Gravitationally Lensed Gamma-Ray Bursts as Probes of Dark Compact Objects

If dark matter in the form of compact objects comprises a large fraction of the mass of the universe, then gravitational lensing effects on gamma-ray bursts are expected. We utilize BATSE and Ulysses data to search for lenses of different mass ranges, which cause lensing in the milli, pico, and femto regimes. Null results are used to set weak limits on the cosmological abundance of compact objects in mass ranges from 10$^{-16}$ to 10$^{-9}$ $M_{\odot}$. A stronger limit is found for a much discussed $\Omega = 0.15$ universe dominated by black holes of masses $\sim 10^{6.5} M_{\odot}$, which is ruled out at the $\sim$ 90% confidence level.Comment: 14 pages, 4 figures, fixed minor corrections. Accepted for publication in ApJ(L

Nature of fault planes in solid neutron star matter

The properties of tectonic earthquake sources are compared with those deduced here for fault planes in solid neutron-star matter. The conclusion that neutron-star matter cannot exhibit brittle fracture at any temperature or magnetic field is significant for current theories of pulsar glitches, and of the anomalous X-ray pulsars and soft-gamma repeaters.Comment: 5 AAS LaTeX pages 1 eps figur

Chandra astrometry sets a tight upper limit to the proper motion of SGR 1900+14

The soft gamma-ray repeater (SGR) SGR 1900+14 lies a few arcminutes outside the edge of the shell supernova remnant (SNR) G42.8+0.6. A physical association between the two systems has been proposed - for this and other SGR-SNR pairs - based on the expectation of high space velocities for SGRs in the framework of the magnetar model. The large angular separation between the SGR and the SNR center, coupled with the young age of the system, suggest a test of the association with a proper motion measurement. We used a set of three Chandra/ACIS observations of the field spanning 5 years to perform accurate relative astrometry in order to measure the possible angular displacement of the SGR as a function of time. Our investigation sets a 3-sigma upper limit of 70 mas/yr to the overall proper motion of the SGR. Such a value argues against an association of SGR 1900+14 with G42.8+0.6 and adds further support to the mounting evidence for an origin of the SGR within a nearby, compact cluster of massive stars.Comment: Accepted for publication in The Astrophysical Journal. 4 pages in emulate-apj styl

Calculation of the capacitance-voltage characteristic of GaAs, In0.53Ga0.47As, and InAs metal-oxide-semiconductor structures

The capacitance-voltage characteristic of GaAs, In0.53Ga0.47As, and InAs metal-oxide-semiconductor capacitors (MOSCAPs) is calculated in three cases. First, quantization is not considered, then quantization of the C-valley is included, and finally quantization of the Gamma-, X-, and L-valleys is included. The choice of valley energy-minima is shown to determine the onset of occupation of the satellite valleys and corresponding increase in total capacitance. An equivalent-oxide-thickness correction is defined and used as a figure-of-merit to compare III-V to Si MOSCAPs and as a metric for the density-of-states bottleneck. (C) 2011 American Institute of Physics. (doi:10.1063/1.3652699

The experiences and beliefs of people with severe haemophilia and healthcare professionals on pain management, and their views of using exercise as an aspect of intervention: a qualitative study

Purpose: To explore the experiences, views and beliefs of people with severe haemophilia and healthcare professionals (HCPs) on approaches for pain management, as well as their views on exercise being used as an aspect of management. Methods: Taking a qualitative inquiry approach using focus groups and semi-structured interviews, participants included people with severe haemophilia living with chronic pain and haemophilia HCPs. Data were analysed using reflexive thematic analysis. Results: Fourteen men with haemophilia with a median age of 47 (range 23–73) and six haemophilia HCPs agreed to participate. Of the people with haemophilia, 11 attended two focus groups and three were interviewed over telephone. Healthcare professionals were interviewed face-to-face. Two themes were conceptualised from the data: (i) haemophilia management and pain management is discordant (imbalance between good haemophilia care but poor pain management, historical medico-social influences on pain management, the need for trust); (ii) uncertain about exercise but clear on what matters (conflicting views on exercise, the need for proof of safety, personalised care). Conclusions: Options for effective pain management remain limited and what is used is heavily influenced by beliefs and experience. Exercise as a treatment option in pain management is conceptually acceptable for people with haemophilia. Effective pain management requires understanding of individual beliefs and fears, and a personalised approach supported by knowledgeable, trusted clinicians

Physiotherapy interventions for pain management in haemophilia: A systematic review

Purpose: Approximately 35%-50% of people with haemophilia (PWH) report living with chronic musculoskeletal pain. Although exercise based rehabilitation is effective for pain in other arthritises, there are no published guidelines for management of chronic pain in PWH. This review aims to evaluate and appraise the current evidence of effectiveness of physiotherapy interventions on (a) pain intensity, (b) quality of life (QoL) and (c) function in PWH. Methods: A systematic review of five databases AMED and CINAHL, EMBASE and MEDLINE and PEDro, as well as trial registries, grey literature and hand searching key journals was completed. Included studies were critically appraised and evaluated for risk of bias. The GRADE approach was used to rate the quality of the evidence. Results: Nine trials consisting of 235 participants met the inclusion criteria. All studies had an overall risk of bias with low methodological quality. Meta-analysis was not possible due to heterogeneity across trials. Studies comparing a range of physiotherapy interventions against no intervention showed no clear beneficial effect on pain intensity or QoL. Only one study, investigating hydrotherapy or land-based exercise against control, showed positive effect for pain intensity, but rated very low on GRADE assessment. Studies comparing one physiotherapy intervention against another showed no clear benefit on pain intensity, QoL or function. LASER with exercise and hydrotherapy were shown to have some positive effects on pain intensity, but no clear benefit on function. Conclusions: At present, there is limited evidence for the use of physiotherapy interventions in addressing the issue of pain in PWH. Better designed trials with higher quality and explicit methodology along with user involvement are needed to assess the efficacy of any proposed intervention

How does a lifetime of painful experiences influence sensations and beliefs about pain in adults with severe haemophilia? A qualitative study

Purpose: To explore the life experiences of pain in people with severe haemophilia and understand how such experiences influence beliefs and sensation of pain in adulthood. Methods: A qualitative inquiry approach using focus groups and semi-structured individual interviews was used. Participants included people with severe haemophilia living with chronic pain. Data were analysed using reflexive thematic analysis. Results: Fourteen men with a median age of 47 (range 23–73) agreed to take part. Eleven participated in two focus groups and three were interviewed over telephone. Two themes were conceptualised from the data: (i) haemophilia and pain – an evolving life biography (the personal narrative, historical, social, and medical context, continuous adaptation of activity choices, surveillance of pain and its meaning); (ii) “My normal isn’t normal” – identity and self-agency (pain as a feature of life and identify with severe haemophilia, loss of enjoyable activities balanced against staying active, barriers to participation). Conclusions: Pain is a constantly evolving, lifetime feature for many adults with haemophilia and it is viewed as part of their identity with their condition. Healthcare professionals working in haemophilia should try to better understand the influence of an individuals lived experience with their haemophilia on beliefs and behaviours of pai

Electrical characterization of the soft breakdown failure mode in MgO layers

The soft breakdown (SBD) failure mode in 20 nm thick MgO dielectric layers grown on Si substrates was investigated. We show that during a constant voltage stress, charge trapping and progressive breakdown coexist, and that the degradation dynamics is captured by a power-law time dependence. We also show that the SBD current-voltage (I-V) characteristics follow the power-law model I = aVb typical of this conduction mechanism but in a wider voltage window than the one reported in the past for SiO2. The relationship between the magnitude of the current and the normalized differential conductance was analyzed

Previously Claimed(/Unclaimed) X-ray Emission Lines in High Resolution Afterglow Spectra

We review the significance determination for emission lines in the Chandra HETGS spectrum for GRB020813, and we report on a search for additional lines in high resolution Chandra spectra. No previously unclaimed features are found. We also discuss the significance of lines sets reportedly discovered using XMM data for GRB011211 and GRB030227. We find that these features are likely of modest, though not negligible, significance.Comment: 4 pages, 1 figures, to appear in Santa Fe GRB Conference Proceedings, 200