Study Of Trajectories Research Articles

Voltaire quadratic stochastic operators of a bisexual population

This article discusses the Voltaire quadratic stochastic operators of the bisexual population and proves it with examples. The concept of a quadratic stochastic operator was first given in the work of S.N. Bernstein [1], devoted to the solution of a mathematical problem related to the theory of heredity. Quadratic operators as an object of research appeared at the turn of the thirties in the works of Ulam [2], where the task was to study the behavior of the trajectories of quadratic operators. The impossibility of creating sufficiently developed analytical methods due to complex and inconvenient iterations in the study of trajectories, and the need for a large number of calculations in the study of exact quadratic operators, did not arouse interest in this problem. The creation of a computer in the forties revived interest in the problem of studying the behavior of the trajectories of quadratic operators. Ulam and his collaborators performed computer calculations for a sufficiently large number of quadratic operators.

Theory of mind in context: Mental-state representations for social evaluation.

Whereas Phillips and colleagues argue that knowledge representations are more basic than belief representations, we argue that an accurate analysis of what is fundamental to theory of mind may depend crucially on the context in which mental-state reasoning occurs. Specifically, we call for increased study of the developmental trajectory of mental-state reasoning within socially evaluative contexts.

Study of the development trajectory of the status indicator in employment in the context of digital transformation

Changes in employment status and rising unemployment are global and driven by rapid technological progress. The coronavirus pandemic also played a huge role, increasing the unemployment rate by 2-4% in different economies. The most declining industries are arts, culture and recreation; spheres of education, law and social, communal and state services; trade. Today, the fragmentation of employment up to self-employment and the spread of various forms of precarious work are clearly visible, and there is an inverse relationship between the share of self-employed workers and the GDP of their countries: in 2018, Burundi had the highest level of self-employment in the world - almost 95%. Arab countries posted the lowest self-employment rates at 1.7%. The emergence of new professions and employment profiles opens up a number of opportunities for the unemployed and the self-employed.

Young people between uncertainty and agency. An analysis of the strategies of transition to adulthood in Italy

The article presents some of the first results obtained during a qualitative longitudinal research on being young in Italy, begun in 2019, promoted by the Department of Sociology and Social Research of the University of Milano-Bicocca. The paper aims at contributing to the study of the life trajectories of young men and women as they deal with a transition to adulthood that appears suspended, especially in relation to the economic, social and cultural fractures determined by the effects of the Covid-19 pandemic. By focusing on life experiences and life courses in Italy, the paper analyses how transition is strongly affected by the geographical, cultural, social and economic contexts in which the biographies of the young people interviewed are immersed. Furthemore, the article explores the subjective meanings they ascribe to those contexts. Firstly, the results show that a common feature of the biographies of the young people we encountered is a perception of uncertainty. More specifically, the paper underlines the ambivalent role that geographical context plays in the narrations and biographies of young people. Especially, when it is characterized by scarcity of resources, and therefore, by the impossibility of recognition and realization of personal aspirations. Lastly, the research shows that the sanitary emergency, with the subsequent containment policies, represents a sudden event that amplifies pre-existing conditions, characteristics, and differences, but at the same time, it triggers novel transformations, at a collective as well as individual level. © 2021, Padova University Press. All rights reserved.

The Future of Obsessive-Compulsive Spectrum Disorders: A Research Perspective.

Obsessive-compulsive disorder (OCD) sits at the epicenter of a spectrum of related conditions (often referred to as obsessive-compulsive related disorders (OCRD) or obsessive-compulsive spectrum disorders (OCSD)) that can be as disabling as they are varied in presentation. Research in the field now encompasses diverse disciplines ranging from inflammatory mechanisms to computational psychiatry, to neurocognitive endophenotypes to functional imaging to pharmacogenomics to brain stimulation approaches. As these disorders become more clearly elucidated, there is a need to continually re-evaluate the implications of research findings and to incorporate these findings into new treatment approaches that benefit both patients and clinicians. Even the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) is intended to be flexible and to incorporate validated and reliable biomarkers and neuroscience findings as they become available. This concluding chapter highlights just a few areas of study that promise to influence our understanding of the pathophysiology and clinical practice of OCRD. These include patient-centered outcomes research, the study of developmental brain trajectories in spectrum conditions, robot models of OCRDs, goal-directed versus habit-based behaviors, pharmacogenomics, problematic use of the Internet, and digital interventions. For example, digital medicine may become increasingly useful by identifying patients early on in the course of their illness; providing biomarkers to subtype patients; predicting treatment response; serving as a more proximal outcome measure of treatment response; or providing easily accessible and less costly forms of care. In order to address unmet clinical needs in OCRD, it is helpful to take an interdisciplinary perspective, and the work described in this collection of articles is likely to be invaluable in shaping the future of the field.

Health care expenditure in the last five years of life is driven by morbidity, not age: A national study of spending trajectories in Danish decedents over age 65.

The high level of medical spending at the end of life is well-documented, but whether there is any real potential for cost reductions there is still in question, and studies have tended to overlook the costs of care. To identify the most common health care spending trajectories over the last five years of life among older Danes, as well as the determinants of following a given trajectory. We linked Danish health registries to obtain data on all health care expenditure (including hospital treatment, prescription drugs, primary care and costs of communal care) over the last five years of life for all Danish decedents above age 65 in the period 2013 through 2017. A latent class analysis identified the most common cost trajectories, which were then related to socio-economical characteristics and health status at five years before death. Total health care expenditures in the last five years of life were largely independent of age and cause of death. Costs of home care and residential care increased steeply with age at death whereas hospital costs decreased correspondingly. We found four main spending trajectories among decedents: 3 percent followed a late-rise trajectory, 11 percent had accelerating costs, and two groups of 43 percent each followed moderately or consistently high trajectories. The main predictor of total expenditure was the number of chronic diseases. Spending at the end of life is largely determined by chronic disease, and age and cause of death only determine the distribution of expenses into care and cure.

Social assistance dynamics in Norway revisited: A two‐decade prospective study of trajectories of young social assistance recipients

This article revisits earlier research on social assistance (SA) dynamics by applying a holistic life‐course approach, made possible by sequence analysis. We followed the life‐course over 20 years of young recipients of SA in Norway. The data material was derived from administrative data collected and linked by Statistics Norway. The study population was first‐time SA recipients aged 18–24 years in 1995. In addition to SA, spells of social security, schooling, work and earnings were examined. We found that SA plays a minor role over time, but that social security receipt constitutes an important trajectory for more than a quarter of the SA population. Education and work with medium earnings make up distinctly different and rather successful trajectories for about half of the SA population. Gender and early school‐leaving matter for trajectory affiliation. Women’s trajectories are to a greater extent than men’s characterised by unstable employment and low‐paid work.

La atención sanitaria a pacientes con multimorbilidad. La percepción de los profesionales

ObjectiveTo explore the perceptions of health professionals about the characteristics of health care for patients with multimorbidity. DesignQualitative study of phenomenological trajectory made between January and September 2015 through 3 group interviews and 15 individual interviews. LocationAragonese Health Service. ParticipantsMedical and nursing professionals of the Aragon Health Service belonging to various services: Internal Medicine, Primary Care, Emergency and Management. A pharmacist was also included. MethodsA non-probabilistic intentional sampling was carried out that allowed for the selection of professionals in terms of discourse representation criteria, allowing to know and interpret the phenomenon studied in depth, in its different visions. We interviewed health professionals with different profiles who knew in depth the characteristics of care provided to patients with multimorbidity. The interviews were recorded, transcribed literally and interpreted, through the social analysis of the discourse. ResultsProfessional culture oriented to individual pathologies, lack of coordination among professionals, high prevalence of multi-prescriptions, Clinical Practice Guidelines oriented to individual pathologies and specialist training focused on individual diseases. ConclusionsBoth the professional culture and the organization of the healthcare system have been oriented towards the attention to individual pathologies, which results in the difficulty to offer a more integrated care to patients with multimorbidity.

Genome-wide association study of smoking trajectory and meta-analysis of smoking status in 842,000 individuals

Here we report a large genome-wide association study (GWAS) for longitudinal smoking phenotypes in 286,118 individuals from the Million Veteran Program (MVP) where we identified 18 loci for smoking trajectory of current versus never in European Americans, one locus in African Americans, and one in Hispanic Americans. Functional annotations prioritized several dozen genes where significant loci co-localized with either expression quantitative trait loci or chromatin interactions. The smoking trajectories were genetically correlated with 209 complex traits, for 33 of which smoking was either a causal or a consequential factor. We also performed European-ancestry meta-analyses for smoking status in the MVP and GWAS & Sequencing Consortium of Alcohol and Nicotine use (GSCAN) (Ntotal = 842,717) and identified 99 loci for smoking initiation and 13 loci for smoking cessation. Overall, this large GWAS of longitudinal smoking phenotype in multiple populations, combined with a meta-GWAS for smoking status, adds new insights into the genetic vulnerability for smoking behavior.

Space-time in the study of learning trajectories

ABSTRACT Space-time plays a central role in the scientific study of learning trajectories. From a sociocultural perspective, the definition of a set of space-time coordinates enables researchers to identify and examine both the learning activities in which subjects participate and those life events relevant to understanding their learning processes. The present article reports on a systematic literature review that explored the way in which different researchers define space-time coordinates in their work. We identified 24 empirical studies on the subject, analysis of which led us to conclude that the study of learning trajectories requires not only the specific space-time coordinates of those contexts in which a given learning activity takes place, but also the coordinates that people re/co-construct on an experiential or subjective level based on those activities.

Trajectories of Nicotine and Cannabis Vaping and Polyuse From Adolescence to Young Adulthood

Little is known about cannabis vaping trajectories across adolescence and young adulthood or the co-occurrence with nicotine vaping. To evaluate nicotine vaping and cannabis vaping trajectories from late adolescence to young adulthood (≥18 years of age) and the extent of polysubstance vaping. In this prospective cohort study, 5 surveys (including information on substance vaped) were completed at 10 high schools in the Los Angeles, California, metro area. Students were surveyed at 6-month intervals from fall of 11th grade (October to December 2015; wave 5) through spring of 12th grade (March to June 2017; wave 8) and again approximately 1 to 2 years after high school (October 2018 to October 2019; wave 9). Past 30-day nicotine and cannabis vaping frequency across 5 waves. Self-reported frequency of nicotine vaping and cannabis vaping within the past 30 days across 5 time points from late adolescence to young adulthood. Trajectories were measured with these past 30-day use frequencies at each wave. Parallel growth mixture modeling estimated conditional probabilities of polysubstance vaping. The analytic sample included 3322 participants with at least 1 time point of data (mean [SD] age, 16.50 [0.42] years at baseline; 1777 [53.5%] female; 1573 [47.4%] Hispanic or Latino). Growth mixture modeling identified the 5-trajectory model as optimal for both nicotine vaping and cannabis vaping. Trajectories for nicotine and cannabis vaping were similar (nonusers: 2246 [67.6%] nicotine, 2157 [64.9%] cannabis; infrequent users: 566 [17.0%] nicotine, 608 [18.3%] cannabis; moderate users: 167 [5.0%] nicotine, 233 [7.0%] cannabis; young adult-onset frequent users: 213 [6.4%] nicotine, 190 [5.7%] cannabis; adolescent-onset escalating frequent users: 131 [3.9%] nicotine, 134 [4.0%] cannabis). Males had greater odds of belonging to the adolescent-onset escalating frequent users nicotine (adjusted odds ratio, 2.88; 95% CI, 1.58-5.23; P < .01) and cannabis (adjusted odds ratio, 1.95; 95% CI,1.03-3.66; P < .05) vaping trajectories compared with nonusers. Polysubstance vaping was common, with those in trajectories reflecting more frequent nicotine vaping (adolescent-onset escalating frequent users and young adult-onset frequent users) having a high probability of membership (85% and 93%, respectively) in a cannabis-use trajectory. In this cohort study, the prevalence and type of nicotine vaping and cannabis vaping developmental trajectories from late adolescence to young adulthood were similar. Polysubstance vaping was common from late adolescence to young adulthood, particularly among those reporting more frequent vaping use. The findings suggest that public health policy and clinical interventions should address polysubstance vaping in both adolescence and young adulthood.

Capitales, habitus y disposiciones de profesores universitarios. Una aproximación a partir de sus trayectorias académicas / Capitals, habitus and dispositions of university professors. An approximation from their academic careers

Este trabajo rescata el empleo de las herramientas analíticas de Pierre Bourdieu con la finalidad facilitar la articulación y construcción del objeto de estudio, la propuesta teórico-metodológica y, evidentemente, la construcción del dato. El objetivo general fue caracterizar algunos rasgos de la transformación entre capitales, habitus y disposiciones entre profesores universitarios de dos instituciones de educación superior en México. Para tal fin, el objeto de estudio fue construido desde la Teoría de la Economía de las Prácticas Sociales de Bourdieu con la intención de articular la producción de subjetividades a partir de las condiciones objetivas de los agentes sociales (Bourdieu, 1979). Metodológicamente, se recuperaron los momentos establecidos por el sociólogo francés, a saber: 1) analizar la relación del campo frente al campo de poder, 2) trazado de un mapa de la estructura objetiva de las relaciones entre posiciones y 3) analizar el habitus de los agentes (Bourdieu y Wacquant, 2005); operacionalmente, se utilizaron la investigación documental, el análisis multivariante y el método comparado en educación como eje articulador para el análisis y construcción del dato. Los principales resultados sugieren que, derivado de la yuxtaposición de los diversos campos que convergen en el campo educativo, se presentan efectos de transformación de capitales en habitus o bien en disposiciones; la evidencia empírica sugiere que las trayectorias sociales regulan dicha transformación. Finalmente, se concluye la importancia que reviste el estudio de las trayectorias sociales de los profesores, toda vez que los componentes de la subjetividad están relacionados con las condiciones objetivas. This work rescues the use of Bourdieu’s analytical tools to facilitate the articulation and construction of the object of study, the theoretical-methodological proposal, and the construction of the data. The general objective was to characterize some features of the transformation between capitals, habitus, and dispositions based on the academic trajectories of university professors of higher education in México. To this end, the object of study was built from the Theory of the Economics of Social Practices of Bourdieu with the intention of articulating the production of subjectivities based on the objective conditions of agents, so concepts such as field, capitals, habitus, doxa, hysteresis, and allodoxia are recovered. Methodologically and based on the fact that the theoretical perspective of the French sociologist is open and relational, the moments established by him were recovered and they are: 1) analyze the relationship of the field versus the field of power, 2) drawing a map of the objective structure of the relationships between positions and 3) analyze the habitus of the agents (Bourdieu and Wacquant, 2005); operationally, research techniques were used that favor data analysis from a relational and comparative perspective such as documentary research, multivariate analysis and the comparative method in education as an articulator. The selected analysis units were two institutions of the Subsystem of Polytechnic Universities in Mexico. The main results suggest that, derived from the juxtaposition of the various fields that converge in the field of education: (a) identified effects of capital transformation in habitus or in provisions based on the prevalence of one of the fields under study; (b) hysteresis effects were observed, as well as allodoxia traits in teachers’ social practices when involved in the attention of students’ emotional problems; (c) a devaluation of the technological capitals of the productive field became apparent when social agents enter the educational field since academic and symbolic capital prevails in the latter. By way of conclusion, the contrasting of the theoretical-methodological commitment with the empirical structure allowed, to know and recognize the importance of the study of the social trajectories of agents since the components of subjectivity are related to the objective conditions, conditions that, in this case, are regulated, conditioned and mediated by supranational bodies through the model of the educational subsystem under study.

Childhood polyvictimization and marijuana use trajectories.

Despite public sentiment to the contrary, recreational marijuana use is deleterious to adolescent health and development. Prospective studies of marijuana use trajectories and their predictors are needed to differentiate risk profiles and inform intervention strategies. Using data on 15,960 participants in the National Longitudinal Study of Adolescent to Adult Health, variable-centered approaches were used to examine the impact of childhood polyvictimization on marijuana onset, marijuana use from age 15 to 24 years, and marijuana dependence symptoms. Zero-Inflated Poisson latent class growth analysis (ZIP-LCGA) was used to identify marijuana use subgroups, and their associations with childhood polyvictimization were tested via multinomial logit regression within ZIP-LCGA. Results showed that the overall probability and frequency of marijuana use increased throughout adolescence, peaked in early adulthood, and diminished gradually thereafter. Polyvictimization was associated with earlier onset and greater overall use, frequency of use, and dependence symptoms. ZIP-LCGA uncovered four subgroups, including non-users and three classes of users: adolescence-limited users, escalators, and chronic users. Polyvictimization distinguished non-users from all classes of marijuana users. The findings underscore the lasting developmental implications of significant childhood trauma. Children who experience polyvictimization represent a group that may benefit from selective interventions aimed at preventing early, frequent, chronic, and dependent marijuana use.

Analytical study of gyrophase, pitch angle, and normal speed of particles leaving an ideal magnetohydrodynamic discontinuity surface.

Particle populations that have velocity distributions with only a small spread of gyrophase angles are commonly observed in the vicinity of magnetohydrodynamic (MHD) discontinuity surfaces such as collisionless shocks. Previous theoretical particle trajectory studies have concentrated on ion behavior at an ideal planar Earth's bow shock and have either assumed that a gyrotropic incident initial velocity distribution is reflected at the surface or instead focused on unique fixed initial gyrophase and pitch angle values specified by the generation mechanism assumed for the particle. In this analytical study of trajectories of particles departing an ideal planar MHD surface we demonstrate that a particle's initial gyrophase and pitch angle determine completely whether it will escape the surface or return to it, regardless of its initial energy. We identify the region in initial gyrophase-pitch angle space which leads to trajectories that return to the surface of the discontinuity. The speed normal to the surface of a returning particle, which can affect its ability to traverse the discontinuity, is shown to increase or decrease compared to its initial value according only to the orientation of its guiding-center motion in the frame of reference in which the discontinuity is at rest and the incoming plasma flow is aligned with the constant magnetic field. The dependence of our results on the direction of the upstream magnetic field is illustrated. Our general analytical results are discussed in the context of observations at the Earth's bow shock.

Study of Hypothetical Learning Trajectories in Mathematics Learning

Mathematics learning in this era requires teachers to be able to develop learning models that pay attention to the characteristics of students, so it is important for teachers to know the learning trajectory. This study aims to describe the conception of learning trajectory and hypothetical learning trajectory, as well as presenting the design of hypothetical learning trajectories in mathematics learning. Based on the theories studied, it is concluded that a hypothetical learning trajectory is a learning design in the form of allegations on student learning activities based on initial understanding and characteristics of students to achieve higher understanding. HLT has three main components namely learning objectives, learning activities, and hypotheses of the learning process. HLT is used by teachers as a guide to predict and prepare learning flow designs that are appropriate to the stages of student thinking and can improve student learning outcomes. The findings of previous studies show that to design HLT in mathematics learning, educators need to consider student obstacle learning, a hierarchy of material, and learning support capacity, so that learning activities to be hypothesized are built based on these things.

Genetics of early growth traits.

In recent years, genome-wide association studies have shed light on the genetics of early growth and its links with later-life health outcomes. Large-scale datasets and meta-analyses, combined with recently developed analytical methods, have enabled dissection of the maternal and fetal genetic contributions to variation in birth weight. Additionally, longitudinal approaches have shown differences between the genetic contributions to infant, childhood and adult adiposity. In contrast, studies of adult height loci have shown strong associations with early body length and childhood height. Early growth-associated loci provide useful tools for causal analyses: Mendelian randomization (MR) studies have provided evidence that early BMI and height are causally related to a number of adult health outcomes. We advise caution in the design and interpretation of MR studies of birth weight investigating effects of fetal growth on later-life cardiometabolic disease because birth weight is only a crude indicator of fetal growth, and the choice of genetic instrument (maternal or fetal) will greatly influence the interpretation of the results. Most genetic studies of early growth have to date centered on European-ancestry participants and outcomes measured at a single time-point, so key priorities for future studies of early growth genetics are aggregation of large samples of diverse ancestries and longitudinal studies of growth trajectories.

A deep learning functional estimator of optimal dynamics for sampling large deviations

In stochastic systems, numerically sampling the relevant trajectories for the estimation of the large deviation statistics of time-extensive observables requires overcoming their exponential (in space and time) scarcity. The optimal way to access these rare events is by means of an auxiliary dynamics obtained from the original one through the so-called ‘generalised Doob transformation’. While this optimal dynamics is guaranteed to exist its use is often impractical, as to define it requires the often impossible task of diagonalising a (tilted) dynamical generator. While approximate schemes have been devised to overcome this issue they are difficult to automate as they tend to require knowledge of the systems under study. Here we address this problem from the perspective of deep learning. We devise an iterative semi-supervised learning scheme which converges to the optimal or Doob dynamics with the clear advantage of requiring no prior knowledge of the system. We test our method in a paradigmatic statistical mechanics model with non-trivial dynamical fluctuations, the fully packed classical dimer model on the square lattice, showing that it compares favourably with more traditional approaches. We discuss broader implications of our results for the study of rare dynamical trajectories.

The transformation of professors\u2019 careers: standardization, hybridization, and acceleration?

Over the recent decades, the turn to managerial governance has thoroughly transformed the European university systems and, by extension, the careers of university professors. Scholars postulated that professors’ careers have undergone an increasing formalization, that disciplinary careers have been hybridized, and that new modes of selection and recruitment (through assistant professorship) have been introduced. This article, based on a case study of the EPFL Lausanne, one of the leading European technical universities, aims to understand these changes by conducting a sequence analytical study of the actual trajectories of professors. By studying the careers of 351 professors who were nominated between 1969 and 2010 at the EPFL, we first develop a typology of professors’ careers. We distinguish between “direct careers,” “seniority careers,” “conversion careers,” and “parallel careers.” We then examine, based on a series of binomial logistic regression models, how career types vary according to the nomination cohort, the discipline, and the recruitment mode. Our results show that slower “seniority careers” within academia have become more important in recent cohorts, that disciplinary logics still shape professors’ careers, and that new recruitment mechanisms, such as assistant professorship, do not necessarily lead to accelerated careers. This article contributes to the literature by showing that beyond the analysis of the institutional setting of academic careers, it is also important to study their actual progression.

The second season of excavations at Jebel Moya (south-central Sudan)

AbstractThis report presents the latest data from ongoing excavations at Jebel Moya, Sudan. This year saw the opening of five new trenches and continued excavation of an archaeologically rich trench. We have recovered four individual burials, a mud brick wall and a number of animal and archaeobotanical remains. The excavations also yielded a longer pottery sequence, showing clearly that the site was in use by at least the sixth millennium BC. This season confirms the long and complex history of Jebel Moya and provides the material for future studies on population health and subsistence. This season also saw an increase in community engagement and a more detailed study of the various historical trajectories that make up the biography of Jebel Moya.

Entanglement entropy growth in stochastic conformal field theory and the KPZ class

We introduce a model of effective conformal quantum field theory in dimension coupled to stochastic noise, where Kardar-Parisi-Zhang (KPZ) class fluctuations can be observed. The analysis of the quantum dynamics of the scaling operators reduces to the study of random trajectories in a random environment, modeled by Brownian vector fields. We use recent results on random walks in random environments to calculate the time-dependent entanglement entropy of a subsystem interval, starting from a factorized state. We find that the fluctuations of the entropy in the large deviation regime are governed by the universal Tracy-Widom distribution. This enlarges the KPZ class, previously observed in random circuit models, to a family of interacting many-body quantum systems.