A New Mixture Model With Cure Rate Applied to Breast Cancer Data.

We introduce a new modelling for long-term survival models, assuming that the number of competing causes follows a mixture of Poisson and the Birnbaum-Saunders distribution. In this context, we present some statistical properties of our model and demonstrate that the promotion time model emerges as a limiting case. We delve into detailed discussions of specific models within this class. Notably, we examine the expected number of competing causes, which depends on covariates. This allows for direct modeling of the cure rate as a function of covariates. We present an Expectation-Maximization (EM) algorithm for parameter estimation, to discuss the estimation via maximum likelihood (ML) and provide insights into parameter inference for this model. Additionally, we outline sufficient conditions for ensuring the consistency and asymptotic normal distribution of ML estimators. To evaluate the performance of our estimation method, we conduct a Monte Carlo simulation to provide asymptotic properties and a power study of LR test by contrasting our methodology against the promotion time model. To demonstrate the practical applicability of our model, we apply it to a real medical dataset from a population-based study of incidence of breast cancer in São Paulo, Brazil. Our results illustrate that the proposed model can outperform traditional approaches in terms of model fitting, highlighting its potential utility in real-world scenarios.

Sodium bicarbonate induces alkalosis, but improves high-intensity cycling performance only when participants expect a beneficial effect: a placebo and nocebo study.

The study aimed to investigate the effects of sodium bicarbonate (NaHCO3) intake with divergent verbal and visual information on constant load cycling time-to-task failure, conducted within the severe intensity domain. Fifteen recreational cyclists participated in a randomized double-blind, crossover study, ingesting NaHCO3 or placebo (i.e., dextrose), but with divergent information about its likely influence (i.e., likely to induce ergogenic, inert, or harmful effects). Performance was evaluated using constant load cycling time to task failure trial at 115% of peak power output estimated during a ramp incremental exercise test. Data on blood lactate, blood acid-base balance, muscle electrical activity (EMG) through electromyography signal, and the twitch interpolation technique to assess neuromuscular indices were collected. Despite reduced peak force in the isometric maximal voluntary contraction and post-effort peripheral fatigue in all conditions (P < 0.001), neither time to task failure, EMG nor, blood acid-base balance differed between conditions (P > 0.05). Evaluation of effect sizes of all conditions suggested that informing participants that the supplement would be likely to have a positive effect (NaHCO3/Ergogenic: 0.46; 0.15-0.74; Dextrose/Ergogenic: 0.45; 0.04-0.88) resulted in improved performance compared to control. Thus, NaHCO3 ingestion consistently induced alkalosis, indicating that the physiological conditions to improve performance were present. Despite this, NaHCO3 ingestion did not influence performance or indicators of neuromuscular fatigue. In contrast, effect size estimates indicate that participants performed better when informed that they were ingesting an ergogenic supplement. These findings suggest that the apparently ergogenic effect of NaHCO3 may be due, at least in part, to a placebo effect.

Cure rate models for heterogeneous competing causes.

Cure rate models have been widely studied to analyze time-to-event data with a cured fraction of patients. In this type of model, the number of concurrent causes is assumed to be a random variable. However, in practice, it is natural to admit that the distribution of the number of competing causes is different from individual to individual. Our proposal is to assume that the number of competing causes belongs to a class of a finite mixture of competing causes distributions. We assume the number of malignant cells follow a mixture of two power series distributions and suppose that the time to the event of interest follows a Weibull distribution. We consider the proportion of the cured number of competing causes depending on covariates, allowing direct modeling of the cure rate. The proposed model includes several well-known models as special cases and defines many new special models. An expectation-maximization algorithm is proposed for parameter estimation, where the expectation step involves the computation of the expected number of concurrent causes for each individual. A Monte Carlo simulation is performed to assess the behavior of the estimation method. In order to show the potential for the practice of our model, we apply it to the real medical data set from a population-based study of incident cases of cutaneous melanoma diagnosed in the state of São Paulo, Brazil, illustrating that the model proposed can outperform traditional models in terms of model fitting.

The country-of-origin label impact on intention to consume insect-based food.

The global food consumption scenario and the influence of a country's image on consumer decision-making motivated this research. The global edible insect market is growing, and cultural issues, disgust, and low perception of quality are barriers to consumption. Through an online experiment (n = 194) Brazilian consumers demonstrate that the use of the country-of-origin label (COOL) can result in greater intention and quality expectation regarding a cricket flour. Consumers showed a preference for the flour produced by a positive image country label. Both intention and quality expectation were higher for the cricket flour produced in the United States. Furthermore, the mediation model indicates that quality expectation mediated the effect of COOL on the intention to consume. The results show that even though consumers have created a positive expectation concerning the product, a higher level of neophobia diminished their intention to consume the product and this relates to the aversion and disgust that can exist towards an edible-insect product. The neophobia level can weaken the effect of COOL on intention mediated by quality expectation. The study aimed to contribute to a better understanding of the consumer's perception of an insect-based food and provide insights into variables related to the intention to consume by verifying their contribution to the consumer's behavior.

Voluntary self-initiation of the stimuli onset improves working memory and accelerates visual and attentional processing.

The ability of an organism to voluntarily control the stimuli onset modulates perceptual and attentional functions. Since stimulus encoding is an essential component of working memory (WM), we conjectured that controlling the initiation of the perceptual process would positively modulate WM. To corroborate this proposition, we tested twenty-five healthy subjects in a modified-Sternberg WM task under three stimuli presentation conditions: an automatic presentation of the stimuli, a self-initiated presentation of the stimuli (through a button press), and a self-initiated presentation with random-delay stimuli onset. Concurrently, we recorded the subjects' electroencephalographic signals during WM encoding. We found that the self-initiated condition was associated with better WM accuracy, and earlier latencies of N1, P2 and P3 evoked potential components representing visual, attentional and mental review of the stimuli processes, respectively. Our work demonstrates that self-initiated stimuli enhance WM performance and accelerate early visual and attentional processes deployed during WM encoding. We also found that self-initiated stimuli correlate with an increased attentional state compared to the other two conditions, suggesting a role for temporal stimuli predictability. Our study remarks on the relevance of self-control of the stimuli onset in sensory, attentional and memory updating processing for WM.

Relacionamentos amorosos na contemporaneidade: um estudo exploratório sobre expectativas e experiências das mulheres / Loving relationships: an exploratory research on the expectations and life experiences of women / Relaciones amorosas contemporáneas: un estudio exploratorio sobre las expectativas y experiencias de las mujeres

O presente artigo apresenta os resultados parciais de pesquisa realizada com 2778 mulheres, intitulada "Relacionamentos amorosos na contempo-raneidade: quais as expectativas das mulheres?" (Millan et al., 2019), que visou à compreensão das relações afetivo-sexuais na contemporaneidade a partir da visão das mulheres e o conhecimento da dinâmica das relações com seus pares, com vistas ao manejo de conflitos nos relacionamentos afetivos e familiares, em intervenções clínicas e sociais. Teve-se como objetivo destacar aspectos relativos às diferenças entre expectativas e experiências vividas nos relacionamentos, no que diz respeito aos papéis de gênero (desempenho das tarefas domésticas e cuidados com filhos), à vida profissional, à independência financeira, aos sonhos e projetos de vida. A metodologia utilizada foi de carac-terística quantitativa e qualitativa, com as respostas ao questionário tratadas como variáveis qualitativas ordinais e analisadas pelos testes estatísticos não paramétricos de Kruskal-Wallis ou de Mann-Whitney (1952), de acordo com o agrupamento das participantes, quanto à faixa etária, escolaridade e estado civil. As variáveis categóricas foram analisadas pelo Teste de Qui-quadrado ou pelo Teste Exato de Fisher, conforme a indicação. Na análise qualitativa, adotaram-se os referenciais psicanalítico e sistêmico. Os resultados obtidos mostram que as expectativas das mulheres nos relacionamentos amorosos são moduladas pela experiência vivida e passíveis de ajustes e reajustes durante o ciclo vital pessoal e familiar. As variáveis independentes (escolaridade, estado civil, faixa etária) influenciaram significativamente e de maneiras distintas as respostas analisadas neste artigo. Conclui-se que os relacionamentos amorosos expressam elementos próprios da contemporaneidade, na qual convivem tendências variadas de valores, condutas e pontos de vista dissonantes, em constante transformação.

This article reports partial results of the research "Loving relationships in contemporary times: what are women's expectations?" (Millan et al., 2019) carried out with 2,778 women, that aimed to comprehend affective-sexual rela-tionships in the contemporary era, from women's point of view and knowledge of the dynamics in their relationships with their peers, in order to develop clinical tools to manage conflicts in affective and familiar relationships, via clinical and social interventions. Its objective is to highlight aspects concerning differences between expectations and experiences in relationships, regarding gender roles (in the performance of household tasks and childcare), profes-sional life, financial independence, life dreams and projects. Quantitative and qualitative data were obtained, while answers to the questionnaire were labeled as qualitative ordinal variables and analyzed through Kruskal-Wallis or Mann-Whitney (1952) nonparametric statistical tests, according to the grouping of participants, by age, education and marital status. Categorical variables were analyzed through a Chi-squared Test or Fisher's exact test, as appropriate. In the qualitative analysis, psychoanalytic and systemic refe-rences were adopted. The obtained results show that women's expectations towards loving relationships are influenced by life experiences and prone to change throughout personal and familiar life cycles. The independent varia-bles (education, age, marital status) have significantly influenced the results in different ways. It is concluded that loving relationships express elements characteristic of contemporaneity, which presents several tendencies, diverse in values, conducts and dissonant points of view, in constant transformation.

Este artículo presenta los resultados parciales de una investigación realizada con una muestra de 2.778 mujeres, denominada "Relaciones amorosas en la actualidad: ¿cuáles son las expectativas de las mujeres?" (Millan et al., 2019), que tuvo como objetivo comprender las relaciones afectivo-sexuales en la contemporaneidad desde la perspectiva de las mujeres y el conocimiento de la dinámica de las relaciones con sus pares, con miras a gestionar los conflictos en las relaciones afectivas y familiares en intervenciones clínicas y sociales. El objetivo fue resaltar aspectos relacionados con las diferencias entre expec-tativas y experiencias vividas en las relaciones, en cuanto a roles de género (desempeño de las tareas del hogar y cuidado de los niños), vida profesional, independencia económica, sueños y proyectos de vida. La metodología utilizada fue cuantitativa y cualitativa, con las respuestas a las entrevistas tratadas como variables cualitativas ordinales y analizadas mediante las pruebas estadísticas no paramétricas de Kruskal-Wallis o Mann-Whitney (1952), agrupando las participantes en función del grupo etario, nivel de educación y estado civil. Las variables categóricas se analizaron mediante la prueba de Chi-cuadrado o la prueba exacta de Fisher, según se indica en cada caso. En el análisis cualitativo se adoptaron referencias psicoanalíticas y sistémicas. Los resultados obtenidos muestran que las expectativas de las mujeres en las relaciones amorosas están moduladas por la experiencia vivida y están sujetas a ajustes y reajustes durante el ciclo de vida personal y familiar. Las variables independientes (nivel de educación, estado civil, grupo etario) influyeron significativamente de diferentes formas en las respuestas analizadas en este artículo. Se concluye que las relaciones amorosas expresan elementos de contemporaneidad en los que conviven diferentes tendencias de valores, comportamientos y puntos de vista disonantes en constante transformación.

Priming overconfidence in belief systems reveals negative return on postural control mechanisms.

BACKGROUND: Modulation of postural control strategies and heightened perceptual ratings of instability when exposed to postural threats, illustrates the association between anxiety and postural control. RESEARCH QUESTION: Here we test whether modulating prior expectations can engender postural-related anxiety which, in turn, may impair postural control and dissociate the well-established relationship between sway and subjective instability. METHODS: We modulated expectations of the difficulty posed by an upcoming postural task via priming. In the visual priming condition, participants watched a video of an actor performing the task with either a stable or unstable performance, before themselves proceeding with the postural task. In the verbal priming paradigm, participants were given erroneous verbal information regarding the amplitude of the forthcoming platform movement, or no prior information. RESULTS: Following the visual priming, the normal relationship between trunk sway and subjective instability was preserved only in those individuals that viewed the stable but not the unstable actor. In the verbal priming experiment we observed an increase in subjective instability and anxiety during task performance in individuals who were erroneously primed that sled amplitude would increase, when in fact it did not. SIGNIFICANCE: Our findings show that people's subjective experiences of instability and anxiety during a balancing task are powerfully modulated by priming. The contextual provision of erroneous cognitive priors dissociates the normally 'hard wired' relationship between objective measures and subjective ratings of sway. Our findings have potential clinical significance for the development of enhanced cognitive retraining in patients with balance disorders, e.g. via modifying expectations.

Do the Colors of the Label and the Sweetening Agent Information Influence the Sensory Expectations Consumer? A Case Study with Skyr-Type Yogurt.

The objective of this research was to evaluate the sensory expectation and buying intention of consumers from different Brazilian regions for skyr-type yogurt based on the colors and sweetener on its label. Ten images of skyr mango yogurt labels were created varying in color (orange, white, yellow, blue, and green) and sweetening agent (sucrose and natural sweeteners). Consumers (151 consumers) were asked to rate their expectation for the ideal of sweetness, healthiness, acceptance, and buying intention. Labels containing the information "sweetened with sucrose" had a higher percentage of expectation of sweeter than ideal. Label color and sweetening agent had a significant effect on the expectation of acceptance, with a higher percentage for yogurt sweetened with natural sweeteners. There were not statistical differences (p > 0.05) between the labels regarding expected healthiness. Results also showed that consumers had a low level of familiarity with skyr-type yogurts, but it is presented as a healthy yogurt alternative.

Prior Distribution and Entropy in Computer Adaptive Testing Ability Estimation through MAP or EAP.

To derive a latent trait (for instance ability) in a computer adaptive testing (CAT) framework, the obtained results from a model must have a direct relationship to the examinees' response to a set of items presented. The set of items is previously calibrated to decide which item to present to the examinee in the next evaluation question. Some useful models are more naturally based on conditional probability in order to involve previously obtained hits/misses. In this paper, we integrate an experimental part, obtaining the information related to the examinee's academic performance, with a theoretical contribution of maximum entropy. Some academic performance index functions are built to support the experimental part and then explain under what conditions one can use constrained prior distributions. Additionally, we highlight that heuristic prior distributions might not properly work in all likely cases, and when to use personalized prior distributions instead. Finally, the inclusion of the performance index functions, arising from current experimental studies and historical records, are integrated into a theoretical part based on entropy maximization and its relationship with a CAT process.

Quality of care in the EsSalud emergency service, northern Region, Peru.

This study explores the user's quality of medical attention. The aim was to analyze the quality-of-care indicators in the EsSalud emergency service of the hospitals of the Lambayeque Juan Aita Valle Healthcare Network, according to the perceptions and expectations of the patients. The research has a descriptive, correlational, cross-sectional design, which includes the description, registration, analysis, and interpretation of the current nature of the quality of emergency medical care in the selected hospital institutions. The population is represented by patients who attended the emergency department of the hospital institution's understudy for one month. The sample was obtained using a simple random system. The technique used was the application of Servqual Quality of Emergency Care questionnaire. The instrument consisted of three parts, General Data, Expectations of the External User, and Perceptions of the External User. All statistical tests were processed using SPSS v.25 through the T-test of means. Higher customer dissatisfaction was revealed with regard to intangibility, lack of security, lack of reliability, and lack of empathy towards the user. User expectations and perceptions regarding the health service quality are also marked by dissatisfaction and great dissatisfaction.

Modelos de medición de la calidad de atención en salud / Health care quality measurement models

Una aproximación para medir el nivel de atención expresada en la calidad de servicio que se presta al paciente en los establecimientos de salud está referida al uso de modelos de medición, que en este artículo se describen desde la propuesta por Donabedian basado en la teoría general de sistemas evaluando estructura, proceso y resultado, pasando a segundo plano la percepción del paciente. Este modelo contrasta con el modelo Nórdico que enfatiza la imagen corporativa, con un balance entre el servicio esperado y la percepción del servicio, basado en el paradigma de la desconfirmación al igual que el modelo presentado por Nguyen. En esta última línea paradigmática se encuentra el modelo más notorio, SERVQUAL que contrasta las expectativas y la precepción del usuario de un servicio identificando brechas en base a las 5 dimensiones propuestas fiabilidad, seguridad, elementos tangibles, capacidad de respuesta, y la empatía, posteriormente basado en este modelo se propone el modelo SERVPERF, basada exclusivamente en la valoración de las percepciones. Posteriormente, se describen el modelo de Desempeño Evaluado que surge como un modelo alternativo al SERVQUAL sustituyendo las expectativas por el concepto de punto ideal; el Modelo Jerárquico Multidimensional que desarrolla una solución tridimensional para completar la modelización de la calidad de servicio. De igual manera el modelo multietapa de valoraciones de la calidad que identifica la disconformidad que existe las expectativas del cliente en relación al servicio y las percepciones de las características por niveles de componente

One approach to measuring the level of care expressed in the quality of service provided to the patient in health facilities is referred to as the use of measurement models described in this paperstarting with the one proposed by Donabedian based on the general theory of systems evaluating structure, process and outcome, with the patient's perception taking second place. In contrast, the Nordic model emphasizes the corporate image, with a balance between the expected service and the perception of the service, based on the paradigm of disconfirmation as well as the model presented by Nguyen. In this paradigmatic line the most notorious model, SERVQUAL, contrasts the expectations and the user's perception of a service identifying gaps based on the 5 proposed dimensions reliability, security, tangible elements, responsiveness, and empathy, later based on this model the SERVPERF model is proposed, based exclusively on the valuation of perceptions. In addition, the Evaluated Performance model, which emerges as an alternative model to SERVQUAL, replaces expectations with the concept of ideal point. And the Multidimensional Hierarchical Model develops a three-dimensional solution to complete the modeling of service quality, as well as the multi-stage model of quality assessments that identifies the non-conformity that exists between customer expectations in relation to the service and the perceptions of the characteristics by component levels

Expectativas de la gestante sobre el acompañamiento de la pareja durante el trabajo de parto

RESUMEN Introducción: El acompañamiento en el parto representa una estrategia con diversos beneficios, por lo cual es necesario comprender las necesidades físicas y emocionales presentes en la mujer para prestar un servicio humanizado y de calidad, que satisfaga sus expectativas. Objetivo: Describir las expectativas de la gestante sobre el acompañamiento de la pareja durante el trabajo de parto en un hospital del tercer nivel de atención. Métodos: Estudio descriptivo y transversal, realizado en 120 gestantes atendidas en el Hospital Nacional "Sergio E. Bernales", que fueron seleccionadas de manera no probabilística. Se aplicó un cuestionario validado sobre la expectativa del acompañamiento de la pareja. Se estimaron frecuencias absolutas y relativas. Resultados: El 98,3 % prefería estar acompañada por su pareja en el parto. En los preparativos para el parto, 75 % prefería que su pareja se informe sobre su rol y 76,7 % que le brinde seguridad y confianza. Para el periodo de dilatación, 88,3 % esperaba que su pareja la comprenda y 6,7 % señaló que no quisiera recibir masajes por parte de su pareja. Para el periodo expulsivo, 96,7 % señaló que esperaba que su pareja esté atento al nacimiento del bebé; y para el alumbramiento, 95 % esperaba que su pareja muestre afecto a su hijo. Conclusiones: Las gestantes presentan altas expectativas sobre el acompañamiento previo y durante el proceso de trabajo de parto, especialmente en el aspecto emocional con ella y el recién nacido.

ABSTRACT Introduction: Accompaniment in childbirth represents a strategy with various benefits, which is why it is necessary to satisfy the physical and emotional needs present in women to provide a humanized and quality service that satisfies their expectations. Objective: To describe the expectations of the pregnant woman about the accompaniment of the couple during labor in a hospital of the tertiary care level. Methods: Descriptive and cross-sectional study, carried out in 120 pregnant women treated at the Sergio E. Bernales National Hospital, who were selected in a non-probabilistic way. A validated questionnaire was applied on the expectation of the accompaniment of the couple. Absolute and relative frequencies were estimated. Results: The 98,3 % preferred to be accompanied by their partner during childbirth. In preparing for childbirth, 75 % preferred that their partner be informed about her role and 76.7 % that they provide security and confidence. For the period of dilation, 88,3 % expected their partner to understand and 6,7 % indicated that they did not want to receive messages from their partner. For the second stage, 96,7 % indicated that they expected their partner to be attentive to the birth of the baby; and for delivery, 95 % expected their partner to show affection to their child. Conclusions: Pregnant women have high expectations about the accompaniment before and during the labor process, especially in the emotional aspect with her and the newborn.

Toward Healthier Cookie Habits: Assessing the Role of Packaging Visual Appearance in the Expectations for Dietary Cookies in Digital Environments.

As we tend to consume more and more via e-commerce platforms, the digital version of a dietary product's package can be one of the most important touchpoints that the consumer has with such product during the purchasing stage of the consumer's journey. Hence, a dietary food/drink properly presented via its packaging in e-commerce is key, for example, to nudge consumers toward healthier purchase habits. In this study, we assessed the role of different configurations of visual cues commonly present in a product's packaging (jar vs. bag, transparent vs. opaque, labeled vs. unlabeled) in the expectations associated with dietary cookies when presented in a digital environment. A between-participants study was conducted where eight different packages with different combinations of the three aforementioned features were digitally evaluated by the participants. The results suggest that the presence (vs. absence) of labeling triggered the highest ratings on most assessed dimensions (product quality, healthiness, lightness, sweetness, crumbliness, price, tastiness, greediness for product, product/packaging liking). Moreover, transparent (vs. opaque) packaging tends to yield higher expectations concerning this product's quality (i.e., product liking, package liking, greediness), though it has an opposite effect on the expected healthiness for such cookies. Some particular interactions between these three visual cues were also observed and are discussed as part of the obtained results. In summary, our results point to how the visual appearance of packaging can be strategically used in order to potentially nudge consumers toward healthier cookie purchase habits.

Empirical assumptions behind the violation of expectation experiments in human and non-human animals.

One of the most widely used procedures applied to non-human animals or pre-linguistic humans is the "violation of expectation paradigm". Curiously there is almost no discussion in the philosophical literature about it. Our objective will be to provide a first approach to the meta-theoretical nature of the assumptions behind the procedure that appeals to the violation of expectation and to extract some consequences. We show that behind them exists an empirical principle that affirms that the violation of the expectation of certain mental rules generates surprise. We then proceeded to discuss the nature of these "mental rules". We show that, as is often the case with theoretical concepts proposed by theories, they do not have a fixed interpretation. This will allow us to show that the usual relationship found in the developmental psychology literature between this experimental paradigm and cognitive approaches (which interpret experimental results in terms of higher-level mental activities) is not necessary. Finally, we relate this experimental design with the mark test and the inequity aversion test and discuss the possible ampliation of the application of the empirical principle of violation of expectation.

On the Uncertainty Identification for Linear Dynamic Systems Using Stochastic Embedding Approach with Gaussian Mixture Models.

In control and monitoring of manufacturing processes, it is key to understand model uncertainty in order to achieve the required levels of consistency, quality, and economy, among others. In aerospace applications, models need to be very precise and able to describe the entire dynamics of an aircraft. In addition, the complexity of modern real systems has turned deterministic models impractical, since they cannot adequately represent the behavior of disturbances in sensors and actuators, and tool and machine wear, to name a few. Thus, it is necessary to deal with model uncertainties in the dynamics of the plant by incorporating a stochastic behavior. These uncertainties could also affect the effectiveness of fault diagnosis methodologies used to increment the safety and reliability in real-world systems. Determining suitable dynamic system models of real processes is essential to obtain effective process control strategies and accurate fault detection and diagnosis methodologies that deliver good performance. In this paper, a maximum likelihood estimation algorithm for the uncertainty modeling in linear dynamic systems is developed utilizing a stochastic embedding approach. In this approach, system uncertainties are accounted for as a stochastic error term in a transfer function. In this paper, we model the error-model probability density function as a finite Gaussian mixture model. For the estimation of the nominal model and the probability density function of the parameters of the error-model, we develop an iterative algorithm based on the Expectation-Maximization algorithm using the data from independent experiments. The benefits of our proposal are illustrated via numerical simulations.

Solution strategy based on Gaussian mixture models and dispersion reduction for the capacitated centered clustering problem.

The Capacitated Centered Clustering Problem (CCCP)-a multi-facility location model-is very important within the logistics and supply chain management fields due to its impact on industrial transportation and distribution. However, solving the CCCP is a challenging task due to its computational complexity. In this work, a strategy based on Gaussian mixture models (GMMs) and dispersion reduction is presented to obtain the most likely locations of facilities for sets of client points considering their distribution patterns. Experiments performed on large CCCP instances, and considering updated best-known solutions, led to estimate the performance of the GMMs approach, termed as Dispersion Reduction GMMs, with a mean error gap smaller than 2.6%. This result is more competitive when compared to Variable Neighborhood Search, Simulated Annealing, Genetic Algorithm and CKMeans and faster to achieve when compared to the best-known solutions obtained by Tabu-Search and Clustering Search.

An approach to model clustered survival data with dependent censoring.

In this study we introduce a likelihood-based method, via the Weibull and piecewise exponential distributions, capable of accommodating the dependence between failure and censoring times. The methodology is developed for the analysis of clustered survival data and it assumes that failure and censoring times are mutually independent conditional on a latent frailty. The dependent censoring mechanism is accounted through the frailty effect and this is accomplished by means of a key parameter accommodating the correlation between failure and censored observations. The full specification of the likelihood in our work simplifies the inference procedures with respect to Huang and Wolfe since it reduces the computation burden of working with the profile likelihood. In addition, the assumptions made for the baseline distributions lead to models with continuous survival functions. In order to carry out inferences, we devise a Monte Carlo EM algorithm. The performance of the proposed models is investigated through a simulation study. Finally, we explore a real application involving patients from the Dialysis Outcomes and Practice Patterns Study observed between 1996 and 2015.

On the use of the modified power series family of distributions in a cure rate model context.

In this paper, we propose a generalization of the power series cure rate model for the number of competing causes related to the occurrence of the event of interest. The model includes distributions not yet used in the cure rate models context, such as the Borel, Haight and Restricted Generalized Poisson distributions. The model is conveniently parameterized in terms of the cure rate. Maximum likelihood estimation based on the Expectation Maximization algorithm is discussed. A simulation study designed to assess some properties of the estimators is carried out, showing the good performance of the proposed estimation procedure in finite samples. Finally, an application to a bone marrow transplant data set is presented.

External validation of the unified model of information systems continuance (UMISC): An international comparison.

CONTEXT: The Unified Model of Information Systems Continuance (UMISC) is a metamodel for the evaluation of clinical information systems (CISs) that integrates constructs from five models that have previously been published in the literature. UMISC was developed at the Georges Pompidou University Hospital (HEGP) in Paris and was partially validated at the Saint Joseph Hospital Group (HPSJ), another acute care institution using the same CIS as HEGP. OBJECTIVE: The aim of this replication study was twofold: (1) to perform an external validation of UMISC in two different hospitals and country contexts: the Italian Hospital of Buenos Aires (HIBA) in Argentina and the Hospital Sirio Libanes in Sao Paulo, Brazil (HSL); (2) to compare, using the same evaluation model, the determinants of satisfaction, use, and continuance intention observed at HIBA and HSL with those previously observed at HEGP and HPSJ. METHODS: The UMISC evaluation questionnaires were translated from their original languages (English and French) to Brazilian Portuguese and Spanish following the translation/back-translation method. These questionnaires were then applied at each target site. The 21 UMISC-associated hypotheses were tested using structural equation modeling (SEM). RESULTS: A total of 3020 users, 1079 at HIBA and 1941 at the HSL, were included in the analysis. The respondents included 1406 medical staff and 1001 nursing staff. The average profession-adjusted use, overall satisfaction and continuance intention were significantly higher at HIBA than at HSL in the medical and nursing groups. In SEM analysis, UMISC explained 23% and 11% of the CIS use dimension, 72% and 85% of health professionals' satisfaction, and 41% and 60% of continuance intention at HIBA and HSL, respectively. Twenty of the 21 UMISC-related hypotheses were validated in at least one of the four evaluation sites, and 16 were validated in two or more sites. CONCLUSION: The UMISC evaluation metamodel appears to be a robust comparison and explanatory model of satisfaction, use and continuance intention for CISs in late post adoption situations.

Expectation of reward differentially modulates executive inhibition.

BACKGROUND: Inhibitory control, a key modulatory component of cognition guiding strategy and behaviour, can be affected by diverse contingencies. We explore here the effect of expectation of reward over behavioural adjustment in a Stop Signal Task modulated by reward. We hypothesize that cognitive control is modulated by different expectation of the reward. METHODS: Participants were allocated to two groups differing in their degree of knowledge in what to expect from rewards. Expected Specific Reward participants (N = 21) were informed of the different monetary feedbacks they would receive after each successful inhibition. Unexpected Reward participants (N = 24) were only told that they would receive monetary reward after correct inhibitory trials, but not the amounts or differences. RESULTS: Our results confirmed previous observations demonstrating a "kick-start effect" where a high reward feedback at the beginning of the task increases response inhibition. The Expected Specific Reward condition seems also to improve inhibitory control -as measured by the stop signal reaction time (SSRT)-, compared to the Unexpected Reward group. CONCLUSIONS: Knowledge of reward magnitudes seems to play a role in cognitive control irrespective of feedback magnitude. The manipulation of reward expectation appears to trigger different strategies for cognitive control, inducing a bottom-up effect of external cues, or a top-down effect given by the anticipation of incoming rewards. This is an early exploration to unearth possible higher order modulators - expectation and motivation- of cognitive control. This approach aims to gain insight into diverse psychopathological conditions related to impulsivity and altered reward systems such as Attention Deficit Hyperactive Disorder (ADHD), personality disorders, substance abuse, pathological gambling and cognitive aspects of Parkinson Disease.