bluuebunny/crossref_metadata_2025 huggingface dataset:
Rumo à Delegação Escalável e Segura de Gerenciamento de LANs para ISPs
Authors: Temp Daniel , Mansilha Rodrigo , Rodrigues Deivid , Kreutz Diego
Published: May 2021

Conforme os processos pessoais (entretenimento, financeiros, segurança, etc.), suportados por uma gama crescente de dispositivos (TVs, celulares, câmeras, etc.), convergem para serviços oferecidos através da Internet of Things (IoT), os quesitos de Quality of Experience (QoE), segurança e privacidade das Local Area Networks (LANs) residenciais aumentam em complexidade (quantidade, variedade e conflitos entre aplicações e requisitos). Nesse contexto, clientes podem demandar de seus Internet Service Providers (ISPs) soluções para problemas originados em suas LANs. Porém, ISPs enfrentam desafios para atender tal demanda de maneira escalável (i.e. padronizada, em contraste com meios ad-hoc). Objetivamos realizar uma ponte entre as soluções existentes e o mercado para superar especificidades regionais como aspectos financeiros (e.g. custo total de propriedade), legais (e.g. marco legal da Internet Brasileira) e sociais (e.g. conhecimento tecnológico de clientes e técnicos de ISPs) rumo à delegação escalável (i.e. padronizada entre clientes), segura (e.g. controlada e auditável) de gerenciamento de LANs para ISPs. Nossa visão é simplificar ao máximo (i.e. modelo On/Off com temporizador) o processo de delegação de gerência para minimizar custos (hardware, software e treinamento) e facilitar a compreensão dos envolvidos sobre os compromissos de segurança (controle e auditabilidade) envolvidos e assim viabilizar inovação nas bordas da Internet.
Rumo à visibilidade total da rede: uma estratégia adaptativa para coordenadar a coleta de dados de telemetria in-band
Authors: Hohemberger Rumenigue , Rossi Fabio , Luizelli Marcelo Caggiani
Published: May 2021

As redes programáveis vem ganhando espaço frente as redes tracionais principalmente no que diz respeito a capacidade e a velocidade de reorganização para atender as demandas de aplicações. Quanto as formas de monitoramento não foi diferente. Em um gerenciamento de redes pró-ativo, a visualização dos eventos que ocorrem na rede consiste em um fator primordial na busca e verificação rápida de qualquer anomalia que possa ocorrer, e que tenha a capacidade de influenciar no desempenho da rede. A maioria das anomalias de rede são arbitrárias e imprevisíveis, o que aumenta o desafio de monitoramento de tais problemas. As técnicas de monitoramento de rede tradicionais não conseguem inspecionar todos os dados necessários em redes atuais, devido a demanda crescente dos fluxos de rede das aplicações por recursos. Baseado nessas limitações, e o suporte das redes atuais às novas tecnologias de redes programáveis, a In-Band Network Telemetry Orchestration se apresenta como uma proposta viável de gerenciamento de fluxos, com o menor impacto no desempenho da rede e suas aplicações
Um serviço para prover autenticação e revogação de nós na rede DHT
Authors: Garcia Jean , Dias Lucas , Rizzetti Tiago Antônio
Published: May 2021

Este artigo tem como objetivo propor e implementar um serviço para prover autenticação na rede DHT através de certificados digitais, além disso oferecer uma forma reativa de revogação de nós.
Utilização de blockchain para certificação de sistema de gestão de processos e documentos eletrônicos
Authors: De Souza Gomes Thales Júnior , R. Andrade Ewerton
Published: May 2021

A utilização de sistemas de gestão de processos e documentos eletrônicos é uma realidade. Contudo, na maioria das vezes, esses sistemas baseiam-se em modelos centralizados, onde seus administradores possuem privilégios elevados. Neste sentido, este trabalho busca desenvolver uma blockchain com API padronizada e integrável; visando coibir ataques de gestores mal intencionados e descentralizar o armazenamento e manipulação dos processos e documentos eletrônicos, porém, mantendo as proteções de cada sistema e adicionando novos mecanismos de segurança. Para demonstrar a viabilidade da proposta, desenvolveu-se uma blockchain privada, utilizando-se uma API-REST com todas funcionalidades necessárias para realizar as transações.
Desenvolvimento de um agente SNMP para monitoramento de ambientes empresariais
Authors: Dalcin Gerson , Becker Ricardo
Published: May 2021

Conforme tendência da indústria 4.0, o monitoramento e busca de dados sobre máquinas está cada vez mais insurgente. As tecnologias IoT buscam auxiliar nas soluções em coleta de dados e facilitar a comunicação entre dispositivos de rede. O protocolo SNMP se caracteriza por ser robusto e de simples manuseio para a coleta de dados e monitoramento dos ativos. Este artigo apresenta a proposta de desenvolvimento de um agente SNMP modular para monitoramento a nível empresarial e/ou industrial.
Um controlador para um protocolo MAC híbrido em redes sem-fio baseado em aprendizado por reforço
Authors: B. Sousa Camilla , M. Sobral Marcelo
Published: May 2021

Neste trabalho, propõe-se um mecanismo baseado em aprendizado por reforço para escolher o modo de operação de um protocolo MAC híbrido, dependendo da carga de tráfego existente na rede sem-fio. Protocolos como esse combinam MAC do tipo CSMA/CA e TDMA, buscando proporcionar maiores vazões (throughput) e menores latências, e têm sido usados em redes de acesso sem-fio com tecnologia IEEE 802.11. Este trabalho apresenta um modelo para um controlador para esse tipo de MAC, o qual usa experiência para aprender a escolher o melhor modo de operação dependendo da percepção sobre o estado da rede.
Uma Avaliação do uso de MQTT para a Implementação de Digital Twins
Authors: Trevisan Rafael , Knebel Francisco Paiva , Wickboldt Juliano Araújo
Published: May 2021

O conceito de Digital Twin tem se tornado cada dia mais importante como um método para monitorar elementos e prevenir possíveis defeitos. Uma das tecnologias que pode ser usada para implementar a comunicação de dados desse software é o MQTT. Este trabalho avaliou o uso dessa tecnologia nesse contexto e constatou que existe uma limitação do broker na capacidade de envio de mensagens, que pode ser contornada através da utilização de múltiplos brokers em paralelo. Também foi examinado o comportamento dos brokers em situações onde eles estão centralizados em uma máquina com mais recursos computacionais e quando eles estão distribuídos em máquinas exclusivas, porém com menos recursos. Nessas situações constatamos que os brokers apresentam um comportamento mais estável quando seus serviços estão centralizados.
Uma Proposta Inicial baseada em Mobile Edge Computing para Orquestrar Caches em Redes 5G
Authors: Alves Marisangila , Koslovski Guilherme Piêgas
Published: May 2021

A quinta geração de redes móveis 5G é uma tecnologia em evolução e, portanto, existem questões abertas e um número substancial de propostas que visam atender seus requisitos. Dessa forma, pesquisas sugerem a dissipação de servidores cache na periferia da Internet com a arquitetura distribuída proposta pelo paradigma de Mobile Edge Computing. Esse artigo descreve uma proposta preliminar para otimizar o uso servidores cache e diminuir a latência, requisito da 5G. Com base na ponderação de latência e recursos do servidor, o algoritmo decide entre buscar o conteúdo na sua origem ou redirecionar o usuário para outro servidor cache presente na rede.
Um mecanismo para redundância de dados entre Brokers MQTT com uso de Distributed Hash Table
Authors: Dias Lucas Vargas , Eichner André Rech , A. Rizzetti Tiago
Published: May 2021

O Message Queuing Telemetry Transport (MQTT) é um protocolo de entrega de mensagens para dispositivos no conceito de Internet das Coisas (IoT). Ele usa do paradigma Publisher/Subscriber. Os clientes trocam mensagens através de um broker, assim, criando um pontoúnico de falha. Algumas soluções apresentadas na literatura propõem um cluster para balanceamento de carga como mecanismo de defesa. Entretanto, a disponibilidade dos dados não é tratada. Este trabalho apresenta a implementação de um mecanismo para sincronismo e redundância de dados entre brokers MQTT com uso da rede Distributed Hash Table (DHT).
Investigando o Uso de CoAP em ataques DRDoS
Authors: R. Utech Guilherme , R. Obelheiro Rafael
Published: May 2021

Ataques distribuídos de negação de serviço por reﬂexão (Distributed Reﬂection Denial of Service, DRDoS) são ataques realizados pela Internet que visam saturar vítimas com tráfego de rede, causando assim a indisponibilidade de serviços e/ou da própria rede. Um dos protocolos mais recentes no cenários de DRDoS é o CoAP (Constrained Application Protocol), voltado a dispositivos IoT. Este trabalho descreve um honeypot desenvolvido para observar ataques DRDoS usando o CoAP, e apresenta uma análise preliminar de dados coletados pelo honeypot durante um período de cinco meses.
Enabling security in software-defined wireless sensor networks for internet of things
Authors: M. G. de Toledo Cézar , A. G. de Oliveira Doriedson , A. Simplicio Jr Marcos , B. Margi Cintia
Published: May 2021

In Software-Defined Wireless Sensor Networks (SDWSN), a logically centralized controller manages data ﬂows according to high level policies. As a result, it provides Wireless Sensor Networks (WSN) with further ﬂexibility and control over its nodes’ behavior. One challenge in this scenario, though, is that SDWSN are mainly composed of resource-constrained devices, which hinders the application of traditional cryptographic protocols in such networks. In this article, we propose a secure framework for SDWSN that takes into account such constraints, enabling the establishment of end-to-end security among nodes and between nodes and the SDN controller. Besides showing how our proposal can enforce different security services in an SDWSN, we also simulate our framework and present a preliminary security cost of framework.
Segurança de contêineres: taxonomia baseada na arquitetura
Authors: Jensen Nikolas , C. Miers Charles
Published: May 2021

Os contêineres visam uma melhor eficiência no uso dos recursos computacionais ao mesmo tempo que fornecem um ambiente virtualizado para aplicações, mas crescem as preocupações sobre a segurança destes. Contudo, devido ao desfalque na segurança de sua utilização, as empresas e usuários se mantêm receosos ao implementá-lo nas suas aplicações. Este trabalho é propõe uma taxonomia mapeando problemas de segurança conhecidos dos contêineres. Este trabalho é propõe uma taxonomia mapeando problemas de segurança conhecidos dos contêineres. Esta taxonomia aborda os pontos principais desta tecnologia, sem foco num tipo de contêiner específico e também classificando os problemas em suas determinadas categorias.
Viralização de Questionários Online: desafios e oportunidades
Authors: El Uri Maurício , Kreutz Rafael , Fiorenza Maurício , Kreutz Diego , Escarrone Thiago , Temp Daniel , Nunez Vinicius , B. Mansilha Rodrigo
Published: May 2021

Nosúltimos anos, temos observado um aumento na quantidade de coletas de dados realizadas através de questionários online. A partir da coleta e análise de 64 questionários online, mostramos como o uso desse recurso é suscetível a usuários maliciosos, que podem agir de forma automatizada no comprometimento da confiabilidade dos dados coletados. Os questionários dos principais sistemas empregados, como Google Forms, foram submetidos a testes básicos de segurança, como personificação e poluição de conteúdo. Os resultados apontam que a maioria dos questionários criados e aplicados online é suscetível a ataques do tipo sybil. Além disso, verificamos que a maioria dos sistemas de criação dos questionários online é desprovida de recursos cruciais para algumas pesquisas, como a limitação do grupo de respondentes, a privacidade e a confidencialidade dos dados coletados.
UMBU: Um Framework para Experimentação e Avaliação de QoE em Transmissões Multimídia
Authors: De Azevedo Carlos , P. Neto Emídio , Dos Santos Charles , Silva Felipe , Venâncio Neto Augusto
Published: May 2021

Dentre as principais soluções disponíveis para análise de Qualidade de Experiência (QoE) em transmissões multimídia, o EvalVid se apresenta como a principal referência em código aberto dessa área. No entanto, esta ferramenta possui inúmeras deﬁciências, que vão desde a instalação até a análise do QoE, impondo sérias restrições que limitam a operacionalização de avaliações em larga escala. Em vista disso, este trabalho propõe um avanço no campo da experimentação de QoE em transmissões multimídia através do Uniﬁed Multimedia-based Network Evaluation Platform (UMBU), um framework para experimentação e avaliação cujo objetivo é fornecer uma interface que possibilita acesso ubíquo para o gerenciamento reﬁnado sobre as operações relacionadas aos experimentos, além de prover uma série de mecanismos que possibilitam a realização de múltiplas avaliações de maneira escalável e ﬂexível.
Eleição de Líder com Qualidade de Serviço para o Modelo Falha-e-Recuperação
Authors: Reis Vinícius , Vieira Gustavo
Published: May 2021

Um dos objetivos de um sistema distribuído é prover poder computacional e persistência de dados mesmo na presença de falhas de um subconjunto de enlaces e processos. Para determinar quais são os processos defeituosos deste sistema e abstrair o conceito de tempo, estes sistemas utilizam os serviços de um detector de falhas não confiável, encapsulado em um algoritmo de eleição de líder. Embora a literatura sobre a qualidade de serviço (QoS) oferecida por detectores de falhas seja abundante, ela é escassa quando se trata da QoS oferecida por algoritmos de eleição de líder. Nesta dissertação propomos um algoritmo de eleição de líder para o modelo falha-e-recuperação denominado NFD-L, que segue as especificações de QoS originalmente apresentadas em [Chen et al. 2002]. Utilizamos NFD-L em uma aplicação para replicação, como mecanismo de eleição de coordenador para Paxos e apresentamos uma análise da QoS observada, comparando o seu comportamento com um algoritmo de eleição de líder que não foi projetado explicitamente para prover garantias de QoS.
iSim: Uma Estratégia de Agrupamento de Usuários para Descarregamento de Dados em Redes Móveis Centradas na Informação
Authors: Ribeiro Adriana , Sampaio Leobino
Published: May 2021

Este artigo apresenta a iSim, uma estratégia de cálculo de similaridade e agrupamento entre usuários baseada na diversidade e na frequência dos conteúdos requisitados. A estratégia foi aplicada a um cenário de Redes Móveis Centradas na Informação, com o objetivo de prover descarregamento de dados. Resultados experimentais demonstram a capacidade de adaptação da estratégia proposta a diferentes cenários e evidenciam melhoras na taxa de acerto e no descarregamento de dados quando a estratégia é utilizada. Além disso, foi possível observar que quando a similaridade é baseada tanto na quantidade de conteúdos em comum quanto na frequência, as taxas de acerto e de descarregamento de dados são superiores a quando apenas um fator é utilizado.
Redução de dados em redes de sensores sem fio tolerantes a atrasos
Authors: Vasconcelos Israel , Aquino Andre
Published: May 2021

Este artigo apresenta um modelo de rede de sensores tolerante a atraso para aplicações de monitoramento ambiental onde uma solução de amostragem sensível aos dados é utilizada para melhorar a cobertura do fenômeno. O modelo proposto compreende uma aplicação de monitoramento de temperatura em regiões ﬂorestais, a implementação consiste em i. Simular regiões de interesse; ii. Distribuição dos nós sensores; iii. Realizar amostragem e processamento dos dados; iv. Reconstruir o fenômeno a partir das amostras; Os resultados obtidos apontaram que a abordagem sensível aos dados é capaz de reconstruir o fenômeno aproximadamente duas vezes mais próximo da realidade em relação às técnicas tradicionais, em todos os cenários avaliados.
Uma plataforma de IoT para integração de dispositivos baseada em nuvem com Apache Kafka
Authors: De Sousa Adriano B. , Neto José R. Torres , Filho Geraldo P. R. , Ueyama Jó
Published: May 2021

Bilhões de dispositivos conectados à Internet geram um grande volume de dados diversos diariamente, os quais servem como base para aplicações em escala global. A demanda crescente dessas aplicações geram alguns desaﬁos no ecossistema da Internet das Coisas, e.g. integração de dados e heterogeneidade de dispositivos. Soluções em plataformas baseadas na nuvem têm sido cada vez mais utilizadas para sanar tais desaﬁos. Entretanto, uma infraestrutura robusta para o armazenamento e o processamento de grandes quantidades de dados em tempo de execução é requerida. Este trabalho apresenta uma plataforma de IoT em nuvem capaz de lidar com a integração de grandes quantidades de dados e heterogeneidade dos dispositivos com base no Apache Kafka. As principais contribuições deste trabalho são: i) especiﬁcação, implantação e validação de uma plataforma IoT em nuvem e; ii) design e desenvolvimento de uma interface genérica baseada em webservice para abstração de detalhes a respeito da plataforma com os dispositivos. Com integração da plataforma e a interface desenvolvida foi possível obter resultados satisfatórios na padronização da comunicação e no ﬂuxo e armazenamento de dados de maneira conﬁável, oferecendo taxas de transferências rápidas em MB/s.
Aplicação de SDN no gerenciamento de perfis de usuário em dispositivos de rede
Authors: Costa Christiano , Alves Inácio , Maciel Jean , Albano Wellington
Published: May 2021

As Redes Deﬁnidas por Software (Software Deﬁned Network SDN) fazem a divisão do plano de controle e do plano de encaminhamento, permitindo que haja uma visão global da rede, proporcionando uma rede programável de alto nível. Isso pode ser muitoútil para permitir que o controle de acesso à rede seja gerenciado associando os ﬂuxos dos dispositivos a perﬁs de usuários. Este artigo propõe uma ferramenta de gerenciamento de perﬁs de usuário para a autorização de ﬂuxos de dispositivos utilizando redes deﬁnidas por software. Essa ferramenta foi implementada sobre o controlador OpenFlow POX. No artigo descrevemos os experimentos realizados e os resultados obtidos, que mostram a eﬁcácia e a facilidade de utilização do mecanismo.
Ein kritisches Transformationsverständnis zur Überwindung der vagen Ansätze zu Nachhaltigkeit und Transformation Kommentar zu Karl-Werner Brand
Authors: Brand Ulrich
Published: May 2021

Karl-Werner Brand skizziert zentrale Merkmale und Schwächen der Debatten zu Nachhaltigkeit beziehungsweise nachhaltiger Entwicklung und (Großer) Transformation, wie sie in den letzten Jahren geführt wurden. Vielen Punkten zustimmend, werden in diesem Kommentar einige seiner Argumente wie etwa die Einteilung der Forschung in problemlösungsorientierte und kritische Ansätze, die Annahme, dass der Begriff Transformation per se radikaler sei als jener der Nachhaltigkeit, die erhobene Forderung nach einer klaren Definition des Transformationsbegriffs oder die Ausblendung internationaler Dimensionen hinterfragt. Weiter wird argumentiert, dass sozial-ökologische Transformationen als Herausforderung für Wissenschaft und Praxis die strukturellen Ursachen der Nicht-Nachhaltigkeit berücksichtigen müssen, um die dominante „neue kritische Orthodoxie“ in Forschung und Praxis zu sozial-ökologischer Transformation zu überwinden.
Im politischen Vakuum?
Authors: Backhaus-Maul Holger , Hehl Lina , Speth Rudolph , Sydlik Tim , Wolfradt Louis
Published: May 2021

Organisiertes Engagement ist ein politisch und wissenschaftlich hochbedeutsames Thema. Besondere Bedeutung hat dieses Thema in einem Bundesland wie Sachsen, das bei aller regionalen Unterschiedlichkeit durch eine tiefgreifende gesellschaftlichen Polarisierung geprägt ist. Eine empirisch-qualitative Studie hat dieses organisierte Engagement auf Kommunal- und Landesebene eingehend untersucht. Im Beitrag werden ausgewählte Befunde präsentiert.
Engagementpolitik
Authors: Jakob Gisela
Published: May 2021

Engagementpolitik hat eine deutliche Aufwertung erfahren, ist auf allen föderalen Ebenen repräsentiert und hat neue Ansätze zur Engagementförderung ermöglicht. Allerdings lassen sich auch Tendenzen einer Vereinnahmung und Reglementierung von Zivilgesellschaft durch staatliche Maßnahmen beobachten, in deren Folge die Handlungsräume für bürgerschaftliches Engagement eingeschränkt werden.
Recht für die Soziale Arbeit
Authors: Beyer Thomas
Published: May 2021

In view of the growing importance of having solid knowledge of the law to practice social work, a range of custom-fit, specific introductory literature for practice-oriented training is more important than ever.

The second, updated edition of this book is intended to serve as a compendium for students of social work, but also to accompany their first steps into the profession. It explores important basic concepts, clarifies structures and makes contexts understandable.

This includes the defining characteristics of the system of social security in Germany and the actors and institutions that determine social work, as well as a discussion of the constitutional foundations of the welfare state and of organisations that provide social services, their legal forms of appearance and action, and their financing. Building on a basic section, it presents the legal framework conditions of central areas of activity in social work and essential legal questions related to the procedural practice of social work.
Die Verbundenheit des Kunden mit dem Konsumgüterunternehmen
Authors: Kohlepp Christina
Published: May 2021

What is a close customer relationship? When does it develop and can companies stimulate close customer relationships? A notion or concept of close customer relationships is still lacking in marketing research literature. Authors refer to an interaction- and an identification-based relationship, but do not specify their understanding of the interaction or identification which stimulates that relationship. Drawing on selected social psychological theories which focus on human interaction and identification, this dissertation examines whether and to what extent close interaction- and identification-based relationships between consumer goods companies and their customers are possible.
Rechtsfragen bei der Transplantation vaskularisierter komplexer Gewebe
Authors: Baudis Sarah
Published: May 2021

For some time now, the transplantations of organs and simple tissues have been a standard procedure in medicine. In contrast, the transplantations of faces, arms, penises and uteri represent new territory in medicine. It is therefore not surprising that the German legislation has not yet explicitly dealt with these so-called composite tissue allografts. It is unclear whether these tissues are to be classified as simple tissues, as organs or as a third group. The aim of this dissertation is to answer all open legal questions related to the transplantation process and to outline a corresponding legal framework de lege lata as well as de lege ferenda.
Siebzig Jahre Bundesverfassungsgericht in weltanschaulicher Schieflage
Authors: Czermak Gerhard
Published: May 2021

On the occasion of the 70th anniversary of the German Federal Constitutional Court in 2021, this volume examines the jurisprudence of the highest court on the relation of state and religion in the case groups of education, church labor law, church tax law, promotion of religion, and the principle of neutrality.

It is shown that, since the 1950s, the court has become biased in favor of religious groups and to the detriment of the legal method. The postulates of the neutral "state as the home of all citizens" and the "equal treatment of all" have often been violated. The causes of this development are discussed in detail and corrective proposals are formulated.
Bilateral Luxatio Erecta Humeri
Authors: Martinez-Romo Miguel , Lotfipour Shahram , McCoy C. Eric
Published: May 2021

Case Presentation: We describe a middle-aged male presenting to the emergency department with bilateral shoulder pain, holding both arms in abduction after trauma. Radiographs demonstrated a bilateral inferior dislocation of the glenohumeral joints consistent with luxatio erecta humeri.

Discussion: We review the clinical presentation of luxatio erecta and its complications. We also describe the characteristic presentation on radiographs. Our case illustrates the hallmark findings of luxatio erecta of an abducted humeral shaft parallel to the scapular spine.
Point-of-care Ultrasound in Early Diagnosis of Cardiomyopathy in a Child with Viral Myocarditis: A Case Report
Authors: Gupta Ayush , Eckenswiller Trevor
Published: May 2021

Introduction: Pediatric myocarditis is a commonly missed diagnosis in the pediatric emergency department (ED) with high morbidity and mortality. The presentation of cardiogenic shock secondary to myocarditis and septic shock can be difficult to differentiate during initial resuscitation, and incorrect treatment can lead to poor prognosis. Early diagnosis may provide a better prognosis for this life-threatening condition.

Case Report: We report a case of a five-year-old female who presented to the ED with non-specific symptoms of myocarditis. Rapid point-of-care ultrasound led to early diagnosis, correct management, and great prognosis for the patient.

Conclusion: Providers must maintain a high index of suspicion for cardiogenic shock in patients with nonspecific symptoms and fluid unresponsiveness. Point-of-care ultrasound can help in the identification of cardiac disorders and guide practitioners in their management plans.
Ultrasonographic Findings in Fat Embolism Syndrome
Authors: Yonezaki Shun , Nagasaki Kazuya , Kobayashi Hiroyuki
Published: May 2021

Case Presentation: A 93-year-old man living in a nursing home presented to our emergency department with altered mental status. Examination revealed hypotension and severe hypoxia. Chest radiograph showed infiltrates in the right upper lobe, and computed tomography of the abdomen and pelvis demonstrated a left femoral neck fracture. A point-of-care transthoracic echocardiogram (TTE) revealed an enlarged right ventricle, severe tricuspid regurgitation, and numerous white floating dots moving toward the right atrium from the inferior vena cava (IVC), leading to the diagnosis of fat embolism syndrome (FES).

Discussion: Although imaging studies can facilitate diagnosis, the diagnosis of FES is typically made by clinical history and presentation, making a swift diagnosis often difficult in those who are critically ill. Recent case reports have described that TTE can detect fat emboli, seen as flowing hyperechoic particles in IVC. This image demonstrates the utility of TTE to diagnose FES.
A Report of Two Cases: Unlearning Lactic Acidosis
Authors: Mohan Sanjay , Goldfarb David , Hoffman Robert
Published: May 2021

Introduction: The term “lactic acidosis” reinforces the misconception that lactate contributes to acidemia. Although it is common to discover an anion gap acidosis with a concomitant elevated lactate concentration, the two are not mutually dependent.

Case Report: Here we describe two patients exhibiting high lactate concentrations in the setting of metabolic alkalemia.

Conclusion: Lactate is not necessarily the direct cause of acid-base disturbances, and there is no fixed relationship between lactate and the anion gap or between lactate and pH. The term “metabolic acidosis with hyperlactatemia” is more specific than “lactic acidosis” and thus more appropriate.
Reversible Total Vision Loss Caused by Severe Metformin-associated Lactic Acidosis: A Case Report
Authors: Koons Andrew , Amaducci Alexandra , Katz Kenneth
Published: May 2021

Introduction: Metformin is a biguanide used to treat diabetes mellitus (DM). Metformin-associated lactic acidosis (MALA) carries a high mortality and can occur in patients with renal failure from drug bioaccumulation. Reversible vision loss is a highly unusual, rarely reported complication of MALA. We present a case of a patient whose serum metformin concentration was unusually high and associated with vision loss.

Case Report: A 60-year-old woman presented to an outside hospital emergency department with acute vision loss after being found at home confused, somnolent, and hypoglycemic, having last being seen normal two days prior. She reported vomiting and diarrhea during that time and a recently treated urinary tract infection. The visual loss resolved with continuous renal replacement therapy.

Conclusion: This novel case of a patient with Type II DM prescribed metformin and insulin who developed reversible vision loss while suffering from MALA highlights the potential for vision loss in association with MALA.
Neonatal Parotitis: A Case Report
Authors: Gupta Ayush , Kingdon Tyler , McKernan Andrew
Published: May 2021

Introduction: Acute suppurative parotitis is a rare finding in the neonate. It is commonly caused by Staphylococcus aureus, but other bacterial isolates may be emerging. It is a novel disease for this age group and requires unique management. Only 32 cases of neonatal suppurative parotitis have been described in the English-language literature over the last 35 years. Case Report: We describe a case of a 14-day-old male who presented to the pediatric emergency department with a 24-hour history of swelling and redness of the right cheek. On examining him, purulent material was seen inside his oral cavity. He was subsequently hospitalized with a diagnosis of neonatal suppurative parotitis and received five days of parenteral antibiotics with improvement in swelling and redness. He was discharged home with oral antibiotics. Conclusion: Although neonatal suppurative parotitis is rare, it should be suspected in newborns presenting with an erythematous pre-auricular mass with or without any predisposing factors. We describe a rare case of acute suppurative parotitis in a neonate and review the published literature.
Pediatric Innominate Artery Pseudoaneurysm Rupture in Vascular Ehlers-Danlos Syndrome: A Case Report
Authors: Vos Aimee , Burns Katharine
Published: May 2021

Introduction: Ehlers-Danlos syndrome is a well classified connective tissue disorder recognized by its features of hyperextensibility of joints and hyperelasticity of the skin. However, the rare vascular type (Ehlers-Danlos type IV) is more difficult to identify in the absence, rarity, or subtlety of the classical physical features. Patients presenting to the emergency department (ED) with acute complications of vascular Ehlers-Danlos syndrome may be critically ill, requiring accurate diagnosis and tailored management.

Case Report: This report details a case of spontaneous innominate artery pseudoaneurysm rupture in a pediatric patient with previously undiagnosed Ehlers-Danlos syndrome. Initial ED evaluation was followed by urgent operative intervention and subsequent genetic testing to confirm final diagnosis.

Conclusion: Due to its high morbidity and mortality, vascular type Ehlers-Danlos syndrome should be considered in the differential for otherwise unexplained spontaneous vascular injury.
Accidental Arthrotomy Causing Aseptic Monoarthritis Due to Agave Sap: A Case Report
Authors: Ontiveros Sam , Minns Alicia
Published: May 2021

Introduction: Aseptic inflammatory arthritis has been reported from thorns or cactus needles after inadvertent arthrotomy. Agave sap irritants may cause an aseptic inflammatory arthritis mimicking a septic joint.

Case Report: A 27-year-old male presented with left knee pain and swelling two hours after suffering an accidental stab wound to his left lateral knee by an agave plant spine. Synovial fluid white blood cell count was 92,730 mm3 with 75% neutrophils and no crystals. Surgical washout was remarkable for turbid fluid and no foreign body. Synovial fluid and blood cultures remained without growth. At two-week follow-up, the patient had recovered.

Conclusion: Penetrating injuries from agave thorns can cause an inflammatory arthritis that mimics septic arthritis.
Effect of Hydroalcoholic Extract of Ephedra major, Momordica charantia, and Resveratrol on Cytotoxicity and Caspase-3 Genes Expression Level in MCF-7 Breast Cancer Cell Line
Authors: Sabbagh Seyed Kazem , Ghodrati Ehsan , Hajibeiki Alireza , Mazaheri Mahta , Sarafraz Ardakani Mohammad Reza , Shaker Ardakani Zahra
Published: May 2021

Background: To increase the therapeutic effect of drugs to combat diseases, combination therapy with current chemical drugs and new medicines derived from medicinal plants is necessary. Objectives: The present work aimed to investigate the effect of hydroalcoholic extract of two medicinal plants, Ephedra major and Momordica cacharantia (Carla), and resveratrol drug on cell viability and expression levels of caspase-3 gene in MCF-7 cell line. Methods: In this experimental study, the hydroalcoholic extraction of tested plants was done with a Soxhlet extractor. The MTT assay and real-time PCR were used to determine cell toxicity and caspase-3 gene expression levels, respectively. Results: The highest and lowest cytotoxic effects of plant extracts and resveratrol were observed at concentrations of 500 and 150 µg/mL, respectively. The highest level of the caspase-3 gene expression was observed after 72 h of incubation by different concentrations of plant extracts and resveratrol. Conclusions: It can be concluded that both plant extracts could influence cell viability in MCF-7 cells via the increase of cell toxicity and expression of caspase-3 gene. Thus, these species could be used in the pharmaceutical industry.
Challenges of communication in the times of coronavirus
Authors: Boranijašević Marija
Published: May 2021

The subject of research in this paper is the analysis of the communication process which is by all means specific and different in the times of coronavirus. The pandemic caused by Covid-19 virus has appeared suddenly, spread astronomically fast, left enormous consequences and does not abate, affecting all the spheres of human life. The imposed changes of the life style have led to huge changes in human communication practice, the consequence of which is the social alienation which is omnipresent. The author researches to which extent the social isolation affects the human communication practice and whether people turn to virtual communication in the absence of direct human contact. The goal of this research is to determine in which way the use of modern technology and new media, primarily the Internet and social networks, affects the sense of loneliness which inevitably appears during the pandemic and whether the use of modern technology helps to mitigate this sense of loneliness, if not eliminate it.
Error analysis: A way to learn mathematics more efficiently
Authors: Glovňová Veronika
Published: May 2021

Errors and overcoming failures are natural elements of the education process of all students. Our society tends not to look at them positively - teachers often try to avoid errors as well as they lead students to avoid them. They do not tend to use errors as a learning tool full of opportunities to better understanding. In this study we present the results of the observations of twelve lessons of mathematics, showing their common features with a special focus on errors. The core of the text also offers a detailed analysis of two lessons, where traditional teaching approach prevailed, and one lesson, mostly but not completely, conducted in a constructivist way. It includes beliefs and mindsets of those three teachers, showing their direct or indirect influence on their teaching. We also discuss their approach to math problems as well as the possible influence of their teaching on students. The paper stresses a discrepancy between beliefs of teachers related to errors and the reality in their practice.
Strategic planning research through fifty years of long range planning: A bibliometric overview
Authors: Baier-Fuentes Hugo , Merigó José , Miranda Luis , Martínez-López Francisco
Published: May 2021

Long Range Planning (LRP) is the first journal focused on strategic planning. It was created in 1968 by the Long Range Planning Society, and it celebrated its 50 th anniversary in 2018. This event led to the presentation of a complete bibliometric study aimed at identifying the most significant results that occurred in the journal during this period. For this purpose, bibliometric data were collected from the Web of Science Core Collection database, and two bibliometric approaches were used to analyze the journal's publications: a performance analysis and a graphical mapping of the literature. The first of these uses a wide range of productivity and influence indicators that include the number of publications and citations, the h-index, and citations by paper, among others. The second approach uses the VOSviewer software to deliver a graphical view of the various intellectual connections within LRP. The results of both bibliometric approaches are consistent and confirm LRP as a leading journal in strategic planning and management, with increasing participation of authors and universities from countries around the world.
Leadership style and employee readiness: Basic factors of leadership efficiency
Authors: Rodić Marijana , Marić Slobodan
Published: May 2021

The scope of this study is based on the Situational Leadership Theory according to the model created by Hersey and Blanchard, predominantly defined by two research sub-fields: leadership style and readiness of employees. This model distinguishes four different leadership styles, while the subject area of readiness of employees comprises two components: readiness of employees based on the competency component and readiness of employees based on a psychological (motivational) component. The subject matter of the study is to identify leadership style as a new variable which will be utilized for determining the interdependence with leadership efficiency levels and readiness of employees. Leadership efficiency is determined by the degree of compatibility between the dominant style of leadership and the level of readiness of employees. In addition to the main objective of the research, aimed at determining leadership efficiency, significant research findings come as a result of specific objectives. That is impact of the dominant leadership style on readiness of employees and leadership results, based on each specific component. The sample will be a random sample from a finite population of units, with repeated sampling and known probability sampling. A sample of size n=100, with a proportion of 0.10, is based on a list of top 100 biggest companies in the Republic of Serbia in 2019. The application of Principal Component Analysis aims to identify new variables in the form of regression coefficient results, while the application of the hierarchical regression model will help determine the impact of each leadership style on readiness of employees. The study findings confirm the basic hypotheses of the aforementioned model, with regard to the results of leadership efficiency, as well as its impact of each leadership style on readiness of employees.
Analysis of Lift and Drag on a Surface-Piercing Foil
Authors: Kuhn John C. , Scragg Carl A.
Published: May 2021

Hydrofoils operating at shallow depths ( e.g. keels and rudders) will be affected by the interactions between the lifting surfaces and the free surface. This problem is approached computationally and experimentally by examining the simple case of a surface-piercing hydrofoil operating at steady forward speeds and small angles of attack. It is shown that there are two contributions to the lift and drag on the foil, one due to the vorticity shed into the wake and another due to the port/starboard asymmetry of the radiated wave field.

The mathematical problem is specified as a linearized boundary-value problem to be solved numerically. The two contributions to the lift and drag on the foil are determined independently from far-field momentum integrations. Calculations of the lift and drag on surface-piercing foils with variations in aspect ratio and heel angle are compared to experimental results. Comparisons of the predicted and measured radiated wave fields generated by the foils are also presented. It is found that the efficiency of the foil is reduced by the presence of the free surface and that the use of simple reflection-plane models can lead to significant errors.
Towards a Rational Upwind Sail Force Model for VPPs
Authors: Euerle Steven E. , Greeley David S.
Published: May 2021

A method for generating upwind sail force coefficients for arbitrary fore-and-aft rigs is presented, requiring a minimum amount of empirical data. Example calculations for an IACC boat showed that the resulting sail force model was quite realistic, and did not require any "tuning" of coefficients. Further developments of this technique are suggested, as well as the extension to off­wind sailing.
Elements of Resistance of IACC Yachts
Authors: Milgram Jerome H. , Frimm Fernando C.
Published: May 2021

Resistances due to hull friction, appendage friction, wavemaking, heel and side force, and sea waves are considered. Comparative values of each of these resis­tance components for four boats, including one with two different sets of appendages, are shown. Most of the resistance components are accurately determined by a combination of theory, numerical computation or model testing. An exception is the resistance due to sea waves for which nonlinear effects not accounted for in present theories appear to be significant. Some de­sign features which increase resistance have associated speed-increasing effects. An example is increasing the vessel beam which increases wetted surface, and there­fore the frictional resistance, but has an associated in­crease in potential sail power. This demonstrates the necessity of evaluating the entire system with a good velocity prediction program rather than using an eval­uation based on a few resistance components.
Do Private Schools in Australia Produce More Active Citizens?
Authors: Saha Lawrence J.
Published: May 2021

The focus of this paper is whether type of Australian school attended makes a difference in student engagement in political and civic culture. Recently private schools have been said to “undermine cohesion” in Australian society. Similarly, it was argued over two decade
ago that Australian private schools have skimmed the elite students from the government sector and now “impart to their pupils values and preferences of the culture from which they are drawn”, namely the dominant culture. Using data from the Youth Electoral Study (YES) survey,
this analysis examines whether Australian students in government, Catholic and Independent schools differ in six political domains: voting commitment, positive attitude toward voting, political knowledge, political activism, political trust and civic volunteer behaviour. At the bivariate level,
students in private schools generally show higher levels of political engagement compared to students in government schools in all domains. However, when family and school variables are controlled, the differences between these students in voting commitment, political knowledge and volunteer
behaviour disappear. However students in Catholic schools show significantly higher levels in positive attitude toward voting and political activism. The effects of Independent schools disappear for five political domains but a significantly high level of political trust remains. Explanations
for these patterns of outcomes are put forward, and directions for future research are explored.
Effect of surface tension on late-time growth of high-Reynolds-number Rayleigh-Taylor instability
Authors: Huang Hao-Wei , Liang Hong , Xu Jiang-Rong ,   Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China
Published: May 2021

In this paper, we numerically investigate the late-time growth of high-Reynolds-number single-mode Rayleigh-Taylor instability in a long pipe by using an advanced phase-field lattice Boltzmann multiphase method. We mainly analyze the influence of surface tension on interfacial dynamic behavior and the development of the bubble front and spike front. The numerical experiments indicate that increasing surface tension can significantly reduce the complexity of formed interfacial structure and also prevents the breakup of phase interfaces. The interface patterns in the instability process cannot always preserve the symmetric property under the extremely small surface tension, but they do maintain the symmetries with respect to the middle line as the surface tension is increased. We also report that the bubble amplitude first increases then decreases with the surface tension. There are no obvious differences between the curves of spike amplitudes for low surface tensions. However, when the surface tension increases to a critical value, it can slow down the spike growth significantly. When the surface tension is lower than the critical value, the development of the high-Reynolds-number Rayleigh-Taylor instability can be divided into four different stages, i.e. the linear growth, saturated velocity growth, reacceleration, and chaotic mixing. The bubble and spike velocities at the second stage show good agreement with those from the modified potential flow theory that takes the surface tension effect into account. After that, the bubble front and spike front are accelerated due to the formation of Kelvin-Helmholtz vortices in the interfacial region. At the late time, the bubble velocity and spike velocity become unstable and slightly fluctuate over time. To determine the nature of the late-time growth, we also measure the bubble and spike normalized accelerations at various interfacial tensions and Atwood numbers. It is found that both the spike and bubble growth rates first increase then decrease with the surface tension in general. Finally, we deduce a theoretical formula for the critical surface tension, below which the Rayleigh-Taylor instability takes place and above which tension it does not occur. It is shown that the critical surface tension increases with the Atwood number and also the numerical predictions by the lattice Boltzmann method are also in accord well with the theoretical results.
Античная ойкумена и ее загадки, "Природа"
Authors: Черных Е.Н.
Published: May 2021

В представлении древнегреческих мыслителей ойкумена состояла из трех материков — Европы, Азии и Ливии. В центре находилась, конечно же, Эллада. Свое понимание устройства окружающего мира эллинские ученые выражали преимущественно в описаниях, а карты по этим описаниям создавались уже другими людьми и много позже. Остается загадкой, почему все материки получили женские имена, кем на самом деле были те знаменитые женщины и чем они заслужили такую высокую честь. В своих многочисленных трудах греки описывали Рифейские горы, разделяющие Европу и Азию, а также загадочную страну Гиперборею, лежащую на севере ойкумены. Существуют ли эти географические объекты в действительности Если да, то где они находятся и как называются сегодня
Variation in the Proximate Composition, Amino Acids Content and Fatty Acids of Thai Pangus (Pangasianodonhypophthalmus) Fish Depending on Size
Authors: Salman Md. , Suraiya Sharmin , Das Pranta , Islam Md. Aminur , Haq Monjurul
Published: May 2021

The nutritional characteristics such as proximate composition, amino acids, and fatty acids properties of fish depend on the size of fish. Determination of the nutritional parameters of Thai pangus muscle depending on five different sizes, viz., 0.5 kg, 1.0 kg, 1.5 kg, 2.0 kg, and 2.5 kg showed that the moisture content was decreased whereas the protein content was increased with the increment of fish weight. The protein content was the highest 16.60% in 2.5 kg size fish and the lowest content 14.75% was in 0.5 kg size fish. The lipid content was found to increase significantly (P≤0.05) with the increment of fish weight. There were eight essential and nine non-essential amino acids available and the contents were found to increase with the increment of fish weight. The content of essential amino acids was the highest (14.43 g/100 g fish muscle) in 2.5 kg size fish while the lowest (7.79 g/100 g fish muscle) in 0.5 kg size fish. Total 13 fatty acids were detected in fish oil among which oleic acid content was the highest (44.55% to 47.10%) followed by palmitic acid (25.78% to 36.39%), however, the ω-3 polyunsaturated fatty acids contentwere very poor. The saturated fatty acids content were found to increase whereas the polyunsaturated fatty acids content were found to decrease with increasing the size of fish. So, the findings of this present study reveal that the muscles of Thai Pangus fish are considered as highly nutritive and healthy.