Khovanov homology for signed divides

The purpose of this paper is to interpret polynomial invariants of strongly invertible links in terms of Khovanov homology theory. To a divide, that is a proper generic immersion of a finite number of copies of the unit interval and circles in a 2-disc, one can associate a strongly invertible link in the 3-sphere. This can be generalized to signed divides : divides with + or - sign assignment to each crossing point. Conversely, to any link $L$ that is strongly invertible for an involution $j$, one can associate a signed divide. Two strongly invertible links that are isotopic through an isotopy respecting the involution are called strongly equivalent. Such isotopies give rise to moves on divides. In a previous paper of the author, one can find an exhaustive list of moves that preserves strong equivalence, together with a polynomial invariant for these moves, giving therefore an invariant for strong equivalence of the associated strongly invertible links. We prove in this paper that this polynomial can be seen as the graded Euler characteristic of a graded complex of vector spaces. Homology of such complexes is invariant for the moves on divides and so is invariant through strong equivalence of strongly invertible links

Economies of Scale in the Canadian Food Processing Industry

Cost functions for three Canadian manufacturing agri-food sectors (meat, bakery and dairy) are estimated using provincial data from 1990 to 1999. A translog functional form is used and the concavity property is imposed locally. The Morishima substitution elasticities and returns to scale elasticities are computed for different provinces. Inference is carried out using asymptotic theory as well as bootstrap methods. In particular, the ability of the double bootstrap to provide refinements in inference is investigated. The evidence suggests that there are significant substitution possibilities between the agricultural input and other production factors in the meat and bakery sectors. Scale elasticity parameters indicate that increasing returns to scale are present in small bakery industries. While point estimates suggest that increasing returns to scale exist at the industry level in the meat sector, statistical inference cannot rule the existence of decreasing returns to scale. To account for supply management in the dairy sector, separability between raw milk and the other inputs was introduced. There exists evidence of increasing returns to scale at the industry level in the dairy industries of Alberta and New Brunswick. The scale elasticity for the two largest provinces (Ontario and Quebec) is greater than one, but inference does not reject the null hypothesis of increasing returns to scale.Translog cost function; Canadian food processing industry; returns to scale; double bootstrap

Ultrafast radial modulation imaging

International audienceRadial modulation imaging improves the detection of microbubbles at high frequency by using a dual ultrasonic excitation. However, the synchronization between the imaging pulses is non-trivial because microbubbles need to be interrogated in the compression and the rarefaction phase and the time-delay difference from dispersion has to be corrected. To address these issues, we propose the use of ultrafast radial modulation imaging (uRMI). In this technique, a beat frequency between the modulation pulse (around 1 MHz) and the ultrafast pulse-repetition frequency was exploited to separate microbubbles from tissue phantom in-vitro. This led to a modulated images set in the spectral domain of the slow-time that may then be demodulated through a digital lock-in amplifier to retrieve the contrast image. Ultrafast RMI, applied on a flow phantom with microbubbles, provided a contrast-to-tissue ratio from 7.2 to 14.8 dB at 15 MHz. For flow speed lower than 0.05 mL/min, uRMI (16 dB) provided a better contrast-to-tissue ratio than other techniques: SVD spatiotemporal filter (11 dB), amplitude modulation (9 dB) or microbubbles disruption (6 dB) or. This technique may then be suitable to improve the detection of targeted microbubbles, in ultrasound molecular imaging applications, and the detection of extremely slow microbubbles moving in the finest vessels in ultrasound localization microscopy

Economies of Scale in the Canadian Food Processing Industry

Cost functions for three Canadian manufacturing agri-food sectors (meat, bakery and dairy) are estimated using provincial data from 1990 to 1999. A translog functional form is used and the concavity property is imposed locally. The Morishima substitution elasticities and returns to scale elasticities are computed for different provinces. Inference is carried out using asymptotic theory as well as bootstrap methods. In particular, the ability of the double bootstrap to provide refinements in inference is investigated. The evidence suggests that there are significant substitution possibilities between the agricultural input and other production factors in the meat and bakery sectors. Scale elasticity parameters indicate that increasing returns to scale are present in small bakery industries. While point estimates suggest that increasing returns to scale exist at the industry level in the meat sector, statistical inference cannot rule the existence of decreasing returns to scale. To account for supply management in the dairy sector, separability between raw milk and the other inputs was introduced. There exists evidence of increasing returns to scale at the industry level in the dairy industries of Alberta and New Brunswick. The scale elasticity for the two largest provinces (Ontario and Quebec) is greater than one, but inference does not reject the null hypothesis of increasing returns to scale

Economies of Scale in the Canadian Food Processing Industry

Cost functions for three Canadian manufacturing agri-food sectors (meat, bakery and dairy) are estimated using provincial data from 1990 to 1999. A translog functional form is used and the concavity property is imposed locally. The Morishima substitution elasticities and returns to scale elasticities are computed for different provinces. Inference is carried out using asymptotic theory as well as bootstrap methods. In particular, the ability of the double bootstrap to provide refinements in inference is investigated. The evidence suggests that there are significant substitution possibilities between the agricultural input and other production factors in the meat and bakery sectors. Scale elasticity parameters indicate that increasing returns to scale are present in small bakery industries. While point estimates suggest that increasing returns to scale exist at the industry level in the meat sector, statistical inference cannot rule the existence of decreasing returns to scale. To account for supply management in the dairy sector, separability between raw milk and the other inputs was introduced. There exists evidence of increasing returns to scale at the industry level in the dairy industries of Alberta and New Brunswick. The scale elasticity for the two largest provinces (Ontario and Quebec) is greater than one, but inference does not reject the null hypothesis of increasing returns to scale

Echogenicity enhancement by end-fluorinated polylactide perfluorohexane nanocapsules: Towards ultrasound-activable nanosystems

International audienc

Differences in metabolomic and transcriptomic profiles between responders and non-responders to an n-3 polyunsaturated fatty acids (PUFAs) supplementation

Studies have demonstrated large within-population heterogeneity in plasma triacylglycerol (TG) response to n-3 PUFA supplementation. The objective of the study was to compare metabolomic and transcriptomic profiles of responders and non-responders of an n-3 PUFA supplementation. Thirty subjects completed a 2-week run-in period followed by a 6-week supplementation with n-3 PUFA (3 g/d). Six subjects did not lower their plasma TG (+9 %) levels (non-responders) and were matched to 6 subjects who lowered TG (−41 %) concentrations (responders) after the n-3 PUFA supplementation. Pre-n-3 PUFA supplementation characteristics did not differ between the non-responders and responders except for plasma glucose concentrations. In responders, changes were observed for plasma hexose concentrations, docosahexaenoic acid, stearoyl-CoA-desaturase-18 ratio, and the extent of saturation of glycerophosphatidylcholine after n-3 PUFA supplementation; however, no change in these parameters was observed in non-responders. Transcriptomic profiles after n-3 PUFA supplementation indicate changes in glycerophospholipid metabolism in both subgroups and sphingolipid metabolism in non-responders. Six key genes in lipid metabolism: fatty acid desaturase 2, phospholipase A2 group IVA, arachidonate 15-lipoxygenase, phosphatidylethanolamine N-methyltransferase, monoglyceride lipase, and glycerol-3-phosphate acyltransferase, were expressed in opposing direction between subgroups. In sum, results highlight key differences in lipid metabolism of non-responders compared to responders after an n-3 PUFA supplementation, which may explain the inter-individual variability in plasma TG response

Modeling the influence of eutrophication and redox conditions on mercury cycling at the sediment-water interface in the Berre Lagoon

This study presents a specifically designed Mercury module in a coupled benthic-pelagic reactive-transport model - Bottom RedOx Model (BROM) that allows to study mercury (Hg) biogeochemistry under different conditions. This module considers the transformation of elemental mercury (Hg(0)), divalent mercury (Hg(II)) and methylmercury (MeHg). The behavior of mercury species in the model is interconnected with changes of oxygen, hydrogen sulfide, iron oxides, organic matter, and biota. We simulated the transformation and transport of Hg species in the water column and upper sediment layer under five different scenarios, combining various levels of oxygenation and trophic state in the Berre lagoon, a shallow eutrophic lagoon of the French Mediterranean coast subjected to seasonal anoxia. The first scenario represents the conditions in the lagoon that are compared with experimental data. The four other scenarios were produced by varying the biological productivity, using low and high nutrient (N and P) concentrations, and by varying the redox conditions using different intensity of vertical mixing in the water column. The results of the simulation show that both oxidized and reduced sediments can accumulate Hg, but any shifts in redox conditions in bottom water and upper sediment layer lead to the release of Hg species into the water column. Eutrophication and/or restricted vertical mixing lead to reducing conditions and intensify MeHg formation in the sediment with periodic release to the water column. Oxygenation of an anoxic water body can lead to the appearance of Hg species in the water column and uptake by organisms, whereby Hg may enter into the food web. The comparison of studied scenarios shows that a well-oxygenated eutrophic system favors the conditions for Hg species bioaccumulation with a potential adverse effect on the ecosystem. The research is relevant to the UN Minimata convention, EU policies on water, environmental quality standards and Mercury in particular.publishedVersio

HLA-Class II Artificial Antigen Presenting Cells in CD4+ T Cell-Based Immunotherapy

CD4+ T cells differentiate into various T helper subsets characterized by distinct cytokine secreting profiles that confer them effector functions adapted to a variety of infectious or endogenous threats. Regulatory CD4+ T cells are another specialized subset that plays a fundamental role in the maintenance of immune tolerance to self-antigens. Manipulating effector or regulatory CD4+ T cells responses is a promising immunotherapy strategy for, respectively, chronical viral infections and cancer, or severe autoimmune diseases and transplantation. Adoptive cell therapy (ACT) is an emerging approach that necessitates defining robust and efficient methods for the in vitro expansion of antigen-specific T cells then infused into patients. To address this challenge, artificial antigen presenting cells (AAPCs) have been developed. They constitute a reliable and easily usable platform to stimulate and amplify antigen-specific CD4+ T cells. Here, we review the recent advances in understanding the functions of CD4+ T cells in immunity and in immune tolerance, and their use for ACT. We also describe the characteristics of different AAPC models and the way to improve their stimulating functions. Finally, we discuss the potential interest of these AAPCs, both as fundamental tools to decipher CD4+ T cell responses and as reagents to generate clinical grade antigen-specific CD4+ T cells for immunotherapy

A High-Quality Grapevine Downy Mildew Genome Assembly Reveals Rapidly Evolving and Lineage-Specific Putative Host Adaptation Genes

Downy mildews are obligate biotrophic oomycete pathogens that cause devastating plant diseases on economically important crops. Plasmopara viticola is the causal agent of grapevine downy mildew, a major disease in vineyards worldwide. We sequenced the genome of Pl. viticola with PacBio long reads and obtained a new 92.94 Mb assembly with high contiguity (359 scaffolds for a N50 of 706.5 kb) due to a better resolution of repeat regions. This assembly presented a high level of gene completeness, recovering 1,592 genes encoding secreted proteins involved in plant–pathogen interactions. Plasmopara viticola had a two-speed genome architecture, with secreted protein-encoding genes preferentially located in gene-sparse, repeat-rich regions and evolving rapidly, as indicated by pairwise dN/dS values. We also used short reads to assemble the genome of Plasmopara muralis, a closely related species infecting grape ivy (Parthenocissus tricuspidata). The lineage-specific proteins identified by comparative genomics analysis included a large proportion of RxLR cytoplasmic effectors and, more generally, genes with high dN/dS values. We identified 270 candidate genes under positive selection, including several genes encoding transporters and components of the RNA machinery potentially involved in host specialization. Finally, the Pl. viticola genome assembly generated here will allow the development of robust population genomics approaches for investigating the mechanisms involved in adaptation to biotic and abiotic selective pressures in this species