Search results for " changes"
showing 10 items of 824 documents
Using microtomography, image analysis and flow simulations to characterize soil surface seals
2012
Raindrops that impact on soil surface affect the pore structure and form compact soil surface seals. Damaged pore structure reduces water infiltration which can lead to increased soil erosion. We introduce here methods to characterize the properties of surface seals in a detailed manner. These methods include rainfall simulations, x-ray microtomography, image analysis and pore-scale flow simulations. Methods were tested using clay soil samples, and the results indicate that the sealing process changes several properties of the pore structure.
Testing a portable laser-induced breakdown spectroscopy system on geological samples.
2012
9 pages; International audience; This paper illustrates the potentialities of a home-made portable LIBS (laser-induced breakdown spectroscopy) instrument in Earth sciences, more particularly in geochemically recognizing (i) tephra layers in lacustrine sediments and (ii) fossilization processes in ammonites. Abundances for selected lines of Al, Ca, Fe, Ti, Ba and Na were determined in lacustrine chalk sediments of the Jura, where the Laacher See Tephra (LST) layer is recorded. A statistical treatment of elemental maps produced from the section of a sedimentary column containing the LST event allows instrumental conditions to be optimized. Accumulating spectra from close shot positions gives …
Importance of denitrifiers lacking the genes encoding the nitrous oxide reductase for N2O emissions from soil
2010
Analyses of the complete genomes of sequenced denitrifying bacteria revealed that approximately 1/3 have a truncated denitrification pathway, lacking the nosZ gene encoding the nitrous oxide reductase. We investigated whether the number of denitrifiers lacking the genetic ability to synthesize the nitrous oxide reductase in soils is important for the proportion of N2O emitted by denitrification. Serial dilutions of the denitrifying strain Agrobacterium tumefaciens C58 lacking the nosZ gene were inoculated into three different soils to modify the proportion of denitrifiers having the nitrous oxide reductase genes. The potential denitrification and N2O emissions increased when the size of ino…
Polymer dynamics in thin p-type conducting films investigated by ac-electrogravimetry. Kinetics aspects on anion exclusion, free solvent transfer, an…
2015
A new transfer model is proposed to explain ac-electrogravimetry response of p-doped films. This model takes into account the exclusion effect occurring as a result of the anion transfer. The insertion/expulsion of anions inside a film involves simultaneously the expulsion/insertion of free solvent molecules. The number of solvent molecules excluded depends on the volume of anion transferred. Solvent transfer stimulated by the conformational changes of films constitutes the remaining electrogravimetric response when the exclusion process cannot explain by itself this response. Consequently, the kinetics of this free solvent transfer can be directly related to the kinetics of conformational …
Cambios en los usos del suelo y producción de escorrentía en ramblas mediterráneas: Carraixet y Poyo (1956-1998)
2007
Ana.Camarasa@uv.es Juan.Mateu@uv.es Este trabajo analiza el efecto de los cambios recientes en los usos del suelo en la génesis de escorrentía en ramblas mediterráneas utilizando un SIG. Para el cálculo de la producción de escorrentía se ha utilizado el método desarrollado por el S.C.S. modificado por Témez (1978) que combina los mapas de pendientes, usos del suelo y grupo hidrológico del suelo. Se ha aplicado una adaptación del método propuesta por Camarasa et al. (2006) basado en la interpretación hidrogeomorfológica de la cuenca para la estimación del grupo hidrológico de suelo. Los resultados muestran una variabilidad espacial y temporal importante en la dinámica de producción de escorr…
The Bossons glacier protects Europe's summit from erosion
2013
13 pages; International audience; The contrasting efficiency of erosion beneath cold glacier ice, beneath temperate glacier ice, and on ice-free mountain slopes is one of the key parameters in the development of relief during glacial periods. Detrital geochronology has been applied to the subglacial streams of the north face of the Mont-Blanc massif in order to estimate the efficiency of erosional processes there. Lithologically this area is composed of granite intruded at ~303 Ma within an older polymetamorphic complex. We use macroscopic features (on ~10,000 clasts) and U-Pb dating of zircon (~500 grains) to establish the provenance of the sediment transported by the glacier and its subgl…
How does climate change affect a fishable resource? The case of the royal sea cucumber (Parastichopus regalis) in the central Mediterranean Sea
2022
Holothurians or sea cucumbers are key organisms in marine ecosystems that, by ingesting large quantities of sediments, provide important ecosystem services. Among them, Parastichopus regalis (Cuvier, 1817) is one of the living sea cucumbers in the Mediterranean actively fished for human consumption mainly in Spain, where it is considered a gastronomic delicacy. In the Strait of Sicily (central Mediterranean Sea), this species is not exploited for commercial use even if it is used as bait by longline fishery. P. regalis is frequently caught by bottom trawling and discarded at sea by fishers after catch, and because of its capacity to resist air exposition (at least in cold months), it is rea…
Grammatical changes caused by contact between Livonian and Latvian
2014
The article provides insight into the process of various grammatical changes in Livonian and Latvian that have taken place as a result of prolonged contact between the languages. Livonian is strongly influenced by Latvian at different levels due to the close contact between the speakers of two languages; it is necessary to note that speakers of Livonian were bilinguals for a long time. It is clear that Livonian has affected Latvian in a similar way. The process of mutual borrowings can be observed most clearly in the vocabulary, especially in dialects; however, there are changes that have occurred in the phonetics and grammar as well. Different changes can be found as a result of mutual inf…
A higher incidence of moult–breeding overlap in great tits across time is linked to an increased frequency of second clutches: a possible effect of g…
2021
The rise of temperatures due to global warming is related to a lengthening of the breeding season in many bird species. This allows more pairs to attempt two clutches within the breeding season, thus finishing their breeding activity later in the season and therefore potentially overlapping these with post–breeding moult. We tested whether this occurred in two Spanish great tit Parus major populations. The proportion of pairs laying second clutches increased from 1 % to 32 % over the study period in one of the populations (Sagunto, 1995–2019), while it did not change in the other (Quintos, 2006–2019; mean 5 %). We did not find any temporal trend for moult start date of late–breeding birds i…
Comment on "Lethally hot temperatures during the Early Triassic greenhouse".
2013
Sun et al . (Reports, 19 October 2012, p. 366) reconstructed Permian to Middle Triassic equatorial seawater temperatures. After correct temporal positioning of their data points, their presumed trends of temperature changes, and hence their assumption of a one-to-one relationship between putative "lethally hot" seawater temperatures and a disputable equatorial "eclipse" of some organisms, are no longer supported by their data.