Active reservoir management: a model solution

Steady-state procedures, of their very nature, cannot deal with dynamic situations. Statistical models require extensive calibration, and predictions often have to be made for environmental conditions which are often outside the original calibration conditions. In addition, the calibration requirement makes them difficult to transfer to other lakes. To date, no computer programs have been developed which will successfully predict changes in species of algae. The obvious solution to these limitations is to apply our limnological knowledge to the problem and develop functional models, so reducing the requirement for such rigorous calibration. Reynolds has proposed a model, based on fundamental principles of algal response to environmental events, which has successfully recreated the maximum observed biomass, the timing of events and a fair simulation of the species succession in several lakes. A forerunner of this model was developed jointly with Welsh Water under contract to Messrs. Wallace Evans and Partners, for use in the Cardiff Bay Barrage study. In this paper the authors test a much developed form of this original model against a more complex data-set and, using a simple example, show how it can be applied as an aid in the choice of management strategy for the reduction of problems caused by eutrophication. Some further developments of the model are indicated

Modelling algal blooms

This is the final report on the research project to develop predictive models to quantify algal blooms in relation to environmental variables. The project's objectives were to develop models simulating the impact of vertical structure and mass transfer upon the dynamics of planktonic algae, including cyanobacteria, in lakes and reservoirs, to assess the potential of sedimentary phosphorus to sustain algal growth following reduction in external loading and to expand and enhance formulations to predict behaviour of blue-green algal populations and to incorporate these into a model software package. As part of the project a strategy for the production of a user-friendly packaging for the modelling software PROTEC-2 adaptable to particular sites was developed

Efeito da suplementação enzimática em rações com farelo de soja e soja integral extrusada sobre a digestibilidade de nutrientes, o fluxo de nutrientes na digesta ileal e o desempenho de frangos Enzymatic supplementation on soybean meal and full fat extruded soybean based diet on the digestibility of nutrients, ileal digest flow and broiler performance

Três experimentos foram realizados com o objetivo de avaliar o efeito da suplementação enzimática em rações à base de milho e soja sobre o desempenho (Experimento 1), a digestibilidade de nutrientes (Experimento 2) e o desempenho e o fluxo de nutrientes na digesta ileal (Experimento 3) em frangos de corte. No Experimento 1, para o cálculo das rações experimentais, a composição química do farelo de soja (FS) e da soja integral extrusada (SIE) foi superestimada em 7% para os valores de EM e PB e 5% para Met, Met+Cis e Lis (Trat. C, D e E) e 9% para EM, 7% para PB e 5% para Met, Met+Cis e Lis (Trat. F, G e H), quando houve a adição de enzimas (Allzyme Vegpro<FONT FACE=Symbol>â</FONT> e Allzyme Lipase<FONT FACE=Symbol>â</FONT>). Conclui-se que os valores de EM, PB e aminoácidos (Met, Met+Cis e Lis) da soja puderam ser superestimados em 9, 7 e 5%, respectivamente, quando houve a adição de complexo multienzimático (Allzyme Vegpro<FONT FACE=Symbol>â</FONT>) às rações para frangos de corte (1-42 dias), sem prejuízo ao desempenho das aves. Os tratamentos utilizados nos experimentos 2 e 3 foram: A e B - rações contendo farelo de soja (FS), sem e com adição de complexo multienzimático (Allzyme Vegpro<FONT FACE=Symbol>â</FONT>); e C e D - rações contendo farelo de soja (FS) e soja integral extrusada (SIE), sem e com adição de complexo multienzimático (Allzyme Vegpro<FONT FACE=Symbol>â</FONT>). No experimento 2, não foram observadas diferenças entre os tratamentos para os coeficientes de metabolização aparente de matéria seca, proteína bruta, energia bruta e a EMAn. No Experimento 3, para os períodos inicial (1-21 dias de idade), de crescimento (22-42 dias de idade) e total (1-42 dias de idade), não foram observadas diferenças no consumo de ração, no ganho de peso e na conversão alimentar das aves que receberam rações suplementadas com enzimas. Na determinação do fluxo de nutrientes na digesta ileal, não foram verificadas diferenças entre os tratamentos estudados, aos 21 e 42 dias de idade.<br>Three trials were conducted to evaluate the effect of enzymatic supplementation of corn and soybean based diets on performance (Trial 1), nutrients digestibility (Trial 2), performance and nutrient flow in the ileal digesta (Trial 3) in broiler chickens. In Trial 1, for experimental diet formulation, the chemical composition of soybean meal (SM) and full fat extruded soybean (ES) were overestimated in 7% for ME and CP, and 5% for Met, Met+Cys and Lys (Treatment C, D, and E) and 9% for ME, 7% for CP and 5% for Met, Met+Cys and Lys (Treatments F, G e H) when there was enzymes addition (Allzyme Vegpro<FONT FACE=Symbol>â</FONT> e Allzyme Lipase<FONT FACE=Symbol>â</FONT>). It was concluded that ME, CP and amino acids (Met, Met+Cys and Lys) values can be overestimated in 9, 7 and 5%, respectively, when there was the addition of enzymatic complex to the broilers diets (1-42 days), without reducing bird performance. Treatments used on trials 2 and 3 were: A and B - diets based on soybean meal (SBM) with and without addition of multienzymatic complex (Allzyme Vegpro<FONT FACE=Symbol>â</FONT>) and C and D - diets based on soybean meal (SBM) and full fat extruded soybean (ES) with and without addition of multienzymatic complex (Allzyme Vegpro<FONT FACE=Symbol>â</FONT>). In Trial 2 differences were not observed among treatments for coefficients of apparent metabolization of dry matter, crude protein, gross energy and AMEn. In trial 3, for initial period (1-21 days), growth period (22-42 days) and total period (1-42 days) differences were not observed in feed intake, weight gain and feed: gain among birds fed with diets supplemented with enzymes. In the determination of nutrient flow in ileal digesta, differences among studied treatments were not observed, for 21 and 42 days age