980 resultados para R package
Resumo:
The amphipods are major food items for many commercial fishes, and they are used as protein food for agricultural animals. In the present paper are presented the results of four-year observations on the feeding of Gammarus balcanicus in nature and in an aquarium. Among the studied aspects were the dependence of daily food ration on sex and physiological state (with and without eggs) and feeding on different kinds of plant food. The study concludes that Gammarus balcanicus willingly feed on soft half-decayed plant residues; into their ration also enters food of animal origin. In contrast to other amphipods, G. balcanicus eats representatives of its own species very rarely, and only dead or immobile ones.
Resumo:
O presente trabalho avaliou o potencial da enzima HRP no descoramento dos corantes têxteis: Azul Drimaren X-3LR (DMBLR), Azul Drimaren X-BLN (DMBBLN), Rubinol Drimaren X-3LR (DMR) e Azul Drimaren CL-R (RBBR). Parâmetros como concentração do corante, temperatura, concentração de peróxido de hidrogênio (H2O2) e tempo de reação foram otimizados. Os ensaios de descoramento dos corantes foram realizados a partir desses resultados. As melhores condições reacionais determinadas para os corantes estudados foram: concentração do corante = 120 mg L-1, temperatura = 35C, concentração de H2O2 = 0,55 mM e tempo de reação = 1 hora. Os percentuais de descoramento dos corantes DMBLR, DMBBLN, DMR e RBBR, após o tratamento enzimático foi de 99, 77, 94 e 97%, respectivamente. O tempo reacional de 5 minutos foi suficiente para os corantes DMBLR e RBBR apresentarem elevada porcentagem de descoramento, 96% para ambos. Já os corantes DMBBLN e DMR só apresentaram elevado grau de descoramento após 1 hora de reação, sendo o corante DMBBLN o mais recalcitrante, apresentando uma melhora de 10% na porcentagem de descoramento, após 24 horas de reação. Além do grau de descoramento, também foi avaliada a toxicidade dos corantes antes e após o tratamento enzimático utilizando Daphnia pulex e Artemia salina como bioindicadores de toxicidade. Resultados toxicológicos utilizando Daphnia pulex não foram conclusivos, indicando que esse bioindicador não foi adequado para avaliar a toxicidade dos corantes estudados no meio reacional utilizado. Com o uso da Artemia salina na avaliação toxicológica foi observado uma redução da toxicidade para os corantes DMBLR, DMR e RBBR após tratamento enzimático, e um aumento da toxicidade não significativo para o corante DMBBLN. Os resultados obtidos no trabalho ressaltam a eficiência da enzima HRP no descoramento dos corantes têxteis estudados, sem a geração de produtos tóxicos e prejudiciais ao meio ambiente
Resumo:
Methods of filtering an n.m.r. spectrum which can improve the resolution by as much as a factor of ten are examined. They include linear filters based upon an information theory approach and non-linear filters based upon a statistical approach. The appropriate filter is determined by the nature of the problem. Once programmed on a digital computer they are both simple to use.
These filters are applied to some examples from 13C and 15N n.m.r. spectra.
Resumo:
A study has been made primarily of the food of the chironomid Procladius nigriventris: this includes Alona affinis, Bosmina coregoni, Camptocercus, Eucyclops serrulatus, Paracyclops fimbriatus, Acanthocyclops viridis, Harpacticoida, Diaptomus graciloides, Ostracods, Chironomus sp, Polypedilum sp and Tanytarsus sp. Chironomus larvae usually found in the gut are in their 1st or 2nd instars , though occasional 3rd instars are present. The study summarises other findings on the feeding behaviour of Procladius nigriventris.
Resumo:
Three ponds were chosen for this study. The two lower ones were of 2 - 4 hectares in area, the depth of the littoral zone was 2.5 - 3 metres at the time of maximum flooding and the mud which covered the floor of the ponds was homogeneous and autochthonous in nature with very few vegetable remnants. The ponds which were originally set up in 1950. were intended for water supply and populated with Crucian Carp (for human consumption). A survey was done in the ponds in order to establish number and biomass of Tendipes semireductus. The author concludes that in these ponds T.semireductus has 2-3 generations per year.
Resumo:
Laboratory research was done in order to study the feeding of larval Cricotopus silvestris F. in relation to characters of structure of oral apparatus. Results of the experiments are summarised and the oral apparatus morhologically described.
Resumo:
There is at the moment no direct method of determining the organic matter content of natural waters. In 1940/41 8 different water bodies in central Russia were studied and their organic matter identified. The author concludes that there is currently no easy method to determine organic matter in water. A number methods need to be applied.
Resumo:
The report describes the results of preliminary analyses of data obtained from a series of water temperature loggers sited at various distances (0.8 to 21.8 km) downstream of Kielder dam on the River North Tyne and in two natural tributaries. The report deals with three aspects of the water temperature records: An analysis of an operational aspect of the data sets for selected stations, a simple examination of the effects of impoundment upon water temperature at or close to the point of release, relative to natural river temperatures, and an examination of rate of change of monthly means of daily mean, maximum, minimum and range (maximum - minimum) with distance downstream of the point of release during 1983.
Resumo:
Mediante Western blot y cultivos celulares, en el presente trabajo se han observado las variaciones en el número de espinas dendríticas y sinapsis en neuronas del hipocampo de ratas macho de tres meses de edad, cuando se activa o se inhibe el receptor de neurokinina 3 (NK3-R) mediante drogas agonistas o antagonistas. Se ha visto que el gen de este receptor tiene una menor expresión en ratas muy ansiosas en comparación con las poco ansiosas, por lo que se pretende estudiar las implicaciones que pueda tener esta proteína en el trastorno de ansiedad.
Resumo:
This report describes the general background to the project, defines the stations from which data sets have been obtained and lists the available data. The project had the following aims: To develop a more accurate and less labour-intensive system for the collection and processing of water temperature data from a number of stations within a stream/river system, and to use the River North Tyne downstream of the Kielder impoundment as a test bed for the system. This should yield useful information on the effects of impoundment upon downstream water temperatures.
Resumo:
IDOKI SCF Technologies S.L. is a technology-based company, set up on September 2006 in Derio (Biscay) with the main scope of developing extraction and purification processes based on the use of supercritical fluid extraction technology (SFE) in food processing, extraction of natural products and the production of personal care products. IDOKI¿s researchers have been working on many different R&D projects so far, most of them using this technology. However, the optimization of a SFE method for the different matrices cannot be performed unless we have an analytical method for the characterisation of the extracts obtained in each experiment. The analytical methods are also essential for the quality control of the raw materials that are going to be used and also for the final product. This PhD thesis was born to tackle this problem and therefore, it is based on the development of different analytical methods for the characterisation of the extracts and products. The projects that we could include in this thesis were the following: the extraction propolis, the recovery of agroindustrial residues (soy and wine) and the dealcoholisation of wine.On the one hand, for the extraction of propolis, several UV-Vis spectroscopic methods were used in order to measure the antioxidant capacity and the total polyphenol and flavonoid content of the extracts. A SFC method was also developed in order to measure more specific phenolic compounds. On the other hand, for the recovery of agroindustrial residues UV-Vis spectroscopy was used to determine the total polyphenol content and two SFC methods were developed to analyse different phenolic compounds. Extraction methods such as MAE, FUSE and rotary agitation were also evaluated for the characterisation of the raw materials.Finally, for the dealcoholisation of wine, the development of a SBSE-TD-GC-MS and DHS-TD-GC-MS methods for the analysis of aromas and a NIR spectroscopic method for the determination of ethanol content with the help of chemometrics was necessary. Most of these methods are typically used in IDOKI¿s lab as routine analyses apart from others not included in this PhD thesis.
Resumo:
R puede entenderse como un lenguaje de programación, como un potente software de análisis estadísticos o incluso como un generador de gráficos. Cualquiera de las tres acepciones es compatible con una definición de R. Estas páginas ofrecen al lector interesado y no iniciado en programación, los conceptos básicos y necesarios de la sintaxis de R que le permitirán trabajar en un entorno pensado para su uso con interfaces de códigos. Si bien es cierto que existen interfaces gráficas (R Commander) que facilitan el uso de R como software para el análisis de datos, no es menos cierto que la adquisición de destrezas en el manejo de unas normas de sintaxis básicas permitirán al usuario de R beneficiarse aún más de la potencia y de las ventajas que ofrece este entorno.