Energy expenditure after 2- to 3-hour elective surgical operations

Energy expenditure was measured by indirect calorimetry in 17 adult patients (8 women and 9 men) before surgery, 4 hours immediately after surgery , and 24 hours late after surgery in patients undergoing elective surgery of small-to-medium scope. MATERIAL AND METHODS: The total duration of surgery ranged from 2 to 3 hours. Repeated measures were performed on the same patient, so that each patient was considered to be his/her own control. All patients received a 5% dextrose solution (2000 mL/day) throughout the postoperative period. RESULTS: Men showed a reduction in CO2 production during the immediately after surgery period (257±42 mL/min) compared to before surgery (306±48 mL/min) and late after surgery (301±45 mL/min); this reduction was not observed in women. Energy expenditure was also lower in men during immediately after surgery (6.6 kJ/min). None of the other measurements, including substrate oxidation, showed significant differences. CONCLUSION: Therefore, elective surgery itself cannot be considered an important trauma that would result in increased energy expenditure. According to this study, it is not necessary to prescribe an energy supply exceeding basal expenditure during the immediate after-surgery period. The present results suggest that the energy supply prescribed during the postoperative period after elective surgery of small-to-medium scope should not exceed 5-7 kJ/min, so the patient does not receive a carbohydrate overload from energy supplementation.

Energy expenditure in vocalizations of pigs under stress

Modern swine production faces many challenges nowadays, among which are productivity growth, meat quality improvement, decrease of environmental damage and reduction of cost production. Pigs spend energy to vocalizing, especially when they undergo stress. The waste of energy can increase the cost of production and lead to greater environmental damage. The goal of this study was to estimate the energy spent by pigs under the stress of castration and its effect on the animals' weight gain. Two groups of ten animals each were castrated, being one group with local anesthetic and the other without anesthetic. The piglets' vocalizations were recorded during different stages of the neutering process and then estimated of the amount of energy emitted during each vocalization. Afterwards, this energy was associated with the animals' weight gain. There was no difference in the total energy spent in both groups, since the energy used during the application of anesthetic was similar to the energy spent during the castration of the animals without anesthetic. There was also no correlation between energy spent and the animals' weight gain. It was possible to estimate the amount of energy emitted through vocalization. This energy spent by piglets in pain was greater than in other handling situations (contention, weighting and realease).

Evaluation of energy expenditure in forward and backward movements performed by soccer referees

The aim of this study was to measure the energy expenditure for locomotor activities usually performed by soccer referees during a match (walking, jogging, and running) under laboratory conditions, and to compare forward with backward movements. The sample was composed by 10 male soccer referees, age 29±7.8 years, body mass 77.5±6.2 kg, stature 1.78±0.07 m and professional experience of 7.33±4.92 years. Referees were evaluated on two separate occasions. On the first day, maximal oxygen uptake (VO2max) was determined by a maximal treadmill test, and on the second day, the oxygen consumption was determined in different speeds of forward and backward movements. The mean VO2max was 41.20±3.60 mL·kg-1·min-1 and the mean heart rate achieved in the last stage of the test was 190.5±7.9 bpm. When results of forward and backward movements were compared at 1.62 m/s (walking speed), we found significant differences in VO2, in metabolic equivalents, and in kcal. However, the same parameters in forward and backward movements at jogging velocities (2.46 m/s) were not significantly different, showing that these motor activities have similar intensity. Backward movements at velocities equivalent to walking and jogging are moderate-intensity activities, with energy expenditure less than 9 kcal. Energy expenditure was overestimated by at least 35% when calculated by mathematical equations. In summary, we observed that backward movements are not high-intensity activities as has been commonly reported, and when calculated using equations available in the literature, energy expenditure was overestimated compared to the values obtained by indirect calorimetry.

Solar energy use for water pre-heating in boilers of agro-industries

Energy consumption in the world has been growing every year. The industrial sector represents 27.32% of the world energy demand. Heating systems that use solar energy may contribute with a percentage of the total energy required by industries. This work aimed to study the use of vacuum solar collectors for water pre-heating in boilers. We used four collectors installed according to NBR 15,569; water flow through the tubes was 0.058 L/s, and temperature in the inlet and outlet pipes was measured. Results showed that instantaneous radiation, and inlet fluid and room temperatures are variables that influence the process, reaching water maximum temperature in the solar collector outlet of 97.9 °C, and efficiency of approximately 65% for most experiments. For the financial viability evaluation, the payback study was applied, which resulted in 4; 7 and 5 years, for the respective sources: firewood, LPG (liquefied petroleum gas), and electricity. Regarding the calculation of the annual contribution to the reduction of greenhouse gases, it was, respectively, 2.162 and 356 kg of CO2 per m² of collector tubes, in comparison with firewood and LPG.

Energy demand in citrus production under varied operational efficiency values

Citrus orchards are very important in Brazil, especially in São Paulo State, where occupy an area of 600,000 ha approximately. To identify sustainability degree of citrus production system, an energy analysis allows evaluating efficiency of direct and indirect applied inputs. Thus, this study aimed to evaluate citrus production system under energetic point of view, in which invested energy is paid back with citrus production; being compared within three scenarios for operational field efficiency. As result, by sensitivity analysis was determined that fuel was the main energy demander, followed by pesticides and fertilizers. In operational work capacity analysis, all combinations between efficiency (minimum, typical and maximum) and yield levels became positive in the seventh year, except for the combination minimum efficiency and 10 % less yield, positive in the eighth year. The best combination (maximum efficiency and 10 % more yield) has promoted investment payoff around the sixth and seventh year. By this study, it is possible to determine the total energy demand to produce citrus and indentify the applied inputs that need more attention by the decision-makers. Labor and seedlings can be ommited for further studies with citrus, since they were irrelevant. Management of agricultural machinery may pose an important role on decreasing environmental impact of citrus production.

The influence of fasting/refeeding on the lipoprotein lipase activity of adipose tissue and muscle

Lipoprotein lipase activity in adipose tissue and muscle is modulated by changes in the pattern of food intake. We have measured total lipoprotein lipase activity in adipose tissue and muscle of male Wistar rats (N = 6-10), weighing 200-250 g (~12 weeks), during the refeeding/fasting state following 24 h of fasting. Lipoprotein lipase activity in tissue homogenates was evaluated using a [³H]-triolein-containing substrate, and released [³H]-free fatty acids were extracted and quantified by liquid scintillation. Adipose tissue lipoprotein lipase activity did not completely recover within 2 h of refeeding (60% of refed ad libitum values). Cardiac lipoprotein lipase activity remained increased even 2 h after refeeding (100% of refed ad libitum values), whereas no significant changes were observed in the soleus and diaphragm muscles. Adipose tissue lipoprotein lipase activities were consistently higher than the highest skeletal muscle or heart values. It is therefore likely that adipose tissue, rather than muscle makes the major contribution to triacylglycerol clearance. There was concomitant relatively high lipoprotein lipase activity in both adipose tissue and cardiac muscle during the first few hours of refeeding, therefore cardiac muscle may contribute significantly to triacylglycerol clearance during this period. The results suggest that during fasting, increased lipoprotein lipase activity provides a complementary source of free fatty acids from circulating triacylglycerol, allowing the heart to maintain its continuous, high-energy expenditure.

Time motion analysis of football (soccer) referees during official matches in relation to the type of fluid consumed

The aim of the present study was to determine the effect of volume and composition of fluid replacement on the physical performance of male football referees. Ten referees were evaluated during three official matches. In one match the participants were asked to consume mineral water ad libitum, and in the others they consumed a pre-determined volume of mineral water or a carbohydrate electrolyte solution (6.4% carbohydrate and 22 mM Na+) equivalent to 1% of their baseline body mass (half before the match and half during the interval). Total water loss, sweat rate and match physiological performance were measured. When rehydrated ad libitum (pre-match and at half time) participants lost 1.97 ± 0.18% of their pre-match body mass (2.14 ± 0.19 L). This parameter was significantly reduced when they consumed a pre-determined volume of fluid. Sweat rate was significantly reduced when the referees ingested a pre-determined volume of a carbohydrate electrolyte solution, 0.72 ± 0.12 vs 1.16 ± 0.11 L/h ad libitum. The high percentage (74.1%) of movements at low speed (walking, jogging) observed when they ingested fluid ad libitum was significantly reduced to 71% with mineral water and to 69.9% with carbohydrate solution. An increase in percent movement expended in backward running was observed when they consumed a pre-determined volume of carbohydrate solution, 7.7 ± 0.5 vs 5.5 ± 0.5% ad libitum. The improved hydration status achieved with the carbohydrate electrolyte solution reduced the length of time spent in activities at low-speed movements and increased the time spent in activities demanding high-energy expenditure.

Central obesity and dietary intake in HIV/AIDS patients

OBJECTIVE: To assess the association between dietary intake and central obesity among people living with HIV/AIDS and receiving highly active antiretroviral therapy. METHODS: A cross-sectional study was conducted involving 223 adult individuals in the city of São Paulo city in 2002. The study population was classified according to central obesity, defined as waist-to-hip ratio >0.95 for men and >0.85 for women. The dietary variables studied were energy consumption (in calories and calories/kilo of body weight), macronutrients (in grams and % of energy intake), total fiber (grams) and fruit and vegetables intake (grams). The potential confounders examined were sex, skin color, age, schooling, income, body mass index, physical activity, smoking habits, peripheral CD4+ T lymphocyte count and length of protease inhibitor use. The multiple logistic regression model was performed in order to evaluate the association between central obesity and dietary intake. RESULTS: The prevalence of central obesity was 45.7% and it was associated with greater consumption of lipids: for every increase of 10g of lipid intake the odds of central obesity increased 1.28 times. Carbohydrate consumption showed negative association (OR=0.93) with central obesity after adjustment for control variables. CONCLUSIONS: The results suggest that the amount of carbohydrates and lipids in the diet, regardless of total energy intake, may modify the chance of developing central obesity in the studied population. Nutritional interventions may be beneficial for preventing central obesity among HIV/AIDS patients.

Trans fatty acid intake among the population of the city of São Paulo, Brazil

OBJECTIVE: To analyze the monounsaturated and polyunsaturated trans fatty acid intake among the general population. METHODS: A cross-sectional study was conducted in São Paulo, Southeastern Brazil, in 2003, on a representative sample of 2,298 male and female subjects, including 803 adolescents (12 to 19 years), 713 adults (20 to 59 years) and 782 elderly people (60 years or over). Food intake was measured using 24-hour recall. Mean trans fatty acid intake was described according to gender and age group. RESULTS: The mean trans fatty acid intake was 5.0 g/day (SE = 0.1), accounting for 2.4% (SE = 0.1) of total energy and 6.8% (SE = 0.1) of total lipids. The adolescents had the highest mean intake levels (7.4 g/day; 2.9% of energy) while the adults and the elderly had similar intake (2.2% of energy for both; 6.4% of lipids and 6.5% of lipids, respectively). The mean trans fatty acid intake among adult and elderly women (approximately 2.5% of energy and 7.0% of lipids) was higher than among men in the same age group. The food item with the highest contribution towards trans fatty acids was margarine, accounting for more than 30% of total intake, followed by filled cookies among adolescents and meat among adults and the elderly. CONCLUSIONS: The trans fatty acid intake is above the level recommended by the World Health Organization. Replacement of the trans fatty acids in manufactured food items may be an effective measure for reducing trans fatty acid intake in Brazil.

Assessing usual dietary intake in complex sample design surveys: the National Dietary Survey

The National Cancer Institute (NCI) method allows the distributions of usual intake of nutrients and foods to be estimated. This method can be used in complex surveys. However, the user must perform additional calculations, such as balanced repeated replication (BRR), in order to obtain standard errors and confidence intervals for the percentiles and mean from the distribution of usual intake. The objective is to highlight adaptations of the NCI method using data from the National Dietary Survey. The application of the NCI method was exemplified analyzing the total energy (kcal) and fruit (g) intake, comparing estimations of mean and standard deviation that were based on the complex design of the Brazilian survey with those assuming simple random sample. Although means point estimates were similar, estimates of standard error using the complex design increased by up to 60% compared to simple random sample. Thus, for valid estimates of food and energy intake for the population, all of the sampling characteristics of the surveys should be taken into account because when these characteristics are neglected, statistical analysis may produce underestimated standard errors that would compromise the results and the conclusions of the survey.

High Blood Pressure in Adolescents of Curitiba: Prevalence and Associated Factors

Abstract Background: Arterial hypertension is a major public health problem and has increased considerably in young individuals in past years. Thus, identifying factors associated with this condition is important to guide intervention strategies in this population. Objective: To determine high blood pressure prevalence and its associated factors in adolescents. Methods: A random sample of 1,242 students enrolled in public schools of the city of Curitiba (PR) was selected. Self-administered questionnaires provided family history of hypertension, daily energy expenditure, smoking habit, daily fat intake, and socioeconomic status. Waist circumference was measured following standardized procedures, and blood pressure was measured with appropriate cuffs in 2 consecutive days to confirm high blood pressure. Relative frequency and confidence interval (95%CI) indicated high blood pressure prevalence. Bivariate and multivariate analyses assessed the association of risk factors with high blood pressure. Results: The high blood pressure prevalence was 18.2% (95%CI 15.2-21.6). Individuals whose both parents had hypertension [odds ratio (OR), 2.22; 95%CI 1.28-3.85] and those with high waist circumference (OR, 2.1; 95%CI 1.34-3.28) had higher chances to develop high blood pressure. Conclusion: Positive family history of hypertension and high waist circumference were associated with high blood pressure in adolescents. These factors are important to guide future interventions in this population.

Íon Be H+ em campo elétrico uniforme intenso

The influence of a strong external electric field in chemical bonding is not extensively studied. In this work, the behavior of the potential energy curves of the BeH+ ion in an external electric field is investigated by means of variational calculations using molecular orbitals. For simplicity we consider the case where the external field is parallel to the molecular axis, in the direction of the dipole moment, which raises the polarization of the ion. The effects on dissociation are investigated.

Energetic sustainability of three arabica coffee growing systems used by family farming units in Espírito Santo state

Three growing systems of Arabica coffee were evaluated under the energy perspective, in the state of Espírito Santo in Brazil. The systems are conventional cultivation (CC), cultivation with good agricultural practices (CGP) and organic farming (OF). It was made a comparison of the energy flows within these three systems to show sustainable levels of each one based on production average data of several family-farming units. Therefore, we analyzed crop yield, total energy efficiency reverse (TEER), energy efficiency of ripe coffee (EERC) and non-renewable energy efficiency (NREE). OF system had values for TEER, EERC and NREE of 3.3 4.7 and 7.9 respectively. Yet CC showed values of 1.8, 1.9 and 1.6 for TEER, EERC and NREE respectively. Furthermore, CGP presented values for TEER, EERC and NREE of 0.7, 1.3 and 1.4 respectively. The highest yield was observed in CGP, reaching an amount of 1794 kg ha-1(17,455 MJ); however, this system expends more energy than it converts. Thus, over those points, OF is the most sustainable system.

Role of sympathetic nervous system and neuropeptides in obesity hypertension

Obesity is the most common cause of human essential hypertension in most industrialized countries. Although the precise mechanisms of obesity hypertension are not fully understood, considerable evidence suggests that excess renal sodium reabsorption and a hypertensive shift of pressure natriuresis play a major role. Sympathetic activation appears to mediate at least part of the obesity-induced sodium retention and hypertension since adrenergic blockade or renal denervation markedly attenuates these changes. Recent observations suggest that leptin and its multiple interactions with neuropeptides in the hypothalamus may link excess weight gain with increased sympathetic activity. Leptin is produced mainly in adipocytes and is believed to regulate energy balance by acting on the hypothalamus to reduce food intake and to increase energy expenditure via sympathetic activation. Short-term administration of leptin into the cerebral ventricles increases renal sympathetic activity, and long-term leptin infusion at rates that mimic plasma concentrations found in obesity raises arterial pressure and heart rate via adrenergic activation in non-obese rodents. Transgenic mice overexpressing leptin also develop hypertension. Acute studies suggest that the renal sympathetic effects of leptin may depend on interactions with other neurochemical pathways in the hypothalamus, including the melanocortin-4 receptor (MC4-R). However, the role of this pathway in mediating the long-term effects of leptin on blood pressure is unclear. Also, it is uncertain whether there is resistance to the chronic renal sympathetic and blood pressure effects of leptin in obese subjects. In addition, leptin also has other cardiovascular and renal actions, such as stimulation of nitric oxide formation and improvement of insulin sensitivity, which may tend to reduce blood pressure in some conditions. Although the role of these mechanisms in human obesity has not been elucidated, this remains a fruitful area for further investigation, especially in view of the current "epidemic" of obesity in most industrialized countries.

Oxygen consumption of rats with broad intestinal resection

The study was performed to investigate possible alterations in oxygen consumption in an animal model with broad intestinal resection. Oxygen consumption and the thermal effect of a short meal were measured in rats subjected to short bowel syndrome. Four groups of rats were used. Group I was the control group, group II was sham operated, group III was submitted to 80% jejunum-ileum resection, and group IV was submitted to 80% jejunum-ileum resection with colon interposition. Ninety days after surgery, oxygen consumption was measured over a period of 6 h with the animals fasted overnight. The thermal effect of feeding was determined in another session of oxygen consumption measurement in animals fasted for 12 h. A 12-kcal meal was then introduced into the animal chamber and oxygen consumption was measured for a further 4 h. No differences in fasting oxygen consumption or in the thermal effect of the meal were detected among the groups studied. It is concluded that short bowel syndrome does not affect the overall energy expenditure of rats.