Suicide Prevention for Older Adults in Residential Communities: Implications for Policy and Practice

Examining an often under-appreciated area, Carol Podgorski and colleagues discuss the suicide risk and opportunities for suicide prevention in seniors' residential communities

Gender differences in outcomes in people with schizophrenia in rural China: 14-year follow-up study

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Snapshot Provisioning of Cloud Application Stacks to Face Traffic Surges

Traffic surges, like the Slashdot effect, occur when a web application is overloaded by a huge number of requests, potentially leading to unavailability. Unfortunately, such traffic variations are generally totally unplanned, of great amplitude, within a very short period, and a variable delay to return to a normal regime. In this report, we introduce PeakForecast as an elastic middleware solution to detect and absorb a traffic surge. In particular, PeakForecast can, from a trace of queries received in the last seconds, minutes or hours, to detect if the underlying system is facing a traffic surge or not, and then estimate the future traffic using a forecast model with an acceptable precision, thereby calculating the number of resources required to absorb the remaining traffic to come. We validate our solution by experimental results demonstrating that it can provide instantaneous elasticity of resources for traffic surges observed on the Japanese version of Wikipedia during the Fukushima Daiichi nuclear disaster in March 2011.Les pics de trafic, tels que l'effet Slashdot, apparaissent lorsqu'une application web doit faire face un nombre important de requêtes qui peut potentiellement entraîner une mise hors service de l'application. Malheureusement, de telles variations de traffic sont en général totalement imprévues et d'une grande amplitude, arrivent pendant une très courte période de temps et le retour à un régime normal prend un délai variable. Dans ce rapport, nous présentons PeakForecast qui est une solution intergicielle élastique pour détecter et absorber les pics de trafic. En particulier, PeakForecast peut, à partir des traces de requêtes reçues dans les dernières secondes, minutes ou heures, détecter si le système sous-jacent fait face ou non à un pic de trafic, estimer le trafic futur en utilisant un modèle de prédiction suffisamment précis, et calculer le nombre de ressources nécessaires à l'absorption du trafic restant à venir. Nous validons notre solution avec des résultats expérimentaux qui démontrent qu'elle fournit une élasticité instantanée des ressources pour des pics de trafic qui ont été observés sur la version japonaise de Wikipedia lors de l'accident nucléaire de Fukushima Daiichi en mars 2011

Hot-electron effect in spin dephasing in nn-type GaAs quantum wells

We perform a study of the effect of the high in-plane electric field on the spin precession and spin dephasing due to the D'yakonov-Perel' mechanism in $n$-type GaAs (100) quantum wells by constructing and numerically solving the kinetic Bloch equations. We self-consistently include all of the scattering such as electron-phonon, electron-non-magnetic impurity as well as the electron-electron Coulomb scattering in our theory and systematically investigate how the spin precession and spin dephasing are affected by the high electric field under various conditions. The hot-electron distribution functions and the spin correlations are calculated rigorously in our theory. It is found that the D'yakonov-Perel' term in the electric field provides a non-vanishing effective magnetic field that alters the spin precession period. Moreover, spin dephasing is markedly affected by the electric field. The important contribution of the electron-electron scattering to the spin dephasing is also discussed.Comment: 11 pages, 11 figures, accepted for publication in Phys. Rev.

Socio-economic and psychological correlates of suicidality among Hong Kong working-age adults: Results from a population-based survey

Background. The global toll of suicide is estimated to be one million lives per year, which exceeded the number of deaths by homicide and war combined. A key step to suicide prevention is to prevent less serious suicidal behaviour to preclude more lethal outcomes. Although 61% of the world's suicides take place in Asia and the suicide rates among middle age groups have been increasing since the economic crisis in many Asian countries, population-based studies of suicidal behaviour among working-age adults in non-western communities are scarce. Method. Data from a population-based survey with 2015 participants were used to estimate the prevalence of suicidal ideation and behaviour among the working-age population in Hong Kong, and to study the associated socio-economic and psychological correlates. We focused particularly on potential modulating factors between life-event-related factors and suicidal ideation. Results. Six per cent of the Hong Kong population aged 20-59 years considered suicide in the past year, while 1.4% attempted suicide. Hopelessness, reasons for living, and reluctance to seek help from family and friends had direct association with past-year suicidal ideation. Reasons for living were found to moderate the effect of perceived stress on suicidal ideation. Conclusions. Suicidality is a multi-faceted problem that calls for a multi-sectored, multi-layered approach to prevention. Prevention programmes can work on modulating factors such as reasons for living to reduce suicidal risk in working-age adults. © 2006 Cambridge University Press.published_or_final_versio

Mott-Peierls Transition in the extended Peierls-Hubbard model

The one-dimensional extended Peierls-Hubbard model is studied at several band fillings using the density matrix renormalization group method. Results show that the ground state evolves from a Mott-Peierls insulator with a correlation gap at half-filling to a soliton lattice with a small band gap away from half-filling. It is also confirmed that the ground state of the Peierls-Hubbard model undergoes a transition to a metallic state at finite doping. These results show that electronic correlations effects should be taken into account in theoretical studies of doped polyacetylene. They also show that a Mott-Peierls theory could explain the insulator-metal transition observed in this material.Comment: 4 pages with 3 embedded eps figure

Ferroelectrical spin wave resonance

New phenomenon is experimentally identified: ferroelectrical spin wave resonance (FE SWR), which consist in characteristic splitting of vibration (electronic-vibration) levels in optical spectra of interacting localized centers. Spectral positions of ESWR lines are determined in linear approach by quadratic dispersion law. It has been found that the values of resonance mode amplitudes are inversely proportional to mode numbers (by low excitation level). The prediction that Raman-ESWR and IR-ESWR are characterized by splitting constants with different values has been confirmed. Their ratio is approximately equal two (by the frequencies of zero modes reduced to the same value). It is independent argument for FE SWR identification.Comment: in russia

A Shot in the Dark: Failing to Recognize the Link Between Physical and Mental Illness

A 74-year-old widowed white man with chronic rheumatoid arthritis presented with nausea and weight loss. He was diagnosed with failure to thrive and admitted for hydration. Misoprostol was determined to be the etiology of his symptoms and he was discharged home. Three days later, he killed himself with a gunshot to the head. Clinicians often fail to recognize those at high risk for suicide. Suicidal risk is increased in both psychiatric and physical illness, and particularly when both are present. Psychiatric illness, particularly depression, often underlies chronic medical illness. The purpose of this case report is to remind health care providers of the strong association between depression and chronic medical illness, and to consider this in all patients, including those who present solely with physical symptoms. Recognizing this association and screening for it, as recommended by the U.S. Preventive Services Task Force, may prevent the unnecessary tragedy of suicide

Fluctuation-Facilitated Charge Migration along DNA

We propose a model Hamiltonian for charge transfer along the DNA double helix with temperature driven fluctuations in the base pair positions acting as the rate limiting factor for charge transfer between neighboring base pairs. We compare the predictions of the model with the recent work of J.K. Barton and A.H. Zewail (Proc.Natl.Acad.Sci.USA, {\bf 96}, 6014 (1999)) on the unusual two-stage charge transfer of DNA.Comment: 4 pages, 2 figure

Large scale numerical investigation of excited states in poly(phenylene)

A density matrix renormalisation group scheme is developed, allowing for the first time essentially exact numerical solutions for the important excited states of a realistic semi-empirical model for oligo-phenylenes. By monitoring the evolution of the energies with chain length and comparing them to the experimental absorption peaks of oligomers and thin films, we assign the four characteristic absorption peaks of phenyl-based polymers. We also determine the position and nature of the nonlinear optical states in this model.Comment: RevTeX, 10 pages, 4 eps figures included using eps