Breeding-related growth of captive Sparus aurata (Teleostei,Perciformes)

Growth is arrested in male and female Sparus aurata during gonadal recrudescence and spawning. Growth and feeding rates of fish exposed to a constant long photoperiod ($\text{16L}\text{8D}$) were significantly higher than those of fish under a natural photoperiod. When the experimental photoperiod was shortened, fish underwent gonadal recrudescence and reduced feeding, and their growth was arrested. Fish under the long photoperiod regime reached the commercial weight of 350 g six months earlier than the controls.     

Quantitative Genetic Analysis of Traits in Avocado Cultivars *

This research is aimed at quantitative genetic analysis of several avocado traits and cultivars. The experimental material consists of our avocado breeding project in which data were collected from several crosses as well as selfings of cultivars. Parenthood was determined by isozymes and the seedling progenies were assessed for eight traits. A biometrical genetic approach for analysis of this breeding project is presented. Genetic profiles of the traits and cultivars were detailed by several characteristics: level of heterozygosity and dominance deviation, dominance of alleles, dominance direction, general evaluation of additive and non-additive genetic variance, maternal inheritance, and allelic differences among the various cultivars in major genes controlling the same quantitative trait. Five avocado cultivars: ‘Fuerte’, ‘Hass’, ‘Ettinger’, ‘Tova’, and ‘Rosh-Hanikra’, were characterized separately for each trait. Practical conclusions for the breeder regarding economically important quantitative traits are discussed.     

Genetic association between DNA fingerprint fragments and loci controlling agriculturally important traits in avocado (Persea americana Mill.)

Summary Associations between DNA fingerprint fragments and 16 avocado quantitative trait loci were tested for in two avocado tamilies by one way analysis of variance and multiple regression analysis. Based on these two analyses the fragments P4, P8, E2 and E5 in Pinkerton × Ettinger progeny were found to be associated with harvest duration, skin color, skin thickness and skin surface, respectively. The fragments P1, P8, B1 and B4 in the Pinkerton × Bacon progeny (half sibs of the original population) were found to be associated with fruit weight, skin color, seed size and peeling, respectively. Based on the original Pinkerton progeny as well as on the half sibs progeny, the fragment P8 was found to be associated with black-purple fruit skin color.The fragment pattern intensity of DNA pools of progeny having either green or black-purple fruit skin color —supported these data. These results are interpreted as genetic-linkage between the DNA fingerprint fragment P8 and locas (1) regulating fruit skin color in avocado.     

Modelling temperatures and salinities of mixed seawater fish ponds

Modelling of fish pond temperatures and salinities requires application of fundamental energy and mass balance equations. Temperatures and salinities can then be simulated, given the hydrological characteristics and simple weather data. Results of several temperature estimation experiments of 1 and 5 days duration are discussed. The results indicate that pond temperatures can be accurately estimated if the transfer coefficients are known. While salinity estimation is discussed, experiments were not performed, since the temperature experiment indirectly used the salinity data.     

赣江源区主要土壤抗蚀性能对比

 为了对江西省赣江源区内主要土类的抗蚀性能进行研究,测定各土类的有机质质量分数、密度、抗蚀指数、团聚度、团聚状况、分散率、分散系数、结构破坏率和水稳性团聚体含量等抗蚀性指标,进行主成分分析。结果表明,土壤的抗蚀性大小顺序为:山地矮林土(74.67)>黄壤(61.90)>山地黄红壤(47.26)>黄红壤(44.77)>紫色土(39.79)>红壤(28.34)。在红壤、紫色土区域不仅要预防以暴雨为主要侵蚀力的水土流失,而且需采取相应的措施增加地被物覆盖度、减少人为破坏,以及通过施肥等措施增加土壤的抗蚀性,从而减少水土流失;山地黄红壤、黄红壤区域必须对民众做好宣传工作,在开发利用的同时加强人们对生态环境的保护意识,避免边治理边破坏现象一再发生;黄壤和山地矮林土地区,在综合利用时注意保持现有的良好生态环境,尽可能地避免有利于水土流失活动行为的发生;土壤有机质质量分数、团聚度、团聚状况是评价赣江源自然保护区土壤抗蚀性强弱的最好指标。     

Detection and counting of flowers on apple trees for better chemical thinning decisions

Precision Agriculture - Accurate chemical thinning of apple trees requires estimation of their blooming intensity, and determination of the blooming peak date. Performing this task, as of...     

Coliforms,fecal coliforms,and fecal streptococci as indicators of water pollution

The presence and survival of coliforms, fecal coliforms, and fecal streptococci were studied in sewage treatment plants, heavily polluted rivers, a lake, and other drinking water sources. In all cases the fecal streptococci were generally more resistant to the natural water environment and to purification processes than the other indicator organisms and, at points distant from the original source of pollution were often the only indicators of the fecal nature of the pollution. In two of the systems studied the survival of the fecal streptococci paralleled the survival of enteric viruses better than the coliforms. The fecal streptococci may thus in certain cases provide a better estimate of the probable virus content in lightly contaminated water than the other two indicators.     

初配东北虎的繁殖

通过对一对初配东北虎繁殖全过程的总结，即对母虎发情行为、公母虎合笼交配、妊娠判定、产前准备、产后护理、仔虎的生长发育情况的详细观察与分析，为初配东北虎的繁殖提供了有益的借鉴。     

Selection of food items for inclusion in a newly developed food-frequency questionnaire

OBJECTIVES: To highlight the differences between the food list required in a food-frequency questionnaire (FFQ) to rank people by their intake and the food items that contribute to absolute intake, and to discuss possible applications. METHODS: We conducted a nutritional survey among 1173 adults using an adapted 24-hour recall questionnaire. STATISTICAL ANALYSIS: To develop an FFQ, we analysed the 24-hour recall survey data by performing a stepwise multiple regression after grouping conceptually similar food items into 175 food groups. RESULTS: In total, 126 food groups were included in the developed FFQ in order to explain at least 80% of the variance in the consumption of each of 27 nutrients. The nutrients that were explained by a few food groups were vitamin A (one food group), alcohol (two), beta-carotene (two), vitamin E (three) and cholesterol (five). Nutrients that were explained by a large number of food groups were energy (37 food groups), potassium (31), magnesium (31), dietary fibre (30), phosphorus (31) and sodium (29). Using energy intake as an example, soft drinks were the best between-person energy classifiers, while providing only 2.4% of the total energy intake. Wine, seeds and nuts, which contributed highly to the variance, were minor energy contributors. In contrast, milk, sugar, fried chicken/turkey breast or whole chicken/turkey, which explained little of the variation in the population, were major energy contributors. CONCLUSIONS: Developing an FFQ on the basis of common foods may not explain the between-person variation required for ranking individual intake in diet-disease studies. Producing lists of "discriminating items" can be a useful application in developing mini-FFQs for selected nutrients.