866 research outputs found

    TPACK in practice: a qualitative study of middle school Social Studies teachers in a 1:1 laptop environment

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    The purpose of this qualitative study was to examine what effective teaching with technology looked like in practice within middle grade Social Studies’ classrooms. An additional purpose was to understand how teachers’ combine content knowledge, pedagogical knowledge, and technological knowledge when making decisions about their curriculum. Guiding this study was a conceptual framework that suggests effective teaching with technology comes from technological pedagogical content knowledge (TPACK), a knowledge that is created by combining content knowledge, pedagogical knowledge, and technological knowledge (Mishra & Koehler, 2006). Lakeside Middle School was selected for this study due to both its commitment to technology integration and its implementation of a school wide 1:1 laptop initiative. Three middle grade Social Studies’ teachers at Lakeside were selected, one each from 6th, 7th, and 8th grade classrooms. A multiple case study methodology was used in this study. An observation protocol, designed specifically to capture TPACK moments during observations, was developed. Multiple data sources (interviews, observations, focus group, and artifacts) were collected and analyzed for emerging themes about the TPACK practices of each teacher. Using the data collected, a descriptive case study was written for each teacher. These descriptive case studies identified examples, grouped thematically, of TPACK in practice. These descriptive case studies also recorded each teacher’s beliefs about teaching, technology in education, and their own placement within the TPACK framework. Data analysis suggested that that TPACK is developed uniquely in each teacher, shaped by their beliefs and strengths in teaching. Analysis of the data also suggested that the TPACK framework may need to be rethought, in order to fully capture TPACK in practice. Included in this are discussions about how the TPACK framework model fails to account for any of the three teachers’ TPACK practices, discussions about the model’s failure to differentiate between depth and breadth of TPACK knowledge, and discussions about other factors that influence TPACK in practice, including students and teaching environment. The study findings have implications for teacher educators, teachers, and policy makers. Specifically, teacher education courses need to be developed to address the lack of TPACK knowledge that preservice teachers have. Additionally, new professional development sessions are needed for practicing teachers that focus on developing both the depth and breadth of their TPACK practices

    Affect presentation in infancy and toddlerhood as a predictor of later internalizing behaviors in early childhood

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    Affect representations during infancy have been associated with internalizing behaviors among children. However, few studies have examined the role of parenting practices in early childhood as shaping such associations. The current study used a large, population-stratified, randomly-selected sample of children living in rural areas under conditions of poverty to examine how positive and negative affect at 15 months was associated with internalizing behaviors at 58 months of age. Patterns of interaction between infant affects and positive and negative parenting behaviors at 24 were also examined and probed to determine whether these effects supported a diathesis stress model of early developmental processes related to later internalizing behaviors. Infant affect and parenting behaviors were measured using observational assessments and primary caregivers reported on children’s internalizing behaviors. Results indicated that positive parenting predicted lower levels of internalizing behaviors for all children. For European American children, lower levels of negative affect were associated with greater internalizing behaviors in the presence of low positive parenting. For African American children, more negative parenting was associated with higher levels of internalizing behaviors. These findings raise important questions regarding different levels of vulnerability to environmental influences among European American and African American young children and have the potential to inform interventions aimed at preventing and/or reducing internalizing behaviors

    Pericyte FAK negatively regulates Gas6/Axl signalling to suppress tumour angiogenesis and tumour growth

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    The overexpression of the protein tyrosine kinase, Focal adhesion kinase (FAK), in endothelial cells has implicated its requirement in angiogenesis and tumour growth, but how pericyte FAK regulates tumour angiogenesis is unknown. We show that pericyte FAK regulates tumour growth and angiogenesis in multiple mouse models of melanoma, lung carcinoma and pancreatic B-cell insulinoma and provide evidence that loss of pericyte FAK enhances Gas6-stimulated phosphorylation of the receptor tyrosine kinase, Axl with an upregulation of Cyr61, driving enhanced tumour growth. We further show that pericyte derived Cyr61 instructs tumour cells to elevate expression of the proangiogenic/protumourigenic transmembrane receptor Tissue Factor. Finally, in human melanoma we show that when 50% or more tumour blood vessels are pericyte-FAK negative, melanoma patients are stratified into those with increased tumour size, enhanced blood vessel density and metastasis. Overall our data uncover a previously unknown mechanism of tumour growth by pericytes that is controlled by pericyte FAK

    Architecture for a Social Assistive Robot in Cardiac Rehabilitation

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    Social robots are demonstrating to have potential in several healthcare applications, especially in rehabilitation areas. This paper presents an architecture for a socially assistive robot system for cardiac rehabilitation, based on a model-controller structure through a finite-state machine and a behaviour module. The platform has been designed to provide social support and assistance during the therapy, aiming to improve the quality of the provided service, as well as the engagement and performance of the patients. This architecture has been tested under clinical conditions with a patient during a typical therapy session. The results show that the proposed architecture is able to adapt to the various situations present during a session, providing a robust framework to further develop the robot's behaviour towards a more natural and intuitive interaction with the patients

    HAGE (DDX43) is a biomarker for poor prognosis and a predictor of chemotherapy response in breast cancer

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    Background: HAGE protein is a known immunogenic cancer-specific antigen. Methods: The biological, prognostic and predictive values of HAGE expression was studied using immunohistochemistry in three cohorts of patients with BC (n=2147): early primary (EP-BC; n=1676); primary oestrogen receptor-negative (PER-BC; n=275) treated with adjuvant anthracycline-combination therapies (Adjuvant-ACT); and primary locally advanced disease (PLA-BC) who received neo-adjuvant anthracycline-combination therapies (Neo-adjuvant-ACT; n=196). The relationship between HAGE expression and the tumour-infiltrating lymphocytes (TILs) in matched prechemotherapy and postchemotherapy samples were investigated. Results: Eight percent of patients with EP-BC exhibited high HAGE expression (HAGEþ) and was associated with aggressive clinico-pathological features (Ps<0.01). Furthermore, HAGEþexpression was associated with poor prognosis in both univariate and multivariate analysis (Ps<0.001). Patients with HAGE+ did not benefit from hormonal therapy in high-risk ER-positive disease. HAGE+ and TILs were found to be independent predictors for pathological complete response to neoadjuvant-ACT; P<0.001. A statistically significant loss of HAGE expression following neoadjuvant-ACT was found (P=0.000001), and progression-free survival was worse in those patients who had HAGE+ residual disease (P=0.0003). Conclusions: This is the first report to show HAGE to be a potential prognostic marker and a predictor of response to ACT in patients with BC

    Secular evolution versus hierarchical merging: galaxy evolution along the Hubble sequence, in the field and rich environments

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    In the current galaxy formation scenarios, two physical phenomena are invoked to build disk galaxies: hierarchical mergers and more quiescent external gas accretion, coming from intergalactic filaments. Although both are thought to play a role, their relative importance is not known precisely. Here we consider the constraints on these scenarios brought by the observation-deduced star formation history on the one hand, and observed dynamics of galaxies on the other hand: the high frequency of bars and spirals, the high frequency of perturbations such as lopsidedness, warps, or polar rings. All these observations are not easily reproduced in simulations without important gas accretion. N-body simulations taking into account the mass exchange between stars and gas through star formation and feedback, can reproduce the data, only if galaxies double their mass in about 10 Gyr through gas accretion. Warped and polar ring systems are good tracers of this accretion, which occurs from cold gas which has not been virialised in the system's potential. The relative importance of these phenomena are compared between the field and rich clusters. The respective role of mergers and gas accretion vary considerably with environment.Comment: 18 pages, 8 figures, review paper to "Penetrating Bars through Masks of Cosmic Dust: the Hubble Tuning Fork Strikes a New Note", Pilanesberg, ed. D. Block et al., Kluwe

    Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer

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    Introduction: In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the nonspecific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets. Methods: We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription. Results and conclusion: Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies

    Cingulate cortex hypoperfusion predicts Alzheimer's disease in mild cognitive impairment

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    BACKGROUND: Mild cognitive impairment (MCI) was recently described as a heterogeneous group with a variety of clinical outcomes and high risk to develop Alzheimer's disease (AD). Regional cerebral blood flow (rCBF) as measured by single photon emission computed tomography (SPECT) was used to study the heterogeneity of MCI and to look for predictors of future development of AD. METHODS: rCBF was investigated in 54 MCI subjects using Tc-99m hexamethylpropyleneamine oxime (HMPAO). An automated analysis software (BRASS) was applied to analyze the relative blood flow (cerebellar ratios) of 24 cortical regions. After the baseline examination, the subjects were followed clinically for an average of two years. 17 subjects progressed to Alzheimer's disease (PMCI) and 37 subjects remained stable (SMCI). The baseline SPECT ratio values were compared between PMCI and SMCI. Receiver operating characteristic (ROC) analysis was applied for the discrimination of the two subgroups at baseline. RESULTS: The conversion rate of MCI to AD was 13.7% per year. PMCI had a significantly decreased rCBF in the left posterior cingulate cortex, as compared to SMCI. Left posterior cingulate rCBF ratios were entered into a logistic regression model for ROC curve calculation. The area under the ROC curve was 74%–76%, which indicates an acceptable discrimination between PMCI and SMCI at baseline. CONCLUSION: A reduced relative blood flow of the posterior cingulate gyrus could be found at least two years before the patients met the clinical diagnostic criteria of AD

    Sphingomyelin Functions as a Novel Receptor for Helicobacter pylori VacA

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    The vacuolating cytotoxin (VacA) of the gastric pathogen Helicobacter pylori binds and enters epithelial cells, ultimately resulting in cellular vacuolation. Several host factors have been reported to be important for VacA function, but none of these have been demonstrated to be essential for toxin binding to the plasma membrane. Thus, the identity of cell surface receptors critical for both toxin binding and function has remained elusive. Here, we identify VacA as the first bacterial virulence factor that exploits the important plasma membrane sphingolipid, sphingomyelin (SM), as a cellular receptor. Depletion of plasma membrane SM with sphingomyelinase inhibited VacA-mediated vacuolation and significantly reduced the sensitivity of HeLa cells, as well as several other cell lines, to VacA. Further analysis revealed that SM is critical for VacA interactions with the plasma membrane. Restoring plasma membrane SM in cells previously depleted of SM was sufficient to rescue both toxin vacuolation activity and plasma membrane binding. VacA association with detergent-resistant membranes was inhibited in cells pretreated with SMase C, indicating the importance of SM for VacA association with lipid raft microdomains. Finally, VacA bound to SM in an in vitro ELISA assay in a manner competitively inhibited by lysenin, a known SM-binding protein. Our results suggest a model where VacA may exploit the capacity of SM to preferentially partition into lipid rafts in order to access the raft-associated cellular machinery previously shown to be required for toxin entry into host cells
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