Determination of Polycyclic Aromatic Hydrocarbons in Wastewater,Sediments, Sludge and Plants in Karak Province,Jordan

Analysis for sixteen types of Polycyclic Aromatic hydrocarbons (PAHs)from samples of raw and treated wastewater, sediments, sludge andplants growing along treated wastewater way was performed inOctober 1997. The collection sites represent two wastewatertreatment plants (WWTP) receiving different types of wastewaterand one site from disposal of raw wastewater in the city ofKarak in southern Jordan.Wastewater treatment efficiency showed removal of PAHs throughsettling tanks and adsorption on sediments after treatment. Theremoval percentage ranged from 44–100% for individual PAH.PAHs were widely distributed at various levels in rawwastewater, treated wastewater, sludge, sediments and plants.The highest concentration was observed in sludge and the lowestin plants. There was a variation in PAHs concentration betweenthe three investigated sites which was attributed to theefficiency of treatment, period of contact with the wastewater,and the nature of activities. The WWTPs were capable or reducingPAHs contamination in water, up to 40% of the total PAHs byadsorption on sludge and sediments.     

Influence of Drought Applied at Different Growth Stages on Kernel Yield and Quality in Maize (Zea Mays L.)

Drought severely affects yield and its quality in different plants. In a field experiment, maize was exposed to drought stress at vegetative, silking, and kernel-filling growth stages to determine the drought-induced changes in kernel yield and quality traits. The experiment was laid-out in a randomized complete block design with four replications. Withholding water at the vegetative stage was very effective in increasing protein, total amino acids, total soluble sugars, glucose, and sucrose contents in maize kernels. In contrast, drought applied at the kernel-filling stage increased the total free amino acids, total phenolics, and activities of catalase (CAT) and ascorbate peroxidase (APX) in maize kernels. Drought at the vegetative stage improved the kernel quality while at the silking stage severely affected kernel yield in maize. Taken together, the results suggested that incidence of drought should be avoided at the silking stage to minimize kernel yield losses and decrease in kernel quality in maize.     

博斯腾湖湿地边缘带农田土壤重金属的污染风险评价

对新疆博斯腾湖湿地边缘带农田土壤中8种重金属元素(As、Cd、Cr、Cu、Mn、Ni、Pb和Zn)地球化学特征进行分析。采用污染负荷指数(PLI)、潜在生态风险指数(RI)和生态风险预警指数(IER)对农田土壤重金属污染与环境风险进行评价。结果表明:(1)湿地边缘带农田土壤Pb和Zn呈现重度污染,As、Cd、Cr和Ni轻度污染,Cu轻微污染,Mn无污染。土壤As、Cd、Cr、Cu、Ni、Pb和Zn平均含量处于轻微风险水平。Cd是污染程度与生态风险等级最高的重金属元素;(2)湿地边缘带农田土壤PLI平均值为1.43,呈现轻度污染,RI平均值为20.62,呈现轻微生态风险状态,IER的平均值为–4.53,呈现无警态势。湿地边缘带PLI、RI与IER空间分布格局基本一致;(3)湿地边缘带农田土壤Pb与Zn来源主要受到人类活动的影响,Cr、Cu、Mn与Ni来源主要受到土壤地球化学作用的控制,As与Cd受自然因素和人为因素共同影响。     

Interaction of Rhizobium and Pseudomonas with Wheat (Triticum Aestivum L.) in Potted Soil with or Without P2O5

The effect of inoculation of Rhizobium or Pseudomonas, or both, in the presence and absence of phosphorus pentoxide (P₂O₅) fertilizer on wheat yield was tested. The experiment was conducted outdoors in potted soil during two consecutive years under natural conditions. Rhizobial strain (Thal 8-chickpea nodulating bacteria) and Pseudomonas strain (54RB), both indigenous P solubilizers were applied in broth culture at seedling stage. Fertilizer in the form of P₂O₅ was an additional treatment applied at sowing time. Results revealed that inoculation of Pseudomonas strain in presence of phosphorus (P) fertilizer increased yield up to 41.8% when it was compared with only P fertilizer applied. Co-inoculation of Rhizobium and Pseudomonas strains with the P₂O₅ treatment however resulted in increased grains yield by 10% over the P₂O₅ treatment alone. It is inferred that inoculation with Rhizobium and Pseudomonas combined with P₂O₅ is not only environmentally beneficial but also economically sound and productive, with wheat yield increases of 10% to 42%.     

新疆薄罗藓科(Leskeaceae)植物分类的初步研究

通过对产自新疆的薄罗藓科5属8种的分类学研究,包括多毛藓属Lescuraea Bruch & Schimp. in B.S.G. 的弯叶多毛藓L. incurvata (Hedw.) Lawton,密根多毛藓 L. radicosa (Mitt.) Moeck.,石生多毛藓L. saxicola (Schimp. in B.S.G.) Mol. in Lor.;薄罗藓属Leskea Hedw. 的薄罗藓L. polycarpa Hedw. ;细罗藓属Leskeella (Brid.) Loeske 的细罗藓L. nervosa (Brid.)Loeske ;细枝藓属Lindbergia (C. Müll) Broth. 的中华细枝藓L. sinensis (C. Müll) Broth. ,以及假细罗藓属 Pseudoleskeella Kindb. 的假细罗藓P. catenulata (Brid. ex Schrad.) Kindb.和瓦叶假细罗藓P. tectorum (Brid. )Kindb.。其中,薄罗藓属Leskea Hedw.为新疆新记录属;薄罗藓Leskea polycarpa Hedw. 和密根多毛藓Lescuraea radicosa (Mitt.) Moeck. 是新疆新记录种。根据标本形态特征,编制了新疆薄罗藓科植物分属、分种检索表,简要讨论了其生境和地理分布特点。     

The potential of precision surface irrigation in the Indus Basin Irrigation System

In this research we explore the potential of precision surface irrigation to improve irrigation performance under the warabandi system prevalent in the Indus Basin Irrigation System. Data on field dimensions, field slopes along with characteristic soil infiltration properties and outlet discharge were collected through a survey of a sample tertiary unit of Maira Branch Canal, Khyber Pakhtunkhwa Province, Pakistan. The performance of all fields in the tertiary unit was analysed and reported in aggregate, with detailed results of one field presented for illustration. The objective is to determine the optimum field layout, defined as the number of border strips, for the observed field characteristics to maximize performance. The results indicate that performance improvement is relatively easily achievable through changes in field layout within current irrigation services. Estimated application efficiency is sensitive to the selected depth of application, and it is important that a practical depth of application is selected. We recommend a depth of application of 50 mm and show how this is achievable and leads to a low quarter distribution uniformity of 0.750 and an application efficiency of 80 %. We also explore the feasibility of a 10-day warabandi rather than the 7-day warabandi and show that there is no significant change in the performance under a 10-day warabandi.     

新疆伊犁地区野果林的群落特征及保护

新疆伊犁地区是我国野果林分布的主要地段.通过野外调查和资料收集,共获得67个野果林群落样方,分析了新疆伊犁地区野果林的群落结构及其分布特征.结果表明:野果林林下物种丰富,共记录维管束植物46科141属207种.群落分类将野果林划分为野核桃林、野苹果林、野杏林和野生樱桃李林4种类型.野杏林和野生樱桃李林的物种丰富度显著高...     

Comment on "Protein sequences from mastodon and Tyrannosaurus rex revealed by mass spectrometry"

We used authentication tests developed for ancient DNA to evaluate claims by Asara et al. (Reports, 13 April 2007, p. 280) of collagen peptide sequences recovered from mastodon and Tyrannosaurus rex fossils. Although the mastodon samples pass these tests, absence of amino acid composition data, lack of evidence for peptide deamidation, and association of alpha1(I) collagen sequences with amphibians rather than birds suggest that T. rex does not.