565 research outputs found

    Anisotropically Inflating Universes

    Full text link
    We show that in theories of gravity that add quadratic curvature invariants to the Einstein-Hilbert action there exist expanding vacuum cosmologies with positive cosmological constant which do not approach the de Sitter universe. Exact solutions are found which inflate anisotropically. This behaviour is driven by the Ricci curvature invariant and has no counterpart in the general relativistic limit. These examples show that the cosmic no-hair theorem does not hold in these higher-order extensions of general relativity and raises new questions about the ubiquity of inflation in the very early universe and the thermodynamics of gravitational fields.Comment: 5 pages, further discussion and references adde

    RĂ©percussions d’une enfance vĂ©cue en institution : le cas des Enfants de Duplessis

    Get PDF
    Les consĂ©quences nĂ©gatives d’un placement en institution sur les enfants ont Ă©tĂ© documentĂ©es, mais aucune Ă©tude n’a portĂ© sur les orphelins et les enfants placĂ©s une fois devenus adultes. Au QuĂ©bec, les Enfants de Duplessis offrent un tĂ©moignage poignant des rĂ©percussions Ă  long terme d’une enfance vĂ©cue en institution. Les histoires recueillies auprĂšs de 40 hommes et 41 femmes ayant grandi en institution Ă  l’époque de Duplessis font Ă©tat d’un nombre Ă©levĂ© d’abus et d’expĂ©riences adverses, incluant les agressions physiques, psychologiques et sexuelles. Le milieu Ă©tait peu stimulant et offrait peu d’opportunitĂ©s de dĂ©velopper des relations d’attachement positives et significatives. Lorsqu’ils sont appariĂ©s et comparĂ©s Ă  des adultes provenant de l’enquĂȘte SantĂ©-QuĂ©bec, les Enfants de Duplessis devenus adultes rapportent plus de problĂšmes de santĂ© liĂ©s au stress et une dĂ©tresse psychologique plus importante. Nos rĂ©sultats indiquent Ă©galement que les personnes ayant disposĂ© de peu de ressources et d’aptitudes personnelles dans l’enfance sont les plus affectĂ©es par les expĂ©riences 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 SantĂ©-QuĂ©bec 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 instituciĂłn, pero ningĂșn estudio trata acerca de los adultos que fueron internados cuando eran niños o quedaron huĂ©rfanos. En Quebec los niños de Duplessis son un testimonio desgarrador de las repercusiones a largo plazo de una infancia vivida en una instituciĂłn. Las historias recopiladas de 40 hombres y 41 mujeres que crecieron en una instituciĂłn en la Ă©poca de Duplessis constatan el nĂșmero elevado de abusos y experiencias adversas, incluyendo agresiones fĂ­sicas, psicolĂłgicas y sexuales. El medio era poco estimulante y ofrecĂ­a 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 mĂĄs problemas de salud relacionados al estrĂ©s y un desasosiego psicolĂłgico mĂĄs importante. Nuestros resultados indican tambiĂ©n que las personas que disponen de pocos recursos y aptitudes personales en su infancia son las mĂĄs afectadas por las experiencias adversas.As conseqĂŒĂȘncias negativas de uma internação em instituição sobre as crianças foram documentadas, mas nenhum estudo foi realizado sobre os ĂłrfĂŁos e as crianças internadas quando jĂĄ se tornaram adultas. No Quebec, as “crianças de Duplessis” testemunham de maneira profunda das repercussĂ”es a longo prazo de uma infĂąncia vivida em instituição. As histĂłrias recolhidas junto a 40 homens e 41 mulheres que cresceram em instituição na Ă©poca do governo de Duplessis relatam um alto nĂșmero de abusos e de experiĂȘncias adversas, incluindo agressĂ”es fĂ­sicas, psicolĂłgicas e sexuais. O meio era pouco estimulante e oferecia poucas oportunidades de desenvolver relaçÔes de apego positivas e significativas. Quando eles foram colocados lado a lado e comparados aos adultos vindos da pesquisa de SantĂ©-QuĂ©bec, as “crianças de Duplessis” que se tornaram adultas sofrem mais de problemas de saĂșde ligados ao estresse e a uma depressĂŁo psicolĂłgica mais importante. Nossos resultados indicam igualmente que as pessoas que dispuseram de poucos recursos e aptidĂ”es pessoais na infĂąncia sĂŁo mais afetadas pelas experiĂȘncias adversas

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

    Get PDF
    Dans cet article, les auteurs prĂ©sentent les rĂ©sultats qualitatifs recueillis Ă  partir de questionnaires et d’entrevues semi-structurĂ©es destinĂ©s Ă  documenter les expĂ©riences tant actuelles que passĂ©es des enfants de Duplessis institutionnalisĂ©s (EDI). Des exemples typiques et deux cas reprĂ©sentatifs sont prĂ©sentĂ©s. Les rĂ©sultats indiquent que les abus et la nĂ©gligence subis par les EDI pendant l’enfance ont compromis leur ajustement psychosocial Ă  long terme. Ils rĂ©vĂšlent aussi que les EDI qui ont rapportĂ© au moins quatre forces pendant leur enfance Ă©taient plus susceptibles d’ĂȘtre protĂ©gĂ©s Ă  l’ñge adulte contre les effets nĂ©gatifs 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 artĂ­culo, 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 tĂ­picos 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. TambiĂ©n revelan que los EDI que han reportado al menos cuatro fuerzas durante su infancia eran mĂĄs susceptibles de estar protegidos en la edad adulta contra los efectos negativos de su colocaciĂłn.Neste artigo, os autores apresentam os resultados qualitativos coletados a partir de questionĂĄrios e entrevistas semi-estruturadas destinados a documentar as experiĂȘncias tanto atuais quanto passadas das crianças de Duplessis institucionalizadas (CDI). SĂŁo apresentados exemplos tĂ­picos e dois casos representativos. Os resultados indicam que os abusos e a negligĂȘncia sofridos pelas CDI durante a infĂąncia comprometeram seu ajuste psicossocial a longo prazo. Eles revelam tambĂ©m que as CDI que relataram, pelo menos, quatro aspectos positivos durante sua infĂąncia eram mais susceptĂ­veis de ser protegidas durante a idade adulta contra os efeitos negativos de sua internação

    Dynamic Field Experiments in Development Economics: Risk Valuation in Morocco, Kenya, and Peru

    Get PDF
    The effective design and implementation of interventions that reduce vulnerability and poverty require a solid understanding of underlying poverty dynamics and associated behavioral responses. Stochastic and dynamic benefit streams can make it difficult for the poor to learn the value of such interventions to them. We explore how dynamic field experiments can help (i) intended beneficiaries to learn and understand these complicated benefit streams, and (ii) researchers to better understand how the poor respond to risk when faced with nonlinear welfare dynamics. We discuss and analyze dynamic risk valuation experiments in Morocco, Peru, and Kenya.poverty, risk and uncertainty, dynamics, experiments, Kenya, Morocco, Peru, International Development, Research Methods/ Statistical Methods, Risk and Uncertainty,

    Transduction of Non-Small Cell Lung Cancer Cells by Adenoviral and Retroviral Vectors

    Get PDF
    Gene transfer into a panel of non-small cell lung cancer (NSCLC) cells by adenoviral (Ad) and retroviral (RV) vectors was studied. Indexed to multiplicity of infection (MOI), Ad vectors transduce squamous, adenosquamous, and malignant mesothelioma cells with greater efficiency than large cells or adenocarcinoma cells. Transduction-sensitive cells bind the Ad vector with specificity for the Ad fiber knob, and internalize vector efficiently. Transduction-refractory cells bind and internalize vector by less efficient pathways. Like Ad vectors, there is heterogeneity in RV transduction efficiencies of different NSCLC subtypes. With respect to the most common cell type metastatic to the pleural space (adenocarcinoma), amphotropic retroviral vectors transduce cells of this subtype more efficiently (at a lower MOI) than Ad. RV transduction is not solely dependent on cellular replication, and both permissive and refractory cell lines express the mRNA for the amphotropic RV receptor. These observations suggest that neither Ad nor RV vectors will suffice a priori as the optimal gene transfer vehicle, and successful gene therapy of lung cancer may require tumor-specific or patient-specific vectors

    The Contribution of Accessory Toxins of Vibrio cholerae O1 El Tor to the Proinflammatory Response in a Murine Pulmonary Cholera Model

    Get PDF
    The contribution of accessory toxins to the acute inflammatory response to Vibrio cholerae was assessed in a murine pulmonary model. Intranasal administration of an El Tor O1 V. cholerae strain deleted of cholera toxin genes (ctxAB) caused diffuse pneumonia characterized by infiltration of PMNs, tissue damage, and hemorrhage. By contrast, the ctxAB mutant with an additional deletion in the actin-cross-linking repeats-in-toxin (RTX) toxin gene (rtxA) caused a less severe pathology and decreased serum levels of proinflammatory molecules interleukin (IL)-6 and murine macrophage inflammatory protein (MIP)-2. These data suggest that the RTX toxin contributes to the severity of acute inflammatory responses. Deletions within the genes for either hemagglutinin/protease (hapA) or hemolysin (hlyA) did not significantly affect virulence in this model. Compound deletion of ctxAB, hlyA, hapA, and rtxA created strain KFV101, which colonized the lung but induced pulmonary disease with limited inflammation and significantly reduced serum titers of IL-6 and MIP-2. 100% of mice inoculated with KFV101 survive, compared with 20% of mice inoculated with the ctxAB mutant. Thus, the reduced virulence of KFV101 makes it a prototype for multi-toxin deleted vaccine strains that could be used for protection against V. cholerae without the adverse effects of the accessory cholera toxins

    A Phylogenomic Study of the Genus Alphavirus Employing Whole Genome Comparison

    Get PDF
    The phylogenetics of the genus Alphavirus have historically been characterized using partial gene, single gene or partial proteomic data. We have mined cDNA and amino acid sequences from GenBank for all fully sequenced and some partially sequenced alphaviruses and generated phylogenomic analyses of the genus Alphavirus genus, employing capsid encoding structural regions, non-structural coding regions and complete viral genomes. Our studies support the presence of the previously reported recombination event that produced the Western Equine Encephalitis clade, and confirm many of the patterns of geographic radiation and divergence of the multiple species. Our data suggest that the Salmon Pancreatic Disease Virus and Sleeping Disease Virus are sufficiently divergent to form a separate clade from the other alphaviruses. Also, unlike previously reported studies employing limited sequence data for correlation of phylogeny, our results indicate that the Barmah Forest Virus and Middelburg Virus appear to be members of the Semliki Forest clade. Additionally, our analysis indicates that the Southern Elephant Seal Virus is part of the Semliki Forest clade, although still phylogenetically distant from all known members of the genus Alphavirus. Finally, we demonstrate that the whole Rubella viral genome provides an ideal outgroup for phylogenomic studies of the genus Alphavirus

    H1N1 2009 Pandemic Influenza Virus: Resistance of the I223R Neuraminidase Mutant Explained by Kinetic and Structural Analysis

    Get PDF
    Two classes of antiviral drugs, neuraminidase inhibitors and adamantanes, are approved for prophylaxis and therapy against influenza virus infections. A major concern is that antiviral resistant viruses emerge and spread in the human population. The 2009 pandemic H1N1 virus is already resistant to adamantanes. Recently, a novel neuraminidase inhibitor resistance mutation I223R was identified in the neuraminidase of this subtype. To understand the resistance mechanism of this mutation, the enzymatic properties of the I223R mutant, together with the most frequently observed resistance mutation, H275Y, and the double mutant I223R/H275Y were compared. Relative to wild type, KMvalues for MUNANA increased only 2-fold for the single I223R mutant and up to 8-fold for the double mutant. Oseltamivir inhibition constants (KI) increased 48-fold in the single I223R mutant and 7500-fold in the double mutant. In both cases the change was largely accounted for by an increased dissociation rate constant for oseltamivir, but the inhibition constants for zanamivir were less increased. We have used X-ray crystallography to better understand the effect of mutation I223R on drug binding. We find that there is shrinkage of a hydrophobic pocket in the active site as a result of the I223R change. Furthermore, R223 interacts with S247 which changes the rotamer it adopts and, consequently, binding of the pentoxyl substituent of oseltamivir is not as favorable as in the wild type. However, the polar glycerol substituent present in zanamivir, which mimics the natural substrate, is accommodate
    • 

    corecore