Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations?

Killer whales (Orcinus orca) are important predators in high latitudes, where their ecological impact is mediated through their movements. We used satellite telemetry to provide the first evidence of migration for killer whales, characterized by fast (more than 12 km h−1, 6.5 knots) and direct movements away from Antarctic waters by six of 12 type B killer whales tagged when foraging near the Antarctic Peninsula, including all tags transmitting for more than three weeks. Tags on five of these whales revealed consistent movements to subtropical waters (30–37° S) off Uruguay and Brazil, in surface water temperatures ranging from −1.9°C to 24.2°C; one 109 day track documented a non-stop round trip of almost 9400 km (5075 nmi) in just 42 days. Although whales travelled slower in the warmest waters, there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding. Furthermore, these movements were aseasonal, initiating over 80 days between February and April; one whale returned to within 40 km of the tagging site at the onset of the austral winter in June. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a physiological constraint that may also affect other whales

Transport composite fuselage technology: Impact dynamics and acoustic transmission

A program was performed to develop and demonstrate the impact dynamics and acoustic transmission technology for a composite fuselage which meets the design requirements of a 1990 large transport aircraft without substantial weight and cost penalties. The program developed the analytical methodology for the prediction of acoustic transmission behavior of advanced composite stiffened shell structures. The methodology predicted that the interior noise level in a composite fuselage due to turbulent boundary layer will be less than in a comparable aluminum fuselage. The verification of these analyses will be performed by NASA Langley Research Center using a composite fuselage shell fabricated by filament winding. The program also developed analytical methodology for the prediction of the impact dynamics behavior of lower fuselage structure constructed with composite materials. Development tests were performed to demonstrate that the composite structure designed to the same operating load requirement can have at least the same energy absorption capability as aluminum structure

Solution of the Fokker-Planck equation with a logarithmic potential and mixed eigenvalue spectrum

Motivated by a problem in climate dynamics, we investigate the solution of a Bessel-like process with negative constant drift, described by a Fokker-Planck equation with a potential V(x) = - [b \ln(x) + a\, x], for b>0 and a<0. The problem belongs to a family of Fokker-Planck equations with logarithmic potentials closely related to the Bessel process, that has been extensively studied for its applications in physics, biology and finance. The Bessel-like process we consider can be solved by seeking solutions through an expansion into a complete set of eigenfunctions. The associated imaginary-time Schroedinger equation exhibits a mix of discrete and continuous eigenvalue spectra, corresponding to the quantum Coulomb potential describing the bound states of the hydrogen atom. We present a technique to evaluate the normalization factor of the continuous spectrum of eigenfunctions that relies solely upon their asymptotic behavior. We demonstrate the technique by solving the Brownian motion problem and the Bessel process both with a negative constant drift. We conclude with a comparison with other analytical methods and with numerical solutions.Comment: 21 pages, 8 figure

Perceptions of the Use of Alcohol and Drugs after Sudden Bereavement by Unnatural Causes: Analysis of Online Qualitative Data

Bereavement is associated with an increased risk of psychiatric morbidity and all-cause mortality, particularly in younger people and after unnatural deaths. Substance misuse is implicated but little research has investigated patterns of drug or alcohol use after bereavement. We used a national online survey to collect qualitative data describing whether and how substance use changes after sudden bereavement. We conducted thematic analysis of free-text responses to a question probing use of alcohol and drugs after the sudden unnatural (non-suicide) death of a family member or a close friend. We analysed data from 243 adults in British Higher Education Institutions aged 18-40, identifying two main themes describing post-bereavement alcohol or drug use: (1) sense of control over use of drugs or alcohol (loss of control versus self-discipline), (2) harnessing the specific effects of drugs or alcohol. Across themes we identified age patterning in relation to substance misuse as a form of rebellion among those bereaved in childhood, and gender patterning in relation to men using alcohol to help express their emotions. The limitations of our sampling mean that these findings may not be generalizable from highly-educated settings to young people in the general population. Our findings describe how some young bereaved adults use drugs and alcohol to help them cope with traumatic loss, and suggest how clinicians might respond to any difficulties controlling substance use

Use of Alcohol and Unprescribed Drugs after Suicide Bereavement: Qualitative Study

Studies describing the impact of suicide bereavement report an excess risk of suicide, suicide attempt, psychiatric illness, and drug and alcohol use disorders compared with the general population. However, the nature of patterns of drug and alcohol use after suicide bereavement is unclear. We used an online survey to collect qualitative data to understand whether and how drug and alcohol use changes after suicide bereavement. We conducted thematic analysis of free-text responses to a question capturing their use of alcohol and drugs after the suicide of a family member or a close friend. Analysing data from 346 adults in Britain aged 18–40, we identified three main themes describing the relationship of suicide bereavement to alcohol or drug use: (1) control over drug or alcohol use, (2) the perceived purpose of using drugs or alcohol, and (3) the attribution of drug or alcohol misuse to external factors. Overlying these themes were dimensions of control and of awareness of potential harms. This study highlights that increased use of drugs and alcohol after suicide bereavement may form part of a bereaved person’s coping strategies, and that sensitive approaches are needed when judging whether and when to intervene

The mental health of lesbian, gay, and bisexual adults compared with heterosexual adults: results of two nationally representative English household probability samples

BACKGROUND: Evidence on inequalities in mental health in lesbian, gay, and bisexual people arises primarily from non-random samples. AIMS: To use a probability sample to study change in mental health inequalities between two survey points, 7 years apart; the contribution of minority stress; and whether associations vary by age, gender, childhood sexual abuse, and religious identification. METHODS: We analysed data from 10 443 people, in two English population-based surveys (2007 and 2014), on common mental disorder (CMD), hazardous alcohol use, and illicit drug use. Multivariable models were adjusted for age, gender, and economic factors, adding interaction terms for survey year, age, gender, childhood sexual abuse, and religious identification. We explored bullying and discrimination as mediators. RESULTS: Inequalities in risks of CMD or substance misuse were unchanged between 2007 and 2014. Compared to heterosexuals, bisexual, and lesbian/gay people were more likely to have CMD, particularly bisexual people [adjusted odds ratio (AOR) = 2.86; 95% CI 1.83-4.46], and to report alcohol misuse and illicit drug use. When adjusted for bullying, odds of CMD remained elevated only for bisexual people (AOR = 3.21; 95% CI 1.64-6.30), whilst odds of alcohol and drug misuse were unchanged. When adjusted for discrimination, odds of CMD and alcohol misuse remained elevated only for bisexual people (AOR = 2.91; 95% CI 1.80-4.72; and AOR = 1.63; 95% CI 1.03-2.57 respectively), whilst odds of illicit drug use remained unchanged. There were no interactions with age, gender, childhood sexual abuse, or religious identification. CONCLUSIONS: Mental health inequalities in non-heterosexuals have not narrowed, despite increasing societal acceptance. Bullying and discrimination may help explain the elevated rate of CMD in lesbian women and gay men but not in bisexual people

Boundary driven zero-range processes in random media

The stationary states of boundary driven zero-range processes in random media with quenched disorder are examined, and the motion of a tagged particle is analyzed. For symmetric transition rates, also known as the random barrier model, the stationary state is found to be trivial in absence of boundary drive. Out of equilibrium, two further cases are distinguished according to the tail of the disorder distribution. For strong disorder, the fugacity profiles are found to be governed by the paths of normalized $\alpha$-stable subordinators. The expectations of integrated functions of the tagged particle position are calculated for three types of routes.Comment: 23 page

Levy-Student Distributions for Halos in Accelerator Beams

We describe the transverse beam distribution in particle accelerators within the controlled, stochastic dynamical scheme of the Stochastic Mechanics (SM) which produces time reversal invariant diffusion processes. This leads to a linearized theory summarized in a Shchr\"odinger--like (\Sl) equation. The space charge effects have been introduced in a recent paper~\cite{prstab} by coupling this \Sl equation with the Maxwell equations. We analyze the space charge effects to understand how the dynamics produces the actual beam distributions, and in particular we show how the stationary, self--consistent solutions are related to the (external, and space--charge) potentials both when we suppose that the external field is harmonic (\emph{constant focusing}), and when we \emph{a priori} prescribe the shape of the stationary solution. We then proceed to discuss a few new ideas~\cite{epac04} by introducing the generalized Student distributions, namely non--Gaussian, L\'evy \emph{infinitely divisible} (but not \emph{stable}) distributions. We will discuss this idea from two different standpoints: (a) first by supposing that the stationary distribution of our (Wiener powered) SM model is a Student distribution; (b) by supposing that our model is based on a (non--Gaussian) L\'evy process whose increments are Student distributed. We show that in the case (a) the longer tails of the power decay of the Student laws, and in the case (b) the discontinuities of the L\'evy--Student process can well account for the rare escape of particles from the beam core, and hence for the formation of a halo in intense beams.Comment: revtex4, 18 pages, 12 figure

Elementary derivation of Spitzer's asymptotic law for Brownian windings and some of its physical applications

A simple derivation of Spitzer'z asymptotic law for Brownian windings [Trans.Am.Math.Soc.87,187 (1958)]is presented along with its generalizations >.These include the cases of planar Brownian walks interacting with a single puncture and Brownian walks on a single truncated cone with variable conical angle interacting with the truncated conical tip.Such situations are typical in the theories of quantum Hall effect and 2+1 quantum gravity, respectively .They also have some applications in polymer physic