75 resultados para CONSENSUAL REFLEX
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Purpose: C57/Bl6, Cpfl1-/- (Cone photoreceptors function loss 1; pure rod function), Gnat1alpha-/- (rod alpha-transducin; pure cone function) and Rpe65-/-;Rho-/- double knock-out mice were studied in order to distinguish the respective contributions of the different photoreceptor (PR) systems that enable light perception and mediate a visual reflex in adult Rpe65-/- mice using a simple behavioural procedure. Methods: Visual function was estimated using a rotating automatized optomotor drum covered with vertical black and white stripes at spatial frequencies of 0.025 to 0.5 cycles per degree (cpd) in both photopic and scotopic conditions. To evaluate the contribution as well as the light intensity threshold of each PR system, we tested the mouse strains with different luminances. Results: Stripe rotation elicits head movements in wild-type (WT) animals in photopic and scotopic conditions depending on the spatial frequency, whereas Cpfl1-/- mice show a reduced activity in the photopic condition and Gnat1alpha-/- mice an almost absent response in the scotopic condition. Interestingly, a robust visual response is obtained with Rpe65-/- knockout mice at 0.075 cpd and 0.1 cpd in the photopic condition. The residual rod function in the Rpe65-/- animals was demonstrated by testing Rpe65-/-;Rho-/- mice that present no response in photopic conditions. Conclusions: The optomotor test is a simple method to estimate the visual function, and to evaluate the respective contributions of rod and cone systems. Using this test, we demonstrate that in Rpe65-/- mice, devoid of functional cones and of detectable 11-cis-retinal protein, rods mimic in part the cone function by mediating vision in photopic conditions.
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A painful worsening of known difficulties in walking led us to investigate a man who presented a spastic paraparesis. Radiological investigations had to be repeated three times before making a diagnosis of a right C6 spinal dural arteriovenous fistula after a 22-month follow-up. Knowing the mechanisms leading to spinal venous hypertension may explain the low yield of the early radiological investigations that should be repeated. The efficiency of the treatment depends on the severity of the presurgical neurologic manifestations.
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Age trajectories for personality traits are known to be similar across cultures. To address whether stereotypes of age groups reflect these age-related changes in personality, we asked participants in 26 countries (N = 3,323) to rate typical adolescents, adults, and old persons in their own country. Raters across nations tended to share similar beliefs about different age groups; adolescents were seen as impulsive, rebellious, undisciplined, preferring excitement and novelty, whereas old people were consistently considered lower on impulsivity, activity, antagonism, and Openness. These consensual age group stereotypes correlated strongly with published age differences on the five major dimensions of personality and most of 30 specific traits, using as criteria of accuracy both self-reports and observer ratings, different survey methodologies, and data from up to 50 nations. However, personal stereotypes were considerably less accurate, and consensual stereotypes tended to exaggerate differences across age groups.
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The low GFR of newborns is maintained by various factors including the renin-angiotensin system. We previously established the importance of angiotensin II in the newborn kidney, using the angiotensin-converting enzyme inhibitor perindoprilat. The present study was designed to complement these observations by evaluating the role of angiotensin-type 1 (AT(1)) receptors, using losartan, a specific AT(1)-receptor blocker. Increasing doses of losartan were infused into anesthetized, ventilated, newborn rabbits. Renal function and hemodynamic variables were assessed using inulin and para-aminohippuric acid clearances as markers of GFR and renal plasma flow, respectively. Losartan 0.1 mg/kg slightly decreased mean blood pressure (-11%) and increased diuresis (+22%). These changes can be explained by inhibition of the AT(1)-mediated vasoconstrictive and antidiuretic effects of angiotensin, and activation of vasodilating and diuretic AT(2) receptors widely expressed in the neonatal period. GFR and renal blood flow were not modified. Losartan 0.3 mg/kg decreased mean blood pressure significantly (-15%), probably by inhibiting systemic AT(1) receptors. GFR significantly decreased (-25%), whereas renal blood flow remained stable. The decrease in filtration fraction (-21%) indicates predominant efferent vasodilation. At 3 mg/kg, the systemic hypotensive effect of losartan was marked (mean blood pressure, -28%), with decreased GFR and renal blood flow (-57% and -51%, respectively), a stable filtration fraction, and an increase in renal vascular resistance by 124%. The renal response to this dose can be considered as reflex vasoconstriction of afferent and efferent arterioles, rather than specific receptor antagonism. We conclude that under physiologic conditions, the renin-angiotensin is critically involved in the maintenance of GFR in the immature kidney.
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La gouvernance de l'Internet est une thématique récente dans la politique mondiale. Néanmoins, elle est devenue au fil des années un enjeu économique et politique important. La question a même pris une importance particulière au cours des derniers mois en devenant un sujet d'actualité récurrent. Forte de ce constat, c ette recherche retrace l'histoire de la gouvernance de l'Internet depuis son émergence comme enjeu politique dans les années 1980 jusqu'à la fin du Sommet Mondial sur la Société de l'Information (SMSI) en 2005. Plutôt que de se focaliser sur l'une ou l'autre des institutions impliquées dans la régulation du réseau informatique mondial, cette recherche analyse l'émergence et l'évolution historique d'un espace de luttes rassemblant un nombre croissant d'acteurs différents. Cette évolution est décrite à travers le prisme de la relation dialectique entre élites et non-élites et de la lutte autour de la définition de la gouvernance de l'Internet. Cette thèse explore donc la question de comment les relations au sein des élites de la gouvernance de l'Internet et entre ces élites et les non-élites expliquent l'emergence, l'évolution et la structuration d'un champ relativement autonome de la politique mondiale centré sur la gouvernance de l'Internet. Contre les perspectives dominantes réaliste et libérales, cette recherche s'ancre dans une approche issue de la combinaison des traditions hétérodoxes en économie politique internationale et des apports de la sociologie politique internationale. Celle-ci s'articule autour des concepts de champ, d'élites et d'hégémonie. Le concept de champ, développé par Bourdieu inspire un nombre croissant d'études de la politique mondiale. Il permet à la fois une étude différenciée de la mondialisation et l'émergence d'espaces de lutte et de domination au niveau transnational. La sociologie des élites, elle, permet une approche pragmatique et centrée sur les acteurs des questions de pouvoir dans la mondialisation. Cette recherche utilise plus particulièrement le concept d'élite du pouvoir de Wright Mills pour étudier l'unification d'élites a priori différentes autour de projets communs. Enfin, cette étude reprend le concept néo-gramscien d'hégémonie afin d'étudier à la fois la stabilité relative du pouvoir d'une élite garantie par la dimension consensuelle de la domination, et les germes de changement contenus dans tout ordre international. A travers l'étude des documents produits au cours de la période étudiée et en s'appuyant sur la création de bases de données sur les réseaux d'acteurs, cette étude s'intéresse aux débats qui ont suivi la commercialisation du réseau au début des années 1990 et aux négociations lors du SMSI. La première période a abouti à la création de l'Internet Corporation for Assigned Names and Numbers (ICANN) en 1998. Cette création est le résultat de la recherche d'un consensus entre les discours dominants des années 1990. C'est également le fruit d'une coalition entre intérêts au sein d'une élite du pouvoir de la gouvernance de l'Internet. Cependant, cette institutionnalisation de l'Internet autour de l'ICANN excluait un certain nombre d'acteurs et de discours qui ont depuis tenté de renverser cet ordre. Le SMSI a été le cadre de la remise en cause du mode de gouvernance de l'Internet par les États exclus du système, des universitaires et certaines ONG et organisations internationales. C'est pourquoi le SMSI constitue la seconde période historique étudiée dans cette thèse. La confrontation lors du SMSI a donné lieu à une reconfiguration de l'élite du pouvoir de la gouvernance de l'Internet ainsi qu'à une redéfinition des frontières du champ. Un nouveau projet hégémonique a vu le jour autour d'éléments discursifs tels que le multipartenariat et autour d'insitutions telles que le Forum sur la Gouvernance de l'Internet. Le succès relatif de ce projet a permis une stabilité insitutionnelle inédite depuis la fin du SMSI et une acceptation du discours des élites par un grand nombre d'acteurs du champ. Ce n'est que récemment que cet ordre a été remis en cause par les pouvoirs émergents dans la gouvernance de l'Internet. Cette thèse cherche à contribuer au débat scientifique sur trois plans. Sur le plan théorique, elle contribue à l'essor d'un dialogue entre approches d'économie politique mondiale et de sociologie politique internationale afin d'étudier à la fois les dynamiques structurelles liées au processus de mondialisation et les pratiques localisées des acteurs dans un domaine précis. Elle insiste notamment sur l'apport de les notions de champ et d'élite du pouvoir et sur leur compatibilité avec les anlayses néo-gramsciennes de l'hégémonie. Sur le plan méthodologique, ce dialogue se traduit par une utilisation de méthodes sociologiques telles que l'anlyse de réseaux d'acteurs et de déclarations pour compléter l'analyse qualitative de documents. Enfin, sur le plan empirique, cette recherche offre une perspective originale sur la gouvernance de l'Internet en insistant sur sa dimension historique, en démontrant la fragilité du concept de gouvernance multipartenaire (multistakeholder) et en se focalisant sur les rapports de pouvoir et les liens entre gouvernance de l'Internet et mondialisation. - Internet governance is a recent issue in global politics. However, it gradually became a major political and economic issue. It recently became even more important and now appears regularly in the news. Against this background, this research outlines the history of Internet governance from its emergence as a political issue in the 1980s to the end of the World Summit on the Information Society (WSIS) in 2005. Rather than focusing on one or the other institution involved in Internet governance, this research analyses the emergence and historical evolution of a space of struggle affecting a growing number of different actors. This evolution is described through the analysis of the dialectical relation between elites and non-elites and through the struggle around the definition of Internet governance. The thesis explores the question of how the relations among the elites of Internet governance and between these elites and non-elites explain the emergence, the evolution, and the structuration of a relatively autonomous field of world politics centred around Internet governance. Against dominant realist and liberal perspectives, this research draws upon a cross-fertilisation of heterodox international political economy and international political sociology. This approach focuses on concepts such as field, elites and hegemony. The concept of field, as developed by Bourdieu, is increasingly used in International Relations to build a differentiated analysis of globalisation and to describe the emergence of transnational spaces of struggle and domination. Elite sociology allows for a pragmatic actor-centred analysis of the issue of power in the globalisation process. This research particularly draws on Wright Mill's concept of power elite in order to explore the unification of different elites around shared projects. Finally, this thesis uses the Neo-Gramscian concept of hegemony in order to study both the consensual dimension of domination and the prospect of change contained in any international order. Through the analysis of the documents produced within the analysed period, and through the creation of databases of networks of actors, this research focuses on the debates that followed the commercialisation of the Internet throughout the 1990s and during the WSIS. The first time period led to the creation of the Internet Corporation for Assigned Names and Numbers (ICANN) in 1998. This creation resulted from the consensus-building between the dominant discourses of the time. It also resulted from the coalition of interests among an emerging power elite. However, this institutionalisation of Internet governance around the ICANN excluded a number of actors and discourses that resisted this mode of governance. The WSIS became the institutional framework within which the governance system was questioned by some excluded states, scholars, NGOs and intergovernmental organisations. The confrontation between the power elite and counter-elites during the WSIS triggered a reconfiguration of the power elite as well as a re-definition of the boundaries of the field. A new hegemonic project emerged around discursive elements such as the idea of multistakeholderism and institutional elements such as the Internet Governance Forum. The relative success of the hegemonic project allowed for a certain stability within the field and an acceptance by most non-elites of the new order. It is only recently that this order began to be questioned by the emerging powers of Internet governance. This research provides three main contributions to the scientific debate. On the theoretical level, it contributes to the emergence of a dialogue between International Political Economy and International Political Sociology perspectives in order to analyse both the structural trends of the globalisation process and the located practices of actors in a given issue-area. It notably stresses the contribution of concepts such as field and power elite and their compatibility with a Neo-Gramscian framework to analyse hegemony. On the methodological level, this perspective relies on the use of mixed methods, combining qualitative content analysis with social network analysis of actors and statements. Finally, on the empirical level, this research provides an original perspective on Internet governance. It stresses the historical dimension of current Internet governance arrangements. It also criticise the notion of multistakeholde ism and focuses instead on the power dynamics and the relation between Internet governance and globalisation.
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We compared the pupil responses originating from outer versus inner retinal photoreception between patients with isolated hereditary optic neuropathy (HON, n = 8) and healthy controls (n = 8). Three different testing protocols were used. For the first two protocols, a response function of the maximal pupil contraction versus stimulus light intensity was generated and the intensity at which half of the maximal pupil contraction, the half-max intensity, was determined. For the third protocol, the pupil size after light offset, the re-dilation rate and re-dilation amplitude were calculated to assess the post-light stimulus response. Patients with HON had bilateral, symmetric optic atrophy and significant reduction of visual acuity and visual field compared to controls. There were no significant mean differences in the response curve and pupil response parameters that reflect mainly rod, cone or melanopsin activity between patients and controls. In patients, there was a significant correlation between the half-max intensity of the red light sequence and visual field loss. In conclusion, pupil responses derived from outer or inner retinal photoreception in HON patients having mild-to moderate visual dysfunction are not quantitatively different from age-matched controls. However, an association between the degree of visual field loss and the half-max intensity of the cone response suggests that more advanced stages of disease may lead to impaired pupil light reflexes.
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OBJECTIVE: In contrast to conventional (CONV) neuromuscular electrical stimulation (NMES), the use of "wide-pulse, high-frequencies" (WPHF) can generate higher forces than expected by the direct activation of motor axons alone. We aimed at investigating the occurrence, magnitude, variability and underlying neuromuscular mechanisms of these "Extra Forces" (EF). METHODS: Electrically-evoked isometric plantar flexion force was recorded in 42 healthy subjects. Additionally, twitch potentiation, H-reflex and M-wave responses were assessed in 13 participants. CONV (25Hz, 0.05ms) and WPHF (100Hz, 1ms) NMES consisted of five stimulation trains (20s on-90s off). RESULTS: K-means clustering analysis disclosed a responder rate of almost 60%. Within this group of responders, force significantly increased from 4% to 16% of the maximal voluntary contraction force and H-reflexes were depressed after WPHF NMES. In contrast, non-responders showed neither EF nor H-reflex depression. Twitch potentiation and resting EMG data were similar between groups. Interestingly, a large inter- and intrasubject variability of EF was observed. CONCLUSION: The responder percentage was overestimated in previous studies. SIGNIFICANCE: This study proposes a novel methodological framework for unraveling the neurophysiological mechanisms involved in EF and provides further evidence for a central contribution to EF in responders.
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Drawing on an analysis of austerity reforms in Greece and Portugal during the sovereign debt crisis from 2009 onwards, we show how the nature of the linkages between parties and citizens shapes party strategies of fiscal retrenchment. We argue that parties which rely to a greater extent on the selective distribution of state resources to mobilize electoral support (clientelistic linkages) are more reluctant to agree to fiscal retrenchment because their own electoral survival depends on their ability to control state budgets to reward clients. In Greece, where parties relied extensively on these clientelistic linkages, austerity reforms have been characterized by recurring conflicts and disagreements between the main parties, as well as a fundamental transformation of the party system. By contrast, in Portugal, where parties relied less on clientelistic strategies, austerity reforms have been more consensual because fiscal retrenchment challenged to a lesser extent the electoral base of the mainstream parties.
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The number of qualitative research methods has grown substantially over the last twenty years, both in social sciences and, more recently, in the health sciences. This growth came with questions on the quality criteria needed to evaluate this work, and numerous guidelines were published. The latters include many discrepancies though, both in their vocabulary and construction. Many expert evaluators decry the absence of consensual and reliable evaluation tools. The authors present the results of an evaluation of 58 existing guidelines in 4 major health science fields (medicine and epidemiology; nursing and health education; social sciences and public health; psychology / psychiatry, research methods and organization) by expert users (article reviewers, experts allocating funds, editors, etc.). The results propose a toolbox containing 12 consensual criteria with the definitions given by expert users. They also indicate in which disciplinary field each type of criteria is known to be more or less essential. Nevertheless, the authors highlight the limitations of the criteria comparability, as soon as one focuses on their specific definitions. They conclude that each criterion in the toolbox must be explained to come to broader consensus and identify definitions that are consensual to all the fields examined and easily operational.
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With qualitative methods being increasingly used in health science fields, numerous grids proposing criteria to evaluate the quality of this type of research have been produced. Expert evaluators deem that there is a lack of consensual tools to evaluate qualitative research. Based on the review of 133 quality criteria grids for qualitative research in health sciences, the authors present the results of a computerized lexicometric analysis, which confirms the variety of intra- and inter-grid constructions, including within the same field. This variety is linked to the authors' paradigmatic references underlying the criteria proposed. These references seem to be built intuitively, reflecting internal representations of qualitative research, thus making the grids and their criteria hard to compare. Consequently, the consensus on the definitions and the number of criteria becomes problematic. The paradigmatic and theoretical references of the grids should be specified so that users could better assess their contributions and limitations.
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This report compares policy learning processes in 11 European countries. Based on the country reports that were produced by the national teams of the INSPIRES project, this paper develops an argument that connects problem pressure and politicization to learning in different labor market innovations. In short, we argue that learning efforts are most likely to impact on policy change if there is a certain problem pressure that clearly necessitates political action. On the other hand, if problem pressure is very low, or so high that governments need to react immediately, chances are low that learning impacts on policy change. The second part of our argument contends that learning impacts on policy change especially if a problem is not very politicized, i.e. there are no main conflicts concerning a reform, because then, solutions are wound up in the search for a compromise. Our results confirm our first hypothesis regarding the connection between problem pressure and policy learning. Governments learn indeed up to a certain degree of problem pressure. However, once political action becomes really urgent, i.e. in anti-crisis policies, there is no time and room for learning. On the other hand, learning occurred independently from the politicization of problem. In fact, in countries that have a consensual political system, learning occurred before the decision on a reform, whereas in majoritarian systems, learning happened after the adoption of a policy during the process of implementation.
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Neuronal circuit asymmetries are important components of brain circuits, but the molecular pathways leading to their establishment remain unknown. Here we found that the mutation of FRMD7, a gene that is defective in human congenital nystagmus, leads to the selective loss of the horizontal optokinetic reflex in mice, as it does in humans. This is accompanied by the selective loss of horizontal direction selectivity in retinal ganglion cells and the transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. In wild-type retinas, we found FRMD7 specifically expressed in starburst amacrine cells, the interneuron type that provides asymmetric inhibition to direction-selective retinal ganglion cells. This work identifies FRMD7 as a key regulator in establishing a neuronal circuit asymmetry, and it suggests the involvement of a specific inhibitory neuron type in the pathophysiology of a neurological disease. VIDEO ABSTRACT.
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The aim of this study was to prospectively assess the prevalence of orthoptic anomalies following conservative management of pure blowout orbital fractures and to evaluate their clinical relevance. Clinical and radiologic data of patients with unilateral conservatively managed pure blowout orbital fractures with a minimum follow-up of 6 months were reviewed. Eligible patients were contacted and invited to undergo an extended ophthalmologic examination as follows: distance and near visual acuities, Hertel exophthalmometry, corneal light reflex (Hirschberg test), ductions and versions in the 6 cardinal fields of gaze, eye deviation with prisms and alternate cover test in all of the 9-gaze directions with Maddox rod, degrees of incyclo/excyclotorsion with right and left eye fixation, horizontal and vertical deviation with Hess-Weiss coordimetry, degree of horizontal/vertical and incyclo/excyclotorsion deviation with Harms wall deviometry, and vertical deviation with Bielschowsky head-tilt test. Of the 69 patients contacted, 49 declined to participate given that they were asymptomatic. Twenty patients agreed to undergo the examination. One patient complained of minimal double vision limited to the extreme downgaze. Four patients had asymptomatic ocular motility disturbances limited to the extreme gaze. Seven patients had asymptomatic horizontal heterophoria. These disturbances did not interfere with daily or professional activities in any of the patients. The current study demonstrated that conservative management of pure orbital blowout fractures can result in orthoptic anomalies. These sequelae were restricted to a very limited portion of the binocular field of the vision and were not found to be clinically relevant.
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PURPOSE: This study aims to identify which aspects of the pupil light reflex are most influenced by rods and cones independently by analyzing pupil recordings from different mouse models of photoreceptor deficiency. METHODS: One-month-old wild type (WT), rodless (Rho-/-), coneless (Cnga3-/-), or photoreceptor less (Cnga3-/-; Rho-/- or Gnat1-/-) mice were subjected to brief red and blue light stimuli of increasing intensity. To describe the initial dynamic response to light, the maximal pupillary constriction amplitudes and the derivative curve of the first 3 seconds were determined. To estimate the postillumination phase, the constriction amplitude at 9.5 seconds after light termination was related to the maximal constriction amplitude. RESULTS: Rho-/- mice showed decreased constriction amplitude but more prolonged pupilloconstriction to all blue and red light stimuli compared to wild type mice. Cnga3-/- mice had constriction amplitudes similar to WT however following maximal constriction, the early and rapid dilation to low intensity blue light was decreased. To high intensity blue light, the Cnga3-/- mice demonstrated marked prolongation of the pupillary constriction. Cnga3-/-; Rho-/- mice had no pupil response to red light of low and medium intensity. CONCLUSIONS: From specific gene defective mouse models which selectively voided the rod or cone function, we determined that mouse rod photoreceptors are highly contributing to the pupil response to blue light stimuli but also to low and medium red stimuli. We also observed that cone cells mainly drive the partial rapid dilation of the initial response to low blue light stimuli. Thus photoreceptor dysfunction can be derived from chromatic pupillometry in mouse models.