Modeling the developmental trajectories of rational number concept(s)

The present study focuses on the development of two sub-concepts necessary for a complete mathematical understanding of rational numbers, a) representations of the magnitudes of rational numbers and b) the density of rational numbers. While difficulties with rational number concepts have been seen in students' of all ages, including educated adults, little is known about the developmental trajectories of the separate sub-concepts. We measured 10- to 12-year-old students' conceptual knowledge of rational numbers at three time points over a one-year period and estimated models of their conceptual knowledge using latent variable mixture models. Knowledge of magnitude representations is necessary, but not sufficient, for knowledge of density concepts. A Latent Transition Analysis indicated that few students displayed sustained understanding of rational numbers, particularly concepts of density. Results confirm difficulties with rational number conceptual change and suggest that latent variable mixture models can be useful in documenting these processes.     

Are we using Thyroid Function Tests Appropriately?

Thyroid function tests are very important for the diagnosis and monitoring of patients with thyroid dysfunction. The guidelines recommend serum thyroid stimulating hormone (TSH) as the single most reliable test to diagnose all common forms of hypothyroidism and hyperthyroidism. The aim of this study was to analyze the ordering pattern for thyroid function tests by physicians and the analysis of results based on the clinical history. The mean age of the patients was 32.5 ± 6.5 years. Majority of samples (87.7% of total) were received from the departments of Medicine and Gynae. Thyroid profiles (47.5%) were ordered more frequently as compared to TSH only (46%). There was no significant difference in the percentage of normal reports for both types of tests. 77.8% of TFT and 76.6% of TSH samples had results within the reference range. The percentage of abnormal results was 13.7% in the patients who were screened for thyroid disorders. There is a need to redefine the case definition for thyroid dysfunction and order the appropriate test in a rational and cost effective manner.     

Deregulation of microRNA expression in thyroid tumors简

MicroRNAs (miRNAs or miRs) are endogenous non-coding RNAs that negatively regulate gene expression by binding to the 3′ non-coding regions of target mRNAs, resulting in their cleavage or blocking their translation. miRNAs may have an impact on cell differentiation, proliferation, and survival, and their deregulation can be inclined to diseases and cancers, including thyroid tumors. The purpose of this review is to summarize the existing findings of deregulated miRNAs in different types of thyroid tumors and to exhibit their potential target genes, especially to demonstrate those involved in tumor invasion and metastasis. In addition, new findings of circulating miRNA expression profiles, single nucleotide polymorphism (SNP) in thyroid tumors, and the correlation of somatic mutations with deregulated miRNA expression in thyroid tumors were all included in this review.     

Metastasis of gastric carcinoma to the thyroid and lung: a case report and review of literature

Cancer metastasis to the thyroid is extremely rare. The more commonly reported primary sites for metastasis to the thyroid are the kidney, breast, lung, colon, esophagus, and uterus. Thyroid metastasis from the stomach has only been reported in three cases. Herein, we report a 71-year-old man presenting with bilateral thyroid multinodular lesions. Bilateral near-total thyroidectomy was performed due to airway compression with related symptoms. Wedge resection of a suspicious pulmonary nodule, detected on CT, was performed for diagnosis. Polypoid lesions in the stomach were examined by trans-scopic biopsy. Poorly differentiated adenocarcinomas with the same histological profiles were noted at these three sites. The immunohistochemical staining for thyroglobulin of these specimens was negative. We conclude that a new thyroid mass appearing in a patient with present or prior malignancies should raise the concern of metastatic disease.     

面向学习者特征——行为数据融合的协同学习系统框架设计

文章将个性化学习和协同学习的教育理念结合起来,提出了一个基于数据融合技术的协同学习系统框架,以解决协同学习中个体学习目标往往得不到实现的问题。     

Profiling the Beliefs of the Forgotten Teachers: An Analysis of Intern Teachers’ Frameworks for Urban Science Teaching

The need to equip science teachers with knowledge, skills, and habits of mind to face the challenges of teaching science through inquiry informed this study, which analyzed the secondary science intern teachers’ beliefs about inquiry before, during, and following a series of 2 consecutive science methods courses in an attempt to document the effect of such experiences on their ability and willingness to infuse science inquiry in their science curricula. Nine science credentialing interns participated in the study. Data was gathered from their written reflections and various assignments throughout the methods courses. Results suggested that their beliefs changed significantly after the science methods courses. The implications of the study to secondary science teacher educators and researchers were highlighted.     

An audit of total and free thyroxine measurements in screening for hypo and hyperthyroidism in patients using chemiluminescence immunoassay

An audit of 2509 patient specimens analyzed for both total thyroxine (TT4) and free thyroxine (FT4) by the ACS-180 automated chemiluminescence immunoassay analyzer revealed that there were 219 discrepancies (8.7% of the total). A discrepancy was defined as one analyte within its reference range and the other outside. The discrepant results were divided into 4 groups: group A: normal TT4, but decreased FT4, 101 patients (4.0%); group B: increased TT4, normal FT4, 78 patients (3.1%); group C: decreased TT4, normal FT4, 34 patients (1.4%); and group D: normal TT4, increased FT4, 6 patients (0.2%). TSH measurements were available, by a 3^rd generation chemiluminescent assay, in 142 of these patients, and were consistent with the FT4 result in 72 patients, with TT4 in 61 cases and with neither in 9 patients. The clinical diagnosis was investigated in a subgroup of 43 endocrine patients. Thirteen of the 20 endocrine patients in group A were diagnosed as hypothyroid, with a measured serum TSH, in 11 of them, of median 14.6, range 1.2 to 46.2 μlU/ml. Eleven of the 19 endocrine patients in group B were on thyroid replacement, with a measured serum TSH, in 7 of them of <0.01 μlU/ml. The audit of current laboratory practice led to a suggestion to replace the current thyroid function screening strategy of measuring both TT4 and FT4 by the combination of FT4 and TSH. The reasons for the discrepancies and the alternative strategies for screening of thyroid function are discussed.     

Profiling Younger Adults’ Communication About Aging

According to the Communicative Ecology Model of Successful Aging (CEMSA), how people talk about age can have implications for how they cope with aging later in life. However, most research on communication and successful aging has focused on older adults. In this study, we use latent class analysis to profile how younger adults (age 18–39) communicate about aging and examine how these profiles relate to their attitudes toward aging (affect, efficacy, anxiety, and perceptions of successful aging). Consistent with past research on older adults, we found three distinct profiles of communication behavior (disengaged, engaged, and bantering). An engaged profile was clearly associated with the most positive attitudes toward aging, while a disengaged profile was associated with the least positive attitudes. These findings suggest that patterns of talk about aging may start early in life, underscoring the importance of studying communication about aging across the lifespan.     

早孕妇女甲状腺激素的测定结果分析

探讨人绒毛膜促性腺激素(hCG)是否具有垂体促甲状腺激素(TSH)样作用。方法:应用放射免疫方法(RIA)对65例旱孕妇女hCG与甲状腺激素水平进行测定。结果:早孕妇女Ⅰ组(停经35—50天)3,3’,5’-三碘甲状腺原氨酸(rT_3)水平升高,与正常对照组差异显著(P<0.01);早孕妇女Ⅱ组(停经51—80天)甲状腺素(T_4)、游离甲状腺素(FT_4)、rT_3水平均升高,与正常对照组差异显著(P<0.01);而两组早孕妇女的三碘甲状腺原氨酸(T_3)、游离三碘甲状腺原氨酸(FT_3)水平与正常对照组无明显差异(P>0.05)。结论:hCG具有TSH样作用,早孕妇女甲状腺激素水平升高为hCG促使甲状腺功能增强所致。