156 research outputs found
Méthode d'évaluation de l'action de conseil en irrigation IRRIPARC en régions Nord-Pas-de-Calais et Picardie
Parmi les nombreuses actions de conseil en irrigation dĂ©veloppĂ©es en France, trop peu d'entre elles sont Ă©valuĂ©es pour apprĂ©cier leur impact sur les pratiques d'irrigation et les bĂ©nĂ©fices pour la ressource. Dans cet article, nous proposons une mĂ©thode d'Ă©valuation de l'une d'entre elles, sur l'Ă©tude d'un cas concret : l'action IRRIPARC. Dans les rĂ©gions Nord-Pas-de-Calais et Picardie, des fiches de rĂ©glages de canons enrouleurs ont Ă©tĂ© diffusĂ©es aux agriculteurs, pour limiter les effets du vent sur l'uniformitĂ© de la rĂ©partition de l'eau d'irrigation. La mĂ©thode d'Ă©valuation proposĂ©e repose sur l'Ă©tude de trois critĂšres : l'efficacitĂ©, la pertinence et la cohĂ©rence de l'action. La collecte des donnĂ©es se fait par enquĂȘtes quantitatives et qualitatives auprĂšs de diffĂ©rents acteurs : les agriculteurs, public cible de l'action, et les partenaires impliquĂ©s dans l'action IRRIPARC. L'analyse dĂ©bouche sur des perspectives d'Ă©volution et fournit des recommandations pour l'action. / Several technical support actions in irrigation have been carried out in France. However, very few have been evaluated to determine their actual impact on irrigation practices and their water saving benefits. In this paper, an assessment method of a technical support action is presented on a concrete case: the IRRIPARC action. The action was carried in the Nord Pas-de-Calais region of France. It aims at providing to farmers technical forms to help them to set their irrigation guns according to the wind speed in order to improve water distribution uniformity. The method depends on three criteria based on the effectiveness, the relevance and the consistency of the action. The data have been collected through quantitative and qualitative enquiries to different stakeholders: farmers to which the action was intended, and other partners which were involved in the action. The analysis results in evolution perspective of IRRIPARC action
The Expectation Monad in Quantum Foundations
The expectation monad is introduced abstractly via two composable
adjunctions, but concretely captures measures. It turns out to sit in between
known monads: on the one hand the distribution and ultrafilter monad, and on
the other hand the continuation monad. This expectation monad is used in two
probabilistic analogues of fundamental results of Manes and Gelfand for the
ultrafilter monad: algebras of the expectation monad are convex compact
Hausdorff spaces, and are dually equivalent to so-called Banach effect
algebras. These structures capture states and effects in quantum foundations,
and also the duality between them. Moreover, the approach leads to a new
re-formulation of Gleason's theorem, expressing that effects on a Hilbert space
are free effect modules on projections, obtained via tensoring with the unit
interval.Comment: In Proceedings QPL 2011, arXiv:1210.029
Autonomous and self-sustained circadian oscillators displayed in human islet cells
Aims/hypothesis: Following on from the emerging importance of the pancreas circadian clock on islet function and the development of type 2 diabetes in rodent models, we aimed to examine circadian gene expression in human islets. The oscillator properties were assessed in intact islets as well as in beta cells. Methods: We established a system for long-term bioluminescence recording in cultured human islets, employing lentivector gene delivery of the core clock gene Bmal1 (also known as Arntl)-luciferase reporter. Beta cells were stably labelled using a rat insulin2 promoter fluorescent construct. Single-islet/cell oscillation profiles were measured by combined bioluminescence-fluorescence time-lapse microscopy. Results: Human islets synchronised in vitro exhibited self-sustained circadian oscillations of Bmal1-luciferase expression at both the population and single-islet levels, with period lengths of 23.6 and 23.9h, respectively. Endogenous BMAL1 and CRY1 transcript expression was circadian in synchronised islets over 48h, and antiphasic to REV-ERBα (also known as NR1D1), PER1, PER2, PER3 and DBP transcript circadian profiles. HNF1A and PDX1 exhibited weak circadian oscillations, in phase with the REV-ERBα transcript. Dispersed islet cells were strongly oscillating as well, at population and single-cell levels. Importantly, beta and non-beta cells revealed oscillatory profiles that were well synchronised with each other. Conclusions/interpretation: We provide for the first time compelling evidence for high-amplitude cell-autonomous circadian oscillators displayed in human pancreatic islets and in dispersed human islet cells. Moreover, these clocks are synchronised between beta and non-beta cells in primary human islet cell culture
Spatial and temporal robustness of Sr/CaâSST calibrations in Red Sea corals : evidence for influence of mean annual temperature on calibration slopes
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Paleoceanography and Paleoclimatology 33 (2018): 443-456, doi:10.1029/2017PA003276.Sr/Ca ratios recorded in the aragonite skeleton of massive coral colonies are commonly used to reconstruct seasonalâ to centennialâscale variability in sea surface temperature (SST). While the Sr/Ca paleothermometer is robust in individual colonies, Sr/CaâSST relationships between colonies vary, leading to questions regarding the utility of the proxy. We present biweeklyâresolution calibrations of Sr/Ca from five Porites spp. corals to satellite SST across 10° of latitude in the Red Sea to evaluate the Sr/Ca proxy across both spatial and temporal scales. SST is significantly correlated with coral Sr/Ca at each site, accounting for 69â84% of Sr/Ca variability (P âȘ 0.01). Intercolony variability in Sr/CaâSST sensitivities reveals a latitudinal trend, where calibration slopes become shallower with increasing mean annual temperature. Mean annual temperature is strongly correlated with the biweeklyâresolution calibration slopes across five Red Sea sites (r2 = 0.88, P = 0.05), while also correlating significantly to Sr/CaâSST slopes for 33 Porites corals from across the entire IndoâPacific region (r2 = 0.26, P < 0.01). Although interannual summer, winter, and mean annual calibrations for individual Red Sea colonies are inconsistently robust, combined multicoral calibrations are significant at summer (r2 = 0.53, P âȘ 0.01), winter (r2 = 0.62, P âȘ 0.01), and mean annual time scales (r2 = 0.79, P âȘ 0.01). Our multicoral, multisite study indicates that the Sr/Ca paleothermometer is accurate across both temporal and spatial scales in the Red Sea and also potentially explains for the first time variability in Sr/CaâSST calibration slopes across the IndoâPacific region. Our study provides strong evidence supporting the robustness of the coral Sr/Ca proxy for examining seasonal to multicentury variability in global climate phenomena.Singapore Ministry of Education;
National Research Foundation Singapore Grant Number: NRFFâ2012â03;
U.S. National Science Foundation Grant Number: OCEâ1031288;
King Abdullah University of Science and Technology Grant Numbers: USA 00002, KSA 0001
Autonomous and self-sustained circadian oscillators displayed in human islet cells
Aims/hypothesis: Following on from the emerging importance of the pancreas circadian clock on islet function and the development of type 2 diabetes in rodent models, we aimed to examine circadian gene expression in human islets. The oscillator properties were assessed in intact islets as well as in beta cells. Methods: We established a system for long-term bioluminescence recording in cultured human islets, employing lentivector gene delivery of the core clock gene Bmal1 (also known as Arntl)-luciferase reporter. Beta cells were stably labelled using a rat insulin2 promoter fluorescent construct. Single-islet/cell oscillation profiles were measured by combined bioluminescence-fluorescence time-lapse microscopy. Results: Human islets synchronised in vitro exhibited self-sustained circadian oscillations of Bmal1-luciferase expression at both the population and single-islet levels, with period lengths of 23.6 and 23.9h, respectively. Endogenous BMAL1 and CRY1 transcript expression was circadian in synchronised islets over 48h, and antiphasic to REV-ERBα (also known as NR1D1), PER1, PER2, PER3 and DBP transcript circadian profiles. HNF1A and PDX1 exhibited weak circadian oscillations, in phase with the REV-ERBα transcript. Dispersed islet cells were strongly oscillating as well, at population and single-cell levels. Importantly, beta and non-beta cells revealed oscillatory profiles that were well synchronised with each other. Conclusions/interpretation: We provide for the first time compelling evidence for high-amplitude cell-autonomous circadian oscillators displayed in human pancreatic islets and in dispersed human islet cells. Moreover, these clocks are synchronised between beta and non-beta cells in primary human islet cell culture
The Gut Microbiota Regulates Intestinal CD4Â T Cells Expressing RORÎłt and Controls Metabolic Disease
SummaryA high-fat diet (HFD) induces metabolic disease and low-grade metabolic inflammation in response to changes in the intestinal microbiota through as-yet-unknown mechanisms. Here, we show that a HFD-derived ileum microbiota is responsible for a decrease in Th17 cells of the lamina propria in axenic colonized mice. The HFD also changed the expression profiles of intestinal antigen-presenting cells and their ability to generate Th17 cells in vitro. Consistent with these data, the metabolic phenotype was mimicked in RORγt-deficient mice, which lack IL17 and IL22 function, and in the adoptive transfer experiment of T cells from RORγt-deficient mice into Rag1-deficient mice. We conclude that the microbiota of the ileum regulates Th17 cell homeostasis in the small intestine and determines the outcome of metabolic disease
Categorial Compositionality: A Category Theory Explanation for the Systematicity of Human Cognition
Classical and Connectionist theories of cognitive architecture seek to explain systematicity (i.e., the property of human cognition whereby cognitive capacity comes in groups of related behaviours) as a consequence of syntactically and functionally compositional representations, respectively. However, both theories depend on ad hoc assumptions to exclude specific instances of these forms of compositionality (e.g. grammars, networks) that do not account for systematicity. By analogy with the Ptolemaic (i.e. geocentric) theory of planetary motion, although either theory can be made to be consistent with the data, both nonetheless fail to fully explain it. Category theory, a branch of mathematics, provides an alternative explanation based on the formal concept of adjunction, which relates a pair of structure-preserving maps, called functors. A functor generalizes the notion of a map between representational states to include a map between state transformations (or processes). In a formal sense, systematicity is a necessary consequence of a higher-order theory of cognitive architecture, in contrast to the first-order theories derived from Classicism or Connectionism. Category theory offers a re-conceptualization for cognitive science, analogous to the one that Copernicus provided for astronomy, where representational states are no longer the center of the cognitive universeâreplaced by the relationships between the maps that transform them
Sceptrin, a Marine Natural Compound, Inhibits Cell Motility in a Variety of Cancer Cell Lines
The Sheaf-Theoretic Structure Of Non-Locality and Contextuality
We use the mathematical language of sheaf theory to give a unified treatment
of non-locality and contextuality, in a setting which generalizes the familiar
probability tables used in non-locality theory to arbitrary measurement covers;
this includes Kochen-Specker configurations and more. We show that
contextuality, and non-locality as a special case, correspond exactly to
obstructions to the existence of global sections. We describe a linear
algebraic approach to computing these obstructions, which allows a systematic
treatment of arguments for non-locality and contextuality. We distinguish a
proper hierarchy of strengths of no-go theorems, and show that three leading
examples --- due to Bell, Hardy, and Greenberger, Horne and Zeilinger,
respectively --- occupy successively higher levels of this hierarchy. A general
correspondence is shown between the existence of local hidden-variable
realizations using negative probabilities, and no-signalling; this is based on
a result showing that the linear subspaces generated by the non-contextual and
no-signalling models, over an arbitrary measurement cover, coincide. Maximal
non-locality is generalized to maximal contextuality, and characterized in
purely qualitative terms, as the non-existence of global sections in the
support. A general setting is developed for Kochen-Specker type results, as
generic, model-independent proofs of maximal contextuality, and a new
combinatorial condition is given, which generalizes the `parity proofs'
commonly found in the literature. We also show how our abstract setting can be
represented in quantum mechanics. This leads to a strengthening of the usual
no-signalling theorem, which shows that quantum mechanics obeys no-signalling
for arbitrary families of commuting observables, not just those represented on
different factors of a tensor product.Comment: 33 pages. Extensively revised, new results included. Published in New
Journal of Physic
- âŠ