A new PPN parameter to test Chern-Simons gravity

We study Chern-Simons (CS) gravity in the parameterized post-Newtonian (PPN) framework through a weak-field solution of the modified field equations. We find that CS gravity possesses the same PPN parameters as general relativity, except for the inclusion of a new term, proportional to the CS coupling and the curl of the PPN vector potential. This new term leads to a modification of frame dragging and gyroscopic precession and we provide an estimate of its size. This correction might be used in experiments, such as Gravity Probe B, to bound CS gravity and test string theory.Comment: 4 pages, replaced with version accepted for publication in Phys. Rev. Letters (December, 2007

Finite element study of hyperstructure systems with modular light‐frame construction in high‐rise buildings

To answer both the growth of the world's urban population and the climate changes, new structural systems with high prefabrication levels and renewable materials need to be developed. A novel structural system that could enable the use of modular light‐frame construction in high‐rise buildings was modeled and analyzed. This system was achieved by having a hyperstructure carrying the loads of four‐story light‐frame superposed substructures. Two 20‐story hyperstructures, one using glulam and another one using reinforced concrete, were designed according to the 2015 National Building Code of Canada and compared. A simplified model for the light‐frame modules according to the CSA O86‐19 was proposed. The interaction between both systems and the impact on the substructures were analyzed. The results of the response spectrum analysis and dynamic wind analysis show that, with a glulam hyperstructure, modules could be connected to the columns and the floors or only to the floors. With a concrete hyperstructure, the modules must be connected to the columns and the cores. For both systems, the design of shearwalls on the short side of the modules is governed by the lateral deformation imposed by seismic forces, while the design of shearwalls on the long side of the modules is governed by the vertical deformation of the primary beams under gravity loads. Standard shearwall assemblies are sufficient to resist the shear induced by gravitational, wind and seismic loads. The analysis indicates that the system could be viable, but more research should be especially performed on the connections between the substructures and the hyperstructure

Prediction of sunflower leaf area at vegetative stage by image analysis and application to the estimation of water stress response parameters in post-registration varieties

The automatic measurement of developmental and physiological responses of sunflowers to water stress represents an applied challenge for a better knowledge of the varieties available to growers, but also a fundamental one for identifying the biological, genetic and molecular bases of plant response to their environment.On INRAE Toulouse's Heliaphen high-throughput phenotyping platform, we set up two experiments, each with 8 varieties (2*96 plants), and acquired images of plants subjected or not to water stress, using a light barrier on a daily basis. At the same time, we manually measured the leaf surfaces of these plants every other day for the duration of the stress, which lasted around ten days. The images were analyzed to extract morphological characteristics of the segmented plants and different models were evaluated to estimate total plant leaf areas using these data.A linear model with a posteriori smoothing was used to estimate total leaf area with a relative squared error of 11% and an efficiency of 93%. Leaf areas estimated conventionally or with the developed model were used to calculate the leaf expansion and transpiration responses (LER and TR) used in the SUNFLO crop model for 8 sunflower varieties studied. Correlation coefficients of 0.61 and 0.81 for LER and TR respectively validate the use of image-based leaf area estimation. However, the estimated values for LER are lower than for the manual method on Heliaphen, but closer overall to the manual method on greenhouse-grown plants, potentially suggesting an overestimation of stress sensitivity.It can be concluded that the LE and TR parameter estimates can be used for simulations. The low cost of this method (compared with manual measurements), the possibility of parallelizing and repeating measurements on the Heliaphen platform, and of benefiting from the Heliaphen platform's data management, are major improvements for valorizing the SUNFLO model and characterizing the drought sensitivity of cultivated varieties.Comment: in French languag

Genetic control of plasticity of oil yield for combined abiotic stresses using a joint approach of crop modeling and genome-wide association

Understanding the genetic basis of phenotypic plasticity is crucial for predicting and managing climate change effects on wild plants and crops. Here, we combined crop modeling and quantitative genetics to study the genetic control of oil yield plasticity for multiple abiotic stresses in sunflower. First we developed stress indicators to characterize 14 environments for three abiotic stresses (cold, drought and nitrogen) using the SUNFLO crop model and phenotypic variations of three commercial varieties. The computed plant stress indicators better explain yield variation than descriptors at the climatic or crop levels. In those environments, we observed oil yield of 317 sunflower hybrids and regressed it with three selected stress indicators. The slopes of cold stress norm reaction were used as plasticity phenotypes in the following genome-wide association study. Among the 65,534 tested SNP, we identified nine QTL controlling oil yield plasticity to cold stress. Associated SNP are localized in genes previously shown to be involved in cold stress responses: oligopeptide transporters, LTP, cystatin, alternative oxidase, or root development. This novel approach opens new perspectives to identify genomic regions involved in genotype-by-environment interaction of a complex traits to multiple stresses in realistic natural or agronomical conditions.Comment: 12 pages, 5 figures, Plant, Cell and Environmen

Clonal expansion of sequence type (ST-)5 and emergence of ST-7 in serogroup A meningococci, Africa.

One hundred four serogroup A meningococci in our collection, isolated in Africa from 1988 to 1999, were characterized by multilocus sequence typing (MLST). Our results and data from the Internet indicate that sequence type 5 (ST-5) strains were responsible for most of African outbreaks and sporadic cases during this period. In 1995, a new clone, characterized by ST-7 sequence, emerged and was responsible for severe outbreaks in Chad (1998) and Sudan (1999). MLST and epidemiologic data indicate that ST-5 and ST-7 represent two virulent clones. These two STs, which belong to subgroup III, differ only in the pgm locus: allele pgm3 is characteristic for ST-5 and allele pgm19 for ST-7. Subgroup III strains were responsible for two pandemics in the 1960s and 1980s. Our data show that the third subgroup III pandemic has now reached Africa

Role of substrate outgassing on the formation dynamics of either hydrophilic or hydrophobic wood surfaces in atmospheric-pressure, organosilicon plasmas

This work examines the influence of substrate outgassing on the deposition dynamics of either hydrophilic or hydrophobic coatings on wood surfaces in organosilicon, dielectric barrier discharges. Sugar maple and black spruce wood samples were placed on the bottom electrode and the discharge was sustained in N2–HMDSO (hexamethyldisiloxane) gas mixtures by applying a 24 kV peak-to-peak voltage at 2 kHz. Current–voltage characteristics revealed a transition from a filamentary to a homogeneous discharge with increasing plasma treatment time, t. Based on opticalemission spectroscopy, the filamentary behaviorwas ascribed to the release of air and humidity from the wood substrate following discharge exposure which produced significant quenching of N2 metastables. This effect vanished at longer treatment times due to the nearly complete “pumping” of products from the wood substrate and the progressive deposition of a “barrier” layer. Analysis of the surface wettability through static, water contact angles (WCAs) and of the surface composition through Fourier-Transform-Infra-Red-Spectroscopy and X-ray-Photoelectron-Spectroscopy indicated that for t b 10 min, the wood surface was more hydrophilic due to the formation of a SiOx layer, a typical behavior for HMDSO deposition in presence of oxygen. On the other hand, for t > 10 min, the static WCA increased up to ~140° due to the deposition of hydrophobic Si(CH3)3-O-Si(CH3)2, Si(CH3)3, and Si(CH3)2 functional groups

Direct generation of a multi-transverse mode non-classical state of light

Quantum computation and communication protocols require quantum resources which are in the continuous variable regime squeezed and/or quadrature entangled optical modes. To perform more and more complex and robust protocols, one needs sources that can produce in a controlled way highly multimode quantum states of light. One possibility is to mix different single mode quantum resources. Another is to directly use a multimode device, either in the spatial or in the frequency domain. We present here the first experimental demonstration of a device capable of producing simultanuously several squeezed transverse modes of the same frequency and which is potentially scalable. We show that this device, which is an Optical Parametric Oscillator using a self-imaging cavity, produces a multimode quantum resource made of three squeezed transverse modes

Human leukocytes differentially express endocannabinoid-glycerol lipases and hydrolyze 2-arachidonoyl-glycerol and its metabolites from the 15-lipoxygenase and cyclooxygenase pathways

2-Arachidonoyl-glycerol (2-AG) is an endocannabinoid with anti-inflammatory properties. Blocking 2-AG hydrolysis to enhance CB2 signaling has proven effective in mouse models of inflammation. However, the expression of 2-AG lipases has never been thoroughly investigated in human leukocytes. Herein, we investigated the expression of seven 2-AG hydrolases by human blood leukocytes and alveolar macrophages (AMs) and found the following protein expression pattern: monoacylglycerol (MAG lipase; eosinophils, AMs, monocytes), carboxylesterase (CES1; monocytes, AMs), palmitoyl-protein thioesterase (PPT1; AMs), α/β-hydrolase domain (ABHD6; mainly AMs), ABHD12 (all), ABHD16A (all), and LYPLA2 (lysophospholipase 2; monocytes, lymphocytes, AMs).We next found that all leukocytes could hydrolyze 2-AG and its metabolites derived from cyclooxygenase-2 (prostaglandin E2-glycerol [PGE2-G]) and the 15-lipoxygenase (15-hydroxy-eicosatetraenoyl-glycerol [15-HETE-G]). Neutrophils and eosinophils were consistently better at hydrolyzing 2-AG and its metabolites than monocytes and lymphocytes. Moreover, the efficacy of leukocytes to hydrolyze 2-AG and its metabolites was 2-AG ≥ 15-HETE-G >> PGE2-G for each leukocyte. Using the inhibitors methylarachidonoyl-fluorophosphonate (MAFP), 4-nitrophenyl-4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate (JZL184), Palmostatin B, 4′-carbamoylbiphenyl-4-yl methyl(3-(pyridin-4-yl)benzyl)carbamate, Nmethyl-N-[[3-(4-pyridinyl)phenyl]methyl]-4′-(aminocarbonyl) [1,1′-biphenyl]-4-yl ester carbamic acid (WWL70), 4′-[[[methyl[[3-(4-pyridinyl)phenyl]methyl]amino]carbonyl]oxy]-[1,1′-biphenyl]-4-carboxylic acid, ethyl ester (WWL113), tetrahydrolipstatin, and ML349, we could not pinpoint a specific hydrolase responsible for the hydrolysis of 2-AG, PGE2-G, and 15-HETE-G by these leukocytes. Furthermore, JZL184, a selective MAG lipase inhibitor, blocked the hydrolysis of 2-AG, PGE2-G, and 15-HETE-G by neutrophils and the hydrolysis of PGE2-G and 15-HETE-G by lymphocytes, two cell types with limited/no MAG lipase. Using an activity-based protein profiling (ABPP) probe to label hydrolases in leukocytes, we found that they expressmanyMAFP-sensitive hydrolases and an unknown JZL184-sensitive hydrolase of ~52 kDa. Altogether, our results indicate that human leukocytes are experts at hydrolyzing 2-AG and its metabolites via multiple lipases and probably via a yet-to-be characterized 52 kDa hydrolase. Blocking 2-AG hydrolysis in humans will likely abrogate the ability of human leukocytes to degrade 2-AG and its metabolites and increase their anti-inflammatory effects in vivo

Spatial variability of potassium in agricultural soils of the canton of Fribourg, Switzerland

Potassium (K) is a crucial element for plant nutrition and its availability and spatial distribution in agricultural soils is influenced by many agro-environmental factors. In Switzerland, a soil monitoring network (FRIBO) was established in 1987 with 250 sites distributed over the whole of the canton of Fribourg (representing 4% of the surface area of Switzerland), whose territory is shared between the Swiss Midlands and the Western Alp foothills. In this study area, diverse geological deposits (sandstone, marlstone, silts and calcareous rocks), soil types (Cambisols, Gleysols, Rendzinas, Luvisols and Fluvisols) and land uses (cropland, permanent grassland and mountain pasture) are present, making the network interesting for assessing the relative contribution of environmental variables and land use management on soil properties. The aims of the present study were to (i) characterize the soil K status in the Fribourg canton according to four different extraction methods; (ii) analyse the spatial variability of soil K in relation to land use, soil type, soil parent material and topography; (iii) evaluate the spatial predictability of K at the canton level; and (iv) analyse the implications for K fertilization management. The overall amount of soil total K averaged 13.6 g.kg-1 with significant variations across the sites (5.1-22.1 g.kg-1). The spatial distribution of total K was particularly influenced by soil parent materials, as suggested by a significant global spatial autocorrelation measure (Moran’s I10km = 0.43) and significant differences observed among soil types and soil parent materials. On the other hand, available mean K forms were significantly different among land uses, with the highest mean values of available K encountered in permanent grasslands, from 46.3 mg.kg-1 (water extraction) to 198 mg.kg-1 (acetate ammonium + EDTA extraction). All K forms showed similar spatial regional patterns for all spatial interpolation methods, with areas dominated by permanent grassland and crops presenting higher values. However, these trends were less pronounced for the available K forms due to the prevalence of on-farm management practices for these K forms and their high temporal variability. This hypothesis was supported by spatial clustering of low and/or high K fertility status that could be related to local particular farming practices. Grasslands require particular attention with regard to overall high K fertility status