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91.
Little is known about the effect of fertilization on the N uptake of sunflowers. A 42 factorial trial with 0, 60, 120 and 180 kg N ha−1 and 0, 15, 30 and 45 kg P ha−1 was conducted over three years. The N content and concentration of leaves, stems and capitula were determined at three growth stages. High N levels increased the N content and concentration of all plant parts at all growth stages sharply. High P levels increased the N content of all plant components through better growth. P has an inconsistent effect on N concentration but tended to decrease it. After flowering the crop assimilated 20 to 25 % of the total N. This implies that N applied can still be applied and utilized by the crop at a late stage. This should be substantiated by further research.  相似文献   
92.
Night chilling (5 °C) subsequently lowered photosynthetic intensity in the leaves of maize seedlings at 20 °C through an increase in leaf diffusive resistance brought on by lower tissue water content in morning hours. A more significant increase in leaf diffusion resistance was observed when soil temperature was lowered than in the case of lower air temperature.
The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.
An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm2 of leaf area.  相似文献   
93.
Nephrogenic diabetes insipidus is characterized by polyuria, hyposthenuria and compensatory polydipsia. With conventional clinical and laboratory examinations the diagnosis can be established and the differential diagnostic diseases excluded. In order to verify the diagnosis, differentiate the condition from central and nephrogenic diabetes insipidus and rule out psychogenic polydipsia, additional laboratory studies are required: of these, the concentration test, modified Carter-Robbins test and AVP stimulation test are described.  相似文献   
94.
In a companion paper we derived the correct analysis for gerechte designs with uncorrected errors. Here we show that this correct analysis cannot be justified by the usual randomization argument. However, when the regions are rectangular there is a randomization procedure which validates an analysis with three separate error terms. We also outline other developments in design and analysis that may be more satisfactory.  相似文献   
95.
Abstract. Good land management needs information about land resources and the processes taking place in the landscape. In practical land evaluation this information is often expressed in terms of land qualities. The original survey data are stored in geographical information systems where they can be used to estimate the values of appropriate land qualities. Land qualities are complex attributes of land used in planning that may be derived from the original attributes through empirical threshold or regression models, or from process-based deterministic or stochastic simulation models. In order to improve estimates of the distribution of land qualities in space and time, and hence to improve planning decisions, the models require data with a much better spatial resolution than is usually available. The problems and dangers associated with the ad hoc linkage of simulation models and GIS are discussed. Particular attention needs to be paid to the problems of error propagation and costs and benefits when using models.  相似文献   
96.
The horses studied were of the Swiss Warmblood breed and most were ELA-typed to assess a possible association of dermal hypersensitivity to insect bites with the major histocompatibility complex. Firstly, the occurrence of the condition was examined in 304 half-siblings sired by six stallions (A to F). Fourteen cases of dermal hypersensitivity were recognized and all were in the 153 offspring of Stallions C, E and F. Most animals of this group were also investigated for chronic hypersensitivity bronchitis: none of the sires displayed clinical signs of dermal hypersensitivity, but Stallions D, E and F were affected by chronic bronchitis. Among the animals investigated for both conditions only one horse showed coincidence of the two diseases as can be expected when the diseases are not correlated. The frequency of manifest dermal hypersensitivity and/or chronic hypersensitivity bronchitis varied in the half-sibling groups of individual sires. These findings suggest that the allergic conditions are independent entities. Secondly, the occurrence of dermal hypersensitivity was studied in three generations of horses at a stud at which Stallion C had exerted a particularly strong influence. A total of 302 animals, all born and raised at this stud, were surveyed over a period of 12 years. The descendants of Stallion C showed a significantly higher incidence (P less than 0.01) of dermal hypersensitivity (two daughters out of 19; eight second generation offspring out of 103; one third generation offspring out of 85) than did the controls of the same age classes but unrelated to Stallion C at the same stud (0 out of 95).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
97.
Plasma triglyceride concentrations were measured in sheep given Intralipid or propofol, which is carried in a vehicle very similar to 10% Intralipid. A bolus dose was administered followed immediately by an infusion of the same agent for 2 h. In the animals that received propofol, the measured concentration increased by a mean amount of 3.39 mmol/l when the infusion rate was l ml/min (Group Pl) and by 7.13 mmol/l when it was 2 ml/min (Group P2). When 10% Intralipid was administered and infused at 1 ml/min (Group I10), the measured concentration increased only by 0.95 mmol/l. One hour after stopping the infusion, the excess of measured concentration over baseline had decreased in the Pl and I 10 groups to 0.52 and 0.13, respectively, of the corresponding maximum excess. The method adopted for measuring plasma triglycerides is widely used in hospitals; however, an incidental observation revealed that it is inappropriate in the presence of injections of propofol or Intralipid. Despite this, evidence and argument are presented to support the conclusion that, with propofol, plasma triglyceride concentrations increased more rapidly during the infusions and returned to baseline more slowly than with a corresponding amount of Intralipid.  相似文献   
98.
Root development of sugar beet plants on a sandy loess site with regard to nitrogen nutrition.
Root development of sugar beet plants in a sandy loess soil (Haplic Phaeozem) was observed from the early seedling stage up to harvest by measuring at first the greatest vertical and lateral extension of the root systems of single plants and later the rooting density of the whole plant stands (auger method, profile wall method).
During the seedling stage not only the subsoil, but also large parts of the topsoil between the plants remained unoccupied by the root systems. In this phase the greatest lateral extension of single roots reaches nearly the length of the greatest leaf of the plant. With the closure of the canopy the rooting density in the topsoil accounts to 1–2 cm cm−3.
In summer roots penetrate to a depth of 100–150 cm with rooting densities of 0.1 to 1 cm - cm−3. Thus, the plants gain not only access to water reserves, but sometimes meet remarkable amounts of nitrate which under the relatively dry conditions of the region tends to accumulate in 60–120 cm depth and – when taken up by the beet plants in the late stage of growth – affects crop quality negatively.  相似文献   
99.
The productivity and well-being of animals can be substantially affected by stress. This is particularly true in the case of beef calves that are subjected to a multitude of stressors over a short period during the first year of life. Perhaps the most often studied stress-responsive variable has been blood corticosteroid concentrations. Factors such as age, gender, genetics, and degree of prior experience, can influence how an animal perceives and responds to a given stressor. Few studies have tried to control these variables, and accordingly, many conflicting results have been published regarding the impact of various stressors on cortisol response. We measured baseline plasma cortisol concentration over a 44-day study in Bos indicus and Bos taurus calves. Plasma cortisol values in Bos indicus calves were higher (32.60 +/- 0.66 ng/ml) than values in calves of Bos taurus (25.81 +/- 0.76) breeding. A precipitous decrease in cortisol concentration was observed 7 days after transport stress in all calves. Baseline cortisol concentration did not provide any indication of the intensity of the various stressors. However, significant differences were readily observed after ACTH administration. On the basis of cortisol secretion, stresses of transport and weaning were similar and were the most stressful to calves, regardless of genotype.  相似文献   
100.
Twenty-five dogs with malignant lymphoma refractory to chemotherapy were treated with actinomycin D at a median dose of 0.7 mg/m2 (range, 0.5 to 0.9 mg/m2) every 3 weeks. The dogs treated had received between 2 and 8 chemotherapeutic agents (median 7), for a median of 266 days before being treated with actinomycin D. For 23 of the 25 dogs, previous chemotherapy included doxorubicin. No dog responded to actinomycin D chemotherapy.  相似文献   
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