Signs of spatial neglect in unilateral peripheral vestibulopathy

Background and purpose In this study, the question of whether egocentric representation of space is impaired in chronic unilateral vestibulopathies was examined. The objective was to test current theories attributing a predominant role to vestibular afferents in spatial cognition and to assess whether representational neglect signs are common in peripheral vestibular loss. Methods The subjective straight-ahead (SSA) direction was investigated using a horizontal rod allowing the translation and rotation components of the body midline representation to be dissociated in 21 patients with unilateral vestibular loss (right, 13; left, eight) and in 12 healthy controls. Results Compared to the controls, the patients with unilateral vestibulopathy showed a translation bias of their SSA, without rotation bias. The translation bias was not lateralized towards the lesioned side as typically found for biases reported after unilateral vestibular loss. Rather, the SSA bias was rightward whatever the side of the vestibular loss. The translation bias correlated with the vestibular loss, as measured by caloric response and vestibulo-ocular reflex gain, but not with the subjective visual vertical or the residual spontaneous nystagmus. Conclusion The present data suggest that the dysfunctions of neural networks involved in egocentred and allocentred representations of space are differentially compensated for in unilateral vestibular defective patients. In particular, they suggest that asymmetrical vestibular inputs to cortical regions lead to representational spatial disturbances as does defective cortical processing of vestibular inputs in spatial neglect after right hemisphere stroke. They also highlight the predominant role of symmetrical and unaltered vestibular inputs in spatial cognition

Les variations paléoenvironnementales de 1000 avant à 1000 après J.C. et la question des « optima » climatiques de l’Antiquité tardive et du Moyen Âge sur le piémont des Alpes du nord à Colletière, lac de Paladru, France

L’étude pluridisciplinaire (sédimentologie, analyse d’image à l’ordinateur, algologie, palynologie) conduite sur une séquence microlaminée de craies lacustres, prélevée sur le site archéologique médiéval immergé de Colletière (lac de Paladru, près de Grenoble), permet de reconstituer les variations hydrologiques et climatiques de 1000 avant J.C. à 1000 après J.C. sur le piémont des Préalpes occidentales françaises. Les fluctuations bathymétriques peuvent être identifiées avec un haut niveau de résolution chronologique. Sont notés trois importants mouvements régressifs, de 890-895 à 1040 ap. J.C. (entrecoupé d’un court épisode transgressif), de 500/400 à 750-700. ap. J.C., aux IXe-Xe siècles av. J.C., et une longue période à niveaux globalement hauts du lac, du Ve-VIe siècles av. J.C. au IVe-Ve siècles ap. J.C. L’influence anthropique se manifeste faiblement au Bronze Final puis disparaît totalement durant les deux Ages du Fer et la période gallo-romaine. Les témoignages d’activités humaines sur le bassin versant du lac s’amplifient entre les Ve et VIIIe siècles de notre ère, puis culminent vers l’An Mil. La confrontation des données recueillies entre Rhône et Alpes dans les milieux lacustres, fluviaux et terrestres, conduit à mieux apprécier les effets du climat sur chacun d’eux. L’amélioration climatique centrée sur 500 ap. J.C. (l’optimum de l’Antiquité tardive), et celle de l’an Mil après J.C. (l’optimum médiéval) sont plus particulièrement examinées. Celle qui couvre la fin du haut Moyen Âge, de 890 à 1040 a. J.C., se révèle plus prononcée dans ses conséquences sur les milieux continentaux, cela étant aussi le résultat des conditions climatiques qui l’ont précédé, un résultat d’effets successifs. Le rythme et l’ordre des évènements sont aussi importants que le caractère propre de chacun.A multiproxy study (sedimentology, image computer analysis, algology and palynology) led on a microlaminated lacustrine chalk cored from the medieval archaeological site of Colletière immersed on Paladru lake shore (near Grenobla) provides a palaeohydrological and palaeoclimatic reconstruction from 1000 BC to 1000 AD. Lake level fluctuations are recorded with a very high time resolution. Three important regressive levels are registered from 890-895 to 1040 AD (interrupted by a short transgressive episode), from 500/400 to 750-700 AD, in the IXth-Xth centuries BC, and a long period with high lake levels, V-VIth centuries BC to IV-Vth centuries AD. Anthropogenic signals are very weak during late Bronze age period and quite non existent during Iron age and roman period. Evidences of human activity on slopes increase between the Vth and VIIIth century AD, and are the highest around 1000 AD. Comparisons with data from regional lacustrine, fluvial and terrestrial environments allow a better understanding of climatic effects. The late Antiquity climatic optimum around 500 AD and the medieval climatic optimum are more specifically examined. The last one, from 890 to 1040 AD appears to be the most well-marked concerning its consequences on continental environments, but depending also on the pre-existing climatic conditions and on their succession. Rhythm and order of events is as important as their peculiar characteristics

Functional Neuroanatomy of Vertical Visual Perception in Humans

Vertical representation is central to posture control, as well as to spatial perception and navigation. This representation has been studied for a long time in patients with vestibular disorders and more recently in patients with hemispheric damage, in particular in those with right lesions causing spatial or postural deficits. The aim of the study was to determine the brain areas involved in the visual perception of the vertical. Sixteen right-handed healthy participants were evaluated using fMRI while they were judging the verticality of lines or, in a control task, the color of the same lines. The brain bases of the vertical perception proved to involve a bilateral temporo-occipital and parieto-occipital cortical network, with a right dominance tendency, associated with cerebellar and brainstem areas. Consistent with the outcomes of neuroanatomical studies in stroke patients, The data of this original fMRI study in healthy subjects provides new insights into brain networks associated with vertical perception which is typically impaired in both vestibular and spatial neglect patients. Interestingly, these networks include not only brain areas associated with postural control but also areas implied in body representation

Episturmian words: a survey

In this paper, we survey the rich theory of infinite episturmian words which generalize to any finite alphabet, in a rather resembling way, the well-known family of Sturmian words on two letters. After recalling definitions and basic properties, we consider episturmian morphisms that allow for a deeper study of these words. Some properties of factors are described, including factor complexity, palindromes, fractional powers, frequencies, and return words. We also consider lexicographical properties of episturmian words, as well as their connection to the balance property, and related notions such as finite episturmian words, Arnoux-Rauzy sequences, and "episkew words" that generalize the skew words of Morse and Hedlund.Comment: 36 pages; major revision: improvements + new material + more reference

Lupine and zig-zag lines: queer affects in Alain Guiraudie’s L’inconnu du lac and Rester vertical

In this article I investigate how a theory of becomings-animal operates in a number of contemporary queer French films by director Alain Guiraudie (L’inconnu du lac (2013) and Rester vertical (2016)). In particular I explore how a becomings-animal’s association with a Deleuzian theory of affect enhances our understanding of queer intimacy. The aim of this article is to reposition queer intimacy as an ontology outside – outside synthetic and vertical lines of filiation and kinship and inside the disjunctive lines of the outside (what is irregular, random, rural, cosmic). Drawing at first on intimacy as an ontological non-relationality (Bersani 2008; 2009) and on the idea of separation as an ontological necessity of queer intimacy (John Paul Ricco 2017), I want to rethink queer intimacy as exposure outwards – an intimacy to and towards. Within this exteriorization of intimacy, my methodology will rely on the affective power of a Deleuzian theory of lines

Éléments unipotents et sous-groupes paraboliques de groupes réductifs: I

info:eu-repo/semantics/publishe

Mémoire hygiénique sur la dorure au feu des pièces de montres dans le canton de Neuchâtel : lu en 1844, à la Société des Sciences Naturelles de Neuchâtel

par le Dr. Bore

Compléments à l'article :"Groupes réductifs"

Comments on A. Borel and J. Tits, Groupes réductifs,Publ. Math. I.H.E.S.27 (1965), 55–151.info:eu-repo/semantics/publishe