Search results for "Planeta"
showing 10 items of 5577 documents
Identification Techniques I
2012
Infrared (IR) and Raman spectroscopy have a high potential for characterisation of material. Extensive series of wet chemical analysis may be substituted by a single spectroscopic measurement followed by detailed chemometric data evaluation. Topics of this chapter are: (i) basics of IR and Raman spectroscopy, (ii) the registration of “correct” spectra, and (iii) spectra evaluation. Dedicated applications in the area of conservation science are collected in separate chapters. The infrared (IR) spectrum is often called the fingerprint of a substance. An IR spectrum identifies a substance like a human fingerprint. Due to their origin the features of an IR spectrum are bands, not peaks. They in…
Competencia digital ciudadana: análisis de tendencias en el ámbito educativo
2021
La competencia digital ciudadana se ha ido integrando en los procesos formativos de manera desigual, a pesar de la existencia de marcos internacionales que promueven su inclusión en los diferentes sistemas educativos. Este estudio trata de aproximarse al fenómeno desde una perspectiva bibliométrica y bibliográfica. Por un lado, se explora la producción científica en términos cuantitativos, a partir del análisis de los 87 artículos seleccionados de las bases de datos Scopus y Web of Science, analizando cuestiones como el número de autores o de citas. Por otro lado, se analiza el contenido de las 47 publicaciones disponibles en abierto, abordando cuestiones como la etapa educativa, los partic…
FLEX End-to-End Mission Performance Simulator
2016
The FLuorescence EXplorer (FLEX) mission, selected as the European Space Agency's eighth Earth Explorer, aims to globally measure the sun-induced-chlorophyll-fluorescence spectral emission from terrestrial vegetation. In the frame of the FLEX mission, several industrial and scientific studies have analyzed the instrument design, image processing algorithms, or modeling aspects. At the same time, a common tool is needed to address the overall FLEX mission performance by combining all these features. For this reason, an end-to-end mission performance simulator has been developed for the FLEX mission (FLEX-E). This paper describes the FLEX-E software design, which combines the generation of co…
Atmospheric water vapor content over land surfaces derived from the AVHRR data: application to the Iberian Peninsula
1999
A study has been carried out using simulated NOAA/advanced very high resolution radiometer (AVHRR) data at 11 and 12 /spl mu/m (with LOWTRAN-7, MODTRAN 2.0, and the TIGR database), AVHRR images of the Iberian Peninsula and the Palma de Mallorca Island, radiosonde observations at seven meteorological stations, and the AVISO database provided by Meteo France to describe, compare, and analyze two different approaches for estimating the total atmospheric water vapor content (W) over land surfaces from AVHRR data. These two techniques are: 1) the split-window covariance-variance ratio (SWCVR), based on a quadratic relationship between W and the ratio of the spatial covariance and variance of bri…
Opportunities for research on evaluation of seaport performance: A systemic analysis from international literature
2015
The purpose of this article is to analyze the opportunities for research on the theme evaluation of seaport performance through the investigation of a bibliographic portfolio of articles with scientific relevance. In order to reach this goal, the intervention tool used was ProKnow-C (Knowledge Development Process – Constructivist), which consists of a structured process for the generation of knowledge on a determined theme from the interests and limitations of the researcher, following a constructivist view and requiring a constant interaction between the researcher and the object of his research. The highlighted results are the identification of the main characteristics of the scientific …
COMMUTING PATTERNS IN RIGA AGGLOMERATION: EVIDENCE FROM A SURVEY ANALYSIS OF YOUTH
2021
In the last ten years the evident changes of settlement patterns through suburban growth near to capital city of Latvia occurred. Increase of distance between home and routine activity places as well as changes of public transport and rapid increase of car ownership initiated significant changes in commuting patterns of inhabitants living outside of Riga. Although the commuting from suburban area to Riga is recently broadly studied, however these researches focused primarily on able-bodied population leaving behind school-age children and young people. The aim of this study is to analyse commuting patterns of young people aged 12 to 17 moving from outskirts of Riga to school located in Riga…
Estimating the contribution of organic acids to northern hemispheric continental organic aerosol
2015
Using chemical ionization mass spectrometry to detect particle-phase acids (acid-CIMS) and aerosol mass spectrometry (AMS) measurements from Colorado, USA, and two studies in Hyytiala, Finland, we quantify the fraction of organic aerosol (OA) mass that is composed of molecules with acid functional groups (facid). Molecules containing one or more carboxylic acid functionality contributed approximately 29% (45-51%) of the OA mass in Colorado (Finland). Organic acid mass concentration correlates well with AMS m/z 44 (primarily CO2+), a commonly used marker for highly oxidized aerosol. Using the average empirical relationship between AMS m/z 44 and organic acids in these three studies, together…
XMM-Newton observation of the classical T Tauri star SU Aurigae and the surrounding field
2007
Aims. We investigate the properties of the X-ray emitting plasma of the classical T Tauri star SU Aurigae and of other sources in the field of view. Methods. We use XMM-Newton to obtain a high-resolution RGS spectrum of SU Aur as well as EPIC imaging data and lowresolution spectra of the star and of other X-ray sources in the surrounding field. We reconstruct the emission measure distribution of SU Aur from the RGS spectrum using a line-based method, and we perform multi-temperature fits of the MOS spectra of the strongest sources both for the full observation and for selected time intervals to study their spectral variability. Results. The emission from SU Aur is highly variable, showing t…
The N Variscan margin of the Ruhr coal district (Western Germany): structural style of a buried thrust front?
1988
The Ruhr coal district represents part of an external fold and thrust belt of the Variscan orogen in central Europe. Extensive mining exposed molasse-type, coal-bearing clastic sequences of Upper Carboniferous age, deformed by folding and thrusting. Thrusts range in scale from decameters to 40 kilometers along strike but displacements are below 2.5 km. They are distributed in various stratigraphic levels and no regional detachment horizon is exposed. Displacement is mainly towards NW (towards the foreland) but also towards SE. The thrusts are bound to stockwerk-tectonics and die out towards depth frequently antithetic to the exposed strata. Folds vary in wavelength from decameters to more t…
Brachiopodes et Mollusques Bivalves: Concurrence ou indifférence?
1992
Resume Dans le debat entre les tenants d'une concurrence directe entre les Brachiopodes et les Mollusques Bivalves, et ceux pour lesquels la substitution des Bivalves aux Brachiopodes dans les communautes benthiques a partir du Mesozoique n'est que la consequence de potentialites evolutives differentes, nous proposons une analyse critique et objective des donnees disponibles et de leur interpretation. L'etude quantitative des informations (celles du Treatise) associees a l'analyse des donnees ecologiques nous conduisent a opter en faveur d'une indifference globale des deux groupes dans leurs processus evolutifs respectifs; ces processus ont ete acceleres et/ou gravement perturbes lors des g…