Utilisation of intensive foraging zones by female Australian fur seals.

Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch

Non-fatal self-harm in Scottish military veterans: a retrospective cohort study of 57,000 veterans and 173,000 matched non-veterans

Purpose: Although suicide risk in veterans has been widely studied, there is little information on the risk of non-fatal self-harm in this population. We used data from the Scottish Veterans Health Study to conduct an epidemiological analysis of self-harm in veterans, in comparison with people who have never served. Methods: We conducted a retrospective, 30-year cohort study of 56,205 veterans born 1945–1985, and 172,741 people with no record of military service, and used Cox proportional hazard models to examine the association between veteran status and cumulative risk of non-fatal self-harm, overall and stratified by birth cohort, sex and length of service. We also examined mental and physical comorbidities, and association of suicide with prior self-harm. Results: There were 1620 (2.90%) first episodes of self-harm in veterans, compared with 4212 (2.45%) in non-veterans. The difference was statistically significant overall (unadjusted HR 1.27, 95% CI 1.21–1.35, p < 0.001). The risk was highest in the oldest veterans, and in the early service leavers who failed to complete initial training (unadjusted HR 1.69, 95% CI 1.50–1.91, p < 0.001). The risk reduced with longer service and in the intermediate birth cohorts but has increased again in the youngest cohort. Conclusions: The highest risk of non-fatal self-harm was in veterans with the shortest service, especially those who did not complete training or minimum engagement, and in the oldest birth cohorts, whilst those who had served the longest were at reduced risk. The risk has increased again in the youngest veterans, and further study of this subgroup is indicated

Private Governance Responses to Climate Change: The Case of Global Civil Aviation

This Article explores how private governance can reduce the climate effects of global civil aviation. The civil aviation sector is a major contributor to climate change, accounting for emissions comparable to a top ten emitting country. National and international governmental bodies have taken important steps to address civil aviation, but the measures adopted to date are widely acknowledged to be inadequate. Civil aviation poses particularly difficult challenges for government climate mitigation efforts. Many civil aviation firms operate globally, emissions often occur outside of national boundaries, nations differ on their respective responsibilities, and demand is growing rapidly. Although promising new technologies are emerging, they will take time to develop and adopt. This Article argues that private initiatives can overcome many of these barriers. Private initiatives can motivate civil aviation firms to act absent government pressure at the national level and can create pressure for mitigation that transcends national boundaries. The Article argues that it is time to develop a private climate governance agenda for civil aviation and identifies examples of the types of existing and new initiatives that could be included in the effort. If public and private policymakers can overcome the tendency to focus almost exclusively on public governance, private initiatives can yield large and prompt emissions reductions from global civil aviation, buy time for more comprehensive government measures, and complement the government measures when they occur

Persistent Evidence of a Jovian Mass Solar Companion in the Oort Cloud

We present an updated dynamical and statistical analysis of outer Oort cloud cometary evidence suggesting the sun has a wide-binary Jovian mass companion. The results support a conjecture that there exists a companion of mass ~ 1-4 M_Jup orbiting in the innermost region of the outer Oort cloud. Our most restrictive prediction is that the orientation angles of the orbit normal in galactic coordinates are centered on the galactic longitude of the ascending node Omega = 319 degree and the galactic inclination i = 103 degree (or the opposite direction) with an uncertainty in the normal direction subtending ~ 2% of the sky. A Bayesian statistical analysis suggests that the probability of the companion hypothesis is comparable to or greater than the probability of the null hypothesis of a statistical fluke. Such a companion could also have produced the detached Kuiper Belt object Sedna. The putative companion could be easily detected by the recently launched Wide-field Infrared Survey Explorer (WISE).Comment: 41 pages, 9 figures, submitted to ICARU

Bayesian Analysis of Hot Jupiter Radius Anomalies: Evidence for Ohmic Dissipation?

The cause of hot Jupiter radius inflation, where giant planets with $T_{\rm eq}$ $>1000$ K are significantly larger than expected, is an open question and the subject of many proposed explanations. Rather than examine these models individually, this work seeks to characterize the anomalous heating as a function of incident flux, $\epsilon(F)$, needed to inflate the population of planets to their observed sizes. We then compare that result to theoretical predictions for various models. We examine the population of about 300 giant planets with well-determined masses and radii and apply thermal evolution and Bayesian statistical models to infer the anomalous power as a function of incident flux that best reproduces the observed radii. First, we observe that the inflation of planets below about M=0.5 \;\rm{M}_\rm{J} appears very different than their higher mass counterparts, perhaps as the result of mass loss or an inefficient heating mechanism. As such, we exclude planets below this threshold. Next, we show with strong significance that $\epsilon(F)$ increases with $T_{\rm{eq}}$ towards a maximum of $\sim 2.5\%$ at $T_{\rm{eq}} \approx 1500$ K, and then decreases as temperatures increase further, falling to $\sim0.2\%$ at T_\rm{eff}= 2500 K. This high-flux decrease in inflation efficiency was predicted by the Ohmic dissipation model of giant planet inflation but not other models. We also explicitly check the thermal tides model and find that it predicts far more variance in radii than is observed. Thus, our results provide evidence for the Ohmic dissipation model and a functional form for $\epsilon(F)$ that any future theories of hot Jupiter radii can be tested against.Comment: 14 pages, 14 figures, accepted to The Astronomical Journal. This revision revises the description of statistical methods for clarity, but the conclusions remain the sam

Synchronization of Coupled Boolean Phase Oscillators

We design, characterize, and couple Boolean phase oscillators that include state-dependent feedback delay. The state-dependent delay allows us to realize an adjustable coupling strength, even though only Boolean signals are exchanged. Specifically, increasing the coupling strength via the range of state-dependent delay leads to larger locking ranges in uni- and bi-directional coupling of oscillators in both experiment and numerical simulation with a piecewise switching model. In the unidirectional coupling scheme, we unveil asymmetric triangular-shaped locking regions (Arnold tongues) that appear at multiples of the natural frequency of the oscillators. This extends observations of a single locking region reported in previous studies. In the bidirectional coupling scheme, we map out a symmetric locking region in the parameter space of frequency detuning and coupling strength. Because of large scalability of our setup, our observations constitute a first step towards realizing large-scale networks of coupled oscillators to address fundamental questions on the dynamical properties of networks in a new experimental setting.Comment: 8 pages, 8 figure