A New Route to Intermetallics: Metal silicides and related intermetallic compounds with unusual properties are formed by exposing supported metals to volatile organometallics     

Maugh TH 《Science (New York, N.Y.)》1984,225(4660):403

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Approval Near for European Synchrotron: France and Germany have reached an agreement; funding and location remain to be settled, but construction could begin next year     

Dickson D 《Science (New York, N.Y.)》1984,225(4660):391-392

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Economic geology: metal deposits in relation to plate tectonics     

Strong DF 《Science (New York, N.Y.)》1984,225(4663):708-709

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Native cellulose: a composite of two distinct crystalline forms     

Atalla RH  Vanderhart DL 《Science (New York, N.Y.)》1984,223(4633):283-285

Multiplicities in the resonances of chemically equivalent carbons, which appear in the solid-state carbon-13 nuclear magnetic resonance spectra of native celluloses, have been examined at high resolution. The patterns of variation are consistent with the existence of two distinct crystalline forms. One form is dominant in bacterial and algal celluloses, whereas the other is dominant in celluloses from higher plants.  相似文献   

Semisynthetic Enzymes Are New Catalysts: Enzymes may be the ultimate catalysts, especially if their specificities can be changed by chemical modification     

Maugh TH 《Science (New York, N.Y.)》1984,223(4632):154-156

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The laying performance of two strains of hens offered diets containing dried poultry manure during the laying stage     

D. J. W. Lee  W. Bolton 《British poultry science》1977,18(1):1-7

1. Light‐weight (Babcock B300) and medium‐weight (Warren‐SSL) hens were offered diets, containing 0, 100 or 200 g dried poultry manure (DPM) and 11.49, 11.12 or 10.83 MJ metabolisable energy/kg respectively, between 18 and 70 weeks of age. The true protein, metabolisable energy, calcium and phosphorus contents of the DPM, from caged layer hens, were used in the diet formulation.

2. The hen‐housed laying performance of hens offered the DPM‐containing diets was significantly better for number of eggs laid and total egg mass produced but the performance of the control groups was lower than would normally be expected of those stocks. The reason for the lower rate of lay and higher mortality of hens fed on the control diet was not identified. The amount of food consumed increased as the energy content of the diet decreased and the efficiency of food conversion (EFC) of the lightweight strain was reduced; there was no significant effect on the EFC of the medium‐weight hens.

3. The inclusion of DPM in the diets had no effect on albumen quality or on the incidence of hair‐cracked, cracked or broken eggs. However, with both strains of hens, shell weight and shell thickness were poorer when 100 or 200 g DPM/kg diets were fed.  相似文献   

Exencephaly in chicken‐pheasant hybrids     

V. D. Purohit  Parvathi K. Basrur  B. S. Reinhart 《British poultry science》1977,18(2):143-146

1. The incidence of exencephaly was investigated in chicken‐pheasant hybrids.

2. With the pheasant as sire, fertility was 7.lb6%, but with the fowl it was 19.lb5%; hatchability of fertile eggs, however, was similar, 42% and 41% respectively.

3. Only one exencephalic hybrid was obtained when the sire was the pheasant but 70 were noted when the fowl was sire. The incidence of this malformation in hatched chicks was 12 times more in crosses with the fowl as sire than in the reverse cross.

4. The frequency of exencephaly was greater with Rhode Island Red, Barred Leghorn or White Leghorn roosters than with Columbian Rock roosters.  相似文献   

Views defended by debater          下载免费PDF全文

Hulland TJ 《The Canadian veterinary journal. La revue veterinaire canadienne》1977,18(7):200

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The hen's egg: Relationship of mean strain energy at shell fracture to shell compression speed,the nature of the compressing body and the location on the shell of the point of contact     

T. C. Carter 《British poultry science》1977,18(2):205-211

1. The mean energy, E_f, required for fracture of an egg shell at its equator by a flat plate is known to depend on shell compression speed, v_m, for speeds in the range 20 μm/s to 2.lb5 mm/s; analysis of published data shows that E_f bears a linear relationship to log (v_m ) throughout the industrially important speed range from 20 μm/s to 1.lb1 m/s, increasing from 1.lb3 to 5.lb0 mJ.

2. At lower speeds down to 2 μm/s E_f is constant.

3. E_f is reduced if the flat plate is replaced by a sphere or cylinder; the greater its curvature, the smaller E_f.

4. E_f for the narrow pole is greater and for the broad pole smaller than that for the equator but these differences may be due in part to . systematic differences in shell thickness as well as curvature.  相似文献   

Life below the ross ice shelf, antarctica     

Lipps JH  Ronan TE  Delaca TE 《Science (New York, N.Y.)》1979,203(4379):447-449

Samples and observations under 420 meters of ice and 430 kilometers from the open sea on the Ross Ice Shelf at a water depth of 597 meters revealed an unusual assemblage of benthic organisms. Scavenging amphipods, an isopod, and fish were present but a living infauna was absent. The observations may be accounted for by sampling or spatial bias, or by extremely low or fluctuating trophic resources.  相似文献