The Optical Polarisation of the Vela Pulsar revisited

In this work we present a revised measurement of the phase-averaged optical polarisation of the Vela pulsar (PSR B0833-45), for which only one value has been published so far (Wagner & Seifert 2000). Our measurement has been obtained through an accurate reanalysis of archival polarisation observations obtained with the FORS instrument at the VLT. We have measured a phase-averaged linear polarisation degree P=9.4% +/- 4% and a position angle 146 +/- 11 deg, very close to the ones of the axis of symmetry of the X-ray arcs and jets detected by Chandra and of the pulsar proper motion.We have compared the measured phase-averaged optical polarisation with the expectations of different pulsars' magnetosphere models. We have found that all models consistently predict too large values of the phase-averaged linear polarization with respect to the observed one. This is probably a consequence of present models' limitations which neglect the contributions of various depolarisation effects. Interestingly, for the outer gap model we have found that, assuming synchrotron radiation for the optical emission, the observed polarisation position angle also implies an alignment between the pulsar rotational axis and the axis of symmetry of the X-ray arcs and jets.Comment: 8 pages, 4 figure

Thoracic Surgery and the Elderly; Is Lobectomy Safe in Octogenarians?

Purpose: Non-small cell lung cancer is the most common malignancy of the elderly, with 5-year survival estimates of 16.8%. The prognostic benefit of surgical resection for early lung cancer is irrefutable and maintained irrespective of age, even in patients over 75 years. Concerningly, despite the prognostic benefit of surgery there are deviations from standard treatment protocols with increasing age due to concerns of increased morbidity and mortality with surgery, without evidence to support this. Method: A state-wide retrospective registry study of Queensland's Cardiac Outcomes Registry's (QCOR) Thoracic Database examining the influence of age on the safety of Lung Resection (1 January 2016–20 April 2022). Results: This included 1,232 patients, mean age at surgery was 66 years (range 14–91 years), with 918 thoracotomies performed. Three deaths occurred within 30-days (0.24%). Octogenarians (n=60) had lower rates of smoking (26% vs 6%), respiratory, cardiovascular, and cerebrovascular disease suggesting this subset of patients is carefully selected. Octogenarian status was not associated with an increased all-cause morbidity (p=0.09) or 30-day mortality (p=0.06). Further to this it was not associated with re-operation (4.4% vs 8.3%, p=0.1), increased postoperative stay (6.66 vs 6.65 days, p=0.99) or myocardial infarction. An independent predictor of morbidity was male sex (OR 1.58, CI 1.2–2.1 p=0.001). Conclusion: Age ≥80 years did not increase surgical morbidity or mortality in the appropriately selected patient and should not be a barrier to referral for consideration of surgical resection

The influence of the COVID-19 pandemic on lung cancer surgery in Queensland

Background: The coronavirus disease-19 (COVID-19) pandemic poses unprecedented challenges to global healthcare. The contemporary influence of COVID-19 on the delivery of lung cancer surgery has not been examined in Queensland. Methods: We performed a retrospective registry analysis of the Queensland Cardiac Outcomes Registry (QCOR), thoracic database examining all adult lung cancer resections across Queensland from 1/1/2016 to 30/4/2022. We compared the data prior to, and after, the introduction of COVID-restrictions. Results: There were 1207 patients. Mean age at surgery was 66 years and 1115 (92%) lobectomies were performed. We demonstrated a significant delay from time of diagnosis to surgery from 80 to 96 days (P < 0.0005), after introducing COVID-restrictions. The number of surgeries performed per month decreased after the pandemic and has not recovered (P = 0.012). 2022 saw a sharp reduction in cases with 49 surgeries, compared to 71 in 2019 for the same period. Conclusion: Restrictions were associated with a significant increase in pathological upstaging, greatest immediately after the introduction of COVID-restrictions (IRR 1.71, CI 0.93–2.94, P = 0.05). COVID-19 delayed the access to surgery, reduced surgical capacity and consequently resulted in pathological upstaging throughout Queensland

Finite Element Simulation of Dense Wire Packings

A finite element program is presented to simulate the process of packing and coiling elastic wires in two- and three-dimensional confining cavities. The wire is represented by third order beam elements and embedded into a corotational formulation to capture the geometric nonlinearity resulting from large rotations and deformations. The hyperbolic equations of motion are integrated in time using two different integration methods from the Newmark family: an implicit iterative Newton-Raphson line search solver, and an explicit predictor-corrector scheme, both with adaptive time stepping. These two approaches reveal fundamentally different suitability for the problem of strongly self-interacting bodies found in densely packed cavities. Generalizing the spherical confinement symmetry investigated in recent studies, the packing of a wire in hard ellipsoidal cavities is simulated in the frictionless elastic limit. Evidence is given that packings in oblate spheroids and scalene ellipsoids are energetically preferred to spheres.Comment: 17 pages, 7 figures, 1 tabl

Dual tasking impairments are associated with striatal pathology in Huntington’s disease

Background: Recent findings suggest that individuals with Huntington’s disease (HD) have an impaired capacity to execute cognitive and motor tasks simultaneously, or dual task, which gradually worsens as the disease advances. The onset and neuropathological changes mediating impairments in dual tasking in individuals with HD are unclear. The reliability of dual tasking assessments for individuals with HD is also unclear. Objectives: To evaluate differences in dual tasking performance between individuals with HD (presymptomatic and prodromal) and matched controls, to investigate associations between striatal volume and dual tasking performance, and to determine the reliability of dual tasking assessments. Methods: Twenty individuals with HD (10 presymptomatic and 10 prodromal) and 20 healthy controls were recruited for the study. Individuals undertook four single and dual task assessments, comprising motor (postural stability or force steadiness) and cognitive (simple or complex mental arithmetic) components, with single and dual tasks performed three times each. Participants also undertook a magnetic resonance imaging assessment. Results: Compared to healthy controls, individuals with presymptomatic and prodromal HD displayed significant deficits in dual tasking, particularly cognitive task performance when concurrently undertaking motor tasks (P \u3c 0.05). The observed deficits in dual tasking were associated with reduced volume in caudate and putamen structures (P \u3c 0.05),however, not with clinical measures of disease burden. An analysis of the reliability of dual tasking assessments revealed moderate to high test–retest reliability [ICC: 0.61-0.99] for individuals with presymptomatic and prodromal HD and healthy controls. Conclusions: Individuals with presymptomatic and prodromal HD have significant deficits in dual tasking that are associated with striatal degeneration. Findings also indicate that dual tasking assessments are reliable in individuals presymptomatic and prodromal HD and healthy controls

Ascorbic acid is associated with favourable hormonal profiles among infertile males

IntroductionInfertility affects about 16% of North American couples, with the male factor contributing to ∼30% of cases. Reproductive hormones play an integral role in regulating the reproductive system and consequently, fertility. Oxidative stress reduces testosterone synthesis, and reduction in oxidative stress can improve hormone profiles. Ascorbic acid is a potent antioxidant that accounts for up to 65% of seminal antioxidant activity; however, its effects on reproductive hormones in humans are unknown.MethodsThe objective was to determine the association between serum ascorbic acid concentrations and male reproductive hormones. We conducted a cross-sectional study involving infertile males (n = 302) recruited from Mount Sinai Hospital, Toronto. Serum was analyzed for ascorbic acid, luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone (TT), prolactin and estradiol. Statistical analyses included Spearman's rank correlations, linear regressions, logistic regressions, simple slope and Johnson-Neyman procedures.ResultsAfter adjusting for covariates, ascorbic acid was inversely associated with LH (P = 0.01). Ascorbic acid was positively associated with TT only among males over the age of 41.6 years (P = 0.01).DiscussionOur findings show that ascorbic acid is associated with higher testosterone levels and improved androgenic status in infertile males, and some of the effects appear to be age dependent

Community Genetics screening in a pandemic: solutions for pre-test education, informed consent, and specimen collection

A Community Genetics carrier screening program for the Jewish community has operated on-site in high schools in Sydney (Australia) for 25 years. During 2020, in response to the COVID-19 pandemic, government-mandated social-distancing, ‘lock-down’ public health orders, and laboratory supply-chain shortages prevented the usual operation and delivery of the annual testing program. We describe development of three responses to overcome these challenges: (1) pivoting to online education sufficient to ensure informed consent for both genetic and genomic testing; (2) development of contactless telehealth with remote training and supervision for collecting genetic samples using buccal swabs; and (3) a novel patient and specimen identification ‘GeneTrustee’ protocol enabling fully identified clinical-grade specimens to be collected and DNA extracted by a research laboratory while maintaining full participant confidentiality and privacy. These telehealth strategies for education, consent, specimen collection and sample processing enabled uninterrupted delivery and operation of complex genetic testing and screening programs even amid pandemic restrictions. These tools remain available for future operation and can be adapted to other programs

A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities