Color texture analysis based on fractal descriptors

Color texture classification is an important step in image segmentation and recognition. The color information is especially important in textures of natural scenes, such as leaves surfaces, terrains models, etc. In this paper, we propose a novel approach based on the fractal dimension for color texture analysis. The proposed approach investigates the complexity in R, G and B color channels to characterize a texture sample. We also propose to study all channels in combination, taking into consideration the correlations between them. Both these approaches use the volumetric version of the Bouligand-Minkowski Fractal Dimension method. The results show a advantage of the proposed method over other color texture analysis methods. (C) 2011 Elsevier Ltd. All rights reserved.

Calibration and validation of an air quality finite element model around an electric power plant in Gran Canaria island

[EN]This work presents the calibration and validation of an air quality finite element model applied to the surroundings of Jinamar electric power plant in Gran Canaria island (Spain). The model involves the generation of an adaptive tetrahedral mesh, the computation of an ambient wind field, the inclusion of the plume rise effect in the wind field, and the simulation of transport and reaction of pollutants. The main advantage of the model is the treatment of complex terrains that introduces an alternative to the standard implementation of current models. In addition, it improves the computational cost through the use of unstructured meshes...

Negoziare confini: dagli stati di cose ai transiti

Negotiating boundaries: from state of affairs to matter of transit. The research deals with the everyday management of spatial uncertainty, starting with the wider historical question of terrains vagues (a French term for wastelands, dismantled areas and peripheral city voids, or interstitial spaces) and focusing later on a particular case study. The choice intended to privilege a small place (a mouth of a lagoon which crosses a beach), with ordinary features, instead of the esthetical “vague terrains”, often witnessed through artistic media or architectural reflections. This place offered the chance to explore a particular dimension of indeterminacy, mostly related with a certain kind of phenomenal instability of its limits, the hybrid character of its cultural status (neither natural, nor artificial) and its crossover position as a transitional space, between different tendencies and activities. The first theoretical part of the research develops a semiotic of vagueness, by taking under exam the structuralist idea of relation, in order to approach an interpretive notion of continuity and indeterminacy. This exploration highlights the key feature of actantial network distribution, which provides a bridge with the second methodological parts, dedicated to a “tuning” of the tools for the analysis. This section establishes a dialogue with current social sciences (like Actor-Network Theory, Situated action and Distributed Cognition), in order to define some observational methods for the documentation of social practices, which could be comprised in a semiotic ethnography framework. The last part, finally, focuses on the mediation and negotiation by which human actors are interacting with the varying conditions of the chosen environment, looking at people’s movements through space, their embodied dealings with the boundaries and the use of spatial artefacts as framing infrastructure of the site.

Prozessorientierte Modellierung des Wassertransports zur Bewertung von Hochwasserschutzmaßnahmen in bewaldeten Entstehungsgebieten

Im der vorliegenden Arbeit wurden die Einflüsse verschiedener wasserwirtschaftlicher und forstwirtschaftlicher Maßnahmen auf das Abflussverhalten von bewaldeten Gebieten untersucht. Der Schwerpunkt lag auf der Erfassung der Veränderungen im natürlichen System durch die jeweilige Maßnahme. Der Wassertransport wurde dabei auf der Prozessebene im Hangmaßstab betrachtet. Wichtige Erkenntnisse hinsichtlich der Hochwasserentstehung in bewaldeten Gebieten wurden gewonnen. Daraus abgeleitet wurde eine Bewertung sowohl der natürlich gegebenen Systemgrößen als auch der einzelnen Maßnahmen bezüglich einer Hochwasservorsorge in Wäldern.Berücksichtigt wurden Änderungen in der Bestockung und in der Feinerschließung der bewaldeten Flächen durch Wege und Wirtschaftstrecken. Die Wassertransportprozesse wurden im Gelände untersucht und in Abhängigkeit der globalen klimatischen Randbedingungen sowie den bodenhydraulischen und landnutzungsspezifischen Parameter mit dem Niederschlag-Abfluss-Modell CATFLOW simuliert.Die Abflussdynamik wird im untersuchten Maßstab im wesentlichen durch die gegebene Bodenhydraulik, die Vorfeuchte des Bodens bei einem Niederschlag und durch die Niederschlagsintensität bestimmt. Die vergleichende Untersuchung von zwei rheinland-pfälzischen Waldstandorten ergab, dass im Bereich Soonwald ein relativ hohes Hochwasserrisiko besteht. Hier wirken sich Eingriffe durch forstwirtschaftliche Bewirtschaftungsmaßnahmen stark aus. Im Bereich des Pfälzerwaldes ist nur ein sehr geringes Hochwasserrisiko gegeben, da hier die natürlichen Gebietseigenschaften die Eingriffe durch Bewirtschaftungsmaßnahmen überprägen.

Lateral spreading and associated slope processes in fractured rock slabs

Landslides of the lateral spreading type, involving brittle geological units overlying ductile terrains, are a common occurrence in the sandstone and limestone plateaux of the northern Apennines of Italy. These instability phenomena can become particularly risky, when historical towns and cultural heritage sites built on the top of them are endangered. Neverthless, the mechanisms controlling the developing of related instabilities, i.e. toppling and rock falls, at the edges of rock plateaux are not fully understood yet. In addition, the groundwater flow path developing at the contact between the more permeable units, i.e. the jointed rock slab, and the relatively impermeable clay-rich units have not been already studied in details, even if they may play a role in this kind of instability processes, acting as eventual predisposing and/or triggering factors. Field survey, Terrestrial Laser Scanner and Close Range Photogrammetry techniques, laboratory tests on the involved materials, hydrogeological monitoring and modelling, displacements evaluation and stability analysis through continuum and discontinuum numerical codes have been performed on the San Leo case study, with the aim to bring further insights for the understanding and the assessment of the slope processes taking place in this geological context. The current research permitted to relate the aquifer behaviour of the rocky slab to slope instability processes. The aquifer hosted in the fractured slab leads to the development of perennial and ephemeral springs at the contact between the two units. The related piping erosion phenomena, together with slope processes in the clay-shales led to the progressive undermining of the slab. The cliff becomes progressively unstable due to undermining and undergoes large-scale landslides due to fall or topple.

Detrital Zircon Evidence for Mixing of Mazatzal Province Age Detritus With Yavapai Age (ca. 1700-1740 Ma) and Older Detritus in the ca. 1650 Ma Mazatzal Province of Central New Mexico, USA

Preliminary detrital zircon age distributions from Mazatzal crustal province quartzite and schist exposed in the Manzano Mountains and Pedernal Hills of central New Mexico are consistent with a mixture of detritus from Mazatzal age (ca. 1650 Ma), Yavapai age (ca. 1720 Ma.), and older sources. A quartzite sample from the Blue Springs Formation in the Manzano Mountains yielding 67 concordant grain analyses shows two dominant age peaks of 1737 Ma and 1791 Ma with a minimum peak age of 1652 Ma. Quartzite and micaceous quartzite samples from near Pedernal Peak give unimodal peak ages of ca. 1695 Ma and 1738 Ma with minimum detrital zircon ages of ca. 1625 Ma and 1680 Ma, respectively. A schist sample from the southern exposures of the Pedernal Hills area gives a unimodal peak age of 1680 Ma with a minimum age of ca. 1635 Ma. Minor amounts of older detritus (>1800 Ma) possibly reflect Trans-Hudson, Wyoming, Mojave Province, and older Archean sources and aid in locating potential source terrains for these detrital zircon. The Blue Springs Formation metarhyolite from near the top of the Proterozoic section in the Manzano Mountains yields 71 concordant grains that show a preliminary U-Pb zircon crystallization age of 1621 ¿ 5 Ma, which provides a minimum age constraint for deposition in the Manzano Mountains. Normalized probability plots from this study are similar to previously reported age distributions in the Burro and San Andres Mountains in southern New Mexico and suggest that Yavapai Province age detritus was deposited and intermingled with Mazatzal Province age detritus across much of the Mazatzal crustal province in New Mexico. This data shows that the tectonic evolution of southwestern Laurentia is associated with multiple orogenic events. Regional metamorphism and deformation in the area must postdate the Mazatzal Orogeny and ca. 1610 Ma ¿ 1620 Ma rhyolite crystallization and is attributed to the Mesoproterozoic ca. 1400 ¿ 1480 Ma Picuris Orogeny.

IMPROVING FLOW DISTRIBUTION IN SMALL-SCALE WATER-SUPPLY SYSTEMS THROUGH THE USE OF FLOW-REDUCING DISCS AND METHODS FOR ANALYZING THE EFFECTIVENESS OF SOLAR POWERED PUMPING FOR A DRINKING WATER SUPPLY IN RURAL PANAMA

As continued global funding and coordination are allocated toward the improvement of access to safe sources of drinking water, alternative solutions may be necessary to expand implementation to remote communities. This report evaluates two technologies used in a small water distribution system in a mountainous region of Panama; solar powered pumping and flow-reducing discs. The two parts of the system function independently, but were both chosen for their ability to mitigate unique issues in the community. The design program NeatWork and flow-reducing discs were evaluated because they are tools taught to Peace Corps Volunteers in Panama. Even when ample water is available, mountainous terrains affect the pressure available throughout a water distribution system. Since the static head in the system only varies with the height of water in the tank, frictional losses from pipes and fittings must be exploited to balance out the inequalities caused by the uneven terrain. Reducing the maximum allowable flow to connections through the installation of flow-reducing discs can help to retain enough residual pressure in the main distribution lines to provide reliable service to all connections. NeatWork was calibrated to measured flow rates by changing the orifice coefficient (θ), resulting in a value of 0.68, which is 10-15% higher than typical values for manufactured flow-reducing discs. NeatWork was used to model various system configurations to determine if a single-sized flow-reducing disc could provide equitable flow rates throughout an entire system. There is a strong correlation between the optimum single-sized flow- reducing disc and the average elevation change throughout a water distribution system; the larger the elevation change across the system, the smaller the recommended uniform orifice size. Renewable energy can jump the infrastructure gap and provide basic services at a fraction of the cost and time required to install transmission lines. Methods for the assessment of solar powered pumping systems as a means for rural water supply are presented and assessed. It was determined that manufacturer provided product specifications can be used to appropriately design a solar pumping system, but care must be taken to ensure that sufficient water can be provided to the system despite variations in solar intensity.

Paleoglaciations in Anatolia: A Schematic Review and First Results

Anatolia is situated in the Eastern Mediterranean region between 36 – 42N and 26 – 45E. The geological records of paleoglaciations in the high terrains of Anatolia are key archives to quantify paleoclimate change in the Eastern Mediterranean area. The climate of the Eastern Mediterranean region is influenced by three main atmospheric systems: the main middle to high latitude westerlies, the mid-latitude subtropical high-pressure systems, and the monsoon climate. Glacial geological studies in Turkey have started in the late 19th century. Glacial deposits are found mainly in the eastern, northeastern and southern part of the Anatolian Peninsula. Anatolia is the fundamental element to understand the interactions between paleoenvironment, climatic variations, and development of the human societies. As the Taurus and Black Sea Mountains are sensitively situated for the paleoclimatic reconstructions, a chronostratigraphic framework on the paleoglaciation should be elaborated. The timing of the Last Glacial Maximum (LGM) in Anatolia is still unknown. Our first results from Kavron Valley (Kaçkar Mountains, NE Turkey) are encouraging for the reconstruction of paleoglaciations in Turkey and related paleoclimatological interpretations although it is presently difficult to pinpoint the classical Last Glacial Maximum – Younger Dryas – Little Ice Age moraine sequences in the field.

Bright moonlight triggers natal dispersal departures

Upon leaving their natal area, dispersers are confronted with unknown terrains. Species-specific perceptual ranges (i.e. the maximum distance from which an individual can perceive landscape features) play a crucial role in spatial movement decisions during such wanderings. In nocturnal animals that rely on vision, perceptual range is dramatically enhanced during moonlight, compared to moonless conditions. This increase of the perceptual range is an overlooked element that may be responsible for the successful crossing of unfamiliar areas during dispersal. The information gathered from 143 radio-tagged eagle owl Bubo bubo juveniles in Spain, Finland and Switzerland shows that, although the decision to initiate dispersal is mainly an endogenous phenomenon determined by the attainment of a given age (∼6 months), dispersers leave their birthplace primarily under the best light conditions at night, i.e. when most of the lunar disc is illuminated. This sheds new light into the mechanisms that may trigger dispersal from parental territory.

Potential desiccation cracks on Mars: A synthesis from modeling, analogue-field studies, and global observations

Potential desiccation polygons (PDPs) are polygonal surface patterns that are a common feature in Noachian-to-Hesperian-aged phyllosilicate- and chloride-bearing terrains and have been observed with size scales that range from cm-wide (by current rovers) to 10s of meters-wide. The global distribution of PDPs shows that they share certain traits in terms of morphology and geologic setting that can aid identification and distinction from fracturing patterns caused by other processes. They are mostly associated with sedimentary deposits that display spectral evidence for the presence of Fe/Mg smectites, Al-rich smectites or less commonly kaolinites, carbonates, and sulfates. In addition, PDPs may indicate paleolacustrine environments, which are of high interest for planetary exploration, and their presence implies that the fractured units are rich in smectite minerals that may have been deposited in a standing body of water. A collective synthesis with new data, particularly from the HiRISE camera suggests that desiccation cracks may be more common on the surface of Mars than previously thought. A review of terrestrial research on desiccation processes with emphasis on the theoretical background, field studies, and modeling constraints is presented here as well and shown to be consistent with and relevant to certain polygonal patterns on Mars.

Recurring slope lineae in equatorial regions of Mars

The presence of liquid water is a requirement of habitability on a planet. Possible indicators of liquid surface water on Mars include intermittent flow-like features observed on sloping terrains. These recurring slope lineae are narrow, dark markings on steep slopes that appear and incrementally lengthen during warm seasons on low-albedo surfaces. The lineae fade in cooler seasons and recur over multiple Mars years. Recurring slope lineae were initially reported to appear and lengthen at mid-latitudes in the late southern spring and summer and are more common on equator-facing slopes where and when the peak surface temperatures are higher. Here we report extensive activity of recurring slope lineae in equatorial regions of Mars, particularly in the deep canyons of Valles Marineris, from analysis of data acquired by the Mars Reconnaissance Orbiter. We observe the lineae to be most active in seasons when the slopes often face the sun. Expected peak temperatures suggest that activity may not depend solely on temperature. Although the origin of the recurring slope lineae remains an open question, our observations are consistent with intermittent flow of briny water. Such an origin suggests surprisingly abundant liquid water in some near-surface equatorial regions of Mars.

Etude des relations entre la pluie, le sol, le relief, la couverture végétale et l'érosion dans la région de Mandraka

Le relief accidenté, le climat agressif favorisé par l’Alizé, ainsi que l’étroite dépendance de la population de l’exploitation forestière et de l’exploitation agricole sans dispositifs de protection antiérosifs, sont les contextes qui permettent de dire que la région de Mandraka est sujette au problème d’érosion. L’étude a pour objectif de déterminer les relations entre les caractéristiques du sol, son mode d’occupation, les précipitations ainsi que l’érosion dans la région de Mandraka et ce en vue d’un aménagement rationnel. Des dispositifs pour la mesure de pertes en terre et de ruissellement ont été matérialisés sur des parcelles d’expérimentation. A cet effet, le choix de ces parcelles a porté sur le mode d’occupation du sol (sous terrains aménagés, sous « tavy », sous « savoka », et sous forêt naturelle), sur la similitude des pentes et sur leur localisation de manière à ce qu’elles soient situées sur les mi-versants. Les résultats ont montré que le sol dans cette région contient un taux de matière organique satisfaisant à élevé (2,41 à 3,74% de MO), lui permettant une bonne stabilité structurale (Is = 0,85 et K = 0,08). Les pertes en terre (0,13 à 20,93t/ha/an) et les ruissellements (0,3 à 5%) obtenus indiquent que l’érosion est faible à accélérée suivant le mode d’occupation du sol. En deux ans d’aménagement, les terrasses se sont stabilisées et les racines de Vetiveria zizanoides peuvent remplacer les fascines initialement installées pour tenir les talus. Toutefois, l’exposition du sol à la battance de la pluie et la mauvaise infiltration d’eau de ruissellement dans le sol accélèrent le phénomène d’érosion. Par ailleurs, il y a l’efficacité de la SCV sans brûlis bien qu’il s’agit de la première année d’expérience. Dans ces conditions, un plan d’aménagement simplifié a été proposé en vue (i) de protéger le sol contre la battance de la pluie, (ii) de réduire les transports solides par l’érosion et (iii) d’améliorer l’infiltration d’eau du sol.

Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U–Pb dating of rutile from the Ivrea–Verbano Zone, Italy

The Ivrea–Verbano Zone (IVZ), northern Italy, exposes an attenuated section through the Permian lower crust that records high-temperature metamorphism under lower crustal conditions and a protracted history of extension and exhumation associated partly with the Jurassic opening of the Alpine Tethys ocean. This study presents SHRIMP U–Pb geochronology of rutile from seven granulite facies metapelites from the base of the IVZ, collected from locations spanning ~35 km along the strike of Paleozoic fabrics. Rutile crystallised during Permian high-temperature metamorphism and anatexis, yet all samples give Jurassic rutile U–Pb ages that record cooling through 650–550 °C. Rutile age distributions are dominated by a peak at ~160 Ma, with a subordinate peak at ~175 Ma. Both ~160 and ~175 Ma age populations show excellent agreement between samples, indicating that the two distinctive cooling stages they record were synchronous on a regional scale. The ~175 Ma population is interpreted to record cooling in the footwall of rift-related faults and shear zones, for which widespread activity in the Lower Jurassic has been documented along the western margin of the Adriatic plate. The ~160 Ma age population postdates the activity of all known rift-related structures within the Adriatic margin, but coincides with extensive gabbroic magmatism and exhumation of sub-continental mantle to the floor of the Alpine Tethys, west of the Ivrea Zone. We propose that this ~160 Ma early post-rift age population records regional cooling following episodic heating of the distal Adriatic margin, likely related to extreme lithospheric thinning and associated advection of the asthenosphere to shallow levels. The partial preservation of the ~175 Ma age cluster suggests that the post-rift (~160 Ma) heating pulse was of short duration. The regional consistency of the data presented here, which is in contrast to many other thermochronometers in the IVZ, demonstrates the value of the rutile U–Pb technique for probing the thermal evolution of high-grade metamorphic terrains. In the IVZ, a significant decoupling between Zr-in-rutile temperatures and U–Pb ages of rutile is observed, with the two systems recording events ~120 Ma apart.

Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations

Context. Since August 2014, the OSIRIS Narrow Angle Camera (NAC) onboard the Rosetta spacecraft has acquired high spatial resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko, down to the decimeter scale. This paper focuses on the Imhotep region, located on the largest lobe of the nucleus, near the equator. Aims. We map, inventory, and describe the geomorphology of the Imhotep region. We propose and discuss some processes to explain the formation and ongoing evolution of this region. Methods. We used OSIRIS NAC images, gravitational heights and slopes, and digital terrain models to map and measure the morphologies of Imhotep. Results. The Imhotep region presents a wide variety of terrains and morphologies: smooth and rocky terrains, bright areas, linear features, roundish features, and boulders. Gravity processes such as mass wasting and collapse play a significant role in the geomorphological evolution of this region. Cometary processes initiate erosion and are responsible for the formation of degassing conduits that are revealed by elevated roundish features on the surface. We also propose a scenario for the formation and evolution of the Imhotep region; this implies the presence of large primordial voids inside the nucleus, resulting from its formation process.

Desiccation of phyllosilicate-bearing samples as analog for desiccation cracks on Mars: Experimental setup and initial results

The surface of Mars is host to many regions displaying polygonal crack patterns that have been identified as potential desiccation cracks. These regions are mostly within Noachian-aged terrains and are closely associated with phyllosilicate occurrences and smectites in particular. We have built a laboratory setup that allows us to carry out desiccation experiments on Mars-analog materials in an effort to constrain the physical and chemical properties of sediments that display polygonal cracks. The setup is complemented by a pre-existing simulation chamber that enables the investigation of the spectral and photometric properties of analog materials in Mars-like conditions. The initial experiments that have been carried out show that (1) crack patterns are visible in smectite-bearing materials in varying concentrations down to similar to 10% smectite by weight, (2) chlorides, and potentially other salts, delay the onset of cracking and may even block it from occurring entirely, and (3) the polygonal patterns, while being indicative of the presence of phyllosilicates, cannot be used to differentiate between various phyllosilicate-bearing deposits. However, their size-scale and morphology yields important information regarding their thickness and the hydrological conditions at the time of formation. Furthermore, the complementary spectral measurements for some of the analog samples shows that crack patterns may develop in materials with such low concentrations of smectites that would not be expected to be identified using remote-sensing instruments. This may explain the presence of polygonal patterns on Mars in sediments that lack spectral confirmation of phyllosilicates. (C) 2015 Elsevier Ltd. All rights reserved.