5,841 research outputs found

    Online support vector machine application for model based fault detection and isolation of HVAC system

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    Abstract—Preventive maintenance plays an important role in Heating, Ventilation and Air Conditioning (HVAC) system. One cost effective strategy is the development of analytic fault detection and isolation (FDI) module by online monitoring the key variables of HAVC systems. This paper investigates realtime FDI for HAVC system by using online Support Vector Machine (SVM), by which we are able to train a FDI system with manageable complexity under real time working conditions. It is also proposed a new approach which allows us to detect unknown faults and updating the classifier by using these previously unknown faults. Based on the proposed approach, a semi unsupervised fault detection methodology has been developed for HVAC system

    Prevalence of Newcastle disease virus antibodies in sera and eggs of helmeted guinea fowls (Numida meleagris galeata pallas) in Borno and Yobe States, Nigeria

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    The seroprevalence and maternal antibody profiles to Newcastle disease virus infection of guinea fowls  were studied using haemagglutination inhibition (HI) test, in Borno and Yobe States of Nigeria. Of 822 sera  and 354 egg yolk extracts tested, 327 (39.8%) and 242 (68.4%) were positive for NDV antibodies  respectively. The seroprevalence was significantly higher (P< 0.05) in the dry (47%) than in the rainy  (32.8%) seasons. Maternal antibodies in egg yolk extract (sampled during the rainy season), were  significantly (P< 0.05) higher (68.4%) than the seroprevalence. The frequency distribution of antibody  titers were skewed with 79.8% and 63.2 % of sera and egg yolk respectively having reciprocal antibody  titres ≤ 20. The geometric mean antibody titre was higher (P< 0.05) in the dry season (3.7±2.0) than in  the rainy season (2.5 ±1.7). The geometric mean titre was also higher (P<0.05) in egg (8.9±2.5) than in  sera (3.1±1.9). These results showed that Newcastle disease virus is enzootic among guinea fowls in Borno and Yobe states, especially in the dry season. The geometric mean titer of antibodies from egg yolk (8.9)  was below the protective reciprocal titres ≥35.4, suggesting the need for control measures immediately  after hatching. In addition, birds with titers ≤ 35.4 are partially immune and may shed the virus without a clinical disease when infected thereby becoming a risk to in-contact birds.Keywords: Egg, Guinea fowls, Maternal antibodies Newcastle disease, Seroprevalenc

    Photoluminescence and lasing characteristics of single nonpolar GaN microwires

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    Toxic effect of heavy metals on aquatic environment

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    The indiscriminate discharge of industrial effluents, raw sewage wastes and other waste pollute most of the environments and affect survival and physiological activities of target organisms. Metals in particular have a tendency to accumulate and undergo food chain magnification. Heavy metals affect all groups of organisms and ecosystem processes, including microbial activities. The bioaccumulation of trace elements in living organisms and biomagnification in them describes the processes and pathways of these pollutants from one trophic level to another, exhibiting the higher bioaccumulation ability in the organisms concerned. Some of these organisms, like fishes, are consumed by human beings. They could also cause catastrophic diseases like Minamata and Itai-Itai. Remediation approaches such as excavation and land fill, thermal treatment, electroreclamation and soil capping have been proposed depending on the extension, depth and kind of contamination, but all are expensive and environmentally destructive. Hence, reduction of toxic elements in aquatic environment can be progressively monitored by currently accepted and updated methods.© 2010 International Formulae Group. All rights reserved.Keywords: Heavy metals, effluents, Minamata, Itai-itai, Remediation, antacids

    Effects on the maternofetal unit of the rabbit model after substitution of the amniotic fluid with perfluorocarbons

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    Objectives: Exchanging amniotic fluid (AF) with perfluorocarbon (PFC) may serve as a medium for fetoscopic surgery. This study evaluates the distribution and physiologic effects of intraamniotic PFC as a medium for fetoscopy. Methods: Fetuses of 17 pregnant rabbits underwent either exchange of the AF with PFC, electrolyte solution (ES), or control. The quality of vision during fetoscopy was assessed in AF and PFC. After 6 h, we determined the distribution of PFC in the maternofetal unit. Results: Quality of vision during fetoscopy was better in PFC than with AF. There was no difference in fetal survival between the study groups. PFC was demonstrated on X-ray in the pharynx of 4 fetuses, and the esophagus in 1. Conclusions: PFC provided an ideal medium for fetoscopy without fetal compromise. Copyright (c) 2005 S. Karger AG, Basel

    Cutting tool tracking and recognition based on infrared and visual imaging systems using principal component analysis (PCA) and discrete wavelet transform (DWT) combined with neural networks

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    The implementation of computerised condition monitoring systems for the detection cutting tools’ correct installation and fault diagnosis is of a high importance in modern manufacturing industries. The primary function of a condition monitoring system is to check the existence of the tool before starting any machining process and ensure its health during operation. The aim of this study is to assess the detection of the existence of the tool in the spindle and its health (i.e. normal or broken) using infrared and vision systems as a non-contact methodology. The application of Principal Component Analysis (PCA) and Discrete Wavelet Transform (DWT) combined with neural networks are investigated using both types of data in order to establish an effective and reliable novel software program for tool tracking and health recognition. Infrared and visual cameras are used to locate and track the cutting tool during the machining process using a suitable analysis and image processing algorithms. The capabilities of PCA and Discrete Wavelet Transform (DWT) combined with neural networks are investigated in recognising the tool’s condition by comparing the characteristics of the tool to those of known conditions in the training set. The experimental results have shown high performance when using the infrared data in comparison to visual images for the selected image and signal processing algorithms

    Integrated transcriptional profiling and genomic analyses reveal RPN2 and HMGB1 as promising biomarkers in colorectal cancer

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    Colorectal cancer (CRC) is a heterogeneous disease that is associated with a gradual accumulation of genetic and epigenetic alterations. Among all CRC stages, stage II tumors are highly heterogeneous with a high relapse rate in about 20-25 % of stage II CRC patients following surgery. Thus, a comprehensive analysis of gene signatures to identify aggressive and metastatic phenotypes in stage II CRC is desired for a more accurate disease classification and outcome prediction. By utilizing a Cancer Array, containing 440 oncogenes and tumor suppressors to profile mRNA expression, we identified a larger number of differentially expressed genes in poorly differentiated stage II colorectal adenocarcinoma tissues, compared to their matched normal tissues. Ontology and Ingenuity Pathway Analysis (IPA) indicated that these genes are involved in functional mechanisms associated with several transcription factors. Genomic alterations of these genes were also investigated through The Cancer Genome Atlas (TCGA) database, utilizing 195 published CRC specimens. The percentage of genomic alterations in these genes was ranked based on their mRNA expression, copy number variations and mutations. This data was further combined with published microarray studies from a large set of CRC tumors classified based on prognostic features. This led to the identification of eight candidate genes including RPN2, HMGB1, AARS, IGFBP3, STAT1, HYOU1, NQO1 and PEA15 that were associated with the progressive phenotype. In particular, RPN2 and HMGB1 displayed a higher genomic alteration frequency in CRC, compared to eight other major solid cancers. Immunohistochemistry was performed on additional 78 stage I-IV CRC samples, where RPN2 protein immunostaining exhibited a significant association with stage III/IV tumors, distant metastasis, and poor differentiation, indicating that RPN2 expression is associated with poor prognosis. Further, our study revealed significant transcriptional regulatory mechanisms, networks and gene signatures, underlying CRC malignant progression and phenotype warranting future clinical investigations.published_or_final_versio

    Photocurrent measurements of supercollision cooling in graphene

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    The cooling of hot electrons in graphene is the critical process underlying the operation of exciting new graphene-based optoelectronic and plasmonic devices, but the nature of this cooling is controversial. We extract the hot electron cooling rate near the Fermi level by using graphene as novel photothermal thermometer that measures the electron temperature (T(t)T(t)) as it cools dynamically. We find the photocurrent generated from graphene pnp-n junctions is well described by the energy dissipation rate CdT/dt=A(T3Tl3)C dT/dt=-A(T^3-T_l^3), where the heat capacity is C=αTC=\alpha T and TlT_l is the base lattice temperature. These results are in disagreement with predictions of electron-phonon emission in a disorder-free graphene system, but in excellent quantitative agreement with recent predictions of a disorder-enhanced supercollision (SC) cooling mechanism. We find that the SC model provides a complete and unified picture of energy loss near the Fermi level over the wide range of electronic (15 to \sim3000 K) and lattice (10 to 295 K) temperatures investigated.Comment: 7pages, 5 figure

    Three-loop HTL gluon thermodynamics at intermediate coupling

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    We calculate the thermodynamic functions of pure-glue QCD to three-loop order using the hard-thermal-loop perturbation theory (HTLpt) reorganization of finite temperature quantum field theory. We show that at three-loop order hard-thermal-loop perturbation theory is compatible with lattice results for the pressure, energy density, and entropy down to temperatures T3  TcT\simeq3\;T_c. Our results suggest that HTLpt provides a systematic framework that can used to calculate static and dynamic quantities for temperatures relevant at LHC.Comment: 24 pages, 13 figs. 2nd version: improved discussion and fixing typos. Published in JHE

    Pharmacists in Pharmacovigilance: Can Increased Diagnostic Opportunity in Community Settings Translate to Better Vigilance?

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    The pharmacy profession has undergone substantial change over the last two to three decades. Whilst medicine supply still remains a central function, pharmacist’s roles and responsibilities have become more clinic and patient focused. In the community (primary care), pharmacists have become important providers of healthcare as Western healthcare policy advocates patient self-care. This has resulted in pharmacists taking on greater responsibility in managing minor illness and the delivery of public health interventions. These roles require pharmacists to more fully use their clinical skills, and often involve diagnosis and therapeutic management. Community pharmacists are now, more than ever before, in a position to identify, record and report medication safety incidents. However, current research suggests that diagnostic ability of community pharmacists is questionable and they infrequently report to local or national schemes. The aim of this paper is to highlight current practice and suggest ways in which community pharmacy can more fully contribute to patient safety
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