The Effect Of Scaffolding On The Acquisition Of Rowing

The aim of this thesis is to examine the nature of scaffolding in learning to row. Four studies were carried out to investigate the nature of instruction in relation to learning to row. Study 1 investigated the relationship between contingent tutoring and learning to row. Contingency tutoring was significantly related to learning to row. The coaches in this study were coaching individual boys on a one-to-one basis, in a single environment. Study 2, tried to replicate study 1, with the introduction of three other learning environments: the 'ergometer', the 'rowing tank'and the rowing boat. Unlike study 1, this study found a negative relationship between scaffolding and learning to row. There were also differences between the environments. It was therefore, necessary to conduct a further study. Study 3 was an observational study, designed to examine the nature of coaching itself. It found that, most of the coaching activity was based on generalised instructions, with only 8% of the time employing scaffolding techniques. Grouped-based instruction made up 26% of the instruction, while individual instruction made up 33%; the coach simply observed for the rest of the time. The study found differences between the environments, in terms of the amount spent on each coaching activity. Contingent tutoring varied according to the environment in which the instruction was given. Study 4 interviewed 10 coaches about their coaching. It found strong evidence of the coaches using the functions of scaffolding. The coaches also adopted different coaching strategies, based on the different learning environments, the time of the session, physical state of the boys and the physical state of the river. The theoretical, practical and methodological implications of these findings are then discussed. This thesis found that the 'learning environment' had a large impact on the nature of teaching and learning to row. Each 'learning environment' required a different approach to teaching/coaching, which in turn produced different responses from the learners'

Effects of cotton spacing on insect infestation, natural enemies and yield, Gezira State, Sudan

    In the Gezira Scheme, Sudan, cotton (Gossypium barbadense L.) has been grown under irrigation without insecticidal use for more than 30 years (1911-1945). That was probably due to the traditional growing of cotton, in the same area, under rainfed before the establishment of the Gezira Scheme.  Such practice witnessed a balanced agricultural ecological system in the cotton growing area. Since season 1945/46 till now, more than 300 insecticides and insecticide mixtures were recommended. The average yield was less than 7 kantar/feddan for upland cotton. The objective of this study was to test the effect of spacing on insect infestation, natural enemies and yield of Brazilian (LL) cotton cultivar enemies without insecticidal spraying. The crop was planted in June 20, 2012 at intra-row spacing of 10 cm, 20 cm, 30 cm and 40 cm and 50 cm with 4-6 seeds/hole and then thinned to three plants per hole, on 80 cm ridges. Insect pests and natural enemies were monitored. Results showed that the sucking insects, Jassid (Jacobiassica lybica) and the whitefly (Bemisia tabaci) appeared in July, increased in number to reach the peak in August and then decreased in October. The Brazilian (LL) cultivar was attacked by the bollworms, Helicoverpa armigera and Earias insulana. Shedding of reproductive structures due to bollworms was recorded. H. armigera resulted in higher damage of reproductive structures during August in the wider spacing (50 cm) while, the damage was lower during September. For E. insulana, damage of reproductive structures was lower in the wider spacing compared to narrow spacing during August and September. Natural shedding of reproductive structures was low during August and high during September in the widest spacing (50 m). The buildup of natural enemies started in July to reach the peak in September and decreased in October, in a density dependent pattern with sucking insect pest populations. The yield of cotton in kantar per hectare was 29.8 at 10 cm spacing (5 folds) and 14.8 at 20 cm (2.5 folds) as compared to 6 at 50 cm the recommended spacing. However, the quality, in term of stickiness, was satisfactory among all spacing under test. The study revealed that narrow spacing reflected higher yield with good quality of cotton. It is recommended to grow the Brazilian LL cotton cultivar at a spacing of 10 cm for higher yield and best quality. استمرت زراعة القطن طويل التيلة بالري الصناعي بمشروع الجزيرة بالسودان لأكثر من ثلاثين عاماً دون رش المبيدات لحماية المحصول من الآفات (1911-1945). يُعزى ذلك لزراعة القطن قصير التيلة بالأمطار ولمدة طويلة سبقت قيام المشروع. تمخض عن هذه الممارسة توازن إيكولوجي في بيئة المشروع. ومنذ  أن بدأ إدخال المبيدات لمكافحة الآفات في الموسم 1946/1945، حتى الآن تمت إجازة أكثر من 300 من المبيدات ومخاليط  المبيدات. عليه الهدف من هذه الدراسة معرفة أثر الزراعة المبكرة في مسافات متباينة على كمية ونوعية القطن المنتج. تمت زراعة القطن في 20 يونيو 2012 وعلى مسافات 10 سم،       20 سم ، 30 سم و 40 سم بين النباتات  وتمت مقارنتها مع المسافة المعيارية 50 سم و ذلك بزراعة 3 بذور في كل حفرة. تم رصد الآفات الحشرية والأعداء الطبيعية. أظهرت النتائج أن الحشرات الماصة، النطاط الأخضر (Jacobiasca lybica) والذبابة البيضاء (Bemisia tabaci) بدأتا في الظهور في شهر يوليو ووصلتا قمة التواجد في أغسطس وبدأتا في الانحسار في أكتوبر. اتضح أن الصنف تحت الاختبار  (Brazillian LL)يصاب بديدان اللوز الأفريقية (Helicoverpa armigera) والمصرية (Earias insulana). تساقط الأزهار واللوز reproductive structures)) قد دون.  التساقط نسبة للإصابة بدودة اللوز الأفريقية كان كبيراً في أغسطس في المسافات 40 سم و50 سم بينما انخفض خلال سبتمبر. بالنسبة لديدان اللوز المصرية الإصابة على الأزهار واللوز كانت قليلة على المسافات الواسعة مقارنة بالإصابة على المسافات الضيقة  خلال شهري أغسطس وسبتمبر. أما التساقط الطبيعي لهذه المكونات فقد كان قليلاً في أغسطس وكثيراً في سبتمبر عند المسافة 50 سم. زيادة الأعداء الطبيعية بدأت في يوليو ووصلت قمتها في سبتمبر ثم انحسرت في أكتوبر بمنوال الكثافة غير المستقلة عن عشائر الآفات الماصة. إنتاجية القطن بالقنطار للفدان 29.8 (5 أضعاف) للمسافات البينية 10سم و 14.8 (2.5 ضعف) للمسافات البينية 20 سم مقارنة بالمسافة البينية 50سم. نوعية القطن المنتج من حيث اللزوجة (Stickiness) كان مرضياً لكل المسافات تحت الاختبار. أفضت الدراسة إلى أن المسافات البينية المتقاربة أدت إلى زيادة الإنتاج مع جودة نوعية المنتج للقطن. عليه نوصى بزراعة صنف القطن البرازيلى (LL) بمسافة 10 سم بين النباتات ليعطي أعلى إنتاجية ونوعية من القطن

Бактерицидный эффект He-Ne лазера (632,8 нм) на колонии Staphylococcus aureus

The bactericidal effect of 632.8 nm low level laser has been studied in order to point out both the effective power and laser exposure time on Staphylococcus aureus, which is reported to be involved in several dermatology problems. Low level laser has been reported to be useful for infected wounds, tissue necrosis, nerve injury, osteoarthritis or other chronic pain syndromes. Numerous studies have been conducted to quantify the effective laser parameters, i.e. dose, power, and exposure time, which ultimately leads toward clinical implementation. Staphylococcus aureus bacteria colonies were exposed to laser doses with powers of both 1 and 3 mW at different exposure times varies between 3 to 30 minutes. The bacterial colonies were isolated from a patient with inflamed wounds. Two sets of bacterial colonies were prepared to be exposed to laser beam. Next, the bacterial colonies were compared before and after exposing them to laser doses. The results showed that laser sessions have reduced the number of the bacterial colonies for both doses; 1 and 3 mw at the different exposure times and concentrations. The results revealed significant dose dependent bactericidal effects of He-Ne laser on Staphylococcus aureus at 3 mW for 30 minutes, which was found to be more effective in reducing the amount of bacteria to the less than 2% of its initial count. The results exhibited the reduction of the number of colonies as a function of exposure time. Appropriate doses of 632.8 nm can kill Staphylococcus aureus, suggesting that a similar effect may be used in clinical cases of bacterial infection.Нами был изучен бактерицидный эффект низкочастотного лазера с длиной волны 632,8 нм с целью определения эффективной мощности и времени воздействия лазера на бактерии Staphylococcus aureus, участвующие в патогенезе ряда дерматологических заболеваний. Ранее проведены многочисленные исследования количественной оценки эффективных параметров лазера: световой дозы, плотности мощности и времени воздействия. В настоящем исследовании на колонии бактерий Staphylococcus aureus воздействовали лазерным излучением мощностью 1 и 3 мВт при разном времени воздействия (от 3 до 30 мин). Колонии бактерий были выделены у больного с воспаленными ранами. Воздействие лазером уменьшило количество бактериальных колоний во всех экспериментах. Результаты выявили значительное дозозависимое бактерицидное воздействие гелий-неонового лазера на Staphylococcus aureus. При мощности 3 мВт при воздействии в течение 30 мин количество бактерий снизилось до уровня менее 2% от его первоначального количества. Результаты показали уменьшение количества колоний в зависимости от времени воздействия. Лазерное излучение на длине волны 632,8 нм обладает бактерицидным действием в отношении Staphylococcus aureus

An overview of factors responsible for geographic distribution pattern of ixodid ticks in the Sudan

Tick fauna in the Sudan comprises over 70 species prevalent in diverse ecological zones. Among these are the most economically important ticks in Africa, namely Rhipicephalus appendiculatus, Hyalomma anatolicum, Amblyomma variegatum, Amblyomma lepidum, Rhipicephalus (Boophilus) decoloratus and Rhipicephalus (Boophilus) annulatus. Several factors determine the dynamic changes of tick distribution in the Sudan. These are animal movement either for trade, nomadism, or migration due to civil unrest etc., habitat modification such as deforestation, large-scale mechanized cultivation and urbanization; drought and desertification, and global climate change. The accelerated change in tick distribution results in outbreaks of several tick-borne diseases. Examples of these are East Coast fever, tropical theileriosis, malignant ovine theileriosis, heartwater and babesiosis by Babesia bovis. Emergence of these diseases in districts believed to be free is alarming and has adverse effects in the process of animal resources development. This communication discusses distribution patterns of the economically important livestock ticks in the Sudan and identifies new zones where ticks have established and the possible factors determining such distribution.Keywords: Distribution, Factors, Livestock, Sudan, Ticks

Marine pollution of the Sudanese coast

The increase of heavy traffic in transporting oil along the Red Sea, causes a serious threat of oil pollution in Sudanese waters. This threat has mainly increased after the second stage of the Suez Canal Development Project which was carried out and completed in 1985. To some extent, marine pollution by substances other than oil already exists along the Sudanese coast and most of it comes from shore-based sources which are located on the coast north and south of Port Sudan town. This thesis will provide an overall review of the physical characteristics of the Red Sea and the Sudanese coast in particular. It also identifies and provides suitable means of monitoring, controlling and combating the existing marine pollution and any pollution resulting from a major disaster, with regard to the establishment of a MARITIME SAFETY ADMINISTRATION in SUDAN

COMPARATIVE HISTOPATHOLOGICAL STUDY BETWEEN AMIKACIN AND TOBRAMYCIN GIVEN ALONE AND IN COMBINATION WITH CALCIUM GLUCONATE IN RABBITS

An experiment conducted to explore a histopathological comparison between tobramycin sulphate and amikacin sulphate, and to explore the role of calcium gluconate in antagonizing or reducing the main toxic side effects of tobramycin and amikacin like nephrotoxicity.The experiment was designed to study the effects of therapeutic and triple doses of tobramycin and amikacin alone, and with calcium gluconate in rabbits. This experiment lasted for one month and was divided into three periods (pretreatment period for 7 days, treatment period for 14 days and recovery period 7 days). The results showed that tobramycin and amikacin differ in their toxic effects potential at both therapeutic and triple doses. Tobramycin caused more pathological changes than that changes caused by amikacin, the main changes in renal tissue that caused by therapeutic dose of tobramycin are hydropic swelling of renal tubular epithelial cells ,vascular congestion of glomeruli ,while the triple dose of tobramycin caused shedding of renal tubular epithelial cells, formation of hyaline casts in tubular lumina , loss of brush border, hydorpic swelling of renal tubular epithelial cells, foci of moderate to heavy mixed acute and chronic inflammatory cell infiltration (in form of neutrophils, lymphocytes, plasma cells and occasional eosinophil). Pretreatment with calcium significantly improved the study to the levels almost similar to that of control group for both drugs, and gave complete protection from toxic effects of amikacin, and complete to partial protection with tobramycin accordingly with their doses

Bioaccumulation of hydrocarbon compounds in the muscle of three aquatic birds in Um Alnaaj Marsh, Iraq

The current study was conducted to determine the concentrations and origins of total petroleum hydrocarbon TPHs and polycyclic aromatic hydrocarbons PAHs in three bird species of Anas platyrhynchos, A. crecca and A. acuta collected from November 2020 to April 2021 in Um Alnaaj Marsh, Iraq. Based on the results, the TPHs (g/g.dry weight) in muscle tissues were 13.79 and 16.74 in A. platyrhynchos, 40.84 and 43.0 in A. crecca, and 10.08 and 11.18 in A. acuta during winter and autumn, respectively. The PAHs (ng/g.dw) in muscle tissues were 41.22 and 146.86 in A. platyrhynchos and 31.17 and 42.98 in A. crecca during winter and autumn, respectively, whereas it was 24.41 to 75.51 in A. acuta during autumn and winter, respectively. The lower molecular weight PAHs was less than higher molecular weight PAHs in all bird species throughout the period study. The origins of PAHs in muscles tissues of the studied bird species were estimated according to the ratio of LPAHs/HPAHs, Fluo/Pyr, Phe/Ant, Inpy/(Inpy+BghiP), Ant/(Ant+Phe), and BaA/(BaA+chr) and based on the findings, they were mostly pyrogenic and few petrogenic. The results also showed that the bird species have the ability to accumulate these compounds in their muscles according to values of BCF which is between 2.29 and 5.81 in A. crecca and A. platyrhynchos, respectively. These bird species were contaminated with petroleum compounds and the consumption of their meat may pose public health hazards