Articles de revues : « Conversione calore »

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Logan, Trevon D. « The Transformation of Hunger Revisited : Reply ». Journal of Economic History 75, n^o 2 (juin 2015) : 526–30. http://dx.doi.org/10.1017/s0022050715000704.

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The higher calorie levels reported in Gazeley, Newell, Bezabith (2015) are a function of a conversion of food quantities to calories that is weighted towards contemporary, calorie-rich foods. Their conversion uses the full distribution of contemporary foods and should not be applied to historical populations. Since Gazeley, Newell, Bezabith assume that industrial workers in the past had access to contemporary foods, the revised calorie levels reflect contemporary diets rather than historical diets.

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Claro, Rafael Moreira, Renata Bertazzi Levy, Daniel Henrique Bandoni et Lenise Mondini. « Per capita versus adult-equivalent estimates of calorie availability in household budget surveys ». Cadernos de Saúde Pública 26, n^o 11 (novembre 2010) : 2188–95. http://dx.doi.org/10.1590/s0102-311x2010001100020.

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This study aims to estimate an adult-equivalent scale for calorie requirements and to determine the differences between adult-equivalent and per capita measurements of calorie availability in the Brazilian population. The study used data from the 2002-2003 Brazilian Household Budget Survey. The calorie requirement for a reference adult individual was based on the mean requirements for adult males and females (2,550kcal/day). The conversion factors were defined as the ratios between the calorie requirements for each age group and gender and that of the reference adult. The adult-equivalent calorie availability levels were higher than the per capita levels, with the largest differences in rural and low-income households. Differences in household calorie availability varied from 22kcal/day (households with adults and an adolescent) to 428kcal/day (households with elderly individuals), thus showing that per capital measurements can underestimate the real calorie availability, since they overlook differences in household composition.

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Wisniak, Jaime. « William John Macquorn Rankine. Thermodynamics, heat conversion, and fluid mechanics ». Educación Química 18, n^o 3 (22 août 2018) : 238. http://dx.doi.org/10.22201/fq.18708404e.2007.3.65955.

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William John Macquorn Rankine (1820-1870) fue un científico, educador e ingeniero muy prolífico y multifuncional, un pionero en el esfuerzo de llevar los recursos de las matemáticas y la física a los problemas prácticos de la ciencia y la ingeniería. Sus contribuciones abarcan un amplio intervalo de actividades: termodinámica, conversión del calor, mecánica de fluidos, construcción de barcos, mecánica de los sólidos y de los suelos, así como temas filosóficos. Él es particularmente famoso por sus contribuciones a la termodinámica, al entendimiento de las máquinas térmicas y al desarrollo de la segunda ley. Entre sus contribuciones en esta área tenemos la escala Rankine de temperaturas y el ciclo de vapor Rankine para la conversión de calor en trabajo. Fue el primero que definió tensión y esfuerzo rigurosamente.

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Obando-Perea, Jairo V., Carlos M. Montaño-Torres, Rita D. Caicedo-Zambrano, María C. Santos-Falcónez, Nixon E. Proaño-Bone et Edinson E. Castro-Uriarte. « Utilización efectiva del enfriador de catalizador ». Polo del Conocimiento 2, n^o 12 (12 mars 2018) : 87. http://dx.doi.org/10.23857/pc.v2i12.413.

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El equipo enfriador de catalizador, es un intercambiador de calor basado en la utilización de agua fresca, que además de enfriar el catalizador regenerado, debido a la combustión del coque que se produce por la conversión de la carga en el reactor, generará vapor de presión media. El crudo reducido generará una mayor cantidad de residuo de carbón en el regenerador, y que por ende al ser combustionado la cantidad de calor liberado será mayor. El objetivo de este trabajo es determinar la cantidad de calor que se liberará según la variación del % en peso de crudo reducido y gasóleo, y calcular la cantidad de agua que se producirá en el Catalyst Cooler al mantener el sistema Reactor-Regenerador a temperatura óptima de operación. Para ello se revisa la literatura, se determinan ecuaciones de transferencia de calor y se detallan los equipos. Se realizan los cálculos sobre la cantidad de coque que se producirá en función de la variación del porcentaje en peso de gasóleo y crudo reducido, además de calcular la cantidad de calor que se generará al combustionar el coque que está adherido al catalizador y que ingresará al regenerador para ser descoquizado y ser recirculado hacia el reactor para un nuevo proceso de conversión. Esto aprovecha energía térmica que antes se desperdiciaba provocando impactos ambientales y pérdidas económicas.

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Boucher, Joshua M., Larisa Ryzhova, Anne Harrington, Jessica Davis-Knowlton, Jacqueline E. Turner, Emily Cooper, David Maridas et al. « Pathological Conversion of Mouse Perivascular Adipose Tissue by Notch Activation ». Arteriosclerosis, Thrombosis, and Vascular Biology 40, n^o 9 (septembre 2020) : 2227–43. http://dx.doi.org/10.1161/atvbaha.120.314731.

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Objective: Perivascular adipose tissue (PVAT) surrounding arteries supports healthy vascular function. During obesity, PVAT loses its vasoprotective effect. We study pathological conversion of PVAT, which involves molecular changes in protein profiles and functional changes in adipocytes. Approach and Results: C57BL6/J mice were fed a 60% high-fat diet for 12 weeks or a cardioprotective 30% calorie-restricted diet for 5 weeks. Proteomic analysis identified PVAT as a molecularly distinct adipose depot, and novel markers for thermogenic adipocytes, such as GRP75 (stress-70 protein, mitochondrial), were identified. High-fat diet increased the similarity of protein signatures in PVAT and brown adipose, suggesting activation of a conserved whitening pathway. The whitening phenotype was characterized by suppression of UCP1 (uncoupling protein 1) and increased lipid deposition, leptin, and inflammation, and specifically in PVAT, elevated Notch signaling. Conversely, PVAT from calorie-restricted mice had decreased Notch signaling and less lipid. Using the Adipoq-Cre strain, we constitutively activated Notch1 signaling in adipocytes, which phenocopied the changes in PVAT caused by a high-fat diet, even on a standard diet. Preadipocytes from mouse PVAT expressed Sca1, CD140a, Notch1, and Notch2, but not CD105, showing differences compared with preadipocytes from other depots. Inhibition of Notch signaling during differentiation of PVAT-derived preadipocytes reduced lipid deposition and adipocyte marker expression. Conclusions: PVAT shares features with other adipose depots, but has a unique protein signature that is regulated by dietary stress. Increased Notch signaling in PVAT is sufficient to initiate the pathological conversion of PVAT by promoting adipogenesis and lipid accumulation and may thus prime the microenvironment for vascular disease.

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Silva, Thiago Rodrigues da, Karina Márcia Ribeiro de Souza Nascimento, Charles Kiefer, Luanna Lopes Paiva Copat, Henrique Barbosa de Freitas, Natália Ramos Batista Chaves, Larissa Albuquerque Rosa Silva, Jeovania Vilhalba Leite et Arnaldo Vitorino Ofiço. « Metabolizable energy levels in diets with a fixed nutrient : calorie ratio for free-range broilers ». Semina : Ciências Agrárias 42, n^o 6supl2 (8 octobre 2021) : 4009–22. http://dx.doi.org/10.5433/1679-0359.2021v42n6supl2p4009.

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The present study proposes to examine the effect of dietary levels of metabolizable energy, under a fixed nutrient:calorie ratio, on the production performance; body fat and protein deposition; and carcass characteristics of free-range broilers from 1 to 84 days of age. Nine hundred unsexed chicks were allocated to six treatments in a completely randomized design with six replicates of 25 birds each. Treatments consisted of diets with varying levels of metabolizable energy (2700, 2800, 2900, 3000, 3100 and 3200 Kcal ME/kg of diet) and a fixed proportion of nutrients relative to the energy level according to the nutritional requirements for each rearing phase. Body weight, weight gain, feed intake, feed conversion, production viability, metabolizable energy intake, protein intake, lysine intake, body fat deposition, body protein deposition and carcass characteristics were evaluated. Data were subjected to analysis of variance and, later, to regression analysis. Increasing levels of metabolizable energy, coupled with a fixed nutrient:calorie ratio, reduced feed intake, increased body weight and weight gain, improved feed conversion and did not affect carcass characteristics. In conclusion, adjusting the nutrient supply according to the dietary energy level improves production performance by improving feed conversion, ensuring adequate nutrient intake and preserving fat and protein deposition in the carcass when the metabolizable energy level is raised up to 3200 Kcal/kg in all rearing stages.

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Ladero, Victor, Ana Ramos, Anne Wiersma, Philippe Goffin, André Schanck, Michiel Kleerebezem, Jeroen Hugenholtz, Eddy J. Smid et Pascal Hols. « High-Level Production of the Low-Calorie Sugar Sorbitol by Lactobacillus plantarum through Metabolic Engineering ». Applied and Environmental Microbiology 73, n^o 6 (19 janvier 2007) : 1864–72. http://dx.doi.org/10.1128/aem.02304-06.

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ABSTRACT Sorbitol is a low-calorie sugar alcohol that is largely used as an ingredient in the food industry, based on its sweetness and its high solubility. Here, we investigated the capacity of Lactobacillus plantarum, a lactic acid bacterium found in many fermented food products and in the gastrointestinal tract of mammals, to produce sorbitol from fructose-6-phosphate by reverting the sorbitol catabolic pathway in a mutant strain deficient for both l- and d-lactate dehydrogenase activities. The two sorbitol-6-phosphate dehydrogenase (Stl6PDH) genes (srlD1 and srlD2) identified in the genome sequence were constitutively expressed at a high level in this mutant strain. Both Stl6PDH enzymes were shown to be active, and high specific activity could be detected in the overexpressing strains. Using resting cells under pH control with glucose as a substrate, both Stl6PDHs were capable of rerouting the glycolytic flux from fructose-6-phosphate toward sorbitol production with a remarkably high efficiency (61 to 65% glucose conversion), which is close to the maximal theoretical value of 67%. Mannitol production was also detected, albeit at a lower level than the control strain (9 to 13% glucose conversion), indicating competition for fructose-6-phosphate rerouting by natively expressed mannitol-1-phosphate dehydrogenase. By analogy, low levels of this enzyme were detected in both the wild-type and the lactate dehydrogenase-deficient strain backgrounds. After optimization, 25% of sugar conversion into sorbitol was achieved with cells grown under pH control. The role of intracellular NADH pools in the determination of the maximal sorbitol production is discussed.

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Atsbha, Tesfalem Aregawi, Taeksang Yoon, Byung-Hoon Yoo et Chul-Jin Lee. « Techno-Economic and Environmental Analysis for Direct Catalytic Conversion of CO2 to Methanol and Liquid/High-Calorie-SNG Fuels ». Catalysts 11, n^o 6 (29 mai 2021) : 687. http://dx.doi.org/10.3390/catal11060687.

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Catalytic hydrogenation of CO2 has great potential to significantly reduce CO2 and contribute to green economy by converting CO2 into a variety of useful products. The goal of this study is to assess and compare the techno-economic and environmental measures of CO2 catalytic conversion to methanol and Fischer–Tropsch-based fuels. More specifically, two separate process models were developed using a process modeler: direct catalytic conversion of CO2 to Fischer–Tropsch-based liquid fuel/high-calorie SNG and direct catalytic conversion of CO2 to methanol. The unit production cost for each process was analyzed and compared to conventional liquid fuel and methanol production processes. CO2 emissions for each process were assessed in terms of global warming potential. The cost and environmental analyses results of each process were used to compare and contrast both routes in terms of economic feasibility and environmental friendliness. The results of both the processes indicated that the total CO2 emissions were significantly reduced compared with their respective conventional processes.

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Pareja Arcila, Juan Carlos, Ilda de Fatima Ferreira Tinoco, Jairo Alexander Osorio Saraz, Keller Sullivan Oliveira Rocha et Márcia Gabrielle Lima Candido. « Zootechnical and physiological performance of broilers in the final stage of growth subjected to different levels of heat stress ». Revista Facultad Nacional de Agronomía 71, n^o 2 (1 mai 2018) : 8469–76. http://dx.doi.org/10.15446/rfna.v71n2.71927.

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El objetivo de este trabajo fue estudiar la influencia de diferentes niveles de estrés térmico del ambiente, incluyendo niveles de confort (25 °C), estrés por calor (28 °C), calor moderado (31 °C), calor alto (34 °C) y calor severo (37 °C), en el desempeño de pollos de engorde en el la última fase de crecimiento (22-42 días), alojados en cámaras climáticas. Se determinaron los parámetros fisiológicos y de comportamiento de los pollos (ganancia de peso (WG), ganancia de peso diaria (DWG), consumo de alimento (FI), índice de conversión alimenticia (FC), mortalidad (MORT), porcentaje de carcasa con relación a la edad y peso corporal (BW), carcasa (CAR), pecho (Bre), muslos (Drum), alas (Win)), de acuerdo a los rangos específicos de temperatura; y se calculó el Índice de Temperatura de Globo Negro y Humedad (ITGH), para el control y evaluación térmica de los tratamientos. En general, las aves mantenidas en temperatura entre 25-28 °C, durante las tres últimas semanas de vida, se comportaron mejor que las expuestas a otras situaciones, e indicando que esta podría ser la temperatura ambiente deseada para las aves en su fase final, en comparación con los otros tratamientos, incluidos los que se mantuvieron a la temperatura recomendada como confort térmico durante todo el período experimental.

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Makertihartha, I. G. B. N., Khoiruddin, Ahmad N. Hakim, P. T. P. Aryanti et I. G. Wenten. « Hydrogenation of Maltose in Catalytic Membrane Reactor for Maltitol Production ». MATEC Web of Conferences 156 (2018) : 08008. http://dx.doi.org/10.1051/matecconf/201815608008.

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Maltitol is one of the low-calorie sweeteners which has a major role in food industries. Due to its characteristics of comparable sweetness level to sucrose, maltitol can be a suitable sugar replacement. In this work, catalytic membrane reactor (CMR) was examined in maltitol production through hydrogenation of maltose. Commercial ceramic membrane impregnated with Kalcat 8030 Nickel was used as the CMR. The reaction was conducted at a batch mode operation, 95 to 110°C of temperature, and 5 to 8 bar of pressure. In the range of working conditions used in this study, up to 47% conversion was achieved. The reaction conversion was significantly affected by temperature and pressure. Results of this preliminary study indicated that CMR can be used for hydrogenation of maltose with good performance under a relatively low operating pressure.

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Li, Jin, Jiajun Chen, Wei Xu, Wenli Zhang, Yeming Chen et Wanmeng Mu. « Efficient Utilization of Fruit Peels for the Bioproduction of D-Allulose and D-Mannitol ». Foods 11, n^o 22 (12 novembre 2022) : 3613. http://dx.doi.org/10.3390/foods11223613.

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Currently, the demand for low-calorie sweeteners has grown dramatically because consumers are more mindful of their health than they used to be. Therefore, bioproduction of low-calorie sweeteners from low-cost raw materials becomes a hot spot. In this study, a two-stage strategy was established to efficiently utilize D-fructose from fruit and vegetable wastes. Firstly, ketose 3-epimerase was used to produce D-allulose from D-fructose of pear peels. Secondly, the residual D-fructose was converted to D-mannitol by the engineered strain co-expression of D-mannitol 2-dehydrogenase and formate dehydrogenase. Approximately 29.4% D-fructose of pear peels was converted to D-allulose. Subsequently, under optimal conditions (35 °C, pH 6.5, 1 mM Mn2+, 2 g/L dry cells), almost all the residual D-fructose was transformed into D-mannitol with a 93.5% conversion rate. Eventually, from 1 kg fresh pear peel, it could produce 10.8 g of D-allulose and 24.6 g of D-mannitol. This bioprocess strategy provides a vital method to biosynthesize high-value functional sugars from low-cost biomass.

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Bera, Debabrata. « KINETIC STUDY COMPARISON OF IMMOBILIZED GLUCOSE ISOMERASE (GENSWEET AND SWEETZYME IT) IN STIRRED TANK REACTOR AND PACKED BED REACTOR ». Journal of Medical pharmaceutical and allied sciences 10, n^o 4 (15 août 2021) : 3115–19. http://dx.doi.org/10.22270/jmpas.v10i4.1387.

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D- Glucose/xylose isomerase catalysis the reversible isomerization of aldoses to ketoses such as D-glucose and D-xylose to D-fructose and D-xylose respectively. High fructose corn syrup (HFCS), a low calorie sugar substitute for cane sugar, utilizes Glucose isomerase enzyme for conversion of glucose to fructose. The conversion of glucose to fructose favours more at high temperature, providing an incentive to utilize thermostable and thermoactive glucose isomerase in High fructose corn syrup (HFCS) production. Present studies emphasize on enzymatic conversion and optimization using Sweetzyme IT extra & Gensweet, commercially available glucose isomerases. The experiments were carried out for enzymatic conversion of glucose to fructose using Gensweet and Sweetzyme in Packed bed reactor (PBR) and Stirred tank reactor (STR). Maximum conversion was seen in Stirred tank reactor (STR) using both of these enzymes, approx 10 % more Fructose conversion comparing it to packed bed reactor (PBR). Also, Stirred tank reactor (STR) reaction conditions such as pH, buffers, cofactor (MgSO4) requirement were optimized to achieve optimum enzyme activity. Analysis of enzymatic conversion samples was done using HPLC-RID (using Zorbax Column). The importance of the divalent cation MgCl2 for optimal enzyme activity was investigated. The enzyme performed best at pH 7.5 and 60°C, using 10mM MgSO4 as a cofactor. Utilizing Gensweet in Stirred tank reactor (STR), the maximum fructose transformation was 44 %. The most activity was detected with Sodium phosphate buffers, and EPPS buffers at pH 7 and 8, accordingly, whereas the least activity was reported with TRIS HCl buffer.

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Xu, Yue, Mya Myintzu Hlaing, Olga Glagovskaia, Mary Ann Augustin et Netsanet Shiferaw Terefe. « Fermentation by Probiotic Lactobacillus gasseri Strains Enhances the Carotenoid and Fibre Contents of Carrot Juice ». Foods 9, n^o 12 (4 décembre 2020) : 1803. http://dx.doi.org/10.3390/foods9121803.

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Carrot juice (straight, 8.5 Brix and concentrated, 15.2 Brix) was fermented by lactic acid bacteria (Lactobacillus gasseri strain DSM 20604 or DSM 20077). Fermentation enhanced the nutritional profile of carrot juice. There was a greater sugar reduction (27%) in fermented straight carrot juices than in the fermented concentrated juices (15%). The sugar reduction was independent of the strain used for fermentation. The two L. gasseri strains synthesised fructosyltransferase enzymes during fermentation of carrot juice samples that enabled conversion of simple sugars primarily into polysaccharides. The level of conversion to polysaccharides was dependent on the L. gasseri strain and juice concentration. Fermentation of carrot juice by L. gasseri enables the production of a nutritionally-enhanced beverage with reduced calorie and prebiotic potential. An additional benefit is the increased carotenoid content observed in straight and concentrated juices fermented by Lactobacillus gasseri DSM 20077 and the concentrated juice fermented by Lactobacillus gasseri DSM 20604.

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Irawati, Evi, Mirzah Mirzah et G. Ciptaan. « PEMAKAIAN ONGGOK FERMENTASI DALAM RANSUM TERHADAP PERFORMA AYAM BURAS PERIODE PERTUMBUHAN ». JURNAL PETERNAKAN 13, n^o 2 (6 janvier 2017) : 48. http://dx.doi.org/10.24014/jupet.v13i2.2418.

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The aims of this research was to study the effect of using fermented onggok in ransum to native chicken performance. The design used was completely randomized design (CRD) with 5 treatment i.e : R1 (10%), R2 (15%), R3 (20%), R4 (25%) and R5 (30%) with 4 replications. The ransum was composed with protein (18%) and calorie (2900 kcal/kg). Result of research shows that using fermented onggok had highly significant effect (P< 0.05) towards the feed consumption, body weight gain and feed conversion of buras. It was concluded that using fermented onggok could increase highly body weight at level 15%.

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Perez Garcia, Gloria Arlette, Martha Cecilia García Santillán, Rachel Alí Sánchez Tapia et Karla Vianey Alcántara López. « Segunda ley de la termodinámica y entropía ». TEPEXI Boletín Científico de la Escuela Superior Tepeji del Río 7, n^o 14 (5 juillet 2020) : 74–76. http://dx.doi.org/10.29057/estr.v7i14.5599.

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La segunda ley de la termodinámica trata de la transferencia de energía entre un sistema y su entorno de tal forma que en un proceso típico se cede calor al sistema y este realiza un trabajo. Se puede decir que en otras palabras, se realiza una conversión en el que la energía llega en forma de calor y sale en forma de trabajo. En esta ley surgen cálculos de sus micro estados de esta ley, mismos que son analizados previamente después de ser calculados y así determinar una conclusión. En el presente trabajo se inscribe dentro de un campo de investigación en el que se contribuya a un mejor entendimiento de la segunda ley de la termodinámica, sus variables, formulas etc. Y también de la entropía con las mismas variables pertenecientes a la misma. Adoptamos la metodología de un mapa conceptual con los puntos más importantes que describen al tema.

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Obasa, S. O. « Growth, survival and nutrient utilization of the brackish water catfish (Chrysicthys walkeri) fry as affected by dietary protein and energy levels ». Nigerian Journal of Animal Production 31, n^o 1 (7 janvier 2021) : 144–50. http://dx.doi.org/10.51791/njap.v31i1.1581.

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The effect of varying dietary protein and calorie levels on the growth, survival and nutrient utilization of 540 brackish water catfish (Chrysicthys walkeri) fry average liveweight of 0.14g was investigated in a 3x3 factorial experiment with 3 calorie levels ( 2800, 3000 and 3200 Kcal ME/Kg diet) and 3 levels of crude protein (36%, 39% and 42%) giving a total of 9 diets, fed to the fish for a period of 56 days. Mean weight gain, specific growth rate, feed conversion ratio, survival and protein productive value were significantly higher (P<0.05) in fish fed diet 6 (3000 Kcal ME/Kg and 42% crude protein) when compared to other diets. Weight gain was highest in diet 6 with a value of 0.64g and lowest (significantly P<0.05) with a value of 71.67% and lowest in diet 1 (2800Kcal ME/Kg and 36% crude protein) with a value of 53.34%, while protein productive value was higher in diet 6 (78.40) and lowest in diet (2800Kcal ME/Kg, 39% crude protein) with a value of value of 64.33%. Thus, C. walkeri for survived and performed best when fed on 42% crude protein and 3000Kcal ME/kg diet.

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Logan, Isabelle E., Gerd Bobe, Cristobal L. Miranda, Stephany Vasquez-Perez, Jaewoo Choi, Malcolm B. Lowry, Thomas J. Sharpton et al. « Germ-Free Swiss Webster Mice on a High-Fat Diet Develop Obesity, Hyperglycemia, and Dyslipidemia ». Microorganisms 8, n^o 4 (5 avril 2020) : 520. http://dx.doi.org/10.3390/microorganisms8040520.

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A calorie-dense diet is a well-established risk factor for obesity and metabolic syndrome (MetS), whereas the role of the intestinal microbiota (IMB) in the development of diet-induced obesity (DIO) is not completely understood. To test the hypothesis that Swiss Webster (Tac:SW) mice can develop characteristics of DIO and MetS in the absence of the IMB, we fed conventional (CV) and germ-free (GF) male Tac:SW mice either a low-fat diet (LFD; 10% fat derived calories) or a high-fat diet (HFD; 60% fat derived calories) for 10 weeks. The HFD increased feed conversion and body weight in GF mice independent of the increase associated with the microbiota in CV mice. In contrast to CV mice, GF mice did not decrease feed intake on the HFD and possessed heavier fat pads. The HFD caused hyperglycemia, hyperinsulinemia, and impaired glucose absorption in GF mice independent of the increase associated with the microbiota in CV mice. A HFD also elevated plasma LDL-cholesterol and increased hepatic triacylglycerol, free fatty acids, and ceramides in all mice, whereas hypertriglyceridemia and increased hepatic medium and long-chain acylcarnitines were only observed in CV mice. Therefore, GF male Tac:SW mice developed several detrimental effects of obesity and MetS from a high-fat, calorie dense diet.

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Hariyati, Rinna, et Isworo Pujotomo. « People’s Electricity Program For Solving Overload Domestic Waste Issue By Converting Trash To Energy Utilizing Bio-Digester Method ». E3S Web of Conferences 73 (2018) : 01003. http://dx.doi.org/10.1051/e3sconf/20187301003.

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Big Rubbish has always been an issue to most major cities in Indonesia. The need to solve, handling and reducing tons of waste has become very urgent. One of the solution is People’s Electricity Program. The Idea is by converting domestic waste to energy in efficient, affordable and eco-friendly ways. The research started in Pondok Kopi RW 10, East Jakarta, converting domestic waste using bio-digester method, and thus experiments succeed turn the trash to compost leachate that can be use as fertilizer as well as forage ingredient. In this article, authors will focus on the detail of An-aerobic Digester known also as bio-digester method which is an alternative technology in The People’s Electricity Program to manage waste, converting it as energy. While researching and developing for People’s Electricity Program, The idea to create briquettes from waste came up. This waste-briquettes is being tested and checked in laboratory where its eventually having calorie level closed to coal’s calorie level. By using the bio-digester method on People’s Electricity Program, the waste-to-energy conversion can be built any where and become a solution to waste management, reducing the amount of junk while giving value provide an energy source for community.

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Olek, Małgorzata, Stanisław Kandefer, Wiesław Kaniowski, Witold Żukowski et Jerzy Baron. « Carbon Shale Combustion in the Fluidized Bed Reactor ». Polish Journal of Chemical Technology 16, n^o 2 (26 juin 2014) : 74–76. http://dx.doi.org/10.2478/pjct-2014-0033.

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Abstract The purpose of this article is to present the possibilities of coal shale combustion in furnaces with bubbling fluidized bed. Coal shale can be autothermally combusted in the fluidized bed, despite the low calorie value and high ash content of fuel. Established concentrations of CO (500 ppm) and VOC (30 mg/m3) have indicated a high conversion degree of combustible material during combustion process. Average concentrations of SO2 and NOx in the flue gas were higher than this received from the combustion of high quality hard coal, 600 ppm and 500 ppm, respectively. Optional reduction of SO2 and NOx emission may require the installation of flue gas desulphurization and de-NOx systems.

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Ali, Mohammad, et Kira M. Villa. « We are how much we Eat : Nutrient-Specific Versus Calorie-Based Adult-Equivalent Scales ». Agriculture and Food Sciences Research 9, n^o 1 (19 avril 2022) : 32–38. http://dx.doi.org/10.20448/aesr.v9i1.3862.

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The accurate conversion of household-level food availability into individual-level nutrient availability depends on which adult-equivalent scale is employed. The purpose of this paper is to come up with a set of adult-equivalent scales based on the specific daily intake requirement for macro- and micronutrients. Using t-tests on household-level data from Nepal, we also attempt to find whether on average there are differences between the individual-level nutrient availability estimates when they are calculated through nutrient-specific versus calorie-based, per capita, or Organization for Economic Cooperation and Development (OECD) adult-equivalent scales. The results suggest that on average there are significant differences between the individual-level nutrient availability estimates depending on which adult-equivalent scale is used. Finally, we find that nutrient-income elasticities calculated through different adult-equivalent scales are statistically different from each other. Thus, the nutrient-specific adult-equivalent scales derived in this paper have the potential to reduce measurement error in future studies.

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Zhang, Chao, Yanzhao Yang, Chiwei Xiao, Zhen You et Xinzhe Song. « Spatio-Temporal Patterns of the Land Carrying Capacity of Tibet Based on Grain Demand and Calorie Requirement ». Land 11, n^o 3 (4 mars 2022) : 380. http://dx.doi.org/10.3390/land11030380.

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Tibet constitutes a major part of the Qinghai–Tibet Plateau (QTP) and is a typical ethnic minority (e.g., Tibetan) and ecologically fragile area in the world. Land resources are one of the most important foundations of food production, and Tibet’s increasingly multi-type food demands are putting new pressure on land resources. However, there is still debate on how many people can be supported with the food production in Tibet. Investigating the land carrying capacity (LCC) in Tibet is very important for maintaining food security and formulating sustainable land management and utilization. Based on an analysis of the unique characteristics of the local farming, pastoral production, and dietary consumption, the spatio-temporal patterns of theLCC in Tibet in 2000–2019 were quantitatively assessed against the grain demands and calorie requirements at three different standards of living (i.e., basic prosperity, comprehensive moderate prosperity, and affluence). The dietary consumption was characterized by the high consumption of grains and meat products, and the low consumption of fruits and vegetables. The LCC in Tibet has continued to increase. The LCC in approximately 60% of the counties increased, with the high-LCC counties concentrated mainly in the Yarlung Zangbo River—Nyangqu River—Lhasa River area, and municipal districts and pastoral counties generally experiencing a low LCC. The load on land resources (LoL) in Tibet exhibited the characteristic of overall balance with local overloads and increasing tensions. More than 50% of the counties experienced population overload, mainly in municipal districts and pastoral counties. Food surplus was mainly found in farming counties, while the food production in pastoral counties was generally unable to meet the calorie demand. Considering the important role of land use in maintaining regional food security and ecological security, the conversion of grassland to cultivated land, the occupation of cultivated land, and the phenomenon of cultivated land was used to non grain should be avoided. Trans-regional transport of food should be strengthened to meet the calorie needs in population overload areas in the future. Our study provides a perspective for evaluating the pressure of land resources. The result can provide a reference for realizing the balance of grain and calorie supply–demand and lay a foundation for formulating sustainable land use policies in the QPT.

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Alves Pereira, Osvaldo, Victor Hugo de Moraes Danelichen, Noel Flávio Costa Ferreira, Eduardo Nogueira dos Santos, Jonathan Willian Zangeski Novais, Henry Helber Calazans Camargo et Benedito Felipe Da Silva Filho. « Tópicos do Método da Razão de Bowen ». UNICIÊNCIAS 25, n^o 1 (14 juin 2021) : 64–68. http://dx.doi.org/10.17921/1415-5141.2021v25n1p64-68.

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Este trabalho teve como objetivo mostrar a dedução física e matemática do método de Bowen na conversão de fluxo de calor latente em unidade de volume de água. A evapotranspiração é o processo natural de fluxo de água para atmosfera. Dentre as técnicas meteorológicas existentes, o método de Bowen consiste na razão entre os fluxos de calor latente (energia destinada para mudança de estado físico da água) e sensível (energia destinada para mudança de temperatura) emitidos por uma superfície durante o processo de evaporação e transpiração das plantas, em função dos gradientes da pressão de vapor e da temperatura observados sobre a superfície. Além disso, o método está fundamentado no princípio de conservação de energia, com fundamentos matemáticos relativamente simples e com modesto aparato instrumental. Palavras-chaves: Fluxo de calor; micrometeorologia; perda de água; atmosfera. Abstract This work aimed to show the physical and mathematical deduction of the Bowen method in the conversion of latent heat flow into a unit of water volume. Evapotranspiration is the natural process of flowing water into the atmosphere. Among the existing meteorological techniques, the Bowen method consists of the ratio between the latent heat flows (energy destined to change the physical state of the water) and sensitive (energy destined to change the temperature) emitted by a surface during the evaporation process and plant transpiration, depending on the vapor pressure and temperature gradients observed on the surface. In addition, the method is based on the principle of energy conservation, with relatively simple mathematical foundations and with modest instrumental apparatus. Keywords: Heat flow; micrometeorology; loss of water; atmosphere.

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Oktaviananda, Cyrilla, et Ilma Fadlilah. « HYDROTHERMAL TREATMENT CAMPURAN BIOMASSA DAN ANALISIS REGRESI MULTIVARIAT ». Jurnal Pengendalian Pencemaran Lingkungan (JPPL) 1, n^o 01 (26 septembre 2019) : 8–16. http://dx.doi.org/10.35970/jppl.v1i01.39.

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Energy needs in Indonesia always increase along with population growth and industrial growth. On the other hand, the abundant availability of biomass waste, especially teak sawdust and corn cobs, encouraged researchers to find the right technique for converting biomass waste to make the waste an alternative energy source. Hydrothermal Treatment is one of the techniques for thermal biomass conversion that can convert biomass into coal-like material called hydrochar. The biomass waste is in a heterogeneous or mixed state.The purpose of this study is to obtain the optimum composition of the biomass mixture to make solid fuels using the hydrothermal treatment method and to do a regression analysis to estimate heating value based on proximate analysis. The biomass waste used in this study was teak sawdust and corn cobs powder. The results from this study are the highest yield of hydrochar in the hydrothermal treatment process of teak sawdust which is equal to 68.1% and the highest calor value in the hydrothermal treatment of biomass with the same composition which is equal to 5402 cal / gram. An equation to predict the value calor hydrochar is HHV = 0.837 (% AC) +0.152 (% VM) +0.389 (% FC) -0.022 (% WC) with an absolute error of 4.11% and a relative error of 0.28 %

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Aachary, Ayyappan Appukuttan, et Siddalingaiya Gurudutt Prapulla. « Value addition to spent osmotic sugar solution (SOS) by enzymatic conversion to fructooligosaccharides (FOS), a low calorie prebiotic ». Innovative Food Science & ; Emerging Technologies 10, n^o 2 (avril 2009) : 284–88. http://dx.doi.org/10.1016/j.ifset.2008.11.013.

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Wierzchowska-McNew, Agata, Mariëlle Engelen, Kristopher Knoop, Gabriella Ten Have et John Thaden. « Changes in Whole-Body Amino Acid Metabolism in Response to 2 Weeks of the Very-Low Calorie Diet Are Not Affected by Gender ». Current Developments in Nutrition 4, Supplement_2 (29 mai 2020) : 1700. http://dx.doi.org/10.1093/cdn/nzaa063_098.

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Abstract Objectives Very Low-Calorie Diet (VLCD) is an approved method to safely achieve substantial short-term weight loss in obese patients. We previously reported that two weeks of the VLCD maintains whole-body protein and amino acid turnover despite a large reduction in lean body mass. Since the observed effects on body weight (BW) and composition differed between men and women, we hypothesized that the changes in amino acid metabolism in a response to the calorie-restricted diet is gender-specific. Methods 34 morbidly obese adults (BMI: 42 ± 0.9 kg/m2, 10 males and 24 females) underwent a VLCD for 2 weeks consisting of 820 kcal/day and 105-grams protein/day. Before the start of the VLCD (baseline), the whole-body production (WBP) rates of multiple amino acids involved in protein metabolism (e.g., glycine (GLY), glutamine (GLN), phenylalanine (PHE), tyrosine (TYR), and arginine (ARG)) were measured after IV pulse administration of their stable isotopes. Weight loss and body composition by dual-energy X-ray absorptiometry were assessed after 2 weeks of the VLCD. Baseline plasma enrichments were measured by LC-MS/MS. Data are presented as mean ± SE. Statistics are performed by Pearson correlation tests. Results The magnitude of the BW loss after 2 weeks of the VLCD differed between males and females (7.0 ± 0.7 kg vs. 4.1 ± 0.2 kg, P < 0.0001, respectively) with a higher reduction in lean body mass observed in men than women (4.3 ± 0.8 kg vs. 2.7 ± 0.4 kg, P < 0.05). Although, females had significantly reduced baseline WBP of ARG (7.3% vs. 2%, P = 0.0027), GLY (22.8% vs. 3.6%, P < 0.001), and PHE (4.8% vs. 3.1%, P = 0.018) in comparison to men, two weeks of the VLCD had a comparable effect on multiple amino acid WBP in both genders. Suppressed contractile myofibrillar protein breakdown rate was observed in both groups (13% vs. baseline, P = 0.02) with no gender difference in net protein breakdown (PHE to TYR conversion rate). Hence, increased catabolism in men cannot be explained by a different response to the 2 weeks of a calorie-restricted diet. Conclusions Despite gender differences in body weight loss and changes in composition in response to a Very Low-Calorie Diet, changes in whole-body amino acid kinetics are not differently affected in men and women. Funding Sources CTRAL Internal Funds.

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Gólcher Barguil, Luis Alejandro. « Análisis de pérdidas del convertidor DC/DC 1-FB-1 ». Revista Ingeniería 30, n^o 1 (26 novembre 2019) : 25–43. http://dx.doi.org/10.15517/ri.v30i1.37299.

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Se plantea el análisis de pérdidas del nuevo Convertidor DC-DC denominado 1-FB-1. El modelo resultante se puede utilizar para predecir con mayor exactitud las razones de conversión reales, que se obtendrían al utilizar elementos prácticos; así como estimar la generación de calor que debe ser removida. Al modelo teórico canónico se le incorporan las pérdidas en el cobre del transformador, las pérdidas de conducción en el transistor, las pérdidas de conducción en el diodo y las pérdidas en la resistencia equivalente serial del capacitor. El análisis establece el marco teórico de las pérdidas de potencia para estudiar su viabilidad en implementaciones con requerimientos de altos de eficiencia, como computadoras portátiles, dispositivos portables y equipos de comunicación.

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Joshi, Niraj Prakash, et Luni Piya. « Food and Nutrient Supply from Organic Agriculture in the Least Developed Countries and North America ». Sustainability 13, n^o 9 (30 avril 2021) : 5068. http://dx.doi.org/10.3390/su13095068.

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Although organic agriculture (OA) is praised unequivocally for its environmental and health benefits, its potential for food security is often questioned because of its perceived lower yield. Least developed countries (LDCs), which have a high prospect of conversion to OA, are underrepresented in the literature related to the yield potential of OA, and its impact on regional food security. This paper aims to assess food and nutrient (calorie, protein, and fat) supply, thereby contributing to food security, from OA using yield ratio (YR) in LDCs and to compare this with North America (NA). Literature is the main source of data to estimate YR. Food supply data available in FAOSTAT for 1963–2013 along with the YR is used to estimate food and nutrient supply from OA in 2013. YR of crops shows a higher yield from OA in LDCs compared to NA. The food supply in LDCs between 1963 and 2013 increased at a higher rate than in NA. However, per capita nutrient supply is growing at a meager rate in LDCs; calorie and protein supply are just above the minimum threshold level and fat supply is still below the threshold level. Cereal is the single most important food item contributing to nutrient supply in LDCs, indicating a lack of dietary diversity. Thus, with relatively higher yields and crop diversity, and localized production and distribution systems, OA will have important contributions in dealing with persistent food insecurity in LDCs. However, a concerted effort is necessary to achieve yield gain and wider acceptance of OA.

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Bin Jardan, Yousef A., Ali Abdussalam, Ayman O. S. El-Kadi et Dion R. Brocks. « Dronedarone : the effect of diet-induced obesity on its metabolism and experimental hyperlipidemia on its metabolism and tissue distribution in the rat ». Canadian Journal of Physiology and Pharmacology 98, n^o 3 (mars 2020) : 177–81. http://dx.doi.org/10.1139/cjpp-2019-0125.

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Dronedarone biodistribution in hyperlipidemia and dronedarone metabolism in hyperlipidemia or obesity were assessed. Male Sprague–Dawley rats were given either normal standard chow with water or various high-fat or high-carbohydrate diets for 14 weeks. There was also a nonobese hyperlipidemic group given poloxamer 407 intraperitoneally. Liver and intestinal microsomes were prepared and the metabolic conversion of dronedarone to desbutyldronedarone was followed. A biodistribution study of dronedarone given orally was conducted in hyperlipidemic and control normolipidemic rats. The metabolism of dronedarone to desbutyldronedarone in control rats was consistent with substrate inhibition. However in the treatment groups, the formation of desbutyldronedarone did not follow substrate inhibition; hyperlipidemia and high-calorie diets created remarkable changes in dronedarone metabolic profiles and reduction in formation velocities. Tissue concentrations of dronedarone were much higher than in plasma. Furthermore, in hyperlipidemia, plasma and lung dronedarone concentrations were significantly higher compared to normolipidemia.

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Kamal, Dianta Mustofa. « COMPARISON OF THE FUEL CALORIFIC VALUE FROM PLASTIC PYROLYSIS WITH COMMERCIAL FUEL ». Jurnal Energi dan Teknologi Manufaktur (JETM) 5, n^o 02 (31 décembre 2022) : 41–44. http://dx.doi.org/10.33795/jetm.v5i02.123.

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Plastic, which is originated from petrolum, is possible to turn it to alternative fuel. Moreover in 2008, the estimated amount of midden in Indonesia reached 38.5 million tons per year with the largest compositions are organic waste (58%), waste plastics (14%), waste paper (9%) and wood waste (4%) (Ministry of Environment, 2008). Meanwhile in Depok City, the amount of waste which goes to Depok City’s landfill waste is 350-400 tonnes / day (Head of Technical Unit Landscape Depok City Sanitation Department, 2012). From the data, above, can be confirmed using plastic waste as an alternative fuel can be superior because plastic waste is the raw material which is cheap, easily processed, and can reduce environmental pollution. The processing of plastic waste into fuel conversion is done using a plastic waste machine with a continuous system, the working principle of heating at high temperature. Tests which are conducted in this study is to test the octane rating by bomb calorie meter, test anylizer gas emissions, and test octane gas chromatography. Plastic waste fuel, which is the outcome from plastic waste conversion machine with continuous system, can be used as fuel for vehicles, it is because the plastic oil calorific value 10 519 cal / g equivalent calorific value premium. This research is expected to address the scarcity of fossil fuels, and increasing public awareness of using alternative fuel, especially plastic waste fuel.

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Durán, Gonzalo José, et Miguel Ángel Condorí. « Modelo físico Y simulación computacional de un colector fotovoltaico-térmico pv/t con circulación de agua ». Extensionismo, Innovación y Transferencia Tecnológica 5 (26 juin 2019) : 401. http://dx.doi.org/10.30972/eitt.503776.

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En este trabajo se desarrolla un modelo téorico para analizar un colector fotovoltaico-térmico (FV/T). El modelo integra los aspectos térmicos y eléctricos, analizando la conversión fotoeléctrica de radiación solar y la cogeneración de calor a baja temperatura mediante la refrigeración con agua en la parte posterior del colector. Se realizó para un día tipo la simulación numérica bajo Simusol de un colector de 40 celdas y 80 Wp, planteando dos escenarios. En el primero se estudió el desempeño del módulo sin circulación de agua, y en el segundo, con circulación de flujo. En la simulación del colector con circulación de agua se encontró que la potencia eléctrica se incrementa en hasta un 15% respecto al caso de estudio sin refrigeración.

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Nguyen, Thi Thanh Hanh, Jae-Young Cho, Ye-Seul Seo, Hye-Jin Woo, Hwa-Kyoung Kim, Ghahyun J. Kim, Deok-Young Jhon et Doman Kim. « Production of a low calorie mandarin juice by enzymatic conversion of constituent sugars to oligosaccharides and prevention of insoluble glucan formation ». Biotechnology Letters 37, n^o 3 (9 novembre 2014) : 711–16. http://dx.doi.org/10.1007/s10529-014-1723-y.

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Shantarin, Vladislav, Yury Zemenkov et Maria Zemenkova. « Ensuring Environmental Safety of Hydrocarbon Pipeline Transport Using Nanotechnology ». Materials Science Forum 871 (septembre 2016) : 192–98. http://dx.doi.org/10.4028/www.scientific.net/msf.871.192.

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The problem of eliminating the consequences of accidents and leaks is particularly relevant in the context of tightened environmental safety requirements. The authors investigated the adsorption capacity of "dry water" for storage of unconventional renewable fuels obtained by the pyrolysis method of oil sludge and oil-contaminated lands management. Existing methods of processing oil wastes have a number of drawbacks: low environmental safety, complexity of technical solutions, high energy costs, lack of final commercial products. The novelty of the research is to upgrade the pyrolysis method of managing oil sludge and oil-contaminated lands without air access in the reactor using electric arc discharge with an increase in consumer properties of the wastes involved in resource management. It was possible to identify the conditions of implementing a particularly effective process mode under which there is a cost-effective conversion of combustibles contained in the wastes into gaseous high-calorie energy sources that can be stored and transported, and used for internal requirements in the fields.Presents the results of studies of innovative materials in the field of leaks utilization

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Mezo-González, Carla Elena, Amran Daher Abdi, Luis Antonio Reyes-Castro, Sandra Olvera Hernández, Clarissa Almeida, Mikaël Croyal, Audrey Aguesse, Elaine Cristina Gavioli, Elena Zambrano et Francisco Bolaños-Jiménez. « Learning Deficits Induced by High-Calorie Feeding in the Rat are Associated With Impaired Brain Kynurenine Pathway Metabolism ». International Journal of Tryptophan Research 15 (janvier 2022) : 117864692211111. http://dx.doi.org/10.1177/11786469221111116.

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In addition to be a primary risk factor for type 2 diabetes and cardiovascular disease, obesity is associated with learning disabilities. Here we examined whether a dysregulation of the kynurenine pathway (KP) of tryptophan (Trp) metabolism might underlie the learning deficits exhibited by obese individuals. The KP is initiated by the enzymatic conversion of Trp into kynurenine (KYN) by indoleamine 2,3-dioxygenase (IDO). KYN is further converted to several signaling molecules including quinolinic acid (QA) which has a negative impact on learning. Wistar rats were fed either standard chow or made obese by exposure to a free choice high-fat high-sugar (fcHFHS) diet. Their learning capacities were evaluated using a combination of the novel object recognition and the novel object location tasks, and the concentrations of Trp and KYN-derived metabolites in several brain regions determined by ultra-performance liquid chromatography-tandem mass spectrometry. Male, but not female, obese rats exhibited reduced learning capacity characterized by impaired encoding along with increased hippocampal concentrations of QA, Xanthurenic acid (XA), Nicotinamide (Nam), and oxidized Nicotinamide Adenine Dinucleotide (NAD+). In contrast, no differences were detected in the serum levels of Trp or KP metabolites. Moreover, obesity enhanced the expression in the hippocampus and frontal cortex of kynurenine monooxygenase (KMO), an enzyme involved in the production of QA from kynurenine. QA stimulates the glutamatergic system and its increased production leads to cognitive impairment. These results suggest that the deleterious effects of obesity on cognition are sex dependent and that altered KP metabolism might contribute to obesity-associated learning disabilities.

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Manjarrez Amaya, Karla Michelle, Ulises Alejandro Villalón López, Miguel Avalos Borja et Juan Manuel Quintana Melgoza. « Hidrocarburos C6−C10 a partir de polietileno residual ». Revista de Ciencias Tecnológicas 3, n^o 1 (21 janvier 2020) : 71–75. http://dx.doi.org/10.37636/recit.v317175.

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En este trabajo de investigación se obtienen hidrocarburos liquidos combustibles (gasolina) con rendimiento del 90% por medio de pirólisis del polietileno de alta densidad (PEAD) a 390 ± 5 °C sobre el catalizador α−PbO. La masa catalítica se varía en 10, 15, 20 y 40% p/p utilizando 10 g de PEAD por cada experimento. El α−PbO se sintetizó a 550 °C en atmósfera de aire durante 1 hora. Los productos líquidos son caracterizados por espectroscopia infrarroja con transformada de Fourier (FT-IR) y cromatografía de gases y espectrometría de masas (GC/MS). La relación óptima experimental de PEAD/α−PbO para la conversión del polietileno residual es 20% α−PbO. Los análisis por FT-IR y GC/MS, permiten corroborar que los líquidos obtenidos corresponden a hidrocarburos con cadenas en un intervalo de 6 a 10 carbonos (C6–C10) y contienen un calor de combustión promedio de 10.9492 kcal/g con potencial aplicación como combustibles alternativos.

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Von Sprecher, Roberto, et María Rosa Di Santo. « Efectos de la globalización y el nuevo orden mundial. Tradición, consumos y desajustes en sociedades mediatizadas ». Revista Latina de Comunicación Social, n^o 54 (10 janvier 1999) : 75–87. http://dx.doi.org/10.4185/rlcs-1999/10.

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Globalización es uno de los vocablos más utilizados actualmente en todas las lenguas, pero no es un fenómeno nuevo como bien lo han demostrado varios autores contemporáneos. John B. Thompson (2) distingue aquella globalización que es sinónimo de términos como internacionalización y transnacionalización cuando el significado es "el fenómeno de la conexión"; de la globalización actual entendida como "la expansión de actividades más allá de los límites de cada estado nacional en particular". La diferencia no es poca. La conexión existía ya en el imperio romano y, por citar casos más cercanos en el tiempo, en el desarrollo y auge del imperialismo del siglo XIX al calor del comercio entre los países centrales y los periféricos. Pero el fenómeno al que llamamos actualmente globalización tiene otras características. Básicamente estamos hablando de globalización según Thompson "solamente cuando el crecimiento de las interconexiones permitan la conversión sistemática y recíproca en algún grado de diferentes regiones y localidades, y solamente cuando el alcance de esas interconexiones sea efectivamente global".

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Tilman, David, et Michael Clark. « Food, Agriculture & ; the Environment : Can We Feed the World & ; Save the Earth ? » Daedalus 144, n^o 4 (septembre 2015) : 8–23. http://dx.doi.org/10.1162/daed_a_00350.

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Secure and nutritious food supplies are the foundation of human health and development, and of stable societies. Yet food production also poses significant threats to the environment through greenhouse gas emissions, pollution from fertilizers and pesticides, and the loss of biodiversity and ecosystem services from the conversion of vast amounts of natural ecosystems into croplands and pastures. Global agricultural production is on a trajectory to double by 2050 because of both increases in the global population and the dietary changes associated with growing incomes. Here we examine the environmental problems that would result from these dietary shifts toward greater meat and calorie consumption and from the increase in agricultural production needed to provide this food. Several solutions, all of which are possible with current knowledge and technology, could substantially reduce agriculture's environmental impacts on greenhouse gas emissions, land clearing, and threats to biodiversity. In particular, the adoption of healthier diets and investment in increasing crop yields in developing nations would greatly reduce the environmental impacts of agriculture, lead to greater global health, and provide a path toward a secure and nutritious food supply for developing nations.

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Mota, Danyelle A., Jefferson C. B. Santos, Diana Faria, Álvaro S. Lima, Laiza C. Krause, Cleide M. F. Soares et Suzana Ferreira-Dias. « Synthesis of Dietetic Structured Lipids from Spent Coffee Grounds Crude Oil Catalyzed by Commercial Immobilized Lipases and Immobilized Rhizopus oryzae Lipase on Biochar and Hybrid Support ». Processes 8, n^o 12 (26 novembre 2020) : 1542. http://dx.doi.org/10.3390/pr8121542.

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The aim of this study was the valorization of coffee industry residues, namely spent coffee grounds (SCG) as a source of oil, and silverskin (CS) as a source of both oil and biomass, under the concept of the circular economy. Therefore, crude oil from SCG was used to produce low-calorie structured lipids (SL) for food and pharmaceutical industries, and CS to produce biochar by pyrolysis for biotechnological uses. SL were obtained by acidolysis with caprylic or capric acid, or interesterification with ethyl caprylate or ethyl caprate, in solvent-free media, catalyzed by immobilized sn-1,3 regioselective lipases. Silverskin biochar (BIO) was directly used as enzyme carrier or to produce hybrid organic-silica (HB) supports for enzyme immobilization. Rhizopus oryzae lipase (ROL) immobilized on Amberlite (AMB), silica (SIL), BIO or HB, and the commercial immobilized Thermomyces lanuginosus (Lipozyme TL IM) and Rhizomucor miehei (Lipozyme RM IM) lipases were tested. Lipozyme RM IM showed better results in SL production than Lipozyme TLIM or ROL on BIO, SIL or HB. About 90% triacylglycerol conversion was attained after 7 h acidolysis or interesterification. Lipozyme RM IM was more stable in interesterification (80% and 65% activity with ethyl caprylate or ethyl caprate) than in acidolysis (first-order decay) after 10 reuses.

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Silva, Mitchell González Soares da, Kiany Sirley Brandão Cavalcante, Ulisses Magalhães Nascimento, Antônio Carlos Sales Vasconcelos, Adeilton Pereira Maciel et Fernando Carvalho Silva. « BENZILAÇÃO DO GLICEROL COM AQUECIMENTO POR MICROONDAS ». Cadernos de Pesquisa 20, n^o 1 (8 mars 2013) : 58. http://dx.doi.org/10.18764/2178-2229.v20.n1.p.58-63.

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A infinidade de aplicações da glicerina incentivou inúmeras pesquisas voltadas ao reaproveitamento do principal coproduto do biodiesel. Destaca-se a produção de aditivos oxigenados para combustíveis, como os éteres, os acetais e os ésteres de glicerina, processos estes que demandam um tempo de reação muito prolongado. Considerando que a aplicação da irradiação de microondas pode influenciar na cinética das reações químicas, o presente trabalho investigou a reação de benzilação do glicerol via catálise homogênea ácida, sob a irradiação de microondas. Foi constatado que o fator variação da potência das micro-ondas apresentou a maior conversão do glicerol dentre todas as variáveis estudadas. Em contrapartida, esta variável também influenciou uma reação indesejável, a autoeterificação do álcool benzílico.Palavras-chave: Benzilação. Glicerol. Álcool benzílico. Microondas.BENZYLATION OF GLYCEROL WITH HEATING BY MICROWAVEAbstract: The multitude of applications of glycerin has encouraged countless researches directed to the reutilization of the main byproduct of biodiesel. Highlighting the production of additives for oxygenated fuels, such as the ethers, the acetal and the esters of glycerin, those processes require a very long reaction time. Whereas the application of irradiation of microwave can influence on the kinetics of chemical reactions, the present work investigated the benzylation reaction of glycerol via catalysis homogeneous acid, in the irradiation of microwave. It was found that the factor power variation of microwave presented the greatest conversion of glycerol among all the variables studied. In contrast, that variable also influenced an undesirable reaction, the self-etherification of benzyl alcohol.Keywords: Benzylation. Glycerol. Benzyl alcohol. Microwave.BENZILACIÓN GLICERINA CON EL CALOR EN MICROONDASResumen: La grande cantidad de aplicaciones de la glicerina ha alentado numerosos estudios dirigidos a la reutilización del principal subproducto de biodiesel. Destacando la producción de aditivos oxigenados de combustibles para motores, tales como éteres, acetales y ésteres de glicerina, estos procedimientos requieren un tiempo de reacción muy largo. Considerando que la aplicación de irradiación de microondas puede influir en la cinética de las reacciones químicas, este estudio investigó la reacción de bencilación de glicerol a través de catálisis homogénea ácida bajo irradiación con microondas. Se encontró que la variación del factor potencia de microondas mostró la mayor conversión de glicerol entre todas las variables evaluadas. En contraste, esta variable también influenció una reacción indeseable, la auto-eterificación de alcohol bencílico.Palabras clave: Bencilación. Glicerol. Alcohol bencílico. Microondas.

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GAVRILÄ‚, Viorica, Mihaela KRUSZLICIKA et Vergina CHIRITESCU. « Food Consumption in Romania - Quantitative and Qualitative Aspects of Food Security ». Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 71, n^o 1 (29 mai 2014) : 57–64. http://dx.doi.org/10.15835/buasvmcn-agr:9606.

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Food security ensurance is determined both by food availability, which depends on agrifood sector and on agricultural trade and by the access to food, which results mainly from the incomes and population purchase power, but also on other factors for example the local market supply, the physical access of persons to food, etc. Starting from these considerents, the paperâ€™s aim is to identify the way in which the internal supply is able to assure the population access to balanced food diet, based on valuable components, respecting the nutritional specialists. Using the methabolical coeficients for macronutrients, it was realised their conversion or equivalence into calories, fact which permitted the assessment of the evolution in time of level and structure of the caloric input. Results obtained show a qualitative modification of the caloric input, by diminution of the level of calories coming from glucides and slight increase of the protein caloric level, mainly the animal origin ones. In the strucuture we can see as a positive aspect, a modification in the caloric share of the glucides, by increase of the input from fruits and vegetables. Structurally at the level of year 2011 the caloric share of nutrient factors is inscribing in the values recommended by nutritionists but there are identified also certain negative tendences which in the future could generate a degradation ofÂ dietâ€™s calorie balance.

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Viktor, Kovalenko. « Determination of economic efficiency of using biogas in the conditions of industrial enterprises ». Theory and practice of metallurgy, n^o 6 (27 novembre 2019) : 12. http://dx.doi.org/10.34185/tpm.6.2019.02.

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To determine the efficiency of biogas use in the existing industrial enterprises of the metallurgical industry of Ukraine and Zaporizhia region, in particular, the basic economic indicators of conversion of standard furnace equipment to biogas mixtures from various derivatives and sources available in the region are calculated. The technical feasibility and economic feasibility of using biogas mixtures as an alternative fuel for energy supply of thermal and heating furnaces of industrial enterprises on the example of a real object are determined. It is shown that to use low-calorie fuel in power equipment, taking into account its quality indicators, it is expedient both separately and in combination with traditional energy sources. It is revealed that the economic indicators of projects for the introduction of biogas technologies at metallurgical enterprises differ depending on many initial conditions, such as: sources of origin and chemical composition of biogas; characteristics of power equipment that is converted to such fuel; the proportion of natural gas substitution in the fuel mixture; etc. Based on the trend of constant growth in the cost of traditional energy resources, the introduction and use of their alternative and renewable counterparts in energy-intensive metallurgical enterprises is relevant and, with the right approach, cost-effective Keywords: energy efficiency, biogas technologies, biogas, natural gas, purification, enrichment, industrial furnaces, economic feasibility

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Ihwan, Khairul, et Roberta Zulfhi Surya. « Analisa Potensi Pengembangan Energi Alternative Berbasis Limbah Kelapa Di Kabupaten Indragiri Hilir ». JUTI UNISI 3, n^o 2 (28 décembre 2019) : 27–31. http://dx.doi.org/10.32520/juti.v3i2.840.

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Indragiri Hilir Regency has the largest coconut plantation in Indonesia with coconut production reaching 390,924.28 tons per year and land area of 295,380.24 hectares (BPS Inhil Regency, 2012). According to Palunkun in Prananta (2004) the composition of coconuts consists of coir 35%, coconut shell 12%, fruit flesh 28% coconut water 25%. So the number of coir and coconut shell that has been burned is 47% of the production of coconut grains. So that coir and shell waste is 643,070,441 tons of waste. Based on research that has been done in the area of extranmigration in Pelangiran sub-district and Belengkong bay sub-district, the potential of coconut waste in the form of coconut fiber is 7,406,000 kg. if the coconut plantations are harvested at the same time. The duration of the harvest for 2.5 to 3 months each time. So that the potential of coconut waste (coconut husk) is 82.288.89 kg / day multiply the calorie value of coconut fiber at 4.004.8 k.cal is 329,546,982.40 K. Kal / kg. if converted into electrical energy with a conversion factor of every tonne of calories is 1.1628x 10-3 MWh (Energy Outlook Statistics, University of Indonesia, 2000) then the potential electrical energy from waste to be produced is 329,546.98 Ton K.Kal X 1 , 1628 x 10 -3 MWh. = 0.383263 Kwh.

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Liu, Zhanzhi, Shuhan Liu, Jingyi Jia, Liuxin Wang, Feng Wang, Xiaoyue Pan, Jing Wu et Sheng Chen. « Optimization of Ultrahigh-Throughput Screening Assay for Protein Engineering of d-Allulose 3-Epimerase ». Biomolecules 12, n^o 11 (24 octobre 2022) : 1547. http://dx.doi.org/10.3390/biom12111547.

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d-Allulose is the corresponding epimer of d-fructose at the C-3 position, which exhibits a similar taste and sweetness to sucrose. As a low-calorie sweetener, d-allulose has broad application prospects in the fields of medicine, food, and so on. Currently, the production method of d-allulose is mainly the enzymatic conversion of d-fructose by d-allulose 3-epimerase (DAEase). However, the limited specific activity and thermal stability of DAEase restrict its industrial application. Herein, an ultrahigh-throughput screening assay based on the transcription factor PsiR was extensively optimized from the aspects of culture medium components, screening plasmid, and expression host, which enhanced the correction between the fluorescent readout and the enzyme activity. Then, the error-prone PCR (epPCR) library of Clostridium cellulolyticum H10 DAEase (CcDAEase) was screened through the above optimized method, and the variant I228V with improved specific activity and thermal stability was obtained. Moreover, after combining two beneficial substitutions, D281G and C289R, which were previously obtained by this optimized assay, the specific activity of the triple-mutation variant I228V/D281G/C289R reached up to 1.42-fold of the wild type (WT), while its half-life (T1/2) at 60 °C was prolonged by 62.97-fold. The results confirmed the feasibility of the optimized screening assay as a powerful tool for the directed evolution of DAEase.

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Mejía Botero, Cristian, Camilo Echeverri Uribe, Andrés A. Amell Arrieta et Marlon Bastidas Barranco. « ANÁLISIS DEL EFECTO DE OPERAR UN REACTOR DE METANACIÓN EN CARGAS DIFERENTES DE LAS DE DISEÑO EN UN PROCESO P2G ». INGENIERÍA : Ciencia, Tecnología e Innovación 9, n^o 1 (6 juin 2022) : 125–34. http://dx.doi.org/10.26495/icti.v9i1.2171.

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En este trabajo se realizó el análisis del efecto operar un reactor de metanación bajo diferentes condiciones de flujo de reactivos. Para ello, se realizaron simulaciones numéricas utilizando el software Aspen Plus con una cinética química del tipo Langmuir-Hinshelwood-Hougen-Watson (LHHW). Se determinaron los parámetros óptimos de diseño (diámetro y masa del catalizador) del reactor basado en el flujo de hidrógeno producido por un electrolizador que consume 4,8 kWe (0,747 mol H2/min), y se evaluó el efecto de trabajar con el mismo reactor, pero con un flujo de H2 proveniente de un proceso de 15 kWe (2,25 mol H2/min), alimentándose con una relación estequiométrica de CO2 (H2:CO2=4:1). Los resultados muestran que el diámetro más adecuado es de 50 mm para la condición de diseño; el uso de diámetros mayores reduce la caída de presión, pero aumenta costos y perjudica la transferencia de calor. Por último, cuando se trabaja el reactor a una condición de flujo superior a la de operación, se genera una disminución de la eficiencia de conversión debido al bajo tiempo de residencia, lo cual repercute en la eficiencia energética del proceso.

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Kazymyrko, V. K., T. S. Silantieva, A. G. Dubkova, L. N. Ivanitska et V. V. Kutovyi. « HOMEOSTASIS OF CHOLESTEROL IN THE BODY, MECHANISMS OF ITS DISORDER, ROLE OF 7α-HYDROXYLASE ». Likarska sprava, n^o 1-2 (25 mai 2021) : 19–31. http://dx.doi.org/10.31640/jvd.1-2.2021(4).

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It has been shown that in humans and animals, CS homeostasis occurs in accordance with the same formula: (СSendog + CSexog) – (CSexcr + BAexcr) = 0. But in herbivores, the positive balance of CS in the body is not occurs; a person creates it by consuming animal products, high-calorie foods and substrates for the synthesis of cholesterol. Like herbivores, it does not need constant intake of cholesterol from the food, the release of which from the body in the form of bile acids is also limited by 7α-hydroxylase activity. This point of view is supported by the fact that a person's daily need for cholesterol can be met by one of its biosynthesis. The paper provides information on the role of liver cholesterol homeostasis and the transformation of cholesterol into bile acids (BA) in the disturbance of homeostasis. Hydroxylation is the only process that irreversibly removes CS from membranes and LP-complexes. For the formation of BA, 60–80 % of the total cholesterol synthesized daily in the body is spent. The rate of the 7α-hydroxylase reaction is affected by the presence of hypercholesterolemia: in experimental animals and in patients with HCS, the rate of the 7α-hydroxylase reaction of the liver is sharply reduced, the rate of conversion of cholesterol to BA and its removal from the body is reduced. A role in atherogenesis of a decrease in the rate of 7α-hydroxylation with aging in humans has been shown. The fact is underlined that the release of cholesterol in the form of bile acids reflects the rate of its synthesis in the body. The formation of BA and the excretion of cholesterol is inhibited by insufficient intake of vitamin C and unsaturated fatty acids into the human body. It is concluded that it is necessary to search for and synthesize substances that enhance the conversion of cholesterol into bile acids and its excretion from the body. The combination of stimulators of bile acid synthesis and blockers of HMG-CoA reductase can significantly increase the effectiveness of treatment of patients with atherosclerosis.

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Havlík, Petr, Hugo Valin, Mario Herrero, Michael Obersteiner, Erwin Schmid, Mariana C. Rufino, Aline Mosnier et al. « Climate change mitigation through livestock system transitions ». Proceedings of the National Academy of Sciences 111, n^o 10 (24 février 2014) : 3709–14. http://dx.doi.org/10.1073/pnas.1308044111.

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Livestock are responsible for 12% of anthropogenic greenhouse gas emissions. Sustainable intensification of livestock production systems might become a key climate mitigation technology. However, livestock production systems vary substantially, making the implementation of climate mitigation policies a formidable challenge. Here, we provide results from an economic model using a detailed and high-resolution representation of livestock production systems. We project that by 2030 autonomous transitions toward more efficient systems would decrease emissions by 736 million metric tons of carbon dioxide equivalent per year (MtCO2e⋅y−1), mainly through avoided emissions from the conversion of 162 Mha of natural land. A moderate mitigation policy targeting emissions from both the agricultural and land-use change sectors with a carbon price of US$10 per tCO2e could lead to an abatement of 3,223 MtCO2e⋅y−1. Livestock system transitions would contribute 21% of the total abatement, intra- and interregional relocation of livestock production another 40%, and all other mechanisms would add 39%. A comparable abatement of 3,068 MtCO2e⋅y−1 could be achieved also with a policy targeting only emissions from land-use change. Stringent climate policies might lead to reductions in food availability of up to 200 kcal per capita per day globally. We find that mitigation policies targeting emissions from land-use change are 5 to 10 times more efficient—measured in “total abatement calorie cost”—than policies targeting emissions from livestock only. Thus, fostering transitions toward more productive livestock production systems in combination with climate policies targeting the land-use change appears to be the most efficient lever to deliver desirable climate and food availability outcomes.

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Jáuregui, Ernesto. « Impact of land-use changes on the climate of the Mexico City Region ». Investigaciones Geográficas, n^o 55 (17 février 2012) : 46. http://dx.doi.org/10.14350/rig.30110.

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Es conocido el hecho de que los cambios de uso del suelo tienen un impacto directo en la capa planetaria alterando el régimen de temperatura y precipitación a escala local. Ubicada en el altiplano central del país, la cuenca de México (7 500 km2) ha sufrido una intensa conversión de la vegetación natural por áreas agrícolas o urbanas mediante la deforestación. Para dar una idea de dichos cambios, la capital del país ocupaba en 1960 un 6% del área de la cuenca mientras que al finalizar el siglo XX la extensión de la urbe era ya del 20% de la superficie total. Este incremento fenomenal del área urbanizada ha impactado el régimen termal en grandes porciones de la cuenca. Utilizando datos de temperatura y precipitación para un periodo aproximado de 25 años, en este trabajo se intenta documentar los cambios climáticos interdecadales inducidos por las modificaciones del uso del suelo. Los resultados muestran que en extensas áreas de la cuenca las temperaturas máximas anuales mantienen una tendencia positiva (de 0.07° C/año). Este contraste se hace más marcado cuando se utiliza la temperatura mínima donde en sitios suburbanos el incremento promedio por áreas es 0.15° C/año mientras que en áreas rurales el cambio correspondiente es casi la mitad (0.08° C/año) para el periodo 1961-85. Este resultado ilustra el mayor impacto que ha tenido el fenómeno de la isla de calor en el cambio climático observado en comparación con el correspondiente al ámbito rural.

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Pérez Carmona, F. E., M. A. Martínez-Pichardo et O. A. Soto-Gutiérrez. « Efecto del bicarbonato de sodio y vitamina C como antiestresores de calor en el rendimiento productivo en pollos Broiler de la línea Cobb 500, León-Nicaragua ». Rev. iberoam. bioecon. cambio clim. 8, n^o 15 (9 juin 2022) : 1863–75. http://dx.doi.org/10.5377/ribcc.v8i15.14314.

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El objetivo del estudio fue evaluar el efecto del bicarbonato de sodio y vitamina C en el comportamiento productivo en pollos Broiler de la línea Cobb-500. Se utilizó un diseño completamente al azar (DCA) y se empleó la prueba de Duncan por medio del programa estadístico InfoStat Versión 2008. El estudio duró 6 semanas, se utilizaron 120 pollos de un día de edad con 40 pollos por tratamiento. Se evaluaron 3 tratamientos: control (sin adición), vitamina C en dosis de 5 mg/lt y bicarbonato de sodio en dosis de 48 mg/lt en el agua. No se encontró diferencia significativa entre los tratamientos. El bicarbonato de sodio presento mejores resultados. El mayor consumo de alimento total lo obtuvo el grupo bicarbonato con 168902 g, seguido el control con 164507 g y vitamina C con 163885 g. El mejor peso promedio total lo obtuvo el grupo bicarbonato con 201 g, seguido el control con 2638 g y vitamina C con 2574 g. La ganancia de peso promedio fue mejor para el grupo bicarbonato con 2651 g, seguido el control con 2590 g y vitamina C con 2524 g. La mejor conversión alimenticia lo obtuvo el grupo bicarbonato y control con 1.63 respectivamente, seguido vitamina C con 1.71. Se reporta una mortalidad de 2.5% para el grupo bicarbonato y control respectivamente y 5% para vitamina C. El registro de temperatura y humedad relativa promedio en la galera fue de 28°C y 66% respectivamente.

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Olivieri, Oliviero, Domenico Girelli, Margherita Azzini, Anna Maria Stanzial, Carla Russo, Massimiliano Ferroni et Roberto Corrocher. « Low Selenium Status in the Elderly Influences Thyroid Hormones ». Clinical Science 89, n^o 6 (1 décembre 1995) : 637–42. http://dx.doi.org/10.1042/cs0890637.

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1. Iodothyronine 5′-deiodinase, which is mainly responsible for peripheral triiodothyronine (T3) production, has recently been demonstrated to be a selenium-containing enzyme. In the elderly, reduced peripheral conversion of thyroxine (T4) to T3 and overt hypothyroidism are frequently observed. 2. We measured serum selenium and erythrocyte glutathione peroxidase (as indices of selenium status), thyroid hormones and thyroid-stimulating hormone in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to exclude abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid conditions of undernutrition or malnutrition, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. 3. In order to properly assess the influence of selenium status on iodothyronine 5′-deiodinase type I activity, a double-blind placebo-controlled trial was also carried out on 36 elderly subjects, resident at a privately owned nursing home. 4. In the free-living population, a progressive reduction of the T3/T4 ratio (due to increased T4 levels) and of selenium and erythrocyte glutathione peroxidase activity was observed with advancing age. A highly significant linear correlation between T4, T3/T4 and selenium was observed in the population as a whole (for T4, R = −0.312, P < 0.002; for T3/T4 ratio, R = 0.32, P < 0.01) and in older subjects (for T4, R = −0.40, P < 0.05; for T3/T4 ratio, R = 0.54, P < 0.002). 5. The main result of the double-blind placebo-controlled trial was a significant improvement of selenium indices and a decrease in the T4 level in selenium-treated subjects; serum selenium, erythrocyte glutathione peroxidase activity and thyroid hormones did not change in placebo-treated subjects. 6. We concluded that selenium status influences thyroid hormones in the elderly, mainly modulating T4 levels.

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Fortes, António Gonçalves, et Baltazar Raimundo. « Bioenergia em Moçambique : tecnologias de produção, uso e aspetos sustentáveis ». Desenvolvimento Socioeconômico em Debate 6, n^o 1 (30 avril 2020) : 60. http://dx.doi.org/10.18616/rdsd.v6i1.5777.

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Face aos problemas socioambientais e econômicos resultantes do uso dos combustíveis fósseis, Moçambique vem implementado diversos projetos de inclusão das energias renováveis (ER) na matriz energética nacional. Uma alternativa promissora é o uso da bioenergia, com vista a explorar seu potencial para produção de energia de forma sustentável. Nessa perspectiva, este artigo objetiva realizar a caracterização do setor de biomassa e bioenergia em Moçambique, através das tecnologias usadas no processamento, o contexto legal e os aspetos sustentáveis na produção e utilização desta fonte. Os resultados mostram que a biomassa (sólida, liquida e gasosa) pode ser utilizada diretamente para geração de calor e/ou eletricidade. A biomassa lenhosa é a mais usada pela população moçambicana para fins domésticos, e casualmente, para fins comercial e industrial. Concluir que, para o atual cenário nacional, a inclusão da biomassa derivada de rejeitos urbanos e industriais pode resolver, em simultâneo, o problema energético e de gestão de resíduos. É sustentável a relação entre a produção de alimento – geração de energia – preservação do meio ambiente. E o uso de tecnologias eficientes na geração dos biocombustíveis reduz os impactos ambientais e a dependência dos combustíveis fósseis, para além de promover os serviços de maior qualidade, contribuir para o aumento da eficiência de conversão e na sustentabilidade energética, especialmente na área rural.Palavras chaves: bioenergia; fonte alternativa; tecnologias de produção; sustentabilidade.Bioenergy in Mozambique: production technologies, use and sustainable aspectsABSTRACTIn view of the socio-environmental and economic problems resulting from the use of fossil fuels, Mozambique has implemented several projects to include renewable energies (RE) in the national energy matrix. A promising alternative is the use of bioenergy, with a view to exploring its potential for sustainable energy production. In this perspective, this article aims to characterize the bioenergy sector in Mozambique, through the technologies used in the conversion, the legal context and the sustainable aspects in the production and use of this source. The results show that biomass (solid, liquid and gaseous) can be used directly to generate heat and/or electricity. Woody biomass is the most used by the Mozambican population for domestic purposes, and casually, for commercial and industrial purposes. To conclude that, for the current national scenario, the inclusion of biomass derived from urban and industrial waste can simultaneously solve the energy and waste management problem. The relationship between food production - energy generation - preservation of the environment is sustainable. And the use of efficient technologies in generation of biofuels reduces environmental impacts and dependence on fossil fuels, in addition to promoting higher quality services, contributing to increasing conversion efficiency and energy sustainability, especially in rural areas.Keywords: bioenergy; alternative source; production technologies; sustainability.

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Ambríz Díaz, Víctor Manuel, Carlos Rubio Maya, J. Jesús Pacheco Ibarra et Edgar Pastor Martínez. « Análisis exergético convencional aplicado a una planta de poligeneración operando en cascada geotérmica ». Ingeniería Investigación y Tecnología 20, n^o 3 (1 juillet 2019) : 1–10. http://dx.doi.org/10.22201/fi.25940732e.2019.20n3.035.

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En este trabajo se presenta un análisis exergético convencional aplicado a una planta de poligeneración que utiliza energía geotérmica para producir electricidad, enfriamiento y calor útil para deshidratación. La planta de poligeneración opera mediante energía geotérmica de media entalpia y está conformada por varias tecnologías de conversión de energía que operan en tres niveles en una cascada geotérmica. El primer nivel térmico lo constituye un Ciclo de Rankine Orgánico (ORC) con el que se produce electricidad. El segundo nivel térmico está compuesto por una máquina de refrigeración por absorción mediante la que se produce un efecto de enfriamiento para conservación de productos a baja temperatura dentro de una cámara fría, así como para mantener más estable la temperatura de condensación del ORC. La energía térmica del último nivel de la cascada geotérmica se destina para operar un deshidratador. Para determinar las prestaciones energéticas del sistema, la planta de poligeneración se sometió a un análisis de exergía convencional para determinar la exergía destruida en cada componente y de toda la planta. La planta se modeló trabajando bajo parámetros operativos reales, inevitables e ideales para obtener el comportamiento termodinámico bajo diferentes criterios de eficiencia. Los resultados muestran que la planta de poligeneración operando bajo condiciones reales presenta la mayor destrucción de exergía (124.1 kW), la más baja eficiencia exergética (26.9%), y la menor producción de productos energéticos. Los resultados también muestran que teniendo en cuenta las condiciones inevitables, el rendimiento de la planta aumenta hasta alcanzar una eficiencia exergética de 29.6%. Por último, la planta de poligeneración tiene un límite de eficiencia exergética de 77.5%, que corresponde a la operación en condiciones ideales. Los valores obtenidos en este estudio son importantes, ya que marcan una pauta para proponer mejoras de manera individual en componentes y en la planta en general.

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