The Lake Erie Program: Monitoring Fish Stock Changes Over Years

The Lake Erie Fisheries Program of the Ontario Ministry of Natural Resources used a stratified sampling design with partial replacement of catch stations from 1987 to 1990 to monitor the fish community. Estimation methodology associated with partial replacement sampling design based on double sampling regression estimates was not suitable for the small sample sizes encountered and for multivariate descriptive study.;An unbiased estimation methodology for detecting changes and for descriptive study has been developed for two or more sampling occasions in either a simple or a stratified statistical population. The methodology for two occasions links well known cases in statistical inference theory, such as the Student t-test, the Satterthwaite t-test and the paired t-test, in a single inference procedure where the previous tests are specific cases. For more than two occasions, the methodology links well known oneway anova between years (independent samples) and the two-way anova with one replicate per cell of a year by unit design (paired samples) in a single inference procedure where the preceding tests are specific cases. Rules for the computation of degrees of freedom for inference are suggested.;A Principal Component Analysis is also suggested to determine principal components with related patterns of change, habitat influences as well as other correlated patterns in the observations. The technique is based on the standardization of the covariance matrix with the sampling variances associated with the estimation methodology developed. This technique is compared with PCA on covariances and on correlations.;The suggested estimation methodology and PCA are applied to Lake Erie fish populations monitored in the area of the lake under study over the 1987-90 period

Wittgenstein ou l'expression de la transcendance

Le travail de Wittgenstein exemplifie la transcendance dont se nourrit la philosophie. En effet, la recherche de fondements à notre langage, par la mise en œuvre d'un idiome logique, génère des préoccupations ontologiques insondables. De même, le désir de créer une grammaire purement descriptive révèle l'arbitraire des critères de l'ordinaire. Enfin, la négation quasi obsessionnelle d'une intériorité active ne fait pas obstacle à son retour dans les thèmes de la volonté, du silence et de l'éthique. L'Éthique dite ineffable et la volonté, dans le sens de Schopenhauer, s'imposent comme les invariants d'un Sujet en marge d'un monde dit sans valeur dans lequel, logique, éthique et esthétique ne peuvent se dire. Ici, le silence de Wittgenstein ouvre sur un non-dit éloquent. En recherchant des fondements ou des règles à notre langage, tout en expulsant certains objets hors du dicible, Wittgenstein exprime le désir de mettre en place un point de vue synoptique sur notre forme de vie. Mais en fait, il se retrouve prisonnier des entrelacs qui relient l'immanence et la transcendance.Ces investigations ne peuvent être dissociées, chez ce contemporain de la naissance de la psychanalyse, d'une attitude tendancielle à la sublimation des problèmes philosophiques sur fond de crise identitaire. Son attitude face aux choix, sa difficulté à donner un assentiment, son rapport ambigu au religieux, au mystique et à l'identité, sont soulignés comme les points aveugles de son expression. Ces thèmes révèlent une transcendance intrinsèque à son œuvre et une résistance forte de la métaphysique.Le travail de Wittgenstein est pris ici comme un exemple paradigmatique de la philosophie analytique, philosophie entrée en conflit contre l'abus d'expressions métaphysiques accusées de nous livrer aux illusions trompeuses.Wittgenstein's work exemplifies transcendence which feeds philosophy. The search for foundations to our language, by the implementation of a logical structure generates unfathomable ontological concerns. Similarly, the dream of a purely descriptive grammar reveals the arbi-trariness of criteria of the ordinary. Finally, the obsessive denial of an active interiority does not preclude his return to willpower, silence and ethical themes. Ethics, as ineffable, and will, in the sense of Schopenhauer, are invariants of a philosophical subject on the sidelines of a world without value, in which, the logical, ethical and aesthetic could not be said. Here, Witt-genstein's silence opens on an eloquent unsaid. Searching for foundations or rules to our lan-guage, while expelling some objects in the indescribable, Wittgenstein expressed the desire to provide a synoptic view of our form of life. In fact, he finds himself prisoner of interlaces between immanence and transcendence.These investigations cannot be separated with this contemporary of the birth of psychoanaly-sis, a trend attitude to the sublimation of philosophical problems on substance of identity cri-sis. His attitude to choice, his difficulty to give consent, his ambiguous report to the religious, the mystic and identity are underlined as blind expression points. These themes reveal an in-herent transcendence in his work and the resistance of the metaphysical.Wittgenstein's work is seen as a paradigm of analytic philosophy, philosophy came into con-flict against the abuse of metaphysical expressions accused of deceptive illusions for us.REIMS-SCD-Bib. electronique (514549901) / SudocSudocFranceF

Sequential difficulty effects in cognitive and sensorimotor tasks: Insights from arithmetic and Fitts' task

International audienceThe present study tested sequential difficulty effects (SDEs) in arithmetic problem solving and Fitts’ aiming task for the same individuals. SDEs refer to poorer performance on current items following harder items relative to after easier items. Young and older adults accomplished a computational estimation task (i.e., finding the approximate products to two digit multiplication problems) and a Fitts aiming task (i.e., performing rapid pointing movements to reach the finish areas). Current items were preceded by two easy or difficult items (i.e., in the repeate precursor condition) or only one easy or difficult item (i.e., in the unrepeated precursor condition). Participants’ performance revealed SDEs in both the arithmetic and the aiming tasks only when the precursor items were repeated. Data also revealed comparable SDEs in both age groups during the arithmetic task, but SDEs only in older adults while participants accomplished the aiming task. These findings have a number of implications for our understanding of mechanisms underlying SDEs and age-related differences in SDEs, as they suggest that SDEs involve both domain general and domain specific mechanisms that are differentially influenced by aging

Etude de l'impact sur pale d'hélicoptère

Le présent article propose une étude de l’endommagement de structures similaires à des tronçons de pales d’hélicoptère soumises à un impact. Il s’agit de structures composites complexes, fabriquées au laboratoire, et impactées par un projectile de 125 g à des vitesses d’impact de 130 m/s. Les essais sont analysés grâce à une acquisition des déformations au cours de l’essai et à une expertise post-mortem de l’éprouvette. Cela a permis de mettre en évidence les différents mécanismes d'endommagement de l'éprouvette. Un travail de modélisation est aussi présenté. Différentes stratégies de modélisation sous éléments finis, à l’échelle macroscopique, permettent ainsi de modéliser ces phénomènes avec des densités de maillage qui ne sont pas pénalisantes lors d'un calcul sur une structure réelle

Recombination-prone bacterial strains form a reservoir from which epidemic clones emerge in agroecosystems

The acquisition of virulence-related genes through horizontal gene transfer can modify the pathogenic profiles of strains and lead to the emergence of new diseases. Xanthomonas arboricola is a bacterial species largely known for the damage it causes to stone and nut fruit trees worldwide. In addition to these host-specific populations called pathovars, many nonpathogenic strains have been identified in this species. Their evolutionary significance in the context of pathogen emergence is unknown. We looked at seven housekeeping genes amplified from 187 pathogenic and nonpathogenic strains isolated from various plants worldwide to analyze population genetics and recombination dynamics. We also examined the dynamics of the gains and losses of genes associated with life history traits (LHTs) during X. arboricola evolution. We discovered that X. arboricola presents an epidemic population structure. Successful pathovars of trees (i.e. pruni, corylina and juglandis) are epidemic clones whose emergence appears to be linked to the acquisition of eight genes coding for Type III effectors. The other strains of this species are part of a recombinant network, within which LHT-associated genes might have been lost. We suggest that nonpathogenic strains, because of their high genetic diversity and propensity for recombination, may promote the emergence of pathogenic strains

Advanced Neuroimaging with Computed Tomography Scanning

International audienceThe x-ray computed tomography (CT) is well known as a useful imaging method and thus CT images have continuingly been used for many applications, especially in medical fields. This book discloses recent advances and new ideas in theories and applications for CT imaging and its analysis. The 16 chapters selected in this book cover not only the major topics of CT imaging and analysis in medical fields, but also some advanced applications for forensic and industrial purposes. These chapters propose state-of-the-art approaches and cutting-edge research results

Cytopathic effects of the cytomegalovirus-encoded apoptosis inhibitory protein vMIA

Replication of human cytomegalovirus (CMV) requires the expression of the viral mitochondria–localized inhibitor of apoptosis (vMIA). vMIA inhibits apoptosis by recruiting Bax to mitochondria, resulting in its neutralization. We show that vMIA decreases cell size, reduces actin polymerization, and induces cell rounding. As compared with vMIA-expressing CMV, vMIA-deficient CMV, which replicates in fibroblasts expressing the adenoviral apoptosis suppressor E1B19K, induces less cytopathic effects. These vMIA effects can be separated from its cell death–inhibitory function because vMIA modulates cellular morphology in Bax-deficient cells. Expression of vMIA coincided with a reduction in the cellular adenosine triphosphate (ATP) level. vMIA selectively inhibited one component of the ATP synthasome, namely, the mitochondrial phosphate carrier. Exposure of cells to inhibitors of oxidative phosphorylation produced similar effects, such as an ATP level reduced by 30%, smaller cell size, and deficient actin polymerization. Similarly, knockdown of the phosphate carrier reduced cell size. Our data suggest that the cytopathic effect of CMV can be explained by vMIA effects on mitochondrial bioenergetics

Early Deformation of Deep Brain Stimulation Electrodes Following Surgical Implantation: Intracranial, Brain, and Electrode Mechanics

IntroductionAlthough deep brain stimulation is nowadays performed worldwide, the biomechanical aspects of electrode implantation received little attention, mainly as physicians focused on the medical aspects, such as the optimal indication of the surgical procedure, the positive and adverse effects, and the long-term follow-up. We aimed to describe electrode deformations and brain shift immediately after implantation, as it may highlight our comprehension of intracranial and intracerebral mechanics.Materials and MethodsSixty electrodes of 30 patients suffering from severe symptoms of Parkinson’s disease and essential tremor were studied. They consisted of 30 non-directional electrodes and 30 directional electrodes, implanted 42 times in the subthalamus and 18 times in the ventrolateral thalamus. We computed the x (transversal), y (anteroposterior), z (depth), torsion, and curvature deformations, along the electrodes from the entrance point in the braincase. The electrodes were modelized from the immediate postoperative CT scan using automatic voxel thresholding segmentation, manual subtraction of artifacts, and automatic skeletonization. The deformation parameters were computed from the curve of electrodes using a third-order polynomial regression. We studied these deformations according to the type of electrodes, the clinical parameters, the surgical-related accuracy, the brain shift, the hemisphere and three tissue layers, the gyration layer, the white matter stem layer, and the deep brain layer (type I error set at 5%).ResultsWe found that the implanted first hemisphere coupled to the brain shift and the stiffness of the type of electrode impacted on the electrode deformations. The deformations were also different according to the tissue layers, to the electrode type, and to the first-hemisphere-brain-shift effect.ConclusionOur findings provide information on the intracranial and brain biomechanics and should help further developments on intracerebral electrode design and surgical issues