Formation of the three-dimensional geometry of the red blood cell membrane

Red blood cells (RBCs) are nonnucleated liquid capsules, enclosed in deformable viscoelastic membranes with complex three dimensional geometrical structures. Generally, RBC membranes are highly incompressible and resistant to areal changes. However, RBC membranes show a planar shear deformation and out of plane bending deformation. The behaviour of RBCs in blood vessels is investigated using numerical models. All the characteristics of RBC membranes should be addressed to develop a more accurate and stable model. This article presents an effective methodology to model the three dimensional geometry of the RBC membrane with the aid of commercial software COMSOL Multiphysics 4.2a and Fortran programming. Initially, a mesh is generated for a sphere using the COMSOL Multiphysics software to represent the RBC membrane. The elastic energy of the membrane is considered to determine a stable membrane shape. Then, the actual biconcave shape of the membrane is obtained based on the principle of virtual work, when the total energy is minimised. The geometry of the RBC membrane could be used with meshfree particle methods to simulate motion and deformation of RBCs in micro-capillaries

Understanding preservice teachers’ development of pedagogical knowledge practices when co-teaching primary science to peers

Preservice teachers articulate the need for more teaching experiences for developing their practices, however, extending beyond existing school arrangements may present difficulties. Thus, it is important to understand preservice teachers’ development of pedagogical knowledge practices when in the university setting. This mixed-method study investigated 48 second-year preservice teachers’ development of pedagogical knowledge practices as a result of co-teaching primary science to peers. Data were collected through a survey, video-recorded lessons, extended written responses and researcher observations. The study showed how these preservice teachers demonstrated 9 of 11 pedagogical knowledge practices within the co-teaching arrangement. However, research is needed to determine the level of development on each pedagogical knowledge practice and how these practices can be transferred into authentic primary classroom settings.

Mentors’ and mentees’ views about desirable attributes and practices for preservice teachers

Universities provide preservice teachers (mentees) with directions on how to engage within their school placements, yet mentees have ongoing concerns about how to interact with their mentors. What are desirable attributes and practices for preservice teachers in their roles as mentees? This qualitative study gathers data from primary and secondary Australian teachers (n=25) through extended response questionnaire and audio-recorded focus group discussions, and preservice teachers (n=10) using audio-recorded interviews at the conclusion of their four-week practicum. Findings indicated that mentors had clear views on desirable attributes (e.g., enthusiasm, commitment, resilience) and practices (e.g., planning, preparation, building a teaching repertoire) for mentees; whereas mentees had varying views on identifying such attributes and practices and did not refer to: content knowledge, differentiation, and knowing school and university policies. This showed that mentees need more guidance for focusing on specific attributes and practices to benefit the mentoring relationship and their teaching development.

Editorial - Assessment of EAL/D learners : the validity of teachers' professional judgements

Assessment is a recurring theme in this issue of TESOL in Context. It is the focus of a themed section; addressed in some of the award-winning thesis research we feature; and one of several topics in an article on EFL teacher preparation in an Australian university. In the first section of the issue we are pleased to publish précis of the theses produced by the joint winners of the Penny McKay Memorial Award for Best Thesis in Language Education. Penny was a major figure in the development of EAL/D education in Australia (see Dooley & Moore, 2009). Her work is remembered and continued through an Award established by the Australian Council of TESOL Associations (ACTA) and the Applied Linguistics Association of Australia (ALAA). The award recognises doctoral research which makes an outstanding contribution to second/additional language education in Australian schools (http://www.tesol.org.au/About-ACTA/PENNY-MCKAY-MEMORIAL-FUND)...

Structuring representations of continuous data through investigations in grade 1

The study of data modelling with elementary students involves the analysis of a developmental process beginning with children’s investigations of meaningful contexts: visualising, structuring, and representing data and displaying data in simple graphs (English, 2012; Lehrer & Schauble, 2005; Makar, Bakker, & Ben-Zvi, 2011). A 3-year longitudinal study investigated young children’s data modelling, integrating mathematical and scientific investigations. One aspect of this study involved a researcher-led teaching experiment with 21 mathematically able Grade 1 students. The study aimed to describe explicit developmental features of students’ representations of continuous data...

Bacterial adherence and biofilm formation on medical implants : a review

Biofilms are a complex group of microbial cells that adhere to the exopolysaccharide matrix present on the surface of medical devices. Biofilm-associated infections in the medical devices pose a serious problem to the public health and adversely affect the function of the device. Medical implants used in oral and orthopedic surgery are fabricated using alloys such as stainless steel and titanium. The biological behavior, such as osseointegration and its antibacterial activity, essentially depends on both the chemical composition and the morphology of the surface of the device. Surface treatment of medical implants by various physical and chemical techniques are attempted in order to improve their surface properties so as to facilitate bio-integration and prevent bacterial adhesion. The potential source of infection of the surrounding tissue and antimicrobial strategies are from bacteria adherent to or in a biofilm on the implant which should prevent both biofilm formation and tissue colonization. This article provides an overview of bacterial biofilm formation and methods adopted for the inhibition of bacterial adhesion on medical implants

Decision making in social neurobiological systems modeled as transitions in dynamic pattern formation

Extant models of decision making in social neurobiological systems have typically explained task dynamics as characterized by transitions between two attractors. In this paper, we model a three-attractor task exemplified in a team sport context. The model showed that an attacker–defender dyadic system can be described by the angle x between a vector connecting the participants and the try line. This variable was proposed as an order parameter of the system and could be dynamically expressed by integrating a potential function. Empirical evidence has revealed that this kind of system has three stable attractors, with a potential function of the form V(x)=−k1x+k2ax2/2−bx4/4+x6/6, where k1 and k2 are two control parameters. Random fluctuations were also observed in system behavior, modeled as white noise εt, leading to the motion equation dx/dt = −dV/dx+Q0.5εt, where Q is the noise variance. The model successfully mirrored the behavioral dynamics of agents in a social neurobiological system, exemplified by interactions of players in a team sport.

Changing views of culture, learning, teaching, and knowledge : Fiji in-service primary teachers

This paper explores in-service primary teachers' views and beliefs about culture, learning, teaching and knowledge. Fifty Bachelor of Education in-service primary teachers at a university in Fiji participated in the study. The analysis reveals a mix of old and new beliefs about culture, learning teaching and knowledge. The influence of globalization of technology is a contributing factor towards changing views. To keep the indigenous epistemologies alive and valued like the Western epistemologies, more effort is needed to integrate these in formal education. This has implications for the future professional preparation of pre-service and in-service teachers.

Workplace Learning in Physical Education : Emerging Teachers’ Stories from the Staffroom and Beyond

Pre-service and beginning teachers have to negotiate an unfamiliar and often challenging working environment, in both teaching spaces and staff spaces. Workplace Learning in Physical Education explores the workplace of teaching as a site of professional learning. Using stories and narratives from the experiences of pre-service and beginning teachers, the book takes a closer look at how professional knowledge is developed by investigating the notions of ‘professional’ and ‘workplace learning’ by drawing on data from a five year project. The book also critically examines the literature associated with, and the rhetoric that surrounds ‘the practicum’, ‘fieldwork’ ‘school experience’ and the ‘induction year’. The book is structured around five significant dimensions of workplace learning: Social tasks of teaching and learning to teach Performance, practice and praxis Identity, subjectivities and the profession/al Space and place for, and of, learning Micropolitics As well as identifying important implications for policy, practice and research methodology in physical education and teacher education, the book also shows how research can be a powerful medium for the communication of good practice. This is an important book for all students, pre-service and beginning teachers working in physical education, for academics researching teacher workspaces, and for anybody with an interest in the wider themes of teacher education, professional practice and professional learning in the workplace.

Preparation of macroporous methacrylate monolithic material with convective flow properties for bioseparation : Investigating the kinetics of pore formation and hydrodynamic performance

The preparation of macroporous methacrylate monolithic material with controlled pore structures can be carried out in an unstirred mould through careful and precise control of the polymerisation kinetics and parameters. Contemporary synthesis conditions of methacrylate monolithic polymers are based on existing polymerisation schemes without an in-depth understanding of the dynamics of pore structure and formation. This leads to poor performance in polymer usage thereby affecting final product recovery and purity, retention time, productivity and process economics. The unique porosity of methacrylate monolithic polymer which propels its usage in many industrial applications can be controlled easily during its preparation. Control of the kinetics of the overall process through changes in reaction time, temperature and overall composition such as cross-linker and initiator contents allow the fine tuning of the macroporous structure and provide an understanding of the mechanism of pore formation within the unstirred mould. The significant effect of temperature of the reaction kinetics serves as an effectual means to control and optimise the pore structure and allows the preparation of polymers with different pore size distributions from the same composition of the polymerisation mixture. Increasing the concentration of the cross-linking monomer affects the composition of the final monoliths and also decreases the average pore size as a result of pre-mature formation of highly cross-linked globules with a reduced propensity to coalesce. The choice and concentration of porogen solvent is also imperative. Different porogens and porogen mixtures present different pore structure output. Example, larger pores are obtained in a poor solvent due to early phase separation.