bluuebunny/crossref_metadata_2025 huggingface dataset:
Associação entre o excesso de peso e de gordura corporal nas crianças com sobrepeso/obesidade materno
Authors: Filgueiras Mariana de Santis , De Albuquerque Fernanda Martins , Castro Ana Paula Pereira , Rocha Naruna Pereira , Milagres Luana Cupertino , De Novaes Juliana Farias
Published: March 2021

A obesidade infantil é um problema de saúde pública global, sendo que no Brasil sua prevalência é de 14,3% em crianças de 5 a 9 anos de idade. O ambiente familiar exerce um papel fundamental na gênese da obesidade, sendo responsável pela formação de hábitos alimentares e de estilo de vida. Tendo em vista essa relação, é importante avaliar o estado nutricional dos pais, sobretudo das mães, uma vez que estas tendem a influenciar a formação destes hábitos. Avaliar a associação entre a presença de excesso de peso/gordura corporal em crianças e o estado nutricional materno. Estudo transversal com 292 crianças de 8 e 9 anos matriculadas em escolas públicas e privadas na zona urbana do município de Viçosa-MG. Foram aferidos peso e estatura para o cálculo do Índice de Massa Corporal por Idade (IMC/I) de acordo com a Organização Mundial da Saúde (OMS, 2007). A gordura corporal (%GC) foi obtida pela bioimpedância bipolar (Tanita® Modelo Ironman BC 553) classificada segundo Lohman (1992). Para avaliar o estado nutricional materno, foram aferidas as medidas de peso e estatura para o cálculo do IMC, utilizando os pontos de corte da OMS (2000). Crianças e mães com sobrepeso e obesidade foram classificadas como excesso de peso. As análises estatísticas foram realizadas no software SPSS versão 20, sendo considerado o nível de significância de 5%. Este estudo foi aprovado pelo Comitê de Ética em Pesquisa com Seres Humanos da Universidade Federal de Viçosa. As prevalências de crianças com excesso de peso e de gordura corporal foram de 32,8% e 49,7%, respectivamente, e 57,5% das mães apresentaram excesso de peso. As prevalências de crianças com excesso de peso e de gordura corporal foram maiores entre aquelas com mães com excesso de peso em comparação às mães sem excesso peso (42,9% versus 18,5%, 55,4% versus 42,7%, p<0,05). Foram observadas correlações significantes entre os dados das crianças (IMC, escore-Z de IMC/I e %GC) com o IMC materno (IMC: 0,351; p<0,001; escore-Z de IMC/I: 0,338; p<0,001; %GC: 0,317, p<0,001). As prevalências de excesso de peso e de gordura corporal em crianças estiveram associadas ao excesso de peso materno. Resultados como esses ressaltam a importância de elaborar estratégias educativas relacionadas à saúde para crianças juntamente aos seus pais, considerando sua importância na formação de hábitos alimentares e de estilo de vida, de modo a prevenir o surgimento de complicações cardiometabólicas na infância e na fase adulta.
Frequência de consumo de alimentos promotores do excesso de peso no primeiro ano de vida
Authors: Silva Mariane Alves , Fonsêca Poliana Cristina de Almeida , Vieira Sarah Aparecida , De Carvalho Carolina Abreu , De Novaes Juliana Farias , Franceschini Sylvia do Carmo Castro
Published: March 2021

O excesso de peso é considerado atualmente um problema de saúde pública. De acordo com dados da Pesquisa de Orçamentos Familiares- POF (2008-2009) o número de crianças acima do peso dobrou nos últimos anos, passando de 15% para 34,8%. O consumo alimentar está entre as causas do excesso de peso, passível de modificação. De acordo com Carrazzoni (2015), os alimentos que a criança tem contato na infância podem ser determinantes do seu estado nutricional. Avaliar a frequência de consumo de alimentos promotores do excesso de peso por crianças menores de um ano de idade. Estudo longitudinal com 116 crianças, acompanhadas no primeiro ano de vida na Policlínica Municipal de Viçosa. No 6º e 9º mês as crianças foram atendidas, sendo feitas orientações nutricionais às mães e entregue folders contendo informações sobre alimentação complementar e alimentos que deveriam ser evitados no primeiro ano de vida. Em outra consulta, no 12º mês de vida, foi aplicado o Questionário de Frequência Alimentar (QFA), a fim de se verificar o consumo dos alimentos promotores do excesso de peso pelas crianças. A frequência de consumo foi categorizada em pelo menos uma vez na semana, quinzenalmente, raramente/nunca. Foram aferidos o peso e o comprimento, e calculado o IMC. Para avaliar associação do escore-z de IMC com a frequência de consumo alimentar foi realizado o teste Kruskal-Wallis. As análises estatísticas foram realizadas no software Stata 10.0, com nível de significância de 5%. Todas as mães relataram o consumo de pelo menos um alimento promotor do excesso de peso pelas crianças. O maior consumo foi de Danoninho (54,8%), pelo menos uma vez na semana. Destaca-se que, 72,8% das mães relataram que seus filhos nunca consumiram achocolatado e 53,1% das crianças nunca beberam refrigerante. Resultados satisfatórios foram observados para o consumo de biscoito recheado, chocolate e salgadinho, no qual 84,2%, 96,4% e 79,5% referiram raramente ou nunca terem consumido esses alimentos, respectivamente. Maiores valores de IMC se associaram positivamente com a ingestão de Danoninho em pelo menos uma vez na semana (p=0,018). Evidencia-se a importância de orientações nutricionais com apresentação de materiais educativos, uma vez que o consumo de alimentos promotores da obesidade foi inferior à outros estudos nacionais. Além disso, destaca-se que a maior parte das crianças não consumiam alimentos industrializados. Nesse contexto, o acesso das mães à informação é fundamental na tomada de decisões sobre os alimentos que devem ou não ser ofertados à criança.
A relação dos fatores decorrentes do envelhecimento na Biomecânica em indivíduos adultos e idosos
Authors: Souza E. S. , Bhering N. L. B. , Neto A. , Germary T. , Morais S. O. , Martinho K.
Published: March 2021

A biomecânica aborda fatores que isoladamente determinam quais os músculos são recrutados para realização de um determinado movimento. A postura é considerada a base dos movimentos, e o controle contra a tração da gravidade exigem a plena atuação da musculatura. As alterações na fisiologia do idoso afeta o equilibrio, a força e a visão, alterando a sua marcha e levando o individuo a queda. Fatores como idade, sexo, doenças, uso de medicamentos, prejuízo da capacidade funcional e fraqueza muscular têm sido apontados pela literatura como predisponentes de quedas em maior grau. Este estudo tem como objetivo analisar dados presente na base de dados pública DATASUS/TabNet, procurando identificar os principais fatores e modificações na biomecânica que levaram o risco de queda no período de janeiro 2008 a maio de 2016 no estado de Minas Gerais. Por meio da análise de correspondência por variável canônica, os dados obtidos estão sendo analisados entre as faixas etárias de: 20-39, 40-59, 60-69 70-79 e de 80+. A população total do estudo presente na base de dados foi de 13.661.545. Os fatores escolhidos estão em conformidade com o CID 10: W01 - Queda no mesmo nível, escorregão, tropeção ou passos em falsos (traspés). Estes foram relacionados com o índice de morbidade hospitalar do SUS por causas externas. Na faixa etária de 20-29 com a população de 3.485.826 foi apontado um índice de 11.045 internações, isto é, uma proporção de 0,31% de quedas. Na faixa etária de 30 a 39 a população de 3.053.332 e tendo 10.413 internações, a proporção é de 0,34% de quedas. Na faixa etária de 40 a 49 a população é de 2.703.589 com 9.904 internações, proporção de 0,36% de quedas. Na faixa etária de 50 a 59 a população é de 2.081.174 com 9.610 internações, proporção de 0,46% de quedas. Na faixa etária de 60 a 69 a população é de 1.272.322 com 6.826 internações, proporção de 0,53% de quedas. Na faixa etária de 70 a 79 a população é de 731.610 e com 5.976 internações, uma proporção de 0,81% de quedas. Já na faixa etária acima de 80 anos a população é de 333.692 com 5.975 internações uma proporção de 1,7% de quedas. As quedas estão associadas ao equilíbrio e a marcha, sendo que o envelhecimento afeta claramente o índice de hospitalização por motivo de quedas. Estudos envolvendo análises das variáveis biomecânicas e da atividade muscular em idosos que sofrem uma queda durante a marcha, são indispensáveis para o entendimento da relação entre estes fatores ao longo do tempo de vida. Portanto, é necessária uma investigação profunda sobre as modificações e assim auxiliar a elaboração de políticas públicas e programas de reabilitação especifica para prevenir ou mitigar as quedas na população idosa.
Associação do número diário de refeições com parâmetros antropométricos em crianças
Authors: De Albuquerque Fernanda Martins , Filgueiras Mariana de Santis , Milagres Luana Cupertino , Rocha Naruna Pereira , Castro Ana Paula Pereira , De Novaes Juliana Farias
Published: March 2021

Com a rápida mudança do padrão alimentar e do estilo de vida decorrente do processo de transição nutricional, observa-se o aumento da prevalência de excesso de peso na população infantil em diversas partes do mundo, com repercussões sobre a situação da saúde e qualidade de vida das crianças. A fase escolar é caracterizada por intensas atividades e este ritmo muitas vezes prejudica o fracionamento das refeições durante o dia. A omissão de refeições é prejudicial uma vez que o maior fracionamento destas proporciona uma maior saciedade e aumenta o gasto energético auxiliando no controle do peso corporal. Avaliar a associação do número diário de refeições com parâmetros antropométricos em crianças de Viçosa-MG. Trata-se de um estudo transversal realizado com 378 crianças de ambos os sexos com idade de 8 e 9 anos, matriculadas em escolas públicas e privadas da zona urbana de Viçosa-MG. Foram aferidos peso e estatura e essas medidas foram utilizadas para o cálculo do Índice de Massa Corporal (IMC). O perímetro da cintura (PC) foi aferido no ponto médio entre a crista ilíaca e a última costela. O número médio de refeições diárias foi obtido somando-se o número de refeições realizadas em três dias não consecutivos por meio da aplicação do recordatório alimentar de 24 horas e calculando-se a média final dos três dias. A análise estatística foi realizada no software SPSS versão 20, sendo considerado o nível de significância estatística de 5%. Este estudo foi aprovado pelo Comitê de Ética em Pesquisa com Seres Humanos da Universidade Federal de Viçosa. Crianças que realizavam três ou menos refeições por dia tiveram maiores medianas de IMC (23,4 kg/m²) e PC (69,1 cm) em relação àquelas que realizavam mais de três refeições diárias (69,1 kg/m² e 57,5 cm, respectivamente) (p<0,05). Verifica-se que crianças com um menor fracionamento das refeições apresentaram maiores valores de IMC e PC. Esse resultado sugere haver uma associação do número de refeições realizadas por dia com o excesso de peso infantil. Ações de reeducação alimentar e nutricional devem ser realizadas de forma precoce para prevenção da obesidade e de comorbidades associadas. Além dos serviços de saúde, as escolas configuram-se como um ambiente propício para o desenvolvimento destas ações para a promoção de hábitos alimentares saudáveis.
The Perils and Pitfalls of Esophageal Dysmotility in Idiopathic Pulmonary Fibrosis
Authors: Cheah Ramsah , Chirnaksorn Supphamat , Abdelrahim Ahmed H. , Horgan Laura , Capstick Toby , Casey John , Peckham Daniel , Boland Alison , Sutherland Timothy J. T. , Beirne Paul , Lee Augustine S. , DeVault Kenneth R. , Houghton Lesley A.
Published: March 2021

INTRODUCTION:

Gastroesophageal reflux plays a significant role in idiopathic pulmonary fibrosis (IPF). Given the morbidity and mortality associated with IPF, understanding the mechanisms responsible for reflux is essential if patients are to receive optimal treatment and management, especially given the lack of clear benefit of antireflux therapies. Our aim was to understand the inter-relationships between esophageal motility, lung mechanics and reflux (particularly proximal reflux—a prerequisite of aspiration), and pulmonary function in patients with IPF.

METHODS:

We prospectively recruited 35 patients with IPF (aged 53–75 years; 27 men) who underwent high-resolution impedance manometry and 24-hour pH-impedance, together with pulmonary function assessment.

RESULTS:

Twenty-two patients (63%) exhibited dysmotility, 16 (73%) exhibited ineffective esophageal motility (IEM), and 6 (27%) exhibited esophagogastric junction outflow obstruction. Patients with IEM had more severe pulmonary disease (% forced vital capacity: P = 0.032) and more proximal reflux (P = 0.074) than patients with normal motility. In patients with IEM, intrathoracic pressure inversely correlated with the number of proximal events (r = −0.429; P = 0.098). Surprisingly, inspiratory lower esophageal sphincter pressure (LESP) positively correlated with the percentage of reflux events reaching the proximal esophagus (r = 0.583; P = 0.018), whereas in patients with normal motility, it inversely correlated with the bolus exposure time (r = −0.478; P = 0.098) and number of proximal events (r = −0.542; P = 0.056). % forced vital capacity in patients with IEM inversely correlated with the percentage of reflux events reaching the proximal esophagus (r = −0.520; P = 0.039) and inspiratory LESP (r = −0.477; P = 0.062) and positively correlated with intrathoracic pressure (r = 0.633; P = 0.008).

DISCUSSION:

We have shown that pulmonary function is worse in patients with IEM which is associated with more proximal reflux events, the latter correlating with lower intrathoracic pressures and higher LESPs.
Integrative Effects and Vagal Mechanisms of Transcutaneous Electrical Acustimulation on Gastroesophageal Motility in Patients With Gastroesophageal Reflux Disease
Authors: Zhang Bo , Hu Yedong , Shi Xiaodan , Li Wenna , Zeng Xin , Liu Fei , Chen Jiande D.Z. , Xie Wei-Fen
Published: March 2021

INTRODUCTION:

Impaired esophageal and gastric motilities are known to contribute to symptoms of gastroesophageal reflux disease (GERD). However, there is a lack of GERD therapy, targeting both gastric and esophageal functions. This study was designed to investigate the effects of transcutaneous electrical acustimulation (TEA) on symptoms of GERD and gastroesophageal functions and possible mechanisms in patients with GERD.

METHODS:

Thirty patients with GERD with ineffective esophageal motility were equally divided and randomized into a 4-week sham-TEA or 4-week TEA treatment. The GERD questionnaire (GerdQ), GERD health-related quality-of-life questionnaire, high-resolution esophageal manometry, a nutrient drink test, the electrogastrogram, and ECG were performed to assess the severity of reflux symptoms, low esophageal sphincter (LES) pressure, distal contractile integral (DCI), gastric accommodation, gastric slow waves (GSW), and autonomic functions, respectively.

RESULTS:

Compared with sham-TEA, the 4-week TEA treatment significantly decreased the GerdQ score (P = 0.011) and GERD health-related quality of life (P = 0.028) and improved nutrient drink–induced fullness (P < 0.001) and belching (P < 0.001) in patients with GERD. Although only acute TEA significantly enhanced LES pressure (P < 0.05), both acute and chronic TEA remarkedly increased DCI (P < 0.05) and reduced the incidence of ineffective esophageal contractions during wet swallows (P = 0.02). In addition, chronic TEA significantly increased gastric accommodation and the percentage of postprandial normal GSW compared with sham-TEA and baseline. Concurrently, TEA-enhanced vagal activity (P = 0.02) and the vagal activity positively correlated with LES pressure (r = 0.528; P = 0.003) and DCI (r = 0.522; P = 0.003).

DISCUSSION:

The TEA treatment performed in this study improves reflux-related symptoms, increases DCI, reduces the incidence of ineffective esophageal contractions during wet swallows, and improves gastric accommodation and slow waves. The improvement in GERD symptoms might be attributed to the integrative effects of TEA on these gastroesophageal functions mediated via the vagal mechanism.
Mixing Suspensions in Tall Vessels with a Draught Tube
Authors: Brož J. , Rieger F.
Published: March 2021

A tall vessel with a telescopic draught tube is proposed for mixing suspensions. The paper presents the relations for calculating the agitator power consumption and the speed necessary to keep a particle in suspension.
Self Heating of an Atomic Force Microscope
Authors: Kučera O.
Published: March 2021

Atomic force microscopy (AFM) is a sensitive technique susceptible to unwanted influences, such as thermal noise, vibrational noise, etc. Although, tools that protect AFM against external noise have been developed and are widely used, there are still many sources of inherent noise. One of them is self-heating of the apparatus. This paper deals with self-heating of the AFM using an optical lever. This phenomenon is shown to be substantial in particular after activation of the microscope. The influence on the intrinsic contact noise of AFM’s is also examined.
Gearbox Condition Monitoring Using Advanced Classifiers
Authors: Večeř P. , Kreidl M. , Šmíd R.
Published: March 2021

New efficient and reliable methods for gearbox diagnostics are needed in automotive industry because of growing demand for production quality. This paper presents the application of two different classifiers for gearbox diagnostics – Kohonen Neural Networks and the Adaptive-Network-based Fuzzy Interface System (ANFIS). Two different practical applications are presented. In the first application, the tested gearboxes are separated into two classes according to their condition indicators. In the second example, ANFIS is applied to label the tested gearboxes with a Quality Index according to the condition indicators. In both applications, the condition indicators were computed from the vibration of the gearbox housing.
Ultracapacitors Utilization for Automotive Applications
Authors: Pfof Z. , Vaculík P.
Published: March 2021

This paper describes the basic properties of ultracapacitors and a converter for ultracapacitors with application zero-voltage switching (ZVS). Because of the very high efficiency of the ultracapacitor, the efficiency of the converter for ultracapacitors also has to be high; otherwise, the converter reduces efficiency of the whole drive unit. Further, the paper describes the drive unit concept for the CityEl electric vehicle, with the use of ultracapacitors in cooperation with a fuel cell. This co-operation with ultracapacitors is useful for the supply unit as a fuel cell, which cannot deliver peak power in dynamic conditions while maintaining its nominal efficiency. However, this poses no problems for ultracapacitors.There is also a description of the basic principles of soft switching using zero-voltage and zero-current switching together with a comparison of the power losses between hard and soft switching.
Flock Growth Kinetics for Flocculation in an Agitated Tank
Authors: Šulc R. , Svačina O.
Published: March 2021

Flock growth kinetics was investigated in baffled tank agitated by a Rushton turbine at mixing intensity 40 W/m3 and kaolin concentration 0.44 g/l. The tests were carried out with a model wastewater (a suspension of tap water and kaolin). The model wastewater was flocculated with organic Sokoflok 56 A flocculant (solution 0.1 % wt.). The flock size and flock shape were investigated by image analysis. A simple semiempirical generalized correlation for flock growth kinetics was proposed, and was used for data treatment. The flock shape was characterized by fractal dimension Df2. Using the statistical hypothesis test, the fractal dimension was found to be independent of flocculation time, and the value Df2 = 1.442 ± 0.125 was determined as the average value for the given conditions.
Injection and Combustion of RME with Water Emulsions in a Diesel Engine
Authors: Cisek J.
Published: March 2021

This paper presents ways of using the fully-digitised triggerable AVL VideoScope 513D video system for analysing the injection and combustion inside a diesel engine cylinder fuelled by RME with water emulsions.The research objects were: standard diesel fuel, rapeseed methyl ester (RME) and RME – water emulsions. With the aid of a helical flow reactor, stable emulsions with the water fraction up to 30 % weight were obtained, using an additive to prevent the water from separating out of the emulsion.An investigation was made of the effect of the emulsions on exhaust gas emissions (NOX, CO and HC), particulate matter emissions, smoke and the fuel consumption of a one-cylinder HD diesel engine with direct injection. Additionally, the maximum cylinder pressure rise was calculated from the indicator diagram. The test engine was operated at a constant speed of 1 600 rpm and 4 bar BMEP load conditions. The fuel injection and combustion processes were observed and analysed using endoscopes and a digital camera. The temperature distribution in the combustion chamber was analysed quantitatively using the two-colour method. The injection and combustion phenomena were described and compared.A way to reduce NOX formation in the combustion chamber of diesel engines by adding water in the combustion zone was presented. Evaporating water efficiently lowers the peak flame temperature and the temperature in the post-flame zone. For diesel engines, there is an exponential relationship between NOX emissions and peak combustion temperatures. The energy needed to vaporize the water results in lower peak temperatures of the combusted gases, with a consequent reduction in nitrogen oxide formation. The experimental results show up to 50 % NOX emission reduction with the use of 30% water in an RME emulsion, with unchanged engine performance.
Superconformal Calogero Models as a Gauged Matrix Mechanics
Authors: Fedoruk S.
Published: March 2021

We present basics of the gauged superfield approach to constructing the N-superconformal multi-particle Calogero-type systems developed in arXiv:0812.4276, arXiv:0905.4951 and arXiv:0912.3508. This approach is illustrated by multi-particlesystems possessing SU(1, 1|1) and D(2, 1; α) supersymmetries, as well as by the model of new N = 4 superconformal quantum mechanics.
Lorentz and SU(3) Groups Derived from Cubic Quark Algebra
Authors: Kerner R.
Published: March 2021

We show how Lorentz and SU(3) groups can be derived from the covariance principle conserving a Z3-graded three-form on a Z3-graded cubic algebra representing quarks endowed with non-standard commutation laws. This construction suggests that the geometry of space-time can be considered as a manifestation of symmetries of fundamental matter fields.
Asymptotic Power Series of Field Correlators
Authors: Caprini I. , Fischer J. , Vrkoč I.
Published: March 2021

We address the problem of ambiguity of a function determined by an asymptotic perturbation expansion. Using a modified form of theWatson lemma recently proved elsewhere, we discuss a large class of functions determined by the same asymptotic power expansion and represented by various forms of integrals of the Laplace-Borel type along a general contour in the Borel complex plane. Some remarks on possible applications in QCD are made.
M2-Branes in N = 3 Harmonic Superspace
Authors: Ivanov E.
Published: March 2021

We give a brief account of the recently proposed N = 3 superfield formulation of the N = 6, 3D superconformal theory of Aharony et al (ABJM) describing a low-energy limit of the system of multiple M2-branes on the AdS4×S7/Zk background. This formulation is given in harmonic N = 3 superspace and reveals a number of surprising new features. In particular, the sextic scalar potential of ABJM arises at the on-shell component level as the result of eliminating appropriate auxiliary fields, while there is no explicit superpotential at the off-shell superfield level.
Maxwell-Chern-Simons Models: Their Symmetries, Exact Solutions and Non-relativistic Limits
Authors: Niederle J. , Nikitin A. G. , Kuriksha O.
Published: March 2021

Two Maxwell-Chern-Simons (MCS) models in the (1 + 3)-dimensional space-space are discussed and families of their exact solutions are found. In contrast to the Carroll-Field-Jackiw (CFE) model [2] these systems are relativistically invariant and include the CFJ model as a particular sector.Using the InNonNu-Wigner contraction a Galilei-invariant non-relativistic limit of the systems is found, which makes possible to find a Galilean formulation of the CFJ model.
Conductivity Measurements of Silverpastes
Authors: Dirix M. , Koch O.
Published: March 2021

The development of three-dimensional printed circuit boards requires research on new materials which can easily be deformed. Conducting pastes are well suited for deformation even after they are applied to the dielectric carrier. This paper deals with measurements of the electrical conductivity of these conducting pastes. Two different conductivity measurement techniques are explained and carried out. The resulting measurements give an overview of the conductivity of several measured samples.
Projective 3D-reconstruction of Uncalibrated Endoscopic Images
Authors: Faltin P. , Behrens A.
Published: March 2021

The most common medical diagnostic method for urinary bladder cancer is cystoscopy. This inspection of the bladder is performed by a rigid endoscope, which is usually guided close to the bladder wall. This causes a very limited field of view; difficulty of navigation is aggravated by the usage of angled endoscopes. These factors cause difficulties in orientation and visual control. To overcome this problem, the paper presents a method for extracting 3D information from uncalibrated endoscopic image sequences and for reconstructing the scene content. The method uses the SURF-algorithm to extract features from the images and relates the images by advanced matching. To stabilize the matching, the epipolar geometry is extracted for each image pair using a modified RANSAC-algorithm. Afterwards these matched point pairs are used to generate point triplets over three images and to describe the trifocal geometry. The 3D scene points are determined by applying triangulation to the matched image points. Thus, these points are used to generate a projective 3D reconstruction of the scene, and provide the first step for further metric reconstructions.
Nonlinear Aspects of Heat Pump Utilization
Authors: Najman R.
Published: March 2021

This work attempts to answer the question: How much can we believe that the coefficient of performance provided by the manufacturer is correct, when a heat pump is required to face the real load coming from changes of temperature? The paper summarizes some basics of heat pump theory and describes the results of numerical models.
Simulation of Hyperthermic Treatment Using the Matrix of Stripline Applicators
Authors: Vrbová B. , Víšek L.
Published: March 2021

This paper describes the design of a microwave stripline applicator for hyperthermic treatment, and the design of an anatomically based biological model, which is a necessary part of hyperthermia treatment planning for measuring the distribution of SAR. In this paper we compare the SAR distribution in a cylindrical homogeneous agar phantom (which has similar characteristics to biological tissue) and in an anatomically based biological model of the femur (which has been developed from a computer tomography scan) using a matrix of two applicators of the same type.
On Representations of sl(n, C) Compatible with a Z2-grading
Authors: Havlíček M. , Pelantová E. , Tolar J.
Published: March 2021

This paper extends existing Lie algebra representation theory related to Lie algebra gradings. The notion of a representation compatible with a given grading is applied to finite-dimensional representations of sl(n,C) in relation to its Z2-gradings. For representation theory of sl(n,C) the Gel’fand-Tseitlin method turned out very efficient. We show that it is not generally true that every irreducible representation can be compatibly graded.
Sharply Orthocomplete Effect Algebras
Authors: Kalina M. , Paseka J. , Riečanová Z.
Published: March 2021

Special types of effect algebras E called sharply dominating and S-dominating were introduced by S. Gudder in [7, 8]. We prove statements about connections between sharp orthocompleteness, sharp dominancy and completeness of E. Namely we prove that in every sharply orthocomplete S-dominating effect algebra E the set of sharp elements and the center of E are complete lattices bifull in E. If an Archimedean atomic lattice effect algebra E is sharply orthocomplete then it is complete.
Fractality of Fracture Surfaces
Authors: Ficker T.
Published: March 2021

A recently published fractal model of the fracture surfaces of porous materials is discussed, and a series of explanatory remarks are added. The model has revealed a functional dependence of the compressive strength of porous materials on the fractal dimension of fracture surfaces. This dependence has also been confirmed experimentally. The explanatory remarks provide a basis for better establishing the model.
A Study of the Interface of Soldered Joints of SnInAgTi Active Solder with Ito Ceramics
Authors: Provazník M. , Koleňák R.
Published: March 2021

This paper presents an analysis of the solderability ITO ceramics (In2O3/SnO2). The soft active solder SnInAgeTi was used for the experiments. The solder was activated by power ultrasound in air without flux. An analysis of the interface of the phases between the solder and the ceramic was carried out in order to discover the ultrasonic impacts on the active metal and to identify the mechanism of the joint on the ceramic side.
Cosmos, Time and Creation (Remarks to the Philosophical, Theological and Physical Conceptions of Creation)
Authors: Zamarovský P.
Published: March 2021

The concept of the beginning of Cosmos appears to be problematic. Not only ancient theological, but also present-day physical approaches evoke many questions. They originate in the definition of time, its dimensionality and its scale. If we accept the Standard Model, all physical processes including processes utilised in clocks (chronometric processes) lose their theoretical basis in the vicinity of the initial singularity. The singularity is hidden behind horizon. Does it mean that the singularity did not exist?
How to Protect Patients Digital Images/Thermograms Stored on a Local Workstation
Authors: Živčák J. , Roško M.
Published: March 2021

To ensure the security and privacy of patient electronic medical information stored on local workstations in doctors’ offices, clinic centers, etc., it is necessary to implement a secure and reliable method for logging on and accessing this information. Biometrically-based identification technologies use measurable personal properties (physiological or behavioral) such as a fingerprint in order to identify or verify a person’s identity, and provide the foundation for highly secure personal identification, verification and/or authentication solutions. The use of biometric devices (fingerprint readers) is an easy and secure way to log on to the system. We have provided practical tests on HP notebooks that have the fingerprint reader integrated. Successful/failed logons have been monitored and analyzed, and calculations have been made. This paper presents the false rejection rates, false acceptance rates and failure to acquire rates.
Ultra Low-Dispersion Spectroscopy with Gaia and Photographic Objective Prism Surveys
Authors: Hudec R. , Hudec L. , Klíma M.
Published: March 2021

This paper discusses the ultra low-dispersion spectroscopy to be applied in the ESA Gaia space observatory and the ground-based objective-prism plate surveys. Although the dispersion in plate surveys is usually larger than in the Gaia BP/RP spectrometers, the spectral resolutions differ by a factor of 2–3 only, since the resolution in ground-based spectra is seeing-limited. We argue that some of the algorithms developed for digitized objective-prism plates can also be applied for the Gaia spectra. At the same time, the plate results confirm the feasibility of observing strong emission lines with Gaia RP/BP.
4U 1909+07: a Hidden Pearl
Authors: Kreykenbohm I. , Fürst F. , Barrágan L. , Wilms J. , Rothschild R. E. , Suchy S. , Pottschmidt K.
Published: March 2021

We present a detailed spectral and timing analysis of the High Mass X-ray Binary (HMXB) 4U 1909+07 with INTEGRAL and RXTE. 4U1909+07 is a persistent accreting X-ray pulsar with a period of approximately 605 s. The period changes erratically consistent with a random walk expected for a wind accreting system. INTEGRAL detects the source with an average of 2.4 cps (corresponding to 15mCrab), but sometimes exhibits flaring activity up to 50 cps (i.e. 300mCrab). The strongly energy dependent pulse profile shows a double peaked structure at low energies and only a single narrow peak at energies above 20 keV. The phase averaged spectrum is well described by a powerlaw modified at higher energies by an exponential cutoff and photoelectric absorption at low energies. In addition at 6.4 keV a strong iron fluorescence line and at lower energies a blackbody component are present. We performed phase resolved spectroscopy to study the pulse phase dependence of the spectral parameters: while most spectral parameters are constant within uncertainties, the blackbody normalization and the cutoff folding energy vary strongly with phase.
Spectroscopy of the Stellar Wind in the Cygnus X-1 System
Authors: Miškovičová I. , Hanke M. , Wilms J. , Nowak M. A. , Pottschmidt K. , Schulz N. S.
Published: March 2021

The X-ray luminosity of black holes is produced through the accretion of material from their companion stars. Depending on the mass of the donor star, accretion of the material falling onto the black hole through the inner Lagrange point of the system or accretion by the strong stellar wind can occur. Cygnus X-1 is a high mass X-ray binary system, where the black hole is powered by accretion of the stellar wind of its supergiant companion star HDE226868. As the companion is close to filling its Roche lobe, the wind is not symmetric, but strongly focused towards the black hole. Chandra-HETGS observations allow for an investigation of this focused stellar wind, which is essential to understand the physics of the accretion flow. We compare observations at the distinct orbital phases of 0.0, 0.2, 0.5 and 0.75. These correspond to different lines of sight towards the source, allowing us to probe the structure and the dynamics of the wind.
Five-dimensional N = 4 Supersymmetric Mechanics
Authors: Bellucci S. , Krivonos S. , Sutulin A.
Published: March 2021

We perform an su(2) Hamiltonian reduction in the bosonic sector of the su(2)-invariant action for two free (4, 4, 0) supermultiplets. As a result, we get the five dimensional N = 4 supersymmetric mechanics describing the motion of an isospin carrying particle interacting with a Yang monopole. Some possible generalizations of the action to the cases of systems with a more general bosonic action constructed with the help of ordinary and twisted N = 4 hypermultiplets are considered.
Infinitesimal Algebraic Skeletons for a (2 + 1)-dimensional Toda Type System
Authors: Palese M. , Winterroth E.
Published: March 2021

A tower for a (2+1)-dimensional Toda type system is constructed in terms of a series expansion of operators which can be interpreted as generalized Bessel coefficients; the result is formulated as an analog of the Baker-Campbell-Hausdorff formula. We tackle the problem of the construction of infinitesimal algebraic skeletons for such a tower and discuss some open problems arising along our approach.
Propagators of Generalized Schrödinger Equations Related by First-order Supersymmetry
Authors: Schulze-Halberg A.
Published: March 2021

We construct an explicit relation between propagators of generalized Schrödinger equations that are linked by a first-order supersymmetric transformation. Our findings extend and complement recent results on the conventional case [1].
Toda Tau Functions with Quantum Torus Symmetries
Authors: Takasaki K.
Published: March 2021

The quantum torus algebra plays an important role in a special class of solutions of the Toda hierarchy. Typical examples are the solutions related to the melting crystal model of topological strings and 5D SUSY gauge theories. The quantum torus algebra is realized by a 2D complex free fermion system that underlies the Toda hierarchy, and exhibits mysterious “shift symmetries”. This article is based on collaboration with Toshio Nakatsu.
Surface Roughness and Porosity of Hydrated Cement Pastes
Authors: Ficker T. , Martišek D. , Jennings H. M.
Published: March 2021

. Seventy-eight graphs were plotted to describe and analyze the dependences of the height and roughness irregularities on the water-to-cement ratio and on the porosity of the cement hydrates. The results showed unambiguously that the water-to-cement ratio or equivalently the porosity of the specimens has a decisive influence on the irregularities of the fracture surfaces of this material. The experimental results indicated the possibility that the porosity or the value of the water-to-cement ratio might be inferred from the height irregularities of the fracture surfaces. It was hypothesized that there may be a similarly strong correlation between porosity and surface irregularity, on the one hand, and some other highly porous solids, on the other, and thus the same possibility to infer porosity from the surfaces of their fracture remnants.
Fracture Surfaces of Porous Materials
Authors: Ficker T.
Published: March 2021

A three-dimensional absolute profile parameter was used to characterize the height irregularities of the fracture surfaces of cement pastes. The dependence of these irregularities on porosity was studied and its non-linear character was proved. An analytical form for the detected non-linearity was suggested and then experimentally tested. The surface irregularities manifest scale-invariance properties.
3D Modelling of a Tunnel Re-excavation in Soft Ground
Authors: Hilar M.
Published: March 2021

The construction of the shallow tunnel at Brezno started using the Pre-Vault Method. The tunnel excavation, in complicated geological conditions, led to many difficulties which finally resulted in a collapse, when a significant part of the temporary tunnel lining collapsed. Various options for re-excavating the tunnel were evaluated prior to further construction. Finally a decision was made to separate the collapsed area into sections 9 m in length using 16 m-wide, transversally oriented pile walls, to improve the stability of the collapsed ground. The walls were constructed from the surface prior to excavation. It was also decided to re-excavate a collapsed area using the Sprayed Concrete Lining (SCL) method. Due to problematic soft ground conditions, which had been made even worse by the collapse, some additional support measures had to be considered prior to re-excavation (ground improvement, micropile umbrellas embedded into the pile walls, etc.)This paper describes numerical modelling of the tunnel re-excavation through the collapsed area. Initial calculations of the tunnel re-excavation were made using a 2D finite element method. Subsequently, further calculations to evaluate the rock mass behaviour in the collapsed area were provided in 3D. The 2D calculations were used to provide sensitivity studies, while 3D modelling was mainly used for evaluating the tunnel face stability (impact of the pile walls, impact of ground improvement) together with other factors (length of advances, moment of the temporary invert closure, etc.) The results of the modelling were compared with the monitoring results.The paper also briefly describes the construction experience (technical problems, performance of various support measures, etc.) The excavation and the primary lining construction were completed in 2006, and the tunnel was opened for traffic in April 2007.
Electronic Education
Authors: Vaněček D. , Jirsa J.
Published: March 2021

The age in which we are living nowadays is characterized by rapid innovation in the development of information and communication technologies (ICT). This innovation has a significant influence on the education process. This paper deals with e-learning.
Coquaternionic Quantum Dynamics for Two-level Systems
Authors: Brody D. C. , Graefe E. M.
Published: March 2021

The dynamical aspects of a spin-1/2 particle in Hermitian coquaternionic quantum theory are investigated. It is shown that the time evolution exhibits three different characteristics, depending on the values of the parameters of the Hamiltonian. When energy eigenvalues are real, the evolution is either isomorphic to that of a complex Hermitian theory on a spherical state space, or else it remains unitary along an open orbit on a hyperbolic state space. When energy eigenvalues form a complex conjugate pair, the orbit of the time evolution closes again even though the state space is hyperbolic.
Ito-Sadahiro numbers vs. Parry numbers
Authors: Masáková Z. , Pelantová E.
Published: March 2021

We consider a positional numeration system with a negative base, as introduced by Ito and Sadahiro. In particular, we focus on the algebraic properties of negative bases −β for which the corresponding dynamical system is sofic, which happens, according to Ito and Sadahiro, if and only if the (−β)-expansion of −β/(β + 1) is eventually periodic. We call such numbers β Ito-Sadahiro numbers, and we compare their properties with those of Parry numbers, which occur in the same context for the Rényi positive base numeration system.
The Horizons of Observability in PT-symmetric Four-site Quantum Lattices
Authors: Znojil M.
Published: March 2021

One of the key merits of PT-symmetric (i.e., parity times time reversal symmetric) quantum Hamiltonians H lies in the existence of a horizon of the stability of the system. Mathematically speaking, this horizon is formed by the boundary of the domain D(H) ⊂ RD of the (real) coupling strengths for which the spectrum of energies is real and non-degenerate, i.e., in principle, observable. It is shown here that even in the elementary circular four-site quantum lattices with D = 2 or D = 3 the domain of hidden Hermiticity D(H) proves multiply connected, i.e., topologically nontrivial.
Topology Control with Anisotropic and Sector Turning Antennas in Ad-hoc and Sensor Networks
Authors: Černý V.
Published: March 2021

During the last several years, technological advances have allowed the development of small, cheap, embedded, independent and rather powerful radio devices that can self-organise into data networks. Such networks are usually called ad-hoc networks or, sometimes, depending on the application field, sensor networks. One of the first standards for ad-hoc networks to impose itself as a fully industrial framework for data gathering and control over such devices is IEEE 802.15.4 and, on top of it, its pair network architecture: ZigBee. In the case of multiple radio devices clamped into a small geographical area, the lack of radio bandwidth becomes a major problem, leading to multiple data losses and unnecessary power drain from the batteries of these small devices. This problem is usually perceived as interference. The deployment of appropriate topology control mechanisms (TC) can solve interference. All of these algorithms calculate TC on the basis of isotropic antenna radiation patterns in the horizontal plane.
PhpHMM Tool for Generating Speech Recogniser Source Codes Using Web Technologies
Authors: Krejčí R.
Published: March 2021

This paper deals with the “phpHMM” software tool, which facilitates the development and optimisation of speech recognition algorithms. This tool is being developed in the Speech Processing Group at the Department of Circuit Theory, CTU in Prague, and it is used to generate the source code of a speech recogniser by means of the PHP scripting language and the MySQL database. The input of the system is a model of speech in a standard HTK format and a list of words to be recognised. The output consists of the source codes and data structures in C programming language, which are then compiled into an executable program. This tool is operated via a web interface.
Czech Participation in INTEGRAL: 1996–2011
Authors: Hudec R. , Blažek M. , Hudcová V.
Published: March 2021

The European Space Agency ESA INTEGRAL satellite launched in October 2002 is the first astrophysical satellite of the European Space Agency (ESA) with Czech participation. The results of the first 8 years of investigations of various scientific targets are briefly presented and discussed here, with emphasis on cataclysmic variables and blazars with the ESA INTEGRAL satellite with Czech participation.
Analysis and Simulation of the Pi of the Sky Detector Response
Authors: Piotrowski L. W. , Zarnecki A. F.
Published: March 2021

The Pi of the Sky project observes optical flashes of astronomical origin and other light sources variable on short timescales, down to tens of seconds. We search mainly for optical emissions of Gamma Ray Bursts, but also for variable stars, blazars, etc. Precise photometry with a very large field of view (20?×20?) requires a careful study and modelling of a point spread function (PSF), as presented in this paper.
The Optical Transient Search in the Bamberg Southern Sky Survey: Preliminary Results
Authors: Hudec R. , Kopel F. , Krapp P. , Heber U. , Cayé W.
Published: March 2021

A large fraction of gamma-ray bursts temporarily emit optical light, i.e. optical afterglows and optical transients. So far, optical transients have only been detected after related gamma-ray satellite detection. However, taking into account their optical magnitudes at maximum light, these objects should be detectable in various historical and recent optical surveys, including the photographic sky patrol. Here we report on an extended study based on blink-comparison of 5004 Bamberg Observatory Southern Sky Patrol Plates performed within a student high school project (Jugend Forscht).
Angular Distribution of GRBs
Authors: Balázs L. G. , Mészáros A. , Horváth I. , Bagoly Z. , Veres P. , Tusnády G.
Published: March 2021

We studied the complete randomness of the angular distribution of BATSE gamma-ray bursts (GRBs). Based on their durations and peak fluxes, we divided the BATSE sample into 5 subsamples (short1, short2, intermediate, long1, long2) and studied the angular distributions separately. We used three methods to search for non-randomness in the subsamples: Voronoi tesselation, minimal spanning tree, and multifractal spectra. To study any non-randomness in the subsamples we defined 13 test-variables (9 from Voronoi tesselation, 3 from the minimal spanning tree and one from the multifractal spectrum). We made Monte Carlo simulations taking into account the BATSE’s sky-exposure function. We tested therandomness by introducing squared Euclidean distances in the parameter space of the test-variables. We recognized that the short1, short2 groups deviate significantly (99.90%, 99.98%) from the fully random case in the distribution of the squared Euclidean distances but this is not true for the long samples. In the intermediate group, the squared Euclidean distances also give significant deviation (98.51%).
Production of Biocellulosic Ethanol from Wheat Straw
Authors: Ismail W. Ali , Braim R. Rasul , Ketuly K. Aziz , Awang Bujag D. Siti Shamsiah , Arifin Zainudin
Published: March 2021

Wheat straw is an abundant lignocellulosic feedstock in many parts of the world, and has been selected for producing ethanol in an economically feasible manner. It contains a mixture of sugars (hexoses and pentoses).Two-stage acid hydrolysis was carried out with concentrates of perchloric acid, using wheat straw. The hydrolysate was concentrated by vacuum evaporation to increase the concentration of fermentable sugars, and was detoxified by over-liming to decrease the concentration of fermentation inhibitors. After two-stage acid hydrolysis, the sugars and the inhibitors were measured. The ethanol yields obtained from by converting hexoses and pentoses in the hydrolysate with the co-culture of Saccharomyces cerevisiae and Pichia stipites were higher than the ethanol yields produced with a monoculture of S. cerevisiae. Various conditions for hysdrolysis and fermentation were investigated. The ethanol concentration was 11.42 g/l in 42 h of incubation, with a yield of 0.475 g/g, productivity of 0.272 gl ·h, and fermentation efficiency of 92.955 %, using a co-culture of Saccharomyces cerevisiae and Pichia stipites