531 research outputs found
Characterization and mapping of surface physical properties of Mars from CRISM multi-angular data: application to Gusev Crater and Meridiani Planum
The analysis of the surface texture from the particle (grain size, shape and
internal structure) to its organization (surface roughness) provides
information on the geological processes. CRISM multi-angular observations
(varied emission angles) allow to characterize the surface scattering behavior
which depends on the composition but also the material physical properties
(e.g., grain size, shape, internal structure, the surface roughness). After an
atmospheric correction by the Multi-angle Approach for Retrieval of the Surface
Reflectance from CRISM Observations, the surface reflectances at different
geometries are analyzed by inverting the Hapke photometric model depending on
the single scattering albedo, the 2-term phase function, the macroscopic
roughness and the 2-term opposition effects. Surface photometric maps are
created to observe the spatial variations of surface scattering properties as a
function of geological units at the CRISM spatial resolution (200m/pixel). An
application at the Mars Exploration Rover (MER) landing sites located at Gusev
Crater and Meridiani Planum where orbital and in situ observations are
available, is presented. Complementary orbital observations (e.g. CRISM
spectra, THermal EMission Imaging System, High Resolution Imaging Science
Experiment images) are used for interpreting the estimated Hapke photometric
parameters in terms of physical properties. The in situ observations are used
as ground truth to validate the interpretations. Varied scattering properties
are observed inside a CRISM observation (5x10km) suggesting that the surfaces
are controlled by local geological processes (e.g. volcanic resurfacing,
aeolian and impact processes) rather than regional or global. Consistent
results with the in situ observations are observed thus validating the approach
and the use of photometry for the characterization of Martian surface physical
properties
Mapping of the Ronda peridotite massif (Spain) from AVIRIS spectro-imaging survey: A first attempt
In both AVIRIS and ISM data, through the use of mixing models, geological boundaries of the Ronda massif are identified with respect to the surrounding rocks. We can also yield first-order vegetation maps. ISM and AVIRIS instruments give consistent results. On the basis of endmember fraction images, it is then possible to discard areas highly vegetated or not belonging to the peridotite massif. Within the remaining part of the mosaic, spectro-mixing analysis reveals spectral variations in the peridotite massif between the well-exposed areas. Spatially organized units are depicted, related to differences in the relative depth of the absorption band at 1 micron, and it may be due to a different pyroxene content. At this stage, it is worth noting that, although mineralogical variations observed in the rocks are at a sub-pixel scale for the airborne analysis, we see an emerging spatial pattern in the distribution of spectral variations across the massif which might be prevailingly related to mineralogy. Although it is known from fieldwork that the Ronda peridotite massif exhibits mineralogical variations at local scale in the content of pyroxene, and at regional scale in different mineral facies, ranging from garnet-, to spinel- to plagioclase-lherzolites, no attempt has been done yet to produce a synoptic map relating the two scales of analysis. The present work is a first attempt to reach this objective, though a lot more work is still required. In particular, for the purpose of mineralogical interpretation, it is critical to relate the airborne observation to field work and laboratory spectra of Ronda rocks already obtained, with the use of image endmembers and associated reference endmembers. Also, the pretty rough linear mixing model used here is taken as a 'black-box' process which does not necessarily apply correctly to the physical situation at the sub-pixel level. One may think of using the ground-truth observations bearing on the sub-pixel statistical characteristics (texture, structural pattern, surface distribution and vegetation contribution (grass,..)) to produce a more advanced mixing model, physically appropriate to the geologic and environmental contexts
Uso de trajetórias na rastreabilidade bovina.
O Brasil é um dos maiores produtores e exportadores de carne bovina do mundo em um mercado extremamente competitivo. As exigências sobre o controle da origem e produção de animais aumentam cada vez mais e novas soluções e alternativas devem ser exploradas para manter a produção de carne e o mercado de exportação. Neste aspecto a rastreabilidade animal torna-se importante como meio para auxiliar na garantia do registro da vida de um animal, desde seu nascimento até o seu abate e exportação, incluindo o registro da permanência em fazendas e contatos com outros animais. O projeto OTAG (Operational Management and Geo-decisional Prototype to Track and Trace Agricultural Production) prevê a utilização de dispositivos eletrônicos de georefenciamento em animais, por meio de colares eletrônicos, e o registro da movimentação animal dentro das propriedades. A partir dos dados de movimentação animal, associados a outras bases de dados, pretende-se obter uma série de informações para diversos níveis de usuários do controle sanitário. O presente trabalho apresenta o uso de trajetórias para a identificação do contatos entre animais, a partir dos dados georefenciados de movimentação animal. A base de dados de contatos entre animais viabiliza a identificação de possíveis animais que contaminaram ou podem ser contaminados a partir de uma determinada ocorrência da febre aftosa, uma das doenças que podem atingir os animais e prejudicar a produção de carne bovina.SBIAgro 2009
A DISCUSSION OF SOME ECOLOGICAL FACTORS AFFECTING COCCIDENCYRTUS MALLOI BLANCHARD (HYMENOPTERA: ENCYRTIDAE) AS A PARASITOID OF DIASPIDID SCALES UNDER GLASS IN FRANCE
A DISCUSSION OF SOME ECOLOGICAL FACTORS AFFECTING COCCIDENCYRTUS MALLOI BLANCHARD (HYMENOPTERA, ENCYRTIDAE) AS A PARASITOID OF DIASPIDID SCALES UNDER GLASS IN FRANCE. The encyrtid parasitoid Coccidencyrtus malloi Blanchard has been recorded in orchid glasshouses of south-eastern France where its diaspidid host, Diaspis boisduvalii Signoret (Hemiptera, Diaspididae), is sometimes a pest of ornamentals. In order to study its biology and potential as a biological control agent, it was cultured on a bromeliad and released into several hot temperate commercial houses. It was found to have a very restricted distribution which appeared to be determined by deep shade and very high humidities. Key words: Argentina, Boisduval scale, parasitoid development, thelytokous parthenogenesis, Diaspis bromeliae, D, coccois, Laeliocattleya, Vriesea, Aechmea, Cattleya, Citrullus, Cymbidium, Coccos, Dendrobium, Neodypsis, Hohenbergia
A STUDY OF TWO PLAGIOMERUS SPECIES (HYMENOPTERA: ENCYRTIDAE) PARASITISING DIASPIDID SCALES (COCCOIDEA) IN GLASSHOUSES IN FRANCE
A STUDY OF TWO PLAGIOMERUS SPECIES (HYMENOPTERA: ENCYRTIDAE) PARASITISING DIASPIDID SCALES (COCCOIDEA) IN GLASSHOUSES IN FRANCE. Plagiomerus diaspidis Crawford was imported from Tenerife (Canary Islands, Spain) and released experimentally as a biological control agent against Diaspis echinocacti (Bouché) (Hemiptera, Diaspididae) within a cactus glasshouse in south-eastern France but it failed to provide control, apparently due to very weak powers of dispersal. A second undescribed Plagiomerus was found in a wet tropical greenhouse in the same region of France and was thought to be a potential biocontrol agent of Diaspididae. It was found to parasitise the three Diaspis species (D. boisduvalii Signoret, D. coccois (Lichtenstein) and D. bromeliae (Kerner)) present in the greenhouse, although it failed to control them. Both parasitoid species reproduced by thelytokous parthenogenesis. Key words: development, Boisduval scale, preferred environments, USA, Mexico, Azerbaidjan, Opuntia, Strelitzia, Calanthe, palm
First results from analysis of coordinated AVIRIS, TIMS, and ISM (French) data for the Ronda (Spain) and Beni Bousera (Morocco) peridotites
Ultramafic rocks are relatively rare at the Earth's surface but constitute the vast majority of the Earth by volume. Exposures of ultramafic bodies are therefore crucial for deducing many important processes that occur in the Earth's mantle. An important science question regarding the spatial distribution, abundance, and composition of mafic minerals in ultramafic bodies that can be examined with advanced sensor data is the melting process. When a lherzolite melts, clinopyroxene (cpx) melts first and therefore variations in the modal amount of cpx remaining in the mantle are a reflection of the amount of fractional melting that has occurred. Fe goes preferentially into the melt during melting but a 20 percent batch melting (i.e. closed system) acquires less Fe relative to 20 percent fractional melting (i.e. open system). Since the strength and wavelength of diagnostic absorptions is a strong function of Fe content, it is possible to make maps of the variation in Fe:Mg ratios which can be related to the general melting process. Accurate ground-truth information about local mineralogy provides internal calibration and consistency checks. Investigations using imaging spectrometer are very complementary to field studies because advanced sensor data can provide a synoptic view of modal mineralogy and chemical composition whereas field studies focus on detailed characterization of local areas. Two excellent exposures of ultramafic lithologies are being investigated with visible to mid-infrared imaging spectrometer data: the Ronda peridotite near Ronda, Spain and the Beni Bousera ophiolitic fragment in northern Morocco. Although separated by the Alboran Sea, these bodies are thought to be related and represent fertile sub-continental mantle. The Ronda peridotite is predominantly spinel lherzolite but grades into harzburgite and shows considerable variation in major and trace element compositions. Mafic layering and dykes (i.e. olivine gabbro) are also observed. This indicates some sections of the peridotite have experienced greater degrees of partial melting. The Beni Bousera peridotite also contains mafic layers and dykes and grades into harzburgite representing similar fundamental shifts in the bulk chemistry of this ultramafic body probably related to an episode of partial melting. The specific mode of emplacement of these bodies is controversial and important for understanding the tectonic evolution of this region. Our investigations are not necessarily designed to help resolve this controversy. Rather, these exposures provide excellent and unusual examples of fertile mantle which have undergone variable degrees of partial melting
Towards a spatial decision support system for animal traceability.
This section presents the contributions of our work to the problems of bovine traceability and contact between animals using trajectory database concepts. This section describes how to delimitate problems and how to represent animal movements as trajectories. Afterwards, the algorithms for the identification of contacts between animals are presented for the calculation of contamination probabilities. In this work we define contamination algorithms for foot-and-mouth disease (FMD). FMD is a highly contagious disease that attacks all cleft-hoofed animals, mainly bovines. It occurs at all ages, regardless of sex, breed, climate, etc. The virus spreads by direct contact of animals as well as through the air, water and food.Contrato nº 43134
Recognizing Chordal-Bipartite Probe Graphs
A graph G is chordal-bipartite probe if its vertices can be partitioned into two sets P (probes) and N (non-probes) where N is a stable set and such that G can be extended to a chordal-bipartite graph by adding edges between non-probes. A bipartite graph is called chordal-bipartite if it contains no chordless cycle of length strictly greater than 5. Such probe/non-probe completion problems have been studied previously on other families of graphs, such as interval graphs and chordal graphs. In this paper, we give a characterization of chordal-bipartite probe graphs, in the case of a fixed given partition of the vertices into probes and nonprobes. Our results are obtained by solving first the more general case without assuming that N is a stable set, and then this can be applied to the more specific case. Our characterization uses an edge elimination ordering which also implies a polynomial time recognition algorithm for the class. This research was conducted in the context of a France-Israel Binational project, while the French team visited Haifa in March 2007
Precise design of environmental data warehouses
People use data warehouses to help them make decisions. For example, public policy decision-makers can improve their decisions by using this technology to analyze the environmental effects of human activity. In production systems, data warehouses provide structures for extracting the knowledge required to optimize systems. Designing data warehouses is a complex task; designers need flexible and precise methods to help them create data warehouses and adapt their analysis criteria to developments in the decision-making process. In this paper, we introduce a flexible method based on UML (Unified Modeling Language). We introduce a UML profile for building multi-dimensional models and for choosing different criteria according to analysis requirements. This profile makes it possible to specify integrity constraints in OCL (Object Constraint Language). We apply our method to the construction of an environmental system for analyzing the use of certain agricultural fertilizers. We integrate various data sources into a multi-dimensional model showing several categories of analysis, and the consistency of data can be checked with OCL constraints
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