基于市场风险和风险偏好的购电商最优决策研究

结合前景理论刻画了购电商风险规避度,并在此基础上构建了考虑电力用户随机需求的购电商决策模型。通过求解和分析购电商的最优决策,量化分析了决策者风险偏好、市场风险、零售价格、批发价格、购电商成本对最优决策的影响,为风险规避型购电商在市场风险下的最优决策提供了新的指导和参考。     

Increased milk protein content and whey-to-casein ratio in milk served with breakfast cereal reduce postprandial glycemia in healthy adults: An examination of mechanisms of action

This study describes the effects on glycemic response and the underlying mechanisms of action of increasing the protein concentration and decreasing the casein-to-whey ratio in milk when consumed with a high glycemic breakfast cereal. Twelve healthy men and women, aged 18 to 30 yr and with a body mass index of 20 to 24.9 kg/m², consumed (in random order) milk beverages (250 mL) containing either 3.1 or 9.3% protein and casein-to-whey ratios of either 80:20 or 40:60. We measured postprandial appetite, glucose, regulatory hormones, and stomach emptying rate over 200 min, as well as food intake at an ad libitum meal at 120 min. Although pre-meal appetite was suppressed to a greater extent with milk beverages that had high (9.3%) compared with regular (3.1%) protein content, food intake was similar among all 4 treatments. Pre-meal mean blood glucose was lower with beverages that had high rather than regular milk protein content, with the lowest glucose peaks after the high milk protein treatment with the 40:60 casein-to-whey ratio. Pre-meal insulin and C-peptide levels were not affected by milk protein content or casein-to-whey ratio, but pre-meal glucagon-like peptide 1 was higher after the treatment containing high milk protein and the 40:60 casein-to-whey ratio, and pre-meal cholecystokinin was higher after the treatments containing high milk protein content. Plasma paracetamol response was also lower after the treatments containing high compared with regular milk protein content. When consumed with carbohydrate, milk beverages with high protein content and (to a lesser extent) a decreased casein-to-whey ratio lowered postprandial glycemia through insulin-independent mechanisms, primarily associated with delayed stomach emptying.     

Roles of central catecholamine and hypothalamic neuropeptide Y genome in the development of tolerance to phenylpropanolamine-mediated appetite suppression.

Phenylpropanolamine (PPA) is an appetite suppressant. Repeated treatment with PPA can decrease food intake on initial days, but on subsequent days, food intake gradually returns to normal (tolerant effect). In an attempt to investigate the underlying mechanisms of PPA tolerance, the authors examined the roles of catecholamine (CAT) and hypothalamic neuropeptide Y (NPY) genome. Results revealed that pretreatment with either bupropion, a CAT transporter inhibitor, or α-methylparatyrosine, a tyrosine hydroxylase inhibitor, modulated the effect of PPA tolerance. Moreover, results also revealed that the alteration in NPY messenger RNA level coincided with the change of feeding behavior during PPA treatment and that infusions of NPY antisense oligonucleotide into the cerebroventicle abolished the effect of PPA tolerance. These findings suggest that cerebral CAT and hypothalamic NPY genome are involved in the development of tolerance to PPA-induced appetite suppression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persistent hunger for sodium makes brain stimulation not so sweet: Theoretical comment on Morris et al. (2006).

The rewarding value of a stimulus is not fixed but rather is subjective and can vary with motivational state. M. J. Morris, E. S. Na, A. J. Grippo, and A. K. Johnson (2006) (see record 2006-07279-008) report that generating a prolonged sodium appetite decreases the rewarding value of lateral hypothalamic brain stimulation and sucrose intake. The findings support the idea that a specific motivational state can have strong, nonspecific consequences for reward processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mood disturbance fails to resolve across 31 days of cigarette abstinence in women.

Smoking abstinence responses were characterized in 96 female smokers. Participants completed subjective state measures twice per week for 5 weeks and were then randomly assigned to a group required to abstain for 31 days or a control group that continued to smoke. Financial incentives for biochemically verified abstinence resulted in an 81% completion rate. Abstinence-related increases in depression, tension, anger, irritability, and appetite showed little tendency to return to prequit levels and remained significantly elevated above smoke-group levels. In contrast to psychological components of anxiety, physical components decreased to smoke group levels by the 2nd week of abstinence. Trait depression and neuroticism predicted larger increased abstinence-associated negative affect. The Big Five personality dimensions predicted variance not associated with depressive traits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of food on food intake: methodological problems and mechanisms of action.

Emphasis has been placed on the understanding of the regulation of food intake in the hope of aiding the battle against obesity and of helping to ameliorate the anorexia of cancer and eating disorders. Available data suggest that the regulatory system is multifaceted and complex. This review focuses on current research on the regulation of appetite and satiety by carbohydrates, fats, and proteins as well as by artificial sweeteners. Some methodological problems and potential mechanisms of action at the biochemical level are discussed. Evidence suggests that organisms are more successful in defending against calorie dilution than in adjusting to increases in calories. The implications of that defense relative to the use of ersatz nutrients are explored.     

Effect of milk protein intake and casein-to-whey ratio in breakfast meals on postprandial glucose,satiety ratings,and subsequent meal intake

Whey and casein proteins differentially affect postprandial blood glucose and satiety mechanisms, with relevance for type 2 diabetes and obesity. Therefore, the purpose of this work was to investigate the effect of the casein-to-whey protein ratio and total protein concentration of milks consumed with cereal on postprandial blood glucose, appetite ratings, and subsequent food intake in a randomized, controlled, double-blinded study with healthy young adults (n = 32, 23.4 ± 3.1 yr, body mass index = 22.2 ± 2.5 kg/m²). Fasted participants consumed milk (250 mL) with either 80:20 or 40:60 (modified) casein-to-whey protein ratios at commercially normal (3.1%, wt) or high protein (9.3%, wt) concentration, or control (water with whey permeate), each along with 2 servings of oat-based breakfast cereal. Blood glucose concentrations were determined from finger prick blood samples and appetite was assessed using visual analog scales. Participants consumed a measured ad libitum pizza lunch at 120 min and blood glucose determination and appetite assessment continued following the lunch meal (140–200 min) to observe the second meal effect. Pre-lunch (0–120 min) incremental area under the curve (iAUC) and mean change from baseline blood glucose were reduced with consumption of all milk treatments relative to control. However, we found no differences between all treatments on pre-lunch appetite change from baseline and total area under the curve (tAUC) or lunch meal food intake. In terms of protein concentration results, high protein (9.3%, wt) treatments contrasted to normal protein (3.1%, wt) treatments lowered blood glucose change from baseline and iAUC, and post-lunch appetite change from baseline and tAUC. Protein ratio showed a modest effect in that modified (40:60) protein ratio lowered pre-lunch blood glucose change from baseline but not iAUC, and normal (80:20) protein ratio lowered pre-lunch appetite change from baseline but not tAUC. Therefore, high-carbohydrate breakfast meals with increased protein concentration (9.3%, wt) could be a dietary strategy for the attenuation of blood glucose and improved satiety ratings after the second meal.     

The effect of ingesting olestra-based foods on feeding behavior and energy balance in humans

This article reviews currently published works on the effects of olestra on appetite and energy intake (EI) in humans. To date 24 studies have examined the impact of olestra-containing foods on aspects of feeding behavior, which are published in 20 reports. The general response of human subjects to olestra-based decreases in dietary energy density (ED) is either poor caloric compensation or partial (nonmacronutrient specific) increases in EI. Averaging the degree of energy compensation across 22 studies gives a value of 27% (nonweighted mean). In studies where compensation occurred, fat intake but not EI was reduced. These effects appear to occur in both lean and obese, men and women and under a variety of conditions ranging from the laboratory to real life. However, all but two of these studies were short term. One study suggests that in subjects to whom weight loss is desirable these deficits can persist for up to 3 months. Subjects with no wish to lose weight may compensate better over longer periods. In another 3-month study, ingestion of olestra-based foods did not induce energy deficits but limited the significant weight gain seen on a full-fat control. The longer term effects of olestra on body weight requires further investigation. There is evidence that restrained eaters tend to eat slightly more of olestra-based foods if they know that they are reduced in fat and energy. This is probably a general response to low-fat foods rather than to olestra per se. The fact that olestra-based foods have the potential to provide the sensory qualities of real fat suggests that these foods may be particularly effective in habitual high-fat consumers with a sensory preference for dietary fat.     

NPFF Decreases Activity of Human Arcuate NPY Neurons: A Study in Embryonic-Stem-Cell-Derived Model

Restoring the control of food intake is the key to obesity management and prevention. The arcuate nucleus (ARC) of the hypothalamus is extensively being studied as a potential anti-obesity target. Animal studies showed that neuropeptide FF (NPFF) reduces food intake by its action in neuropeptide Y (NPY) neurons of the hypothalamic ARC, but the detailed mode of action observed in human neurons is missing, due to the lack of a human-neuron-based model for pharmacology testing. Here, we validated and utilized a human-neural-stem-cell-based (hNSC) model of ARC to test the effects of NPFF on cellular pathways and neuronal activity. We found that in the human neurons, decreased cAMP levels by NPFF resulted in a reduced rate of cytoplasmic calcium oscillations, indicating an inhibition of ARC NPY neurons. This suggests the therapeutic potential of NPFFR2 in obesity. In addition, we demonstrate the use of human-stem-cell-derived neurons in pharmacological applications and the potential of this model to address functional aspects of human hypothalamic neurons.