Tumor virology updated     

Livingston DM 《Science (New York, N.Y.)》1981,212(4499):1139-1140

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A regional prehistory     

Dincauze DF 《Science (New York, N.Y.)》1981,212(4499):1140-1141

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1980 report of the executive officer     

Carey WD 《Science (New York, N.Y.)》1981,211(4485):916-921

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Science education: rhetoric and reality     

Carey WD 《Science (New York, N.Y.)》1981,211(4480):339

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State of stress and intraplate earthquakes in the United States     

Zoback MD  Zoback ML 《Science (New York, N.Y.)》1981,213(4503):96-104

Recently compiled data on the state of stress have been used to define stress provinces in the conterminous United States in which the orientation and relative magnitude of the horizontal principal stresses are fairly uniform. The observed pattems of stress constrain mechanisms for generating intraplate lithospheric stresses. Coupled with new information on geologic structure and tectonism in seismically active areas of the Midcontinent and East, these data help to define some characteristics common to these areas and to identify key questions regarding why certain faults seem to be seismically active.  相似文献   

Echoes of toronto     

Bromley DA 《Science (New York, N.Y.)》1981,213(4512):1063

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A framework for systematics     

Straney DO 《Science (New York, N.Y.)》1981,214(4522):788-789

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The effect of 6‐ and 8‐hour light‐dark cycles on egg production and pattern of ovipositions     

Y. Nys  P. Mongin 《British poultry science》1981,22(4):391-397

1. Two flocks of 60 laying hens were transferred from 14 h light (L): 10 h dark (D), to repeated 3L:3Dor4L:4D lighting schedules at 37 weeks of age. Egg production decreased slightly but egg weight and shell quality improved.

2. The intake of low‐calcium diet and of oyster shell were similar for each light period of each lighting regimen.

3. Ovipositions were distributed virtually at random throughout the day and the mean interval between successive eggs within a clutch was increased.

4. Reducing the total daily photoperiod from 12 to 6 h decreased daily food consumption.  相似文献   

Some factors affecting urinary and Faecal nitrogen loss by chickens fed on a protein‐free diet     

J. Okumura  Y. Isshikp  Y. Nakahiro 《British poultry science》1981,22(1):1-7

1. In adult colostomised cockerels, the rates of urinary and faecal nitrogen loss were measured when feeding low‐ and high‐energy, protein‐free diets after a preliminary period during which diets of differing energy and protein contents had been fed.

2. Urinary nitrogen excretion increased with increasing protein and decreasing energy in the preliminary diet.

3. Urinary nitrogen excretion was high during the first 3 d of feeding a high‐energy, protein‐free diet, decreased rapidly during the next 3 d and thereafter become relatively constant. However, in the case of a low‐energy, protein‐free diet, urinary nitrogen excretion gradually declined throughout the trial period of 15 d, resulting in increased urinary nitrogen excretion.

4. After a 3‐d period of adjustment faecal nitrogen loss from birds fed on a protein‐free diet was relatively constant under the conditions examined.  相似文献   

Aspects of metabolism related to the occurrence of skin lesions in biotin‐deficient chicks     

C. C. Whitehead  D. W. Bannister 《British poultry science》1981,22(5):467-472

1. Chicks were fed on biotin‐deficient low‐ and high‐protein diets supplemented with increasing concentrations of biotin.

2. Biotin deficiency decreased hepatic activity of pyruvate carboxylase [EG 6.4.1.1] but activity of acetyl‐CoA carboxylase [EG 6.4.1.2] was comparatively unaffected.

3. Increasing dietary protein increased the severity of biotin deficiency as assessed by skin lesions and decreased plasma biotin concentrations.

4. The severity of the skin lesions over all the treatments was most closely related to plasma biotin concentration.  相似文献