Surgeons observed     

Wilson RN 《Science (New York, N.Y.)》1979,206(4421):923-924

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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   

Vapor phase explosions: elementary detonations?     

Fowles GR 《Science (New York, N.Y.)》1979,204(4389):168-169

Although liquid-vapor explosions are widely observed, there is no established explanation for their initiation and propagation. Thermodynamics admits the possibility that superheated liquids can support detonations analogous to those that occur in chemical explosives. For liquid methane superheated 50 K above its boiling point at 1 atmosphere, the energy of explosion is 2 to 3 percent of that of TNT.  相似文献   

Marine life histories     

Scheltema RS 《Science (New York, N.Y.)》1979,205(4402):181-182

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Metal chelate compounds     

Sievers RE 《Science (New York, N.Y.)》1979,205(4412):1255-1256

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Global pollution: is the arctic haze actually industrial smog?     

Kerr RA 《Science (New York, N.Y.)》1979,205(4403):290-293

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Rapeseed meal and egg taint: Treatment of rapeseed meal to reduce tainting potential     

G. R. Fenwick  A. Hobson‐Frohock  D. G. Land  R.F. Curtis 《British poultry science》1979,20(3):323-329

1. Treatment of rapeseed meal with calcium hydroxide suspension decreased the sinapine content by up to 90%. Smaller decreases were obtained by autolysis, steaming and treatment with ammonia.

2. When this treated meal was fed to susceptible ("tainting") hens the concentration of trimethylamine in the eggs was decreased to much less than that required to cause taint.  相似文献   

Effect of light,vitamin d and dietary phosphorus on egg‐shell quality late in the pullet laying year     

A. L. Yannakopoulos  T. R. Morris 《British poultry science》1979,20(3):337-342

1. Eighteen diets supplying all combinations of three phosphorus contents (3.1, 4.0 and 4.8 g non‐phytate P/kg) and six vitamin D supplements (37.5 or 150 μg cholecalciferol/kg; or 16 or 24 μg 25‐hydroxy‐cholecalciferol/kg; or 37.5 μg cholecalciferol/kg with either 16 or 24 μg 25‐hydroxycholecalciferol/kg) were fed to 2 880 pullets of two stocks from 64 to 74 weeks of age. The birds were housed in eight light‐proof rooms, four of which had 24‐h light‐dark cycles (16L : 8D) and four had 28‐h cycles (20L : 8D).

2. The dietary treatments had no significant effect upon food intake, egg output, shell thickness, shell deformation or specific gravity of the eggs.

3. The 28‐h cycle reduced mean rate of lay by 4.5%, increased egg weight by 5.8% and increased shell thickness by 9.4%. The proportion of eggs with shell faults revealed on candling was reduced from 4.1 % to 2.8%.

4. It is concluded from this and other sources that decreasing dietary phosphorus or modifying vitamin D supplements may sometimes lead to increases in shell thickness of the order of 1 to 2%, but that these changes are unlikely to result in a measurable reduction in the proportion of cracked eggs late in the laying year.

5. A 28‐h light‐dark cycle results in a longer and more uniform interval between consecutive ovipositions and thus gives reliable increases in shell thickness which are large enough to reduce the proportion of cracked eggs in many practical situations. Whether it is profitable to use an ahemeral cycle will depend upon the relative prices paid for eggs of different sizes.  相似文献   

Comparison of maize,wheat and triticale in broiler diets     

N. V. Reddy  D. R. Rao  G. R. Sunki 《British poultry science》1979,20(4):357-362

1. Wheat, triticale 131 or triticale 72‐S could replace up to half the maize in broiler diets without affecting performance. Replacing more of the maize on either an equal nitrogen basis or a weight basis adversely affected performance.

2. Triticale 72‐S appeared to be superior to triticale 131 as a direct replacement for maize, but both grains were inferior to maize as energy sources.  相似文献   

A diet formulated from by‐products and indigenous foodstuffs for laying hens     

Jean Allen  R. B. N. King  J. J. Holmes 《British poultry science》1979,20(4):363-370

1. The performance of six commercial stocks of laying hens fed on a diet composed of home‐produced foodstuffs, not usually used for human consumption, was compared with that of birds fed on a conventional diet.

2. The experimental diet was calculated to be low in energy and methionine and high in fibre by conventional standards. Birds ate up to 12% more of this diet, but the calculated intakes of energy and methionine were less than those of the corresponding controls.

3. White stocks fed on the experimental diet produced seven eggs less per bird than controls while the production of brown stocks was essentially unaffected.

4. The gross efficiency of energy utilisation for egg production was better with the experimental diet.  相似文献