bluuebunny/crossref_metadata_2025_split huggingface dataset:
Horseshoe Kidney with Hydronephrosis – Tales of the Unexpected
Authors: Nikolova Milena , Krasteva R. , Bogov B. , Tsocheva T. , Milenova Vi. , Petkov K. , Chernev N. 
Published: March 2018

Abstract
Horseshoe kidney is an inborn renal fusion anomaly. It is frequently associated with renal stones and infections. The diagnosis is made using imaging methods - ultrasound, X-ray of the abdomen and intravenous pyelography, computed tomography (CT), magnetic resonance imaging (MRI) and radionuclide investigations. The diagnosis sometimes is hard, especially when other abnormalities are present, i.e. hydronephrosis, nephrolithiasis, stenosis of the ureteropelvic junction, etc. The authors present a male patient with horseshoe kidney and unilateral hydronephrosis due to obstruction of the ureteropelvic junction and discuss the diagnosis of horseshoe kidney and the diagnostic approach in such patients.
Trace Elements and Vitamin D in Gestational Diabetes
Authors: Genova Mariana , Atanasova B. , Ivanova I. , Todorova K. , Svinarov D. 
Published: March 2018

Abstract
Gestational diabetes mellitus (GDM), one of the most common pregnancy complications, is defined as glucose intolerance with onset or first recognition during pregnancy. Its prevalence varies worldwide in dependence on characteristics of the underlying population and applied diagnostic criteria. The etiology is multifactorial and not sufficiently elucidated. Available evidence suggests that the base of pathogenesis is relatively diminished insulin secretion coupled with pregnancy-induced insulin resistance. Modifiable and non-modifiable risk factors for development have been identified. Trace elements and vitamin D could be contributed to modifiable factors for prediction the risk in a large population. Essential trace elements in pregnancy are necessary to overcome systemic oxidative, metabolic and inflammatory stress. Evidence, still inconclusive, has been accumulated about the relation between higher incidence of vitamin D failure/deficiency during pregnancy and GDM. The lower level of 25-OH vitamin D could be associated with increased risk for anemia development, also including pregnant women. This review intends to provide an overview of the possible link between both vitamin D and trace elements as risk factors for GDM development.
Methods for Ultrasound Screening of Cardiovascular Diseases in Type 2 Diabetic Patients
Authors: Kundurdzhiev A. , Markova Alexandra 
Published: March 2018

Abstract
Diabetes mellitus is a chronic disorder that affects predominantly the carbohydrate metabolism, but also the biotransformation of proteins and fat. Many intra- and extracellular metabolic mechanisms are impaired which leads to structural changes in the vascular wall and the heart muscle. This eventually causes their functional deterioration and the end result is clinical manifestation of macrovascular incidents or heart failure. People with perturbations of the glucose metabolism (impaired fasting glucose, impaired glucose tolerance and insulin resistance) are also with a higher risk of cardiovascular diseases, even before the diagnosis of diabetes. Nowadays we have a cheap, easy and non-invasive method for early diagnosis of cardiovascular disorders, way before their clinical manifestation, and that is the ultrasound methodology. The echocardiography is a valuable technique for the detection of changes in the myocardial structure and its contractility. The tissue Doppler ultrasound is a more precise method that can detect the slightest aberrations in the heart muscle function, that could not be seen with the conventional echocardiography. Subclinical atherosclerotic changes can be determined with a Doppler scan of the big arteries (carotids, renal arteries), and the subsequent calculation of their resistive index and of the intima-media thickness. There are a lot of studies in this field which show that the structural and functional impairment could be diagnosed in diabetic patients without any complaints and with otherwise healthy hearts. This means that these diagnostic methods should be used in the routine clinical examination of every diabetic individual in order to predict and possibly prevent major cardiovascular events and severe heart failure.
Non-Invasive and Minimum Invasive Concepts in Prevention, Cariology and Endodontics – from Research and Science to Practice
Authors: Boteva Ekaterina 
Published: March 2018

Abstract
The minimum invasive dental concept is based on practical experience of more than 30 years negative trends from the use of resin materials in distal teeth and early metal-ceramic “aesthetic” crowns and bridges. The scientific dental research includes all aspects of the conservative dentistry treatment which are scientifically and clinically proved with most up to date methods and tests: anthropometric, epidemiological, biochemical, immunohistochemical, electron microscopy, polarized light microscopy, light induced fluorescence, microradiography, microbiology, genetic tests, etc. Experiments in vitro, animal tests, clinical research in the last 34 years are focused in the field of prevention of dental caries, treatment of precavitated precarious lesions with nanotechnologies, preparation of hard dental tissues with most conservative techniques, adhesive restoration methods with amalgam and resins, backup in endodontics in root canals preparation methods and in pins and posts fixations. The conclusions can be focused on basic principles and refocused in the 21st century like: Dental caries is not only predictable and controlled disease but is also a polyetiological disease on a community and population levels and uni- or bi-etiological on an individual level. The minimum invasive dental concept in cariology and endodontics leads to prevention of early extractions, early prosthetic medical procedures and to lifetime dental health. This plays a key role in prevention of metabolic disorders and gastrointestinal diseases.
A geometric approach to structural model matching by output feedback in linear impulsive systems
Authors: Zattoni Elena 
Published: March 2018

Abstract
This paper provides a complete characterization of solvability of the problem of structural model matching by output feedback in linear impulsive systems with nonuniformly spaced state jumps. Namely, given a linear impulsive plant and a linear impulsive model, both subject to sequences of state jumps which are assumed to be simultaneous and measurable, the problem consists in finding a linear impulsive compensator that achieves exact matching between the respective forced responses of the linear impulsive plant and of the linear impulsive model, by means of a dynamic feedback of the plant output, for all the admissible input functions and for all the admissible sequences of jump times. The solution of the stated problem is achieved by reducing it to an equivalent problem of structural disturbance decoupling by dynamic feedforward. Indeed, this latter problem is formulated for the so-called extended linear impulsive system, which consists of a suitable connection between the given plant and a modified model. A necessary and sufficient condition for the solution of the structural disturbance decoupling problem is first shown. The proof of sufficiency is constructive, since it is based on the synthesis of the compensator that solves the problem. The proof of necessity is based on the definition and the geometric properties of the unobservable subspace of a linear impulsive system subject to unequally spaced state jumps. Finally, the equivalence between the two structural problems is formally established and proven.
Distributed scheduling of measurements in a sensor network for parameter estimation of spatio-temporal systems
Authors: Patan Maciej , Kowalów Damian 
Published: March 2018

AbstractThe main aim of the paper is to develop a distributed algorithm for optimal node activation in a sensor network whose measurements are used for parameter estimation of the underlying distributed parameter system. Given a fixed partition of the observation horizon into a finite number of consecutive intervals, the problem under consideration is to optimize the percentage of the total number of observations spent at given sensor nodes in such a way as to maximize the accuracy of system parameter estimates. To achieve this, the determinant of the Fisher information matrix related to the covariance matrix of the parameter estimates is used as the qualitative design criterion (the so-called D-optimality). The proposed approach converts the measurement scheduling problem to a convex optimization one, in which the sensor locations are given a priori and the aim is to determine the associated weights, which quantify the contributions of individual gaged sites to the total measurement plan. Then, adopting a pairwise communication scheme, a fully distributed procedure for calculating the percentage of observations spent at given sensor locations is developed, which is a major novelty here. Another significant contribution of this work consists in derivation of necessary and sufficient conditions for the optimality of solutions. As a result, a simple and effective computational scheme is obtained which can be implemented without resorting to sophisticated numerical software. The delineated approach is illustrated by simulation examples of a sensor network design for a two-dimensional convective diffusion process.
An adaptive observer design approach for a class of discrete-time nonlinear systems
Authors: Srinivasarengan Krishnan , Ragot José , Aubrun Christophe , Maquin Didier 
Published: March 2018

Abstract
We consider the problem of joint estimation of states and some constant parameters for a class of nonlinear discrete-time systems. This class contains systems that could be transformed into a quasi-LPV (linear parameter varying) polytopic model in the Takagi-Sugeno (T-S) form. Such systems could have unmeasured premise variables, a case usually overlooked in the observer design literature. We assert that, for such systems in discrete-time, the current literature lacks design strategies for joint state and parameter estimation. To this end, we adapt the existing literature on continuous-time linear systems for joint state and time-varying parameter estimation. We first develop the discrete-time version of this result for linear systems. A Lyapunov approach is used to illustrate stability, and bounds for the estimation error are obtained via the bounded real lemma. We use this result to achieve our objective for a design procedure for a class of nonlinear systems with constant parameters. This results in less conservative conditions and a simplified design procedure. A basic waste water treatment plant simulation example is discussed to illustrate the design procedure.
Robust stabilization using a sampled-data strategy of uncertain neutral state-delayed systems subject to input limitations
Authors: Fezazi Nabil El , Haoussi Fatima El , Tissir El Houssaine , Alvarez Teresa , Tadeo Fernando 
Published: March 2018

Abstract
Stabilization of neutral systems with state delay is considered in the presence of uncertainty and input limitations in magnitude. The proposed solution is based on simultaneously characterizing a set of stabilizing controllers and the associated admissible initial conditions through the use of a free weighting matrix approach. From this mathematical characterization, state feedback gains that ensure a large set of admissible initial conditions are calculated by solving an optimization problem with LMI constraints. Some examples are presented to compare the results with previous approaches in the literature.
Bounds on the rate of convergence for one class of inhomogeneous Markovian queueing models with possible batch arrivals and services
Authors: Zeifman Alexander , Razumchik Rostislav , Satin Yacov , Kiseleva Ksenia , Korotysheva Anna , Korolev Victor 
Published: March 2018

Abstract
In this paper we present a method for the computation of convergence bounds for four classes of multiserver queueing systems, described by inhomogeneous Markov chains. Specifically, we consider an inhomogeneous M/M/S queueing system with possible state-dependent arrival and service intensities, and additionally possible batch arrivals and batch service. A unified approach based on a logarithmic norm of linear operators for obtaining sharp upper and lower bounds on the rate of convergence and corresponding sharp perturbation bounds is described. As a side effect, we show, by virtue of numerical examples, that the approach based on a logarithmic norm can also be used to approximate limiting characteristics (the idle probability and the mean number of customers in the system) of the systems considered with a given approximation error.
Iterative methods for efficient sampling-based optimal motion planning of nonlinear systems
Authors: Ha Jung-Su , Choi Han-Lim , Jeon Jeong Hwan 
Published: March 2018

Abstract
This paper extends the RRT* algorithm, a recently developed but widely used sampling based optimal motion planner, in order to effectively handle nonlinear kinodynamic constraints. Nonlinearity in kinodynamic differential constraints often leads to difficulties in choosing an appropriate distance metric and in computing optimized trajectory segments in tree construction. To tackle these two difficulties, this work adopts the affine quadratic regulator-based pseudo-metric as the distance measure and utilizes iterative two-point boundary value problem solvers to compute the optimized segments. The proposed extension then preserves the inherent asymptotic optimality of the RRT* framework, while efficiently handling a variety of kinodynamic constraints. Three numerical case studies validate the applicability of the proposed method.
Stabilization of an epidemic model via an N-periodic approach
Authors: Cantó Begoña , Coll Carmen , Sánchez Elena 
Published: March 2018

Abstract
We analyze the evolution of an infectious disease by combining different groups of a population when the route of transmission is via encounters with free-living virulent organisms that can survive for a long time outside the individual. This study involves matrix analysis of lower triangular block matrices and some of their spectral properties. We propose an N-periodic control strategy in order to stabilize the disease around the disease-free equilibrium point.
Some classes of statistical distributions. Properties and Applications
Authors: Băncescu Irina 
Published: March 2018

Abstract
We propose a new method of constructing statistical models which can be interpreted as the lifetime distributions of series-parallel/parallel- series systems used in characterizing coherent systems. An open problem regarding coherent systems is comparing the expected system lifetimes. Using these models, we discuss and establish conditions for ordering of expected system lifetimes of complex series-parallel/parallel-series systems. Also, we consider parameter estimation and the analysis of two real data sets. We give formulae for the reliability, hazard rate and mean hazard rate functions.
Tripotents: a class of strongly clean elements in rings
Authors: Călugăreanu Grigore 
Published: March 2018

Abstract
Periodic elements in a ring generate special classes of strongly clean elements. In particular, elements b such that b = b3+, which are called tripotents and include idempotents, negative of idempotents and order 2 units, are strongly clean. Such elements are determined in 2×2 matrix rings over commutative domains or over arbitrary division rings and for rings of integers modulo n.
Anti-plane crack in human bone. I. Mathematical modelling
Authors: Crăciun Eduard Marius , Marin Marin , Răbâea Adrian 
Published: March 2018

Abstract
We consider an anti-plane crack in a bone, considered as an initially deformed orthotropic, linear elastic composite material. Elastic incremental fields in the composite material are obtained following theories of Guz’s representation and of Riemann-Hilbert problem. Critical values of crack propagation angle are determined using Sih’s generalized criterion.
Generalized Horadam Polynomials and Numbers
Authors: Djordjevic Snezana S. , Djordjevic Gospava B. 
Published: March 2018

Abstract
We consider the polynomials hn,m(x) (m ≥ 2) and the numbers hn,m (x = 1), which are the generalized Horadam polynomials and the generalized Horadam numbers, respectively. We also consider the polynomials h(s)
n,m(x)- convolutions of the polynomials hn,m(x), and the sequence of numbers h(s)
n,m- convolutions of the numbers hn,m, where s ≥ 0.
Transverse vibrations analysis of a beam with degrading hysteretic behavior by using Euler-Bernoulli beam model
Authors: Groza Ghiocel , Mitu Ana-Maria , Pop Nicolae , Sireteanu Tudor 
Published: March 2018

Abstract
The paper is based on the analytical and experimental results from [14], [15] and reveals, by mathematical methods, the degradation of ma- terial stifiness due to the decrease of the first natural frequency, when the driving frequency is slightly lower than the first natural frequency of the undegradated structure. By considering the vibration of the uni- form slender cantilever beam as an oscillating system with degrading hysteretic behavior the following equation is considered subjected to the boundary conditions To approximate the solution of the this problem, we use the method of Newton interpolating series (see [6]) and the Taylor series method (see [8]).
Laplace operators on holomorphic Lie algebroids
Authors: Ionescu Alexandru 
Published: March 2018

Abstract
The paper introduces Laplace-type operators for functions defined on the tangent space of a Finsler Lie algebroid, using a volume form on the prolongation of the algebroid. It also presents the construction of a horizontal Laplace operator for forms defined on the prolongation of the algebroid. All the Laplace operators considered in the paper are also locally expressed using the Chern-Finsler connection of the algebroid.
Commutator Subgroups of Generalized Hecke and Extended Generalized Hecke Groups
Authors: Kaymak Şule , Demır Bilal , Koruoğlu Özden , Şahin Recep 
Published: March 2018

Abstract
Let p and q be integers such that 2 ≤ p ≤ q; p + q > 4 and let Hp,q be the generalized Hecke group associated to p and q: The generalized Hecke group Hp,q is generated by X(z) = -(z-λp)-1 and Y (z) = -(z+ λq)-1 where λp = 2 cos ≤ π/p and λq = 2 cos π/q . The extended generalized Hecke group H̅p,q is obtained by adding the reection R(z) = 1/z̅ to the generators of generalized Hecke group Hp,q: In this paper, we study the commutator subgroups of generalized Hecke groups Hp,q and extended generalized Hecke groups H̅p,q.
Exact Formula for Computing the Hyper-Wiener Index on Rows of Unit Cells of the Face-Centred Cubic Lattice
Authors: Mujahed Hamzeh , Nagy Benedek 
Published: March 2018

Abstract
Similarly to Wiener index, hyper-Wiener index of a connected graph is a widely applied topological index measuring the compactness of the structure described by the given graph. Hyper-Wiener index is the sum of the distances plus the squares of distances between all unordered pairs of vertices of a graph. These indices are used for predicting physicochemical properties of organic compounds. In this paper, the graphs of lines of unit cells of the face-centred cubic lattice are investigated. The graphs of face-centred cubic lattice contain cube points and face centres. Using mathematical induction, closed formulae are obtained to calculate the sum of distances between pairs of cube points, between face centres and between cube points and face centres. The sum of these formulae gives the hyper-Wiener index of graphs representing face-centred cubic grid with unit cells connected in a row. In connection to integer sequences, a recurrence relation is presented based on binomial coefficients.
Power sums in hyperbolic Pascal triangles
Authors: Németh László , Szalay László 
Published: March 2018

Abstract
In this paper, we describe a method to determine the power sum of the elements of the rows in the hyperbolic Pascal triangles corresponding to –4, q} with q ≥ 5. The method is based on the theory of linear recurrences, and the results are demonstrated by evaluating the kth power sum in the range 2 ≤ k ≤ 11.
Weighted Entropic Copula from Preliminary Knowledge of Dependence
Authors: Panait Ioana 
Published: March 2018

Abstract
This paper introduces a weighted entropic copula from preliminary knowledge of dependence. Considering a copula with common distribution we formulate the weighted entropy dependence model (WMEC). We give an approximator for the copula function of this problem. Also, we discuss some asymptotical properties regarding the unknown parameters of the model.
Consequences of a Spectacle? Alleged Match-Fixing in the National Basketball Association Western Conference Finals of 2002
Authors: Muniowski Łukasz 
Published: March 2018

Abstract
No major professional sports league epitomizes Guy Debord’s idea of the spectacle more than the NBA. The league was the first to understand the importance of highlights and global expansion, and participated in creating the first branded superstar in Michael Jordan. Naturally there are some controversies surrounding the rise to its present-day status, like the (supposedly) fixed 1985 draft or Michael Jordan’s (supposedly) enforced first retirement. One of the most controversial events in recent league history took place during Game Six of the 2002 Western Conference Finals between the Los Angeles Lakers and the Sacramento Kings. A lot of controversial calls by the referees allowed the Lakers to win the game and eventually the series. As the Lakers were about to get eliminated, the league officials allegedly encouraged referees to force a Game Seven. The problem with the allegations was that they were made public by former referee Tim Donaghy, who himself used to bet on games. David Stern, the league’s former commissioner was referring to Donaghy’s gambling addiction as the reason for the falsity of his statements. My paper uses the game in question as a case study in order to present the spectacular aspects of the NBA.
Justice at Sport Clubs According to the Theory of Utilitarianism and Libertarianism
Authors: Zimányi Róbert G. , Geczi Gábor 
Published: March 2018

Abstract
Today’s sport clubs are exposed to turbulently changing circumstances to which they must adapt. If we want to talk about quality sport clubs, we have to find the qualitative criterion that justifies them. This must then be accepted by society as well. Such aspects of quality and evaluation may show justice. Only one truth exists. Thus the question is how and by what principles we should interpret it. Justice can play a key role in the operation of sport clubs as a moral element. This justice must not necessarily be linked to equality. The goal of this study is to interpret justice as a quality factor in sport clubs. The other goal of the study is to present some theories of justice related to sport. The study examines Bentham’s utilitarianism, Mill’s higher pleasures, and the ideas of libertarianism concerning justice. The theories of justice in addition to social processes also play a key role in today’s sport clubs. During the interpretations, it is important to distinguish between competitive and non-competitive sport clubs in relation to justice. It also depends on the practical applicability of the theory of justice. The practical application of theories of justices should be thoroughly investigated in the life of sport clubs. Then the sport clubs’ management must decide which theory of justice should be introduced. The key question concerns how to apply it consistently in practice while taking into account the interests of existing and prospective members. Finding the potential qualitative key factors for the sport clubs’ qualification is a complex activity. Besides happiness and justice, many other ancient and presently valued virtues can be relevant qualities and distinctive aspects among sport clubs.