Simultaneous measurement of regional cerebral blood flow by perfusion CT and stable xenon CT: a validation study.

BACKGROUND AND PURPOSE: Knowledge of cerebral blood flow (CBF) alterations in cases of acute stroke could be valuable in the early management of these cases. Among imaging techniques affording evaluation of cerebral perfusion, perfusion CT studies involve sequential acquisition of cerebral CT sections obtained in an axial mode during the IV administration of iodinated contrast material. They are thus very easy to perform in emergency settings. Perfusion CT values of CBF have proved to be accurate in animals, and perfusion CT affords plausible values in humans. The purpose of this study was to validate perfusion CT studies of CBF by comparison with the results provided by stable xenon CT, which have been reported to be accurate, and to evaluate acquisition and processing modalities of CT data, notably the possible deconvolution methods and the selection of the reference artery. METHODS: Twelve stable xenon CT and perfusion CT cerebral examinations were performed within an interval of a few minutes in patients with various cerebrovascular diseases. CBF maps were obtained from perfusion CT data by deconvolution using singular value decomposition and least mean square methods. The CBF were compared with the stable xenon CT results in multiple regions of interest through linear regression analysis and bilateral t tests for matched variables. RESULTS: Linear regression analysis showed good correlation between perfusion CT and stable xenon CT CBF values (singular value decomposition method: R(2) = 0.79, slope = 0.87; least mean square method: R(2) = 0.67, slope = 0.83). Bilateral t tests for matched variables did not identify a significant difference between the two imaging methods (P >.1). Both deconvolution methods were equivalent (P >.1). The choice of the reference artery is a major concern and has a strong influence on the final perfusion CT CBF map. CONCLUSION: Perfusion CT studies of CBF achieved with adequate acquisition parameters and processing lead to accurate and reliable results.

Estratigrafia i evolució conceptual d'un paisatge de muntanya al massís del Garraf: la Maçana-Rovirós-Térmens (Begues)

En aquest estudi, l'aplicació regressiva de tècniques com la prospecció arqueològica, la foto i cartointerpretació, els SIG i el buidatge documental han permès la reconstrucció diacrònica del paisatge de l'àrea de la Maçana-Térmens-Rovirós (Begues). L'estudi paisatgístic del Garraf revesteix un singular interès per la seva condició muntanyenca i la seva intensa antropització. Els entorns de muntanya són medis especialment sensibles a processos de canvi, especialment en el cas del massís del Garraf, proper a importants nuclis d'habitació des de l'antiguitat. El nostre treball mostrarà com, en ocasions, el canvi paisatgístic ha estat irreversible al massís.

World Library and Information Congress: 75th IFLA General Conference and Assembly.

L"edició del 2009 de la trobada de l"IFLA s"ha celebrat a Milà. La maquinària de l"organització va funcionar amb precisió per a aquest esdeveniment. Després d"anys de regularitat en les trobades per tot el món, l"IFLA funciona com un autòmat, una d"aquestes màquines perfectes, tant que podria continuar uncionant en les formes amb exemplar artifici. És un trobada singular, que aplega, a la vegada, la reunió de l"organització, un congrés mundial i una fira comercial; tot això amanit amb una ciutat diferent cada any i un finançament que depèn de la bona marxa de tot l"esdeveniment. En certa mesura, l"IFLA és un aparador de la professió, al qual assisteixen bibliotecaris de tot el món i de centenars d"institucions, amb tot el que suposa d"artificiositat en la representació d"entitats i promoció; un espai de reflexió, amb ponències i debats de molt variat interès que poden trobar-se, generalment, en altres esdeveniments; i una posada a punt dels treballs de tots els comitès, que tenen un complex desenvolupament previ i una àrdua tasca desenvolupada amb generositat per tots els participants.

Evolution and sedimentology of a channel fill in the sandy braided South Saskatchewan River and its comparison to the deposits of an adjacent compound bar

The depositional stratigraphy of within-channel deposits in sandy braided rivers is dominated by a variety of barforms (both singular `unit' bars and complex `compound' bars), as well as the infill of individual channels (herein termed `channel fills'). The deposits of bars and channel fills define the key components of facies models for braided rivers and their within-channel heterogeneity, knowledge of which is important for reservoir characterization. However, few studies have sought to address the question of whether the deposits of bars and channel fills can be readily differentiated from each other. This paper presents the first quantitative study to achieve this aim, using aerial images of an evolving modern sandy braided river and geophysical imaging of its subsurface deposits. Aerial photographs taken between 2000 and 2004 document the abandonment and fill of a 1 3 km long, 80 m wide anabranch channel in the sandy braided South Saskatchewan River, Canada. Upstream river regulation traps the majority of very fine sediment and there is little clay (<1%) in the bed sediments. Channel abandonment was initiated by a series of unit bars that stalled and progressively blocked the anabranch entrance, together with dune deposition and stacking at the anabranch entrance and exit. Complete channel abandonment and subsequent fill of up to 3 m of sediment took approximately two years. Thirteen kilometres of ground-penetrating radar surveys, coupled with 18 cores, were obtained over the channel fill and an adjacent 750 m long, 400 m wide, compound bar, enabling a quantitative analysis of the channel and bar deposits. Results show that, in terms of grain-size trends, facies proportions and scale of deposits, there are only subtle differences between the channel fill and bar deposits which, therefore, renders them indistinguishable. Thus, it may be inappropriate to assign different geometric and sedimentological attributes to channel fill and bar facies in object-based models of sandy braided river alluvial architecture.

Boris Vian dans ses poèmes

El artículo se propone mostrar cómo el estudio de los poemas y canciones de Boris Vian sólo cobra sentido mediante un análisis de conjunto. Tras la aparente dispersión de temas y estilos, bajo la apariencia superficial, cómica y en ocasiones incluso grotesca y banal de sus poemas y canciones, se oculta una unidad y una coherencia profundas y minuciosamente calculadas. Para expresarla Vian huye de las limitaciones de la lógica heredada de Aristóteles y opta por utilizar la técnica del collage, yuxtaponiendo una pluralidad de situaciones y acciones en las que lo real se entremezcla con lo imaginario, cuyo resultado final es la representación de una realidad única, indivisible y a la vez relativa y singular en función de cada individuo, en la que los aparentes antagonismos se revelan como elementos complementarios en el proceso de individualización y conocimiento del «yo» interior.

Sarraïns sota el domini de la família Montcada: les aljames de la baronia d'Aitona al segle XV

L'any 1212 la família Montcada es fa amb el control de l´àrea del Baix Segre, una de les mes densament habitades en època islàmica. Dos segles després, tot i la profunda implantació del sistema feudal, la comunitat musulmana no només hi conserva una forta presencia poblacional sinó que a més mante vives bona part de les seves institucions. Aquesta comunitat -organitzada en aljames- es concentra en les viles d’Aitona, Seròs i Mequinensa, on constitueix el gruix de la població. Aquesta tensió entre els antics i els nous marcs de relacions en que es mou la comunitat islàmica (materialitzats en sistemes de tinença com l’emfiteusi) conferí a la zona un caire marcadament singular.

Tradición y modernidad en las políticas educativas en España: una revisión de las últimas décadas

En el presente artículo trazamos un panorama aproximativo de algunas de las cuestiones más relevantes que determinan, al tiempo que reflejan, las políticas educativas en España desde la década de 1980 hasta la actualidad. Esta revisión de los últimos 25 años permitirá apreciar, siquiera de manera epidérmica e inevitablemente parcial, la tensión o dialéctica entre la tradición-caracterizada por la persistencia de formas caducas en la concepción y en la provisión educativa- y la modernidad-portadora de la tendencia al cambio y a la innovación, si bien no exenta de ambigüedad y contradicción en su propio desarrollo-. Nos detenemos en aquellos ejes a partir de los cuales se articula nuestra reflexión, tales como las políticas educativas, la organización del sistema educativo, la convergencia europea, las organizaciones transnacionales reguladoras de las políticas educativas y prospectivas, finalizando con algunas conclusiones que, aun siendo abiertas, plantean la persistencia de las dinámicas reproductoras. Nuestro análisis se ciñe, para esta ocasión, al ámbito de la educación formal, sin dejar de reconocer la importancia creciente de los espacios de educación no formal e informal, y de los sectores emergentes derivados de los mismos. Como se verá, nuestro planteamiento se enmarca dentro de una interpretación singular acerca de las derivaciones y consecuencias de la modernidad tardía en la que se inscribe nuestro período de estudio

Wavelet Analysis in Turbulence

The objective of this thesis is to study wavelets and their role in turbulence applications. Under scrutiny in the thesis is the intermittency in turbulence models. Wavelets are used as a mathematical tool to study the intermittent activities that turbulence models produce. The first section generally introduces wavelets and wavelet transforms as a mathematical tool. Moreover, the basic properties of turbulence are discussed and classical methods for modeling turbulent flows are explained. Wavelets are implemented to model the turbulence as well as to analyze turbulent signals. The model studied here is the GOY (Gledzer 1973, Ohkitani & Yamada 1989) shell model of turbulence, which is a popular model for explaining intermittency based on the cascade of kinetic energy. The goal is to introduce better quantification method for intermittency obtained in a shell model. Wavelets are localized in both space (time) and scale, therefore, they are suitable candidates for the study of singular bursts, that interrupt the calm periods of an energy flow through various scales. The study concerns two questions, namely the frequency of the occurrence as well as the intensity of the singular bursts at various Reynolds numbers. The results gave an insight that singularities become more local as Reynolds number increases. The singularities become more local also when the shell number is increased at certain Reynolds number. The study revealed that the singular bursts are more frequent at Re ~ 107 than other cases with lower Re. The intermittency of bursts for the cases with Re ~ 106 and Re ~ 105 was similar, but for the case with Re ~ 104 bursts occured after long waiting time in a different fashion so that it could not be scaled with higher Re.

The Outcry of the Periphery? An Analysis of Ticino's No to Immigration

When the popular initiative "against mass immigration" was accepted by the Swiss people and cantons on 9 February 2014, Ticino had by far the highest approval rate. The Italian-speaking canton thus once more confirmed its singular position, assumed since the 1990s, on popular votes regarding immigration and foreign policy. This seems to be indicative of wider crises and changes in both the economic and political spheres that have favoured the emergence of a political opposition between centre and periphery. The results of a survey among 1400 citizens of Ticino after the vote of 9 February confirm this. In essence, on top of the question of immigration, the vote was influenced by a fearful perception of Ticino as a "double periphery" vis-à-vis both Berne and Lombardy.

Hiilidioksidin päästökaupan markkinatilanne vuoden 2005 alussa

Diplomityössä selvitettiin EU:ssa vuoden 2005 alusta alkavan päästökauppajärjestelmän toimintaympäristöä, sen taustaa ja sopimuksia joihin se pohjautuu. Varsinaisena tutkimusongelmana pyrittiin tunnistamaan muuttujat, jotka päästökaupan osalta vaikuttavat päästökaupan piirissä toimivaan yritykseen ja verrattiin eri toimijoita näiden tekijöiden avulla. Tekijöitä tarkasteltiin eri tasoilla niin, että ylimpänä tasona toimi koko maailman taso ja alimpana yksittäinen toimija. Näiden välissä tarkastelutasoina olivat EU:n laajuinen taso, yksittäisen maan laajuinen taso, sekä toimijaryhmän muodostaman toimialasektorin taso. Esimerkkinä näiden tekijöiden käytöstä toimijoiden vertailussa otettiin tarkasteltavaksi kolme suomalaista hiilivoimalaa: Lahtienergian omistama Kymijärven hiilivoimalaitos, Fortumin ja Teollisuuden voiman yhdessä omistama Meri-Porin hiilivoimalaitos sekä Helsingin Energian omistama Salmisaaren voimalaitos. Vertailu osoitti, että suurin laitoksista, eli Meri-Porin voimalaitos on suurimpien haasteiden edessä päästökaupan alkaessa, mutta toisaalta sillä on myös suurimmat resurssit selviytyä niistä.

The differentiable chain functor is not homotopy equivalent to the continuous chain functor

Let $S_*$ and $S_*^\{infty}$ be the functors of continuous and differentiable singular chains on the category of differentiable manifolds. We prove that the natural transformation $i: S_*^\infty \rightarrow S_*$, which induces homology equivalences over each manifold, is not a natural homotopy equivalence.

Aurora Bertrana : Bringing "otherness" home

“Decidida a viure al preu que sigui” underscores contemporary writer Maria-Antònia Oliver in her prologue to Aurora Bertrana’s fourth book, El Marroc sensual i fanàtic (1936). The urge to travel, to explore the world and to slake her thirst for new experiences shaped much of the personality and the work of this Girona-born writer. Taking her own travels as a starting point, Bertrana distinguished herself in the genre of travel writing on exotic countries, which at that time underwent a significant revival in Catalonia. Bertrana’s originality lies partly in the image of the woman traveller that she consciously cultivated for herself, and partly in the way she narrates her travels. This article seeks to recover this author and make visible her singular way of presenting otherness.

Cuestiones clave de la Lingüística

Juan Carlos Moreno Cabrera, catedrático de lingüística en la Universidad Autónoma de Madrid, acaba de publicar el libro Cuestiones clave de la Lingüística . Este título se suma a una extensa producción, en la que Moreno Cabrera se ocupa de teoría sintáctica ( Fundamentos de Sintaxis General , 1987),tipología lingüística (El Universo de las lenguas, 2003), ensayo (El nacionalismolingüístico, 2008) y manuales (Curso Universitario de Ling üística general, 1991-2000), entre otros campos de estudio y facetas de la edición. El prestigio de Juan Carlos Moreno Cabrera está basado en una formación rigurosa y singular, en un espíritu de investigación crítico y en un estilo sugestivo y elocuentwe.

Monoidal functors, acyclic models and chain operads

We prove that for a topological operad $P$ the operad of oriented cubical singular chains, $C^{\ord}_\ast(P)$, and the operad of simplicial singular chains, $S_\ast(P)$, are weakly equivalent. As a consequence, $C^{\ord}_\ast(P\nsemi\mathbb{Q})$ is formal if and only if $S_\ast(P\nsemi\mathbb{Q})$ is formal, thus linking together some formality results which are spread out in the literature. The proof is based on an acyclic models theorem for monoidal functors. We give different variants of the acyclic models theorem and apply the contravariant case to study the cohomology theories for simplicial sets defined by $R$-simplicial differential graded algebras.

Interventions présumées des scribes concernant le motif de l'arbre sacré dans le Pentateuque

Abstract: This article deals with several presumed scribal interventions which all concern the sacred tree motif. One finds deliberate changes in the MT, in the Septuagint, in Targum Onkelos and in the Vulgate. The Greek translators of Genesis and Samuel (1-2 Kingdoms) avoided rendering the word אשׁל "tamarisk" by its equivalent μυρίκη, chosing instead the word ἄρουρα "field". Similarly, the Greek translator of Genesis, in the passage of the death of Rebecca's nurse Deborah, passed over the motif of her burial under a grand tree. According to the hypothesis of the present article, all four changes are related to one other; they might be due to the translator's fear to connect the respective texts with traditions and customs concerning the Egyptian god Osiris. On the other side, a scribe of the proto-Massoretic tradition modified the readings mentioning the large tree of Mamre close to Hebron. By changing the noun's number from singular to plural the corrector tried to conceal the existence and importance of the sacred tree in the tradition of Abraham. By contrast, the scribe did not modify texts related to the sacred tree of Shechem. This disparity of treatment may be explained by the fact that, in the view of the Judean scribe, the tree of Shechem would put the Samaritans in a bad light. Finally, the authors of Targum Onkelos and of the Vulgate intervened almost systematically in Pentateuchal texts having the terms אֵלוֹן) אלון or אַלּוֹן ), which always designate a holy tree. The two expressions are rendered by terms referring to plains (Targum Onkelos) or a valley (Vulgate).