Cumulative Effects of Watershed Disturbances and Run-of-river Dams on Mercury Cycling: Case Study and Recommendations for Environmental Managers.

Run-of-river power plants (ROR) represent the majority of hydroelectric plants worldwide. Their environmental impacts are not well documented and are believed to be limited, particularly regarding the contamination of food webs by methylmercury (MeHg), a neurotoxin. RORs are typically installed in small rivers where combined effects of watershed disturbances with dam construction can complicate environmental management. We report a multi-year case study on the Saint-Maurice River (Canada) where an unpredicted temporary increase in MeHg accumulation in predator fish was observed after the construction of two ROR plants. The associated pondages acted as sedimentation basins for mercury (Hg) and organic matter from a watershed disturbed by a forest fire and by logging. This fresh organic carbon likely fueled microbial MeHg production. Hg methylation was more associated with environmental conditions than to the presence of Hg, and main methylating microbial groups were identified. A constructed wetland was a site of significant Hg methylation but was not the main source of the fish Hg increase. Organic carbon degradation was the main driver of MeHg accumulation at the base of the food chain whereas trophic levels explained the variations at the top of the food chain. Overall, carbon cycling was a key driver of Hg dynamics in this system, and ROR plants can cause temporary (ca. 12 years) Hg increase in food webs when developed in disturbed watersheds, although this increase is smaller than for large reservoirs. Recommendations for future ROR construction are to establish a good environmental monitoring plan with initial high temporal resolution and to consider recent and potential watershed disturbances in the plan.

Assessment of pixel-oriented k-NN machine learning algorithm performance for the interannual remote sensing monitoring of eelgrass beds at the mouth of the Romaine.

Eelgrass cover extent is among the most reliable indicators for measuring changes in coastal ecosystems. Eelgrass has colonized the mouth of the Romaine River and has become a part of environmental monitoring there since 2013. The presence of eelgrass in this area is an essential factor for the early detection of changes in the Romaine coastal ecosystem. This will act as a trigger for an appropriate environmental response to preserve ecosystem health. In this paper, a cost- and time-efficient workflow for such spatial monitoring is proposed using a pixel-oriented k-NN algorithm. It can then be applied to multiple modellers to efficiently map the eelgrass cover. Training data were collected to define key variables for segmentation and k-NN classification, providing greater edge detection for the presence of eelgrass. The study highlights that remote sensing and training data must be acquired under similar conditions, replicating methodologies for collecting data on the ground. Similar approaches must be used for the zonal statistic requirements of the monitoring area. This will allow a more accurate and reliable assessment of eelgrass beds over time. An overall accuracy of over 90% was achieved for eelgrass detection for each year of monitoring.

Resilient Fermi Liquid and Strength of Correlations near an Antiferromagnetic Quantum Critical Point.

Near the antiferromagnetic quantum critical point (QCP) of electron-doped cuprate superconductors, angle-resolved photoemission experiments detect hot spots where the Fermi surface disappears. Here, we demonstrate, using the two-particle self-consistent theory, that in the antinodal region the Fermi liquid remains stable for a broad range of angles on the Fermi surface and for all dopings near the QCP. We show how the quasiparticle weight Z and effective mass m^{*} change and then abruptly become meaningless as the hot spots are approached. We propose a dimensionless number, easily accessible in ARPES experiments, that can be used to gauge the strength of correlations.

A systematic review of the use of the Satiety Quotient.

The satiating efficiency of food has been increasingly quantified using the Satiety Quotient (SQ). The SQ integrates both the energy content of food ingested during a meal and the associated change in appetite sensations. This systematic review examines the available evidence regarding its methodological use and clinical utility. A literature search was conducted in six databases considering studies from 1900 to April 2020 that used SQ in adults, adolescents and children. All study designs were included. From the initial 495 references found, fifty-two were included. Of the studies included, thirty-three were acute studies (twenty-nine in adults and four in adolescents) and nineteen were longitudinal studies in adults. A high methodological heterogeneity in the application of the SQ was observed between studies. Five main utilisations of the SQ were identified: its association with (i) energy intake; (ii) anthropometric variables; (iii) energy expenditure/physical activity; (iv) sleep quality and quantity and (v) to classify individuals by their satiety responsiveness (i.e. low and high satiety phenotypes). Altogether, the studies suggest the SQ as an interesting clinical tool regarding the satiety responsiveness to a meal and its changes in responses to weight loss in adults. The SQ might be a reliable clinical indicator in adults when it comes to both obesity prevention and treatment. There is a need for more standardised use of the SQ in addition to further studies to investigate its validity in different contexts and populations, especially among children and adolescents.

Physical Activity and Sedentary Behavior of Elderly Populations during Confinement: Results from the FRENCH COVID-19 ONAPS Survey.

Introduction: A national confinement was imposed in France in March 2020 during 55 days to prevent the spread of the virus and protect vulnerable people such as older individuals. This study aimed to describe the movement behaviors, and their determinants, of elderly people (≥ 65 years) during the confinement.Methods: An online survey was conducted from April 1st, 2020 to May 6th, 2020 by the National Observatory for Physical Activity and Sedentary behaviors. This study compared the level of physical activity (PA), sitting and screen time before and during the confinement and identified the impact of initial PA, sedentary profiles of the participants and housing conditions.Results: 1,178 people were included in this study. Reaching PA recommendations before lock-down was associated with the change in PA level during lock-down (p < .001). Besides, geographic location was associated with the change in PA, sitting time and screen time during lock-down (respectively p = .03, p = .02, p = .02).Conclusion: This study confirm the negative impact of confinement on senior movement behaviors, whether or not they met with public health recommendations prior to the pandemic. The housing conditions of older people must be also taken into future public health policies.

Satiety responsiveness but not food reward is modified in response to an acute bout of low versus high intensity exercise in healthy adults.

To compare the effect of iso-caloric low and high intensity exercises on Satiety Quotient and Food Reward in response to a fixed meal in healthy young adults. Anthropometric measurements, body composition (BIA), aerobic capacity (VO2 max) and food preferences were assessed in 19 healthy normal-weight young adults (21 ±â€¯0.5 years old, 10 men). They randomly completed 3 experimental sessions: i) control session without exercise (CON); ii) High Intensity exercise session (HIE); iii) Low intensity exercise session (LIE). Thirty minutes after exercise or rest, then received a fixed lunch. Food reward (Leeds Food Preference Questionnaire) was assessed before and after the meal. Appetite sensations were assessed at regular intervals, SQ was calculated from the lunch meal and self-reported food intake was collected for the rest of the day. Mean body weight was 66.7 ±â€¯9.2 kg, body mass index was 22.3 ±â€¯2.9 kg/m2 and FM% was 18.7 ±â€¯6.8%. Appetite feelings did not differ between conditions and were not affected by exercise. SQ for satiety was not different between conditions. SQ hunger on CON was significantly higher than on LIE and HIE (p ≤ 0.05) with no difference between exercise conditions. SQ for desire to eat was significantly higher on CON versus HIE (p ≤ 0.01) with no differences between CON and LIE and between exercise sessions. SQ PFC was significantly lower on HIE compared with CON (p = 0.02) with no differences between LIE and CON and between LIE and HIE. Food reward was not significantly different between the three condition as well as self-reported total food and macronutrient intake for the rest of the days. Acute exercise, depending on its intensity, might affect the satiating response to food intake in healthy adults, without altering food reward.

Superconducting Symmetries of Sr_{2}RuO_{4} from First-Principles Electronic Structure.

Although correlated electronic-structure calculations explain very well the normal state of Sr_{2}RuO_{4}, its superconducting symmetry is still unknown. Here we construct the spin and charge fluctuation pairing interactions based on its correlated normal state. Correlations significantly reduce ferromagnetic in favor of antiferromagnetic fluctuations and increase interorbital pairing. From the normal-state Eliashberg equations, we find spin-singlet d-wave pairing close to magnetic instabilities. Away from these instabilities, where charge fluctuations increase, we find two time-reversal symmetry-breaking spin triplets: an odd-frequency s wave, and a doubly degenerate interorbital pairing between d_{xy} and (d_{yz},d_{xz}).

Local Entanglement Entropy and Mutual Information across the Mott Transition in the Two-Dimensional Hubbard Model.

Entanglement and information are powerful lenses to probe phases transitions in many-body systems. Motivated by recent cold atom experiments, which are now able to measure the corresponding information-theoretic quantities, we study the Mott transition in the half-filled two-dimensional Hubbard model using cellular dynamical mean-field theory, and focus on two key measures of quantum correlations: entanglement entropy and a measure of total mutual information. We show that they detect the first-order nature of the transition, the universality class of the end point, and the crossover emanating from the end point.

The expression of NTPDase1 and -2 of Leishmania infantum chagasi in bacterial and mammalian cells: Comparative expression, refolding and nucleotidase characterization.

Visceral Leishmaniasis (VL) represents an important global health problem in several warm countries around the world. The main targets in this study are the two nucleoside triphosphate diphosphohydrolases (NTPDases) from Leishmania infantum chagasi that are the main etiologic agent of VL in the New World. These enzymes, called LicNTPDase1 and -2, are homologous to members 5 and 6 of the mammalian E-NTPDase/CD39 superfamily of enzymes. These enzymes hydrolyze nucleotides and accordingly can participate in the purine salvage pathways and in the modulation of purinergic signaling through the extracellular nucleotide-dependent host immune responses. They can therefore affect adhesion and infection of host cells and the parasite virulence. To further characterize these enzymes, in this work, we expressed LicNTPDase1 and -2 in the classical bacterial system Escherichia coli and mammalian cell system COS-7 cells. Our data demonstrate that changes in refolding after expression in bacteria can increase the activity of recombinant (r) rLicNTPDase2 up to 20 times but has no significant effect on rLicNTPDase1. Meanwhile, the expression in COS-7 led to a significant increase in activity for rLicNTPDase1.

Mechanical efficiency in children with different body weight: a longitudinal assessment of the quality cohort.

Net mechanical efficiency (MEnet), which reflects the body's ability to transfer energy above resting levels in external work, is similar in young children regardless of their body weights. However, it is unclear whether MEnet remains stable during growth and maturation. We sought to determine whether net mechanical efficiency (MEnet) changes over a period of 3 years in children and to identify the factors associated with possible changes. A total of 169 children participating in the QUALITY (Quebec Adipose and Lifestyle InvesTigation in Youth) cohort completed an incremental cycling test, resulting in the same maximal power output during both visits. For MEnet, resting energy consumption was subtracted from total energy consumption at each exercise stage. Physical activity was measured using an accelerometer worn for 7 days. Participants were measured at year one and again two years later. MEnet did not differ across the visits at the 25, 50 and 75 watt stages. However, the participants exhibited lower MEnet values at follow-up for the 100 and 125 W stages (23(3) vs. 20(1)%; 25(4) vs. 20(2)%; p<0.01). Declines in MEnet correlated positively with declines in moderate-to-vigorous physical activity levels (r=0.78, p<0.05). The declines in moderate-to-vigorous physical activity levels across the visits were identified as significant predictors of MEnet changes at 100 and 125 W over 3 years, accounting for 22% of the relationship. In children, MEnet, determined at high exercise intensity, decreases within a period of three years, and the decrement appeared to be related to moderate-to-vigorous physical activity.

Capsaicinoids: a spicy solution to the management of obesity?

Capsaicin is the molecule that is responsible for the pungency of hot peppers. It stimulates the sympathoadrenal system that mediates the thermogenic and anorexigenic effects of capsaicinoids. Capsaicinoids have been found to accentuate the impact of caloric restriction on body weight loss. Some studies have also shown that capsinoids, the non-pungent analogs of capsaicinoids, increase energy expenditure. Capsaicin supplementation attenuates or even prevents the increase in hunger and decrease in fullness as well as the decrease in energy expenditure and fat oxidation, which normally result from energy restriction. These effects may postpone the occurrence of resistance to lose fat during a weight loss program and facilitate the maintenance of body weight in a postobese state. Evidence also highlights the plausibility of an indirect effect of capsaicin on energy balance via its analgesic effects, which may improve sleep and ultimately facilitate the regulation of energy balance. Although capsaicin intake appears to be a safe practice, further studies will be needed to ascertain the safety of regular long-term consumption. Taken together, these observations reinforce the idea that consumption of capsaicinoids and capsinoids may be helpful to facilitate obesity management.

Correlation-Enhanced Odd-Parity Interorbital Singlet Pairing in the Iron-Pnictide Superconductor LiFeAs.

The rich variety of iron-based superconductors and their complex electronic structure lead to a wide range of possibilities for gap symmetry and pairing components. Here we solve in the two-Fe Brillouin zone the full frequency-dependent linearized Eliashberg equations to investigate spin-fluctuations mediated Cooper pairing for LiFeAs. The magnetic excitations are calculated with the random phase approximation on a correlated electronic structure obtained with density functional theory and dynamical mean field theory. The interaction between electrons through Hund's coupling promotes both the intraorbital d_{xz(yz)} and the interorbital magnetic susceptibility. As a consequence, the leading pairing channel, conventional s^{+-}, acquires sizable interorbital d_{xy}-d_{xz(yz)} singlet pairing with odd parity under glide-plane symmetry. The combination of intra- and interorbital components makes the results consistent with available experiments on the angular dependence of the gaps observed on the different Fermi surfaces.

Food intake response to exercise and active video gaming in adolescents: effect of weight status.

Although a few data are available regarding the impact of video games on energy intake (EI) in lean adolescents, there is no evidence on the effect of passive and active video gaming on food intake in both lean and obese youth. It is also unknown whether isoenergetic active video games and exercise differently affect food consumption in youth. In all, twelve lean and twelve obese adolescent boys (12-15 years old) had to complete four 1-h sessions in a cross-over design study: control (CON; sitting), passive video game (PVG; boxing game on Xbox 360), active video game (AVG; boxing game on Xbox Kinect 360) and exercise (EX; cycling). The exercise and active video game activities were designed to generate the same energy expenditure (EE). EE was measured using a K4b2 portable indirect calorimeter. Ad libitum food intake and appetite sensations were assessed following the sessions. AVG and EX-EE were significantly higher in obese participants and significantly higher compared with PVG and CON in both groups. Obese participants significantly ate more than lean ones in all four conditions (P<0·001). EI did not differ between conditions in obese participants (CON: 4935 (SD 1490) kJ; PVG: 4902 (SD 1307) kJ; AVG: 4728 (SD 1358) kJ; EX: 4643 (SD 1335) kJ), and was significantly lower in lean participants after EX (2847 (SD 577) kJ) compared with PVG (3580 (SD 863) kJ) and AVG (3485 (SD 643) kJ) (P<0·05). Macronutrient intake was not significantly different between the groups or conditions. Hunger was significantly higher and satiety was lower in obese participants but no condition effect was observed. Overall, moderate-intensity exercise provides better effect on energy balance than an isoenergetic hour of active video gaming in lean adolescent boys by dually affecting EE and EI.

Night-eating symptoms and 2-year weight change in parents enrolled in the QUALITY cohort.

BACKGROUND/OBJECTIVE: The timing of food intake may be implicated in weight gain. This study tested the hypothesis that symptoms commonly associated with night-eating syndrome are related to measures of weight gain in adults. SUBJECTS/METHODS: Parents participating in QUALITY (Québec Adipose and Lifestyle InvesTigation in Youth) completed the night eating questionnaire (NEQ) at baseline (2005-2008) and at follow-up (2008-2010). Height and weight were measured and self-report questionnaire data were available for 388 parents (59% female, mean (s.d.) age: 41.8±5.7, mean (s.d.) body mass index (BMI): 29.6±5.7). Linear regression models were used to test the associations between baseline night-eating symptoms (NEQ scores, night-eating behaviours) and percent change in each of BMI and waist circumference (WC). RESULTS: A high NEQ score predicted a small increase in percent change in BMI in nonobese parents but a decrease among those who were severely obese. Nocturnal ingestions of food predicted an increase in percent change in BMI; however, the effect size was small. Morning anorexia predicted an increase in percent change in WC. CONCLUSION: Certain night-eating symptoms may predict measures of weight gain in adults but the effects seem small and the findings need to be confirmed in more symptomatic samples.

Effect of adipose tissue volume loss on circulating 25-hydroxyvitamin D levels: results from a 1-year lifestyle intervention in viscerally obese men.

BACKGROUND/OBJECTIVES: Although weight loss has been associated with changes in circulating 25-hydroxyvitamin D (25(OH)D) levels, the quantification of the increase in 25(OH)D levels as a function of adipose tissue volume loss precisely assessed by imaging has not been reported before. The objective of this substudy was to describe the effects of a 1-year lifestyle intervention on plasma 25(OH)D levels. The relationships between changes in 25(OH)D levels and changes in adiposity volume (total and by adipose tissue compartment) were studied. SUBJECTS/METHODS: This intervention study was performed between 2004 and 2006 and participants were recruited from the general community. Sedentary, abdominally obese and dyslipidemic men (n=103) were involved in a 1-year lifestyle modification program. Subjects were individually counseled by a kinesiologist and a nutritionist once every 2 weeks during the first 4 months with subsequent monthly visits in order to elicit a 500-kcal daily energy deficit and to increase physical activity/exercise habits. Body weight, body composition and fat distribution were assessed by dual-energy X-ray absorptiometry and computed tomography, whereas the 25(OH)D levels were measured with an automated assay. RESULTS: The 1-year intervention resulted in a 26% increase in circulating 25(OH)D (from 48±2 nmol l(-1) or 19±0.8 ng ml(-1) (±s.e.m.) to 58±2 nmol l(-1) or 23±0.8 ng ml(-1), P<0.0001) along with a 26% decrease in visceral adiposity volume (from 1947±458 to 1459±532 cm3). One-year increases in 25(OH)D levels correlated inversely with changes in all adiposity indices, especially Δvisceral (r=-0.36, P<0.0005) and Δtotal abdominal (r=-0.37, P<0.0005) adipose tissue volumes. CONCLUSIONS: These results indicate that there is a linear increase in circulating 25(OH)D levels as a function of adiposity volume loss, and therefore suggest a role of adiposity reduction in the management of obesity-associated vitamin D insufficiency.

Prevalence of risk factors for cardiovascular disease in paramedics.

PURPOSE: Occupational stress and obesity are very prevalent in emergency workers. Some studies have also associated high tobacco consumption rates with occupational stress. Each of these factors is known to increase cardiovascular risk. The aim of this study was to evaluate the prevalence of occupational stress, overweight and tobacco consumption in paramedics. METHODS: This cross-sectional study of paramedics consisted in a self-report survey of 44 questions divided into two sections. The first section collected demographic information and the second evaluated occupational stressors. The questions were designed to determine the prevalence of work-related psychosocial factors, overweight (body mass index ≥ 25 kg/m(2)) and tobacco consumption (cig/day ≥ 1). The demand-control-social support model and the effort-reward model were used to estimate job strain, iso-strain and imbalance in effort and reward. RESULTS: More than 88 % of paramedics reported at least one cardiovascular risk factor, with males reporting more risk factors than females. Ninety percent of male paramedics reported occupational stress, 12 % reported smoking, and 79 % were overweight or obese by self-report. The prevalence of occupational stress and smoking was similar for female paramedics, but with a lower prevalence of overweight (37 %). CONCLUSION: By self-report, nine out of ten paramedics are at risk of developing cardiovascular disease. Both individual and organizational efforts should be made to educate and support paramedics and their organizations in reducing these workers' cardiovascular risk.

Predictors of body composition and body energy changes in response to chronic overfeeding.

OBJECTIVE: We have previously shown that 24 young lean men (12 pairs of identical twins) subjected to a standardized 353 MJ (84 000 kcal) overfeeding protocol over 100 days exhibited individual differences in body weight and composition gains. The mean (+s.d.) gains in fat mass (FM) and fat-free mass (FFM) were 5.4+1.9 kg and 2.7+1.5 kg for a total body energy (BE) gain of 221+75 MJ, representing 63% of the energy surplus consumed. We report here on the most important baseline correlates of these overfeeding-induced changes with the aim of identifying biomarkers of the response. RESULTS: Baseline maximal oxygen uptake per kg body mass was negatively correlated with gains in weight, FM and BE (all P<0.05). Enzyme activities indicative of skeletal muscle oxidative potential correlated with gains in FM and BE (all P<0.05). Baseline thyroid-stimulating hormone levels in response to thyrotropin-releasing hormone stimulation correlated positively with changes in FM-to-FFM ratio (P<0.05). Plasma concentrations of androstenediol sulfate, dehydroepiandrosterone and 17-hydroxy pregnenolone were negatively correlated with gains in FM and BE (0.01

Effect of sitagliptin therapy on triglyceride-rich lipoprotein kinetics in patients with type 2 diabetes.

AIM: To investigate the effects of sitagliptin therapy on the kinetics of triglyceride-rich lipoprotein (TRL) apolipoprotein (apo)B-48, VLDL apoB-100, apoE and apoC-III in patients with type 2 diabetes. METHODS: Twenty-two subjects with type 2 diabetes were recruited in this double-blind crossover study, during which the subjects received sitagliptin (100 mg/day) or placebo for a 6-week period each. At the end of each phase of treatment, the in vivo kinetics of the different apolipoproteins were assessed using a primed-constant infusion of l-[5,5,5-D3]leucine for 12 h, with the participants in a constantly fed state. RESULTS: Sitagliptin therapy significantly reduced fasting plasma triglyceride (-15.4%, p = 0.03), apoB-48 (-16.3%, p = 0.03) and free fatty acid concentrations (-9.5%, p = 0.04), as well as plasma HbA1c (placebo: 7.0% ± 0.8 vs. sitagliptin: 6.6% ± 0.7, p < 0.0001) and plasma glucose levels (-13.5%, p = 0.001), without any significant effect on insulin levels. Kinetic results showed that treatment with sitagliptin significantly reduced the pool size of TRL apoB-48 by -20.8% (p = 0.03), paralleled by a reduction in the production rate of these particles (-16.0%, p = 0.03). The VLDL apoB-100 pool size was also significantly decreased by sitagliptin therapy (-9.3%, p = 0.03), mainly because of a reduction in the hepatic secretion of these lipoproteins, although this difference did not reach statistical significance (-9.2%, p = 0.06). CONCLUSIONS: Treatment with sitagliptin for 6 weeks reduced triglyceride-rich apoB-containing lipoprotein levels by reducing the synthesis of these particles.

Adaptive thermogenesis can make a difference in the ability of obese individuals to lose body weight.

The decrease in energy expenditure that occurs during weight loss is a process that attenuates over time the impact of a restrictive diet on energy balance up to a point beyond which no further weight loss seems to be possible. For some health professionals, such a diminished energy expenditure is the normal consequence of a progressive decrease in the motivation to exercise over the course of a weight-reducing program. Another explanation of decreased energy needs during weight loss is the decrease in body energy stores (that is, fat mass and muscle mass) and its related obligatory costs of living. Many studies have also documented the existence of adaptive thermogenesis in the context of weight loss, which represents a greater-than-predicted decrease in energy expenditure. In this paper, we pursue the analysis of this phenomenon by demonstrating that an adaptive decrease in thermogenesis can have a major role in the occurrence of resistance to further lose fat in weight-reduced obese individuals. Evidence is also presented to support the idea of greater hunger sensations in individuals displaying more pronounced thermogenic changes. Finally, as the decrease in thermogenesis persists over time, it is also likely associated with a greater predisposition to body-weight regain after weight loss. Globally, these observations suggest that the adaptive reduction in thermogenesis that accompanies a prolonged negative energy balance is a major determinant of the ability to spontaneously lose body fat.

Parental eating behavior traits are related to offspring BMI in the Québec Family Study.

OBJECTIVE: Parental eating behavior traits have been shown to be related to the adiposity of their young children. It is unknown whether this relationship persists in older offspring or whether rigid or flexible control are involved. The objective of this study was to test the hypothesis that parental eating behavior traits, as measured by the Three-Factor Eating Questionnaire (TFEQ), are related to offspring body weight. METHODS: Cross-sectional anthropometric and TFEQ data from phase 2 and 3 of the Québec Family Study generated 192 parent-offspring dyads (offspring age range: 10-37 years). Relationships were adjusted for offspring age, sex and reported physical activity, number of offspring per family and parent body mass index (BMI). RESULTS: In all parent-offspring dyads, parental rigid control and disinhibition scores were positively related to offspring BMI (r=0.17, P=0.02; r=0.18, P<0.01, respectively). There were no significant relationships between cognitive restraint (P=0.75) or flexible control (P=0.06) with offspring BMI. Regression models revealed that parent disinhibition mediated the relationship between parent and offspring BMI, whereas rigid control of the parent moderated this relationship. The interaction effect between parental rigid control and disinhibition was a significant predictor of offspring BMI (ß=0.13, P=0.05). CONCLUSION: Family environmental factors, such as parental eating behavior traits, are related to BMI of older offspring, and should be a focus in the prevention of obesity transmission within families.