910 research outputs found
FIR Filter Implementation by Efficient Sharing of Horizontal and Vertical Common Sub-expressions
No abstract availabl
Dynamical versus Bayesian Phase Transitions in a Toy Model of Superposition
We investigate phase transitions in a Toy Model of Superposition (TMS) using
Singular Learning Theory (SLT). We derive a closed formula for the theoretical
loss and, in the case of two hidden dimensions, discover that regular -gons
are critical points. We present supporting theory indicating that the local
learning coefficient (a geometric invariant) of these -gons determines phase
transitions in the Bayesian posterior as a function of training sample size. We
then show empirically that the same -gon critical points also determine the
behavior of SGD training. The picture that emerges adds evidence to the
conjecture that the SGD learning trajectory is subject to a sequential learning
mechanism. Specifically, we find that the learning process in TMS, be it
through SGD or Bayesian learning, can be characterized by a journey through
parameter space from regions of high loss and low complexity to regions of low
loss and high complexity
Distinct Roles of Tensile and Compressive Stresses in Graphitizing and Properties of Carbon Nanofibers
It is generally accepted that inducing molecular alignment in a polymer precursor via mechanical stresses influences its graphitization during pyrolysis. However, our understanding of how variations of the imposed mechanics can influence pyrolytic carbon microstructure and functionality is inadequate. Developing such insight is consequential for different aspects of carbon MEMS manufacturing and applicability, as pyrolytic carbons are the main building blocks of MEMS devices. Herein, we study the outcomes of contrasting routes of stress-induced graphitization by providing a comparative analysis of the effects of compressive stress versus standard tensile treatment of PAN-based carbon precursors. The results of different materials characterizations (including scanning electron microscopy, Raman and X-ray photoelectron spectroscopies, as well as high-resolution transmission electron microscopy) reveal that while subjecting precursor molecules to both types of mechanical stresses will induce graphitization in the resulting pyrolytic carbon, this effect is more pronounced in the case of compressive stress. We also evaluated the mechanical behavior of three carbon types, namely compression-induced (CIPC), tension-induced (TIPC), and untreated pyrolytic carbon (PC) by Dynamic Mechanical Analysis (DMA) of carbon samples in their as-synthesized mat format. Using DMA, the elastic modulus, ultimate tensile strength, and ductility of CIPC and TIPC films are determined and compared with untreated pyrolytic carbon. Both stress-induced carbons exhibit enhanced stiffness and strength properties over untreated carbons. The compression-induced films reveal remarkably larger mechanical enhancement with the elastic modulus 26 times higher and tensile strength 2.85 times higher for CIPC compared to untreated pyrolytic carbon. However, these improvements come at the expense of lowered ductility for compression-treated carbon, while tension-treated carbon does not show any loss of ductility. The results provided by this report point to the ways that the carbon MEMS industry can improve and revise the current standard strategies for manufacturing and implementing carbon-based micro-devices
Anemia, costs and mortality in Chronic Obstructive Pulmonary Disease
BACKGROUND: Little is known about cost implications of anemia and its association with mortality in chronic obstructive pulmonary disease (COPD). This claims analysis addresses these questions. METHODS: Using the the US Medicare claims database (1997–2001), this study identified Medicare enrollees with an ICD-9 diagnosis of COPD. Concomitant anemia was identified based on ICD-9 codes or receipt of transfusions. Persons with anemia secondary to another disease state, a nutritional deficiency or a hereditary disease were excluded. Medicare claims and payments, resource utilization and mortality were compared between COPD patients with and without anemia. RESULTS: Of the 132,424 enrollees with a COPD diagnosis, 21% (n = 27,932) had concomitant anemia. At baseline, anemic patients were older, had more co-morbidities and higher rates of health care resource use than non-anemic individuals with COPD. In a univariate analysis annual Medicare payments for persons with anemia were more than double for those without anemia (649, p < 0.001), the direction maintained in all categories of payments. Adjusting for demographics, co-morbidities, and other markers of disease severity revealed that anemia was independently associated with 3,299 to $3,865) in Medicare annual reimbursements. The mortality rate among COPD patients with anemia was 262 vs. 133 deaths per 1,000 person-years among those without anemia (p < 0.001). CONCLUSION: Anemia was present in 21% of COPD patients. Although more prevalent in more severely ill COPD patients, anemia significantly and independently contributes to the costs of care for COPD and is associated with increased mortality
Comparative Analysis of Ribosomal Protein Gene, eL14 Expression between Two Types of Colorectal Carcinoma Cell Lines
Association between the expression of ribosomal protein (RP) genes and cancer is widely known. More specifically, the extra-ribosomal functions of RPs have been linked to carcinogenesis. The ribosomal protein gene, eL14 has been reported to be associated with malignancy of the colorectum, albeit of mechanism yet unclear. Its expression in cells derived from different tissue origin of colorectal carcinoma (CRC) has never been explored. Therefore, this study aims to comparatively analyse the expression pattern of eL14 between two different CRC cell lines (DLD-1 and HCT116). It involved a conventional gene expression analysis, the Reverse-Transcriptase PCR (RT-PCR) assays. Products of RT-PCR assay were resolved via an agarose gel electrophoresis method, and band intensities of amplicons were documented and quantified using TotalLab Quant software. We observed differential expression patterns of eL14 between DLD-1 and HCT116 cells, but statistical analysis revealed insignificant differences. Therefore, the relevance of eL14 as a biomarker to distinguish between different colorectal cancer cells is suggestive but not conclusive
Fact Sheet: Conducting effective skill building workshops
Workshops that build both research and clinical skills are popular learning events in primary health care. They are cost effective compared with individual training activities and provide a means of connecting the material to be learned to the leaders' context, as well as providing opportunities for group interaction
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