1,959 research outputs found

    Implementation of analytical Hartree-Fock gradients for periodic systems

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    We describe the implementation of analytical Hartree-Fock gradients for periodic systems in the code CRYSTAL, emphasizing the technical aspects of this task. The code is now capable of calculating analytical derivatives with respect to nuclear coordinates for systems periodic in 0, 1, 2 and 3 dimensions (i.e. molecules, polymers, slabs and solids). Both closed-shell restricted and unrestricted Hartree-Fock gradients have been implemented. A comparison with numerical derivatives shows that the forces are highly accurate.Comment: accepted by Comp. Phys. Com

    Does counters’ responsibility end at the margin of the marginal utility? : Reflection on „The Marginal Utilities and Marginal Costs of Having Children” by PĂ©ter MihĂĄlyi

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    In his article published in the 2019/4 issue of the Public Finance Quarterly, PĂ©ter MihĂĄlyi argues that in Hungary, population reduction and aging cannot be significantly reduced within national frameworks, no matter how large the amount of money by which the state tries to reduce the individual costs of childbearing is. In contrast, on the one hand, this article points out that there are realistic options for reducing the gap between the number of children desired and the number of children actually delivered, and thereby significantly increasing the fertility rate. On the other hand, the article outlines a number of factors (emigration, high rates of childlessness) that should be taken into account when designing a model for the individual utility of childbearing, and thus give families additional aspects to consider when making decisions in terms of childbearing

    Measuring the Macroeconomic Performance of Public Finance Management

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    In international practice, the performance of public finance management is usually assessed on the basis of quality indicators of the subsystems of the public finance system. The experts of the State Audit Office of Hungary have developed an evaluation system capable of measuring the performance of public finance management on the basis of quantitative indicators and quantifying the contribution of the factors that determine performance most. This article describes this system. It also shows how the assessment system was used to analyse the risks to the ongoing reduction of Hungarian public debt

    Heat potential evaluation of effluent and used thermal waters in Budapest, Hungary

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    Europe’s largest thermal water system can be found in the capital of Hungary. The springs and wells that supply the famous baths of Budapest discharge mainly from a regional Triassic carbonate rock aquifer system. The springs have mostly been substituted by wells; only a few natural springs are known today, most of which are drained unused into the Danube. In this study, first the heat potential of these unutilized spring waters in the three natural discharge areas was assessed. Secondly, the heat potential of used thermal waters of three baths was calculated. At the springs discharge and temperature measurements were carried out. In the case of the baths, water management data were evaluated. At the BoltĂ­v Spring at the foot of RĂłzsadomb, the heat potential calculation shows that cooling the spring water to 5 °C would provide 6 MWth thermal capacity, providing a stable energy source for heat pumps. From the overflowing water of the springs of Rudas Bath at the foot of GellĂ©rt Hill, a total of 107 kWth heat could be utilized when cooling it to 5 °C, possibly by heat pump system. However, the heat potential of the BrĂŒndl Spring is not sufficient for geothermal utilization, mainly due to lack of end users in the vicinity of the spring. Together with the wastewater of the thermal baths, the effluent springs and wastewaters of pools carry a total of 25 MWth waste heat, which is a considerable amount compared to the needs of a public institution. The importance of this study is in the assessment of such potential heat sources (unused lukewarm and thermal springs, wastewater of spa pools) which are present either naturally or artificially, and do not require further thermal water production for heating purposes

    Real Space Approach to Electronic-Structure Calculations

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    We have applied the Finite Element Method to the self-consistent electronic structure calculations of molecules and solids for the first time. In this approach all the calculations are performed in "real space" and the use of non-uniform mesh is made possible, thus enabling us to deal with localized systems with ease. To illustrate the utility of this method, we perform an all-electron calculation of hydrogen molecule in a supercell with LDA approximation. Our method is also applicable to mesoscopic systems.Comment: 11 pages, LaTeX, 5 figures available on request from [email protected]

    Finding the optimum activation energy in DNA breathing dynamics: A Simulated Annealing approach

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    We demonstrate how the stochastic global optimization scheme of Simulated Annealing can be used to evaluate optimum parameters in the problem of DNA breathing dynamics. The breathing dynamics is followed in accordance with the stochastic Gillespie scheme with the denaturation zones in double stranded DNA studied as a single molecule time series. Simulated Annealing is used to find the optimum value of the activation energy for which the equilibrium bubble size distribution matches with a given value. It is demonstrated that the method overcomes even large noise in the input surrogate data.Comment: 9 pages, 4 figures, iop article package include

    Multiple solutions of coupled-cluster equations for PPP model of [10]annulene

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    Multiple (real) solutions of the CC equations (corresponding to the CCD, ACP and ACPQ methods) are studied for the PPP model of [10]annulene, C_{10}H_{10}. The long-range electrostatic interactions are represented either by the Mataga--Nishimoto potential, or Pople's R^{-1} potential. The multiple solutions are obtained in a quasi-random manner, by generating a pool of starting amplitudes and applying a standard CC iterative procedure combined with Pulay's DIIS method. Several unexpected features of these solutions are uncovered, including the switching between two CCD solutions when moving between the weakly and strongly correlated regime of the PPP model with Pople's potential.Comment: 5 pages, 4 figures, RevTeX

    Etikus Közgazdasågtan

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    Az etnikai hovatartozĂĄs szĂĄmbavĂ©teli lehetƑsĂ©gei Ă©s szĂŒksĂ©gessĂ©ge

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    Keveset tudunk arrĂłl, hogy a jĂłlĂ©ti Ă©s a szegĂ©nysĂ©g elleni intĂ©zkedĂ©sek, vagy akĂĄr a nevesĂ­tett „romaprogramok” milyen valĂłdi hatĂĄst gyakorolnak a cigĂĄnysĂĄg Ă©lethelyzetĂ©nek javĂ­tĂĄsĂĄra. MegfelelƑ felmĂ©rĂ©sek, nyilvĂĄntartĂĄsok hĂ­jĂĄn nem ĂĄllapĂ­thatĂł meg kellƑ pontossĂĄggal, hogy az intĂ©zkedĂ©sek, programok kedvezmĂ©nyezettjei között mekkora a romĂĄk arĂĄnya. A cikk kifejti azokat a cĂ©lszerƱsĂ©gi, jogi Ă©s politikai Ă©rveket, amelyek az etnikai jellegƱ adatok jogilag Ă©s szakmailag megfelelƑ szĂĄmbavĂ©tele mellett szĂłlnak. A szerzƑ rĂĄmutat, hogy e programok cĂ©lzottsĂĄgĂĄnak Ă©s eredmĂ©nyessĂ©gĂ©nek vizsgĂĄlatĂĄhoz ĂĄltalĂĄban elegendƑ a romĂĄk arĂĄnyĂĄnak megĂĄllapĂ­tĂĄsa a programok kĂŒlönbözƑ szakaszaiban, azaz nem szĂŒksĂ©ges szemĂ©lyenkĂ©nt nyilvĂĄntartani, hogy ki a roma nemzetisĂ©gƱ. A cikk bemutatja, milyen lehetƑsĂ©gei vannak az etnikumhoz tartozĂĄs szĂĄmbavĂ©telĂ©nek az ĂĄltalĂĄnos jĂłlĂ©ti intĂ©zkedĂ©sek, illetve a cĂ©lzott szegĂ©nysĂ©g elleni programok esetĂ©ben
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