The optimal investment problem is studied for a continuous time incomplete market model. It is assumed that the risk-free rate, the appreciation rates, and the volatility of the stocks are all random; they are independent from the driving Brownian motion, and they are currently observable. It is shown that some weakened version of Mutual Fund Theorem holds for this market for general class of utilities. It is shown that the supremum of expected utilities can be achieved on a sequence (...) of strategies with a certain distribution of risky assets that does not depend on risk preferences described by different utilities. (shrink)

In 2002, Yorioka introduced the σ-ideal ${{\mathcal {I}}_f}$ for strictly increasing functions f from ω into ω to analyze the cofinality of the strong measure zero ideal. For each f, we study the cardinal coefficients (the additivity, covering number, uniformity and cofinality) of ${{\mathcal {I}}_f}$.

We propose a method for estimating subjective beliefs, viewed as a subjective probability distribution. The key insight is to characterize beliefs as a parameter to be estimated from observed choices in a well-defined experimental task and to estimate that parameter as a random coefficient. The experimental task consists of a series of standard lottery choices in which the subject is assumed to use conventional risk attitudes to select one lottery or the other and then a series of betting choices (...) in which the subject is presented with a range of bookies offering odds on the outcome of some event that the subject has a belief over. Knowledge of the risk attitudes of subjects conditions the inferences about subjective beliefs. Maximum simulated likelihood methods are used to estimate a structural model in which subjects employ subjective beliefs to make bets. We present evidence that some subjective probabilities are indeed best characterized as probability distributions with non-zero variance. (shrink)

We develop an extension of the familiar linear mixed logit model to allow for the direct estimation of parametric non-linear functions defined over structural parameters. Classic applications include the estimation of coefficients of utility functions to characterize risk attitudes and discounting functions to characterize impatience. There are several unexpected benefits of this extension, apart from the ability to directly estimate structural parameters of theoretical interest.

Evolutionary gradualism, the randomness of mutations, and the hypothesis that natural selection exerts a pervasive and substantial influence on evolutionary outcomes are pair-wise logically independent. Can the claims about selection and mutation be used to formulate an argument for gradualism? In his Genetical Theory of Natural Selection, R.A. Fisher made an important start at this project in his famous “geometric argument” by showing that a random mutation that has a smaller effect on two or more phenotypes will have a (...) higher average fitness than a random mutation that has a larger phenotypic effect. Motoo Kimura’s demonstration that a gene’s probability of fixation depends on both the selection coefficient and the effective population size shows that Fisher’s argument for gradualism was mistaken. Here we analyze Fisher’s argument and explain how Kimura’s theory leads to a conclusion that Fisher did not anticipate. We identify a fallacy that reasoning about fitness differences and their evolutionary consequences should avoid. We then distinguish forward-directed from backward-directed versions of gradualism. The backward-directed thesis about a single mutation may be correct, but the forward-directed thesis is not. After that we consider a sequence of random mutations that all affect the same cluster of phenotypes and Allen Orr’s idea that there is an optimal sequence of mutation sizes, moving from larger to smaller as the population approaches a fixed optimum. This provides a likelihood justification for a forward-directed version of gradualism when there is a fixed optimum, but it also provides an argument against forward-directed gradualism if the optimum shifts substantially as the population evolves. Finally, we consider whether genome-wide association studies (GWASs) can furnish empirical evidence that bears on the truth of gradualism. The version of gradualism that GWASs directly bear on concerns the phenotypic effect size of a gene after it arises by mutation and has reached an appreciable frequency, not the phenotypic size of the mutation event itself. (shrink)

The problem of adaptive finite-time fault-tolerant control and output constraints for a class of uncertain nonlinear half-vehicle active suspension systems are investigated in this work. Markovian variables are used to denote in terms of different random actuators failures. In adaptive backstepping design procedure, barrier Lyapunov functions are adopted to constrain vertical motion and pitch motion to suppress the vibrations. Unknown functions and coefficients are approximated by the neural network. Assisted by the stochastic practical finite-time theory and FTC theory, (...) the proposed controller can ensure systems achieve stability in a finite time. Meanwhile, displacement and pitch angle in systems would not violate their maximum values, which imply both ride comfort and safety have been enhanced. In addition, all the signals in the closed-loop systems can be guaranteed to be semiglobal finite-time stable in probability. The simulation results illustrate the validity of the established scheme. (shrink)

We present a review of part of the results obtained by the authors for the statistics of coherent radiation propagating in a random medium both in the framework of diagrammatic techniques and random matrix theory. Distribution functions for the total transmission coefficient and the angular transmission coefficient for the diffusive transport and the crossover between the diffusive and ballistic regimes are obtained.

Outside directors’ regular board meeting attendance is important in improving the effectiveness of a governance system. Such attendance is evidence of their commitment to the firm as key other players in monitoring and decision making. Using a unique dataset for Korean firms, and three-level random coefficients models, we find that, foreign outside directors, an independent appointment process, professional knowledge of business operations and accumulated firm-specific knowledge are important factors that affect outside directors’ attendance of board meetings. The results (...) also confirm that both outside directors’ personal characteristics and the social context are crucial in understanding their board meeting attendance. Further analysis shows that a positive corporate environment that supports the outside director system encourages outside directors’ attendance at board meetings. (shrink)

Building on the broaden-and-build theory of positive emotions and on social role theory, this research investigates the linkages among prior job satisfaction, voluntary workplace green behavior, and subsequent job satisfaction as dependent on work group gender composition. With a multi-source, multi-time dataset, our random coefficient modeling demonstrated that job satisfaction positively predicts VWGB and that this pattern is more salient in work groups with more females. In addition, while VWGB does not yield job satisfaction in a subsequent time period, (...) this positive linkage occurs in work groups with fewer females. This research offers theoretical implications for understanding the internal states and personal benefits of voluntary green performers as well as for the role of work group gender diversity on the linkages between prior job satisfaction and VWGB and between VWGB and subsequent job satisfaction. Our findings also illuminate the practical benefits of environmentally sustainable organizations. (shrink)

Children who experience well-being are engaging more confidently and positively with their caregiver and peers, which helps them to profit more from available learning opportunities and support current and later life outcomes. The goodness-of-fit theory suggests that children’s well-being might be a result of the interplay between their temperament and the environment. However, there is a lack of studies that examined the association between children’s temperament and well-being in early childhood education and care, and whether this association is affected by (...) ECEC process quality. Using a multilevel random coefficient approach, this study examines the association between toddlers’ temperament and well-being in Norwegian ECEC and investigates whether process quality moderates this association. Results reveal an association between temperament and well-being. Staff-child conflict moderates the association between shyness and well-being, and between activity and well-being. Moreover, high emotional behavioral support moderates the association between activity and well-being. Extra attention should be paid by the staff to these children’s needs. (shrink)

The present research aimed to provide a more holistic analysis of stressful experiences in sport by examining how stress appraisal, coping and emotion are dynamically inter-related constructs and the extent to which their dynamic relationship is associated with objective performance. Based on process-oriented methods, two studies were conducted with elite athletes in order to investigate the dynamic relationship between these constructs and performance in highly demanding sport situations (Study 1: simulated competitive fencing matches during a training session; Study 2: real-life (...) competitive fencing matches during an international competition). The results of the random coefficient regression models emphasise the dynamic nature of the relationship between stress appraisal, coping behaviour, emotion and objective performance over the course of fencing matches. They allowed identification of additional mediating effects of coping and emotion within dynamic relationships between stress appraisal and performance. These studies contribute to a deeper understanding of psychological adaptation in performance environments. The implications of the findings are discussed in relation to the design of effective coping interventions to support the learning of performance-related coping skills and the attainment of performance goals among individuals in highly demanding environments. (shrink)

Integrating the categorization-elaboration model (CEM), resource complementarity, and human capital perspectives, we investigate whether the founder CEO’s human capital resources can influence the effect of workforce gender diversity, an untapped strategic resource, on venture firm performance. Our main focus lies on knowledge- and technology-intensive venture firms, and we propose that both workforce gender diversity and the CEO’s human capital resources jointly influence venture firm performance. We identify the specific functional impacts of the founder CEO's human capital, encompassing entrepreneurial experience, human (...) resource (HR) management experience, and same-industry experience. Analyzing 1413 venture firms utilizing multilevel analysis (random coefficient modeling), we find that gender diversity does not significantly affect venture firm performance. Nevertheless, the founder CEO’s entrepreneurial experience exerts a positive impact on the interplay between gender diversity and venture firm performance. These findings underscore the strategic role of the founder CEO’s human capital resources in moderating the effects of gender diversity, making significant contributions to the diversity and strategic human capital resource literature. (shrink)

In the past 2 decades latent variable modeling has become a standard tool in the social sciences. In the same time period, traditional linear structural equation models have been extended to include non-linear interaction and quadratic effects (e.g., Klein and Moosbrugger, 2000 ), and multilevel modeling (Rabe-Hesketh et al., 2004 ). We present a general non-linear multilevel structural equation mixture model (GNM-SEMM) that combines recent semiparametric non-linear structural equation models (Kelava and Nagengast, 2012 ; Kelava et al., 2014 ) with (...) multilevel structural equation mixture models (Muthén and Asparouhov, 2009 ) for clustered and non-normally distributed data. The proposed approach allows for semiparametric relationships at the within and at the between levels. We present examples from the educational science to illustrate different submodels from the general framework. (shrink)

The basic assumptions in the physical theory of Brownian motion are analized and the arbitrary character of certain aspects of the current theories is emphasized. The most serious limitations of the theory arise from the fact that in the theory, the elementary processes of the individual collisions are nowhere discussed. However, it is shown that the encounters between stars under their Newtonian inverse square attractions considered in Stellar Dynamics provides, in virtue of the peculiar character of inverse square forces, a (...) case in Brownian motion in which all phases of the problem can be explicitly analyzed. Thus, the separation, of the effects of encounters into a dynamical friction and a random fluctuation is explicitly demonstrated from a direct analysis based on the dynamics of the encounters themselves; similary, the ratio of the frictional to the diffusion coefficients can also be shown to have the value which is required for the restoration and maintenance of a Max‐wellian distribution of velocities from any arbitrary initial distribution. ‐ S. C. (shrink)

Development and targeting efforts by academic organizations to effectively promote research integrity can be enhanced if they are able to collect reliable data to benchmark baseline conditions, to assess areas needing improvement, and to subsequently assess the impact of specific initiatives. To date, no standardized and validated tool has existed to serve this need. A web- and mail-based survey was administered in the second half of 2009 to 2,837 randomly selected biomedical and social science faculty and postdoctoral fellows at 40 (...) academic health centers in top-tier research universities in the United States. Measures included the Survey of Organizational Research Climate (SORC) as well as measures of perceptions of organizational justice. Exploratory and confirmatory factor analyses yielded seven subscales of organizational research climate, all of which demonstrated acceptable internal consistency (Cronbach’s α ranging from 0.81 to 0.87) and adequate test–retest reliability (Pearson r ranging from 0.72 to 0.83). A broad range of correlations between the seven subscales and five measures of organizational justice (unadjusted regression coefficients ranging from 0.13 to 0.95) document both construct and discriminant validity of the instrument. The SORC demonstrates good internal (alpha) and external reliability (test–retest) as well as both construct and discriminant validity. (shrink)

Consanguineous marriage is traditionally common throughout the Eastern Mediterranean region, especially in the mainly Muslim countries. To date, there is little information on consanguinity in Yemen. The aim of this study was to ascertain the rate of consanguineous marriage and average coefficient of inbreeding in Sanaa City by means of a multi-stage random sampling technique. A total of 1050 wives and husbands were interviewed on consanguinity in their households. The total incidence of consanguinity was 44·7% (95% CI 41·7–47·7%) with (...) first-cousin marriages constituting 71·6% of the total consanguineous marriages and 32% of all marriages. Paternal parallel first cousins (Type I) accounted for 49% of first-cousin marriages. The average coefficient of inbreeding (F) was 0·02442. The incidence of consanguinity is relatively high in Yemen with predominantly first-cousin marriage. This might be related to the deeply rooted social and cultural beliefs in the country. (shrink)

Publication date: 16 April 2018 Source: Author: Amjad Hedayat, Fatemeh Nemati Sogolitappeh, Reza Shakeri, Mohamad Abasifard, Mohamad Khaledian One of the concerns of the organization and management experts is to identify effective factors on organization performance and finding solutions to improve organization performance. The present study was done to analyse the relationship between organizational commitment and job satisfaction in visiting lectures of Payam Nour University. Statistical population of this research includes visiting lectures of Ghorveh town who were teaching in the (...) academic year of 2016-2017. Sample size of 60 participants was selected by simple random sampling. To collect data, Meyer and Allen organizational commitment questionnaire and Field and Rothe job satisfaction questionnaire were used. The research method is correlation which is incorporated in the area of applied studies to analyse data, descriptive statistics, and inferential statistics were utilized. The findings show that there is positive and significant relationship between organizational commitment and job satisfaction. Regression coefficient shows that organizational commitment predicts 42.2 % of the job satisfaction changes. (shrink)

Nothing, one day, seemed more imperative to me than the project of composing a book whose fiction would be constructed not as the representation of some preexistent entity, real or imaginary, but rather on the basis of certain specific mechanisms of generation and selection. The principle of selection may be called overdetermination. It requires that every element in the text have at least two justifications. In this perspective, each element is invested with a coefficient of overdetermination. If there is a (...) choice to be made between two overdetermined elements, the one with the highest coefficient of overdetermination will always be chosen. This principle, as we might expect, was not elected at random: it corresponds to any text construed as nonlinear. Take, for example, the simplest element, with a coefficient of two. A double relation connects it with the text: the one due to its place in the written line , and the one linking it with some other element in the text . By operating at a maximum level of multiple determinations, the text is elaborated by means of a maximum number of transversal relations, in a field diametrically opposed to the realm of the linear. Jean Ricardou is equally well known for his fiction, including L'Observatoire de Cannes , La Prise de Constantinople , Les Lieux-dits , and Les Révolutions Minuscules , and his criticism, including Problèmes du Nouveau Roman , Pour une Theorie du Nouveau Roman , and Le Nouveau Roman , LE PARADIGME d' Albert Ayme , and a collection of essays, Nouveaux Problèmes du Roman. His "Composition Discomposed" appeared in the Autumn 1976 issue of Critical Inquiry. Erica Freiberg regularly translates Jean Ricardou's works. She holds degrees in French and Italian, philosophy and modern literature from the University of Paris and the University of Geneva. (shrink)

Teaching while managing instructional workload is causal to the teaching-learning process. The study determined the teachers' instructional workload management to the teachers' teaching efficacy. It was conducted in a community college in Tangub City, Misamis Occidental. The descriptive-correlational design was used in the study. There were 15 program heads and 361 students who served as the respondents selected through a stratified random sampling technique. The researcher-made Teachers' Instructional Workload Management and Teachers' Teaching Efficacy Questionnaires were used as research instruments. (...) Mean, Standard Deviation, and Pearson Product-Moment Correlation Coefficient were used as statistical tools to analyze the data gathered. Results revealed that the teachers were very good in their instructional workload management. The teachers' teaching efficacy was very high. Some aspects of the teachers' instructional workload management like the preparation of instructional materials influenced the teachers' administration of assessment tasks and classroom management. Their conduct of consultation also influenced the administration of assessment tasks. Moreover, their submission of academic reports influenced the administration of assessment tasks and school resource utilization. The workload management of teachers play a crucial role in shaping teachers' teaching efficacy. It is recommended for teachers to manage their workload proactively since it can impact their teaching efficacy. (shrink)

Teens are extremely important targets for marketers because: they influence their parents’ spending, spend a lot of money in the future, and they are trendsetters. Some reason that make a brand popular among teens’ are: “quality”, “it’s for people my age”, “advertising”, “if cool friends or peers use it”, and “if a cool celebrity uses it”. Thus, it appears that advertising, peers, and celebrity or reference group have the potential to contribute to brand choice among teens. The objective of this (...) research was to know how reference group influence teenagers’ purchase intention and purchase behavior, especially in food supplement product. Sample was collected as a purposive random sampling method. This study used a questionnaire survey to investigate the influence of reference group in teenagers’ purchase intention and purchase behavior. The questionnaire was adopted from Martin and Bush (2000). Data was analyzed by simple regression analysis. By analyzing the standardized beta coefficients and the significance levels of each reference group, the predictive ability of potential reference group influence on teenagers’ purchase intention and purchase behavior can be examined. The findings suggest that reference group have a significant influence toward food supplement purchase intention and purchase behavior in Teenagers. All reference groups have a significant influence toward food supplement purchase intention, but only experts and celebrity have a significant influence toward purchase behavior in teenagers’. The findings also suggest that reference groups doesn’t plays an important role to influence purchase intention and purchase behavior in Teenagers”. (shrink)

Social desirability bias is a pervasive measurement challenge in the social sciences and survey research. More clarity is needed to understand the performance of social desirability scales in diverse groups, contexts, and cultures. The present study aims to contribute to the international literature on social desirability measurement by examining the psychometric performance of a short version of the Marlowe-Crowne Social Desirability Scale in a nationally representative sample of teachers in Kazakhstan. A total of 2,461 Kazakhstani teachers completed the MCSDS – (...) Form C in their language of choice. The results failed to support the theoretical unidimensionality of the original scale. Instead, the results of Random Intercept Item Factor Analysis model suggest that the scale answers depend more on the method factor rather than the substantial factor that represents SDB. In addition, an alternative explanation indicates that the scale seems better suited to measuring two SDB correlated factors: attribution and denial. Internal consistency coefficients demonstrated unsatisfactory reliability scores for the two factors. The Kazakhstani version of the MCSDS – Form C was invariant across geographic location, language, and partially across age groups. However, no measurement invariance was demonstrated for gender. Despite these limitations, the analysis of the Kazakhstani version of the MCSDS – Form C presented in this study constitutes a first step in facilitating further research and measurement of SDB in post-Soviet Kazakhstan and other collectivist countries. (shrink)

Supervision of teachers is essential for ensuring effective educational practices, fostering professional development, and achieving student success. The study determined the relationship of program heads' supervisory practices to the teachers’ teaching efficacy. It was conducted in a community college in Tangub City, Misamis Occidental. The descriptive-correlational design was used in the study. There were 146 faculty and 361 students who served as the respondents selected through a stratified random sampling technique. The adapted Program Heads’ Supervisory Practices and researcher-made Teachers’ (...) Teaching Efficacy Questionnaires were used as research instruments. Mean, Standard Deviation, and Pearson Product-Moment Correlation Coefficient were used as statistical tools to analyze the data gathered. Results revealed that the program heads were good in their supervisory practices. The teachers’ teaching efficacy was very high. The program heads’ supervisory practices did not influence the teacher’s teaching efficacy. The strategies employed by program heads in their supervisory roles do not always translate into improved teaching efficiency. The study's findings indicate that program heads need to adopt more responsive and tailored supervisory practices that directly address the specific needs of teachers to enhance teaching efficacy. This may involve integrating targeted professional development focused on practical classroom strategies and fostering peer collaboration to share best practices. Program heads may prioritize open communication and continuous feedback mechanisms to better align their supervisory approaches with the realities of classroom instruction, ensuring that support translates into improved teaching efficiency. (shrink)

In face recognition systems, highly robust facial feature representation and good classification algorithm performance can affect the effect of face recognition under unrestricted conditions. To explore the anti-interference performance of convolutional neural network reconstructed by deep learning framework in face image feature extraction and recognition, in the paper, first, the inception structure in the GoogleNet network and the residual error in the ResNet network structure are combined to construct a new deep reconstruction network algorithm, with the random gradient descent (...) and triplet loss functions as the model optimizer and classifier, respectively, and it is applied to the face recognition in Labeled Faces in the Wild face database. Then, the portrait pyramid segmentation and local feature point segmentation are applied to extract the features of face images, and the matching of face feature points is achieved using Euclidean distance and joint Bayesian method. Finally, Matlab software is used to simulate the algorithm proposed in this paper and compare it with other algorithms. The results show that the proposed algorithm has the best face recognition effect when the learning rate is 0.0004, the attenuation coefficient is 0.0001, the training method is SGD, and dropout is 0.1, and the algorithm proposed in this paper has the largest mean average precision compared to other CNN algorithms. The correct rate of face feature matching of the algorithm proposed in this paper is 84.72%, which is higher than LetNet-5, VGG-16, and VGG-19 algorithms, the correct rates of which are 6.94%, 2.5%, and 1.11%, respectively, but lower than GoogleNet, AlexNet, and ResNet algorithms. At the same time, the algorithm proposed in this paper has a faster matching time and a higher correct matching rate than the joint Bayesian method, indicating that the deep reconstruction network algorithm proposed in this paper can be used in face image recognition, FE, and matching, and it has strong anti-interference. (shrink)

Consumers play an important role as one of the main actors in food safety social co-governance. To create a pattern of food safety social co-governance, the active and effective participation of consumers is critical. To encourage consumers to participate in food safety social co-governance voluntarily and positively, we attempted to develop and preliminarily validate a multidimensional questionnaire on consumer psychological capital that could be used to measure the degree of consumer participation in food safety social co-governance. The aim of the (...) initial sample and test sample 2 was to investigate the factor structure of a preliminary measure of consumer psychological capital. A 4-factor model with 23 items explained 61.05% of the total variance in item scores. The aim of test sample 3 was to measure the retest reliability. Test sample 4 was randomly allocated to the modeling sample and validation sample to verify questionnaire reliability and validity. Convergent validity, discriminant validity, and the internal inconsistency coefficients of the questionnaire were assessed in the modeling sample. While processing CFA, we deleted 9 items with small standardized factor loadings. The remaining 14 items in the final revised 4-factor model included self-efficacy, resilience, hope, and optimism. The fit indices of the revised four-factor model and second-order factor model in the modeling sample revealed an acceptable model fit. The convergent validity and discriminant validity of the revised model were good and acceptable, respectively. A cross-validation procedure confirmed the appropriateness of the revised four-factor model and second-order factor model in the validation sample. The cross-validation results confirmed that the fit indices of the revised four-factor model fitted the data well and the second-order factor model in the validation sample reached acceptable values. We concluded that the questionnaire developed in this study had good reliability and stable and acceptable construct validity. It could provide a theoretical basis for measuring psychological capital in food safety co-governance. (shrink)

Background Care is the basis of the nursing profession and nurse’s caring behavior is one of the important factors in patient satisfaction. On the other hand, psychological empowerment can improve the provision of care services, and leaders have a significant impact on the behavior of followers. This study determined the correlation between ethical leadership, psychological empowerment, and caring behavior from nurses’ perspective. Methods This cross-sectional descriptive study was conducted in 2019. A total of 200 nurses were selected by stratified (...) class='Hi'>random sampling. Data were collected with ethical leadership, caring behavior and psychological empowerment questionnaires and analyzed with descriptive statistics (mean and standard deviation, frequency distribution) and inferential statistics (Pearson correlation coefficient, regression, and t-test) using SPSS20. Results The findings showed a significant correlation between ethical leadership, psychological empowerment (P < 0.001, r = 0.24) and caring behavior of nurses (P < 0.001, r = 0.25). Also, there was a significant correlation between psychological empowerment and nurses’ caring behavior (P = 0.002, r = 0.21). The regression analysis showed that ethical leadership and psychological empowerment are a predictor of caring behavior of nurses. Conclusion Applying an ethical leadership style by nursing managers can lead to nurses’ improved psychological empowerment and caring behaviors and ultimately, patient care quality. Thus, considering guidelines at the team and organizational levels and programs such as providing workshops and periodic counseling to cultivate ethical nurse leadership can lead to better caring behavior. (shrink)

In this paper we present the results of two experiments. The first is on the categorization of texture words in the English language. The goal was to determine whether there is a common basis for subjects' groupings of words related to visual texture, and if so, to identify the underlying dimensions used to categorize those words.Eleven major clusters were identified through hierarchical cluster analysis, ranging from “random” to “repetitive”. These clusters remained intact in a multidimensional scaling solution. The stress (...) for a three‐dimensional solution obtained through multidimensional scaling was 0.18, meaning that 82% of the variance in the data is explained through the use of three dimensions. It appears that the major dimensions of texture descriptors are repetitive versus nonrepetitive; linearly oriented versus circularly oriented; and simple versus complex.In the second experiment we measured the strength of association between texture words and texture images. The goal was to determine whether there is any systematic correspondence between the domains of texture words and texture images. Pearson's coefficient of contingency, a measure of the strength of association, was found to be 0.63 for words corresponding to given images and 0.56 for images corresponding to given words. Thus the texture categories in the verbal space and those in the visual space are strongly tied.In sum, our two experiments show (a) that despite the tremendous variety in the words we have to describe textures, there is an underlying structure to the lexical space which can be derived from the experimental data; and (b) that the association between a category of words and a category of images was strongest when both categories represent the same underlying property. This suggests that subjects' organizations of texture terms are systematically tied to their organization of texture images. (shrink)

In recent years, functional connectivity in the developmental science received increasing attention. Although it has been reported that the anatomical connectivity in the preterm brain develops dramatically during the last months of pregnancy, little is known about how functional and effective connectivity change with maturation. The present study investigated how effective connectivity in premature infants evolves. To assess it, we use EEG measurements and graph-theory methodologies. We recorded data from 25 preterm babies, who underwent long-EEG monitoring at least twice during (...) their stay in the NICU. The recordings took place from 27 weeks postmenstrual age until 42 weeks PMA. Results showed that the EEG-connectivity, assessed using graph-theory indices, moved from a small-world network to a random one, since the clustering coefficient increases and the path length decreases. This shift can be due to the development of the thalamocortical connections and long-range cortical connections. Based on the network indices, we developed different age-prediction models. The best result showed that it is possible to predict the age of the infant with a root mean-squared error equal to 2.11 weeks. These results are similar to the ones reported in the literature for age prediction in preterm babies. (shrink)

This article introduces a simple and effective new algorithm for image encryption using a chaotic system which is based on the magic squares. This novel 3D chaotic system is invoked to generate a random key to encrypt any color image. A number of chaotic keys equal to the size of the image are generated by this chaotic system and arranged into a matrix then divided into non-overlapped submatrices. The image to be encrypted is also divided into sub-images, and each (...) sub-image is multiplied by a magic matrix to produce another set of matrices. The XOR operation is then used on the resultant two sets of matrices to produce the encrypted image. The strength of the encryption method is tested in two folds. The first fold is the security analysis which includes key space analysis and sensitivity analysis. In the second fold, statistical analysis was performed, which includes the correlation coefficients, information entropy, the histogram, and analysis of differential attacks. Finally, the time of encryption and decryption was computed and show very good results. (shrink)

This study aims to predict the shear strength of reinforced concrete deep beams based on artificial neural network using four training algorithms, namely, Levenberg–Marquardt, quasi-Newton method, conjugate gradient, and gradient descent. A database containing 106 results of RC deep beam shear strength tests is collected and used to investigate the performance of the four proposed algorithms. The ANN training phase uses 70% of data, randomly taken from the collected dataset, whereas the remaining 30% of data are used for the algorithms’ (...) evaluation process. The ANN structure consists of an input layer with 9 neurons corresponding to 9 input parameters, a hidden layer of 10 neurons, and an output layer with 1 neuron representing the shear strength of RC deep beams. The performance evaluation of the models is performed using statistical criteria, including the correlation coefficient, root mean square error, mean absolute error, and mean absolute percentage error. The results show that the ANN-CG model has the best prediction performance with R = 0.992, RMSE = 14.02, MAE = 14.24, and MAPE = 6.84. The results of this study show that the ANN-CG model can accurately predict the shear strength of RC deep beams, representing a promising and useful alternative design solution for structural engineers. (shrink)

Background Many studies have investigated the adherence to professional codes of ethics by nurses. However, no study has explicitly examined the relationship between workload and adherence to professional codes of ethics among Iranian nurses. Objective This study aimed to explore the relationships between workload and adherence to professional codes of ethics among a sample of Iranian nurses. Materials and Methods A cross-sectional descriptive study was conducted on 213 nurses who were randomly selected from the different wards of Shahid Beheshti Hospital (...) of Kashan, Iran. Data collection instruments included a personal characteristics questionnaire, the Nursing Ethics Questionnaire, and the National Aeronautics and Space Administration Task Load Index. The Chi-square, the Spearman correlation coefficient, the Kruskal–Wallis, and Mann–Whitney U tests were used to analyze the data. Results A majority of nurses were females, married, and permanently employed. The mean of the overall perceived workload and adherence to professional codes of ethics were 76.36 ± 13.64 and 13.98 ± 2.58, that were at high and moderated level, respectively. Spearman correlation test showed no significant correlation between perceived workload and adherence to professional codes of ethics. A significant difference was found between the mean scores of adherence to professional codes of ethics in nurses working in different departments. Conclusion Participating nurses perceived high levels of workload but their mean adherence to professional codes of ethics was at a moderate level. The perceived workload was indirectly correlated with adherence to professional codes of ethics. (shrink)

We revisit the nonrelativistic problem of a bound, charged particle subject to the random zero-point radiation field, with the purpose of revealing the mechanism that takes it from the initially classical description to the final quantum-mechanical one. The combined effect of the zpf and the radiation reaction force results, after a characteristic time lapse, in the loss of the initial conditions and the concomitant irreversible transition of the dynamics to a stationary regime controlled by the field. In this regime, (...) the canonical variables x, p become expressed in terms of the dipolar response functions to a set of field modes. A proper ordering of the response coefficients leads to the matrix representation of quantum mechanics, as was proposed in the early days of the theory, and to the basic commutator x^,p^=iħ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left[ {\hat{x}},{\hat{p}}\right] =i\hbar$$\end{document}. Further, the connection with the corresponding Fokker–Planck equation valid in the Markov approximation, allows one to obtain the radiative corrections of qed. These results reaffirm the essentially electrodynamic and stochastic nature of the quantum phenomenon, as proposed by stochastic electrodynamics. (shrink)

For the safe and economical construction of embankment dams, the mechanical behaviour of the rockfill materials used in the dam’s shell must be analyzed. The characterization of rockfill materials with specified shear strength is difficult and expensive due to the presence of particles greater than 500 mm in diameter. This work investigates the feasibility of using an extreme gradient boosting computing paradigm to estimate the shear strength of rockfill materials. To train and validate the proposed XGBoost model, a total of (...) 165 databases obtained from the literature are chosen. The XGBoost model was compared against support vector machine, adaptive boosting, random forest, and K-nearest neighbor models described in the literature. XGBoost beats SVM, RF, AdaBoost, and KNN models in terms of performance evaluation metrics such as coefficient of determination, Nash–Sutcliffe coefficient, and error in the root mean square ratio to the standard deviation of the measured data. The results demonstrated that the XGBoost model has the highest prediction performance with, followed by the SVM model with, RF, the AdaBoost model with and the KNN model with. A sensitivity analysis has been conducted to ascertain the impact of each investigated input parameter. This study demonstrates that the established XGBoost model for estimating the shear strength of rockfill materials is reliable. (shrink)

With the increasing volume of data transmission through insecure communication channels, big data security has become one of the important concerns in the cybersecurity domain. To address these concerns and keep data safe, a robust privacy-preserving cryptosystem is necessary. Such a solution relies on chaos encryption algorithms over standard cryptographic methods that possess multistage encryption levels, including high speed, high security, low compute overheads, and procedural power, among other characteristics. In this work, a secure image encryption scheme is proposed using (...) linear feedback shift register and chaos-based quantum chaotic map. The focus of the scheme is mainly dependent on the secret keys from the input of the algorithm. The threat landscape, the statistical test analysis, along critical comparisons with other schemes indicate that the presented algorithm is significantly secure and is resistant to a wide range of different attacks such as differential and statistical attacks. The proposed method has sufficiently higher sensitivity and security when compared to existing encryption algorithms. Several security parameters validated the security of proposed work such as correlation coefficient analyses among the neighboring pixels, entropy, the number of pixels change rate, unified average change intensity, mean square error, brute force, key sensitivity, and peak signal to noise ratio analyses. The randomness of the ciphers produced by the proposed technique is also passed through NIST-800-22. The results of NIST indicate that the ciphers are highly random and do not produce any type of periodicity or pattern. (shrink)

The study investigated the conduct of university’s congregation election following the general complaints by university staff of poor organization and conduct. The population consisted of all principal officers and all graduates employed by the various universities in the three geo-political zones of Nigerian federation: North-Central, Southeast, and Southwest. From these zones, a sample of two federal and two state universities were selected by stratified random sampling method for the study. A stratified random sampling method was used to select (...) 200 (100 academic and 100 non-academic) staff from each of federal government universities while 100 (50 academic and 50 non-academic) staff was selected from state universities. A total sample of 900 academic staff (450 males and 450 females) and 900 administrative staff (450males and 450 females) participated in the study. The data of the study were collected using questionnaire. The questionnaire was titled Management of Congregation Election Inventory (MCEI). It was made up of two parts – Part A was demographic while Part B contained 12 questions bothering on organization of previous elections, management and outcome of previous election results. The validity of the questionnaire was made by the experts in educational administration and planning and also in political Science. The reliability of the instrument was tested using a Split-Half Method. The Correlation Coefficient was corrected by the use of Spearman Brown Formula. The Pearson Product Moment Correlation was .75 and final Spearman Brown Formula yielded 0.82. The major finding was that election was poorly organized and conducted, Based on the findings, the major recommendation was a surgical change in the organization and conduct of congregation election. (shrink)

Data mining, as an essential part of artificial intelligence, is a powerful digital technology, which makes businesses predict future trends and alleviate the process of decision-making and enhancing customer experience along their digital transformation journey. This research provides a practical implication – a case study - to provide guidance on analyzing information and predicting repairs in home appliances after sales services business. The main benefit of this practical comparative study of various classification algorithms, by using the Weka tool, is the (...) analysis of information and the prediction of repairs in the home appliances after sales services business. The comparison of algorithms is performed considering different parameters, such as the mean absolute error, root mean square error, relative absolute error and root relative squared error, receiver operating characteristic area, accuracy, Matthews’s correlation coefficient, precision-recall curve, precision, F-measure, recall and statistical criteria. Five classification algorithms such as the Naive Bayes, J48, random forest, K-Nearest Neighbor, and logistic regression were implemented in the dataset. J48 has proved to provide the best accuracy and the lowest error among the other examined algorithms applied to a home appliances after sales services dataset to predict repairs based on product guarantee period. The extracted information and results of an after sales services business by using data mining techniques prove to alleviate the process of streamlining decision-making and provide reliable predictions, especially for the customers, as well as increase businesses’ efficiency along their digital transformation journey. (shrink)

BackgroundThere are limited sensitive evaluation methods to distinguish people’s symptoms of peripheral fatigue and central fatigue simultaneously. The purpose of this study is to identify and evaluate them after acute exercise with a simple and practical scale.MethodsThe initial scale was built through a literature review, experts and athlete population survey, and a small sample pre-survey. Randomly selected 1,506 students were evaluated with the initial scale after exercise. Subjective fatigue self-assessments were completed at the same time.ResultsThe Acute Exercise-Induced Fatigue Scale was (...) determined after performing a factor analysis. In the exploratory factor analysis, the cumulative variance contribution rate was 65.464%. The factor loadings of the total 8 questions were 0.661–0.816. In the confirmatory factor analysis, χ2/df = 2.529, GFI = 0.985, AGFI = 0.967, NFI = 0.982, IFI = 0.989, CFI = 0.989, and RMSEA = 0.048. The Cronbach’s alpha coefficient for the scale was 0.872, and it was 0.833 for peripheral fatigue and 0.818 for central fatigue. The intra-class correlation coefficient for the scale was 0.536, and the intra-class correlation coefficients for peripheral fatigue and central fatigue were 0.421 and 0.548, respectively. The correlation coefficient between the total score of the AEIFS and the SFSA score was 0.592.ConclusionOur results demonstrate that the AEIFS can distinguish peripheral fatigue and central fatigue and can also reflect their correlation. This scale can be a useful evaluation tool not only for measuring fatigue after acute exercise but also for guiding reasonable exercise, choosing objective testing indicators, and preventing sports injuries resulting from acute exercise-induced fatigue. (shrink)

Non-commuting quantities and hidden parameters – Wave-corpuscular dualism and hidden parameters – Local or nonlocal hidden parameters – Phase space in quantum mechanics – Weyl, Wigner, and Moyal – Von Neumann’s theorem about the absence of hidden parameters in quantum mechanics and Hermann – Bell’s objection – Quantum-mechanical and mathematical incommeasurability – Kochen – Specker’s idea about their equivalence – The notion of partial algebra – Embeddability of a qubit into a bit – Quantum computer is not Turing machine – (...) Is continuality universal? – Diffeomorphism and velocity – Einstein’s general principle of relativity – „Mach’s principle“ – The Skolemian relativity of the discrete and the continuous – The counterexample in § 6 of their paper – About the classical tautology which is untrue being replaced by the statements about commeasurable quantum-mechanical quantities – Logical hidden parameters – The undecidability of the hypothesis about hidden parameters – Wigner’s work and и Weyl’s previous one – Lie groups, representations, and psi-function – From a qualitative to a quantitative expression of relativity − psi-function, or the discrete by the random – Bartlett’s approach − psi-function as the characteristic function of random quantity – Discrete and/ or continual description – Quantity and its “digitalized projection“ – The idea of „velocity−probability“ – The notion of probability and the light speed postulate – Generalized probability and its physical interpretation – A quantum description of macro-world – The period of the as-sociated de Broglie wave and the length of now – Causality equivalently replaced by chance – The philosophy of quantum information and religion – Einstein’s thesis about “the consubstantiality of inertia ant weight“ – Again about the interpretation of complex velocity – The speed of time – Newton’s law of inertia and Lagrange’s formulation of mechanics – Force and effect – The theory of tachyons and general relativity – Riesz’s representation theorem – The notion of covariant world line – Encoding a world line by psi-function – Spacetime and qubit − psi-function by qubits – About the physical interpretation of both the complex axes of a qubit – The interpretation of the self-adjoint operators components – The world line of an arbitrary quantity – The invariance of the physical laws towards quantum object and apparatus – Hilbert space and that of Minkowski – The relationship between the coefficients of -function and the qubits – World line = psi-function + self-adjoint operator – Reality and description – Does a „curved“ Hilbert space exist? – The axiom of choice, or when is possible a flattening of Hilbert space? – But why not to flatten also pseudo-Riemannian space? – The commutator of conjugate quantities – Relative mass – The strokes of self-movement and its philosophical interpretation – The self-perfection of the universe – The generalization of quantity in quantum physics – An analogy of the Feynman formalism – Feynman and many-world interpretation – The psi-function of various objects – Countable and uncountable basis – Generalized continuum and arithmetization – Field and entanglement – Function as coding – The idea of „curved“ Descartes product – The environment of a function – Another view to the notion of velocity-probability – Reality and description – Hilbert space as a model both of object and description – The notion of holistic logic – Physical quantity as the information about it – Cross-temporal correlations – The forecasting of future – Description in separable and inseparable Hilbert space – „Forces“ or „miracles“ – Velocity or time – The notion of non-finite set – Dasein or Dazeit – The trajectory of the whole – Ontological and onto-theological difference – An analogy of the Feynman and many-world interpretation − psi-function as physical quantity – Things in the world and instances in time – The generation of the physi-cal by mathematical – The generalized notion of observer – Subjective or objective probability – Energy as the change of probability per the unite of time – The generalized principle of least action from a new view-point – The exception of two dimensions and Fermat’s last theorem. (shrink)

The present study investigated estimate biases in cross-classified random effect modeling and hierarchical linear modeling when ignoring a crossed factor in CCREM considering the impact of the feeder and the magnitude of coefficients. There were six simulation factors: the magnitude of coefficient, the correlation between the level 2 residuals, the number of groups, the average number of individuals sampled from each group, the intra-unit correlation coefficient, and the number of feeders. The targeted interests of the coefficients were (...) four fixed effects and two random effects. The results showed that ignoring a crossed factor in cross-classified data causes a parameter bias for the random effects of level 2 predictors and a standard error bias for the fixed effects of intercepts, level 1 predictors, and level 2 predictors. Bayesian information criteria generally outperformed Akaike information criteria in detecting the correct model. (shrink)

Kinetic demixing in quaternary mixed oxides has not been investigated previously, either theoretically or experimentally. In this theoretical study, we derive simple and exact analytical expressions that describe the steady-state cation concentration profiles resulting from kinetic demixing in mixed oxides of the O type. The concentration profiles are expressed in terms of cation-vacancy exchange frequency ratios. We assume a random distribution of cations and make use of the Moleko-Allnatt exact sum-rule expression relating the phenomenological coefficients in the ternary (...) random alloy to the vacancy mechanism operative. We employ Monte Carlo simulation of kinetic demixing to verify the result of the analysis. We discuss how kinetic demixing profiles can be processed to obtain atom-vacancy exchange frequency ratios. We also discuss how atom-vacancy exchange frequencies themselves might be obtained from available diffusivities in the quaternary oxide. (shrink)

ABSTRACT Ethical and political attitudes are not randomly distributed in a population. Attitudes of family members, for example, tend to be more similar than those of a random sample of the same size. In the fields of social psychology and political science, the historically standard explanation for these attitude distribution patterns was that social and political attitudes are a function of environmental factors like parental socialization and prevailing social norms. This received view is, however, complicated by more recent work (...) in behavioral genetics, which consistently and repeatedly demonstrates that certain ethical and political attitudes dealing with issues like censorship, abortion, capital punishment, and immigration policy have a significant heritability coefficient, to wit, a substantial percentage of attitude variance in a population can be attributed to genetic variance, independent of environmental factors. In this paper, I argue that the genetic influence on our ethical and political attitudes is mediated by what we can agree to be irrelevant and distorting factors that can lead moral reasoning astray. Further, I argue that we should significantly lower our credences in ethical and political attitudes that fall within the domains of belief that involve significant genetic influence. (shrink)

In this paper the squared mass of the hadron is defined as a random variable, whose average is the measured quantity. This leads to a mass formula, of a unique type for mesons and baryons, with a general law for the spin variation of the coefficients. The central squared masses form an overall geometrical scheme; in the baryon case it contains trajectories which are a fine structure of the Regge trajectories. For the accurately measured masses the difference between (...) the computed and experimental value lies within 5 MeV for mesons and baryons. The geometrical scheme will be the basis for the computation of the decay rates, to be developed in the next paper. (shrink)

The double empathy problem theory posits that autistic social difficulties emerge from an interpersonal misalignment in social experiences and expectations between autistic and non-autistic people. Supporting this, emerging research reveals better social outcomes in interactions within than across neurotypes among autistic and non-autistic people, emphasizing the need to examine the role of the interpersonal context in autistic social outcomes. However, research on peer relationships among autistic youth primarily focuses on individual characteristics in isolation from the interpersonal context. To address this, (...) this preliminary study explored the effects of student-peer neurotype match on peer relationships among autistic and non-autistic youth in an integrated educational setting. We plotted the peer relationship networks among youth in a school club based on systematic observations of peer interactions over eight 45-min sessions. Descriptive network statistics showed that both autistic and non-autistic youth had more and stronger peer relationships with their same- than cross-neurotype peers. Assortativity coefficients revealed a tendency for youth to connect with peers of the same neurotype, rather than with peers with similar social popularity or activity. We further modeled the effects of student-peer neurotype match on peer relationships using exponential random graph models. The findings suggested that student-peer neurotype match predicted the total strength of peer relationships above and beyond the effects of student neurotype, individual heterogeneity in social popularity and activity, and the tendency of mutuality in social relationships. We discussed the strengths and limitations of this study and the implications for future research and inclusion practice. (shrink)

Background The increasing prevalence of moral distress in the stressful environment of the intensive care unit (ICU) provides grounds for nursing error and endangers patients’ health, safety, and even life. One of the most important reasons for this distress is the treatment team’s second victim syndrome (SVS), especially nurses, following errors in the treatment system. Objectives The present study aimed to determine the relationship between moral distress and SVS in ICUs. Research design This cross-sectional study involved a sample size of (...) 96 ICU nurses working in hospitals affiliated with Tehran University of Medical Sciences, Iran, in the 2021–2022 period, who were selected via a simple random sampling method. Data were collected using the Demographic Questionnaire, the second victim experience and support tool (SVEST) and Moral Distress Scale-Revised (MDS-R). Descriptive statistics (percentage, frequency, mean, and SD) and analytical tests (Spearman correlation coefficient test, independent t-test, and ANOVA) were employed for data analysis. Participants and research context This study used a sample size of 96 intensive care unit nurses working in hospitals affiliated to Tehran University of Medical Sciences selected by simple random sampling. Ethical considerations The study obtained research ethics approval, and all participants were informed of the voluntary and anonymous nature of their participation. Findings The results showed that 59.4% of nurses suffered a low level of moral distress, and 40.6% suffered from a moderate level of moral distress. The SVS score of 86.5% of the nurses was moderate. There was no significant and direct correlation between moral distress and SVS in nurses; however, there was a significant and inverse correlation between the moral distress intensity and SVS ( p = 0.011). Conclusion Despite no significant correlation between moral distress and SVS, these variables were at moderate levels. Accordingly, it is suggested to provide a proper ground for expressing morally stressful situations, counseling and training strategies to deal with moral distress, creating support resources for those suffering from SVS, and implementing empowerment programs. (shrink)

Background: Job satisfaction is largely associated with organizational aspects, including improved working environments, worker’s well-being and more effective performance. There are many definitions regarding job satisfaction in the existing scholarly literature: it can be expressed as a positive emotional state, a positive impact of job-related experiences on individuals, and employees’ perceptions regarding their jobs. Aims: No reliable scales in Arabic language to assess job satisfaction in the sports and physical education field exist.This study aimed to trans-culturally adapt and validate the (...) Pepe’s “Teacher Job Satisfaction Scale” 9 items (TJSS-9), creating the “Teacher of Physical Education Job Satisfaction Inventory” (TPEJSI) in Arabic language. This scale was administered to a Tunisian population of sports and physical education teachers and analyzed according to the Pepe’s theoretical model.. More in detail, this investigation systematically tested its factor structure, in terms of internal consistency/reliability, predictive validity, sensitivity and convergent validity. Methods: A total of 417 Tunisian teachers of sports and physical education participated voluntarily in this study. The sample comprised of 258 males and of 159 females. More in detail, 189 were teachers teaching in primary schools of physical education, 105 teaching in secondary schools, and 123 were university teachers. Both exploratory (EFA) and confirmatory (CFA) factor analyses were performed on random-split halves of the sample. Results: The three-dimensional alpha coefficients of the TPEJSI were all greater than 0.80: for satisfaction with colleagues, alpha was 0.865; for satisfaction with parents, alpha was 0.856 and for satisfaction with students alpha was 0.860. The CFA fit indices were satisfactory. Conclusions: Given the good EFA factor loadings, the CFA fit indices, the correlation matrix, the sensitivity analysis, the convergent validity and the excellent internal consistency, it can be concluded that the TPEJSI is a good psychometric tool that can be used to quantitatively assess the job satisfaction level among teachers of sports and physical education in the Arabic-speaking world. (shrink)

Software defects prediction at the initial period of the software development life cycle remains a critical and important assignment. Defect prediction and correctness leads to the assurance of the quality of software systems and has remained integral to study in the previous years. The quick forecast of imperfect or defective modules in software development can serve the development squad to use the existing assets competently and effectively to provide remarkable software products in a given short timeline. Hitherto, several researchers have (...) industrialized defect prediction models by utilizing statistical and machine learning techniques that are operative and effective approaches to pinpoint the defective modules. Tree family machine learning techniques are well-thought-out to be one of the finest and ordinarily used supervised learning methods. In this study, different tree family machine learning techniques are employed for software defect prediction using ten benchmark datasets. These techniques include Credal Decision Tree, Cost-Sensitive Decision Forest, Decision Stump, Forest by Penalizing Attributes, Hoeffding Tree, Decision Tree, Logistic Model Tree, Random Forest, Random Tree, and REP-Tree. Performance of each technique is evaluated using different measures, i.e., mean absolute error, relative absolute error, root mean squared error, root relative squared error, specificity, precision, recall, F-measure, G-measure, Matthew’s correlation coefficient, and accuracy. The overall outcomes of this paper suggested RF technique by producing best results in terms of reducing error rates as well as increasing accuracy on five datasets, i.e., AR3, PC1, PC2, PC3, and PC4. The average accuracy achieved by RF is 90.2238%. The comprehensive outcomes of this study can be used as a reference point for other researchers. Any assertion concerning the enhancement in prediction through any new model, technique, or framework can be benchmarked and verified. (shrink)

Deterministic models in population dynamics often are really approximations to stochastic models, justified by an appeal to the law of large numbers. It is proposed to call such models pseudodeterministic. Four questions are discussed in this article: (1) What errors may be made by equating deterministically predicted values to expectations? (2) When, and in what sense, may numbers be assumed to be large? (3) How large are the variances, coefficients of variations, etc., as assigned to the variables in the (...) stochastic versions of the models? (4) What role may pseudodeterministic models play in empirical research, where problems of statistical reliability arise?As an example, a modified Nicholson-Bailey model of the interaction between insect parasitoids and their hosts is discussed; the modification consists of assigning a random (density-independent) mortality to the parasitoid population. A stochastic version of this model is discussed. The expectation of the final host density is compared with the value computed from the deterministic model. The latter value is systematically lower than the former. The magnitude of the difference depends on parameter values. The variability to be expected with the stochastic model is characterized by the coefficient of variation of the final host density; its dependence on parameter values and initial conditions is discussed. It is concluded that it is worthwhile in practical applications to estimate parasitoid mortality, and that the coefficient of variation in real situations may be far from negligible. (shrink)

While the control of cell migration by biochemical and biophysical factors is largely documented, a precise quantification of cell migration parameters in different experimental contexts is still questionable. Indeed, these phenomenological parameters can be evaluated from data obtained either at the cell population level or at the individual cell level. However, the range within which both characterizations of cell migration are equivalent remains unclear. We analyse here to which extent both sources of data could be integrated within a unified description (...) of cell migration by considering the motility of the endothelial cell line EAhy926. Using time-lapse video-microscopy and associated analysis of digital image time series, we quantified EAhy926 random motility coefficient, migration speed and trajectory persistence time in two different migration assays: the in vitro wound healing assay, and the cell-populated agarose drop assay. In order to analyse the agreement between independent quantifications of cell motility based either on individual cell analysis or cell population dynamic analysis, a theoretical multi-agents cellular model was developed and discussed as a possible theoretical framework able to unify these multi-scale data. Model simulations especially reveal the potential bias induced by cell proliferation and cell-cell adhesion when cell migration parameters are estimated from the extensively used in vitro wound healing assay. (shrink)

Suicide, as one of the leading causes of death for the adolescent population, both in Chile and globally, remains a complex and elusive phenomenon. This research studies the association between positive and negative affect in relation with suicidal ideation and suicidal attempt, given that affectivity is a fundamental basis on which people make evaluations on their satisfaction with life. First, it examines the reliability, structure, and validity of Watson’s positive and negative affect scale (PANAS) scale in a representative random (...) sample of Chilean high school students (N= 4,568). The scale evidences strong reliability coefficients and a confirmatory factor analysis, excluding one positive (excited) and one negative (nervous) item. The scale shows a satisfactory goodness of fit. Secondly, it investigates the association of PANAS positive and negative affect scores with suicidal ideation as well as reported attempt in adolescents, controlling for the potential effect of age and sex (N= 420 high school students). Low positive and high negative affect, but not sex and age, show a significant association with suicidal ideation. Suicidal ideation totally mediates the association of affect with suicide attempt, as expected. Results are discussed regarding prevention and it considers how positive and negative affect can be relevant as indicators for prevention and treatment using widely available technology. (shrink)