21 research outputs found
Experimental lateral wall boundary layer behavior of a differentially rotating split-cylinder flow
The cylindrical wall boundary layer of a closed cylinder split in two halves at the equator is studied experimentally. When these two parts rotate in exact corotation the internal flow is essentially in solid-body rotation at the angular velocity of both halves. When a slight difference between the rotation frequencies is established a secondary flow is created due to the differential rotation between both sides and restricted to the boundary layer. This behavior of the boundary layer is compared with theoretical and numerical results finding the ¿sandwich¿ structure of a Stewartson boundary layer. Time-dependent waves are observed near the cylindrical wall. Their behavior for different values of the control parameters are presented. Finally, a global recirculation mode is also found due to a symmetry-breaking induced between sides that appears because of a slight misalignment of the experimental setup, whose characteristics are compatible with the behavior of a precessing cylinder
CLT in Functional Linear Regression Models
International audienceWe propose in this work to derive a CLT in the functional linear regression model to get confidence sets for prediction based on functional linear regression. The main difficulty is due to the fact that estimation of the functional parameter leads to a kind of ill-posed inverse problem. We consider estimators that belong to a large class of regularizing methods and we first show that, contrary to the multivariate case, it is not possible to state a CLT in the topology of the considered functional space. However, we show that we can get a CLT for the weak topology under mild hypotheses and in particular without assuming any strong assumptions on the decay of the eigenvalues of the covariance operator. Rates of convergence depend on the smoothness of the functional coefficient and on the point in which the prediction is made
Occurrence of acid erosion of the teeth, actinomycosis and polioencephalomalacia in flock of sheep fed wet low pectin citrus pulp
ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries
This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors
On the Instabilities Triggered in Rotating Flows in Closed Cylinders
En este trabajo principalmente experimental, se ha desarrollado un nuevo experimento para estudiar
flujos rotativos. Este experimento consiste en un cilindro dividido en dos partes justo a media altura
para dejar que cada parte rote independientemente.
Para los datos experimentales obtenidos, el cilindro dividido en dos mitades está siempre en régimen
corrotativo con una de las partes rotando un poco más rápido que la otra. Para la obtención del campo
de velocidades experimental, se han usado técnicas ópticas no invasivas.
El flujo medio e instantáneo han sido estudiados dentro del cilindro y comparados con la literatura
cuando es posible. El foco principal se ha puesto en la zona de las capas lÃmites donde las instabilidades
pueden ocurrir ya que la rotación de fondo es suficientemente grande para tener el volumen interno
en casi rotación de sólido rÃgido, confinando las inestabilidades, si es que hay, en las capas lÃmites.
Centrándose en la capa lÃmite de la pared cilÃndrica, se han encontrado estructuras con dependencia
temporal en la componente acimutal del campo de velocidades, mientras que la capa tipo sándwich de
Stewartson se ha encontrado en la componente axial.
Más aún, se ha encontrado un forzado en el flujo en forma de ondas de Kelvin ya que la simetrÃa del
problema se rompe por un pequeño desalineamiento entre lados. Debido a que se realizan experimentos
con una relación de aspectos donde el primer modo de Kelvin resuena, su contribución al flujo no se
puede obviar. El modo de Kelvin encontrado crea un flujo de recirculación global y su comportamiento
se ha descrito usando la teorÃa no viscosa y lineal.
Se ha realizado un análisis modal del cilindro para encontrar modos que no se pueden observar
directamente en el campo experimental de velocidades. Este análisis revela algunos modos y sus
respectivas frecuencias y amplitudes. Se ha realizado una reconstrucción del flujo siguiendo la teorÃa
no viscosa y lineal que corrobora la presencia de los modos encontrados.
Por otro lado, se ha realizado una estancia predoctoral donde se ha estudiado un flujo experimental
dentro de un cilindro en precesión. Este experimento ha mejorado el conocimiento de otra técnica
experimental y de la teorÃa no viscosa. Los experimentos realizados se han comparado con otra teorÃa
más reciente, viscosa y no lineal, encontrando una buena conexión.In this mainly experimental work, a new setup to study rotating flows has been developed. The setup
consists of a cylinder split into two parts just at mid-height to let each part rotate independently.
For the experimental data procured, the split cylinder is always in a corotation regime with one of
the sides rotating slightly faster than the other. For the obtainment of the experimental velocity flow
field, noninvasive optical devices are used.
The mean and instantaneous flow are studied inside the split cylinder and compared with the
literature when possible. The main focus is put on the boundary layers zone where the instabilities
may happen since the background rotation is high enough to have the bulk in almost solid-body rotation,
confining the instabilities, if they occur, on the boundary layers. Regarding the cylindrical wall boundary
layer, time-dependent structures are found on the azimuthal component of the velocity field, whereas
the Stewartson sandwich-like boundary layer is found on the axial component.
Moreover, a forcing of the flow is found in form of Kelvin waves since the symmetry of the problem
is broken because of a little misalignment of the sides. Due to the experimental runs are performed
with a resonant aspect ratio of the first Kelvin mode, its contribution to the flow cannot be neglected.
The Kelvin mode found creates a global recirculation flow and its behavior has been addressed using
the linear inviscous theory.
A modal analysis of the split-cylinder flow is performed to find modes that cannot be observed directly
on the experimental velocity field. This analysis reveals some modes and their respective frequencies
and amplitudes. A reconstruction of the flow following the linear inviscous theory is performed to
corroborate the presence of the found modes.
On the other hand, a pre-doctoral stay has been performed where an experimental flow created
inside a cylinder in precession has been studied. This experiment has improved the knowledge of
another experimental technique and the inviscous theory. The experimental runs performed have been
compared with a more recent nonlinear and viscous theory finding a good agreement
Análisis del valor de la biopsia del ganglio centinela en el melanoma cutáneo
El melanoma cutáneo es una neoplasia cuya incidencia va en aumento en nuestro medio. Presentamos un estudio sobre 1023 casos de esta patologÃa recogidos a lo largo de 20 años, distribuidos en 2 grupos: grupo A tratados antes del 2000, y grupo B tratados después del 2000. Comparamos la supervivencia de ambos grupos en base al cambio de tratamiento por la introducción del estudio del ganglio centinela a partir del año 2000. No observamos diferencias significativas entre los 2 grupos en la supervivencia de los pacientes con melanoma a pesar de realizar tratamientos más conservadores. Por tanto, gracias a la biopsia de ganglio centinela, se pueden evitar un 75% de linfadenectomÃas electivas realizadas en este tipo de patologÃa sin modificar los Ãndices de supervivencia
Not Available
Not AvailableThe fishery and population characteristics of silver pomfret Pampus argenteus (Euphrasen) caught by gillnetters off Veraval
were studied for the period from 2003 to 2007. The average annual landing of P. argenteus was 114.5 t, which contributed
4.5% to the total gill net catches. The period from July to September was the most productive in terms of catch and catch rate.
The length–weight relationship showed that the growth was isometric. The sex ratio was 1.75 in favour of females. Mature
females occurred throughout the year, with maximum during June – November. The length at first maturity of female was
27.5 cm. The von Bertalanffy growth equation was: Lt = 41.57 [1 – e - 0.64 (t + 0.0315)]. The length at first capture (Lc) was 8.2 cm
with recruitment taking place throughout the year with two peaks during February-March and in August. The natural mortality
(M), fishing mortality (F) and total mortality (Z) were 1.20, 2.11 and 3.31 respectively. The exploitation ratio (E) was 0.64.
The Maximum Sustainable Yield (MSY: 90 t) was lower than the average annual catch indicating over-exploitation of the
species. The yield per recruit (Y/R) and biomass per recruit (B/R) was 38.31 g and 18.16 g respectively. An increase in
relative yield by 17.18% would be obtained by decreasing the present level of fishing by 60%.Not Availabl