Allelopathic effects of Polygonum aviculare L.

Therefore, allelopathy appeared to be the dominant component of the interference, with competition probably accentuating its effects. Polygonum aviculare was inhibitory to Gossypium barbadense L. and Sorghum bicolor (L.) Moench indicating that allelopathy is an important component of the interference by Polygonum against crop yields. In spite of the moderate allelopathic effects against cotton and sorghum it may still be possible to plant Polygonum aviculare between rows of these crops or to supply a light mulch between rows to control various weeds including Cyndon dactylon and some other weeds.Polygonum aviculare was observed to spread rapidly into heavy stands of Cynodon dactylon (L.) Pers. indicating a strong interference against Cynodon dactylon. Measurements of selected soil minerals and physical factors indicated that competition was probably not the chief cause of that interference. Soil collected under senescent Polygonum was very inhibitory to all test species except Sporobolus pyramidatus (Lam.) Hitch., suggesting the presence of inhibitory compounds. Tops and roots of Polygonum, root exudates, and leachate of the tops inhibited seed germination and seedling growth of more test species.Four inhibitors were isolated from living Polygonum plants, three of which were glucosides. Four different inhibitors were isolated from Polygonum residues and soil under Polygonum stands, and none of these occurred in soil from Cynodon dactylon stands. Three of these were glycosides containing both fructose and cellobiose as the sugars. Color reactions of all the inhibitors indicated that they are phenolic in nature. All the inhibitors reduced seed germination and/or seedling growth of Chenopodium album L. Moreover some of them inhibited growth of different strains of Rhizobium and Azotobacter

Diasporic virginities: social representations of virginity and identity formation amongst British arab muslim women

This study compares how practising and non-practising British Arab Muslim women position themselves in relation to representations of virginity. Overall, in our qualitative study, we found that representations of culture and religion influenced social practices and social beliefs in different ways: non-practising Muslim women felt bound by culture to remain virgins, while practising Muslim women saw it as a religious obligation but were still governed by culture regarding the consequences of engaging in premarital sex. Interestingly, some practising Muslim participants used Mut’a (a form of temporary ‘marriage’) to justify premarital sex. This, however, did not diminish the importance of virginity in their understanding and identification as Arab women. In fact, this study found that virginity, for the British Arabs interviewed, embodied a sense of ‘Arabness’ in British society. Positioning themselves as virgins went beyond simply honour; it was a significant cultural symbol that secured their sense of cultural identity. In fact this cultural identity was often so powerful that it overrode their Islamic identities, prescribing their behaviour even if religion was seen as more ‘forgiving’

The Effects of Individualized Learning and Emotional Intelligence in Females' Intermediate Schools in the Kingdom of Saudi Arabia

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A feasibility study of small hydro power for selected locations in Egypt

One of the biggest challenges facing the world today is to provide access to a safe and affordable electricity supply. Depending on the river flow, small-hydropower is often a cost-effective source of renewable energy. Egypt is home to part of Africa's longest river and it is a relatively reliable source. Many small hydropower plants can be installed in run-of-river schemes or implemented in existing river infrastructure. We argue that it is essential for the Egyptian government to make use of hydropower resources, not only to meet the increasing demand but also to reduce fossil fuel use, and associated environmental pollution. This paper investigates the small hydro energy potential at selected locations in Nile Delta-Egypt and presents a feasibility study of small hydropower for these locations. The head and water flow rates for the past five years are used to find out the hydro energy potential. The annual energy of three different small hydro turbines is calculated for eight selected regions in Nile Delta-Egypt. The analysis includes a comparison between energy outputs from the three hydro turbines types. Furthermore, a MATLAB program is built to compute the efficiency of the studied turbines in each site at different heads and water flow rates. It is found that the use of Crossflow and Kaplan turbines with different sizes can enhance electric energy production at the selected sites. Keywords: Small-hydro, Hydro turbine efficiency, Economic analysis, Hydro energy assessmen

Micropoma niloticum (Del.) Lindb. (Musci) with corn-like stem bases

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