767 research outputs found

    Freeze-thaw durability of recycled concrete from construction and demolition wastes

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    Road engineering is one of the most accepted applications for concrete including recycled aggregates from construction and demolition wastes as a partial replacement of the natural coarse aggregates. Amongst the durability concerns of such application, the deterioration due to freeze-thaw cycles is one of the most important causes decreasing the life span of concrete in countries with a continental climate. Moreover, the use of de-icing salts, which is a common practice to prevent ice formation on roadways and walkways, increases the superficial degradation of concrete due to frost-salt scaling. Thus, this paper aims to assess the resistance to frost salt with de-icing salts of two recycled concrete mixtures containing a 50% replacement of the conventional gravel by recycled aggregates both of mixed and ceramic nature, i.e. containing ceramic percentages of 34% and 100%, in comparison to a conventional concrete made with siliceous gravel. Therefore, the surface scaling was evaluated based on EN 1339 (2004) on 28 days cured cylinders, exposed to 7, 14, 21 and 28 freeze-thaw cycles in the presence of sodium chloride solution. Given that no airentraining admixture was used in any of the mixtures, the scaling of both conventional and recycled concretes exceeded the 1 kg/m2 limit established by the European standard. Nonetheless, for the casting surface, the recycled concrete with low ceramic content exhibited a similar behaviour to the conventional concrete, whereas the performance of the recycled concrete with high ceramic content was better. However, as expected, trowelled surfaces showed a worse performance and both recycled concretes had a lower freeze-thaw durability than the conventional mixture. In any case, the results suggested that the composition of the recycled aggregates could be used as a factor to limit the differences in performance between recycled and conventional mixtures

    Designing an experimental HIV/HCV intervention to promote the safe re-use of drug preparation materials by injection drug users in Puerto Rico

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    Injection drug users (IDUs) in San Juan, Puerto Rico are characterized by high rates of daily injecting, injection of shared drugs, re-use of injection syringes, and use of shooting galleries. They lack adequate access to new injection syringes and drug preparation equipment, and experience elevated rates of HIV and HCV infection. Between April and August, 2006, researchers and active IDUs collaborated in the development of an experimental HIV/HCV intervention aimed at identifying drug preparation items and practices that will enable IDUs to make drug solutions without potentially contaminated injection syringes contacting materials used to prepare drugs. The collaboration involved discussing and testing a variety of drug preparation items and practices in office and community settings. The process was repeated until concerns that had been raised were resolved, and a tentative set of intervention items and practices to be evaluated in a community field trial was identified. Throughout, a strong emphasis was placed on the capacity of an item or practice to address common problems confronted by IDUs (blunted needles, clogged syringes, injected particles) in addition to the core aim of reducing contamination of preparation materials by blood in injection syringes

    The effect of developmental stage on eggshell thickness variation in endangered falcons

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    We compared eggshell thickness of hatched eggs with that of non-developed eggs in endangered falcon taxa to explore the effect of embryo development on eggshell thinning. To our knowledge, this has never been examined before in falcons, despite the fact that eggshell thinning due to pollutants and environmental contamination is often considered the most common cause of egg failure in falcons. Because of the endangered nature of these birds, and the difficulty in gaining access to the nests and their eggs, there is a large gap in our knowledge regarding eggshell thickness variation and the factors affecting it. We used a linear mixed-effects (LME) model to explore the variation in eggshell thickness (n=335 eggs) in relation to the developmental stage of the eggs, but also in relation to the falcon taxa, the laying sequence and the study zone. Female identity (n=69) and clutch identity (n=98) were also included in the LME model. Our results are consistent with the prediction that eggshell thickness decreases during incubation because of the important effect of calcium uptake by the embryo during development. Our results also show that eggs laid later in the sequence had significantly thinner eggshells. In this study, we provide the first quantitative data on eggshell thickness variation of hatched eggs in different falcon taxa that were not subjected to contamination or food limitation (i.e., bred under captive conditions). Because eggshell thickness strongly influences survival and because the species examined in this study are endangered, our data represent a valuable control for future studies on the effects of pollution on eggshells from wild populations and thus are an important contribution to the conservation of falcons. © 2010 Elsevier GmbH.Peer Reviewe

    Litiasis urológicas en la provincia de Huelva

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    Se ha realizado el estudio de la frecuencia de los componentes minerales en 500 casos de litiasis urológicas, así como la incidencia de éstas y los cita los componentes de acuerdo con la edad y sexo. Se observa que la mayor parte de los casos se deben a oxalato cálcico, seguido de ácido úrico, siendo más frecuentes las litiasis entre los 40 y 60 años, presentándose en número ligeramente mayor en el sexo masculino.A survey has been made about the frecuency of mineral compounds in 500 cases of urological lithiasis as well as the incidence of these and the aforementioned compounds accordign to age and sexo Most of the cases are due to calcium oxalate, uric acid was founf as the second compound. Lithiasis frecuency is higher in persons between forty and sixty years and slighty bigger in males

    Early diversification and permeable species boundaries in the Mediterranean firs

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    BACKGROUND AND AIMS: Inferring the evolutionary relationships of species and their boundaries is critical in order to understand patterns of diversification and their historical drivers. Despite Abies (Pinaceae) being the second most diverse group of conifers, the evolutionary history of Circum-Mediterranean firs (CMF) remains under debate. METHODS: We used restriction site associated DNA sequencing (RAD-seq) on all proposed CMF taxa to investigate their phylogenetic relationships and taxonomic status. KEY RESULTS: Based on thousands of genome-wide SNPs, we present here the first formal test of species delimitation, and the first fully resolved, complete species tree for CMF. We discovered that all previously recognized taxa in the Mediterranean should be treated as independent species, with the exception of A. tazaotana and A. marocana. An unexpectedly early pulse of speciation in the Oligocene-Miocene boundary is here documented for the group, pre-dating previous hypotheses by millions of years, revealing a complex evolutionary history encompassing both ancient and recent gene flow between distant lineages. CONCLUSIONS: Our phylogenomic results contribute to shed light on conifers' diversification. Our efforts to resolve the CMF phylogenetic relationships help refine their taxonomy and our knowledge of their evolutio

    Litiasis urológicas en la provincia de Huelva

    Get PDF
    A survey has been made a bout the frecuency of mineral compounds in 500 cases of urological lithiasis as well as the incidence of these and the aforementioned compounds accordign to age and sexo Most of the cases are due to calcium oxalate, uric acid was founf as the second compound. Lithiasis frecuency is higher in persons between forty and sixty years and slighty bigger in males.Se ha realizado el estudio de la frecuencia de los componentes minerales en 500 casos de litiasis urológicas, así como la incidencia de éstas y los cita:los componentes de acuerdo con la edad y sexo. Se observa que la mayor parte de los casos se deben a oxalato cálcico, seguido de ácido úrico, siendo más frecuentes las litiasis entre los 40 y 60 años, presentándose en número ligeramente mayor en el sexo masculino

    Stability metrics for multi-source biomedical data based on simplicial projections from probability distribution distances

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    [EN] Biomedical data may be composed of individuals generated from distinct, meaningful sources. Due to possible contextual biases in the processes that generate data, there may exist an undesirable and unexpected variability among the probability distribution functions (PDFs) of the source subsamples, which, when uncontrolled, may lead to inaccurate or unreproducible research results. Classical statistical methods may have difficulties to undercover such variabilities when dealing with multi-modal, multi-type, multi-variate data. This work proposes two metrics for the analysis of stability among multiple data sources, robust to the aforementioned conditions, and defined in the context of data quality assessment. Specifically, a global probabilistic deviation (GPD) and a source probabilistic outlyingness (SPO) metrics are proposed. The first provides a bounded degree of the global multi-source variability, designed as an estimator equivalent to the notion of normalized standard deviation of PDFs. The second provides a bounded degree of the dissimilarity of each source to a latent central distribution. The metrics are based on the projection of a simplex geometrical structure constructed from the Jensen-Shannon distances among the sources PDFs. The metrics have been evaluated and demonstrated their correct behaviour on a simulated benchmark and with real multi-source biomedical data using the UCI Heart Disease dataset. The biomedical data quality assessment based on the proposed stability metrics may improve the efficiency and effectiveness of biomedical data exploitation and research.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by own IBIME funds under the UPV project Servicio de evaluacion y rating de la calidad de repositorios de datos biomedicos [UPV-2014-872] and the EU FP7 Project Help4Mood - A Computational Distributed System to Support the Treatment of Patients with Major Depression [ICT-248765].Sáez Silvestre, C.; Robles Viejo, M.; García Gómez, JM. (2014). Stability metrics for multi-source biomedical data based on simplicial projections from probability distribution distances. Statistical Methods in Medical Research. 1-25. https://doi.org/10.1177/0962280214545122S12

    Local detection of microvessels in IDH-wildtype glioblastoma using relative cerebral blood volume: an imaging marker useful for astrocytoma grade 4 classification

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    [EN] Background The microvessels area (MVA), derived from microvascular proliferation, is a biomarker useful for high-grade glioma classification. Nevertheless, its measurement is costly, labor-intense, and invasive. Finding radiologic correlations with MVA could provide a complementary non-invasive approach without an extra cost and labor intensity and from the first stage. This study aims to correlate imaging markers, such as relative cerebral blood volume (rCBV), and local MVA in IDH-wildtype glioblastoma, and to propose this imaging marker as useful for astrocytoma grade 4 classification. Methods Data from 73 tissue blocks belonging to 17 IDH-wildtype glioblastomas and 7 blocks from 2 IDH-mutant astrocytomas were compiled from the Ivy GAP database. MRI processing and rCBV quantification were carried out using ONCOhabitats methodology. Histologic and MRI co-registration was done manually with experts' supervision, achieving an accuracy of 88.8% of overlay. Spearman's correlation was used to analyze the association between rCBV and microvessel area. Mann-Whitney test was used to study differences of rCBV between blocks with presence or absence of microvessels in IDH-wildtype glioblastoma, as well as to find differences with IDH-mutant astrocytoma samples. Results Significant positive correlations were found between rCBV and microvessel area in the IDH-wildtype blocks (p < 0.001), as well as significant differences in rCBV were found between blocks with microvascular proliferation and blocks without it (p < 0.0001). In addition, significant differences in rCBV were found between IDH-wildtype glioblastoma and IDH-mutant astrocytoma samples, being 2-2.5 times higher rCBV values in IDH-wildtype glioblastoma samples. Conclusions The proposed rCBV marker, calculated from diagnostic MRIs, can detect in IDH-wildtype glioblastoma those regions with microvessels from those without it, and it is significantly correlated with local microvessels area. In addition, the proposed rCBV marker can differentiate the IDH mutation status, providing a complementary non-invasive method for high-grade glioma classification.This work was funded by grants from the National Plan for Scientific and Technical Research and Innovation 2017-2020, No. PID2019-104978RB-I00) (JMGG); H2020-SC1-2016-CNECT Project (No. 727560) (JMGG), and H2020SC1-BHC-2018-2020 (No. 825750) (JMGG). M.A.T was supported by DPI201680054-R (Programa Estatal de Promocion del Talento y su Empleabilidad en I + D + i). EFG was supported by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 844646. The funding body played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.Álvarez-Torres, MDM.; Fuster García, E.; Juan-Albarracín, J.; Reynes, G.; Aparici-Robles, F.; Ferrer Lozano, J.; Garcia-Gomez, JM. (2022). Local detection of microvessels in IDH-wildtype glioblastoma using relative cerebral blood volume: an imaging marker useful for astrocytoma grade 4 classification. BMC Cancer. 22(1):1-13. https://doi.org/10.1186/s12885-021-09117-411322
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