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أثر استخدام الحاسوب (الكمبيوتر) فى تنمية مهارات الكتابة الوظيفية لدى طلاب المرحلة الثانوية بالمملكة العربية السعودية
No full textالملخص العربي مشكلة البحث:
تحددت مشكلة البحث الحالى فى حاجة ميدان تعليم اللغة العربية إلى أساليب جديدة لتعليم الكتابة الوظيفية فى المرحلة الثانوية بغرض تحسين مهاراتها.
ولمواجهة هذه المشكلة تم الإجابة عن التساؤلات الآتية:
1- ما مهارات الكتابة الوظيفية المناسبة لطلاب الصف الأول الثانوى؟
2- ما صورة البرنامج المقترح باستخدام الحاسوب لتنمية مهارات الكتابة الوظيفية لدى طلاب المرحلة الثانوية؟
3- ما أثر استخدام البرنامج المقترح فى تنمية مهارات الكتابة الوظيفية لدى طلاب المرحلة الثانوية؟
حدود البحث:
اقتصر البحث الحالى على:
- دراسة أثر استخدام الحاسوب فى ثلاثة من مجالات الكتابة الوظيفية المقررة على طلاب الصف الأول الثانوى طبقا للمقرر الوزارى لعام 1430/1431هـ.
- تطبيق الاختبار على الطلاب عينة البحث فى الفصل الدراسى الأول للعام الدراسى.
أدوات البحث:
• قائمة مهارات الكتابة الوظيفية.
• برنامج تعليمى باستخدام الحاسوب.
• اختبار مهارات الكتابة الوظيفية.
نتائج البحث:
أظهرت نتائج تدريس البرنامج المقترح باستخدام الحاسوب لتنمية مهارات بعض مجالات الكتابة الوظيفية لدى طلاب الصف الأول الثانوى وجود فرق ذو دلالة إحصائية بين متوسطى درجات طلاب المجموعتين التجريبية والضابط فى التطبيق البعدى لاختبار مهارات الكتابة الوظيفية, ويستدل من ذلك أن طلاب المجموعة التجريبية الذين درسوا البرنامج المقترح باستخدام الحاسوب أظهروا تحسناً ملحوظاً فى اكتساب مهارات الكتابة الوظيفية فاق نظراءهم من طلاب المجموعة الضابطة الذين درسوا مقررهم بالطريقة المعتادة
Flexural strengthening of shallow reinforced concrete beams using CFRP plates
No full textThis paper presents experimental data and results on the flexural performance of shallow reinforced concrete beams strengthened with carbon fibre-reinforced polymer (CFRP) plates. A total of four full-scale beams were constructed and tested up to failure. The beams measured 5300 mm long, 500 mm width, and 250 mm deep and were tested in four-point bending over a simply-supported span of 5000 mm. Three beams were strengthened with CFRP plates bonded to the soffit of the beams, while the remaining beam was unstrengthened and served as control. The main variable was the preloading level prior to strengthening. The beams were subjected to three different preloading levels: 0, 40, and 60% of their yield capacity. The strengthened beams were loaded first to the specified load level before strengthening to induce cracks and then unloaded. Thereafter, the beams were strengthened and tested up to failure. The test results indicated that the flexural performance of the strengthened beams was significantly improved. At the service load level, the deflection of the strengthened beams was reduced by about 50% in comparison to that of the unstrengthened beam. Strengthening using CFRP plates was effective in restricting the opening of flexural cracks. The reduction in crack width due to strengthening was more than 68% at the service load level. In addition, the strengthened beams experienced higher ultimate strength than that of the unstrengthened beam. The increase in ultimate strength was more than 140%. Preloading the test beams up to 60% of the yield capacity before strengthening appeared to have marginal effect
Measuring the genetic diversity of Arabian Oryx using microsatellite markers: implication for captive breeding
No full textArabian oryx (Oryx leucoryx) is an endangered antelope that is being protected by captive breeding programs. However, the long term success of these programs mainly depends on the prudent use of molecular information for conservation management. We have used an array of seven microsatellite loci to examine the molecular diversity in a representative population of 24 captive-bred and reintroduced Arabian oryx. The locus-wise mean observed
heterozygosity (0.601) was found to be comparatively higher than the mean expected heterozygosity (0.565). The specimen-wise observed heterozygosity ranged from 0.143 to 1.00 with an average of 0.60 whereas the mean d2 varied from 0.57 to 1023.428 with an
average value of 223.357. The results of Shannon information index (I = 0.898) also indicated a high level of within population genetic diversity. The average gene flow was 0.298, ranging between 0.204 and 0.424 for different loci. In conclusion, the information about the extent of heterozygosity, allelic diversity and inbreeding/ outbreeding depression using microsatellite markers could be of potential relevance for the management of captive breeding programs for the conservation of Arabian Oryx
Interpretation of electrophoretograms of seven microsatellite loci to determine the genetic diversity of the Arabian Oryx
No full textMicrosatellite markers are commonly used for examining population structure, especially inbreeding, outbreeding and gene flow. An array of microsatellite loci, preferably with multiallelic presentation, is preferable for ensuring accurate results. However, artifact peaks or stutters in the electrophoretograms significantly hamper the reliable interpretation of genotypes. We interpreted electrophoretograms of seven microsatellite loci to determine the genetic diversity of the Arabian Oryx
Temporal dynamics of phytoplankton communities in a semi-enclosed mariculture pond and their responses to environmental factors.
No full textVariations in physical-chemical factors, species composition, abundance and biomass of nano- and micro-phytoplankton assemblages, as well as their responses to environmental factors, were investigated over a complete cycle (6 months) in a semi-enclosed shrimp-farming pond near Qingdao, northern China. The aim was to establish the temporal patterns of phytoplankton communities and to evaluate protists as suitable bioindicators to water quality in mariculture systems. A total of 34 taxa with
nine dominant species were identified, belonging to six taxonomic groups (dinoflagellates, diatoms, cryptophyceans, chlorophyceans, euglenophyceans and chrysophyceans). A single peak of protist
abundance occurred in October, mainly due to chlorophyceans, diatoms and chrysophyceans. Two
biomass peaks in July and October were primarily due to dinoflagellates and diatoms. Temporal patterns
of the phytoplankton communities significantly correlated with the changes in nutrients, temperature and
pH, especially phosphate, either alone or in combination with NO3-N and NH3-N. Species diversity,
evenness and richness indices were clearly correlated with water temperature and/or salinity, whereas the
biomass/abundance ratio showed a significant correlation with NO3-N. The results suggest that
phytoplankton are potentially useful bioindicators to water quality in semi-enclosed mariculture systems
Molecular phylogeny of Nothoholosticha (Protozoa, Ciliophora, Urostylida) and systematic relationships of the Holosticha-complex
No full textThe marine ciliate Nothoholosticha is characterized by having a Holosticha-like ciliature pattern but without migratory frontoterminal cirri. However, its systematic position and its relationship to other members of the Holosticha-complex have not yet been resolved. In order to gain deeper insights into these relationships, the small subunit rRNA (SSrRNA) gene and the rRNA internal transcribed spacer and 5.8SrRNA (ITS1–5.8S-ITS2) region of two marine Anteholosticha species, as well as the ITS1–5.8S-ITS2 region of N. fasciola, were sequenced, and molecular trees (BI, ML, NJ and MP trees) were constructed. Although our analyses failed to conclusively resolve the phylogeny of this assemblage, certain conclusions could be drawn. Firstly, Nothoholosticha is a valid genus that is more closely related to Pseudokeronopsis than to other Holosticha-complex genera. Secondly, sequence analyses and phylogenetic trees of several Anteholosticha species revealed
a high molecular diversity, which does not support the monophyly of this genus. Thirdly, the current assignment of certain
well-known genera, e.g. Holosticha, Anteholosticha, Apokeronopsis, Parabirojimia, Psammomitra, Diaxonella,
Metaurostylopsis and Thigmokeronopsis, to the families Bakuellidae (sensu Berger 2006), Urostylidae (sensu Berger 2006)
or Holostichidae (sensu Berger 2006) is challenged by the molecular data presented here. And fourthly, the families
Holostichidae and Pseudokeronopsidae (sensu Lynn 2008) are probably paraphyletic, and their systematic assignments
await further evaluatio
Differential Gene Expression and Physiological Adaptation of Two
No full textGene expression as a valuable stress marker in ecophysiological studies and rapid changes in gene expression in plants in response to stress are important for environmental adaptation. Two Triticum aestivum cultivars [drought sensitive (Sids-1) and drought tolerant (Veery)] were exposed to drought stress interrupted by rehydration period. The differentially expressed gene in drought stressed seedlings
was strongly and rapidly induced in leaves of tolerant wheat (cvVeery) especially after rehydration, whereas induction was delayed and transcripts accumulated to a low level in sensitive one (cv Sids-1). Drought induced alteration in the expression of genes involved in signaling and in oxidative stress responses. A significant variability in drought tolerance was found between the two cultivars: while drought sensitive (Sids-1) oxidative stress indices were significantly increased after 4 days drought stress compared to the control, drought tolerant cultivar (Veery) indices increased after 8 days. After 2 days rehydration, plants exposed to 12 days drought showed better cultivar-dependent behavior, compared to those exposed to drought without rehydration and Veery cultivar showed better drought tolerance than Sids-1. This may be related to their antioxidant activity (smaller IC50 values for both 1,1-diphenyl-2-
picrylhydrazyl and superoxide scavenging), associated with lower leaf MDA accumulation in comparison to sensitive cultivar. Taken together, results suggest that wheat may be interesting for production of antioxidant compounds, and that the cultivar-dependent capacity to induce antioxidative mechanisms in response to drought, may result in a corresponding variability for growth sustainability
Hardware design and implementation of fixed-width standard and truncated 4x4, 6x6, 8x8 and 12x12-bit multipliers using FPGA
No full textThis paper presents Field Programmable Gate Array (FPGA) implementation of standard and truncated multipliers using Very High Speed Integrated Circuit Hardware Description Language (VHDL). Truncated multiplier is a good candidate for digital signal processing (DSP) applications such as finite impulse response (FIR) and discrete cosine transform (DCT). Remarkable reduction in FPGA resources, delay, and power can be achieved using truncated multipliers instead of standard parallel multipliers when the full precision of the standard multiplier is not required. The truncated multipliers show significant improvement as compared to standard multipliers. Results show that the anomaly in Spartan-3 AN average connection and maximum pin delay have been efficiently reduced in Virtex-4 device. © 2010 American Institute of Physics.Middle East Technical University, Curtin University of Technology, LINDO Systems Inc., EUROPT, HINDAW
Enhancement of surface quality using a newly developed technique in turning operations
No full textEvery machining operation leaves characteristic evidence on the machined surface. This evidence takes the form of finely spaced micro irregularities left by the cutting tool. A two-pass technique was introduced for enhancing the surface roughness for different cutting conditions and workpiece materials based on the feed marks (pattern) left by the tool in the machining operation. An important drawback of this technique is that the time taken for its two passes represents twice the time of regular machining. Another drawback is the difficulty of adjusting the tool in the second pass with the appropriate accuracy. For solving these problems, a tool design is provided in this paper to achieve the same results of the two-pass technique in one pass. The objective of this research is to compare this technique using different methods (regular or one pass, two passes, new tool) using different cutting conditions and different workpiece materials. In addition to the surface roughness, straightness and roundness errors are measured for these methods (two passes, new tool) and compared with regular cutting. Improvement of surface roughness was shown as the straightness and roundness errors decrease by using this new technique. In practice, the new tool technique improves the surface roughness, straightness error, and roundness error by more than 58, 65, and 50 per cent respectively at the proposed cutting condition (50m/min cutting speed, 0.2mm/rev feed, and 1mm depth of cut) for all workpiece materials used.King Saud University, Riyadh, Saudi Arabi
Developed models for understanding and predicting the machinability of a hardened martensitic stainless steel
No full textExperimental work was carried out using design of experiment to develop machining models for the dependent variables, tool life, cutting force and surface roughness, when machining a hardened AISI 420 martensitic stainless steel under oblique cutting. Carbide inserts were used as cutting tools in the present investigation. The effect of independent variables including cutting conditions, tool geometry, and hardness levels was investigated. The developed models were tested for the adequacy and validity of the present models. The correlation between dependent and independent variables is presented showing their relations. These models were utilized to find optimum cutting conditions using different optimization functions.King Saud University, Riyadh, Saudi Arabi