245 research outputs found

    Bayesian modelling of the cool core galaxy group NGC 4325

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    We present an X-ray analysis of the radio-quiet cool-core galaxy group NGC 4325 (z=0.026) based on Chandra and ROSAT observations. The Chandra data were analysed using XSPEC deprojection, 2D spectral mapping and forward-fitting with parametric models. Additionally, a Markov chain Monte Carlo method was used to perform a joint Bayesian analysis of the Chandra and ROSAT data. The results of the various analysis methods are compared, particularly those obtained by forward-fitting and deprojection. The spectral mapping reveals the presence of cool gas displaced up to 10 kpc from the group centre. The Chandra X-ray surface brightness shows the group core to be highly disturbed, and indicates the presence of two small X-ray cavities within 15 kpc of the group core. The XSPEC deprojection analysis shows that the group has a particularly steep entropy profile, suggesting that an AGN outburst may be about to occur. With the evidence of prior AGN activity, but with no radio emission currently observed, we suggest that the group in in a pre-outburst state, with the cavities and displaced gas providing evidence of a previous, weak AGN outburst.Comment: 12 pages, 10 figures; accepted for publication in MNRA

    Interstratal dewatering origin for polygonal patterns of sand-filled cracks: a case study from late Proterozoic metasediments of Islay, Scotland

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    Sand-filled cracks from the Lower Fine-grained Quartzite of Dalradian (late Proterozoic) age on the Island of Islay, western Scotland, may be divided into two main types, both of which form orthogonal and non-orthogonal closed patterns on bedding surfaces. Type 1 cracks are short and lenticular in cross-section, contain sand which had been injected downwards, and are found on the bottoms of cross-laminated sandstone beds. Type 2 cracks cut several beds and preserve evidence of upward flow of water-saturated sand. Both types of crack developed through the interstratal intrusion of water-saturated sand into shrinkage cracks in mud or muddy sand, not, as previously thought, as a result of sub-aerial desiccation, or sub-aqueous cracking of the sediment surface (synaeresis). These cracks likely resulted from layer-parallel contraction caused by compaction of mudstone layers during burial. Seismic shock may have provided the trigger for the preferential development of polygonal crack patterns in these layers instead of the more usual small-scale dewatering structures. From a detailed comparison with published descriptions of filled cracks from a number of different geological environments, it is concluded that interstratal cracking is a mechanism which rivals sub-aerial desiccation in importance, and is more common in the geological record than is currently realized

    Historical light curve and search for previous outbursts of Nova KT Eridani (2009)

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    Context. Nova Eridani (2009) caught the eye of the nova community due to its fast decline from maximum, which was initially missed, and its subsequent development in the radio and X-ray wavelengths. This system also exhibits properties similar to those of the much smaller class of recurrent novae; themselves potential progenitors of Type Ia Supernovae. Aims. We aim to determine the nature and physical parameters of the KT Eri progenitor system. Methods. We searched the Harvard College Observatory archive plates for the progenitor of KT Eri to determine the nature of the system, particularly the evolutionary stage of the secondary.We used the data obtained to search for any periodic signal and the derived luminosity to estimate a recurrence timescale. Furthermore, by comparing the colours of the quiescent system on a colour-magnitude diagram we may infer the nature of the secondary star. Results. We identified the progenitor system of KT Eri and measured a quiescent magnitude of = 14.7 \pm 0.4. No previous outburst was found. However, we suggest that if the nova is recurrent it should be on a timescale of centuries. We find a periodicity at quiescence of 737 days which may arise from reflection effects and/or eclipses in the central binary. The periodicity and the quiescence magnitude of the system suggest that the secondary star is evolved and likely in, or ascending, the Red Giant Branch. A second period is evident at 376 days which has a sinusoidal like light curve. Furthermore, the outburst amplitude of ~ 9 magnitudes is inconsistent with those expected for fast classical novae (~ 17 magnitudes) which may lend further support for an evolved secondary. (Abridged)Comment: 6 pages, 5 figures, accepted for publication in A&

    Development of a core capability framework for qualified health professionals to optimise care for people with osteoarthritis: an OARSI initiative

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    Summary Objective Develop a generic trans-disciplinary, skills-based capability framework for health professionals providing care for people with OA. Design e-Delphi survey. An international inter-professional Delphi Panel (researchers; clinicians; consumer representatives) considered a draft framework (adapted from elsewhere) of 131 specific capabilities mapped to 14 broader capability areas across four domains (A: person-centred approaches; B: assessment, investigation and diagnosis; C: management, interventions and prevention; D: service and professional development). Over three rounds, the Panel rated their agreement (Likert or numerical rating scales) on whether each specific capability in Domains B and C was essential (core) for all health professionals when providing care for all people with OA. Those achieving consensus (=80% of Panel) rating of = seven out of ten (Round 3) were retained. Generic domains (A and D) were included in the final framework and amended based on Panel comments. Results 173 people from 31 countries, spanning 18 disciplines and including 26 consumer representatives, participated. The final framework comprised 70 specific capabilities across 13 broad areas i) communication; ii) person-centred care; iii) history-taking; iv) physical assessment; v) investigations and diagnosis; vi) interventions and care planning; vii) prevention and lifestyle interventions; viii) self-management and behaviour change; ix) rehabilitative interventions; x) pharmacotherapy; xi) surgical interventions; xii) referrals and collaborative working; and xiii) evidence-based practice and service development). Conclusion Experts agree that health professionals require an array of skills in person-centred approaches; assessment, investigation and diagnosis; management, interventions and prevention; and service and professional development to provide optimal care for people with OA

    Glaciolacustrine deposits formed in an ice-dammed tributary valley in the south-central Pyrenees: new evidence for late Pleistocene climate

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    Combined geomorphic features, stratigraphic characteristics and sedimentologic interpretation, coupled with optically stimulated luminescence (OSL) dates, of a glacio-fluvio-lacustrine sequence (Linás de Broto, northern Spain) provide new information to understand the palaeoenvironmental significance of dynamics of glacier systems in the south-central Pyrenees during the Last Glacial Cycle (≈130 ka to 14 ka). The Linás de Broto depositional system consisted of a proglacial lake fed primarily by meltwater streams emanating from the small Sorrosal glacier and dammed by a lateral moraine of the Ara trunk glacier. The resulting glacio-fluvio-lacustrine sequence, around 55 m thick, is divided into five lithological units consisting of braided fluvial (gravel deposits), lake margin (gravel and sand deltaic deposits) and distal lake (silt and clay laminites) facies associations. Evolution of the depositional environment reflects three phases of progradation of a high-energy braided fluvial system separated by two phases of rapid expansion of the lake. Fluvial progradation occurred during short periods of ice melting. Lake expansion concurred with ice-dam growth of the trunk glacier. The first lake expansion occurred over a time range between 55 ± 9 ka and 49 ± 11 ka, and is consistent with the age of the Viu lateral moraine (49 ± 8 ka), which marks the maximum areal extent of the Ara glacier during the Last Glacial Cycle. These dates confirm that the maximum areal extent of the glacier occurred during Marine Isotope Stages 4 and 3 in the south-central Pyrenees, thus before the Last Glacial Maximum. The evolution of the Linás de Broto depositional system during this maximum glacier extent was modulated by climate oscillations in the northern Iberian Peninsula, probably related to latitudinal shifts of the atmospheric circulation in the southern North-Atlantic Ocean, and variations in summer insolation intensity

    The Middle Pleistocene glacial evolution of northern East Anglia, UK: a dynamic tectonostratigraphic-parasequence approach

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    The Middle Pleistocene glacial history of northern East Anglia is a controversial topic with differing opinions surrounding chronology, provenance and the relative stratigraphic framework. Reconciling the stratigraphic framework of the region is an essential first step to developing onshore–offshore geological models and a robust event-driven chronological framework. Within this study a dynamic tectonostratigraphic–parasequence methodology is applied to deposits traditionally attributed to the Anglian Glaciation (Marine Isotope Stage 12). This approach offers an insight into ice-bed coupling during glaciation and how evolving boundary conditions influenced glacier dynamics. Six major tectonostratigraphic–parasequence assemblages (A1–A6) are recognized in northern East Anglia and correlate with successive advances into the region of North Sea or Pennine lobes of the British Ice Sheet. Individual tectonostratigraphic–parasequence assemblages are bound at their base by a sedimentary contact or, more commonly, a glacitectonic zone. The geometry and structural characteristics of these glacitectonic zones reflect temporal and spatial variations in ice-bed coupling (traction), a function of substrate rheology and, in turn, variations in lithology, porewater availability and thermo-mechanical properties. The role of permafrost may also be significant, promoting proglacial/ice-marginal thrust stacking in front of advancing ice and enhanced ice-bed decoupling during subsequent overriding and subglacial till accretio

    The Effects of Dietary Mobile Apps on Nutritional Outcomes in Adults with Chronic Diseases : A Systematic Review and Meta-Analysis

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    Abstract Background Dietary interventions are effective prevention and treatment strategies for chronic diseases; however, they require extensive commitment, time, and resources. Dietary mobile applications (apps) have gained popularity and are thus being incorporated into dietary management. Objective The aim of this review is to assess the effects of the use of dietary mobile apps on nutritional outcomes in adults with chronic diseases. Methods A systematic review was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using MEDLINE, PubMed, Embase, and CINAHL databases. The protocol was registered on PROSPERO. Intervention studies evaluating the nutritional outcomes of dietary apps, published in English between January 1, 2007 and November 15, 2017 were included. The methodological quality of included articles was assessed via the Academy of Nutrition and Dietetics\u27 Quality Criteria Checklist: Primary Research. Heterogeneity was confirmed using the I2 index and a random-effects meta-analysis was performed for randomized controlled trials. Estimates of the pooled mean difference were calculated for app usage compared to no app usage. Main outcomes measure Nutritional outcomes, categorized as food-/nutrition-related, anthropometric measurements, pertinent clinical/biochemical data, and nutrition-focused physical findings, were extracted from the included intervention studies. Results Upon completion of the searches, 18,649 articles were identified, and data were extracted from 22 articles. Pooled estimates showed a significantly greater decrease in weight ( “2.45 kg, 95% CI “3.33 to “1.58 kg; P Conclusions The findings of this systematic review and meta-analysis indicate that dietary mobile apps are effective self-monitoring tools, and that their use results in positive effects on measured nutritional outcomes in chronic diseases, especially weight loss

    Visualization of Murine Intranasal Dosing Efficiency Using Luminescent Francisella tularensis: Effect of Instillation Volume and Form of Anesthesia

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    Intranasal instillation is a widely used procedure for pneumonic delivery of drugs, vaccine candidates, or infectious agents into the respiratory tract of research mice. However, there is a paucity of published literature describing the efficiency of this delivery technique. In this report we have used the murine model of tularemia, with Francisella tularensis live vaccine strain (FTLVS) infection, to evaluate the efficiency of pneumonic delivery via intranasal dosing performed either with differing instillation volumes or different types of anesthesia. FTLVS was rendered luminescent via transformation with a reporter plasmid that constitutively expressed the Photorhabdus luminescens lux operon from a Francisella promoter. We then used an IVIS Spectrum whole animal imaging system to visualize FT dissemination at various time points following intranasal instillation. We found that instillation of FT in a dose volume of 10 µl routinely resulted in infection of the upper airways but failed to initiate infection of the pulmonary compartment. Efficient delivery of FT into the lungs via intranasal instillation required a dose volume of 50 µl or more. These studies also demonstrated that intranasal instillation was significantly more efficient for pneumonic delivery of FTLVS in mice that had been anesthetized with inhaled (isoflurane) vs. parenteral (ketamine/xylazine) anesthesia. The collective results underscore the need for researchers to consider both the dose volume and the anesthesia type when either performing pneumonic delivery via intranasal instillation, or when comparing studies that employed this technique
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