1,560 research outputs found

    Forecasting the Yield Curve for the Euro Region

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    This paper compares the forecast precision of the Functional Signal plus Noise (FSN), the Dynamic Nelson-Siegel (DL), and a random walk model. The empirical results suggest that both outperform the random walk at short horizons (one-month) and that the the FSN model outperforms the DL at the one-month forecasting horizon. The conclusions provided in this paper are important for policy makers, fixed income portfolio managers, financial institutions and academics.

    Myopic Loss Aversion and House-Money Effect Overseas: an experimental approach

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    Recent literature has found two behavioral effects - house-money and myopic loss aversion (MLA) - in several experimental designs. We show that although we can find a house-money effect using survey methods this evidence disappears when we study investment decision within a multi-period investment experiment. Loss aversion is found to govern the risk-taking behavior of subjects in dynamic settings, overcoming the house-money effect. These results are robust to experiments conducted in two different countries, Spain and Brazil.

    Improving the performance of independent task assignment heuristics minmin, maxmin and mufferage

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    Cataloged from PDF version of article.MinMin, MaxMin, and Sufferage are constructive heuristics that are widely and successfully used in assigning independent tasks to processors in heterogeneous computing systems. All three heuristics are known to run in O(KN2) time in assigning N tasks to K processors. In this paper, we propose an algorithmic improvement that asymptotically decreases the running time complexity of MinMin to O(KN log N) without affecting its solution quality. Furthermore, we combine the newly proposed MinMin algorithm with MaxMin as well as Sufferage, obtaining two hybrid algorithms. The motivation behind the former hybrid algorithm is to address the drawback of MaxMin in solving problem instances with highly skewed cost distributions while also improving the running time performance of MaxMin. The latter hybrid algorithm improves the running time performance of Sufferage without degrading its solution quality. The proposed algorithms are easy to implement and we illustrate them through detailed pseudocodes. The experimental results over a large number of real-life data sets show that the proposed fast MinMin algorithm and the proposed hybrid algorithms perform significantly better than their traditional counterparts as well as more recent state-of-the-art assignment heuristics. For the large data sets used in the experiments, MinMin, MaxMin, and Sufferage, as well as recent state-of-the-art heuristics, require days, weeks, or even months to produce a solution, whereas all of the proposed algorithms produce solutions within only two or three minutes

    Comparison of research framing preferences and information use of state legislators and advocates involved in cancer control, United States, 2012–2013

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    INTRODUCTION: Evidence-based policy plays an important role in prevention of cancer and other chronic diseases. The needs of actors involved in policy decision-making should inform knowledge translation strategies. This study examines the differences between state legislators and advocates in how they seek and use information and what their preferences are for how research information is framed. METHODS: We conducted a cross-sectional comparison of survey responses by US advocates (n = 77) and state legislators (n = 265) working on issues related to cancer control. RESULTS: Advocates differed significantly from legislators on all demographic characteristics. Advocates reported seeking and using information more frequently than legislators, though legislators used legislative research bureaus more often (0.45 point difference, P = .004). Both legislators and advocates prioritized the presentation and timeliness of research information similarly but reported different preferences for source (information bias, information relevance, delivery of information by trusted person) of research information. Several differences between advocates and legislators were modified by participant age. CONCLUSION: Our study provides insights for development of knowledge translation strategies to enhance evidence-based policy making for cancer control that are tailored to state-level legislators and advocates. Additional research efforts should evaluate the effectiveness of such knowledge translation strategies, particularly among advocates

    Fast-ignition design transport studies: realistic electron source, integrated PIC-hydrodynamics, imposed magnetic fields

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    Transport modeling of idealized, cone-guided fast ignition targets indicates the severe challenge posed by fast-electron source divergence. The hybrid particle-in-cell [PIC] code Zuma is run in tandem with the radiation-hydrodynamics code Hydra to model fast-electron propagation, fuel heating, and thermonuclear burn. The fast electron source is based on a 3D explicit-PIC laser-plasma simulation with the PSC code. This shows a quasi two-temperature energy spectrum, and a divergent angle spectrum (average velocity-space polar angle of 52 degrees). Transport simulations with the PIC-based divergence do not ignite for > 1 MJ of fast-electron energy, for a modest 70 micron standoff distance from fast-electron injection to the dense fuel. However, artificially collimating the source gives an ignition energy of 132 kJ. To mitigate the divergence, we consider imposed axial magnetic fields. Uniform fields ~50 MG are sufficient to recover the artificially collimated ignition energy. Experiments at the Omega laser facility have generated fields of this magnitude by imploding a capsule in seed fields of 50-100 kG. Such imploded fields are however more compressed in the transport region than in the laser absorption region. When fast electrons encounter increasing field strength, magnetic mirroring can reflect a substantial fraction of them and reduce coupling to the fuel. A hollow magnetic pipe, which peaks at a finite radius, is presented as one field configuration which circumvents mirroring.Comment: 16 pages, 17 figures, submitted to Phys. Plasma

    Petawatt laser absorption bounded

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    The interaction of petawatt (1015 W10^{15}\ \mathrm{W}) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light ff, and even the range of ff is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that ff exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials

    Concentração e Inadimplência nas Carteiras de Empréstimos dos Bancos Brasileiros

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    This paper evaluates the loans market in Brazil in the 2003 to 2008 period. It measures diversification and nonperforming loans for Banks credit portfolios. We employ the credit risk bureau database, which classifies loans by sector and risk. Results show an increase in higher risk loans and diversification in low risk loans. The non-performing loans figures have shown a downward trend for most economic activities.

    The role of researchers in disseminating evidence to public health practice settings: A cross-sectional study

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    BACKGROUND: Evidence-based public health interventions, which research has demonstrated offer the most promise for improving the population’s health, are not always utilized in practice settings. The extent to which dissemination from researchers to public health practice settings occurs is not widely understood. This study examines the extent to which public health researchers in the United States are disseminating their research findings to local and state public health departments. METHODS: In a 2012, nationwide study, an online questionnaire was administered to 266 researchers from the National Institutes of Health, the Centers for Disease Control and Prevention, and universities to determine dissemination practices. Logistic regression analyses were used to examine the association between dissemination to state and/or local health departments and respondent characteristics, facilitators, and barriers to dissemination. RESULTS: Slightly over half of the respondents (58%) disseminated their findings to local and/or state health departments. After adjusting for other respondent characteristics, respondents were more likely to disseminate their findings to health departments if they worked for a university Prevention Research Center or the Centers for Disease Control and Prevention, or received their degree more than 20 years ago. Those who had ever worked in a practice or policy setting, those who thought dissemination was important to their own research and/or to the work of their unit/department, and those who had expectations set by their employers and/or funding agencies were more likely to disseminate after adjusting for work place, graduate degree and/or fellowship in public health, and the year the highest academic degree was received. CONCLUSIONS: There is still room for improvement in strengthening dissemination ties between researchers and public health practice settings, and decreasing the barriers researchers face during the dissemination process. Researchers could better utilize national programs or workshops, knowledge brokers, or opportunities provided through academic institutions to become more proficient in dissemination practices

    Phylogeography of Rattus norvegicus in the South Atlantic Ocean

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    Acknowledgments Funding for sample collection was provided by the Shackleton Scholarship Fund, Antarctic Research Trust, the Wyoming Biodiversity Institute, PVE/CAPES (Proposal 235453) and Fundação para a Ciência e a Tecnologia (SFRH/BPD/88854/2012). Thanks to Martin Collins, Andy Black, Darren Christie and the Government of South Georgia and South Sandwich Islands for the provision of samples from South Georgia, Annalea Beard for providing the rat sample from St Helena Island, Joaquim Tapisso, Rita Monarca and Ana Cerveira for samples from Portugal, and Emily Puckett for help validating South American SNP haplotypes. Funding for DNA sequencing was provided by Island LandCare, the University of Auckland. Thanks to two anonymous reviewers for the constructive comments.Peer reviewedPublisher PD
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