3,922 research outputs found

    Generalized β\beta-conformal change and special Finsler spaces

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    In this paper, we investigate the change of Finslr metrics L(x,y)Lˉ(x,y)=f(eσ(x)L(x,y),β(x,y)),L(x,y) \to\bar{L}(x,y) = f(e^{\sigma(x)}L(x,y),\beta(x,y)), which we refer to as a generalized β\beta-conformal change. Under this change, we study some special Finsler spaces, namely, quasi C-reducible, semi C-reducible, C-reducible, C2C_2-like, S3S_3-like and S4S_4-like Finsler spaces. We also obtain the transformation of the T-tensor under this change and study some interesting special cases. We then impose a certain condition on the generalized β\beta-conformal change, which we call the b-condition, and investigate the geometric consequences of such condition. Finally, we give the conditions under which a generalized β\beta-conformal change is projective and generalize some known results in the literature.Comment: References added, some modifications are performed, LateX file, 24 page

    The Casimir force in noncommutative Randall-Sundrum models

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    In this paper we study the effect of spacetime noncommutativity in the 5-dimensional Randall-Sundrum brane worlds on the Casimir force acting on a pair of parallel plates. We show that the presence of a noncommutative scale length affects the nature of the Casimir force for small plate separation. Using accurate experimental bounds for the Casimir force in parallel plate geometry, we find an upper bound for the noncommutative cutoff of the order of 10310^{3} TeV, and that the size of the interbrane distance in RSI model is approximately given by kR20.5kR\lesssim20.5 and kR18.4kR\lesssim18.4 for k=1019k=10^{19} GeV and k=1016k=10^{16}GeV, respectively.Comment: 20 pages, 5 figures, accepted for publication in Phys. Rev.

    THE EFFECTS OF TEMPERATURE DEPENDENT VISCOSITY AND VISCOUS DISSIPATION ON MHD CONVECTION FLOW FROM AN ISOTHERMAL HORIZONTAL CIRCULAR CYLINDER IN THE PRESENCE OF STRESS WORK AND HEAT GENERATION

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    Temperature dependent viscosity and Viscous Dissipation effects are considered on hydromagnetic natural convection flow from horizontal circular cylinder immersed in an electrically conducting fluid with viscosity proportional to a linear function of temperature in the presence of stress work and heat generation. The partial differential governing equations are transformed to dimensionless forms. The numerical computations are carried out for several values of physical parameters involved in the transformed equations. The resulting nonlinear system of partial differential equations is solved numerically by Keller box method which is an implicit finite difference technique with Newton's linearization method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. To support the accuracy of the numerical results, a comparison is made with known results from the open literature for some particular cases of the present study and the results are found to be in good agreement

    Some entanglement features of three-atoms Tavis-Cummings model: Cooperative case

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    In this paper we consider a system of identical three two-level atoms interacting at resonance with a single-mode of the quantized field in a lossless cavity. The initial cavity field is prepared in the coherent state while the atoms are taken initially to be either in the uppermost excited state "eee>|eee>" or The GHZ\textmd{GHZ}-state or the W\textmd{W}-state. For this system we investigate different kinds of atomic inversion and entanglement, which arise between the different parts of the system due to the interaction. Also the relationship, between entanglement and some other nonclassical effects in the statistical properties, such as collapses and revivals in the atomic inversion where superharmonic effects appear, is discussed. The QQ-functions for different cases are discussed. Most remarkably it is found that the GHZ\textmd{GHZ}-state is more robust against energy losses, showing almost coherent trapping and Schr\"odinger-cat states can not be produced from such state. Also the entanglement of GHZ\textmd{GHZ}-state is more robust than the W\textmd{W}-state. Another interesting feature found is that the state which has no pairwise entanglement initially will have a much improvement of such pairwise entanglement through the evolution. Sudden death and sudden revival of atoms-pairwise entanglement are produced with the W\textmd{W}-state.Comment: 14 pages, 7 figure

    Impact of Applying Fraud Detection and Prevention Instruments in Reducing Occupational Fraud: Case study: Ministry of Health (MOH) in Gaza Strip

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    The study aimed to identify the effect of applying detection and prevention tools for career fraud in combating and preventing fraud and reducing its risks through an applied study on Palestinian Ministry of Health in Gaza Strip, Palestine. To achieve the objectives of the study, the researchers used the questionnaire as a main tool to collect data, and the descriptive and analytical approach to conducting the study. The study population consisted of (501) supervisory employees working at MOH in Gaza Strip, Palestine. The researchers used the stratified random sample method and the multiple regression method to measure the effect. The study concluded a set of results, the most important of which is a positive evaluation among respondents about the levels of application of tools to detect and prevent job fraud within MOH, and the presence of a high interest in tools to prevent job fraud during the implementation of its various work. The study recommended the necessity for the Palestinian National Authority to develop and approve laws regulating health sector, so that those laws guarantee the prevention of conflicts of interest, especially for the category of doctors, by preventing job duplication of doctors working in the government sector. Also study recommended the need for MOH to adopt principles of health sector governance and begin immediately to implement them. This process to ensure transparency, disclosure and accountability in the business framework in a manner that realizes the effective protection of stakeholders and does not compromise or discriminate in the application of these principles, which ensures that all forms of job fraud are organized in an organized manner and within fixed legal frameworks

    On dimension reduction in Gaussian filters

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    A priori dimension reduction is a widely adopted technique for reducing the computational complexity of stationary inverse problems. In this setting, the solution of an inverse problem is parameterized by a low-dimensional basis that is often obtained from the truncated Karhunen-Loeve expansion of the prior distribution. For high-dimensional inverse problems equipped with smoothing priors, this technique can lead to drastic reductions in parameter dimension and significant computational savings. In this paper, we extend the concept of a priori dimension reduction to non-stationary inverse problems, in which the goal is to sequentially infer the state of a dynamical system. Our approach proceeds in an offline-online fashion. We first identify a low-dimensional subspace in the state space before solving the inverse problem (the offline phase), using either the method of "snapshots" or regularized covariance estimation. Then this subspace is used to reduce the computational complexity of various filtering algorithms - including the Kalman filter, extended Kalman filter, and ensemble Kalman filter - within a novel subspace-constrained Bayesian prediction-and-update procedure (the online phase). We demonstrate the performance of our new dimension reduction approach on various numerical examples. In some test cases, our approach reduces the dimensionality of the original problem by orders of magnitude and yields up to two orders of magnitude in computational savings

    THE ROLE OF ARTIFICIAL INTELLIGENCE AND MACHINE LEARNING IN PRESERVING CULTURAL HERITAGE AND ART WORKS VIA VIRTUAL RESTORATION

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    Artifacts including paintings, drawings, prints, mosaics, sculptures, historical structures and monuments, as well as archaeological sites present a key part of our cultural heritage. It consists of Intangible culture (such as folklore, traditions, language, and knowledge), tangible culture (such as buildings, monuments, landscapes, archival materials, books, works of art, and artifacts), and natural heritage (such as biodiversity and culturally significant landscapes) .Now we will concentrate on tangible culture and its problems and how to handle them. One of its biggest problems is that over the years the nature of the materials used in the creation of the artwork make them prone to cracks, fractures, stains, and colors fading and blurring. The causes of their damage could be of natural or human- related reasons. The natural causes range from war, fires, earthquakes, natural disasters and the human-related causes range from accidental events like to pollution which results of climate changes, which like acid rain. It is a must to consider the environment in which you store your artwork. Our regular environment's light, heat, moisture, and pollution levels can lead to harmful chemical and physical reactions in artwork. There are several reasons why it is necessary to preserve ancient works of art. The fact that it enables us to comprehend the historical and cultural context of the era in which it was made is one of the key factors. Then preserving our artworks is a must and this can be done by manual techniques or using machine learning algorithms

    "MELUHA" sózott hal kémiai és mikrobiológiai vizsgálata

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    Die chemische Zusammensetzung und der mikrobiologische Zustand des gesalzten Fisches „Meluha“, ferner die Zusammensetzung der essentiellen und freien Aminosäuren der Fischfleischproteine wurden studiert. Die Ergebnisse bestätigten, dass die Proteine des Fisches ,,Meluha“ vom Gesichtspunkt der Ernährungskunde erstklassig sind. Infolge des während des Salzens eindiffundierenden Natriumchlorids ist jedoch der Aschengehalt verhältnismässig hoch. In dem Hydrolysat der Meluhaproteine sind alle essentiellen Aminosäuren gegenwärtig. Leucin und Isoleucin kommen in der grössten Menge vor, während die Konzentrationen an Threonin une Lysin die niedrigsten sind. Eine ähnliche Tendenz gelangt zur Geltung auch in der Menge der freien Aminosäuren. Threonin und Tryptophan sind jedoch im Extrakt des Fischfleisches nicht nachweisbar. Die Abwesenheit der Schimmelpilze ist kennzeichnend auf die Mikroflora des Meluha Fischfleisches. Die vorherrschenden Mikroorganismen sind die Bacillen, Mikrokokken und Hefen. The chemical composition and microbiological state of the salted fish „Meluha”, furthermore the composition of the essential and free aminoacids of fish proteins were studied. The results proved that the proteins of the fish „Meluha“ are of first-class quality from the aspect of dietetics. Owing to the sodium chloride introduced during the salting process is however the ash content relatively high. All essential aminoacids are present in the hydrolysate of the Meluha protein. Leucine and isoleucine are present in the greatest amount whereas the concentrations of threonine and lysine are the lowest. A similar tendency appears also in the amounts of free aminoacids. However, threonine and tryptophane cannot be detected in the extract of fish. The microflora of the fish Meluha is characterized by the absence of moulds, the prevailing microorganisms being present are bacuili, micrococci and yeasts

    Consistency, Amplitudes and Probabilities in Quantum Theory

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    Quantum theory is formulated as the only consistent way to manipulate probability amplitudes. The crucial ingredient is a consistency constraint: if there are two different ways to compute an amplitude the two answers must agree. This constraint is expressed in the form of functional equations the solution of which leads to the usual sum and product rules for amplitudes. A consequence is that the Schrodinger equation must be linear: non-linear variants of quantum mechanics are inconsistent. The physical interpretation of the theory is given in terms of a single natural rule. This rule, which does not itself involve probabilities, is used to obtain a proof of Born's statistical postulate. Thus, consistency leads to indeterminism. PACS: 03.65.Bz, 03.65.Ca.Comment: 23 pages, 3 figures (old version did not include the figures
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