Quantization codebook optimization for color image under psychophysical constraints

The information contained into an image is spatially, spectrally and perceptually redundant . In the context of the color Vector Quantization (VQ) compression scheme, this redundancy is a handicap in terms of performances (complexity, quality and compression rate) . Combining perceptual and classification criteria, one can improve the codebook quality when reduce construction time associated . In this paper, we propose a training set reduction method . Associating to vectors of the training set a perceptually relevant measure, one can extract a subset from it . A classification step is then applied on this subset . Finally, the codebook is construct using the LBG algorithm on each obtained cluster, and joining together all code vectors . Psychophysics and statistical measures of image quality allow us to validate our method in terms of construction time, reconstructed image quality and compression rate .L'information contenue dans une image couleur est redondante spatialement, spectralement et perceptuellement. Dans le contexte de la compression d'image couleur par quantification vectorielle, cette redondance devient rapidement un handicap en termes de performances (complexité, qualité, taux de compression). En combinant des éléments de perception et de classification, il est possible d'améliorer la qualité du dictionnaire tout en réduisant le temps de construction associé. Dans cet article, nous proposons une méthode de réduction de la base d'apprentissage. En associant aux éléments de cette base une mesure perceptuellement significative, nous en extrayons un sous-ensemble représentatif. Une étape de classification reposant sur un modèle paramétrique de la mesure est ensuite appliquée sur ce sous-ensemble. Pour chacune des classes obtenues, un dictionnaire est déterminé en appliquant l'algorithme LBG. L'ensemble de ces dictionnaires constitue le dictionnaire final. L'utilisation de tests psychophysiques et de mesures statistiques de la qualité nous ont permis de valider notre approche en termes de temps de calcul, de qualité des images reconstruites et du taux de compression

Residual contamination detection and serovar distribution of Listeria monocytogenes isolates in pork slaughterhouse and cutting facilities in province of Quebec

L. monocytogenes (L. mono) is recognised as a zoonotic foodborne pathogen. Its control is focused on the “Readyto Eat” food production level. Recently, Health Canada had reinforced its “Policy on L. mono in Ready-to-Eat Foods”, highlighting environmental surveillance and control of meat processing facilities as important risk reduction tools. The industry wants to improve its management of L. mono risk, taking into account previous steps of meat production. Nowadays, few information are available on the presence, distribution and types of strains in the environments concerning this pathogen in pork slaughterhouses and cutting facilities in Canada. Our objective was to detect and described residual L. mono contamination and analyse serovars distribution in different areas in the pork production continuum in and between slaughterhouses and cutting facilities in province of Quebec, during a one year period. Such data are a pre-requisite to achieve the optimization of the management measures by the industrials

Exchange bias in GeMn nanocolumns: the role of surface oxidation

We report on the exchange biasing of self-assembled ferromagnetic GeMn nanocolumns by GeMn-oxide caps. The x-ray absorption spectroscopy analysis of this surface oxide shows a multiplet fine structure that is typical of the Mn2+ valence state in MnO. A magnetization hysteresis shift |HE|~100 Oe and a coercivity enhancement of about 70 Oe have been obtained upon cooling (300-5 K) in a magnetic field as low as 0.25 T. This exchange bias is attributed to the interface coupling between the ferromagnetic nanocolumns and the antiferromagnetic MnO-like caps. The effect enhancement is achieved by depositing a MnO layer on the GeMn nanocolumns.Comment: 7 pages, 5 figure

Topological Monomodes in non-Hermitian Systems

Topological monomodes have been for long as elusive as magnetic monopoles. The latter was experimentally shown to emerge in effective descriptions of condensed-matter systems, while the experimental exploration of the former has largely been hindered by the complexity of the conceived setups. Here, we present a remarkably simple model and the experimental observation of topological monomodes generated dynamically. By focusing on non-Hermitian one-dimensional (1D) and 2D Su-Schrieffer-Heeger (SSH) models, we theoretically unveil the minimal configuration to realize a topological monomode upon engineering losses and breaking of lattice symmetries. Furthermore, we classify the systems in terms of the (non-Hermitian) symmetries that are present and calculate the corresponding topological invariants. To corroborate the theory, we present experiments in photonic lattices, in which a monomode is observed in the non-Hermitian 1D and 2D SSH models, thus breaking the paradigm that topological corner states should appear in pairs. Our findings might have profound implications for photonics and quantum optics because topological monomodes increase the robustness of corner states by preventing recombination.Comment: 30 (13+17) pages, 17 (4+13) figures, comments are welcom

High Compared with Moderate Protein Intake Reduces Adaptive Thermogenesis and Induces a Negative Energy Balance during Long-term Weight-Loss Maintenance in Participants with Prediabetes in the Postobese State : A PREVIEW Study

Background: Weight loss has been associated with adaptations in energy expenditure. Identifying factors that counteract these adaptations are important for long-term weight loss and weight maintenance. Objective: The aim of this study was to investigate whether increased protein/carbohydrate ratio would reduce adaptive thermogenesis (AT) and the expected positive energy balance (EB) during weight maintenance after weight loss in participants with prediabetes in the postobese state. Methods: In 38 participants, the effects of 2 diets differing in protein/carbohydrate ratio on energy expenditure and respiratory quotient (RQ) were assessed during 48-h respiration chamber measurements similar to 34 mo after weight loss. Participants consumed a high-protein (HP) diet In = 20; 13 women/7 men; age: 64.0 +/- 6.2 y; BMI: 28.9 +/- 4.0 kg/m(2)) with 25:45:30% or a moderate-protein (MP) diet (n = 18; 9 women/9 men; age: 65.1 +/- 5.8 y; BMI: 29.0 +/- 3.8 kg/m(2)) with 15:55:30% of energy from protein:carbohydrate:fat. Predicted resting energy expenditure (REEp) was calculated based on fat-free mass and fat mass. AT was assessed by subtracting measured resting energy expenditure (REE) from REEp. The main outcomes included differences in components of energy expenditure, substrate oxidation, and AT between groups. Results: EB (MP = 0.2 +/- 0.9 MJ/d; HP = -0.5 +/- 0.9 MJ/d) and RO (MP = 0.84 +/- 0.02; HP = 0.82 +/- 0.02) were reduced and REE (MP: 73 +/- 0.2 MJ/d compared with HP: 78 +/- 0.2 MJ/d) was increased in the HP group compared with the MP group (P <0.05). REE was not different from REEp in the HP group, whereas REE was lower than REEp in the MP group (P <0.05). Furthermore, EB was positively related to AT (r(s) = 0.74; P <0.001) and RQ (r(s) = 0.47; P <0.01) in the whole group of participants. Conclusions: In conclusion, an HP diet compared with an MP diet led to a negative EB and counteracted AT similar to 34 mo after weight loss, in participants with prediabetes in the postobese state. These results indicate the relevance of compliance to an increased protein/carbohydrate ratio for long-term weight maintenance after weight loss.Peer reviewe

Tunnel magnetoresistance and robust room temperature exchange bias with multiferroic BiFeO3 epitaxial thin films

We report on the functionalization of multiferroic BiFeO3 epitaxial films for spintronics. A first example is provided by the use of ultrathin layers of BiFeO3 as tunnel barriers in magnetic tunnel junctions with La2/3Sr1/3MnO3 and Co electrodes. In such structures, a positive tunnel magnetoresistance up to 30% is obtained at low temperature. A second example is the exploitation of the antiferromagnetic spin structure of a BiFeO3 film to induce a sizeable (~60 Oe) exchange bias on a ferromagnetic film of CoFeB, at room temperature. Remarkably, the exchange bias effect is robust upon magnetic field cycling, with no indications of training.Comment: 15 pages, 4 figure

Effects of a High-Protein Diet on Cardiometabolic Health, Vascular Function, and Endocannabinoids-A PREVIEW Study

An unfavorable lipid profile and being overweight are known mediators in the development of cardiovascular disease (CVD) risk. The effect of diet, particularly high in protein, remains under discussion. Therefore, this study examines the effects of a high-protein (HP) diet on cardiometabolic health and vascular function (i.e., endothelial function, arterial stiffness, and retinal microvascular structure), and the possible association with plasma endocannabinoids and endocannabinoid-related compounds in overweight participants. Thirty-eight participants (64.5 +/- 5.9 (mean +/- SD) years; body mass index (BMI) 28.9 +/- 4.0 kg/m(2)) were measured for 48 h in a respiration chamber after body-weight maintenance for approximately 34 months following weight reduction. Diets with either a HP (n= 20) or moderate protein (MP;n= 18) content (25%/45%/30% vs. 15%/55%/30% protein/carbohydrate/fat) were provided in energy balance. Validated markers for cardiometabolic health (i.e., office blood pressure (BP) and serum lipoprotein concentrations) and vascular function (i.e., brachial artery flow-mediated vasodilation, pulse wave analysis and velocity, and retinal microvascular calibers) were measured before and after those 48 h. Additionally, 24 h ambulatory BP, plasma anandamide (AEA), 2-arachidonoylglycerol (2-AG), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and pregnenolone (PREG) were analyzed throughout the day. Office and ambulatory BP, serum lipoprotein concentrations, and vascular function markers were not different between the groups. Only heart rate (HR) was higher in the HP group. HR was positively associated with OEA, while OEA and PEA were also positively associated with total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol concentrations. Vascular function markers were not associated with endocannabinoids (or endocannabinoid-related substances). In conclusion, the HP diet did not affect cardiometabolic health and vascular function in overweight participants after completing a weight-loss intervention. Furthermore, our data indicate a possible association between OEA and PEA with TC and LDL cholesterol.Peer reviewe

Effects of a High-Protein Diet on Cardiometabolic Health, Vascular Function, and Endocannabinoids—A PREVIEW Study

An unfavorable lipid profile and being overweight are known mediators in the development of cardiovascular disease (CVD) risk. The effect of diet, particularly high in protein, remains under discussion. Therefore, this study examines the effects of a high-protein (HP) diet on cardiometabolic health and vascular function (i.e., endothelial function, arterial stiffness, and retinal microvascular structure), and the possible association with plasma endocannabinoids and endocannabinoid-related compounds in overweight participants. Thirty-eight participants (64.5 ± 5.9 (mean ± SD) years; body mass index (BMI) 28.9 ± 4.0 kg/m2) were measured for 48 h in a respiration chamber after body-weight maintenance for approximately 34 months following weight reduction. Diets with either a HP (n = 20) or moderate protein (MP; n = 18) content (25%/45%/30% vs. 15%/55%/30% protein/carbohydrate/fat) were provided in energy balance. Validated markers for cardiometabolic health (i.e., office blood pressure (BP) and serum lipoprotein concentrations) and vascular function (i.e., brachial artery flow-mediated vasodilation, pulse wave analysis and velocity, and retinal microvascular calibers) were measured before and after those 48 h. Additionally, 24 h ambulatory BP, plasma anandamide (AEA), 2-arachidonoylglycerol (2-AG), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and pregnenolone (PREG) were analyzed throughout the day. Office and ambulatory BP, serum lipoprotein concentrations, and vascular function markers were not different between the groups. Only heart rate (HR) was higher in the HP group. HR was positively associated with OEA, while OEA and PEA were also positively associated with total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol concentrations. Vascular function markers were not associated with endocannabinoids (or endocannabinoid-related substances). In conclusion, the HP diet did not affect cardiometabolic health and vascular function in overweight participants after completing a weight-loss intervention. Furthermore, our data indicate a possible association between OEA and PEA with TC and LDL cholesterol