Temporal Trends of Malondialdehyde in Stored Human Plasma

Malondialdehyde (MDA) is widely used as oxidative stress biomarker in biomedical research. Plasma is stored in deep freezers generally till analysis. Effect of such storage on MDA values, which may be variable and prolong, was incidentally observed in the ongoing study which is to estimate oxidative stress with oral iron. Plasma from blood samples of pregnant women (20–30 years age) in third trimester of singleton pregnancy (n = 139), consuming oral iron tablets was stored at −20 °C with intention of MDA estimation, as soon as possible. However logistic problems led this storage for prolonged and variable period (1–708 days). When values of MDA estimated using “Ohkawa” 79 method and readings were plotted against time to check the temporal effect, it showed a hyperbolic curve. Standard deviation (SD) was lowest when samples were tested within 3 weeks time. The samples analyzed within 3 weeks had mean ± SD value of 31.59 ± 26.11 μmol/L, while 123.7 ± 93.97 and 366.5 ± 189.8 μmol/L for samples stored for 1–3 and 4 months to 1 year respectively. Mean ± SD were 539.9 ± 196.8 in the samples store for more than a year. Rate of change in values was also lowest (0.0433 μmol/L/day) in the samples tested within first 3 weeks, which rose to 1.2 μmol/L/day during 3 month’s storage. This rate peaked at storage of 120 days (1.87 μmol/L/day) and fell to 0.502 μmol/L/day in the second year of storage. It is concluded that at −20 °C, only 3 weeks of storage time should be considered valid for fairly acceptable stability in MDA values.     

Pre-service primary teachers’ conceptions of creativity in mathematics

Teachers in the UK and elsewhere are now expected to foster creativity in young children (NACCCE, 1999; Ofsted, 2003; DfES, 2003; DfES/DCMS, 2006). Creativity, however, is more often associated with the arts than with mathematics. The aim of the study was to explore and document pre-service (in the UK, pre-service teachers are referred to as ‘trainee’ teachers) primary teachers’ conceptions of creativity in mathematics teaching in the UK. A questionnaire probed their conceptions early in their course, and these were supplemented with data from semi-structured interviews. Analysis of the responses indicated that pre-service teachers’ conceptions were narrow, predominantly associated with the use of resources and technology and bound up with the idea of ‘teaching creatively’ rather than ‘teaching for creativity’. Conceptions became less narrow as pre-service teachers were preparing to enter schools as newly qualified, but they still had difficulty in identifying ways of encouraging and assessing creativity in the classroom. This difficulty suggests that conceptions of creativity need to be addressed and developed directly during pre-service education if teachers are to meet the expectations of government as set out in the above documents.     

Estimating the Effects of Students’ Social Networks: Does Attending a Norm-Enforcing School Pay Off?

In an attempt to forge tighter social relations, small school reformers advocate school designs intended to create smaller, more trusting, and more collaborative settings. These efforts to enhance students’ social capital in the form of social closure are ultimately tied to improving academic outcomes. Using data derived from ELS: 2002, this study employs propensity scores in the context of multilevel models to estimate the effects of a specific school-level variant of social closure, referred to as a norm-enforcing school, on students’ mathematics achievement. Results estimate that attending a norm-enforcing school has no effect on 12th-grade mathematics achievement. This result questions the presumed benefits of social capital and its emphasis on norm-enforcement and social control. Policy implications are discussed in light of contemporary urban school reform initiatives that focus on reductions in school size.     

Becoming “Effective” Citizens? Change-Oriented Service in a Teacher Education Program

The authors investigated the impact of 22 pre-service teachers’ participation in a change-oriented service-learning project on their conceptions of citizenship as civic actors and civic educators. The goal of this project was to push students toward adopting more critically conscious and activist conceptions of citizenship as aligned with the needs of a democratic society. Using Eyler and Giles’ (1999) typology of effective citizenship as an analytic framework, we describe how students’ participation in this project led to demonstrated growth along all five dimensions of effective citizenship. Yet, analysis revealed that, despite the project’s change-orientation, students’ conceptions of citizenship failed to move beyond personal responsibility to include enhanced social consciousness and the importance of collective action. Thus, we raise critical questions about what constitutes “effective citizenship” in a democratic society and the role of higher education in preparing teachers to embody and enact such a vision.     

Invariants

This article is on the use of ‘invariants’ in mathematics illustrated with some simple examples.     

The Amish

The Old Order Amish are widely known because of their old-fashioned social and technological practices and characteristic dress (Figs. 1–4). They represent both a religious isolate and a genetic isolate. Their religion is of a fundamentalist variety known generically as anabaptist, that is, they oppose infant baptism. Economically they are capitalists living on individual family farms. A strong sense of mutual collaboration exists among the Amish, however, as illustrated by barn-raisings, and in many other ways.