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We extend the Annually Recalculated Virtual Annuity (ARVA) spending rule for retirement savings decumulation (Waring and Siegel (2015) Financial Analysts Journal, 71(1), 91–107) to include a cap and a floor on withdrawals. With a minimum withdrawal constraint, the ARVA strategy runs the risk of depleting the investment portfolio. We determine the dynamic asset allocation strategy which maximizes a weighted combination of expected total withdrawals (EW) and expected shortfall (ES), defined as the average of the worst 5% of the outcomes of real terminal wealth. We compare the performance of our dynamic strategy to simpler alternatives which maintain constant asset allocation weights over time accompanied by either our same modified ARVA spending rule or withdrawals that are constant over time in real terms. Tests are carried out using both a parametric model of historical asset returns as well as bootstrap resampling of historical data. Consistent with previous literature that has used different measures of reward and risk than EW and ES, we find that allowing some variability in withdrawals leads to large improvements in efficiency. However, unlike the prior literature, we also demonstrate that further significant enhancements are possible through incorporating a dynamic asset allocation strategy rather than simply keeping asset allocation weights constant throughout retirement.
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
We determine the optimal asset allocation to bonds and stocks using an annually recalculated virtual annuity (ARVA) spending rule for DC pension plan decumulation. Our objective function minimizes downside withdrawal variability for a given fixed value of total expected withdrawals. The optimal asset allocation is found using optimal stochastic control methods. We formulate the strategy as a solution to a Hamilton–Jacobi–Bellman (HJB) Partial Integro Differential Equation (PIDE). We impose realistic constraints on the controls (no-shorting, no-leverage, discrete rebalancing) and solve the HJB PIDEs numerically. Compared to a fixed-weight strategy which has the same expected total withdrawals, the optimal strategy has a much smaller average allocation to stocks and tends to de-risk rapidly over time. This conclusion holds in the case of a parametric model based on historical data and also in a bootstrapped market based on the historical data.
BACKGROUND: Metabolomics technology has the potential to revolutionize how we screen, diagnose, and treat cancer, as well as improve upon existing cancer molecular tests that may not sufficiently capture the complexity of most malignancies. In this study, we explore the clinical potential of metabolomics analysis in the diagnosis and risk-stratification of brain tumors. METHODS: To test the hypothesis that brain tumor type and survival could be predicted with metabolomics, we analyzed the pre-operative serum and urine samples of patients with glioblastoma (GBM), oligoastrocytoma (OA2), meningioma (M1) and compared them to healthy controls. (HC). Sera from immune-deficient NOD-SCID mice xenografted with human GBM brain tumor initiating cells were also studied. RESULTS: Metabolomics analysis of patient samples was able to accurately differentiate GBM, OA2, M1 and HC (p = 2.3 x 10-26). Subsequently, a prediction model developed and validated internally was able to diagnose GBM with a sensitivity of 86.7% and specificity of 93.8%, and distinguish whether a GBM patient possess O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation (p = 7.4 x 10-10). Within the MGMT methylated group, the model was able to predict longevity (p = 3.25 x 10-4). The model was also able to predict survival irrespective of MGMT methylation status (p = 2.9 x 10-6). CONCLUSIONS: In this study, we demonstrate that metabolomic analysis of patient biofluids can identify brain tumors, distinguish brain tumor subtypes, and independently predict MGMT status as well as longevity among GBM patients. Metabolomics analysis may facilitate non-invasive diagnosis of aggressive brain tumours.
People released from prison are at higher risk of mortality from potentially preventable causes than their peers in the general population. Because most studies of this phenomenon are reliant on registry data, there is little health and behavioural information available on those at risk, hampering the development of targeted, evidence-based preventive responses. Our aim was to identify modifiable risk and protective factors for external cause and cause-specific mortality after release from prison.
We undertook a nested case–control study using data from a larger retrospective cohort study of mortality after release from prison in Queensland, Australia between 1994 and 2007. Cases were 286 individuals who had died from external causes (drug overdose, suicide, transport accidents, or violence) matched with 286 controls on sex, Indigenous status, and release date. We extracted data from detention, case-management, and prison medical records.
Factors associated with increased risk of external cause mortality included use of heroin and other opioids in the community [odds ratio (OR) = 2.20, 95% CI 1.41–3.43, p < 0.001], a prescription for antidepressants during the current prison sentence (OR = 1.94, 95% CI 1.02–3.67, p = 0.042), a history of problematic alcohol use in the community (OR = 1.54, 95% CI 1.05–2.26, p = 0.028), and having ever served two or more custodial sentences (OR = 1.51, 95% CI 1.01–2.25, p = 0.045). Being married (OR = 0.45, 95% CI 0.29–0.70, p < 0.001) was protective. Fewer predictors were associated with cause-specific mortality.
We identified several behavioural, psychosocial, and clinical markers associated with mortality from preventable causes in people released from prison. Emerging evidence points to interventions that could be targeted at those at increased risk of external cause mortality. These include treatment and harm reduction programmes (for substance use), improving transitional support programmes and continuity of care (for mental health), diversion and drug reform (for repeat incarceration) and nurturing stable relationships during incarceration. The period of imprisonment and shortly after release provides a unique opportunity to improve the long-term health of ex-prisoners and overcome the disadvantage associated with imprisonment.
Does joining groups trigger a cascade of psychological processes that can result in a loss of individuality and lead to such outcomes as social loafing and poor decision-making? Rather than privileging the self comprising primarily individual qualities as the “true self,” a multilevel, multicomponent approach suggests that, in most cases, personal and collective identities are integrated and mutually sustaining.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
Bi-functional oxygen electrodes are an enabling component for rechargeable metal-air batteries and regenerative fuel cells, both of which are regarded as the next-generation energy devices with zero emission. Nonetheless, at the present, no single metal oxide component can catalyze both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with high performance which leads to large overpotential between ORR and OER. This work strives to address this limitation by studying the bi-functional electrocatalytic activity of the composite of a good ORR catalyst compound (e.g. palladium oxide, PdO) and a good OER catalyst compound (e.g. ruthenium oxide, RuO2) in alkaline solution (0.1M KOH) utilizing a thin-film rotating disk electrode technique. The studied compositions include PdO, RuO2, PdO/RuO2 (25wt.%/75wt.%), PdO/RuO2 (50wt.%/50wt.%) and PdO/RuO2 (75wt.%/25wt.%). The lowest overpotential (e.g. E (2 mA cm−2) - E (-2 mA cm−2)) of 0.82 V is obtained for PdO/RuO2 (25wt.%/75wt.%) (versus Ag|AgCl (3M NaCl) reference electrode).
There is increasing epidemiological evidence linking sub-optimal vitamin D status with overweight and obesity. Although increasing BMI and adiposity have also been negatively associated with the change in vitamin D status following supplementation, results have been equivocal. The aim of this randomised, placebo-controlled study was to investigate the associations between anthropometric measures of adiposity and the wintertime serum 25-hydroxycholecalciferol (25(OH)D) response to 15 μg cholecalciferol per d in healthy young and older Irish adults. A total of 110 young adults (20–40 years) and 102 older adults ( ≥ 64 years) completed the 22-week intervention with >85 % compliance. The change in 25(OH)D from baseline was calculated. Anthropometric measures of adiposity taken at baseline included height, weight and waist circumference (WC), along with skinfold thickness measurements to estimate fat mass (FM). FM was subsequently expressed as FM (kg), FM (%), FM index (FMI (FM kg/height m2)) and as a percentage ratio to fat-free mass (FFM). In older adults, vitamin D status was inversely associated with BMI (kg/m2), WC (cm), FM (kg and %), FMI (kg/m2) and FM:FFM (%) at baseline (r − 0·33, − 0·36, − 0·33, − 0·30, − 0·33 and − 0·27, respectively, all P values < 0·01). BMI in older adults was also negatively associated with the change in 25(OH)D following supplementation (β − 1·27, CI − 2·37, − 0·16, P = 0·026); however, no such associations were apparent in younger adults. Results suggest that adiposity may need to be taken into account when determining an adequate wintertime dietary vitamin D intake for healthy older adults residing at higher latitudes.
Influenza vaccines used in trials appeared to stimulate a small increase of saline-reactive anti-A1 antibodies in group O volunteers. There was no evidence that haemolysins were elicited by adjuvant vaccine. It is unlikely that influenza vaccines would cause ABO haemolytic disease in infants.
Trials of aqueous and oil adjuvant vaccines in young adult volunteers showed that severe local reactions were rare. However, the incidence of minor symptoms was too high for a vaccine which requires to be administered repeatedly. In contradistinction to some reports, systemic and allergic reactions did not constitute a problem.
In trials with polyvalent commercial influenza vaccines the antibody responses to oil-adjuvant vaccine persisted longer and were often higher. Antibody conversion was poor after all vaccines and delayed after adjuvant.
Six wheat/Agropyron intermedium addition lines are described on the basis of their phenotype and biochemical markers. An assessment of homoeology of each addition chromosome is made. Chromosome morphology, plant phenotype, isozyme and protein studies are compared with similar data for other wheat/alien addition lines and other members of the Triticeae. These comparisons give consistent results and it is concluded that addition lines L1, L2, L3, L4, L5 and L7 carry Agropyron chromosomes of homoeologous groups 7, 3, 1, 4, 5 and 6 respectively. This agrees with previously published work with one exception: the L5 chromosome belongs to homoeologous group 5 and not group 2 as proposed by Figueiras et al. (1986).