use of english b2 for all exams keys

Ngày tải lên: 18/10/2014, 03:00

Ngày tải lên: 12/02/2015, 18:00

Ngày tải lên: 16/02/2015, 00:00

Ngày tải lên: 30/03/2015, 14:29

Ngày tải lên: 05/09/2013, 10:15

Ngày tải lên: 05/09/2013, 10:17

Ngày tải lên: 07/09/2013, 12:58

... plankton for feeding in commercial hatcheries may therefore appear evident, in practice the use of natural plankton often entails many constraints which will be explained in detail in chapter 5. For ... and use of live food organisms as feed for the developing larvae. The present manual describes the major production techniques currently employed for the cultivation of the major types of live ... recent years through the development and use of a succession of live food organisms as feed for the developing larvae. The aim of the present manual was therefore to review and summarise the latest...

Ngày tải lên: 15/12/2013, 00:15

... commercial rearing of various species of marine animals as a food source for all growth stages of bivalve molluscs, larval stages of some crustacean species, and very early growth stages of some fish ... culture performance. Despite extensive research efforts, the use of artificial diets in the culture of bivalve molluscs is still very limited. The advantages and disadvantages of each of the three ... and failure of cells to separate after cell division may be possible sources of erroneous counts. Counting with a microscope has the advantage of allowing control of the quality of the cultures....

Ngày tải lên: 15/12/2013, 00:15

... generations of offspring before they eventually die. The reproduction activity of Brachionus depends on the temperature of the environment as illustrated in Table 3.1. The life cycle of Brachionus ... The rotifers are rinsed, a small part is used for maintenance of the stock, and the remaining rotifers can be used for upscaling. Furthermore, after some months of regular culture the stock ... especially designed for protein enrichment in rotifers. The high levels of proteins allow the cultures to continue to grow and to develop during the enrichment period. Normally it is used in...

Ngày tải lên: 15/12/2013, 00:15

... affecting the parental generation. For optimal use of Artemia in aquaculture the hatching characteristics of any batch of cysts being used should be known. More information in this respect is given ... affect the abundance of the population and eventually cause a temporary absence of the species. As Artemia is incapable of active dispersion, wind and waterfowl (especially flamingos) are ... expansion of aquaculture production in the 1970’s, the demand for Artemia cysts soon exceeded the offer and prices rose exponentially, turning Artemia into a bottleneck for the expansion of the...

Ngày tải lên: 15/12/2013, 00:15

... 4.2.4. Direct use of decapsulated cysts The direct use of Artemia cysts, in its decapsulated form, is much more limited in larviculture of fish and shrimp, compared to the use of Artemia nauplii. ... higher than for instar I nauplii (see 4.2.3.; Fig. 4.3.4.). For example, for the culture of carp larvae during the first two weeks, the use of decapsulated cysts constitutes a saving of over one ... hatching of small quantities of Artemia cysts is basically very simple, several parameters need to be taken into consideration for the successful hatching of large (i.e. kilogram) quantities of cysts,...

Ngày tải lên: 15/12/2013, 00:15

... hatcheries all over the world for enhancing the nutritional value of Artemia with essential fatty acids. Figure 4.3.7. Schematic diagram of the use of Artemia as vector for transfer of specific ... Penaeid shrimp Artemia is generally used for feeding the late larval and postlarval stages of penaeids. Freshly-hatched nauplii are usually offered at the start of the first mysis stage, and ... shading the upper part of the hatching tank (use of cover) and focusing a light source on the transparent conical part of the bottom. Nauplii should not be allowed to settle for too long (i.e.,...

Ngày tải lên: 15/12/2013, 00:15

... seawater formulations used for tank production of Artemia (ing.l -1 ). For the Dietrich and Kalle formulation, solutions A and B are prepared separately, then mixed and strongly aerated for 24h. ... and adults are used as a nursery diet not only for their optimal nutritional value but also for energetic advantages as well. For example, when offered large Artemia instead of freshly-hatched ... production capacities. Application of an that takes profit of the specific aspects of ongrown Artemia: instead of adding the enrichment emulsion at the end of the culture, it is distributed...

Ngày tải lên: 15/12/2013, 00:15

... the culture ponds. The same type of filters as described for large salt operations can be used. Moreover, the small size of the ponds allows the use of so-called filter boxes. In such a box ... ponds are often turned into fish/shrimp ponds. for dilution due to release of water from the cysts. - for a low ratio of cysts to brine (e.g. use of brine ponds or large tanks), exchange of brine ... reduced by composting the manure before use. One of the main disadvantages of organic fertilizers is their bulk, which causes high transportation and labour costs. Often special facilities where...

Ngày tải lên: 15/12/2013, 00:15

... weight of Tigriopus can be harvested during 89 days at maximal densities of 22,000 animals.l -1 ; the amount of yeast used for a 1 kg production of Tigriopus being 5 to 6 kg. 5.2.6. Use of resting ... cycle of Daphnia 6.1.2. Nutritional value of Daphnia 6.1.3. Feeding and nutrition of Daphnia 6.1.4. Mass culture of Daphnia 6.1.5. Production and use of resting eggs 6.1.6. Use of Moina ... stimulus for many fish which prefer them over rotifers. Another advantage of the use of copepods, especially benthos-type species like Tisbe, is that the non-predated copepods keep the walls of the...

Ngày tải lên: 15/12/2013, 00:15

... value of Daphnia 6.1.3. Feeding and nutrition of Daphnia 6.1.4. Mass culture of Daphnia 6.1.5. Production and use of resting eggs 6.1.6. Use of Moina 6.1.1. Biology and life cycle of Daphnia ... and use of resting eggs Resting eggs are interesting material for storage, shipment and starting of new Daphnia cultures. The production of resting eggs can be initiated by exposing a part of ... used to fortify the nematodes with therapeutics (bio-medication). For example, nematodes can be placed in 1 l beakers with 500 ml of fresh artificial seawater and 5 g of Romet-30 premix (Hoffman...

Ngày tải lên: 15/12/2013, 00:15

Ngày tải lên: 21/12/2013, 01:19

Ngày tải lên: 12/02/2014, 12:01