Search results for "Planetary Science"
showing 10 items of 4367 documents
Global health burden of PM2.5, black and organic carbon aerosols
2021
Paléoenvironnements et caractérisation des roches mères pétrolières des séries pré-salifères du bassin intérieur du Gabon
2003
Resume Le bassin interieur du Gabon, dont l'histoire est liee a la separation des continents Sud-Americain et Africain, comprend des depots continentaux fluvio-lacustres, localement glaciaires, dates du Precambrien superieur a l'Aptien p.p., surmontes par des facies marins aptiens et albiens. L'analyse par pyrolyse Rock–Eval d'echantillons d'affleurements et de forages preleves dans ce bassin met en evidence la presence de facies siliciclastiques riches en matiere organique (jusqu'a 25 % de carbone organique total) de types I et II. Ces niveaux, qui se rencontrent dans le Permien, le Neocomien-Barremien ainsi que dans l'Aptien, constituent d'excellentes roches meres et sont a l'origine des …
2020
Western Central European Loess-Palaeosol-Sequences (LPS) provide valuable terrestrial records of palaeoenvironmental conditions, which formed in response to variability in the North Atlantic climate systems. Over the last full glacial cycle (~130 ka), climate oscillations within these systems are best documented in deep sea and ice cores; the responses of terrestrial systems are not yet fully understood. A better understanding of metabolism governing input and output variables of organic- and inorganic C pools is, however, crucial for investigating landscape-atmospheric feedback processes and in particularly, for understanding the formation of calcareous LPS as environmental archives. Here …
Origin and distribution of suspended organic matter as inferred from carbon isotope composition in a Mediterranean semi-enclosed marine system
1999
The origin and distribution of suspended organic matter, the trophic features and the stable carbon isotopic composition of particulate organic carbon (POC) were studied monthly in a Western Mediterranean semi-enclosed basin. Sampling stations were selected as a function of wind-exposure and the degree of vegetation cover and then compared with an adjacent unvegetated site. The predominant vegetation was seagrass (Posidonia oceanica and Cymodocea nodosa) and Caulerpa prolifera. Water samples were analyzed for total suspended matter (inorganic and organic fractions), photosynthetic pigments (chlorophyll-a and phaeopigments), dissolved organic carbon, particulate organic carbon and their isot…
In-situ reflectance spectroscopy - analysing techniques for high-resolution pigment logging in sediment cores
2003
The temporal resolution of marine proxy data is limited by analytically required sample size. We present in-situ reflectance spectroscopy techniques (usually applied in remote sensing) to analyse the organic fraction of marine and terrestrial sediment. From absorption band depths, photosynthesis pigment variations are derived for sediments from the upwelling region off Peru, where productivity is related to the annual variability of El Nino strength. Quantitative estimations of diagenetic photosynthesis pigments derived from absorption band analysis in reflectance spectra are highly correlated to organic carbon content. The ratio of pigment fractions is related to chlorine concentration and…
Propuesta de un método de evaluación del patrimonio cultural y su aplicación en Cortes de Pallás (Valencia)
2020
Las áreas rurales han experimentado significativas transformaciones socioeconómicas en las últimas décadas, en las cuales ha sido común la competencia de los ámbitos urbanos. Actualmente constituyen espacios multifuncionales caracterizados por el desempeño de nuevas actividades, donde el patrimonio se configura como un recurso esencial en las estrategias de desarrollo territorial (local). No obstante, el diseño de proyectos de valorización requiere la identificación del valor de cada bien. El propósito del estudio es la propuesta de un método de evaluación del patrimonio cultural, conformado por tres sistemas específicos que permiten cuantificar el interés patrimonial de los bienes inmueble…
Quantitative structural analysis of trabecular alveolar bone in the mandible by multidetector computed tomography: Differences according to tooth pre…
2019
Background and objective: There is a lack of quantitative measures of the quality of alveolar trabecular bone, an important factor in implantology. This study aimed to develop a method of objectively assessing the quality of trabecular bone by means of image processing and structural analysis of multidetector computed tomography images and to establish differences between tooth types and tooth presence/absence. Materials and methods: We analyzed 20 patients who underwent multidetector computed tomography to evaluate mandibular bone and tooth positioning. Image analysis included automatic segmentation of the mandible, obtainment of sections perpendicular to the dental arch, and structural an…
Comparison of metals and essential trace elements levels between Autistic Spectrum Disorders cases and their sibs in Sicily (southern Italy)
2016
Introduction: A role of metals exposure and essential trace element deficiency in Autistic Spectrum Disorders (ASD) etiology has been suggested by epidemiologic studies, but conclusive evidence on this topic is still lacking and controversial. We compared metals and essential trace element levels between cases both with their brothers and healthy children. Methods: The diagnosis of ASD were performed by ADOS and ADI-R according to DSM IV (Diagnostic and Statistical Manual of Mental Disorders) criteria. Hair samples were collected from cases and sibs by single cutting from the occipital region. The samples were cut to lengths of about 1.5–2 cm using clean stainless steel scissors. Approximat…
Trace elements and plasma metabolomics in a general population from Spain: The Hortega Study
2021
Quantitative palaeotemperature estimates based on fossil chydorid ephippia: calibration and validation of a novel method for northern lakes
2015
To fully utilize palaeolimnological archives for tracking past environmental changes, methodological advances are necessary. We present a novel method to quantitatively reconstruct past summer air temperatures based on fossil chydorid (Cladocera: Chydoridae) ephippia assemblages. We examined a 76-lake training set from Finland for chydorid ephippia distribution to develop a transfer function for summer air temperatures. Subsequently, we tested its usability in downcore reconstructions by inferring Holocene temperatures from Lake Arapisto in southern Finland. Significant climate-related variation was found in the distribution and abundance of chydorid ephippia in the training set. A transfer…