CP Symmetry Violation: The Search for Its Origin     

Cronin JW 《Science (New York, N.Y.)》1981,212(4500):1221-1228

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Science education: rhetoric and reality     

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

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Hales's Activities     

Home RW 《Science (New York, N.Y.)》1981,211(4479):271-272

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Filter measurements of stratospheric sulfate and chloride in the eruption plume of mount st. Helens     

Gandrud BW  Lazrus AL 《Science (New York, N.Y.)》1981,211(4484):826-827

Five flights of the U-2 aircraft with a filter sampler aboard were flown in the Mount St. Helens debris from 19 May to 17 June 1980. Sulfate concentrations as large as 216 times the expected background were observed. The enhancements of acid chloride vapor were considerably smaller, suggesting an insignificant increase of background values of hydrogen chloride once the plume is well mixed throughout the lower stratosphere.  相似文献   

Budget cutters clip away at science     

Broad WJ 《Science (New York, N.Y.)》1981,211(4484):799

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Science subcommittees get new chairmen     

Broad WJ 《Science (New York, N.Y.)》1981,211(4484):798-799

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Teletext war comes into focus     

Broad WJ 《Science (New York, N.Y.)》1981,211(4486):1021

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The effects of vitamin a deficiency on oral gustatory behaviour in chicks     

M. J. Gentle  W. A. Dewar 《British poultry science》1981,22(3):275-279

1. Two groups of chicks (Gallus domesticus) were fed on a vitamin A‐deficient diet for 24 d. Birds in one group, which acted as a control, were dosed orally with retinyl palmitate in corn oil, whereas the other group (experimental) was given corn oil only throughout the experiment.

2. At regular intervals birds in both groups were stimulated orally with solutions of acetic acid, quinine hydrochloride and sodium chloride and the number of beak and tongue movements counted.

3. By the end of the experiment the vitamin A‐deficient birds showed a significant decrease in their response to the oral stimulants compared with the control birds.  相似文献   

Concentrations of plasma luteinising hormone,prolactin, progesterone and androgens during the ovulatory cycle of the Turkey     

P. J. Sharp  R. W. Lea  A. Chadwick  P. E. Lake 《British poultry science》1981,22(4):375-383

1. Changes in the concentrations of plasma luteinising hormone (LH), prolactin, androgen and progesterone were measured during the ovulatory cycle of the turkey.

2. Single pre‐ovulatory peaks of plasma LH, androgen and progesterone were observed which took 8, 8 and 12 h respectively, to increase and return to base‐line values. The concentration of plasma prolactin tended to be elevated between 6 h before and 6 h after the LH peak with the maximum values occurring after the peak.

3. The changes in the concentrations of plasma LH and progesterone were 3‐ and 7‐fold respectively while 2‐fold changes were observed in the concentrations of plasma androgen and prolactin.

4. The pre‐ovulatory concentration of plasma progesterone and prolactin began to decrease 4 and 6 h respectively, after the pre‐ovulatory peak of LH.

5. Ovulation and oviposition occurred 6 to 8 h and 36.10+ 0.57 h (SEM) ( n= 11) respectively after the pre‐ovulatory peak of LH.

6. In birds kept on 14 h light/d, pre‐ovulatory peaks of LH were initiated only during a 10 to 11‐h period starting within 2 h after the onset of darkness.

7. A comparison between these data and those from the fowl suggest that the egg is retained in the turkey's oviduct for about 3 to 4 h longer than in the fowl.  相似文献   

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