213 research outputs found

    Early Forest Fire Detection via Principal Component Analysis of Spectral and Temporal Smoke Signature

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    The goal of this study is to develop a smoke detecting algorithm using digital image processing techniques on multi-spectral (visible & infrared) video. By utilizing principal component analysis (PCA) followed by spatial filtering of principal component images the location of smoke can be accurately identified over a period of exposure time with a given frame capture rate. This result can be further analyzed with consideration of wind factor and fire detection range to determine if a fire is present within a scene. Infrared spectral data is shown to contribute little information concerning the smoke signature. Moreover, finalized processing techniques are focused on the blue spectral band as it is furthest away from the infrared spectral bands and because it experimentally yields the largest footprint in the processed principal component images in comparison to other spectral bands. A frame rate of .5 images/sec (1 image every 2 seconds) is determined to be the maximum such that temporal variance of smoke can be captured. The study also shows eigenvectors corresponding to the principal components that best represent smoke and are valuable indications of smoke temporal signature. Raw video data is taken through rigorous pre-processing schemes to align frames from respective spectral band both spatially and temporally. A multi-paradigm numerical computing program, MATLAB, is used to match the field of view across five spectral bands: Red, Green, Blue, Long-Wave Infrared, and Mid-Wave Infrared. Extracted frames are aligned temporally from key frames throughout the data capture. This alignment allows for more accurate digital processing for smoke signature. v Clustering analysis on RGB and HSV value systems reveal that color alone is not helpful to segment smoke. The feature values of trees and other false positives are shown to be too closely related to features of smoke for in solely one instance in time. A temporal principal component transform on the blue spectral band eliminates static false positives and emphasizes the temporal variance of moving smoke in images with higher order. A threshold adjustment is applied to a blurred blue principal component of non-unity principal component order and smoke results can be finalized using median filtering. These same processing techniques are applied to difference images as a more simple and traditional technique for identifying temporal variance and results are compared

    Activation and repression of transcription by differential contact: two sides of a coin

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    Activation and repression of transcription are primarily caused by gene regulatory proteins (activators and repressors), which act by binding to specific sites on DNA. The steps from initial binding of RNA polymerase to the elongating complex are characterized by many intermediates, each with a discrete structure, offering many mechanistic possibilities for regulator actions. It has been shown in some systems that the activator acts by helping RNA polymerase or other associated factors to bind (recruitment) and/or by influencing a postrecruitment step (isomerization, promoter clearance, etc.) (1-7). We have used the term recruitment for referring to assistance only on the initial binding step of RNA polymerase. We caution that a postbinding step may be indistinguishable from the recruitment step if they are in rapid equilibrium. Clearly, all activators do not act at the level of RNA polymerase recruitment to the promoters. There are activators demonstrated to help postbinding steps that have no effect on initial binding (4-7). Promoter-specific repression can occur by sterically hindering the binding of RNA polymerase or of, in principle, another essential transcription factor to the promoter (8, 9). However, other studies in several promoters, as was anticipated (10), point toward repressor action also through contact with promoter-bound RNA polymerase at a postbinding step (11-17). More interestingly, some regulators act as activator in one context and as repressor in another (13, 15). Although the contact regions on the surface of some regulators and of RNA polymerase have been mapped (18, 19), how these contacts cause activation or inhibition of transcription initiation in biochemical terms is not known. In principle, the contact may affect the process of transcription initiation (i) by allosteric modification of RNA polymerase and/or (ii) by energetic stabilization of an intermediate(s). Regulator-induced conformation changes in RNA polymerase by protein-protein contact may contribute to the regulation process. However, a regulator-RNA polymerase contact may play a fundamentally different role in transcription initiation. In this article, we provide a conceptual framework for the process of activator and repressor action through differential stabilization of one or more of the intermediate states of RNA polymerase-promoter complex by its contact with the regulator. We portray regulators as catalysts. From a thermodynamic point, we view that activators, like catalysts, lower the activation energy of some step(s) in the reaction pathway of transcription initiation. As discussed below, a similar energetic argument explains the action of repressors. To make our point, we discuss simple examples of DNA-binding regulators modulating RNA polymerase during transcription initiation in selected prokaryotic systems

    Identifying Nontraditional Epidemic Disease Risk Factors Associated with Major Health Events from World Health Organization and World Bank Open Data

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    Health events emerge from host, community, environment, and pathogen factors-forecasting epidemics is a complex task. We describe an exploratory analysis to identify economic risk factors that could aid epidemic risk assessment. A line list was constructed using the World Health Organization Disease Outbreaks News (2016-2018) and economic indicators from the World Bank. Poisson regression employing forward imputations was used to establish relationships with the frequency with which countries reported public health events. Economic indicators demonstrated strong performance appropriate for further assessment in surveillance programming. In our analysis, three economic indicators were significantly associated to event reporting: how much the country\u27s urban population changed, its average forest area, and a novel economic indicator we developed that assessed how much the gross domestic product changed per capita. Other economic indicators performed less well: changes in total, female, urban, and rural population sizes; population density; net migration; change in per cent forest area; total forest area; and another novel indicator, change in percent of trade as a fraction of the total economy. We then undertook a further analysis of the start of the current COVID-19 pandemic that revealed similar associations, but confounding by global disease burden is likely. Continued development of forecasting approaches capturing information relevant to whole-of-society factors (e.g., economic factors as assessed in our study) could improve the risk management process through earlier hazard identification and inform strategic decision processes in multisectoral strategies to preventing, detecting, and responding to pandemic-threat events

    Identifying Nontraditional Epidemic Disease Risk Factors Associated with Major Health Events from World Health Organization and World Bank Open Data

    Get PDF
    Health events emerge from host, community, environment, and pathogen factors-forecasting epidemics is a complex task. We describe an exploratory analysis to identify economic risk factors that could aid epidemic risk assessment. A line list was constructed using the World Health Organization Disease Outbreaks News (2016-2018) and economic indicators from the World Bank. Poisson regression employing forward imputations was used to establish relationships with the frequency with which countries reported public health events. Economic indicators demonstrated strong performance appropriate for further assessment in surveillance programming. In our analysis, three economic indicators were significantly associated to event reporting: how much the country\u27s urban population changed, its average forest area, and a novel economic indicator we developed that assessed how much the gross domestic product changed per capita. Other economic indicators performed less well: changes in total, female, urban, and rural population sizes; population density; net migration; change in per cent forest area; total forest area; and another novel indicator, change in percent of trade as a fraction of the total economy. We then undertook a further analysis of the start of the current COVID-19 pandemic that revealed similar associations, but confounding by global disease burden is likely. Continued development of forecasting approaches capturing information relevant to whole-of-society factors (e.g., economic factors as assessed in our study) could improve the risk management process through earlier hazard identification and inform strategic decision processes in multisectoral strategies to preventing, detecting, and responding to pandemic-threat events

    Effect of Epoxy Impregnation on the Moe and Mor of Intact and Failed Yellow-Poplar (Liriodendron Tulipifera L.) Sapwood Beams

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    The effects of epoxy impregnation on the MOR and MOE of intact and failed yellow-poplar (Liriodendron tulipifera L.) clear sapwood beams were investigated. Both impregnated and unimpregnated specimens were partially failed in bending, impregnated to stabilize the cracks, and retested. The presence of induced cracks had a significant effect on the MOR of the material after impregnation or reimpregnation, but not on the MOE. Both the MOR and MOE of the failed, then impregnated material exceeded the values for unimpregnated yellow-poplar

    Kinetics of transcription initiation at lacP1: multiple roles of cyclic amp receptor protein

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    The cyclic AMP receptor protein (CRP) acts as a transcription activator at many promoters of Escherichia coli. We have examined the kinetics of open complex formation at the lacP1 promoter using tryptophan fluorescence of RNA polymerase and DNA fragments with 2-aminopurine substituted at specific positions. Apart from the closed complex formation and promoter clearance, we were able to detect three steps. The first step after the closed complex formation leads to a rapid increase of 2-aminopurine fluorescence. This was followed by another rapid step in which quenching of tryptophan fluorescence of RNA polymerase was observed. The slowest step detected by 2-aminopurine fluorescence increase is assigned to the final open complex formation. We have found that CRP not only enhances RNA polymerase binding at the promoter, but also enhances the slowest isomerization step by about 2-fold. Furthermore, potassium permanganate probing shows that the conformation of the open complex in the presence of CRP appears qualitatively and quantitatively different from that in the absence of CRP, suggesting that contact with RNA polymerase is maintained throughout the transcription initiation
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