Estimating causal networks in biosphere–atmosphere interaction with the PCMCI approach

Local meteorological conditions and biospheric activity are tightly coupled. Understanding these links is an essential prerequisite for predicting the Earth system under climate change conditions. However, many empirical studies on the interaction between the biosphere and the atmosphere are based on correlative approaches that are not able to deduce causal paths, and only very few studies apply causal discovery methods. Here, we use a recently proposed causal graph discovery algorithm, which aims to reconstruct the causal dependency structure underlying a set of time series. We explore the potential of this method to infer temporal dependencies in biosphere-atmosphere interactions. Specifically we address the following questions: How do periodicity and heteroscedasticity influence causal detection rates, i.e. the detection of existing and non-existing links? How consistent are results for noise-contaminated data? Do results exhibit an increased information content that justifies the use of this causal-inference method? We explore the first question using artificial time series with well known dependencies that mimic real-world biosphere-atmosphere interactions. The two remaining questions are addressed jointly in two case studies utilizing observational data. Firstly, we analyse three replicated eddy covariance datasets from a Mediterranean ecosystem at half hourly time resolution allowing us to understand the impact of measurement uncertainties. Secondly, we analyse global NDVI time series (GIMMS 3g) along with gridded climate data to study large-scale climatic drivers of vegetation greenness. Overall, the results confirm the capacity of the causal discovery method to extract time-lagged linear dependencies under realistic settings. The violation of the method's assumptions increases the likelihood to detect false links. Nevertheless, we consistently identify interaction patterns in observational data. Our findings suggest that estimating a directed biosphere-atmosphere network at the ecosystem level can offer novel possibilities to unravel complex multi-directional interactions. Other than classical correlative approaches, our findings are constrained to a few meaningful set of relations which can be powerful insights for the evaluation of terrestrial ecosystem models

High-temperature phase transitions in SrBi_2Ta_2O_9 film: a study by THz spectroscopy

Time-domain THz transmission experiment was performed on a $\rm SrBi_2Ta_2O_9$ film deposited on sapphire substrate. Temperatures between 300 and 923 K were investigated and complex permittivity spectra of the film were determined. The lowest frequency optic phonon near 28 cm$^{-1}$ reveals a slow monotonic decrease in frequency on heating with no significant anomaly near the phase transitions. We show that the dielectric anomaly near the ferroelectric phase transition can be explained by slowing down of a relaxational mode, observed in the THz spectra. A second harmonic generation signal observed in a single crystal confirms a loss of center of symmetry in the ferroelectric phase and a presence of polar clusters in the intermediate ferroelastic phase.Comment: subm. to J. Phys.: Condens. Matte

Analyzing the impact of spanish university funding policies on the evolution of their performance: a multi-criteria approach

The relationship between university performance and performance-based funding models has been a topic of debate for decades. Promoting performance-based funding models can create incentives for improving the educational and research effectiveness of universities, and consequently providing them with a competitive advantage over its competitors. Therefore, this paper studies how to measure the performance of a university through a mathematical multicriteria analysis and tries to link these results with certain university funding policies existing in the Spanish case. To this end, a reference point-based technique is used, which allows the consideration and aggregation of all the aspects regarded as relevant to assess university performance. The simple and easy way in which the information is provided by this technique makes it valuable for decision makers because of considering two aggregation scenarios: the fully compensatory scenario provides an idea of the overall performance, while the non-compensatory one detects possible improvement areas. This study is carried out in two stages. First, the main results of applying the proposed methodology to the performance analysis evolution of the largest three Spanish public university, over a period of five academic years, are described. Second, a discussion is carried out about some interesting features of the analysis proposed at regional level, and some policy messages are provided. The “intra” regions university performance analysis reveals some institutions with noteworthy behaviors, some with sustained trends throughout the analyzed period and other institutions with more erratic behaviors, within the same regional public university system despite having the identical funding model. However, the findings “inter” regions also reveal that only Catalonia has developed a true performance-based model, in theory and in practice, which has contributed to achieving excellent results at regional level in both teaching and researchThis research was partially funded by the Spanish Ministry of Economy and Competitiveness (Project PID2019-104263RB-C42), from the Regional Government of Andalucía (Project P18-RT-1566), and by the EU ERDF operative program (Project UMA18-FEDERJA-065

Accurate solutions for radiative heat transfer in two-dimensional axisymmetric enclosures with gas radiation and reflective surfaces

Il y a une erreur d'impression à l'intérieur de la revue, qui indique pour référence le volume 46. Il s'agit bien du volume 47, n°1.International audienceAccurate solutions for benchmarking purposes in two-dimensional axisymmetric enclosures with reflective surfaces have been obtained using the Monte Carlo method (MCM) based on the net exchange formulation (NEF). Previous applications of the MCM-NEF have been restricted to multidimensional problems with black boundaries or one-dimensional problems with gray boundaries. Here, the extension to multidimensional enclosures with gray boundaries is presented. The medium is a mixture of H 2 O, CO 2 , N 2 , and soot at atmospheric pressure, and its radiative properties are computed using the correlated k-distribution method. Predictions obtained using the discrete ordinates method are included, showing good agreement with the benchmark MCM=NEF solutions

Supporting communication and language development in nurseries/daycares in Lebanon: realities and representations of SLTs and educators

Background : It is widely recognized that professional’s representations and beliefs about language development can impact practices in the field of preventing language and literacy difficulties ((Piasta et al., 2009; Dickinson & Brady, 2006). This study focuses on the context of daycares in Lebanon. It aims to explore practices, identify needs, barriers and motivations for the implementation of a language intervention program, led jointly by speech therapists and caregivers in the multilingual and multicultural Lebanese context. International recommendations highlight the necessity for SLTs to conceptualize their intervention, according to community based needs, focusing on primary prevention for early language difficulties, given their later impact on social and professional integration (Law 2013). Method: a survey study through questionnaires developed according to Lebanese context specifications of will be proposed to different publics: 1) nurseries/daycares directors, 2) educators/caregivers, 3) Speech therapists. Each questionnaire will include items about language support practices, professional roles and the collaboration between SLTs and caregivers in Lebanese nurseries. Results: Findings will be discussed in the context of the realities of nurseries in Lebanon by defining the beliefs and practices in the area of prevention as well as the opportunities of collaboration between caregivers and SLT’s in prevention program models. Cultural differences and backgrounds of various stakeholders would influence findings. This study is a part of a wider project on prevention practices in Lebanon. Results will be analyzed along with the study targeting kindergartens in the same context.Implémentation du programme "Parler Bambin" dans le contexte multilingue et multiculturel des crèches au Liba

A mini review focused on the proangiogenic role of silicate ions released from silicon-containing biomaterials

Angiogenesis is considered an important issue in the development of biomaterials for the successful regeneration of tissues including bone. While growth factors are commonly used with biomaterials to promote angiogenesis, some ions released from biomaterials can also contribute to angiogenic events. Many silica-based biomaterials have been widely used for the repair and regeneration of tissues, mainly hard tissues such as bone and tooth structure. They have shown excellent performance in bone formation by stimulating angiogenesis. The release of silicate and others (Co and Cu ions) has therefore been implicated to play critical roles in the angiogenesis process. In this short review, we highlight the in vitro and in vivo findings of angiogenesis (and the related bone formation) stimulated by the various types of silicon-containing biomaterials where silicate ions released might play essential roles. We discuss further the possible molecular mechanisms underlying in the ion-induced angiogenic events

Proteínas secretadas por el haustorio y su importancia en el desarrollo de Podosphaera xanthii

El cultivo de las cucurbitáceas en España se ve afectado, entre otros problemas, por Podosphaera xanthii, un hongo biotrofo obligado y principal agente causal del oídio de las cucurbitáceas. Este hongo, que requiere células vivas de la planta para completar su ciclo de vida asexual, desarrolla unas estructuras especiales de parasitismo denominadas haustorios. Los haustorios prosperan dentro de las células epidérmicas y son responsables de la relación directa entre el patógeno y el hospedador, participando en la absorción de nutrientes de la planta y en la liberación de efectores en las células del huésped. Dada la estrecha relación entre los haustorios y las células vegetales, desarrollamos un transcriptoma haustorial de novo de P. xanthii y definimos su secretoma con la intención de encontrar proteínas secretadas que sean esenciales para la patogénesis. De esta manera pudimos identificar diferentes proteínas, la mayoría de ellas sin función anotada, expresadas específicamente en el haustorio. Gracias al modelado proteico obtuvimos información relevante sobre la posible función de alguna de estas proteínas secretadas sin anotación funcional y seleccionamos varias para su validación funcional mediante silenciamiento génico en el hospedador mediado por Agrobacterium (ATM-HIGS). Además, la expresión heteróloga de las proteínas seleccionadas y los subsecuentes ensayos enzimáticos nos ha permitido corroborar su actividad bioquímica predicha. Así, pudimos comprobar cómo proteínas secretadas específicamente por el haustorio son muy importantes para el desarrollo fúngico. Este abordaje multidisciplinar nos ha permitido identificar y dilucidar la función de proteínas esenciales para P. xanthii que, dado su papel clave, se convierten en dianas esperanzadoras para el desarrollo de nuevo fitosanitarios contra el oídio de las cucurbitáceas y otros hongos fitopatógenos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad (AGL2013-41939-R; AGL2016-76216-C2-1-R) cofinanciado con fondos FEDER (UE). Álvaro Polonio es beneficiario de un contrato predoctoral (BES-2014-068602) para la formación de doctores del Ministerio de Economía y Competitividad. Los autores también agradecen ayudas del Plan Propio de Investigación de la Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Formation of an epitaxial monolayer on graphite upon short-time surface contact with highly diluted aqueous solutions of 1-monostearoylglycerol

Short-time surface contact of highly diluted 1-monostearoylglycerol (1-MSG) aqueous solutions with highly oriented pyrolitic graphite results in the deposition of an epitaxial monolayer that can be detected by atomic force microscopy operating in tapping mode at the graphite-air interface. The monolayer obtained with the racemic mixture is then compared to that obtained with one of the pure enantiomers. The analogous behavior found for aqueous solutions of rac-1-MSG and 3-sn-MSG implies a two-dimensional self-assembly process with chiral discrimination. The results suggest that the monolayer originates from species located at the surface of the deposition drop. They also indicate that the simple experimental procedure reported, or more elaborate Langmuir-Schaefer methods, could be the method of choice to prepare other monolayers of similar surfactants