Advances in Mutagenesis Research. Vol. 1. G. Obe, Ed. Springer-Verlag, New York, 1990. x, 217 pp., illus. $79.50     

L K 《Science (New York, N.Y.)》1990,247(4950):1594

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Takeover Bid: Chiron's Discussions with the Media     

Rutter WJ 《Science (New York, N.Y.)》1990,247(4950):1530

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Herbicides and Plant Metabolism. A. D. Dodge, Ed. Cambridge University Press, New York, 1990. x, 277 pp., illus. $65. Society for Experimental Biology Seminar Series, 38. From a seminar, York, U.K., April 1987     

L K 《Science (New York, N.Y.)》1990,248(4956):751-752

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Teaching the History of Science. Michael Shortland and Andrew Warwick, Eds. British Society for the History of Science and Basil Blackwell, New York, 1989. viii, 281 pp. $29.95. Based on a conference, Oxford, U.K., 1987     

Olesko KM 《Science (New York, N.Y.)》1990,248(4960):1242-1243

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The suitability of morphometric parameters of fat cell size for the purposes of animal science research. 1. Cellularity of swine subcutaneous adipose tissue influenced by different fattening ages and graded feed levels     

G Sturm  K Loeffler 《Berliner und Münchener tier?rztliche Wochenschrift》1990,103(3):73-81

The cellularity of subcutaneous adipose tissue of 108 male castrated pigs (German Landrace) was investigated. The tissue was taken bioptically under anesthetic conditions. The outer and the inner layer of backfat were examined separately, fresh unfixed tissue slices floating in Ringer solution were subjected to microscopic measurements of adipocyte diameters. The animals were kept in feeding experiments, 3 and 2 sectors respectively of growing period were examined (40 kg; 66 kg, 88 kg body mass) divided into 6 and 4 feeding levels respectively for 21 days (0.4; 0.6/0.8; 1.0; 1.2; 1.4 MJ metabolic energy per kg body mass0.75 per day). The inner layer of backfat showed bigger fat cells compared to the outer layer. The average fat cell size was greater for the older and heavier than for the younger animals. The gradation of food administration resulted not in a straight parallel rise in fat cell size but in an effective consequence with respect to the distribution frequency of the dates: The higher the food energy level, the more the accumulation of small fat cells from 10 til 30 microns diameter. These cell fractions succeeded in being signified as typical and important closed population. Other authors also had described these particular cells, i.e. "fat cell clusters" and "VSFC" (= very small fat cells) respectively. An external use of the dates for computer simulation programs resulted in success and manifested the independently gained conclusions. The examinations were performed by support of different branches of literature and the results had to be discussed in front of a wide background of known connections.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Ectopic ureter in the horse: Three cases and a review of the literature          下载免费PDF全文

Pringle JK  Ducharme NG  Baird JD 《The Canadian veterinary journal. La revue veterinaire canadienne》1990,31(1):26-30

Ureterovesicular anastomosis resulted in resolution of the clinical signs of urinary incontinence in three horses with unilateral ectopic ureter. Follow-up of two of the horses ten months and three years later indicated no further urinary tract problems; the third horse died four days after surgery from intestinal infarction.

Diagnosis can be readily confirmed by antegrade or retrograde ureterography, or endoscopic visualization of the ectopic ureteral openings. Nephrectomy appears indicated in cases of unilateral ectopic ureter with associated ipsilateral urinary tract infection or hydronephrosis, providing the contralateral kidney has normal function. Ureterovesicular anastomosis appears to be indicated in the management of unilateral ectopic ureters in the absence of ascending urinary tract infection or hydronephrosis, and in cases of bilateral ectopic ureters.

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Test for linkage between the eumelanin dilution blue (B1), the extended black (E) allele at the E-locus and the linked pea comb (P) and eumelanin extension (M1) genes in the domestic fowl     

W C Carefoot 《British poultry science》1990,31(3):465-472

1. A mating was made between a Blue Andalusian bantam male and a pea comb striped necked bantam female to produce a quadruple heterozygote of the linked pea comb (P) and eumelanin extension (Ml) genes and of the eunmelanin dilution blue (Bl) gene and the extended black (E) allele at the E-locus. 2. Two pea comb blue females so produced were mated to a single comb striped necked bantam male, thus providing a backcross to the quadruple recessive. 3. Bl segregated independently with each of the other three genes whilst 25 crossovers occurred amongst the 55 progeny assessed for linkage between P and Ml, confirming loose linkage between P and Ml which had previously been shown to be approximately 46 units. Linkage of 0.3% had been previously reported (Crawford, 1986) between P and a "melanotic" gene isolated from a segregating gene pool. Evidence is presented to demonstrate that two different "melanotic" genes were being considered, thus explaining the apparently contradictory reports. Charcoal (cha) is suggested for the recessive gene linked with P by 0.3%. 4. Thirty-four crossovers occurred among the 97 progeny between P and E suggesting linkage of approximately 35 units. A further mating was made from among segregants in the backcross which confirmed P-E linkage with 17 crossovers in 55 gametes. Combining the tests produced a linkage value of approximately 34 units.  相似文献   

Wildlife management          下载免费PDF全文

Jones WW 《The Canadian veterinary journal. La revue veterinaire canadienne》1990,31(6):415-416

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Calving patterns in seasonal dairy herds     

Macmillan KL  Henry RI  Taufa VK  Phillips P 《New Zealand veterinary journal》1990,38(4):151-155

Two field studies examined the calving patterns of cows in seasonal dairy herds in the Waikato (Field Study 1) and South Taranaki regions (Field Study 2). The first study examined patterns for cows commencing their second or subsequent lactation in herds which had used an inseminating service during the previous season. The second study included first lactation heifers only in 15 herds where animals had been naturally mated, and in 15 herds in which they had been synchronised and then artificially inseminated at the synchronised oestrus. The parameters describing calving patterns were based on the date for each herd's planned start of calving (PSC), which was 282 days from the date on which breeding commenced in the preceding season. The average interval from PSC to mean calving date for the 35 herds in Field Study 1 was 22 days, with individual herds ranging from 15 to 30 days. In herds with heifers which had been naturally mated (Field Study 2), it was 17.6 days compared to 11.0 days for previously synchronised animals. Calculating the intervals from PSC to median calving date and separately for the last two quartiles more effectively described a herd's calving pattern. The duration for the last quartile of the calving pattern was influenced by the extent and timing of induced calving. In Field Study 1, 88.6% of the 35 herd owners induced premature parturition in at least one cow. In these herds, 11.3% of cows were treated and calved prematurely. Only 61.7% of heifers which had previously been naturally mated calved by 3 weeks after PSC. Their calving dates were not evenly distributed over this 3-week period, with 9.8% in the first week and 25.6% in the third week. The calving pattern for heifers which had been previously synchronised showed several distinct peaks. Calvings to the synchronised mating were completed 15 days after PSC, by which time 64.7% of animals had calved. By 3 weeks after PSC, 72.9% of these heifers had calved. The results showed that there was considerable variation in calving patterns in seasonal dairy herds. This variation would have been due to differences in conception pattern, and the way induced calving had been applied. The calving pattern in heifers which had been naturally mated was less concentrated than had been expected. Synchronisation can significantly concentrate the calving pattern of these first lactation animals. The parameters used to describe calving patterns may be less applicable in herds in which a high proportion of animals is induced to calve prematurely, or where a whole herd is synchronised. Nonetheless, they do serve as an illustrative example of the variation in calving patterns among herds.  相似文献   

Taste aversion learning in horses   总被引：1，自引：0，他引：1  

K A Houpt  D M Zahorik  J A Swartzman-Andert 《Journal of animal science》1990,68(8):2340-2344

The ability of ponies to learn to avoid a relatively novel food associated with illness was tested in three situations: when illness occurred immediately after consuming a feed; when illness occurred 30 min after consuming a feed; and when illness was contingent upon eating one of three feeds offered simultaneously. Apomorphine was used to produce illness. The feeds associated with illness were corn, alfalfa pellets, sweet feed and a complete pelleted feed. The ponies learned to avoid all the fees except the complete feed when apomorphine injection immediately followed consumption of the feed. However, the ponies did not learn to avoid a feed if apomorphine was delayed 30 min after feed consumption. They could learn to avoid alfalfa pellets, but not corn, when these feeds were presented with the familiar "safe foods," oats and soybean meal. Ponies apparently are able to learn a taste aversion, but there were constraints on this learning ability. Under the conditions of this study, they did not learn to avoid a food that made them sick long after consumption of the food, and they had more difficulty learning to avoid highly palatable feeds.  相似文献