e moutsou use of english b2 for all exams keys

Ngày tải lên: 18/10/2014, 03:00

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Ngày tải lên: 30/03/2015, 14:29

Ngày tải lên: 05/09/2013, 10:15

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Ngày tải lên: 07/09/2013, 12:58

... possible in 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 ... extremely fragile, and generally not physiologically fully developed. For example, their small size (ie. small mouth size), the uncompleted development of their perception organs (ie. eyes, chemoreceptors) ... hatching yield large salmon larvae with large yolk sac supplies (ie. sufficient endogenous feed reserves for the first three weeks of their development), whereas first-feeding Gilthead seabream larvae...

Ngày tải lên: 15/12/2013, 00:15

... of feeding strategies and zootechnical aspects, still often results in less predictable culture performance. Despite extensive research efforts, the use of artificial diets in the culture of ... Use of micro-algae in aquaculture 2.6. Replacement diets for live algae 2.7. Literature of interest 2.8. Worksheets Peter Coutteau aboratory of Aquaculture & Artemia Reference Center ... spray-dried extract of Dunaliella salina. The latter may be used as a supplement to live algae to improve the growth of bivalve larvae. In addition, recent techniques have been developed for the large...

Ngày tải lên: 15/12/2013, 00:15

... approximately every four hours. It is believed that females can produce ten generations of offspring before they eventually die. The reproduction activity of Brachionus depends on the temperature of the ... shape of the lorica and the profile of the spines and ornaments allow the determination of the different species and morphotypes (see 3.4.). The rotifer’s body is differentiated inTO three distinct ... over 1000 species have been described, 90% of which inhabit freshwater habitats. They seldom reach 2 mm in body length. Males have reduced sizes and are less developed than females; some measuring...

Ngày tải lên: 15/12/2013, 00:15

... low levels. Appropriate techniques have thus been developed to improve the lipid profile of deficient Artemia strains, taking advantage of the indiscriminate filter-feeding behaviour of Artemia. ... seemed to be unlimited. However, with the expansion of aquaculture production in the 1970’s, the demand for Artemia cysts soon exceeded the offer and prices rose exponentially, turning Artemia ... or excellent larval food source that it has been credited with. Those cysts are available year-round in large quantities along the shorelines of hypersaline lakes, The coexistence of two species...

Ngày tải lên: 15/12/2013, 00:15

... reduced hatching or even complete mortality as a result of the toxicity of the chemical. However, in some cases no effect at all is observed. In general other diapause termination techniques ... pre-emergence embryonic development; subsequent dehydration of these cysts will in the worst case result in the killing of the differentiated embryos. Sufficiently dehydrated cysts only keep their ... packed cysts should be preferentially kept at low temperatures. However, when frozen, the cysts should be acclimated for one week at room temperature before hatching. 4.2.1.4. Diapause As...

Ngày tải lên: 15/12/2013, 00:15

... differences in survival were observed between treatments before the stress test, pronouned differences in PL-quality (expressed as their ability to survive the salinity stress applied) were observed ... deficient Artemia strains (see further). Commercial provisions of Artemia cysts containing high EPA levels are limited and consequently, these cysts are very expensive. Therefore, the use of ... 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 sometimes even earlier...

Ngày tải lên: 15/12/2013, 00:15

... draining the complete culture over a sieve which should be partially submerged. The Artemia should be thoroughly washed preferentially in freshwater or otherwise in seawater. The harvested Artemia ... for the short-term intensive culture of Artemia juveniles for use as a nursery diet for fish and shrimp was developed at the ARC. The idea was to develop a flexible culture procedure, covering ... proportionally smaller welded-wedge filters can be used, leaving more volume for the animals in the culture tank. Furthermore, they are cost-effective since they do not wear out. As brine shrimp...

Ngày tải lên: 15/12/2013, 00:15

... recommended. Different screens, each with a smaller mesh size than the previous one, are placed one after the other. Screens with a large mesh size are best installed before the pumps, while ... storage. deactivating methods used are described in chapter 4.2.1.4. However, before implementing any of these techniques, they should be tested for effectiveness. Figure 4.5.21. The effect of ... 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 a stainless-steel welded-wedge...

Ngày tải lên: 15/12/2013, 00:15

... anything else. The effectiveness of filtering is also influenced by the mesh size of the net: the denser the net the faster it will clog, hence, the smaller its effectiveness. It is therefore necessary ... be aware that the greater the surface area of the net the more effective and rapid the filtration. Hence, the upper limit of the dimensions of the nets depends on the ease of handling rather ... due to the narrow and strong back current. The longer the distance between the propeller and the net, the wider and shorter the net can be. The distance between the propeller and the net generally...

Ngày tải lên: 15/12/2013, 00:15

... larvae. Cryopreserved trochophores are also commercially available as Trochofeed (Cryofeeds Ltd., Canada). They are produced from certified disease-free broodstock oysters of selected genetic strains. ... top of the tube, where they can be collected with the use of a pipet onto a 100 àm mesh screen. After rinsing with seawater, the nematodes can then be fed to the larval predators. Table 6.3. ... algal requirements and to estimate the harvesting time, regular sampling of the population density must be routinely undertaken. Harvesting techniques can be non-selective irrespective of size or...

Ngày tải lên: 15/12/2013, 00:15

Ngày tải lên: 21/12/2013, 01:19

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Ngày tải lên: 12/02/2014, 12:01

... confounders, or most likely corpus differences between Gigaword and the sub- set of FrameNet they evaluated. Ultimately we have found that complex models for selectional preferences may not be necessary, depending ... than because of containing low-frequency argument heads. Given the large amount of seen data, we be- lieve evaluations should include all data examples to best represent the corpus. We describe our ... so for best performance. A noun’s representative vector consists of verb slots and the number of times the noun was seen in each slot. We removed any verb slot not seen more than x times, where...

Ngày tải lên: 07/03/2014, 22:20