1,412 research outputs found

    Use of Lagrangian simulations to hindcast the geographical position of propagule release zones in a Mediterranean coastal fish

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    The study of organism dispersal is fundamental for elucidating patterns of connectivity between populations, thus crucial for the design of effective protection and management strategies. This is especially challenging in the case of coastal fish, for which information on egg release zones (i.e. spawning grounds) is often lacking. Here we assessed the putative location of egg release zones of the saddled sea bream (Oblada melanura) along the south-eastern coast of Spain in 2013. To this aim, we hindcasted propagule (egg and larva) dispersal using Lagrangian simulations, fed with species-specific information on early life history traits (ELTs), with two approaches: 1) back-tracking and 2) comparing settler distribution obtained from simulations to the analogous distribution resulting from otolith chemical analysis. Simulations were also used to assess which factors contributed the most to dispersal distances. Back-tracking simulations indicated that both the northern sector of the Murcia region and some traits of the North-African coast were hydrodynamically suitable to generate and drive the supply of larvae recorded along the coast of Murcia in 2013. With the second approach, based on the correlation between simulation outputs and field results (otolith chemical analysis), we found that the oceanographic characteristics of the study area could have determined the pattern of settler distribution recorded with otolith analysis in 2013 and inferred the geographical position of main O. melanura spawning grounds along the coast. Dispersal distance was found to be significantly affected by the geographical position of propagule release zones. The combination of methods used was the first attempt to assess the geographical position of propagule release zones in the Mediterranean Sea for O. melanura, and can represent a valuable approach for elucidating dispersal and connectivity patterns in other coastal species

    Spatial genetic structure in the saddled sea bream (Oblada melanura [Linnaeus, 1758]) suggests multi-scaled patterns of connectivity between protected and unprotected areas in the Western Mediterranean Sea

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    Marine protected areas (MPAs) and networks of MPAs are advocated worldwide for the achievement of marine conservation objectives. Although the knowledge about population connectivity is considered fundamental for the optimal design of MPAs and networks, the amount of information available for the Mediterranean Sea is currently scarce. We investigated the genetic structure of the saddled sea bream ( Oblada melanura) and the level of genetic connectivity between protected and unprotected locations, using a set of 11 microsatellite loci. Spatial patterns of population differentiation were assessed locally (50-100 km) and regionally (500-1000 km), considering three MPAs of the Western Mediterranean Sea. All values of genetic differentiation between locations (Fst and Jost's D) were non-significant after Bonferroni correction, indicating that, at a relatively small spatial scale, protected locations were in general well connected with non-protected ones. On the other hand, at the regional scale, discriminant analysis of principal components revealed the presence of a subtle pattern of genetic heterogeneity that reflects the geography and the main oceanographic features (currents and barriers) of the study area. This genetic pattern could be a consequence of different processes acting at different spatial and temporal scales among which the presence of admixed populations, large population sizes and species dispersal capacity, could play a major role. These outcomes can have important implications for the conservation biology and fishery management of the saddled sea bream and provide useful information for genetic population studies of other coastal fishes in the Western Mediterranean Sea

    An introduction to a porous shape memory alloy dynamic data driven application system

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    Shape Memory Alloys are capable of changing their crystallographic structure due to changes of temperature and/or stress. Our research focuses on three points: (1) Iterative Homogenization of Porous SMAs: Development of a Multiscale Model of porous SMAs utilizing iterative homogenization and based on existing knowledge of constitutive modeling of polycrystalline SMAs. (2) DDDAS: Develop tools to turn on and off the sensors and heating unit(s), to monitor on-line data streams, to change scales based on incoming data, and to control what type of data is generated. The application must have the capability to be run and steered remotely. (3) Modeling and applications of porous SMA: Vibration isolation devices with SMA and porous SMA components for aerospace applications will be analyzed and tested. Numerical tools for modeling porous SMAs with a second viscous phase will be developed. The outcome will be a robust, three-dimensional, multiscale model of porous SMA that can be used in complicated, real-life structural analysis of SMA components using a DDDAS framework. © 2012 Published by Elsevier Ltd

    Los recursos combustibles arqueolĂłgicos en Loma Alta : (Catamarca, Argentina)

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    El presente trabajo se basa en el estudio de los restos carbonizados producto de las combustiones que tuvieron lugar en el sitio arqueológico Loma Alta (Provincia de Catamarca, Argentina) y su variabilidad. Para ello se procede a la identificación de los taxones presentes entre los carbones depositados los estratos de dicho sitio, cuya antigüedad se estima en 1400 años AP en base a los resultados obtenidos sobre 7 muestras fechadas radiocarbónicamente (Scattolin, 2004). El material carbonizado fue preparado en laboratorio, examinándose las tres secciones diagnósticas en el Microscopio Electrónico de Barrido (MEB), Los fragmentos fueron identificados como procedentes de los géneros Bulnesia, Lycium, Larrea, Bougainvillea, Prosopis. Uno de los ejemplares corresponde a un espécimen de la familia Cactaceae. Los resultados se ponen en relación con la disponibilidad actual de recursos combustibles en las áreas vecinas al sitio, y su aprovechamiento por parte de los antiguos pobladores de Loma Alta.Fil: Calo, C. Marilin. Universidad de Buenos AiresFil: Rivera, Stella Marias. Universidad Nacional de la Plata. Facultad de Ciencias Agrarias y ForestalesFil: Scattolin, María Cristina. Universidad de Buenos Aire

    A model of discriminant analysis on the basis of descriptor variables for the ampelography of Vitis sp.

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    Use of descriptor variables in ampelography is recommended to simplify recording of data and to enable useful comparisons. Parametric assumptions are, however, poorly satisfied especially with regard to statistical interference. In the paper some statistical procedures to improve the discriminant ability of descriptor variables are considered. The use of variances and covariances of variety by year interactions is suggested for the error matrix within a multiple discriminant analysis procedure. The adequacy of this model is verified in a 3-year experiment with Italian wine varieties. The discriminant power, as evaluated on the basis of the estimated distances among varieties, is satisfactory

    Validation of a bioanalytical method for the determination of synthetic and natural cannabinoids (New psychoactive substances) in oral fluid samples by means of hplc-ms/ms

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    New psychoactive substances (NPS) represent an important focus nowadays and are continually produced with minimal structural modifications in order to circumvent the law and increase the difficulty of identifying them. Moreover, since there are a high number of different compounds, it is arduous to develop analytical screening and/or confirmation methods that allow the identification and quantification of these compounds. The aim of this work is to develop and validate a bioanalytical method for detecting new synthetic drugs in biological samples, specifically oral fluid, using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) with minimal sample pretreatment. Oral fluid samples were simply centrifuged and denaturized with different rapid procedures before injection into the LC-MS/MS system. Calibration curves covered a linear concentration range from LOQ to 100 ng/mL. Validation parameters such as linearity, precision, accuracy, selectivity, matrix effect and thermal stability were evaluated and showed satisfactory results, in accordance with US Food & Drug Administration guidelines. The inter-day analytical bias and imprecision at two levels of quality control (QC) were within ±15% for most compounds. This method was able to identify and calculate the concentration of 10 NPS validated in this biological sample, even in the presence of matrix effect

    Influence of Different Evolutive Forces on GDF5 Gene Variability

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    The GDF5 gene is involved in the development of skeletal elements, synovial joint formation, tendons, ligaments, and cartilage. Several polymorphisms are present within the gene, and two of them, rs143384 and 143383, were reported to be correlated with osteoarticular disease or muscle flexibility. The aim of this research is to verify if the worldwide distribution of the rs143384 polymorphism among human populations was shaped by selective pressure, or if it was the result of random genetic drift events. Ninety-four individuals of both the male and female sexes, 18–28 years old, from Sardinia were analyzed. We observed the following genotype frequencies: 28.72% of AA homozygotes, 13.83% of GG homozygotes, and 57.45% of AG heterozygotes. The allele frequencies were 0.574 for allele A and 0.426 for allele G. The relationships between the populations were verified via Multidimensional Scaling (MDS). Our data show (i) a clear heterogeneity within the African populations; (ii) a strong differentiation between the African populations and the other populations; and that (iii) the Sardinian population is placed within the European cluster. To reveal possible traces of selective pressure, the Population Branch Statistic (PBS) was calculated; both the rs143384 and 143383 SNPs have low PBS values, suggesting that there are no signals of selective pressure in those areas of the gene

    A staged screening of registered drugs highlights remyelinating drug candidates for clinical trials

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    There is no treatment for the myelin loss in multiple sclerosis, ultimately resulting in the axonal degeneration that leads to the progressive phase of the disease. We established a multi-tiered platform for the sequential screening of drugs that could be repurposed as remyelinating agents. We screened a library of 2,000 compounds (mainly Food and Drug Administration (FDA)-approved compounds and natural products) for cellular metabolic activity on mouse oligodendrocyte precursors (OPC), identifying 42 molecules with significant stimulating effects. We then characterized the effects of these compounds on OPC proliferation and differentiation in mouse glial cultures, and on myelination and remyelination in organotypic cultures. Three molecules, edaravone, 5-methyl-7-methoxyisoflavone and lovastatin, gave positive results in all screening tiers. We validated the results by retesting independent stocks of the compounds, analyzing their purity, and performing dose-response curves. To identify the chemical features that may be modified to enhance the compounds' activity, we tested chemical analogs and identified, for edaravone, the functional groups that may be essential for its activity. Among the selected remyelinating candidates, edaravone appears to be of strong interest, also considering that this drug has been approved as a neuroprotective agent for acute ischemic stroke and amyotrophic lateral sclerosis in Japan

    Which learning activities enhance physical therapist practice? Part 2: Systematic review of qualitative studies and thematic synthesis

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    Objective. Post-professional physical therapy expertise requires career-long participation in learning activities. Understanding physical therapists’ lived experience of learning activities provides novel insight into how best to enhance physical therapist practice from the perspective of the learner. The purpose of this study was to explore qualified physical therapists’ experiences, beliefs, and perspectives with regard to learning activities and professional development. Methods. Eight databases were searched for studies published from inception through December 2018. Study selection included mixed-methods and qualitative studies exploring physical therapists’ experiences, perspectives, beliefs and attitudes. Thematic synthesis was performed, and the GRADE-Confidence in the Evidence from Reviews of Qualitative research (CERQual) was used to assess the level of confidence in the findings. Forty-one studies with 719 participants were included. Results. The key findings include physical therapists’ perceptions that worthwhile post professional learning requires more than attendance at professional development courses. Physical therapists perceived that worthwhile learning requires connection with others and being “taken out of ones’ comfort zone.” Sufficient time and accessible, trustworthy resources were also valued. Conclusions. Moderate- to low-level evidence suggests that the choice of professional development activities and education design for qualified physical therapists should consider the inclusion of connected activities, activities that take participants out of comfort zones, time to practice, and trustworthy resources that are easily accessible. Future research should evaluate the effectiveness of learning activities encompassing these factors, prioritizing those that minimize the barriers of time and distance. Impact. This study adds to the profession’s understanding of physical therapists’ lived experience of learning activities, providing novel insight into how best to enhance physical therapist practice from the perspective of the learner
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