oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 133 )

2018 ( 872 )

2017 ( 857 )

2016 ( 1158 )

Custom range...

Search Results: 1 - 10 of 428795 matches for " Juan M. Pech-Canche "
All listed articles are free for downloading (OA Articles)
Page 1 /428795
Display every page Item
Complementarity and efficiency of bat capture methods in a lowland tropical dry forest of Yucatán, Mexico Complementariedad y eficiencia de métodos de captura de murciélagos en una selva baja caducifolia de Yucatán, México
Juan M. Pech-Canche,Erendira Estrella,Diana L. López-Castillo,Silvia F. Hernández-Betancourt
Revista mexicana de biodiversidad , 2011,
Abstract: The combined use of different methods for surveying bat assemblages has increased over the last few decades. The objective of this study was to assess the efficiency of bat inventories by comparing assemblages parameters (species richness, abundance and composition) using the 3 most conventional capture methods (ground-level and sub-canopy mist nets and harp traps), in a lowland tropical dry forest in Yucatán, Mexico. In ground mist nets, only phyllostomid species were recorded, principally frugivorous and nectarivorous species, while in harp traps the majority were insectivorous species from other families. Our results indicate that for the order Chiroptera the most efficient combination of capture methods is the simultaneous use of ground mist nets and harp traps. However, an inventory of Phyllostomidae is reliably achieved with only ground mist nets. Also, a combination of ground and sub-canopy mist nets does not provide an efficient sampling strategy. El uso combinado de diferentes métodos de muestreo de ensambles de murciélagos se ha incrementado en las últimas décadas. El objetivo de este estudio fue evaluar la eficiencia de los inventarios de murciélagos comparando los parámetros del ensamble (riqueza de especies, abundancia y composición) usando los 3 métodos de captura convencionales (redes de niebla a nivel de sotobosque y sub-dosel, y trampas arpa), en una selva baja caducifolia de Yucatán, México. En las redes de sotobosque se registraron solamente especies de filostómidos, principalmente especies frugívoras y nectarívoras; mientras que en las trampas arpa, la mayoría fueron especies insectívoras de otras familias. Nuestros resultados indican que para el orden Chiroptera la combinación más eficiente de métodos de captura es el uso simultáneo de redes de sotobosque y trampas arpa. Sin embargo, se alcanza un inventario confiable de filostómidos sólo con las redes de sotobosque. Además, una combinación de redes de sotobosque y sub-dosel no provee una eficiente estrategia de muestreo.
Complementarity and efficiency of bat capture methods in a lowland tropical dry forest of Yucatán, Mexico
Pech-Canche, Juan M.;Estrella, Erendira;López-Castillo, Diana L.;Hernández-Betancourt, Silvia F.;Moreno, Claudia E.;
Revista mexicana de biodiversidad , 2011,
Abstract: the combined use of different methods for surveying bat assemblages has increased over the last few decades. the objective of this study was to assess the efficiency of bat inventories by comparing assemblages parameters (species richness, abundance and composition) using the 3 most conventional capture methods (ground-level and sub-canopy mist nets and harp traps), in a lowland tropical dry forest in yucatán, mexico. in ground mist nets, only phyllostomid species were recorded, principally frugivorous and nectarivorous species, while in harp traps the majority were insectivorous species from other families. our results indicate that for the order chiroptera the most efficient combination of capture methods is the simultaneous use of ground mist nets and harp traps. however, an inventory of phyllostomidae is reliably achieved with only ground mist nets. also, a combination of ground and sub-canopy mist nets does not provide an efficient sampling strategy.
Del texto al sexo: Judith Butler y la performatividad
Juan Enrique Pechín
Mora (Buenos Aires) , 2009,
Abstract:
Capture efficiency measurement of pollutants over a workbench with the reinforced slot exhaust system
Pech O.,Pavelek M.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134501072
Abstract: The paper deals with the measurement of the capture efficiency of pollutants by the slot reinforced exhaust system situated in two positions over the workbench. The slot reinforced exhaust system, which is known as REEXS, is the traditional slot exhaust hood equipped with an air supply inlet that intensifies exhausting along the axis of the exhaust hood. It can operate in traditional or reinforced exhaust modes. Measurements were made for the same air velocity in the suction slot and with the different momentum flux ratio of supplied and exhausted air flow. The tracer gas method was used for the capture efficiency measurement of the system. As the tracer gas the carbon dioxide was chosen. The knowledge of the shape and range of the effective exhaust area for various configurations in front of the exhaust hood is important for the exhaust hood setting according to a source of pollutants.
Infección por el Virus del Papiloma Humano en mujeres recluidas en Centros de Readaptación Social en el sureste de México
Canche,J.R.; Canul,J.; Suárez,R.; de Anda,R.; González,M.R.;
Revista Espa?ola de Sanidad Penitenciaria , 2011, DOI: 10.4321/S1575-06202011000300003
Abstract: introduction: the aim of this work is describe the epidemiology of hvp amongst female inmates. material and methods: a total of 82 women were studied in a cross sectional study. epidemiological data were collected through a direct interview. samples of cervical cells were taken. hpv and genotypes were identified by molecular test. results: global hpv prevalence was 20.7%. fifteen different genotypes were identified 60% low risk hpv, 26.7% high risk hpv and 13.3% were not classified in any of the two groups. types 6/11were the most common. 23.5% (04/17) of hpv positives samples had multiple infections, 3 with 2 genotypes and one with 3. association between infection with hpv and smoking was found, p= 0.0258, or 3.79 ic 95% (1.01-15.58).
Towards a Ryll-Nardzewski-type Theorem for weakly oligomorphic structures
Christian Pech,Maja Pech
Mathematics , 2013,
Abstract: A structure is called weakly oligomorphic if it realizes only finitely many n-ary positive existential types for every n. The goal of this paper is to show that the notions of homomorphism-homogeneity, and weak oligomorphy are not only completely analogous to the classical notions of ultrahomogeneity and oligomorphy, but are actually closely related. A first result is a Fra\"iss\'e-type theorem for homomorphism-homogeneous relational structures. Further we show that every weakly oligomorphic homomorphism-homogeneous structure contains (up to isomorphism) a unique homogeneous, homomorphism-homogeneous core, to which it is homomorphism-equivalent. As a consequence, we obtain that every countable weakly oligomorphic structure is homomorphism-equivalent with a finite or \omega-categorical structure. Another result is the characterization of positive existential theories of weakly oligomorphic structures as the positive existential parts of \omega-categorical theories. Finally, we show, that the countable models of countable weakly oligomorphic structures are mutually homomorphism-equivalent (we call first order theories with this property weakly \omega-categorical). These results are in analogy with part of the Engeler-Ryll-Nardzewski-Svenonius-theorem.
Universal homomorphisms, universal structures, and the polymorphism clones of homogeneous structures
Christian Pech,Maja Pech
Mathematics , 2013,
Abstract: Using a categorial version of Fra\"iss\'e's theorem due to Droste and G\"obel, we derive a criterion for a comma-category to have universal homogeneous objects. As a first application we give new existence result for universal structures and for \omega-categorical universal structures. As a second application we characterize the retracts of a large class of homogeneous structures, extending previous results by Bonato, Deli\'c, Dolinka, and Kubi\'s. As a third application we show for a large class of homogeneous structures that their polymorphism clone is generated by polymorphisms of bounded arity, generalizing a classical result by Sierpi\'nski that the clone of all functions on a given set is generated by its binary part. Further we study the cofinality and the Bergman property for clones and we give sufficient conditions on a homogeneous structure to have a polymorphism clone that has uncountable cofinality and the Bergman property.
On automatic homeomorphicity for transformation monoids
Christian Pech,Maja Pech
Mathematics , 2014,
Abstract: Transformation monoids carry a canonical topology --- the topology of point-wise convergence. A closed transformation monoid $\mathfrak{M}$ is said to have automatic homeomorphicity with respect to a class $\mathcal{K}$ of structures, if every monoid-isomorphism of $\mathfrak{M}$ to the endomorphism monoid of a member of $\mathcal{K}$ is automatically a homeomorphism. In this paper we show automatic homeomorphicity-properties for the monoid of non-decreasing functions on the rationals, the monoid of non-expansive functions on the Urysohn space and the endomorphism-monoid of the countable universal homogeneous poset.
Polymorphism clones of homogeneous structures (Universal homogeneous polymorphisms and automatic homeomorphicity)
Christian Pech,Maja Pech
Mathematics , 2015,
Abstract: Every clone of functions comes naturally equipped with a topology---the topology of pointwise convergence. A clone $\mathfrak{C}$ is said to have automatic homeomorphicity with respect to a class $\mathcal{C}$ of clones, if every clone-isomorphism of $\mathfrak{C}$ to a member of $\mathcal{C}$ is already a homeomorphism (with respect to the topology of pointwise convergence). In this paper we study automatic homeomorphicity-properties for polymorphism clones of countable homogeneous relational structures. To this end we introduce and utilize universal homogeneous polymorphisms. Our results extend and generalize previous results by Bodirsky, Pinsker, and Pongr\'acz.
Universal homogeneous constraint structures and the hom-equivalence classes of weakly oligomorphic structures
Christian Pech,Maja Pech
Mathematics , 2012,
Abstract: We derive a new sufficient condition for the existence of {\omega}-categorical universal structures in classes of relational structures with constraints, augmenting results by Cherlin, Shelah, Chi, and Hubi\v{c}ka and Ne\v{s}et\v{r}il. Using this result we show that the hom-equivalence class of any countable weakly oligomorphic structure has up to isomorphism a unique model-complete smallest and greatest element, both of which are {\omega}-categorical. As the main tool we introduce the category of constraint structures, show the existence of universal homogeneous objects, and study their automorphism groups. All constructions rest on a category-theoretic version of Fra\"iss\'e's Theorem due to Droste and G\"obel. We derive sufficient conditions for a comma category to contain a universal homogeneous object. This research is motivated by the observation that all countable models of the theory of a weakly oligomorphic structure are hom-equivalent---a result akin to (part of) the Ryll-Nardzewski Theorem.
Page 1 /428795
Display every page Item


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