948 resultados para Almost always algebra


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Esophageal intramural pseudodiverticulosis is a rare pathology whose etiology is unknown, but which is frequently associated with three highly prevalent entities: esophageal reflux disease, esophageal candidosis and alcoholic esophagitis. With conservative treatment the course of these pathologies is usually benign. However, some severe cases are resistant to conservative treatment and may require more aggressive management. We here present the case of patient suffering from a severe esophagitis complicated by chronic mediastinitis with life-threatening repercussions, requiring esophagectomy as treatment.

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We analyze the effects of a domestic standard that reduces an externality associated with the consumption of the good targeted by the standard, using a model in which foreign and domestic producers compete in the domestic good market. Producers can reduce expected damage associated with the externality by incurring a cost that varies by source of origin. Despite potential protectionism, the standard is useful in correcting the consumption externality in the domestic country. Protectionism occurs when the welfare-maximizing domestic standard is higher than the international standard maximizing welfare inclusive of foreign profits. The standard is actually anti-protectionist when foreign producers are much more efficient at addressing the externality than are domestic producers. Possible exclusion of domestic or foreign producers arises with large standards, which may alter the classification of a standard as protectionist or non-protectionist. The paper provides important implications for the estimation and use of tariff equivalents of nontariff barriers.

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The African Republic of Cape Verde consists of nine inhabited and several uninhabited volcanic islands set out in the Atlantic Ocean, about 500 km off the most westerly point of the African mainland and 1500 km south of the Canary Islands @g. 2). Most are rugged and mountainous; three (Sal, Maio, and Boavista) are flat, desert islands with sand beaches. Precipitation is meagre and very erratic; indeed Cape Verde can be seen as an island extension of the arid Sahel zone. Three species of the genus Phoenix are recorded from the Cape Verde Islands, P. akzctyli&a L., P. canariensis Chabaud and P. atlantica A. Chev. While the former two species have almost certainly been introduced by man, the latter is said to be endemic to the islands. Perhaps because the Cape Verdes are a particularly isolated set of islands or because palms are notoriously awkward to collect, little is known about the taxonomy, origins and natural history of this species. Phoenix atlantica was described by the French botanist Auguste Chevalier (1935a) following field exploration in the Cape Verdes in 1934 (Chevalier 1934: 1153). Chevalier provided limited diagnostic characters, defining the species as a clustering palm with 2-6 trunks, 5-15 m in height with dark green leaves 2-3 m in length. He considered it to be most similar in form to P. &ctyZzjkra and P. canariensis, possessing characters of both (Chevalier 1935a). Chevalier’s description indicates that Phoenix atlantica can be distinguished easily from P. canariensis by its clustering growth form (P. canariensis always has a single, stout trunk) and its shorter, straighter leaves. However, the differences between P. atlantica and P. dactylzjkra appear much more subtle. For example, while P. dacfylifera is usually observed as single-stemmed, when left undisturbed for a number of years it becomes clustering like the Cape Verde Phoenix, so this character on its own is unreliable. Further alleged distinctions include acuminate (P. atlantica) versus rounded (P. dactylzjkra) petals in the male flowers (Chevalier 1935a, b, Greuter 1967: 249, and Brochmann et al. 1997), fruit 2 cm long (P. atlantica) versus fruit more than 2.5 cm long (P. dactyl&a) (Brochmann et al.

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OBJECTIVES: Jean Cruveilhier has always been described as a pioneer in pathological anatomy. Almost nothing has been reported concerning his exceptional methodology allying pre-mortem clinical description and syndromic classification of neurological and neurosurgical diseases, and post-mortem meticulous dissections. Cruveilhier's methodology announced the birth of the anatomoclinical method built up by Jean-Martin Charcot and the neurological French school during the 19th century. The aim of our work is to extract the quintessence of Cruveilhier's contributions to skull base pathology through his cogent clinical descriptions coupled with exceptional lithographs of anterior skull base, suprasellar and cerebello-pontine angle tumors. METHODS: We reviewed the masterwork of Jean Cruveilhier on pathological anatomy and we selected the chapters dedicated to central nervous system pathologies, mainly skull base diseases. A systematic review was performed on Pubmed/Medline and Google Scholar using the keywords "Jean Cruveilhier", "Skull base pathology", "Anatomoclinical method". RESULTS: Among his descriptions, Cruveilhier dedicated large chapters to neurosurgical diseases including brain tumors, cerebrovascular pathologies, malformations of the central nervous system, hydrocephalus, brain infections and spinal cord compressions. CONCLUSION: This work emphasizes on the role of Jean Cruveilhier in the birth of the anatomoclinical method particularly in neuroscience during a 19th century rich of epistemological evolutions toward an evidence-based medicine, through the prism of Cruveilhier's contribution to skull base pathology.

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The subject "Value and prices in Russian economic thought (1890--1920)" should evoke several names and debates in the reader's mind. For a long time, Western scholars have been aware that the Russian economists Tugan-Baranovsky and Bortkiewicz were active participants to the Marxian transformation problem, that the mathematical models of Dmitriev prefigured forthcoming neoricardian based models, and that many Russian economists were either supporting the Marxian labour theory of value or being revisionists. Moreover, these ideas were preparing the ground for Soviet planning. Russian scholars additionally knew that this period was the time of introduction of marginalism in Russia, and that, during this period, economists were active in thinking the relation of ethics with economic theory. All these issues are well covered in the existing literature. But there is a big gap that this dissertation intends to fill. The existing literature handles these pieces separately, although they are part of a single, more general, history. All these issues (the labour theory of value, marginalism, the Marxian transformation problem, planning, ethics, mathematical economics) were part of what this dissertation calls here "The Russian synthesis". The Russian synthesis (in the singular) designates here all the attempts at synthesis between classical political economy and marginalism, between labour theory of value and marginal utility, and between value and prices that occurred in Russian economic thought between 1890 and 1920, and that embraces the whole set of issues evoked above. This dissertation has the ambition of being the first comprehensive history of that Russian synthesis. In this, this contribution is unique. It has always surprised the author of the present dissertation that such a book has not yet been written. Several good reasons, both in terms of scarce availability of sources and of ideological restrictions, may accounted for a reasonable delay of several decades. But it is now urgent to remedy the situation before the protagonists of the Russian synthesis are definitely classified under the wrong labels in the pantheon of economic thought. To accomplish this task, it has seldom be sufficient to gather together the various existing studies on aspects of this story. It as been necessary to return to the primary sources in the Russian language. The most important part of the primary literature has never been translated, and in the last years only some of them have been republished in Russian. Therefore, most translations from the Russian have been made by the author of the present dissertation. The secondary literature has been surveyed in the languages that are familiar (Russian, English and French) or almost familiar (German) to the present author, and which are hopefully the most pertinent to the present investigation. Besides, and in order to increase the acquaintance with the text, which was the objective of all this, some archival sources were used. The analysis consists of careful chronological studies of the authors' writings and their evolution in their historical and intellectual context. As a consequence, the dissertation brings new authors to the foreground - Shaposhnikov and Yurovsky - who were traditionally confined to the substitutes' bench, because they only superficially touched the domains quoted above. In the Russian synthesis however, they played an important part of the story. As a side effect, some authors that used to play in the foreground - Dmitriev and Bortkiewicz - are relegated to the background, but are not forgotten. Besides, the dissertation refreshes the views on authors already known, such as Ziber and, especially, Tugan-Baranovsky. The ultimate objective of this dissertation is to change the opinion that one could have on "value and prices in Russian economic thought", by setting the Russian synthesis at the centre of the debates.

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Let a class $\F$ of densities be given. We draw an i.i.d.\ sample from a density $f$ which may or may not be in $\F$. After every $n$, one must make a guess whether $f \in \F$ or not. A class is almost surely testable if there exists such a testing sequence such that for any $f$, we make finitely many errors almost surely. In this paper, several results are given that allowone to decide whether a class is almost surely testable. For example, continuity and square integrability are not testable, but unimodality, log-concavity, and boundedness by a given constant are.

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RAPPORT DE SYNTHESE : Introduction : les patients obèses morbides présentent un risque majeur de développer des calculs biliaires en raison d'une sécrétion accrue de cholestérol dans la bile. Ce risque, davantage élevé dans la phase de perte pondérale rapide consécutive à la chirurgie bariatrique ou lors de régimes amaigrissants, est souvent la cause de nombreux symptômes, voire de complications biliaires. Aussi l'association d'une cholécystectomie à la chirurgie bariatrique, notamment le bypass gastrique laparoscopique a-t-elle été proposée afin d'éviter ces complications parfois redoutables dans cette population fragile. Ce concept a cependant fait l'objet de démentis dans de récentes études où ce risque apparaîtrait moins élevé, et la cholécystectomie durant le by- pris gastrique laparoscopique pourrait être grevée de difficultés et présenter des risques opératoires non négligeables pour le patient. Patients et méthodes : notre série comporte 772 patients opérés entre 2000 et 2007 par by-pass gastrique laparoscopique, avec montage d'une anse en Y selon Roux. Ces patients obèses morbides avaient été sélectionnés sur la base d'une anamnèse concluante, d'un examen anthropométrique, d'un bilan sanguin et d'un ultrason abdominal. Une analyse rétrospective des résultats d'ultrason abdominal préopératoire et des rapports histopathologiques des vésicules biliaires en postopératoire a été réalisée chez les patients opérés avant 2004. Résultats : 58 patients (7,5 %) avaient déjà eu une cholécystectomie. L'US abdominal a révélé des calculs ou de la boue biliaire chez 81 patients (11,3 %), un polype chez un patient et une vésicule biliaire normale chez les patients restants. La cholécystectomie a été réalisée concomitamment au by-pass gastrique chez 66S patients (91,7 %) et des calculs biliaires retrouvés à l'examen per-opératoire des vésicules biliaires chez 25 patients (3,9 %), rapportant alors la prévalence de la cholélithiase à 21,2 % dans cette population. L'âge des patients porteurs de calculs biliaires était significativement plus élevé que celui des patients sans calculs biliares (43,5 contre 38,7 ans, P < 0,0001). A l'examen histopathologique, des anomalies ont été décrites dans 81,8 % des vésicules biliaires, consistant pour la plupart en cholécystite chronique et cholestérolose. Aucune complication post-opératoire n'a été associée à la cholécystectomie et le prolongement du temps opératoire était en moyenne de 19 minutes (4 - 45 minutes) sans aucun impact sur le séjour hospitalier. La cholécystectomie n'a pas été réalisée chez 59 patients (8,3 %) en raison de conditions opératoires défavorables, notamment une exposition insuffisante. Un traitement d'acide ursodésoxycholique a été prescrit sur une période de 6 mois et aucun de ces patients n'a manifesté de symptômes biliaires. Conclusion : la cholécystectomie peut être réalisée à titre prophylactique et en toute sécurité au cours du by-pass gastrique laparoscopique. Cet acte opératoire supplémentaire sans conséquence sur le séjour hospitalier, constitue selon la présente étude une forme de prophylaxie recommandable dans la prévention de la formation des calculs biliaires dans la phase de perte pondérale post-opératoire. Sa supériorité ou non par rapport à la prophylaxie médicamenteuse à l'acide ursodésoxycholique n'a pas encore été établie. Des études prospectives randomisées seraient nécessaires afin de confirmer l'avantage de l'une ou l'autre de ces deux alternatives.

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Visual analysis of electroencephalography (EEG) background and reactivity during therapeutic hypothermia provides important outcome information, but is time-consuming and not always consistent between reviewers. Automated EEG analysis may help quantify the brain damage. Forty-six comatose patients in therapeutic hypothermia, after cardiac arrest, were included in the study. EEG background was quantified with burst-suppression ratio (BSR) and approximate entropy, both used to monitor anesthesia. Reactivity was detected through change in the power spectrum of signal before and after stimulation. Automatic results obtained almost perfect agreement (discontinuity) to substantial agreement (background reactivity) with a visual score from EEG-certified neurologists. Burst-suppression ratio was more suited to distinguish continuous EEG background from burst-suppression than approximate entropy in this specific population. Automatic EEG background and reactivity measures were significantly related to good and poor outcome. We conclude that quantitative EEG measurements can provide promising information regarding current state of the patient and clinical outcome, but further work is needed before routine application in a clinical setting.

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Let I be an ideal in a local Cohen-Macaulay ring (A, m). Assume I to be generically a complete intersection of positive height. We compute the depth of the Rees algebra and the form ring of I when the analytic deviation of I equals one and its reduction number is also at most one. The formu- las we obtain coincide with the already known formulas for almost complete intersection ideals.

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We consider the Clifford algebra C(q) of a regular quadratic space (V, q) over a field K with its structure of Z/2Z-graded K-algebra. We give a characterization of the group of graded automorphisms of C(q). In the last section we introduce the Z/nZ-graded algebras and we study as well as the group of graded automorphisms for some of them.

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Quaternary prevention aims to protect the patient or population against overmedicalisation. Quaternary prevention influences all the activities of family medicine by questioning the utility of primary prevention and early diagnosis, identifying the risks of creating new pathological entities and practicing a maximalist medicine. Family doctors can support quaternary prevention by focusing on their patients' priorities and the local resources of an efficient health system.

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The evolution of continuous traits is the central component of comparative analyses in phylogenetics, and the comparison of alternative models of trait evolution has greatly improved our understanding of the mechanisms driving phenotypic differentiation. Several factors influence the comparison of models, and we explore the effects of random errors in trait measurement on the accuracy of model selection. We simulate trait data under a Brownian motion model (BM) and introduce different magnitudes of random measurement error. We then evaluate the resulting statistical support for this model against two alternative models: Ornstein-Uhlenbeck (OU) and accelerating/decelerating rates (ACDC). Our analyses show that even small measurement errors (10%) consistently bias model selection towards erroneous rejection of BM in favour of more parameter-rich models (most frequently the OU model). Fortunately, methods that explicitly incorporate measurement errors in phylogenetic analyses considerably improve the accuracy of model selection. Our results call for caution in interpreting the results of model selection in comparative analyses, especially when complex models garner only modest additional support. Importantly, as measurement errors occur in most trait data sets, we suggest that estimation of measurement errors should always be performed during comparative analysis to reduce chances of misidentification of evolutionary processes.

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Purpose. To evaluate the impact of mobile devices and apps on the daily clinical activity of young radiation oncologists. Methods. A web-based questionnaire was sent to 382 young (≤40 years) members of the Italian Association of Radiation Oncology (AIRO). The 14 items investigated the diffusion of mobile devices (smartphones and/or tablets), their impact on daily clinical activity, and possible differences perceived by the participants over time. Results. A total of 158 questionnaires were available for statistical evaluation (response rate 41%). Up to 75% of respondents declared they used an electronic device during their clinical activity. Conversely, 82% considered the impact of smartphones/tables on daily practice low to moderate. Daily device use increased significantly from 2009 to 2012, with high daily use rates rising from 5% to 39.9%. Fulfillment of professional needs was declared by less than 42% of respondents and compliance with app indications by 32%. Almost all physicians desired in 2012 a comprehensive website concerning a variety of apps covering radiation oncologists' needs. Conclusions. Mobile devices are widely used by young Italian radiation oncologists in their daily clinical practice, while the indications so obtained are not always followed. Nevertheless, it would be important to verify the consistency of information found within apps, in order to avoid potential errors that might be detrimental to patients.