Search results for "adaptation"
showing 10 items of 1775 documents
El Análisis Factorial Exploratorio de los Ítems: una guía práctica, revisada y actualizada
2014
El Análisis Factorial Exploratorio es una de las técnicas más usadas en el desarrollo, validación y adaptación de instrumentos de medida psicológicos. Su uso se extendió durante los años 60 y ha ido creciendo de forma exponencial al ritmo que el avance de la informática ha permitido. Los criterios empleados en su uso, como es natural, también han evolucionado. Pero los investigadores interesados en asuntos sustantivos que utilizan rutinariamente esta técnica permanecen en muchos casos ignorantes de todo ello. En las últimas décadas numerosos trabajos han denunciado esta situación. La necesidad de actualizar los criterios clásicos para incorporar aquellos más adecuados es una necesidad urgen…
Review paper: Seasonal variation as a determinant of population structure in rotifers reproducing by cyclical parthenogenesis
1998
Monogonont rotifers live in habitats that display extensively variation in both biotic and abiotic components. Much of this variation is seasonal and therefore predictable for a given pond or lake. In 1972, King proposed one physiological and two genetic models presenting alternative modes of adaptation to this temporal variation. Our purpose in the present paper is to review and evaluate how our knowledge of the seasonal structure of rotifer populations has changed in the past 25 years. Seasonal changes in clone frequencies have been reported from three studies of natural populations using electrophoretic analysis of isozymes. In one of these studies there was evidence for substantial temp…
Un nuevo suido con dientes yugales tubulidentados e hipselorrizos del Mioceno inferior de Córcoles, España
2018
[EN] Excavations at Córcoles, Guadalajara, Spain (MN 4) in October 1987, yielded a mandible and several isolated teeth of a strange suiform with tubulidentate cheek teeth, initially interpreted to be the remains of Tubulidentata. The specimens are complete enough to remove any doubt about which Order (Artiodactyla) and Superfamily (Suoidea) they belong to. They are here attributed to the Family Doliochoeridae, being related to the genera Bransatochoerus (MP 30) and Lorancahyus (MN 2) both of which have hypsorhizic cheek teeth, the latter with tubules in the teeth, but not to the fully-expressed extent seen in the fossils from Córcoles and the molars retain a distinct and large pulp cavity, …
The value of accessibility in the culturalandcreative industries Translation-driven settings
2020
The accessibility of Cultural Creative Industries(CCI) has grown exponentially in different parts of the globe and has increasingly become part of projects of significant importance in contemporary societies that rely on informational, global, and networked systems of communication, i.e., developed countries. CCI exist within public-domain areas and are stimulated by the critical rethinking of the means which can be used to support cultural development. CCI are in fact driven by structures of the knowledge-based economy, where information, originality, and creativity contribute to providing stimuli to their rise. Their emergence is the result of advances in cultural spheres and movements, a…
A broader model for C 4 photosynthesis evolution in plants inferred from the goosefoot family (Chenopodiaceae s.s.)
2012
C 4 photosynthesis is a fascinating example of parallel evolution of a complex trait involving multiple genetic, biochemical and anatomical changes. It is seen as an adaptation to deleteriously high levels of photorespiration. The current scenario for C 4 evolution inferred from grasses is that it originated subsequent to the Oligocene decline in CO 2 levels, is promoted in open habitats, acts as a pre-adaptation to drought resistance, and, once gained, is not subsequently lost. We test the generality of these hypotheses using a dated phylogeny of Amaranthaceae s.l. (including Chenopodiaceae), which includes the largest number of C 4 lineages in eudicots. The oldest chenopod C 4 lineage da…
Integration of polyamins in the cold acclimation response
2011
8 páginas, 1 figura, 3 tablas -- PAGS nros. 31-38
Biodiversity, evolution and adaptation of fungi in exstreme environments
2013
Fungi play irreplaceable roles for ecosystem functioning. They may adopt different life styles, for example saprotrophs, symbionts or parasites: some species are cosmopolitan with a wide distribution and others, thanks to they ecological plasticity, may adapt to harsh environments precluded to most of life forms. In stressing conditions, their role is even more crucial for the recycling of organic matter or favouring nutrients uptake. When the conditions become really extreme and competion is low, fungi focus on extremotollerance and evolve peculiar competences to exploit natural or xenobiotic resources in the particular constraints imposed by the environment. This paper focuses on three di…
Technical Note: Prediction Models of Airborne Sound Insulation of Multilayer Materials with Viscoelastic Thin Sheets
2008
The growing introduction of new insulation materials in building acoustics has caused an increase of the importance of the prediction tools. Appropriate simulations allow strictly necessary laboratory measurements to be identified. In this way, costs are reduced. The demands of new legislation has resulted in the appearance of various software designed to facilitate prediction. The prediction models are based on different hypotheses: adaptation of impedances, spatial behaviour of spectral components, statistical energy distribution, the Finite Element Method (FEM), etc. Each of these models and methods offer advantages and contain limitations. In this paper, different models for prediction…
Psychological State after an Acute Coronary Syndrome: Impact of Physical Limitations
2021
The aim of this study was to investigate how physical limitations after ACS influence patients’ quality of life and health perception. This was a longitudinal clinical study. We recruited 146 patients diagnosed with ACS. The patients performed a stress test (Bruce’s protocol) for the evaluation of physical limitations and were classified according to the test result: without physical limitations (more than 10 METS), with some physical limitations (7 to 9 METS), and with high physical limitations (less than 6 METS). Significant differences were found between the three groups immediately after the diagnosis of ACS and after a period of three months, regarding health perception, anxiety, depre…
Host-based divergence in populations of the pea aphid: insights from nuclear markers and the prevalence of facultative symbionts.
2003
In North America, the pea aphid Acyrthosiphon pisum encompasses ecologically and genetically distinct host races that offer an ideal biological system for studies on sympatric speciation. In addition to its obligate symbiont Buchnera, pea aphids harbour several facultative and phylogenetically distant symbionts. We explored the relationships between host races of A. pisum and their symbiotic microbiota to gain insights into the historical process of ecological specialization and symbiotic acquisition in this aphid. We used allozyme and microsatellite markers to analyse the extent of genetic differentiation between populations of A. pisum on pea, alfalfa and clover in France. In parallel, we…