7,886 research outputs found

    Astrophysical SS factor for the 15N(p,γ)16O{}^{15}{\rm N}(p,\gamma){}^{16}{\rm O} reaction from RR-matrix analysis and asymptotic normalization coefficient for 16O15N+p{}^{16}{\rm O} \to {}^{15}{\rm N} + p. Is any fit acceptable?

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    The 15N(p,γ)16O^{15}{\rm N}(p,\gamma)^{16}{\rm O} reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong Jπ=1J^{\pi}=1^{-} resonances at ER=312E_{R}= 312 and 962 keV and direct capture to the ground state. Recently, a new measurement of the astrophysical factor for the 15N(p,γ)16O^{15}{\rm N}(p,\gamma)^{16}{\rm O} reaction has been published [P. J. LeBlanc {\it et al.}, Phys. Rev. {\bf C 82}, 055804 (2010)]. The analysis has been done using the RR-matrix approach with unconstrained variation of all parameters including the asymptotic normalization coefficient (ANC). The best fit has been obtained for the square of the ANC C2=539.2C^{2}= 539.2 fm1{}^{-1}, which exceeds the previously measured value by a factor of 3\approx 3. Here we present a new RR-matrix analysis of the Notre Dame-LUNA data with the fixed within the experimental uncertainties square of the ANC C2=200.34C^{2}=200.34 fm1{}^{-1}. Rather than varying the ANC we add the contribution from a background resonance that effectively takes into account contributions from higher levels. Altogether we present 8 fits, five unconstrained and three constrained. In all the fits the ANC is fixed at the previously determined experimental value C2=200.34C^{2}=200.34 fm1{}^{-1}. For the unconstrained fit with the boundary condition Bc=Sc(E2)B_{c}=S_{c}(E_{2}), where E2E_{2} is the energy of the second level, we get S(0)=39.0±1.1S(0)=39.0 \pm 1.1 keVb and normalized χ~2=1.84{\tilde \chi}^{2}=1.84, i.e. the result which is similar to [P. J. LeBlanc {\it et al.}, Phys. Rev. {\bf C 82}, 055804 (2010)]. From all our fits we get the range 33.1S(0)40.133.1 \leq S(0) \leq 40.1 keVb which overlaps with the result of [P. J. LeBlanc {\it et al.}, Phys. Rev. {\bf C 82}, 055804 (2010)]. We address also physical interpretation of the fitting parameters.Comment: Submitted to PR

    Inter-rater reliability of the Dysexecutive Questionnaire (DEX): comparative data from non-clinician respondents – all raters are not equal

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    Primary objective: The Dysexecutive Questionnaire (DEX) is used to obtain information about executive and emotional problems after neuropathology. The DEX is self-completed by the patient (DEX-S) and an independent rater such as a family member (DEX-I). This study examined the level of inter-rater agreement between either two or three non-clinician raters on the DEX-I in order to establish the reliability of DEX-I ratings. Methods and procedures: Family members and/or carers of 60 people with mixed neuropathology completed the DEX-I. For each patient, DEX-I ratings were obtained from either two or three raters who knew the person well prior to brain injury. Main outcomes and results: We obtained two independent-ratings for 60 patients and three independent-ratings for 36 patients. Intra-class correlations revealed that there was only a modest level of agreement for items, subscale and total DEX scores between raters for their particular family member. Several individual DEX items had low reliability and ratings for the emotion sub-scale had the lowest level of agreement. Conclusions: Independent DEX ratings completed by two or more non-clinician raters show only moderate correlation. Suggestions are made for improving the reliability of DEX-I ratings.</p

    Draft Online Safety Bill. Written evidence submitted by the British and Irish Law, Education and Technology Association (BILETA) (OSB0073)

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    The British and Irish Law Education Technology Association (BILETA) was formed in April 1986 to promote, develop and communicate high-quality research and knowledge on technology law and policy to organisations, governments, professionals, students and the public. BILETA also promotes the use of and research into technology at all stages of education. The present inquiry raises significant questions relating to the proposed Online Safety Regime, the intended regulatory body, and the scope of content within the measures proposed by the Bill. The present call for evidence raises technological and legal challenges that our membership explores in their research. As such, we believe that our contribution will add significant value to the scrutiny of the Draft Online Safety Bill. Summary (i) We agree that there is a need to address the regulation of online speech, and online content. We also accept, and are supportive of the need to enhance protection of vulnerable users online. (ii) That said, we have some serious concerns over the proposed Draft Online Safety Bill (OSB), both in terms of its substantive aim, but also it's likely practical implications. (iii) The policy intention is clear, but it is not similarly clear as to how it is intended that this legislation will operate in practice. (iv) The Draft OSB lacks clarity in relation to how it will operate in relation to some elements of free speech, especially in the areas of democratic and journalistic content. (v) It is our view that the Draft OSB is a work in progress at best, and poses significant risks to content, but also expression rights. We also retain concerns as to the choice of the regulatory body, and the likely enforceability requirements that will be needed. PLEASE CITE AS Kim Barker, Guido Noto La Diega, Ruth Flaherty, and Aysem Diker Vanberg, ‘Draft Online Safety Bill. Written evidence submitted by the British and Irish Law, Education and Technology Association (BILETA) (OSB0073)’ (UK Parliament, 28 September 2021

    The phase diagram of water from quantum simulations

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    The phase diagram of water has been calculated for the TIP4PQ/2005 model, an empirical rigid non-polarisable model. The path integral Monte Carlo technique was used, permitting the incorporation of nuclear quantum effects. The coexistence lines were traced out using the Gibbs-Duhem integration method, once having calculated the free energies of the liquid and solid phases in the quantum limit, which were obtained via thermodynamic integration from the classical value by scaling the mass of the water molecule. The resulting phase diagram is qualitatively correct, being displaced to lower temperatures by 15-20K. It is found that the influence of nuclear quantum effects are correlated to the tetrahedral order parameter.Comment: 10 pages, 6 figures, 1 tabl

    FCNC Processes from D-brane Instantons

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    Low string scale models might be tested at the LHC directly by their Regge resonances. For such models it is important to investigate the constraints of Standard Model precision measurements on the string scale. It is shown that highly suppressed FCNC processes like K0- bar K^0 oscillations or leptonic decays of the D0-meson provide non-negligible lower bounds on both the perturbatively and surprisingly also non-perturbatively induced string theory couplings. We present both the D-brane instanton formalism to compute such amplitudes and discuss various possible scenarios and their constraints on the string scale for (softly broken) supersymmetric intersecting D-brane models.Comment: 28 pages, 13 figures, reference added, 1 typo corrected, style file adde

    A microarray analysis of gene expression in the free-living stages of the parasitic nematode Strongyloides ratti

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    BACKGROUND: The nematode Strongyloides ratti has two adult phases in its lifecycle: one obligate, female and parasitic and one facultative, dioecious and free-living. The molecular control of the development of this free-living generation remains to be elucidated. RESULTS: We have constructed an S. ratti cDNA microarray and used it to interrogate changes in gene expression during the free-living phase of the S. ratti life-cycle. We have found very extensive differences in gene expression between first-stage larvae (L1) passed in faeces and infective L3s preparing to infect hosts. In L1 stages there was comparatively greater expression of genes involved in growth. We have also compared gene expression in L2 stages destined to develop directly into infective L3s with those destined to develop indirectly into free-living adults. This revealed relatively small differences in gene expression. We find little evidence for the conservation of transcription profiles between S. ratti and S. stercoralis or C. elegans. CONCLUSION: This is the first multi-gene study of gene expression in S. ratti. This has shown that robust data can be generated, with consistent measures of expression within computationally determined clusters and contigs. We find inconsistencies between EST representation data and microarray hybridization data in the identification of genes with stage-specific expression and highly expressed genes. Many of the genes whose expression is significantly different between L1 and iL3s stages are unknown beyond alignments to predicted genes. This highlights the forthcoming challenge in actually determining the role of these genes in the life of S. ratti

    The impact of sport participation on bone mass and geometry in adolescent males

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    Exercise is an effective approach for developing bone mass and adolescence is a key period to optimize bone health. However, sports specific training may have different effects on bone outcomes. This study examined the differences on bone outcomes between osteogenic (football) and non-osteogenic (swimming and cycling) sports and a control group in adolescent males. Methods: One hundred twenty one males (13.1±0.1 years) were measured: 41 swimmers, 37 footballers, 29 cyclists and 14 controls. Dual energy X-ray absorptiometry measured bone mineral density (BMD) and content (BMC) at lumbar spine, right and left hip and total body. Hip structural analysis evaluated bone geometry at the femoral neck. Quantitative ultrasound evaluated bone stiffness at both feet. Results: Footballers had significantly higher BMD at total body less head (7-9%), total hip (12-2%) and legs (7-11%) compared to all groups and significantly higher BMD at the femoral neck than controls (14%). Cyclists had higher BMD at the trochanter (10%) and BMC at the arms (10%) compared to controls. Geometrical analysis showed that footballers had significantly higher cross-sectional area (8-19%) compared to all groups, cross-sectional moment of inertia (17 %) compared to controls and section modulus compared to cyclists (11%) and controls (21%). Footballers had significantly higher bone stiffness compared to all groups (10-20%) at the dominant foot and (12-13%) at the nondominant foot compared to swimmers and controls. Conclusions: Adolescent male footballers exhibited higher bone density, geometry and stiffness compared to swimmers, cyclists and controls. Although swimmers and cyclists had higher bone outcomes compared to controls, these differences were not significant.The research leading to these results has received funding from the European Union Seventh Framework Programme ([FP7/2007-2013] under grant agreement n°. PCIG13-GA-2013-618496

    Mimivirus in Pneumonia Patients

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    Mimivirus, the largest virus known to date, is an amebal pathogen like Legionella spp. When mimivirus was used as an antigen in a migration inhibition factor assay, seroconversion was found in patients with both community- and hospital-acquired pneumonia. Mimivirus DNA was found in respiratory samples of patients with hospital-acquired pneumonia

    Thermoresponsive laterally-branched polythiophene phenylene derivative as water-soluble temperature sensor

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    Polymers with thermoresponsive properties have received a strong interest due to their potential applications. Here we report the synthesis and characterisation of a water soluble and thermoresponsive polythiophene derivative. Firstly, a polythiophene phenylene (PThP) functionalised with an initiator for atom transfer radical polymerization (ATRP) and azide groups on the side chains was synthesised. Secondly, ATRP was employed to graft poly(ethylene glycol) methacrylate (PEGMA) from the PThP to create a permanently water soluble conjugated polymer. Further functionalisation was then conducted through the `click' reaction with propargyl functionalised poly(2-n-propyl-2-oxazoline) to introduce thermoresponsivness. The polymer displayed lower critical solution temperature (LCST) behavior, as revealed by fluorescence and UV-Vis spectroscopy with potential use as soluble polymeric thermometer

    Interpretation and application of carbon isotope ratios in freshwater diatom silica

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    Carbon incorporated into diatom frustule walls is protected from degradation enabling analysis for carbon isotope composition (δ13Cdiatom). This presents potential for tracing carbon cycles via a single photosynthetic host with well-constrained ecophysiology. Improved understanding of environmental processes controlling carbon delivery and assimilation is essential to interpret changes in freshwater δ13Cdiatom. Here relationships between water chemistry and δ13Cdiatom from contemporary regional data sets are investigated. Modern diatom and water samples were collected from river catchments within England and lake sediments from across Europe. The data suggest dissolved, biogenically produced carbon supplied proportionately to catchment productivity was critical in the rivers and soft water lakes. However, dissolved carbon from calcareous geology overwhelmed the carbon signature in hard water catchments. Both results demonstrate carbon source characteristics were the most important control on δ13Cdiatom, with a greater impact than productivity. Application of these principles was made to a sediment record from Lake Tanganyika. δ13Cdiatom co-varied with δ13Cbulk through the last glacial and Holocene. This suggests carbon supply was again dominant and exceeded authigenic demand. This first systematic evaluation of contemporary δ13Cdiatom controls demonstrates that diatoms have the potential to supply a record of carbon cycling through lake catchments from sediment records over millennial timescales
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