Yield limiting factors

Yield limiting factors (YLFs) that cannot be controlled in the field will not be affected by precision farming methods. Natural rainfall, sunlight hours, humidity, COj levels and air temperature are variables that cannot be altered. Soil temperature and soil texture can be affected by husbandry, but only over a long period, sometimes decades. 

For given operating conditions and submergence, the dry cake production rate increases with the speed of rotation (eq. 10) and the limiting factor is usually the minimum cake thickness which can stiU be successfiiUy discharged by the method used in the filter. Equation 11 shows the dependence of the sohds yield on cake thickness ... 

HCN is detoxified to thiocyanate (SCN ) by the mitochondrial enzyme rhodanese rhodanese catalyzes the transfer of sulfur from thiosulfate to cyanide to yield thiocyanate, which is relatively nontoxic (Smith 1996). The rate of detoxification of HCN in humans is about 1 pg/kg/min (Schulz 1984) or 4.2 mg/h, which, the author states, is considerably slower than in small rodents. This information resulted from reports of the therapeutic use of sodium nitroprusside to control hypertension. Rhodanese is present in the liver and skeletal muscle of mammalian species as well as in the nasal epithelium. The mitochondria of the nasal and olfactory mucosa of the rat contain nearly seven times as much rhodanese as the liver (Dahl 1989). The enzyme rhodanese is present to a large excess in the human body relative to its substrates (Schulz 1984). This enzyme demonstrates zero-order kinetics, and the limiting factor in the detoxification of HCN is thiosulphate. However, other sulfur-containing substrates, such as cystine and cysteine, can also serve as sulfur donors. Other enzymes, such as 3-mercapto-pyruvate sulfur transferase, can convert... 

Lesquerella oil is a lesser known, naturally hydroxylated seed oil that is derived from the genus Lesquerella. Of many different wild species, Lesquerella fendleri is currently the only species being developed for commercial evaluation [69]. The plant is native to the southwestern USA, and is typical in mildly alkaline, arid soils. Some attempts to investigate the adaptation of L. fendleri [70-72] to a wider enviromnent have indicated that the plant is not widely adaptable. Low adaptability, combined with difficult oil recovery and moderate acreage yield of the oil may be limiting factors in the broad commercial development of lesquerella oil. 

The steps described above at least triple yields that were previously reported r particular the yield of the second step is improved significantly. No chromatography is required for purification and all reactions can be carried out on a larger scale, the only limiting factor being the scale of the laboratory equipment. Of advantage is the use of water as solvent in all three steps. 

NOTE 1 In general the criteria in 5.3.3 result in deflection (strain) being the determining consideration in the design of pump casings. Ultimate tensile or yield strength is seldom the limiting factor. 

In many in vitro studies the acylation of the sn-3 position appears to be the rate-limiting step in TG synthesis. It has been suggested that the intracellular concentration of medium chain fatty acids may limit the final acylation reaction in TG synthesis (Dimmena and Emery 1981). Another theory is that the concentration of phosphatidate phosphatase, the enzyme that hydrolyzes the phosphate bond in phospha-tidic acid, yielding DG, may be the limiting factor (Moore and Christie 1978). The DG acyltransferase responsible for the final acylation of milk TG has been studied in mammary tissue from lactating rats (Lin et al. 1976). It was observed to be specific for the sn-1,2 DG, with very little activity observed with the sn-1,3 or sn-2,3 DG. It exhibited a broad specificity for acyl donors. The acyl-CoA specificity was not affected by the type of 1,2 DG acceptor offered, which implies that the type of fatty acid introduced into the glycerol backbone was not influenced by the specificity of subsequent acylation steps. However, the concentration of acyl donors will affect the final acylation. It was ob-... 

---