large-scale clinical trials in well defined populations with therapies that target potential disease modulators

    Systemic sclerosis and related connective tissue diseases: present and future

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    Greece, to discuss systemic sclerosis (SSc) and related connective tissue diseases (CTDs). SSc is a clinically heterogeneous and complex disease that is characterized by vascular dysfunction, vascular and extravascular fibrosis, and characteristic immune derangements, and for which few treatment options are available. The aims of the CTD International Scientific Advisory Board were threefold: to define the role of local mediators in CTDs, in particular to identify the nature of the initial insult in CTDs and to consider the role of genetic perturbations in CTDs; to translate what has been learned from clinical trials into clinical practice and to evaluate current treatment options for CTDs and their complications; and to address future directions for the management of CTDs and associated rare diseases, based on the biologic mechanisms elucidated. This supplemen

    Expression profiles of nestin and synemin in reactive astrocytes and Müller cells following retinal injury: a comparison with glial fibrillar acidic protein and vimentin

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    Purpose: To examine the expression patterns of the intermediate filament (IF) proteins nestin and synemin following retinal injury. Methods: Wide-scale retinal injuries were created by experimental retinal detachment of 1, 3, 7, or 30 days\u27 duration. Injuries were induced in the right eyes of Long Evans rats, while the left eyes served as internal controls. Vibratome sections of control and injured retinas were labeled with fluorescent probes using a combination of anti-glial fibrillary acidic protein, -vimentin, -nestin, -synemin, -bromodeoxyuridine, and the lectin probe, isolectin B4. Additionally, antibody specificity, as well as protein and mRNA levels of nestin and synemin were determined and quantified using standard western blotting and real time polymerase chain reaction (RT-PCR) techniques. Results: Immunocytochemistry showed increased Müller cell labeling at 1, 3, and 7 days post injury for all four IFs, although the relative levels of nestin expression varied dramatically between individual Müller cells. Nestin was consistently observed in the foremost processes of those Müller cells that grew into the subretinal space, forming glial scars. Elevated levels of nestin expression were also observed in bromodeoxyuridine-labeled Müller cells following retinal insult. Quantitative polymerase chain reaction (qPCR) showed a twofold increase in nestin mRNA 1 day after injury, a level maintained at 3 and 7 days. Western blotting using anti-nestin showed a single band at 220 kDa and the intensity of this band increased following injury. Anti-synemin labeling of control retinas revealed faint labeling of astrocytes; this increased after injury, demonstrating an association with blood vessels. Additionally, there was an upregulation of synemin in Müller cells. qPCR and western blotting with anti-synemin showed a continuous increase in both gene and protein expression over time. Conclusions: Retinal injury induces an upregulation of a complement of four intermediate filament proteins, including synemin and nestin, in Müller cells. The latter provides suggestive support for the concept that these cells may revert to a more developmentally immature state, since these two IF proteins are developmentally regulated and expressed, and thus may serve as cell cycle reentry markers. Nestin and its differential expression patterns with glial fibrillary acidic protein and vimentin networks, as well as its association with proliferating Müller cells and those extending into the subretinal space, suggest a significant role of this protein in glial scar formation and perhaps gliogenesis. Synemin immunopositive astrocytes demonstrate a close relationship to the retinal vasculature, and illustrate a remarkable ability to reorganize their morphology in response to injury. Further examination of the changes in the cytoskeletal signatures of both of these glial cell types may lead to a more comprehensive understanding of mechanisms underway following retinal and other central nervous system injuries. © 2010 Molecular Vision

    The Jacobi orientation and the two-variable elliptic genus

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    We explain the relationship between the sigma orientation and Witten genus on the one hand and the two-variable elliptic genus on the other. We show that if E is an elliptic spectrum, then the Theorem of the Cube implies the existence of canonical SU-orientation of the associated spectrum of Jacobi forms. In the case of the elliptic spectrum associated to the Tate curve, this gives the two-variable elliptic genus. We also show that the two-variable genus arises as an instance of the circle-equivariant sigma orientation.Comment: Revised to better exhibit complex orientation of MSU^(CP^\infty_{-infty}

    Reconstructing the primordial power spectrum from the CMB

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    We propose a straightforward and model independent methodology for characterizing the sensitivity of CMB and other experiments to wiggles, irregularities, and features in the primordial power spectrum. Assuming that the primordial cosmological perturbations are adiabatic, we present a function space generalization of the usual Fisher matrix formalism, applied to a CMB experiment resembling Planck with and without ancillary data. This work is closely related to other work on recovering the inflationary potential and exploring specific models of non-minimal, or perhaps baroque, primordial power spectra. The approach adopted here, however, most directly expresses what the data is really telling us. We explore in detail the structure of the available information and quantify exactly what features can be reconstructed and at what statistical significance.Comment: 43 pages Revtex, 23 figure

    Investigation of pulsed laser induced dewetting in nanoscopic metal films

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    Hydrodynamic pattern formation (PF) and dewetting resulting from pulsed laser induced melting of nanoscopic metal films have been used to create spatially ordered metal nanoparticle arrays with monomodal size distribution on SiO_{\text{2}}/Si substrates. PF was investigated for film thickness h\leq7 nm < laser absorption depth \sim11 nm and different sets of laser parameters, including energy density E and the irradiation time, as measured by the number of pulses n. PF was only observed to occur for E\geq E_{m}, where E_{m} denotes the h-dependent threshold energy required to melt the film. Even at such small length scales, theoretical predictions for E_{m} obtained from a continuum-level lumped parameter heat transfer model for the film temperature, coupled with the 1-D transient heat equation for the substrate phase, were consistent with experimental observations provided that the thickness dependence of the reflectivity of the metal-substrate bilayer was incorporated into the analysis. The spacing between the nanoparticles and the particle diameter were found to increase as h^{2} and h^{5/3} respectively, which is consistent with the predictions of the thin film hydrodynamic (TFH) dewetting theory. These results suggest that fast thermal processing can lead to novel pattern formation, including quenching of a wide range of length scales and morphologies.Comment: 36 pages, 11 figures, 1 tabl

    Diagnosing Crohn\u27s Disease: An economic analysis comparing wireless capsule endoscopy with traditional diagnostic procedures

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    The purpose of this study was to review economic considerations related to establishing a diagnosis of Crohn\u27s disease, and to compare the costs of a diagnostic algorithm incorporating wireless capsule endoscopy (WCE) with the current algorithm for diagnosing Crohn\u27s disease suspected in the small bowel. Published literature, clinical trial data on WCE in comparison to other diagnostic tools, and input from clinical experts were used as data sources for (1) identifying contributors to the costs of diagnosing Crohn\u27s disease; (2) exploring where WCE should be placed within the diagnostic algorithm for Crohn\u27s; and (3) constructing decision tree models with sensitivity analyses to explore costs (from a payor perspective) of diagnosing Crohn\u27s disease using WCE compared to other diagnostic methods. Literature review confirms that Crohn\u27s disease is a significant and growing public health concern from clinical, humanistic and economic perspectives, and results in a long-term burden for patients, their families, providers, insurers, and employers. Common diagnostic procedures include radiologic studies such as small bowel follow through (SBFT), enteroclysis, CT scans, ultrasounds, and MRIs, as well as serologic testing, and various forms of endoscopy. Diagnostic costs for Crohn\u27s disease can be considerable, especially given the cycle of repeat testing due to the low diagnostic yield of certain procedures and the inability of current diagnostic procedures to image the entire small bowel. WCE has a higher average diagnostic yield than comparative procedures due to imaging clarity and the ability to visualize the entire small bowel. Literature review found the average diagnostic yield of SBFT and colonoscopy for work-up of Crohn\u27s disease to be 53.87%, whereas WCE had a diagnostic yield of 69.59%. A simple decision tree model comparing two arms--colonoscopy and SBFT, or WCE--estimates that WCE produces a cost savings of 291dollars for each case presenting for diagnostic work-up for Crohn\u27s. Sensitivity analysis varying diagnostic yields of colonoscopy and SBFT vs. WCE demonstrates that WCE is still less costly than SBFT and colonoscopy even at their highest reported yields, as long as the diagnostic yield of WCE is 64.10% or better. Employing WCE as a first-line diagnostic procedure appears to be less costly, from a payor perspective, than current common procedures for diagnosing suspected Crohn\u27s disease in the small bowel. Although not addressed in this model, earlier diagnosis with WCE (due to higher diagnostic yield) also could lead to earlier management, improved quality of life and workplace productivity for people with Crohn\u27s disease

    Novel functional hepatitis C virus glycoprotein isolates identified using an optimised viral pseudotype entry assay

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    Retrovirus pseudotypes are a highly tractable model used to study the entry pathways of enveloped viruses. This model has been extensively applied to the study of the hepatitis C virus (HCV) entry pathway, pre-clinical screening of antiviral antibodies and for assessing the phenotype of patient-derived viruses using HCV pseudoparticles (HCVpp) possessing the HCV E1 and E2 glycoproteins. However, not all patient-isolated clones produce particles that are infectious in this model. This study investigated factors that might limit phenotyping of patient-isolated HCV glycoproteins. Genetically related HCV glycoproteins from individual patient quasispecies were discovered to behave very differently in this entry model. Empirical optimisation of the ratio of packaging construct and glycoprotein-encoding plasmid was required for successful HCVpp genesis for different clones. The selection of retroviral packaging construct also influenced the function of HCV pseudoparticles. Some glycoprotein constructs tolerated a wide range of assay parameters, while others were much more sensitive to alterations. Furthermore, glycoproteins previously characterised as unable to mediate entry were found to be functional. These findings were validated using chimeric cell-cultured HCV bearing these glycoproteins. Using the same empirical approach we demonstrated that generation of infectious ebolavirus pseudoviruses (EBOVpv) were also sensitive to the amount, and ratio, of plasmids used, and that protocols for optimal production of these pseudoviruses is dependent on the exact virus glycoprotein construct. These findings demonstrate that it is crucial for studies utilising pseudoviruses to conduct empirical optimisation of pseudotype production for each specific glycoprotein sequence to achieve optimal titres and facilitate accurate phenotyping
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