oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 2 )

2018 ( 14 )

2017 ( 12 )

2016 ( 20 )

Custom range...

Search Results: 1 - 10 of 7941 matches for " Alvarez Lopez "
All listed articles are free for downloading (OA Articles)
Page 1 /7941
Display every page Item
Space-Temporal Presence of the Cirripede Parasite Loxothylacus texanus in the Lagoon-Estuarine Subsystem of Alvarado, Veracruz, Mexico
Horacio Vazquez-Lopez,Fernando Alvarez
International Journal of Zoological Research , 2007,
Abstract: The rhizocephalan Loxothylacus texanus, parasite of the crabs Callinectes sapidus and C. rathbunae, appears mainly in the Gulf of Mexico where important economic losses have been attributed to this parasite. The main objective of this study was to explain parasite-host relationship in time and space. A total of 756 organisms were collected, from which there were obtained 545 healthy crabs (72%), 32 feminized males (4.23%), 51 with virgin externa (6.74%), 31 with immature externa (4.1%) and 97 organisms with mature externa (12.8%). It was calculated a sexual proportion of the healthy organisms of 54.86% (299) for the males and 45.14% (246) for the females (sex ratio 1.2:1.0). For the parasitized organisms it was calculated a proportion of 50.24% (106 crabs) for the males and 49.76% (105 crabs) for the females (sex ratio 1.0:1.0). It can be concluded that L. texanus is persistent in time and space in the lagunar subsystem of Alvarado, Veracruz. Its prevalence is greater in dry seasons and in salinities higher than 8, but lower than 24. L. texanus is distributed in an isolated manner inside the lagoon, which allows that the zones with salinities other than 8-24 can serve as refuges to the megalopas and the early stages of C. rathbunae from this rhizocephalan. L. texanus is not selective in regard to the hosts sex. The degree of development of the externa affects the osmoregulatory capacity of the host on benefit of the parasite.
Adiabatic limits and spectral sequences for Riemannian foliations
Jesus A. Alvarez Lopez,Yuri A. Kordyukov
Mathematics , 1999,
Abstract: For general Riemannian foliations, spectral asymptotics of the Laplacian is studied when the metric on the ambient manifold is blown up in directions normal to the leaves (adiabatic limit). The number of ``small'' eigenvalues is given in terms of the differentiable spectral sequence of the foliation. The asymptotics of the corresponding eigenforms also leads to a Hodge theoretic description of this spectral sequence. This is an extension of results of Mazzeo-Melrose and R. Forman.
Long time behavior of leafwise heat flow for Riemannian foliations
Jesus A. Alvarez Lopez,Yuri A. Kordyukov
Mathematics , 1996,
Abstract: For any Riemannian foliation F on a closed manifold M with an arbitrary bundle-like metric, leafwise heat flow of differential forms is proved to preserve smoothness on M at infinite time. This result and its proof have consequences about the space of bundle-like metrics on M, about the dimension of the space of leafwise harmonic forms, and mainly about the second term of the differentiable spectral sequence of F.
Lefschetz distribution of Lie foliations
Jesus A. Alvarez Lopez,Yuri A. Kordyukov
Mathematics , 2007,
Abstract: Let $\mathcal F$ be a Lie foliation on a closed manifold $M$ with structural Lie group $G$. Its transverse Lie structure can be considered as a transverse action $\Phi$ of $G$ on $(M,\mathcal F)$; i.e., an ``action'' which is defined up to leafwise homotopies. This $\Phi$ induces an action $\Phi^*$ of $G$ on the reduced leafwise cohomology $\bar H(\mathcal F)$. By using leafwise Hodge theory, the supertrace of $\Phi^*$ can be defined as a distribution $L_{dis}(\mathcal F)$ on $G$ called the Lefschetz distribution of $\mathcal F$. A distributional version of the Gauss-Bonett theorem is proved, which describes $L_{dis}(\mathcal F)$ around the identity element. On any small enough open subset of $G$, $L_{dis}(\mathcal F)$ is described by a distributional version of the Lefschetz trace formula.
Action graphs and Catalan numbers
Gerardo Alvarez,Julia E. Bergner,Ruben Lopez
Mathematics , 2015,
Abstract: We introduce an inductively defined sequence of directed graphs and prove that the number of edges added at step $k$ is equal to the $k$th Catalan number. Furthermore, we establish an isomorphism between the set of edges adjoined at step $k$ and the set of planar rooted trees with $k$ edges.
La discectomía percutánea en la hernia discal lumbar
ALVAREZ CAMBRAS,RODRIGO; LOPEZ ALVAREZ,ARTURO; LOPEZ HERNANDEZ,FERMIN; REMON DAVILA,XIOMARA;
Revista Cubana de Ortopedia y Traumatolog?-a , 1995,
Abstract: se realizó un estudio descriptivo, retro y prospectivo, de 90 pacientes operados de hernia discal lumbar por el método de la discectomía percutánea posterolateral semiautomatizada, en el período comprendido de septiembre de 1991 a marzo de 1994. los datos fueron tomados de las historias clínicas de estos pacientes, así como de entrevistas personales con ellos. correspondieron al sexo masculino 71 pacientes y 19 al femenino. predominó el grupo de edad comprendido entre 31 y 40 a?os (31,1 %). de 96 espacios intervertebrales intervenidos, el nivel de herniación fue más significativo en el espacio l4-l5, con 52 casos (54.2 %). se les realizó un seguimiento posoperatorio, durante el cual se evaluó el dolor como síntoma fundamental; 47 pacientes (52,2 %) obtuvieron un alivio completo de aquél. la hernia recurrente fue la complicación que más se presentó, con un total de 16 pacientes (17,7 %). en el transcurso de un a?o, en 72 pacientes (80 %) se obtuvieron resultados favorables. sólo 18 (20 %) tuvieron un resultado no favorable después de aplicada la técnica. el tiempo de recuperación de los pacientes con resultados favorables fue de sólo tres meses, aproximadamente.
La discectomía percutánea en la hernia discal lumbar
RODRIGO ALVAREZ CAMBRAS,ARTURO LOPEZ ALVAREZ,FERMIN LOPEZ HERNANDEZ,XIOMARA REMON DAVILA
Revista Cubana de Ortopedia y Traumatolog?-a , 1995,
Abstract: Se realizó un estudio descriptivo, retro y prospectivo, de 90 pacientes operados de hernia discal lumbar por el método de la discectomía percutánea posterolateral semiautomatizada, en el período comprendido de septiembre de 1991 a marzo de 1994. Los datos fueron tomados de las historias clínicas de estos pacientes, así como de entrevistas personales con ellos. Correspondieron al sexo masculino 71 pacientes y 19 al femenino. Predominó el grupo de edad comprendido entre 31 y 40 a os (31,1 %). De 96 espacios intervertebrales intervenidos, el nivel de herniación fue más significativo en el espacio L4-L5, con 52 casos (54.2 %). Se les realizó un seguimiento posoperatorio, durante el cual se evaluó el dolor como síntoma fundamental; 47 pacientes (52,2 %) obtuvieron un alivio completo de aquél. La hernia recurrente fue la complicación que más se presentó, con un total de 16 pacientes (17,7 %). En el transcurso de un a o, en 72 pacientes (80 %) se obtuvieron resultados favorables. Sólo 18 (20 %) tuvieron un resultado no favorable después de aplicada la técnica. El tiempo de recuperación de los pacientes con resultados favorables fue de sólo tres meses, aproximadamente.
Teoría de la empresa bajo incertidumbre con mercado de futuros: el papel de los costes fijos y de un impuesto sobre los beneficios
Alvarez Lopez, Alberto A.,Rodr?guez Puerta, Inmaculada
Rect@ , 2009,
Abstract: El modelo “seminal”, para la empresa competitiva bajo incertidumbre en el precio, presentado por Sandmo (1971) es ampliado por Holthausen (1979) considerando un mercado de futuros para el bien producido por la empresa. En este articulo examinamos dos aspectos no estudiados en el trabajo de Holthausen: el efecto de una variacion en los costes fijos y la consideracion de un impuesto sobre los beneficios. Asimismo, utilizamos para ello una metodologia distinta a la del autor, la cual es una generalizacion y ampliacion de Lippman y McCall (1982). ABSTRACT The seminal model for the competitive firm under price uncertainty presented by Sandmo (1971) is enhanced by Holthausen (1979) by introducing a forward market for the output produced by the firm. This paper examines two aspects not studied in Holthausen’s paper: the effect of a variation in fixed costs and the consideration of aprofit tax. In addition, we use methods of proof different from those of Holthausen's our methods generalize and enhance those of Lippman y McCall (1982).
Observations on the Behavior of the Dark Crab Callinectes rathbunae Contreras Parasitized with the Rhizocephalan Loxothylacus texanus Boschma
H. Vazquez-lopez,F. Alvarez,J. Franco,A. Moran
International Journal of Zoological Research , 2006,
Abstract: One hundred and fourty nine crabs of the species Callinectes rathbunae Contreras parasitized with the rhizocephalan Loxothylacus texanus Boschma were captured. The average shell width was 8.48 cm. Three types of externa were registered in the hosts: virgin, immature and mature externa; their number varied from one to four, being more common the crabs with one externa. The behavior of parasitized crabs was registered during six months. The most aggressive crabs were those that presented virgin externa (n = 82), while the less aggressive ones were those who presented three to four mature externa (n = 3). The crabs with virgin and immature externa conserved the capacity of burying themselves, while the organisms with mature externa lost that capacity. The animals with mature externa passed most of the time grooming and oxygenating the externa they carried. The crabs with mature externa presented bigger voracity that the crabs with immature externa. It can be concluded that the level of aggressiveness of the parasitized crabs is related with the degree of development of the externa, the degree of aggressiveness of the parasitized crabs is not related with the sex and mature externa represent a great metabolic load for their hosts.
Ultraviolet behavior of transverse gravity
Enrique Alvarez,Anton F. Faedo,J. J. Lopez-Villarejo
Physics , 2008, DOI: 10.1088/1126-6708/2008/10/023
Abstract: The structure of the divergences for transverse theories of gravity is studied to one-loop order. These theories are invariant only under those diffeomorphisms that enjoy unit Jacobian determinant (TDiff), so that the determinant of the metric transforms as a true scalar instead of a density. Generically, the models include an additional scalar degree of freedom contained in the metric besides the usual spin two component. When the cosmological constant is fine tuned to zero, there are only two theories which are on shell finite, namely the one in which the symmetry is enhanced to the full group of diffeomorphisms, i.e. Einstein's gravity, and another one denoted by WTDiff which enjoys local Weyl invariance. Both of them are free from the additional scalar.
Page 1 /7941
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.