A cost-effective method to quantify biological surface sediment reworking

We propose a simple and inexpensive method to determine the rate and pattern of surface sediment reworking by benthic organisms. Unlike many existing methods commonly used in bioturbation studies, which usually require sediment sampling, our approach is fully non-destructive and is well suited for investigating non-cohesive fine sediments in streams and rivers. Optical tracer (e.g., luminophores or coloured sand) disappearance or appearance is assessed through time based on optical quantification of surfaces occupied by tracers. Data are used to calculate surface sediment reworking (SSR) coefficients depicting bioturbation intensities. Using this method, we evaluated reworking activity of stream organisms (three benthic invertebrates and a fish) in laboratory microcosms mimicking pool habitats or directly in the field within arenas set in depositional zones. Our method was sensitive enough to measure SSR as low as 0.2 cm2.d-1, such as triggered by intermediate density (774 m-2) of Gammarus fossarum (Amphipoda) in microcosms. In contrast, complex invertebrate community in the field and a fish (Barbatula barabatula) in laboratory microcosms were found to yield to excessively high SSR (>60 cm2.d-1). Lastly, we suggest that images acquired during experiments can be used for qualitative evaluation of species-specific effects on sediment distribution

Effect of early, short-term supplementation on weight and linear growth of 4-7-mo-old infants in developing countries : a four-country randomized trial

The effect of supplementation on growth was tested by means of four similar controlled randomized trials in the Congo (n = 120), Senegal (n = 110), Bolivie (n = 127), and New Caledonia (n = 90). Four month-old infants were randomly allocated to supplement or control groups. A cereal-based precooked porridge was offered twice daily for 3 mo and consumption was monitored. Both groups were free to eat local food. At 7 mo of age, all infants were still breast-fed in the Congo, Senegal, and Bolivia compared with 47% in the New Caledonia. Mean daily consumption of the supplement varied among countries (558-790 kJ/d). Mean length at 4 mo was lowest in Bolivia, higher in Senegal and the Congo, and near the National Center for Health Statistics reference in New Caledonia. The mean 4-7 mo length increment was 0,48 cm higher for supplemented than for control infants in Senegal (P < 0.05), whereas weight increments did not differ. No significant effect was found in the other countries. (Résumé d'auteur

Strong quantum memory at resonant Fermi edges revealed by shot noise

Studies of non-equilibrium current fluctuations enable assessing correlations involved in quantum transport through nanoscale conductors. They provide additional information to the mean current on charge statistics and the presence of coherence, dissipation, disorder, or entanglement. Shot noise, being a temporal integral of the current autocorrelation function, reveals dynamical information. In particular, it detects presence of non-Markovian dynamics, i.e., memory, within open systems, which has been subject of many current theoretical studies. We report on low-temperature shot noise measurements of electronic transport through InAs quantum dots in the Fermi-edge singularity regime and show that it exhibits strong memory effects caused by quantum correlations between the dot and fermionic reservoirs. Our work, apart from addressing noise in archetypical strongly correlated system of prime interest, discloses generic quantum dynamical mechanism occurring at interacting resonant Fermi edges.Comment: 6 pages, 3 figure

Potassium limitation of forest productivity – Part 2: CASTANEA-MAESPA-K shows a reduction in photosynthesis rather than a stoichiometric limitation of tissue formation

Potassium (K) availability constrains forest productivity. Brazilian eucalypt plantations are a good example of the K limitation of wood production. Here, we built upon a previously described model (CASTANEA-MAESPA-K) and used it to understand whether the simulated decline in C source under K deficiency was sufficient to explain the K limitation of wood productivity in Brazilian eucalypt plantations. We developed allocation schemes for both C and K and included these in CASTANEA-MAESPA-K. Neither direct limitations of the C-sink activity nor direct modifications of the C allocation by K availability were included in the model. Simulation results show that the model was successful in replicating the observed patterns of wood productivity limitation by K deficiency. Simulations also show that the response of net primary productivity (NPP) is not linear with increasing K fertilisation. Simulated stem carbon use and water use efficiencies decreased with decreasing levels of K availability. Simulating a direct stoichiometric limitation of NPP or wood growth was not necessary to reproduce the observed decline of productivity under K limitation, suggesting that K stoichiometric plasticity could be different to that of N and P. Confirming previous results from the literature, the model simulated an intense recirculation of K in the trees, suggesting that retranslocation processes were essential for tree functioning. Optimal K fertilisation levels calculated by the model were similar to nutritional recommendations currently applied in Brazilian eucalypt plantations, paving the way for validation of the model at a larger scale and of this approach for developing decision-making tools to improve fertilisation practices.</p

National Forest Funds: mechanisms adapted to today’s challenges - Overview of the situation of 4 Southern and Eastern Mediterranean countries: Lebanon, Morocco, Tunisia and Turkey

National Forest Funds (NFFs) are mechanisms that could be adapted to address today’s many challenges: their role as funding instruments, they can also act as catalysts to harness international funding such as the REDD+. If properly set, an NFF can also be an efficient tool to rationalize the use of these funds in a context of good governance and to ensure, for example, a redistribution to environmental service providers such as through payments for ecosystem services. Well equipped to deal with global changes, such as increasing anthropogenic stress with poverty in Southern and Eastern Mediterranean countries, which increase wooded areas degradation and withering and desertification due to climate change. An overview of the situation of 4 Southern and Eastern Mediterranean countries (Lebanon, Morocco, Tunisia, and Turkey) was compiled in order to take stock of the context and of the purpose of the implementation or the reinforcement of a national forest fund in terms of development opportunities, structuring, cross sectoral approach, objectives and schedule

Les Fonds forestiers nationaux : des mécanismes adaptés aux défis d’aujourd’hui - Tour d’horizon de la situation de quatre pays du sud et de l’est de la Méditerranée : Liban, Maroc, Tunisie et Turquie

Les fonds forestiers nationaux (FFN) sont des mécanismes adaptés aux défis d’aujourd’hui : en plus d’être un instrument de financement, ils peuvent également être un catalyseur en appelant des financements internationaux tels que la REDD+ par exemple. Correctement habilité, un FFN peut également être un outil efficient pour rationaliser l’utilisation des fonds dans le cadre d’une bonne gouvernance et assurer par exemple une redistribution vers les fournisseurs des services environnementaux dans le cadre de mécanismes de paiements pour services écosystémiques. Autant d’atouts pour mieux faire face aux changements globaux, tels que les pressions anthropiques croissantes et les phénomènes de pauvreté dans les pays du sud et de l’est de la Méditerranée, qui accroissent les dégradations aux espaces boisés mais également les phénomènes de dépérissements et de désertification inhérents au changement climatique. Un tour d’horizon de la situation de quatre pays du sud et de l’est de la Méditerranée (Liban, Maroc, Tunisie et Turquie) est réalisé afin de faire le point sur le contexte dans chaque pays et l’intérêt de la mise en place ou du renforcement d’un fonds forestier national en termes d’opportunités de développement, de structuration, d’approche intersectorielle, d’objectifs et de calendrier

Glucosylsphingosine Is a Highly Sensitive and Specific Biomarker for Primary Diagnostic and Follow-Up Monitoring in Gaucher Disease in a Non-Jewish, Caucasian Cohort of Gaucher Disease Patients

Gaucher disease (GD) is the most common lysosomal storage disorder (LSD). Based on a deficient β-glucocerebrosidase it leads to an accumulation of glucosylceramide. Standard diagnostic procedures include measurement of enzyme activity, genetic testing as well as analysis of chitotriosidase and CCL18/PARC as biomarkers. Even though chitotriosidase is the most well-established biomarker in GD, it is not specific for GD. Furthermore, it may be false negative in a significant percentage of GD patients due to mutation. Additionally, chitotriosidase reflects the changes in the course of the disease belatedly. This further enhances the need for a reliable biomarker, especially for the monitoring of the disease and the impact of potential treatments.Here, we evaluated the sensitivity and specificity of the previously reported biomarker Glucosylsphingosine with regard to different control groups (healthy control vs. GD carriers vs. other LSDs).Only GD patients displayed elevated levels of Glucosylsphingosine higher than 12 ng/ml whereas the comparison controls groups revealed concentrations below the pathological cut-off, verifying the specificity of Glucosylsphingosine as a biomarker for GD. In addition, we evaluated the biomarker before and during enzyme replacement therapy (ERT) in 19 patients, demonstrating a decrease in Glucosylsphingosine over time with the most pronounced reduction within the first 6 months of ERT. Furthermore, our data reveals a correlation between the medical consequence of specific mutations and Glucosylsphingosine.In summary, Glucosylsphingosine is a very promising, reliable and specific biomarker for GD