188 research outputs found
Synthesis and electronic properties of polycyclic aromatic hydrocarbons doped with phosphorus and sulfur
International audienc
Benzofuran-fused Phosphole: Synthesis, Electronic, and Electroluminescence Properties
International audienceA synthetic route to novel benzofuran-fused phosphole derivatives 3-5 is described. These compounds showed optical and electrochemical properties that differ from their benzothiophene analog. Preliminary results show that 4 can be used as an emitter in OLEDs, illustrating the potential of these new compounds for opto-electronic applications
Comparing hydrological responses across catchments using a new soil water content metric
Soil water content (SWC) is a fundamental variable involved in several hydrological processes governing catchment functioning. Comparative analysis of hydrological processes in different catchments based on SWC data is therefore beneficial to infer driving factors of catchment response. Here, we explored the use of high-temporal resolution SWC data in three forested catchments (2.4â60 ha) in different European climates to characterize hydrological responses during wet and dry conditions. The investigated systems include Ressi, Italy, with a humid temperate climate, Weierbach, Luxembourg, with a semi-oceanic climate, and Can Vila, Spain, with a Mediterranean climate. We introduced a new SWC metric defined as the difference between seasonal mean SWC at a relatively shallow and a deep soil layer. The difference is classified in three distinct states: similar SWC between the two layers, higher SWC in the deeper layer, and higher SWC in the shallow layer. In the most humid site, Ressi, we frequently found similar SWC at the two soil depths which was associated with high runoff ratios. Despite similar precipitation amounts in Can Vila and Weierbach, SWC patterns were very different in both catchments. In Weierbach, SWC was similar across the entire soil profile during wet conditions, whereas evaporation of shallow water resulted in higher SWC in the deep soil layer during dry conditions. This led to high runoff ratios during wet conditions and low runoff ratios during dry conditions. In Can Vila, SWC was consistently higher in the deeper layer compared to the shallow layer, irrespective of the season, suggesting an important role of hydraulic redistribution and vertical water movement in this site. Our approach provides an easy and useful method to assess differences in hydrological behaviour solely based on SWC data. As similar datasets are increasingly collected and available, this opens the possibility for further analyses and comparisons in sites around the globe with contrasted physiographic and climate characteristics.C. Segura acknowledges a Fulbright Fellowship that supported her stay at the University of Florence, Italy and the National Science Foundation Award No. 1943574. The Weierbach datasets have been collected in the framework of the Doctoral Training Unit HYDRO-CSI (Innovative methodologies for unravelling hydrological, chemical, and biological interactions across multiple scales), funded by the National Research Fund of Luxembourg (grant PRIDE15/10623093). Data collection in Ressi catchment was supported by the projects âEcohydrological Dynamics and Water Pathways in Forested Catchmentsâ (Bando Starting Grants 2015, Fondazione Cassa di Risparmio di Padova e Rovigo), the project âSILVA-Water fluxes between soil, vegetation and atmosphere: a comparative analysis in two Italian forested catchmentsâ (funded by Premio Florisa Melone 2018, assigned by the Italian Hydrological Society), the Italian MIUR Project (PRIN 2017) âWATer mixing in the critical ZONe: observations and predictions under environmental changes-WATZONâ (code: 2017SL7ABC), and the RETURN Extended Partnership, receiving funding from the European Union Next-GenerationEU (National Recovery and Resilience Plan â NRRP, Mission 4, Component 2, Investment 1.3 â D.D. 1243 2/8/2022, PE0000005). J. Latron and L. Pfister contributions have been supported by the RHYSOTTO (PID2019-106583RB-I00) and WARMed (PID2022-141868NB-I00) projects, both funded by the Spanish Ministry of Science and Innovation (Ministerio de Ciencia e InovaciĂłn, Agencia Estatal de InvestigaciĂłn). J. Latron and L. Pfister also acknowledge the collaboration of Gisel Bertran and Elisenda SĂĄnchez during field work and data collection. The results of this study were discussed within the COST Action: âWATSONâ CA19120. We also thank the constructive reviews from Nitin Singh and an anonymous reviewer.Peer reviewe
Teaching Story without Struggle: Using Graded Readers and Their Audio Packs in the EFL Classroom
In recent years the support for extensive reading (ER) in English as a second or foreign language (ESL/EFL) programs has been compelling. When practicing extensive
reading, the learner reads a wide variety of texts for pleasure and achieves a general understanding of the content while deciphering unknown words through context. This approach contrasts with intensive reading, a more
traditional approach based on a slow, careful reading of a text, with goals of complete comprehension and the
identification of specific details and information
A Standardized Morpho-Functional Classification of the Planetâs Humipedons
It was time to take stock. We modified the humipedon classification key published in 2018 to make it easier and more practical. This morpho-functional taxonomy of the topsoil (humipedon) was only available in English; we also translated it into French and Italian. A standardized morphofunctional classification of humipedons (roughly the top 30â40 cm of soil: organic and organomineral surface horizons) would allow for a better understanding of the functioning of the soil ecosystem. This paper provides the founding principles of the classification of humipedon into humus systems and forms. With the recognition of a few diagnostic horizons, all humus systems can be determined. The humus forms that make up these humus systems are revealed by measuring the thicknesses of the diagnostic horizons. In the final part of the article, several figures represent the screenshots of a mobile phone or tablet application that allows for a fast recall of the diagnostic elements of the classification in the field. The article attempts to promote a standardized classification of humipedons for a global and shared management of soil at planet level
A standardized morpho-functional classification of the planetâs humipedons
It was time to take stock. We modified the humipedon classification key published in 2018 to make it easier and more practical. This morpho-functional taxonomy of the topsoil (humipedon) was only available in English; we also translated it into French and Italian. A standardized morphofunctional classification of humipedons (roughly the top 30â40 cm of soil: organic and organomineral surface horizons) would allow for a better understanding of the functioning of the soil ecosystem. This paper provides the founding principles of the classification of humipedon into humus systems and forms. With the recognition of a few diagnostic horizons, all humus systems can be determined. The humus forms that make up these humus systems are revealed by measuring the thicknesses of the diagnostic horizons. In the final part of the article, several figures represent the screenshots of a mobile phone or tablet application that allows for a fast recall of the diagnostic elements of the classification in the field. The article attempts to promote a standardized classification of humipedons for a global and shared management of soil at planet level
Inter-laboratory comparison of cryogenic water extraction systems for stable isotope analysis of soil water
For more than two decades, research groups in hydrology, ecology, soil
science, and biogeochemistry have performed cryogenic water extractions (CWEs) for
the analysis of ÎŽ2H and ÎŽ18O of soil water.
Recent studies have shown that extraction conditions (time, temperature, and
vacuum) along with physicochemical soil properties may affect extracted soil
water isotope composition. Here we present results from the first worldwide
round robin laboratory intercomparison. We test the null hypothesis that, with
identical soils, standards, extraction protocols, and isotope analyses,
cryogenic extractions across all laboratories are identical. Two standard
soils with different physicochemical characteristics along with deionized
(DI) reference water of known isotopic composition were shipped to 16
participating laboratories. Participants oven-dried and rewetted the soils to
8 and 20âŻ% gravimetric water content (WC), using the deionized reference
water. One batch of soil samples was extracted via predefined extraction
conditions (time, temperature, and vacuum) identical to all laboratories; the
second batch was extracted via conditions considered routine in the
respective laboratory. All extracted water samples were analyzed for
ÎŽ18O and ÎŽ2H by the lead laboratory (Global
Institute for Water Security, GIWS, Saskatoon, Canada) using both a laser and an
isotope ratio mass spectrometer (OA-ICOS and IRMS, respectively). We rejected
the null hypothesis. Our results showed large differences in retrieved
isotopic signatures among participating laboratories linked to soil type and
soil water content with mean differences compared to the reference water ranging from
+18.1 to â108.4âŻâ° for ÎŽ2H and +11.8 to
â14.9âŻâ° for ÎŽ18O across all laboratories. In
addition, differences were observed between OA-ICOS and IRMS isotope data.
These were related to spectral interferences during OA-ICOS analysis that are
especially problematic for the clayey loam soils used. While the types of
cryogenic extraction lab construction varied from manifold systems to single
chambers, no clear trends between system construction, applied extraction
conditions, and extraction results were found. Rather, observed differences
in the isotope data were influenced by interactions between multiple factors
(soil type and properties, soil water content, system setup, extraction
efficiency, extraction system leaks, and each lab's internal accuracy). Our
results question the usefulness of cryogenic extraction as a standard for
water extraction since results are not comparable across laboratories. This
suggests that defining any sort of standard extraction procedure applicable
across laboratories is challenging. Laboratories might have to establish
calibration functions for their specific extraction system for each natural
soil type, individually.</p
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