666 research outputs found

    On the financial sustainability of earnings-related pension schemes with"pay-as-you-go"financing and the role of government indexed bonds

    Get PDF
    In this paper the authors reconsider the idea of an earnings-related pension system with reserves invested in indexed government bonds as a mechanism to both ensure financial sustainability and improve security. They start by reviewing the characterization of the sustainable rate of return of an earnings-related pension system with pay-as-you-go financing. The authors show that current proxies for the sustainable rate, including the Swedish"gyroscope,"are not stable and propose an alternative measure that depends on the growth of the buffer-stock and the pay-as-you-go asset. Using a simple one-sector macroeconomic model that embeds a notional account pension system they then show how GDP indexed government bonds, if combined with the right measure for the sustainable rate of return on contributions, could be used to generate a sustainable and secure earnings-related pension system, without becoming a fiscal burden. The proposal is particularly attractive for countries considering reforms to earnings-related systems that have accumulated a large implicit pension debt. In this case, the government bonds allow the financing of this debt in a transparent way. The proposed mechanism can also facilitate the transition to a fully-funded pension system when the government bonds are allowed to be traded.Economic Theory&Research,Technology Industry,Pensions&Retirement Systems,Economic Growth,Population Policies

    Különböző cardiovascularis kockázatú idős, hypertoniás betegek kezelési elveinek összehasonlítása a magyar és nemzetközi irányelvek alapján (2001–2015)

    Get PDF
    The aim of this review is to present recommendations of the currently valid Hungarian practice guidelines regarding antihypertensive therapy of the elderly and very elderly with different cardiovascular risk profiles, compare and contrast these with international guidelines, describe changes brought about by the past 15 years, and review the evidence behind. Hypertension treatment guidelines and relevant statements of the Hungarian and European Societies of Hypertension, of the Joint National Committee and American Heart Association were processed. The use of age-independent treatment threshold, goal blood pressure values, and the tendency towards more intensive control in co-morbidities conferring high cardiovascular risk were overcome by the upsurge of new evidence and the re-evaluation of previous clinical trial data. These lead to the introduction of age-specific and generally less stringent blood pressure targets in all regions compared. However, the guidelines currently in force still differ in terms of the attainable values in concomitant diabetes, chronic kidney disease or albuminuria, use of beta-blockers and the definition of elderly. Nevertheless, there is unanimous agreement that benefit from lowering of blood pressure under systolic 140 mmHg is not supported by evidence and further investigation is warranted to determine optimal treatment targets in the elderly, in the aged over 80 and specific elderly risk groups. Orv. Hetil., 2016, 157(7), 247-259

    Excitation spectra for Andreev billiards of box and disk geometries

    Get PDF
    We study Andreev billiards of box and disk geometries by matching the wave functions at the interface of the normal and the superconducting region using the exact solutions of the Bogoliubov-de Gennes equation. The mismatch in the Fermi wave numbers and the effective masses of the normal system and the superconductor, as well as the tunnel barrier at the interface are taken into account. A Weyl formula (for the smooth part of the counting function of the energy levels) is derived. The exact quantum mechanical calculations show equally spaced singularities in the density of states. Based on the Bohr-Sommerfeld quantization rule a semiclassical theory is proposed to understand these singularities. For disk geometries two kinds of states can be distinguished: states either contribute through whispering gallery modes or are Andreev states strongly coupled to the superconductor. Controlled by two relevant material, parameters, three kinds of energy spectra exist in disk geometry. The first is dominated by Andreev reflections, the second, by normal reflections in an annular disk geometry. In the third case the coherence length is much larger than the radius of the superconducting region, and the spectrum is identical to that of a full disk geometry

    rCUR: an R package for CUR matrix decomposition

    Get PDF
    BACKGROUND: Many methods for dimensionality reduction of large data sets such as those generated in microarray studies boil down to the Singular Value Decomposition (SVD). Although singular vectors associated with the largest singular values have strong optimality properties and can often be quite useful as a tool to summarize the data, they are linear combinations of up to all of the data points, and thus it is typically quite hard to interpret those vectors in terms of the application domain from which the data are drawn. Recently, an alternative dimensionality reduction paradigm, CUR matrix decompositions, has been proposed to address this problem and has been applied to genetic and internet data. CUR decompositions are low-rank matrix decompositions that are explicitly expressed in terms of a small number of actual columns and/or actual rows of the data matrix. Since they are constructed from actual data elements, CUR decompositions are interpretable by practitioners of the field from which the data are drawn. RESULTS: We present an implementation to perform CUR matrix decompositions, in the form of a freely available, open source R-package called rCUR. This package will help users to perform CUR-based analysis on large-scale data, such as those obtained from different high-throughput technologies, in an interactive and exploratory manner. We show two examples that illustrate how CUR-based techniques make it possible to reduce significantly the number of probes, while at the same time maintaining major trends in data and keeping the same classification accuracy. CONCLUSIONS: The package rCUR provides functions for the users to perform CUR-based matrix decompositions in the R environment. In gene expression studies, it gives an additional way of analysis of differential expression and discriminant gene selection based on the use of statistical leverage scores. These scores, which have been used historically in diagnostic regression analysis to identify outliers, can be used by rCUR to identify the most informative data points with respect to which to express the remaining data points

    Outline analysis of the grapevine (Vitis vinifera L.) berry shape by elliptic Fourier descriptors

    Get PDF
    Grapevine berry morphology is one of the most important features in table grape production. In this study, berry samples of 46 grapevine accessions were investigated for 3 consecutive years with elliptic Fourier descriptors (EFD) to evaluate shape diversity. Ten reference shapes obtained from the OIV descriptor list were involved and principal component (PC) scores summarizing the EFD's were statistically evaluated with Two way ANOVA and discriminant analysis. The cummulative contribution of the five principal components was 96.83 %. Two way ANOVA revealed that berry shape had high variability within the accessions and years. Based on the linear discriminant analysis, reference shapes were compared to those of the accessions and graphic reconstruction was carried out. OIV references were considered as unknown samples and grouped into the accession classes. Overall correct classification of the accessions into their group was 13.88 %. Our results showed that EFD together with reference shapes are a powerful method to discribe berry shape and possibly give the future basis of uvometric evaluation of grapevine cultivars

    GRA.LE.D. (GRApevine LEaf Digitalization) Software for the Detection and Graphic Reconstruction of Ampelometric Differences Between Vitis Leaves

    Get PDF
    Raster graphic ampelometric software was not exclusively developed for the estimation of leaf area,but also for the characterization of grapevine (Viti vinifera L.) leaves. The software was written in C++programming language, using the C++ Builder 2007 for Windows 95-XP and Linux operation systems. Ithandles desktop-scanned images. On the image analysed with the GRA.LE.D., the user has to determine11 points. These points are then connected and the distances between them calculated. The GRA.LE.D.software supports standard ampelometric measurements such as leaf area, angles between the veins andlengths of the veins. These measurements are recorded by the software and exported into plain ASCII textfiles for single or multiple samples. Twenty-two biometric data points of each leaf are identified by theGRA.LE.D. It presents the opportunity to statistically analyse experimental data, allows comparison ofcultivars and enables graphic reconstruction of leaves using the Microsoft Excel Chart Wizard. The GRA.LE.D. was thoroughly calibrated and compared to other widely used instruments and methods such asphoto-gravimetry, LiCor Li3100, WinDIAS2.0 and ImageTool. By comparison, the GRA.LE.D. presentedthe most accurate measurements of leaf area, but the LiCor Li3100 and the WinDIAS2.0 were faster, whilethe photo-gravimetric method proved to be the most time-consuming. The WinDIAS2.0 instrument wasthe least reliable. The GRA.LE.D. is uncomplicated, user-friendly, accurate, consistent, reliable and haswide practical application

    The mechanism of the reverse recovery-step, phosphate release, and actin activation of Dictyostelium myosin II.

    Get PDF
    The rate-limiting step of the myosin basal ATPase (i.e. in absence of actin) is assumed to be a post-hydrolysis swinging of the lever arm (reverse recovery step), that limits the subsequent rapid product release steps. However, direct experimental evidence for this assignment is lacking. To investigate the binding and the release of ADP and phosphate independently from the lever arm motion, two single tryptophan-containing motor domains of Dictyostelium myosin II were used. The single tryptophans of the W129+ and W501+ constructs are located at the entrance of the nucleotide binding pocket and near the lever arm, respectively. Kinetic experiments show that the rate-limiting step in the basal ATPase cycle is indeed the reverse recovery step, which is a slow equilibrium step (k(forward) = 0.05 s(-1), k(reverse) = 0.15 s(-1)) that precedes the phosphate release step. Actin directly activates the reverse recovery step, which becomes practically irreversible in the actin-bound form, triggering the power stroke. Even at low actin concentrations the power stroke occurs in the actin-attached states despite the low actin affinity of myosin in the pre-power stroke conformation
    corecore