Search results for "Correlation"

Evolution of Worldwide Stock Markets, Correlation Structure and Correlation Based Graphs

2011

We investigate the daily correlation present among market indices of stock exchanges located all over the world in the time period Jan 1996 - Jul 2009. We discover that the correlation among market indices presents both a fast and a slow dynamics. The slow dynamics reflects the development and consolidation of globalization. The fast dynamics is associated with critical events that originate in a specific country or region of the world and rapidly affect the global system. We provide evidence that the short term timescale of correlation among market indices is less than 3 trading months (about 60 trading days). The average values of the non diagonal elements of the correlation matrix, corre…

2015

The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (hereafter “shell-less”). Recent studies showed that life-history strategies of gekkotan species differ between species with parchment- and rigid-shelled eggshells. Here we test if the three different eggshell types found in the squamates are also associated with different life-history strategies. We fir…

On the Evaluation of Images Complexity: A Fuzzy Approach

2006

The inherently multidimensional problem of evaluating the complexity of an image is of a certain relevance in both computer science and cognitive psychology. Computer scientists usually analyze spatial dimensions, to deal with automatic vision problems, such as feature-extraction. Psychologists seem more interested in the temporal dimension of complexity, to explore attentional models. Is it possible, by merging both approaches, to define an more general index of visual complexity? We have defined a fuzzy mathematical model of visual complexity, using a specific entropy function; results obtained by applying this model to pictorial images have a strong correlation with ones from an experime…

How personality traits and intrinsic personal characteristics influence the consumer's choice of reduced-calorie food

2012

Abstract Nowadays, the consumption of low-calorie foods is being taken into account as a tool for reducing the incidence of certain nutrition-related health disorders. In this context, several factors were used to model low-fat (LF), low-sugar (LS) and high-calorie (HC) food consumption behavior. These factors were: personality traits (neuroticism and conscientiousness), food choice motives (health and weight control) and intrinsic personal characteristics such as self-esteem and satisfaction with life. The results indicate a good fit for the proposed model. Weight control was the best predictor of consumption of this kind of product, and health was a less strong predictor. In addition, cor…

CORRELATION AMONG DYSLEXIA, DYSPRAXIA AND DYSCALCULIA IN STUDENTS WITH LEARNING DYSABILITIES

2016

The article is devoted to evaluate the correlation among dyslexia, dyspraxia and dyscalculia in students with learning dysabilities. There is a point of view that students with learning dysabilities mostly have dyspraxia, but not all of them have dyscalculia or dyslexia. There is a necessity to have theoretical findings and state criteria for evaluation to carry out empirical research. Students with learning dysabilities have difficulties in many areas, but it is not possible to assure that all of them meet the same problems.

The BRICS: an analysis of the correlation of economic development and integration policies

2021

Finite Sample Sizes of the GRS Test in the Presence of Dynamic Correlation and Conditional Heteroskedasticity

2017

This paper investigates the finite sample properties of the widely-used Gibbons, Ross, Shanken (1989) (GRS) test in the presence of both conditional correlation and conditional heteroskedasticity. It finds that the GRS test exhibits serious size distortions resulting in potentially misleading statistical inferences. The correct critical values, as reported in the study, are considerably larger than suggested by the GRS test.

Correlation between Regional Atp and Blood Flow in Tumors and Surrounding Normal Tissue

1994

Various experimental and human tumors are characterized by a marked heterogeneity in the pathophysiologic micromilieu (1, 2). An inadequate and heterogeneous nutritional blood supply has been suggested to explain the non-uniform distribution of oxygen, pH, and high energy phosphates as it has been observed by many investigators (3, 4). Although there is a distinct understanding of the general interrelationships between these parameters (5), little is known about their actual regional correlation, which cannot be assessed by global measurements. With the autoradiographic method for measurement of blood flow (6, 7) and the metabolic imaging with ATP-induced bioluminescence (8, 9) it has becom…

Correlation between relative sunshine and state of the sky

1981

Abstract It is possible to construct a sunshine map referring to a large zone, lacking in a widespread network of recording stations, correlating the relative sunshine with the “state of the sky”, defined by the monthly mean number of the clear, mixed and overcast days, whose data are more largely available. In the correlation here proposed climatological and meteorological factors are introduced in order to express the helioclimatic characteristics of every location. The application to Italy, using the data of the period 1973–1977 provided by the 31 stations of ITAV, has suggested the classification of these stations in seven “helioclimatic groups” characterized by different values of the …

Statement validity assessment: Inter-rater reliability of criteria-based content analysis in the mock-crime paradigm

2005

Methods. Three raters were trained in CBCA. Subsequently, they analysed transcripts of 102 statements referring to a simulated theft of money. Some of the statements were based on experience and some were confabulated. The raters used 4-point scales, respectively, to judge the degree to which 18 of the 19 CBCA criteria were fulfilled in each statement. Results. The analysis of rater judgment distributions revealed that, with judgments of individual raters varying only slightly across transcripts, the weighted kappa coefficient, the product-moment correlation, and the intra-class correlation were inadequate indices of reliability. The Finn-coefficient and percentage agreement, which were cal…