178 research outputs found
Unexplained hydrogen isotope offsets complicate the identification and quantification of tree water sources in a riparian forest
We investigated plant water sources of an emblematic refugial
population of Fagus sylvatica (L.) in the Ciron river gorges in south-western France using
stable water isotopes. It is generally assumed that no isotopic
fractionation occurs during root water uptake, so that the isotopic
composition of xylem water effectively reflects that of source water.
However, this assumption has been called into question by recent studies
that found that, at least at some dates during the growing season, plant
water did not reflect any mixture of the potential water sources. In this
context, highly resolved datasets covering a range of environmental
conditions could shed light on possible plant–soil fractionation processes
responsible for this phenomenon. In this study, the hydrogen (δ2H) and oxygen (δ18O) isotope compositions of all
potential tree water sources and xylem water were measured fortnightly over
an entire growing season. Using a Bayesian isotope mixing model (MixSIAR),
we then quantified the relative contribution of water sources for F. sylvatica and
Quercus robur (L.) trees. Based on δ18O data alone, both species used a mix
of top and deep soil water over the season, with Q. robur using deeper soil water
than F. sylvatica. The contribution of stream water appeared to be marginal despite the
proximity of the trees to the stream, as already reported for other riparian
forests. Xylem water δ18O could always be interpreted as a
mixture of deep and shallow soil waters, but the δ2H of xylem
water was often more depleted than the considered water sources. We argue
that an isotopic fractionation in the unsaturated zone and/or within the
plant tissues could underlie this unexpected relatively depleted δ2H of xylem water, as already observed in halophytic and xerophytic
species. By means of a sensitivity analysis, we found that the estimation of
plant water sources using mixing models was strongly affected by this
δ2H depletion. A better understanding of what causes this
isotopic separation between xylem and source water is urgently needed.</p
Reflexiones sobre los retos y oportunidades de la educación híbrida
3er Coloquio Fortalecimiento de los Colectivos de Docencia.Reconociendo que esta educación tiene características y metodologías pedagógicas diferentes a las presenciales, de cara al futuro hay que pensar en un formato híbrido que combine la noción presencial y la noción virtual de manera funcional. La modalidad actual funciona como respuesta a una emergencia, pero hay que desarrollar estrategias que sostengan este nuevo modelo en el mediano plazo. Integrantes del Colectivo de Docencia de Diseño Industrial del Departamento de Evaluación, nos reunimos en conferencia vía zoom, para discurrir sobre el tema. Algunas de las reflexiones se integran a la presentación en forma directa con el fin de evitar cualquier mala interpretación relacionada a las propuestas y sugerencias
Understanding The Correlation Of Libs And Acoustic Measurements Of Rocks And Soils Found In The Traverse Of The Perseverance Rover Across The Jezero Crater, Mars
The SuperCam instrument of the NASA MARS 2020 Perseverance rover combines a suite of atomic and molecular spectroscopies intended for an extensive description of rocks, soils and minerals in the surroundings of the landing site of the mission – the Jezero crater. The microphone installed on the SuperCam instrument allows the acquisition of acoustic signals resulting from the expansion of laser-induced plasmas towards the atmosphere. Apart from being affected by the propagation characteristics of the Mars atmosphere, the acoustic signal has an additional component related to the properties of the target including surface morphology, hardness, deformation parameters, and elasticity, among others. This information is currently being investigated as a complementary resource for characterization of the ablated material and may well supplement the LIBS data gathered from coincident laser shots. This talk will present SuperCam acoustic data of rocks and minerals found in the traverse of the Perseverance rover and will discuss its correlation with LIBS spectra.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
LIBS and Acoustic Measurements of Rocks and Regolith Found in the Traverse of the Perseverance Rover Across the Jezero Crater, Mars
The SuperCam instrument of the NASA MARS 2020 Perseverance rover combines a suite of atomic and molecular
spectroscopies intended for an extensive description of rocks, soils and minerals in the surroundings of the landing site
of the mission – the Jezero crater. The microphone installed on the SuperCam instrument allows the acquisition of acoustic
signals resulting from the expansion of laser-induced plasmas towards the atmosphere. Apart from being affected by the
propagation characteristics of the Mars atmosphere, the acoustic signal has an additional component related to the
properties of the target including surface morphology, hardness, deformation parameters, and elasticity, among others.
This information is currently being investigated as a complementary resource for characterization of the ablated material
and may well supplement the LIBS data gathered from coincident laser shots. This talk will present SuperCam acoustic
data of rocks and minerals found in the traverse of the Perseverance rover and will discuss its correlation with LIBS
spectra.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Genesis of a Fungal Non-Self Recognition Repertoire
Conspecific allorecognition, the ability for an organism to discriminate its own cells from those of another individual of the same species, has been developed by many organisms. Allorecognition specificities are determined by highly polymorphic genes. The processes by which this extreme polymorphism is generated remain largely unknown. Fungi are able to form heterokaryons by fusion of somatic cells, and somatic non self-recognition is controlled by heterokaryon incompatibility loci (het loci). Herein, we have analyzed the evolutionary features of the het-d and het-e fungal allorecognition genes. In these het genes, allorecognition specificity is determined by a polymorphic WD-repeat domain. We found that het-d and het-e belong to a large gene family with 10 members that all share the WD-repeat domain and show that repeats of all members of the family undergo concerted evolution. It follows that repeat units are constantly exchanged both within and between members of the gene family. As a consequence, high mutation supply in the repeat domain is ensured due to the high total copy number of repeats. We then show that in each repeat four residues located at the protein/protein interaction surface of the WD-repeat domain are under positive diversifying selection. Diversification of het-d and het-e is thus ensured by high mutation supply, followed by reshuffling of the repeats and positive selection for favourable variants. We also propose that RIP, a fungal specific hypermutation process acting specifically on repeated sequences might further enhance mutation supply. The combination of these evolutionary mechanisms constitutes an original process for generating extensive polymorphism at loci that require rapid diversification
Clinical manifestations, prevalence, risk factors, outcomes, transmission, diagnosis and treatment of COVID-19 in pregnancy and postpartum: a living systematic review protocol.
INTRODUCTION: Rapid, robust and continually updated evidence synthesis is required to inform management of COVID-19 in pregnant and postpartum women and to keep pace with the emerging evidence during the pandemic. METHODS AND ANALYSIS: We plan to undertake a living systematic review to assess the prevalence, clinical manifestations, risk factors, rates of maternal and perinatal complications, potential for mother-to-child transmission, accuracy of diagnostic tests and effectiveness of treatment for COVID-19 in pregnant and postpartum women (including after miscarriage or abortion). We will search Medline, Embase, WHO COVID-19 database, preprint servers, the China National Knowledge Infrastructure system and Wanfang databases from 1 December 2019. We will supplement our search with studies mapped by Cochrane Fertility and Gynaecology group, Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre), COVID-19 study repositories, reference lists and social media blogs. The search will be updated every week and not be restricted by language. We will include observational cohort (≥10 participants) and randomised studies reporting on prevalence of COVID-19 in pregnant and postpartum women, the rates of clinical manifestations and outcomes, risk factors in pregnant and postpartum women alone or in comparison with non-pregnant women with COVID-19 or pregnant women without COVID-19 and studies on tests and treatments for COVID-19. We will additionally include case reports and series with evidence on mother-to-child transmission of SARS-CoV-2 in utero, intrapartum or postpartum. We will appraise the quality of the included studies using appropriate tools to assess the risk of bias. At least two independent reviewers will undertake study selection, quality assessment and data extraction every 2 weeks. We will synthesise the findings using quantitative random effects meta-analysis and report OR or proportions with 95% CIs and prediction intervals. Case reports and series will be reported as qualitative narrative synthesis. Heterogeneity will be reported as I2 and τ2 statistics. ETHICS AND DISSEMINATION: Ethical approval is not required as this is a synthesis of primary data. Regular updates of the results will be published on a dedicated website (https://www.birmingham.ac.uk/research/who-collaborating-centre/pregcov/index.aspx) and disseminated through publications, social media and webinars. PROSPERO REGISTRATION NUMBER: CRD42020178076
Effects of Therapy in Oropharyngeal Dysphagia by Speech and Language Therapists: A Systematic Review
Medical and paramedical treatments should be evaluated according to current standards of evidence-based medicine. Evaluation of therapy in oropharyngeal dysphagia fits into this growing interest. A systematic review is given of the literature on the effects of therapy in oropharyngeal dysphagia carried out by speech therapists. Thus, the review excludes reports of surgical or pharmacological treatments. The literature search was performed using the electronic databases PubMed and Embase. All available inclusion dates up to November 2008 were used. The search was limited to English, German, French, Spanish, and Dutch publications. MESH terms were supplemented by using free-text words (for the period after January 2005). Fifty-nine studies were included. In general, statistically significant positive therapy effects were found. However, the number of papers was rather small. Moreover, diverse methodological problems were found in many of these studies. For most studies, the conclusions could not be generalized; comparison was hindered by the range of diagnoses, types of therapies, and evaluation techniques. Many questions remain about the effects of therapy in oropharyngeal dysphagia as performed by speech and language therapists. Although some positive significant outcome studies have been published, further research based on randomized controlled trials is needed
The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description
On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds
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