169 research outputs found

    Demersal predator exposure to toxic organic contaminants: Direct effects of macrofauna in trophic transfer

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    The bioaccumulation and metabolism of organic contaminants (PAH, PCB) by three estuarine polychaetes, Nereis succinea (Frey and Leuckart 1847), Paraprionospio pinnata (Ehlers 1901) and Polydora ligni (Webster 1879), and by the fish predator, spot (Leiostomus xanthurus Lacepede 1802), were examined in laboratory experiments. Variations in trophic transfer of these contaminants resulting from differences in prey and contaminant type were also investigated. Toxicokinetic modeling reveals that metabolism of organic contaminants by invertebrate species result in variations in uptake, metabolism and elimination rate constants. Incorporation of prey metabolism potential in kinetic models increases the latter\u27s predictability of biota-sediment accumulation factors (BSAFs), or the net result of uptake and elimination processes. With organisms that have moderate to high metabolic capabilities and slow metabolite elimination, high rates of metabolite formation will significantly underestimate the uptake clearance rate constant and BSAFs, and the models will have low predictive capabilities. Assimilation efficiency of organic contaminants by spot varies with prey type, metabolism and size; contaminant type; and is independent of prey concentration at low contaminant concentrations. Furthermore, toxicokinetic modeling indicate that there are significant differences in uptake and metabolism formation rate constants by spot due to variations in the metabolite content of its food, and significant differences in elimination rates between spot tissues and contaminant types. In addition, aqueous soluble metabolites from prey were less available to predators, and dietary accumulation factors are reduced with contaminant metabolism. The metabolic responses by organisms to toxic organic contaminants must be considered in toxicokinetic modeling, and knowledge of benthic invertebrate prey species metabolism can be used to increase the predictability of BSAF. The metabolism potential of both the prey and contaminant is therefore important in the long term, integrated process of trophic transfer. Differences in prey contaminant forms and concentrations will strongly influence the trophic transfer of organic contaminants. Predator diet will strongly influence its contaminant exposure and possible effects through preconsumptive metabolism of organic contaminants by prey. These results have important implications for modeling organic contaminant trophic transfer and fate in estuarine and coastal systems

    Responding to natural disasters: Examining identity and prosociality in the context of a major earthquake

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    How does a major natural disaster relate to individuals’ orientation towards society? We collected repeated cross‐sectional surveys before (n = 644) and after the 2010 Chile earthquake (n = 1,389) to examine levels of national identity, prosocial values, helping motivations, and prosocial behaviours in the context of such a calamitous societal event. Our research questions, derived from the literature on helping in times of crisis, considered how natural disasters may implicate identity and prosociality, as well as how identity, prosocial values, and motivations are linked to prosocial action after a disaster. Higher levels of national identity, helping motivations, and disaster‐related helping were found after the earthquake, suggesting that in the aftermath of a disaster, people unite under a common national identity and are motivated to take action related to disaster relief. National identity and prosocial values were closely linked to helping after the earthquake, but specific helping motivations rarely predicted prosocial behaviours. Additionally, proximity to the epicentre was related to higher levels of national identity and participation in reconstruction efforts. These findings contribute to our understanding of people's responses to natural disasters and suggest ways of encouraging prosocial behaviour in the aftermath of unexpected tragic events

    Entwurf eines Objektmodells für semistrukturierte Daten im Kontext von XML Content Management Systemen

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    Seit einigen Jahren werden zur Erstellung und Pflege umfangreicher Websites vornehmlich Content Management Systeme (CMS) eingesetzt. Die überwiegende Entwicklungsarbeit wurde bei diesen Systemen in immer mächtigere Templatesprachen und aufwändigere Benutzeroberflächen investiert. Aspekte, die das zugrunde liegende Datenmodell betreffen, wurden dabei allerdings vernachlässigt: zumeist wird mehr oder weniger direkt auf eine Datenbank zugegriffen. Ziel der vorliegenden Arbeit ist der Entwurf einer auf die CMS-Aufgabenstellung ausgerichteten Architektur, deren Datenmodell zusammen mit einer darauf abgestimmten Templatesprache die Entwicklung neuer Webangebote effizienter und einfacher machen kann. Zunächst werden die Anforderungen an ein Datenmodell für CMS erarbeitet. Darauf basierend wird ein objektorientiertes Modell entwickelt und mittels einer formalen Semantikbeschreibung definiert. Das Modell unterstützt inhärent die typischen hierarchischen Strukturen von Websites. Vererbung ist durch Verwendung einer speziellen Form der Familienpolymorphie sowohl zwischen einzelnen Klassen als auch zwischen kompletten Webanwendungen möglich. Ein Entwickler kann große Teile von vorhandenem Code auf dem Wege der Vererbung wiederverwenden. Eine Zerlegung von Objekten in feingranulare Bestandteile ermöglicht eine weitere Reduzierung von Redundanzen bei der Modellierung. Als Bindeglied zwischen Daten und publizierten Dokumenten haben sich Templates bewährt. Eine Analyse der Anforderungen und vorhandenen Ansätze führt zu der Entscheidung für eine funktionale Templatesprache. Diese Templatesprache und die Beschreibung des objektorientierten Datenmodells werden zu einer einheitlichen Sprache integriert, die zudem durch die die Einbindung von XML die Ausgabe in unterschiedlichen Dokumentenformaten unterstützt.Design of an object model for semistructured data in context of XML content management systems For several years, mostly Content Management Systems (CMS) are used for the creation and maintenance of large web sites. Most of the development effort of these systems has been put in more sophisticated template languages und complex user interfaces. Aspects regarding the underlying data model have been neglected though: the database is accessed more or less directly in most cases. The goal of the present thesis is the design of an architecture which is attuned to the tasks of CMS, the data model of which together with a template language can make the development of new web sites more efficient and easier. At first, the requirements on a data model for CMS are compiled. Thereupon an object-oriented model is developed and defined by means of a formal semantic description. This model inherently supports the typical hierarchical structures of websites. Inheritance is possible between single classes as well as between entire web applications by utilizing a special kind of family polymorphism. A developer can re-use large parts of existing code through inheritance. Moreover, a decomposition of objects into fine-grained parts allows the reduction of redundancies in modelling. Templates have proved as the crucial link between data and published pages. An analysis of requirements and existing approaches leads to the decision for a functional template language. This template language and the description of the objekt-oriented data model are integrated into a uniform language which furthermore supports the output in different document formats by integrating XML

    TECHNICAL REPORT: Rapid confirmation of gene targeting in embryonic stem cells using two long-range PCR techniques

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    Gene targeting in mouse embryonic stem (ES) cells generally includes the analysis of numerous colonies to identify a few with mutations resulting from homologous recombination with a targeting vector. Thus, simple and efficient screening methods are needed to identify targeted clones. Optimal screening approaches require probes from outside of the region included in the targeting vector to avoid detection of the more common random insertions. However, the use of large genomic fragments in targeting vectors can limit the availability of cloned DNA, thus necessitating a strategy to obtain unique flanking sequences. We describe a rapid method to identify sequences adjacent to cloned DNA using long-range polymerase chain reaction (PCR) amplification from a genomic DNA library, followed by direct nucleotide sequencing of the amplified fragment. We have used this technique in two independent gene targeting experiments to obtain genomic DNA sequences flanking the mouse cholecystokinin (CCK) and gastrin genes. The sequences were then used to design primers to characterize ES cell lines with CCK or gastrin targeted gene mutations, employing a second long-range PCR approach. Our results show that these two long-range PCR methods are generally useful to rapidly and accurately characterize allele structures in ES cellsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43859/1/11248_2004_Article_172516.pd

    The fate of the 2√3 × 2√3R(30°) silicene phase on Ag(111)

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    Silicon atoms deposited on Ag(111) produce various single layer silicene sheets with different buckling patterns and periodicities. Low temperature scanning tunneling microscopy reveals that one of the silicene sheets, the hypothetical √7 × √7 silicene structure, on 2√3 × 2√3 Ag(111), is inherently highly defective and displays no long-range order. Moreover, Auger and photoelectron spectroscopy measurements reveal its sudden death, to end, in a dynamic fating process at ∼300 °C. This result clarifies the real nature of the 2√3 × 2√3R(30°) silicene phase and thus helps to understand the diversity of the silicene sheets grown on Ag(111)

    Tendances de la tuberculose pulmonaire bactériologiquement confirmée et issues thérapeutiques en République Démocratique du Congo : 2007-2017: Trends of bacteriologically confirmed pulmonary tuberculosis and treatment outcomes in Democratic Republic of the Congo: 2007-2017

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    Context and objective. DR Congo ranks among high burden countries for tuberculosis. However, the real incidence of the disease is unknown. The study aimed to describe the trends in the estimated incidence of the bacteriologically confirmed pulmonary TB and therapeutic outcomes of patients. Methods. A retrospective analysis of data from TB patients recorded during the period of 2007 to 2017 through all the country. Linear regtression model and z-score helped to assess the year to year variations in notification rate and treatment outcomes. Results. A total of 884,458 patients were enrolled including 820,858 new patients (NP TP+) and 63,600 with a previous TB treatment. The increase reached 28.95% during this decade. The annual average inrease was of 2, 41% +/- 3, and 28 % for NP TP+ and of 5, 7% +/-0.26 for default patients. Treatment outcome assessment included 848,163 patients among them, 789, 716 NP TP+ and 58,447 with a previous TB treatment. The success rate was 88% in the former group, of 70% in those with relapse, 64.3% in patients with failure and 67.8% in the group of ancient defaulters. A total of 70,515 (8.3%) patients remained smear positive. Conclusion. The study shows an increase in the incidence of reported TP+ patients with a treatment outcome reaching the WHO’s expectations. However the high proportion of smear positive patients suggests a high risk of further acquired TB resistance. Contexte et objectifs. La République Démocratique du Congo compte parmi les pays à lourd fardeau pour la tuberculose (TB), l’incidence réelle de la maladie n’est pas formellement connue. La présente étude vise à décrire les tendances de l’incidence notifiée des patients atteints de tuberculose pulmonaire bactériologiquement confirmée (TP+) et leurs issues thérapeutiques. Méthodes. Cette étude documentaire, analyse les données des patients diagnostiqués et traités pour tuberculose de 2007 à 2017 en RDC. L’incidence notifiée des patients TP+, le taux d’accroissement annuel, les issues thérapeutiques ont été recherchés. Les variations du nombre de patients sont exprimées par les proportions. Les tendances sont présentées à travers les courbes de régression linéaire. Les issues thérapeutiques sont comparées à l’aide du z-score avec un seuil significatif de p˂ 0,05. Résultats. Au total 884 458 patients TP+ ont été rapportés, dont 820 858 nouveaux patients (NP TP+) et 63 600 déjà traités. Le taux d’accroissement au cours de cette décade était de 28,95%, soit de 66099 en 2007 à 93767 en 2017 pour les NP TP+. L’augmentation annuelle moyenne était de 2,41% +/- 3,28 pour les NP TP+ et de 5,7% +/- 0,26 par an pour les rechutes. La notification des échecs de traitement initial et repris après abandon de traitement ont une tendance à la baisse. L’évaluation thérapeutique de tous les cas cumulés a concerné 848 163 patients dont 789 716 NP TP+ et 58447 en retraitement. Le succès thérapeutique était de 88,0 % pour les NP TP+ et 70,0 % pour les rechutes, de 64,3 % pour les échecs et de 67,8% pour les repris en traitement après abandon. En somme 70 515 (8,3%) patients ont gardé des expectorations positives. Conclusion. Cette étude montre une tendance à la hausse de notification des cas incidents dont l’issue de traitement répond aux standards de l’OMS. En outre, un nombre des personnes demeurent porteurs de germes persistants précurseurs d’une TB pharmacorésistante acquise

    A Precisely Regulated Gene Expression Cassette Potently Modulates Metastasis and Survival in Multiple Solid Cancers

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    Successful tumor development and progression involves the complex interplay of both pro- and anti-oncogenic signaling pathways. Genetic components balancing these opposing activities are likely to require tight regulation, because even subtle alterations in their expression may disrupt this balance with major consequences for various cancer-associated phenotypes. Here, we describe a cassette of cancer-specific genes exhibiting precise transcriptional control in solid tumors. Mining a database of tumor gene expression profiles from six different tissues, we identified 48 genes exhibiting highly restricted levels of gene expression variation in tumors (n = 270) compared to nonmalignant tissues (n = 71). Comprising genes linked to multiple cancer-related pathways, the restricted expression of this “Poised Gene Cassette” (PGC) was robustly validated across 11 independent cohorts of ∼1,300 samples from multiple cancer types. In three separate experimental models, subtle alterations in PGC expression were consistently associated with significant differences in metastatic and invasive potential. We functionally confirmed this association in siRNA knockdown experiments of five PGC genes (p53CSV, MAP3K11, MTCH2, CPSF6, and SKIP), which either directly enhanced the invasive capacities or inhibited the proliferation of AGS cancer cells. In primary tumors, similar subtle alterations in PGC expression were also repeatedly associated with clinical outcome in multiple cohorts. Taken collectively, these findings support the existence of a common set of precisely controlled genes in solid tumors. Since inducing small activity changes in these genes may prove sufficient to potently influence various tumor phenotypes such as metastasis, targeting such precisely regulated genes may represent a promising avenue for novel anti-cancer therapies

    Simultaneous analysis of the elastic scattering and breakup channel for the reaction 11 Li + 208 Pb at energies near the Coulomb barrier

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    We present a detailed analysis of the elastic scattering and breakup channel for the reaction of Li11 on Pb208 at incident laboratory energies of 24.3 and 29.8 MeV, measured at the radioactive ion beam facility of TRIUMF, in Vancouver, Canada. A large yield of Li9 fragments was detected by four charged particle telescopes in a wide angular range. The experimental angular and energy distributions of these Li9 fragments have been compared to coupled-reaction-channel and continuum-discretized coupled-channel calculations. The large production of Li9 fragments at small angles can be explained by considering a direct breakup mechanism, while at medium-large angles a competition between direct breakup and neutron transfer to the continuum of the Pb208 target was observed.Proyecto Nacional (España) PA2009-08848 PA2009-07387 PA2010-22131-C02-01 FPA2009-07653 FPA2012-32443Programa Consolider-Ingenio 2010 (España) CSD2007-0004

    Emotional reactions to involuntary psychiatric hospitalization and stigma-related stress among people with mental illness

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    Compulsory admission to psychiatric inpatient treatment can be experienced as disempowering and stigmatizing by people with serious mental illness. However, quantitative studies of stigma-related emotional and cognitive reactions to involuntary hospitalization and their impact on people with mental illness are scarce. Among 186 individuals with serious mental illness and a history of recent involuntary hospitalization, shame and self-contempt as emotional reactions to involuntary hospitalization, the cognitive appraisal of stigma as a stressor, self-stigma, empowerment as well as quality of life and self-esteem were assessed by self-report. Psychiatric symptoms were rated by the Brief Psychiatric Rating Scale. In multiple linear regressions, more self-stigma was predicted independently by higher levels of shame, self-contempt and stigma stress. A greater sense of empowerment was related to lower levels of stigma stress and self-contempt. These findings remained significant after controlling for psychiatric symptoms, diagnosis, age, gender and the number of lifetime involuntary hospitalizations. Increased self-stigma and reduced empowerment in turn predicted poorer quality of life and reduced self-esteem. The negative effect of emotional reactions and stigma stress on quality of life and self-esteem was largely mediated by increased self-stigma and reduced empowerment. Shame and self-contempt as reactions to involuntary hospitalization as well as stigma stress may lead to self-stigma, reduced empowerment and poor quality of life. Emotional and cognitive reactions to coercion may determine its impact more than the quantity of coercive experiences. Interventions to reduce the negative effects of compulsory admissions should address emotional reactions and stigma as a stressor
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