Upton to Quit NCI     

Broad WJ 《Science (New York, N.Y.)》1979,206(4425):1385

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Science and the politics of development     

Carey WD 《Science (New York, N.Y.)》1979,205(4413):1339

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Measurement of fluctuating magnetic gradients originating from oceanic internal waves     

Podney W  Sager R 《Science (New York, N.Y.)》1979,205(4413):1381-1382

Fluctuating magnetic gradients over oceans come from electric currents flowing in seawater arising from its motions across the earth's magnetic field. Gradients of 0.3 to 0.6 picoteslas per meter for each meter of internal wave displacement have been measured at frequencies of 2 to 5 millihertz with a superconductive magnetic gradiometer supported 7 meters above the surface of water 18 meters deep about 1.5 kilometers offshore from San Diego, California.  相似文献   

Extraction and analysis of organic cations from Acid solution with strong electric fields and mass spectrometry     

Ligon WV 《Science (New York, N.Y.)》1979,204(4389):198-200

High electric fields have been used to extract organic cations from solutions of small organic molecules in polyphosphoric acid. The cations have been analyzed by mass spectrometry. Production of ions by this method is shown to be related to ease of protonation by acid rather than to ionization potential.  相似文献   

Dollar-a-Gallon Gas Fuels Metric Conversion     

Broad WJ 《Science (New York, N.Y.)》1979,205(4411):1113

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The dead sea is alive and, well..     

Maugh TH 《Science (New York, N.Y.)》1979,205(4402):178

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Energy R & d fueled by few countries     

Broad WJ 《Science (New York, N.Y.)》1979,206(4425):1384-1385

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Nuclear physics     

McVoy KW 《Science (New York, N.Y.)》1979,205(4405):486-487

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Effect of different patterns of food restriction from different ages on growth and efficiency of broilers     

W. J. Yule  D. E. Fuelling 《British poultry science》1979,20(3):273-279

1. The effect of restricted feeding on performance and carcass characteristics of broilers was determined in three experiments.

2. In the first experiment, removal of food for 8 h/d from 42 to 56 d of age significantly improved food conversion efficiency of broilers on deep litter. Removal of food for 16 h/d or on alternate days tended to cause slower growth and also improved conversion efficiency.

3. In the second experiment, denial of food for 8 h/d did not significantly affect either growth rate or conversion efficiency of caged broilers. Denial of food on alternate days, from 28 d of age, depressed food intake and growth rate. Food restriction decreased dressing percentage regardless of the age of introduction. With 32, 40 or 48 h food denial each 72 h there was a large depression in growth rate and dressing percentage. Carcass dry matter was also less, indicating less carcass fat, when food was denied for 48 h each 72 h.

4. In the third experiment, growth rate of broilers on deep litter was significantly improved by denying food for 8 h/d from 28 d of age, and was significantly depressed by food denial on alternate days. This depression was significantly more severe if restriction started at 28 d rather than at 42 d of age. Conversion efficiency was not significantly improved by denial for 8 h/d.

5. In the last two experiments conversion efficiency was much worse in severe restriction.  相似文献   

Habituation by the immature fowl in response to repeated injections of corticotrophin.     

B M Freeman  A C Manning  I H Flack 《British poultry science》1979,20(4):391-399

1. Immature birds treated for 7 d with corticotrophin (30 IU/kg, one injection per day) had significantly poorer growth rates and decreased adrenal cholesterol concentrations. Plasma glucose, corticosterone and cholesterol concentrations and adrenal weight were within the normal range 24 h after the last injection.

2. The responses of birds pretreated as described above to a single injection of corticotrophin (30 IU/kg) were determined.

3. A similar degree of hyperglycaemia had developed in both groups after 2 h but thereafter the responses differed: the concentration of plasma glucose did not increase further in those pretreated with corticotrophin and had begun to decrease at 6 h, whereas that of the birds pretreated with saline increased progressively.

4. The concentrations of plasma corticosterone had increased similarly in the two groups to a peak at 2 h but there was a significantly more rapid decrease in the birds pretreated with corticotrophin.

5. Both groups showed a transient hypercholesteraemia but the increase was significant only in the group that had previously received saline.

6. There were decreases in the concentrations of adrenal cholesterol in both groups. The decrease, in absolute terms, was 2–4 times greater in the group receiving corticotrophin for the first time: percentage changes were similar, however.  相似文献