The use of air‐coolers in broiler houses under subtropical conditions in Iraq

1. Under summer conditions in north Iraq, 2 000 chicks were reared for 56 d in two broiler houses. One house was provided with two air‐coolers. The birds were housed at densities of eight to 16 birds/m².

2. Differences in weight gain between birds in cooled and uncooled houses ranged from 101.5 g at eight birds/m² to 385 g at 16 birds/m². Food consumption increased gradually with increasing bird density. Food conversion efficiency, meat yield and carcass conformation were much better in the cooled house than under conventional conditions.

3. The financial return/m² ranged from 2.30 to 4.51 ID¹ in the cooled house, compared with 2.01 to 2.77 ID in the uncooled house at different floor densities.     

新疆阿尔泰山两河源国家级自然保护区树附生地衣群落物种分布与环境关系的研究

为了查明阿尔泰山两河源国家级自然保护区树附生地衣物种组成成分,以及探讨影响该地区树附生地衣群落分布格局与环境因素之间的关系,以附生地衣覆盖度为指标,应用除趋势对应分析(DCA)对样点进行分组,运用典范对应分析(CCA)分析附生地衣分布与环境因素的关系,结果表明:1)阿尔泰山两河源自然保护区树附生地衣共有49种隶属于15科30属。2)根据DCA分析将该地区树附生地衣划分为3个样点组,样点组1共有地衣22种,总盖度为2.639%,物种多样性指数为1.603;样点组2共有地衣27种,地衣总盖度为3.717%,物种多样性最大为1.972;样点组3:共有地衣12种,地衣总覆盖度为1.036%,物种多样性最小量为0.871。3)CCA排序结果表明:低海拔区,人为干扰强度高,地衣多样性较低;中海拔区,森林郁闭度高,湿度适中,干扰较少,地衣多样性较高;高海拔区,森林郁闭度较低,树种较少,光强度较强,干扰较少,主要以壳状地衣为主,多样性较低。     

Relative Prevalence of Antibiotic Resistance among Heterotrophic Bacteria from Natural and Culture Environments of Freshwater Prawn,Macrobrachium Rosenbergii

As antibiotic residues and multidrug‐resistant (MDR) bacteria are of increasing concern to those involved in the seafood industry, there is an intense international focus to monitor MDR bacteria in seafood. There is also a trend to source seafood from organically raised farms in order to reduce antibiotic usage in culture operations. Hence this study was conducted to compare the antibiotic resistance among bacteria associated with various samples from the natural and culture environment of Macrobrachium rosenbergii. Samples from the natural environment included water, sediment, eggs, larvae, postlarvae (PL), feed items, and gut samples of M. rosenbergii and those from the culture environment were water, sediment, eggs, feed pellets, and gut samples of M. rosenbergii. Bacteria from water samples of natural and culture environments were frequently resistant to ampicillin, erythromycin, and penicillin, while more than 50% of the strains from sediment were resistant to erythromycin, nalidixic acid, and penicillin. Bacterial isolates from commercial feed had a relatively high degree of antibiotic resistance. Interestingly, occurrence of multiple drug resistance was higher among the bacteria associated with the samples from the natural environment of M. rosenbergii, pointing to more favorable selection pressure for drug resistant mutants in the natural environment.     

枣实蝇对不同发育期骏枣和酸枣果实的生物学响应变化

【目的】研究枣实蝇在寄主植物果实不同发育期的危害程度对其最佳防治期。【方法】分析枣园对不同寄主枣树样枝套袋枣实蝇的蛀果率,调查虫口密度;室内饲养测定果实不同发育期对枣实蝇生长发育和繁殖的影响,分析和评价枣实蝇对不同发育期骏枣和酸枣果实的生物学响应变化。【结果】枣实蝇对骏枣果实的蛀果率均大于对酸枣的蛀果率,并且枣实蝇在骏枣果实成熟期蛀果率为最大;成熟期骏枣上的虫口密度也最大;骏枣上雌虫产卵痕数、幼虫数和卵的孵化率均大于酸枣上的枣实蝇。在枣果着色期和成熟期,蛹的各项生长指标均高于膨大期;果实不同发育期,骏枣上的蛹各项生长指标均显著大于(P<0.05)酸枣上的;骏枣上枣实蝇的蛹期、雌虫怀卵量、性成熟历期、交配时间以及雌雄成虫寿命均略大于酸枣,但无显著差异(P>0.05)。【结论】枣实蝇对骏枣的选择性强于酸枣,并且成熟期的骏枣果实更适宜枣实蝇生长发育。     

托木尔峰自然保护区地衣的补充研究

我们根据多年的研究并结合前人的工作进一步地整理了分布在新疆托木尔峰自然保护区的地衣种类。分析该地区的地衣种有１２０个，分别隶性于４９属，其中有１１个变种和４个变型。调查中我们还发现该地区地衣随着海拔高度的升高而有所不同，北坡和南坡也有明显的差异。     

Palygorskitreicher Vertisol im ariden Bereich NO-Somalias

Palygorskite rich Vertisol in the arid part of NE-Somalia In the arid part of NE-Somalia on a large plane in the central part of the Darror Valley Vertisols rich in palygorskite are found. The investigated Vertisol is very poor on smectite and vermiculite. The parent material of the soil consists of Pleistocenic fluvial sediment, which originated from Tertiary stones. In the field, slicken sides in 92 to 140 cm depth and cracks reaching a depth of 100 cm were observed in the soil. The cracks were partly filled with topsoil material. Because of the fresh appearance of gilgai microrelief and the cracks, which are partly empty, peloturbation must be active under the present climatic conditions. The high content of palygorskite in the investigated Vertisol seems to be lithogenic and originating from Tertiary sediments found in the surrounding area.     

Effects of industrial liquid wastes on dinitrogen fixation and microflora of soils and waters

Potential N₂-fixation was investigated in a number of samples representing soils and water courses under the effect of some industrial wastes in Helwan area of Egypt. Microbiological analysis of soil and water samples showed the general enrichment of fungi, actinomycetes and bacteria including N₂-fixers. Among asymbiotic N₂-fixers, azospirilla compared to azotobacters and clostridia were found to be present with rather higher densities in all samples tested. Generally, the microbial numbers increased by increasing the distance from the Industrial Complex at Helwan, which could be attributed to the high levels of salinity and total heavy metals near the factories. The results indicated that the industrial wastes near the factories exerted inhibitory effects on the acetylenereducing activity in soils, which seriously reduces their biological fertility. Such effects were decreased by getting away from the factories. Significantly negative correlations were recorded between densities of N₂-fixers or N₂-ase activity and salinity and total heavy metals content in both soil and water samples.