2,371 research outputs found
Connexin-dependent neuroglial networking as a new therapeutic target
Astrocytes and neurons dynamically interact during physiological processes, and it is now widely accepted that they are both organized in plastic and tightly regulated networks. Astrocytes are connected through connexin-based gap junction channels, with brain region specificities, and those networks modulate neuronal activities, such as those involved in sleep-wake cycle, cognitive, or sensory functions. Additionally, astrocyte domains have been involved in neurogenesis and neuronal differentiation during development; they participate in the "tripartite synapse" with both pre-synaptic and post-synaptic neurons by tuning down or up neuronal activities through the control of neuronal synaptic strength. Connexin-based hemichannels are also involved in those regulations of neuronal activities, however, this feature will not be considered in the present review. Furthermore, neuronal processes, transmitting electrical signals to chemical synapses, stringently control astroglial connexin expression, and channel functions. Long-range energy trafficking toward neurons through connexin-coupled astrocytes and plasticity of those networks are hence largely dependent on neuronal activity. Such reciprocal interactions between neurons and astrocyte networks involve neurotransmitters, cytokines, endogenous lipids, and peptides released by neurons but also other brain cell types, including microglial and endothelial cells. Over the past 10 years, knowledge about neuroglial interactions has widened and now includes effects of CNS-targeting drugs such as antidepressants, antipsychotics, psychostimulants, or sedatives drugs as potential modulators of connexin function and thus astrocyte networking activity. In physiological situations, neuroglial networking is consequently resulting from a two-way interaction between astrocyte gap junction-mediated networks and those made by neurons. As both cell types are modulated by CNS drugs we postulate that neuroglial networking may emerge as new therapeutic targets in neurological and psychiatric disorders
Mean curvature flow without singularities
We study graphical mean curvature flow of complete solutions defined on
subsets of Euclidean space. We obtain smooth long time existence. The
projections of the evolving graphs also solve mean curvature flow. Hence this
approach allows to smoothly flow through singularities by studying graphical
mean curvature flow with one additional dimension.Comment: 19 pages, 4 figure
Spherically Symmetric Solutions in M\o ller's Tetrad Theory of Gravitation
The general solution of M\o ller's field equations in case of spherical
symmetry is derived. The previously obtained solutions are verified as special
cases of the general solution.Comment: LaTeX2e with AMS-LaTeX 1.2, 8 page
Entomological fauna associated with Aguaribay : Mendoza (Argentina)
En los relevamientos de especias dañinas
y benéficas presentes en el aguaribay
(Schinus molle L. var. Areira), para inventariar
su entomofauna se efectuaron observaciones
en distintas zonas de Mendoza (Argentina)
en 1988/91 y 1994/96, confirmando
y actualizando la bibliografÃa.
Se recolectó material a campo para su
identificación sistemática. Se evaluaron daños
y se los documentó fotográficamente. En
el laboratorio se conservaron muestras con
parasitoides hasta la aparición de adultos
para su clasificación, registrándose 8 especies
de Homoptera, 7 de Hymenoptera, 7 de
Coleoptera, 5 de Lepidoptera, 4 de Diptera,
4 de Thysanoptera, 2 de Hemiptera y 2 de
Neuroptera.
Las principales especies que afectan al
Aguaribay son Calophya sp. (Homoptera -
Psyllidae), Ceroplastes grandis (Homoptera
- Coccidae) y Aphis schinifoliae (Homoptera
- Aphididae). También cuenta con una importante
fauna benéfica: coccinélidos,
parasitoides, sÃrfidos y crisópidos.Pest and beneficial species present in
Schinus molle L. var. Areira were monitoring
in order to obtain an inventory of its entomological
fauna. It was made observations in
different zones of Mendoza from 1988 to 1991,
and then, between 1994 and 1996, it was
confirmed further observations and it was
brought up to day bibliographical revisions. It
was collected material in field in order to made
its systematic identification. Damages were
evaluated and documented photographically.
Samples with parasitoids were stored in
laboratory until the appearance of adults for
their classification. It was registered: 8 species of
Homoptera, 7 of Hymenoptera, 7 of Coleop-tera,
5 of Lepidoptera, 4 of Diptera, 4 of Thysanoptera,
2 of Hemiptera and 2 of Neuroptera.
The main pest are: Calophya sp.
(Homoptera - Psyllidae), Ceroplastes grandis
(Homoptera - Coccidae) and Aphis schinifoliae
(Homoptera - Aphididade). Also, there is an
important beneficial fauna: Coccinellidae,
parasitoids, Syrphidae and Chrysopidae.Fil: Sáez, César C..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Mácola, Guido S..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: Holgado, Miriam G..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias BiológicasFil: GarcÃa Sáez, José G..
Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ciencias Biológica
Vacuum type I spacetimes and aligned Papapetrou fields: symmetries
We analyze type I vacuum solutions admitting an isometry whose Killing
2--form is aligned with a principal bivector of the Weyl tensor, and we show
that these solutions belong to a family of type I metrics which admit a group
of isometries. We give a classification of this family and we study the
Bianchi type for each class. The classes compatible with an aligned Killing
2--form are also determined. The Szekeres-Brans theorem is extended to non
vacuum spacetimes with vanishing Cotton tensor.Comment: 19 pages; a reference adde
Simulador de máquinas de Turing para fines didácticos
Se presenta un programa simulador escrito para ayudar a
los estudiantes a comprender el concepto de máquina de Turing y a probar y corregir sus diseños de algoritmos con esta máquina.
En una primera parte se describe el simulador desde el
punto de vista de su uso, en el que cabe resaltar la representación del esquema funcional en la forma de quÃntuplas, junto a una serie de opciones de explotación.
La segunda y última parte se dedica a las caracterÃsticas
del programa, ocupación de memoria, representación y manejo
de estados internos, simulación de la cinta y otras técnicas
propias del programa o del miniordenador en el que aquel ha sido instrumentado
¿Un sistema educativo comprensivo?
Any good educational system tries to keep the maximum number of students in the educational system for as long as possible, where he or she will receive a quality education which will prepare him or her for higher education and the labour market. In other words, they fight for a comprehensive educational system. The LOMCE is going to achieve the complete opposite. We shall analyze this more deeply in the following paragraphs.
Keywords: Vocational training, higher vocational training, educational method, scholar evaluation, exam, income test, scholar dropout, basic education, secondary education, postsecondary education, higher education, private school, public school.Ningún sistema educativo intenta mantener el máximo número de estudiantes en el sistema educativo durante el mayor tiempo posible, donde el o ella recibirá una educación de calidad la cual los preparará para la educación superior y el mercado
laboral. En otras palabras, ellos luchan por un sistema educativo comprensivo. La
LOMCE va a lograr todo lo contrario. Nosotros analizaremos esto más profundamente
en los siguientes párrafos.ReiDoCrea. Departamento de PsicologÃa Social. Universidad de Granada
Beam deconvolution in noisy CMB maps
The subject of this paper is beam deconvolution in small angular scale CMB
experiments. The beam effect is reversed using the Jacobi iterative method,
which was designed to solved systems of algebraic linear equations. The beam is
a non circular one which moves according to the observational strategy. A
certain realistic level of Gaussian instrumental noise is assumed. The method
applies to small scale CMB experiments in general (cases A and B), but we have
put particular attention on Planck mission at 100 GHz (cases C and D). In cases
B and D, where noise is present, deconvolution allows to correct the main beam
distortion effect and recover the initial angular power spectrum up to the end
of the fifth acoustic peak. An encouraging result whose importance is analyzed
in detail. More work about deconvolution in the presence of other systematics
is in progress.
This paper is related to the Planck LFI activities.Comment: 24 pages, 9 figures. submitted to Astronomy and Astrophysic
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