An explanation for the isotopic offset between soil and stem water in a temperate tree species

A growing number of field studies report isotopic offsets between stem water and its potential sources that prevent the unambiguous identification of plant water origin using water isotopes. We explored the causes of this isotopic offset by conducting a controlled experiment on the temperate tree species Fagus sylvatica. We measured d2H and d18O of soil and stem water from potted saplings growing on three soil substrates and subjected to two watering regimes. Regardless of substrate, soil and stem water d2H were similar only near permanent wilting point. Under moister conditions, stem water d2H was 11 ± 3 more negative than soil water d2H, coherent with field studies. Under drier conditions, stem water d2H became progressively more enriched than soil water d2H. Although stem water d18O broadly reflected that of soil water, soil stem d2H and d18O differences were correlated (r = 0.76) and increased with transpiration rates indicated by proxies. Soil stem isotopic offsets are more likely to be caused by water isotope heterogeneities within the soil pore and stem tissues, which would be masked under drier conditions as a result of evaporative enrichment, than by fractionation under root water uptake. Our results challenge our current understanding of isotopic signals in the soil plant continuum. © 2020 The Authors. New Phytologist © 2020 New Phytologist TrustThis work was supported by the French national programme EC2CO-Biohefect (RootWater), the French national research agency (projects Hydrobeech, Climbeech and Micromic within the Cluster of Excellence COTE with grant agreement ANR-10-LABX-45; project ORCA with grant agreement ANR-13-BS06-0005-01), the European Research Council (ERC) under the EU Seventh Framework Program (FP7/2007-2013, with grant agreement no. 338264, awarded to LW) and the Aquitaine Region (project Athene with grant agreement 2016-1R20301-00007218). AB also acknowledges an IdEx Bordeaux postdoctoral fellowship from the Universite de Bordeaux (contract no. 22001162)

Effect of a gum-based thickener on the safety of swallowing in patients with poststroke oropharyngeal dysphagia

Altres ajuts: This work has been supported by Danone Nutricia Research, Fundació Salut del Consorci Sanitari del Maresme, Furega (Fundació per a la Recerca en Gastroenterologia) and Centro de Investigación en Red en Enfermedades Hepáticas y Digestivas (CIBERehd).Background: Increasing viscosity with thickening agents is a valid therapeutic strategy for oropharyngeal dysphagia (OD). To assess the therapeutic effect of a xanthan gum-based thickener (Nutilis Clear) at six viscosities compared with thin liquid in poststroke OD (PSOD) patients. Methods: A total of 120 patients with PSOD were studied in this controlled, multiple-dose, fixed-order, and single-blind study using videofluoroscopy (VFSS). A series of boluses of 10 mL thin liquid and 2000, 1400, 800, 450, 250, and 150 mPa s viscosities were given in duplicate, interrupted in case of aspiration. We assessed the safety and efficacy of swallow and the kinematics of the swallow response. Key Results: A total of 41.2% patients had safe swallow at thin liquid which significantly increased for all viscosities from 71.9% at 150 mPa s to 95.6% at 1400 mPa s (P <.001). PAS score (3.7 ± 2.3) at thin liquid was also reduced by increasing bolus viscosity (P <.001). The prevalence of patients with aspiration at thin liquid was 17.5% and decreased at all viscosities (P <.01), except at 150 mPa s. Increasing viscosity shortened time to laryngeal vestibule closure (LVC) at all viscosities (P <.01) and reduced bolus velocity at ≥450 mPa s (P <.05). The prevalence of patients with pharyngeal residue at each viscosity 37.7%-44.7% was similar to that at thin liquid (41.2%). Conclusions and Inferences: The prevalence of unsafe swallow with thin liquids is very high in PSOD. Increasing shear bolus viscosity with this xanthan gum-based thickener significantly increased the safety of swallow in patients with PSOD in a viscosity-dependent manner without increasing the prevalence of pharyngeal residue

New insights to predict seminal quality in young Limousine bulls (póster)

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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

The university library in teacher education: use of electronic and digital resources in scientific research

Analisa a utilização de recursos eletrônicos e digitais na formação de professores contextualizada em três bibliotecas universitárias: a Universidade Federal do Rio Grande do Sul, a Pontifícia Universidade Católica do Estado do Rio Grande do Sul e a Universidade de Passo Fundo. As interrelações entre cultura e educação, e a capacidade dos sujeitos entenderem e se adequarem à nova cultura emergente, ocorrem por meio de plataformas digitais e da virtualização de informações. Busca-se compreender se os recursos eletrônicos de informação são elementos potencializadores do papel didático-pedagógico da biblioteca, centrados na busca e recuperação de informações, sendo parte embrionária do processo de pesquisa. Tais constatações implicam em redimensionar a instância “biblioteca”, a fim de que possa se transformar em núcleo cultural, reflexivo, e voltado, fundamentalmente, à formação dos sujeitos, tendo a pesquisa como eixo articulador dos processos político-pedagógicos.This study analyzes the use of digital and electronic resources in teacher’s formation in three university libraries: the Federal University of Rio Grande do Sul, the Pontifical Catholic University of Rio Grande do Sul, and the University of Passo Fundo. The interrelationships between culture and education, and the personal ability to understand and adapt to the new emerging culture happens in cyberspace through the virtualization of the information. In this paper we investigate whether the electronic resources of information are elements that enhance the didactic-pedagogical role of the library, being centered on the search and retrieval of information, and becoming a core part of the research process. Finally, the study indicates the need to qualify the library so that it becomes a cultural and reflective space, focused on people’s education, where research is the axis that articulates the political-pedagogical processes

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

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

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

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