967 resultados para Fibrosis of the subepithelial area
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All sample sites were situated at the northern tip of Napu Valley in Central Sulawesi, Indonesia. After an initial mapping of the study area, we selected 15 smallholder cacao plantations as sites for bird and bat exclosure experiments in March 2010. On each study site, we established 4 treatments for these exclosure experiments (bird exclosure - closed during daytime and open during night; bat exclosure - closed overnight and opened during daytime; full exclosure of both birds and bats - always closed and unmanipulated/open control treatments - always open). In each treatment, there were 2 cacao trees (total of 8 cacao trees per study site), surrounded by nylon filament (2x2 cm mesh size) that was opened and closed according to the activity period of day and night active flying vertebrates (05:00-06:00 am and 17:00-18:00 pm) on a daily basis. The mean tree height and diameter at breast height (dbh) result from two measures of all study trees at the beginning of the exclosure experiment (June 2010) and 6 months later (February 2011).
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This paper provides a snapshot of the permafrost thermal state in the Nordic area obtained during the International Polar Year (IPY) 2007-2009. Several intensive research campaigns were undertaken within a variety of projects in the Nordic countries to obtain this snapshot. We demonstrate for Scandinavia that both lowland permafrost in palsas and peat plateaus, and large areas of permafrost in the mountains are at temperatures close to 0°C, which makes them sensitive to climatic changes. In Svalbard and northeast Greenland, and also in the highest parts of the mountains in the rest of the Nordic area, the permafrost is somewhat colder, but still only a few degrees below the freezing point. The observations presented from the network of boreholes, more than half of which were established during the IPY, provide an important baseline to assess how future predicted climatic changes may affect the permafrost thermal state in the Nordic area. Time series of active-layer thickness and permafrost temperature conditions in the Nordic area, which are generally only 10 years in length, show generally increasing active-layer depths and rising permafrost temperatures.
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The main characteristics of the Vernagtferner mass balance are sumarized in the table below. The mass balance years from 1964/65 to 2003/2004 are listed. The table includes the total area of the glacier (basis for the calculations), the equilibrium line altitude (ELA), percentage of the accumulation area in relation to the total area (AAR) and the specific net mass balance in mm w.e. (water equivalent) per year. It becomes clear that, after a rather minor growth period in the mid 1970's, the glacier continually lost mass since the beginning of the 1980's. Besides that, a clear increase of mass balance years with extreme mass losses could be observed in the last decade. The "glacier-friendly" summer with a well-balanced mass balance in 1999 could only interrupt the series of years with extreme mass losses, but this means no change in the trend. The minor mass loss in 1999 was caused by a winter snow cover above average, which prevented the glacier from becoming snow free over large areas and thus resulted in a lower ice melt. Although real summer conditions in 2000 were mainly restricted to August and produced a snow free area only slightly larger than in 1999, there have been further ice losses. This trend of negative mass balance continued also in the years 2001 and 2002. Nevertheless, the losses are moderate because a smaller part of the glacier became ice free until autumn (appr. 50 %). The summer 2003 caused a loss of ice in a dimension never seen since the beginning of the scientific investigations. This resulted from a combination of different factors: after only a moderate winter snowcover the glacier became snow free very early. For the first time the ablation area spanned over the entire glacier (blue fields in the mass balance tables!). Only one short snowfall event interrupted the ablation period, which lasted twice as long as in the years of large losses in the 1990's. The extreme mass loss in 2003 will also influence the mass balance in the following year 2004. The graphical representation of the elevation distribution of the specific mass balance together with the absolute mass balance can be found individually for each year by choosing one of the mass balance values from the table. These diagrams also include the area-height-distribution of the glacier and the ablation area. A tabular version of the numeric values in dependence of the elevation, provided separately for the accumulation area, the ablation area and the total glacier, can be found in colums "Persistent Identifier". The tables include the results for three different parts of the glacier and for the total glacier.
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Metasediments in the three early Palaeozoic Ross orogenic terranes in northern Victoria Land and Oates Land (Antarctica) are geochemically classified as immature litharenites to wackes and moderately mature shales. Highly mature lithotypes with Chemical Index of Weathering values of >=95 are typically absent. Geochemical and Rb-Sr and Sm-Nd isotope results indicate that the turbiditic metasediments of the Cambro-Ordovician Robertson Bay Group in the eastern Robertson Bay Terrane represent a very homogeneous series lacking significant compositional variations. Major variations are only found in chemical parameters which reflect differences in degree of chemical weathering of their protoliths and in mechanical sorting of the detritus. Geochemical data, 87Sr/ 86Sr t=490 Ma ratios of 0.7120 - 0.7174, epsilonNd, t=490 Ma values of -7.6 to -10.3 and single-stage Nd-model ages of 1.7 - 1.9 Ga are indicative of an origin from a chemically evolved crustal source of on average late Palaeoproterozoic formation age. There is no evidence for significant sedimentary infill from primitive "ophiolitic" sources. Metasediments of the Middle Cambrian Molar Formation (Bowers Terrane) are compositionally strongly heterogeneous. Their major and trace element data and Sm-Nd isotope data (epsilonNd, t=500 Ma values of -14.3 to -1.2 and single-stage Nd-model ages of 1.7 - 2.1 Ga) can be explained by mixing of sedimentary input from an evolved crustal source of at least early Palaeoproterozoic formation age and from a primitive basaltic source. The chemical heterogeneity of metasediments from the Wilson Terrane is largely inherited from compositional variations of their precursor rocks as indicated by the Ni vs TiO2 diagram. Single-stage Nd-model ages of 1.6 -2.2 Ga for samples from more western inboard areas of the Wilson Terrane (epsilonNd, t=510 Ma -7.0 to -14.3) indicate a relatively high proportion of material derived from a crustal source with on average early Palaeoproterozoic formation age. Metasedimentary series in an eastern, more outboard position (epsilonNd, t=510 Ma -5.4 to -10.0; single-stage Nd model ages 1.4 - 1.9) on the contrary document stronger influence of a more primitive source with younger formation ages. The chemical and isotopic characteristics of metasediments from the Bowers and Wilson terranes can be explained by variable contributions from two contrasting sources: a cratonic continental crust similar to the Antarctic Shield exposed in Georg V Land and Terre Adélie some hundred kilometers west of the study area and a primitive basaltic source probably represented by the Cambrian island-arc of the Bowers Terrane. While the data for metasediments of the Robertson Bay Terrane are also compatible with an origin from an Antarctic-Shield-type source, there is no direct evidence from their geochemistry or isotope geochemistry for an island-arc component in these series.
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We investigated the local bird community in Central Sulawesi (Indonesia), with focus on insectivorous species in the agroforestry landscapes adjacent to the Lore Lindu National Park. All study sites were situated at the northern tip of Napu Valley in Central Sulawesi, Indonesia. After an initial mapping of the study area, we selected 15 smallholder cacao plantations as sites for our study in March 2010. These sides were mainly used for bird and bat exclosure experiments. All sited were situated along a local gradient (shade availability on each plantation) and a landscape gradient (distance to primary forest), which were independent from each other. In September 2010 and from February until June 2011, we assessed the bird community on our 15 study sites using monthly point count and mist netting sampling. Point count (20 minutes between 07 am and 10 am and in between the net checking hours) and mist netting surveys (12 hours, between 05:30 am and 17:30 pm) were conducted simultaneously but only once per month on each study site, to avoid habituation of the local bird community to our surveys. Further, point counts were conducted at least 100 m apart from the mist netting sites, to avoid potential disturbance between the two methods. We discarded all observations beyond 50 m (including those individuals that flew over the canopy) from the statistical analysis, as well as recaptures of individuals within identical mist netting rounds.
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High resolution studies from the Propeller Mound, a cold-water coral carbonate mound in the NE Atlantic, show that this mound consists of >50% carbonate justifying the name "carbonate mound". Through the last ~300,000 years approximately one third of the carbonate has been contributed by cold-water corals, namely Lophelia pertusa and Madrepora oculata. This coral bound contribution to the carbonate budget of Propeller Mound is probably accompanied by an unknown portion of sediments buffered from suspension by the corals. However, extended hiatuses in Propeller Mound sequences only allow the calculation of a net carbonate accumulation. Thus, net carbonate accumulation for the last 175 kyr accounts for only <0.3 g/cm2/kyr, which is even less than for the off-mound sediments. These data imply that Propeller Mound faces burial by hemipelagic sediments as has happened to numerous buried carbonate mounds found slightly to the north of the investigated area.
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Ground penetrating radar (GPR) and capacitive coupled resistivity (CCR) measurements were conducted in order to image subsurface structures in the Orkhon Valley, Central Mongolia. The data are extended by information from drill cores to the entire transects distinguishing different sedimentary environments in the valley. The Orkhon Valley is part of the high sensitive Steppe region in Central Mongolia, one of the most important cultural landscapes in Central Asia. There, archaeological, geoarchaeological and sedimentological research aims to reconstruct the landscape evolution and the interaction between man and environment during the last millennia since the first settlement. In May 2009 and 2010 geophysical surveys have been conducted including transects with lengths between 1.5 and 30 km crossing the entire valley and a kilometre-scaled grid in the southern part of the investigation area. The geoelectrical and GPR data revealed the existence of two layers characterized by different resistivity values and radar reflectors. The two layers do not only represent material contrasts, but also reflect the influence of sporadic permafrost which occurs in several areas of Mongolia. The results help to reconstruct the evolution of the braided Orkhon River and therefore give important hints to understand the environmental history of the Orkhon Valley.
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Shell chemistry of planktic foraminifera and the alkenone unsaturation index in 69 surface sediment samples in the tropical eastern Indian Ocean off West and South Indonesia were studied. Results were compared to modern hydrographic data in order to assess how modern environmental conditions are preserved in sedimentary record, and to determine the best possible proxies to reconstruct seasonality, thermal gradient and upper water column characteristics in this part of the world ocean. Our results imply that alkenone-derived temperatures record annual mean temperatures in the study area. However, this finding might be an artifact due to the temperature limitation of this proxy above 28°C. Combined study of shell stable oxygen isotope and Mg/Ca ratio of planktic foraminifera suggests that Globigerinoides ruber sensu stricto (s.s.), G. ruber sensu lato (s.l.), and G. sacculifer calcify within the mixed-layer between 20 m and 50 m, whereas Globigerina bulloides records mixed-layer conditions at ~50 m depth during boreal summer. Mean calcifications of Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, and Globorotalia tumida occur at the top of the thermocline during boreal summer, at ~75 m, 75-100 m, and 100 m, respectively. Shell Mg/Ca ratios of all species show a significant correlation with temperature at their apparent calcification depths and validate the application of previously published temperature calibrations, except for G. tumida that requires a regional Mg/Ca-temperature calibration (Mg/Ca = 0.41 exp (0.068*T)). We show that the difference in Mg/Ca-temperatures of the mixed-layer species and the thermocline species, particularly between G. ruber s.s. (or s.l.) and P. obliquiloculata, can be applied to track changes in the upper water column stratification. Our results provide critical tools for reconstructing past changes in the hydrography of the study area and their relation to monsoon, El Niño-Southern Oscillation, and the Indian Ocean Dipole Mode.
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Hojas Kilométricas (Kilometric Sheets). Specifically, the study focuses on those sheets referring to the city centre and surrounding area of the Royal Site of Aranjuez, a town in the south of the Province of Madrid. The aim of this study is to restore the actual size and measurements of scanned images of the Hojas Kilométricas. This would allow us, among other things, to reestablish both the format and scale of the original plans. To achieve this goal it is necessary to rectify and then georeference these images, i.e. assign them a geographic reference system. This procedure is essential in the overlaying and comparison of the Hojas Kilométricas of the Royal Site with other historical cartography as well as other sources related to the same area from different time periods. Subsequent research would allow us, for example, to reconstruct the time-evolution of the urban area, to spot new construction and to pinpoint the locations of any altered or missing buildings or architectural features. In addition, this would allow us to develop and integrate databases for GIS models applicable to the management of our cultural heritage.
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La gestión de los recursos hídricos se convierte en un reto del presente y del futuro frente a un panorama de continuo incremento de la demanda de agua debido al crecimiento de la población, el crecimiento del desarrollo económico y los posibles efectos del calentamiento global. La política hidráulica desde los años 60 en España se ha centrado en la construcción de infraestructuras que han producido graves alteraciones en el régimen natural de los ríos. Estas alteraciones han provocado y acrecentado los impactos sobre los ecosistemas fluviales y ribereños. Desde los años 90, sin embargo, ha aumentado el interés de la sociedad para conservar estos ecosistemas. El concepto de caudales ambientales consiste en un régimen de caudales que simula las características principales del régimen natural. Los caudales ambientales están diseñados para conservar la estructura y funcionalidad de los ecosistemas asociados al régimen fluvial, bajo la hipótesis de que los elementos que conforman estos ecosistemas están profundamente adaptados al régimen natural de caudales, y que cualquier alteración del régimen natural puede provocar graves daños a todo el sistema. El método ELOHA (Ecological Limits of Hydrological Alteration) tiene como finalidad identificar las componentes del régimen natural de caudales que son clave para mantener el equilibrio de los ecosistemas asociados, y estimar los límites máximos de alteración de estas componentes para garantizar su buen estado. Esta tesis presenta la aplicación del método ELOHA en la cuenca del Ebro. La cuenca del Ebro está profundamente regulada e intervenida por el hombre, y sólo las cabeceras de los principales afluentes del Ebro gozan todavía de un régimen total o cuasi natural. La tesis se estructura en seis capítulos que desarrollan las diferentes partes del método. El primer capítulo explica cómo se originó el concepto “caudales ambientales” y en qué consiste el método ELOHA. El segundo capítulo describe el área de estudio. El tercer capítulo realiza una clasificación de los regímenes naturales de la cuenca (RNC) del Ebro, basada en series de datos de caudal mínimamente alterado y usando exclusivamente parámetros hidrológicos. Se identificaron seis tipos diferentes de régimen natural: pluvial mediterráneo, nivo-pluvial, pluvial mediterréaneo con una fuerte componente del caudal base, pluvial oceánico, pluvio-nival oceánico y Mediterráneo. En el cuarto capítulo se realiza una regionalización a toda la cuenca del Ebro de los seis RNC encontrados en la cueca. Mediante parámetros climáticos y fisiográficos se extrapola la información del tipo de RNC a puntos donde no existen datos de caudal inalterado. El patrón geográfico de los tipos de régimen fluvial obtenido con la regionalización resultó ser coincidente con el patrón obtenido a través de la clasificación hidrológica. El quinto capítulo presenta la validación biológica de los procesos de clasificación anteriores: clasificación hidrológica y regionalización. La validación biológica de los tipos de regímenes fluviales es imprescindible, puesto que los diferentes tipos de régimen fluvial van a servir de unidades de gestión para favorecer el mantenimiento de los ecosistemas fluviales. Se encontraron diferencias significativas entre comunidades biológicas en cinco de los seis tipos de RNC encontrados en la cuenca. Finalmente, en el sexto capítulo se estudian las relaciones hidro-ecológicas existentes en tres de los seis tipos de régimen fluvial encontrados en la cuenca del Ebro. Mediante la construcción de curvas hidro-ecológicas a lo largo de un gradiente de alteración hidrológica, se pueden sugerir los límites de alteración hidrológica (ELOHAs) para garantizar el buen estado ecológico en cada uno de los tipos fluviales estudiados. Se establecieron ELOHAs en tres de los seis tipos de RNC de la cuenca del Ebro Esta tesis, además, pone en evidencia la falta de datos biológicos asociados a registros de caudal. Para llevar a cabo la implantación de un régimen de caudales ambientales en la cuenca, la ubicación de los puntos de muestreo biológico cercanos a estaciones de aforo es imprescindible para poder extraer relaciones causa-efecto de la gestión hidrológica sobre los ecosistemas dependientes. ABSTRACT In view of a growing freshwater demand because of population raising, improvement of economies and the potential effects of climate change, water resources management has become a challenge for present and future societies. Water policies in Spain have been focused from the 60’s on constructing hydraulic infrastructures, in order to dampen flow variability and granting water availability along the year. Consequently, natural flow regimes have been deeply altered and so the depending habitats and its ecosystems. However, an increasing acknowledgment of societies for preserving healthy freshwater ecosystems started in the 90’s and agreed that to maintain healthy freshwater ecosystems, it was necessary to set environmental flow regimes based on the natural flow variability. The Natural Flow Regime paradigm (Richter et al. 1996, Poff et al. 1997) bases on the hypothesis that freshwater ecosystems are made up by elements adapted to natural flow conditions, and any change on these conditions can provoke deep impacts on the whole system. Environmental flow regime concept consists in designing a flow regime that emulates natural flow characteristics, so that ecosystem structure, functions and services are maintained. ELOHA framework (Ecological Limits of Hydrological Alteration) aims to identify key features of the natural flow regime (NFR) that are needed to maintain and preserve healthy freshwater and riparian ecosystems. Moreover, ELOHA framework aims to quantify thresholds of alteration of these flow features according to ecological impacts. This thesis describes the application of the ELOHA framework in the Ebro River Basin. The Ebro River basin is the second largest basin in Spain and it is highly regulated for human demands. Only the Ebro headwaters tributaries still have completely unimpaired flow regime. The thesis has six chapters and the process is described step by step. The first chapter makes an introduction to the origin of the environmental flow concept and the necessity to come up. The second chapter shows a description of the study area. The third chapter develops a classification of NFRs in the basin based on natural flow data and using exclusively hydrological parameters. Six NFRs were found in the basin: continental Mediterranean-pluvial, nivo-pluvial, continental Mediterranean pluvial (with groundwater-dominated flow pattern), pluvio-oceanic, pluvio-nival-oceanic and Mediterranean. The fourth chapter develops a regionalization of the six NFR types across the basin by using climatic and physiographic variables. The geographical pattern obtained from the regionalization process was consistent with the pattern obtained with the hydrologic classification. The fifth chapter performs a biological validation of both classifications, obtained from the hydrologic classification and the posterior extrapolation. When the aim of flow classification is managing water resources according to ecosystem requirements, a validation based on biological data is compulsory. We found significant differences in reference macroinvertebrate communities between five over the six NFR types identified in the Ebro River basin. Finally, in the sixth chapter we explored the existence of significant and explicative flow alteration-ecological response relationships (FA-E curves) within NFR types in the Ebro River basin. The aim of these curves is to find out thresholds of hydrological alteration (ELOHAs), in order to preserve healthy freshwater ecosystem. We set ELOHA values in three NFR types identified in the Ebro River basin. During the development of this thesis, an inadequate biological monitoring in the Ebro River basin was identified. The design and establishment of appropriate monitoring arrangements is a critical final step in the assessment and implementation of environmental flows. Cause-effect relationships between hydrology and macroinvertebrate community condition are the principal data that sustain FA-E curves. Therefore, both data sites must be closely located, so that the effects of external factors are minimized. The scarce hydro-biological pairs of data available in the basin prevented us to apply the ELOHA method at all NFR types.
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Users in the Mediterranean region face significant water supply risks. Water markets mechanisms can provide flexibility to water systems run in tight situations. The largest water infrastructure in the Iberian Peninsula connects the Segura and Tagus Basins. Stakeholders and politicians in the Tagus Basin have asked that water transfers between the two basins be eventually phased out. The need to increase the statutory minimum environmental flow in the middle Tagus and to meet new urban demands is going to result in a redefinition of the Transfer?s management rules, leading to a reduction in the transferable volumes. To minimise the consequences of such restrictions to irrigators in the Segura Basin who depend on the transferred volumes, we propose the establishment of water option contracts between both basins that represents an institutional innovation with respect to previous inter-basin spot market experiences. Based on the draft of the new Tagus Basin Plan, we propose both a modification of the Transfer?s management rule and an innovative inter-basin option contract. The main goal of the paper is to define this contract and evaluate it with respect to non-market scenarios. We also assess the resulting impact on environmental flows in the Tagus River and water availability for users in the Segura Basin, together with the economic impacts of such contract on both basins. Our results show that the proposed option contract would reduce the impact of a change in the transfer?s management rule, and reduce the supply risks of the recipient area.
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Proper understanding of processes underlying visual perception requires information on the activation order of distinct brain areas. We measured dynamics of cortical signals with magnetoencephalography while human subjects viewed stimuli at four visual quadrants. The signals were analyzed with minimum current estimates at the individual and group level. Activation emerged 55–70 ms after stimulus onset both in the primary posterior visual areas and in the anteromedial part of the cuneus. Other cortical areas were active after this initial dual activation. Comparison of data between species suggests that the anteromedial cuneus either comprises a homologue of the monkey area V6 or is an area unique to humans. Our results show that visual stimuli activate two cortical areas right from the beginning of the cortical response. The anteromedial cuneus has the temporal position needed to interact with the primary visual cortex V1 and thereby to modify information transferred via V1 to extrastriate cortices.