265 research outputs found

    PLATO: A Program Library for the Analysis of 4D Nonlinear Transverse Motion

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    The PLATO (Perturbative Lattice Analysis and Tracking tOols) program, a program library for analyzing four-dimensional betatronic motion in circular particle accelerators is presented. The routines included in this library provide both the resonant and the nonresonant perturbative series that approximate nonlinear motion (normal forms); standard numerical tools such as the Lyapunov exponent, frequency analysis and evaluation of the dynamic aperture are also available. To ensure the highest flexibility, the code is fully compatible with standard tracking programs commonly used in the accelerator physics community

    Towards a Statistical Physics of Human Mobility

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    In this paper, we extend some ideas of statistical physics to describe the properties of human mobility. From a physical point of view, we consider the statistical empirical laws of private cars mobility, taking advantage of a GPS database which contains a sampling of the individual trajectories of 2% of the whole vehicle population in an Italian region. Our aim is to discover possible "universal laws" that can be related to the dynamical cognitive features of individuals. Analyzing the empirical trip length distribution we study if the travel time can be used as universal cost function in a mesoscopic model of mobility. We discuss the implications of the elapsed times distribution between successive trips that shows an underlying Benford's law, and we study the rank distribution of the average visitation frequency to understand how people organize their daily agenda. We also propose simple stochastic models to suggest possible explanations of the empirical observations and we compare our results with analogous results on statistical properties of human mobility presented in the literature

    Algorithms for a Precise Determination of the Betatron Tune

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    In circular accelerators the precise knowledge of the betatron tune is of paramount importance both for routine operation and for theoretical investigations. The tune is measured by sampling the transverse position of the beam for N turns and by performing the FFT of the stored data. One can also evaluate it by computing the Average Phase Advance (APA) over N turns. These approaches have an intrinsic error proportional to 1/N. However, there are special cases where either a better precision or a faster measurement is desired. More efficient algorithms can be used, as those suggested by E.Asseo [1] and recently by J. Laskar [2]. They provide tune estimates by far more precise than those of a plain FFT, as discussed in Ref. [3]. Another important isssue is the effect of the finite resolution of the instrumentation used to measure the beam position. This introduces a noise and the frequency response of the beam is modified [4,5} thus reducing the precision by which the tune is determined. In Section 2 we recall the methods based on the APA approach. In Section 3 we introduce the FFT based methods and the estimate of the algorithms error as a function of N. In Section 4 we discuss the effect of noise

    Economic Uncertainty and Fertility in Europe: Narratives of the Future

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    Background: In the last decade fertility rates have declined in most European countries, and explanations have tended to focus on the rise of economic uncertainty after the Great Recession. The empirical demographic tradition operationalized the forces of economic uncertainty through objective indicators of individuals’ labor market situation; for example, holding a temporary contract or being unemployed. However, contemporary European fertility trends are not comprehensively captured by these traditional indicators and statistical models, because fertility decisions are not a mere “statistical shadow of the past”. Objective: We propose a novel framework on economic uncertainty and fertility. This framework proffers that the conceptualization and operationalization of economic uncertainty needs to take into account that people use works of imagination, producing their own “narrative of the future” – namely, imagined futures embedded in social elements and their interactions. Narratives of the future allow people to act according to or in spite of the uncertainty they face, irrespective of structural constraints and their subjective perceptions. Contribution: In this reflection we suggest that the focus of contemporary fertility studies should partly shift to assessing how people build their narratives of the future. To this end, we propose several methodological strategies to empirically assess the role of narratives for fertility decisions. Future studies should also take into account that personal narratives are shaped by the “shared narratives” produced by several agents of socialization, such as parents and peers, as well as by the narratives produced by the media and other powerful opinion formers

    Mitochondrial apurinic/apyrimidinic endonuclease 1 enhances mtDNA repair contributing to cell proliferation and mitochondrial integrity in early stages of hepatocellular carcinoma

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    Background: Hepatocellular carcinoma (HCC) is the leading cause of primary liver cancers. Surveillance of individuals at specific risk of developing HCC, early diagnostic markers, and new therapeutic approaches are essential to obtain a reduction in disease-related mortality. Apurinic/apyrimidinic endonuclease 1 (APE1) expression levels and its cytoplasmic localization have been reported to correlate with a lower degree of differentiation and shorter survival rate. The aim of this study is to fully investigate, for the first time, the role of the mitochondrial form of APE1 in HCC. Methods: As a study model, we analyzed samples from a cohort of patients diagnosed with HCC who underwent surgical resection. Mitochondrial APE1 content, expression levels of the mitochondrial import protein Mia40, and mtDNA damage of tumor tissue and distal non-tumor liver of each patient were analyzed. In parallel, we generated a stable HeLa clone for inducible silencing of endogenous APE1 and re-expression of the recombinant shRNA resistant mitochondrially targeted APE1 form (MTS-APE1). We evaluated mtDNA damage, cell growth, and mitochondrial respiration. Results: APE1's cytoplasmic positivity in Grades 1 and 2 HCC patients showed a significantly higher expression of mitochondrial APE1, which accounted for lower levels of mtDNA damage observed in the tumor tissue with respect to the distal area. In the contrast, the cytoplasmic positivity in Grade 3 was not associated with APE1's mitochondrial accumulation even when accounting for the higher number of mtDNA lesions measured. Loss of APE1 expression negatively affected mitochondrial respiration, cell viability, and proliferation as well as levels of mtDNA damage. Remarkably, the phenotype was efficiently rescued in MTS-APE1 clone, where APE1 is present only within the mitochondrial matrix. Conclusions: Our study confirms the prominent role of the mitochondrial form of APE1 in the early stages of HCC development and the relevance of the non-nuclear fraction of APE1 in the disease progression. We have also confirmed overexpression of Mia40 and the role of the MIA pathway in the APE1 import process. Based on our data, inhibition of the APE1 transport by blocking the MIA pathway could represent a new therapeutic approach for reducing mitochondrial metabolism by preventing the efficient repair of mtDNA

    ANALISIS INTERDEPENDENSI FOREIGN DIRECT INVESTMENT (FDI) DENGAN VARIABEL MAKRO EKONOMI

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    ABSTRAK Tujuan utama dari penelitian ini adalah untuk menganalisis interdependensi antara FDI dengan beberapa variabel yang lain, seperti PDB, Trade, Nilai Tukar, dan Tingkat bunga. Model VAR digunakan untuk menunjukkan pandangan yang komprehensif dari interdependensi ini. Hasil empiris menunjukkan bahwa melalui model VAR, interdependensi antara variabel FDI, PDB, Trade, Nilai Output Industri, Nilai Tukar dan Tingkat Suku Bunga telah diteliti dalam hubungan jangka panjang melalui kointegrasi vektor dan jangka pendek yang berdampak pada model VAR. Korelasi dinamis variabel telah diperoleh dengan analisis varian dan analisis respon impuls. Beberapa implikasi besar muncul dari hasil penelitian. Jika pemerintah Indonesia berkeinginan mendorong FDI dan pertumbuhan ekonomi, hal ini dapat dilakukan dengan output dan nilai tukar. Dalam jangka pendek maupun jangka panjang, keduanya sangat penting untuk stabilitas ekonomi. Kata Kunci : FDI, Pertumbuhan ekonomi, variabel makro dan model VARBanda Ace
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