964 research outputs found
Thermal ecology and activity of the sand fish lizard, scincus mitranus (Scincidae) in Central Arabia
No full textAuthors: Al-Johany Awadh M.& Al-Sadoon, Mohamed K. From Department of Zoology,
Author: Al-Farraj Saud A., From Department of Biology
Riyadh, Teachers' College, King Saud University, P.O. Box 4341,
Riyadh 11491. Saudi ArabiaThermal ecology and activity of Scincus mitranus was investigated during winter and summer seasons. Emergence and basking behavior and seasonal activity were studied and analyzed. The lizard was active throughout the year except during cold spells of winter. However, it was found that during winter, daily activity was unimodal, which contrasted with the bimodal pattern during summer. Selected body temperature, critical minimum and maximum were studied and determined in the laboratory
Effect of short-term heat stress on the immune function of chickens: a review
No full textPrevious studies indicated that exposure to heat stress for a short duration often adversely affected humoral and/or cell-mediated immunity in chickens. This effect was attributed to a rise in blood corticosteroids, although other complex mechanisms involving nervous, endocrine and immunological interactions were also implicated. It is generally conceded that the suppressive effect of heat on antibody production was more likely to occur during pre-induction and early induction phases of antibody synthesis, and that heat stress suppressed lymphocyte and phagocytic cell functions. On the other hand, short-term heat stress was sometimes shown to either exert a non-significant effect on the immune function of chickens, or, conversely, act as a stimulant, increasing both antibody production and cell-mediated responses in heat treated birds. This controversy reflects the complexity of mechanisms affecting the establishment of immune responses under different conditions of thermal stress. Studies were also reported indicating that the immune functions of heat stressed birds might be influenced by their breed and sex, while both heat stress and immunization might influence the metabolic profile of birds. .Corresponding Author:
Dr. Saud Ibrahim Al-Mufarrej,
Associate Professor of Poultry Disease and Immunology, Department of Animal Production
College of Food Science and Agriculture, King Saud University, PO Box 2460, Riyadh 11451, Saudi Arabia. Email: [email protected]
Factors affecting protein extractability of defatted karkade (hibiscus sabdariffa)seed flour
No full textFood Science Department, College of Agriculture, King Saud University, Riyadh, Saudi ArabiaKarkade seed flour was defatted by two different methods. The cold method was better than the hot method in terms of protein extractability. Protein extractability was studied under various condi-tions of pH (2-12), time (30, 45, 60min), salt type (CaCI2, NaCl) , solvent: flourratio (10:.1,15:1,20:1) and salt concentrations (0.2, 0.4, 0.6, 0.8 and 1 M). Results showed that protein extractability was dependent on pH, type of salt and salt concentration. Higher yield was obtained with CaCI2 than NaCI. Highest pro-tein yield was obtained at pH 11 and at 0.4 M CaCl2
Synthesis and spectroscopic properties of some pyrimido[4,5-b]quinoliiie derivatives
No full textAuthor: 1, Women Students Medical Studies & Sciences Sections, Chemistry Department,
College of Science, King Saud University
P.O. Box 22452, Riyadh 11495.
Author: 3, From Chemistry Department, College of Science, King Saud University
P.O. Box 2455, Riyadh 11451.Several substituted pyrimido[4,5-b]quinoline were synthesized from the intermediates: 2-chloro-3-quinolinecarbonitrile (1d), 2-amino-3-quinolinecarbonitrile (1h) and 2-oxo-3-quinolinecarboxylic acid (1g), via cyclization with urea, thiourea, guanidine, formamide and acetic anhydride. Structural elucidation of the prepared quinolines and pyrimido[4,5-b]quinolines was mainly based on the spectroscopic methods, and in particular, MS and NMR spectr
Life transfigured into Art: a critical review of the Rock and Other poems
No full textThe Rock and Other Poems is a richly resourceful and highly sophisticated book of poetry that contains 46 short lyrical poems arranged in five sections entitled: “Palestinian”, “From Japan”, “Of Beauty”, “Meditations” and “Occasional.” The author is a most distinguished Saudi scholar and academician of King Saud University (now
retired), Professor Ezzat Khattab, a specialist in English poetry. The poems reflect the scholarly interests of its author as they materialize in a nice blending of several traditions of English poetr
Tahlil al-Akhto' al-Imlaiyah fi al-Hamzah Lada Thullab Ma'had al-Lughawiyat al-'Arobiyah Bi Jami'ati al-Malik Sa'ud
No full textThis study aimed to know the spelling errors in Hamza among students of the Institute of Arabic Linguistics at King Saud University. The sample of the study consisted of (23) students represented in three levels: (beginner, intermediate and advanced) .The study relied on the descriptive analytical research methodology. To collect information from the study sample, the validity and reliability of the tool was verified by presenting it to a group of arbitrators with competence in the field. The results of the study indicated that there are statistically significant differences between the three levels. (37%), and The percentage of errors in writing Hamza in the middle of the word reached (55%), and the percentage of errors in writing Hamza in the back of the word (08%). As for the percentage of mistakes of middle level students in the writing of extreme Hamza (25.4%), and the percentage of mistakes in writing Hamza in the center of the word (57.3%), and the percentage of errors in the writing of extreme Hamza reached (17.3%). As for the advanced level students, the percentage of their mistakes in writing the Hamza at the beginning of the word (33.3%), and the percentage of errors in writing in the middle of the word (60%), and errors related to the writing of the Hamza at the end of the word (06.7%), as a result The study concluded with a set of recommendations in the light of the results shown
Intersection and minimax inequality with a generalized coercivity in h-spaces
No full textWe define a generalized coercivity type condition for correspondence defined on atopological vector space endowed with a generalized convex structure. An extension of the Fan’smatching theorem is obtained and used to prove results on coincidence, fixed point and minimaxinequality with a weakned compactness condition.Corresponding Author:
Dr. Souhail Chebbi, Associate Professor, Department of Mathematics, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia. Email: [email protected]
Patient satisfaction with the dental services provided by the dental college of King Saud University
No full textThe objective of this study was to measure patients' satisfaction with services and dental care provided by the College of Dentistry of
King Saud University. Six hundred and fifty copies of a designed questionnaire were distributed in both Malaz (MUC) and Darraiya
(DUC) campuses of the Dental College. The questionnaires were distributed, for two months, to regular patients by the receptionist
when the patients arrived for their appointments. Twenty-three items concerning personal data, satisfaction with facilities, services,
and perception of care received were included in the survey. Results: 1. The most common reason (75%) for wanting to be a patient at
the Dental College was the perceived availability of up-to-date care. 2. Sixty-two percent of the patients indicated that friends or
neighbors advised them to go to the Dental College. 3. Patients were significantly dissatisfied with some items such as parking areas
facilities, elevators, and getting appointments by phone. 4. Eighty-four percent responded positively to items concerning treatment.
For the length of the appointments only 26% responded positively. 5. Ninety-eight percent indicated that they would recommend the
Dental College to others seeking dental care. In conclusion, the results of this questionnaire indicated that the majority of the
patients who responded were satisfied with the facilities, services and treatment received at the Dental College clinics of King Saud
University.Corresponding Author:
Dr. Wedad Y. Awliya
Assistant Professor, Department of Restorative Dental Sciences and Malaz Clinic Director
College of Dentistry, King Saud University
P.O. Box 5967, Riyadh 11432, Saudi Arabia.
Email: [email protected]
Effect of soil properties on sorption of cadmium in selected soil orders
No full textThis study was conducted to evaluate the effect of soil chemical and physical properties on Cd
sorption by different soils classified as Entisols, Molisols, Aridisols, and Andisols. Sorption isotherms
were obtained using batch experiments in which 25 ml of solution containing a total of 0.8, 1.6, 3.2, 6.4,
and 12.8 ppm of Cd2+ were added to 0.5 g soil samples. Cadmium sorption was also evaluated at a
constant [Cd]T of 12.8 ppm in four pH levels (5, 6, 7, and 8). The results indicate that, in all the soils
used, the Cd sorption is best described by the Freundlich sorption isotherm. The maximum soil sorption
capacity b (mg g-1) was significantly correlated with inorganic poorly crystalline iron (Feo- Fep), and the
total oxalate extractable iron (Feo) at the probability level of (p < 0.05). Distribution coefficient (kd)
values of Cd in soils were significantly correlated to silt %, Feo- Fep, Feo at (p < 0.01); and Fed at (p <
0.05). For all investigated soils, the sorbed amounts of Cd increased with increasing pH. A small change
in pH can cause a dramatic change in the sorption capacity of the soil, especially at soil pH values
below 6.Corresponding author
Dr. Saud S. AL-Oud,
Department of Soil Water Science
College of Agriculture & Vet. Medicine
King Saud University, AlQassim Branch
P.O. Box 2460, Riyadh 11451, Kingdom of Saudi Arabia. Email: [email protected]
Casing design considerations for horizontal wells
No full textHorizontal Drilling is now a well established technique with growing popularity for exploiting a number of reservoirs which would otherwise be noncommercial. However, a horizontal well requires a substantial engineering work compared to conventional directional drilling. Significant advances in drilling technology have made it possible to drill horizontally in almost any situation by using very specialized tools. But some inherent weaknesses to this technique still exist, like casing design. Most of the reported horizontal wells are completed with open hole or slotted linear. This type of completion is simple and inexpensive, but may not furnish enough support to the walls of the well to allow for long well life. This paper discusses casing design considerations for horizontal wells. It addresses the type and nature of loads applied on casing strings set in horizontal wells; examples of these loads are torque and drag, formation subsidence, effect of perforations, and bending loads. A design method for casing string under loads that prevail in horizontal wells is also included. The proposed design method shows that the horizontal section needs high collapse resistance pipe or thick-wall pipe to avoid casing failure due to non-conventional loads that prevails in horizontal wells
- …
