880 resultados para Arenas


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[EN] Meiofaunal assemblages from intertidal and shallow subtidal seabeds were studied at two sites (one dominated by volcanic sands and the other by organogenic sands) at Tenerife (Canary Islands, NE Atlantic Ocean) throughout an entire year (May 2000?April 2001). Specifically, we aimed (i) to test for differences in diversity, structure, and stability between intertidal and subtidal meiofaunal assemblages, and (ii) to determine if differences in the meiofaunal assemblage structure may be explained by environmental factors (granulometric composition, availability of organic matter, and carbonate content in sediments). A total of 103,763 meiofaunal individuals were collected, including 203 species from 19 taxonomic groups (Acari, Amphipoda, Cnidaria, Copepoda, Echinodermata, Gastrotricha, Isopoda, Insecta, Kinorrhyncha, Misidacea, Nematoda, Nemertini, Oligochaeta, Ostracoda, Polychaeta, Priapulida, Sipuncula, Tanaidacea, and Turbellaria). Nematodes were the most abundant taxonomic group. Species diversity was higher in the subtidal than in the intertidal zone at both sites, as a result of the larger dominance of a few species in the intertidal zone. The meiofaunal assemblage structure was different between tidal levels at both sites, the intertidal presenting greater temporal variability (multivariate dispersion) in the meiofaunal assemblage structure than the subtidal. Sediment grain size, here quantified by the different granulometric fractions, explained the variability in meiofaunal assemblage structure to a greater extent than the percentage of carbonates, a variable linked to sediment origin. This study revealed differences in diversity, assemblage structure, and variability between intertidal and subtidal meiofauna.

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[ES] En esta cuarta edición vamos a pasear por el entorno urbano de la ciudad de Las Palmas de Gran Canaria, donde podremos apreciar sobre qué materiales se ha construido la ciudad y cómo la actividad humana ha transformado totalmente su paisaje natural. Comenzaremos en La Puntilla hablando de La Isleta, analizando el crecimiento de este islote que posteriormente quedó unido al resto de la isla por un tómbolo de arena. Seguiremos a lo largo del Paseo de Las Canteras observando cómo varía el tipo de arenas en la playa actual, así como los distintos materiales que formaron parte de ese antiguo tómbolo de arena, los más representativos de ellos formando la barra. Finalmente, una vez hayamos descansado a comer en la Plaza de la Música, al lado del Auditorio Alfredo Kraus, iremos hacia el camino de Los Giles, en la desembocadura del Barranco de Tamaraceite, donde existen interesantes afl oramientos de la Formación Detrítica de Las Palmas que constituye el sustrato geológico principal sobre el que se asienta la ciudad alta (Figura 1). Lamentablemente no podemos seguir el camino hacia El Rincón (Mirador del Atlante) ya que se encuentra en obras, pero podremos buscar equivalencias con los materiales que allí afl oran, en lo que uno de los cortes geológicos más espectaculares que existen en Gran Canaria y que condensa casi toda su historia geológica.

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Laboratory of Coastal Biodiversity, CIMAR-Centro Interdisciplinar de Investigação Marinha e Ambiental, Porto, Portugal

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[ES]En el sur de la isla de Gran Canaria se encuentran las playas de El Inglés y Maspalomas, que comparten el Campo de Dunas de Maspalomas. El conjunto de playas-dunas forman un sistema morfodinámico de arenas ajustado a un patrón de comportamiento abierto con retroalimentaciones. Dentro de éste, se hace el seguimiento de un proceso de acreción. También, se describe el conjunto de intervenciones que ha soportado el sistema playa-dunas desde el inicio de la explotación turística. Con las actuaciones descritas, se hace una evaluación cuantitativa de impactos ambientales heredados, como parte de un diagnóstico de situación previo a la redacción de proyectos de mejora del uso turístico del marco geográfico en consideración.

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[ES] La historia geológica de los últimos cien mil años de Fuerteventura comienza con los depósitos marinos jandienses que contienen caracolas, los estrombos, que viven en la actualidad sólo en el Golfo de Guinea. Matas Blancas, en el sur de la isla, es un espectacular yacimiento de estos estrombos. Los estrombos fósiles aparecen también en toda la cuenca del Mediterráneo e indican un cambio climático de carácter muy cálido y de causas astronómicas. Posteriormente, con la llegada de los fríos de la última época glacial, fuertes vientos del Atlántico acumula­ron arenas formándose dunas y coincidiendo esto con la gran desertización del Sahara.

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[ES] Hace cinco millones de años, en los inicios de los tiempos pliocenos, el mar dejó sus arenas y gravas conteniendo multitud de conchas y caparazones de aquella época sobre la costa oeste de Fuerteventura. Hoy estos depósitos de areniscas y conglomerados están a una altura que varía entre los 10 y los 60 metros.

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CHEMICAL COMMUNICATION IN BLATTARIA: CONTRIBUTION TO THE IMPROVEMENT OF THE CONTROL TECNIQUES The management of cockroach infestations in urban environment has undergone some changes in recent years by moving to the predominant use of baits, thanks to the awareness of the risks connected with the use of spray insecticides. The effectiveness of a bait is determined by the collective performance of its components, including active and inert ingredients, the food attractant and any other attractive odour. This research has focused on the behavioral responses of Italian sinanthropic cockroaches to semiochemicals and food attractants, for the purpose of evaluating a possible practical application and of contributing to the improvement of control techniques. Behavioral and morphological studies have been carried out on Supella longipalpa (F.), a small cockroach that is spreading in Italy. Behavioral assays showed that the fourth and fifth tergites of females are significantly more attractive than other region of the body. Cuticular pores and ducts ending in glandular structures (observed with a S.E.M. = Scanning Electron Microscope) are present in large number on these tergites, suggesting that they could be involved in the production and the release of sexual pheromone. Cockroaches produce an aggregation pheromone that is excreted along with their frass and that consists of volatile and non-volatile compounds, mainly amines and steroidal glycosides. The effectiveness of faecal extracts obtained from excrements of Blattella germanica (L.), Blatta orientalis L., Periplaneta americana (L.) and S. longipalpa was evaluated, both at intraspecific and interspecific level, using a "Y" tube olfactometer. Bioassays showed that faecal extracts obtained with methanol have a good intraspecific attractiveness and, in some cases, they showed also interspecific behavioral responses. A gel was prepared, having physical characteristics that could give a good resistance to dehydration, as a potential basis for a new bait; the gel was then added faecal extracts, obtained with methanol from B. germanica and S. longipalpa frass. Arena-tests showed that the new gel containing faecal extracts is more attractive than some commercial gel formulations used as comparison: it was the only product that could attract 100% of insects placed in the arenas in 4-5 days. In conclusion, the substances involved in chemical communication of Blattaria may be able to effectively increase the attractiveness of products for monitoring and controlling cockroaches.

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[ES]La singularidad del Geoparque de Lanzarote y Archipiélago Chinijo radica en la interacción de los procesos volcánicos con procesos activos como el movimiento de las arenas o la dinámica litoral. La falta de vegetación y la excepcional conservación de los Lugares de Interés Geológico hacen de este Geoparque un lugar único para el estudio de los procesos volcánicos y la dinámica exógena en medio árido

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The thesis aims at inquiring into the issue of innovation and organizational and institutional change in the public administration with regard to the increasingly massive adoption of participatory devices and practices in various arenas of public policies. The field of reference regards transformations of the types of public actions and regulation systems, concerning governance. Together with the crisis of the public function and of the role played by the insitutions what is emerging are different levels of governement, both towards an over national and a local direction, and a plurality of social interlocutors, followed by a post-bureaucratic pattern of the public administration that is opening itself in the direction of environment and citizens. The public adminstration is no longer considered an inert object within the bureaucratic paradigm but as a series of communicative processes, choices, cultures and practices that actively builds itself and the environment it interacts with. Therefore, the output of the public administration isn’t the simple service being supplied but the relationship enacted with the citizen, relationship that becomes the constituent basis of adminstrative processes. The intention of thesis is to take into consideration the relation between innovation of the public administration and participatory experimentations and implementations regarded as exchanges in which citizens and the public administration hold talks and debates. The issue of the organizational change of the public administration as output and effect of inclusive deliberative practices has been analysed starting from an institutionalist approach, in other words examining the constituent features of institutions, “rediscovering” them with regard to their public nature, their ability to elaborate collective values and meanings, the social definition of problems and solutions. The participatory device employed by the Forlì city council that involved enterprises and cultural associations of the area in order to build a participatory Table, has been studied through a qualitative methodology (participant observation and semi-strutctured interviews). The analysis inquired into the public nature both of the participatory device and the administrative action itself as well as into elements pertaining the deliberative setting, the regulative reference framework and the actors which took part in the process.

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The research explores the mechanisms in the formation and consolidation of a new regime which combines democratic and authoritarian features; it has emerged as result of democratization processes affecting different world areas in recent years. The study analyses a case of great international significance, post-communist Russia: here internal factors strongly prevail in front of the external variables of democratic imitation and contagion, thus showing to what extent Russia differs from other political contexts. The study intends to examine the strategies used by this regime to solve internal conflicts and become stable in spite of the democratizing pressures coming from outside. Indeed, the literature about political transformations has shown the problems in analyzing these polities together with the need to examine their peculiarities more in depth. In this perspective, the first section focuses on the dynamics of State-building in Russia as a fundamental process in tracing the specific characteristics of the current regime: particularly, it is suggested that the State dimension comes out as crucial in determining the level of political and social pluralism accepted in post-Soviet Russia. This argument is worked out in the second section, which analyses the main mechanisms used by the incumbents to limit and control pluralism within the two arenas of political competition and civil society, from where the major threats to the status quo are supposed to come. The main hypothesis is that the leadership interventions in these spheres during the last ten years have shaped a regime which can be characterized as a new type of authoritarianism: with respect to traditional authoritarian forms a certain degree of political contestation is accepted, visible in the presence of a multiparty system, semi-competitive elections and of the several representatives of civil society. Yet, this diversity is curbed basically in two different ways: from one hand the incumbents provide support to political and social actors who sponsor government politics (see the party of power and pro-Kremlin movements). From the other they use some non coercive forms of control and restriction (in legislation, in political elections) against those actors who promote values and priorities opposed to the official ones.

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Il presente lavoro di ricerca si propone di discutere il contributo che l’analisi dell’evoluzione storica del pensiero politico occidentale e non occidentale riveste nel percorso intellettuale compiuto dai fondatori della teoria contemporanea dell’approccio delle capacità, fondata e sistematizzata nei suoi contorni speculativi a partire dagli anni Ottanta dal lavoro congiunto dell’economista indiano Amartya Sen e della filosofa dell’Università di Chicago Martha Nussbaum. Ci si ripropone di dare conto del radicamento filosofico-politico del lavoro intellettuale di Amartya Sen, le cui concezioni economico-politiche non hanno mai rinunciato ad una profonda sensibilità di carattere etico, così come dei principali filoni intorno ai quali si è imbastita la versione nussbaumiana dell’approccio delle capacità a partire dalla sua ascendenza filosofica classica in cui assume una particolare primazia il sistema etico-politico di Aristotele. Il pensiero politico moderno, osservato sotto il prisma della riflessione sulla filosofia della formazione che per Sen e Nussbaum rappresenta la “chiave di volta” per la fioritura delle altre capacità individuali, si organizzerà intorno a tre principali indirizzi teorici: l’emergenza dei diritti positivi e sociali, il dibattito sulla natura della consociazione nell’ambito della dottrina contrattualista e la stessa discussione sui caratteri delle politiche formative. La sensibilità che Sen e Nussbaum mostrano nei confronti dell’evoluzione del pensiero razionalista nel subcontinente che passa attraverso teorici antichi (Kautylia e Ashoka) e moderni (Gandhi e Tagore) segna il tentativo operato dai teorici dell’approccio delle capacità di contrastare concezioni politiche contemporanee fondate sul culturalismo e l’essenzialismo nell’interpretare lo sviluppo delle tradizioni culturali umane (tra esse il multiculturalismo, il comunitarismo, il neorealismo politico e la teoria dei c.d. “valori asiatici”) attraverso la presa di coscienza di un corredo valoriale incentrato intorno al ragionamento rintracciabile (ancorché in maniera sporadica e “parallela”) altresì nelle tradizioni culturali e politiche non occidentali.