Node-node distance distribution for growing networks

We present the simulation of the time evolution of the distance matrix. The result is the node-node distance distribution for various kinds of networks. For the exponential trees, analytical formulas are derived for the moments of the distance distribution.Comment: presented during the 37-th Polish Physicists' Meeting, Gdansk, Poland, 15-19 Sep. 2003, 6 pages, 3 figure

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Academic or student burnout arises from the assumption that students, specifically university students, like any professional, encounter pressures and overloads typical of academic work. The students, like any worker, maintain a relationship of direct and indirect compensation with the university institution, evidenced in financial support, scholarships, recognition or awards. This syndrome affects more those professionals who have direct contact with people and with a humanistic philosophy in their work. Those professions or professionals that need great dedication and involvement are the most affected. In this sense, if it is considered that the situation of a university student entails a load of hours dedicated to the activity similar to those of a profession or trade carried out formally. Objective: To analyze the prevalence of SB, and provide the undergraduate student with tools for self-diagnosis of Burnout syndrome and the empowerment of information to prevent the appearance of the syndrome. A cross-sectional study was conducted. The Atienza 2010 Labor Burnout Scale was used. The respondents participated in a workshop on Burnout and in this framework, with prior consent, the scale was applied. A total of 113 Health Sciences students were surveyed at a private university in Villa Mercedes San Luis. The prevalence of Burnout syndrome in students is 69.8%, with 40.5% moderate and 29.3% severe, 30.2% did not present burnout syndrome. Early detection of SB through the application of EBLA facilitates monitoring and control of occupational health in the educational sector. To achieve educational quality, it is necessary to preserve the health of its members. Burnout levels are high in students and measures must be taken by the authorities to avoid these levels.El burnout académico o estudiantil surge de la presunción de que los estudiantes, específicamente universitarios, al igual que cualquier profesional, se encuentran con presiones y sobrecargas propias de la labor académica. Los estudiantes al igual que cualquier trabajador, mantienen una relación de compensación directa e indirecta con la institución universitaria, evidenciada en apoyos económicos, becas, reconocimientos o premios. Este síndrome afecta más a aquellos profesionales que tienen un contacto directo con las personas y con una filosofía humanística en su trabajo. Aquellas profesiones o profesionales que necesitan de una gran entrega e implicación son las más afectadas. En este sentido si se considera que la situación de estudiante universitario conlleva una carga de horas dedicadas a la actividad similar a las de una profesión u oficio realizado de modo formal. Objetivo: Analizar la prevalencia del SB, y brindar al estudiante de grado, herramientas para el autodiagnóstico de síndrome de Burnout y el empoderamiento de la información para evitar el la aparición del síndrome. Se realizó un estudio de tipo transversal. Se utilizó la Escala de Burnout Laboral de Atienza 2010. Los encuestados participaron en un taller sobre Burnout y en ese marco previo consentimiento se aplicó la escala. Se encuestaron un total de 113 estudiantes de Ciencias de la Salud en una universidad privada de Villa Mercedes San Luis. La prevalencia del síndrome de Burnout en los estudiantes es del 69.8%, con un 40.5% de modo moderado y 29.3% grave, el 30.2% no presentaba síndrome de burnout. La detección temprana de SB mediante aplicación de EBLA facilita seguimiento y control de la salud laboral en sector educativo. Para lograr calidad educativa es necesario preservar la salud de sus miembros. Los niveles de Burnout son elevados en estudiantes y se deben tomar medidas desde las autoridades para evitar estos niveles.

Intelligent Cooperative Control Architecture: A Framework for Performance Improvement Using Safe Learning

Planning for multi-agent systems such as task assignment for teams of limited-fuel unmanned aerial vehicles (UAVs) is challenging due to uncertainties in the assumed models and the very large size of the planning space. Researchers have developed fast cooperative planners based on simple models (e.g., linear and deterministic dynamics), yet inaccuracies in assumed models will impact the resulting performance. Learning techniques are capable of adapting the model and providing better policies asymptotically compared to cooperative planners, yet they often violate the safety conditions of the system due to their exploratory nature. Moreover they frequently require an impractically large number of interactions to perform well. This paper introduces the intelligent Cooperative Control Architecture (iCCA) as a framework for combining cooperative planners and reinforcement learning techniques. iCCA improves the policy of the cooperative planner, while reduces the risk and sample complexity of the learner. Empirical results in gridworld and task assignment for fuel-limited UAV domains with problem sizes up to 9 billion state-action pairs verify the advantage of iCCA over pure learning and planning strategies

Adaptation, coordination, and local interactions via distributed approachability

This paper investigates the relation between cooperation, competition, and local interactions in large distributed multi-agent systems. The main contribution is the game-theoretic problem formulation and solution approach based on the new framework of distributed approachability, and the study of the convergence properties of the resulting game model. Approachability theory is the theory of two-player repeated games with vector payoffs, and distributed approachability is here presented for the first time as an extension to the case where we have a team of agents cooperating against a team of adversaries under local information and interaction structure. The game model turns into a nonlinear differential inclusion, which after a proper design of the control and disturbance policies, presents a consensus term and an exogenous adversarial input. Local interactions enter in the model through a graph topology and the corresponding graph-Laplacian matrix. Given the above model, we turn the original questions on cooperation, competition, and local interactions, into convergence properties of the differential inclusion. In particular, we prove convergence and exponential convergence conditions around zero under general Markovian strategies. We illustrate our results in the case of decentralized organizations with multiple decision-makers

Synchronization in complex networks

Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.Comment: Final version published in Physics Reports. More information available at http://synchronets.googlepages.com

Report on the 2020 ICCAT workshop on small tunas biology studies for growth and reproduction

This report describes the 2020 ICCAT workshop on small tunas biology studies for growth and reproduction, hosted by the Instituto Español de Oceanografía, Málaga, Spain. The major objectives of the workshop were: 1) starting the creation of ageing and reproduction reference sets and, 2) providing more training for the ongoing sample collection and processing to the teams involved in these studies. As approved by the SCRS in 2017, the Small Tuna Species Group intersessional meeting decided to prioritize the collection of biological samples aiming at growth, maturity and stock structure studies on three species: little tunny (Euthynnus alletteratus), Atlantic Bonito (Sarda sarda) and wahoo (Acanthocybium solandri), based on their economic importance and the lack of knowledge on their biology. This work will contribute to the next major advance in the assessment of these three species

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Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops