993 resultados para Pitts, Adam,
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The decline in extent of wild pollinators in recent years has been partly associated with changing farm practices and in particular with increase of pesticide use. In this paper we combine ecological modelling with economic analysis of a single farm output under the assumption that both pollination and pest control are essential inputs. We show that the drive to increase farm output can lead to a local decline in the wild bee population. Commercial bees are often considered an alternative to wild pollinators, but we show that their introduction can lead to further decline and finally local extinction of wild bees. The transitions between different outcomes are characterised by threshold behaviour and are potentially difficult to predict and detect in advance. Small changes in economic (input prices) and ecological (wild bees carrying capacity and effect of pesticides on bees) can move the economic-ecological system beyond the extinction threshold. We also show that increasing the pesticide price or decreasing the commercial bee price might lead to reestablishment of wild bees following their local extinction. Thus, we demonstrate the importance of combining ecological modelling with economics to study the provision of ecosystem services and to inform sustainable management of ecosystem service providers.
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We re-examine the dynamics of returns and dividend growth within the present-value framework of stock prices. We find that the finite sample order of integration of returns is approximately equal to the order of integration of the first-differenced price-dividend ratio. As such, the traditional return forecasting regressions based on the price-dividend ratio are invalid. Moreover, the nonstationary long memory behaviour of the price-dividend ratio induces antipersistence in returns. This suggests that expected returns should be modelled as an AFIRMA process and we show this improves the forecast ability of the present-value model in-sample and out-of-sample.
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Los cuerpos artificiales ( muñecos, autómatas, maniquíes) son tratados a través de tres tipos de discurso: del artificio, de la mirada y del deseo. Esta perspectiva permite abordarlos, no como representaciones ni como dobles (Döppelgänger) sino como significantes en el discurso , como objetos de deseo y como puntos de articulación de la mirada. En el discurso del artificio se pasa revista al binomio natural/artificial y , a través de distintos textos , El tratado de Hombre de René Descarrtes, la “teoría de los maniquíes” y la “generatio aequivoca” de Bruno Schulz, y el film Jidlo (Comida) de Jan Svankmajer, se hace lo propio con los paradigmas desde los que se ha metaforizado al cuerpo humano. En el discurso de la mirada, se los aborda desde la perspectiva psicoanalítica del campo escópico, a través de El hombre de la arena, de ETA Hoffmann. Los discursos del deseo tratan de algunos aspectos de esta pulsión : el deseo masculino desde La Eva futura de Villiers de l’Isle Adam, el “deseo de hijo”, a través del film Otesánek de Jan Svankmajer y la genericidad del deseo en dos novelas de Gaston Leroux , La muñeca sangrienta y la máquina de asesinar . Los cuerpos artificiales, así, podrían ser considerados, en su potencia significativa, no ya como dobles , sino como efectos de lo real, como “pequeños otros”, como “objetos a” lacanianos y como simulacros.
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Collagen is highly conserved across species and has been used extensively for tissue regeneration; however, its mechanical properties are limited. A recent advance using plastic compression of collagen gels to achieve much higher concentrations significantly increases its mechanical properties at the neo-tissue level. This controlled, cell-independent process allows the engineering of biomimetic scaffolds. We have evaluated plastic compressed collagen scaffolds seeded with human bladder smooth muscle cells inside and urothelial cells on the gel surface for potential urological applications. Bladder smooth muscle and urothelial cells were visualized using scanning electron microscopy, conventional histology and immunohistochemistry; cell viability and proliferation were also quantified for 14 days in vitro. Both cell types tested proliferated on the construct surface, forming dense cell layers after 2 weeks. However, smooth muscle cells seeded within the construct, assessed with the Alamar blue assay, showed lower proliferation. Cellular distribution within the construct was also evaluated, using confocal microscopy. After 14 days of in vitro culture, 30% of the smooth muscle cells were found on the construct surface compared to 0% at day 1. Our results provide some evidence that cell-seeded plastic compressed collagen has significant potential for bladder tissue regeneration, as these materials allow efficient cell seeding inside the construct as well as cell proliferation.
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Loin d'être « purement allemands », nombre de contes des Grimm réécrivent les contes français largement diffusés en Allemagne au 18e siècle en les « reconfigurant » selon leurs propres paradigmes esthétiques et idéologiques. L'étude introductive de la comparatiste Ute Heidmann montre que ce dialogisme européen est resté peu exploré en raison d'une « scénographie en trompe-l'oeil » qui les présente comme issus du « terroir » hessois. Toutefois, les notes des Grimm (constituées en volume autonome dès 1822), dont une partie importante est traduite et commentée ici pour la première fois en français par Loreto Núñez, indiquent ces intertextes tout en les faisant passer pour des « correspondances » dues à une origine commune. L'étude de Jean Mainil retrace le dialogue intertextuel de Rapunzel (Raiponce) avec Persinette de La Force et Petrosinella de Basile. Les cinq études suivantes de Cyrille François, Nathalie Prince, Pascale Auraix-Jonchière, Jean-Michel Adam et Marcio Venício Barbosa retracent les dialogues intertextuels que les contes des Grimm, eux-mêmes fondamentalement intertextuels, ont sollicité à leur tour dans des textes du 19e et du 20e siècle. Elles montrent comment Hans-Christian Andersen, Jean Lorrain (dont l'étonnant conte Neigefleur est reproduit à la suite de l'étude de Nathalie Prince), Robert Walser, Henry Pourrat et les écrivains brésiliens Millôr Ferandes, Mario Prata, Chico Buarque et Guimarães Rosa inventent de nouvelles formes et des procédés intertextuels originaux en réponse aux contes des Grimm en créant de nouveaux contes originaux comme l'avaient fait les Grimm eux-mêmes en réponse aux narrateurs français. Dans les Mélanges, Veronica Bonanni prolonge ce dossier par une étude consacrée à la traduction par Collodi de L'Oiseau bleue de Marie-Catherine d'Aulnoy, qui procède également d'un véritable dialogue intertextuel.
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BACKGROUND: Specialized pediatric cancer centers (PCCs) are thought to be essential to obtain state-of-the-art care for children and adolescents. We determined the proportion of childhood cancer patients not treated in a PCC, and described their characteristics and place of treatment. PROCEDURE: The Swiss Childhood Cancer Registry (SCCR) registers all children treated in Swiss PCCs. The regional cancer registries (covering 14/26 cantons) register all cancer patients of a region. The children of the SCCR with data from 7 regions (11 cantons) were compared, using specialized software for record linkage. All children <16 years of age at diagnosis with primary malignant tumors, diagnosed between 1990 and 2004, and living in one of these regions were included in the analysis. RESULTS: 22.1% (238/1,077) of patients recorded in regional registries were not registered in the SCCR. Of these, 15.7% (169/1,077) had never been in a PCC while 6.4% (69/1,077) had been in a PCC but were not registered in the SCCR, due to incomplete data flow. In all diagnostic groups and in all age groups, a certain proportion of children was treated outside a PCC, but this proportion was largest in children suffering from malignant bone tumors/soft tissue sarcomas and from malignant epithelial neoplasms, and in older children. The proportion of patients treated in a PCC increased over the study period (P < 0.0001). CONCLUSIONS: One in six childhood cancer patients in Switzerland was not treated in a PCC. Whether these patients have different treatment outcomes remained unclear.
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OBJECTIVE:: The purpose of this study was to assess outcomes and indications in a large cohort of patients who underwent liver transplantation (LT) for liver metastases (LM) from neuroendocrine tumors (NET) over a 27-year period. BACKGROUND:: LT for NET remains controversial due to the absence of clear selection criteria and the scarcity and heterogeneity of reported cases. METHODS:: This retrospective multicentric study included 213 patients who underwent LT for NET performed in 35 centers in 11 European countries between 1982 and 2009. One hundred seven patients underwent transplantation before 2000 and 106 after 2000. Mean age at the time of LT was 46 years. Half of the patients presented hormone secretion and 55% had hepatomegaly. Before LT, 83% of patients had undergone surgical treatment of the primary tumor and/or LM and 76% had received chemotherapy. The median interval between diagnosis of LM and LT was 25 months (range, 1-149 months). In addition to LT, 24 patients underwent major resection procedures and 30 patients underwent minor resection procedures. RESULTS:: Three-month postoperative mortality was 10%. At 5 years after LT, overall survival (OS) was 52% and disease-free survival was 30%. At 5 years from diagnosis of LM, OS was 73%. Multivariate analysis identified 3 predictors of poor outcome, that is, major resection in addition to LT, poor tumor differentiation, and hepatomegaly. Since 2000, 5-year OS has increased to 59% in relation with fewer patients presenting poor prognostic factors. Multivariate analysis of the 106 cases treated since 2000 identified the following predictors of poor outcome: hepatomegaly, age more than 45 years, and any amount of resection concurrent with LT. CONCLUSIONS:: LT is an effective treatment of unresectable LM from NET. Patient selection based on the aforementioned predictors can achieve a 5-year OS between 60% and 80%. However, use of overly restrictive criteria may deny LT to some patients who could benefit. Optimal timing for LT in patients with stable versus progressive disease remains unclear.
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QUESTION UNDER STUDY: To investigate the change over time in the number of ED admissions with positive blood alcohol concentration (BAC) and to evaluate predictors of BAC level. METHODS: We conducted a single site retrospective study at the ED of a tertiary referral hospital (western part of Switzerland) and obtained all the BAC performed from 2002 to 2011. We determined the proportion of ED admissions with positive BAC (number of positive BAC/number of admissions). Regression models assessed trends in the proportion of admissions with positive BAC and the predictors of BAC level among patients with positive BAC. RESULTS: A total of 319,489 admissions were recorded and 20,021 BAC tests were performed, of which 14,359 were positive, divided 34.5% female and 65.5% male. The mean (SD) age was 41.7(16.8), and the mean BAC was 2.12(1.04) permille (g of ethanol/liter of blood). An increase in the number of positive BAC was observed, from 756 in 2002 to 1,819 in 2011. The total number of admissions also increased but less: 1.2 versus 2.4 times more admissions with positive BAC. Being male was independently associated with a higher (+0.19 permille) BAC, as was each passing year (+0.03). A significant quadratic association with age indicated a maximum BAC at age 53. CONCLUSION: We observed an increase in the percentage of admissions with positive BAC that was not limited to younger individuals. Given the potential consequences of alcohol intoxication, and the large burden imposed on ED teams, communities should be encouraged to take measures aimed at reducing alcohol intoxication.