Diagnosing students' difficulties in learning mathematics

This study considers the results of a diagnostic test of student difficulty and contrasts the difference in performance between the lower attaining quartile and the higher quartile. It illustrates a difference in qualitative thinking between those who succeed and those who fail in mathematics, illustrating a theory that those who fail are performing a more difficult type of mathematics (coordinating procedures) than those who succeed (manipulating concepts). Students who have to coordinate or reverse processes in time will encounter far greater difficulty than those who can manipulate symbols in a flexible way. The consequences of such a dichotomy and implications for remediation are then considered

Adsorption energy and spin state of first-row transition metals adsorbed on MgO(100)

Slab and cluster model spin-polarized calculations have been carried out to study various properties of isolated first-row transition metal atoms adsorbed on the anionic sites of the regular MgO(100) surface. The calculated adsorption energies follow the trend of the metal cohesive energies, indicating that the changes in the metal-support and metal-metal interactions along the series are dominated by atomic properties. In all cases, except for Ni at the generalized gradient approximation level, the number of unpaired electron is maintained as in the isolated metal atom. The energy required to change the atomic state from high to low spin has been computed using the PW91 and B3LYP density-functional-theory-based methods. PW91 fails to predict the proper ground state of V and Ni, but the results for the isolated and adsorbed atom are consistent within the method. B3LYP properly predicts the ground state of all first-row transition atom the high- to low-spin transition considered is comparable to experiment. In all cases, the interaction with the surface results in a reduced high- to low-spin transition energy

Cancer history and other personal factors affect quality of life in patients with hepatitis C

BACKGROUND: Although patients with chronic hepatitis C (CHC) have been found to have reduced quality of life, little is known about how other characteristics affect their quality of life. The purpose of this study was to investigate the effect of other characteristics, including history of cancer, on quality of life in patients with CHC. METHODS: One hundred forty patients from clinics at three hospitals in New York City completed a detailed epidemiologic interview about demographic and lifestyle characteristics and the SF-36 measuring health-related quality of life. We compared results from our patients to normative data using t-tests of differences between means. We used multivariate analyses to determine other personal and health-related factors associated with quality of life outcomes. RESULTS: Compared to normative data, these patients had reduced quality of life, particularly on physical functioning. The summary Physical Component Score (PCS) was 45.4 ± 10.6 and the Mental Component Score (MCS) was 48.2 ± 11.1, vs norms of 50 ± 10.0; p-values were <0.0001 and <0.05, respectively. In multivariate analyses, the PCS was significantly lower among those with cancer history, ≥ 2 other chronic conditions, less education, low physical activity, and higher alanine aminotransferase (ALT) levels. Cancer was more important for men, while other chronic conditions were more important for women. On the MCS, history of depression, low physical activity, alcohol use, and female gender were independently associated with poorer scores. CONCLUSION: Several health and lifestyle factors independently influence quality of life in CHC patients. Different factors are important for men and women

Egalitarian justice and expected value

According to all-luck egalitarianism, the differential distributive effects of both brute luck, which defines the outcome of risks which are not deliberately taken, and option luck, which defines the outcome of deliberate gambles, are unjust. Exactly how to correct the effects of option luck is, however, a complex issue. This article argues that (a) option luck should be neutralized not just by correcting luck among gamblers, but among the community as a whole, because it would be unfair for gamblers as a group to be disadvantaged relative to non-gamblers by bad option luck; (b) individuals should receive the warranted expected results of their gambles, except insofar as individuals blamelessly lacked the ability to ascertain which expectations were warranted; and (c) where societal resources are insufficient to deliver expected results to gamblers, gamblers should receive a lesser distributive share which is in proportion to the expected results. Where all-luck egalitarianism is understood in this way, it allows risk-takers to impose externalities on non-risk-takers, which seems counterintuitive. This may, however, be an advantage as it provides a luck egalitarian rationale for assisting ‘negligent victims’

Introduction to the special issue: after trust

“Trust” has long been seen as critical to the success and durability of trading networks, and conceptualised as a positive moral sentiment that is embedded in shared kinship, ethnicity or friendship, or in shared frameworks of morality. Other recent studies of business communities suggest that the ability to work in settings characterised by pervasive mistrust is a key factor in the development of commercial acumen and determining success. This Special Issue argues that the focus on trust and mistrust, and the underlying concern with ethics and morality, obscure equally critical aspects that inform the durability of trading networks. It offers ethnographic accounts of different inter-Asian trading networks active in the city of Yiwu. One of China’s most dynamic and diverse ‘international trade cities’, Yiwu is home to the largest wholesale market of small commodities in the world, and attracts traders and merchants from across the planet; over 12,000 foreign traders are also resident in the city. The collected articles analyse the durability of these networks in relation to broader geopolitical processes and contexts, arguing that success often depends on the ability to negotiate geopolitical shifts and the faultlines of political identity. The articles trace traders’ efforts to create institutions that allow them to withstand geopolitical transformations. They also document the ability of trading networks to operate flexibly across different social fields, showing that resilience often depends on the ability to navigate and profit from shifting relations between economic, political and familial domains

Towards a resolution of some outstanding issues in transitive research: an empirical test on middle childhood

Transitive Inference (deduce B > D from B > C and C > D) can help us to understand other areas of sociocognitive development. Across three experiments, learning, memory, and the validity of two transitive paradigms were investigated. In Experiment 1 (N = 121), 7-year-olds completed a three-term nontraining task or a five-term task requiring extensive-training. Performance was superior on the three-term task. Experiment 2 presented 5–10-year-olds with a new five-term task, increasing learning opportunities without lengthening training (N = 71). Inferences improved, suggesting children can learn five-term series rapidly. Regarding memory, the minor (CD) premise was the best predictor of BD-inferential performance in both task-types. However, tasks exhibited different profiles according to associations between the major (BC) premise and BD inference, correlations between the premises, and the role of age. Experiment 3 (N = 227) helped rule out the possible objection that the above findings simply stemmed from three-term tasks with real objects being easier to solve than computer-tasks. It also confirmed that, unlike for five-term task (Experiments 1 & 2), inferences on three-term tasks improve with age, whether the age range is wide (Experiment 3) or narrow (Experiment 2). I conclude that the tasks indexed different routes within a dual-process conception of transitive reasoning: The five-term tasks indexes Type 1 (associative) processing, and the three-term task indexes Type 2 (analytic) processing. As well as demonstrating that both tasks are perfectly valid, these findings open up opportunities to use transitive tasks for educability, to investigate the role of transitivity in other domains of reasoning, and potentially to benefit the lived experiences of persons with developmental issues

Crossing Eurasia: trans-regional Afghan trading networks in China and beyond

An expanding body of literature in the field of Central Asian studies has brought attention to the problems of considering the region's complex dynamics through the lens of its nation-states. Comparatively less attention has been paid to the role played by trans-regional circulations in connecting parts of Central Asia to the wider world. This paper situates ethnographic work on trans-regional networks of Afghan traders in China, Central Asia, Russia, Ukraine and the UK in relation to the literature on trans-regional connections and circulation societies. Ethnographically it demonstrates the multi-polar nature of these trans-regional networks, and the importance of trading nodes, especially the Chinese city of Yiwu, to their formation and ongoing vitality

Compromiso organizacional y satisfacción laboral: un estudio exploratorio en unidades de salud familiar portuguesas

Explorou-se a relação entre compromisso organizacional e satisfação laboral nos colaboradores de unidades de saúde familiar. Participaram seis unidades de saúde familiar do norte de Portugal e 105 profissionais (médico, enfermeiros e secretários clínicos). Utilizaram-se as adaptações portuguesas da Escala do Compromisso Organizacional de Meyer & Allen (1997) e do Questionário de Satisfação com o Trabalho (Spector, 1985). Os resultados sugerem associação positiva entre compromisso organizacional e satisfação laboral. Os profissionais estão moderadamente satisfeitos e comprometidos com as unidades de saúde familiar, sendo a natureza do trabalho, a relação com os colegas e a comunicação os aspectos mais satisfatórios, e as recompensas o mais insatisfatório. A componente afetiva do compromisso evidencia-se, salientando o envolvimento e a identificação dos profissionais com o projeto unidades de saúde familiar. O modelo de regressão linear revelou-se significativo, o compromisso organizacional explica 22,7% da variância da satisfação com o trabalho. Para esta amostra, o compromisso organizacional prediz a satisfação com o trabalho.This study explored the relationship between organizational commitment and job satisfaction among workers in family health units. Six family health units in the North of Portugal participated, including 105 health professionals (physicians, nurses, and clinical secretaries). The study used the Portuguese adaptations of the Organizational Commitment Scale by Meyer & Allen (1997) and the Job Satisfaction Survey (Spector, 1985). The results suggest a positive association between organizational commitment and job satisfaction. The professionals are moderately satisfied and committed to the family health units; the most satisfactory aspects are the nature of the work, relationship to coworkers, and communication, while pay is the most unsatisfactory. The affective component of the commitment appears, highlighting the professionals' involvement in (and identification with) the family health units project. The linear regression model proved significant, and organizational commitment explains 22.7% of the variance in job satisfaction. For this sample, organizational commitment predicts job satisfaction.Instituto Nacional de Saúde Dr Ricardo Jorgeinfo:eu-repo/semantics/publishedVersio

Developmental toxicity and brain aromatase induction by high genistein concentrations in zebrafish embryos

Genistein is a phytoestrogen found at a high level in soybeans. In vitro and in vivo studies showed that high concentrations of genistein caused toxic effects. This study was designed to test the feasibility of zebrafish embryos for evaluating developmental toxicity and estrogenic potential of high genistein concentrations. The zebrafish embryos at 24 h post-fertilization were exposed to genistein (1 × 10−4 M, 0.5 × 10−4 M, 0.25 × 10−4 M) or vehicle (ethanol, 0.1%) for 60 h. Genistein-treated embryos showed decreased heart rates, retarded hatching times, decreased body length, and increased mortality in a dose-dependent manner. After 0.25 × 10−4 M genistein treatment, malformations of survived embryos such as pericardial edema, yolk sac edema, and spinal kyphosis were also observed. TUNEL assay results showed apoptotic DNA fragments in brain. This study also confirmed the estrogenic potential of genistein by EGFP expression in the brain of the mosaic reporter zebrafish embryos. This study first demonstrated that high concentrations of genistein caused a teratogenic effect on zebrafish embryos and confirmed the estrogenic potential of genistein in mosaic reporter zebrafish embryos