763 research outputs found

    Non-Threshold Quantum Secret Sharing Schemes in the Graph State Formalism

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    In a recent work, Markham and Sanders have proposed a framework to study quantum secret sharing (QSS) schemes using graph states. This framework unified three classes of QSS protocols, namely, sharing classical secrets over private and public channels, and sharing quantum secrets. However, most work on secret sharing based on graph states focused on threshold schemes. In this paper, we focus on general access structures. We show how to realize a large class of arbitrary access structures using the graph state formalism. We show an equivalence between [[n,1]][[n,1]] binary quantum codes and graph state secret sharing schemes sharing one bit. We also establish a similar (but restricted) equivalence between a class of [[n,1]][[n,1]] Calderbank-Shor-Steane (CSS) codes and graph state QSS schemes sharing one qubit. With these results we are able to construct a large class of quantum secret sharing schemes with arbitrary access structures.Comment: LaTeX, 6 page

    News media coverage of euthanasia: A content analysis of Dutch national newspapers

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    © 2013 Rietjens et al.; licensee BioMed Central Ltd. 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 Netherlands is one of the few countries where euthanasia is legal under strict conditions. This study investigates whether Dutch newspaper articles use the term ‘euthanasia’ according to the legal definition and determines what arguments for and against euthanasia they contain. Methods: We did an electronic search of seven Dutch national newspapers between January 2009 and May 2010 and conducted a content analysis. Results: Of the 284 articles containing the term ‘euthanasia’, 24% referred to practices outside the scope of the law, mostly relating to the forgoing of life-prolonging treatments and assistance in suicide by others than physicians. Of the articles with euthanasia as the main topic, 36% described euthanasia in the context of a terminally ill patient, 24% for older persons, 16% for persons with dementia, and 9% for persons with a psychiatric disorder. The most frequent arguments for euthanasia included the importance of self-determination and the fact that euthanasia contributes to a good death. The most frequent arguments opposing euthanasia were that suffering should instead be alleviated by better care, that providing euthanasia can be disturbing, and that society should protect the vulnerable. Conclusions: Of the newspaper articles, 24% uses the term ‘euthanasia’ for practices that are outside the scope of the euthanasia law. Typically, the more unusual cases are discussed. This might lead to misunderstandings between citizens and physicians. Despite the Dutch legalisation of euthanasia, the debate about its acceptability and boundaries is ongoing and both sides of the debate are clearly represented

    Matroids and Quantum Secret Sharing Schemes

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    A secret sharing scheme is a cryptographic protocol to distribute a secret state in an encoded form among a group of players such that only authorized subsets of the players can reconstruct the secret. Classically, efficient secret sharing schemes have been shown to be induced by matroids. Furthermore, access structures of such schemes can be characterized by an excluded minor relation. No such relations are known for quantum secret sharing schemes. In this paper we take the first steps toward a matroidal characterization of quantum secret sharing schemes. In addition to providing a new perspective on quantum secret sharing schemes, this characterization has important benefits. While previous work has shown how to construct quantum secret sharing schemes for general access structures, these schemes are not claimed to be efficient. In this context the present results prove to be useful; they enable us to construct efficient quantum secret sharing schemes for many general access structures. More precisely, we show that an identically self-dual matroid that is representable over a finite field induces a pure state quantum secret sharing scheme with information rate one

    Avaliação de ensaios preliminares de linhagens de soja de primeiro ano.

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    bitstream/item/133858/1/ID13041-1984-1985sojaresultados-p14-28.pdfTrabalho apresentado na XIII Reunião de Pesquisa de Soja da Região Sul, Porto Alegre, 1984

    A transcriptomic approach for evaluating the relative potency and mechanism of action of azoles in the rat Whole Embryo Culture.

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    We evaluated the effect of six azoles on embryonic development in the rat whole embryo culture (WEC). Using the total morphological scoring system (TMS), we calculated the ID10concentration (effective dose for 10% decrease in TMS). For evaluating gene specific responses, we combined previously and newly collected transcriptomics data of rat WEC exposed to a total of twelve azoles at their ID10for 4h. Results revealed shared expressions responses in genes involved in the retinoic acid (RA) and sterol biosynthesis pathways, which are respectively representatives of developmental toxicity and targeted fungicidal action of the azoles. Azoles with more pronounced effects on the regulation of RA-associated genes were generally characterized as more potent embryotoxicants. Overall, compounds with strong sterol biosynthesis related responses and low RA related responses were considered as more favourable candidates, as they specifically regulated genes related to a desired target response. Among the identified sterol associated genes, we detected that methylsterol monooxygenase 1 (Msmo1) was more sensitively induced compared to Cyp51, a classical biomarker of this pathway. Therefore, we suggest that Msmo1 could be a better biomarker for screening the fungicidal value of azoles. In summary, we conclude that the embryonic regulation of RA and sterol metabolic pathways could be indicators for ranking azoles as embryotoxicants and determining their drug efficacy

    Avaliação intermediária e final de linhagens de soja.

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    bitstream/item/133857/1/ID13042-1984-1985sojaresultados-p43-47.pdfTrabalho apresentado na XIII Reunião de Pesquisa de Soja da Região Sul, Porto Alegre, 1984

    Evaluation of Human Interindividual Variation in Bioactivation of Estragole Using Physiologically Based Biokinetic Modeling

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    The present study investigates interindividual variation in liver levels of the proximate carcinogenic metabolite of estragole, 1′-hydroxyestragole, due to variation in two key metabolic reactions involved in the formation and detoxification of this metabolite, namely 1′-hydroxylation of estragole and oxidation of 1′-hydroxyestragole. Formation of 1′-hydroxyestragole is predominantly catalyzed by P450 1A2, 2A6, and 2E1, and results of the present study support that oxidation of 1′-hydroxyestragole is catalyzed by 17β-hydroxysteroid dehydrogenase type 2 (17β-HSD2). In a first approach, the study defines physiologically based biokinetic (PBBK) models for 14 individual human subjects, revealing a 1.8-fold interindividual variation in the area under the liver concentration-time curve (AUC) for 1′-hydroxyestragole within this group of human subjects. Variation in oxidation of 1′-hydroxyestragole by 17β-HSD2 was shown to result in larger effects than those caused by variation in P450 enzyme activity. In a second approach, a Monte Carlo simulation was performed to evaluate the extent of variation in liver levels of 1′-hydroxyestragole that could occur in the population as a whole. This analysis could be used to derive a chemical-specific adjustment factor (CSAF), which is defined as the 99th percentile divided by the 50th percentile of the predicted distribution of the AUC of 1′-hydroxyestragole in the liver. The CSAF was estimated to range between 1.6 and 4.0, depending on the level of variation that was taken into account for oxidation of 1′-hydroxyestragole. Comparison of the CSAF to the default uncertainty factor of 3.16 for human variability in biokinetics reveals that the default uncertainty factor adequately protects 99% of the populatio
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