Search results for " Gradient"
showing 10 items of 575 documents
Mapping spatial patterns of denitrifiers for bridging community ecology and microbial processes along environmental gradients
2009
While there is ample evidence that microbial processes can exhibit large variations at a field scale, very little is known about the spatial distribution of the communities mediating these processes. The objective of this study was to explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes. We used geostatistical modeling to map the distribution of size and activity of the denitrifier community in the pasture. Size of the denitrifier community was estimated by PCR quantification of the denitrification gene copy numbers while its activity was estimated by measurin…
High-throughput sequencing of amplicons for monitoring yeast biodiversity in must and during alcoholic fermentation
2014
Abstract We compared pyrosequencing technology with the PCR-ITS-RFLP analysis of yeast isolates and denaturing gradient gel electrophoresis (DGGE). These methods gave divergent findings for the yeast population. DGGE was unsuitable for the quantification of biodiversity and its use for species detection was limited by the initial abundance of each species. The isolates identified by PCR-ITS-RFLP were not fully representative of the true population. For population dynamics, high-throughput sequencing technology yielded results differing in some respects from those obtained with other approaches. This study demonstrates that 454 pyrosequencing of amplicons is more relevant than other methods …
Genome‐phenotype‐environment associations identify signatures of selection in a panmictic population of threespine stickleback
2023
Adaptive genetic divergence occurs when selection imposed by the environment causes the genomic component of the phenotype to differentiate. However, genomic signatures of natural selection are usually identified without information on which trait is responding to selection by which selective agent(s). Here we integrate whole-genome-sequencing with phenomics and measures of putative selective agents to assess the extent of adaptive divergence in threespine stickleback occupying the highly heterogeneous lake Mývatn, NE Iceland. We find negligible genome wide divergence, yet multiple traits (body size, gill raker structure and defence traits) were divergent along known ecological gradients (t…
1400 years of man-environment interactions and soil evolution in the Saint-Mont mountain (Remiremont, Vosges)
2021
International audience; The SolHoM(a) project aims at determining the degree of landscape anthropisation in the Fossard massif (Remiremont, Vosges, France) by estimating the impact of past human occupations on current soils. Nowadays, a forest covers this relatively inhospitable mountain (hard climate, steep slopes, acid soils ...), but some remains suggest human presence for at least 1400 years.The Saint-Mont is a variscan orogenic granitic summit (height 672m) with valuable preserved archaeological relics, located south of the Fossard. At the top was founded the monasterium Habendum (from the 7th century to the French Revolution), which potentially comes after a late-antic castrum.Further…
A Low Cost Customizable Micro-ROV for Environmental Research - Applications, Advances and Challenges
2016
Summary Several shallow submarines areas are characterized by considerable releases of hydrocarbon gases, which, during earthquakes or volcanic activity, may suddenly and violently occur. In some instances, changes in chemical and physical properties of gas emissions, which are generated by geothermal systems connected to the volcanoes’ plumbing system, are important precursors of volcanic activity and useful indices for the study of the geothermal field. Furthermore, some superficial structures such faults, landslide slopes or archaeological relics should be studied with such a high detail that geophysical and bathymetric surveys are unable to provide. In response to the needs increasingly…
Ferromagnetic ordering in GdPdCd
2010
Abstract GdPdCd was obtained in pure form via reaction of the elements in a sealed tantalum tube in a high-frequency furnace. The structure was investigated by X-ray diffraction on both powders and single crystals: ZrNiAl type, P 6 2m , a=758.2(1), c=391.78(7) pm, wR2=0.0410 for 358 F2 values and 14 variables. Striking structural motifs of GdPdCd are two types of palladium-centered tricapped trigonal prisms [Pd1Cd3Gd6] and [Pd2Cd6Gd3]. Together the palladium and cadmium atoms build a three-dimensional network in which the gadolinium atoms fill distorted pentagonal channels. Susceptibility measurements reveal Curie–Weiss behaviour with an effective magnetic moment of 8.2(1) μB/Gd. GdPdCd ord…
Comparison of inoculums in the removal of 2-butoxyethanol from air emissions by biotrickling filter: Performance and microbial monitoring
2014
2-butoxyethanol is one of the most used glycol ether in industrial activities and the treatment of air 2-butoxyethanol-emissions become necessary. Biotechnologies are potential treatment technologies due to their low operational costs. The use of two inoculums in the treatment of 2-butoxyethanol by biotrickling filters (BTFs) packed with polyurethane-foam was studied. A pure culture of Pseudomonas putida, previously adapted to 2-butoxyethanol, was used as inocula in a BTF operated in the University of Stuttgart. Fresh activated sludge from a municipal waste water treatment plant was used as inocula in a BTF operated in the University of Valencia. An empty bed residence time of 12.5 s and in…
Influence of lactose-citrate co-metabolism on the differences of growth and energetics in Leuconostoc lactis, Leuconostoc mesenteroides ssp. mesenter…
1999
International audience; The biodiversity of growth and energetics in Leuconostoc sp. has been studied in MRS lactose medium with and without citrate. On lactose alone, Ln. lactis has a growth rate double that of Ln. cremoris and Ln. mesenteroides. The pH is a more critical parameter for Ln. mesenteroides than for Ln. lactis or Ln. cremoris; without pH control Ln. mesenteroides is unable to acidify the medium under pH 4.5, while with pH control and as a consequence of a high Y(ATP) its growth is greater than Ln. lactis and Ln. cremoris. In general, lactose-citrate co-metabolism increases the growth rate, the biomass synthesis, the lactose utilisation ratio, and the production of lactate and …
Coupling of proton translocation through ATPase incorporated into supported lipid bilayers to an electrochemical process
1997
Abstract H+-ATPase is incorporated into solid-supported lipid bilayers separated from the gold support by a peptide spacer. The translocation of protons across the lipid film to the inner side is coupled to the discharge of protons at the gold surface. The overall process is investigated by square wave voltammetry (SWV) and double potential-pulse chronoamperometry (CA). As a result, the formation of a proton gradient is monitored by SWV whereas currents measured by CA monitor the stationary state when the enzyme activity is directly coupled to the charge transfer at the electrode. These currents markedly depend on the number of ATPases present in the bilayer.
Gravity-Driven Infiltration and Subsidence Phenomena in Posidonia oceanica Residues
2019
A simplified infiltration model for highly permeable porous media was introduced, assuming the matric potential gradient as negligible compared to the gravitational gradient. This model enabled us to determine the delay time, i.e., the time that the water front takes (from the beginning of rainfall) to reach the bottom of the highly permeable layer. Posidonia oceanica (Linnaeus) Delile residues were used as a porous media, in order to study the infiltration process that provides salt leaching under natural rainfall when these residues are arranged in a storage area, before reusing. By using a laboratory rainfall simulator, delay times were measured to verify the applicability of the aforeme…