693 research outputs found

    Quantum Algorithm for Dynamic Programming Approach for DAGs. Applications for Zhegalkin Polynomial Evaluation and Some Problems on DAGs

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    In this paper, we present a quantum algorithm for dynamic programming approach for problems on directed acyclic graphs (DAGs). The running time of the algorithm is O(n^mlogn^)O(\sqrt{\hat{n}m}\log \hat{n}), and the running time of the best known deterministic algorithm is O(n+m)O(n+m), where nn is the number of vertices, n^\hat{n} is the number of vertices with at least one outgoing edge; mm is the number of edges. We show that we can solve problems that use OR, AND, NAND, MAX and MIN functions as the main transition steps. The approach is useful for a couple of problems. One of them is computing a Boolean formula that is represented by Zhegalkin polynomial, a Boolean circuit with shared input and non-constant depth evaluating. Another two are the single source longest paths search for weighted DAGs and the diameter search problem for unweighted DAGs.Comment: UCNC2019 Conference pape

    Climate threats to coastal infrastructure and sustainable development outcomes

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    Data availability: Data used in this study can be accessed at https://doi.org/10.5281/zenodo.10554713.Code availability: Code relevant to the analysis can be accessed at https://www.dropbox.com/scl/fi/tpjcxtl4j9m9ht0tl0ocq/NCLIM-23071599-code_final.zip?rlkey=ux7du7k4rkru352moob6quwwu&dl=0.Change history: 11 March 2024A Correction to this paper has been published: https://doi.org/10.1038/s41558-024-01974-8Acknowledgements: We acknowledge the Bangladesh Climate Change and Disaster Risk Management Team at the World Bank, in particular S. Kazi and I. Urrutia, for providing the synthetic household data and general support throughout the project. Any views expressed are not necessarily those of or endorsed by the World Bank. We also acknowledge support from the United Nations Office for Project Services (UNOPS), the Global Center on Adaptation (GCA), the Government of Bangladesh, and the Center for Environmental and Geographic Information Services (CEGIS) for assisting with access to data and in-country facilitation. We acknowledge imagery courtesy of the United Nations Sustainable Development Goals (https://www.un.org/sustainabledevelopment), although the content of this publication is not endorsed by the United Nations or its officials or the Member States.Climate hazards pose increasing threats to development outcomes across the world’s coastal regions by impacting infrastructure service delivery. Using a high-resolution dataset of 8.2 million households in Bangladesh’s coastal zone, we assess the extent to which infrastructure service disruptions induced by flood, cyclone and erosion hazards can thwart progress towards the Sustainable Development Goals (SDGs). Results show that climate hazards potentially threaten infrastructure service access to all households, with the poorest being disproportionately threatened in 69% of coastal subdistricts. Targeting adaptation to these climatic threats in one-third (33%) of the most vulnerable areas could help to safeguard 50–85% of achieved progress towards SDG 3, 4, 7, 8 and 13 indicators. These findings illustrate the potential of geospatial climate risk analyses, which incorporate direct household exposure and essential service access. Such high-resolution analyses are becoming feasible even in data-scarce parts of the world, helping decision-makers target and prioritize pro-poor development.Open access funding provided by Royal Institute of Technology

    A field-theoretic approach to the Wiener Sausage

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    The Wiener Sausage, the volume traced out by a sphere attached to a Brownian particle, is a classical problem in statistics and mathematical physics. Initially motivated by a range of field-theoretic, technical questions, we present a single loop renormalised perturbation theory of a stochastic process closely related to the Wiener Sausage, which, however, proves to be exact for the exponents and some amplitudes. The field-theoretic approach is particularly elegant and very enjoyable to see at work on such a classic problem. While we recover a number of known, classical results, the field-theoretic techniques deployed provide a particularly versatile framework, which allows easy calculation with different boundary conditions even of higher momenta and more complicated correlation functions. At the same time, we provide a highly instructive, non-trivial example for some of the technical particularities of the field-theoretic description of stochastic processes, such as excluded volume, lack of translational invariance and immobile particles. The aim of the present work is not to improve upon the well-established results for the Wiener Sausage, but to provide a field-theoretic approach to it, in order to gain a better understanding of the field-theoretic obstacles to overcome.Comment: 45 pages, 3 Figures, Springer styl

    Chemical Diversity and Complexity of Scotch Whisky as Revealed by High-Resolution Mass Spectrometry

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    Scotch Whisky is an important product, both culturally and economically. Chemically, Scotch Whisky is a complex mixture, which comprises thousands of compounds, the nature of which are largely unknown. Here, we present a thorough overview of the chemistry of Scotch Whisky as observed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Eighty-five whiskies, representing the majority of Scotch Whisky produced and sold, were analyzed by untargeted high-resolution mass spectrometry. Thousands of chemical formulae were assigned for each sample based on parts-per-billion mass accuracy of FT-ICR MS spectra. For the first time, isotopic fine structure analysis was used to confirm the assignment of high molecular weight CHOS species in Scotch Whisky. The assigned spectra were compared using a number of visualization techniques, including van Krevelen diagrams, double bond equivalence (DBE) plots, as well as heteroatomic compound class distributions. Additionally, multivariate analysis, including PCA and OPLS-DA, was used to interpret the data, with key compounds identified for discriminating between types of whisky (blend or malt) or maturation wood type. FT-ICR MS analysis of Scotch Whisky was shown to be of significant potential in further understanding of the complexity of mature spirit drinks and as a tool for investigating the chemistry of the maturation processes. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13361-016-1513-y) contains supplementary material, which is available to authorized users

    Ruminant Brucellosis in the Kafr El Sheikh Governorate of the Nile Delta, Egypt: Prevalence of a Neglected Zoonosis

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    Brucellosis is a zoonosis of mammals caused by bacteria of the genus Brucella. It is responsible for a vast global burden imposed on human health through disability and on animal productivity. In humans brucellosis causes a range of flu-like symptoms and chronic debilitating illness. In livestock brucellosis causes economic losses as a result of abortion, infertility and decreased milk production. The main routes for human infection are consumption of contaminated dairy products and contact with infected ruminants. The control of brucellosis in humans depends on its control in ruminants, for which accurate estimates of the frequency of infection are very useful, especially in areas with no previous frequency estimates. We studied the seroprevalence of brucellosis and its geographic distribution among domestic ruminants in one governorate of the Nile Delta region, Egypt. In the study area, the seroprevalence of ruminant brucellosis is very high and has probably increased considerably since the early 1990s. The disease is widespread but more concentrated around major animal markets. These findings question the efficacy of the control strategy in place and highlight the high infection risk for the animal and human populations of the area and the urgent need for an improved control strategy

    Study of the reaction e^{+}e^{-} -->J/psi\pi^{+}\pi^{-} via initial-state radiation at BaBar

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    We study the process e+eJ/ψπ+πe^+e^-\to J/\psi\pi^{+}\pi^{-} with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BaBar detector at center-of-mass energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454 fb1\mathrm{fb^{-1}}. We investigate the J/ψπ+πJ/\psi \pi^{+}\pi^{-} mass distribution in the region from 3.5 to 5.5 GeV/c2\mathrm{GeV/c^{2}}. Below 3.7 GeV/c2\mathrm{GeV/c^{2}} the ψ(2S)\psi(2S) signal dominates, and above 4 GeV/c2\mathrm{GeV/c^{2}} there is a significant peak due to the Y(4260). A fit to the data in the range 3.74 -- 5.50 GeV/c2\mathrm{GeV/c^{2}} yields a mass value 4244±54244 \pm 5 (stat) ±4 \pm 4 (syst)MeV/c2\mathrm{MeV/c^{2}} and a width value 11415+16114 ^{+16}_{-15} (stat)±7 \pm 7(syst)MeV\mathrm{MeV} for this state. We do not confirm the report from the Belle collaboration of a broad structure at 4.01 GeV/c2\mathrm{GeV/c^{2}}. In addition, we investigate the π+π\pi^{+}\pi^{-} system which results from Y(4260) decay

    A comparative study of four intensive care outcome prediction models in cardiac surgery patients

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    <p>Abstract</p> <p>Background</p> <p>Outcome prediction scoring systems are increasingly used in intensive care medicine, but most were not developed for use in cardiac surgery patients. We compared the performance of four intensive care outcome prediction scoring systems (Acute Physiology and Chronic Health Evaluation II [APACHE II], Simplified Acute Physiology Score II [SAPS II], Sequential Organ Failure Assessment [SOFA], and Cardiac Surgery Score [CASUS]) in patients after open heart surgery.</p> <p>Methods</p> <p>We prospectively included all consecutive adult patients who underwent open heart surgery and were admitted to the intensive care unit (ICU) between January 1<sup>st </sup>2007 and December 31<sup>st </sup>2008. Scores were calculated daily from ICU admission until discharge. The outcome measure was ICU mortality. The performance of the four scores was assessed by calibration and discrimination statistics. Derived variables (Mean- and Max- scores) were also evaluated.</p> <p>Results</p> <p>During the study period, 2801 patients (29.6% female) were included. Mean age was 66.9 ± 10.7 years and the ICU mortality rate was 5.2%. Calibration tests for SOFA and CASUS were reliable throughout (p-value not < 0.05), but there were significant differences between predicted and observed outcome for SAPS II (days 1, 2, 3 and 5) and APACHE II (days 2 and 3). CASUS, and its mean- and maximum-derivatives, discriminated better between survivors and non-survivors than the other scores throughout the study (area under curve ≥ 0.90). In order of best discrimination, CASUS was followed by SOFA, then SAPS II, and finally APACHE II. SAPS II and APACHE II derivatives had discrimination results that were superior to those of the SOFA derivatives.</p> <p>Conclusions</p> <p>CASUS and SOFA are reliable ICU mortality risk stratification models for cardiac surgery patients. SAPS II and APACHE II did not perform well in terms of calibration and discrimination statistics.</p
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