909 research outputs found
Tolerance assessment of the aquatic invasive snail Potamopyrgus antipodarum to different post-dispersive conditions: implications for its invasive success
The New Zealand mudsnail (NZMS) Potamopyrgus antipodarum (Gray, 1843) (Tateidae, Mollusca) is a successful invasive species able to alter the functioning of the invaded ecosystems. However, to arrive and establish in new aquatic ecosystems, this snail must survive to the overland translocation through aerial exposure and must tolerate the new physical and chemical conditions of the recipient ecosystem. In this study, we simulated different conditions for the NZMS invasion by combining two air exposure treatments (0 and 20 h) with different physical and chemical conditions of the rehydration water (low and normal water temperatures and normal and high water conductivities). Mortality, behavior and neonate production were compared across treatments. Air exposure caused a high percentage of mortality but survivors tolerated the subsequent abiotic conditions. Low temperatures and high conductivities altered the behavior of adult snails, increasing significantly their reaction time (i.e. time to start normal movement). This may have negative consequences for the survival of this species under natural conditions. Finally, these conditions did not affect significantly the production of neonates. These results supported that the surviving NZMS to a brief period of air exposure possess the ability to acclimate to contrasting abiotic conditions with a potential establishment of new populations and that survivors can reproduce in different abiotic conditions after an air exposure period
Effects of litter mixing on litter decomposition and soilproperties along simulated invasion gradients of non-nativetrees
Aims Plant invasions generally lead to mixtures betweennative and non-native litter. We assess the interactionsbetween leaf litters from two invasive non-native trees(Robinia pseudoacia or Ailanthus altissima) and the nativePopulus alba on litter decomposition, nutrient releaseand soil properties along two gradients of invasion.Methods Microcosms with field-collected soil coveredby varying proportions of native and non-native littersimulated the two invasion gradients. We assessed theproportion of remaining litter mass and nutrient mass(N, P, C), and soil C, N-NO3−, total N, and pH, fivetimes throughout a period of 11 months. Observedvalues were compared to the expected values on theassumption of no interactions.Results Litter mass and C mass decayed slower inRobinia and faster in Ailanthus than in Populus. Thethree species immobilized N and P. Soil properties didnot differ across pure litters. Both litter mixture gradientsshowed additive or antagonistic interactions onlitter decomposition, whereas N and P mass were equalor higher than expected. The proportion of non-nativelitter in the mixture had non-linear effects on mostvariables, suggesting that the impact of these nonnativetrees on litter decay levels off or even declinesas they become more abundant.Conclusion The impacts of Ailanthus and Robinia litteron soil processes should not be derived from singlespecies experiments, both due to non-additive effectsand to non-linear responses to litter abundance.Ministerio de Ciencia, Innovación y UniversidadesComunidad de Madri
School and Family Environment is Positively Associated with Extracurricular Physical Activity Practice among 8 to 16 Years Old School Boys and Girls
Extracurricular physical activity in children and adolescents can help achieve compliance with the World Health Organization (WHO) recommendations for physical activity. The purpose of this study was to evaluate factors in school and family environments of children and adolescents in Spain that could be related to the practice of extracurricular physical activity. Multistage random cluster sampling was conducted to include 128 schools with the participation of 10,096 students between the ages of 7 and 16. Participants completed the survey of sports habits designed by the National Sports Council. The results revealed a higher participation in extracurricular sports activities among boys (OR: 1.67 (1.5–1.9)) and students in primary education (up to 12 years old) (OR: 1.8 (1.7–2.0)). Likewise, a statistically significant relationship (p < 0.005) was observed between families where another family member practiced sports and lower number of screen time hours, improved academic performance, and better self-perceived health. Participation of children and adolescents in extracurricular sports activities seems to be associated with their immediate environment. It is therefore essential to emphasize the importance of establishing physical activity habits from an early age in family and school environments
Searching for predictors of the variability of impacts caused by non-native trees on regulating ecosystem services worldwide
Humans have introduced non-native trees (NNT) all over the world to take advantage of the plethora of benefits they provide. However, depending on the context, NNT may present a diverse range of effects on ecosystem services (ES), from benefits to drawbacks, which may hinder the development of policies for these species. Unfortunately, the attempts so far to understand the impacts of NNT on ES only explained a low proportion of their variation. Here we analyze the variation in impacts of NNT on regulating ecosystem services (RES) by using a global database, which covers the effect size of multiple NNT species on six RES (climate regulation, soil erosion regulation, soil fertility, soil formation, hydrological cycle regulation, and fire protection). We used a wide range of predictors to account for the context-dependency of impacts distributed in five groups: the RES type, functional traits of both the NNT and the dominant NT of the recipient ecosystem, phylogenetic and functional distances between NNT and NT, climatic context, and human population characteristics. Using boosted regression trees and regression trees, we found that the most influential predictors of NNT impacts on RES were annual mean temperatures and precipitation seasonality, followed by the type of RES, human population density, and NNT height. In regions with warm temperatures and low seasonality, NNT tended to increase RES. NNT impacts were greater in densely populated regions. Smaller NNT exerted greater positive impacts on climate regulation and soil erosion regulation in tropical regions than in other climates. We highlight that benign climates and high population density exacerbate the effects of NNT on RES, and that soil fertility is the most consistently affected RES. Knowledge of the factors that modulate NNT impacts can help to predict their potential effects on RES in different parts of the world and at various environmental setting
Chitosan-based hydrogels obtained via photoinitiated click polymer IPN reaction
Chitosan (CTS) is a polysaccharide with a wide variety of applications in the biomedical field, owing to its outstanding disinfectant properties, biocompatibility and biodegradability, but with limited mechanical properties. The proposed strategy to improve CTS-based hydrogel properties in this study is the formation of a semi-interpenetrating polymer network (semi-IPN). In this way, a photo-initiated radical click reaction was proposed to obtain a synthetic polymer, whose components were included in a CTS solution, resulting in the semi-IPN network after UV illumination. Different crosslinking degrees (CD) and CTS/polymer ratios were evaluated through rheological characterization, along with an assessment of both variables based on an experimental model design, obtaining that, for every CTS/polymer ratio, intermediate values of CD (8 %) offered the best rheological properties. In addition, chemical and microstructural characterization were carried out for selected hydrogels, obtaining consistent results according to rheological characterization, as the 1/1 CTS/polymer ratio with CD 8 % hydrogel displayed the most homogeneous pore size and distribution, consequently leading to the best rheological performance.This study was financially supported by MCIN/AEI/10.13039/5 01100011033/FEDER, UE, through the project PID2021-
124294OB-C21. The authors gratefully acknowledge their financial support. This work was also possible thanks to the postdoctoral contract of Víctor M. Pérez Puyana from the ‘‘Contratación de Personal Investigador Doctor” supported by the European Social Fund and Junta de Andalucía (PAIDI DOCTOR – Convocatoria 2019–2020, DOC_00586)
Aplicación de la semejanza en mecánica de fluidos: concurso de diseño y lanzamiento de paracaídas
[SPA] Se trata de construir paracaídas a escala de manera que pueda transportar un peso determinado y lo deposite en el suelo sin que se rompa. Se presenta una metodología de trabajo en grupos formados por tres alumnos basada en el diseño de paracaídas. Los estudiantes llevan a cabo cálculos teóricos para estimar el tamaño del paracaídas para que lleve a cabo la misión encomendada. Al finalizar el plazo de ejecución del proyecto se realiza un concurso en el que cada grupo lanza su paracaídas. Esta metodología docente se evaluó mediante una encuesta proporcionada a los alumnos cuyos resultados se muestran en la parte final del artículo.[ENG] This paper presents an active methodology of group work based on the design of parachutes. For this purpose small groups of 3 students are constituted. The students have to design a parachute to reach a specific task. At the end of the implementation period of the project we carry out a competition where each group launches its parachute. This teaching methodology was evaluated by means of a survey that was provided to the students. The results of the survey are shown at the end of the paper.Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci
Prevalencia de factores de riesgo cardiovascular en la población usuaria en el primer nivel de atención del sistema de salud salvadoreño
RESUMEN: Las enfermedades cardiovasculares son un grupo de desórdenes del corazón y de los vasos sanguíneos que tras varios años de investigaciones se ha determinado que están influenciadas por factores modificables y no modificables del individuo, por lo que entre más factores presentes cada uno, se eleva el riesgo de desarrollar una patología cardiovascular. En la actualidad siguen siendo la principal causa de muerte, discapacidad, y gasto médico a nivel mundial. Objetivo: Determinar los factores de riesgo cardiovascular en la población usuaria del primer nivel de atención del sistema de salud salvadoreño. Metodología: Se llevó a cabo un estudio descriptivo, transversal y retrospectivo. La población estuvo conformada por los usuarios que consultaron en el año 2019, cuyas edades oscilaron entre 40 a 59 años, pertenecientes a las unidades de primer nivel. Se realizó un muestreo probabilístico aleatorio simple, en el que la muestra se constituyó de 365 expedientes clínicos de los usuarios antes mencionados. Los datos fueron recolectados mediante técnica documental escrita, y el instrumento fue una guía de revisión online de expediente clínico, y se valoró el riesgo global mediante la escala de riesgo cardiovascular de la Organización Mundial de la Salud para la región de las américas. Principales conclusiones: Los factores de riesgo cardiovascular más frecuentes en los usuarios del primer nivel de atención en salud salvadoreño son sedentarismo, obesidad, y enfermedades preexistentes como hipertensión arterial y diabetes mellitus tipo 2, encontrándose que son mujeres quienes más frecuentemente consultan, y en quienes se encontraron estos factores de riesgo. Se evidenció que no se realiza tamizaje adecuado, investigando cifras de colesterol, sus fracciones, triglicéridos, a pesar que la mayoría de los usuarios tienen sobrepeso y obesidad. Pese a lo anterior, se estimó el riesgo cardiovascular a diez años de sufrir un evento cardiovascular grave, el cual fue menor del 10 por ciento en la población estudiada.
ABSTRACT: Cardiovascular diseases are a group of disorders of the heart and blood vessels that after several years of research it has been determined that they are influenced by modifiable and non-modifiable factors of the individual, so that the more factors present each one, the risk rises to develop a cardiovascular disease. Today they remain the leading cause of death, disability, and medical expense worldwide. Objective: To determine the cardiovascular risk factors in the user population of the first level of care of the Salvadoran health system. Methodology: A descriptive, cross-sectional and retrospective study was carried out. The population was made up of users who consulted in 2019, age groups ranged from 40 to 59 years old, belonging to the first level units. A simple random probability sampling was carried out, in which the sample was based on 365 clinical records of the aforementioned users. The data were collected using a written documentary technique, and the instrument was an online review guide for the clinical record, and the global risk was assessed using the World Health Organization cardiovascular risk scale for the Americas region. Main conclusions: The most frequent cardiovascular risk factors in users of the first level of Salvadoran health care are sedentary lifestyle, obesity, and pre-existing diseases such as hypertension and type 2 diabetes mellitus, finding that it is women who most frequently consult, and in whom these risk factors were found. It was evidenced that adequate screening is not carried out, investigating cholesterol levels, its fractions, and triglycerides, despite the fact that the majority of users are overweight and obese. Despite the above, the 10-year cardiovascular risk of suffering a serious cardiovascular event was estimated, which was less than 10 percent in the population studied
Interleukin 18 maintains a long-standing inflammation in coeliac disease patients
Producción CientíficaDietary gluten induces an early response in the intestine of coeliac disease
patients (CD), within a few hours, and this is driven by high levels of proinflammatory
cytokines, including IFNg and IL-15, as has been thoroughly
shown by gluten stimulation of biopsy explants. Our aim was to identify the
immune mediators involved in the long-standing inflammation in untreated
CD patients at diagnosis. mRNA and protein levels of TNFa, IL-12(p35),
IL-12(p40), IL-15, IL-18 and IL-23(p19) were quantified in biopsies from
active CD patients, CD patients on a gluten-free diet (GFD), healthy controls,
and patients with non-CD inflammation and mild histological changes in the
intestine. Biopsies from CD patients on a GFD were also stimulated in vitro
with gliadin, and protein expression of IL-15 and IL-18 was analysed. Levels of
IL-12 and IL-23 mRNA are nearly absent, and TNFa levels remain unchanged
among different groups. Both the active and inactive forms of IL-18 protein
have been found in all samples from active CD, and protein expression was
only localized within the crypts. Levels of IL-15 mRNA remain unchanged,
and protein expression, localized within the lamina propria, is found in a
small number of samples. In vitro stimulation with gluten induces the expression
of IL-15 and IL-18. In active CD, the early response following gluten
intake characterized by high IFNg levels is driven by IL-18, and probably
IL-15, and this alternates with periods of long-standing inflammation with
moderate IFNg levels, maintained by IL-18 alone
Diseño de un sistema cctv para el monitoreo de los buses articulados de transmilenio usando una red wimax
The Closed Circuit Television (CCTV) system provides an effective tool to increase security within the public bus mass transit system of Bogotá’s, Transmilenio; because it provides accessibility to monitor the articulated buses through a combined architecture video surveillance between analog and network, using rolling out a WiMAX network dedicated to this service. This proposal called TmTV, is based on the client-server architecture, mainstay of distributed systems; since all computers and devices on this system operate and deployed transparently in the Central Monitoring Station. El sistema de Circuito Cerrado de Televisión (CCTV) provee una herramienta eficaz para incrementar la seguridad al interior de los buses del sistema público de transporte de la ciudad de Bogotá, Transmilenio; debido a que provee la accesibilidad para monitorear los buses articulados a través de una arquitectura de video vigilancia combinada entre análoga y red; utilizando para ello el despliegue de una Red WiMAX dedicada para este servicio. Esta propuesta denominada TmTV, se basa en la arquitectura cliente - servidor, pilar de los sistemas distribuidos, dado que todos los equipos y dispositivos del sistema operan y se despliegan de manera transparente en la estación Central de Monitoreo.
Is it true coeliacs do not digest gliadin ?. Degradation pattern of gliadin in coeliac disease small intestinal mucosa
Prolyl-endopeptidase supplementation has
been proposed to favour gliadin degradation
as an alternative treatment for coeliac
disease (CD), although the real usefulness
of this therapy in vivo is still under discussion.
1 However, our data point to alternative
treatments aiming to modify the intestinal
microbiota in patients with CD by the use
of probiotics and/or prebiotics. We propose
that the induction of gliadin proteolysis in
the human gut might not be the solution
but the origin of CD
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