11 resultados para Central Poland
em Portal de Revistas Científicas Complutenses - Espanha
Resumo:
Calcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses.This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra.Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra.Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors.
Resumo:
Se ha realizado un estudio fitosociológico de la vegetación herbácea vivaz climatófila supra-oromediterránea perteneciente a la clase Koelerio-Corynephoretea en el macizo occidental de la Sierra de Gredos. Como resultado del mismo se describen las siguientes subasociaciones: Centaureo ornatae-Stipetum lagascae euphorbietosurn oxyphyllae, Arrhenathero baetici-Stipetum giganteae euphorbietosum oxyphyllae, Leucanthemopsio pallidae-Festucetum elegantis stipetosum giganteae y Thymo zygidis-Plantaginetum radicatae euphorbietosum oxyphyllae. Además se aportan datos de Leucanthemopsio pallidae-Festucetum elegantis typicum y Arenario querioidis-Festucetum summilusitanae.
Resumo:
Como inicio de una serie de notas referentes a la vegetación del Sistema Central, se propone una nueva asociación, Senecio coincyi-Trollietum europaei, incluida en Filipendulion ulmariae.
Resumo:
Se revisan fitosociológicamente los bosques y matorrales oromediterráneos del Sistema Central pertenecientes a la alianza Pino-Cytision oromediterranei. Un suborden, una asociación y seis subasociaciones se proponen como nuevos: Juniperenalia nanae, Echinosparto pulviniformis-Cytisetum oromediterranei, Cytiso-Echinospartetum barnadesii ericetsoum arboreae, Junipero-Cytisetum oromediterranei adenocarpetosum hispanici, arctostaphylletosum crassifoliae, ericetosum aragonensis, genistetosum cinerascentis y populetosum tremulae. Asimismo, se proponen diversas correcciones nomenclaturales y se tipifican los principales sintáxones de la clase. Por último, se presenta un esquema sintaxonómico de la misma en la Península Ibérica hasta el nivel de asociación, con la diagnosis biogeográfica, ecológica y florística de los sintáxones de rango superior.Finalmente, en el apéndice florístico se proponen tres nuevas combinaciones nomenclaturales: Echinospartum ibericum Rivas-Martínez, Sánchez-Mata & Sancho, E. ibericum subsp. pulviniformis (Rivas-Martínez) Rivas-Martínez y Thymus praecox Opiz subsp. penyalarensis (Pau) Rivas-Martínez, Fernández-González & Sánchez-Mata.
Resumo:
Se da a conocer la presencia del taxon Poa feratiana Boiss. & Reuter en el Sistema Central, Se comenta la corologia del taxon en la Península Ibérica.
Resumo:
Se trata en este trabajo de comentar algunas citas poco conocidas para las Sierras de Alcudia, Madrona y Puertollano en la Cordillera Mariánica.
Resumo:
Se citan algunas plantas con interés corológico herborizadas en el macizo occidental de la Sierra de Gredos.
Resumo:
The new class, the Tamaricetea arceuthoidis, is described covering riparian and intermittent shrubby vegetation of the Irano-Turanian Region in the southwestern and Central Asia and the Lower Volga valley. The dominating species are species of the genus Tamarix that refer high water table in arid and semi-arid habitats with high to moderate salinity. This new class is an ecological analogon of the Nerio-Tamaricetea occurring in the Mediterranean Basin.
Disponibilidad del recurso hídrico en la microcuenca del río Bermúdez. Región central de Costa Rica.
Resumo:
La microcuenca del río Bermúdez es parte de la principal zona de explotación hídrica en la región Central de Costa Rica, razón por la cual se realiza un diagnóstico de la disponibilidad del recurso hídrico en esta microcuenca donde se identifican las áreas con mayor problemática de disponibilidad de este recurso. Para ello se calculó un balance hídrico mensual, según uso del suelo, unidad geomorfológica y zona climática. Con base en este balance se determinó y clasificó la disponibilidad del recurso, identificando en la microcuenca solamente tres categorías: alta, media y moderada. No existen áreas de baja disponibilidad de recurso hídrico lo que demuestra que la oferta es suficiente, sin embargo, existe una presión importante sobre el recurso hídrico pues más de la mitad del área de la microcuenca se encuentra con una disponibilidad moderada.
Resumo:
This article fi rst summarizes the structural reforms of pensions (total or partial privatization) in Latin America and Central and Eastern Europe, identifying their advantages and disadvantages, and does the same with the international process of re-reforms of pensions with a greater role of the state. Second, chooses Chile as a case study, as a world pioneer in both types of reforms; describes their characteristics and effects on social welfare of the structural reform of 1981 and the re-reform of 2008. Such effects are evaluated based on ten basic principles of social security from the International Labour Offi ce (ILO): 1) social dialogue to approve the reforms, 2) universal coverage of the population, 3) equal treatment of insured persons, 4) social solidarity, 5) gender equity, 6) suffi ciency of benefi ts, 7) effi ciency and reasonable administrative cost, 8) social participation in the management of the system, 9) role of the state and supervision, and 10) fi nancial sustainability. Third, it summarizes the advantages and disadvantages-challenges of the re-reform and informs on the current debate for further reforms.
Resumo:
Historically the central area of the city of Iquique has been established as residential space migrants choosing from different backgrounds , however since the late 2000s migration flows are diversified being mostly Latin American immigrants who live in precarious conditions , accessing tugurizados properties , deteriorated in an increasingly growing informal market. The results presented here are derived from quantitative residential location of migrants , as well as the implementation of 13 in-depth interviews . From these results emerge that Latin American migrants access to the same places where once lived internal migrants, however they inhabit a restrictive market , uneven and inadequate living conditions lease, but allows them to articulate residence and proximity to industrial networks , social and popular trade.