Search results for "Regression Analysis"
showing 10 items of 807 documents
Exploring twitter for csr disclosure: influence of ceo and firm characteristics in latin american companies
2018
Social networks, which are characterised by accessibility and interactivity, offer great potential for dialogue between companies and stakeholders, for example as platforms for publishing information on aspects of corporate social responsibility (CSR). In this paper, we use a synthetic index to analyse levels of CSR disclosure via Twitter, and identify explanatory variables of this disclosure by studying the demographic characteristics of the Chief Executive Officer (CEO) and of the company. This synthetic index was based on data for 93 companies located in the four countries of the Pacific Alliance (Chile, Colombia, Mexico, and Peru), using categories based on the 2016 Global Reporting Ini…
Quantification of intracranial contribution to rheoencephalography by a numerical model of the head
2000
Abstract Objectives : Partial contributions of intracranial and extracranial circulation to rheoencephalography (REG) remain uncertain. The main goal of this work is to determine theoretically the capability of REG techniques to reflect intracranial blood flow. Methods : Head and current injection electrodes were computationally modeled to assess REG sensitivity to brain and scalp conductivity changes. Data obtained were related to tissue perfusions to calculate the partial contribution of cerebral blood perfusion to REG I, REG II and monopolar REG and to assess their amplitudes. Results : When REG I and monopolar REG were used, the theoretical maximum of intracranial contribution was reach…
Application of Molecular Topology to the Prediction of the Reaction Yield and Anticancer Activity of Imidazole and Guanidine Derivatives
2013
In this study molecular topology based QSAR has been applied to predict the reaction yield and anticancer activity of 18 imidazole and guanidine derivatives. Four properties were evaluated, namely reaction yield, anti prostatic-cancer activity, anti breast-cancer activity and anti lung-cancer activity. The four models have been validated by both internal and cross validation, and also by randomness tests. The results obtained are in full agreement with the experimental results and confirm the precision, accuracy and robustness of the method followed. After carrying out a virtual screening upon such models, new imidazole and guanidine derivatives with potential anticancer activity are propos…
The relationship among beliefs about problem solving, epistemological beliefs, grade level, sex, and problem solving achievement: A study in secondar…
2020
The first purpuse of this investigation was to study the effects of sex and grade level on secondary students’ beliefs about epistemology and problem solving. The second purpuse was to analyze the contribution of both belief systems, grade level, and sex to problem solving achievement. One hundred and forty-four High School students, 9th and 11th grade students, took part in the study. Two questionnaires (Schommer and StageKloosterman’s questionnaires) and a problem solving test (two word problems of the PISA tests) were administered to these students. Two ANOVAs, an ANCOVA, and a multiple regression analysis were carried out from data obtained in the investigation. In the light of the fore…
Sickness presenteeism of German teachers: prevalence and influencing factors
2016
AbstractThe aim of the present study was to investigate teachers’ sickness presenteeism (SP). We examined the prevalence of SP in a sample of teachers as well as work-related and health-related influencing factors of teachers’ SP. We used a cross-sectional study design. Teachers working at different types of schools in Rhineland-Palatinate (Germany) participated in an online survey. We used Pearson’s Chi-squared test (in case of categorical variables) or Mann–Whitney-U-test (in case of continuous variables) to test for differences between SP and sociodemographic/work-related/health-related factors. Factors influencing SP were identified using multivariable logistic regression analyses. Nine…
Digital Devices Use and Language Skills in Children between 8 and 36 Month
2020
Background: Over the past decade, the use of digital tools has grown and research evidence suggests that traditional media and new media offer both benefits and health risks for young children. The abilities to understand and use language represent two of the most important competencies developed during the first 3 years of life through the interaction of the child with people, objects, events, and other environmental factors. The main goal of our study is to evaluate the relationship between digital devices use and language abilities in children between 8 and 36 month, also considering the influence of several factors. Materials and Methods: We conducted a cross-sectional observational stu…
Modeling Return to Education in Heterogeneous Populations: An Application to Italy
2019
The Mincer human capital earnings function is a regression model that relates individual’s earnings to schooling and experience. It has been used to explain individual behavior with respect to educational choices and to indicate productivity on a large number of countries and across many different demographic groups. However, recent empirical studies have shown that often the population of interest embed latent homogeneous subpopulations, with different returns to education across subpopulations, rendering a single Mincer’s regression inadequate. Moreover, whatever (concomitant) information is available about the nature of such a heterogeneity, it should be incorporated in an appropriate ma…
A Method Based on Multi-source Feature Detection for Counting People in Crowded Areas
2019
We propose a crowd counting method for multisource feature fusion. Image features are extracted from multiple sources, and the population is estimated by image feature extraction and texture feature analysis, along with for crowd image edge detection. We count people in high-density still images. For instance, in the city’s squares, sports fields, subway stations, etc. Our approach uses a still image taken by a camera on a drone to appraise the count in the population density image, using a kind of sources of information: HOG, LBP, CANNY. We furnish separate estimates of counts and other statistical measurements through several types of sources. Support vector machine SVM, classification an…
Differences in parasite susceptibility and costs of resistance between naturally exposed and unexposed host populations
2009
It is generally assumed that resistance to parasitism entails costs. Consequently, hosts evolving in the absence of parasites are predicted to invest less in costly resistance mechanisms than hosts consistently exposed to parasites. This prediction has, however, rarely been tested in natural populations. We studied the susceptibility of three naïve, three parasitized and one recently isolated Asellus aquaticus isopod populations to an acanthocephalan parasite. We found that parasitized populations, with the exception of the isopod population sympatric with the parasite strain used, were less susceptible to the parasite than the naïve populations. Exposed but uninfected (resistant) isopods f…
Strategic and motivational factors as predictors of pre-service primary teachers's success in problem solving
2014
En este trabajo se presenta una investigación descriptiva que muestra las relaciones entre cinco factores motivacionales y estratégicos (planificación, estrategias cognitivas, autocontrol, esfuerzo y autoeficacia) y el rendimiento en la resolución de problemas. Se administró a 66 maestras y maestros de primaria en formación un cuadernillo con dos problemas (problema 1 y problema 2) y el test de O'Neil y Schacter. Los resultados de los análisis de regresión múltiple ponen de manifiesto que: a) planificación, esfuerzo y autoeficacia son predictores significativos de las puntuaciones de las puntuaciones del problema de estructura simple (problema 1); b) esfuerzo, autoeficacia y estrategias cog…