variable distribution
Recently Published Documents


TOTAL DOCUMENTS

113
(FIVE YEARS 28)

H-INDEX

18
(FIVE YEARS 1)

2021 ◽  
Author(s):  
Eleanor Landwehr ◽  
Meghan Baker ◽  
Takuya Oguma ◽  
Hannah Burdge ◽  
Takahiro Kawajiri ◽  
...  

Class III neuroactive metabolites from the bark of Galbu-limima belgraveana occur in variable distribution and are not easily procured by chemical synthesis. Here we decrease the synthetic burden of himgaline to nearly one-third of the prior best (7–9 vs. 19–31 steps) by cross-coupling high fraction aromatic (FAr) building blocks followed by com-plete, stereoselective reduction to high-fraction sp3 (Fsp3) products. This short entry into GB alkaloid space allows its extensive exploration and biological interrogation.


2021 ◽  
Author(s):  
Abdo Abou Jaoude

The mathematical probability concept was set forth by Andrey Nikolaevich Kolmogorov in 1933 by laying down a five-axioms system. This scheme can be improved to embody the set of imaginary numbers after adding three new axioms. Accordingly, any stochastic phenomenon can be performed in the set C of complex probabilities which is the summation of the set R of real probabilities and the set M of imaginary probabilities. Our objective now is to encompass complementary imaginary dimensions to the stochastic phenomenon taking place in the “real” laboratory in R and as a consequence to gauge in the sets R, M, and C all the corresponding probabilities. Hence, the probability in the entire set C = R + M is incessantly equal to one independently of all the probabilities of the input stochastic variable distribution in R, and subsequently the output of the random phenomenon in R can be evaluated totally in C. This is due to the fact that the probability in C is calculated after the elimination and subtraction of the chaotic factor from the degree of our knowledge of the nondeterministic phenomenon. We will apply this novel paradigm to the classical Bayes’ theorem in probability theory.


2021 ◽  
pp. 1-15
Author(s):  
Thomas M. Cullen ◽  
Lindsay Zanno ◽  
Derek W. Larson ◽  
Erinn Todd ◽  
Philip J. Currie ◽  
...  

The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skeletons. Although small theropods are well documented in the assemblage, taxonomic assessments are frequently based on isolated, fragmentary skeletal elements. Here we reassess DPF theropod biodiversity using morphological comparisons, high-resolution biostratigraphy, and morphometric analyses, with a focus on specimens/taxa originally described from isolated material. In addition to clarifying taxic diversity, we test whether DPF theropods preserve faunal zonation/turnover patterns similar to those previously documented for megaherbivores. Frontal bones referred to a therizinosaur (cf. Erlikosaurus), representing among the only skeletal record of the group from the Campanian–Maastrichtian (83–66 Ma) fossil record of North America, plot most closely to troodontids in morphospace, distinct from non-DPF therizinosaurs, a placement supported by a suite of troodontid anatomical frontal characters. Postcranial material referred to cf. Erlikosaurus in North America is also reviewed and found most similar in morphology to caenagnathids, rather than therizinosaurs. Among troodontids, we document considerable morphospace and biostratigraphic overlap between Stenonychosaurus and the recently described Latenivenatrix, as well as a variable distribution of putatively autapomorphic characters, calling the validity of the latter taxon into question. Biostratigraphically, there are no broad-scale patterns of faunal zonation similar to those previously documented in ornithischians from the DPF, with many theropods ranging throughout much of the formation and overlapping extensively, possibly reflecting a lack of sensitivity to environmental changes, or other cryptic ecological or evolutionary factors.


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 504
Author(s):  
Danuta Smołka-Danielowska ◽  
Agata Walencik-Łata

The paper presents the results of research on rare earth elements (REY) and selected radionuclides in barren rocks deposited on a heap at a mine belonging to the Polish Mining Group (the largest producer of hard coal in EU countries). The maximum concentration of REEs determined in silstones was 261.6 mg/kg and in sandstones 221.2 mg/kg. The average uranium and thorium content in silstones was 6.8 mg/kg and 11.6 mg/kg, respectively. On the other hand, the samples of burnt coal shales contain on average 3.5 mg/kg of uranium and 9.7 mg/kg of thorium. In all coal waste samples, the REE values are higher than in hard coal (15.7 mg/kg). Carriers of REY, uranium, and thorium in coal waste are detritic minerals: monazite and xenotime, which are part of the grain skeleton of barren rocks. Coal waste samples are characterized by a variable distribution of REY concentrations as well as a variable content of radionuclides. The 226Ra, 228Ra, and 40K measurements in the investigated samples were performed using the gamma spectrometry technique. The concentrations of the analyzed isotopes differed depending on the mineralogical composition of the investigated samples. The present study results may be important in determining the possibility of utilization of wastes of barren rocks stored in the mine heap and in assessing environmental and radiological hazards.


Radiotekhnika ◽  
2021 ◽  
pp. 128-134
Author(s):  
I. Moshchenko ◽  
O. Nikitenko ◽  
Yu.V. Kozlov

The use of CMS Maple for students' practical and independent work is described. The study of random variable distribution laws is actual. Statistical calculations without computer are difficult and require many functional and quintiles tables of standard distributions. This does not contribute to feeling the element of novelty in the material being studied, to be able to arbitrarily change the conditions of tasks, etc., it takes a lot of time in solving applied production problems, which is inappropriate Thus to determine and research random variable distribution laws both in practical applications and in studying we must use special mathematical packages. The most extended of them are Mathcad, MatLab, Mathematica, Maple. Specialized statistical packages (SAS, SPSS, STATISTIKA, STATGRAPHICS) are not relevant to study. Their use for studying requires very high education level in mathematical statistics. Most of the existing math packages allow users to operate at random variables, including the Computer Mathematics System (CMS) Maple. Thus, the purpose of this article is a description of the studying possibilities of the random variables distribution laws with CMS Maple and the application of the acquired skills to the independent work of students. The Maple Statistics Library has a large set of commands for analyzing data, computing various numerical characteristics of random variables, graphing their distribution laws, and for statistical data processing. Thanks to a powerful set of statistical tools, the possibility of symbolic calculations and data processing of CMS Maple, wide possibilities of graphical interpretation of the results obtained not only in a static but also in a dynamic form, it is advisable to use it when studying the topic "Distribution Laws of Random Variables" in students' practical and independent work to use their acquired skills in solving applied problems of science and technology.


2021 ◽  
Vol 31 (2) ◽  
Author(s):  
Menbeu Sultan ◽  
Desalegn Kene ◽  
Woldesenbet Waganew ◽  
Aschalew Worku ◽  
Aklilu Azazh ◽  
...  

BACKGROUND: Since the occurrence of COVID-19 in the world, it has claimed nearly 1.39 million human lives in the world and more than 1500 lives in Ethiopia. The number of deaths is increasing with variable distribution in the world. Despite its increasing fatality, the clinical characteristics of the deceased patients are not yet fully known. Analyzing the clinical characteristics of deceased patients will help to improve the outcome of infected patients. Hence, this study aimed to determine the clinical characteristics of patients who died due to COVID-19 in Ethiopia.METHODS: Hospital based multi-center cross-sectional study was conducted using chart review of deceased patients. Since the number of COVID-19 related deaths was limited, all consecutive COVID-19 related hospital deaths were analyzed. The data was entered into and analyzed using SPSS version 25.0. Descriptive statistics was used to explain the data collected from the survey.RESULT: A total of 92 deceased patient charts were analyzed. Of these patients, 65(71%) were males. Age ranged from 17 to 92 years (mean age being 59 years). On arrival vital signs, 60.5% of them had hypoxia, 49% had tachycardia and only 32% of patients had fever. Three fourth of the patients 64/85 had at least one comorbidity. Diabetes mellitus (DM) was the commonest comorbidity accounting for 445.9%, followed by hypertension, 23/85(27%), and HIV/ AIDS, 15/85 (17.5%).CONCLUSION: The results of this study showed that COVID-19 deceased patients presented with respiratory failure and hypoxia. However, less than a third of these patients had fever. In addition, the presence of comorbid illnesses and non-COVID-19 diseases like AIDS defining illness in significant amount needs further study to identify their level of contribution to the increasing burden of COVID-19 deaths in Ethiopia.


Author(s):  
S. A. Fastov ◽  
I. V. Zorin ◽  
V. I. Lysak ◽  
D. A. Murugov

The results of the experimental studies hardfacing of the 55NiCrMoV5 die steel of the three types of wear and heat-resistant alloys with preheating are presented. The effect of the preheating on the structure hardfaced alloys as well as on the heat affected zone formation of the base metal is estimated. It is revealed that the use of preheating under the considered conditions of surfacing causes the formation of a structural heterogeneity of the heat-affected zone of the base metal, which manifests itself as a variable distribution of chromium and molybdenum.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Carmen Patino-Rodriguez ◽  
Diana M. Pérez ◽  
Olga Usuga Manco

PurposeThe purpose of this paper is to evaluate the performance of a modified EWMA control chart (γEWMA control chart), which considers data distribution and incorporate its correlation structure, simulating in-control and out-of-control processes and to select an adequate value for smoothing parameter with these conditions.Design/methodology/approachThis paper is based on a simulation approach using the methodology for evaluating statistical methods proposed by Morris et al. (2019). Data were generated from a simulation considering two factors that associated with data: (1) quality variable distribution skewness as an indicator of quality variable distribution; (2) the autocorrelation structure for type of relationship between the observations and modeled by AR(1). In addition, one factor associated with the process was considered, (1) the shift in the process mean. In the following step, when the chart control is modeled, the fourth factor intervenes. This factor is a smoothing parameter. Finally, three indicators defined from the Run Length are used to evaluate γEWMA control chart performance this factors and their interactions.FindingsInteraction analysis for four factor evidence that the modeling and selection of parameters is different for out-of-control and in-control processes therefore the considerations and parameters selected for each case must be carefully analyzed. For out-of-control processes, it is better to preserve the original features of the distribution (mean and variance) for the calculation of the control limits. It makes sense that highly autocorrelated observations require smaller smoothing parameter since the correlation structure enables the preservation of relevant information in past data.Originality/valueThe γEWMA control chart there has advantages because it gathers, in single chart control: the process and modelling characteristics, and data structure process. Although there are other proposals for modified EWMA, none of them simultaneously analyze the four factors nor their interactions. The proposed γEWMA allows setting the appropriate smoothing parameter when these three factors are considered.


2021 ◽  
Vol 45 (3) ◽  
pp. 159-177
Author(s):  
Chen-Wei Liu

Missing not at random (MNAR) modeling for non-ignorable missing responses usually assumes that the latent variable distribution is a bivariate normal distribution. Such an assumption is rarely verified and often employed as a standard in practice. Recent studies for “complete” item responses (i.e., no missing data) have shown that ignoring the nonnormal distribution of a unidimensional latent variable, especially skewed or bimodal, can yield biased estimates and misleading conclusion. However, dealing with the bivariate nonnormal latent variable distribution with present MNAR data has not been looked into. This article proposes to extend unidimensional empirical histogram and Davidian curve methods to simultaneously deal with nonnormal latent variable distribution and MNAR data. A simulation study is carried out to demonstrate the consequence of ignoring bivariate nonnormal distribution on parameter estimates, followed by an empirical analysis of “don’t know” item responses. The results presented in this article show that examining the assumption of bivariate nonnormal latent variable distribution should be considered as a routine for MNAR data to minimize the impact of nonnormality on parameter estimates.


Sign in / Sign up

Export Citation Format

Share Document