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991.
1. Female broiler chicks reared in a 12‐h photoperiod which included a simulated “dawn” and “dusk” grew slightly faster than those reared in a 12‐h photoperiod of uniform light and others kept in continuous light.

2. This was apparently because the chicks subjected to dawn and dusk ate more food than those subjected to 12‐h uniform light and converted food more efficiently than those in continuous light.  相似文献   

992.
Cytogenetic and histological studies were carried out on an intersex horse which was diagnosed clinically as a cryptorchid. Surgery confirmed the horse to be a bilateral abdominal cryptorchid and histological examination revealed ovarian tissue associated with the left epididymis. Chromosome analysis of cultured cells from testicular tissue, ovarian tissue and skin revealed 64-XX and 64-XY make-up, the left gonad containing a greater preponderance of XX cells over XY cells. The external characteristics and behaviour of the horse were indistinguishable from that of a "routine" cryptorchid. Other cases of equine intersexes are reviewed and theories for the discrepancies between genetic, gonadal and phenotypic sex are discussed.  相似文献   
993.
The causative agent of stomatitis pneumoenteritis complex was isolated in domesticated goats and Vero cell culture. It was identified immunologically and morphologically as identical with the "Peste des Petits Ruminants" virus. There were cross reactions between stomatitis pneumoenteritis complex virus isolate and rinderpest virus by immunodiffusion and complement fixation tests but no cross neutralization. Goats recovered from stomatitis pneumoenteritis complex were protected against a challenge with rinderpest virus that was lethal to control goats. Ultrastructural morphology revealed intracytoplasmic and intranuclear inclusions made up of random arrays of fibrillar strands. Pleomorphic particles budded from the plasma membrane of infected cells and enveloped virions were seen extracellularly. Specific ferritin tagging was demonstrated in the stomatitis pneumoenteritis complex virus infected cells treated with homologous and peste des petits ruminants viral antibody systems but little, if any, tagging in the heterologous rinderpest system.  相似文献   
994.
Two experimental groups and series were compared (leghorns and broilers as well as two age groups of broilers) for their adaptive responses to repeated noise application. The noise was 100 dB and applied daily 30 minutes. The reference for comparison was the plasma-11-hydroxycorticosteroid concentration (11-OHKS). The results differed somewhat from those obtained earlier from one first short-time noise application, in that the rise in plasma glucocorticosteroid concentrations dropped from 431 to 210 per cent of the initial values in adult leghorns exposed to repeated noise stress over seven days. Adult broilers, however, did not exhibit any difference in the magnitude of rise of 11-OHKS concentrations by comparison between first and seven days of repeated stress. The initial values, however, were reached earlier by repeated noise application.  相似文献   
995.
Fifty six 1,2,3-benzothiadiazoles and related compounds were evaluated as carbaryl synergists against the house fly (Musca domestica). Many of these were excellent synergists, the most active being those containing various combinations of halogen, alkyl, or alkoxy substituents in the 5- and/or 6-positions of the ring.Regression analysis on the data from 14 compounds for which substituents constants were available established that synergistic activity can be satisfactorily described by equations in terms of the hydrophobic bonding constant (π) and the homolytic free radical constant (σ ·).The results with compounds related to the 1,2,3-benzothiadiazoles suggest that synergistic activity is associated primarily with the diazosulfide moiety.  相似文献   
996.
Bacillary rickettsia-like organisms (BRLO) were found in the tick Dermacentor marginatus. They are gram-negative and differ from common bacteria and reckettsiae both in the cultivation conditions and morphology. BRLO are non-pathogenic for ticks and guinea pigs. In our studies they were isolated on half-engorged females of D. marginatus, on which they are still maintained.  相似文献   
997.
998.
999.
A series of synthetic germination stimulants for the plant parasites Striga and Orobanche has been prepared. These compounds, analogues of the natural Striga germination stimulant, strigol (I), (Cook et al., 1966, 1972) cause signiticant germination of Striga hermonthica (Del.) Benth. seed at concentrations as low as 10?9 M, and an even greater activity against species of Orobanche has been demonstrated. Initial outdoor box trials of the compounds against Striga asiatica (L.) O. Ktze. in Hyderabad, India, have shown a reduction of up to 65% of the seed after a single treatment of the soil 6 weeks before the planting of the sorghum host.  相似文献   
1000.
A very low virus level was found for a short time in the blood of ducklings and goslings after experimental Lednice (Yaba 1) virus infection by subcutaneous (scut) and intranasal (inas) route and in blood of ducklings also after infection by intracerebral (icer) route. Subsequently virus neutralizing antibody formation was examined. Antibody formation was found in most of animals. In goslings onset of antibody formation seems to be slower than in ducklings after the same virus infection dose; vice versa, in ducklings antibody titer decreased after 6 weeks. Using low infection virus dose, neutralizing antibody level in ducklings was lower than in the former case. On examining the blood and the organs, the virus was detected in a very low amount and for a very short time in blood and spleen of goslings and only in blood of ducklings.  相似文献   
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