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ALMA reveals the coherence of the magnetic field geometry in OH 231.8+4.2
No full textIn a continuing effort to investigate the role of magnetic fields in evolved low and intermediate mass stars (principally regarding the shaping of their envelopes), we present new ALMA high resolution polarization data obtained for the nebula OH 231.8+4.2. We found that the polarized emission likely arises from aligned grains in the presence of magnetic fields rather than radiative alignment and self scattering. The ALMA data show well organized electricfield orientations in most of the nebula and the inferred magnetic field vectors (rotated by 90 degrees) trace an hourglass morphology centred on the central system of the nebula. One region in the southern part of OH 231.8+4.2 shows a less organized distribution probably due to the shocked environment. These findings, in conjunction with earlier investigations (maser studies and dust emission analysis at other scales and wavelengths) suggest an overallmagnetic hourglass located inside a toroidal field. We propose the idea that the magnetic field structure is closely related to the architecture of a magnetic tower and that the outflows were therefore magnetically launched. While the current dynamical effect of the fields might be weak in the equatorial plane principally due to the evolution of the envelope, it would still be affecting the outflows. In that regard, the measurement of the magnetic field at the stellar surface, which is still missing, combined with a full MHD treatment are required to betterunderstand and constrain the events occurring in OH 231.8+4.2
Very long baseline astrometry of PSR J1012+5307 and its implications on alternative theories of gravity
No full textPSR J1012+5307, a pulsar in orbit with a helium white dwarf (WD), has been timed with high precision for about 25 years. One of the main objectives of this long-term timing is to use the large asymmetry in gravitational binding energy between the neutron star and the WD to test gravitational theories. Such tests, however, will be eventually limited by the accuracy of the distance to the pulsar. Here, we present VLBI (very long baseline interferometry) astrometry results spanning approximately 2.5 years for PSR J1012+5307, obtained with the Very Long Baseline Array as part of the MSPSRπ project. These provide the first proper motion and absolute position for PSR J1012+5307 measured in a quasi-inertial reference frame. From the VLBI results, we measure a distance of 0.83+0.06 −0.02 kpc (all the estimates presented in the abstract are at 68% confidence) for PSR J1012+5307, which is the most precise obtained to date. Using the new distance, we improve the uncertainty of measurements of the unmodeled contributions to orbital period decay, which, combined with three other pulsars, places new constraints on the coupling constant for dipole gravitational radiation κD = (−1.7 ± 1.7) × 10−4 and the fractional time derivative of Newton’s gravitational constant G/G ˙ = −1.8 +5.6 −4.7 × 10−13 yr−1 in the local universe. As the uncertainties of the observed decays of orbital period for the four leading pulsarWD systems become negligible in ≈ 10 years, the uncertainties for G/G ˙ and κD will be improved to ≤ 1.5×10−13 yr−1 and ≤ 1.0×10−4, respectively, predominantly limited by the distance uncertainties
Synthesis of Candidate Advanced Technology Fuel: Uranium Diboride (UB2) via Carbo/Borothermic Reduction of UO2
No full textThe synthesis of uranium diboride (UB2) from uranium dioxide (UO2) has been carried out for the first time after a coordinated experimental and theoretical investigation. The reliable conversion of UO2 to UB2 is of importance when considering commercially relevant products (e.g. as an advanced technology fuel - ATF), avoiding the use of uranium metal as a reactant. UO2 was reduced and borated in-situ through careful combination with boron carbide (B4C) and graphite (carbo/borothermic reduction). The reaction is observed to only be favourable at low partial pressures of CO, here made possible through use of a vacuum furnace at temperatures up to 1800 ◦C. At higher partial pressures of CO, the product of the reaction is UB4. For phase pure UB2, excess B4C is required due to the formation of volatile boron oxides that are released from the reaction mixture as is observed when synthesising other borides through similar routes
Interviewer Effects in Biosocial Survey Measurements
No full textIncreasingly surveys are using interviewers to collect objective health measures, also known as biomeasures, to replace or supplement traditional self-reported health measures. However, the extent to which interviewers affect the (im)precision of biomeasurements is largely unknown. This paper investigates interviewer effects on several biomeasures collected in three waves of the National Social Life, Health, and Aging Project (NSHAP). Overall, we find low levels of interviewer effects, on average. This nevertheless hides important variation with touch sensory tests being especially problematic with 30% interviewer variation, and smell tests and timed balance/walk/chair stands having moderate interviewer variation of around 10%. Accounting for contextual variables that potentially interact with interviewer performance, including housing unit type and presence of a third person, failed to explain the interviewer variation. A discussion of these findings, their potential causes, and their implications for survey practice are provided in conclusion
Optimising the cut-off of the Bordier Aspergillus IgG ELISA for the diagnosis of chronic pulmonary aspergillosis
No full textAspergillus IgG detection is an essential tool in the diagnosis and treatment of chronic pulmonary aspergillosis (CPA), and is often positive in allergic bronchopulmonary aspergillosis and Aspergillus bronchitis. The Bordier ELISA had an 83.3% sensitivity (identical to ImmunoCap at a cut-off of 40mgA/L) and 97.3% specificity using a cut-off of 0.9 and a diagnostic accuracy of 90.9%
Introduction to Special Issue of Theology and Sexuality: Rethinking Relationships in Cyberspace
No full textInvestigating the perceived impact of psychosis on suicidal thoughts and behaviours
No full textThere is evidence showing a link between experiencing psychosis and suicidal thoughts and behaviours. However, individual accounts of the impact of psychosis on suicidal experiences have not been examined in detail. This study aimed to investigate the perceived impact of psychosis on suicidal thoughts and behaviours from the perspectives of individuals with these experiences. Semi-structured interviews with 20 people with non-affective psychosis and lifetime experiences of suicidal thoughts and/or behaviours were conducted. Data were analysed using inductive Thematic Analysis. Based on participants’ experiences of psychosis and suicidal thoughts and behaviours, three themes were identified, including 1. Psychosis experiences are immensely distressing, 2. Changes in behaviours and appraisals of self and 3. Suicidality as a means of escaping distress. A practical heuristic was proposed, describing a vicious cycle between psychological distress and changes in behaviours and self-appraisals, whereby suicidality was perceived as the only way to escape immense psychological pain. Hallucinations and delusions were central to the development of suicidal experiences. However, certain types of delusions, such as grandiose delusions, were sometimes found to reduce the intensity of suicidal experiences and associated psychological distress. It is necessary to examine the impact of psychosis on individuals, in order to assess the possibility of suicide-related experiences, as certain aspects of psychosis can have an amplifying effect, whereas others can have a weakening effect on those experiences. Minimising the immense psychological pain experienced by some people with psychosis and the inter-related suicidal thoughts and behaviours is of paramount importance for clinical practice
Cure monitoring and structural health monitoring of composites using microbraided distributed optical fibre
No full textIn this paper, cure monitoring of a composite laminate is conducted, followed by subsequent structural health monitoring (SHM). A distributed optical fibre (DOF) sensor was embedded between glass fibre fabric plies during manufacture; part of the DOF length was micro-braided using glass fibres, while the remaining length was left 'bare' (as-received condition). In situ and real-time strain measurement during the infusion and curing processes of the laminate was completed. Cure monitoring of composite materials using different fibre orientations, sensor locations, raw materials, and manufacturing methodshas been widely studied. However, no consensus was reached due to differences in raw materials, temperature profile, manufacturing method, fibre orientation, and sensor location. The manufactured composite plate was then subjected to repeated loading during a quasi-static four-point bending test,and the strain development along the length of the DOF was recorded. Comparable results were obtained from the micro-braided and bare sections of the DOF, showing the suitability of micro-braided optical fibres for real-time strain monitoring in composite structures. The micro-braiding DOFfacilitates handling for automated manufacturing methods and can be used to follow the full life cycle of a composite from fabrication till end-of-life
Loss of hepatocyte cell division leads to liver inflammation and fibrosis
No full textThe liver possesses a remarkable regenerative capacity based partly on the ability of hepatocytes to re-enter the cell cycle and divide to replace lost cells. This capability is substantially reduced upon chronic damage, but it is not clear if this is a cause or consequence of liver disease. Here, we investigate whether blocking hepatocyte division using two different mouse models affects physiology as well as clinical liver manifestations like fibrosis and inflammation. We find that in P14 Cdk1Liv-/- mice, where the division of hepatocytes is abolished, polyploidy, DNA damage, and increased p53 signaling are prevalent. Cdk1Liv-/- mice display classical markers of liver damage two weeks after birth, including elevated ALT, ALP, and bilirubin levels, despite the lack of exogenous liver injury. Inflammation was further studied using cytokine arrays, unveiling elevated levels of CCL2, TIMP1, CXCL10, and IL1-Rn in Cdk1Liv-/- liver, which resulted in increased numbers of monocytes. Ablation of CDK2-dependent DNAre-replication and polyploidy in Cdk1Liv-/- mice reversed most of these phenotypes. Overall, our data indicate that blocking hepatocyte division induces biological processes driving the onset of the disease phenotype. It suggests that the decrease in hepatocyte division observed in liver disease may not only be a consequence of fibrosis and inflammation, but also a pathological cue