12,167 research outputs found
On the complemented subspaces of the Schreier spaces
It is shown that the Schreier space X admits a set of continuum cardinality
whose elements are mutually incomparable complemented subspaces spanned by
subsequences of the natural Schauder basis of X.Comment: 26 pages, AMS-LaTe
In vivo analysis of NHPX reveals a novel nucleolar localization pathway involving a transient accumulation in splicing speckles
The NHPX protein is a nucleolar factor that binds directly to a conserved RNA target sequence found in nucleolar box C/D snoRNAs and in U4 snRNA. Using enhanced yellow fluorescent protein (EYFP)– and enhanced cyan fluorescent protein–NHPX fusions, we show here that NHPX is specifically accumulated in both nucleoli and Cajal bodies (CBs) in vivo. The fusion proteins display identical localization patterns and RNA binding specificities to the endogenous NHPX. Analysis of a HeLa cell line stably expressing EYFP–NHPX showed that the nucleolar accumulation of NHPX was preceded by its transient accumulation in splicing speckles. Only newly expressed NHPX accumulated in speckles, and the nucleolar pool of NHPX did not interchange with the pool in speckles, consistent with a unidirectional pathway. The transient accumulation of NHPX in speckles prior to nucleoli was observed in multiple cell lines, including primary cells that lack CBs. Inhibitor studies indicated that progression of newly expressed NHPX from speckles to nucleoli was dependent on RNA polymerase II transcription, but not on RNA polymerase I activity. The data show a specific temporal pathway involving the sequential and directed accumulation of NHPX in distinct subnuclear compartments, and define a novel mechanism for nucleolar localization
The Application of a Cylindrical-spherical Floating Ring Bearing as a Device to Control Stability of Turbogenerators
The development of a new device to control stability of turbogenerators is described. The device comprises a floating ring installed between the journal and bearing housing of a fluid film bearing. The journal and the inner surface of the ring are cylindrical while the outer surface of the ring and bearing surface are spherical providing axial location of the ring and self-alignment of the bearing. The employment of this device would lead to a consistent machine performance. System stability may be controlled by changing a number of bearing and floating ring parameters. This device also offers an additional advantage of having a very low frictional characteristic. A feasibility study was carried out to investigate the suitability of the new device to turbogenerator applications. Both theoretical analysis and experimental observations were carried out. Initial results suggest that the new floating ring device is a competitive alternative to other conventional arrangements
A psychometric evaluation of a negative mood scale in the MDS-HC using a large sample of community-dwelling Hong Kong Chinese older adults
Background: negative mood is an important construct when assessing the health of older persons. The profile of mood states questionnaire is commonly used to measure mood; however, it might not be suitable for older adults with low education level and those who are not originated North American.Objective: to examine a negative mood scale formed by nine items in the Mood Section of the Minimum Data Set-Home Care of the Resident Assessment Instrument. Methods: a secondary analysis of data from 3,523 older persons aged 60 or over who had first applied for the long-term care services in Hong Kong and completed the screening tool in 2006. Exploratory and confirmatory factor analyses were used to test the factor structure and multiple-group confirmatory factor analysis to test the gender invariance of the Negative Mood Scale in the Minimum Data Set-Home Care. Its reliability using Cronbach's alpha was examined. Results: both a three-factor model at the first level and a one-factor model at the second level provided excellent fits to the overall data, and held equally well for both males and females, and two randomly split samples. Multiple-group confirmatory factor analyses revealed both genders demonstrating an equivalent pattern of factor loadings. Cronbach's alpha value was acceptable for the overall data (0.66). Conclusions: the Negative Mood Scale is a reliable and valid scale and both genders responded to it using the same framework and metric, suggesting it could be used to measure negative mood in Chinese community-dwelling older adults. Further testing of the instrument is needed. © The Author 2011. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved.postprin
An evaluation of the factor structure of the instrumental activities of daily living involvement and capacity scales of the minimum data set for home care for elderly Chinese community dwellers in Hong Kong
The objective of this study was to evaluate the factor structure of the Instrumental Activities of Daily Living (IADL) Involvement and Capacity scales of the Chinese version of the Minimum Data Set-Home Care (MDS-HC) in a sample of Chinese older adults living in Hong Kong (n=3,523). The results of confirmatory factor analyses supported the one-factor model for both IADL Involvement and IADL Capacity scales. Evidence indicated that both scales had good internal consistency (.88) and were reliable and valid in assessing IADL among elderly Chinese community dwellers.postprin
A Population-Based Ultra-Widefield Digital Image Grading Study for Age-Related Macular Degeneration-Like Lesions at the Peripheral Retina.
Our understanding of the relevance of peripheral retinal abnormalities to disease in general and in age-related macular degeneration (AMD) in particular is limited by the lack of detailed peripheral imaging studies. The purpose of this study was to develop image grading protocols suited to ultra-widefield imaging (UWFI) in an aged population
Silicon solar cell process development, fabrication, and analysis
Two large cast ingots were evaluated. Solar cell performance versus substrate position within the ingots was obtained and the results are presented. Dendritic web samples were analyzed in terms of structural defects, and efforts were made to correlate the data with the performance of solar cells made from the webs
Silicon solar cell process development, fabrication and analysis
Solar cells were fabricated from EFG ribbons dendritic webs, cast ingots by heat exchanger method, and cast ingots by ubiquitous crystallization process. Baseline and other process variations were applied to fabricate solar cells. EFG ribbons grown in a carbon-containing gas atmosphere showed significant improvement in silicon quality. Baseline solar cells from dendritic webs of various runs indicated that the quality of the webs under investigation was not as good as the conventional CZ silicon, showing an average minority carrier diffusion length of about 60 um versus 120 um of CZ wafers. Detail evaluation of large cast ingots by HEM showed ingot reproducibility problems from run to run and uniformity problems of sheet quality within an ingot. Initial evaluation of the wafers prepared from the cast polycrystalline ingots by UCP suggested that the quality of the wafers from this process is considerably lower than the conventional CZ wafers. Overall performance was relatively uniform, except for a few cells which showed shunting problems caused by inclusions
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