Avaliação do uso de identificadores eletrônicos em suínos

Nowadays the consumer market demands a gradually increase in the products' quality control. The manual control that exits, used in animal production, shows ineficiency in warrating an increasing percentual of the desirable quality, so this can only be reached when an effective animal tracebility system is applied, from birth to slaughter. Individual electronic identification presents high importance in this focus, providing information recorded directly from the animal. Electronic traceability uses electronic devices that emit a signal activated by a fixed reader placed where it is needed to record a certain event, or uses a manual reader which allows a higher independence of the operator. Knowing the importance of the electronic identification as a tool for applying traceability in animal production, this research had as objective to evaluate the use of transponders in order to garantee the manual reading as well as the fixed antenna reading. The following implant places were analized in piglet, just after their birth: 1) forehead, 2) external ear lobule, 3) the posterior auricular base, and 4) a transponder inserted in a earing implanted in the ear lobule. The factors of skin damage and migration were analized, as well as the reading efficiency. It was found that the best implant place was the posterior ear base.

Uso de redes neurais artificiais na identificação de vocalização de suínos

Animal welfare has been an important research topic in animal production mainly in its ways of assessment. Vocalization is found to be an interesting tool for evaluating welfare as it provides data in a non-invasive way as well as it allows easy automation of process. The present research had as objective the implementation of an algorithm based on artificial neural network that had the potential of identifying vocalization related to welfare pattern indicatives. The research was done in two parts, the first was the development of the algorithm, and the second its validation with data from the field. Previous records allowed the development of the algorithm from behaviors observed in sows housed in farrowing cages. Matlab® software was used for implementing the network. It was selected a retropropagation gradient algorithm for training the network with the following stop criteria: maximum of 5,000 interactions or error quadratic addition smaller than 0.1. Validation was done with sows and piglets housed in commercial farm. Among the usual behaviors the ones that deserved enhancement were: the feed dispute at farrowing and the eventual risk of involuntary aggression between the piglets or between those and the sow. The algorithm was able to identify through the noise intensity the inherent risk situation of piglets welfare reduction.

Relação dose-dependente do uso crônico de fenitoína e atrofia cerebelar em pacientes com epilepsia

The chronic treatment with phenytoin or the acute intoxication by this drug may cause permanent cerebellar injury with atrophy of cerebellum vermis and hemispheres, which can be detected by neuroimaging studies. The aim of the present study was to investigate the correlation between the dosage and duration of treatment with phenytoin and the occurrence of cerebellar atrophy. Sixty-six patients were studied and had their tomographies analyzed for cerebellar atrophy. Of the 66 patients studied, 18 had moderate/severe atrophy, 15 had mild atrophy and 33 were considered to be normal. The patients with moderate/severe atrophy were those with higher exposure to phenytoin (longer duration of treatment and higher total dosage) showing statistically significant difference when compared to patients with mild atrophy or without atrophy (p=0.02). Further, the patients with moderate/severe atrophy had serum levels of phenytoin statistically higher than those of patients with mild atrophy or without atrophy (p = 0.008). There was no association between other antiepileptic drugs dosage or duration of treatment and degree of cerebellar atrophy. We also found that older patients had cerebellar atrophy more frequently, indicating that age or duration of the seizure disorder may also be important in the determination of cerebellar degeneration in these patients. We conclude that although there is a possibility that repeated seizures contribute to cerebellar damage, long term exposure to phenytoin, particularly in high doses and toxic serum levels, cause cerebellar atrophy.

Uso de membranas de Nafion para a construção de sensores ópticos para medidas de pH

The behaviour of Nafion® polymeric membranes containing acid-base dyes, bromothymol blue (BB) and methyl violet (MV), were studied aiming at constructing an optical sensor for pH measurement. BB revealed to be inadequate for developing sensing phases due to the electrostatic repulsion between negative groups of their molecules and the negative charge of the sulfonate group of the Nafion®, which causes leaching of the dye from the membrane. On the other hand, MV showed to be suitable due to the presence of positive groups in its structure. The membrane prepared from a methanolic solution whose Nafion®/dye molar ratio was 20 presented the best analytical properties, changing its color from green to violet in the pH range from 0.6 to 3.0. The membrane can be prepared with good reproducibility, presenting durability of ca. 6 months and response time of 22 s, making possible its use for pH determination in flow analysis systems.

Novos sorventes baseados em poli (metiloctilsiloxano) sobre sílica para uso em extração em fase sólida

This paper presents an easy and practical procedure to obtain silica-based C-8 type sorbents for use in solid-phase extraction. The materials are prepared by depositing poly(methyloctylsiloxane), PMOS, on the silica support. Two different treatments for immobilization were used: thermal treatment or gamma irradiation. Suitable recoveries were obtained after pre-concentration of dilute solutions, at the ng/L level, of a mixture of pesticides, indicating the good performance of the materials.

Alteração da atividade enzimática em organismos aquáticos por poluentes de origem agrícola: uma abordagem geral e sobre a suscetibilidade da fosfatase ácida

The input of agrochemicals in the aquatic compartment can results in biochemical injuries for living organisms. In this context, the knowledge of alterations of enzymatic activities due the presence of agriculture pollutants contributes for the elucidation of the mechanisms of toxicity, implementation of economic methods for monitoring purposes and establishment of maximum allowed concentrations. In the present work, the above considerations are discussed, and data concerning changes in enzymatic function by pesticides and fertilizer contaminants are reviewed. Also, we focused on the acid phosphatase due its susceptibility to several pollutants and diversity in cellular functions.

Possibilidades e limitações no uso da temperatura em cromatografia líquida de fase reversa

High-temperature liquid chromatography (HTLC) is a technique that presents a series of advantages in liquid phase separations, such as: reduced analysis time, reduced pressure drop, reduced asymmetry factors, modified retentions, controlled selectivities, better efficiencies and improved detectivities, as well as permitting green chromatography. The practical limitations that relate to instrumentation and to stationary phase instability are being resolved and this technique is now ready to be applied for routine determinations.

Uso de perfis cromatográficos de voláteis de cafés arábicas torrados para a diferenciação das amostras segundo o sabor, o aroma e a qualidade global da bebida

In this work, the volatile chromatographic profiles of roasted Arabica coffees, previously analyzed for their sensorial attributes, were explored by principal component analysis. The volatile extraction technique used was the solid phase microextraction. The correlation optimized warping algorithm was used to align the gas chromatographic profiles. Fifty four compounds were found to be related to the sensorial attributes investigated. The volatiles pyrrole, 1-methyl-pyrrole, cyclopentanone, dihydro-2-methyl-3-furanone, furfural, 2-ethyl-5-methyl-pyrazine, 2-etenyl-n-methyl-pyrazine, 5-methyl-2-propionyl-furan compounds were important for the differentiation of coffee beverage according to the flavour, cleanliness and overall quality. Two figures of merit, sensitivity and specificity (or selectivity), were used to interpret the sensory attributes studied.

Determinação da densidade de corrente de corrosão em meios de baixa condutividade: uso de microeletrodos para minimizar a queda ôhmica

The gravimetric and electrochemical tests are the most common techniques used in determining the corrosion rate. However, the use of electrochemical polarization is limited to electrolytes with sufficient conductivity for which Tafel curves are linear. In this study, we investigated a technique in which working microelectrodes of AISI 1020 steel were used to obtain the Tafel curves in diesel oil. The strategy was to reduce the electrode area and hence the ohmic drop. The diameter of the microelectrode was reduced to a value where the compensation of the Tafel curves became unnecessary. The results showed that for electrodes with diameters below 50 μm, the ohmic drop tends to a minimum and independent of the microelectrode diameter.

Índice de previsão de produção de leite para vacas Jersey

In Brazil the adoption of several models of cattle confinement leads to special conditions for management methods in dairy production, which can be improved by the use of technology that assures better herd management. Indexes relating environmental variables to production are applied for the prediction of milk production. The values of temperature and relative humidity, rain index, solar radiation and pasture soil temperature are generally considered potential stress agents for cows. The objective of this research was to develop an index for predicting milk production for high productivity Jersey milking cows lodged in semi confinement in tropical conditions. The experiment considered two treatments: A - the cows waited for 30 minutes prior to milking in a room with a shower associated to a fan; B - the cows did not have access to this room (control). Other than the waiting period, the cows had access to pasture. Differences in the effect of average production were not statistically significant. The analysis for studying the effect of the variables and designing the model led to a statistical model relating the variables milk production and rain index, as well as the maximum soil temperature of pasture, and milk production.

Modelagem matemática e simulação numérica do resfriamento rápido de morango com ar forçado

This work approaches the forced air cooling of strawberry by numerical simulation. The mathematical model that was used describes the process of heat transfer, based on the Fourier's law, in spherical coordinates and simplified to describe the one-dimensional process. For the resolution of the equation expressed for the mathematical model, an algorithm was developed based on the explicit scheme of the numerical method of the finite differences and implemented in the scientific computation program MATLAB 6.1. The validation of the mathematical model was made by the comparison between theoretical and experimental data, where strawberries had been cooled with forced air. The results showed to be possible the determination of the convective heat transfer coefficient by fitting the numerical and experimental data. The methodology of the numerical simulations was showed like a promising tool in the support of the decision to use or to develop equipment in the area of cooling process with forced air of spherical fruits.

Modelo dinâmico de simulação e otimização da força normal de reação do solo para um mecanismo de corte basal

The physical model was based on the method of Newton-Euler. The model was developed by using the scientific computer program Mathematica®. Several simulations where tried varying the progress speeds (0.69; 1.12; 1.48; 1.82 and 2.12 m s-1); soil profiles (sinoidal, ascending and descending ramp) and height of the profile (0.025 and 0.05 m) to obtain the normal force of soil reaction. After the initial simulations, the mechanism was optimized using the scientific computer program Matlab® having as criterion (function-objective) the minimization of the normal force of reaction of the profile (FN). The project variables were the lengths of the bars (L1y, L2, l3 and L4), height of the operation (L7), the initial length of the spring (Lmo) and the elastic constant of the spring (k t). The lack of robustness of the mechanism in relation to the variable height of the operation was outlined by using a spring with low rigidity and large length. The results demonstrated that the mechanism optimized showed better flotation performance in relation to the initial mechanism.

Avaliação de tipos de ventilação em maternidade de suínos

Livestock facilities, where animals carry their productive cycle, must have as main characteristic, the control of influence over climatic factors on animals. The environment variations can be controlled through the use of different ventilation systems. The objective of this research was to evaluate the influence of different environment conditioning systems on swine nursery. Three treatments have been tested: natural ventilation, cooled ventilation and forced ventilation. The climatic parameters evaluated were: air temperature, relative humidity and black globe temperature. The physiological parameters analyzed were: respiratory frequency and back fat thickness. Number of born alive piglets, average weight at weaning and number of weaned piglets were also evaluated parameters. The use of cooled ventilation systems were able to decreased animal's air temperature and respiratory frequency, and the black globe temperature and humidity index (WBGT) and the radiating thermal load (RTL).

Desempenho físico-mecânico de minipainéis de terra crua tratada com aditivos químicos

The aim of this research was to study the effect of chemical additives (lime and Portland cement) associated with sodium silicate on soil in order to obtain compressed soil bricks. Mini panels were constructed with such bricks being their physical and mechanical characteristics determined in laboratory conditions and their behavior evaluated through the association of destructive and non-destructive methods. For this purpose a sandy soil and a finely divided one were added to Portland cement and lime in the dosage of 6% and 10% taken in dry weight basis in relation to the dry soil. The sodium silicate dosage of 4% was also taken in dry weight basis in relation to the dry soil-cement or to the dry soil-lime. The compressed soil bricks were cured in a humidity chamber for 7; 28; 56 and 91 days. The bricks were laid on the fourteenth day to form prismatic mini panels each one with four layers of bricks. After 28; 56 and 91 days the mini panels were submitted to both; ultrasonic and compressive tests to determine its elastic properties (dynamic modulus) and the compressive resistance. The best results in terms of compressive strength, water absorption capacity or dynamic elastic modulus, were reached by the sandy soil added to 10% of Portland cement or lime associated with sodium silicate.

Efeitos da cobertura do solo com filme de polietileno azul no consumo de água da cultura da alface cultivada em estufa

The covering of the soil is an agricultural practice that intends to control the harmful herbs, to reduce the losses of water by evaporation of the soil, and to facilitate the harvest and the commercialization, once the product is cleaner and healthier. However, when the soil is covered important microclimatic parameters are also altered, and consequently the germination of seeds, the growth of roots, the absorption of water and nutrients, the metabolic activity of the plants and the carbohydrates storage. The current trial intended to evaluate the effect of soil covering with blue colored film on consumptive water-use in a lettuce crop (Lactuca sativa, L.). The experiment was carried out in a plastic greenhouse in Araras - São Paulo State, Brazil from March 3rd, 2001 to May 5th, 2001. The consumptive water-use was measured through two weighing lysimeter installed inside the greenhouse. Crop spacing was 0.25 m x 0.25 m and the color of the film above soil was blue. Leaf area index (IAF), was measured six times (7; 14; 21; 28; 35; 40 days after transplant) and the water-use efficiency (EU) was measured at the end. The experimental design was subdivided portions with two treatments, bare soil and covered soil. The average consumptive water-use was 4.17 mm day-1 to the bare soil treatment and 3.11 mm day-1 to the covered soil treatment. The final leaf area index was 25.23 to the bare soil treatment and 24.39 to the covered soil treatment, and there was no statistical difference between then.