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Search results for: EXISTENCE OF SOLUTIONS
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Giant Nernst effect in the incommensurate charge density wave state of P4W12O44
PublicationWe report the study of Nernst effect in quasi-low-dimensional tungsten bronze P4W12O44 showing a sequence of Peierls instabilities. We demonstrate that both condensation of the electronic carriers in the charge density wave state and the existence of high-mobility electrons and holes originating from the small pockets remaining in the incompletely nested Fermi surface give rise to a Nernst effect of a magnitude similar to that...
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A note on simple bifurcation of equilibrium forms of an elastic rod on a deformable foundation
PublicationWe study bifurcation of equilibrium states of an elastic rod on a two-parameter Winkler foundation. In the article "Bifurcation of equilibrium forms of an elastic rod on a two-parameter Winkler foundation" [Nonlinear Anal., Real World Appl. 39 (2018) 451-463] the existence of simple bifurcation points was proved by the use of the Crandall-Rabinowitz theorem. In this paper we want to present an alternative proof of this fact based...
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Curlicues generated by circle homeomorphisms
PublicationWe investigate the curves in the complex plane which are generated by sequences of real numbers being the lifts of the points on the orbit of an orientation preserving circle homeomorphism. Geometrical properties of these curves such as boundedness, superficiality, local discrete radius of curvature are linked with dynamical properties of the circle homeomorphism which generates them: rotation number and its continued fraction...
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On solvability of initial boundary-value problems of micropolar elastic shells with rigid inclusions
PublicationThe problem of dynamics of a linear micropolar shell with a finite set of rigid inclusions is considered. The equations of motion consist of the system of partial differential equations (PDEs) describing small deformations of an elastic shell and ordinary differential equations (ODEs) describing the motions of inclusions. Few types of the contact of the shell with inclusions are considered. The weak setup of the problem is formulated...
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The Palais–Smale condition for the Hamiltonian action on a mixed regularity space of loops in cotangent bundles and applications
PublicationWe show that the Hamiltonian action satisfies the Palais-Smale condition over a “mixed regular- ity” space of loops in cotangent bundles, namely the space of loops with regularity H^s, s ∈ (1/2, 1), in the baseand H^{1−s} in the fiber direction. As an application, we give a simplified proof of a theorem of Hofer-Viterbo on the existence of closed characteristic leaves for certain contact type hypersufaces in cotangent bundles.
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Analysis of a gene expression model
PublicationWe study a mathematical model of gene transcription and protein synthesis with negative feedback. We consider a system of equations taking into account the number of active binding sites, the way in which dimers bind to DNA and time delay in translation process. For a simplified model that consist of three ordinary differential equations with time delay we derive conditions for stability of the positive steady state and for the...
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A few steps more towards NPT bound entanglement
PublicationIn this paper, existence of bound entangled states with nonpositive partial transpose (NPT) is considered. As one knows, existence of such states would in particular imply nonadditivity of distillable entanglement. Moreover, it would rule out a simple mathematical description of the set of distillable states. The particular state, known to be 1-copy nondistillable and supposed to be bound entangled, is considered. The problem of...
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Interference aware Bluetooth scatternet (Re)configuration algorithm IBLUEREA
PublicationThe paper presents a new algorithm IBLUEREA, which enables reconfiguration of Bluetooth (BT) scatternet to reduce mutual interferences between BT and Wi-Fi (IEEE 802.11b) networks operating on the same area. IBLUEREA makes use of proposed procedure for modelling ISM environment around a given BT scatternet. The mechanism is based on estimation of the probabilities of successful (unsuccessful) frame transmissions. This determination...
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Detection of defects in PMMA beam using shear waves - numerical simulation and experiment
PublicationTest doświadczalny falami sprężystymi jest częścią systemu diagnostycznego belek. Autorzy badają pole przyspieszeń wywołane przepływem fal ultradźwiękowych i jego modyfikacje wynikające z wprowadzonych uszkodzeń belki. Artykuł porównuje wyniki eksperymentalne z symulacjami numerycznymi MES. The experimental test introduced in the paper is the part of the diagnostic system utilizing the elastic waves. The authors investigate the...
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Acceleration waves in the nonlinear micromorphic continuum
PublicationWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
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On well-posedness of the first boundary-value problem within linear isotropic Toupin–Mindlin strain gradient elasticity and constraints for elastic moduli
PublicationWithin the linear Toupin–Mindlin strain gradient elasticity we discuss the well-posedness of the first boundary-value problem, that is, a boundary-value problem with Dirichlet-type boundary conditions on the whole boundary. For an isotropic material we formulate the necessary and sufficient conditions which guarantee existence and uniqueness of a weak solution. These conditions include strong ellipticity written in terms of higher-order...
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A reliable synthesis of discrete-time H-inf control. Part I: basic theorems and J-lossless conjugators
PublicationThe paper gives a basis for solving many problems of numerically reliable synthesis of sub-optimal discrete-time control in H-inf. The approach is based on J-lossless factorisation of the delta-domain chain-scattering description of continuous-time plants being controlled. Relevant properties of poles and zeroes of chain-scattering models are given. Necessary and sufficient conditions for the existence of stabilising J-lossless...
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The cohomological span of LS-Conley index
PublicationIn this paper we introduce a new homotopy invariant – the cohomological span of LS-Conley index. We prove the theorems on the existence of critical points for a class of strongly indefinite functionals with the gradient of the form Lx+K(x), where L is bounded linear and K is completely continuous. We give examples of Hamiltonian systems for which our methods give better results than the Morse inequalities. We also give a formula...
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Completely entangled subspaces of entanglement depth k
PublicationWe introduce a class of entangled subspaces: completely entangled subspaces of entanglement depth k (k-CESs). These are subspaces of multipartite Hilbert spaces containing only pure states with an entanglement depth of at least k. We present an efficient construction of k-CESs of any achievable dimensionality in any multipartite scenario. Further, we discuss the relation between these subspaces and unextendible product bases (UPBs)....
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Fragment prywatnego księgozbioru gdańskiego kupca George'a Tönnigesa zachowany w zbiorach Biblioteki Gdańskiej PAN
PublicationIn the present holdings of the Gdańsk Library of the Polish Academy of Sciences beside the historical book collections once belonging to Gdańsk patricians (e.g. J. Uphagen, M. Hanow, W. Schlieff and A. Rosenberg), there are remains of a less known private book collection belonging in the 18th century to George Tönniges, a representative of the Gdańsk patriciate. On the one side, these several prints, fortunately survived up till...
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Quenching of bright and dark excitons via deep states in the presence of SRH recombination in 2D monolayer materials
PublicationTwo-dimensional (2D) monolayer materials are interesting systems due to an existence of optically non-active dark excitonic states. In this work, we formulate a theoretical model of an excitonic Auger process which can occur together with the trap-assisted recombination in such 2D structures. The interactions of intravalley excitons (bright and spin-dark ones) and intervalley excitons (momentum-dark ones) with deep states located...
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Quasilinear elliptic problem in anisotropic Orlicz–Sobolev space on unbounded domain
PublicationWe study a quasilinear elliptic problem $-\text{div} (\nabla \Phi(\nabla u))+V(x)N'(u)=f(u)$ with anisotropic convex function $\Phi$ on the whole $\R^n$. To prove existence of a nontrivial weak solution we use the mountain pass theorem for a functional defined on anisotropic Orlicz-Sobolev space $\WLPhispace(\R^n)$. As the domain is unbounded we need to use Lions type lemma formulated for Young functions. Our assumptions broaden...
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Dot-com and AI bubbles: Can data from the past be helpful to match the price bubble euphoria phase using dynamic time warping?
PublicationThe article investigates the existence of a price bubble in the artificial intelligence market, employing the Generalised Supremum Augmented Dickey-Fuller test and dynamic time warping methodology. It proposes a method to detect the end of the price bubble euphoria phase, generating an average profit of close to 7% over 5 days and over 10.5% over 20 days, with almost 90% effectiveness. The study found that the AI market experienced...
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Nilpotent singularities and chaos: Tritrophic food chains
PublicationLocal bifurcation theory is used to prove the existence of chaotic dynamics in two well-known models of tritrophic food chains. To the best of our knowledge, the simplest technique to guarantee the emergence of strange attractors in a given family of vector fields consists of finding a 3-dimensional nilpotent singularity of codimension 3 and verifying some generic algebraic conditions. We provide the essential background regarding...
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Hopf bifurcation in time‐delayed gene expression model with dimers
PublicationWe study a mathematical model of gene transcription and protein synthesis with negative feedback. We consider a system of equations taking into account the formation of dimers (i.e., complex formed by two protein monomers), the way in which dimers bind to DNA and time delay in translation process. For the model consisting of three ordinary differential equations with time delay, we derive conditions for stability of the positive...
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Marcinkiewicz Averages of Smooth Orthogonal Projections on Sphere
PublicationWe construct a single smooth orthogonal projection with desired localization whose average under a group action yields the decomposition of the identity operator. For any full rank lattice \Gamma ⊂ R^d , a smooth projection is localized in a neighborhood of an arbitrary precompact fundamental domain R^d / \Gamma. We also show the existence of a highly localized smooth orthogonal projection, whose Marcinkiewicz average under the...
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Weak Stability of Centred Quadratic Stochastic Operators
PublicationWe consider the weak convergence of iterates of so-called centred quadratic stochastic operators. These iterations allow us to study the discrete time evolution of probability distributions of vector-valued traits in populations of inbreeding or hermaphroditic species, whenever the offspring’s trait is equal to an additively perturbed arithmetic mean of the parents’ traits. It is shown that for the existence of a weak limit, it...
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Recurrent bowel-blood translocations of Escherichia coli with the unique virulence characteristics over three-year period in the patient with acute myeloid leukaemia – case report
PublicationIn patients with haematological malignancies, the bowel remains the main source of Escherichia coli bloodstream infections. We present the clinical example of recurrent bowel-blood translocations of E. coli with the unique virulence characteristics in a 55-year-old male with the diagnosis of acute myeloid leukaemia. The virulent factors profile of examined strains confirmed that the co-existence of genes papC, sfa, usp and cnf1,...
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Controlling the europium oxidation state in diopside through flux concentration
PublicationThis paper explores the connection between the H3BO3 flux concentration and the co-existence of Eu2+ and Eu3+ dopants within CaMgSi2O6 crystals (diopside). The samples were synthesised using a solid-state synthesis method under varying atmospheric conditions, including oxidative (air), neutral (N2), and reductive (H2/N2 mixture) environments. Additionally, some materials underwent chemical modification by partially substituting...
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Steady magnetohydrodynamic flow in a diverging channel with suction or blowing
PublicationAn analysis is made of steady two-dimensional divergent flow of an electrically conducting incompressible viscous fluid in a channel formed by two non-parallel walls, the flow being caused by a source of fluid volume at the intersection of the walls. The fluid is permeated by a magnetic field produced by an electric current along the line of intersection of the channel walls. The walls are porous and subjected to either suction...
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DIAGNOSIS OF MALIGNANT MELANOMA BY NEURAL NETWORK ENSEMBLE-BASED SYSTEM UTILISING HAND-CRAFTED SKIN LESION FEATURES
PublicationMalignant melanomas are the most deadly type of skin cancer but detected early have high chances for successful treatment. In the last twenty years, the interest of automated melanoma recognition detection and classification dynamically increased partially because of public datasets appearing with dermatoscopic images of skin lesions. Automated computer-aided skin cancer detection in dermatoscopic images is a very challenging task...
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Equivalence of equicontinuity concepts for Markov operators derived from a Schur-like property for spaces of measures
PublicationVarious equicontinuity properties for families of Markov operators have been – and still are – used in the study of existence and uniqueness of invariant probability for these operators, and of asymptotic stability. We prove a general result on equivalence of equicontinuity concepts. It allows comparing results in the literature and switching from one view on equicontinuity to another, which is technically convenient in proofs....
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Comments on various extensions of the Riemann–Liouville fractional derivatives : About the Leibniz and chain rule properties
PublicationStarting from the Riemann–Liouville derivative, many authors have built their own notion of fractional derivative in order to avoid some classical difficulties like a non zero derivative for a constant function or a rather complicated analogue of the Leibniz relation. Discussing in full generality the existence of such operator over continuous functions, we derive some obstruction Lemma which can be used to prove the triviality...
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Bi-based halide perovskites: Stability and opportunities in the photocatalytic approach for hydrogen evolution
PublicationIn this study, we successfully prepared Bi-based single perovskites of the A3Bi2I9 type (A = Cs, Rb, MA, FA), and, for the first time, attempted to experimentally obtain double perovskites Cs2B’BiI6 type (B′ = Ag, Au, In, Cu). Despite the premises available in theoretical studies, our research has proven the impossibility of the existence of double perovskites of this type. Nevertheless, both types of obtained materials were subjected...
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Cation sensing by diphenyl-azobenzocrowns
PublicationMetal cations complexation and proton binding by 13- and 16-membered diphenyl-azobenzocrowns and diphenyl-hydroxyazobenzocrowns were studied in acetonitrile using spectroscopic methods: UV–vis spectroscopy, spectrofluorimetry, and 1H NMR spectroscopy. Phenyl moieties in benzene rings were found to affect binding strength alkali and alkaline earth metal cations and hydrogen ion, and affect tautomeric equilibrium of hydroxyazobenzocrowns....
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Finite-window RLS algorithms
PublicationTwo recursive least-squares (RLS) adaptive filtering algorithms are most often used in practice, the exponential and sliding (rectangular) window RLS algorithms. This popularity is mainly due to existence of low-complexity versions of these algorithms. However, these two windows are not always the best choice for identification of fast time-varying systems, when the identification performance is most important. In this paper, we...
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Euro 2012 in Gdańsk, Poland. Is it worth using public funds?
PublicationThe aim of this study is to estimate the willingness - to - pay (WTP) among the community of the Pomeranian region, Poland in connection with intangible benefits and costs st emming from hosting the Euro 2012 in Gdansk. A survey conducted among 407 respondents was the source of information. The results of the study show that the average value of WTP benefit for the whole sample was 45,72 PLN2012 and WTP cost...
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The use of Markov chains in the social convergence analysis
PublicationThe main goal of this article is to analyze the social convergence process using Markov chains. In this research, term social convergence refers to the reduction of dispersion in the standard of living among countries. The use of Markov chains in the social convergence analysis allowed describing movements of observational units within the distribution and providing more details about the mechanism of the convergence process. A...
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Rotating rod and ball
PublicationWe consider a mechanical system consisting of an infinite rod (a straight line) and a ball (a massless point) on the plane. The rod rotates uniformly around one of its points. The ball is reflected elastically when colliding with the rod and moves freely between consecutive hits. A sliding motion along the rod is also allowed. We prove the existence and uniqueness of the motion with a given position and velocity at a certain time...
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The Method of a Two-Level Text-Meaning Similarity Approximation of the Customers’ Opinions
PublicationThe method of two-level text-meaning similarity approximation, consisting in the implementation of the classification of the stages of text opinions of customers and identifying their rank quality level was developed. Proposed and proved the significance of major hypotheses, put as the basis of the developed methodology, notably about the significance of suggestions about the existence of analogies between mathematical bases of...
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A NUMERICAL STUDY ON THE DYNAMICS OF DENGUE DISEASE MODEL WITH FRACTIONAL PIECEWISE DERIVATIVE
PublicationThe aim of this paper is to study the dynamics of Dengue disease model using a novel piecewise derivative approach in the sense of singular and non-singular kernels. The singular kernel operator is in the sense of Caputo, whereas the non-singular kernel operator is the Atangana–Baleanu Caputo operator. The existence and uniqueness of a solution with piecewise derivative are examined for the aforementioned problem. The suggested...
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Why the solvation water around proteins is more dense than bulk water
PublicationThe main aim of this work is to propose a rational explanation of commonly observed phenomenon of increasing water density within solvation shell of proteins. We have observed that geometry of the water-water hydrogen bond network within solvation layer differs from the one in bulk water and it is the effect of interactions of water molecules with protein surface. Altered geometry of the network reflects changes in the structure...
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Why the Solvation Water around Proteins Is More Dense than Bulk Water
PublicationThe main aim of this work is to propose a rational explanation of the commonly observed phenomenon of increasing water density within solvation shell of proteins. We have observed that the geometry of the water–water hydrogen bond network within solvation layer differs from the one in bulk water, and it is the result of interactions of water molecules with protein surface. Altered geometry of the network reflects changes in the...
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Shadow Economy in Poland Recent Evidence Based on Survey Data
PublicationThe book provides an estimate of the size of the shadow economy in Poland. Using analogous data, it traces core determinants of the existence of the shadow economy in Poland. It compares results with neighbouring countries, and if possible, the remaining Central-Eastern economies. The book tells why the problem of the unreported economic activity matters; it presents the problem from different angles―economic, social and institutional....
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Parseval Wavelet Frames on Riemannian Manifold
PublicationWe construct Parseval wavelet frames in L 2 (M) for a general Riemannian manifold M and we show the existence of wavelet unconditional frames in L p (M) for 1 < p < ∞. This is made possible thanks to smooth orthogonal projection decomposition of the identity operator on L 2 (M), which was recently proven by Bownik et al. (Potential Anal 54:41–94, 2021). We also show a characterization of Triebel–Lizorkin F sp,q (M) and Besov B...
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Index filtrations and Morse decomposition for discrete dynamical systems
PublicationOn a Morse decomposition of an isolated invariant set of a homeomorphism(discrete dynamical system) there are partial orderings defined by the homeomorphism.These are called admissible orderings of the...
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Roofing Materials as Pollution Emiters - Concentration Changes During Runoff
PublicationThe influence of roofing material on concentration of pollutants in roof runoff waters and changes of pollution concentration in time were investigated. In field studies four roofing material types were taken into consideration - ceramic tile, bituminous membrane, asbestos tile and zinc sheeting. Samples were collected since November 2007 to March 2008, anions, cations, metals, PAHs, pesticides and PCB were determined. The existence...
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FINITE GROUND CPW-FED UWB ANTENNA OVER THE METALLIC CYLINDRICAL SURFACES
PublicationThe investigation of finite ground coplanar fed ultra-wideband (UWB) antenna and the influence of its curvature and the proximity of circular metallic screen on the reflection coefficients and radiation characteristics is presented. The antenna is composed of two circular coplanar strips which enclose slot aperture of similar shape and is designed on a thin and flexible substrate which allows its bending. The antenna configuration...
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A subset of two adherence systems, acute pro-inflammatory pap genes and invasion coding dra, fim, or sfa, increases the risk of Escherichia coli translocation to the bloodstream
PublicationAn analysis of the phylogenetic distribution and virulence genes of Escherichia coli isolates which predispose this bacteria to translocate from the urinary tract to the bloodstream is presented. One-dimensional analysis indicated that the occurrence of P fimbriae and α-hemolysin coding genes is more frequent among the E. coli which cause bacteremia. However, a two-dimensional analysis revealed that a combination of genes coding...
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Estimation of Housing Demand with Adaptive Neuro-Fuzzy Inference Systems (ANFIS)
PublicationIt has always been important to anticipate the demand for a product. To determine the demand for any product, the parameters such as the economic situation and the demands of the rival products are used generally. Especially in the housing sector, which is the locomotive sector for emerging countries, it is critical to anticipate housing demand and its relationship with economic variables. Because of that, economists, real estate...
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Negative result about the construction of genuinely entangled subspaces from unextendible product bases
PublicationUnextendible product bases (UPBs) provide a versatile tool with various applications across different areas of quantum information theory. Their comprehensive characterization is thus of great importance and has been a subject of vital interest for over two decades now. An open question asks about the existence of UPBs, which are genuinely unextendible, i.e., they are not extendible even with biproduct vectors. In other words,...
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Charge-based deep level transient spectroscopy of B-doped and undoped polycrystalline diamond films
PublicationThe undoped and B-doped polycrystalline diamond thin film was synthesized by hot filament chemical vapor deposition and microwave plasma, respectively. The structural characterization was performed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The electrical properties of synthesized diamond layer were characterized by dc-conductivity method and charge deep level transient spectroscopy. The B-doped...
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The potential of Web-GIS and geovisual analytics in the context of marine cadastre
PublicationThe importance of the marine environment to human existence makes it imperative that information models represent the multidimensional nature of reality as closely as possible in order to facilitate good governance. Information regarding jurisdiction, as well as the effects of formal law and community interests on the marine environment (e.g. nature and spatial extents as well as rights, responsibilities, restrictions etc.) would...
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Poszukiwanie dobrych odpowiedzi na źle postawione pytania, rzecz o przedsiębiorczości kobiet
PublicationWomen entrepreneurship has been the subject of research for many years and its results are often compared against the men entrepreneurship results. The conducted research has often been aimed at identification/recognition of the differences between the entrepreneurs of opposite gender. The lack of satisfactory proof for the existence of the differences has been attributed by some determined researchers to inappropriate research...
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Gender, equality, science and information systems
PublicationIn the entire Europe more women than men graduate from tertiary education institutes1. However, they are underrepresented in scientific and engineering disciplines. Women researchers still constitute a minority in the Government and Higher Education Sectors that both are related to power. A number of industry reports highlight a low number of women in IT occupations2. The EU Member States have, on political levels, committed themselves...