Orientador: Enes Furlani Junior / Resumo: O N é um dos elementos mais dinâmicos no solo, conforme sua transformação no meio. A lixiviação de nitrato e do amônio no solo é considerada a principal perda do N disponível às plantas, quanto maior for à aplicação deste elemento no solo, maior será o potencial de poluição do solo e da água. Objetivou-se, neste trabalho, avaliar a lixiviação de amônio e nitrato em um Latossolo Vermelho em diferentes profundidas do solo, em função de doses e fontes de N distintas, em sistemas irrigado e não irrigado nas condições de campo. O experimento foi conduzido no ano agrícola 2014/15, na área experimental da fazenda de ensino, pesquisa e extensão, localizada no município de Selvíria-MS. Utilizou-se o delineamento em blocos casualizados, com 20 tratamentos dispostos em fatorial 5x2x2, com 4 repetições. Aplicou-se 5 doses de nitrogênio (0 (testemunha); 25; 50; 100 e 150 kg de N ha-1), as fontes de N utilizadas foram: nitrato de amônio e a ureia, aplicados em uma única adubação de cobertura via solo aos 45 após a emergência. As amostras de solo colhidas foram analisadas em laboratório, para a determinação da concentração da lixiviação do NO3- e do NH4+ no solo. Avaliou – se os parâmetros de crescimento, estado nutricional e da produtividade do algodoeiro durante seu ciclo. Os resultados permitiram concluir que o sistema irrigado foi o que propiciou maior lixiviação dos teores de nitrato e amônio nas profundidades de 0 a 0,8 m do solo e o sistema não irrigado foi o que apresentou maior con... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The N is one of the most dynamic elements in the soil, according to its transformation in the environment. The leaching of nitrate and ammonium in the soil is considered the main loss of the N available to the plants, the greater the application of this element in the soil, the greater the pollution potential of soil and water. The objective of this work was to evaluate the leaching of ammonium and nitrate in a Red Latosol in different depths of the soil, as a function of different N sources and sources, in irrigated and non-irrigated systems under field conditions. The experiment was conducted in the agricultural year 2014/15, in the experimental area of the teaching, research and extension farm, located in the municipality of Selvíria, Brasil state of mato grosso do sul. A randomized complete block design was used, with 20 treatments arranged in 5x2x2 factorial, with 4 replications. Five nitrogen doses (0 (control), 25, 50, 100 and 150 kg of N ha-1) were applied, the N sources used were: ammonium nitrate and urea, applied in a single cover fertilization only at 45 after the emergency. The soil samples collected were analyzed in the laboratory for the determination of the leaching concentration of NO3- and NH4+ in the soil. The parameters of growth, nutritional status and yield of cotton during its cycle were evaluated. The results allowed to conclude that the irrigated system provided the highest leaching of the nitrate and ammonium contents in the 0 to 0,8 m depths of the ... (Complete abstract click electronic access below) / Mestre

This diploma thesis is focused on calculation of both structure and electronic properties of the graphene after the adsorption of atomic and molecular oxygen and urea using the Density Functional Theory (DFT). The influence of van der Waals interactions on the structure and adsorption energy is studied, as well as influence of the thermal corrections, the charge density spatial distribution and the electronic doping of graphene after the adsorption of the adsorbant on the graphene.

Tesis para optar al Grado de Magister en Ciencias Agropecuarias, Mención en Producción Frutícola / El palto es una especie susceptible a la carencia de Fe, debido a que los suelos con pH neutro-alcalino y alta concentración de carbonatos reducen la capacidad de absorción de este elemento por la planta, provocando el síntoma conocido como clorosis férrica. Los métodos actuales para corregir el problema, como uso de quelatos y ácidos, son onerosos y contaminantes. En tal contexto se propuso como alternativa el uso de fertilizantes nitrogenados amoniacales, los cuales tienen un efecto acidificante en el pH del suelo y la rizósfera. Para este propósito se evaluó la urea y el sulfato de amonio, aplicados en forma simple y acompañados con un inhibidor de nitrificación (DMPP), así como dos tratamientos control, un absoluto (nitrato de calcio) y un positivo (nitrato de calcio + quelato Fe-EDDHA). El ensayo se ubicó en la localidad de Hijuelas y se utilizaron paltos “Hass” de 3 años de edad. Los resultados indicaron que las aplicaciones de sulfato de amonio con y sin DMPP redujeron la concentración de carbonatos totales y caliza activa, así también redujeron el pH del suelo. Por otra parte, los paltos tratados con sulfato de amonio + DMPP, urea, y nitrato de calcio + Fe-EDDHA alcanzaron un 25% de incremento en la concentración de clorofila en hojas en comparación con el resto de los tratamientos, mientras que en crecimiento de brote, actividad fotosintética y conductancia estomática foliar no mostraron diferencias significativas entre los tratamientos. / Avocado trees are highly susceptible to Fe deficiency, in soils with neutral-alkaline pH and high concentration of carbonate the absorption capacity of this element by the plant is reduced, causing the symptom known as iron chlorosis. Currently, methods to control this problem are based on the use of Fe chelates and inorganic acids applications to soil, being these expensive and polluting techniques. In this context it was proposed, as an alternative, the use of ammonium based nitrogen fertilizers, which can decrease the soil and rhizosphere pH. Urea and ammonium sulphate were applied simply and accompanied with an nitrification inhibitor (DMPP), plus two control treatments, an absolute (calcium nitrate) and a positive (calcium nitrate + Fe-EDDHA chelate). The experiment was located in Hijuelas and 3 years old avocados cv. “Hass” trees were used. Results indicated that applications of ammonium sulfate with and without DMPP decreased the concentration of total carbonates and active lime, and also soil pH was reduced. Moreover, avocados treated with DMPP + ammonium sulphate, urea and calcium nitrate + Fe-EDDHA reached a 25% increase in the concentration of chlorophyll in leaves compared with other treatments, while shoot growth, photosynthetic activity and leaf stomatal conductance showed no significant differences.

The efficiency of utilization of dietary nitrogen can be monitored using milk urea nitrogen (MUN). Overfeeding or underfeeding of protein can be identified through the observation of deviations from target MUN concentrations. This will assist in lowering feed costs of dairy farms, and improving nutrition management of herds. Higher efficiency of utilization of dietary nitrogen might result in a reduction in environmental pollution. Non-genetic factors affecting variation in MUN were herd-test-day (HTD), lactation stage and year of calving. The contribution of HTD was the highest, ranging from 58.56% to 63.18% in parity 1 to 3. Lactation stage had the second largest contribution to the MUN variation. Differences in least squares means for MUN in various years of calving were observed. The heritability estimate for MUN was 0.09±0.01 in the first parity, and remained constant at 0.11±0.01 in the second and third parity. Heritability estimates for milk, fat and protein yield ranged from 0.40±0.01 to 0.43±0.01, 0.21±0.01 to 0.26±0.01, and 0.32±0.01 to 0.38±0.01, respectively. These estimates were within acceptable ranges for South African Holstein cattle. Genetic correlations between MUN and milk production traits were low and positive, ranging from 0.01±0.003 to 0.10±0.004 across parities. Phenotypic correlations ranged from 0.02±0.11 to 0.16±0.07, being generally higher than the genetic correlations. The positive associations between MUN and milk production traits are undesirable as the dairy cows would be less efficient in utilizing dietary protein and may result in increased environmental pollution. The genetic trend for MUN was 0.44, 0.007 and 0.049 mg/dl in the first, second and third parity, respectively. Results of the current study indicate that MUN has potential as a management tool in South African Holstein dairy herds. It might be a good indicator of the efficiency of dietary protein utilization of dairy herds, and has practical advantage as it is currently collected by the national dairy herd recording and improvement scheme. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Animal and Wildlife Sciences / unrestricted

Tesis para optar al Título Profesional de Ingeniero Agrónomo y al Grado de Magister en Ciencias Agropecuarias, Mención Producción Animal / Se realizó un ensayo en la Estación Experimental Oromo dependiente del Departamento de Producción Animal de la Facultad de Ciencias Agronómicas, Universidad de Chile. El objetivo de esta investigación fue evaluar el efecto de la suplementación energética sobre la respuesta metabólica y productiva, en vacas consumiendo praderas de un alto contenido proteico. El estudio fue realizado durante los meses de Noviembre y Diciembre del año 2011 y tuvo una duración de 21 días. Se utilizaron 15 vacas de la raza Holstein Neozelandés para analizar parámetros productivos y sanguíneos, las que fueron asignadas a un diseño completamente al azar con 3 tratamientos. Para el estudio de parámetros ruminales se utilizaron 3 vacas de la misma raza provistas de cánula ruminal, las que fueron asignadas a un diseño de cuadrado latino de 3x3, con tres tratamientos y tres periodos. Los tratamientos para ambos diseños fueron: T0, solo pastoreo; T2, pastoreo más 4 Kg diarios de concentrado compuesto en un 50% de maíz roleado al vapor y 50% avena entera y T3, pastoreo más 6 Kg diarios del mismo concentrado. Los animales fueron suplementados dos veces al día y realizaron pastoreo de tipo rotativo en franjas. El peso vivo y condición corporal fueron registrados durante todos los días. La producción de leche se registró los últimos cuatro días de cada semana y la composición de leche se analizó semanalmente. Las muestras de sangre y de líquido ruminal fueron recolectadas los dos últimos días de cada periodo, las muestras de sangre en la mañana y las ruminales durante mañana y tarde. En relación a parámetros metabólicos, el amoniaco ruminal disminuyó significativamente (P<0,05) con el aumento del nivel de concentrado (17,7; 15,0 y 13,9 mg·dl-1 para T0, T2 y T3). El amoniaco plasmático disminuyó (P<0,05) con la inclusión de concentrado pero no se observaron diferencias entre los niveles de concentrado (0,497; 0,416 y 0,391 mg·dl-1 para T0, T2 y T3). La concentración de urea plasmática disminuyó significativamente (P<0,05) al aumentar el concentrado (28,3; 26,2 y 21,8 mg·dl-1 para T0, T2 y T3). El peso vivo y la producción de leche no fueron afectados por los tratamientos (P>0,05). En términos de composición láctea, no se observaron diferencias estadísticamente significativas entre tratamientos (P>0,05), exceptuando la concentración de urea láctea, la que disminuyó significativamente (P<0,05) con el aumento de concentrado en la dieta (46,8; 42,3 y 36,3 mg·dl-1 para T0, T2 y T3) Bajo las condiciones en las que fue realizada esta investigación, se concluye que al aumentar el nivel de concentrado energético en la dieta de vacas lactantes consumiendo praderas de un alto contenido proteico, se reduce la concentración de amoniaco a nivel ruminal y sanguíneo, lo que provoca una disminución importante en los niveles de urea plasmática y láctea, sin provocar efectos significativos sobre los parámetros productivos. / A research was conducted at the Oromo Experimental Station, Department of Animal Production, Faculty of Agricultural Sciences, Universidad de Chile. The objective of this study was to evaluate the effect of energy supplementation on the metabolic and productive response of dairy cows fed pasture with high protein content and high degradability. The study was conducted during November and December of 2011 and lasted for 21 days. Fifteen Cows Holstein New Zealand randomly assigned to three treatments, were used to analyze blood, and productive parameter. For the study of rumen parameters three rumen fistulated cows were assigned to three treatments rotating during three periods under a 3 x 3 Latin square design. Treatments for both experiments were: T0, cows only grazing pasture; T2, grazing pasture plus 4 Kg/day of a concentrate composed of 50% corn and 50% oats and T3, grazing pasture plus 6 Kg/day of the same concentrate. Cows were supplemented twice a day and managed under a strip grazing system. Body weight and body condition were recorded every day. Milk production was recorded the last four days of each week and milk composition was analyzed weekly. Blood samples and ruminal fluid were collected the last two days of each period, blood samples in the morning and the rumen during morning and evening. Ruminal ammonia decreased significantly (P <0,05) as the level of concentrate was increased (17,7; 15,0 and 13,9 mg·dl-1 for T0, T2 and T3). Plasma ammonia decreased (P <0,05) with the inclusion of concentrate but no differences among levels of concentrate (0,497; 0,416 and 0,391 mg∙dl-1 for T0, T2 and T3) were found. Plasma urea concentration decreased significantly (P <0.05) as concentrate was increased (28,3 ; 26,2 and 21,8 mg∙dl-1 for T0, T2 and T3). Live weight and milk production were not affected by treatments (P>0,05). No statistical differences in milk composition, among treatments were found. (P> 0,05), except milk urea concentration, that decreased significantly (P <0.05) as concentrate was increased (46,8; 42,3 and 36,3 mg∙dl-1 for T0, T2 and T3). Under the conditions in which this research was conducted, it is concluded that increasing the level of an energy concentrate in the diet of lactating cows consuming pasture of a high protein content, reduces the concentration of ammonia in the rumen and blood, with a significant decrease in plasma urea and milk levels but without any significant effects on animal productive performance.

Se identificó la enfermedad Valvular Mitral Adquirida (EVMA) en muchos países de América Latina y el mundo entero. Esta enfermedad es una de las patologías cardiacas más frecuentes, presentándose mayormente en caninos seniles (mayores de 7 años) y en razas pequeñas. Caracteriza la Enfermedad Valvular Mitral Adquirida (EVMA) mediante el exámen clínico y pruebas complementarias como el estudio radiográfico, ecocardiográfico, hemograma, determinación de urea y creatinina en caninos. Se evaluó a 64 animales procedentes de la Clínica de Animales Menores durante el año 2013 y las muestras de sangre fueron procesadas en el Laboratorio de Patología Clínica de la FMV-UNMSM. Los resultados mostraron mayor frecuencia de la enfermedad en machos (61%) además de tener una población geriátrica con la enfermedad entre los 10 a menores de 13 años (43.8%) con pesos entre 2 a menores de 6 Kg (42.2%). Al examen físico todos presentaban un soplo cardiaco en diferentes intensidades y se observó en el estudio radiográfico y clínico que existía una asociación significativa entre los animales con tos e Índice Cardiaco (IC) (p= 0.006) y relación de desplazamiento traqueal y signo clínico de tos (p = 0.010), además de encontrar más pacientes cardiacos en la clasificación ISACHC II; mientras que en los exámenes de sangre (hemograma y determinación de urea y creatinina) no encontramos alteración alguna. Estos hallazgos determinan la importancia clínica para el diagnóstico y conocimiento de esta enfermedad en nuestro medio. / Tesis

In this study, a series of denim fiberboards are fabricated using two different resins, malamine urea formaldehyde (MUF) and polymeric methylene diphenyl diisocyanate (pMDI). Two experimental design factors (1) adhesive content and (2) MUF-pMDI weight ratio, were studied. All the denim fiberboard samples were fabricated following the same resin blending, cold-press and hot-press procedures. The physical and mechanical tests were conducted on the fiberboard following the procedures described in ASTM D1037 to obtain such as modulus of elasticity (MOE), modulus of rupture (MOR), internal bond (IB), thickness swell (TS), and water absorption (WA). The results indicated that the MOE was significantly affected by both factors. IB was affected significantly by weight ratio of different glue types, with 17 wt% more MDI resin portion in the core layer of the denim boards, the IB for total adhesive content 15% fiberboard was enhanced by 306%, while for total adhesive content 25% fiberboard, enhanced by 205%. TS and WA, with higher adhesive content used in denim boards' fabrication, and more pMDI portion in the core layer of the boards, the boards' TS and WA was reduced by up to 64.2% and 78.8%, respectively.

BACKGROUND: After proteolysis, the majority of released amino acids from dietary protein are transported to the liver for gluconeogenesis or to peripheral tissues where they are used for protein synthesis and eventually catabolized, producing ammonia as a byproduct. High ammonia levels in the brain are a major contributor to the decreased neural function that occurs in several pathological conditions such as hepatic encephalopathy when liver urea cycle function is compromised. Therefore, it is important to gain a deeper understanding of human ammonia metabolism. The objective of this study was to predict changes in blood ammonia levels resulting from alterations in dietary protein intake, from liver disease, or from partial loss of urea cycle function. METHODS: A simple mathematical model was created using MATLAB SimBiology and data from published studies. Simulations were performed and results analyzed to determine steady state changes in ammonia levels resulting from varying dietary protein intake and varying liver enzyme activity levels to simulate liver disease. As a toxicity reference, viability was measured in SH-SY5Y neuroblastoma cells following differentiation and ammonium chloride treatment. RESULTS: Results from control simulations yielded steady state blood ammonia levels within normal physiological limits. Increasing dietary protein intake by 72% resulted in a 59% increase in blood ammonia levels. Simulations of liver cirrhosis increased blood ammonia levels by 41 to 130% depending upon the level of dietary protein intake. Simulations of heterozygous individuals carrying a loss of function allele of the urea cycle carbamoyl phosphate synthetase I (CPS1) gene resulted in more than a tripling of blood ammonia levels (from roughly 18 to 60 μM depending on dietary protein intake). The viability of differentiated SH-SY5Y cells was decreased by 14% by the addition of a slightly higher amount of ammonium chloride (90 μM). CONCLUSIONS: Data from the model suggest decreasing protein consumption may be one simple strategy to decrease blood ammonia levels and minimize the risk of developing hepatic encephalopathy for many liver disease patients. In addition, the model suggests subjects who are known carriers of disease-causing CPS1 alleles may benefit from monitoring blood ammonia levels and limiting the level of protein intake if ammonia levels are high.

Winter wheat, with an annual average acreage of about 300,00o acres, forms an integral part of the farm economy of Utah. For many years intermountain agronomists and farmers alike have known dry-land wheat production to be limited by low summer rainfall. In the past 15 years, however, it has become apparent through intelligent research that in many cases lack of nitrogen has been the limiting factor. When this occurs, winter wheat production can be increased by correcting this nitrogen deficiency. It has also become apparent that a lack of nitrogen is responsible for much of the ppor quality wheat received by wheat processors form certain areas of the United States. To supple the neede nitrogen broth commercial fertilizers and green-manure crops have been used, but of particular importance at this time are commercial fertilizers. Unitl 1949 investigators of this problem used soil applications of either organic or inorganic nitrogen fertilizers in their studies. In that year Finney and Shellengerger (Kansas State College) began the first of their tests using "NuGreen" a synthetic urea fertilizer containing 44% nitrogen, as a foliage spray. Other experiemtns have shown that if large amounts of nitrogen fertilizer are added to dry farm wheat during a dry year, the yield may actually be reduced because the early vegetative growth is stimulated and the limited soil moisture is not able to bring about satisfactory maturity. It would seem that if nearly all of the nitrogen were withheld until the what was nearly mature, and then added as a spray, the danger of excessive early stimulation might be avoided while the protein content of the wheat might be increased. The results obtained by all of these tests were encouraging enough to warrant a study here in Utah of winter wheat fertilization involving the use of "NuGreen". It was proposed that the study be conducted on dry lands representative of intermountain conditions, and that it cover a two-year period. It was inteded that in the first year a preliminary of "feeler" test would be conducted to determine whether or not it was feasible to spray nitrogen on wheat. The intent was, that if favorable resutls were secured, this preliminary test would be followed in the second year by a more extensive study to obtian detailed information as to what effect urea spray might have on winter wheat. Objectives of these studies were: 1. To find the stage of maturity of the wheat plant at which urea spray would give the greatest protein increase. 2. To fidn the stage of matureity of the wheat plant at which urea spray would give the greatest yield increase. 3. To determine what amount of nitrogen, when supplied as urea, would tive the greatest stimulus to yield and protein, or both. 4. To compare the accepted practice of supplying nitrogen by soil application with the new method of adding it as a foliage spray.

No description available.