Determinants of bone mineral density in patients on haemodialysis or peritoneal dialysis – a cross-sectional,longitudinal study

Introduction:

The aim of the study was to identify biomarkers of alteration in bone mineral density (BMD) in patients on haemodialysis (HD) and peritoneal dialysis (PD).

Materials and methods:

In a cross-sectional, longitudinal study dual-energy X-ray absorptiometry scans were performed in 146 HD-patients and 28 PD-patients. Follow-up after 14 months (mean) was conducted in 73 patients. As potential biomarkers we investigated parathyroid hormone (PTH), 25-hydroxy vitamin-D, ionised calcium, albumin, phosphate, and total alkaline phosphatases (t-ALP).

Results:

Both groups of dialysis patients had lower BMD in the femoral neck (BMD_neck) (P < 0.001) and forearm (BMD_forearm) (P < 0.001) compared to healthy controls, but comparable BMD in the lumbar spine (BMD_spine). BMD did not differ between dialysis types, but patients ever-treated with glucocorticoids had significantly lower BMD, while patients with polycystic kidney disease had higher BMD. BMD correlated with body weight, actual age, age at initiation of dialysis, duration of dialysis and levels of PTH and t-ALP. However, t-ALP only remained associated with low BMD_spine after adjusting for other factors (P = 0.001). In the follow-up study all patients had decreased BMD in all three locations, but only for the lumbar spine there was a significant association between BMD and the bone markers t-ALP (P = 0.009) and PTH (P = 0.013).

Conclusions:

Both HD and PD patients have low BMD, and increased concentrations of t-ALP is associated BMD_spine after adjustment, while PTH and t-ALP is associated with decrease in BMD_spine over time. This substantiates the use of these biomarkers in both types of dialysis patients.     

A comparison of blood pressure in term, low birth-weight infants of smoking and nonsmoking mothers

Infants exposed to the components of cigarette smoke in utero are at an increased risk for perinatal death, low birth weight, sudden infant death syndrome, and premature delivery. The purpose of this pilot study was to compare blood pressure values in term low-birth weight infants (相似文献   

Development of a Physical Education Teaching Efficacy Scale

Relationships have been found between teacher efficacy and many teaching and learning variables, but few researchers have examined teaching efficacy in physical education. The instrument reported here, the Physical Education Teaching Efficacy Scale, was developed based on the teaching efficacy literature, existing scales, and National Association for Sport and Physical Education's Teacher Education Standards. Students attending 11 institutions who are majoring in regular and alternate physical education teacher education and who are at different stages of preparation (N?=?592) completed the initial survey. Exploratory, followed by confirmatory, factor analysis resulted in a 35-item, 7-factor scale. Factors were Content Knowledge, which were activities one might teach; Applying Scientific Knowledge in Teaching, which reflected academic content; Accommodating Skill Differences; Teaching Students with Special Needs; Instruction, which included management, motivation, and instruction; Using Technology; and Assessment. Results support that the Physical Education Teaching Efficacy Scale addresses many aspects of teaching physical education and meets research criteria for validity and reliability.     

The neuroscience of perceptual categorization in pigeons: A mechanistic hypothesis

We are surrounded by an endless variation of objects. The ability to categorize these objects represents a core cognitive competence of humans and possibly all vertebrates. Research on category learning in nonhuman animals started with the seminal studies of Richard Herrnstein on the category “human” in pigeons. Since then, we have learned that pigeons are able to categorize a large number of stimulus sets, ranging from Cubist paintings to English orthography. Strangely, this prolific field has largely neglected to also study the avian neurobiology of categorization. Here, we present a hypothesis that combines experimental results and theories from categorization research in pigeons with neurobiological insights on visual processing and dopamine-mediated learning in primates. We conclude that in both fields, similar conclusions on the mechanisms of perceptual categorization have been drawn, despite very little cross-reference or communication between these two areas to date. We hypothesize that perceptual categorization is a two-component process in which stimulus features are first rapidly extracted in a feed-forward process, thereby enabling a fast subdivision along multiple category borders. In primates this seems to happen in the inferotemporal cortex, while pigeons may primarily use a cluster of associative visual forebrain areas. The second process rests on dopaminergic error-prediction learning that enables prefrontal areas to connect top down the relevant visual category dimension to the appropriate action dimension.     

Student Summative Evaluation of Teaching: code of practice

The following code of practice has been developed by the Association of University Staff (AUS) of New Zealand (Inc.) with Dr Cedric Hall, Director, University Teaching Development Centre (UTDC), Victoria University of Wellington. The code deals with the use of student evaluations of teaching for summative decision making (e.g. promotion, tenure, etc.). A draft of the AUS code was distributed to the centres responsible for academic staff development in each university and all committees of AUS for comment. We thank the individuals and groups concerned for their comments and advice. Appropriate changes have been made to the code to take account of the suggestions provided. The AUS code on student summative evaluation of teaching is for the use of AUSNZ members and New Zealand universities. The code is intended to encourage good professional practice in the use of student summative evaluation of teaching and teaching staff. AUS recognises that the contents of the code will need to be reviewed from time to time to take account of changing practices and educational developments within institutions. AUS recognises that student views can be a relevant consideration in overall evaluation of teaching quality, and that they can properly have a place in decision making in relation to tenure and promotion for teaching staff. However, varying practices in ascertaining student views have led (both in New Zealand and internationally) to instances of such decisions being based on invalid and unreliable data from student views. Bad practice in these areas reflects poorly on the institution(s), as well as being unfair to staff; in some instances, it may also be in breach of current legislation. This Code of Practice is based on the belief that any evaluation should provide valid (i.e. relevant and useful) and reliable (i.e. accurate) information on the quality of a person's teaching. AUS believes that teaching quality must be judged in context: the type and purpose of the teaching, the background of the students, the resources available and the voluntary/compulsory nature of the course, should all be considered. Validity and reliability, therefore, relate not only to the measurements that are made of a person's teaching performance, but also to the interpretation of the results.     

Introduction to the Special Issue: Learning from Moshe, Hu Hu Zhu and Khokha: Insights into the Global Application of the Formative Research Component of the Sesame Workshop Model

For over three decades, Sesame Workshop has produced high quality educational media for young children throughout the world. The success of these productions can be attributed in large measure to the application of a systematic production model that brings together professionals from a range of backgrounds. Using examples from the six studies presented in this special issue, this paper illustrates ways in which one element of the production process - formative research - has been used to create effective educational media in the United States, South Africa, Egypt and China. Beyond the value to the production process, lessons learned from formative studies provide insights into the development of new research methodologies. In addition, such studies, when looked at in a global context, offer perspective on the knowledge and learning of children of different cultures.     

Context specificity of conditioning in flavor-aversion learning: Extinction and blocking tests

In three experiments using rats as subjects, we investigated the degree to which a conditioned flavor aversion transfers from one context to another. Experiment 1, using a one-trial conditioning procedure, found no effect of a change of context on a conditioned aversion. Experiment 2 employed a multitrial procedure and demonstrated that a conditioned aversion was extinguished more rapidly after a change of context. Experiment 3 showed that context change decreased the effectiveness with which a conditioned flavor could block acquisition of an aversion by a second flavor. It is argued that these data cannot be explained in associative terms, and that they constitute evidence of conditionality in a simple aversive conditioning procedure.     

Psychosocial Adjustment among Children Experiencing Persistent and Intermittent Family Economic Hardship

Much research on family economic hardship and its effects on children has been cross-sectional in nature, has focused primarily on white children, and has assessed the impact of episodic rather than chronic economic difficulties. In contrast, the present research was designed to study outcomes associated with persistent economic hardship among a heterogeneous group of children over time. Results showed that, for both black and white children, a broad range of difficulties was associated with enduring economic hardship. Children who experienced persistent family economic hardship were more likely than those who did not to have difficulties in peer relations, show conduct problems at school, and report low self-esteem. Children who experienced intermittent family economic hardship fell between the other 2 groups. Connections between persistent economic hardship and psychosocial adjustment were more pronounced for boys than for girls. Consistent with suggestions by a number of investigators, the impact of economic hardship on children in the present sample was mediated in part by its association with parental behavior.