691 research outputs found

    Micro-macro multilevel analysis for discrete data

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    Potential of lactic acid fermentation in reducing aflatoxin B1 in Tanzania maize-based gruel

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    Aflatoxins are toxic by-products of fungi, with harmful effects on human and animal health. Although maize is known to be highly susceptible to aflatoxin contamination, and a staple in many African countries, there is still lack of methods to mitigate the effects. The effect of lactic acid fermentation on reduction of aflatoxin B1 in Tanzania maize-based gruel (togwa) by four monocultures (Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus casei and Lactobacillus fermentum), natural fermentation and back-slopping at 30°C for up to 24 h was investigated. Monocultures removed 45–55% of aflatoxin B1 while natural fermentation and back-slopping removed 56% and 68% of aflatoxin B1, respectively. Thus, lactic acid fermentation could be a part of a comprehensive mycotoxicosis prevention strategy in the commonly consumed maize-based gruels. Consumers could benefit from enhanced food safety through consumption of gruel less contaminated with mycotoxins and might also benefit from the probiotic effects of lactic acid bacteria. In the scenario where lactic acid bacteria starter culture access and handling could prove challenging, especially to households and small-scale food processors in developing countries, the use of back-slopping in gruel fermentation might be advocated for in order to reduce aflatoxin B1.Keywords: aflatoxins, lactic acid fermentation, maize gruel, togwa, food safety, mycotoxins, East Afric

    Image transfer through a chaotic channel by intensity correlations

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    The three-wave mixing processes in a second-order nonlinear medium can be used for imaging protocols, in which an object field is injected into the nonlinear medium together with a reference field and an image field is generated. When the reference field is chaotic, the image field is also chaotic and does not carry any information about the object. We show that a clear image of the object be extracted from the chaotic image field by measuring the spatial intensity correlations between this field and one Fourier component of the reference. We experimentally verify this imaging protocol in the case of frequency downconversion.Comment: 17 pages, 7 figure

    Micro-macro multilevel latent class models with multiple discrete individual-level variables

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    An existing micro-macro method for a single individual-level variable is extended to the multivariate situation by presenting two multilevel latent class models in which multiple discrete individual-level variables are used to explain a group-level outcome. As in the univariate case, the individual-level data are summarized at the group-level by constructing a discrete latent variable at the group level and this group-level latent variable is used as a predictor for the group-level outcome. In the first extension, that is referred to as the Direct model, the multiple individual-level variables are directly used as indicators for the group-level latent variable. In the second extension, referred to as the Indirect model, the multiple individual-level variables are used to construct an individual-level latent variable that is used as an indicator for the group-level latent variable. This implies that the individual-level variables are used indirectly at the group-level. The within- and between components of the (co)varn the individual-level variables are independent in the Direct model, but dependent in the Indirect model. Both models are discussed and illustrated with an empirical data example

    Bichromatic Local Oscillator for Detection of Two-Mode Squeezed States of Light

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    We present a new technique for the detection of two-mode squeezed states of light that allows for a simple characterization of these quantum states. The usual detection scheme, based on heterodyne measurements, requires the use of a local oscillator with a frequency equal to the mean of the frequencies of the two modes of the squeezed field. As a result, unless the two modes are close in frequency, a high-frequency shot-noise-limited detection system is needed. We propose the use of a bichromatic field as the local oscillator in the heterodyne measurements. By the proper selection of the frequencies of the bichromatic field, it is possible to arbitrarily select the frequency around which the squeezing information is located, thus making it possible to use a low-bandwidth detection system and to move away from any excess noise present in the system.Comment: 11 pages, 3 figure

    A Bayesian analysis of classical shadows

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    The method of classical shadows heralds unprecedented opportunities for quantum estimation with limited measurements [H.-Y. Huang, R. Kueng, and J. Preskill, Nat. Phys. 16, 1050 (2020)]. Yet its relationship to established quantum tomographic approaches, particularly those based on likelihood models, remains unclear. In this article, we investigate classical shadows through the lens of Bayesian mean estimation (BME). In direct tests on numerical data, BME is found to attain significantly lower error on average, but classical shadows prove remarkably more accurate in specific situations -- such as high-fidelity ground truth states -- which are improbable in a fully uniform Hilbert space. We then introduce an observable-oriented pseudo-likelihood that successfully emulates the dimension-independence and state-specific optimality of classical shadows, but within a Bayesian framework that ensures only physical states. Our research reveals how classical shadows effect important departures from conventional thinking in quantum state estimation, as well as the utility of Bayesian methods for uncovering and formalizing statistical assumptions.Comment: 8 pages, 5 figure

    A Clinical Perspective on the Criteria for Liver Resection and the Use of Liver Function Tests

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    Ó The Author(s) 2009. This article is published with open access at Springerlink.com To the Editor, In a recently published survey of 100 liver centers, Breitenstein et al. [1] reported that on a global scale, (1) the average minimal remnant liver volume for resection is 25% (range = 15-40%) for normal liver parenchyma and 50% (range = 25–90%) for cirrhotic livers, (2) portal vein occlusion is employed in 89 % of the centers for purposes of augmenting liver volume before surgery, and that (3) 38 % of the centers employed liver function tests as part of their clinical routine, of which 76 % used the ICG clearance test. The interesting survey provoked a few issues that we feel obliged to address. The authors contend that ‘‘below a certain volume, a remnant liver cannot sustain metabolic, synthetic, and detoxifying functions’ ’ [1]—a statement that is unequivocal and uncontested. However, it should be born in mind that liver volume is not a directly proportional measure of liver function. We have demonstrated a few fundamental aspects of the volume-function relationship that support this notion: (i) Whereas liver function correlates with volume in uncompromised livers [2], there is significantly less correlation between liver volume an

    TISCC: A Surface Code Compiler and Resource Estimator for Trapped-Ion Processors

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    We introduce the Trapped-Ion Surface Code Compiler (TISCC), a software tool that generates circuits for a universal set of surface code patch operations in terms of a native trapped-ion gate set. To accomplish this, TISCC manages an internal representation of a trapped-ion system where a repeating pattern of trapping zones and junctions is arranged in an arbitrarily large rectangular grid. Surface code operations are compiled by instantiating surface code patches on the grid and using methods to generate transversal operations over data qubits, rounds of error correction over stabilizer plaquettes, and/or lattice surgery operations between neighboring patches. Beyond the implementation of a basic surface code instruction set, TISCC contains corner movement functionality and a patch translation that is implemented using ion movement alone. Except in the latter case, all TISCC functionality is extensible to alternative grid-like hardware architectures. TISCC output has been verified using the Oak Ridge Quasi-Clifford Simulator (ORQCS).Comment: 10 pages, 5 figures. Software to be released at https://github.com/ORNL-QCI/TISC

    Changes in income and employment after diagnosis among patients with multiple myeloma in The Netherlands

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    Objective: Due to new treatment options, survival rates in multiple myeloma (MM) are improving. Consequently, maintaining work and income is becoming more important for patients and society. Therefore, we aimed to explore the change in income and employment in patients with MM. Methods: Data from the Netherlands Cancer Registry of MM patients diagnosed between 2012 and 2017 were merged with socioeconomic data from Statistics Netherlands. Descriptive statistics were used to analyse total income, income from employment, and accumulated income before and after diagnosis. Results: Income from employment decreased by 45% in MM patients, between 1 year before and 4 years after diagnosis Four years after diagnosis, 35% of the patients were still employed, with an accumulated 5-year productivity loss of €121 million. Higher income loss from employment and job loss was observed in female patients, patients with more extensive disease, or those not treated with autologous stem cell transplant.Conclusion: Loss of (income from) employment among patients with MM was high, causing financial burden on the patient and society. With improving survival in MM, more research and awareness are needed to better assess the importance of income and work for MM patients and society.</p
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