1,266 research outputs found

    Prediction of soil water retention properties after stratification by combining texture, bulk density and the type of horizon

    No full text
    International audienceAmong the numerous pedotransfer functions (PTFs) published, class-PTfs have received little attention because their accuracy is often considered limited. However, recent studies show that performance of class-PTFs can be similar to the more popular continuous-PTFs. In this study, we compare the performance of PTFs that were derived from a set of 456 horizons collected in France grouped by combinations of texture, bulk density and type of horizon (topsoil and subsoil). The performance of these class-PTFs was validated against water retained at −33 and −1500 kPa. Our results show that the best performance was obtained with class-PTFs that used both texture and bulk density (texture-structural class-PTFs). They also showed that incorporation of horizon type into the PTF did not improve prediction performance. Comparison of performance at −33 and −1500 kPa showed very little difference, thus indicating no bias according to the value of water potential. Finally, the class-PTFs developed are well suited for predicting water retention properties at the continental and national scales because only very basic soils data are available at these scales. A map of the available water capacity (AWC) was established for France using the 1:1 000 000 Soil Geographical Database of France and an averaged AWC of 104 mm was computed for France

    Environmental Assessment of Soil for Monitoring: Volume IIb Survey of National Networks

    Get PDF
    The ENVASSO Project (Contract 022713) was funded 2006-8, under the European Commission 6th Framework Programme of Research, with the objective of defining and documenting a soil monitoring system appropriate for soil protection at continental level. The ENVASSO Consortium, comprising 37 partners drawn from 25 EU Member States, reviewed almost 300 soil indicators, identified existing soil inventories and monitoring programmes in the Member States, designed and programmed a database management system to capture, store and supply soil profile data, and drafted procedures and protocols appropriate for inclusion in a European soil monitoring network of sites that are geo-referenced and at which a qualified sampling process is or could be conducted. This volume (IIb), a Survey of National Networks, is the second of two reports that together constitute the most comprehensive study to date of the soil inventory and monitoring activities in the European Union. It contains comprehensive fact sheets for each national network, listing the purpose, sampling strategy adopted, analytical methods used and the number of monitoring sites.JRC.H.7-Climate Risk Managemen

    Parent-child interaction in Nigerian families: conversation analysis, context and culture

    Get PDF
    This paper uses a conversation analysis (CA) approach to explore parent child interaction (PCI) within Nigerian families. We illustrate how speech and language therapists (SLTs), by using CA, can tailor recommendations according to the interactional style of each individual family that are consonant with the family’s cultural beliefs. Three parent-child dyads were videoed playing and talking together in their home environments. The analysis uncovered a preference for instructional talk similar to that used in the classroom. Closer examination revealed that this was not inappropriate when considering the context of the activities and their perceived discourse role. Furthermore, this was not necessarily at the expense of responsivity or semantic contingency. The preference for instructional talk appeared to reflect deeply held cultural beliefs about the role of adults and children within the family and it is argued that the cultural paradigm is vitally important to consider when evaluating PCI. Given a potential risk that such young children may be vulnerable in terms of language difficulties, we offer an example of how PCI can be enhanced to encourage language development without disrupting the naturally occurring talk or the underlying purpose of the interaction

    Salmonella enterica subsp. enterica along the pig commodity chain in Vietnam

    Full text link
    Foodborne diseases are a particularly important concern in the current Vietnamese context, shortly after accession to the WTO, not only for public health reasons, but also because of the global evolution of consumer demand and habits, the production chain and state regulations. Salmonella enterica subsp. enterica (Salmonella) is known as one of the most frequent food-borne zoonoses in the world and has been isolated in human and pork products in Vietnam, where pork represents 77% of total meat consumption. The aim of this paper is to describe Salmonella prevalence and epidemiology results along the pig commodity chain, at farm, slaughterhouses (both in Hanoi suburb, 206 samples and in slaughter plants connected with Nam Sach farmers in Hai Duong Province, 126 samples,) and for traditional raw meat fermented Vietnamese sausages 'nem chua'. The prevalences by fattening pigs at farm (19%) and in caecal content before slaughter (52% and 40%) were comparable to other studies, whereas the carcass contamination rates were much higher (95.7% and 67%). 35.7% of 213 'nem chua' samples were positive. Serotyping of these isolates suggested that Salmonella contamination is mainly originated from the pig meat itself, with a smaller contribution from the sausages' processing steps. The results confirm that slaughterhouses in Vietnam are the key point to be focused on for improving food safety in the pork commodity chain. The potential public health threat of Salmonella in pork products has been proven by the high prevalence found on 'nem chua' sausages. Further serotyping and genotyping of Hanoi slaughterhouses' isolates aimed to understand the ways of contamination of Salmonella at this important key step. The direct contamination of carcasses through faecal material from the same pig was not clear, but a direct faecal contamination was observed for the tank and the well water. Thus, our results suggested that the main source of carcass contamination was indirect, through the slaughtering environment. Moreover, the results may indicate that live pigs could be infected during lairage through contaminated water and environment, leading to a persistence of certain clones over longer periods. Since the majority (about 90%) of the pig production in Vietnam goes through small slaughter plants, we propose priority economical hygienic control measures adapted to small plants, that could largely decrease the carcass contamination rate. (Résumé d'auteur

    Probing material nonlinearity at various depths by time reversal mirrors

    No full text
    International audienceIn this letter, the time reversal mirror is used to focus elastic energy at a prescribed location and to analyze the amplitude dependence of the focus signal, thus providing the nonlinearity of the medium. By varying the frequency content of the focused waveforms, the technique can be used to probe the surface, by penetrating to a depth defined by the wavelength of the focused waves. The validity of this concept is shown in the presence of gradual and distributed damage in concrete by comparing actual results with a reference nonlinear measurement and X ray tomography images

    Optimal estimation of qubit states with continuous time measurements

    Get PDF
    We propose an adaptive, two steps strategy, for the estimation of mixed qubit states. We show that the strategy is optimal in a local minimax sense for the trace norm distance as well as other locally quadratic figures of merit. Local minimax optimality means that given nn identical qubits, there exists no estimator which can perform better than the proposed estimator on a neighborhood of size n1/2n^{-1/2} of an arbitrary state. In particular, it is asymptotically Bayesian optimal for a large class of prior distributions. We present a physical implementation of the optimal estimation strategy based on continuous time measurements in a field that couples with the qubits. The crucial ingredient of the result is the concept of local asymptotic normality (or LAN) for qubits. This means that, for large nn, the statistical model described by nn identically prepared qubits is locally equivalent to a model with only a classical Gaussian distribution and a Gaussian state of a quantum harmonic oscillator. The term `local' refers to a shrinking neighborhood around a fixed state ρ0\rho_{0}. An essential result is that the neighborhood radius can be chosen arbitrarily close to n1/4n^{-1/4}. This allows us to use a two steps procedure by which we first localize the state within a smaller neighborhood of radius n1/2+ϵn^{-1/2+\epsilon}, and then use LAN to perform optimal estimation.Comment: 32 pages, 3 figures, to appear in Commun. Math. Phy

    Aquatic community response to volcanic eruptions on the Ecuadorian Andean flank: evidence from the palaeoecological record

    Get PDF
    Aquatic ecosystems in the tropical Andes are under increasing pressure from human modification of the landscape (deforestation and dams) and climatic change (increase of extreme events and 1.5 °C on average temperatures are projected for AD 2100). However, the resilience of these ecosystems to perturbations is poorly understood. Here we use a multi-proxy palaeoecological approach to assess the response of aquatic ecosystems to a major mechanism for natural disturbance, volcanic ash deposition. Specifically, we present data from two Neotropical lakes located on the eastern Andean flank of Ecuador. Laguna Pindo (1°27.132′S–78°04.847′W) is a tectonically formed closed basin surrounded by a dense mid-elevation forest, whereas Laguna Baños (0°19.328′S–78°09.175′W) is a glacially formed lake with an inflow and outflow in high Andean Páramo grasslands. In each lake we examined the dynamics of chironomids and other aquatic and semi-aquatic organisms to explore the effect of thick (> 5 cm) volcanic deposits on the aquatic communities in these two systems with different catchment features. In both lakes past volcanic ash deposition was evident from four large tephras dated to c.850 cal year BP (Pindo), and 4600, 3600 and 1500 cal year BP (Baños). Examination of the chironomid and aquatic assemblages before and after the ash depositions revealed no shift in composition at Pindo, but a major change at Baños occurred after the last event around 1500 cal year BP. Chironomids at Baños changed from an assemblage dominated by Pseudochironomus and Polypedilum nubifer-type to Cricotopus/Paratrichocladius type-II, and such a dominance lasted for approximately 380 years. We suggest that, despite potential changes in the water chemistry, the major effect on the chironomid community resulted from the thickness of the tephra being deposited, which acted to shallow the water body beyond a depth threshold. Changes in the aquatic flora and fauna at the base of the trophic chain can promote cascade effects that may deteriorate the ecosystem, especially when already influenced by human activities, such as deforestation and dams, which is frequent in the high Andes

    Fertilité des sols: conclusions du rapport sur l'état des sols de France

    Get PDF
    Les sols constituent une ressource naturelle non renouvelable. Leurs usages et leur devenir représentent un enjeu collectif majeur, tant pour les activités agricoles ou sylvicoles que pour la préservation de la qualité de notre environnement. Après dix ans de travaux, le Groupement d’Intérêt Scientifique sur les sols, le Gis Sol, a dressé le premier bilan scientifiquement quantifié de l’état des sols de France métropolitaine et d’Outre-mer dans un rapport sur l’état des sols de France publié en 2011. Ce rapport relève des points positifs mais également un certain nombre de préoccupations du point de vue de la fertilité. Les sols agricoles ne présentent pas d’évolution mesurable de leur acidité, ce quiindique une bonne gestion du pH à l’échelle nationale. Le rapport fait en revanche état de teneurs en phosphore relativement faibles pour de nombreux sols, et à l’inverse de situations d’excédents très préoccupantes en raison de son impact sur la qualité des eaux et l’eutrophisation des milieux. Il pose ainsi la question de la durabilité à long terme du système agricole actuel et celle d’une meilleure valorisation des effluents d’élevage. D’assez nombreuses situations pourraient également être susceptibles de provoquer des carences en oligo-éléments pour des cultures exigeantes. Enfin, une inquiétude majeure concerne la progression de l’artificialisation des sols, qui s’est accélérée durant la dernière décennie et occasionne des pertes importantes de sols agricoles.Soils are a non-renewable, natural resource. Their uses and their future represent, therefore, a collective issue for agricultural and forestry production, as well as for the preservation of our environment. After ten years of work, the “Groupement d’intérêt scientifique sur les sols”, the Gis Sol (Soils Scientific Interest Group) has presented the first appraisal of soil quality in mainland France and its overseas territories in a report on the state of the soils in France published in 2011. This appraisal shows evidence for positive points but also highlights some concerns regarding soil fertility. Agricultural soils do not show a measurable change in their acidity, thus indicating an efficient management of pH at a national level. On the other hand, the report shows relatively low phosphorus levels for numerous soils, and inversely situations of structural excess which remain very worrying due to its impact on water quality and on the eutrophication of the environments. It also raises the questionsof the long-term sustainability of current cultivation systems and of a better treatment of effluents from livestock farming. Numerous situations also seem to be incompatible, for certain oligo-elements, with demanding cultures. At last, a major concern is the development of soil sealing, which has accelerated over the last decade and is responsible for the loss of large areas of agricultural soils

    Internal and External Induced Circular Dichroism in Cyclodextrin Complexes: A Study of the Complexes of α-Cyclodextrin with (R)-3-Methylcyclopentanone and Cyclopentanone

    Get PDF
    The circular dichroism (CD) of (R)-3-methylcyclopentanone 1 in the presence of a-cyclodextrin (aCx) in -water has been measured. The formation constant (K\u27 = 24 mol-1 litre) of al-l complex, specific CD (do = +1.74) of 1 in water solution, and specific CD of this complex in water (t1c\u27 = +1.4,5)have been calculated. Similarly, the induced CD (ICD) of cyclopentanone 2 in the presence of aCx in water has been measured. The formation constant (K = 25 mol-1 litre) of a 1-1 complex and the specific CD (t1c\u27 = -0.034)of this complex have been calculated. A model is presented for the interpretation of the lCD data. Various theoretical possibi1ities are discussed. A comparison with X-Ray and low-temperature neutron-diffraction data for the (2-aCx) complex is attempted. It seems reasonable to conclude that there is only a weak chiral discrimination in this complex in water solution at room temperature

    Dwarf Copper-Gold Porphyry Deposits of the Buchim-Damjan-Borov Dol Ore District, Republic of Macedonia (FYROM)

    Get PDF
    The metallogenic aspects, tectonic setting, magmatism, structure, and composition of Au-and Ag-bearing porphyry copper deposits in the Buchim-Damjan-Borov Dol ore district and their genetic features are considered and compared with earlier published data. Special attention is paid to supergene gold in heavy concentrate halos of the Borov Dol deposit. The total Cu reserves of the deposits discussed in this paper do not exceed 150 kt. The Buchim deposit likely is the world's smallest deposit of this type currently involved in mining. A comprehensive study of these dwarf porphyry copper deposits is undertaken to answer questions on the conditions of their formation. How do they differ from formation conditions of giant deposits
    corecore