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Search Results: 1 - 10 of 485824 matches for " P.;Sánchez-González "
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Estructura y composición de la vegetación del Ca?ón del Zopilote, Guerrero, México
ávila Sánchez, P.;Sánchez-González, A.;Catalán Everástico, C.;
Revista Chapingo. Serie ciencias forestales y del ambiente , 2010, DOI: 10.5154/r.rchscfa.2010.02.003
Abstract: an analysis was carried out of the change in the composition and structure of vegetation along an elevation gradient in zopilote canyon, located in the balsas river basin in guerrero. in an altitude range from 450 to 2,800 m, 28 sampling plots were established in five different vegetation types, defined by their physiognomy. within each vegetation type, six 1,000 m2 plots were selected for sampling tree species, and within these a 100 m2 subplot was established for shrubs and two 6 m2 subplots for herbaceous plants. the structural attribute estimated was the relative importance value of each species; cluster analysis was used for classifying vegetation types. in the elevation range studied, 314 species of vascular plants were identified (including four in the nom-059-ecol-2001), in 204 genera and 79 families. the most species-rich families were: asteraceae, fabaceae, burseracea, lamiacaea and euphorbiaceae. five vegetation types were identified: tropical deciduous forest, palm swamp, quercus forest, pinus forest and mountain cloud forest. the close proximity of these different vegetation types is most likely due to the abrupt changes in topographical and climatic conditions in zopilote canyon.
Contexto ambiental y experiencia espacial de envejecer en el lugar: el caso de Granada
Papeles de población , 2009,
Abstract: La investigación analiza los problemas de envejecer en el espacio habitado (vivienda y barrio) para los adultos mayores en la ciudad de Granada (Espa a). La metodología se basa en el análisis de bases de datos, encuestas a las personas ancianas y un sistema de información geográfi ca a escala de distrito, barrio y sección urbana. Los resultados indican que la habitabilidad del contexto ambiental para el adulto mayor en la ciudad está determinada por la experiencia espacial, que relaciona los factores socioeconómicos (ingresos, condiciones de la vivienda, equipamientos) y los factores de subjetividad espacial (proximidad a familiares y vecinos, sentido del lugar, arraigo). Las conclusiones advierten del empeoramiento de los problemas socioespaciales de los adultos mayores ante la falta de planeación gerontológica en las ciudades.
Primary lymph node melanoma. Case presentation.
Torres-Morientes LM, Puente-López G, Keituqwa-Yá?ez T, Sánchez-González F, López-Ríos-Velasco J, Pérez-Holgado V, Pérez-Cidoncha P
Revista de la Sociedad Otorrinolaringológica de Castilla y León, Cantabria y La Rioja , 2012,
Abstract: Melanomas that initially affect the lymph nodes without an identified primary lesion traditionally have been termed unknown origin metastatic melanomas (UOMM). Its etiology or natural history is not well known and there is no unanimous consensus of treatment. Although they are exceptional cases, clinical findings make us consider the existence of a group of melanomas until now regarded as UOMM. The latest theories defined them as true primary melanomas of lymph nodes with a different biological evolution.
Low distortion embeddings into Asplund Banach spaces
Antonín Procházka,Luis Sánchez-González
Mathematics , 2013,
Abstract: We give a simple example of a countable metric space $M$ that does not embed bi-Lipschitz with distortion strictly less than 2 into any Asplund space. Actually, if $M$ embeds with distortion strictly less than 2 to a Banach space $X$, then $X$ contains an isomorphic copy of $\ell_1$. We also show that the space $M$ does not embed with distortion strictly less than $2$ into $\ell_1$ itself but it does embed isometrically into a space that is isomorphic to $\ell_1$.
Low distortion embeddings between $C(K)$ spaces
Antonín Procházka,Luis Sánchez-González
Mathematics , 2014,
Abstract: We show that, for each ordinal $\alpha<\omega_1$, the space $C([0,\omega^\alpha])$ does not embed into $C(K)$ with distortion strictly less than $2$ unless $K^{(\alpha)}\neq \emptyset$.
Efectos de la colaboración con usuarios sobre el tipo de innovación desarrollado
Sánchez-González,Gloria; González-álvarez,Nuria; Nieto Antolín,Mariano;
Innovar , 2008,
Abstract: cooperating with users for developing innovation has currently acquired noteworthy importance in both the academic and business worlds. the proof of this lies in the increasing number of research articles about this topic which have been published in recent years; more firms are now using this strategy for developing innovation. however, many aspects of this phenomenon demand deeper analysis. one such question (constituting the present paper's main objective) concerns studying the effects of cooperating with users in terms of firms' innovation output; the influence of such cooperation on the likelihood of obtaining two types of innovation has thus been analysed: product innovation compared to process innovation. two bivariate probit models and a sample of 11,881 spanish manufacturing firms from 1998- 2005 have been used to demonstrate that cooperating with users in spain, as well as the intensity/continuity of such relationship, has had a positive influence on developing both kinds of innovation.
Análisis de la variación morfológica foliar en Quercus laeta Liebm. en el Parque Nacional Los Mármoles, Hidalgo, México
Zú?iga, E. á.;Sánchez-González, A.;Granados Sánchez, D.;
Revista Chapingo. Serie ciencias forestales y del ambiente , 2009,
Abstract: little is known about the species of quercus in mexico, due to its wide distribution, high intraspecific morphological variability and its capacity to form hybrids, which makes taxonomy of the genus difficult. the objective of the present study was to contribute to knowledge on foliar morphological variation of q. laeta, a widely distributed species in los mármoles national park (pnm), the second-largest natural protected area in the state of hidalgo. seventeen morphological characteristics were measured in 470 leaves collected from the lower halves of the canopies of 47 trees. all characteristics examined showed a normal distribution; a nested analysis of variance showed that the only significant morphological differences in q. laeta leaves between sites were diameter of the midvein in the central and basal portion of the leaf and petiole diameter at the base of the leaf. at the level of individuals, morphological variation was significant in 94 % of the characteristics analyzed. discriminant analysis showed that the characters that differed significantly among sites were maximum width of the leaf, distance between apical and basal sutures, distance between apical and basal lobules, leaf length, and petiole diameter. some of the foliar morphological characteristics analyzed can be considered specific to q. laeta.
Uso medicinal de las plantas por los otomíes del municipio de Nicolás Flores, Hidalgo, México
Sánchez-González, A.;Granados-Sánchez, D.;Simón-Nabor, R.;
Revista Chapingo. Serie horticultura , 2008,
Abstract: the otomies (the h??h?ü) of the nicolás flores municipality, hidalgo, have maintained their knowledge of medicinal plants over generations. allopathic medicine is limited mostly to prevention of diseases such as poliomyelitis, measles, smallpox, and malaria. it is considered that traditional medicine is more viable for this group of people because of the socioeconomic, cultural and physiographic conditions prevalent in the region. the objectives of this work were to identify the medicinal plant species used by the h??h?ü, the diseases treated with them, and their geographic affinity. for the field study, interviews were conducted with people in the municipality, and plant samples in different "ethno-ecological units" were collected. the use of 112 species was reported in treatment of disorders such as shock ("susto"), stomach pain, kidney pain, diarrhea, fever, and "mal de ojo" ("evil eye"), among others. although most of the inhabitants know the medicinal use of some plant species, the elders are the keepers of the deepest knowledge. in h??h?ü wisdom, magical-religious thought is part of their cosmovision. like other mexican ethnic groups, they consider the duality cold-hot in the treatment of diseases. the range of diseases the plants presumably heal is very broad, from colds to cancer. 75% of the species used by this ethnic group are native to the american continent, principally mexico and central america (39%), suggesting that the basic stock of traditional botanical knowledge is still observed.
Global inversion of nonsmooth mappings using pseudo-Jacobian matrices
Jesús A. Jaramillo,Oscar Madiedo,Luis Sánchez-González
Mathematics , 2013,
Abstract: We study the global inversion of a continuous nonsmooth mapping $f: \mathbb{R}^n \rightarrow \mathbb{R}^n$, which may be non-locally Lipschitz. To this end, we use the notion of pseudo-Jacobian map associated to f, introduced by Jeyakumar and Luc, and we consider a related index of regularity for f. We obtain a characterization of global inversion in terms of its index of regularity. Furthermore, we prove that the Hadamard integral condition has a natural counterpart in this setting, providing a sufficient condition for global invertibility.
Recursive Linear Estimation for Discrete-Time Systems in the Presence of Different Multiplicative Observation Noises
C. Sánchez-González,T. M. García-Mu?oz
Discrete Dynamics in Nature and Society , 2010, DOI: 10.1155/2010/875023
Abstract: This paper describes a design for a least mean square error estimator in discrete time systems where the components of the state vector, in measurement equation, are corrupted by different multiplicative noises in addition to observation noise. We show how known results can be considered a particular case of the algorithm stated in this paper. 1. Introduction It was back in 1960 when Kalman [1] introduced his well-known filter. Assuming that the dynamic system is described through a state space model, Kalman considers the problem of optimum linear recursive estimation. From this event much other research work was developed including different hypothesis frameworks about system noises [2–5]. In all studies above mentioned the estimated signal (state vector) in measurement equation is only corrupted by additive noise. Rajasekaran et al. [6] consider the problem of linear recursive estimation of stochastic signals in the presence of multiplicative noise in addition to measurement noise. When multiplicative noise is a Bernoulli random variable, the system is called system with uncertain observations. Hadidi and Schwartz [7] investigate for the existence of recursive least-squares state estimators, where uncertainty about observations is caused by a binary switching sequence which is specified by a conditional probability distribution and which enters the observation equation. The proposed solution is revisited by Wang [8], proposing new formulations for the optimal filter and the one-step predictor. The estimation problem about these systems has been extensively treated [9–11]. There have been other approaches as that of Zhang et al. [12], in which the authors consider the infinite horizon mixed H2/H∞ control for discrete-time stochastic systems with state and disturbance-dependent noise. In a very recent study [13], the optimal H2 ?ltering problems associated respectively with possible delay of one sampling period, uncertain observations and multiple packet drop-outs are studied under a uni?ed framework. In particular Sahebsara et al. [13] propose the following observation equation: where is the m-real valued measured output, is the measurement received by the estimator to be designed, and is a white binary distributed random variable with and , where and is uncorrelated with other random variables. The model introduced by Sahebsara et al. [13] describes packet drop-outs in networked estimation. The model says that the latest measurement received will be used if the current measurement is lost. Some other authors like Nakamori [14] focus their attention on
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