Search results for "changes"

Monitoring soil volume wetness in heterogeneous soils by electrical resistivity. A field-based pedotransfer function.: A field-based pedotransfer fun…

2014

11 pages; International audience; Modern irrigation techniques require accurate, rapid, cost-effective, spatial measurement of soil moisture. Electrical Resistivity Tomography (ERT) meets most of these requirements, but needs to be calibrated for each use because it is very sensitive to differences in soil characteristics. In this study, a pedotransfer function approach is used to remove the need for site-specific calibration, allowing ERT to be used directly to measure soil moisture. The study site was a hillslope vineyard, where eight calcaric-cambisol soil profiles were identified. From 2012 to 2013, 23 000 soil volume wetness measurements were acquired by Time Domain Reflectometry, and …

History teaching: real problems and interessed polemics

2006

En diversos países se ha tratado de poner límites a las innovaciones educativas, de diverso calado, que se estaban produciendo en la enseñanza de la historia, con la intención de retornar a un modelo de enseñanza más próximo a sus características tradicionales, a pesar de las muy razonadas críticas que este modelo tradicional había recibido. Las razones aducidas para tal reversión han variado de un país a otro, pero el objetivo compartido ha sido el de establecer unos programas más dirigistas y cerrados, de tipo marcadamente enciclopédico, en los que las posibilidades de actuación innovadora del profesorado, por una parte, y las de un aprendizaje más razonado del alumnado, por la otra, qued…

Isolation and characterisation of Nocardioides sp. SP12, an atrazine-degrading bacterial strain possessing the gene trzN from bulk- and maize rhizosp…

2003

International audience; We report the characterisation of Nocardioides sp. SP12, an atrazine-degrading bacteria isolated from atrazine-treated bulk- and maize rhizosphere soil. Based on 16S rDNA alignment, strain SP12 showed close phylogenic relationships with Nocardioides sp. C157 and Nocardioides simplex. Internal transcribed spacer (ITS) sequences of strain SP12 were longer than those of other Nocardioides sp. and present Ala- and Ile-tRNA unlike Actinomycetales. Nocardioides sp. SP12 presents a novel atrazine catabolic pathway combining trzN with atzB and atzC. Atrazine biodegradation ends in a metabolite that co-eluted in HPLC with cyanuric acid. This metabolite shows an absorption spe…

Interannual persistence effects in vegetation dynamics of semi-arid Africa

2005

[1] Over 15 years of Normalized Difference Vegetation Index (NDVI) data from the Advanced Very High Resolution Radiometers (AVHRR) are used to study the response of vegetation activity to rainfall in three semi-arid regions of Africa. The relationships between annual NDVI and annual precipitation (PPT) time series are examined using statistical approaches (simple and partial correlations, linear multiple regressions). It appears that annual NDVI highly depends on PPT of the concurrent year and the previous year. An analysis of particularly dry and wet years enables to better diagnose two distinct responses of vegetation activity to rainfall. The “recovery” effect represents the difficulty o…

Reliability and effectiveness of Ellenberg’s indices in checking flora and vegetation changes induced by climatic variations

2001

Two methods are proposed to assess the significance of time-spanned local variations of Ellenberg’s indicator values in floristic and phytosociological data sets respectively. Both methods are based on frequencies and averages of the indicator values within and among data sets. Main goal of proposed methods is to determine the threshold above which the observed variations are to be considered significant. In order to relate the observed floristic variations to recent climatic changes, attention was focused on the Ellenberg’s indices dealing with the main climatic variables: heliophany, temperature and precipitation. Study-cases from Zannone Island (Pontine Archipelago, Mediterranean region)…

Long-term changes in the water temperature of rivers in Latvia

2016

Abstract The study describes the trends of monthly mean water temperature (from May to October) and the annual maximum water temperature of the rivers in Latvia during the time period from 1945 to 2000. The results demonstrated that the mean water temperatures during the monitoring period from May to October were higher in the largest rivers (from 13.6 °C to 16.1 °C) compared to those in the smallest rivers (from 11.5 °C to 15.7 °C). Similar patterns were seen for the maximum water temperature: in large rivers from 22.9 °C to 25.7 °C, and in small rivers from 20.8 °C to 25.8 °C. Generally, lower water temperatures occurred in rivers with a high groundwater inflow rate, for example, in river…

Les Hypogées d'Arles-Fontvieille et leur environnement : nouvelles perceptions, nouvelles perspectives

2014

Due to their unique architecture and the exceptional dimensions of the largest monument in the group, the Arles-Fontvieille hypogea are among the most remarkable megalithic monuments in Europe and the western Mediterranean region. A collective research program was launched in 2013 to study these well-known monuments which have, paradoxically, been the subject of relatively few field studies since the 19th century. The research program consisted of an inventory and analysis of the grave goods and associated artefacts, as well as a number of field studies providing an improved archaeological context of a megalithic group too often thought of only in terms of funerary monuments. Various traces…

New Arrivals, Old Places: Demographic Changes and New Planning Challenges in Naples and Palermo

2008

Impacts interculturels au Néolithique moyen. Du terroir au territoire : sociétés et espaces.

2006

International audience; INTERACTIONS CULTURELLES ET EMPRISE DES SOCIÉTÉS NÉOLITHIQUES SUR LES ESPACES"Interactions culturelles", "espaces", voilà bien des sujets que certains pourraient qualifier de rebattus ! Diverses éditions antérieures du colloque néolithique n'ont-elles pas fait de l'un ou l'autre leur thème central ? Leur choix, pour ce colloque ne relèverait-il alors que d'une soumission aux vogues du moment ? On privilégie en effet volontiers ces derniers temps les débats touchant aux relations interculturelles. Et il paraît de bon ton de sacrifier aux approches spatiales, quand ce n'est pas à leur seul instrument, le "SIG". Mais, au delà de ces considérations un peu simplistes, ce …

Predicting in situ soil N2O emission using NOE algorithm and soil database

2005

This paper presents a new algorithm, Nitrous Oxide Emission (NOE) for simulating the emission of the greenhouse gas N2O from agricultural soils. N2O fluxes are calculated as the result of production through denitrification and nitrification and reduction through the last step of denitrification. Actual denitrification and nitrification rates are calculated from biological parameters and soil water-filled pore space, temperature and mineral nitrogen contents. New suggestions in NOE consisted in introducing (1) biological site-specific parameters of soil N2O reduction and (2) reduction of the N2O produced through nitrification to N2 through denitrification. This paper includes a database of 6…