994 resultados para weight maintenance


Relevância:

30.00% 30.00%

Publicador:

Resumo:

In a three year study, wintering systems utilizing the grazing of stockpiled perennial hay crop forages or corn crop residues were compared to maintaining cows in a drylot. In the summer of 1992, two cuttings of hay were harvested (June 22 and August 2) from three 10-acre fields containing “Johnstone” endophyte-free tall fescue and “Spreador II” alfalfa, and one cutting of hay was harvested from three 10- acre fields of smooth brome grass. “Arlington” red clover was frost-seeded into the smooth bromegrass fields in 1993 and into tall fescue-alfalfa and smooth bromegrass fields into 1994. Two cuttings of hay were harvested from all fields in subsequent years, and three-year average hay yields for tall fescue-alfalfa and smooth bromegrass-red clover were 4,336 and 3,481 pounds per acre, respectively. Regrowth of the forage following the August hay harvest of each year was accumulated for winter grazing. Following a killing frost in each year, two fields of each stockpiled forage were stocked with cows in midgestation at two acres per cow. Two 10-acre fields of corn crop residues were also stocked at two acres per cow, following the grain harvest. Mean dry matter forage yields at the initiation of grazing were 1,853, 2,173 and 5,797 pounds per acre for fields containing tall fescue-alfalfa, smooth bromegrass-red clover, and cornstalks, respectively. A drylot was stocked with 18 cows in 1992 and 1993 and 10 cows in 1994. All cows were fed hay as necessary to maintain a body condition score of five. During grazing, mean losses of organic matter were -6.4, -7.6, and -10.7 pounds per acre per cow from tall fescue-alfalfa, smooth bromegrass-red clover, and cornstalk fields. Average organic matter loss rates from stockpiled forages due to weathering alone were equal to only 30% of the weathering losses of the corn crop residues. In vitro digestibility of both stockpiled forages and cornstalks decreased at equal rates during grazing each year, with respective annual loss rates of .14, .08, and .06% per day. Cows grazing corn crop residues required an average of 1,321 pounds per cow less hay than cows maintained in the drylot to maintain equivalent body condition during the grazing season. Cows grazing tall fescue-alfalfa or smooth bromegrass-red clover had body weight gains and condition score changes equal to cows maintained in a drylot but required 64% and 62% less harvested hay than cows in the drylot during the grazing season. Over the entire stored forage cows grazing tall fescue-alfalfa and smooth bromegrass-red clover required an average of 2,390 and 2,337 pounds per cow less than those maintained in the drylot. Because less hay was needed to maintain cows grazing stockpiled forages, average annual excesses of 5,629 and 3,868 pounds of hay dry matter per cow remained in the stockpiled tall fescue-alfalfa and smooth bromegrass-red clover systems.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Late long-term potentiation (L-LTP) denotes long-lasting strengthening of synapses between neurons. L-LTP appears essential for the formation of long-term memory, with memories at least partly encoded by patterns of strengthened synapses. How memories are preserved for months or years, despite molecular turnover, is not well understood. Ongoing recurrent neuronal activity, during memory recall or during sleep, has been hypothesized to preferentially potentiate strong synapses, preserving memories. This hypothesis has not been evaluated in the context of a mathematical model representing ongoing activity and biochemical pathways important for L-LTP. In this study, ongoing activity was incorporated into two such models - a reduced model that represents some of the essential biochemical processes, and a more detailed published model. The reduced model represents synaptic tagging and gene induction simply and intuitively, and the detailed model adds activation of essential kinases by Ca(2+). Ongoing activity was modeled as continual brief elevations of Ca(2+). In each model, two stable states of synaptic strength/weight resulted. Positive feedback between synaptic weight and the amplitude of ongoing Ca(2+) transients underlies this bistability. A tetanic or theta-burst stimulus switches a model synapse from a low basal weight to a high weight that is stabilized by ongoing activity. Bistability was robust to parameter variations in both models. Simulations illustrated that prolonged periods of decreased activity reset synaptic strengths to low values, suggesting a plausible forgetting mechanism. However, episodic activity with shorter inactive intervals maintained strong synapses. Both models support experimental predictions. Tests of these predictions are expected to further understanding of how neuronal activity is coupled to maintenance of synaptic strength. Further investigations that examine the dynamics of activity and synaptic maintenance can be expected to help in understanding how memories are preserved for up to a lifetime in animals including humans.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background Protein-energy-malnutrition (PEM) is common in people with end stage kidney disease (ESKD) undergoing maintenance haemodialysis (MHD) and correlates strongly with mortality. To this day, there is no gold standard for detecting PEM in patients on MHD. Aim of Study The aim of this study was to evaluate if Nutritional Risk Screening 2002 (NRS-2002), handgrip strength measurement, mid-upper arm muscle area (MUAMA), triceps skin fold measurement (TSF), serum albumin, normalised protein catabolic rate (nPCR), Kt/V and eKt/V, dry body weight, body mass index (BMI), age and time since start on MHD are relevant for assessing PEM in patients on MHD. Methods The predictive value of the selected parameters on mortality and mortality or weight loss of more than 5% was assessed. Quantitative data analysis of the 12 parameters in the same patients on MHD in autumn 2009 (n = 64) and spring 2011 (n = 40) with paired statistical analysis and multivariate logistic regression analysis was performed. Results Paired data analysis showed significant reduction of dry body weight, BMI and nPCR. Kt/Vtot did not change, eKt/v and hand grip strength measurements were significantly higher in spring 2011. No changes were detected in TSF, serum albumin, NRS-2002 and MUAMA. Serum albumin was shown to be the only predictor of death and of the combined endpoint “death or weight loss of more than 5%”. Conclusion We now screen patients biannually for serum albumin, nPCR, Kt/V, handgrip measurement of the shunt-free arm, dry body weight, age and time since initiation of MHD.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

It is estimated that more than half the U.S. adult population is overweight or obese as classified by a body mass index of 25.0–29.9 or ≥30 kg/m 2, respectively. Since the current treatment approaches for long-term maintenance of weight loss are lacking, the National Institutes of Health state that an effective approach may be to focus on weight gain prevention. There is a limited body of literature describing how adults maintain a stable weight as they age. It is hypothesized that weight stability is the result of a balance between energy consumption and energy expenditure as influenced by diet, lifestyle, behavior, genetics and environment. The purpose of this research was to examine the dietary intake and behaviors, lifestyle habits, and risk factors for weight change that predict weight stability in a cohort of 2101 men and 389 women aged 20 to 8 7 years in the Aerobic Center Longitudinal Study regardless of body weight at baseline. At baseline, participants completed a maximal exercise treadmill test to determine cardiorespiratory fitness, a medical history questionnaire, which included self-reported measures of weight, dietary behaviors, lifestyle habits, and risk factors for weight change, a three-day diet record, and a mail-back version of the medical history questionnaire in 1990 or 1995. All analyses were performed separately for men and women. Results from multivariate regression analyses indicated that the strongest predictor of follow-up weight for men and women was previous weight, accounting for 87.0% and 81.9% of the variance, respectively. Age, length of follow-up and eating habits were also significant predictors of follow-up weight in men, though these variables only explained 3% of the variance. For women, length of follow-up and currently being on a diet were significantly associated with follow-up weight but these variables explained only an additional 2% of the variance. Understanding the factors that influence weight change has tremendous public health importance for developing effective methods to prevent weight gain. Since current weight was the strongest predictor of previous weight, preventing initial weight gain by maintaining a stable weight may be the most effective method to combat the increasing prevalence of overweight and obesity. ^

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Predictions about the ecological consequences of oceanic uptake of CO2 have been preoccupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks the direct effects of CO2 on non-calcareous taxa, particularly those that play critical roles in ecosystem shifts. We used two experiments to investigate whether increased CO2 could exacerbate kelp loss by facilitating non-calcareous algae that, we hypothesized, (i) inhibit the recovery of kelp forests on an urbanized coast, and (ii) form more extensive covers and greater biomass under moderate future CO2 and associated temperature increases. Our experimental removal of turfs from a phase-shifted system (i.e. kelp- to turf-dominated) revealed that the number of kelp recruits increased, thereby indicating that turfs can inhibit kelp recruitment. Future CO2 and temperature interacted synergistically to have a positive effect on the abundance of algal turfs, whereby they had twice the biomass and occupied over four times more available space than under current conditions. We suggest that the current preoccupation with the negative effects of ocean acidification on marine calcifiers overlooks potentially profound effects of increasing CO2 and temperature on non-calcifying organisms.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Introduction. Most studies have described how the weight loss is when different treatments are compared (1-3), while others have also compared the weight loss by sex (4), or have taken into account psychosocial (5) and lifestyle (6, 7) variables. However, no studies have examined the interaction of different variables and the importance of them in the weight loss. Objective. Create a model to discriminate the range of weight loss, determining the importance of each variable. Methods. 89 overweight people (BMI: 25-29.9 kg?m-2), aged from 18 to 50 years, participated in the study. Four types of treatments were randomly assigned: strength training (S), endurance training (E), strength and endurance training (SE), and control group (C). All participants followed a 25% calorie restriction diet. Two multivariate discriminant models including the variables age, sex, height, daily energy expenditure (EE), type of treatment (T), caloric restriction (CR), initial body weight (BW), initial fat mass (FM), initial muscle mass (MM) and initial bone mineral density (BMD) were performed having into account two groups: the first and fourth quartile of the % of weight loss in the first model; the groups above and below the mean of the % of weight loss in the second model. The discriminant models were built using the inclusion method in SPSS allowing us to find a function that could predict the body weight loss range that an overweight person could achieve in a 6 months weight loss intervention.Results. The first discriminant analysis predicted that a combination of the studied variables would discriminate between the two ranges of body weight loss with 81.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.475, p=0.003): Discriminant score=-18.266-(0.060xage)- (1.282xsex[0=female;1=male])+(14.701xheight)+(0.002xEE)- (0.006xT[1=S;2=E;3=SE;4=C])-(0.047xCR)- (0.558xBW)+(0.475xFM)+(0.398xMM)+(3.499xBMD) The second discriminant model obtained would discriminate between the two groups of body weight loss with 74.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.725, p=0.005): Discriminant score=-5.021-(0.052xage)- (0.543xsex[0=female;1=male])+(3.530xheight)+(0.001xEE)- (0.493xT[1=S;2=E;3=SE;4=C])+(0.003xCR)- (0.365xBW)+(0.368xFM)+(0.296xMM)+(4.034xBMD) Conclusion. The first developed model could predict the percentage of weight loss in the following way: if the discriminant score is close to 1.051, the range of weight loss will be from 7.44 to -4.64% and if it is close to - 1.003, the range will be from -11.03 to -25,00% of the initial body weight. With the second model if the discriminant score is close to 0.623 the body weight loss will be above -7.93% and if it is close to -0.595 will be below - 7.93% of the initial body weight. References. 1. Brochu M, et al. Resistance training does not contribute to improving the metabolic profile after a 6-month weight loss program in overweight and obese postmenopausal women. J Clin Endocrinol Metab. 2009 Sep;94(9):3226-33. 2. Del Corral P, et al. Effect of dietary adherence with or without exercise on weight loss: a mechanistic approach to a global problem. J Clin Endocrinol Metab. 2009 May;94(5):1602-7. 3. Larson-Meyer DE, et al. Caloric Restriction with or without Exercise: The Fitness vs. Fatness Debate. Med Sci Sports Exerc. 2010;42(1):152-9. 4. Hagan RD, et al. The effects of aerobic conditioning and/or caloric restriction in overweight men and women. Medicine & Science in Sports & Exercise. 1986;18(1):87-94. 5. Teixeira PJ, et al. Mediators of weight loss and weight loss maintenance in middle-aged women. Obesity (Silver Spring). 2010 Apr;18(4):725-35. 6. Bautista-Castano I, et al. Variables predictive of adherence to diet and physical activity recommendations in the treatment of obesity and overweight, in a group of Spanish subjects. Int J Obes Relat Metab Disord. 2004 May;28(5):697-705.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Transportation Department, Research and Special Programs Administration, Washington, D.C.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Office of Passenger Vehicle Research, Washington, D.C.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

IIT Research Institute, Chicago, Ill.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Office of Passenger Vehicle Research, Washington, D.C.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

National Highway Traffic Safety Administration, Office of Passenger Vehicle Research, Washington, D.C.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Offshore oil and gas pipelines are vulnerable to environment as any leak and burst in pipelines cause oil/gas spill resulting in huge negative Impacts on marine lives. Breakdown maintenance of these pipelines is also cost-intensive and time-consuming resulting in huge tangible and intangible loss to the pipeline operators. Pipelines health monitoring and integrity analysis have been researched a lot for successful pipeline operations and risk-based maintenance model is one of the outcomes of those researches. This study develops a risk-based maintenance model using a combined multiple-criteria decision-making and weight method for offshore oil and gas pipelines in Thailand with the active participation of experienced executives. The model's effectiveness has been demonstrated through real life application on oil and gas pipelines in the Gulf of Thailand. Practical implications. Risk-based inspection and maintenance methodology is particularly important for oil pipelines system, as any failure in the system will not only affect productivity negatively but also has tremendous negative environmental impact. The proposed model helps the pipelines operators to analyze the health of pipelines dynamically, to select specific inspection and maintenance method for specific section in line with its probability and severity of failure.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Resistin, a product of white adipose tissue, is postulated to induce insulin resistance in obesity and regulate adipocyte differentiation. The aim of this study was to examine resistin gene expression in adipose tissue from mice bearing the MAC16 adenocarcinoma, which induces cancer cachexia with marked wasting of adipose tissue and skeletal muscle mass. MAC16-bearing mice lost weight progressively over the period following tumour transplantation, while the weight of control mice remained stable. Leptin mRNA in gonadal fat was 50% lower in MAC16 mice than in controls (p<0.05). Plasma insulin concentrations were also significantly lower in the MAC16 group (p<0.05). However, resistin mRNA level in gonadal fat in MAC16 mice was similar to controls (94% of controls). Thus, despite severe weight loss and significant falls in leptin expression and insulin concentration, resistin gene expression appears unchanged in white adipose tissue of mice with MAC16 tumour. Maintenance of resistin production may help inhibit the formation of new adipocytes in cancer cachexia.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Full editorial: A recent study evaluating the long-term (2 yr) weight reducing efficacy of different types of diets – high or low in carbohydrates (CHOs), protein or fat - confirmed that it is calorie deficit not dietary composition that determines the loss and maintenance of body weight.1 Is there any advantage in following a specific weight loss diet? Short-term use of nutritionally complete commercially available (very) low calorie diets has benefited people with diabetes when  supported by education programmes.2 Initial weight loss has been encouraging with some fad diets eg the Atkins and the South Beach diets, but these diets are difficult to maintain and there are safety issues regarding their short- and long-term use – especially in people with diabetes.3 The types of macronutrients consumed can have a considerable impact on glycaemic control and energy metabolism. Although a low CHO diet additionally enhances initial weight loss by reducing cellular water content, if fat is not proportionally reduced the diet may not benefit the lipid profile for vascular disease risk. High fat and high protein diets – which are simultaneously low in CHOs – increase vulnerability to hypoglycaemia in people taking insulin secretagogues or on insulin therapy, and may promote excess fat metabolism and ketogenesis, particularly in people vulnerable to lack of insulin. Very low protein diets are not recommended as lean body mass tends to be reduced in diabetes. Altering the macronutrient balance has implications for the micronutrient mix: deficiencies are higher if more foods are excluded and conversely specific micronutrient excess can occur with some fad diets. The altered nutrient mix affects intestinal fauna and flora, and gut motility and glycaemic control are influenced by the quantity and type of fibre consumed. Support programmes help individuals achieve long term weight loss and there is mounting evidence that community schemes which educate and promote lifestyle changes may stem the rising tide of obesity and consequent type 2 diabetes.4 Consuming smaller portions of a balanced diet (and adjusting antidiabetic medications accordingly) will create an energy deficit to promote healthy weight loss. Increased movement/exercise will enhance this energy deficit. Knowledge (eg 1g fat has 2.25 times more energy than 1g CHO) allows sensible food choices and compensation for inclusion of small volumes of  ‘naughty but nice’ foods. Ultimately weight control requires self control. References 1. Sacks FM, Bray GA, Carey VJ et al. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. N Engl J Med 2009;360:859–73. 2. Bennett P. Obesity, diabetes and VLCD. Br J Diabetes Vasc Dis 2004;4:328–30. 3. Baldwin EJ. Fad diets in diabetes. Br J Diabetes Vasc DIs 2004;4:333–7. 4. Romon M, Lommoz A, Tafflet M et al. Downward trends in the prevalence of childhood overweight in the setting of 12-year school- and community-based programmes. Public Health Nutr 2008; Dec 28, 1–8 [Epub ahead of print].