Search results for "Heterogeneity."
showing 10 items of 388 documents
COBieOWL, an OWL ontology based on COBie standard
2015
International audience; Building Information Modelling (BIM) standards have been recognized by construction and political actors as a highly promising tool for resolving issues of data dematerialization, notably in the field of Architecture, Engineering, Construction and Facility Management. Among worldwide-adopted BIM standards, there is COBie. COBie’s goals are to dematerialize building data and to enhance building information interoperability. Nevertheless, COBie data is available in static formats such as STEP or spreadsheet templates. Such formats lack logical formalisms and semantic features provided by languages such as OWL. Because of this, in this paper, we propose a method for sem…
Determinants of the distribution of nitrogen-cycling microbial communities at the landscape-scale
2010
Little information is available regarding the landscape-scale distribution of microbial communities and its environmental determinants. However, a landscape perspective is needed to understand the relative importance of local and regional factors and land management for the microbial communities. In this manuscript, we investigated the distribution of functional microbial communities involved in N-cycling and of the total bacterial and crenarchaeal communities over 107 sites using a grid with a 16 km lag distance within Burgundy, a 31 500 km2 region in France. After quantifying the abundances of the total bacterial, crenarchaeal, nitrate-reducing, denitrifying and ammonia-oxidizing communit…
The multiple facets of Cajal-Retzius neurons.
2021
ABSTRACTCajal-Retzius neurons (CRs) are among the first-born neurons in the developing cortex of reptiles, birds and mammals, including humans. The peculiarity of CRs lies in the fact they are initially embedded into the immature neuronal network before being almost completely eliminated by cell death at the end of cortical development. CRs are best known for controlling the migration of glutamatergic neurons and the formation of cortical layers through the secretion of the glycoprotein reelin. However, they have been shown to play numerous additional key roles at many steps of cortical development, spanning from patterning and sizing functional areas to synaptogenesis. The use of genetic l…
Weed communities in conservation agriculture: what really changes?
2022
Conservation agriculture (CA) has been identified as one of the farming systems likely to deliver sustainable agriculture but its effects over time on the diversity and composition of weed communities are still discussed. For ten years, different studies were carried out in in East of France in cropping system with short rotations essentially composed with winter crops. The objective of these different studies was to identify, focusing on the transition period, the changes in the composition of communities and the consequences in terms of agronomic risk in CA systems. Using networks of 100 winter wheat fields selected to encompass a gradient of years in CA (1 to 20 years), the changes that …
Single cell analysis evidence Heterogeneous expression of the Agr communication system of Listeria monocytogenes
2012
http://prodinra.inra.fr/record/271694EAMERSCT3 EJ3; Communication, often referred as Quorum Sensing, is involved in the adaptation of most bacteria to their environment. In the genus Listeria, the agr communication system affects the biology of Listeria monocytogenes during saprophytic life (biofilm formation) and during infection. In the present study, we investigated in situ agr expression of six isolates of L. monocytogenes by combining gfp reporters, flow cytometry and fluorescent microscopy during plantonic growth and dynamic flow cell biofilm set ups. Unexpectedly, during growth in TSB homogenised liquid cultures incubated at 25°C, while auto-inducer concentration was uniform, statist…
Spatial processes driving soil microbial community assembly on a wide scale
2012
International audience; Soil houses a huge biodiversity involved in ecological services through microbial community assembly. However, processes driving soil microbial community assembly are still scarcely understood, particularly the relative importance of environmental heterogeneity regarding to dispersal limitations. This can be achieved through studying the determinism of taxa-area relationship (TAR, how community composition change with geographic distance), a fundamental relationship in ecology. Here, a biogeographical approach was applied on a wide scale to evaluate TAR for soil bacterial and fungal communities and to partition their spatial variations into environmental heterogeneit…
Geochemistry, Sr–Nd–Pb isotopes and geochronology of amphibole- and mica-bearing lamprophyres in northwestern Iran: Implications for mantle wedge het…
2015
Highlights • Northwestern Iranian lamprophyres have alkaline and calc-alkaline nature. • Studied lamprophyres are emplaced during Late Cretaceous to Late Miocene time. • Lamprophyres originated from different metasomatised lithospheric mantle. Abstract Lamprophyres of different age showing distinctive mineralogy, geochemistry and isotopic ratios are exposed in northwestern Iran. They can be divided into Late Cretaceous sannaite, Late Oligocene-Early Miocene camptonite (amphibole-bearing) and Late Miocene minette (mica-bearing) and spessartite (amphibole-bearing) lamprophyres. Sannaites have high-Ti amphibole along with high-Ti and Al clinopyroxene, and they are characterised by homogeneous …
Intratumoral Heterogeneity, Its Contribution to Therapy Resistance and Methodological Caveats to Assessment
2014
Cancer is one of the most urgent health issues of today. According to WHO, the number of cancer cases is expected to increase by 75% in the next two decades (1). Despite some remarkable achievements in the fields of cancer prevention and early detection, the goal of developing effective anti-cancer therapies still remains unmet. Tumor recurrence due to treatment resistance is the most common cause of death from cancer. Delineating cellular and molecular mechanisms underlying tumor recurrence is of prime importance for the ability to improve the efficacy of existing therapies and develop new strategies to cancer treatment.
Heterogeneity at the glass transition: a review
1999
Theoretical concepts and experimental evidence of heterogeneity in glass-forming liquids and polymers are reviewed. The main purpose is to provide an introduction to theoretical developments and recent experiments which have led to rapidly increasing knowledge. Realizing that there is no consensus in regard to the various scenarios of the glass transition starting from rather different assumptions we try to give a balanced overview although we also compare and interrelate some of the approaches. The experimental part describes recent nuclear magnetic resonance, dielectric, and optical experiments from which dynamically distinguishable subensembles can be selected thus proving the existence …
Studies of structural composition distribution heterogeneity in ethylene/1-hexene copolymers using thermal fractionation technique (SSA): Effect of c…
2005
Investigations into the compositional heterogeneity of ethylene/1-hexene copolymers obtained with various zirconocene/MAO catalysts, either homogeneous or supported on inorganic carriers such as a complex of magnesium chloride with tetrahydrofuran or methyl alcohol, were conducted. The dependence between metallocene structure, as well as catalyst immobilization, and the compositional heterogeneity of the related products was investigated. It was found that the heterogeneity of copolymers is determined by the metallocene catalyst structure. The amount of peaks on the DSC thermograms of copolymers and their division increase with the increase of bulkiness of the ligand in the catalytic system…