3,820 research outputs found

    Microbial Community Structure and Metabolic Networks in Polar Glaciers

    Get PDF
    Polar glaciers are inhabited by numerous microorganisms including representatives of bacteria, archaea, microeukaryotes, and viruses. Low temperature is a main factor when considering polar glaciers as extreme environments. However, desiccation, low nutrients availability, ultraviolet irradiation, and photoreactive chemistry do also significantly influence their challenging life. Glaciers are highly selective and confined habitats, which make them favorable environments for adaptation and speciation. Depending on the glacier area studied, microorganisms establish a vertical food chain, from the surface photosynthesizers in upper illuminated layers to chemoautotrophs and heterotrophs confined to the inner part. These regions are rich not only in biodiversity but also in new mechanisms of adaptation to the environment, since selection acts with a particular intensity. Glaciers are retreating in many areas of the world due to global warming. When glaciers have ultimately withdrawn, microorganisms play a main role, carrying out key processes in the development of soil and facilitating plant colonization. These features make them unique and interesting for the study and protection of the biological heritage. Metagenomics have allowed a deeper understanding of microbial ecology and function of polar glacier microbial communities. In this review, we present a complete analysis of the microbial diversity in these ecosystems and include a thorough overview of the metabolic potentials and biogeochemical cycles in polar glacier habitats

    Adsorption of humic substances on ferrihydrite affects its use as iron source by plants

    Get PDF
    Poorly crystalline Fe oxides are sources of Fe to plants. The adsorption of humic substances (HS) on these oxides alters its reactivity and stability in soils, and thus may affect Fe mobilization and uptake by plants from these compounds. This work aimed at studying how the adsorption of HS on Fe oxides affects its use as Fe source by two plant species with different Fe acquisition strategies, white lupin (Strategy I) and wheat (Strategy II). To this end, two completely randomized experiments, one with each plant, were carried out using a calcareous growing media and involving increasing amounts of HS adsorbed on ferrihydrite (0, 16, 60, and 97 mg C g–1) which was used as Fe source. The highest HS rate was the only treatment that significantly increased Fe uptake in wheat relative to control without HS. This was related to a decreased concentration of Fe in poorly crystalline oxides in the growing media. On the contrary, HS did not affect significantly Fe uptake by lupin. However, in this crop, the highest HS rate decreased the concentration of Fe in oxides relative to the lowest HS rate, without significant differences with other treatments. Thus, the effect of adsorbed HS on Fe uptake differed in two plants with different Fe acquisition strategies. The increased Fe uptake in wheat at the highest HS rate can be explained at least in part by an increased Fe mobilization from oxides by plant roots. These findings provide new insights on the role of soil organic matter on plant Fe nutrition

    Plataforma educativa virtual “Nyquist”

    Get PDF
    Este proyecto pretende diseñar e implementar una plataforma educativa virtual que le permita a la Universidad Tecnológica de Pereira ampliar su área de cobertura sin necesidad de ampliar sus instalaciones físicas. Está planteado en dos fases que pueden ser desarrolladas en paralelo, ambas importantes para la culminación exitosa del proyecto: análisis, diseño e implementación de un aplicativo que permite la realización de clases tradicionales a través de redes de datos de amplia difusión como por ejemplo internet. Además propone un modelo pedagógico que busca que todo el contenido de las clases sea asimilado por los estudiantes y que la adopción de dicha plataforma sea lo menos traumática posible

    Characterization of micromobility crashes in Spain (2016-2020)

    Get PDF
    Micromobility has a direct impact on the urban area, since it tries to make cities more liveable, o:ffering an alternative transport option that contributes to reduce air and noise pollution. Additionally, it promotes intennodality, promotes money savings, reduces parking space and helps to avoid road congestion in cities that have their own lanes for the use of micromobility vehicles such as bicycles, stand-up e-scooters (escooters) and other personal mobility vehicles (PMVs). In Spain, micromobility has significantly increased in recent years, through the increase in the supply and demand for bicycles and other PMVs, mainly e-scooters. There are many reasons that have motivated users to prioritize the bicycle and the other PMVs over other means of tra.nsport. In addition to the growing concern for health and the environment, the COVID-19 pandemic has also driven the growth in the use ofthe different PMVs in 2020. Accordmg to data from Global Public Transport Report, published by the mobility application Moovit, 31 % of Spanianis have used bicycles, scooters or e-scooters in 2020, increasing their use by 7% since 2019. However, in parallel and because of the increase in PMVs exposure, the number of crashes involving users of these vehicles has also increased in recent years. For this reason, among road safety researchers, interest and concern for the study of this kind of crashes have also increased The aim of this research is to characterize the crashes in Spain in which at least one PMV (bicycle, e-scooter or other PMV) is involved between the years 2016 and 2020

    Development of lactoferrin-loaded liposomes for the management of dry eye disease and ocular inflammation

    Get PDF
    Dry eye disease (DED) is a high prevalent multifactorial disease characterized by a lack of homeostasis of the tear film which causes ocular surface inflammation, soreness, and visual disturbance. Conventional ophthalmic treatments present limitations such as low bioavailability and side effects. Lactoferrin (LF) constitutes a promising therapeutic tool, but its poor aqueous stability and high nasolacrimal duct drainage hinder its potential efficacy. In this study, we incorporate lactoferrin into hyaluronic acid coated liposomes by the lipid film method, followed by high pressure homogenization. Pharmacokinetic and pharmacodynamic profiles were evaluated in vitro and ex vivo. Cytotoxicity and ocular tolerance were assayed both in vitro and in vivo using New Zealand rabbits, as well as dry eye and anti-inflammatory treatments. LF loaded liposomes showed an average size of 90 nm, monomodal population, positive surface charge and a high molecular weight protein encapsulation of 53%. Biopharmaceutical behaviour was enhanced by the nanocarrier, and any cytotoxic effect was studied in human corneal epithelial cells. Developed liposomes revealed the ability to reverse dry eye symptoms and possess anti-inflammatory efficacy, without inducing ocular irritation. Hence, lactoferrin loaded liposomes could offer an innovative nanotechnological tool as suitable approach in the treatment of DED.FCT -Fundação para a Ciência e a Tecnologia(2017SGR1477)info:eu-repo/semantics/publishedVersio

    Ayotzinapa: Viejas luchas, nuevas formas

    Get PDF
    En el presente documento se brinda una breve crónica de lo acontecido cuando en septiembre de 2014, con la participación de elementos de la fuerza pública, se desapareció a 43 estudiantes de la Normal Rural Isidro Burgos de Ayotzinapa, Guerrero. Se da cuenta tanto de las inconsistencias de la verdad histórica presentada por el gobierno federal, como de la crisis de legitimidad que vive la actual administración que, si bien llegó con el apoyo de un porcentaje muy bajo del electorado, con el paso de los años ha visto disolver su popularidad. Por otro lado, siguiendo las ideas de Raul Zibechi y Ana Esther Ceceña se menciona que lo sucedido en Ayotzinapa debe ser visto como un emblema del capitalismo neoextractivista que aqueja nuestra región. En dicho sentido se hace énfasis a la agenda política y económica de la actual administración, con el objetivo de dar cuenta de una agudización de las contradicciones sociales, sobre todo en territorios rurales de nuestro país

    Mobile Usability: An Experiment to Check Whether Current Mobile Devices are Ready to Support Frames and iFrames

    Get PDF
    Frames have traditionally been identified as a usability issue in websites for computers. Literature points out that they may also be a problem for mobile websites but no studies have been carried out to prove it. Since mobile devices have changed a lot in recent years, it is necessary to check whether frames are still a problem for those devices. In this paper we have performed an experiment with twenty-two mobile devices, to test whether the content can be showed in their browsers, as well as their behavior with different configuration of frames and iframes and whether behavior of bookmarks and the back button is correct or not. The results show that frames and iframes should be avoided in mobile devices because they can cause many problems, which are explained in detail in this paper

    Multimodality Imaging of Chronic Ischemia

    Get PDF
    Although ischemic cardiomyopathy is commonly caused by chronic obstructive coronary disease, the mechanism of the cause is still under investigation. We present echocardiographic strain, magnetic resonance, and histology findings in a chronic ischemia model in preclinical study. This case illustrates the features of multimodality imaging in chronic obstructive coronary disease and gives us great insight into understanding the mechanism of ischemic cardiomyopathy

    A Cross-Sectional Study of Tobacco Advertising, Promotion, and Sponsorship in Airports across Europe and the United States

    Get PDF
    Altres ajuts: The work was supported by grant number 108594 from the Flight Attendant Medical Research Institute (FAMRI) to the Johns Hopkins FAMRI Center of Excellence. The funder had no role in the Int. J. Environ. Res. Public Health 2016, 13, 959 8 of 9 study design, collection, analysis or interpretation of data, writing of the report, nor in the decision to submit the paper for publication.Tobacco advertising, promotion, and sponsorship (TAPS) bans are effective and are increasingly being implemented in a number of venues and countries, yet the state of TAPS in airports and their effect on airport smoking behavior is unknown. The objective of this study was to evaluate the presence of TAPS in airports across Europe and the US, and to begin to examine the relationship between TAPS and smoking behaviors in airports. We used a cross-sectional study design to observe 21 airports in Europe (11) and the US (10). Data collectors observed points of sale for tobacco products, types of products sold, advertisements and promotions, and branding or logos that appeared in the airport. Tobacco products were sold in 95% of all airports, with significantly more sales in Europe than the US. Advertisements appeared mostly in post-security areas; however, airports with advertisements in pre-security areas had significantly more smokers observed outdoors than airports without advertisements in pre-security areas. Tobacco branding appeared in designated smoking rooms as well as on non-tobacco products in duty free shops. TAPS are widespread in airports in Europe and the US and might be associated with outdoor smoking, though further research is needed to better understand any relationship between the two. This study adds to a growing body of research on tobacco control in air transit and related issues. As smoke-free policies advance, they should include comprehensive TAPS bans that extend to airport facilities
    corecore