Vol. 20 Issue 4
A H Zakaria
Under ordinary daylight (14L: 10D), the occurrence of oviposition and ovulation in the domestic hen is normally restricted to an 8-10 h period of the day. The mechanism(s) which restricts the occurrence of oviposition and ovulation to a certain period of the normal day is not understood. Among factors proposed are a small daily surge of LH occurring at the onset of darkness; graded facilitatory influences associated with the open period; and products of post ovulatory follicles (POF).
There is considerable evidence supporting the role of gonadotropin and progesterone on follicular growth and maturation and functional maintenance of the ovary in the hen. Recently, however, there is an ever-expanding list of factors that may be involved in establishing follicular growth and ovulation, currently including the germinal disc region, growth factors, macrophages, plasminogen activator, ornithine decarboxylase, inhibin, activin, follistatin, relaxin, arginine vasotocin, oxytocin, prostaglandines, vasoactive intestinal peptide, and their interactions.
Based on the previous considerations and the data presented in this review, it may be suggested that control of follicular development in laying hens is the result of several physiological changes which still need to be determined. In conclusion, however, ovarian function of laying hens is the end result of a complex series of events accomplished by a major control (FSH, LH, P4) and its modulators (growth factors, inhibin, ornithine decarboxylase, etc). The role of these factors as potential modulators of follicular growth and ovulation needs further investigation.
Egg production by laying hens declines with the progress of age. This decline in egg production with age is an indication of decrease of ovulation. Further, as the hen ages, the interval between ovulation increases and the result is a shorter sequence and a decrease in egg production. There is strong evidence for the role of proteolytic enzymes on follicular rupture in the domestic fowl. However, mechanism(s) controlling sequence termination is poorly understood. In this respect, there are several old theories for the explanation of the mechanism relating to sequence termination. Briefly, one of these systems regulates follicular maturation and the second system regulates the timing of the preovulatory surge of LH. Some recent data, however, suggest differences in follicular growth and maturation between genotypes of birds. It has also been suggested that the activity of the pituitary-ovarian axis in white laying hens is greater than that of brown laying hens. Additionally, the adrenal gland has been given a role in timing of ovulation in the hen.
N S Botros
Extensive rock alterations are a clearly visible characteristic of most Egyptian gold deposits and occurrences. The alterations occur either surrounding the auriferous quartz veins and/or structurally controlled by specific structural features, such as fractures and shear surfaces.
Some samples of these alteration zones have proved to be anomalously enriched in gold while others are completely barren. Accordingly there is a controversy on the merit of alteration zones as a good lead to gold. Here, the various types of wall-rock alterations are reviewed with a discussion on the possible reactions that could have generated them. It is concluded that two main styles of alterations could be recognized in the field. The first results during the liberation of gold from the source rocks, and is characterized by being widely distributed and spatial relation to major structures. The second style, however, is related to the deposition of gold and is recognizable only within a few meters of the auriferous quartz veins. The potentiality of each style is discussed and some applications of the concept are offered.
In general, alterations accompanying the liberation of gold are not completely devoid of gold, but may still retain some gold depending on the mineralogical siting of gold in the source rocks. Moreover, this type of alteration is a good criterion for the presence of gold in nearby sites. Alterations accompanying deposition of gold, on the other hand, constitute a good target for gold. particularly the portions that are dissected by minor quartz veins, veinlets and stock works (silicification) where gold is believed to migrate to such sites with silica liberated during the different types of alterations.
The presence of some efficient precipitants, such as sulphides, carbonates, clay minerals, sericite, iron oxides, chlorite and graphite in the alteration zones is a good indicator of the potentiality of the alteration zone.
S.A.S. Omar
Management of lands for a variety of uses requires knowledge of sensitive areas so that effective land use strategies can be designed. Soil surveys provide baseline information that can be used for land use evaluation In this study, the Kuwait soil information system, which is based on a field survey at reconnaissance level (1:100.000 scale), was used to generate suitability information and maps for wildlife habitats and recreational camping areas.
Land use suitability for wildlife habitat and recreational camping determined by interpreting soil property information from the soil survey database against criteria established for Kuwait's conditions. Using a geographic information system, maps were developed, based on interpretation of the soil survey map unit component soils, and used to show the suitable areas was areas.
Results showed that 87% of the land was classified as "well suited" and "suited" for wildlife habitats and that 56% of the land had "severe limitations" for recreational camping Soil information, when expressed using suitability criteria, can assist with land use evaluation and provides valuable information for screening areas.
T.A. Al-Turki, H.A. Al·Olayan and K. Swarupanandan
Dianthus cyri Fisch. & Mey., a Southwest Asian species, earlier reported from Oman and UAE in the Arabian Peninsula, is reported from Jebel Aja, in the Hail Province, which is a new record for Saudi Arabia. The species is described and illustrated pointing out its characteristics and differences from other species found in Saudi Arabia.
K.F. Elkhalifa
From the herbalists' experience in Khartoum State, central Sudan, and literature reviewed in the field of plant medicine, twelve botanical treatments for eight skin diseases are documented, These are highlighted by classification, botanical characterization, application and usage, besides chemical composition. The trees which are dealt with include: Acacia nilotica (L) Wiild.ex Del., Azadirachta indica A. Juss, Balanites aegyptiacal (L) Del, Calotropis procera (Ait.) Ait.f, Ficus carica L., Hyphaene thebaical (L.) Mart., Juniperus communis L., Khaya senagalensis (Desr.) A. Juss, Lawsonia inermis L., Olea europia L., Sclerocarya birrea (A.Rich.) Hochst., Ziziphus spina-christi (L.) WiUd.
M.G. Qadri, H.R. Takruri and S.K. Tukan
The objective of this work is to study the effect of two different means of nutrition education on body weight of obese and overweight girls. Forty two Jordanian females aged between 16-22 years were divided into two equal groups: one received nutrition education through a leaflet alone (G1) and the other (G2) received individual counseling in addition to the leaflet. The study lasted for 24 weeks. The first stage lasted for 12 weeks during which weight was taken every two weeks, and the second stage, a follow-up stage, lasted for another 12 weeks during which no contact was made with the subjects. At the end of the first stage of the study, the mean weight loss for G 1 was 1.5 kg, and for G2 was 4.3 kg. Changes in BMI were parallel to changes in body weight. At the end of the follow-up stage, the two groups did not differ significantly in their mean weights. It is concluded from this study that nutrition education based on well planned simplified leaflet could be effective in long term weight control.
M. Matou, A. Shareet, M. Mstari
The objective of this study aims possibilities of development of the drills of Thuja of berbery of a forest solid mass of the area of Tlemcen and Tiaret (in the West of Algeria).
We contributed to this work by study of some basic properties of the wood of Thuja of berbery Tetraclinis articulata (density, radial withdrawal, tangential withdrawal, resin rate, average width of cerne) highlighted of action of the factors of the medium on its properties.
The results obtained note that, the wood of Thuja has a raised density, it is qualified like a heavy wood, has raised enough withdrawals, the resin east rate is depended conditions edapho-ecological where develops. From these results, we have concluded that this gasoline can be used in the sector of industry or even title that the other gasolines
Ahmed A. Ammar, Aboulhoda. M. Elserafy, Atef A. Ismail and Alaa A. Aref
High-sensitivity multi-channel aerial gamma ray spectrometric survey conducted over the studied Abu-Had area, Central Eastern Desert, Egypt (Lat. 26°:20' and 26°: 35' North, long. 32° 40' and 33°:20' East) provides reliable measurements of the apparent surface lithologic concentrations of potassium (K), equivalent uranium (eU), and equivalent thorium (eTh). These data can be expressed in the form of nine radio spectrometric parameters of absolute, ratio and reverse ratio values: K, eU, eTh, eU/eTh, eU/K, eTh/K, eTh/eU, K/eU and K/eTh.
Because the nine parameters taken three at a time result in a total of 84 combinations, the choice of which combination to use should include consideration of the purpose of the aerial geophysical survey and geochemical models of interest to the interpreter. In the present research, the ternary images were produced from the four following combinations: eU, eTh and K (three radioelement composite colour image), eU, eU/eTh and eU/K (uranium composite colour image), eTh, eTh/eU and eTh/K (thorium composite colour image) and K, K/eU and K/eTh (potassium composite colour image).
The ternary (three- component) image method is an effective method for displaying in a single image any three radio spectrometric parameters. Since a distinct colour hue is used to represent each ternary ratio on the map, zones with similar temary ratios will be represented by a unique colour. This distinct relationship between colour hue and ternary ratio allows the map to represent the surface lithologic radioelement distributions better than any one alone of the nine radio spectrometric parameters. The generated four temary radioelement maps provide a partial synthesis of the radio spectrometric data that can be used as an aid to lithologic discrimination based on colour differences. Furthermore, they highlight zones of preferential radioelement enrichment and potassic alteration zones. Consequently, they enabled narrowing down favourable target areas for detailed ground geological, geophysical and geochemical follow up for mineral exploration purposes.
M.S. Abido
After two years of extensive preparations, the World Summit on Sustainable Development was held in Johannesburg, South Africa 26th August to 4th September 2002. The summit addressed several topics including: water, energy, health, agriculture, biodiversity, crosscutting issues and the implementation plan. The summit adopted at the end of its deliberations a political declaration and an implementation plan.
The latter contained principles and directions in the major areas of work, which included more than 30 goals. In its context, the implementation plan reaffirmed the importance of sustainable development as an approach and program of work to achieve sustainability. It renewed the international commitments aiming at poverty eradication and environmental conservation. Additionally, it strengthened and broadened the concept of sustainable development. It gave special attention to the development needs of Africa and welcomed other regional initiatives. The views of civil society were given high stand in recognition of the key role that it can play in the implementation of the outcomes of the summit, and in building and promoting partnerships.
The most prominent achievement of the summit were setting goals to alleviate poverty, secure safe drinking water and basic sanitation needs, use and produce environmentally safe chemicals, develop integrated water resources management, and improve access to environmentally sound energy services. Other targets included conservation of oceans fish stocks, enhancement of health education, reducing percentages of children and mother deaths, and reducing the spread of HIV virus. The plan addressed the means of implementation and elaborated on institutional frameworks for sustainable development. Views were different on the outcomes of the summit among stakeholders according to their stands.