Estudio comparativo de la influencia de las fibras en la retracción de los morteros reciclados

Construction and demolition waste can be used as a substitution of natural aggregate in mortar and concrete elaboration. A poorer quality of recycled aggregates generally has negative impact on mortar properties. Shrinkage is one of the properties that experiences worse outcome due to the higher absorption of recycled aggregates. This research evaluates the potential shrinkage of mortars elaborated with recycled concrete aggregates both with and without fibres addition, as well as the relation between moisture loss and shrinkage caused by mortar drying process using a capacitive sensor of the authors’ own design. Two different mortar dosages 1:3 and 1:4 and three fiber types: polypropylene fiber, fiberglass and steel fiber, in different proportions were used. Obtained results show that the use of polypropylene fiber improves the recycled mortars performance against shrinkage in 0.2%. Moreover, a clear relation between dry shrinkage and moisture loss was observed.Los Residuos de Construcción y Demolición pueden ser usados como sustitución de los áridos naturales en la fabricación de morteros y hormigones. La peor calidad de los áridos reciclados empeora de manera general las propiedades de los morteros, siendo la retracción una de las que más se ve afectada. Esta investigación, estudia la retracción de los morteros elaborados con arena reciclada de hormigón con y sin adicción de fibras, así como la relación existente entre la perdida de humedad y la retracción por secado mediante un sensor capacitivo de diseño propio. Se han empleado dos dosificaciones diferentes 1:3 y 1:4 y tres tipos de fibras: polipropileno, vidrio y acero, en distintas proporciones. Los resultados muestran que la adición de fibras de polipropileno en un 0,2% mejora significativamente la retracción en los morteros reciclados. Además, se ha obtenido una relación clara entre la retracción por secado y la perdida de humedad

Granulomas en el prepucio de un equino causados por Micronema.

Se describe por primera vez en Colombia, un caso, no fatal, de parasitismo por Micronema sp, en un equino macho, causando una postitis granulamatosa. Se observaron numerosas larvas y nemátodos adultos, igualmente huevos hembrionados en cortes de tejidos coloreados con hematoxilina y eosina. Preparaciones de macerado de tejido granulomatoso, hicieron posible la observación detalladas del parásito para su identificación.Equinos-Caballo - caballo

Human prefoldin modulates co-transcriptional pre-mRNA splicing

Trabajo presentado en el IV Meeting RNALife, celebrado en Sevilla (España) del 12 al 13 de julio de 2021.Prefoldin is a heterohexameric complex conserved from archaea to humans that plays a co-chaperone role during the co-translational folding of actin and tubulin monomers. Additional functions of prefoldin have been described, including a positive contribution to transcription elongation and chromatin dynamics in yeast. Here we show that prefoldin perturbations provoked transcriptional alterations across the human genome. Severe pre-mRNA splicing defects were also detected, particularly after serum stimulation. We found impairment of co-transcriptional splicing during transcription elongation, which explains why the induction of long genes with a high number of introns was affected the most. We detected genome-wide prefoldin binding to transcribed genes and found that it correlated with the negative impact of prefoldin depletion on gene expression. Lack of prefoldin caused global decrease in Ser2 and Ser5 phosphorylation of the RNA polymerase II carboxy-terminal domain. It also reduced the recruitment of the CTD kinase CDK9 to transcribed genes, and the association of splicing factors PRP19 and U2AF65 to chromatin, which is known to depend on CTD phosphorylation. Altogether the reported results indicate that human prefoldin is able to act locally on the genome to modulate gene expression by influencing phosphorylation of elongating RNA polymerase II, and thereby regulating co-transcriptional splicing

Human prefoldin modulates co-transcriptional pre-mRNA splicing.

Prefoldin is a heterohexameric complex conserved from archaea to humans that plays a cochaperone role during the co-translational folding of actin and tubulin monomers. Additional functions of prefoldin have been described, including a positive contribution to transcription elongation and chromatin dynamics in yeast. Here we show that prefoldin perturbations provoked transcriptional alterations across the human genome. Severe pre-mRNA splicing defects were also detected, particularly after serum stimulation. We found impairment of co-transcriptional splicing during transcription elongation, which explains why the induction of long genes with a high number of introns was affected the most. We detected genome-wide prefoldin binding to transcribed genes and found that it correlated with the negative impact of prefoldin depletion on gene expression. Lack of prefoldin caused global decrease in Ser2 and Ser5 phosphorylation of the RNA polymerase II carboxy-terminal domain. It also reduced the recruitment of the CTD kinase CDK9 to transcribed genes, and the association of splicing factors PRP19 and U2AF65 to chromatin, which is known to depend on CTD phosphorylation. Altogether the reported results indicate that human prefoldin is able to act locally on the genome to modulate gene expression by influencing phosphorylation of elongating RNA polymerase II, and thereby regulating co-transcriptional splicing.Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación [BFU2016-77728-C3-1-P to S.C. and BFU2017-85420-R to J.C.R.] co-financed with European Union funds (FEDER); Andalusian Government [P12-BIO1938MO, BIO271, US-1256285 to S.C., BIO321 to J.C.R.]; Junta de Andalucía (to L.P.-B.). Funding for open access charge: Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación [BFU2016-77728-C3-1-P]

Jaguar Densities across Human-Dominated Landscapes in Colombia: The Contribution of Unprotected Areas to Long Term Conservation

Large carnivores such as jaguars (Panthera onca) are species of conservation concern because they are suffering population declines and are keystone species in their ecosystems. Their large area requirements imply that unprotected and ever-increasing agricultural regions can be important habitats as they allow connectivity and dispersal among core protected areas. Yet information on jaguar densities across unprotected landscapes it is still scarce and crucially needed to assist management and range-wide conservation strategies. Our study provides the first jaguar density estimates of Colombia in agricultural regions which included cattle ranching, the main land use in the country, and oil palm cultivation, an increasing land use across the Neotropics. We used camera trapping across two agricultural landscapes located in the Magdalena River valley and in the Colombian llanos (47–53 stations respectively; >2000 trap nights at both sites) and classic and spatially explicit capture-recapture models with the sex of individuals as a covariate. Density estimates were 2.52±0.46–3.15±1.08 adults/100 km2 in the Magdalena valley, whereas 1.12±0.13–2.19±0.99 adults/100 km2 in the Colombian llanos, depending on analysis used. We suggest that jaguars are able to live across unprotected human-use areas and co-exist with agricultural landscapes including oil-palm plantations if natural areas and riparian habitats persist in the landscape and hunting of both jaguar and prey is limited. In the face of an expanding agriculture across the tropics we recommend land-use planning, adequate incentives, regulations, and good agricultural practices for range-wide jaguar connectivity and survival

Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)

The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species

Metal release from contaminated estuarine sediment under pH changes in the marine environment

The contaminant release from estuarine sediment due to pH changes was investigated using a modified CEN/TS 14429 pH-dependence leaching test. The test is performed in the range of pH values of 0-14 using deionised water and seawater as leaching solutions. The experimental conditions mimic different circumstances of the marine environment due to the global acidification, carbon dioxide (CO2) leakages from carbon capture and sequestration technologies, and accidental chemical spills in seawater. Leaching test results using seawater as leaching solution show a better neutralisation capacity giving slightly lower metal leaching concentrations than when using deionised water. The contaminated sediment shows a low base-neutralisation capacity (BNCpH 12 = -0.44 eq/kg for deionised water and BNCpH 12 = -1.38 eq/kg for seawater) but a high acid-neutralisation capacity when using deionised water (ANCpH 4 = 3.58 eq/ kg) and seawater (ANCpH 4 = 3.97 eq/kg). Experimental results are modelled with the Visual MINTEQ geochemical software to predict metal release from sediment using both leaching liquids. Surface adsorption to iron- and aluminium- (hydr)oxides was applied for all studied elements. The consideration of the metal-organic matter binding through the NICA-Donnan model and Stockholm Humic Model for lead and copper, respectively, improves the former metal release prediction. Modelled curves can be useful for the environmental impact assessment of seawater acidification due to its match with the experimental values.This work was supported by the Spanish Ministry of Economy and Competitiveness, Project No. CTM 2011-28437-C02-01, ERDF included. M. C. Martı´n-Torre was funded by the Spanish Ministry of Economy and Competitiveness by means of FPI. Fellowship No. BES-2012-053816

Physiological response of chickpea (Cicer arietinum L.) in symbiosis with arbuscular mycorrhizal fungi under salinity conditions

Objective: The effect of salinity by NaCl based on physiological variables of chickpea plants was evaluated with the use of native strains of arbuscular mycorrhizal fungi Glomus cubensis and Rizoglomus irregulare during the pre-flowering phenophase. Design/methodology/approach: The research was carried out under controlled environmental conditions, using as an experimental model the chickpea variety N-29, obtained at INIFAT, Cuba. The treatments consist of the combination of three salinity levels: 25, 50 and 75 mM of NaCl and the respective control (Source of variation A) and two strains of AMFs (source of variation B) for a total of 12 treatments with six repetitions. Treatments were distributed under a completely randomized experimental design. The variables evaluated were: number of green and dry leaves, biomass by organs (leaves, stem, root), net assimilation rate (TAN), relative growth rate (TCR) and leaf area ratio (RAF). Results: Green leaves, TAN and leaf and root biomass were the variables with the highest response in the 50 mM NaCl + R. irregulare treatment, with an average increase of 15% compared to the rest of the treatments. Limitations on study/implications: There is a decrease in the variables evaluated due to the salinity effect, however, chickpea plants subjected to 50 mM NaCl inoculated with R. irregulare were less affected by saline stress. Findings/conclusions: It was also found that the R. irregulare strain contributed more than G. cubense to mitigating the adverse effects of the salinity factor.Objective. Evaluate the effect of salinity due to NaCl on physiological variables of chickpea plants using native strains of arbuscular mycorrhizal fungi (AMF) Glomus cubensis and Rhizoglomus irregulare during the pre-flowering stage. Design/methodology/approach. The research was carried out under controlled weather conditions using the chickpea variety N-29 as an experimental model. The treatments consisted on the combination of four salinity levels: 0, 25, 50 and 75 mM NaCl (variation source A) and AMF (variation source B) in three levels. In total there were 12 treatments with six repetitions, which were distributed in a completely randomized experimental design. The evaluated variables were number of green and dry leaves, dry biomass per organ (leaves, root and stem), net assimilation rate (NAR), relative growth rate (RGR) and leaf area ratio (LAR). Results. The green leaves, the NAR and the dry biomass from roots and leaves, were the variables with the greatest response in the 50 mM NaCl + R. irregulare treatment, with an average increase of 15% with respect to the rest of the treatments. Limitations/implications. A decrease on the evaluated variables was observed due to the salinity effect; however, chickpea plants subjected to NaCl 50 mM inoculated with R. irregulare were less affected by salt stress. Findings/conclusions. The R. irregulare strain was found to contribute more than the G. cubensis to the mitigation of the adverse effects from the salinity factor