3,946 research outputs found
New results on metric-locating-dominating sets of graphs
A dominating set S of a graph is a metric-locating-dominating set if each vertex of the graph is uniquely distinguished by its distanc es from the elements of S , and the minimum cardinality of such a set is called the metri c-location- domination number. In this paper, we undertake a study that, in general graphs and specific families, relates metric-locating-dominatin g sets to other special sets: resolving sets, dominating sets, locating-dominating set s and doubly resolving sets. We first characterize classes of trees according to cer tain relationships between their metric-location-domination number and thei r metric dimension and domination number. Then, we show different methods to tran sform metric- locating-dominating sets into locating-dominating sets a nd doubly resolving sets. Our methods produce new bounds on the minimum cardinalities of all those sets, some of them involving parameters that have not been related so farPostprint (published version
Estudio de los restos humanos procedentes de un hipogeo púnico en Sant Antoni de Portmany (Eivissa)
Abstract not availabl
The Geography as a Regulator of Genetic Flow and Genetic Structure in Andorra
The Principality of Andorra is one of the smallest states in Europe. Traditionally its economy has been based on the agriculture and cattle ranch although in the last decades it has developed an important tourist activity that has become a collector of emigrants. The origin of marriage consorts has been analyzed in the six parishes that have traditionally constituted the Principality. In total, there have been 10,208 marriages covering a continuous period from 1606 to 1960. From this information, two migration matrices have been constructed, one general and one intra-population. The study of the first one shows the existence of a male migration to long distance, mainly from the nearby Catalan provinces. It also shows that the main parameter that regulates migration is geography and that it indirectly defines the language’s performance and political boundaries as the genetic filters. For the study of the intrapopulation matrix, two methods have been used. On the one hand, a tree has been constructed and has been linked to Principal Component Analysis (PCA). Different matrices have also been tested by applying the Mantel test. The results indicate that there is no asymmetry in the mobility of men and women in an intra-population level, a result that is justified by the demographic and social structure of the small population centers of the Pyrenees. It is also shown that geography is the main governing factor travel within the Principality. And finally, we can observe the existence of a genetic substructure in the Andorran population marked again by geography
Síndromes dolorosos
El dolor constituye uno de los aspectos del ser humano más difíciles de definir y por lo tanto de clasificar.Según la Asociación Internacional para el Estudio del Dolor (IASP), éste se define como "experiencia sensorial y emocional desagradable asociada con una lesión tisular real o potencial, o que se describe como la ocasionada por dicha lesión". Esta definición recoge dos aspectos fundamentalespara la comprensión y clasificación de los síndromes dolorosos. Primero, califica el dolor como experiencia y no como mera sensación, reconociendo que junto al componente sensorial generado por la estimulación de las vías nerviosas (nocicepción), existe un complejo componente individual que se traduce en un conjunto de emociones que confieren al dolor un carácter único y personal. Segundo, establece que no es precisa una lesión real para que el dolor aparezca, ya que puede manifestarse en ausencia de cualquier afectación tisular. Por todo lo expuesto, cuando se considere el dolor desde el punto de vista médico, debe tenerse en cuenta la existencia de un componente sensorial y emocional, así como el hecho de que no es necesaria una lesión tisular evidenciable de forma objetiva.Además de lo anterior, los clínicos encargados de prestar atención a los pacientes con dolor, no deben olvidar que este puede estar presente a pesar de la ausencia decomunicación objetiva por parte del paciente, como sucede con los recién nacidos o los enfermos con incapacidad para comunicarse. En base a todo lo anteriormente comentado, se puede concluir que para el estudio del dolor es fundamental la correcta clasificación de los síndromes dolorosos, pudiendo realizarse desde distintas perspectivas sin quepueda definirse ninguna como superior a otra. Desde un punto de vista académico y práctico puede realizarse una división inicial del dolor en benigno y maligno; para posteriormente clasificarlo según el mecanismo etiopatogénico que lo causa en: somático, visceral y neuropático; y según su patrón temporal de aparición en agudo y crónico.A continuación se desarrollan los principales síndromes dolorosos de cada categoría. El dolor benigno es el provocado por lesiones benignas. Incluye el dolor agudo en politraumatizados, grandes quemados, postoperatorio, y en enfermedades agudas; síndromes de dolor agudo-crónico en columna vertebral, miofacial, la fibromialgia, y neuropático (neuralgia del trigémino yherpes Zóster); el dolor agudo y crónico en situaciones especiales como son el SIDA, Esclerosis Múltiple, Parkinson, Alzheimer, enfermedad cerebro vascular y en lesiones medulares; y por último en grupos especiales de pacientes como son los niños sin capacidad de hablar y en, ancianos y dementes. El maligno es el que se asocia a un cáncer progresivo. Incluye el somáticopor metástasis óseas múltiples, los síndromes vertebrales y la compresión medular; el dolor visceral pancreático y hepático; y por último el neuropático
Tumbas, parroquias y espacios ganaderos: configuración y evolución del paisaje medieval de la sierra de Ávila
In this article agricultural landscapes are conceived as the cumulative materialization of collective perceptions and forms of land-use. This perspective is applied to the historical analysis of medieval landscapes in the Sierra de Ávila, a pastoral area that offers variable and uneven information for that period. A diachronic approach using the archaeological record, written documentation, place names and palaeoenvironmental information permits tracking the contingent and ever-changing arrangements of the agroforest landscapes in this area. In early medieval times monumental tombs of large dimensions were carved out of rock by autonomous and extensive cattle farmers. These tombs are regarded as landmarks for claiming customary rights, devices that helped in the reinforcement of social cohesion and milestones for guiding flocks and shepherds. The high medieval period involved the political and legal reorganization of the rural milieu (demarcation of village territories) and a profound change of mentality (new village identities). Communal and extensive silvopastoral spaces were lost due to growing intensification of farming. The new village and parish networks anchored the peasants to their fields, thus contributing to the abandonment of the previous burial places and the implementation of parish cemeteries. In the late Middle Ages, livestock farming took on new relevance as a key strategy for aristocratic groups seeking to maximize their revenues. Community mountain pastures (or alixares) located by the early medieval necropoleis were now devoted to new land uses (dry farming and flax fields) due to their appropriation for the exclusive use of these elite groupsEste artículo aborda los paisajes agrarios como una materialización acumulativa de formas de uso y percepciones colectivas. Se aplica tal planteamiento al análisis histórico de los paisajes medievales de la sierra de Ávila, una zona de marcada vocación ganadera con muy desigual información para tal período. Una lectura diacrónica integrada del registro arqueológico, la documentación escrita, la microtoponimia y la información paleoambiental han permitido rastrear las estrategias contingentes y cambiantes que modelaron los paisajes agroforestales en la zona de estudio.
En época altomedieval unos grupos pastoriles escasamente arraigados, dedicados a la agroganadería extensiva, tallaron y usaron tumbas excavadas en roca. Además de su obvia finalidad funeraria, en este artículo se enfatiza su papel como hitos de reclamación de derechos consuetudinarios, mecanismos de cohesión social y guías de tránsito de pastores con sus rebaños por la sierra. La etapa plenomedieval supuso la reordenación económica y jurisdiccional del medio rural (deslinde de términos aldeanos, enajenación de espacios silvopastoriles comunitarios) acompañada de un profundo cambio de mentalidades (nuevas identidades aldeanas). La nueva red aldeana y parroquial, que fija el campesinado al terrazgo, supuso el abandono de los espacios sepulcrales previos y la implantación de las necrópolis parroquiales. En la Baja Edad Media, la actividad pecuaria es fomentada por los grupos aristocráticos concejiles y nobiliarios. Los pastos mancomunados serranos (alixares), donde se detectan ahora nuevos usos (cerealicultura de secano, linares), vuelven a coincidir con las antiguas necrópolis altomedievales
Standardization Framework for Sustainability from Circular Economy 4.0
The circular economy (CE) is widely known as a way to implement and achieve sustainability, mainly due to its contribution towards the separation of biological and technical nutrients under cyclic industrial metabolism. The incorporation of the principles of the CE in the links of the value chain of the various sectors of the economy strives to ensure circularity, safety, and efficiency. The framework proposed is aligned with the goals of the 2030 Agenda for Sustainable Development regarding the orientation towards the mitigation and regeneration of the metabolic rift by considering a double perspective. Firstly, it strives to conceptualize the CE as a paradigm of sustainability. Its principles are established, and its techniques and tools are organized into two frameworks oriented towards causes (cradle to cradle) and effects (life cycle assessment), and these are structured under the three pillars of sustainability, for their projection within the proposed framework. Secondly, a framework is established to facilitate the implementation of the CE with the use of standards, which constitute the requirements, tools, and indicators to control each life cycle phase, and of key enabling technologies (KETs) that add circular value 4.0 to the socio-ecological transition
An approach to visual cortex operation: optical neuron model
Several works have been published in the last years concerning the modelling and implementation of the visual cortex operation. Most of them present simple neurons with just two different responses, namely inhibitory and excitatory. Some of the different types of visual cortex cells are simulated in these configurations
Analysis of large-scale digital optical neural networks by Feynman diagrams
A new method to study large scale neural networks is presented in this paper. The basis is the use of Feynman- like diagrams. These diagrams allow the analysis of collective and cooperative phenomena with a similar methodology to the employed in the Many Body Problem. The proposed method is applied to a very simple structure composed by an string of neurons with interaction among them. It is shown that a new behavior appears at the end of the row. This behavior is different to the initial dynamics of a single cell. When a feedback is present, as in the case of the hippocampus, this situation becomes more complex with a whole set of new frequencies, different from the proper frequencies of the individual neurons. Application to an optical neural network is reported
Logic cells as basic structures to add/drop WDM information signals
Nowadays, in order to take advantage of fiber optic bandwidth, any optical communications system tends to be WDM. The way to extract a channel, characterized by a wavelength, from the optical fiber is to filter the specific wavelength. This gives the systems a low degree of freedom due to the fact of the static character of most of the employed devices. In this paper we will present a different way to extract channels from an optical fiber with WDM transmission. The employed method is based on an Optically Programmable Logic Cells (OPLC) previously published by us, for other applications as a chaotic
generator or as basic element for optical computing.
In this paper we will describe the configuration of the OPLC to be employed as a dropping device. It acts as a filter because it will extract the data carried by a concrete wavelength. It does depend, internally, on the wavelength. We will show how the intensity of the signal is able to select the chosen information from the line. It will be also demonstrated that a new idea of redundant information it is the way of selecting the concrete wavelength. As a matter of fact this idea is apparently the only way to use the OPLC as a dropping device. Moreover, based on these concepts, a similar way to route signals to different routes is reported. The basis is the use of photonic switching configurations, namely Batcher or Bayan
structures, where the unit switching cells are the above indicated OPLCs
Algunas consideraciones sobre la formación de titulados en tecnologías emergentes
Uno de los problemas más cruciales que se presenta en cualquier país cuando se pretende realizar una planificación más o menos ajustada a los objetivos que se desean alcanzar, es el de adecuar el número de profesionales en una determinada tecnología a las necesidades reales que en cada momento puedan presentarse. Este hecho, que ha llegado a tener repercusiones de carácter casi histórico en épocas pasadas, cuando se registraron saltos bruscos de un tipo de sociedad a otra, se está produciendo hoy de manera casi continua en la mayor parte de los países, tanto desarrollados como en vías de desarrollo como se verá en el presente artículo, las crisis de exceso de un tipo de profesionales en unas áreas y las de escasez de otras, está siendo un hecho habitual tanto en empresas, sean del tamaño que sean, como en entornos académicos e incluso en países y el bloques socioeconómicos como un todo
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