68 research outputs found
Wavefield focusing using a generalised, potentially asymmetric homogeneous Green's function
No full textMarchenko-type integrals typically relate so-called focusing functions and Green's functions via the reflection response measured on the open surface of a volume of interest. Originating from one dimensional inverse scattering theory, the extension to two and three dimensions set in motion various new developments regarding imaging in complex materials. This extension, however, is based on wavefield decomposition inside the volume and a truncated medium state, i.e. a version of the medium that is reflection-free underneath the focusing location, suggesting that evanescent, refracted and diving waves cannot be included in the representation. We elaborate on a new derivation for Marchenko-like integrals that (i) extends the concept of wavefield focusing by using a generalised homogeneous Green's function, (ii) is based on partial differential equations and thereby allows for additional insights and a new physical intuition for Marchenko equations, (iii) unifies wavefield focusing for open and closed boundary systems, (iv) does not require wavefield decomposition or a truncated medium state, thus including the full wavefield Green's function, (v) enables using forward modelling to obtain, e.g., Marchenko-type, time-compact focusing functions. We place a particular focus on the latter point, illustrating and investigating how to solve the underlying partial differential equations for various types of focusing functions. This paves the way for a deeper understanding of focusing functions as well as advanced full wavefield Marchenko schemes. While the derivations are generally presented for the 3D case, we show numerical examples in 1D.Applied Geophysics and Petrophysic
V Круглий стіл з міжнародною участю «Сучасні тенденції фонетичних досліджень»
No full textThe paper presents a view on rhythm and tempo as central elements of both speech and
music and their ability to convey emotions and influence them as well. The author dwells on
similarities of rhythm and tempo in speech and music while also mentioning the discrepancies
mainly caused by unpredictability of human speech and the necessity of accuracy in music
recordings. The importance of rhythm and tempo for textsetting is acknowledged
TOWARD THE SOURCES OF THE PROJECT OF “HISTORY OF RUSSIAN PHILOSOPHY” BY V. V. ZENKOVSKY
No full textThe article discusses a question of genesis of the fundamental “History of Russian Philosophy” by V.V. Zenkovsky. The author points out that one of the most meaningful factors (but not the only one) in that was the creating in 1910 of a group named “Put’” (“The Path”), devoted to the religious philosophy, and also creating of the interna-tional philosophy journal “Logos” — as well as the controversy about specific charac-ter and ways of development of Russian philosophy between V.F. Ern (“Put’ ”) from the one side, and B.V. Yakovenko, S.I. Gessen, F.A. Stepun (“Logos”) and S.L. Frank from the other. One can easily find signs of that controversy on the pages of famous work of Zenkovsky, though the main cause of appearance of this book was the Russian philoso-phy itself, an existence of which in all its peculiarity and significance became obvious in the middle of the XXth century
Multivariate Skew-t Distributions in Econometrics and Environmetrics
No full textThis dissertation is composed of three articles describing novel approaches for
analysis and modeling using multivariate skew-normal and skew-t distributions in
econometrics and environmetrics.
In the first article we introduce the Heckman selection-t model. Sample selection
arises often as a result of the partial observability of the outcome of interest in
a study. In the presence of sample selection, the observed data do not represent a
random sample from the population, even after controlling for explanatory variables.
Heckman introduced a sample-selection model to analyze such data and proposed a
full maximum likelihood estimation method under the assumption of normality. The
method was criticized in the literature because of its sensitivity to the normality assumption.
In practice, data, such as income or expenditure data, often violate the
normality assumption because of heavier tails. We first establish a new link between
sample-selection models and recently studied families of extended skew-elliptical distributions.
This then allows us to introduce a selection-t model, which models the
error distribution using a Student���s t distribution. We study its properties and investigate
the finite-sample performance of the maximum likelihood estimators for
this model. We compare the performance of the selection-t model to the Heckman
selection model and apply it to analyze ambulatory expenditures.
In the second article we introduce a family of multivariate log-skew-elliptical distributions,
extending the list of multivariate distributions with positive support. We
investigate their probabilistic properties such as stochastic representations, marginal
and conditional distributions, and existence of moments, as well as inferential properties.
We demonstrate, for example, that as for the log-t distribution, the positive
moments of the log-skew-t distribution do not exist. Our emphasis is on two special
cases, the log-skew-normal and log-skew-t distributions, which we use to analyze U.S.
precipitation data.
Many commonly used statistical methods assume that data are normally distributed.
This assumption is often violated in practice which prompted the development
of more flexible distributions. In the third article we describe two such multivariate
distributions, the skew-normal and the skew-t, and present commands for
fitting univariate and multivariate skew-normal and skew-t regressions in the statistical
software package Stata
Estimating variance components in Stata
No full textThis article gives a brief overview of the popular methods for estimating variance components in linear models and describes several ways to obtain such estimates in Stata for various experimental designs. The article’s emphasis is on using xtmixed to estimate variance components. Prior to Stata 9, loneway could be used to estimate variance components for one-way random-effects models. For other experimental designs, variance components could be computed manually using saved results after anova. The latter approach is viable but requires tedious computations for complicated experimental designs. Instead, as of Stata 9, variance components are easily obtained by using xtmixed
METHODOLOGICAL ASPECTS OF COMPUTED TOMOGRAPHY ODONTOMORPHOMETRY OF BOYS AND GIRLS WITH THE PHYSIOLOGICAL BITE
No full textGunas I. V., Dmitriev N. A., Marchenko A. V. Methodological aspects of computed tomography odontomorphometry of boys and girls with the physiological bite. Journal of Education, Health and Sport. 2015;5(11):345-355. ISSN 2391-8306. DOIhttp://dx.doi.org/10.5281/zenodo.34097
http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%2811%29%3A345-355
https://pbn.nauka.gov.pl/works/670995
Formerly Journal of Health Sciences. ISSN 1429-9623 / 2300-665X. Archives 2011–2014http://journal.rsw.edu.pl/index.php/JHS/issue/archive
Deklaracja.
Specyfika i zawartość merytoryczna czasopisma nie ulega zmianie.
Zgodnie z informacją MNiSW z dnia 2 czerwca 2014 r., że w roku 2014 nie będzie przeprowadzana ocena czasopism naukowych; czasopismo o zmienionym tytule otrzymuje tyle samo punktów co na wykazie czasopism naukowych z dnia 31 grudnia 2014 r.
The journal has had 5 points in Ministry of Science and Higher Education of Poland parametric evaluation. Part B item 1089. (31.12.2014).
© The Author (s) 2015;
This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland and Radom University in Radom, Poland
Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium,
provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License
(http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.
This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial
use, distribution and reproduction in any medium, provided the work is properly cited.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Received: 25.09.2015. Revised 25.10.2015. Accepted: 20.11.2015.
UDC 616.716.8-071-084:613.956: 617.52:62-408
METHODOLOGICAL ASPECTS OF COMPUTED TOMOGRAPHY ODONTOMORPHOMETRY OF BOYS AND GIRLS WITH THE PHYSIOLOGICAL BITE
I.V. Gunas, *N.A. Dmitriev, **A.V. Marchenko
International Academy of Integrative Anthropology, Vinnitsa;
*Vinnitsa National Medical University named after Pirogov, Vinnitsa;
**Ukrainian Medical Dental Academy, Poltava
Summary
The article presented data regarding the average mesiodistal, vestibulо-oral and vertical dimensions of the teeth of boys and girls fromUkraine, obtained using cone beam computed tomography. We have studied 101 tomograms, male (n = 44) and female (n = 57) between the ages from 18 to 25 years with orthognathic bite. For this investigation we used dental cone beam computer tomography - Veraviewepocs 3D, Morita. When comparing the performance of odontometric features of the similar teeth from right and left sides, no significant differences were found. Established population characteristics for mesiodistal, vestibulo-oral and vertical dimensions of the teeth for the boys and girls fromUkrainewith orthognathic bite. For most sizes of teeth (except mesiodistal size of the second lower premolar) showed significant differences (larger sizes in boys).
Key words: odontometry, computed tomography, the size of the teeth.
Резюме
МЕТОДОЛОГІЧНІ АСПЕКТИ КОМП'ЮТЕРНО-ТОМОГРАФІЧНОЇ ОДОНТОМОРФОМЕТРІЇ У ЮНАКІВ ТА ДІВЧАТ З ФІЗІОЛОГІЧНИМ ПРИКУСОМ. У статті представлені дані щодо середньостатистичних мезіодистальних, вестибуло-оральних та вертикальних розмірів зубів у юнаків та дівчат України отриманих за допомогою конусно-променевої комп'ютерної томографії. Були вивчені 101 томограма представників чоловічої (n = 44) і жіночого (n = 57) статі у віці від 18 до 25 років з ортогнатичним прикусом. Для проведення даного дослідження використовували дентальний конусно-променевий комп'ютерний томограф - Veraviewepocs 3D, Morita. При порівнянні коп’ютернотомографічних метричних характеристик однойменних зубів правої і лівої сторін, достовірних відмінностей виявлено не було. Встановлені популяційні особливості мезіодистальних, вестибуло-оральних і вертикальних розмірів зубів для юнаків та дівчат України з ортогнатичним прикусом. Для більшості розмірів зубів (за винятком мезіодистального розміру другого нижнього премоляра) встановлені достовірні відмінності (більш великі розміри у юнаків).
Ключові слова: одонтометрія, комп'ютерна томографія, розміри зубів.
Резюме
МЕТОДОЛОГИЧЕСКИЕ АСПЕКТЫ КОМПЬЮТЕРНО-ТОМОГРАФИЧЕСКОЙ ОДОНТОМОРФОМЕТРИИ У ЮНОШЕЙ И ДЕВУШЕК С ФИЗИОЛОГИЧЕСКИМ ПРИКУСОМ. В статье представлены данные относительно среднестатистических мезиодистальных, вестибуло-оральных и вертикальных размеров зубов у юношей и девушек Украины, полученных с помощью конусно-лучевой компьютерной томографии. Были изучены 101 томограмма представителей мужского (n=44) и женского (n=57) пола в возрасте от 18 до 25 лет с ортогнатическим прикусом. Для проведения данного исследования использовали дентальный конусно-лучевой компьютерный томограф – Veraviewepocs 3D, Morita. При сравнении копьютернотомографических метрических характеристик одноименных зубов правой и левой сторон, достоверных различий обнаружено не было. Установлены популяционные особенности мезиодистальных, вестибуло-оральных и вертикальных размеров зубов для юношей и девушек Украины с ортогнатическим прикусом. Для большинства размеров зубов (за исключением мезиодистального размера второго нижнего премоляра) установлены достоверные различия (большие размеры у юношей).
Ключевые слова: одонтометрия, компьютерная томография, размеры зубов
Основні чинники, що визначають екологічну поведінку молодших школярів
No full textThe author has researched the factors that influence the formation of environmental behavior in primary school children. Understanding the main determinants that shape children's environmental views and practices can help educators and parents create effective strategies for fostering environmentally responsible behavior.
Автор дослідив фактори, що впливають на формування екологічної поведінки у дітей початкової школи. Розуміння основних детермінант, які формують екологічні погляди та практики дітей, може допомогти вихователям та батькам створити ефективні стратегії для виховання екологічно відповідальної поведінки
СИСТЕМАТИЗАЦИЯ КОМПОНЕНТОВ КОМПЕТЕНЦИИ СУБЪЕКТОВ ОКАЗАНИЯ БЕСПЛАТНОЙ ЮРИДИЧЕСКОЙ ПОМОЩИ В УКРАИНЕ: АДМИНИСТРАТИВНО-ПРАВОВОЙ АСПЕКТ
No full textIn the article, the author defines the general subject of conducting subjects for the provision of free legal assistance, systematizes their rights and obligations (powers), as well as conducts a generalized analysis and identifies common competency blocks for entities providing free legal assistance. У статті визначено загальний предмет діяльності суб’єктів з надання безоплатної правової допомоги, систематизовано їх права та обов’язки (повноваження), а також проведено узагальнений аналіз та визначено спільні блоки компетенції суб’єктів, які надають безоплатну правову допомогу. В статье определен общий предмет деятельности субъектов по оказанию безвозмездной правовой помощи, систематизированы их права и обязанности (полномочия), а также проведен обобщенный анализ и определены общие блоки компетенции субъектов, оказывающих безвозмездную правовую помощь
Multivariate log-skew-elliptical distributions with applications to precipitation data
No full textWe introduce a family of multivariate log-skew-elliptical distributions, extending the list of multivariate distributions with positive support. We investigate their probabilistic properties such as stochastic representations, marginal and conditional distributions, and existence of moments, as well as inferential properties. We demonstrate, for example, that as for the log-t distribution, the positive moments of the log-skew-t distribution do not exist. Our emphasis is on two special cases, the log-skew-normal and log-skew-t distributions, which we use to analyze US national (univariate) and regional (multivariate) monthly precipitation data. © 2009 John Wiley & Sons, Ltd.Genton’s research was supported in part by NSF grants DMS-0504896, CMG ATM-0620624, and by AwardNo. KUS-C1-016-04, made by King Abdullah University of Science and Technology (KAUST). The authors thankReinaldo B. Arellano-Valle, Kenneth P. Bowman, and a referee for their helpful comments and suggestions. The mapof US climatic regions was made available by the National Oceanic and Atmospheric Administration/Departmentof Commerc
A Heckman Selection- t Model
No full textSample selection arises often in practice as a result of the partial observability of the outcome of interest in a study. In the presence of sample selection, the observed data do not represent a random sample from the population, even after controlling for explanatory variables. That is, data are missing not at random. Thus, standard analysis using only complete cases will lead to biased results. Heckman introduced a sample selection model to analyze such data and proposed a full maximum likelihood estimation method under the assumption of normality. The method was criticized in the literature because of its sensitivity to the normality assumption. In practice, data, such as income or expenditure data, often violate the normality assumption because of heavier tails. We first establish a new link between sample selection models and recently studied families of extended skew-elliptical distributions. Then, this allows us to introduce a selection-t (SLt) model, which models the error distribution using a Student's t distribution. We study its properties and investigate the finite-sample performance of the maximum likelihood estimators for this model. We compare the performance of the SLt model to the conventional Heckman selection-normal (SLN) model and apply it to analyze ambulatory expenditures. Unlike the SLNmodel, our analysis using the SLt model provides statistical evidence for the existence of sample selection bias in these data. We also investigate the performance of the test for sample selection bias based on the SLt model and compare it with the performances of several tests used with the SLN model. Our findings indicate that the latter tests can be misleading in the presence of heavy-tailed data. © 2012 American Statistical Association.The authors thank the editor, the associate editor, and two referees for a careful review of the manuscript and valuable suggestions. The authors also thank Adelchi Azzalini and Reinaldo B. Arellano-Valle for helpful comments on an earlier version of the article, and David Drukker for useful discussions about selection models. Genton's research was partially supported by the National Science Foundation (NSF) grant DMS-1007504 and by award number KUS-C1-016-04 made by King Abdullah University of Science and Technology (KAUST)
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