2,129 research outputs found

    Estimation of Sex from the Talus in Prehistoric Native Americans

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    We present both a multivariate discriminant analysis and a univariate procedure to estimate sex from measures of the talus (length, width and height). Both methods are comparable in accuracy (about 85%), but the univariate procedure is preferred due to its simplicity

    De novo sequence assembly and characterization of the floral transcriptome in cross- and self-fertilizing plants

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    <p>Abstract</p> <p>Background</p> <p>The shift from cross-fertilization to predominant self-fertilization is among the most common evolutionary transitions in the reproductive biology of flowering plants. Increased inbreeding has important consequences for floral morphology, population genetic structure and genome evolution. The transition to selfing is usually characterized by a marked reduction in flower size and the loss of traits involved in pollinator attraction and the avoidance of self-fertilization. Here, we use short-read sequencing to assemble, <it>de novo</it>, the floral transcriptomes of three genotypes of <it>Eichhornia paniculata</it>, including an outcrosser and two genotypes from independently derived selfers, and a single genotype of the sister species <it>E. paradoxa</it>. By sequencing mRNA from tissues sampled at various stages of flower development, our goal was to sequence and assemble the floral transcriptome and identify differential patterns of gene expression.</p> <p>Results</p> <p>Our 24 Mbp assembly resulted in ~27,000 contigs that averaged ~900 bp in length. All four genotypes had highly correlated gene expression, but the three <it>E. paniculata </it>genotypes were more correlated with one another than each was to <it>E. paradoxa</it>. Our analysis identified 269 genes associated with floral development, 22 of which were differentially expressed in selfing lineages relative to the outcrosser. Many of the differentially expressed genes affect floral traits commonly altered in selfing plants and these represent a set of potential candidate genes for investigating the evolution of the selfing syndrome.</p> <p>Conclusions</p> <p>Our study is among the first to demonstrate the use of Illumina short read sequencing for <it>de novo </it>transcriptome assembly in non-model species, and the first to implement this technology for comparing floral transcriptomes in outcrossing and selfing plants.</p

    Understanding pregnancy planning in a low-income country setting: validation of the London measure of unplanned pregnancy in Malawi

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    This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: The London Measure of Unplanned Pregnancy (LMUP) is a new and psychometrically valid measure of pregnancy intention that was developed in the United Kingdom. An improved understanding of pregnancy intention in low-income countries, where unintended pregnancies are common and maternal and neonatal deaths are high, is necessary to inform policies to address the unmet need for family planning. To this end this research aimed to validate the LMUP for use in the Chichewa language in Malawi.Methods: Three Chichewa speakers translated the LMUP and one translation was agreed which was back-translated and pre-tested on five pregnant women using cognitive interviews. The measure was field tested with pregnant women who were recruited at antenatal clinics and data were analysed using classical test theory and hypothesis testing.Results: 125 women aged 15-43 (median 23), with parities of 1-8 (median 2) completed the Chichewa LMUP. There were no missing data. The full range of LMUP scores was captured. In terms of reliability, the scale was internally consistent (Cronbach's alpha = 0.78) and test-retest data from 70 women showed good stability (weighted Kappa 0.80). In terms of validity, hypothesis testing confirmed that unmarried women (p = 0.003), women who had four or more children alive (p = 0.0051) and women who were below 20 or over 29 (p = 0.0115) were all more likely to have unintended pregnancies. Principal component analysis showed that five of the six items loaded onto one factor, with a further item borderline. A sensitivity analysis to assess the effect of the removal of the weakest item of the scale showed slightly improved performance but as the LMUP was not significantly adversely affected by its inclusion we recommend retaining the six-item score.Conclusion: The Chichewa LMUP is a valid and reliable measure of pregnancy intention in Malawi and can now be used in research and/or surveillance. This is the first validation of this tool in a low-income country, helping to demonstrate that the concept of pregnancy planning is applicable in such a setting. Use of the Chichewa LMUP can enhance our understanding of pregnancy intention in Malawi, giving insight into the family planning services that are required to better meet women's needs and save lives. © 2013 Hall et al.; licensee BioMed Central Ltd.Dr Hall’s Wellcome Trust Research Training Fellowship, grant number 097268/Z/11/Z

    Evaluation of the London Measure of Unplanned Pregnancy in a United States population of women

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    Copyright @ 2012 Morof et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Objective: To evaluate the reliability and validity of the London Measure of Unplanned Pregnancy (a U.K.-developed measure of pregnancy intention), in English and Spanish translation, in a U.S. population of women. Methods: A psychometric evaluation study of the London Measure of Unplanned Pregnancy (LMUP), a six-item, self-completion paper measure was conducted with 346 women aged 15–45 who presented to San Francisco General Hospital for termination of pregnancy or antenatal care. Analyses of the two language versions were carried out separately. Reliability (internal consistency) was assessed using Cronbach’s alpha and item-total correlations. Test-retest reliability (stability) was assessed using weighted Kappa. Construct validity was assessed using principal components analysis and hypothesis testing. Results: Psychometric testing demonstrated that the LMUP was reliable and valid in both U.S. English (alpha = 0.78, all item-total correlations .0.20, weighted Kappa = 0.72, unidimensionality confirmed, hypotheses met) and Spanish translation (alpha = 0.84, all item-total correlations .0.20, weighted Kappa = 0.77, unidimensionality confirmed, hypotheses met). Conclusion: The LMUP was reliable and valid in U.S. English and Spanish translation and therefore may now be used with U.S. women.The study was funded by an anonymous donation

    Flipping quantum coins

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    Coin flipping is a cryptographic primitive in which two distrustful parties wish to generate a random bit in order to choose between two alternatives. This task is impossible to realize when it relies solely on the asynchronous exchange of classical bits: one dishonest player has complete control over the final outcome. It is only when coin flipping is supplemented with quantum communication that this problem can be alleviated, although partial bias remains. Unfortunately, practical systems are subject to loss of quantum data, which restores complete or nearly complete bias in previous protocols. We report herein on the first implementation of a quantum coin-flipping protocol that is impervious to loss. Moreover, in the presence of unavoidable experimental noise, we propose to use this protocol sequentially to implement many coin flips, which guarantees that a cheater unwillingly reveals asymptotically, through an increased error rate, how many outcomes have been fixed. Hence, we demonstrate for the first time the possibility of flipping coins in a realistic setting. Flipping quantum coins thereby joins quantum key distribution as one of the few currently practical applications of quantum communication. We anticipate our findings to be useful for various cryptographic protocols and other applications, such as an online casino, in which a possibly unlimited number of coin flips has to be performed and where each player is free to decide at any time whether to continue playing or not.Comment: 17 pages, 3 figure

    Improving the cost-effectiveness of visual devices for the control of Riverine tsetse flies, the major vectors of Human African Trypanosomiasis

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    Control of the Riverine (Palpalis) group of tsetse flies is normally achieved with stationary artificial devices such as traps or insecticide-treated targets. The efficiency of biconical traps (the standard control device), 161 m black targets and small 25625 cm targets with flanking nets was compared using electrocuting sampling methods. The work was done on Glossina tachinoides and G. palpalis gambiensis (Burkina Faso), G. fuscipes quanzensis (Democratic Republic of Congo), G. f. martinii (Tanzania) and G. f. fuscipes (Kenya). The killing effectiveness (measured as the catch per m2 of cloth) for small targets plus flanking nets is 5.5–15X greater than for 1 m2 targets and 8.6–37.5X greater than for biconical traps. This has important implications for the costs of control of the Riverine group of tsetse vectors of sleeping sickness

    Benchmarking factor selection and sensitivity: a case study with nursing courses

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    There is an increasing requirement in higher education (HE) worldwide to deliver excellence. Benchmarking is widely used for this purpose, but methodological approaches to the creation of benchmark metrics vary greatly. Approaches require selection of factors for inclusion and subsequent calculation of benchmarks for comparison. We describe an approach using machine learning to select input factors based on their value to predict completion rates of nursing courses. Data from over 36,000 students, from nine institutions over three years were included and weighted averages provided a dynamic baseline for year on year and within year comparisons between institutions. Anonymised outcomes highlight the variation in benchmarked performances between institutions and we demonstrate the value of accompanying sensitivity analyses. Our methods are appropriate worldwide, for many forms of data and at multiple scales of enquiry. We discuss our results in the context of HE management, highlighting the value of scrutinising benchmark calculations

    Information Causality as a Physical Principle

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    Quantum physics exhibits remarkable distinguishing characteristics. For example, it gives only probabilistic predictions (non-determinism) and does not allow copying of unknown state (no-cloning). Quantum correlations may be stronger than any classical ones, nevertheless information cannot be transmitted faster than light (no-signaling). However, all these features do not single out quantum physics. A broad class of theories exist which share such traits with quantum mechanics, while they allow even stronger than quantum correlations. Here, we introduce the principle of Information Causality. It states that information that Bob can gain about a previously completely unknown to him data set of Alice, by using all his local resources (which may be correlated with her resources) and a classical communication from her, is bounded by the information volume of the communication. In other words, if Alice communicates m bits to Bob, the total information access that Bob gains to her data is not greater than m. For m=0, Information Causality reduces to the standard no-signaling principle. We show that this new principle is respected both in classical and quantum physics, whereas it is violated by all the no-signaling correlations which are stronger that the strongest quantum correlations. Maximally strong no-signalling correlations would allow Bob access to any m bit subset of the whole data set held by Alice. If only one bit is sent by Alice (m=1), this is tantamount to Bob being able to access the value of any single bit of Alice's data (but of course not all of them). We suggest that Information Causality, a generalization of no-signaling, might be one of the foundational properties of Nature.Comment: This version of the paper is as close to the published one as legally possibl

    Measurements in two bases are sufficient for certifying high-dimensional entanglement

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    High-dimensional encoding of quantum information provides a promising method of transcending current limitations in quantum communication. One of the central challenges in the pursuit of such an approach is the certification of high-dimensional entanglement. In particular, it is desirable to do so without resorting to inefficient full state tomography. Here, we show how carefully constructed measurements in two bases (one of which is not orthonormal) can be used to faithfully and efficiently certify bipartite high-dimensional states and their entanglement for any physical platform. To showcase the practicality of this approach under realistic conditions, we put it to the test for photons entangled in their orbital angular momentum. In our experimental setup, we are able to verify 9-dimensional entanglement for a pair of photons on a 11-dimensional subspace each, at present the highest amount certified without any assumptions on the state.Comment: 11+14 pages, 2+7 figure

    Quantum teleportation between light and matter

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    Quantum teleportation is an important ingredient in distributed quantum networks, and can also serve as an elementary operation in quantum computers. Teleportation was first demonstrated as a transfer of a quantum state of light onto another light beam; later developments used optical relays and demonstrated entanglement swapping for continuous variables. The teleportation of a quantum state between two single material particles (trapped ions) has now also been achieved. Here we demonstrate teleportation between objects of a different nature - light and matter, which respectively represent 'flying' and 'stationary' media. A quantum state encoded in a light pulse is teleported onto a macroscopic object (an atomic ensemble containing 10^12 caesium atoms). Deterministic teleportation is achieved for sets of coherent states with mean photon number (n) up to a few hundred. The fidelities are 0.58+-0.02 for n=20 and 0.60+-0.02 for n=5 - higher than any classical state transfer can possibly achieve. Besides being of fundamental interest, teleportation using a macroscopic atomic ensemble is relevant for the practical implementation of a quantum repeater. An important factor for the implementation of quantum networks is the teleportation distance between transmitter and receiver; this is 0.5 metres in the present experiment. As our experiment uses propagating light to achieve the entanglement of light and atoms required for teleportation, the present approach should be scalable to longer distances.Comment: 23 pages, 8 figures, incl. supplementary informatio
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