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3.
1. Open pores were a notable feature of the shell of hens' eggs which were naturally devoid of cuticle. 2. In contrast with normal eggs, the surface of the cuticle‐less shell was irregularly contoured and, in many instances, deeply fissured. 相似文献
4.
Even though occidental food production and control systems guarantee a reasonable level of safety for consumers, western countries are facing a growing phenomenon of immigration from all over the world. With this enrichment and the shuffling of cultures and customs in the same places, even alimentary habits undergo an unavoidable evolution, also influencing the commercial trends of society. The growing demand for ethnic products, often of uncertain provenance, composition and manufacturing, has motivated the appearance of illegal trade and markets or improper local productions besides the legal ones, implying a rise in hygienic risks for the consumers. These underground realities, together with the unfilled gap that still exists between different cultures and customs cause significant difficulties in carrying out efficient controls to guarantee sanitary safety for consumers. For this reason, the risks associated with this increasing globalization must be faced with proper information and a decisive formative strategy must be divided, in order to allow the operator of the whole system and control employees to be acquainted about different raw materials, manufacturing systems, alimentary habits, languages for communication and commercial dynamics which stand beyond the new alimentary trends. 相似文献
5.
1. The effects of egg turning upon the formation of sub‐embryonic fluid (SEF), and albumen weight and composition are described up to day 8 of incubation. 2. The density of albumen increased, and the density of yolk sac contents decreased, during the first 5 d of incubation. Failure to turn eggs diminished these changes. 3. The rate of formation of SEF and its maximum weight were lower if eggs were not turned, as was the rate of decrease in albumen weight. 4. The concentration of sodium and chloride, as well as osmolality, were higher in SEF than in thin albumen, and were affected by a failure to turn eggs. 5. Static incubation altered the concentrations of yolk nutrients in SEF. 6. It is concluded that the formation of SEF is primarily dependent upon the transfer of sodium and chloride from albumen to SEF so creating an osmotic force for water movement in the same direction. Turning the eggs promotes this process by ensuring an adequate supply of ions in thin albumen adjacent to the blastoderm. 相似文献
9.
Abstract Two formulations of tebuthiuron i.e. Graslan 20P and Graslan 40P are currently being evaluated in the Molopo area. Tebuthiuron was applied aerially at ten application rates, in combination with two application dates. After only two seasons, the chemical has already shown a reasonable selectivity for the woody species. Of these, Acacia mellifera, A. reficiens and Grewia flava are very sensitive while A. erioloba and Dichrostachys cinérea are less sensitive and Boscia albitrunca seems almost resistant to the lower application rates (<1,0 kg a.i./ha). The standing crop of grass on the treated plots increased by between 220 and 740 per cent. Changes in the total grass density and botanical composition can be ascribed to an increased density of Eragrostis lehmanniana. At this stage of the trial, its selectivity in favour of the more desirable woody species, suggests that tebuthiuron shows great promise for controlling bush encroachment in the Northern Cape, although a final conclusion would only be possible 5 years after its application. 相似文献
13.
Blowfly strike and the methods used to combat blowfly strike were recorded on 33 properties in the R?ens area of South Africa during 2003/2004. Data were recorded on Merino and Dohne Merino hoggets (n = 4951) with at least 3 months' wool growth. The following data were captured: presence or absence of strike, site of the strike (body or breech), presence or absence of dermatophilosis as well as subjective scores for wool quality and wool colour. Control measures recorded include: chemical treatment (preventative and spot treatment), crutching, mulesing and the use of the Lucitrap system. Blowfly strike was not significantly influenced by gender or breed. Hoggets suffering from dermatophilosis were more likely to be struck, compared with contemporaries not suffering from the skin disorder (0.057 vs 0.027; P < 0.05). Merino hoggets generally had higher scores than their Dohne Merino contemporaries for wool quality (32.6 vs 27.4; P < 0.05) and wool colour (29.0 vs 27.2; P < 0.05). There was an indication that the Lucitrap system may have reduced flystrike, but the effect was not statistically significant (P = 0.19 for overall strikes and P = 0.12 for body strike). The Mules operation benefited overall flystrike (0.013 vs 0.110; P < 0.05); mainly through an effect on breech strike (0.010 vs 0.109; P < 0.05). The proportion of fly strikes increased with wool length, and declined with an increase in farm size in wool colour score. None of the ethically acceptable control measures assessed could substantially reduce blowfly strike on their own, and an integrated pest management programme was proposed. 相似文献
15.
1. An investigation was conducted among the progeny from crosses between Gold‐Laced Wyandotte and Double‐Laced Barnevelder bantams into the genotype of the plumage pattern of the latter. 2. The double‐laced phenotype has been shown to depend upon homozygosity of the linkage of a eumelanin intensifier melanotic Ml with a pattern gene Pg in the presence of either wheaten eWh or brown eb alleles at the E‐locus. 3. Examination of the female F2 generation demonstrated that the plumage pattern phenotype of the Double‐Laced Barnevelder depended upon homozygosity of eb(Ml‐Pg). 相似文献
16.
1. Embryos of the domestic fowl have been partially sterilised by injecting the drug busulphan into 24‐h incubated eggs. 2. Some of these embryos were injected with primordial germ cells (PGCs) after 55 h of incubation to attempt to repopulate the gonads. 3. Primordial germ cells transfected with a defective retrovirus containing the reporter gene lac Z were shown to settle in these sterilised gonads. 4. Quantitative histology of 6‐d embryos showed that busulphan produced 75% sterilisation but that PGCs could repopulate these gonads. 5. The technique of producing such germ line chimaeras is of value in studying cell kinetics, gonad differentiation and the production of transgenics. 相似文献
18.
In this study,an alpine grassland in Henan County,Qinghai Province,in the source region of the Yellow River,was selected as the study area. The shear strength of root-soil composite system characteristics of 6 different plant combination types of grassland were explored by field investigation and sampling and indoor tests,which aimed to provide a theoretical basis for preventing and controlling soil erosion and shallow landslide caused by grassland degradation. The test results showed that the shear strength of root-soil composite system of 6 different combinations was a increasing trend with the decrease of altitude. Namely,the shear strength of the root-soil composite system of Stipa purpurea Griseb. + Kobresia pygmaea C. B. Clarke at the top of the sunny slope was 27.76 kPa and the value of Elymus nutans Griseb. at the bottom of the sunny slope was 37.53 kPa. The reasons why the shear strength of 6 kinds of combinations varied from large to small with the decrease of altitude were related to their density,moisture content,root content and dry weight of roots in the root-soil composite system samples. That is,the root content of composite system at the top,middle and bottom of the sunny slope were 6.2%,5.5% and 16.2%,respectively. The values at the top,middle and bottom of the shady slope were 8.0%,11.4% and 31.6%,respectively. © 2019 China Agricultural University. All rights reserved. 相似文献
19.
1. Using a modification of the method of New (1955) explanted blastoderms of the Japanese quail were cultured for up to 72 h, and the role of ions in the formation of sub‐embryonic fluid (SEF) investigated. 2. Culture media deficient in either sodium or chloride ions reduced the volume of SEF secreted by up to a quarter. Ionic composition of the fluid was little altered, and sodium was transported against a concentration gradient. 3. Amiloride, an inhibitor of Na+/H+ exchange, reduced SEF production by half, whereas ionic composition and osmolality of the fluid was unchanged. 4. Likewise, acetazolamide, an inhibitor of carbonic anhydrase, reduced SEF production by the blastoderm, and left the ionic composition and osmolality of the fluid unaltered. 5. Neither furosemide or 4,4´‐diisothiocyanatostilbene‐2,2´‐disulfonic acid at the concentrations used changed the volume of SEF formed or its ionic composition. 6. It is concluded that the secretion of SEF is dependent upon the active transport of sodium across the blastoderm; an amiloride‐sensitive Na+/H+ exchanger and carbon dioxide hydration catalysed by carbonic anhydrase are also involved. 7. Furthermore, it is proposed that fluid transport across the blastoderm is the result of local osmotic gradients, not from a sub‐embryonic fluid hyperosmotic to albumen, as has been suggested previously. 相似文献
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