La fluidité des espaces communicationnels : partager des vidéos en ligne dans la vie quotidienne

Internet évolue avec la société et les nouvelles technologies, mais ses usages restent centrés sur le principe communicationnel de partager ses idées, ses histoires avec d’autres personnes. Comprendre les modes de communication des internautes offre des défis de taille aux chercheurs. Malgré une riche littérature sur les usages d’Internet, peu d’études se sont penchées sur l’analyse en profondeur des habitudes des internautes ordinaires. Cette thèse a pour objet d’étude le partage de contenus en ligne, car il s’agit d’une pratique permettant de réfléchir sur le rapport des usagers à la technologie. En m’inspirant des travaux d’Henri Lefebvre et de Michel de Certeau, je mobilise le concept de la vie quotidienne, concept qui met en lumière les processus à travers laquelle les gens font sens de leur vie. Afin de mieux saisir le quotidien, lequel est mobile, fluide et multiple, des métaphores spatiales tirées d’études des sciences, technologies et société (STS) seront mobilisées. Les concepts d’espace fluide et de feu sont idéaux pour étudier les pratiques de partage de vidéo que l’on peut qualifier de mutables et adaptables. Dans cette thèse, l’accent est mis sur les expériences subjectives des internautes ; ainsi, j’ai adopté une méthodologie qualitative pour recueillir les témoignages d’une dizaine de participants décrivant longuement leurs pratiques. En effet, j’ai rencontré chaque personne à plusieurs reprises et nous avons discuté d’exemples spécifiques. À travers les thèmes récurrents qui ont émergé des verbatims, et dans la tradition de la théorisation ancrée, la première partie de l’analyse fournit une riche description du quotidien des participants. J’explore en particulier la façon dont les internautes adaptent leur partage sur leurs expériences des sites de réseaux sociaux, comment la vidéo est utilisée dans le maintien de leurs relations sociales, et comment le partage des vidéos complémente leurs conversations. Sachant que les pratiques en ligne et hors ligne se fondent l’une dans l’autre, la deuxième partie de l’analyse articule la complexité de la vie quotidienne et la fluidité des pratiques de partage à l’aide du concept de l’objet fluide pour traiter des aspects complexes, dynamiques et souples des pratiques des internautes ordinaires. Cette recherche qualitative fournit un portrait de l’expérience humaine qui est autant détaillé que possible. Elle permet de souligner que c’est dans une variété contextes non remarquables – car faisant partie intégrante de la vie quotidienne – que les Internautes naviguent et que les activités humaines sont sans cesse construites et transformées, ouvrant des possibilités vers de nouvelles façons de faire et de penser. La thèse poursuit un dialogue interdisciplinaire entre la communication (les Internet Studies notamment) et les études des sciences, technologies et société (STS), tout en apportant de nombreuses données empiriques sur les pratiques des internautes « ordinaires ». De plus, la thèse offre des métaphores capables d’ouvrir de nouvelles perspectives pour l’analyse des usages du Web social. Elle apporte également une contribution originale en intégrant des approches théoriques des pratiques quotidiennes avec la théorisation ancrée. Tant les fondements conceptuels et des approches méthodologiques développées ici seront des exemples très utiles pour d’autres chercheurs intéressés à poursuivre la compréhension des pratiques quotidiennes impliquant l’Internet, surtout quand ces derniers impliquent le visuel, l’émotif et le relationnel.

Factors affecting postoperative cerebrospinal fluid leaks after retrosigmoidal craniotomy for vestibular schwannomas

OBJECT: The aim of this study was to identify patients likely to develop CSF leaks after vestibular schwannoma surgery using a retrospective analysis for the identification of risk factors. METHODS: Between January 2001 and December 2006, 420 patients underwent retrosigmoidal microsurgical tumor removal in a standardized procedure. Of these 420 patients, 363 underwent treatment for the first time, and 27 suffered from recurrent tumors. Twenty-six patients had bilateral tumors due to neurofibromatosis Type 2, and 4 patients had previously undergone radiosurgical treatment. An analysis was performed to examine the incidence of postoperative CSF fistulas in all 4 groups. RESULTS: The incidence of CSF leakage was higher in the tumor recurrence group (11.1%) than in patients undergoing surgery for the first time (4.4%). There were no CSF fistulas in the neurofibromatosis Type 2 group or in patients with preoperative radiosurgical treatment. Tumor size was identified as a possible risk factor in a previous study. CONCLUSIONS: Surgery for recurrent tumors is a significant risk factor for the development of CSF leaks.

Spinal cerebrospinal fluid leak as the cause of chronic subdural hematomas in nongeriatric patients

OBJECT The etiology of chronic subdural hematoma (CSDH) in nongeriatric patients (≤ 60 years old) often remains unclear. The primary objective of this study was to identify spinal CSF leaks in young patients, after formulating the hypothesis that spinal CSF leaks are causally related to CSDH. METHODS All consecutive patients 60 years of age or younger who underwent operations for CSDH between September 2009 and April 2011 at Bern University Hospital were included in this prospective cohort study. The patient workup included an extended search for a spinal CSF leak using a systematic algorithm: MRI of the spinal axis with or without intrathecal contrast application, myelography/fluoroscopy, and postmyelography CT. Spinal pathologies were classified according to direct proof of CSF outflow from the intrathecal to the extrathecal space, presence of extrathecal fluid accumulation, presence of spinal meningeal cysts, or no pathological findings. The primary outcome was proof of a CSF leak. RESULTS Twenty-seven patients, with a mean age of 49.6 ± 9.2 years, underwent operations for CSDH. Hematomas were unilateral in 20 patients and bilateral in 7 patients. In 7 (25.9%) of 27 patients, spinal CSF leakage was proven, in 9 patients (33.3%) spinal meningeal cysts in the cervicothoracic region were found, and 3 patients (11.1%) had spinal cysts in the sacral region. The remaining 8 patients (29.6%) showed no pathological findings. CONCLUSIONS The direct proof of spinal CSF leakage in 25.9% of patients suggests that spinal CSF leaks may be a frequent cause of nongeriatric CSDH.

Defining the Fluid framework

In this position paper we present the developing Fluid framework, which we believe offers considerable advantages in maintaining software stability in dynamic or evolving application settings. The Fluid framework facilitates the development of component software via the selection, composition and configuration of components. Fluid's composition language incorporates a high-level type system supporting object-oriented principles such as type description, type inheritance, and type instantiation. Object-oriented relationships are represented via the dynamic composition of component instances. This representation allows the software structure, as specified by type and instance descriptions, to change dynamically at runtime as existing types are modified and new types and instances are introduced. We therefore move from static software structure descriptions to more dynamic representations, while maintaining the expressiveness of object-oriented semantics. We show how the Fluid framework relates to existing, largely component based, software frameworks and conclude with suggestions for future enhancements. © 2007 IEEE.

Data driven graphical applications:a fluid approach

The inclusion of high-level scripting functionality in state-of-the-art rendering APIs indicates a movement toward data-driven methodologies for structuring next generation rendering pipelines. A similar theme can be seen in the use of composition languages to deploy component software using selection and configuration of collaborating component implementations. In this paper we introduce the Fluid framework, which places particular emphasis on the use of high-level data manipulations in order to develop component based software that is flexible, extensible, and expressive. We introduce a data-driven, object oriented programming methodology to component based software development, and demonstrate how a rendering system with a similar focus on abstract manipulations can be incorporated, in order to develop a visualization application for geospatial data. In particular we describe a novel SAS script integration layer that provides access to vertex and fragment programs, producing a very controllable, responsive rendering system. The proposed system is very similar to developments speculatively planned for DirectX 10, but uses open standards and has cross platform applicability. © The Eurographics Association 2007.

Human Herpesvirus Infections Of The Central Nervous System: Laboratory Diagnosis Based On Dna Detection By Nested Pcr In Plasma And Cerebrospinal Fluid Samples.

Infections of the central nervous systems (CNS) present a diagnostic problem for which an accurate laboratory diagnosis is essential. Invasive practices, such as cerebral biopsy, have been replaced by obtaining a polymerase chain reaction (PCR) diagnosis using cerebral spinal fluid (CSF) as a reference method. Tests on DNA extracted from plasma are noninvasive, thus avoiding all of the collateral effects and patient risks associated with CSF collection. This study aimed to determine whether plasma can replace CSF in nested PCR analysis for the detection of CNS human herpesvirus (HHV) diseases by analysing the proportion of patients whose CSF nested PCR results were positive for CNS HHV who also had the same organism identified by plasma nested PCR. In this study, CSF DNA was used as the gold standard, and nested PCR was performed on both types of samples. Fifty-two patients with symptoms of nervous system infection were submitted to CSF and blood collection. For the eight HHV, one positive DNA result-in plasma and/or CSF nested PCR-was considered an active HHV infection, whereas the occurrence of two or more HHVs in the same sample was considered a coinfection. HHV infections were positively detected in 27/52 (51.9%) of the CSF and in 32/52 (61.5%) of the plasma, difference not significant, thus nested PCR can be performed on plasma instead of CSF. In conclusion, this findings suggest that plasma as a useful material for the diagnosis of cases where there is any difficulty to perform a CSF puncture.

Metamorfose planar via métodos Level Set e Particle Level Set para a reconstrução de superfícies tridimensionais

Evolving interfaces were initially focused on solutions to scientific problems in Fluid Dynamics. With the advent of the more robust modeling provided by Level Set method, their original boundaries of applicability were extended. Specifically to the Geometric Modeling area, works published until then, relating Level Set to tridimensional surface reconstruction, centered themselves on reconstruction from a data cloud dispersed in space; the approach based on parallel planar slices transversal to the object to be reconstructed is still incipient. Based on this fact, the present work proposes to analyse the feasibility of Level Set to tridimensional reconstruction, offering a methodology that simultaneously integrates the proved efficient ideas already published about such approximation and the proposals to process the inherent limitations of the method not satisfactorily treated yet, in particular the excessive smoothing of fine characteristics of contours evolving under Level Set. In relation to this, the application of the variant Particle Level Set is suggested as a solution, for its intrinsic proved capability to preserve mass of dynamic fronts. At the end, synthetic and real data sets are used to evaluate the presented tridimensional surface reconstruction methodology qualitatively.

Metamorfose planar via métodos Level Set e Particle Level Set para a reconstrução de superfícies tridimensionais

Evolving interfaces were initially focused on solutions to scientific problems in Fluid Dynamics. With the advent of the more robust modeling provided by Level Set method, their original boundaries of applicability were extended. Specifically to the Geometric Modeling area, works published until then, relating Level Set to tridimensional surface reconstruction, centered themselves on reconstruction from a data cloud dispersed in space; the approach based on parallel planar slices transversal to the object to be reconstructed is still incipient. Based on this fact, the present work proposes to analyse the feasibility of Level Set to tridimensional reconstruction, offering a methodology that simultaneously integrates the proved efficient ideas already published about such approximation and the proposals to process the inherent limitations of the method not satisfactorily treated yet, in particular the excessive smoothing of fine characteristics of contours evolving under Level Set. In relation to this, the application of the variant Particle Level Set is suggested as a solution, for its intrinsic proved capability to preserve mass of dynamic fronts. At the end, synthetic and real data sets are used to evaluate the presented tridimensional surface reconstruction methodology qualitatively.

Central nitrergic system regulation of neuroendocrine secretion, fluid intake and blood pressure induced by angiotensin-II

Background: Nitric oxide (NO) synthesis has been described in several circumventricular and hypothalamic structures in the central nervous system that are implicated in mediating central angiotensin-II (ANG-II) actions during water deprivation and hypovolemia. Neuroendocrine and cardiovascular responses, drinking behavior, and urinary excretions were examined following central angiotensinergic stimulation in awake freely-moving rats pretreated with intracerebroventricular injections of N omega-nitro-L-arginine methyl ester (L-NAME, 40 mu g), an inhibitor of NO synthase, and L-arginine (20 ug), a precursor of NO. Results: Injections of L-NAME or ANG-II produced an increase in plasma vasopressin (VP), oxytocin (OT) and atrial natriuretic peptide (ANP) levels, an increase in water and sodium intake, mean arterial blood pressure and sodium excretion, and a reduction of urinary volume. L-NAME pretreatment enhanced the ANG-II response, while L-arginine attenuated VP and OT release, thirst, appetite for sodium, antidiuresis, and natriuresis, as well as pressor responses induced by ANG-II. Discussion and conclusion: Thus, the central nitrergic system participates in the angiotensinergic responses evoked by water deprivation and hypovolemia to refrain neurohypophysial secretion, hydromineral balance, and blood pressure homeostasis.

Effects of Laser on the Synovial Fluid in the Inflammatory Process of the Knee Joint of the Rabbit

Objective: The purpose of this study was to evaluate the effects of low-level laser (LLL) energy on the clinical signs of inflammation and the cellular composition of synovial fluid (SF) in the inflamed knee of the rabbit. Background Data: There are few findings related to the effects of LLL on SF in inflammatory processes and there is little knowledge about the optimal parameters for reducing joint inflammation. Materials and Methods: Inflammation in the right knee of 36 rabbits was induced by intracapsular injection (0.2 mL) of Terebinthina commun (Tc). The animals were randomly assigned to three groups: acute experimental group (AEG), chronic experimental group (CEG), and control group (CG), which only received Tc. Each group was divided in two subgroups of six animals each. The AEG and CEG groups began to receive laser treatment 2 and 5 d after the induction of inflammation, respectively. Laser irradiation at a wavelength of 830 nm, power output of 77 mW, and power density of 27.5 W/cm(2) was applied daily for 7 d for either 0.12 sec or 0.32 sec, resulting in doses of 3.4 J/cm(2) and 8 J/cm(2), respectively. Body mass, joint perimeter, joint temperature, and the morphology of the SF were analyzed. Results: There was no statistically significant differences between groups in the body mass, joint perimeter, and SF morphology. Conclusion: Laser irradiation with the selected parameters produced only a few subtle differences in the inflammatory signs and the SF. The lack of effects may have been due to the short irradiation time.

Association of Trypanosoma vivax in extracellular sites with central nervous system lesions and changes in cerebrospinal fluid in experimentally infected goats

Changes in cerebrospinal fluid (CSF) and anatomical and histopathological central nervous system (CNS) lesions were evaluated, and the presence of Trypanosoma vivax in CNS tissues was investigated through PCR. Twelve adult male goats were divided into three groups (G): G1, infected with T. vivax and evaluated during the acute phase; G2, infected goats evaluated during the chronic phase; and G3, consisting of non-infected goats. Each goat from G1 and G2 was infected with 1.25 x 10(5) trypomastigotes. Cerebrospinal fluid (CSF) analysis and investigation of T. vivax was performed at the 15(th) day post-infection (dpi) in G1 goats and on the fifth day after the manifestation of nervous system infection signs in G2 goats. All goats were necropsied, and CNS fragments from G1 and G2 goats were evaluated by PCR for the determination of T. vivax. Hyperthermia, anemia and parasitemia were observed from the fifth dpi for G1 and G2, with the highest parasitemia peak between the seventh and 21(st) dpi. Nervous system infection signs were observed in three G2 goats between the 30(th) and 35(th) dpi. CSF analysis revealed the presence of T. vivax for G2. Meningitis and meningoencephalitis were diagnosed in G2. PCR were positive for T. vivax in all the samples tested. In conclusion, T. vivax may reach the nervous tissue resulting in immune response from the host, which is the cause of progressive clinical and pathological manifestations of the CNS in experimentally infected goats.

Museum, object and information

This text aims to approach museums` role in the production of knowledge and how objects are transformed into documents when museums incorporate them. On accepting the effects of such transformation, museums start working not only with material goods, but also symbolic goods. The collection manager or exhibition curator communicate through documents rather than bringing into light its intrinsic content. In this sense, every process involving museum documents, from the selection of collections to exhibitions, has a rhetoric and ideological nature which is given. Museums must search for meanings through correlations established in the process of producing information. Exhibitions should present objects in multiple contexts, giving visitors the opportunity to participate and attribute their own meanings to them.

On the accuracy of two-fluid model predictions for a particular gas-solid riser flow

Literature presents a huge number of different simulations of gas-solid flows in risers applying two-fluid modeling. In spite of that, the related quantitative accuracy issue remains mostly untouched. This state of affairs seems to be mainly a consequence of modeling shortcomings, notably regarding the lack of realistic closures. In this article predictions from a two-fluid model are compared to other published two-fluid model predictions applying the same Closures, and to experimental data. A particular matter of concern is whether the predictions are generated or not inside the statistical steady state regime that characterizes the riser flows. The present simulation was performed inside the statistical steady state regime. Time-averaged results are presented for different time-averaging intervals of 5, 10, 15 and 20 s inside the statistical steady state regime. The independence of the averaged results regarding the time-averaging interval is addressed and the results averaged over the intervals of 10 and 20 s are compared to both experiment and other two-fluid predictions. It is concluded that the two-fluid model used is still very crude, and cannot provide quantitative accurate results, at least for the particular case that was considered. (C) 2009 Elsevier Inc. All rights reserved.

AnSBBR Applied to the Treatment of Metalworking Fluid Wastewater: Effect of Organic and Shock Load

An investigation was performed regarding the application of a mechanically stirred anaerobic sequencing batch biofilm reactor containing immobilized biomass on inert polyurethane foam (AnSBBR) to the treatment of soluble metalworking fluids to remove organic matter and produce methane. The effect of increasing organic matter and reactor fill time, as well as shock load, on reactor stability and efficiency have been analyzed. The 5-L AnSBBR was operated at 30 A degrees C in 8-h cycles, agitation of 400 rpm, and treated 2.0 L effluent per cycle. Organic matter was increased by increasing the influent concentration (500, 1,000, 2,000, and 3,000 mg chemical oxygen demand (COD)/L). Fill times investigated were in the batch mode (fill time 10 min) and fed-batch followed by batch (fill time 4 h). In the batch mode, organic matter removal efficiencies were 87%, 86%, and 80% for influent concentrations of 500, 1,000, and 2,000 mgCOD/L (1.50, 3.12, and 6.08 gCOD/L.d), respectively. At 3,000 mgCOD/L (9.38 gCOD/L.d), operational stability could not be achieved. The reactor managed to maintain stability when a shock load twice as high the feed concentration was applied, evidencing the robustness of the reactor to potential concentration variations in the wastewater being treated. Increasing the fill time to 4 h did not improve removal efficiency, which was 72% for 2,000 mgCOD/L. Thus, gradual feeding did not improve organic matter removal. The concentration of methane formed at 6.08 gCOD/L was 5.20 mmolCH(4), which corresponded to 78% of the biogas composition. The behavior of the reactor during batch and fed-batch feeding could be explained by a kinetic model that considers organic matter consumption, production, and consumption of total volatile acids and methane production.

The influence of immobilized biomass and particle size on the fluid dynamics of an anaerobic fluidized bed reactor

Fluid dynamic analysis is an important branch of several chemical engineering related areas, such as drying processes and chemical reactors. However, aspects concerning fluid dynamics in wastewater treatment bioreactors still require further investigation, as they highly influence process efficiency. Therefore, it is essential to evaluate the influence of biofilm on the reactor fluid dynamic behavior, through the analysis of a few important parameters, such as minimum fluidization velocity, bed expansion and porosity, and particle terminal velocity. The main objective of the present work was to investigate the fluid dynamics of an anaerobic fluidized bed reactor, having activated carbon particles as support media for biomass immobilization. Reactor performance was tested using synthetic residual water, which was prepared using the solution employed in BOD determination. The results showed that the presence of immobilized biomass increased particle density and altered the main fluid dynamic parameters investigated.