Hydrograph separation using isotopic, chemical and hydrological approaches (Strengbach catchment, France)

The streamflow components were determined in a small catchment located in Eastern France for a 40 mm rain event using isotopic and chemical tracing with particular focus on the spatial and temporal variations of catchment sources. Precipitation, soil solution, springwater and streamwaters were sampled and analysed for stable water isotopes (18O and 2H), major chemical parameters (SO4, NO3, Cl2, Na1, K1, Ca21, Mg21, NH4, H1, H4SiO4, alkalinity and conductivity), dissolved organic carbon (DOC) and trace elements (Al, Rb, Sr, Ba, Pb and U). 18O, Si, DOC, Ba and U were finally selected to assess the different contributing sources using mass balance equations and end-member mixing diagrams. Isotopic hydrograph separation shows that the pre-event water only contributes to 2% at the beginning of the stormflow to 13% at the main peak flow. DOC associated to Si and U to Ba allow to identify the different contributing areas (upper layers of the saturated areas, deep layers of the hillslope and rainwater). The streamflow (70%) originates from the deep layers of the hillslope, the remaining being supplied by the small saturated areas. The combination of chemical (both trace and major elements) and isotopic tracers allows to identify the origin of water pathways. During the first stage of the storm event, a significant part of the runoff (30±39%) comes from the small extended saturated areas located down part of the basin (overland runoff then groundwater ridging). During the second stage, the contribution of waters from the deep layers of the hillslope in the upper subcatchment becomes more significant. The final state is characterised by a balanced contribution between aquifers located in moraine and downslopes. Indeed, this study demonstrates the interest of combining a variety of hydrometric data, geochemical and isotopic tracers to identify the components of the streamwater in such conditions

Rethinking the convergence of documentary and entertainment

In what is often considered the first serious book-length study of the documentary, at least in English, Paul Rotha describes “the documentary method as the first real attempt to use cinema for purposes more important than entertainment”. For Rotha, who was a practicing filmmaker as well as a theoretician and promoter of the documentary, this emerging film form should have higher aspirations than the “repetition of senseless stories” offered by fiction films. It should thus aspire to “surpris..

Factores de transferencia suelo-planta de Elementos Tierras Raras en arroz (Oryza sativa L.)

International audienceThe present study describes the distribution and bioaccumulation of rare earth elements (REEs) in rice plants grown in San Pedro farm, located in San José de las Lajas Municipality, Mayabeque Province, Cuba. The results indicate that accumulation of REEs in different parts of plants follows the order: root>leaf>husk>grain. The transfer factor (TF) values of REEs in rice were determined, confirming that REE content in rice grains, roots, leaves and husks do not attempt on their use for human consumption and animal food, respectively.El presente estudio describe la distribución y bioacumulación de Elementos Tierras Raras (ETRs) en plantas de arroz provenientes de la finca San Pedro, ubicada en el municipio de San José de la Lajas, provincia de Mayabeque. Los resultados indican que la acumulación de los ETRs en las diferentes partes de la planta, siguen el comportamiento: raíz>hoja>cáscara>grano. Se determinan los valores del Factor de Transferencia (FT) de ETRs in arroz, confirmando que el contenido de ETRs en los granos de arroz, raíces, horas y cáscaras del grano no atentan contra su empleo como consumo humano y alimento animal, respectivamente

Toxicity of CeO2 nanoparticles on a freshwater experimental trophic chain: A study in environmentally relevant conditions through the use of mesocosms

The toxicity of CeO2 NPs on an experimental freshwater ecosystem was studied in mesocosm, with a focus being placed on the higher trophic level, i.e. the carnivorous amphibian species Pleurodeles waltl. The system comprised species at three trophic levels: (i) bacteria, fungi and diatoms, (ii) Chironomus riparius larvae as primary consumers and (iii) Pleurodeles larvae as secondary consumers. NP contamination consisted of repeated additions of CeO2 NPs over 4 weeks, to obtain a final concentration of 1 mg/L. NPs were found to settle and accumulate in the sediment. No effects were observed on litter decomposition or associated fungal biomass. Changes in bacterial communities were observed from the third week of NP contamination. Morphological changes in CeO2 NPs were observed at the end of the experiment. No toxicity was recorded in chironomids, despite substantial NP accumulation (265.8±14.1mg Ce/kg). Mortality (35.3±6.8%) and a mean Ce concentration of 13.5±3.9mg/kg were reported for Pleurodeles. Parallel experiments were performed on Pleurodeles to determine toxicity pathways: no toxicity was observed by direct or dietary exposures, although Ce concentrations almost reached 100 mg/kg. In view of these results, various toxicity mechanisms are proposed and discussed. The toxicity observed on Pleurodeles in mesocosm may be indirect, due to microorganism’s interaction with CeO2 NPs, or NP dissolution could have occurred in mesocosm due to the structural complexity of the biological environment, resulting in toxicity to Pleurodeles. This study strongly supports the importance of ecotoxicological assessment of NPs under environmentally relevant conditions, using complex biological systems

Trace Element and Pesticide Dynamics During a Flood Event in the Save Agricultural Watershed: Soil-River Transfer Pathways and Controlling Factors

Agricultural practices are the main source of water contamination in rural areas. Rainfall events, and subsequently, soil leaching and storm runoff are mainly controlling the transfer of pollutants from diffuse sources in watersheds during floods. These periods are also very important to better understand their dynamics, particularly their different soil-river transfer pathways (surface runoff SR, subsurface runoff SSR, and groundwater flow GF). This study focuses on riverine transfers of both pesticides and trace elements. High-resolution monitoring of water discharge and water sampling were performed during a flood event that occured in May 2010 in an agricultural catchment of SWFrance. Chemical composition of major and trace elements, silica, alkalinity, pH and conductivity, DOC and POC, TSM, and commonly used pesticides were analyzed with a high sampling frequency. The different stream flow components (SR, SSR, and GF) were assessed using two independent hydrograph separation methods: a hydrological approach based on Maillet’s formula (1905) for the recession period and a chemical approach based on physico-chemical tracers, TSM for SR and PO43− for GF. Both methods exhibited important contributions of SR (33 %) and SSR (40 %) to the total riverine pollutant transfers. The contribution of different components was also visible using concentration-discharge relationships which exhibited hysteresis phenomenon between the rising and the falling limbs of the hydrograph. Higher concentrations during the rising period(clockwise hysteresis) were characteristic of pollutants mainly exported by SR (trifluralin, Cd). Anticlockwise hysteresis with higher concentration during the recession period showed pollutants mainly exported by SSR (metolachlor, Cu). Moreover, significant relationships were highlighted between the controlling factors (DOC,POC, and TSM) and SR, SSR, and GF contributions:DOC and the complexed pollutants were highly correlated to SSR while POC, TSM, and the adsorbed pollutants were linked to SR. During the flood, Kd of most pollutants increased, particularly at the beginning, and therefore,future studies should investigate their availability to living organisms and thus their toxicity. An additional characteristic equation between Kd and Kow of the different pesticides was proposed to help future management, modelling,and estimation of pollutant transfers during floods

Multi-walled carbon nanotubes, natural organic matter, and the benthic diatom Nitzschia palea: “A sticky story”

Different effects of multi-walled carbon nanotubes (MWCNTs) on the freshwater diatom Nitzschia palea were examined. MWCNTs used in this study (MWCNT) were dispersed either by sonication without (MWCNTsonicated) or with a realistic concentration (10mgL-1) of Natural Organic Matter (MWCNT+NOM). A pocket-size device was designed to distinguish shading effect (using MWCNT suspensions as external filters) from total exposure effect of MWCNTsonicated and MWCNT+NOM on benthic algae. This study demonstrates that cell division was strongly inhibited after a 48 h exposure to MWCNT+NOM compared to MWCNTsonicated. This device did not yield a quantifiable contribution of shading to growth inhibition of MWCNTsonicated and below 10mgL-1 of MWCNT+NOM. In all cases, neither lethal effects nor drops in photosynthetic quantum yield were observed. After a 6-d exposure, a complete growth recovery was observed for all conditions except at the highest concentration of MWCNT+NOM. Different microscopic approaches using carbohydrates markers revealed the strong affinity between MWCNT and extracellular polymeric substances (EPS) produced by N. palea. These seem to constitute a defensive mechanism against MWCNT

De los métodos y las maneras, número 8

Por octava ocasión el Posgrado en Diseño de la división de Ciencias y Artes para el Diseño, en colaboración con el comité organizador de “De los métodos y las maneras”, logró reunir investigaciones de especialistas en el ámbito del diseño y la investigación, así como de alumnos de tres de las cinco líneas de investigación del posgrado de diseño. Este libro es muestra de una constante al presentar temas en torno a las metodologías para hacer investigación en Diseño, además de ser una herramienta teórico - práctica, para apoyar tanto a docentes como estudiantes de los posgrados en diseño.Coordinación del Posgrado de Ciencias y Artes para el DiseñoGustavo Iván Garmendia Ramírez, coordinador; Sandra Rodríguez Mondragón, compilación y diseño editorial; Martín Lucas Flores Carapia, Diseño de la portad

Gender Inequality and Economic Growth

Gender inequality is a pervasive feature in many developing countries. The gaps between male and female outcomes and opportunities are present in several dimensions: education, earnings, occupation, access to formal employment, access to managerial positions, access to productive inputs, political representation, or bargaining power inside the household. These gaps are particularly dramatic in developing countries. Dollar and Gatti (1999) estimate the following education gap in schooling: in the poorest quartile of countries in 1990, only 5% of adult women had any secondary education, one-half of the level for men. In the richest quartile, on the other hand, 51% of adult women had at least some secondary education, 88% of the level for men. On the other hand, the gaps in employment and pay are closing much faster in developing countries than they did in industrialized ones (Tzannatos, 1999), but the prevalence of gender inequality is still sizable, especially in South Asia and the Middle East and North Africa (Klasen and Lamanna, 2009). Moreover, the majority of family workers are women and, often unpaid. Women are also underrepresented among top positions in most countries: even in the most developed ones, the average incidence of females among managers is less than 30% (World Bank 2001). The data also shows that women are typically employed in a reduced number of industrial sectors: more than two-thirds of the global labor force in garment production is females and 1/5th of the total female labor force is in manufacturing

Preliminary evaluation of computer-assisted home training for French cochlear implant recipients.

For French cochlear implant (CI) recipients, in-person clinical auditory rehabilitation is typically provided during the first few years post-implantation. However, this is often inconvenient, it requires substantial time resources and can be problematic when appointments are unavailable. In response, we developed a computer-based home training software ("French AngelSound™") for French CI recipients. We recently conducted a pilot study to evaluate the newly developed French AngelSound™ in 15 CI recipients (5 unilateral, 5 bilateral, 5 bimodal). Outcome measures included phoneme recognition in quiet and sentence recognition in noise. Unilateral CI users were tested with the CI alone. Bilateral CI users were tested with each CI ear alone to determine the poorer ear to be trained, as well as with both ears (binaural performance). Bimodal CI users were tested with the CI ear alone, and with the contralateral hearing aid (binaural performance). Participants trained at home over a one-month period (10 hours total). Phonemic contrast training was used; the level of difficulty ranged from phoneme discrimination in quiet to phoneme identification in multi-talker babble. Unilateral and bimodal CI users trained with the CI alone; bilateral CI users trained with the poorer ear alone. Outcomes were measured before training (pre-training), immediately after training was completed (post-training), and one month after training was stopped (follow-up). For all participants, post-training CI-only vowel and consonant recognition scores significantly improved after phoneme training with the CI ear alone. For bilateral and bimodal CI users, binaural vowel and consonant recognition scores also significantly improved after training with a single CI ear. Follow-up measures showed that training benefits were largely retained. These preliminary data suggest that the phonemic contrast training in French AngelSound™ may significantly benefit French CI recipients and may complement clinical auditory rehabilitation, especially when in-person visits are not possible

Subsurface H2S Detection by a Surface Acoustic Wave Passive Wireless Sensor Interrogated with a Ground Penetrating Radar

International audienceLong-term monitoring of organic pollutants in the soil is a major environmental challenge. We propose to meet this issue by the development of a polymer dedicated to selectively react with H2S, coating surface acoustic wave transducers designed as passive cooperative targets with the compound, and probing their response using Ground Penetrating RADAR, thus providing the capability to monitor the presence of H2S in the subsurface environment. The selectivity is brought by including lead(II) cation in a reticulated polymer matrix which can be deposited as a thin layer on a surface acoustic wave sensor. We demonstrate a signal enhancement mechanism in which water absorption magnifies the signal detection, making the sensor most sensitive to H2S in an underground environment saturated with moisture