A teacher’s use of dynamic digital technology to address students’ misconception about additive strategies for geometric similarity

Research has well documented that students develop a significant misconception associated with the incorrect use of additive strategies when engaging with geometric similarity (GS) tasks. Since dynamic digital technology (DDT) has the potential to support students in addressing this misconception, teachers can exploit the affordances of DDT in the classroom to accomplish it. The aim of this paper is to explore how and why a secondary mathematics teacher uses DDT in the classroom to promote students’ understanding of why additive strategies are inappropriate to use for GS tasks. Drawing on the data collected, through classroom observations and post-lesson teacher interviews, the research findings indicate that the dynamic and visual nature of DDT can be used to help students realise the inappropriateness of the use of additive strategies for GS tasks

Static and vibration analysis of functionally graded beams using refined shear deformation theory

Static and vibration analysis of functionally graded beams using refined shear deformation theory is presented. The developed theory, which does not require shear correction factor, accounts for shear deformation effect and coupling coming from the material anisotropy. Governing equations of motion are derived from the Hamilton's principle. The resulting coupling is referred to as triply coupled axial-flexural response. A two-noded Hermite-cubic element with five degree-of-freedom per node is developed to solve the problem. Numerical results are obtained for functionally graded beams with simply-supported, cantilever-free and clamped-clamped boundary conditions to investigate effects of the power-law exponent and modulus ratio on the displacements, natural frequencies and corresponding mode shapes

The relationship between frontal sinus morphology and skeletal maturation

Background: The aim of this study is to evaluate the relationship between frontal sinus morphology and hand-wrist bone maturation by using postero-anterior (PA) cephalometric radiographs.Materials and methods: The study sample consisted of 220 patients divided into 11 groups based on the hand-wrist radiographs. The right and left maximum height, width and area of the frontal sinus parameters were measured in PA cephalometric radiographs of 220 subjects aged 8–18 years. The hand-wrist skeletal maturation stages were evaluated on the hand-wrist radiographs using the method of Fishman. The Kendall tau-b values were analysed to evaluate the correlation between the hand-wrist skeletal maturation stages and the frontalsinus parameters.Results: The right and left frontal sinus areas and widths were found to be larger in males than in females (p < 0.05). In males, a significant difference was observed in all frontal sinus parameters in different maturation stages (p < 0.001), while a statistically significant correlation was found in females between the left frontal sinus area, right frontal sinus height, right frontal sinus width and different maturation stages (p < 0.05).Conclusions: The relationship between frontal sinus dimensions obtained from PA cephalometric radiographs and hand-wrist maturation stages suggests that frontal sinuses can be used in determining growth and development

Overcoming scarring in the urethra: Challenges for tissue engineering.

Urethral stricture disease is increasingly common occurring in about 1% of males over the age of 55. The stricture tissue is rich in myofibroblasts and multi-nucleated giant cells which are thought to be related to stricture formation and collagen synthesis. An increase in collagen is associated with the loss of the normal vasculature of the normal urethra. The actual incidence differs based on worldwide populations, geography, and income. The stricture aetiology, location, length and patient's age and comorbidity are important in deciding the course of treatment. In this review we aim to summarise the existing knowledge of the aetiology of urethral strictures, review current treatment regimens, and present the challenges of using tissue-engineered buccal mucosa (TEBM) to repair scarring of the urethra. In asking this question we are also mindful that recurrent fibrosis occurs in other tissues-how can we learn from these other pathologies

The effects of different irrigation regimes on yield and silage quality of corn under semi-arid conditions

The aim of this study was to evaluate the effects of different quantities of drip irrigation water on the corn yield and silage quality under semi-arid conditions. The seasonal evapotranspiration (ETc) for the different irrigation regimes varied from 434 to 947 mm in 2004 and from 468 to 1003 mm in 2005 for total irrigation periods of 108 and 113 days, respectively. Combining data from both years, the relative evapotranspiration deficit (1−ETa/ETm) for different regimes was 19 to 54% in corn compared to the maximum seasonal ETc when water was not limited in the (I100) regime. During the course of both years, irrigation had an apparent effect on the total fresh silage yield (FSY), with yields increasing steadily from water stress to fully irrigated conditions, while silage yields increased linearly with the total depth of irrigation water applied between planting and harvest. Combining data from both years showed that the FSY was 35.0, 53.6, 83.3 and 88.9 t ha-1 for I25, I50, I75 and I100, respectively. Moreover, the largest FSY recorded amongst these experiments at maximum seasonal yield in single treatment was 89.1 t ha-1 in 2004 and 88.7 t ha-1 in 2005. The water content decreased considerably in all but FSY, while the dry matters yield (DMY), organic matter (OM), acid detergent fiber yield (ADFY) and in vitro dry matter digestibility (IVDMD) increased. Furthermore, the study substantiated that the highest yield and silage quality were obtained at the full (I100) irrigation regime.Key words: Silage, deficit irrigation, yield, silage quality

Mitral regurgitation:when to intervene? A historical perspective

Although mitral regurgitation (MR) is the most common valvular heart disease, it should be regarded as a complex multifactorial disease that involves multiple entities. Optimal medical therapy alone does not hinder the progression of the disease, and in the 1980s it was already recognised that corrective surgery is indicated if MR is severe and patients are symptomatic (except for those with the most severe left ventricle dysfunction). Later on, asymptomatic patients with deterioration of the left ventricular ejection fraction were also operated on to avoid irreversible left ventricular dysfunction, heart failure and eventually death. However, a major drawback remains the fact that a significant group of patients is considered to have a high perioperative risk due to their advanced age or severe comorbidities. Since less invasive, percutaneous interventions have been developed and recently thoroughly investigated in the MITRA-FR and the COAPT studies, the type of intervention and also the timing have become more crucial. In this critical review of the literature, we describe what we should have learned from the past and which (haemodynamic) parameters can best predict the outcome in patients with MR

Ferroelectric Based Photonic Crystal Cavity by Liquid Crystal Infiltration

Cataloged from PDF version of article.A novel type of two-dimensional photonic crystal is investigated for it optical properties as a core-shell-type ferroelectric nanorod infiltrated with nematic liquid crystals. Using the plane wave expansion method and finite-difference time-domain method, the photonic crystal structure, which is composed of a photonic crystal in a core-shell-type ferroelectric nanorod, is designed for the square lattice and the hexagonal lattice. It has been used 5CB as a photonic crystal core, and LiNbO3 as a ferroelectric material. The photonic crystal with a core-shell-type LiNbO3 nanorod infiltrated with nematic liquid crystals is compared with the photonic crystal with solid LiNbO3 rods and the photonic crystal with hollow LiNbO3 rods

Electron Spectroscopy and the Electronic Structure of KNbO3: First Principle Calculations

Cataloged from PDF version of article.The electronic structures of KNbO(3)were calculated within the density functional theory, and their evolution was analyzed as the crystal-field symmetry changes from cubic to rhombohedral via tetragonal phase. We carried out electron-energy loss spectroscopy experiments by using synchrotron radiation and compared the results with the theoretical spectra calculated within Density Functional Theory. The dominant role of the NbO(6)octahedra in the formation of the energy spectra of KNbO(3)compound was demonstrated. The anomalous behavior of plasmons in ferroelectrics was exhibited by the function representing the characteristic energy loss in the region of phase transition

Exact Solutions of the Duffin Kemmer Petiau Equation for the Deformed Hulthen Potential

Using the Nikiforov Uvarov method, an application of the relativistic Duffin Kemmer Petiau equation in the presence of a deformed Hulthen potential is presented for spin zero particles. We derived the first order coupled differential radial equations which enable the energy eigenvalues as well as the full wavefunctions to be evaluated by using of the Nikiforov Uvarov method that can be written in terms of the hypergeometric polynomials.Comment: 8 pages. submitted to Physica Script

KINETIC AND KINEMATIC ANALYSIS OF RECURVE ARCHERY SHOOTING TECHNIQUE

The study investigated shooting techniques of the archers with kinetic and kinematic methods. Twenty-seven archers of different skill levels have been involved into the current study to investigate both muscular activation strategies of nine muscles and some kinematic data on drawing hand side. A statistical significant difference (p0.05) in the time-dependent exchange values of the angle of the joints, a difference was detected in the graphical sense. Elite archers use distal muscles less but proximal and axial muscles more, and mid-level and novice archers use distal muscles more to pull the bowstring. This was interpreted to be the most important factor affecting the horizontal oscillation (lateral diflection) of bowstring