bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing three dimensional localization system using deep learning and pre-trained architectures for IEEE 802.11 Wi-Fi
Authors: Hamza Aseel Hamoud , Hussein Sabreen Ali , Ismaeel Ghassan Ahmad , Abbas Saad Qasim , Zahra Musadak Maher Abdul , Sabry Ahmad H.
Published: September 2022

The performance of Wi-Fi fingerprinting indoor localization systems (ILS) in indoor environments depends on the channel state information (CSI) that is usually restricted because of the fading effect of the multipath. Commonly referred to as the next positioning generation (NPG), the Wi-Fi™, IEEE 802.11az standard offers physical layer characteristics that allow positioning and enhanced ranging using conventional methods. Therefore, it is essential to create an indoor environment dataset of fingerprints of CIR based on 802.11az signals, and label all these fingerprints by their location data estimate STA locations based on a portion of the dataset for fingerprints. This work develops a model for training a convolutional neural network (CNN) for positioning and localization through generating IEEE® 802.11data. The study includes the use of a trained CNN to predict the position or location of several stations according to fingerprint data. This includes evaluating the performance of the CNN for multiple channel impulses responses (CIRs). Deep learning and Fingerprinting algorithms are employed in Wi-Fi positioning models to create a dataset through sampling the fingerprints channel at recognized positions in an environment. The model predicts the locations of a user according to a signal acknowledged of an unidentified position via a reference database. The work also discusses the influence of antenna array size and channel bandwidth on performance. It is shown that the increased training epochs and number of STAs improve the network performance. The results have been proven by a confusion matrix that summarizes and visualizes the undertaking classification technique. We use a limited dataset for simplicity and last in a short simulation time but a higher performance is achieved by training a larger data.
Development of comprehensive decision support tools in distance learning quality management processes
Authors: Shaporeva Anna , Kopnova Oxana , Shmigirilova Irina , Kukharenko Yevgeniya , Aitymova Aliya
Published: September 2022

The object of this study is the quality of distance learning. The need for procedures to assess the quality of this form of education was manifested most clearly in connection with the COVID-19 pandemic, wars, and other global problems, which predetermine the relevance of the study.
The study considers the construction of a decision support model for assessing the quality of distance learning. Underlying the method is a combination of the method of expert assessments and the criterion model of data analysis, the basic method for analyzing the data obtained is the method of hierarchy analysis.
Structural and functional schemes of the quality management system for distance learning are proposed. During the study, 10 criteria and 52 indicators were selected, and the weight of each indicator was calculated. Based on the weight values obtained, a scheme of the criteria model of decision support was built to assess the quality of distance learning.
During the expert evaluation of the criteria and indicators, it was determined that the weight of indicators within the criterion ranges from 0.09953 to 0.34262. Such a difference in weight values indicates the optimality of the set of indicators within the criterion.
Due to the combination of a criteria-based approach to data analysis in combination with the method of expert assessments, the model can be easily adapted for a point assessment of individual components and finding problem areas in the implementation of distance learning and management decision-making.
The results of the study reported here may be of interest to both heads of educational institutions and employees of services involved in processing information about the organization and reporting for strategic decision-making.
Development of a concept for cybersecurity metrics classification
Authors: Yevseiev Serhii , Milov Oleksandr , Opirskyy Ivan , Dunaievska Olha , Huk Oleksandr , Pogorelov Volodymyr , Bondarenko Kyrylo , Zviertseva Nataliia , Melenti Yevgen , Tomashevsky Bogdan
Published: September 2022

The development of the IT industry and computing resources allows the formation of cyberphysical social systems (CPSS), which are the integration of wireless mobile and Internet technologies and the combination of the Internet of things with the technologies of cyberphysical systems. To build protection systems, while minimizing both computing and economic costs, various sets of security profiles are used, ensuring the continuity of critical business processes. To assess/compare the level of CPSS security, various assessment methods based on a set of metrics are generally used. Security metrics are tools for providing up-to-date information about the state of the security level, cost characteristics/parameters from both the defense and attack sides. However, the choice of such sets is not always the same/understandable to the average person. This, firstly, leads to the absence of a generally accepted and unambiguous definition, which means that one system is more secure than another. Secondly, it does not take into account the signs of synergy and hybridity of modern targeted attacks. Without this knowledge, it is impossible to show that the metric measures the security level objectively. Thirdly, there is no universal formal model for all metrics that could be used for rigorous analysis. The paper explores the possibility of defining a basic formal model (classifier) for analyzing security metrics. The proposed security assessment model takes into account not only the level of secrecy of information resources, the level of provision of security services, but also allows, based on the requirements put forward, forming the necessary set of security assessment metrics, taking into account the requirements for the continuity of business processes. The average value of the provision of security services to CPSS information resources is 0.99, with an average value of the security level of information resources of 0.8
Modifying a method for direct data collection by a telecommunication aerial platform from nodes of wireless sensor networks
Authors: Hrymud Andrii , Romaniuk Valery
Published: September 2022

Wireless sensor networks are becoming increasingly important in both the civilian and military fields. The object of this study is the process of collecting data by a telecommunication aerial platform from network nodes under conditions of their remoteness from the telecommunication infrastructure. Most available papers consider a solution to partial problems related to the process of data acquisition by a telecommunication aerial platform: clustering of the network, search for the shortest flight route, minimization of energy costs of nodes, etc. Therefore, an improved method of direct data collection by a telecommunication air platform is proposed, which consistently and comprehensively solves these problems. Unlike existing methods, it takes into consideration several objective functions (optimization of data collection time by a telecommunication air platform and a network functioning time), parameters of the state of nodes and clusters, as well as makes it possible to obtain solutions in real time. A special feature of the proposed method is the search for the optimal solution according to the hierarchy: network – cluster – node. At the network level, the following is optimized: the number of clusters of a certain dimensionality and the trajectory of the cluster flyby. At the cluster level, the points (intervals) of data collection during the freezing (in motion) of the telecommunication air platform and the trajectory of its flight within a cluster are determined. At the node level, its energy consumption is minimized by reducing the distance to the telecommunication aerial platform. The trajectory of the platform within a cluster is calculated according to the developed rule base. The rules implement the method of situational management. The conditions of application are the parameters of the state of the nodes, the solutions are the parameters of the trajectory of a telecommunication aerial platform, and the intervals of data acquisition. The rules take into consideration the priority of the objective functions, the state of the parameters of the cluster nodes, and the previously made basic decision on the trajectory of the flyby. The simulation results show that the application of the method reduces the time of data collection up to 15 % or increases the network functioning time to 17 %.
Improving a method for eliminating the spill of hazardous substances by using "Universal Absorbent Cloth"
Authors: Zelenko Yuliya , Calimbet Nicolay
Published: September 2022

In order to increase efficiency and implement the principles of resource saving during the elimination of emergency spills of dangerous goods when transporting them by rail, proposals have been offered to improve the method of localization and elimination of emissions of hazardous substances using the "Universal Absorbent Cloth" ("UAC")
The specificity of localization of the emergency emission site and the principles of elimination based on sorption technologies using "UAC" are described.
To manufacture "UAC", special equipment (carbonizer) was designed, which provides effective carbonization of raw materials from plant waste at sufficiently low temperatures ≤500 °C. Using a carbonizer, a universal sorbent was obtained, which is subsequently used for the manufacture of "UAC". The total carbonization time of plant waste samples did not exceed 60 minutes. The universal absorbent obtained during the carbonization process was placed in a fabric matrix to produce "UAC" absorbent cloth.
Standardized procedures for conducting experiments are described. Studies of the adsorption characteristics of the proposed "UAC" involving various model solutions (Gasoline A-95, 25 % solution of ammonia water, and 15 % solution of hydrogen peroxide) confirm its versatility and efficiency; the degree of purification reaches 92 %.
It is proposed to use certain types of railroad cars to transport "UAC" as part of a freight train, which is supported by the corresponding dynamic indicators. Recommendations for the regeneration or disposal of spent "UAC" cloth are provided.
The proposals for improving the method of emergency emission elimination using the "Universal Absorbent Cloth" ("UAC") make it possible to minimize the negative consequences of emergency spills of liquid cargoes of different hazard classes and reduce the time spent on elimination operations. These advantages ensure the competitiveness and profitability of the proposed technology
Privacy protection based distributed clustering with deep learning algorithm for distributed data mining
Authors: Mahmood Alaa Thamer , Kamil Naser Raed , Khalil Abd Sura
Published: September 2022

Distributed Data Mining (DDM) is vital in various applications for processing large volumes of data. The datasets are saved in the local databases and operated by local communities, but it provides the solution locally and globally. However, the datasets are stored in a distributed manner which affects the scalability and reliability issues. In addition, locally stored data is influenced by security and privacy challenges. In addition, the third party may access the DDM, which causes authorization issues. Therefore, the DDM process fuses sensor data from different sources to improve knowledge discovery. During this process, the DDM faces several issues such as security concerns, privacy restrictions, technical barriers, and trust issues. To address these issues, distributed data mining (DDM) should be improved to handle homogeneous and heterogeneous data. This work uses the privacy protection-based distributed clustering (PPDC) algorithm to handle the privacy and security challenges while analyzing the distributed data. The clustering algorithm generates the semi-trusted third parties to form the cluster, which protects the data from unauthorized users. The semi-trusted party protect the locally analyzed solution by creating the random vector-based trusted process. Further, the process uses the optimized deep learning approach and clustering to improve the heterogeneous data analysis. Then the effectiveness of the introduced PPDC method is compared with existing methods, and the PPDC algorithm ensures the 0.202 error rate, 0.95 % of accuracy and manages the data security.
Resource Estimation of Freight Car’s Brake Pads in Operating Conditions
Authors: Ravlyuk V. G , Lamnauer N. Y , Elyazov İ. Sh. oglu , Kyrychenko I. K , Skubak N. M
Published: September 2022

Purpose. This research is aimed at substantiation and development of the correct for practical use model of service life exhaustion of brake pads of freight cars based on mass inspections of their wear using the elements of the statistical conclusions’ theory. Methodology. Production research conducted in several stages, allowed identifying and accumulating sufficient statistics on the malfunctions, failures or defects of the elements of the brake rigging. Statistics on determining the service life of composite brake pads before their complete failure were carried out for a typical and modernized design of the brake rigging of freight cars. The well-known provisions of the theory of statistical conclusions, which are applied to technical brake systems of units and elements of freight cars, were used as research methods. Findings. Empirical characteristics are obtained as a result of current inspections of wear of composite brake pads of brake rigging. This made it possible to achieve more reliable results from the law of random variables distribution concerning the wear of composite brake pads – to limit the service life of pads on the run under conditions of their safe operation. The proposed model of the density distribution function of random variables for composite brake pads allows high accuracy estimating such an important characteristic as the resource threshold. This make it possible to predict the brake pads performance and determine the efficiency of brake rigging of freight car bogies. Originality. For the first time, a correct statistical wear model of composite brake pads of freight cars has been proposed. Based on the developed model the occurrence chronology of clinodual wear of composite brake pads and its influence on a resource of their work in operating conditions is investigated. Field research on experimental bogies of freight cars confirmed that the service life of composite pads has increased by an average of 19% for upgraded brake rigging compared to typical ones. Practical value. The obtained positive results will be taken into account in the future to solve problematic technical issues related to non-standard wear of composite brake pads in the freight cars’ bogies of Ukrzaliznytsia JSC, which will allow extending the interrepair periods.
Deep Attenuation Use for Traction Motors of Mainline Electric Locomotives
Authors: Afanasov A. M , Arpul S. V , Bilukhin D. S , Shemet A. Y. , Vasyliev V. Y , Hololobova O. O , Markul R. V
Published: September 2022

Purpose. Given the need to improve the performance of modern mainline rolling stock, the authors analyze the possibility of using deeper regulation of attenuation. Methodology. The analysis of the operation of the thyristor-pulse converter of ER200 electric train is performed. It is established that in the acceleration mode at the limit traction characteristic it is necessary to consider two zones: the zone of constant value of traction force and the zone of constant power. A method for determining the minimum value of the attenuation coefficient for different types of DC and PC traction motors was proposed. The methods of theoretical research and analytical calculation of electrical circuits, theoretical foundations of electric traction, mathematical modeling of electrical and energy processes were used for the analysis. Findings. The complex of theoretical research and calculations allows confirming the technical possibility of deep attenuation use to regulate the speed regulation and obtain additional across-the-line positions for the rolling stock with DC and PC traction motors. The minimum attenuation coefficient value for different types of traction motors was determined. Originality. The methodology for determining the minimum value of the attenuation coefficient for traction motors of main electric locomotives in terms of using deeper magnetic flux control, replacing the use of experimental research data with theoretical studies. The essence of the studies is to form the required type of the limit traction characteristics by reducing the minimum permissible value of the excitation coefficient, which will reduce the electricity consumption. The research on determination of quantitative indicators of electricity consumption for the analysis of energy saving reserves on the main transport was further developed. Practical value. The results of theoretical research can be the basis for the modernization of main electric locomotives of direct and pulsating current with the systems of deep attenuation regulation. The research conducted will make it possible to create recommendations on designing the systems of magnetic flux regulation for traction engines with the improved technical and economic characteristics which are capable to increase the transport process efficiency on the main transport.
Understanding alcohol-related indicators from population surveys: answering the “Five W’s of Epidemiology”
Authors: Boni Raquel Brandini De
Published: September 2022

The harmful use of alcohol is a major risk factor for the global burden of disease, and public policies are the most effective strategies to prevent it. Population-based surveys are milestones for planning, implementing, and monitoring those policies. However, there are numerous ways to measure alcohol consumption which may result in different indicators. Researchers and stakeholders should find common ground in the understanding of these measures to avoid misinterpretation and confusion in the field. Answering to the “Five W’s Epidemiology”, when interpreting alcohol-related information, may improve the communication, as well as reproducibility and comparability of research findings. This paper aims to exemplify this approach by describing some indicators from the World Health Organization’s Global Information System on Alcohol and Health (GISAH) and the corresponding data available from the latest Brazilian household surveys. Notably, none of the Brazilian surveys reports on all the nine selected GISAH indicators, and only two provided the necessary methodological details to be fully reproducible. A stronger agenda is of the utmost importancefor advancing in the monitoring and prevention of alcohol-related harms in Brazil.
Public health educational projects in Brazil: revealing the influence of contexts - social, political and of the world of work - over time
Authors: Viana Jussara Lisboa , Gusmão João de Oliveira , Marques Maria Cristina da Costa , Castellanos Marcelo Eduardo Pfeiffer , Louvison Marilia Cristina Prado , Akerman Marco
Published: September 2022

ABSTRACT This article analyzes the breadth of experiences of educational projects in Public Health/ Collective Health in Brazil, with an emphasis on contextual elements, so as to point out characteristics and key questions present in the Brazilian experience of this mode of education. The work and education of sanitarians are traced historically, and their contradictions, alignments and perspectives identified. This will be discussed over six different historical periods starting in 1889, on the basis of the following analytical categories: a) socio-political conjunction; b) sanitarians practice; c) educational projects; and d) institutionalization and organization of public health. An analytical table is presented and discussed. Based on it, evidence of the mutual influence over time of socio-health contexts, educational projects and sanitarians world of work is pointed out. The challenge is to provide a counter-hegemonic education vis-à-vis the capitalist model, and that Public Health/Collective Health graduates manage to position themselves and work within this perspective. Making adaptations to the educational project seems valid. However, it may not be enough to alter structural tensions, since the political and economic setting has historically determined ‘for what’, ‘where’, ‘how’ and ‘for whom’ sanitarians work.
Atención Primaria en Salud en una región de la Amazonía colombiana: una aproximación al cotidiano
Authors: Arias-Murcia Saidy Eliana , Penna Cláudia Maria de Mattos
Published: September 2022

RESUMEN En 2016 comenzó en Colombia la implantación de un nuevo modelo de salud con foco en la atención primaria, siendo Guainía, en la Amazonía colombiana, la primera región en iniciar el test piloto. El objetivo de este estudio fue comprender el cotidiano de implementación de la atención primaria, en el marco del Modelo Integral de Atención en Salud, desde la perspectiva de indígenas y profesionales de la salud en Guainía, Colombia. Se trata de un estudio de caso único, con abordaje cualitativo, fundamentado en la sociología comprensiva del cotidiano. Los datos, recolectados mediante observación directa y entrevistas semiestructuradas con 26 profesionales de salud y 22 usuarios indígenas, fueron sometidos a análisis de contenido temático. Emergieron cinco categorías: ‘vivir en el puesto’, ‘resolver solo’, ‘el desafío de la cobertura territorial’, ‘comisiones de salud: solventando vacíos’ y ‘apoyo de líderes locales’. A pesar de la propuesta reestructurante traída por el nuevo modelo, se evidenció en el cotidiano la persistencia de un enfoque asistencialista y basado en la lógica curativista en la prestación de los servicios. Aunque los atributos de la atención primaria se ven comprometidos, se identificaron acciones cotidianas que pueden favorecer la integralidad en la atención y aportar a una transición exitosa.
Saúde Socioambiental na Atenção Básica: conhecimento, formação e prática
Authors: Branco Jeffer Castelo , Batista Nildo Alves , Thomaz Silvia Maria Tagé
Published: September 2022

RESUMO A exposição humana às substâncias e aos compostos químicos nocivos é uma realidade global que torna cada vez mais necessária a promoção da saúde às pessoas e comunidades expostas em seus territórios. Considerando que a Saúde Socioambiental observa o movimento dos agentes nocivos na interface ambiente-saúde-sociedade, buscou-se analisar o conhecimento, a formação e a prática das equipes da Atenção Básica com relação à Saúde Socioambiental, com foco na redução do adoecimento devido à exposição e à intoxicação por esses agentes. Utilizou-se a escala do tipo Likert sem ponto central validada por um grupo de 11 especialistas e 3 profissionais da Atenção Básica. Garantiu-se a existência de mínima dispersão com a administração do estudo e o cálculo do coeficiente de correção linear de Pearson; e boa confiabilidade por meio do teste de coeficiente de confiabilidade de Spearman-Brown, em que foi usado o Split-Half Method. A pesquisa revelou haver situação de conforto na dimensão conhecimento, perigo na dimensão formação, e atenção na dimensão prática. A formação é a única dimensão que, no resultado geral, demanda mudanças imediatas. Ainda que as dimensões conhecimento e prática profissional se apresentem, respectivamente, em situação de manutenção e aprimoramento, essas não se originam de instituições formais de ensino.
Emergency and Urgent Health Care Network on scene: contingencies and production of care
Authors: Tofani Luís Fernando Nogueira , Furtado Lumena Almeida Castro , Andreazza Rosemarie , Nasser Mariana Arantes , Bizetto Olivia Félix , Chioro Arthur
Published: September 2022

ABSTRACT This study aims to analyze the possible transformations in health care management and production processes, in the context of practice, based on the Emergency and Urgent Health Care Network (RUE) policy. The research has a qualitative character and is characterized as a case study. Interviews were conducted with 16 health service managers in four municipalities of different population sizes. The material was analyzed with reference to the context of the Public Policy Cycle Approach practice. It is observed that the RUE is not recognized as a public policy, although some of its elements are identified, such as the implementation of Emergency Care Units, protocols, risk classification, new care technologies, regulatory arrangements, and lines of care. Looking at the ‘RUE on scene’ mainly points to three issues: the relationship between primary care and emergency doors in meeting spontaneous demand; the medical regulation of Mobile Emergency Care Service (SAMU), as a promoter of access and quality; and the (dis)continuity in health care. There is evidence of live movements and productions induced by the policy that qualify health care in urgent and emergency situations. However, inequities are maintained or produced, and the need for articulation between network components, although evoked, translates into fragile and non-regular connections.
O acadêmico de Medicina frente à população em situação de rua: Trabalho Colaborativo como ferramenta
Authors: Sousa Elisabete D’Oliveira Paula , Chagas Magda de Souza
Published: September 2022

RESUMO Trata-se do relato de experiência de uma acadêmica de Medicina da Universidade Federal Fluminense, bolsista do Programa de Educação pelo Trabalho para a Saúde/Interprofissionalidade, atuando integrada ao Consultório na Rua de Niterói (RJ), Brasil entre abril de 2019 e março de 2020. Objetivando-se o reconhecimento de desafios, limites e potencialidades da Educação Interprofissional e do Trabalho Colaborativo, utilizou-se como ferramenta metodológica a narrativa construída por meio de 44 relatórios enviados aos preceptores e tutores do Programa, partilhando-se não apenas o que o campo prático como espaço físico trouxe à luz, mas também o que ganhou vida por meio da intersubjetividade no encontro com diversos personagens. A oportunidade de acompanhar o Consultório na Rua possibilitou à estudante conhecer mais sobre esse serviço essencial para garantia da equidade na saúde da população em situação de rua, levando ao aperfeiçoamento e desenvolvimento de habilidades e ferramentas que irão compor um trabalho centrado na formação de vínculos positivos com usuários do serviço, na oferta do cuidado integral e nas práticas colaborativas em saúde. Concluiu-se que, apesar das inúmeras barreiras, a Educação Interprofissional e o Trabalho Colaborativo constituem importantes instrumentos na formação acadêmica, destacando-se na produção de serviços de saúde de alta qualidade, sobretudo na oferta do cuidado integral às pessoas em vulnerabilidade.
Veterinarian’s perceptions of animal euthanasia and the relation to their own mental health
Authors: Deponti Patrícia Soares , Jaguezeski Antonise Mariely , Pulgatti Dheiny Hellen Venturini , Soares Julio Cesar Mendes , Cecim Marcelo da Silva
Published: September 2022

ABSTRACT: Ethical and moral issues surround the practice of animal euthanasia, which often damages the veterinarian’s mental health, leading to psychological problems and even suicide. This study aimed to evaluate veterinarians’ perceptions about euthanasia and the possible implications of the practice for their mental health and seek to identify gaps in the training of these professionals. Data collection occurred by applying an online questionnaire sent to veterinarians working in the Brazilian territory. Among the 243 participants, 78% said they did not have classes that broadly addressed the practice of animal euthanasia and dysthanasia during undergraduate disciplines; in addition, 71% claimed that they did not address subjects such as medical ethics, psychology, mental health, and verbal communication. The vast majority (90%) considered not trained to deal with patient death, and 67% have already questioned whether the procedure was the best alternative. The presence of sadness after performing euthanasia was frequent among participants. Small animal clinicians were more susceptible to the presence of this feeling when compared to a veterinarian from other areas. Most veterinarians (86%) believed that the practice of animal euthanasia poses risks to the performer’s mental health, and 89% claimed that it influences their mental health. 17% of the participants were using controlled medications during the research period. So, given these findings, it is evident that animal euthanasia negatively affects the mental health of those who perform it. Measures are needed to minimize the impacts arising from the practice, aiming to improve this population’s health and well-being.
Essential oils isolated from popular medicinal plants and spices as alternative antimicrobial and antibiofilm compounds against the pig pathogen Actinobacilluspleuropneumoniae
Authors: Rodrigues Fábio Assad Féres , Silva Giarlã Cunha da , Santana Mateus Ferreira , Bazzolli Denise Mara Soares , Rossi Ciro César , Diaz Marisa Alves Nogueira
Published: September 2022

ABSTRACT: Actinobacilluspleuropneumoniae is the causative agent of swine pleuropneumonia, a contagious respiratory disease associated with high morbidity and economic losses. While antibiotic therapy helps to control the spreading of the pathogen on the farm, resistance to several classes of antibiotics were reported, and treatment can be impaired by the bacterial ability to form biofilms. This increases the need for alternative therapy approaches, including the use of natural compounds with antimicrobial and/or antibiofilm activities. In this research we analyzed, by the broth microdilution method, the inhibitory and bactericidal activities of the essential oils obtained from eighteen Brazilian popular medicinal plants or spices against clinical isolates of Actinobacilluspleuropneumoniae. After that, sub-inhibitory concentrations of active oils were tested for their antibiofilm effects, analyzed by the crystal violet method. Among the eighteen oils tested, eight (extracted from cinnamon, coriander, peppermint, spearmint, thyme, marjoram, eucalyptus, and laurel) presented bacteriostatic and bactericidal activities against all isolates, and subinhibitory concentrations of five of them disrupted up to 80% preformed biofilms, and significantly inhibited biofilm formation. The chemical composition of such oils was assessed by gas chromatography/mass spectrometry (GC/MS) and is presented, indicating that their bactericidal and antibiofilm properties were mostly associated with the presence of monoterpenes and phenylpropanoids. To our knowledge, this is the first report of essential oils with potential to control environmental contamination and animal infection with A. pleuropneumoniae, representing an alternative to increasing levels of antibiotic resistance.
Liquidez em caixa e as restrições financeiras no desempenho de mercado das empresas brasileiras
Authors: Ames Alice Carolina , Nunes Rodolfo Vieira , Silva Tarcísio Pedro da
Published: September 2022

RESUMO O objetivo deste artigo foi verificar a influência da liquidez em caixa e das restrições financeiras no desempenho de mercado das empresas brasileiras. Conforme a Teoria do Pecking Order as organizações optam por lucros retidos sobre as dívidas ou por novas emissões de ações, o que pode estar atrelado a custos específicos. Entretanto, a Teoria do Trade-Off destaca que os impostos têm a proposição de que a política financeira e a dívida podem ser relevantes ao valor da empresa. Assim, esse estudo visa atribuir novos insights para essas temáticas e conhecimento para a investigação da liquidez em caixa e para as restrições financeiras no desempenho. A liquidez em caixa das organizações e as restrições financeiras são fenômenos importantes para o desempenho, haja vista que, no presente estudo, houve aumento no desempenho. Com os resultados, sugere-se que as organizações optem pelo subinvestimento no cenário e pela dificuldade em disposição de crédito. Dessa forma, fica evidente a necessidade de as organizações apresentarem liquidez para não perderem oportunidades de investimento. Apesar de financeiramente restritas, as organizações representam, de certa forma, uma boa opção de investimento, por preferirem o excesso em caixa à disponibilidade para novos investimentos. A população deste estudo é formada pelas empresas listadas na B3 S.A. - Brasil, Bolsa, Balcão. O período de análise correspondeu os anos de 2014 a 2018, sendo realizado cálculo do índice KZ para classificação das organizações quanto ao nível de restrição. Após, ocorreu o cálculo por meio de regressão linear múltipla, com controle de efeitos fixos para ano e setor. Há necessidade de as organizações apresentarem liquidez para atraírem novos investidores. Entretanto, empresas que se encontram financeiramente restritas também podem representar uma boa opção de investimento se optarem pelo excesso em caixa. No mercado, existem algumas resistências quanto a organizações financeiramente restritas, mas nessas pode haver liquidez considerável.
Origem e fama do CEO no desempenho das empresas e na percepção do mercado
Authors: Marcolino Lucas Tresso Caruso , Silva Vinicius Augusto Brunassi
Published: September 2022

Resumo Este artigo investigou as decisões de trocas de chief executive officer (CEO) e as relações entre as características do novo CEO escolhido com o desempenho da empresa e as percepções do mercado de ações. Nosso estudo visa ampliar os entendimentos em uma área ainda pouco explorada pela literatura. Em especial, apresentamos um novo direcionamento para o estudo de Malmendier e Tate (2009) ao abordar a questão do CEO superstar considerando a percepção do mercado acerca da contratação do executivo e seu desempenho na nova empresa. O artigo evidencia uma nova questão de pesquisa que permeia a percepção do mercado acerca da troca de executivos classificados como superstar. Em adição, o estudo conecta as literaturas sobre CEOs superstars e troca de executivos, apresentando novos achados para a temática. Os resultados obtidos trazem novos achados para a literatura e elucidam que CEOs superstars são positivamente avaliados pelo mercado no anúncio da contratação. Contudo, tais executivos não demonstram melhor desempenho que as demais empresas do setor em períodos posteriores, o que corrobora e amplia os aspectos negativos encontrados por Malmendier e Tate (2009). A metodologia usada foi estudo de eventos, MQO, Logit e Probit. O presente artigo evidencia que empresas maiores e com melhor desempenho operacional possuem maior probabilidade de escolher um novo CEO com status de superstar em situações de troca de executivos. CEOs de origem externa e classificados como superstar são, em média, mais bem avaliados do que seus pares pelo mercado na janela de evento referente ao anúncio de contratação. Contudo, o desempenho de tais executivos pode ficar aquém dos resultados apurados para a média dos setores. Os resultados supracitados ampliam a discussão a respeito das decisões de troca de executivos e salientam novos achados sobre o papel da origem do CEO e seu status de reconhecimento e fama.
The role of topographic-derived hydrological variables in explaining plant species distributions in Amazonia
Authors: MOULATLET Gabriel M. , RENNÓ Camilo D. , FIGUEIREDO Fernando O. G. , RUOKOLAINEN Kalle , BANON Lise , EMILIO Thaise , BALSLEV Henrik , TUOMISTO Hanna
Published: September 2022

ABSTRACT In Amazonian terra-firme non inundated forests, local floristic composition and species occurrence are explained by water availability as determined by topographic conditions. Topographic complexity can render these conditions quite variable across the landscape and the effects on plant ecological responses are difficult to document. We used a set of topographically defined hydrological metrics to evaluate community composition and single-species responses of four plant groups [pteridophytes (ferns and lycophytes), Melastomataceae, palms (Arecaceae) and Zingiberales] to topographic conditions in the middle Juruá River region, in western Brazilian Amazonia. The area spans two geological formations (Içá and Solimões) with contrasting topography. River terraces are also found along the main rivers in the area. Local topographic conditions were approximated by height above the nearest drainage (HAND), slope, and Strahler´s drainage order, all obtained from a SRTM digital elevation model (DEM). Data were analyzed using linear and generalized linear mixed models and regression trees. HAND was most successful in explaining floristic composition for all plant groups, except for Melastomataceae, and was more important in the hilly Içá formation than in the Solimões. Individual occurrences of 57% species were predicted by at least one of the topographic variables, suggesting a marked habitat specialization along topographic gradients. For these species, response models using SRTM-DEM-derived variables gave similar results than models using field-measured topography only. Our results suggest that topographical variables estimated from remote sensing can be used to predict local variation in the structure of plant communities in tropical forests.
Abundance of Odonata in different microhabitats at an oxbow lake in the Peruvian Amazon
Authors: MEDINA-ESPINOZA Emmy Fiorella
Published: September 2022

ABSTRACT The relationship between Odonata and vegetation in Amazonia has been studied primarily in streams. In this study, I examined the abundance of adult Odonata in two vegetation types (shrubs and herbs) surrounding an oxbow lake in the Peruvian Amazon. Daytime visual samplings of Odonata were carried out in time blocks along transects in each habitat. Thirteen taxa were identified. Five species were similarly abundant in both habitats, three used mainly herbs, and one mainly shrubs, with no variation among time blocks. The results suggest that most Anisoptera and Zygoptera are adapted to unshaded areas of the lake. Some Odonata also were observed during sunless days with light rainfall, suggesting they are adapted to rainy conditions in tropical climate.
Are larger primates less faunivorous? Consumption of arthropods by Amazonian primates does not fulfil the Jarman-Bell and Kay models
Authors: JESUS Anamélia de Souza , CASTILLA TORRES Reyna Isabel , QUADROS Jean Carlo de , CRUZ Alisson Nogueira , VALSECCHI João , EL BIZRI Hani R. , MAYOR Pedro
Published: September 2022

ABSTRACT Terrestrial arthropod groups, including insects, spiders, and millipedes, represent an important food resource for primates. However, species consumed and patterns and rates of arthropod-related feeding for most frugivorous primates are still poorly known. We examined stomach contents of 178 Amazonian primate specimens of nine genera and three families obtained from community-based collections voluntarily donated by subsistence hunters. Based on our results, we assessed whether consumption patterns followed the expected negative relationship between arthropod ingestion and body size as postulated in the Jarman-Bell and Kay models. We identified 12 consumed arthropod taxa, including insects (beetles, grasshoppers, ants, flies, caterpillars, praying mantises, and others), spiders and millipedes. Medium and large-bodied primates consumed a greater diversity (measured by Simpson’s diversity index) and richness of arthropods, but differed in terms of composition of taxa consumed. Cacajao, Sapajus and Cebus consumed proportionally more Orthoptera and Coleoptera compared to the other primate genera analyzed. We did not find significant correlations between richness and diversity of arthropods consumed and primate body mass. There was a slight tendency for the decrease in the relative content of arthropods in the diet with increased body mass in medium and large primates, which does not provide full support for the Jarman-Bell and Kay models. The study of arthropod consumption by arboreal primates in the wild remains challenging. Our study suggests that arthropods supply essential nutrients for frugivorous primates, and provides an alternative method to analyse faunal consumption patterns in primates.
Mercury bioaccumulation, genotoxic and biochemical biomarkers reveal the health status of yellow-spotted Amazon River turtles (Podocnemis unifilis) in an environmental protection area in the Amazon
Authors: BORGES Ândrocles Oliveira , ERICKSON José , SILVA Lídia Aguiar da , FANTIN Cleiton , DOMINGOS-MOREIRA Fabíola X. V.
Published: September 2022

ABSTRACT Chelonians are considered good bioindicators of environmental quality. The assessment of the health status of chelonian populations in the Amazon is important because they are traditionally consumed in large numbers in riverine communities and sustainable use reserves. The present study aimed to evaluate the health of Podocnemis unifilis (Testudines, Podocnemididae) in an environmental protection area in the Amazon region in Brazil. We analyzed the biomarkers lipoperoxidation, carbonylation of proteins, occurrence of micronuclei and erythrocytic nuclear abnormalities, quantified metallothioneins, and evaluated mercury bioaccumulation. We generated pioneering data regarding biomarkers in wild Amazonian freshwater turtles. All biomarker responses did not vary significantly between the sexes. The occurrence of oxidative and genotoxic damage, as well as concentrations of metallothioneins was low compared to other studies. In addition, the bioaccumulation of mercury in the muscle of the animals was below the limit recommended for human consumption by the World Health Organization. Our results provide baseline data on mercury bioaccumulation and biomarker responses that can be useful for future comparisons with other freshwater turtles. The data also provide evidence that the sustainable exploitation of these turtles in the study area (Piagaçu-Purus Sustainable Development Reserve) does not pose a risk to local riverine communities, as the detected mercury concentrations are safe for human consumption. In this sense, our results highlight the importance of protected areas for the conservation of healthy turtle populations, at the same time ensuring the health of the human populations that use them as a food resource.
Modelo de Evaluación de la Idoneidad Didáctica de un Proceso de Estudio Masivo en el Contexto de la Pandemia de SARS-CoV2
Authors: Malet Omar , Giacomone Belén , Repetto Ana María
Published: September 2022

Resumen Desarrollar herramientas basadas en criterios fundamentados para evaluar un proceso educativo de manera rigurosa y sistemática, y así tomar decisiones orientadas a su mejora, es un asunto de importancia en la agenda de investigación del campo educacional. Si bien son numerosos los trabajos en esa dirección, no se dispone, hasta ahora, de un modelo de evaluación aplicable a cursos masivos. En este artículo se presenta un modelo destinado a valorar la calidad de un proceso de estudio en el que participan numerosos docentes y estudiantes; la asignatura en la que tiene lugar es cuatrimestral, y forma parte del curso de ingreso a una universidad pública nacional. El modelo fue concebido como recurso para la reflexión profesional de quien tiene responsabilidades de coordinación de la asignatura; su diseño resultó compatible con los drásticos cambios que impuso la pandemia de SARS-CoV2. Lo integran dos cuestionarios de carácter censal, uno destinado a los profesores y el otro, a los estudiantes, basados en una adaptación de los criterios generales que conforman la noción de idoneidad didáctica, procedente del Enfoque Ontosemiótico. Los cuestionarios presentan una serie de ítems que operacionalizan el constructo idoneidad y permiten medirlo en una escala intervalar. Se espera que el modelo constituya un aporte para la valoración de la idoneidad de procesos de estudio similares, y, en particular, para la toma de decisiones por parte de quienes los coordinan.
Estratégias de Consagração e de Valorização da Matemática por meio da OBMEP
Authors: Souza Neto João Alves de , Vilela Denise Silva , Farias José Vilani de
Published: September 2022

Resumo Neste artigo apresentamos alguns resultados de pesquisa sobre a Olimpíada Brasileira de Matemática das Escolas Públicas, a OBMEP. Trata-se da maior olimpíada de Matemática do mundo, promovida e organizada por matemáticos de formação, abrangendo escolas de mais de 99% dos municípios do Brasil. O objetivo do artigo é apresentar uma visão sociológica desta competição, de acordo com o referencial teórico-metodológico de Pierre Bourdieu (1930-2002). Com base em um desenho do campo da matemática é possível interpretar a OBMEP como uma estratégia dos matemáticos para valorizar, consagrar e legitimar o seu modo de fazer e de ver a Matemática, impondo essa visão à escola. São analisados documentos, como cartazes, sites de divulgação, artigos e outros materiais de domínio público. Por meio dessa análise, compreendemos que existem práticas de inculcação de crenças, de valorização e de legitimação de uma Matemática, a acadêmica. Veicula-se também, por meio da OBMEP, que é essa Matemática que é base e alavanca para o desenvolvimento científico e tecnológico do País.
Dificultades con la Fracción como Operador en Discentes de Sexto Curso de Educación Primaria
Authors: Herreros-Torres Diana , Sanz Maria T. , Gómez-Ferragud Carlos B.
Published: September 2022

Resumen El presente trabajo, de carácter exploratorio, busca detectar las dificultades presentes en un grupo de discentes de entre once y doce años de edad ante la fracción como operador sobre números naturales y fraccionarios, en dos situaciones diferentes: resolución de problemas y operatoria formal, y con un método aritmético y otro gráfico. Se diseñó una prueba compuesta por dos problemas aritmético verbales dónde la fracción actuaba sobre un número a) natural y b) fraccionario. Así mismo, se les propuso un ejercicio de operatoria formal que reproducía la operación necesaria en los problemas anteriores. Los resultados muestran que el alumnado presenta mayores dificultades cuando la fracción actúa frente a un número fraccionario que cuando se tiene un número natural. En la misma línea, la resolución gráfica no es una herramienta que aumente el éxito en la resolución. Finalmente, el conocimiento de la operación de fracción como operador sobre número fraccionario está fuertemente relacionado con la resolución del problema asociado.
Mujeres migrantes y trabajo doméstico. Experiencias migratorias y de resistencia
Authors: Dutra Delia , Pérez Mirza Aguilar , Magliano María José
Published: September 2022

Resumen La relación entre migraciones femeninas y trabajo doméstico, ya sea remunerado como no remunerado, posee larga data. Producto de la desigualdad social entre géneros, la casa, el cuidado, la reproducción y las tareas domésticas han sido configuradas como patrimonio femenino, lo que ha influido en las experiencias vitales de las mujeres migrantes en su conjunto. Partimos de algunas premisas que nos permiten sistematizar avances y señalar posibilidades de continuidad en el campo de las migraciones internacionales y el trabajo doméstico. En primer lugar, señalamos que la tendencia a que a las mujeres les sean asignadas tareas mayoritariamente en el ámbito de la reproducción social afecta su permanencia en los sectores de actividad denominados productivos, profundizando la segregación ocupacional y la brecha salarial. Segundo, defendemos que el trabajo doméstico, en el entrecruce de sus versiones remuneradas y no remuneradas, es estructurante de los proyectos migratorios que involucran a las mujeres en sus diferentes momentos y etapas. Finalmente, se presentan los artículos que integran este dossier sobre investigaciones realizadas en contexto latinoamericano y español con mujeres trabajadoras migrantes internacionales.