375 research outputs found

    Evaluation of multi-hazard map produced using MaxEnt machine learning technique

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    Natural hazards are diverse and uneven in time and space, therefore, understanding its complexity is key to save human lives and conserve natural ecosystems. Reducing the outputs obtained after each modelling analysis is key to present the results for stakeholders, land managers and policymakers. So, the main goal of this survey was to present a method to synthesize three natural hazards in one multi-hazard map and its evaluation for hazard management and land use planning. To test this methodology, we took as study area the Gorganrood Watershed, located in the Golestan Province (Iran). First, an inventory map of three different types of hazards including flood, landslides, and gullies was prepared using field surveys and different official reports. To generate the susceptibility maps, a total of 17 geo-environmental factors were selected as predictors using the MaxEnt (Maximum Entropy) machine learning technique. The accuracy of the predictive models was evaluated by drawing receiver operating characteristic-ROC curves and calculating the area under the ROC curve-AUCROC. The MaxEnt model not only implemented superbly in the degree of fitting, but also obtained significant results in predictive performance. Variables importance of the three studied types of hazards showed that river density, distance from streams, and elevation were the most important factors for flood, respectively. Lithological units, elevation, and annual mean rainfall were relevant for detecting landslides. On the other hand, annual mean rainfall, elevation, and lithological units were used for gully erosion mapping in this study area. Finally, by combining the flood, landslides, and gully erosion susceptibility maps, an integrated multi-hazard map was created. The results demonstrated that 60% of the area is subjected to hazards, reaching a proportion of landslides up to 21.2% in the whole territory. We conclude that using this type of multi-hazard map may be a useful tool for local administrators to identify areas susceptible to hazards at large scales as we demonstrated in this research

    Soil degradation and socioeconomic systems’ complexity: Uncovering the latent nexus

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    Understanding Soil Degradation Processes (SDPs) is a fundamental issue for humankind. Soil degradation involves complex processes that are influenced by a multifaceted ensemble of socioeconomic and ecological factors at vastly different spatial scales. Desertification risk (the ultimate outcome of soil degradation, seen as an irreversible process of natural resource destruction) and socioeconomic trends have been recently analyzed assuming “resilience thinking” as an appropriate interpretative paradigm. In a purely socioeconomic dimension, resilience is defined as the ability of a local system to react to external signals and to promote future development. This ability is intrinsically bonded with the socio-ecological dynamics characteristic of environmentally homogeneous districts. However, an evaluation of the relationship between SDPs and socioeconomic resilience in local systems is missing in mainstream literature. Our commentary formulates an exploratory framework for the assessment of soil degradation, intended as a dynamic process of natural resource depletion, and the level of socioeconomic resilience in local systems. Such a framework is intended to provide a suitable background to sustainability science and regional policies at the base of truly resilient local systems

    Population trends and urbanization. Simulating density effects using a local regression approach

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    7siopenDensity-dependent population growth regulates long-term urban expansion and shapes distinctive socioeconomic trends. Despite a marked heterogeneity in the spatial distribution of the resident population, Mediterranean European countries are considered more homogeneous than countries in other European regions as far as settlement structure and processes of metropolitan growth are concerned. However, rising socioeconomic inequalities among Southern European regions reflect latent demographic and territorial transformations that require further investigation. An integrated assessment of the spatio-temporal distribution of resident populations in more than 1000 municipalities (1961-2011) was carried out in this study to characterize density-dependent processes of metropolitan growth in Greece. Using geographically weighted regressions, the results of our study identified distinctive local relationships between population density and growth rates over time. Our results demonstrate that demographic growth rates were non-linearly correlated with other variables, such as population density, with positive and negative impacts during the first (1961-1971) and the last (2001-2011) observation decade, respectively. These findings outline a progressive shift over time from density-dependent processes of population growth, reflecting a rapid development of large metropolitan regions (Athens, Thessaloniki) in the 1960s, to density-dependent processes more evident in medium-sized cities and accessible rural regions in the 2000s. Density-independent processes of population growth have been detected in the intermediate study period (1971-2001). This work finally discusses how a long-term analysis of demographic growth, testing for density-dependent mechanisms, may clarify the intrinsic role of population concentration and dispersion in different phases of the metropolitan cycle in Mediterranean Europe.openPolinesi G.; Recchioni M.C.; Turco R.; Salvati L.; Rontos K.; Rodrigo-Comino J.; Benassi F.Polinesi, G.; Recchioni, M. C.; Turco, R.; Salvati, L.; Rontos, K.; Rodrigo-Comino, J.; Benassi, F

    A Conceptual Model for Planning and Management of Areas of Public Space and Meeting in Colombia

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    A refined investigation of new trends in urban analysis assuming a sustainable design of Areas of Public Space and Meeting (APSM) is a fundamental response to the challenges of inclusive and efficient cities. Even though the APSM are districts regarded as urban structuring systems, there is a lack of territorial planning instruments and conceptual models aimed at explaining their long-term dynamics. Based on these premises, we developed a conceptual model that articulates relevant variables of interest for the planning and management of APSM. The construction of the model includes the review and analysis of the literature and the validation process based on a consultation with a panel of experts on the subject. Our findings demonstrate that the existing research does not address the APSM issue adequately, and the methodologies proposed so far do not lead to accurate and comprehensive analyses of urban complexity in light of sustainability targets. There are only isolated, disjointed, and partial approaches to variables of interest, making it difficult to carry out holistic studies. Our technical and scientific proposal offers a framework for an exhaustive evaluation of these areas. The model has been structured according to the assumptions of urban sustainability and can be applied to diverse urban environments in South America

    Preliminary laboratory multi-scale investigation on performance of pervious concrete pavements and vegetated elements as storm water bio-filters and retention systems

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    The growing population in urban areas worldwide is having a severe impact on the environment and quality of life of inhabitants. To alleviate the impact on traditional transportation infrastructures, existing and future urban facilities must be more environmentally friendly and sustainable. One solution is to develop new “green transportation infrastructures” (GTI) as part of the urban storm water management system. Although technologies for GTI have been well-investigated, there is limited experience of their potential benefits globally and, specifically, in Italy. This work, funded by the Regione Piemonte in 2015 and supported by different areas of expertise, aimed at promoting new urban storm water systems through the retention, filtration, and restoration of natural soil water content. To this end, a laboratory investigation of porous road pavements (Figure 1), and vegetated boxes (Figure 2 and 3) that filter runoff pollutants from impervious pavements was conducted to examine ecological, hydraulic, and mechanical performance levels. Three different experimental scales (samples, columns, and boxes) for the two GTI technologies were considered. Samples were used to assess the permeability, void content, strength, and pollution reduction potential of different materials used to build full-scale bio-filter systems. The pollutant reduction was determined by the reduction in suspended solids and hydrocarbon concentration, with results confirming that it depends on filter type and permeability. The preliminary results are encouraging and show a high reduction in total suspended solids and hydrocarbon concentrations (from 65% to 99%). Concrete pervious pavements and vegetated bio-filter systems were reproduced in columns and boxes, combining materials and supports for biofilm bacteria (geotextile, plastic caps) to assess the abatement potential of pre-developed biofilm bacteria compared to systems where bacteria are present naturally. Hydraulic parameters (percolation time, void content, outflow rate) were estimated so as to provide basic design parameters for full-scale applications

    FUNCTIONAL CHARACTERIZATION OF A TOMATO GLUTHATHIONE S TRANSFERASE GENE AND ITS IMPLICATION IN THE PLANT RESPONSE TO ENVIRONMENTAL STRESSES

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    Mitigating the negative effects of abiotic stresses on crop productivity is pivotal in order to meet the global demand for food and other agricultural commodities. Abiotic stresses caused by deficiencies or excesses in environmental factors such as water, salt, light, and temperature can substantially reduce plant growth and productivity and even survival. Abiotic stresses were estimated to cause an overall yield loss of ~70% in key agricultural crops and global warming is even expected to further worsen food security. Abiotic stresses induce in plant cells increasing levels of reactive oxygen species (ROS) that are critical for stress signaling and mainly affect chloroplast protein synthesis and photosystem II repair. A plethora of antioxidants and antioxidant enzymes protect plant cells from oxidative stresses caused by an excess of ROS accumulation, thus engineering the cell redox cycle for enhancing the ROS-scavenging capacity might contribute to empower plant stress tolerance. Glutathione S-transferases (GSTs) is a multigene superfamily with diverse cellular mechanisms and metabolic functions and has been considered as one of the key members of plant stress modulation pathways. Our goal is to investigates the role of a tomato glutathione S-transferase (GST - Solyc07g056420) gene in controlling plant stress response. Tobacco lines overexpressing the Solyc07g056420 coding sequence (OE) accumulated significantly higher levels of hydrogen peroxide in leaves and decreased leaf levels of flavonoids, chlorophyll A and antioxidant capacity compared with control plants. OE 40 days old plants underwent differential watering treatments, i.e. full reintegration of water lost by evapo transpiration (FWR) and restitution of 50% of lost water (HWR). Under HWR conditions, OE plants showed a reduced occurrence of leaf injuries and responded to drought with a significantly higher increase in leaf chlorophyll A, chlorophyll B, hydrogen peroxide and antioxidant capacity compared to control plants. These results suggested that the hyper-accumulation of H2O2 induced in leaves by the overexpression of the Solyc07g056420 coding sequence and compensated by the adjusting the antioxidant capacity might lead to an enhancement of plant responsiveness to drought. Ongoing experiments will further investigate the functional role of the tomato Solyc07g056420 within the stress signaling network and its possible involvement in the modulation of plant response to other environmental stresses

    2007 : el año del Sol

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    Sumario : La estrella imprescindible.-- Pero, ¿cómo medimos el campo magnético?.-- El interior de las manchas solares.-- CIENCIA: PILARES E INCERTIDUMBRES.-- DECONSTRUCCIÓN Y otros ENSAYOS : El satélite que indagará en el campo magnético solar.-- ACTUALIDAD.-- ENTRE BASTIDORES.-- HISTORIAS DE ASTRONOMÍA : Una predicción, un cristal, un derrumbe y un incendio.-- HOMENAJE A LUCAS LARA.-- ACTIVIDADES IAA.-- El increíble y asombroso viaje de Fotón.Esta revista se publica con la ayuda de la Acción Complementaria CCT005-06-00178 del Programa Nacional de Fomento de la Cultura Científica y Tecnológica.N

    The November 2017 Mw 5.5 Pohang earthquake: a possible case of induced seismicity in South Korea

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    The Mw 5.5 earthquake that struck South Korea in November 2017 was one of the largest and most damaging events in this country over the last century. Its proximity to an Enhanced Geothermal Systems site, where high pressure hydraulic injection had been performed during the previous two years, raises the possibility that this earthquake was anthropogenic. We have combined seismological and geodetic analyses to characterize the mainshock and its largest aftershocks, constrain the geometry of this seismic sequence and shed light on its casual factors. According to our analysis it seems plausible that the occurrence of this earthquake was influenced by these industrial activities. Finally we found that the earthquake transferred static stress to larger nearby faults, potentially increasing the seismic hazard in the area

    Improvements in tribological and anticorrosion performance of porous Ti-6Al-4V via PEO coating

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    Producción CientíficaMedical implants manufactured using biomaterial Ti-6Al-4V exhibit some disadvantages. Its higher elastic modulus than that of natural bone can cause stress shielding problems. This can be avoided using Ti-6Al-4V with pores in the implant structure. However, poor corrosion and tribocorrosion behaviors are yielded because of the large area exposed to the medium. To mitigate both issues, coating technologies can be applied. The plasma electrolytic oxidation (PEO) process is a cost-effective process that has been used successfully in nonporous Ti alloys. In this study, two PEO coatings with different amounts of Ca/P are used. However, reports regarding their application in porous materials are scarce. The effects of PEO treatments on corrosion and tribocorrosion in Ti-6Al-4V powder metallurgy are analyzed herein. The porous materials provide an efficient surface for PEO coatings, as demonstrated via scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the porosity of the substrates improved the adherence of the coatings. The corrosion resistance measured via electrochemical impedance spectroscopy confirmed the beneficial effect of the coatings, particularly for long exposure time. The lower roughness, small pore size, and more compact film observed in the PEO-Ca/P sample resulted in favorable tribological and corrosion properties.Ministerio de Educación y Ciencia (project RTI2018-097990-B-I00)Junta de Castilla y León (projects VA275P18 and VA044G19

    Morphometric and microstructural characteristics of hippocampal subfields in mesial temporal lobe epilepsy and their correlates with mnemonic discrimination.

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    Pattern separation (PS) is a fundamental aspect of memory creation that defines the ability to transform similar memory representations into distinct ones, so they do not overlap when storing and retrieving them. Experimental evidence in animal models and the study of other human pathologies have demonstrated the role of the hippocampus in PS, in particular of the dentate gyrus (DG) and CA3. Patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HE) commonly report mnemonic deficits that have been associated with failures in PS. However, the link between these impairments and the integrity of the hippocampal subfields in these patients has not yet been determined. The aim of this work is to explore the association between the ability to perform mnemonic functions and the integrity of hippocampal CA1, CA3, and DG in patients with unilateral MTLE-HE. To reach this goal we evaluated the memory of patients with an improved object mnemonic similarity test. We then analyzed the hippocampal complex structural and microstructural integrity using diffusion weighted imaging. Our results indicate that patients with unilateral MTLE-HE present alterations in both volume and microstructural properties at the level of the hippocampal subfields DG, CA1, CA3, and the subiculum, that sometimes depend on the lateralization of their epileptic focus. However, none of the specific changes was found to be directly related to the performance of the patients in a pattern separation task, which might indicate a contribution of various alterations to the mnemonic deficits or the key contribution of other structures to the function. we established for the first time the alterations in both the volume and the microstructure at the level of the hippocampal subfields in a group of unilateral MTLE patients. We observed that these changes are greater in the DG and CA1 at the macrostructural level, and in CA3 and CA1 in the microstructural level. None of these changes had a direct relation to the performance of the patients in a pattern separation task, which suggests a contribution of various alterations to the loss of function
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