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1
Sim, Myounghwa. "Realized Skewness and the Return Predictability". Journal of Derivatives and Quantitative Studies 24, n. 1 (29 febbraio 2016): 119–52. http://dx.doi.org/10.1108/jdqs-01-2016-b0005.
Testo completoAbstract (sommario):
We explore the cross-section of realized variance, skewness, and kurtosis for stock returns obtained from intraday data. We investigate the properties of the realized higher moments, and more importantly, examine relations between the realized moments and subsequent stock returns. We find evidence of a negative relation between realized skewness and next week’s returns. A strategy buying stocks in the lowest realized skewness quintile and selling stocks in the highest realized skewness quintile earns 0.79 percent per week a risk-adjusted basis. Our results on the realized skewness are robust to controls for various firm characteristics such as size and book-to-market. Little evidence exists that either the realized volatility or the realized kurtosis is significantly related to next week’s returns.
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Chaudhary, Rashmi, Dheeraj Misra e Priti Bakhshi. "Conditional relation between return and co-moments – an empirical study for emerging Indian stock market". Investment Management and Financial Innovations 17, n. 2 (2 luglio 2020): 308–19. http://dx.doi.org/10.21511/imfi.17(2).2020.24.
Testo completoAbstract (sommario):
Due to many theoretical and practical shortcomings of the traditional CAPM model, this study aims at analyzing the CAPM with possible extensions. The analysis aims to know the empirical soundness of Conditional Higher Moment CAPM in emerging India’s capital market. The sample consists of 69 company’s daily stock price data from April 2004 to March 2019 from NSE 100. Panel data analysis is used on 21 cross-sections. The overall results show that when both up and down markets are incorporated separately, all three moments, namely, co-variance, co-skewness, and co-kurtosis, are priced during the normal Indian economy phase. Further, this study states that including higher moments (co-skewness and co-kurtosis) in the two-moment model provides symmetry in both the up and down markets. This is one of the first studies in the Indian Stock market explaining the variation in portfolio returns through panel data analysis by extending CAPM with conditional higher-order co-moments. The portfolio managers should consider skewness and kurtosis along with variance in constructing the optimal portfolios.
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Wampler, Taylor, e Andre C. Barato. "Skewness and kurtosis in stochastic thermodynamics". Journal of Physics A: Mathematical and Theoretical 55, n. 1 (9 dicembre 2021): 014002. http://dx.doi.org/10.1088/1751-8121/ac3b0c.
Testo completoAbstract (sommario):
Abstract The thermodynamic uncertainty relation is a prominent result in stochastic thermodynamics that provides a bound on the fluctuations of any thermodynamic flux, also known as current, in terms of the average rate of entropy production. Such fluctuations are quantified by the second moment of the probability distribution of the current. The role of higher order standardized moments such as skewness and kurtosis remains largely unexplored. We analyze the skewness and kurtosis associated with the first passage time of thermodynamic currents within the framework of stochastic thermodynamics. We develop a method to evaluate higher order standardized moments associated with the first passage time of any current. For systems with a unicyclic network of states, we conjecture upper and lower bounds on skewness and kurtosis associated with entropy production. These bounds depend on the number of states and the thermodynamic force that drives the system out of equilibrium. We show that these bounds for skewness and kurtosis do not hold for multicyclic networks. We discuss the application of our results to infer an underlying network of states.
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Miranda, Rodrigo A., Adriane B. Schelin, Abraham C. L. Chian e José L. Ferreira. "Non-Gaussianity and cross-scale coupling in interplanetary magnetic field turbulence during a rope–rope magnetic reconnection event". Annales Geophysicae 36, n. 2 (23 marzo 2018): 497–507. http://dx.doi.org/10.5194/angeo-36-497-2018.
Testo completoAbstract (sommario):
Abstract. In a recent paper (Chian et al., 2016) it was shown that magnetic reconnection at the interface region between two magnetic flux ropes is responsible for the genesis of interplanetary intermittent turbulence. The normalized third-order moment (skewness) and the normalized fourth-order moment (kurtosis) display a quadratic relation with a parabolic shape that is commonly observed in observational data from turbulence in fluids and plasmas, and is linked to non-Gaussian fluctuations due to coherent structures. In this paper we perform a detailed study of the relation between the skewness and the kurtosis of the modulus of the magnetic field |B| during a triple interplanetary magnetic flux rope event. In addition, we investigate the skewness–kurtosis relation of two-point differences of |B| for the same event. The parabolic relation displays scale dependence and is found to be enhanced during magnetic reconnection, rendering support for the generation of non-Gaussian coherent structures via rope–rope magnetic reconnection. Our results also indicate that a direct coupling between the scales of magnetic flux ropes and the scales within the inertial subrange occurs in the solar wind. Keywords. Space plasma physics (turbulence)
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KUMAR, DEVENDRA, SANKU DEY, MAZEN NASSAR e PREETI YADAV. "The recurrence relations of order statistics moments for power Lomax distribution". Journal of Statistical Research 52, n. 1 (2 settembre 2018): 75–90. http://dx.doi.org/10.47302/jsr.2018520105.
Testo completoAbstract (sommario):
The power Lomax distribution due to Rady et al. (2016) is an alternative to and provides better fits for bladder cancer data (Lee and Wang, 2003) than the Lomax, exponential Lo- max, Weibull Lomax, extended Poisson Lomax and beta Lomax distributions. Exact explicit expressions as well as recurrence relations for the single and double (product) moments have been derived from the power Lomax distribution. These recurrence relations enable computation of the mean, variance, skewness and kurtosis of all order statistics for all sample sizes in a simple and efficient manner. By using these relation, the mean, variance, skewness and kurtosis of order statistics for sample sizes up to 5 for various values of shape and scale parameters are tabulated. Finally, remission times (in months) of bladder cancer patients have been analyzed to show how the proposed relations work in practice.
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Zhang, Jingyan, Jan De Spiegeleer e Wim Schoutens. "Implied Tail Risk and ESG Ratings". Mathematics 9, n. 14 (8 luglio 2021): 1611. http://dx.doi.org/10.3390/math9141611.
Testo completoAbstract (sommario):
This paper explores whether the high or low ESG rating of a company is related to the level of its implied tail risk, measured on the basis of derivative data by implied skewness and implied kurtosis. Previous research suggests that the ESG rating of a company is indeed connected to some financial risk; however, often, only volatility is used as a risk measure. We examined the relation between ESG ratings and implied volatility, and explore the relation between ESG ratings and financial risk in more depth by looking into higher implied moments accessing financial tail risk. First, we found that higher ESG rated companies have a lower implied volatility connected with them, and exhibit more negative implied skewness and higher implied kurtosis. In other words, we observed a higher negative tail risk for higher ESG rated companies. However, on a midsized company data set, we found that higher ESG rated companies both have lower implied volatility, and exhibit less negative implied skewness and lower implied kurtosis. Hence, negative tail risk is typically lower for high ESG rated companies. Our study further investigated similar effects on individual environmental (E), social (S) and governance (G) scores of the involved companies. Second, we examined whether such a kind of trend exists for different sectors. Our results indicate that the influence of ESG ratings on implied volatility exhibits a similar trend, except for the industrial, information services, and real estate sectors, while for the materials, healthcare, and communication services sectors, the influence of ESG ratings on implied skewness and implied kurtosis is less pronounced. Moreover, the results show that the ESG ratings are correlated with implied moments for companies in consumer discretionary sectors.
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Chaudhary, Rashmi, Priti Bakhshi e Hemendra Gupta. "The performance of the Indian stock market during COVID-19". Investment Management and Financial Innovations 17, n. 3 (16 settembre 2020): 133–47. http://dx.doi.org/10.21511/imfi.17(3).2020.11.
Testo completoAbstract (sommario):
The current empirical study attempts to analyze the impact of COVID-19 on the performance of the Indian stock market concerning two composite indices (BSE 500 and BSE Sensex) and eight sectoral indices of Bombay Stock Exchange (BSE) (Auto, Bankex, Consumer Durables, Capital Goods, Fast Moving Consumer Goods, Health Care, Information Technology, and Realty) of India, and compare the composite indices of India with three global indexes S&P 500, Nikkei 225, and FTSE 100. The daily data from January 2019 to May 2020 have been considered in this study. GLS regression has been applied to assess the impact of COVID-19 on the multiple measures of volatility, namely standard deviation, skewness, and kurtosis of all indices. All indices’ key findings show lower mean daily return than specific, negative returns in the crisis period compared to the pre-crisis period. The standard deviation of all the indices has gone up, the skewness has become negative, and the kurtosis values are exceptionally large. The relation between indices has increased during the crisis period. The Indian stock market depicts roughly the same standard deviation as the global markets but has higher negative skewness and higher positive kurtosis of returns, making the market seem more volatile.
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Einasto, Jaan, Anatoly Klypin, Gert Hütsi, Lauri-Juhan Liivamägi e Maret Einasto. "Evolution of skewness and kurtosis of cosmic density fields". Astronomy & Astrophysics 652 (agosto 2021): A94. http://dx.doi.org/10.1051/0004-6361/202039999.
Testo completoAbstract (sommario):
Aims. We investigate the evolution of the one-point probability distribution function (PDF) of the dark matter density field and the evolution of its moments for fluctuations that are Gaussian in the linear regime. Methods. We performed numerical simulations of the evolution of the cosmic web for the conventional ΛCDM model. The simulations covered a wide range of box sizes L = 256 − 4000 h−1 Mpc, mass, and force resolutions, and epochs from very early moments z = 30 to the present moment z = 0. We calculated density fields with various smoothing lengths to determine the dependence of the density field on the smoothing scale. We calculated the PDF and its moments variance, skewness, and kurtosis. We determined the dependence of these parameters on the evolutionary epoch z, on the smoothing length Rt, and on the rms deviation of the density field σ using a cubic-cell and top-hat smoothing with kernels 0.4 h−1 Mpc ≤ Rt ≤ 32 h−1 Mpc. Results. We focus on the third (skewness S) and fourth (kurtosis K) moments of the distribution functions: their dependence on the smoothing scale Rt, the amplitude of the fluctuations σ, and the redshift z. Moments S and K, calculated for density fields at different cosmic epochs and smoothed with various scales, characterise the evolution of different structures of the web. Moments calculated with small-scale smoothing (Rt ≈ (1 − 4) h−1 Mpc) characterise the evolution of the web on cluster-type scales. Moments found with strong smoothing (Rt ≳ (5 − 15) h−1 Mpc) describe the evolution of the web on supercluster scales. During the evolution, the reduced skewness S3 = S/σ and reduced kurtosis S4 = K/σ2 present a complex behaviour: at a fixed redshift, curves of S3(σ) and S4(σ) steeply increase with σ at σ ≲ 1 and then flatten out and become constant at σ ≳ 2. When we fixed the smoothing scale Rt, the curves at large σ started to gradually decline after reaching the maximum at σ ≈ 2. We provide accurate fits for the evolution of S3, 4(σ, z). Skewness and kurtosis approach constant levels at early epochs S3(σ)≈3 and S4(σ)≈15. Conclusions. Most of the statistics of dark matter clustering (e.g. halo mass function or concentration-mass relation) are nearly universal: they mostly depend on the σ with a relatively modest correction to apparent dependence on the redshift. We find just the opposite for skewness and kurtosis: the dependence of the moments on the evolutionary epoch z and smoothing length Rt is very different. Together, they uniquely determine the evolution of S3, 4(σ). The evolution of S3 and S4 cannot be described by current theoretical approximations. The often used lognormal distribution function for the PDF fails to even qualitatively explain the shape and evolution of S3 and S4.
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Wang, Xiao Bo, Chuan Sheng Wang e De Wei Zhang. "Development of Carton Black’s Dispersion Evaluation System Based on Statistics". Advanced Materials Research 221 (marzo 2011): 684–88. http://dx.doi.org/10.4028/www.scientific.net/amr.221.684.
Testo completoAbstract (sommario):
Digitization of carton’s dispersion is important for rubber researching. In statistics, kurtosis and skewness can been used to evaluate the dispersion, control chart can been used to decrease the influence of abnormal factors. The application of computer technology can finish calculating and showing of statistical data quickly and exactly. Digitization of distribution supplies more ways to research the relation between carton’s dispersion and rubber’s property.
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Mesimeri, M., V. Karakostas, E. Papadimitriou e G. Tsaklidis. "CHARACTERISTICS OF SEISMIC EXCITATIONS IN CORINTH GULF (GREECE)". Bulletin of the Geological Society of Greece 50, n. 3 (27 luglio 2017): 1379. http://dx.doi.org/10.12681/bgsg.11851.
Testo completoAbstract (sommario):
Seismic excitations occur as mainshock-aftershock sequences (MS-AS) encompassing a strong event called mainshock with the largest magnitude in the set, or as earthquake swarms (ES) when a distinctive main event is absent. In regions as the gulf of Corinth, where active deformation is manifested with frequent seismicity bursts, it is important to distinguish MS-AS from ES for providing information on the physical process of earthquake generation and contribute to the seismic hazard assessment. For this purpose, a highly accurate local earthquake catalogue was compiled and an effort was made for clusters identification after establishing certain criteria based on spatio-temporal seismicity properties. The skewness and kurtosis of moment release history were calculated considering the normalized time of every event in a cluster since the starting time of the cluster and its seismic moment. For MS-AS we found large positive values for skewness and kurtosis contrary to ES that exhibit negative to low positive values for skewness and even lower values for kurtosis.In order to verify the classification of clusters, the b-value, the spatial size and the number of events of each cluster were examined. Finally, a scaling relation between the length of the rupture zone and magnitude derived for the MS-AS sequences.
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Fernandes, Anderson Rocha de J., Simone Evangelista Fonseca e Robert Aldo Iquiapaza. "Performance measurement models and their influence on net fundraising of investment funds". Revista Contabilidade & Finanças 29, n. 78 (18 giugno 2018): 435–51. http://dx.doi.org/10.1590/1808-057x201805330.
Testo completoAbstract (sommario):
ABSTRACT This article aims to analyze the relation between third- and fourth-order conditions and risk factors and their adequacy to return, performance, and net fundraising. The factors used to determine fund performance and, consequently, their relation with fundraising are: market return, size, book-to-market, profitability, investment, co-skewness, and co-kurtosis. The funds constituting the sample are those classified as Free Stocks (within the period from April 2001 to April 2015). Methodologically, this study has two phases. The first one refers to estimating the parameters that represent fund sensitivity to the factors and the comparison of the capital asset pricing models (CAPM), Fama-French-Carhart 4-factor (FFC), Fama-French 5-factor (FF5), Fama-French 5-factor with momentum (FF5M), added or not with co-moments, by means of the fixed-effects procedure. The second one deals with verifying the relation between performance and net fundraising. The models were reestimated through moving time windows, so that the alpha calculated on each of them represented fund performance within the immediately subsequent period. We also estimated the relation fundraising-performance through cross-section regressions, with rates and age as control variables. The results showed that the co-skewness and co-kurtosis coefficients are not that relevant for determining performance and net fundraising of investment funds. Among the risk factors, market, size, and momentum are the significant parameters for fund returns. The FFC and FF5M models are those with greater explanatory power regarding return specification. There is also evidence of convexity in the relation between performance and fundraising.
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Marchetti, P., C. Grossi, R. Giannarelli, A. Masoni, R. Cristofani, M. Giannecchini e R. Navales. "Salivary immunoreactive insulin: a new entry in clinical chemistry?" Clinical Chemistry 34, n. 7 (1 luglio 1988): 1478–80. http://dx.doi.org/10.1093/clinchem/34.7.1478.
Testo completoAbstract (sommario):
Abstract The distribution of salivary immunoreactive insulin (S-IRI) and its relation to plasma insulin (P-IRI) and other clinical and metabolic variables were investigated in 93 nondiabetic subjects (60 males, 33 females, ages 11-70 y). S-IRI was measured by RIA, with monoiodinated insulin as labeled antigen and with standards consisting of serial dilutions in saliva of known amounts of native insulin. The sensitivity of the method was 12.1 pmol/L. The intra- and between-assay CVs were near 10%, and analytical recovery exceeded 93% for various insulin concentrations added to saliva. S-IRI, measured after overnight fast, showed a nonguassian distribution in males (skewness 1.18, kurtosis 1.41) and females (skewness 1.71, kurtosis 1.18); mean and median values were higher in males (14.3 and 12.1 nmol/min) than in females (12.1 and 7.15 nmol/min), but not significantly so. S-IRI was significantly correlated with P-IRI both in males (r = 0.75, P less than 0.0001) and females (r = 0.72, P less than 0.0001). These results, particularly the correlation between S-IRI and P-IRI, indicate the possibility of using S-IRI measurement in clinical practice.
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Sura, Philip, e Maxime Perron. "Extreme Events and the General Circulation: Observations and Stochastic Model Dynamics". Journal of the Atmospheric Sciences 67, n. 9 (1 settembre 2010): 2785–804. http://dx.doi.org/10.1175/2010jas3369.1.
Testo completoAbstract (sommario):
Abstract This study explores the dynamical role of non-Gaussian potential vorticity variability (extreme events) in the zonally averaged circulation of the atmosphere within a stochastic framework. First the zonally averaged skewness and kurtosis patterns of relative and potential vorticity anomalies from NCEP–NCAR reanalysis data are presented. In the troposphere, midlatitude regions of near-zero skewness coincide with regions of maximum variability. Equatorward of the Northern Hemisphere storm track positive relative/potential vorticity skewness is observed. Poleward of the same storm track the vorticity skewness is negative. In the Southern Hemisphere the relation is reversed, resulting in negative relative/potential vorticity skewness equatorward, and positive skewness poleward of the storm track. The dynamical role of extreme events in the zonally averaged general circulation is then explored in terms of the potential enstrophy budget by linking eddy enstrophy fluxes to a stochastic representation of non-Gaussian potential vorticity anomalies. The stochastic model assumes that potential vorticity anomalies are advected by a random velocity field. The assumption of stochastic advection allows for a closed expression of the meridional enstrophy flux: the potential enstrophy flux is proportional to the potential vorticity skewness. There is some evidence of this relationship in the observations. That is, potential enstrophy fluxes might be linked to non-Gaussian potential vorticity variability. Thus, extreme events may presumably play an important role in the potential enstrophy budget and the related general circulation of the atmosphere.
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Mohri, Satoshi, Juichiro Shimizu, Gentaro Iribe, Haruo Ito, Terumasa Morita, Hiroki Yamaguchi, Shunji Sano, Fumihiko Kajiya e Hiroyuki Suga. "Normal distribution of ventricular pressure-volume area of arrhythmic beats under atrial fibrillation in canine heart". American Journal of Physiology-Heart and Circulatory Physiology 288, n. 4 (aprile 2005): H1740—H1746. http://dx.doi.org/10.1152/ajpheart.00584.2004.
Testo completoAbstract (sommario):
We previously found the frequency distribution of the left ventricular (LV) effective afterload elastance (Ea) of arrhythmic beats to be nonnormal or non-Gaussian in contrast to the normal distribution of the LV end-systolic elastance (Emax) in canine in situ LVs during electrically induced atrial fibrillation (AF). These two mechanical variables determine the total mechanical energy [systolic pressure-volume area (PVA)] generated by LV contraction when the LV end-diastolic volume is given on a per-beat basis. PVA and Emax are the two key determinants of the LV O2 consumption per beat. In the present study, we analyzed the frequency distribution of PVA during AF by its χ2, significance level, skewness, and kurtosis and compared them with those of other major cardiodynamic variables including Ea and Emax. We assumed the volume intercept (V0) of the end-systolic pressure-volume relation needed for Emax determination to be stable during arrhythmia. We found that PVA distributed much more normally than Ea and slightly more so than Emax during AF. We compared the χ2, significance level, skewness, and kurtosis of all the complex terms of the PVA formula. We found that the complexity of the PVA formula attenuated the effect of the considerably nonnormal distribution of Ea on the distribution of PVA along the central limit theorem. We conclude that mean (SD) of PVA can reliably characterize the distribution of PVA of arrhythmic beats during AF, at least in canine hearts.
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BANERJEE, ARINDAM. "Risk Return Analysis of FTSE Listed Select Stocks with FTSE100 Index". Journal of Accounting, Business and Management (JABM) 30, n. 2 (4 novembre 2023): 59. http://dx.doi.org/10.31966/jabminternational.v30i2.962.
Testo completoAbstract (sommario):
This paper analyses the stock returns of FTSE 100 and a sample of selected companies within the index to determine the existence of interdependence and magnitude of the same. The companies are selectively chosen from certain primary sectors based on their influence on the economy. The idea is to understand if large firms have significant effect on the index. The study involves statistical analysis representing data over a 10-year period spanning 1st November 2011 to 31st October 2021), the data points include adjusted closing values of the index and the selected companies. Correlation and regression analysis is performed by taking the index as the dependent variable and the companies as the independent variable. The results are then analyzed from a variety of perspectives including Skewness, Kurtosis, Correlation Coefficients and Coefficient of Determination. Skewness and Kurtosis reveals the performance of returns as compared to the average. The results of the study reveal a net positive correlation is observed between the index and the companies. additionally, the regression analysis results showcase how certain sectors like defense have a significant relation with the index while others like supermarkets do not. Other interesting facts uncovered relate to how a certain cluster of firms compare as opposed to a single firm when analyzed in conjunction with the index. The results are summarized to come up with a conclusion on the relationship an index has with its constituents.
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Sattin, F., M. Agostini, R. Cavazzana, G. Serianni, P. Scarin e N. Vianello. "About the parabolic relation existing between the skewness and the kurtosis in time series of experimental data". Physica Scripta 79, n. 4 (31 marzo 2009): 045006. http://dx.doi.org/10.1088/0031-8949/79/04/045006.
Testo completo
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Ausloos, Marcel, e Roy Cerqueti. "Intriguing yet simple skewness: kurtosis relation in economic and demographic data distributions, pointing to preferential attachment processes". Journal of Applied Statistics 45, n. 12 (15 dicembre 2017): 2202–18. http://dx.doi.org/10.1080/02664763.2017.1413077.
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Shankar, S., T. Mohanraj e A. Pramanik. "Tool Condition Monitoring While Using Vegetable Based Cutting Fluids During Milling of Inconel 625". Journal of Advanced Manufacturing Systems 18, n. 04 (19 novembre 2019): 563–81. http://dx.doi.org/10.1142/s0219686719500306.
Testo completoAbstract (sommario):
This investigation has designed a tool condition monitoring system (TCM) while milling of Inconel 625 based on sound and vibration signatures. The experiments were carried out based on response surface methodology (RSM) central composite design, design of experiments. The process parameters such as speed, feed, depth of cut and vegetable-based cutting fluids were optimized based on surface roughness, flank wear. It was found that the sound pressure and vibration signatures have the direct relation with flank wear. The statistical features like root mean square, skewness, kurtosis and mean values were extracted from the experimental data. From the designed NN estimator, the cutting tool flank wear was predicted with the mean square error (MSE) of 0.084212.
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Ansari Fard, Mohammad, Zahra Baghkhani, Laya Ghodsi, Sina Taamoli, Farbod Hassani e Shant Baghram. "Structure of cosmic web in non-linear regime: the nearest neighbour and spherical contact distributions". Monthly Notices of the Royal Astronomical Society 512, n. 4 (4 febbraio 2022): 5165–82. http://dx.doi.org/10.1093/mnras/stac256.
Testo completoAbstract (sommario):
ABSTRACT In non-linear scales, the matter density distribution is not Gaussian. Consequently, the widely used two-point correlation function is not adequate anymore to capture the matter density field’s entire behaviour. Among all statistics beyond correlation functions, the spherical contact (or equivalently void function), and nearest neighbour distribution function seem promising tools to probe matter distribution in non-linear regime. In this work, we use haloes from cosmological N-body simulations, galaxy groups from the volume-limited galaxy group and central galaxies from mock galaxy catalogues, to compare the spherical contact with the nearest neighbour distribution functions. We also calculate the J-function (or equivalently the first conditional correlation function), for different samples. Moreover, we consider the redshift evolution and mass-scale dependence of statistics in the simulations and dependence on the magnitude of volume-limited samples in group catalogues as well as the mock central galaxies. The shape of the spherical contact probability distribution function is nearly skew-normal, with skewness and kurtosis being approximately 0.5 and 3, respectively. On the other hand, the nearest neighbour probability distribution function is nearly lognormal, with logarithmic skewness and kurtosis being approximately 0.1 and 2.5, respectively. Accordingly, the spherical contact distribution function probes larger scales compared to the nearest neighbour distribution function, which is influenced by details of structures. We also find a linear relation between the mean and variance of the spherical contact probability distribution function in simulations and mock galaxies, which could be used as a distinguishing probe of cosmological models.
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Wang, Lei, Binzhen Zhou, Peng Jin, Jinxuan Li, Shuxue Liu e Guillaume Ducrozet. "Relation between occurrence probability of freak waves and kurtosis/skewness in unidirectional wave trains under single-peak spectra". Ocean Engineering 248 (marzo 2022): 110813. http://dx.doi.org/10.1016/j.oceaneng.2022.110813.
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Guszejnov, Dávid, Nóra Lazányi, Attila Bencze e Sándor Zoletnik. "On the effect of intermittency of turbulence on the parabolic relation between skewness and kurtosis in magnetized plasmas". Physics of Plasmas 20, n. 11 (novembre 2013): 112305. http://dx.doi.org/10.1063/1.4835535.
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Tušek, Kristina, Ivana Buntak, Jaseka Gajdoš Kljusurić e Ana Jurinjak Tušek. "Gender specific differences of the ethanol and nicotine toxicity verified by the use of mathematical models". Croatian journal of food science and technology 11, n. 1 (31 maggio 2019): 76–87. http://dx.doi.org/10.17508/cjfst.2019.11.1.11.
Testo completoAbstract (sommario):
Beside the pandemic of obesity, the binge drinking becomes a huge problem. The toxicity of consuming alcohol and smoking in the late adolescent population was examined using mathematical models. The body was divided into compartments for two different models; (i) the ethanol model (4 compartments: central compartment, muscle and fat compartment, liver compartment and gastrointestinal compartment) and (ii) the nicotine model (2 compartments: liver compartment and central compartment). Different alcohol contents simulated consumptions of 90 mL of spirits; 900 mL of beer or 600 mL of wine. Nicotine metabolism simulation was performed for three different initial doses of nicotine (light, medium and strong cigarettes). Significant differences are observed regarding the gender; where the maximum ethanol concentration is reached at 0.5 h (males: 27 mmol/dm3 and females: 33 mmol/dm3) in the gastrointestinal compartment while complete nicotine degradation in the liver takes approximately 10 h and in the central compartment 15 h, respectively. The skewness and kurtosis of the toxin concentrations showed their relation with the symmetry of the toxin retention in the body. Results show preferable positively skewed distribution which implies a shorter retention time in the organism while higher kurtosis implies higher toxin concentration.
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Alberico, Ines, e Francesca Budillon. "A Quantitative Evaluation of Hyperpycnal Flow Occurrence in a Temperate Coastal Zone: The Example of the Salerno Gulf (Southern Italy)". Geosciences 9, n. 12 (28 novembre 2019): 501. http://dx.doi.org/10.3390/geosciences9120501.
Testo completoAbstract (sommario):
The inner continental shelf is regarded as a repository of hyperpycnal flow (HF) deposits the analysis of which may contribute to hydrogeological risk assessment in coastal areas. In line with the source to sink paradigm, we examined the dynamics of the coastal watersheds facing the Salerno Gulf (Southern Tyrrhenian Sea) in generating hyperpycnal flows and investigated the shallow marine sediment record to verify their possible occurrence in the recent past. Thus, the morphometric properties (hypsometric integral, hypsometric skewness, hypsometric kurtosis, density skewness and density kurtosis) of the watersheds together with the potential rivers’ discharge and sediment concentration, calculated by applying altitude- and extent -based experimental relations, allowed to detect the rivers that were prone to producing HFs. In the shallow marine environment record of the last 2 kyr, anomalous sedimentation, possibly linked to HF events, was identified by comparing the sand-mud ratio (S/M) down-core —at three sites off the main river mouths — to the expected S/M calculated by applying the relation governing the present-day distribution of sand at the seabed in the Salerno Gulf. A return period of major HF events ≤ 0.1 kyr can be inferred for rivers which fall into the category “dirty rivers”. In these cases, the watersheds have a hypsometric index ranging between 0.2 and 0.3, coastal plains not exceeding 30% of the entire catchment area and a maximum topographic height ≥1000 m. A return period of about 0.3 kyr has been inferred for the “moderately dirty rivers”. In these other cases, about 50% of the watersheds develop into a low gradient coastal plain and have a hypsometric index ranging between 0.09 and 0.2. The observations on land and offshore have been complemented to reach a more comprehensive vision of the coastal area dynamics. The method here proposed corroborates the effectiveness of the source to sink approach and is applicable to analogous sediment records in temperate continental shelves which encompass the last 3 kyr, a time interval in which the oscillations of relative sea level can be overlooked.
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Kumar, Devender. "EMPOWERMENT AMONG GIRLS’ STUDYING IN SENIOR SECONDARY SCHOOLS IN RELATION TO THEIR PARENTAL RELATIONSHIP". SCHOLARLY RESEARCH JOURNAL FOR HUMANITY SCIENCE AND ENGLISH LANGUAGE 10, n. 49 (31 ottobre 2021): 12098–106. http://dx.doi.org/10.21922/srjhsel.v10i49.9750.
Testo completoAbstract (sommario):
The present study provides knowledge and information about the empowerment level of girls and also its relationship with their parents. There is lack of researches in this area of girls’ empowerment especially with regard to their parental relationship. Empowered women lead to economic development and social progress of the nation. The study is helpful to the teachers, policy makers, bureaucrats, researchers, scholars, educators, and politicians because it gives understanding of how relationship of parents helps the girls’ in their empowerment. The present study was conducted through the survey method under descriptive method of research. Survey studies are conducted to collect detailed description of existing phenomenon with the intent of employing data justify current condition practices or to make more intelligent. A representative sample of 316 girls studying in class 10+1 and 10+2 was selected by using multistage random sampling technique Research Tools Used In order to collect the requisite data, following research tools were used. The data on empowerment among girls’ was verified for normality by calculating certain statistics like mean, median, mode, standard deviation, quartile deviation, kurtosis and skewness.
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Cargnelutti Filho, Alberto, Daniela Lixinski Silveira, Valéria Escaio Bubans, Bruno Fillipin Osmari, Felipe Manfio Somavilla, Vithória Morena Ortiz e Lucas Fillipin Osmari. "SAMPLE SIZE AND LINEAR RELATIONS IN SLENDER LEAF RATTLEBOX". REVISTA DE AGRICULTURA NEOTROPICAL 9, n. 2 (2 giugno 2022): e6834. http://dx.doi.org/10.32404/rean.v9i2.6834.
Testo completoAbstract (sommario):
Objectives of this work were to determine the sample size (number of plants) to estimate the mean of slender leaf rattlebox (Crotalaria ochroleuca) traits and investigate the relations among traits. In an experimental area of 8 m × 20 m (160 m2), at 147 days after sowing, 110 plants were randomly selected. The following traits were evaluated for each plant: plant height, stem diameter, number of nodes, number of leaves, leaf fresh matter, stem fresh matter, shoot fresh matter, leaf dry matter, stem dry matter and shoot dry matter. Measures of central tendency, variability, skewness and kurtosis were calculated. Normality was verified using the Kolmogorov-Smirnov test and the sample size was calculated to estimate the mean of the traits, assuming estimation errors (semi-amplitudes of the 95% confidence interval) equal to 1%, 2%, …, 30% of the mean. The relations among traits were investigated by scatter plots, correlation and path analysis. To estimate the mean of these ten traits, with a maximum error of 10% of the mean and 95% confidence level, 67 plants are needed. In an experiment, to estimate the mean of each treatment with 10% precision, 67 plants per treatment must be evaluated. The number of leaves has a positive linear relation with leaf fresh and dry matter. Number of leaves and stem diameter have a positive linear relation with stem and shoot fresh and dry matter.
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CHŁOPEK, Zdzisław. "The research of the probabilistic characteristics of exhaust emissions from vehicle engines". Combustion Engines 144, n. 1 (1 febbraio 2011): 49–55. http://dx.doi.org/10.19206/ce-117122.
Testo completoAbstract (sommario):
The influence of the probability density of the average speed on the probability density of the specific road exhaust emissions has been analyzed in the paper. The characteristics of the exhaust emissions from internal combustion engines warmed up to normal operating temperature have been examined. The research has been carried out for characteristics of the exhaust emissions from internal combustion engines of passenger vehicles. The research has been carried out for two kinds of functions in the form courses of average speed: of constant and normal distribution. The Monte Carlo Method has been used in the research. The probability density of the specific road exhaust emissions has been estimated. The zero–dimensional characteristics: the median, the kurtosis and the skewness coefficient, have been examined. A significant regularity of the displacement of the probability density towards smaller values in relation to the average speed probability density has been ascertained.
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Kaur, Amanpreet, e Sheojee Singh. "Emotional Intelligence of High School Students in Relation to their Spiritual Intelligence". Issues and Ideas in Education 10, n. 2 (22 settembre 2022): 83–90. http://dx.doi.org/10.15415/iie.2022.102009.
Testo completoAbstract (sommario):
Background: Emotional intelligence and spiritual intelligence are accompaniment to each other for refining human life. Spiritual intelligence builds up moral value, spiritual values and a strong belief system whereas emotional intelligence helps to develop personal relationships with one’s own self, social relationships with others and to manage the emotions. Purpose: The high school students are facing a major burst of emotions which needs to be channelized to give them the right direction in life. In this, their emotional intelligence and spiritual intelligence play an imperative role. Present research paper is an attempt to explore the relationship between emotional intelligence and spiritual intelligence of high school students. It examines how the spiritual intelligence affects the emotional intelligence of the students. Methods: This research is carried out on 150 students of 9th standard CBSE affiliated schools. For data collection, Spiritual Intelligence Scales by Misra (2014) and Emotional Intelligence Test by Soni and Sharma (2009) were used. The SPSS software is used for the analysis of the data. Descriptive Statistic: Mean, Median, Mode, Standard Deviation, Skewness and Kurtosis are calculated to check the normal distribution of the data and inferential statistics: Pearson Correlation Coefficient and Regression Analysis are calculated to measure the relationship between the variables under study. Results: The results of the study reject the null hypothesis and reveal that spiritual intelligence has a significant positive correlation with the emotional intelligence of the students. Conclusions: The study shows that the students who are spiritually more intelligent have more stable emotions as compared to the other students.
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Maahn, Maximilian, e Ulrich Löhnert. "Potential of Higher-Order Moments and Slopes of the Radar Doppler Spectrum for Retrieving Microphysical and Kinematic Properties of Arctic Ice Clouds". Journal of Applied Meteorology and Climatology 56, n. 2 (febbraio 2017): 263–82. http://dx.doi.org/10.1175/jamc-d-16-0020.1.
Testo completoAbstract (sommario):
AbstractRetrievals of ice-cloud properties from cloud-radar observations are challenging because the retrieval methods are typically underdetermined. Here, the authors investigate whether additional information can be obtained from higher-order moments and the slopes of the radar Doppler spectrum such as skewness and kurtosis as well as the slopes of the Doppler peak. To estimate quantitatively the additional information content, a generalized Bayesian retrieval framework that is based on optimal estimation is developed. Real and synthetic cloud-radar observations of the Indirect and Semi-Direct Aerosol Campaign (ISDAC) dataset obtained around Barrow, Alaska, are used in this study. The state vector consists of the microphysical (particle-size distribution, mass–size relation, and cross section–area relation) and kinematic (vertical wind and turbulence) quantities required to forward model the moments and slopes of the radar Doppler spectrum. It is found that, for a single radar frequency, more information can be retrieved when including higher-order moments and slopes than when using only reflectivity and mean Doppler velocity but two radar frequencies. When using all moments and slopes with two or even three frequencies, the uncertainties of all state variables, including the mass–size relation, can be considerably reduced with respect to the prior knowledge.
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Majeed, U., I. Tariq, M. Wasib e M. K. Mustafa. "Surface study of RF magnetron sputtered silicon nitride thin films". Journal of Optoelectronic and Biomedical Materials 15, n. 2 (aprile 2023): 55–64. http://dx.doi.org/10.15251/jobm.2023.152.55.
Testo completoAbstract (sommario):
Silicon nitride thin films were deposited on the one-sided P-type polished boron-doped silicon wafer substrate via RF magnetron sputtering using stochimetric silicon nitride target at various target-to-substrate distances. Target to substrate spacing, a nonconventional parameter, was varied to optimize the surface roughness and grain size. This optimization provided a normal distribution of homogenous, densely packed silicon nitride thin film free of surface cracks.. Atomic Force Microscopy was employed to explore the accurate surface roughness parameters of Silicon nitride thin films. The surface roughness and grain analysis for all samples exhibited a direct relation to each other and have an inverse correlation with the target to substrate spacing. The surface morphology of Si3N4 was analyzed by the following parameters; average roughness, root-mean square roughness, maximum peak to valley height, ten-point average roughness, skewness, and kurtosis of the line. The surface roughness of silicon nitride films has notable significance in the manufacturing of bio-sensor based on silicon nitride waveguides.
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Pornprasertmanit, Sunthud, e Todd D. Little. "Determining directional dependency in causal associations". International Journal of Behavioral Development 36, n. 4 (luglio 2012): 313–22. http://dx.doi.org/10.1177/0165025412448944.
Testo completoAbstract (sommario):
Directional dependency is a method to determine the likely causal direction of effect between two variables. This article aims to critique and improve upon the use of directional dependency as a technique to infer causal associations. We comment on several issues raised by von Eye and DeShon (2012) , including: encouraging the use of the signs of skewness and excessive kurtosis of both variables, discouraging the use of D’Agostino’s K2, and encouraging the use of directional dependency to compare variables only within time points. We offer improved steps for determining directional dependency that fix the problems we note. Next, we discuss how to integrate directional dependency into longitudinal data analysis with two variables. We also examine the accuracy of directional dependency evaluations when several regression assumptions are violated. Directional dependency can suggest the direction of a relation if: (a) the regression error in population is normal; (b) an unobserved explanatory variable correlates with any variables equal to or less than .2; (c) a curvilinear relation between both variables is not strong (standardized regression coefficient ≤ .2); (d) there are no bivariate outliers; and (e) both variables are continuous.
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Wardaya, Didik, Lantip Diat Prasojo e Sugiyono Sugiyono. "Factors affecting students’ choice of educational administration major: Why do students join the program?" International Journal of Evaluation and Research in Education (IJERE) 10, n. 4 (1 dicembre 2021): 1125. http://dx.doi.org/10.11591/ijere.v10i4.21904.
Testo completoAbstract (sommario):
<p>The study examined factors affecting Behavioral Intention (BI) regarding students’ choice of educational administration as their major. Samples were taken from Indonesian students. The process was begun with the adaptation of survey instruments from previous studies validated through content validity. In testing the normality, Skewness and Kurtosis values were computed. Reliability assessment was applied through Cronbach’s alpha. Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) were both conducted for the constructs. In examining the relationship, Structural Equation Modeling (SEM) analysis using AMOS 23.0 was applied to 257 responses. The findings informed that two relationships were significant while the other two are insignificant. Perceived Behavioral Control (PBC) and Attitude (AT) significantly predicted BI, while Subjective Norm (SN) and Facilitating Condition (FC) did not significantly predict BI. The current study can expand an in-depth contribution and reference for further researchers as a basis of the empirical evidence in relation to the validated survey questionnaire. Access to the questionnaire may contribute to educational stakeholders establishing policies to improve students’ interests in studying in an educational administration study program.</p>
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W. Ren, L., M. S. Abd Rahman e A. Mohd Ariffin. "Classification of Partial Discharge Sources using Statistical Approach". Indonesian Journal of Electrical Engineering and Computer Science 6, n. 3 (1 giugno 2017): 537. http://dx.doi.org/10.11591/ijeecs.v6.i3.pp537-543.
Testo completoAbstract (sommario):
<p>In high-voltage (HV) power equipment, degradation of insulation has been main concern for protection of equipment. This is due to occurrence of partial discharges (PD) activity within HV insulating systems which can be initiated from different types of local internal or external defects. Thus, partial discharge (PD) identification and classification are important for diagnostic insulation systems problems in order to ensure maintenance process can be carried out effectively and hence improve reliability and durable operation of HV equipment. In this work, the relation of the observable statistical characteristics from PD data with the characteristic of the defect is an important factor to determine the defect inside insulation system. Ultimately, the statistical parameters obtained from PD data can be used to classify different PD sources occur inside HV insulation system. Thus, the objective of this paper is to produce a unique pattern according to discharge source using statistical method. Several statistical parameters such as mean, variance, standard deviation, skewness and kurtosis have been used and analysed.</p>
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Ramanaiah, M., M. Balakrishna, S. Gouthamsri, Lakshmi M. Sowbhagya e K. Jayarao. "Impact of Sodium Dodecyl Sulfate Anionic Micelles on the Complex Equilibria of Divalent Metal Ions with 5-Sulfosalicylic Acid". Research Journal of Chemistry and Environment 28, n. 3 (31 gennaio 2024): 10–18. http://dx.doi.org/10.25303/283rjce010018.
Testo completoAbstract (sommario):
The potentiometric measurement was conducted to determine the formation of metal-ligand complex species between 5-sulfosalicylic acid and divalent calcium, magnesium and zinc metal ions. The experiment involved varying concentrations of sodium dodecyl sulphate (0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 percent w/v). The experimental procedure was conducted at a temperature of 303 Kelvin, utilizing sodium chloride (NaCl) to regulate the ionic strength to a value of 0.16 moles per cubic decimeter. The dynamic species of 5-sulfosalicylic acid are LH2- and LH2-. The selection of the best fit for the complex speciation was based on statistical criteria including skewness, χ2, kurtosis and crystallographic R-factor. The formation of the complexes ML2H, ML2H2 and ML3H3 was seen upon as the complexation of metal ions with 5-sulfosalicylic acid. The relationship between electrostatics and the stability of complex species has been demonstrated. Additionally, the dispersion of chemical species in relation to pH and compositional variety has been observed. This study investigates the potential existence of intricate equilibria.
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Torres-Ortega, Rosina, Héctor Guillén-Alonso, Raúl Alcalde-Vázquez, Enrique Ramírez-Chávez, Jorge Molina-Torres e Robert Winkler. "In Vivo Low-Temperature Plasma Ionization Mass Spectrometry (LTP-MS) Reveals Regulation of 6-Pentyl-2H-Pyran-2-One (6-PP) as a Physiological Variable during Plant-Fungal Interaction". Metabolites 12, n. 12 (8 dicembre 2022): 1231. http://dx.doi.org/10.3390/metabo12121231.
Testo completoAbstract (sommario):
Volatile organic compounds (VOCs) comprises a broad class of small molecules (up to ~300 g/mol) produced by biological and non-biological sources. VOCs play a vital role in an organism’s metabolism during its growth, defense, and reproduction. The well-known 6-pentyl-α-pyrone (6-PP) molecule is an example of a major volatile biosynthesized by Trichoderma atroviride that modulates the expression of PIN auxin-transport proteins in primary roots of Arabidopsis thaliana during their relationship. Their beneficial relation includes lateral root formation, defense induction, and increased plant biomass production. The role of 6-PP has been widely studied due to its relevance in this cross-kingdom relationship. Conventional VOCs measurements are often destructive; samples require further preparation, and the time resolution is low (around hours). Some techniques enable at-line or real-time analyses but are highly selective to defined compounds. Due to these technical constraints, it is difficult to acquire relevant information about the dynamics of VOCs in biological systems. Low-temperature plasma (LTP) ionization allows the analysis of a wide range of VOCs by mass spectrometry (MS). In addition, LTP-MS requires no sample preparation, is solvent-free, and enables the detection of 6-PP faster than conventional analytical methods. Applying static statistical methods such as Principal Component Analysis (PCA) and Discriminant Factorial Analysis (DFA) leads to a loss of information since the biological systems are dynamic. Thus, we applied a time series analysis to find patterns in the signal changes. Our results indicate that the 6-PP signal is constitutively emitted by T. atroviride only; the signal shows high skewness and kurtosis. In A. thaliana grown alone, no signal corresponding to 6-PP is detected above the white noise level. However, during T. atroviride-A. thaliana interaction, the signal performance showed reduced skewness and kurtosis with high autocorrelation. These results suggest that 6-PP is a physiological variable that promotes homeostasis during the plant-fungal relationship. Although the molecular mechanism of this cross-kingdom control is still unknown, our study indicates that 6-PP has to be regulated by A. thaliana during their interaction.
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Patel, Arjun, Thomas C. Edwards, Gareth Jones, Alexander D. Liddle, Justin Cobb e Amy Garner. "Metabolic equivalent of task scores avoid the ceiling effect observed with conventional patient-reported outcome scores following knee arthroplasty". Bone & Joint Open 4, n. 3 (6 marzo 2023): 129–37. http://dx.doi.org/10.1302/2633-1462.43.bjo-2022-0119.r1.
Testo completoAbstract (sommario):
AimsThe metabolic equivalent of task (MET) score examines patient performance in relation to energy expenditure before and after knee arthroplasty. This study assesses its use in a knee arthroplasty population in comparison with the widely used Oxford Knee Score (OKS) and EuroQol five-dimension index (EQ-5D), which are reported to be limited by ceiling effects.MethodsA total of 116 patients with OKS, EQ-5D, and MET scores before, and at least six months following, unilateral primary knee arthroplasty were identified from a database. Procedures were performed by a single surgeon between 2014 and 2019 consecutively. Scores were analyzed for normality, skewness, kurtosis, and the presence of ceiling/floor effects. Concurrent validity between the MET score, OKS, and EQ-5D was assessed using Spearman’s rank.ResultsPostoperatively the OKS and EQ-5D demonstrated negative skews in distribution, with high kurtosis at six months and one year. The OKS demonstrated a ceiling effect at one year (15.7%) postoperatively. The EQ-5D demonstrated a ceiling effect at six months (30.2%) and one year (39.8%) postoperatively. The MET score did not demonstrate a skewed distribution or ceiling effect either at six months or one year postoperatively. Weak-moderate correlations were noted between the MET score and conventional scores at six months and one year postoperatively.ConclusionIn contrast to the OKS and EQ-5D, the MET score was normally distributed postoperatively with no ceiling effect. It is worth consideration as an arthroplasty outcome measure, particularly for patients with high expectations.Cite this article: Bone Jt Open 2023;4(3):129–137.
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Hossain, Md Sumon, Md Johir Rayhan, Maeen Uddin e S. M. Masudur Rahman. "Analyzing the Level of CSR Practices in Relation to Customer Satisfaction in the Context of Banking Industry in Bangladesh". International Journal of Economics and Financial Issues 13, n. 4 (7 luglio 2023): 92–101. http://dx.doi.org/10.32479/ijefi.14523.
Testo completoAbstract (sommario):
This study aims to show the degree of Corporate Social Responsibility (CSR) practices and satisfaction of customer that are related while determining the relationship (Significant or Insignificant) between these two in the context of banking industry in Bangladesh. Authors adopt simple random sampling and collects data from 335 customers of ten listed banking companies through a survey questionnaire. The data have been analyzed through employing various statistical tests such as Skewness, kurtosis, cook distance, variance inflation factor (VIF), Durbin-Watson statistics and simple regression analysis. According to the authors' analysis of the composite Index, the teacher's mean customer satisfaction (CS) index and mean CSR practice index are both at their highest levels. The relationship measured by composite index between CSR practice and customer satisfaction that is found strongly positive and significant, indicated by empirical findings. The finding implies that if CSR initiatives increase, customer satisfaction levels will rise as a result. The authors have deduced from the literature that there isn't any evidence of an investigation that looks at the relationship between CSR practices and customer satisfaction among Bangladeshi companies; hence, there is a contribution to new knowledge as the analysis produces new insights in the context of a developing economy.
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Maahn, Maximilian, Ulrich Löhnert, Pavlos Kollias, Robert C. Jackson e Greg M. McFarquhar. "Developing and Evaluating Ice Cloud Parameterizations for Forward Modeling of Radar Moments Using in situ Aircraft Observations". Journal of Atmospheric and Oceanic Technology 32, n. 5 (maggio 2015): 880–903. http://dx.doi.org/10.1175/jtech-d-14-00112.1.
Testo completoAbstract (sommario):
AbstractObserving ice clouds using zenith pointing millimeter cloud radars is challenging because the transfer functions relating the observables to meteorological quantities are not uniquely defined. Here, the authors use a spectral radar simulator to develop a consistent dataset containing particle mass, area, and size distribution as functions of size. This is an essential prerequisite for radar sensitivity studies and retrieval development. The data are obtained from aircraft in situ and ground-based radar observations during the Indirect and Semi-Direct Aerosol Campaign (ISDAC) campaign in Alaska. The two main results of this study are as follows: 1) An improved method to estimate the particle mass–size relation as a function of temperature is developed and successfully evaluated by combining aircraft in situ and radar observations. The method relies on a functional relation between reflectivity and Doppler velocity. 2) The impact on the Doppler spectrum by replacing measurements of particle area and size distribution by recent analytical expressions is investigated. For this, higher-order moments such as skewness and kurtosis as well as the slopes of the Doppler spectrum are also used as a proxy for the Doppler spectrum. For the area–size relation, it is found that a power law is not sufficient to describe particle area and small deviations from a power law are essential for obtaining consistent higher moments. For particle size distributions, the normalization approach for the gamma distribution of Testud et al., adapted to maximum diameter as size descriptor, is preferred.
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Nicholson, Lindsey I., Michael McCarthy, Hamish D. Pritchard e Ian Willis. "Supraglacial debris thickness variability: impact on ablation and relation to terrain properties". Cryosphere 12, n. 12 (29 novembre 2018): 3719–34. http://dx.doi.org/10.5194/tc-12-3719-2018.
Testo completoAbstract (sommario):
Abstract. Shallow ground-penetrating radar (GPR) surveys are used to characterize the small-scale spatial variability of supraglacial debris thickness on a Himalayan glacier. Debris thickness varies widely over short spatial scales. Comparison across sites and glaciers suggests that the skewness and kurtosis of the debris thickness frequency distribution decrease with increasing mean debris thickness, and we hypothesize that this is related to the degree of gravitational reworking the debris cover has undergone and is therefore a proxy for the maturity of surface debris covers. In the cases tested here, using a single mean debris thickness value instead of accounting for the observed small-scale debris thickness variability underestimates modelled midsummer sub-debris ablation rates by 11 %–30 %. While no simple relationship is found between measured debris thickness and morphometric terrain parameters, analysis of the GPR data in conjunction with high-resolution terrain models provides some insight into the processes of debris gravitational reworking. Periodic sliding failure of the debris, rather than progressive mass diffusion, appears to be the main process redistributing supraglacial debris. The incidence of sliding is controlled by slope, aspect, upstream catchment area and debris thickness via their impacts on predisposition to slope failure and meltwater availability at the debris–ice interface. Slope stability modelling suggests that the percentage of the debris-covered glacier surface area subject to debris instability can be considerable at glacier scale, indicating that up to 32 % of the debris-covered area is susceptible to developing ablation hotspots associated with patches of thinner debris.
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Kaur, Amanpreet, e Dr Sheojee Singh. "Study of Emotional Intelligence of High School Students in Relation to the School Climate and its Dimensions". International Journal of All Research Education and Scientific Methods 12, n. 02 (2023): 989–96. http://dx.doi.org/10.56025/ijaresm.2023.120124996.
Testo completoAbstract (sommario):
Background: School climate has a notable impact on students’ emotional intelligence, as they spent a very crucial part of their life in schools. They begin the journey of their future from schools at the very early stage of their life. Purpose: This study aims to examine the relationship between emotional intelligence of high school students (N =150) in relation to the school climate. Method: This descriptive research was carried out on a sample of 150 students of 9thgradeof CBSE affiliated schools. For data collection School Climate Scale by Singh and Imam (2015) and Emotional Intelligence Test by Soni and Sharma (2009) were used. The normality of the data was checked using descriptive statistics (mean, median, mode, standard deviation, Skewness and Kurtosis) and inferential statistics (Pearson Correlation coefficient and Regression analysis) was used to measure relationship between the variables under study. Results: The findings of the studyreveals, school climate has significant positive correlation with emotional intelligence of the students which implies that the emotional intelligence of students and school climate are positivelyco-related. Conclusion: The study shows that students who study in positive school climate (which has reasonable freedom and result oriented environment)have more stable emotions as compared to the other students. Students feel motivated to learn and develop healthy emotions.Indeed, the quality of the school climate is the most predictive factor in any school’s capacity to promote student’s emotional intelligence.
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Mao, Wengang, e Igor Rychlik. "Estimation of Extreme Ship Response". Journal of Ship Research 56, n. 01 (1 marzo 2012): 23–34. http://dx.doi.org/10.5957/jsr.2012.56.1.23.
Testo completoAbstract (sommario):
In practice the severity of ship response is measured by high quantiles of long-term distribution of the response. The distribution is estimated by combining the short-term distribution of the response with a long-term probability distribution of encountered sea states. The paper describes an alternative approach, the so-called Rice's method, based on estimation of expected number of upcrossings of high levels by stress during 1 year. The method requires description of long-term variability of the standard deviation, skewness, kurtosis, and zero upcrossing frequency of ship response. It is assumed that the parameters are functions of encountered significant wave height, heading angle, and ship speed. The relation can be estimated from the measured stresses or computed by dedicated software assuming rigid ship hull model. Then Winterstein's transformed Gaussian model is used to estimate the upcrossing rates of response during a sea state. The proposed method is validated using the full-scale measurements of a 2,800 TEU container ship during the first 6 months of 2008. Numerical estimation of 4,400 TEU container ship extreme of the extreme response for a 4400 TEU container ship illustrates the approach when no measurements are available.
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Rao, Dasari Kondala, e Kolla Srinivas. "Comparision of Dominant Features Identification for Tool Wear in Hard Turning of Inconel 718 by Using Vibration Analysis". Strojnícky časopis - Journal of Mechanical Engineering 69, n. 4 (1 dicembre 2019): 1–8. http://dx.doi.org/10.2478/scjme-2019-0038.
Testo completoAbstract (sommario):
AbstractIn various machining processes, the vibration signals are studied for tool condition monitoring often referred as wear monitoring. It is essential to overcome unpredicted machining trouble and to improvise the efficiency of the machine. Tool wear is a vital problem in materials such as nickel based alloys as they have high hardness ranges. Though they have high hardness, a nickel based alloy Inconel 718 with varying HRC (51, 53, and 55), is opted as work material for hard turning process in this work. Uncoated carbide, coated carbide and ceramic tools are employed as cutting tools. Taguchi’s L9 orthogonal array is considered by taking hardness, speed, feed and depth of cut as four input parameters, the number of experiments and the combinations of parameters for every run is obtained. The vibration signals are recorded at various stages of cutting, till the tool failure is observed. Taking this vibration signal data as input to ANOVA and Grey relation analysis (GRA) which categorizes the optimal and utmost dominant features such as Root Mean Square (RMS), Crest Factor (CF), Skewness (Sk), Kurtosis (Ku), Absolute Deviation (AD), Mean, Standard Deviation (SD), Variance, peak, Frequency and Time in the tool wear process.
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Kjesbu, O. S., P. R. Witthames, P. Solemdal e M. Greer WalKer. "Ovulatory Rhythm and a Method to Determine the Stage of Spawning in Atlantic Cod (Gadus morhua)". Canadian Journal of Fisheries and Aquatic Sciences 47, n. 6 (1 giugno 1990): 1185–93. http://dx.doi.org/10.1139/f90-138.
Testo completoAbstract (sommario):
The size frequency distribution of the vitellogenic oocytes in Atlantic cod (Gadus morhua) changes in a predictable manner as spawning progresses. This change was studied by sampling successive batches of eggs from reared cod kept in the laboratory. The shape of the vitellogenic oocyte mode was described by measuring the diameter, standard deviation, and skewness and kurtosis. Linear regressions were derived which related the portion of the total number of eggs spawned per season (PES) to the number of vitellogenic oocytes per gram of the ovary and in relation to the standard deviation of the distribution. This method which allows the PES in a spawning fish to be estimated has the following applications. For fish stock assessment purposes fecundity estimates can be made on spawning rather than prespawning fish and residence times on spawning grounds can be calculated. In addition successive batches of eggs can be identified and studied. This is important in hormonal and larval studies. A detailed description is given of the oocyte growth during the ovulatory rhythm. The rhythm consists of four periods: arrest, final growth, hydration, and ovulation. It is suggested that the egg size is determined during the final growth period.
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Okunlola, Abiodun F., Olajumoke R. Ogunniyi, Rafiu Adewale Aregbeshola e Michael A. Alatise. "External Financing of Budget on Sustainable Economic Growth in Nigeria". International Journal of Financial Research 14, n. 3 (17 maggio 2023): 43. http://dx.doi.org/10.5430/ijfr.v14n3p43.
Testo completoAbstract (sommario):
The papers attempt to validate/invalidate economic growth sustainability vis-à-vis external financing of budget in Nigeria. The external financing channels - multilateral, Paris Club, London Club, promissory notes, bilateral, Euro bond, diaspora debts, and others - were tracked in relation to economic growth sustainability. The data is accessed from Emission Database for Global Atmospheric Research [EDGAR], the World Bank Development Indicator (WDI), and the Central Bank of Nigeria (CBN) statistical bulletin, for forty years (1981 to 2020). The study analysis follows plotting the visual trend of the series to ascertain its movement over time. Likewise, descriptive inference – skewness (sk), Kurtosis (k) & Jacque-Bera (JB) statistics were inferred for series normality. Also, Augmented Dickey-Fuller (ADF) unit root test, cointegration, vector autoregression (VAR), and the impulse response function (IRF) technique formed the basis of the estimation tools. Finding validates that there is no significant long-run relationship between external financing of the budget and sustainable economic growth in Nigeria. As a result, a reduction, and or a stop to further contracting external financing for budget purposes, and ensuring a funding-project-tied, is strongly recommended.
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Trzepieciński, Tomasz, Marcin Szpunar, Andrzej Dzierwa e Krzysztof Żaba. "Investigation of Surface Roughness in Incremental Sheet Forming of Conical Drawpieces from Pure Titanium Sheets". Materials 15, n. 12 (16 giugno 2022): 4278. http://dx.doi.org/10.3390/ma15124278.
Testo completoAbstract (sommario):
The article presents the results of the analysis of the influence of incremental sheet forming process parameters on surface roughness measured on both sides of conical drawpieces made from pure titanium Grade 2 sheets. The experimental plan was created on the basis of a central composite design. The study assumed the variability of feed rate, spindle speed, and incremental step size in the following range: 500–2000 mm/min, 0–600 rpm, and 0.1–0.5 mm, respectively. Two strategies differing in the direction of the tool rotation in relation to the feed direction were also analysed. Analysis of variance is performed to understand the adequacy of the proposed model and the influence of the input parameters on the specific roughness parameter. The sensitivity of the process parameter on the selected surface roughness parameters was assessed using artificial neural networks. It was found that the change in the surface roughness of the inner surface of the drawpiece is not related to the change of surface roughness of the outer side. The morphology of the outer surface of the draw pieces was uniform with a much greater profile height than the inner surface that had interacted with the tool. Taking into account the outer surface of the drawpiece, the direction of tool rotation is also most closely correlated with the parameters Sa, Sz, and Sku. Step size and feed rate provide the highest information capacity in relation to skewness and kurtosis of the inner surface of the drawpiece.
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Huang, Qiandi, e Patchanok Kitikanan. "Production of the English “sh” by L2 Thai Learners: An Acoustic Study". Theory and Practice in Language Studies 12, n. 8 (1 agosto 2022): 1508–15. http://dx.doi.org/10.17507/tpls.1208.06.
Testo completoAbstract (sommario):
L2 sound production might vary in accordance with factors such as the vowel context and L2 experience held. This study investigates the production of the English “sh” by L2 Thai learners via acoustic analysis. The target sounds in this study were those in the initial position in three vowel contexts: high, low and back. The data were drawn from 48 subjects who were Thai undergraduate students. This sample was divided between two groups: high-experienced and low-experienced. All read the stimuli with the target sound in a carrier phrase. From this, their production was acoustically analysed with six acoustic measurements; duration, peak location, centroid, SD, skewness and kurtosis. The findings show that the English /ʃ/ produced by the high-experienced group was different from the English [ʃ] produced by the low-experienced group in many acoustic measurements. Furthermore, the English [ʃ] produced by the low-experienced group was found not to be different from the Thai [tɕʰ] in many acoustic aspects. These findings suggest that L2 experience supports L2 speech production. They also showed the effect of vowel context in relation to peak location and duration, as suggests the consideration of vowel context in the teaching of the L2 speech sounds.
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Okon Jacob, Augustine. "THE GROWTH OF NIGERIA'S ECONOMY FROM 1981 TO 2019 IN RELATION TO THE FINANCING OF AGRICULTURE". Food and Agri Economics Review 3, n. 2 (2023): 44–49. http://dx.doi.org/10.26480/faer.02.2023.44.49.
Testo completoAbstract (sommario):
The analysis of various economic variables in Nigeria from 1981 to 2019 shows that the country’s economy has been heavily reliant on oil exports, which has left it vulnerable to external shocks and hindered economic growth. This over-reliance on oil exports has led to neglect of the agricultural sector, which was once the main source of foreign currency earnings for Nigeria. As a result, there has been a decline in food production and an increase in imports. However, a study investigating the impact of government spending on agriculture on Nigeria’s economic growth using secondary data covering the same period shows that investing in agriculture is essential for Nigeria to achieve a diversified economy and sustainable economic growth. The study uses the Ordinary Least Square (OLS) approach and the Augmented Dickey-Fuller (ADF) unit root test to analyze the data and concludes that diversifying the economy into non-oil industries, such as agriculture, is likely to have a significant impact on economic growth. The regression analysis showed that government agricultural spending has a positive impact on economic growth. The findings suggest that RGDP, AO, AL, AE, and IFR had an up-down tendency, while INT had an up-down-up trend. The skewness statistic indicates that the variables’ frequency distributions were positively skewed, while the Kurtosis statistic indicates that they were normally distributed. The unit root tests indicate that all variables were stationary at 5%. The regression analysis showed that AO had a positive association with RGDP, while AL had a negative association with it. The study also provides additional information, such as the contribution of agriculture to Nigeria’s GDP and the statistical reliability of the variables.
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Okon Jacob, Augustine. "THE GROWTH OF NIGERIA'S ECONOMY FROM 1981 TO 2019 IN RELATION TO THE FINANCING OF AGRICULTURE". Food and Agri Economics Review 3, n. 2 (2023): 32–37. http://dx.doi.org/10.26480/faer.02.2023.32.37.
Testo completoAbstract (sommario):
The analysis of various economic variables in Nigeria from 1981 to 2019 shows that the country’s economy has been heavily reliant on oil exports, which has left it vulnerable to external shocks and hindered economic growth. This over-reliance on oil exports has led to neglect of the agricultural sector, which was once the main source of foreign currency earnings for Nigeria. As a result, there has been a decline in food production and an increase in imports. However, a study investigating the impact of government spending on agriculture on Nigeria’s economic growth using secondary data covering the same period shows that investing in agriculture is essential for Nigeria to achieve a diversified economy and sustainable economic growth. The study uses the Ordinary Least Square (OLS) approach and the Augmented Dickey-Fuller (ADF) unit root test to analyze the data and concludes that diversifying the economy into non-oil industries, such as agriculture, is likely to have a significant impact on economic growth. The regression analysis showed that government agricultural spending has a positive impact on economic growth. The findings suggest that RGDP, AO, AL, AE, and IFR had an up-down tendency, while INT had an up-down-up trend. The skewness statistic indicates that the variables’ frequency distributions were positively skewed, while the Kurtosis statistic indicates that they were normally distributed. The unit root tests indicate that all variables were stationary at 5%. The regression analysis showed that AO had a positive association with RGDP, while AL had a negative association with it. The study also provides additional information, such as the contribution of agriculture to Nigeria’s GDP and the statistical reliability of the variables.
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Jacob, Augustine Okon. "THE GROWTH OF NIGERIA'S ECONOMY FROM 1981 TO 2019 IN RELATION TO THE FINANCING OF AGRICULTURE". Business and Economics in Developing Countries 1, n. 2 (10 maggio 2023): 64–70. http://dx.doi.org/10.26480/bedc.02.2023.64.70.
Testo completoAbstract (sommario):
The analysis of various economic variables in Nigeria from 1981 to 2019 shows that the country’s economy has been heavily reliant on oil exports, which has left it vulnerable to external shocks and hindered economic growth. This over-reliance on oil exports has led to neglect of the agricultural sector, which was once the main source of foreign currency earnings for Nigeria. As a result, there has been a decline in food production and an increase in imports. However, a study investigating the impact of government spending on agriculture on Nigeria’s economic growth using secondary data covering the same period shows that investing in agriculture is essential for Nigeria to achieve a diversified economy and sustainable economic growth. The study uses the Ordinary Least Square (OLS) approach and the Augmented Dickey-Fuller (ADF) unit root test to analyze the data and concludes that diversifying the economy into non-oil industries, such as agriculture, is likely to have a significant impact on economic growth. The regression analysis showed that government agricultural spending has a positive impact on economic growth. The findings suggest that RGDP, AO, AL, AE, and IFR had an up-down tendency, while INT had an up-down-up trend. The skewness statistic indicates that the variables’ frequency distributions were positively skewed, while the Kurtosis statistic indicates that they were normally distributed. The unit root tests indicate that all variables were stationary at 5%. The regression analysis showed that AO had a positive association with RGDP, while AL had a negative association with it. The study also provides additional information, such as the contribution of agriculture to Nigeria’s GDP and the statistical reliability of the variables.
49
Filho, Alberto Cargnelutti, Cleiton Antonio Wartha, Jéssica Andiara Kleinpaul, Ismael Mario Marcio Neu e Daniela Lixinski Silveira. "Sample Size to Estimate the Mean and Median of Traits in Canola". Journal of Agricultural Science 10, n. 11 (15 ottobre 2018): 123. http://dx.doi.org/10.5539/jas.v10n11p123.
Testo completoAbstract (sommario):
The aim of this study was to determine the sample size (i.e., number of plants) required to estimate the mean and median of canola (Brassica napus L.) traits of the Hyola 61, Hyola 76, and Hyola 433 hybrids with precision levels. At 124 days after sowing, 225 plants of each hybrid were randomly collected. In each plant, morphological (plant height) and productive traits (number of siliques, fresh matter of siliques, fresh matter of aerial part without siliques, fresh matter of aerial part, dry matter of siliques, dry matter of aerial part without siliques, and dry matter of aerial part) were measured. For each trait, measures of central tendency, variability, skewness, and kurtosis were calculated. Sample size was determined by resampling with replacement of 10,000 resamples. The sample size required for the estimation of measures of central tendency (mean and median) varies between traits and hybrids. Productive traits required larger sample sizes in relation to the morphological traits. Larger sample sizes are required for the hybrids Hyola 433, Hyola 61, and Hyola 76, in this sequence. In order to estimate the mean of canola traits of the Hyola 61, Hyola 76 e Hyola 433 hybrids with the amplitude of the confidence interval of 95% equal to 30% of the estimated mean, 208 plants are required. Whereas 661 plants are necessary to estimate the median with the same precision.
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Shakir Ali, Issam Mohammad, Nagham Shakir, Turkie e Abd Al-razackAbd Hussein Fares. "Combined CFA-AFM Analytical approach for precipitation reaction regarding crystal growth building single and multiple monolayers based on surface area calculation with image surface roughness analysis (unseen surface)". Journal of Physics: Conference Series 2063, n. 1 (1 novembre 2021): 012031. http://dx.doi.org/10.1088/1742-6596/2063/1/012031.
Testo completoAbstract (sommario):
Abstract A reaction of Mebeverine hydrochloride (0.03mM) in pure form with sodium nitroprusside (0.07mM) to form OFF White precipitate. A constant feed was used to collect an enough amount in weight for AFM study. Continuous flow injection analysis was conducted as it is the aim of this study to combine FIA with AFM. To elucidate the study of surface morphology. Various parameters of AFM image surface roughness analysis were discussed in relation to the kind of precipitate formed. Skewness, kurtosis, peak-peak, ten peak height, fractal dimension, wavelength, core roughness depth, and reduced valley depth. All these with the four parameter mainly amplitude, hybrid, functional and spetial. Since no previous study of such was conducted; all usual mode of imaging was dealt with i.e., contact, non-contact and intermittent contact was defined. A non contact mode was used in this study. A detailed study of how the crystal growth buildup first mono layer (hypothetical based on the date obtained also how much each grain carry a concentration with the number that are on the first mono layer. Number of given samples of surface area calculation plus a demonstration of the hypothetically formed multi mono layers specially at high reactant concentration. The main aim of this project was the binding of AFM with FIA which is regarded as an new approach which might be a very useful knowledge for other researcher.