scholarly journals Connectivity Analysis for Multivariate Time Series: Correlation vs. Causality

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1570
Author(s):  
Angeliki Papana
Keyword(s):  
Multivariate Time Series ◽  
The Other ◽  
Causal Effects ◽  
Connectivity Analysis ◽  
Satisfactory Performance ◽  
First Case ◽  
Correlation Measures ◽  
Open Question ◽  
Temporal Dependencies

The study of the interdependence relationships of the variables of an examined system is of great importance and remains a challenging task. There are two distinct cases of interdependence. In the first case, the variables evolve in synchrony, connections are undirected and the connectivity is examined based on symmetric measures, such as correlation. In the second case, a variable drives another one and they are connected with a causal relationship. Therefore, directed connections entail the determination of the interrelationships based on causality measures. The main open question that arises is the following: can symmetric correlation measures or directional causality measures be applied to infer the connectivity network of an examined system? Using simulations, we demonstrate the performance of different connectivity measures in case of contemporaneous or/and temporal dependencies. Results suggest the sensitivity of correlation measures when temporal dependencies exist in the data. On the other hand, causality measures do not spuriously indicate causal effects when data present only contemporaneous dependencies. Finally, the necessity of introducing effective instantaneous causality measures is highlighted since they are able to handle both contemporaneous and causal effects at the same time. Results based on instantaneous causality measures are promising; however, further investigation is required in order to achieve an overall satisfactory performance.

scholarly journals Acute Hepatitis B in a patient previously positive for antibody to surface antigen (anti-HBs) determined by radioimmunoassay: case report and review of the literature

1985 ◽  
Vol 27 (5) ◽  
pp. 258-263
Author(s):  
Edna Strauss ◽  
Amadeo Sáez-Alquézar ◽  
Augusta Takeda ◽  
Luiz Caetano da Silva
Keyword(s):  
Case Report ◽  
Low Cost ◽  
The Other ◽  
Screening Tests ◽  
Review Of The Literature ◽  
Vaccine Protection ◽  
First Case ◽  
Acute Hepatitis B ◽  
To Receive

The determination of anti-HBs as a screening test before vaccination has been advisable in order to encounter immune individuals that don't need to receive vaccine protection. A case-report is presented and three other cases are reviewed from the literature. Anti-HBs was positive in these health-care personnels that developped typical acute B hepatitis. Different subtyping involving the d/y determinants were found in the first case, but false-positive anti-HBs even with high titres, determined by RIA, were found in the other cases. Concomitant determination of anti-HBc or absence of screening tests seem to be more reasonable policies until a low-cost and risk-free vaccine is produced.

scholarly journals V.—What is a Metamorphic Rock?

1911 ◽  
Vol 8 (8) ◽  
pp. 356-361
Author(s):  
E. H. L. Schwarz
Keyword(s):  
Metamorphic Rock ◽  
The Other ◽  
Boric Oxide ◽  
Other Hand ◽  
First Case ◽  
Ore Bodies ◽  
The Masses ◽  
Open Question

The latest book on metamorphism, Dr. V. Grubenmann's Kristallinen Schiefer, still leaves it an open question what a metamorphic rock is. Generally speaking there is no doubt about the matter; every geologist has a more or less precise idea of what he means by the term, but no one has yet been able to propound a definition which is perfectly satisfactory, and which will enable one to distinguish a metamorphic rock from all other kinds and at the same time convey an expression of the characteristic peculiarities inherent in such a rock. The need of a definition is very necessary. The want of it has led Dr. Grubenmann to include some rocks among the crystalline schists which one ordinarily would not refer to that class, and on the other hand there are some rocks frequently referred to that class which are not included. In the first case, the masses of emery form the twelfth group of Dr. Grubenmann's classification, yet the analysis of the Naxos emery, which reveals traces of boric oxide (1.15 per cent. in one case) would seem to place these lenses among the ore-bodies deposited by pneumatolitic action.

On the theory of the perturbations of the planets

1837 ◽  
Vol 3 ◽  
pp. 98-98
Keyword(s):  
Differential Equation ◽  
Differential Equations ◽  
The Other ◽  
The Sun ◽  
Constant Force ◽  
First Case ◽  
Complete Determination ◽  
Analytical Formulae ◽  
Sole Action

The methods hitherto employed by mathematicians for determining the variations which the elements of the orbit of a planet undergo in consequence of perturbation, and for expressing these variations analytically in the manner best adapted for computation, are found to depend upon a theory in mechanics, of considerable intricacy, known by the name of the Variation of the Arbitrary Constants . In seeking the means for abridging the severe labour of the calculations, we must separate the general principles on which they are founded from the analytical processes by which they are carried into effect; and in some important problems great advantage is obtained by adapting the investigation to the particular circumstance of the case, and attending solely to the principles of the method in deducing the solution. The author suggests the possibility of simplifying physical astronomy by calling in the aid of only the usual principles of Dynamics, and by setting aside every formula or equation not absolutely necessary for arriving at the final results. The present paper contains a complete determination of the variable elements of the elliptic orbit of a disturbed planet, deduced from three differential equations, that follow readily from the mechanical conditions of the problem. In applying these equations the author observes, the procedure is the same whether a planet is urged by the sole action of the constant force of the sun, or is besides disturbed by the attraction of other bodies revolving round the luminary; the only difference being that, in the first case, the elements of the orbit are all constant, whereas in the other case they are all variable. The success of the method followed by the author is derived from a new differential equation between the time and the area described by the planet in its momentary plane, which greatly shortens the investigation by rendering it unnecessary to consider the projection of the orbit. But the solution given in the present paper, although it makes no reference to the analytical formulæ of the theory of the Variations of the Arbitrary Constants , is no less an application of that method and an example of its utility, and of the necessity of employing it in very complicated problems.

scholarly journals Analisis Konektivitas Wilayah di Kota Denpasar

2018 ◽  
Vol 19 (1) ◽  
pp. 42
Author(s):  
Aprilia Riszi Indah Dewi Shara
Keyword(s):  
Gravity Model ◽  
Regional Planning ◽  
Quantitative Method ◽  
The Other ◽  
Connectivity Analysis ◽  
Centrality Index ◽  
Growth Center ◽  
Gravitation Model

Connectivity analysis is one of the most important things in a regional planning or development. A certain region can be developed properly if the connectivity system of the region is good too. The aim of this research is to identify regional hierarchy, service centers, and inter-regional interactions in each sub-district in Denpasar City. The method used in this research is quantitative method. Data analyzed by using index analysy of centrality, gravitation model, and konig-shimbel. The results showed that based on centrality index and gravity model, West Denpasar District has the highest value compared to the other three districts in Denpasar City. It shows that West Denpasar District is an area with hierarchy I (growth center) Denpasar City. Determination of hinterland-center of Denpasar is based on the availability of facilities in each sub-district. Keywords: connectivity, hierarchy areas, Denpasar City

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Determination of the Burgers vector of a dislocation in a Fe-Mn alloy by weak-beam image in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 330-331
Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose
Keyword(s):  
High Order ◽  
Simulation Technique ◽  
The Other ◽  
Image Simulation ◽  
Diffraction Vector ◽  
Burgers Vector ◽  
Weak Beam ◽  
Beam Image ◽  
Edge Component

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.

Procedures for the Quantitative Determination of Autoprothrombin C

1962 ◽  
Vol 08 (03) ◽  
pp. 434-441 ◽  
Author(s):  
Edmond R Cole ◽  
Ewa Marciniak ◽  
Walter H Seegers
Keyword(s):  
Quantitative Determination ◽  
Plasma Sample ◽  
Quantitative Measure ◽  
The Other ◽  
Clotting Time ◽  
Bovine Plasma ◽  
Autoprothrombin C

SummaryTwo quantitative procedures for autoprothrombin C are described. In one of these purified prothrombin is used as a substrate, and the activity of autoprothrombin C can be measured even if thrombin is in the preparation. In this procedure a reaction mixture is used wherein the thrombin titer which develops in 20 minutes is proportional to the autoprothrombin C in the reaction mixture. A unit is defined as the amount which will generate 70 units of thrombin in the standardized reaction mixture. In the other method thrombin interferes with the result, because a standard bovine plasma sample is recalcified and the clotting time is noted. Autoprothrombin C shortens the clotting time, and the extent of this is a quantitative measure of autoprothrombin C activity.

Determination of Factor XIII Activity and of Factor XIII Inhibitors Using an Ammonium-Sensitive Electrode

1983 ◽  
Vol 50 (02) ◽  
pp. 563-566 ◽  
Author(s):  
P Hellstern ◽  
K Schilz ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Xiii ◽  
Normal Subjects ◽  
The Other ◽  
Activity Measurement ◽  
Factor Xiii Deficiency ◽  
Assay Procedure ◽  
Stabilization Factor ◽  
Release Method ◽  
Sensitive Electrode

SummaryAn assay for rapid factor XIII activity measurement has been developed based on the determination of the ammonium released during fibrin stabilization. Factor XIII was activated by thrombin and calcium. Ammonium was measured by an ammonium-sensitive electrode. It was demonstrated that the assay procedure yields accurate and precise results and that factor XIII-catalyzed fibrin stabilization can be measured kinetically. The amount of ammonium released during the first 90 min of fibrin stabilization was found to be 7.8 ± 0.5 moles per mole fibrinogen, which is in agreement with the findings of other authors. In 15 normal subjects and in 15 patients suffering from diseases with suspected factor XIII deficiency there was a satisfactory correlation between the results obtained by the “ammonium-release-method”, Bohn’s method, and the immunological assay (r1 = 0.65; r2= 0.70; p<0.01). In 3 of 5 patients with paraproteinemias the values of factor XIII activity determined by the ammonium-release method were markedly lower than those estimated by the other methods. It could be shown that inhibitor mechanisms were responsible for these discrepancies.

A NEW APPROACH TO THE STUDY OF COORDINATIVE CONSTRUCTIONS

2019 ◽  
pp. 175-187
Author(s):  
Anna Varnayeva
Keyword(s):  
Characteristic Property ◽  
Mathematical Concept ◽  
The Other ◽  
New Approach ◽  
Logical Aspect ◽  
First Case

Coordinative constructions are traditionally opposed to subordinative constructions. However, this opposition comes down to denial of dependence in coordinative constructions. Thereby the parity of these two constructions does not come to light: subordinative construction can be described without coordinative one. This situation is not improved by detection of a coordinative triangle in all coordinative constructions. The article shows a new approach in the study of coordinative constructions: a coordinative construction is a system; there are not only specific relations – a coordinative triangle, – but also specific elements. Novelty of the study consists in the address to extralinguistic facts, viz. a mathematical concept of a set and its elements. There are a lot of similarities between them. A set in mathematics includes generalizing elements and the composed row in coordinative constructions; in the first case the set is not partitioned, in the second case it is partitioned. In mathematics equivalent components in coordinative constructions correspond to the set elements. A characteristic property in mathematics is homogeneity in coordinative constructions and etc. It is firstly demonstrated, that coordinative and subordinative constructions are correlative and the study of one construction is impossible without the study of the other one. Their parity is shown in coordinative constructions with elements of one set, in subordinative ones with elements of different sets. Cf.: roses and tulips –red roses. In the coordinatiму construction elements of one set are called: «flowers »; in the subordinative construction there are elements of different sets: «flowers » and «colors». It should be noted that the mathematical concept of a set relates to so called logical aspect in linguistics or thinking about reality.

scholarly journals Stiffness Estimation and Equivalence of Boundary Conditions in FEM Models

2021 ◽  
Vol 11 (4) ◽  
pp. 1482
Author(s):  
Róbert Huňady ◽  
Pavol Lengvarský ◽  
Peter Pavelka ◽  
Adam Kaľavský ◽  
Jakub Mlotek
Keyword(s):  
Boundary Condition ◽  
Finite Element ◽  
Boundary Conditions ◽  
Model Updating ◽  
Element Model ◽  
Computational Time ◽  
Stiffness Coefficients ◽  
First Case ◽  
Numerical Approaches

The paper deals with methods of equivalence of boundary conditions in finite element models that are based on finite element model updating technique. The proposed methods are based on the determination of the stiffness parameters in the section plate or region, where the boundary condition or the removed part of the model is replaced by the bushing connector. Two methods for determining its elastic properties are described. In the first case, the stiffness coefficients are determined by a series of static finite element analyses that are used to obtain the response of the removed part to the six basic types of loads. The second method is a combination of experimental and numerical approaches. The natural frequencies obtained by the measurement are used in finite element (FE) optimization, in which the response of the model is tuned by changing the stiffness coefficients of the bushing. Both methods provide a good estimate of the stiffness at the region where the model is replaced by an equivalent boundary condition. This increases the accuracy of the numerical model and also saves computational time and capacity due to element reduction.

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