Basic Education Teachers' Proficiency of Skills Required for Teaching Mathematical Concepts

This study aimed to determine basic education teachers’ proficiency of skills required for teaching mathematical concepts. The study sample consisted of (115) male teachers and (113) female teachers, the study results showed that the level of basic education teachers' proficiency of skills required for teaching mathematical concepts was average ranging from (2:27) to (4:13), while the overall average level of proficiency of these skills was ( 3:04).The results showed statistically significant differences in the level of basic education teachers' proficiency of skills required for teaching mathematical concepts based on some variables (educational stage, educational administration, gender, years of experience, grade, teaching load, and employment type), in favor of,  female teachers, those who have longer years of experience, the elementary grades (fourth, fifth and sixth),  the least teaching load, temporary teachers, where there are no significant differences with regard to teachers' proficiency skills required for teaching mathematical concepts that can be attributed to the variable of educational administration

Polynomial Models to Study and Present Within-Tree Variation of Wood Properties

A method is presented for obtaining information on within-tree variation for wood properties. The polynomial models resulting from this study provide a technique for statistical analysis and for plotting within-tree variation patterns of fiber, vessel, and ray percentages as well as ring widths. With this method, it is possible to examine the oblique, horizontal, and vertical variation patterns of different wood properties, both statistically and graphically; hence, statistical inference can conveniently be made on within-tree patterns of variation. This can provide not only information of value in tree improvement work, but also a better understanding of the variability of wood

Technetium-99m Sestamibi Scintigraphy Pattern in Patients with Secondary Hyperparathyroidism

complications of end stage renal disease (ESRD). We aimed in this investigation to explore the role of Technetium-99m sestamibi (99mTc MIBI) scintigraphy in the pre-operative assessment of refractory hyperparathyroidism in hemodialysis (HD) patients. Methods: Dual-phase 99mTc MIBI parathyroid scintigraphy was performed for 23 patients with ESRD who have persistent intact parathyroid hormone (iPTH) levels exceeding 300 pg/ml. Based on scintigraphy results, 13 patients underwent neck exploration during which only glands with positive scintigraphy findings were removed. Results: Among the six patients who had iPTH levels < 800 pg/ml, only one patient had positive scintigraphy findings (16.7%). Among the 17 patients who had iPTH levels ≥ 800 pg/ml, 16 patients had positive scintigraphy findings (94.1%). 99mTc MIBI scan detected 23 positive sites of focal trace uptake in those 17 patients. Partial parathyroidectomy was performed for 13 patients, removing in total 19 glands, while four patients declined surgery. On histological examination, 12 glands showed diffuse hyperplasia, four glands showed nodular hyperplasia and three glands revealed parathyroid adenoma. The three glands with parathyroid adenoma were correctly identified prior to surgery by 99mTc MIBI scintigraphy. The long-term outcomes of these patients are now being monitored. Conclusion: ESRD patients with iPTH level ≥ 800 pg/ml are more likely to have positive sites of focal tracer uptake on MIBI scan than patients with lower iPTH levels. Dual-phase 99mTc MIBI scintigraphy has the ability to correctly identify parathyroid adenoma prior to surgical exploration in these patients. Keywords: Hyperparathyroidism, parathyroid adenoma, parathyroid hyperplasia, scintigraphy, 99mTc sestamib

Hydration Characteristics of Limestone Filled Cement Pastes

The physico-mechanical properties of hardened limestone-filled cement pastes were studied. Five filled-cements were prepared from 0, 5, 10, 15 and 20 wt. % of limestone and OPC. The water of consistency of filled-cement pastes was 0.275, 0.275, 0.275, 0.272, and 0.270, respectively. The pastes are moulded into one inch cubic moulds and left within the moulds at 100% relative humidity for 24 h, then demoulded and cured under tap water for 3, 7, 28, and 90 days. At each hydration time, the combined water, bulk density, total porosity and compressive strength of the hardened filled-cement pastes were determined. Some selected filled-cement pastes were investigated using differential thermal analysis (DTA) and scanning electron microscope (SEM) Techniques. Addition of limestone to Portland cement causes an increase of hydration at early ages inducing a high early strength, but it can reduce the later strength due to the dilution effect. The results indicate that the addition of limestone up to 5 wt. % improves the physico-mechanical properties of ordinary Portland cement which acts as a nucleating agent and accelerates the hydration of filled cement pastes. The addition of 5 wt. % limestone can be used in the production of portland cement according to the international specifications. On the other side, the addition of 10-20 wt. % limestone can be used in the production of blended or mixed cements

Some Structural Changes Observed in the Transformation of Wood into Charcoal1

On the basis of measurements of microtomed cubes of white oak and on resultant charcoal, dimensional changes occurring on the conversion of wood into charcoal are: tangential, -25.68%, radial, -15.45%, and longitudinal, -11.43%. Light microscopic examination of charcoal reveals residues of combustion present in cell cavities. Electron microscopic examination indicates that the original fibrillar arrangement of the cell wall has been replaced with a smooth, "amorphous-appearing" wall structure

Windbreak-Grown Casuarina and Eucalyptus Trees for Unbleached Kraft Pulp

A laboratory-scale evaluation was conducted of juvenile windbreak-grown Casuarina and Eucalyptus trees for kraft pulp production. Test results of unscreened pulp yields, pulp chemical analyses, and handsheet physical properties indicated that windbreak-grown materials are suitable for unbleached kraft pulp. Casuarina gave the best pulp yield and had higher tear strength than Eucalyptus, but both species were superior to kraft pulps from agricultural raw materials such as rice straw and Thymelia, which are currently used in Egypt. For both species, the best kraft pulping schedule tested was a 4:1 liquor-to-wood ratio with 20% active alkali with additional conditions constant. Scanning electron micrographs of handsheets helped explain the observed differences in physical properties between the two species. Mixing of Casuarina and Eucalyptus raw material prior to pulping shows promise for unbleached kraft pulp production

Effect of type of mixing water and sand on the physico–mechanical properties of magnesia cement masonry units

AbstractThis study has been conducted to investigate the influences of sand addition and mixing waters with different ratios on the physico-mechanical properties of magnesium oxychloride cement (MOC) masonry units. Three mixtures (M, MI and MII) were prepared to make magnesium oxychloride cement from the sand dunes as a filler material with some different additives. The mixture (M) was prepared by seawater instead of tap water in the mixing process, other mixtures (MI & MII) used drinking water. The physico-mechanical properties were studied in means of determination of bulk density, water absorption and compressive strength of the hardened MOC specimens cured in air at the lab ambient conditions for 3, 7, and 28days. It was recognized that the compressive strengths decreased with the increase of sand dunes content. The specimens of the all cured mixtures fulfilled superior properties compared with the required limits for concrete and limestone masonry units of a heavy density type. Also, it was found that using of the seawater leads to increase the physico-mechanical properties of the MOC specimens and can be used as mixing water in the manufacture of masonry units instead of the traditional drink water after ensuring of the other demanded governing properties

Mathematical Description of the Change in Properties of Casuarina Wood Upon Exposure to Gamma Radiation. 1. Changes in the Compressive and Tensile Strength

Casuarina cunninghamiana specimens were exposed to gamma-radiation doses ranging from 104 to 108 rad and tested in compression and tension parallel to grain. The percentage values of the irradiated specimens relative to that of the matched control (Y) were determined. The relationship between (Y) and log gamma radiation dose (X) was represented mathematically by the equation: Y = aXbcx. This equation described the change in compressive and tensile strength very well as was detected from the high correlation coefficients. Generally these properties increased slightly at low levels of radiation, reached a maximum, then decreased gradually thereafter. The reduction in tensile strength was more pronounced than in compressive strength.The threshold dose, i.e., the dose beyond which the properties began to decrease, was calculated. This dose ranged from 3.69 x 106 to 3.76 x 106 rad for compressive strength properties and from 1.51 x 106 to 1.70 x 106 rad for tensile strength properties. This indicated that irradiated casuarina wood had a greater resistance to compression than to tension

A longitudinal study of bovine viral diarrhea virus in a semi-closed management dairy cattle herd, 2020–2022

IntroductionBovine viral diarrhea virus (BVDV) brings great economic loss to the cattle industry worldwide. Developing a control/prevention strategy requires the prior assessment of certain epidemiological parameters. To determine the BVD incidence rate and associated risk factors, a dairy cattle herd in the eastern region of Saudi Arabia was monitored between 2020 and 2022.MethodsNasal swabs (n = 190), rectal swabs (n = 190), and sera (n = 190) were collected from 79 cows in this herd. Collected sera and swabs were tested using the commercially available ELISAs for the BVDV antibodies and antigens, respectively. Collected sera were also tested for the presence of BVDV nucleic acids using commercial real-time RT-PCR kits.Results and discussionOur data show BVDV seroprevalence (18.8%, 15%, and 8.2%) in the tested animals in 2020–2022, respectively. None of the collected nasal swabs, rectal swabs, or sera tested positive for the BVDV antigen, whereas 10.1%, 10%, and 18.1% of the tested sera were positive for BVDV nucleic acid in 2020–2022, respectively. The incidence rate was estimated at 0.02446 new cases/year despite the detection of BVDV in seronegative animals on single or two occasions at ≥6-month intervals. Young calves and bulls remained apparently unexposed to BVDV despite their presence with BVDV-infected females, with no significant physical separation. Both seropositivity and nucleic acid detectability showed significant positive and negative correlations, respectively, with reproductive performance. Collectively, the present study provides useful clues about the transmissibility of BVDV in the presence of possibly persistently infected animals. To the best of our knowledge, this is the first longitudinal study of BVDV in the Eastern Region of Saudi Arabia. Further detailed characterization of the circulating BVDVs is encouraged