Is the PAMELA Positron Excess Winos?

Recently the PAMELA satellite-based experiment reported an excess of galactic positrons that could be a signal of annihilating dark matter. The PAMELA data may admit an interpretation as a signal from a wino-like LSP of mass about 200 GeV, normalized to the local relic density, and annihilating mainly into W-bosons. This possibility requires the current conventional estimate for the energy loss rate of positrons be too large by roughly a factor of five. Data from anti-protons and gamma rays also provide tension with this interpretation, but there are significant astrophysical uncertainties associated with their propagation. It is not unreasonable to take this well-motivated candidate seriously, at present, in part because it can be tested in several ways soon. The forthcoming PAMELA data on higher energy positrons and the FGST (formerly GLAST) data, should provide important clues as to whether this scenario is correct. If correct, the wino interpretation implies a cosmological history in which the dark matter does not originate in thermal equilibrium.Comment: 7 pages, 4 figue

Optimisation of wind turbine inspection intervals.

The choice of correct inspection intervals poses a serious challenge to industries that utilise physical assets. Too short an interval increases operational cost and waste production time while too long an interval increases the likelihood of unexpected asset failures. Failure Modes and Effect Criticality Analysis (FMECA) is a technique that permits qualitative evaluation of assets' functions to predict critical failure modes and the resultant consequences to determine appropriate maintenance tasks for the assets. The Delay-Time Maintenance Model (DTMM) is a quantitative maintenance optimisation technique that examines equipment failure patterns by taking into account failure consequences, inspection time and cost in order to determine optimum inspection interval. In this paper, a hybrid of FMECA and DTMM is used to assess the failure characteristics of a selected subsystems of a chosen wind turbine. Optimal inspection intervals for critical subsystems of the wind turbine are determined to minimise its total life-cycle cost

Brainstem metastases treated with Gamma Knife stereotactic radiosurgery: the Indiana University Health experience

Brainstem metastases offer a unique challenge in cancer treatment, yet stereotactic radiosurgery (SRS) has proven to be an effective modality in treating these tumors. This report discusses the clinical outcomes of patients with brainstem metastases treated at Indiana University with Gamma Knife (GK) radiosurgery from 2008 to 2016. 19 brainstem metastases from 14 patients who had follow-up brain imaging were identified. Median tumor volume was 0.04 cc (range: 0.01-2.0 cc). Median prescribed dose was 17.5 Gy to the 50% isodose line (range: 14-22 Gy). Median survival after GK SRS treatment to brainstem lesion was 17.2 months (range: 2.8-45.6 months). The experience at Indiana University confirms the safety and efficacy of range of GK SRS prescription doses (14-22 Gy) to brainstem metastases

Survival and complications of stereotactic radiosurgery

Background: Utilization of stereotactic radiosurgery (SRS) for treatment of high-grade gliomas (HGGs) has been slowly increasing with variable reported success rates. Objective: Systematic review of the available data to evaluate the efficacy of SRS as a treatment for HGG with regards to median overall survival (OS) and progression-free survival (PFS), in addition to ascertaining the rate of radiation necrosis and other SRS-related major neurological complications. Methods: Literature searches were performed for publications from 1992 to 2016. The pooled estimates of median PFS and median OS were calculated as a weighted estimate of population medians. Meta-analyses of published rates of radiation necrosis and other major neurological complications were also performed. Results: Twenty-nine studies reported the use of SRS for recurrent HGG, and 16 studies reported the use of SRS for newly diagnosed HGG. For recurrent HGG, the pooled estimates of median PFS and median OS were 5.42 months (3–16 months) and 20.19 months (9–65 months), respectively; the pooled radiation necrosis rate was 5.9% (0–44%); and the pooled estimates of major neurological complications rate was 3.3% (0–23%). For newly diagnosed HGG, the pooled estimates of median PFS and median OS were 7.89 months (5.5–11 months) and 16.87 months (9.5–33 months) respectively; the pooled radiation necrosis rate was 6.5% (0–33%); and the pooled estimates of other major neurological complications rate was 1.5% (0–25%). Conclusion: Our results suggest that SRS holds promise as a relatively safe treatment option for HGG. In terms of efficacy at this time, there are inadequate data to support routine utilization of SRS as the standard of care for newly diagnosed or recurrent HGG. Further studies should be pursued to define more clearly the therapeutic role of SRS

Efficacy of pimobendan in the prevention of congestive heart failure or sudden death in doberman pinschers with preclinical dilated cardiomyopathy (the PROTECT study)

<p>Background: The benefit of pimobendan in delaying the progression of preclinical dilated cardiomyopathy (DCM) in Dobermans is not reported.</p> <p>Hypothesis: That chronic oral administration of pimobendan to Dobermans with preclinical DCM will delay the onset of CHF or sudden death and improve survival.</p> <p>Animals: Seventy-six client-owned Dobermans recruited at 10 centers in the UK and North America.</p> <p>Methods: The trial was a randomized, blinded, placebo-controlled, parallel group multicenter study. Dogs were allocated in a 1:1 ratio to receive pimobendan (Vetmedin capsules) or visually identical placebo.</p> <p>The composite primary endpoint was prospectively defined as either onset of CHF or sudden death. Time to death from all causes was a secondary endpoint.</p> <p>Results: The proportion of dogs reaching the primary endpoint was not significantly different between groups (P = .1). The median time to the primary endpoint (onset of CHF or sudden death) was significantly longer in the pimobendan (718 days, IQR 441–1152 days) versus the placebo group (441 days, IQR 151–641 days) (log-rank P = 0.0088). The median survival time was significantly longer in the pimobendan (623 days, IQR 491–1531 days) versus the placebo group (466 days, IQR 236–710 days) (log-rank P = .034).</p> <p>Conclusion and Clinical Importance: The administration of pimobendan to Dobermans with preclinical DCM prolongs the time to the onset of clinical signs and extends survival. Treatment of dogs in the preclinical phase of this common cardiovascular disorder with pimobendan can lead to improved outcome.</p&gt

Radiation-Induced Large Vessel Cerebral Vasculopathy in Pediatric Patients with Brain Tumors Treated with Proton Radiotherapy

Purpose The purpose of this research is to evaluate the incidence, time to development, imaging patterns, risk factors, and clinical significance of large vessel cerebral vasculopathy in pediatric patients with brain tumors treated with proton radiotherapy. Materials and Methods A retrospective study was performed on 75 consecutive pediatric patients with primary brain tumors treated with proton radiotherapy. Radiation-induced large vessel cerebral vasculopathy (RLVCV) was defined as intracranial large vessel arterial stenosis or occlusion confirmed on MRA, CTA, and/or catheter angiography within an anatomic region with previous exposure to proton beam therapy and not present prior to radiotherapy. Clinical records were used to determine the incidence, timing, radiation dose to the large vessels, and clinical significance associated with the development of large vessel vasculopathy in these patients. Results RLVCV was present in 5/75 (6.7%) of patients and included tumor pathologies of craniopharyngioma (2), ATRT (1), medulloblastoma (1), and anaplastic astrocytoma (1). Median time from completion of radiotherapy to development was 1.5 years (mean 3.0 years; range 1.0-7.5 years). Neither mean age at time of radiotherapy (5.1 years) nor mean radiotherapy dose to the large vessels (54.5 Gy) were statistically significant risk factors. Four of the five patients with RLVCV presented with acute stroke, and demonstrated MRI evidence of acute infarcts in the expected vascular distributions. Angiography studies demonstrated collateral vessel formation in only two of the patients with RLVCV. No patients demonstrated acute hemorrhage or aneurysm. Two patients were treated with pial synangiomatosis surgery. Conclusion RLVCV can occur in pediatric patients with brain tumors treated with proton radiotherapy. Further studies are necessary to determine potential risk factors for large vessel vasculopathy with proton radiotherapy in comparison with conventional photon radiotherapy

Multiple cosmic sources for meteorite macromolecules?

The major organic component in carbonaceous meteorites is an organic macromolecular material. The Murchison macromolecular material comprises aromatic units connected by aliphatic and heteroatom-containing linkages or occluded within the wider structure. The macromolecular material source environment remains elusive. Traditionally, attempts to determine source have strived to identify a single environment. Here we apply a highly efficient hydrogenolysis method to liberate units from the macromolecular material and use mass spectrometric techniques to determine their chemical structures and individual stable carbon isotope ratios. We confirm that the macromolecular material comprises a labile fraction with small aromatic units enriched in 13C and a refractory fraction made up of large aromatic units depleted in 13C. Our findings suggest that the macromolecular material may be derived from at least two separate environments. Compound specific carbon isotope trends for aromatic compounds with carbon number may reflect mixing of the two sources. The story of the quantitatively dominant macromolecular material in meteorites appears to be made up of more than one chapter