260 research outputs found

    Interference in interacting quantum dots with spin

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    We study spectral and transport properties of interacting quantum dots with spin. Two particular model systems are investigated: Lateral multilevel and two parallel quantum dots. In both cases different paths through the system can give rise to interference. We demonstrate that this strengthens the multilevel Kondo effect for which a simple two-stage mechanism is proposed. In parallel dots we show under which conditions the peak of an interference-induced orbital Kondo effect can be split.Comment: 8 pages, 8 figure

    Rural Population Health and Aging: Introduction to the Special Issue

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    This special issue of the Journal of Rural Social Sciences (JRSS) focuses on rural population health and aging. It showcases the work of scholars from several backgrounds and social science disciplines to advance knowledge in a critical field of investigation. Assembled through an open call for submissions coordinated through the National Institute on Aging (NIA) funded Interdisciplinary Network on Rural Population Health and Aging (INRPHA), the collection of articles helps inform a more nuanced understanding of the factors associated with rural places, which often have different health outcomes and aging patterns than their urban counterparts. The authors achieve this through application of innovative analytical strategies used with a combination of data sources. This introductory essay provides background and an overview of the four articles, followed by discussion of future opportunities to advance an agenda for rural population health and aging research

    Analyse der Hepatitis-C-Situation bei den drogenkonsumierenden Personen in der Schweiz

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    Die Analyse der Hepatitis-C-Situation bei den drogenkonsumierenden Personen in der Schweiz beruht auf verschiedenen Methoden: Analyse der publizierten und grauen Literatur zu diesem Thema, SekundĂ€ranalyse verfĂŒgbarer Daten, Befragung nationaler Fachpersonen, Befragung drogenkonsumierender Personen (DU), Fallstudien in vier Kantonen (ZĂŒrich, Waadt, Aargau, Wallis), Internetumfrage bei den Einrichtungen, die DU stationĂ€r oder ambulant behandeln, sowie bei den niederschwelligen Einrichtungen zur Risikominderung. In den vergangenen zwei Jahrzehnten erreichte die Zahl der neu gemeldeten Infektionen mit dem Hepatitis-C-Virus (HCV) Ende der 90er-Jahre eine Spitze mit mehr als 2500 FĂ€llen pro Jahr, wobei mehr als 30 % dieser FĂ€lle Personen betrafen, die intravenös Drogen konsumieren (IDU). Die Zahl neu gemeldeter FĂ€lle sank anschliessend bis auf 1500 FĂ€lle im Jahr 2011 und stieg dann wieder auf mehr als 1700 FĂ€lle im Jahr 2013 an. Der Anteil der IDU belief sich auf etwas mehr 20 % (436 FĂ€lle, kein Wiederanstieg der Anzahl neuer FĂ€lle in dieser Bevölkerungsgruppe). Die fĂŒr die Gesamtbevölkerung der Schweiz geschĂ€tzte PrĂ€valenz der HCV-Infektionen bewegt sich je nach Autor zwischen 0,7 % und 1,75 %. Bei MĂ€nnern, die Sex mit MĂ€nnern haben (MSM), ist dieser Wert etwas höher (2 %). Bei Staatsangehörigen aus LĂ€ndern mit einer höheren PrĂ€valenz (Afrika sĂŒdlich der Sahara, bestimmte LĂ€nder des Nahen Ostens und SĂŒdostasiens) ist die PrĂ€valenzrate vermutlich erhöht; es sind jedoch keine Werte bekannt. Auch in GefĂ€ngnissen ist die HCV-PrĂ€valenz höher als in der Gesamtbevölkerung, da DU und Staatsangehörige aus LĂ€ndern mit höherer PrĂ€valenz stĂ€rker vertreten sind (zwischen 5 und 10 %). Es wird davon ausgegangen, dass es bei etwa zwei Drittel der FĂ€lle zu einem chronischen Krankheitsverlauf kommt

    Analyse de la situation de l'hépatite C chez les usagers de drogue en Suisse

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    L'analyse de la situation de l'hĂ©patite C chez les usagers de drogue en Suisse a fait appel Ă  plusieurs mĂ©thodes: synthĂšse de la littĂ©rature publiĂ©e et grise sur le sujet et analyse secondaire de donnĂ©es disponibles, interviews d'experts nationaux, interviews d'usagers de drogues (UD), Ă©tudes de cas dans 4 cantons (Zurich, Vaud, Argovie, Valais), enquĂȘte par internet auprĂšs des institutions prenant en charge des UD en traitement rĂ©sidentiel et ambulatoire et dans les structures Ă  bas seuil d'accĂšs pour la rĂ©duction des risques. La prĂ©valence du VHC estimĂ©e sur l'ensemble de la population en Suisse varie selon les auteurs entre 0.7% et 1.75%. Elle est un peu plus Ă©levĂ©e (2%) chez les hommes ayant des relations sexuelles avec d'autres hommes (HSH). Chez les ressortissants de pays rĂ©putĂ©s Ă  plus haute prĂ©valence (Afrique sub-saharienne, certains pays du Moyen-Orient et d'Asie du Sud-Est), la prĂ©valence est probablement plus Ă©levĂ©e que dans la population gĂ©nĂ©rale mais n'est pas connue. En prison, du fait de la surreprĂ©sentation des UD et de populations de pays Ă  plus haute prĂ©valence, la prĂ©valence du VHC est plus Ă©levĂ©e que dans la population gĂ©nĂ©rale (entre 5 et 10%). On estime qu'environ 2/3 des cas vont Ă©voluer vers la chronicitĂ©..

    Werner syndrome protein limits MYC-induced cellular senescence - Supplementary Materials Only

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    The MYC oncoprotein is a transcription factor that coordinates cell growth and division. MYC overexpression exacerbates genomic instability and sensitizes cells to apoptotic stimuli. Here we demonstrate that MYC directly stimulates transcription of the human Werner syndrome gene, WRN, which encodes a conserved RecQ helicase. Loss-of-function mutations in WRN lead to genomic instability, an elevated cancer risk, and premature cellular senescence. The overexpression of MYC in WRN syndrome fibroblasts or after WRN depletion from control fibroblasts led to rapid cellular senescence that could not be suppressed by hTERT expression. We propose that WRN up-regulation by MYC may promote MYC-driven tumorigenesis by preventing cellular senescence

    Altered RECQ Helicase Expression in Sporadic Primary Colorectal Cancers

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    AbstractDeregulation of DNA repair enzymes occurs in cancers and may create a susceptibility to chemotherapy. Expression levels of DNA repair enzymes have been shown to predict the responsiveness of cancers to certain chemotherapeutic agents. The RECQ helicases repair damaged DNA including damage caused by topoisomerase I inhibitors, such as irinotecan. Altered expression levels of these enzymes in colorectal cancer (CRC) may influence the response of the cancers to irinotecan. Thus, we assessed RECQ helicase (WRN, BLM, RECQL, RECQL4, and RECQL5) expression in primary CRCs, matched normal colon, and CRC cell lines. We found that BLM and RECQL4 mRNA levels are significantly increased in CRC (P = .0011 and P < .0001, respectively), whereas RECQL and RECQL5 are significantly decreased (P = .0103 and P = .0029, respectively). RECQ helicase expression patterns varied between specific molecular subtypes of CRCs. The mRNA and protein expression of the majority of the RECQ helicases was closely correlated, suggesting that altered mRNA expression is the predominant mechanism for deregulated RECQ helicase expression. Immunohistochemistry localized the RECQ helicases to the nucleus. RECQ helicase expression is altered in CRC, suggesting that RECQ helicase expression has potential to identify CRCs that are susceptible to specific chemotherapeutic agents

    Looking for a needle in a haystack: inference about individual fitness components in a heterogeneous population

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    Studies of wild vertebrates have provided evidence of substantial differences in lifetime reproduction among individuals and the sequences of life history ‘states’ during life (breeding, nonbreeding, etc.). Such differences may reflect ‘fixed’ differences in fitness components among individuals determined before, or at the onset of reproductive life. Many retrospective life history studies have translated this idea by assuming a ‘latent’ unobserved heterogeneity resulting in a fixed hierarchy among individuals in fitness components. Alternatively, fixed differences among individuals are not necessarily needed to account for observed levels of individual heterogeneity in life histories. Individuals with identical fitness traits may stochastically experience different outcomes for breeding and survival through life that lead to a diversity of ‘state’ sequences with some individuals living longer and being more productive than others, by chance alone. The question is whether individuals differ in their underlying fitness components in ways that cannot be explained by observable ‘states’ such as age, previous breeding success, etc. Here, we compare statistical models that represent these opposing hypotheses, and mixtures of them, using data from kittiwakes. We constructed models that accounted for observed covariates, individual random effects (unobserved heterogeneity), first-order Markovian transitions between observed states, or combinations of these features. We show that individual sequences of states are better accounted for by models incorporating unobserved heterogeneity than by models including first-order Markov processes alone, or a combination of both. If we had not considered individual heterogeneity, models including Markovian transitions would have been the best performing ones. We also show that inference about age-related changes in fitness components is sensitive to incorporation of underlying individual heterogeneity in models. Our approach provides insight into the sources of individual heterogeneity in life histories, and can be applied to other data sets to examine the ubiquity of our results across the tree of life
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