Pág. 85: «Beowulf», un poema datado por sus monstruos
Descarga por URL: http://sl.ugr.es/076p
Pág. 85: «Beowulf», un poema datado por sus monstruos
Descarga por URL: http://sl.ugr.es/076p
74949 Científicos de la Universidad de Granada y del Massachusetts Institute of Technology (MIT) de Cambridge (Estados Unidos) han desarrollado un modelo teórico de interruptor atómico que permitirá diseñar placas solares más eficaces y ordenadores cuánticos más robustos. En colaboración con la University of Technology and Design de Singapur, estos investigadores han abierto así las puertas para la construcción del primer interruptor cuántico de corriente controlado por simetría, según informó ayer la Universidad de Granada.
La fabricación del dispositivo, que permitiría controlar y modificar las corrientes de energía a nivel atómico, supone todavía un reto para la comunidad científica internacional y podría servir por ejemplo para construir materiales aislantes controlados o diseñar placas solares más eficaces.
Todo ello para lograr que optimicen el transporte de energía y por tanto su rendimiento, con el uso de la simetría como herramienta básica.
El equipo de investigadores trabaja actualmente en un diseño «realista» de un interruptor cuántico de estas características, controlado por simetría, basado en átomos fríos en cavidades ópticas coherentes.
En este trabajo, los científicos han descrito cómo la simetría, uno de los conceptos más profundos y poderosos de la física teórica, permite controlar y manipular el transporte de energía en sistemas cuánticos abiertos.
Pablo Ignacio Hurtado, autor principal del trabajo, ha señalado que un sistema cuántico abierto no es más que un conjunto de átomos o moléculas en interacción, sujetos a la acción de un entorno que los perturba constantemente. A día de hoy no se puede manipular con precisión extrema estos sistemas, que constituyen «los ladrillos» con los que esperan construir los futuros ordenadores cuánticos.
73677 An international team of scientists, coordinated by a researcher from the U. of Granada, has found that seed dormancy (a property that prevents germination under non-favourable conditions) was a feature already present in the first seeds, 360 million years ago.
Seed dormancy is a phenomenon that has intrigued naturalists for decades, since it conditions the dynamics of natural vegetation and agricultural cycles. There are several types of dormancy, and some of them are modulated by environmental conditions in more subtle ways than others.
In an article published in the New Phytologist journal, these scientists have studied the evolution of dormancy in seeds using a unique data group. This included the features of dormancy in more than 14.000 species. It is the result of Carol and Jerry Baskin’s work, the co-authors of this publication, who have been studying latency since the 60s.
The analyses conducted by this team of researchers have established that dormancy is as old as seeds themselves. In other words, the oldest among all seeds already had dormancy. ‘Of all possible types of dormancy, the oldest one already featured very sophisticated adjustments to environmental conditions», according to the coordinator of this project, Rafael Rubio de Casas, a researcher from the Environment Department at the University of Granada, and the only Spaniard involved in this research.
Producing new species
The results of this project indicate that plants without dormancy tend to be less capable of diversification, i.e. to produce new species. «This can be due to the fact that dormancy facilitates that germination only takes place at the optimal moment, in spite of changes in the environment, due either to weather phenomena, or whether due to the fact that the seeds reach a new location after dispersal. This adjustment of the plant cycle to the new environment can reduce the probability of a particular species to become extinct», Rubio de Casas pointed out.
Dormancy does not simply involve that seeds do not germinate when it is too hot or too cold, since under those conditions it is the environment itself which precludes germination. «What dormancy does is make sure that the seeds do not germinate even when conditions are favourable, which precludes germination after a summer storm, or during a few warm days in winter», the U. of Granada researcher added.
However, not all plants have dormant seeds. Actually, many species of plants simply germinate at the moment when their seeds are exposed to favourable conditions. Besides, it appears that plants can acquire and lose the dormancy of their seeds in a relatively fast way as a result of natural selection.
«For instance, in the case of cultivated plants, dormancy is one of the first features that appear to have been lost over the domestication process, and for this reason the date for sowing is such an important parameter in farming», according to Rubio de Casas.
73677 An international team of scientists, coordinated by a researcher from the U. of Granada, has found that seed dormancy (a property that prevents germination under non-favourable conditions) was a feature already present in the first seeds, 360 million years ago.
Seed dormancy is a phenomenon that has intrigued naturalists for decades, since it conditions the dynamics of natural vegetation and agricultural cycles. There are several types of dormancy, and some of them are modulated by environmental conditions in more subtle ways than others.
In an article published in the New Phytologist journal, these scientists have studied the evolution of dormancy in seeds using a unique data group. This included the features of dormancy in more than 14.000 species. It is the result of Carol and Jerry Baskin’s work, the co-authors of this publication, who have been studying latency since the 60s.
The analyses conducted by this team of researchers have established that dormancy is as old as seeds themselves. In other words, the oldest among all seeds already had dormancy. ‘Of all possible types of dormancy, the oldest one already featured very sophisticated adjustments to environmental conditions», according to the coordinator of this project, Rafael Rubio de Casas, a researcher from the Environment Department at the University of Granada, and the only Spaniard involved in this research.
Producing new species
The results of this project indicate that plants without dormancy tend to be less capable of diversification, i.e. to produce new species. «This can be due to the fact that dormancy facilitates that germination only takes place at the optimal moment, in spite of changes in the environment, due either to weather phenomena, or whether due to the fact that the seeds reach a new location after dispersal. This adjustment of the plant cycle to the new environment can reduce the probability of a particular species to become extinct», Rubio de Casas pointed out.
Dormancy does not simply involve that seeds do not germinate when it is too hot or too cold, since under those conditions it is the environment itself which precludes germination. «What dormancy does is make sure that the seeds do not germinate even when conditions are favourable, which precludes germination after a summer storm, or during a few warm days in winter», the U. of Granada researcher added.
However, not all plants have dormant seeds. Actually, many species of plants simply germinate at the moment when their seeds are exposed to favourable conditions. Besides, it appears that plants can acquire and lose the dormancy of their seeds in a relatively fast way as a result of natural selection.
«For instance, in the case of cultivated plants, dormancy is one of the first features that appear to have been lost over the domestication process, and for this reason the date for sowing is such an important parameter in farming», according to Rubio de Casas.
Los estudiantes de grado de la UGR podrán solicitar más de 4700 plazas de movilidad internacional en 57 países
El plazo finaliza el 8 de diciembre. Los estudiantes podrán formalizar su solicitud a través de un procedimiento on-line