Motion control of mobile autonomous robots using non-linear dynamical systems approach

This paper presents a solution to the problem of motion control of an autonomous robot, moving in a dynamical and unstable environment. It is based on non-linear dynamical systems, modelling the state variables that define the motion of a robot under an omnidirectional platform, like its direction of navigation and velocity. The approach used, is based on a set of non-linear differential equations that model the evolution of state variables along time, based on the concept of attractors and repellers. In the official RoboCup Middle Size League field, a target is used to attract the robot to a certain position (could be the ball or a desired position to receive the ball), while a repeller could move the robot away from its original path (given by obstacles in the surrounding environment). The research was firstly carried out in a computational simulation environment and later on with robots in a real environmentThis work was developed at the Automation and Robotics Laboratory by MINHO R&D TEAM, University of Minho, under the supervision of Professor A. Fernando Ribeiro and A. Gil Lopes. The knowledge exchanging between the RoboCup’s MSL teams and community contributed greatly for the development of this work. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Crosstalk between ROS Homeostasis and Secondary Metabolism in S. natalensis ATCC 27448: Modulation of Pimaricin Production by Intracellular ROS

Streptomyces secondary metabolism is strongly affected by oxygen availability. The increased culture aeration enhances pimaricin production in S. natalensis, however the excess of O2 consumption can lead to an intracellular ROS imbalance that is harmful to the cell. The adaptive physiological response of S. natalensis upon the addition of exogenous H2O2 suggested that the modulation of the intracellular ROS levels, through the activation of the H2O2 inducible catalase during the late exponential growth phase, can alter the production of pimaricin. With the construction of defective mutants on the H2O2 related enzymes SodF, AhpCD and KatA1, an effective and enduring modulation of intracellular ROS was achieved. Characterization of the knock-out strains revealed different behaviours regarding pimaricin production: whilst the superoxide dismutase defective mutant presented low levels of pimaricin production compared to the wild-type, the mutants defective on the H2O2-detoxifying enzymes displayed a pimaricin overproducer phenotype. Using physiological and molecular approaches we report a crosstalk between oxidative stress and secondary metabolism regulatory networks. Our results reveal that the redox-based regulation network triggered by an imbalance of the intracellular ROS homeostasis is also able to modulate the biosynthesis of pimaricin in S. natalensis

DIFERENTES SOLUÇÕES E MÉTODOS DE HIDRATAÇÃO DAS SEMENTES DE SOJA NO POTENCIAL FISIOLÓGICO

O experimento teve o intuito de estudar a qualidade fisiológica de sementes de soja utilizando extrato aquoso de Cyperus rotundus e biorreguladores sintéticos, sob diferentes métodos de hidratação. O estudo foi realizado na Universidade Estadual de Mato Grosso do Sul, Cassilândia-MS, utilizando o delineamento inteiramente casualizado, sendo realizado em duas etapas. Na primeira etapa avaliou-se o desempenho do extrato aquoso de C. rotundus a 3%, comparando-o com: testemunha (sem condicionamento); controle - água; Auxina (IBA) a 0,2%; Stimulate® a 0,2%; Nitrato de Cálcio Ca (NO3)2 a 0,2%. Na segunda etapa aferiu-se o melhor método de condicionamento, utilizando-se de extrato aquoso de C. rotundus 3%, em quatro processos de hidratação: testemunha, submersão, gerbox e entre papéis. Para ambas as etapas, foram realizadas as seguintes avaliações: germinação, índice de velocidade de germinação, condutividade elétrica, emergência das plântulas, índice de emergência, comprimento da parte aérea e das raízes. Em relação ao potencial fisiológico das sementes de soja não é recomendado a hidratação por imersão direta e tampouco o uso de agentes químicos. O fornecimento de extrato aquoso de C. rotundus L. a 3% na solução de hidratação das sementes pelo método de atmosfera umidade e entres folhas de papeis não interfere na germinação e emergência, todavia observa-se maior crescimento do sistema radicular da plântula

Estudo sobre as diferenças interativas e comunicativas das educadoras e das mães com crianças em idade pré-escolar

Os educadores de infância, na ausência dos pais, asseguram cuidados e garantem o bem estar da criança assim como a sua educação e desenvolvimento. A criança estabelece com a maioria dos educadores uma relação afetiva privilegiada mas não de vinculação. O estudo das diferenças e semelhanças entre estes dois tipos de relação permite averiguar a diversidade de relações proporcionadas à criança e o contributo da formação profissional das educadoras no estabelecimento da relação com as crianças. Neste estudo, mães e educadoras são observadas independentemente, na mesma situação quasi-experimental com a criança, como parceiros numa atividade lúdica de construção, sendo analisada a qualidade interativa e comunicativa das díades. Para o efeito, foi pedido a 19 díades mãe-filho(a) e 22 díades educadora-criança que realizassem, em 20 minutos, um produto à sua escolha com os materiais e ferramentas disponibilizados. As crianças tinham entre 3 e 5 anos e não apresentavam problemas de desenvolvimento. Pretendia-se: 1) descrever e comparar os produtos realizados pelas díades mãe-criança e educadora-criança, bem descrever como as escolhas de materiais; 2) comparar a qualidade interativa das mães e das educadoras quanto à empatia, atenção, reciprocidade, cooperação, elaboração/fantasia e desafio proposto; e 3) a qualidade da comunicação quanto ao uso de sugestões, perguntas, ordens, elogios e críticas. Os dados indicam que as educadoras deram mais espaço para a atuação da criança, enquanto as mães procuraram cumprir o tempo da tarefa e aprimorar o produto com as crianças. As mães usaram o reforço verbal para organizar a atividade, impor limites/regras e motivar a criança, enquanto as educadoras recorreram à comunicação oral para transmitir conteúdos e dirigir a atividade.Abstract The educators, in the absence of parents, provide care and ensure the welfare of the child as well as their education and development. Educators are children significant emotional figures but parents are attachment figures. The study of behavioral differences and similarities between educators and mothers can contribute to our knowledge about these two types of relationships and to observe how the educators training can contribute for their interaction with the children. In this study, mothers and educators are observed independently in the same semi experimental situation with the child, as partners in a playful activity of construction, and the interactive and communicative quality of dyads is analyzed. For this purpose, 19 dyads mother-child and 22 teacher-child dyads were asked to make in 20 minutes a product of their choice with the materials and tools available. The children were between 3 and 5 years old without developing problems. The aims of this study was to: 1) describe and compare the products made by the mother and educator dyads’, as well as their choice of materials; 2) compare the quality of mothers and educators’ interaction as well as their empathy, attention, reciprocity, cooperation, development/fantasy and proposed challenge; and 3) the quality of communication as well as suggestions, questions, directions and positive or negative feedback. Our findings indicate that the educators allow and support the child's actions while mothers were more focused on compliance with the time and product improvement. Mothers used the verbal reinforcement to organize the activity, to set limits/rules and to motivate the child while the educators relied on verbal communication to introduce contents and organize the activity.Résumé La recherche sur la qualité des interactions, la communication et l’activité entre enfants et adultes, s’est développé en grande partie autour des figures féminines, restant à clarifier le rôle des hommes comme partenaires affectives et promoteurs du développement et bien-être de l’enfant. Nous avons voulu étudier le comportement des éducateurs et des pères avec des enfants âgés de 3 à 5 ans, sans problèmes de développement. En cette étude, 10 éducateurs (avec une fille et avec un garçon) et 17 pères (avec son fils ou sa fille) ont été observés indépendamment, dans la même situation semi-expérimentale. Nous leur avons demandé de réaliser en 20 minutes un produit, à sa guise, avec les matériels et les outils mis à leur disposition. Nous prétendions une description et comparaison entre les deux groupes relative : i) aux produits réalisés et les matériels et outils utilisés ; ii) à l’empathie, attention, réciprocité, coopération, élaboration/fantaisie et défi proposé ; et iii) à la qualité de la communication verbal. L’étude indique l’existence de styles d’activité et coopération distinctes dans les deux groupes étudiés. Comparativement aux pères, les éducateurs ont stimulé davantage l’exploration de nouveaux problèmes et concepts. Dans les dyades père-enfant les produits avaient été réalisés faisant recours à plus d’outils et ils avaient plus d’éléments. En plus, les pères ont émis plus des questions de processus et des éloges comparativement aux éducateurs qui, a leur tour, ont émis plus des questions de contenu, suggestions et critiques. À la lumière de la recherche antérieure, nous avons réfléchi sur les rôles des figures masculines dans l’éducation de la petite enfance et dans la famille, et son apport au développement de l’enfant.info:eu-repo/semantics/publishedVersio

Estudo sobre as diferenças interativas e comunicativas de educadores e educadoras com crianças em idade em pré-escolar

A educação de infância tem sido assegurada maioritariamente por mulheres e associada ao género feminino. Recentemente, o número de homens na profissão aumentou na Europa. Contudo, o contributo do educador masculino tem sido pouco estudado. No intuito de contribuir para esse corpo de conhecimento, procurámos estudar as diferenças e semelhanças nos comportamentos interativos dos educadores e das educadoras com crianças de 3 anos sem problemas de desenvolvimento. Neste estudo, educadores e educadoras foram observados independentemente na mesma situação experimental como parceiros numa atividade lúdica de construção, sendo analisada a qualidade interativa e comunicativa dos Educadores. Para o efeito, foi pedido a 10 educadores e 11 educadoras que realizassem, em 20 minutos, um produto com as crianças com os materiais e ferramentas disponibilizadas à escolha de ambos. Pretendia-se: i) descrever e comparar os produtos realizados pelas díades masculinas e femininas, bem como as escolhas de materiais; ii) comparar a qualidade interativa dos educadores e das educadoras quanto à empatia, atenção, reciprocidade, cooperação, elaboração/fantasia e desafio proposto; e iii) a qualidade da comunicação. Os dados parecem indicar que existem algumas diferenças na forma de comunicar das educadoras e dos educadores mas poucas diferenças na qualidade interativa. A experiência profissional, a situação de emprego e o facto de serem ou não pais condicionou o comportamento dos Educadores.Abstract Early childhood education has been ensured mostly by women, and this profession is traditionally associated with the feminine gender. Recently, the number of men in this profession has increased in Europe. However, the role of the male educator is understudied. In order to contribute to this body of knowledge, we studied the differences and similarities of the interactive behavior of male and female educators with children with 3 years old without developmental problems. In this study, female and male educators were observed independently in the same experimental situation as partners with the child in a playful activity of construction. Later, we analyzed the interactive and communicative quality of Educators. For that purpose, 10 male educators and 11 female educators built a product of their choice, with the child, with the materials and tools available in about 20 minutes. This study aims were to: i) describe and compare products made by male and female dyads, as well as the choice of materials; ii) compare the interactive behavior of male and female educators regarding empathy, ability to challenge the child, dialogical interaction, communication contends and cooperativity with child; and iii) the quality of communication. Our findings indicate differences in the way male and female educators communicate but fewer differences in the interactive quality. The professional experience, employment status and parenthood seemed to affect their behavior.info:eu-repo/semantics/publishedVersio

Estudo comparativo acerca do comportamento e comunicação materna e paterna em atividade conjunta com os seus filhos de idade pré-escolar

The previous research performed in children life contexts tend to describe fathers as non-directive playmates; while mothers tend to reinforce the communication during interactions and involve affectively the child. When mothers are playmates and fathers give basic care to their child the quality of the interaction of mother-infant and father-infant increases considerably. In this study, fathers and mothers were observed independently in the same semi-experimental play situation with their children. For this purpose, 19 dyads mother-infant and 17 dyads father-infant participated in this 20 minutes experience, to manufacture one product using the materials and tools available to one’s choice. Children were between 3 and 5 years old and had no developmental problems identified. We aimed to: (i) compare the interactive quality of parents related to empathy, reciprocity, cooperation, fantasy and challenge; (ii) the communication quality and (iii) describe and compare the products made by the dyads mother-infant and father-infant, as well as the chosen materials. Our findings indicate few differences between mothers and fathers behaviour. In terms of communication, mothers communicate more with process questions than parents. The major differences correspond to how parents react to boys and girls, giving girls more freedom to explore, more positive feedback, and being more responsive to their emotions. The boys lost more often interest during the activity than the girls. Children’s gender affected the results more than the parents’, which indicates that the parents interact and communicate distinctly with girls and boys. Additionally, parents’ educational level correlated with more attentive, patient, and cooperative behaviour with their children. Regarding the age of the parents: younger parents and with more children use more materials and tools.A investigação tende a descrever o pai como parceiro de jogo que favorece a liberdade de ação; enquanto a mãe, tende a reforçar a comunicação nas interações, envolvendo afetivamente a criança. Nos casos em que a mãe brinca e o pai presta cuidados básicos à criança, a qualidade da interação pai-filhos aumenta consideravelmente. Neste estudo, observamos pai e mãe independentemente na mesma situação experimental como parceiros da criança numa atividade lúdica de construção. Comparamos os seus comportamentos quando colocados no mesmo papel. Para o efeito, foi pedido a 19 díades mãe-filho(a) e 17 díades pai-filho(a) que realizassem, em 20 minutos, um produto à sua escolha com os materiais e ferramentas disponibilizados. As crianças tinham entre 3 e 5 anos, sem atrasos de desenvolvimento identificados. Pretendemos descrever e comparar os pais (mães e pais considerados em conjunto) quanto: (i) à empatia, atenção, reciprocidade, cooperação, elaboração/fantasia e desafio proposto; (ii) à qualidade da comunicação; e (iii) aos produtos realizados e escolhas de materiais. Os nossos resultados indicam poucas diferenças entre pais e mães. Em termos de comunicação, as mães realizam mais perguntas de processo do que os pais. As diferenças mais relevantes correspondem à forma como os pais e as mães reagem com os meninos e as meninas, dando maior liberdade de ação às meninas, mais feedback positivo e revelando-se mais sensíveis a responder às suas emoções. Os meninos perderam mais interesse durante a atividade e revelaram mais sinais de aborrecimento do que as meninas. O sexo das crianças afetou mais os resultados do que o dos pais, ou seja, os pais interagiram e comunicaram distintamente com meninas e meninos. Adicionalmente, a escolaridade dos pais correlacionou-se com comportamentos mais atentos, pacientes e cooperativos dos pais. Relativamente à idade dos progenitores, os pais mais novos e com mais filhos usaram mais materiais e ferramentas

Effects of hydrological dynamics in controlling phosphorus bioavailability in intermittent rivers and implications for estuaries

Several studies on intermittent rivers and ephemeral streams (IRES) have focused on the ecology of populations and communities, and very few explored the biogeochemistry and bioavailability of key elements, such as phosphorus (P) and nitrogen (N). In this study, we aimed to explore the role of environmental seasonality on P bioavailability in an intermittent river in Northeastern Brazil and the implications for nutrient dynamics to downstream ecosystems, such as the estuaries. The study was performed at the Cruxati River, located in the Litoral Hydrographic Basin on the coast of Ceará State, Brazil. We sampled riverine sediments during three hydroperiods (i.e., dry, rewetting, and flow) according to the theoretical model for research in intermittent rivers. We performed a geochemical fractionation of different P forms and determined the physicochemical parameters, particle size distribution, mineralogy, and total organic carbon of the sediments. Mean values were compared using the Kruskal–Wallis non-parametric statistical test (p-value < 0.05) and by discriminant function analysis. We observed that the predominant fractions of P were associated with Fe-oxides, silicates, and refractory organic matter, but there were no statistical differences among these fractions for all hydroperiods. The exchangeable-P form was higher in the dry and flow periods than in the rewetting period. On the opposite side, P associated with humic acids and carbonates was lower in the dry and flow periods but higher in the rewetting period. We concluded that seasonality influences the bioavailability of P in intermittent rivers, being strongly influenced by the organic fraction, including the humic acid fraction and the refractory organic matter, which are important sources of P in the aquatic system. Furthermore, the IRES may act as a source or a sink of nutrients throughout the cycles of wetting and drying, which may release P from the sediments to the aquatic environment. Hence, IRES plays an important role in transporting nutrients to estuaries and maintaining their ecosystem services

Bridging soil biogeochemistry and microbial communities (archaea and bacteria) in tropical seagrass meadows

IntroductionSeagrass meadows are among the most valuable ecosystems, providing numerous ecosystem services and functions. Despite its importance, there is a lack of knowledge about soil’s biogeochemical process variability, which can control microbiological communities. Thus, this study aimed to evaluate whether seagrass meadows in different geo-environments exhibit varying Fe and sulfate reduction intensities, shaping distinct archaea and bacteria communities.MethodsSoil samples were collected in seagrass meadows under contrasting climatic, geological, vegetational and hydrological settings along the Brazilian coast (e.g., Semiarid Coast - SC, Southeastern Granitic Coast – GC, and Southern Quaternary Coast - QC). The soils were characterized by particle size, pH, redox potential (Eh), total organic C and total N content, acid-volatile sulfides (AVS), and simultaneously extracted Fe. Furthermore, a solid-phase Fe fractionation was performed to characterize the decomposition pathways in these soils, and the shifts in the microbial community along this spatial variation were analyzed using denaturing gradient gel electrophoresis.ResultsThe studied soils presented a sandy texture (values ranging from 74 ± 11.8 to 80.5 ± 6.4%) caused by energetic hydrodynamic conditions. The pH values were circumneutral, while redox conditions presented significant distinction among the studied sites, ranging from anoxic to oxic (values ranging from -63 to +334 mV). The degree of pyritization (DOP) ranged from< 10% to values higher than 80%, highly influenced by rhizospheric oxidation, and higher AVS content was recorded for sites with lower DOP (i.e., GC and QC).DiscussionsThus, biogeochemical processes in the seagrass soils present a wide variation in response to the geo-environmental settings. Plants influence the soil’s geochemical and microbiological communities, retaining fine particles, promoting rhizosphere oxidation, and inducing anoxic conditions controlling the Fe and S forms. Moreover, the same plant species can result in distinct soil conditions and microbial communities due to geoenvironmental settings

A prediction rule to stratify mortality risk of patients with pulmonary tuberculosis

Tuberculosis imposes high human and economic tolls, including in Europe. This study was conducted to develop a severity assessment tool for stratifying mortality risk in pulmonary tuberculosis (PTB) patients. A derivation cohort of 681 PTB cases was retrospectively reviewed to generate a model based on multiple logistic regression analysis of prognostic variables with 6-month mortality as the outcome measure. A clinical scoring system was developed and tested against a validation cohort of 103 patients. Five risk features were selected for the prediction model: hypoxemic respiratory failure (OR 4.7, 95% CI 2.8-7.9), age >= 50 years (OR 2.9, 95% CI 1.7-4.8), bilateral lung involvement (OR 2.5, 95% CI 1.44.4), >= 1 significant comorbidity-HIV infection, diabetes mellitus, liver failure or cirrhosis, congestive heart failure and chronic respiratory disease-(OR 2.3, 95% CI 1.3-3.8), and hemoglobin = 6) mortality risk. The mortality associated with each group was 2.9%, 22.9% and 53.9%, respectively. The model performed equally well in the validation cohort. We provide a new, easy-to-use clinical scoring system to identify PTB patients with high-mortality risk in settings with good healthcare access, helping clinicians to decide which patients are in need of closer medical care during treatment.This work was supported by Fundacao Amelia de Mello/Jose de Mello Saude and Sociedade Portuguesa de Pneumologia (SPP). This work was developed under the scope of the project NORTE-01-0145-FEDER-000013, supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER). NSO is a FCT (Fundacao para a Ciencia e Tecnologia) investigator. MS is an Associate FCT Investigator. The fundershad no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript