Mineral Composition and Soil-Plant Relationships for Common Guava (Psidium guajava L.) and Yellow Strawberry Guava (Psidium cattleianum var. lucidum) Tree Parts and Fruits

The mineral compositions of the fruit and tree parts of common guava, Psidium guajava L., and strawberry guava, Psidium cattleianum var. lucidum, were determined. The study occurred during three seasons at six locations in Hawaii to assess guava as feed for livestock. Guava bark contained the greatest concentrations of calcium (Ca) and ash; leaves the greatest concentrations of magnesium (Mg), sulfur (S), sodium (Na), boron (B), and manganese (Mn); and the shoots had the greatest concentrations of nitrogen (N), phosphorus (P), and potassium (K). The leaves and the shoots had the greatest concentrations of copper (Cu) and iron (Fe). Between guava and waiwi, guava had greater concentrations of most minerals except for Na in all plant parts, and Mg and ash in the leaves. Guava leaves and shoots meet the macromineral requirements for various phases of sheep, goat, and beef cattle life cycles with the exception of P and Na. Guava shoots do not meet Mn requirements for lactating cows.     

基于阅读资源多元化的读者阅读需求分析

电子技术的发展，数字图书的出现，形成了阅读资源多元化发展的新趋势，使传统阅读资源受到强烈冲击和影响。虽然阅读的栽体在不断变化，但不变的是读者的需求，只要是有价值的资源，就是读者愿意接受的阅读资源。在相当长的时间内，传统阅读和数字阅读资源会优势互补、各显特色，共生共存。     

浅谈科技论文写作之常见问题及对策

针对目前科技论文写作中存在的摘要、关键词、引言、正文、结论、参考文献等不规范的问题进行简要描述,提出相应对策,并对盲目投稿问题提出自己的观点。以期对学术期刊的文章作者提供参考和帮助。     

Tissue-specific antioxidative and neurotoxic responses to diazinon in Oreochromis niloticus

The purpose of this study was to evaluate oxidative stress and neurotoxic potential of organophosphorus (OP) insecticide diazinon in the sentinel freshwater fish, Oreochromis niloticus. Antioxidant and acetylcholinesterase (AChE) enzyme activities and malondialdehyde (MDA) and protein levels were measured spectrophotometrically in gill, kidney, alimentary tract, and muscle tissues of fish treated with sub-lethal diazinon concentrations for 1, 7, 15, and 30 days. Dose-dependent inhibitions of AChE were observed in all the experimental fish. On the contrary of alimentary tract, MDA levels were elevated in kidney and muscle and gill was not affected. AChE and MDA levels intercorrelated in kidney and muscle tissues. Diazinon had increased superoxide dismutase (SOD) activities in all the tissues, while kidney was the most affected tissue. Tissue-specific alterations were observed on catalase (CAT) and glutathione peroxidase (GPx) activities; however, the activities were not changed in gill and muscle tissues for GPx and in gill, muscle, and kidney tissues for CAT. Protein levels decreased in kidney, muscle, and alimentary tract, while increased in gill and alimentary tract in 15 days. With respect to these results, diazinon has oxidative and neurotoxic potentials in O. niloticus. Observed changes with diazinon treatment were generally tissue-specific and dose-dependent.     

Landscape ecology of <Emphasis Type="Italic">Phragmites australis</Emphasis> invasion in networks of linear wetlands

The interaction between landscape structure and spatial patterns of plant invasion has been little addressed by ecologists despite the new insights it can provide. Because of their spatial configuration as highly connected networks, linear wetlands such as roadside or agricultural ditches, can serve as corridors facilitating invasion at the landscape scale, but species dynamics in these important habitats are not well known. We conducted a landscape scale analysis of Phragmites australis invasion patterns (1985–2002 and 1987–2002) in two periurban areas of southern Québec (Canada) focusing on the interaction between the network of linear wetlands and the adjacent land-uses. Results show that, at the beginning of the reference period, the two landscapes were relatively non-invaded and populations occurred mostly in roadside habitats which then served as invasion foci into other parts of the landscape. The intrinsic rates of increase of P. australis populations in linear anthropogenic habitats were generally higher than those reported for natural wetlands. Riparian habitats along streams and rivers were little invaded compared to anthropogenic linear wetlands, except when they intersected transportation rights-of-way. Bivariate spatial point pattern analysis of colonization events using both Euclidian and network distances generally showed spatial dependence (association) to source populations. An autologistic regression model that included landscape and edaphic variables selected transportation rights-of-way as the best predictor of P. australis occurrence patterns in one of the landscapes. Given the high invasion rates observed, managers of linear wetlands should carefully monitor expansion patterns especially when roads intersect landscapes of conservation or economic value.     

Pesticide use and residues on Queensland wool

Objective To determine practices for control of louse infestation and blowfly strike in Queensland sheep flocks that are associated with organophosphorous and synthetic pyrethroid residues on wool.
Design Information on residues was obtained from a survey of Queensland wool clips. Information on pesticide use was obtained from a trace-back postal survey. The association between pesticide use and residues was assessed using generalised linear models, controlling for potential confounding by flock location.
Procedure Between 1995 and 1997 Queensland wool clips were randomly sampled. Samples were tested for the presence and amount (mg per kg of greasy wool) of organophosphorous and synthetic pyrethroid pesticides. A questionnaire seeking information on flock characteristics and pesticide use was sent to the manager of each flock from which a wool sample was tested.
Results The median amount of OP and SP residue was 0.8 and 0.25 mg/kg, respectively, and 91 and 95% of wool samples contained < 8 mg/kg of OP and SP residues, respectively. The frequency of OP pesticide use for louse control was significantly (P = 0.005) associated with mean OP residue amount, and the timing of SP use for louse control, in relation to shearing, was significantly (P < 0.001) associated with mean SP residue amount.
Conclusion Most Queensland wool clips have acceptable amounts of residues after the use of OP and SP pesticides, but wool growers can further reduce residues by effectively controlling louse infestation with pesticide applications early after shearing and the use of non-chemical methods of ectoparasite control.     

农药产品中添加未经登记成分的调查与分析

通过连续6年的福建省农药市场监测,对擅自添加未经登记农药成分的278份样品进行统计分析,研究表明:被添加农药的产品主要为杀虫剂,剂型主要为乳油、可湿性粉剂,多登记在蔬菜、果树、茶树、水稻、棉花上;添加的农药品种主要为有机磷类和拟除虫菊酯类杀虫剂,其防治对象与原产品相比有的属于防治谱相同,有的属于扩大杀虫谱。同时指出该行为的危害性,提出加强监管、出台检测标准和判定标准的建议。     

养护者受益权的界定及优位

分析养护者受益权的主体、客体、内容及养护者受益权的优位强势的含义、必要性。     

施肥与火鹤叶片营养状况之间的关系

本文研究了施肥与火鹤叶片营养状况之间的关系．结果表明，营养元素的供给情况直接影响着火鹤叶片的生长发育；在北京地区栽培火鹤时，在施用矾肥水的基础上，再增加适量的磷酸二氢钾和硫酸锌，可有效地促进火鹤的生长发育     

小麦淀粉合酶基因I的克隆及反义和RNAi载体的构建

采用RT-PCR方法从小麦品种豫教2号发育的籽粒中克隆出淀粉合酶I基因(starch synthase I,SSI)部分cDNA片段(795 bp)(GenBank No.EF221762),同源性比较结果显示,它与GenBank上已报道的SSI基因有高度同源性。以p WM101质粒为基础,构建了由35S启动子调控的SS I基因的反义表达载体p WM101SSI;另外,还以pFGC5941质粒为基础,构建了SSI基因的RNAi载体pFGC5941SSIsa,这些载体的构建为研究此基因的功能奠定了基础。