Modeling the effect of temperature-control curtain on the thermal structure in a deep stratified reservoir.

Temperature-control curtain (TCC) is an effective facility of selective withdrawal. Previous research has estimated the influence of TCC on the outflow temperature, but its effect on the thermal structure of a reservoir area is unknown, which is crucial to the reservoir ecology. For this purpose, taking the Sanbanxi Reservoir as a case study, a 2-D hydrodynamic and temperature model covering the whole reservoir was built and calibrated to simulate the flow and temperature fields under different TCC scenarios, and the change rules of thermal stability and outflow temperature are obtained. When the water-retaining proportion (Pr) of bottom-TCC increases, the temperature difference between inflow and outflow monotonously decreases, while the thermal stability first increases and later decreases. The maximum thermal stability exists at Pr = 62.5%; it goes against water quality improvement and should be avoided in practice. A bottom-TCC with Pr > 80% is practical for deep reservoirs such as Sanbanxi Reservoir to decrease the temperature difference between inflow and outflow without the increase of thermal stability. In terms of top-TCC, as Pr increases, the temperature difference between inflow and outflow monotonously increases and thermal stability decreases. The top-TCCs are recommended when a smaller thermal stability is more preferentially considered than outflow temperature, or a cool outflow in the summer is required for downstream coldwater fishes. In addition, the TCC cannot decrease or increase the outflow temperature all of the time throughout the whole year, and it primarily changes the phase and variation range of the outflow temperature. This study quantitatively estimates the potential effect of TCCs on the thermal structure and water environment management and provides a theoretical basis for the application of TCC.

Neural signature of behavioural inhibition in women with bulimia nervosa.

BACKGROUND: Impaired inhibitory control is considered a behavioural phenotype in patients with bulimia nervosa. However, the underlying neural correlates of impaired general and food-specific behavioural inhibition are largely unknown. Therefore, we investigated brain activation during the performance of behavioural inhibition to general and food-related stimuli in adults with bulimia nervosa. METHODS: Women with bulimia and healthy control women underwent event-related fMRI while performing a general and a food-specific no-go task. RESULTS: We included 28 women with bulimia nervosa and 29 healthy control women in our study. On a neuronal level, we observed significant group differences in response to general no-go stimuli in women with bulimia nervosa with high symptom severity; compared with healthy controls, the patients showed reduced activation in the right sensorimotor area (postcentral gyrus, precentral gyrus) and right dorsal striatum (caudate nucleus, putamen). LIMITATIONS: The present results are limited to adult women with bulimia nervosa. Furthermore, it remains unclear whether impaired behavioural inhibition in patients with this disorder are a cause or consequence of chronic illness. CONCLUSION: Our findings suggest that diminished frontostriatal brain activation in patients with bulimia nervosa contribute to the severity of binge eating symptoms. Gaining further insight into the neural mechanisms of behavioural inhibition problems in individuals with this disorder may inform brain-directed treatment approaches and the development of response inhibition training approaches to improve inhibitory control in patients with bulimia nervosa. The present study does not support greater behavioural and neural impairments to food-specific behavioural inhibition in these patients.

Difficulties in emotion regulation across the spectrum of eating disorders.

Theoretical models consider difficulties in emotion regulation (ER) as central trans-diagnostic phenomena across the spectrum of eating disorders (ED). However, there is a lack of studies directly comparing ED subtypes regarding ER problems. Furthermore, patients with anorexia nervosa-restricting type (AN-R) and patients with AN-binge/purge type (AN-BP) have usually been merged into one overall AN group in previous research on ER. In order to overcome these limitations of previous studies, the present study investigated specific ER difficulties in 120 patients with different ED subtypes, including AN-R, AN-BP, bulimia nervosa (BN), and binge-eating disorder (BED). As compared to 60 healthy normal-weight controls (NWC) and 29 healthy over-weight controls (OWC), all ED subtypes reported greater difficulties in ER. ED subtypes did not differ regarding most domains of ER except BED showing less severe ER difficulties in some domains. In addition, AN-BP but not BN reported greater impulse control difficulties than AN-R and BED. The findings underscore the relevance of ER difficulties in ED and support the trans-diagnostic view of ER difficulties being present across the whole spectrum of ED. In addition, the present results suggest that certain domains of ER may be linked more closely to certain ED subtypes than to others.

Neurocircuit function in eating disorders.

OBJECTIVE: Eating disorders are serious psychosomatic disorders with high morbidity and lifetime mortality. Inadequate response to current therapeutic interventions constitutes a challenging clinical problem. A better understanding of the underlying neurobiological mechanisms could improve psychotherapeutic and drug treatment strategies. METHOD: A review highlighting the current state of brain imaging in eating disorders related to the anxiety and pathological fear learning model of anorexia nervosa (AN) and the impulsivity model of binge eating in bulimia nervosa (BN). RESULTS: Available neuroimaging studies in patients with acute AN primarily suggest a hyper-responsive emotional and fear network to food, but not necessarily to eating disorder-unrelated, salient stimuli. Furthermore, patients with AN show decreased activation in the ventral fronto-striatal circuits during the performance of a cognitive flexibility task. Results in patients with BN primarily suggest a hypo-responsive reward system to food stimuli, especially to taste reward. Additionally, patients with BN exhibit impaired brain activation in the inhibitory control network during the performance of general response-inhibition tasks. DISCUSSION: Anxiety and pathological fear learning may lead to conditioned neural stimulus-response patterns to food stimuli and increased cognitive rigidity, which could account for the phobic avoidance of food intake in patients with acute AN. However, further neurobiological studies are required to investigate pathological fear learning in patients with AN. Patients with BN may binge eat to compensate for a hypo-responsive reward system. The impaired brain activation in the inhibitory control network may facilitate the loss of control over food intake in patients with BN.

Inhibitory control and decision making under risk in bulimia nervosa and binge-eating disorder.

OBJECTIVE: To investigate neuropsychological mechanisms of impulsivity in patients with bulimia nervosa (BN) and binge-eating disorder (BED). METHOD: Nineteen BN patients and 31 age- and body-mass-index (BMI)-matched healthy controls (c-BN) as well as 54 overweight and obese BED patients and 43 age- and BMI-matched healthy controls (c-BED) were investigated using an inhibitory control task (stop signal task, SST) and a decision-making under risk task (game of dice task, GDT). RESULTS: Compared to c-BN, BN patients demonstrated significant greater stop signal reaction times in the SST, but no differences for the frequency of risky decisions in the GDT. BED patients did not differ from c-BED in the SST or the GDT. DISCUSSION: BN but not BED patients differed from their respective control groups concerning the "stopping" component of impulsivity. These differences in motor inhibition may contribute to the behavioral distinctions in binge-eating behavior between BN and BED.

Inhibitory Control and Hedonic Response towards Food Interactively Predict Success in a Weight Loss Programme for Adults with Obesity.

OBJECTIVE: Low inhibitory control and strong hedonic response towards food are considered to contribute to overeating and obesity. Based on previous research, the present study aimed at examining the potentially crucial interplay between these two factors in terms of long-term weight loss in people with obesity. METHODS: BMI, inhibitory control towards food, and food liking were assessed in obese adults prior to a weight reduction programme (OPTIFAST® 52). After the weight reduction phase (week 13) and the weight loss maintenance phase (week 52), participants' BMI was re-assessed. RESULTS: Baseline BMI, inhibitory control and food liking alone did not predict weight loss. As hypothesised, however, inhibitory control and food liking interactively predicted weight loss from baseline to week 13 and to week 52 (albeit the latter effect was less robust). Participants with low inhibitory control and marked food liking were less successful in weight reduction. CONCLUSION: These findings underscore the relevance of the interplay between cognitive control and food reward valuation in the maintenance of obesity.

Reward-related decision making in eating and weight disorders: A systematic review and meta-analysis of the evidence from neuropsychological studies.

Eating disorders (EDs) and overweight/obesity (OW/OB) are serious public health concerns that share common neuropsychological features and patterns of disturbed eating. Reward-related decision making as a basic neurocognitive function may trans-diagnostically underlie both pathological overeating and restricted eating. The present meta-analysis synthesizes the evidence from N=82 neuropsychological studies for altered reward-related decision making in all ED subtypes, OW and OB. The overall effect sizes for the differences between currently-ill ED patients and OW/OB people and controls were Hedge's g=-0.49 [CI: -0.63; -0.35], and Hedge's g=-0.39 [CI: -0.53; -0.25], respectively. Decision making was found to be altered to similar degrees in all ED subtypes and OB. Effect sizes, however, diverged for the different measures of decision making. Adolescents appear to be less affected than adults. When foods were used as rewarding stimuli, decision making was found to be intact in OB. The findings support that altered general reward-related decision making is a salient neuropsychological factor across eating and weight disorders in adulthood.

Neural dissociation of food- and money-related reward processing using an abstract incentive delay task.

Food is an innate reward stimulus related to energy homeostasis and survival, whereas money is considered a more general reward stimulus that gains a rewarding value through learning experiences. Although the underlying neural processing for both modalities of reward has been investigated independently from one another, a more detailed investigation of neural similarities and/or differences between food and monetary reward is still missing. Here, we investigated the neural processing of food compared with monetary-related rewards in 27 healthy, normal-weight women using functional magnetic resonance imaging. We developed a task distinguishing between the anticipation and the receipt of either abstract food or monetary reward. Both tasks activated the ventral striatum during the expectation of a reward. Compared with money, greater food-related activations were observed in prefrontal, parietal and central midline structures during the anticipation and lateral orbitofrontal cortex (lOFC) during the receipt of food reward. Furthermore, during the receipt of food reward, brain activation in the secondary taste cortex was positively related to the body mass index. These results indicate that food-dependent activations encompass to a greater extent brain regions involved in self-control and self-reflection during the anticipation and phylogenetically older parts of the lOFC during the receipt of reward.

Inhibitory control in bulimic-type eating disorders: a systematic review and meta-analysis.

The aim of this meta-analysis was to summarise data from neuropsychological studies on inhibitory control to general and disease-salient (i.e., food/eating, body/shape) stimuli in bulimic-type eating disorders (EDs). A systematic literature search was conducted to identify eligible experimental studies. The outcome measures studied included the performance on established inhibitory control tasks in bulimic-type EDs. Effect sizes (Hedges' g) were pooled using random-effects models. For inhibitory control to general stimuli, 24 studies were included with a total of 563 bulimic-type ED patients: 439 had bulimia nervosa (BN), 42 had anorexia nervosa of the binge/purge subtype (AN-b), and 82 had binge eating disorder (BED). With respect to inhibitory control to disease-salient stimuli, 12 studies were included, representing a total of 218 BN patients. A meta-analysis of these studies showed decreased inhibitory control to general stimuli in bulimic-type EDs (g = -0.32). Subgroup analysis revealed impairments with a large effect in the AN-b group (g = -0.91), impairments with a small effect in the BN group (g = -0.26), and a non-significant effect in the BED group (g = -0.16). Greater impairments in inhibitory control were observed in BN patients when confronted with disease-salient stimuli (food/eating: g = -0.67; body/shape: g = -0.61). In conclusion, bulimic-type EDs showed impairments in inhibitory control to general stimuli with a small effect size. There was a significantly larger impairment in inhibitory control to disease salient stimuli observed in BN patients, constituting a medium effect size.

Prevalence of eating disorders in the general population: a systematic review.

BACKGROUND: The estimated prevalence of eating disorders reported in community surveys from different parts of the world varies widely but there has been no systematic attempt to identify the reasons for these differences. OBJECTIVE: Use meta-analysis methods to pool data from community surveys about the prevalence of eating disorders in different locations and to identify the factors that are associated with the reported prevalence of eating disorders. METHODS: Based on pre-defined inclusion and exclusion criteria, studies were identified from the following databases: PubMed/Medline, PsycINFO, ISI web of knowledge, Ovid, Chinese National Knowledge Infrastructure, Chongqing VIP database for Chinese Technical Periodicals, WANFANG DATA, and Chinese Biological Literature Service System. Statistical analysis was conducted using R software. RESULTS: Among the 9315 unduplicated reports reviewed (one-fourth of which were published in Chinese) only 15 - with a pooled sample size of 72,961 individuals - met the inclusion criteria for the analysis. None of the included studies were from China and only one Asian country (South Korea) was included in the analysis. The estimated lifetime prevalence, 12-month prevalence, and 4-week prevalence of any eating disorder was 1.01% (95% confidence interval [CI], 0.54-1.89), 0.37% (CI, 0.22-0.63), and 0.21% (CI, 0.15-0.28), respectively. Estimated lifetime prevalence of anorexia nervosa, bulimia nervosa, and binge eating disorder was 0.21% (CI, 0.11-0.38), 0.81% (CI, 0.59-1.09), and 2.22% (CI, 1.78-2.76), respectively. The estimated female-male ratio for lifetime prevalence of any eating disorder was 4.2. The lifetime prevalence of any eating disorder reported from studies conducted in Western countries was 6.1-fold greater than that reported in a single study from South Korea. Over time there has been a non-significant increase in reported prevalence of any eating disorder and a significant increase in reported prevalence of anorexia nervosa. CONCLUSIONS: Eating disorders are common in the general population, more common in women than men, and more common in Western countries than in Asian countries.The reported prevalence is increasing over time, but this may be due to changes in diagnostic criteria. There are serious limitations in the available epidemiological data, primarily differences in the conditions included among eating disorders and the lack of acceptable epidemiological studies from low- and middle-income countries (including China).