The Yangtze River dolphin or baiji (Lipotes vexillifer): population status and conservation issues in the Yangtze River,China

• 1. Baiji were sighted 17 times during three recent simultaneous multi‐vessel surveys in the Yangtze River, China (November 4–10, 1997; December 4–9, 1998; October 31–November 5, 1999). There were 11 sightings in 1997 (consisting of 17 animals), five in 1998 (seven animals), and two in 1999 (four animals). It was concluded that 13 individuals could be considered as a minimum number of the baiji currently in the Yangtze River.
• 2. An annual rate of population decrease was roughly estimated as 10%. From the body sizes observed, the proportions of old, adult and immature individuals were approximately estimated at 57, 26, and 17% respectively.
• 3. Baiji showed a significant attraction to confluences and sand bars with large eddies. The present distribution range of the baiji is less than 1400 km in length in the Yangtze main river. Distances between the two nearest groups of baiji appear to be increasing.
• 4. Two typical sightings are described, in which surfacing and movements of baiji were recorded. Baiji were often found swimming together with finless porpoise. In the surveys they occurred in the same group in 63% of occurrences. Interactions between baiji and finless porpoise are described and discussed.
• 5. Human activities are the main threats to the baiji. Illegal electrical fishing accounted for 40% of known mortalities during the 1990s. Engineering explosions for maintaining navigation channels have become another main cause of baiji deaths. The last hope of saving the species may be to translocate the remaining baiji into a semi‐captive reserve, known as the ‘Baiji Semi‐natural Reserve’.

Copyright © 2003 John Wiley & Sons, Ltd.     

Reducing the potential for processing contaminant formation in cereal products

Processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, are not present or are present at much lower concentrations in the raw, unprocessed food, and are undesirable either because they have an adverse effect on product quality or because they are potentially harmful. The presence of very low levels of processing contaminants in common foods is becoming an increasingly important issue for the food industry, as developments in analytical techniques and equipment bring foods under closer and closer scrutiny. This review considers the formation of lipid oxidation products, hydrogenation of polyunsaturated fatty acids to prevent lipid oxidation and the associated risk of trans fatty acid formation. The formation of acrylamide in the Maillard reaction is described, as well as the genetic and agronomic approaches being taken to reduce the acrylamide-forming potential of cereal grain. The multiple routes for the formation of furan and associated chemicals, including hydroxymethylfurfuryl, are also described. The evolving regulatory and public perception situations for these processing contaminants and their implications for the cereal supply chain are discussed, emphasising the need for cereal breeders to engage with the contaminants issue.     

Plant growth and survival of five introduced and two native/naturalized perennial grass genotypes exposed to two defoliation managements in arid Argentina

The field performance of the native Pappophorum vaginatum, the naturalized Eragrostis curvula and various cultivars of the introduced Achnatherum hymenoides and Leymus cinereus was evaluated as potential forage resources in rangelands of arid Argentina during the warm seasons of 2007/2008 and 2008/2009. Plants of these grass species, obtained from seeds, were transplanted to the field in 2006, when they were 1 year old. During the study years, there were two defoliation managements: plants of all study genotypes either remained undefoliated (controls) or were defoliated twice a year during spring at 5 cm stubble height. Despite tiller number being lower (P < 0·05) on defoliated than on undefoliated plants, and total leaf length per unit basal area being similar (P > 0·05) between defoliation managements by mid‐spring, there were no differences (P > 0·05) in dry weight production between defoliated and undefoliated plants in all genotypes at the end of the second growing season. Plants of one or more of the introduced genotypes showed a similar (P > 0·05) or greater (P < 0·05), but not lower, tiller number per plant and per square centimetre, daughter tiller production, total leaf length and dry weight production per unit basal area than the native species at the end of the first and/or second growing seasons. These morphological variables were similar (P > 0·05) or greater (P < 0·05) in the native than in the naturalized genotype. Plant survival, however, was lower (P < 0·05, overall mean = 20%) in the introduced than in the native (>70%) or naturalized (>39%) genotypes at the end of the first or second growing seasons.     

Fabrication of electromagnetic shielding polyester fabrics with carboxymethyl chitosan-palladium complexes activation

Electromagnetic shielding polyester fabrics were prepared using carboxymethyl chitosan-palladium (CMCS-Pd) complexes as activation solution, followed by electroless nickel plating. CMCS-Pd complexes were prepared by the complexing adsorption between CMCS and Pd²⁺. The effects of reaction time and pH value on the adsorption of Pd²⁺ by CMCS were discussed. The maximum adsorption capacity was calculated as 4.27 mmol/g. CMCS-Pd complexes were characterized by ultraviolet (UV) spectrophotometer and Fourier transform-infrared (FTIR) spectroscopy. The induction time of electroless plating decreased gradually with the increase of Pd²⁺ concentration. The lowest surface resistance 125 mΩ/sq of the treated polyester fabric was obtained when Pd²⁺ concentration in CMCS-Pd complex was 1.5 g/l. The prepared polyester fabrics had excellent electromagnetic shielding effectiveness (SE) of 40–60 dB. The treated polyester fabrics were also characterized by scanning electron microscopy (SEM). Results showed that CMCS-Pd was effective to form an active catalyzed layer on polyester substrate and the 1.5 g/l Pd²⁺ was sufficient to initiate electroless nickel plating reaction. The CMCS-Pd complex activation and electroless nickel plating treatment caused small changes in the polyester fabrics’ tensile strength and air permeability.     

Composition of Typical Soil Minerals and Quantitative Analysis for Influence of Iron and Manganese Forms on Purple Soil Color in Northeastern Sichuan,China

Eurasian Soil Science - Eight soil samples from the Jurassic Shaximiao Formation (J2s) in the Sichuan Basin, China, were taken as the research object to explore the correlation and quantitative...     

圈养黇鹿对北方4种常见苗木叶片适口性浅析

为研究鹿科动物食性,探讨树叶用作鹿科动物饲料的可能性,以黇鹿为试验对象,选取北方常见榆树、刺槐、垂柳及毛白杨等4种树种新鲜叶片作为饲料,对其适口性进行分析。结果表明,黇鹿对4种叶片喜食程度依次为榆树叶、刺槐叶、垂柳叶和毛白杨叶;通过对叶片粗蛋白质含量(CP%)、酸洗纤维(ADF%)、中洗纤维(NDF%)等7种生化指标测定发现叶片中的CP含量(P=0.001)、ADF含量(P=0.025)及NDF含量(P=0.032)是影响其对叶片选择的关键因素。     

枣叶脉网络结构特征研究

叶脉是植物水和养分运输的重要通道,其网络结构具有植物种的特异性,也具有环境的适应性。利用LEAF GUI软件定量获取枣、过渡型和酸枣的叶面积、周长、闭合度、节点数等叶脉网络结构特征值,研究其分布规律和变异趋势,并比较了三者之间的差异。结果表明,酸枣的叶脉网络结构特征与枣和过渡型有显著差异;叶脉网络结构特征的变异具有连续性;酸枣的叶面积、网眼数、节点数等特征较枣小,是其对干旱、瘠薄等生长环境的长期适应的结果。     

浅析渔业科研院所学科建设的特点与策略

学科建设是现代渔业科研院所建设的基础工作。文章分析了渔业科研院所学科建设的特点,阐述了加强渔业科研院所学科建设的重要性和策略,提出了研究制订学科建设规划、加强学术带头人与团队建设、加强科研平台与条件建设、创新管理运行机制、深入对外交流与合作等加强渔业科研院所学科建设的措施,以期为渔业科研院所进一步加强学科建设提供参考。     

萘乙酸对南瓜种子萌发的影响

研究不同浓度的萘乙酸（NAA）对南瓜种子萌发及幼苗生长的影响,以期为提高南瓜种子发芽率、发芽整齐度、如何节约种子和缩短育苗周期提供参考。结果表明,10-8mg/L的萘乙酸可以增加南瓜种子的发芽率、根长、侧根数、叶绿素含量和根系活力。     

香港形式法治与实质法治二元发展路径初探

自回归以来,围绕香港法治实践的激烈争鸣,可简约为“法治一元论”范式下的形式法治主义者与实质法治主义者之间的博弈。“法治一元论”难以准确地解读法治发展的基本规律,不利于凝聚港人的法治共识。依循“法治二元论”范式下的香港形式法治与实质法治二元发展路径,既可有效地调和相互冲突的法治观念,又能确保香港法治的良性发展,维护香港的长期繁荣与稳定。