2,653 research outputs found
A generalization of Krasnosel'skii compression fixed point theorem by using star convex sets
In the framework of fixed point theory, many generalizations of the classical results
due to Krasnosel’skii are known. One of these extensions consists in relaxing the
conditions imposed on the mapping, working with k-set contractions instead of
continuous and compact maps. The aim of this work if to study in detail some fixed
point results of this type, and obtain a certain generalization by using star convex
sets.The research of C. Lois-Prados was partially supported by a grant of 'Programa de Iniciación á Investigacióon nas Ciencias Matemáticas e as súas Aplicacións' from the Vicerreitoría de Investigación e Innovación and the Instituto de Matemáticas (USC). The research of R. Rodríguez-López was partially supported by grant number MTM2016-75140-P (AEI/FEDER, UE).S
Estudio de viabilidad para la creación de una empresa dedicada a la fabricación y comercialización de bicicletas sustentables
En los parámetros de sustentabilidad se involucran todos los aspectos relacionados con las actividades del ser humano; dentro de las cuales se pretende resaltar: la movilidad, como una condición inherente al desarrollo urbano en las ciudades y de los ciudadanos, también, reconocido como sistema en el que convergen flujos de desplazamiento, medios de transporte e infraestructura vial; variables dependientes de características propias y particulares de cada ciudad, además, de los desafíos que trae consigo este concepto como: la contaminación ambiental, la congestión entre otros.
A partir del contexto de la realidad que se vive en la ciudad Pereirana desde la perspectiva de la movilidad, se encuentra la oportunidad de viabilizar una iniciativa empresarial, donde el producto estrella es una bicicleta sustentable construida con biomasa, específicamente una gramínea del género Phyllostachys especie aurea. Se escoge este tipo de Bambú por sus características físicas y mecánicas, además, porque más que ser una planta el bambú ha forjado culturas y se le atribuye el desarrollo social, económico y ambiental de regiones en todo el mundo
Effect of mold temperature on the impact behavior and morphology of injection molded foams based on polypropylene polyethylene–octene copolymer blends
Producción CientíficaIn this work, an isotactic polypropylene (PP) and a polyethylene–octene copolymer (POE) have been blended and injection-molded, obtaining solids and foamed samples with a relative density of 0.76. Different mold temperature and injection temperature were used. The Izod impact strength was measured. For solids, higher mold temperature increased the impact resistance, whereas in foams, the opposite trend was observed. In order to understand the reasons of this behavior, the morphology of the elastomeric phase, the crystalline morphology and the cellular structure have been studied. The presence of the elastomer near the skin in the case of high mold temperature can explain the improvement produced with a high mold temperature in solids. For foams, aspects as the elastomer coarsening in the core of the sample or the presence of a thicker solid skin are the critical parameters that justify the improved behavior of the materials produced with a lower mold temperature.Ministerio de Economía, Industria y Competitividad (grant DI-15-07952
El TDAH y su relación con la obesidad a lo largo de la vida.
Traballo fin de grao (UDC.FEP). Enfermarí
Análisis de la legislación que regula la Distribución de los Bienes Comunales a causa del Divorcio en Nicaragua
El divorcio es un tema muy polémico puesto que tras intentar disolver el vímatrimonial existente entre los cónyuges, acarrea consigo efectos jurídicos que
afectan a terceros, por lo cual es importante realizar un estudio minucioso y exhaustivo de l
os efectos que surge a raíz de este .
Esta investigación tiene como finalidad realizar un análisis sobre los tipos de regímenes matrimoniales en la disolución del vínculo matrimonial, por lo que se
utilizó el método cualitativo, análisis, recolección de datos teóricos y prácticos a través de textos, sitios web, trabajos monográficos, expedientes logrando desarrollar tres capítulos que tratan respectivamente
sobre generalidades de la disolución del vínculo matrimonial, regímenes matrimoniales y legislación
que regula esta materia.
Siendo necesario analizar el tipo de régimen económico que los cónyuges deciden constituir, y poder encontrar de esta forma cual sería el beneficio que se obtendría de cada régimen para los esposos que decidan poner fin a su relación conyugal y por consiguiente darnos cuenta si ambos adquieren igualdad de derechos como resultado de la disolución del vínculo matrimonial.
En conclusión se considera que Nicaragua debe recoger en un sola norma todo lo relacionado a los regímenes económicos matrimoniales enfocada a garantizar una
efectiva y justa liquidación del régimen que los cónyuges hayan estipulado al celebrar capitulaciones matrimoniales antes o durante su matrimonio con la finalidad de que
exista una igualdad de derechos ante la ley una vez que se decida romper con su lazo conyugal
Myocardial trabeculation in embryos of Scyliorhinus canicula (Elasmobranchii, Chondrichthyans)
Currently, three types of ventricular myoarchitecture are recognized in vertebrates, namely compact, spongy (trabeculated) and mixed myocardium. Mixed myocardium, which has been recently proposed as the primitive condition in gnathostomes, is composed of two myocardial layers: an inner trabeculated and an outer compact one. The trabeculation process has been studied in teleosts, showing exclusively spongy myocardium, and mammals and birds, characterized by a compact myocardial ventricular wall. In zebrafish, mouse and chicken embryos, the trabeculae develop as luminal myocardial ridges protruding into the lumen. In mammals and birds, further compactation of trabeculae leads to the formation of a compact layer. The potential mechanisms that may contribute to the formation of the ridges are under discussion and include myocardial proliferation, endocardial invagination, and bending of the entire myocardial layer. However, no description of the development of the mixed myocardium is available.
To shed some light on this issue, we have studied the heart development of an elasmobranch species with mixed myocardium, the lesser spotted dogfish (Scyliorhinus canicula; Chondrichthyes), by means of histological and immunohistochemical techniques for light microscopy, semithin sections, scanning electron microscopy and transmission electron microscopy.
Our results suggest that in the dogfish the intertrabecular spaces develop by connections between early intramyocardial spaces and the lumen of the ventricle through invaginations of the endocardial line. Chondrichthyans are the earliest diverged lineage of gnathostomes and, consequently, they have the most primitive cardiac design. Although chicken, mouse, and recently zebrafish have been considered powerful vertebrate models to study heart development, we propose that the trabeculation process in the dogfish is representative of the early steps of the ventricular morphogenesis in vertebrates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Study supported by grant CGL2017-85090-P and CGL2014-52356-P (Ministerio de Economía y Competitividad), FPU15/03209 (Ministerio de Educación, Cultura y Deporte), FEDER, and Universidad de Málaga
Krasnosel'skii type compression-expansion fixed point theorem for set contractions and star convex sets
This is a post-peer-review, pre-copyedit version of an article published in Journal of Fixed Point Theory and Applications. The final authenticated version is available online at: http://dx.doi.org/10.1007/s11784-020-00799-0In this paper, we give or improve compression-expansion results for set contractions in conical domains determined by balls or star convex sets. In the compression case, we use Potter’s idea of proof, while the expansion case is reduced to the compression one by means of a change of variable. Finally, to illustrate the theory, we give an application to the initial value problem for a system of implicit first order differential equations.Cristina Lois-Prados and Rosana Rodríguez-López acknowledge the support of the research grant MTM2016-75140-P (AEI/FEDER, UE). The research of Cristina Lois-Prados has been partially supported by grant ED481A-2018/080 from Xunta de Galicia.S
Correlation Analysis of High-Throughput Fruit Phenomics and Biochemical Profiles in Native Peppers (Capsicum spp.) from the Primary Center of Diversification
[Abstract] The main goal of this work was to investigate the relationship between the fruit morphology and biochemical composition of peppers (Capsicum spp.). For that purpose, one hundred native varieties from the Andean region, where the genus Capsicum has its origin, were analysed for different phytochemical compounds. In addition, pepper fruits were assessed with the highly precise phenomics tool Tomato Analyzer. The collection showed a broad variability which was more evident within the C. annuum group. On average, C. frutescens accessions displayed the highest levels of solid soluble content, pH, polyphenols and antioxidant activity. The Tomato Analyzer descriptors under the categories of size, shape index, and latitudinal section, mostly contributed to the variance among Capsicum groups. C. annuum hold the larger fruits, whereas C. frutescens comprised fruits of smaller sizes. The correlation analysis revealed that biochemical traits were negatively correlated with the fruit parameters related to size, suggesting that huger fruits contain lower amounts of chemical metabolites. The multivariate approximations demonstrated that Andean peppers assorted according to morphometric and colorimetric characteristics, but independently of their species or geographical origin. Groups of valuable native varieties carrying promising traits were identified.Ministerio de Economía y Competitividad; RTA2015-00042-C02-02Xunta de Galicia; ED431C 2018/57This research was funded by Spanish Institute for Agricultural and Food Research and Technology (INIA), co–financed by the European Regional Development Fund (FEDER) (Project RTA2015-00042-C02-02), and by Xunta de Galicia (Project ED431C 2018/57
The bulbus arteriosus of the holocephalan heart
El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-074.Previous work has shown that the outflow tract of the elasmobranch heart, namely the
cardiac portion intercalated between the ventricle and the ventral aorta, does not consist
of a single component, the conus arteriosus, as has classically been assumed, but two,
the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. From the
evolutionary perspective, knowledge of the anatomy of the cardiac outflow tract of the
holocephali is important, as they are the sister group of elasmobranchs. Our aim is to
describe the cardiac outflow tract of four holocephalan species, two of them, Chimaera
monstrosa and Hydrolagus affinis of the family Chimaeridae, and the other two, Harriotta
raleighana and Rhinochimaera atlantica, of the family Rhinochimaeridae. The cardiac
outflow tract of the four species consisted of a myocardial conus arteriosus, furnished
with valves, and a bulbus arteriosus devoid of cardiac muscle. Both the bulbus and
conus are tubular in shape. The length of the bulbus relative to the total length of the
outflow tract is somewhat smaller in the rhinochimaerids (15%-19%) than in the
chimaerids (19%-23%). The bulbus is covered by epicardium and is crossed by the main
coronary artery trunks. Histologically, the bulbus is mainly composed of elastin and
collagen, and, to a lesser extent, by smooth muscle. This suggests that in
holocephalans, the bulbus actively helps to protect the gill vasculature from exposure to
high-pressure pulses of blood. Our results prove that the bulbus arteriosus is common to
chondrichthyans. In addition, they support the hypothesis that the cardiac outflow tract
consisted of a conus arteriosus and a bulbus arteriosus from the beginning of the jawed
vertebrate radiation, contributing to our understanding of the morphological changes that
have occurred at the arterial pole of the heart in both actinopterygians and
sarcopterygians.Proyecto CGL2010-16417/BOS; Fondos FEDE
MYOCARDIAL STRUCTURE AND VASCULARIZATION OF THE HEART VENTRICLE IN HOLOCEPHALI: IMPLICATIONS FOR HEART EVOLUTION
El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013. Anatomical Record, Volume 296, Special Feature — 1: P-075.It has been classically assumed that the ventricle of the primitive vertebrate heart is
composed of spongy myocardium, supplied exclusively by oxygen-poor, luminal blood.
This idea is on two facts: (1) extant agnathans have a spongy ventricular myocardium,
and (2) in avian and mammalian embryos, the formation of trabeculated myocardium
precedes the appearance of compact myocardium. Recently, it has been proposed that,
like elasmobranchs, the early gnathostomes possess a fully vascularised ventricle
composed of mixed myocardium. We tested this idea by studying the structure and
vascularisation of the ventricular myocardium in four holocephalan species of the
families Chimaeridae and Rhinochimaeridae. Chimaera monstrosa, Hidrolagus affinis
and Harriotta raleighana have a spongy myocardium covered by a thin layer of cardiac
muscle. In H. raleighana, the compacta is reduced to an extremely fine rim. In all three
species there is a well-developed coronary artery system consisting of subepicardial
vessels which give off branches that penetrate the myocardial trabeculae.
Rhinochimaera atlantica has no compacta and its ventricular coronary artery system is
reduced to subepicardial vessels that do not enter the spongy layer. This report is the
first to show that in wild living vertebrates, a coronary artery system supplying the whole
myocardium exists in the absence of a well-developed compacta, which supports
experimental work that shows that myocardial cell proliferation and coronary vascular
growth rely on genetically separated programs. We conclude that the mixed ventricular
myocardium is primitive for chondrichthyans, and that the lack of compacta in some
holocephalans is a derived character. Moreover our results support the hypotheses that
the mixed myocardium is the primitive condition in gnathostomes, and that the absence
of a compacta in different actinopterygian taxa is the result of its repeated loss during
evolution.Proyecto CGL2010-16417/BOS; Fondos FEDE
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