Search results for "Statistica"
showing 10 items of 5969 documents
Robustness of asymmetry and coherence of quantum states
2016
Quantum states may exhibit asymmetry with respect to the action of a given group. Such an asymmetry of states can be considered as a resource in applications such as quantum metrology, and it is a concept that encompasses quantum coherence as a special case. We introduce explicitly and study the robustness of asymmetry, a quantifier of asymmetry of states that we prove to have many attractive properties, including efficient numerical computability via semidefinite programming, and an operational interpretation in a channel discrimination context. We also introduce the notion of asymmetry witnesses, whose measurement in a laboratory detects the presence of asymmetry. We prove that properly c…
Analysis of a viscoelastic phase separation model
2020
A new model for viscoelastic phase separation is proposed, based on a systematically derived conservative two-fluid model. Dissipative effects are included by phenomenological viscoelastic terms. By construction, the model is consistent with the second law of thermodynamics, and we study well-posedness of the model, i.e., existence of weak solutions, a weak-strong uniqueness principle, and stability with respect to perturbations, which are proven by means of relative energy estimates. A good qualitative agreement with mesoscopic simulations is observed in numerical tests.
Persistent joblessness and fertility intentions
2019
Background: The vast majority of demographic studies have approached and operationalised the notion of economic uncertainty using snapshot indicators. Hence, the complexity and diversity of individuals' employment careers were largely hidden. We posit that the persistence of joblessness - that is, repeated and close spells of joblessness - represents a crucial marker of economic uncertainty in the realm of fertility (intention) research. Objective: We aim to explore the association between persistent joblessness of both members of the couple and women's fertility intentions among those who entered employment at least once in the last five years. Methods: We develop an index of persistent jo…
An operatorial approach to stock markets
2009
We propose and discuss some toy models of stock markets using the same operatorial approach adopted in quantum mechanics. Our models are suggested by the discrete nature of the number of shares and of the cash which are exchanged in a real market, and by the existence of conserved quantities, like the total number of shares or some linear combination of cash and shares. The same framework as the one used in the description of a gas of interacting bosons is adopted.
Comorbid Fluency Difficulties in Reading and Math: Longitudinal Stability Across Early Grades
2018
We examined the prevalence of comorbidity of dysfluent reading and math skills longitudinally in a representative sample ( N = 1,928) and the stability of comorbid and single difficulties from first to fourth grades. The findings indicated that half the children who showed very low performance in one skill also evidenced low or very low performance in the other. Comorbid difficulties had somewhat higher prevalence in third and fourth graders than in first and second graders. The stability of comorbid difficulties was found to be established from Grade 2 onward, but the stability of single difficulties increased steadily across grades. Overall, the findings emphasize the relatively strong s…
Persistent traffic offenders. Alcohol consumption and personality as predictors of driving disqualification
2019
espanolLa seguridad vial es un importante problema social. Muchos accidentes se deben al incumplimiento de las normas de trafico. Las infracciones graves o reiteradas se sancionan por la via administrativa o judicial y en ambos casos las sanciones pueden suponer la perdida del permiso de conducir. Este articulo explora la relevancia del alcohol y la personalidad como factores predictivos. El objetivo del estudio es determinar si el comportamiento delictivo de los infractores persistentes esta relacionado con sus caracteristicas de personalidad y patrones de consumo de alcohol. Se utilizo una muestra de 358 conductores: 232 infractores persistentes, a los que les habia sido retirado el carne…
Job Satisfaction of Fitness Professionals in Portugal: A Comparative Study of Gender, Age, Professional Experience, Professional Title, and Education…
2021
This research characterizes and compares the job satisfaction of fitness professionals in Portugal between genders, ages, professional experience, professional title, and educational qualifications. A total of 401 fitness professionals answered the online questionnaire Job Satisfaction Scale, which has 16 factors rated on a Likert scale with seven levels. The statistical analysis comprises descriptive and statistical tests to compare the results of two (t-test) or more (ANOVA) groups. Overall, the results demonstrated that fitness professionals were moderately satisfied with their work. The lower degrees of job satisfaction were concerning salary, opportunities for promotion, and stability …
Insights into the derivative-based method for nonlinear mediation models
2022
Associational mediation analysis has generally relied on the linearity of models to estimate the indirect effect as a product of regression coefficients. Very few examples of generalisations to nonlinear settings have been proposed, including a derivative-based method that, however, is far from being widely spread among scholars. In this paper, we clarify some aspects of such an approach to nonlinear mediation models, which have not been addressed by the previous literature. In addition, we run a simulation study to compare confidence intervals for the indirect effect obtained through different approaches.
Data from: Can we rely on selected genetic markers for population identification? evidence from coastal Atlantic cod
2019
The use of genetic markers under putative selection in population studies carries the potential for erroneous identification of populations and misassignment of individuals to population of origin. Selected markers are nevertheless attractive, especially in marine organisms that are characterized by weak population structure at neutral loci. Highly fecund species may tolerate the cost of strong selective mortality during early life stages, potentially leading to a shift in offspring genotypes away from the parental proportions. In Atlantic cod, recent genetic studies have uncovered different genotype clusters apparently representing phenotypically cryptic populations that coexist in coastal…
HEMATOLOGICAL VARIABILITY ANALYSIS AFTER ROAD MARATHON VS ULTRATRAIL. PREDICTIVE FACTORS
2020
The practice of long- and medium-distance races has exponentially increased the number of participants in recent years. They are carried out under extreme conditions that cause both biochemical and anthropometric changes in athletes and, in addition, have serious risks associated, such as dehydration, thermal disorders, or hypoglycemia. Knowledge regarding alterations at hematological level after this type of effort is limited. The objectives of this pre-post analytical descriptive observational study were: to describe and compare hematological values in amateur runners pre and post road marathon and ultratrail races, and to compare the hematological parameters between the groups in the two…