Three-dimensional view of ultrafast dynamics in photoexcited bacteriorhodopsin in the multiphoton regime and biological relevance

How does chemistry scale in complexity to unerringly direct biological functions? Nass Kovacs et al. have shown that bacteriorhodopsin undergoes structural changes tantalizingly similar to the expected pathway even under excessive excitation. Is the protein structure so highly evolved that it directs all deposited energy into the designed function

Les expériences vécues par les enfants de Duplessis institutionnalisés : les conséquences après plus de 50 ans

Dans cet article, les auteurs présentent les résultats qualitatifs recueillis à partir de questionnaires et d’entrevues semi-structurées destinés à documenter les expériences tant actuelles que passées des enfants de Duplessis institutionnalisés (EDI). Des exemples typiques et deux cas représentatifs sont présentés. Les résultats indiquent que les abus et la négligence subis par les EDI pendant l’enfance ont compromis leur ajustement psychosocial à long terme. Ils révèlent aussi que les EDI qui ont rapporté au moins quatre forces pendant leur enfance étaient plus susceptibles d’être protégés à l’âge adulte contre les effets négatifs de leur placement.In this article, the authors present qualitative results, derived from questionnaires and semi-structured interviews, to describe past and present experiences of the Duplessis children. Examples representative of their experience and a detailed description of two cases are provided. Results indicate that childhood abuse and negligence are related to poorer long-term psychological adjustment. The findings also demonstrate that reporting at least four strengths in childhood can have long-term protective effects.En este artículo, los autores presentan los resultados cualitativos recopilados a partir de cuestionarios y entrevistas semiestructuradas destinadas a documentar las experiencias, tanto recientes como pasadas, de los niños de Duplessis que fueron institucionalizados (EDI). Se presentan ejemplos típicos y dos casos representativos. Los resultados indican que los abusos y la negligencia sufridos por los EDI durante la infancia han comprometido su ajuste psicosocial a largo plazo. También revelan que los EDI que han reportado al menos cuatro fuerzas durante su infancia eran más susceptibles de estar protegidos en la edad adulta contra los efectos negativos de su colocación.Neste artigo, os autores apresentam os resultados qualitativos coletados a partir de questionários e entrevistas semi-estruturadas destinados a documentar as experiências tanto atuais quanto passadas das crianças de Duplessis institucionalizadas (CDI). São apresentados exemplos típicos e dois casos representativos. Os resultados indicam que os abusos e a negligência sofridos pelas CDI durante a infância comprometeram seu ajuste psicossocial a longo prazo. Eles revelam também que as CDI que relataram, pelo menos, quatro aspectos positivos durante sua infância eram mais susceptíveis de ser protegidas durante a idade adulta contra os efeitos negativos de sua internação

Répercussions d’une enfance vécue en institution : le cas des Enfants de Duplessis

Les conséquences négatives d’un placement en institution sur les enfants ont été documentées, mais aucune étude n’a porté sur les orphelins et les enfants placés une fois devenus adultes. Au Québec, les Enfants de Duplessis offrent un témoignage poignant des répercussions à long terme d’une enfance vécue en institution. Les histoires recueillies auprès de 40 hommes et 41 femmes ayant grandi en institution à l’époque de Duplessis font état d’un nombre élevé d’abus et d’expériences adverses, incluant les agressions physiques, psychologiques et sexuelles. Le milieu était peu stimulant et offrait peu d’opportunités de développer des relations d’attachement positives et significatives. Lorsqu’ils sont appariés et comparés à des adultes provenant de l’enquête Santé-Québec, les Enfants de Duplessis devenus adultes rapportent plus de problèmes de santé liés au stress et une détresse psychologique plus importante. Nos résultats indiquent également que les personnes ayant disposé de peu de ressources et d’aptitudes personnelles dans l’enfance sont les plus affectées par les expériences adverses.Whereas the immediate consequences of institutionalized placements on children have been documented, no study has investigated adults who were raised in orphanages or institutions. In Quebec, les enfants de Duplessis offer a unique testimony of the long term consequences of an institutionalized childhood. Stories collected from 40 men and 41 women who grew up in institution in Duplessis’era indicate a high number of abuse and aversive experiences, including physical, psychological and sexual aggressions. In addition, the environment was poor in stimulation and opportunities to develop positive attachment relationships with adults. When matched and compared to adults from the Santé-Québec survey, les enfants de Duplessis report a higher number of health problems associated with stress and more psychological distress. Moreover, our results indicate that those who had fewer strengths and aptitudes in childhood are the most affected by unfavourable experiences.Se han documentado las consecuencias negativas del ingreso de los niños a una institución, pero ningún estudio trata acerca de los adultos que fueron internados cuando eran niños o quedaron huérfanos. En Quebec los niños de Duplessis son un testimonio desgarrador de las repercusiones a largo plazo de una infancia vivida en una institución. Las historias recopiladas de 40 hombres y 41 mujeres que crecieron en una institución en la época de Duplessis constatan el número elevado de abusos y experiencias adversas, incluyendo agresiones físicas, psicológicas y sexuales. El medio era poco estimulante y ofrecía pocas oportunidades de desarrollar relaciones de apego positivas y significativas. Al emparejarlos y compararlos a los adultos provenientes de la encuesta de Salud Quebec, los niños de Duplessis, quienes ya son adultos, reportan más problemas de salud relacionados al estrés y un desasosiego psicológico más importante. Nuestros resultados indican también que las personas que disponen de pocos recursos y aptitudes personales en su infancia son las más afectadas por las experiencias adversas.As conseqüências negativas de uma internação em instituição sobre as crianças foram documentadas, mas nenhum estudo foi realizado sobre os órfãos e as crianças internadas quando já se tornaram adultas. No Quebec, as “crianças de Duplessis” testemunham de maneira profunda das repercussões a longo prazo de uma infância vivida em instituição. As histórias recolhidas junto a 40 homens e 41 mulheres que cresceram em instituição na época do governo de Duplessis relatam um alto número de abusos e de experiências adversas, incluindo agressões físicas, psicológicas e sexuais. O meio era pouco estimulante e oferecia poucas oportunidades de desenvolver relações de apego positivas e significativas. Quando eles foram colocados lado a lado e comparados aos adultos vindos da pesquisa de Santé-Québec, as “crianças de Duplessis” que se tornaram adultas sofrem mais de problemas de saúde ligados ao estresse e a uma depressão psicológica mais importante. Nossos resultados indicam igualmente que as pessoas que dispuseram de poucos recursos e aptidões pessoais na infância são mais afetadas pelas experiências adversas

Slope of the intracranial pressure waveform after traumatic brain injury.

BackgroundThe measurement and treatment of ICP within the management of TBI generally focuses on keeping the mean ICP to less than 20 mm Hg. More sophisticated analysis of the intracranial pressure waveform has yielded important relationships, but those methods have not gained widespread use. Prior analysis of the slope of the ICP waveform during inspiration and expiration in patients with hydrocephalus has provided valuable information that has never been applied to patients with TBI. This study used digital methods to examine ICP and the slope of the ICP waveform in relation to the respiratory cycle in subjects with TBI.MethodsIntracranial pressure was monitored in 6 randomly selected patients admitted with acute TBI. In the first 3 subjects, a single 5-minute recording was analyzed. In 3 subsequent subjects, 4 nonsequential 5-minute epochs were analyzed during periods of varying ICP. The systolic slope of the ICP waveform was compared during inspiration and expiration, and then evaluated in relation to simultaneous mean ICP.ResultsThe slope of the systolic ICP waveform was significantly greater during inspiration than during expiration (P < .0001 for 5 subjects and P < .03 for 1 subject). Within each subject, the ICP slope was positively correlated with simultaneous ICP (P < .0001 in all 6 cases).ConclusionGreater systolic ICP waveform slope during inspiration has not been described previously after TBI and is consistent with prior observations in subjects with hydrocephalus. The strong correlation between ICP slope and simultaneous mean ICP suggests that increasing ICP slope might indicate loss of intracranial compliance after TBI

Detection of subthreshold pulses in neurons with channel noise

Neurons are subject to various kinds of noise. In addition to synaptic noise, the stochastic opening and closing of ion channels represents an intrinsic source of noise that affects the signal processing properties of the neuron. In this paper, we studied the response of a stochastic Hodgkin-Huxley neuron to transient input subthreshold pulses. It was found that the average response time decreases but variance increases as the amplitude of channel noise increases. In the case of single pulse detection, we show that channel noise enables one neuron to detect the subthreshold signals and an optimal membrane area (or channel noise intensity) exists for a single neuron to achieve optimal performance. However, the detection ability of a single neuron is limited by large errors. Here, we test a simple neuronal network that can enhance the pulse detecting abilities of neurons and find dozens of neurons can perfectly detect subthreshold pulses. The phenomenon of intrinsic stochastic resonance is also found both at the level of single neurons and at the level of networks. At the network level, the detection ability of networks can be optimized for the number of neurons comprising the network.Comment: 14 pages, 9 figure

The distribution and movement patterns of four woodland caribou herds in Quebec and Labrador

Recent studies of woodland caribou (Rangifer tarandus caribou) in northern Quebec and central Labrador have demonstrated similar patterns of seasonal movements and distribution among four herds. Aerial surveys and radio-telemetry indicated that animals occupied forest-wetland habitat at densities of 0.03 caribou km2, or lower, for most of the year. Although females were widely dispersed at calving individuals demonstrated fidelity toward specific calving locations, in successive years. Caribou did not form large post-calving aggregations. Movement was greatest in the spring, prior to calving, and in the fall, during or immediately after rutting. Caribou were generally sedentary during summer and winter, although some moved relatively long distances to late-winter range. Although the herds occupy continuous range across Quebec and Labrador, our data indicate that the herds are largely discreete and should be managed individually

Detection of Atmospheric Cherenkov Radiation Using Solar Heliostat Mirrors

The gamma-ray energy region between 20 and 250 GeV is largely unexplored. Ground-based atmospheric Cherenkov detectors offer a possible way to explore this region, but large Cherenkov photon collection areas are needed to achieve low energy thresholds. This paper discusses the development of a Cherenkov detector using the heliostat mirrors of a solar power plant as the primary collector. As part of this development, we built a prototype detector consisting of four heliostat mirrors and used it to record atmospheric Cherenkov radiation produced in extensive air showers created by cosmic ray particles.Comment: 16 latex pages, 8 postscript figures, uses psfig.sty, to be published in Astroparticle Physic

Cannabis use and risk of schizophrenia: a Mendelian randomization study.

Cannabis use is observationally associated with an increased risk of schizophrenia, but whether the relationship is causal is not known. Using a genetic approach, we took 10 independent genetic variants previously identified to associate with cannabis use in 32 330 individuals to determine the nature of the association between cannabis use and risk of schizophrenia. Genetic variants were employed as instruments to recapitulate a randomized controlled trial involving two groups (cannabis users vs nonusers) to estimate the causal effect of cannabis use on risk of schizophrenia in 34 241 cases and 45 604 controls from predominantly European descent. Genetically-derived estimates were compared with a meta-analysis of observational studies reporting ever use of cannabis and risk of schizophrenia or related disorders. Based on the genetic approach, use of cannabis was associated with increased risk of schizophrenia (odds ratio (OR) of schizophrenia for users vs nonusers of cannabis: 1.37; 95% confidence interval (CI), 1.09-1.67; P-value=0.007). The corresponding estimate from observational analysis was 1.43 (95% CI, 1.19-1.67; P-value for heterogeneity =0.76). The genetic markers did not show evidence of pleiotropic effects and accounting for tobacco exposure did not alter the association (OR of schizophrenia for users vs nonusers of cannabis, adjusted for ever vs never smoker: 1.41; 95% CI, 1.09-1.83). This adds to the substantial evidence base that has previously identified cannabis use to associate with increased risk of schizophrenia, by suggesting that the relationship is causal. Such robust evidence may inform public health messages about cannabis use, especially regarding its potential mental health consequences

The Cosmic Ray Background as a Tool for Relative Calibration of Atmospheric Cherenkov Telescopes

The atmosphere is an intrinsic part of any ground based Cherenkov gamma-ray telescope, and the telescope response is therefore sensitive to unpredictable changes in the atmospheric transparency which are difficult to measure and interpret in the absence of a calibrated beam of high energy gamma-rays. In this paper, we use the detector response to Cherenkov emission from cosmic ray initiated air showers to obtain a relative calibration for data obtained under different instrumental and atmospheric conditions as well as over a range of source angles to the Zenith. We show that such a relative calibration is useful and efficient for data selection, for correcting the measured gamma-ray rate and for inter-calibration between the elements of an array of Cherenkov telescopes.Comment: 19 pages. Accepted for publication in Astroparticle Physic