939 research outputs found

    An EWMA Control Chart for Monitoring the Mean of Skewed Populations Using Weighted Variance.

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    This paper discusses the use of weighted variance (wv) in setting up the limits of the exponentially weighted moving average (EWMA) chart for the monitoring of the mean of a process from a skewed population. This chart, called the WV-EWMA chart hereafter, reduces to the standard EWMA chart when the underlying distribution is symmetric

    Influence of gas flow rate on liquid distribution in trickle-beds using perforated plates as liquid distributors

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    Two wire mesh tomography devices and a liquid collector were used to study the influence of the gas flow rate on liquid distribution when fluids distribution on top of the reactor is ensured by a perforated plate. In opposition to most of the studies realized by other authors, conditions in which the gas has a negative impact in liquid distribution were evidenced. Indeed, the obtained results show that the influence of gas flow rate depends on the quality of the initial distribution, as the gas forces the liquid to "respect" the distribution imposed at the top of the reactor. Finally, a comparison between the two measuring techniques shows the limitations of the liquid collector and the improper conclusions to which its use could lead

    A Study On The Performances Of Mewma And Mcusum Charts For Skewed Distributions.

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    A multivariate chart, instead of separate univariate charts is used for a joint monitoring of several correlated variables

    A Comparison Of The Performances Of Various Single Variable Charts.

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    Control charts are used for process monitoring and improvement in industries. Two charts are usually used in the monitoring of both the mean and variance separately

    Statistical Modeling of EMG Signal

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    The aim of this research is to measure and build a statistical model of EMG signals . A linear regression method was applied as a statistical modeling method ,the common types of linear regression models was explored. The electromyography (EMG) was measured from the two hands of a person as a way to perform noise reduction with the use of XOR logical operation facilities . To measure EMG signals, the research used six OLIMEXnbsp EMG shield , controllednbsp by Arduino 328 control board , a new classification and modeling of EMG signals of 5 movements of an arm are presented. One of the six channelsnbsp used for the EMGnbsp measurements was used as anbsp reference channel , while the remaining as a measuring channels . The resultantnbsp EMG of each channel was considered as an independent variable (emg)nbsp for the linear regression model and the movement angle (degree) as a dependent variable for the model

    High Avidity dsDNA Autoantibodies in Brazilian Women with Systemic Lupus Erythematosus: Correlation with Active Disease and Renal Dysfunction

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    We investigated in Brazilian women with SLE the prevalence and levels of high avidity (HA) dsDNA antibodies and tested their correlation with lupus activity and biomarkers of renal disease. We also compared these correlations to those observed with total dsDNA antibodies and antibodies against nucleosome (ANuA). Autoantibodies were detected by ELISA, while C3 and C4 levels were determined by nephelometry. Urine protein/creatinine ratio was determined, and lupus activity was measured by SLEDAI-2K. The prevalence of total and HA dsDNA antibodies was similar to but lower than that verified for ANuA. The levels of the three types of antibodies were correlated, but the correlation was more significant between HA dsDNA antibodies and ANuA. High avidity dsDNA antibodies correlated positively with ESR and SLEDAI and inversely with C3 and C4. Similar correlations were observed for ANuA levels, whereas total dsDNA antibodies only correlated with SLEDAI and C3. The levels of HA dsDNA antibodies were higher in patients with proteinuria, but their levels of total dsDNA antibodies and ANuA were unaltered. High avidity dsDNA antibodies can be found in high prevalence in Brazilian women with SLE and are important biomarkers of active disease and kidney dysfunction

    Breast lesions and cancer: histopathology and molecular classification in a referral hospital in Ghana

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    Background: Histological diagnosis is crucial to the management of breast diseases. It determines the kind of disease, the treatment modalities, and the outcome of management. Our department receives breast biopsies from the northern sector of Ghana constituting over 50% of the Ghanaian population. This study aimed at elucidating the pattern of disease and associated traditional prognostic indices of breast cases in our department over a period of 9 years.Methods: Information on the demographic characteristics and the histological diagnoses made on all breast cases received and processed in the department were accessed and entered into an Excel spreadsheet. Slides were reviewed and IHC was done on suitable cases. Descriptive statistics were generated using IMB-SPSS version 23.Results: A total of 4276 breast cases were received by the department within the study period, with 97.6% being female. Age ranged (female/male) from 10 to 98/13 to 102 years, with mean ages of 38.2 years (SD ± 16.7) and 41.15 years (SD ± 21.6), respectively. Cases were evenly distributed in both left and right breasts and 4.3% were bilateral. Inflammatory conditions were seen in 7.5% of cases. The most diagnosed benign tumor was fibroadenoma (54%), followed by fibrocystic change (8.1%). Gynecomastia was diagnosed in 66.3% of males. Malignant cases were 38.6%, with invasive carcinoma NST being the most frequent (87.5%). Histological grades were I = 9.4%, II = 41.6%, and III = 49%. Molecular subtypes were luminal A (19.8%), luminal B (9.9%), Her2 (16%), and TNBC (54.3%).Conclusion: Our findings show an increase in breast cancer cases compared to previous studies in our center, suggesting increased awareness and improved diagnosis. However, this increase is consistent with most studies in sub-Saharan Africa

    Electronic structure and magnetic state of transuranium metals under pressure

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    Electronic structure of bcc Np, fcc Pu, Am, and Cm pure metals under pressure has been investigated employing the LDA+U method with spin-orbit coupling (LDA+U+SO). Magnetic state of the actinide ions was analyzed in both LS and jj coupling schemes to reveal the applicability of corresponding coupling bases. It was demonstrated that whereas Pu and Am are well described within the jj coupling scheme, Np and Cm can be described appropriately neither in {m-sigma}, nor in {jmj} basis, due to intermediate coupling scheme realizing in these metals that requires some finer treatment. The LDA+U+SO results for the considered transuranium metals reveal bands broadening and gradual 5f electron delocalization under pressure.Comment: 5 pages, 5 figure

    Finite size scaling in the solar wind magnetic field energy density as seen by WIND

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    Statistical properties of the interplanetary magnetic field fluctuations can provide an important insight into the solar wind turbulent cascade. Recently, analysis of the Probability Density Functions (PDF) of the velocity and magnetic field fluctuations has shown that these exhibit non-Gaussian properties on small time scales while large scale features appear to be uncorrelated. Here we apply the finite size scaling technique to explore the scaling of the magnetic field energy density fluctuations as seen by WIND. We find a single scaling sufficient to collapse the curves over the entire investigated range. The rescaled PDF follow a non Gaussian distribution with asymptotic behavior well described by the Gamma distribution arising from a finite range Lévy walk. Such mono scaling suggests that a Fokker-Planck approach can be applied to study the PDF dynamics. These results strongly suggest the existence of a common, nonlinear process on the time scale up to 26 hours
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