422 research outputs found

    Changes in Social Structure, Class, and Stratification: The Polish Panel Survey (POLPAN)

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    We present an overview of the intellectual foundations and some major research questions and topics of the Polish Panel Survey (POLPAN). Carried out since 1988 in 5-year intervals, with the latest in 2013, POLPAN is the longest continuously run panel survey on changes in social structure, class and stratification in Central and Eastern Europe. The 2018 round is in planning. POLPAN is strongly anchored in recent theoretical innovations surrounding analyses of social structure and its change, as well as in the most up-to-date survey methodology. As such, POLPAN has major substantive and methodological contributions. Substantively, POLPAN constitutes a breakthrough that stems from taking into account individuals' life courses in a long time span. Methodologically, POLPAN enhances knowledge about how to conduct long-term panel studies and how to assess the quality of this type of data. Social scientists interested in the dynamics of social structure, class, and stratification, as well as political attitudes and behaviors, have a wealth of data with which to address timeless and timely research questions from a variety of perspectives and fields

    Ranked prediction of p53 targets using hidden variable dynamic modeling

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    Full exploitation of microarray data requires hidden information that cannot be extracted using current analysis methodologies. We present a new approach, hidden variable dynamic modeling (HVDM), which derives the hidden profile of a transcription factor from time series microarray data, and generates a ranked list of predicted targets. We applied HVDM to the p53 network, validating predictions experimentally using small interfering RNA. HVDM can be applied in many systems biology contexts to predict regulation of gene activity quantitatively

    Vascularization of the Selaginella rhizophore: anatomical fingerprints of polar auxin transport with implications for the deep fossil record

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138403/1/nph14478_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138403/2/nph14478-sup-0005-Legends.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138403/3/nph14478.pd

    The role of paleontological data in bryophyte systematics

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    Systematics reconstructs tempo and mode in biological evolution by resolving the phylogenetic fabric of biodiversity. The staggering duration and complexity of evolution, coupled with loss of information (extinction), render exhaustive reconstruction of the evolutionary history of life unattainable. Instead, we sample its products-phenotypes and genotypes-to generate phylogenetic hypotheses, which we sequentially reassess and update against new data. Current consensus in evolutionary biology emphasizes fossil integration in total-evidence analyses, requiring in-depth understanding of fossils-age, phenotypes, and systematic affinities-and a detailed morphological framework uniting fossil and extant taxa. Bryophytes present a special case: deep evolutionary history but sparse fossil record and phenotypic diversity encompassing small dimensional scales. We review how these peculiarities shape fossil inclusion in bryophyte systematics. Paucity of the bryophyte fossil record, driven primarily by phenotypic (small plant size) and ecological constraints (patchy substrate-hugging populations), and incomplete exploration, results in many morphologically isolated, taxonomically ambiguous fossil taxa. Nevertheless, instances of exquisite preservation and pioneering studies demonstrate the feasibility of including bryophyte fossils in evolutionary inference. Further progress will arise from developing extensive morphological matrices for bryophytes, continued exploration of the fossil record, re-evaluation of previously described fossils, and training specialists in identification and characterization of bryophyte fossils, and in bryophyte morphology. Unlocking the severely underutilized potential of the bryophyte fossil record for illuminating phylogeny, systematics, and evolution will require, aside from continued exploration, development of extensive morphological matrices and trained specialists.Peer reviewe

    Aggregatable Distributed Key Generation

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    In this paper, we introduce a distributed key generation (DKG) protocol with aggregatable and publicly-verifiable transcripts. Compared with prior publicly-verifiable approaches, our DKG reduces the size of the final transcript and the time to verify it from O(n2) to O(nlogn) , where n denotes the number of parties. As compared with prior non-publicly-verifiable approaches, our DKG leverages gossip rather than all-to-all communication to reduce verification and communication complexity. We also revisit existing DKG security definitions, which are quite strong, and propose new and natural relaxations. As a result, we can prove the security of our aggregatable DKG as well as that of several existing DKGs, including the popular Pedersen variant. We show that, under these new definitions, these existing DKGs can be used to yield secure threshold variants of popular cryptosystems such as El-Gamal encryption and BLS signatures. We also prove that our DKG can be securely combined with a new efficient verifiable unpredictable function (VUF), whose security we prove in the random oracle model. Finally, we experimentally evaluate our DKG and show that the per-party overheads scale linearly and are practical. For 64 parties, it takes 71 ms to share and 359 ms to verify the overall transcript, while for 8192 parties, it takes 8 s and 42.2 s respectively

    Integrative paleobotany: Affirming the role of fossils in modern plant biology - Introduction and dedication

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    If you are interested in plant evolution, try this quick exercise: take a phylogenetic tree of the plant kingdom, close your eyes, and point your finger randomly to a node of the phylogeny. Irrespective of the clade to which you are pointing, there is one thing you should know about it: the living representatives of that clade have evolved as a result of a long process in which failed attempts are the rule, and as a result, the diversity of extinct forms accumulated in the fossil record far exceeds that recorded in the extant flora. From this simple concept, Gar W. Rothwell made his career. Because of that, here is a second thing you should know about the plant clade to which you pointed at random: Gar has, more likely than not, contributed information about evolution in that clade at some point in his career. Gar was one of the principal contributors to the revival of paleobotany from a largely descriptive discipline to a vibrant field of investigation at the forefront of modern evolutionary sciences that contributes crucial insights into plant evolution, equal in importance to those provided by genetics and molecular biology. Because of this, the impact of Gar’s scientific contributions reaches far beyond the field of paleobotany, with important implications for wide areas of plant biology, including anatomy and morphology, development, systematics, phylogeny, and evolution. Gar earned a master’s degree in the laboratory of Thomas N. Taylor (University of Illinois at Chicago, 1966) studying Paleozoic seeds in the genus Conostoma (Rothwell and Eggert 1970; Rothwell 1971a). He subsequently earned his PhD degree in the laboratory of Wilson N. Stewart (University of Alberta, 1973), where he reconstructed the plants in the seed fern genus Callistophyton (Rothwell 1972b, 1975, 1980, 1981). His work was instrumental in ushering in studies of fossil plants as whole living organisms, looking at both structure and development. These early experiences launched Gar on a career in plant evolutionary biology that stretched over a half century, during which he occupied positions at the University of Alberta, University of London–Chelsea College, Ohio University, and Oregon State University. Throughout his career, Gar’s scholarly work and contributions have been recognized by numerous awards and honors: the Isabel Cookson Award, the Edgar T. Wherry Award, the Michael A. Cichan Award, the Merit Award of the Botanical Society of America, and honorary membership in the International Organization of Palaeobotany, where he served for 12 years as secretary-treasurer and president.Fil: Escapa, Ignacio Hernán. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tomescu, Alexandru M. F.. Humboldt State University. Department of Biological Sciences; Estados UnidosFil: Dunn, Michael T.. Cameron University. Department of Agriculture, Biology and Health Science; Estados UnidosFil: Stockey, Ruth A.. State University of Oregon; Estados Unido
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