127 research outputs found

    Assessment of the Carbon Stock in Pine Plantations in Southern Spain through ALS Data and K-Nearest Neighbor Algorithm Based Models

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    Accurate estimation of forest biomass to enable the mapping of forest C stocks over large areas is of considerable interest nowadays. Airborne laser scanning (ALS) systems bring a new perspective to forest inventories and subsequent biomass estimation. The objective of this research was to combine growth models used to update old inventory data to a reference year, low-density ALS data, and k-nearest neighbor (kNN) algorithm Random Forest to conduct biomass inventories aimed at estimating the C sequestration capacity in large Pinus plantations. We obtained a C stock in biomass (Wt-S) of 12.57 Mg·ha−1, ranging significantly from 19.93 Mg·ha−1 for P. halepensis to 49.05 Mg·ha−1 for P. nigra, and a soil organic C stock of the composite soil samples (0–40 cm) ranging from 20.41 Mg·ha−1 in P. sylvestris to 37.32 Mg·ha−1 in P. halepensis. When generalizing these data to the whole area, we obtained an overall C-stock value of 48.01 MgC·ha−1, ranging from 23.96 MgC·ha−1 for P. halepensis to 58.09 MgC·ha−1 for P. nigra. Considering the mean value of the on-site C stock, the study area sustains 1,289,604 Mg per hectare (corresponding to 4,732,869 Mg CO2), with a net increase of 4.79 Mg·ha−1·year−1. Such C cartography can help forest managers to improve forest silviculture with regard to C sequestration and, thus, climate change mitigation

    WSPH and ISPH Calculations of a Counter-Rotating Vortex Dipole

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    Viscosity and vorticity are magnitudes playing an important role in many engineering physical phenomena such as: boundary layer separation, transition flows, shear flows, etc., demonstrating the importance of the vortical viscous flows commonly used among the SPH community. The simulation presented here, describes the physics of a pair of counter-rotating vortices in which the strain field felt by each vortex is due to the other one. Different from the evolution of a single isolated vortex, in this case each vortex is subjected to an external stationary strain field generated by the other, making the streamlines deform elliptically. To avoid the boundary influence, a large computational domain has been used ensuring insignificant effect of the boundary conditions on the solution. The performance of the most commonly used viscous models in simulating laminar flows, Takeda’s (TVT), Morris’ (MVT) and Monaghan-Cleary’s (MCGVT) has been discussed comparing their results. These viscous models have been used under two different compressibility hypotheses. Two cases have been numerically analyzed in this presentation. In the first case, a 2D system of two counter-rotating Lamb O seen vortices is considered. At first, the system goes through a rapid relaxation process in which both vortices equilibrate each other. This quasi-steady state is obtained after the relaxation phase is advected at a constant speed and slowly evolves owing to viscous diffusion. The results of the different Lamb-O seen numerical solutions have been validated with good agreement by comparison with the numerical results of a finite element code (ADFC) solution. A second case, somewhat more complex than the previous one, is a 3D Batchelor vortex dipole obtained by adding an axial flow to the system of the first case. The Batchelor vortex model considered here is a classical option normally used to model the structure of trailing vortices in the far-wake of an aircraft

    Principles and medical applications of gene editing by CRISPR / Cas

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    CRISPR/Cas technology is a simple, fast and extremely efficient method for gene editing. In order to describe the principles and medical application of this technology, a bibliographic review was carried out in Pubmed, SciELO, academic Google and the Cochrane Library, with the descriptors “gene editing”, “genome editing”, “CRISPR-Cas systems”, and “CRISPR-associated protein 9”. The CRISPR/Cas9 system comprises a Cas endonuclease and two types of RNA. Cas cuts the invading phage DNA into segments, which are integrated into the CRISPR sequence as spacers. Subsequently, the CRISPR sequence is transcribed to generate crRNA and tracrRNA, which form a double-stranded RNA structure that recruits Cas for cleavage. The introduction of the system into the cell interior occurs with plasmids, RNA or ribonucleoproteins. A nuclear localization sequence allows CRISPR / Cas9 to enter the nucleus. CRISPR/Cas9 technology is an efficient tool for precise gene editing with great impact on scientific research

    A simple and effective 1D-element discrete-based method for computational bone remodeling

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    This is an Accepted Manuscript of an article published by Taylor & Francis Group in Computer Methods in Biomechanics and Biomedical Engineering on 2022, available online at: http://www.tandfonline.com/10.1080/10255842.2021.1943370.In-silico models applied to bone remodeling are widely used to investigate bone mechanics, bone diseases, bone-implant interactions, and also the effect of treatments of bone pathologies. This paper proposes a new methodology to solve the bone remodeling problem using one-dimensional (1D) elements to discretize trabecular structures more efficiently for 2D and 3D domains. An Euler integration scheme is coupled with the momentum equations to obtain the evolution of material density at each step. For the simulations, the equations were solved by using the finite element method, and two benchmark tests were solved varying mesh parameters. Proximal femur and calcaneus bone were selected as study cases given the vast research available on the topology of these bones, and compared with the anatomical features of trabecular bone reported in the literature. The presented methodology has proven to be efficient in optimizing topologies of lattice structures; It can predict the trend of formation patterns of the main trabecular groups from two different cancellous bones (femur and calcaneus) using domains set up by discrete elements as a starting point. Preliminary results confirm that the proposed approach is suitable and useful in bone remodeling problems leading to a considerable computational cost reduction. Characteristics similar to those encountered in topological optimization (TO) algorithms were identified in the benchmark tests as well, showing the viability of the proposed approach in other applications such as bio-inspired design.Peer ReviewedPostprint (author's final draft

    Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains

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    The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fmicb.2015.00871Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184, and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues, and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed.Work in this study was supported by the ERANET Pathogenomics Program through the ADHERS-Signature Project (reference: BIO2008-04419-E)Peer reviewe

    Information and studies on education as an object of territorial cooperation (II): Cooperation in Europe through the Eurydice network as a model of cooperation between education administrations through the spanish network Redie

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    On the occasion of the European double ephemeris which JOSPOE is currently celebrating, the Eurydice Spanish Unit (Eurydice Spain-REDIE) has wished to accept their invitation to participate in this extraordinary issue alongside the European Unit, the information network coordinator on European Commission’s education. The reason is, none other than, because of the good model of cooperation it offers Spain when it comes to reporting on education management. The first article has been prepared by the heads of both units, describing the trajectory of the European and Spanish information networks on education, evolving into what they are today; the second article has been written by analysts from the European unit and technical and external experts from the Spanish unit, and presents the work they carry out in order to fulfil commitments undertaken through the annual work plansCon motivo de la doble efeméride europea que celebra JOSPOE, la Unidad española de Eurydice (Eurydice España-REDIE) ha querido responder a la invitación a participar en este número extraordinario de la mano de la Unidad europea, coordinadora de la Red de información sobre educación de la Comisión Europea. La razón no es otra que el buen modelo de cooperación que ofrece a España a la hora de informar sobre la gestión de la educación. El primer artículo está elaborado por los responsables de ambas Unidades y describe la trayectoria de las redes europea y española de información sobre educación hasta convertirse en lo que son hoy en día; este segundo está redactado por los analistas de la Unidad europea y los técnicos y expertos externos de la Unidad española, y presenta el trabajo que realizan con el fin de dar cumplimiento a los compromisos adquiridos a través de los planes de trabajo anuale

    Estado, desarrollo y tendencias de los estudios en acústica de la fauna en Colombia

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    Acoustic signals are one of the most important ways of communication for fauna. The study of acoustic signals constitutes a valuable tool to obtain information on ecology, behavior, taxonomic identification, and the effect of human activities in natural environments and different animal species. Furthermore, it offers the possibility of quantifying and monitoring biodiversity in different Colombian ecosystems. In this work, we present an analysis of the research on bioacoustics that have been developed in Colombia, to establish a baseline, identify gaps in knowledge, strengths, weaknesses and discuss future challenges for bioacoustics research in Colombia. We searched information on scientific publications, degree papers, and electronic database conference presentations, using different keywords. We obtained 321 results;studies using acoustic tools are much more common in birds (36.4%) and amphibians (35%) than in any other taxonomic group, and there is a bias towards studying bioacoustics in the Andean region. However, this is a field with growing interest, and, therefore, there is a need for collaborative and multidisciplinary work, a consensus on methodologies, along with the strengthening and enrichment of the country's sound collections.Las señales acústicas son una de las formas de comunicación más importante en la fauna, incluso en la ubicación espacial de los individuos y sus presas. El estudio de las señales acústicas fortalece los campos de investigación en ecología, comportamiento, identificación taxonómica, uso de hábitat e incluso el efecto de las actividades humanas sobre diferentes especies animales. Además, es una herramienta para la cuantificación y monitoreo de la biodiversidad. En este trabajo presentamos un análisis de los estudios basados en bioacústica que se han desarrollado en Colombia, con el fin de establecer una línea base e identificar vacíos en el conocimiento, sus fortalezas y debilidades, para discutir los retos futuros para el desarrollo de la investigación sobre bioacústica en el país. Nuestra búsqueda de información se concentró en publicaciones de tipo científico, trabajos de grado y presentaciones en conferencias, a partir de plataformas de datos electrónicos, usando diferentes palabras claves. En total obtuvimos 321 trabajos, en los que los grupos taxonómicaos más estudiados fueron las aves (36.4%) y los anfibios (35%). La mayoría de los trabajos se concentran en la región Andina (63%). La bioacústica es un campo con un creciente interés y, por ende, resulta necesario el trabajo colaborativo y multidisciplinario, la consolidación en las metodologías y el fortalecimiento y enriquecimiento de las colecciones de sonidos del país

    Niche differentiation drives microbial community assembly and succession in full-scale activated sludge bioreactors

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    Network models and community phylogenetic analyses are applied to assess the composition, structure, and ecological assembly mechanisms of microbial communities. Here we combine both approaches to investigate the temporal dynamics of network properties in individual samples of two activated sludge systems at different adaptation stages. At initial assembly stages, we observed microbial communities adapting to activated sludge, with an increase in network modularity and co-exclusion proportion, and a decrease in network clustering, here interpreted as a consequence of niche specialization. The selective pressure of deterministic factors at wastewater treatment plants produces this trend and maintains the structure of highly functional and specialized communities responding to seasonal environmental changes
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