3,472 research outputs found
The Gallant-Lambert-Vanstone Decomposition Revisited
No full textThe Gallant-Lambert-Vanstone method accelerates the computation of scalar multiplication [k]P of a point (or a divisor) P of prime order r on some algebraic curve (or its Jacobian) by using an efficient endomorphism phi on such curve. Suppose phi has minimal polynomial h(x) = Sigma(d)(i=0) a(i)x(i) is an element of Z[x], the question how to efficiently decompose the scalar k as [k] P = Sigma(d-1)(i=0)[k(i)]phi(i) (P) with max(i) log vertical bar k(i)vertical bar approximate to 1/d log r has drawn a lot of attention. In this paper we show the link between the lattice based decomposition and the division in Z[phi] decomposition, and propose a hybrid method to decompose k with max(i) vertical bar k(i)vertical bar <= 2((d-5)/4) d(dN(h))((d-1)/2)r(1/d), where N(h) = Sigma(d-1)(i=0) a(i)(2). In particular, we give explicit and efficient GLV decompositions for some genus 1 and 2 curves with efficient endomorphisms through decomposing the Frobenius map in Z[phi], which also indicate that the complex multiplication usually implies good properties for GLV decomposition. Our results well support the GLV method for faster implementations of scalar multiplications on desired curves.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000345588100013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Computer Science, Theory & MethodsEICPCI-S(ISTP)
Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis
No full textBevier, Catherine R., Lambert, Max R., Andis Arietta, A. Z., Persons, Trevor B., Watkins-Colwell, Gregory J. (2022): Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis. Ichthyology & Herpetology 110 (3): 495-501, DOI: 10.1643/h2021133, URL: http://dx.doi.org/10.1643/h202113
A Transfer Report on the Development of a Framework to Evaluate Search Interfaces for their Support of Different User Types and Search Tactics
No full textAs the understanding of search systems, user needs and seeking strategies is developing, the design of search user interfaces is evolving to support more complicated and exploratory forms of search. With the design of new search features that enable these richer modes of exploration, comes the need to better understand the support they provide. In this report a new evaluation framework is presented that analyses search features for how they a) contribute to an overall interface, b) allow users to carry out different search tactics, and c) support different types of users and their needs. The novel contributions of the framework improve on some of the limitations of typical user studies, and allow search systems to be systematically analysed in much more detail and in much less time. The presented evaluation framework is then validated in three ways. First the validity of the models used as the building blocks of the framework are investigated through related work. Second the method of integrating these building-block models is validated and strengthened by consensus of expert opinion. Third, the overall approach is validated by comparing its analyses to the results of previously carried out user studies. The validation process has shown both the value of the framework and identified areas of future work that should be addressed for the framework to be completed. This report concludes with the set of contributions that the framework makes, and why the remaining work will be challenging, but critical to the final design
FIG. 4 in Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis
No full textFIG. 4. Total length of Mink Frog larvae reared in our current study (Mercer origin) and from published data from Hedeen (1971) in Minnesota (Deming Lake, East Twin Lake, Wilderness Drive Ditches).Published as part of Bevier, Catherine R., Lambert, Max R., Andis Arietta, A. Z., Persons, Trevor B. & Watkins-Colwell, Gregory J., 2022, Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis, pp. 495-501 in Ichthyology & Herpetology 110 (3) on page 499, DOI: 10.1643/h2021133, http://zenodo.org/record/784694
Die Bestimmung von Forschungsthemen in Max-Planck-Instituten im Spannungsfeld wissenschaftlicher und außerwissenschaftlicher Interessen: Ein Forschungsbericht
No full textHeute steht im Zentrum der öffentlichen Diskussion die Frage, wie sich der praktische Nutzen der Wissenschaft für Wirtschaft und Gesellschaft maximieren lässt. Die empirische Untersuchung, deren Ergebnisse in diesem Bericht dargestellt werden, geht von der umgekehrten Frage aus: Wie beeinflusst die gesellschaftliche Einbettung von Forschungseinrichtungen, vermittelt über die Auswahl von Forschungsthemen, die Entwicklung der Wissenschaft? Gegenstand der Untersuchung waren Institute der Max-Planck-Gesellschaft. Zunächst wurden statistische Daten über die Außenbeziehungen von Max-Planck-Instituten, die die Generalverwaltung der MPG zur Verfügung stellte, analysiert. In den Jahren 1999 und 2000 führte die Verfasserin Interviews mit den Direktoren ausgewählter Institute aller drei Sektionen der MPG durch und wertete verfügbare schriftliche Unterlagen über ihre Forschungstätigkeit aus. Der Bericht schildert exemplarisch den Prozess der Bestimmung von Forschungsthemen in Max-Planck-Instituten und wie dieser vom institutionellen Rahmen, von den Beziehungen zur wissenschaftlichen Fachwelt und von den Beziehungen zu verschiedenen Praxisfeldern beeinflusst wird. In Abhängigkeit von der Eigenart der Forschungsfelder, in denen ein Institut tätig ist, und dessen potentieller Praxisrelevanz ergeben sich verschiedene Muster von Außenbeziehungen, in denen je nachdem die Beziehungen zur Praxis oder die Beziehungen zur wissenschaftlichen Fachwelt größere Bedeutung für die Themenwahl haben.Today the usefulness of science for society and economy is the focal issue in science policy. This report presents the results of an empirical study starting from a different perspective, i.e. how the societal embeddedness of research institutions affects the choice of research topics and thus, in the aggregate, the direction of scientific development. In this study, Max Planck institutes were the object of investigation. In a first phase, statistical data about the external relations of Max Planck institutes were analyzed. In 1999 and 2000, this was followed by a series of interviews which the author conducted with the directors of selected institutes, supplemented by the analysis of written documents. The report shows in an exemplary fashion how the process of choosing research topics in Max Planck institutes is affected by their institutional shape, their interaction with different fields of societal praxis, and their relations to the national and international scientific communities. The resulting patterns of external relations and the relative importance of links with the scientific community and of links with fields of (e.g. industrial, medical) praxis differ according to the potential applicability of given research fields
A review of occupation-based social classifications for social research
No full textThis working paper is a review of issues associated with measuring occupations and using occupation-based socio-economic classifications in social science research. The review is orientated towards researchers who undertake secondary analyses of large scale micro-level social science datasets. The paper begins with an outline of how to handle raw occupational information. This is followed by an introduction to the two main approaches to measuring occupations, and a third lesser known but intellectually innovative approach. The three approaches are social class schemes, social stratification scales and the microclass approach. International comparisons are briefly described and a discussion of intersectionality with other key variables such as age and gender is provided. We are careful to emphasise that we are not advocating the uncritical adoption of any one particular socio-economic measure over and above other alternatives. Rather we are advocating that researchers should choose from the portfolio of existing socio-economic measures in an informed and empirically defensible way and we strongly advocate undertaking sensitivity analyses. We conclude that researchers should always use existing socio-economic measures that have agreed upon and well documented standards. We strongly advise researchers not to develop their own measures without strong justification, nor to use existing measures in an un-prescribed or ad hoc manner
FIG. 2 in Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis
No full textFIG. 2. Images of preserved specimens of Rana septentrionalis (YPM HERA 19716, 19699, 19701, 19704, 19711, 19712, 19694, 19696, 19718 [last four, part of a composite lot]) developmental series (top) from embryos to Gosner stage 42 and co-occurring ranid larvae (bottom, left to right) of Rana sylVatica (YPM HERA 10322), Rana clamitans (YPM HERA 10681), Rana palustris (YPM HERA 11412), and Rana catesbeiana (YPM HERA 13053). The scale bar is 1 cm. Large images of specimens of R. septentrionalis are provided in the Supplemental Materials (see Data Accessibility). Photos by A. Arietta courtesy of Yale Peabody Museum.Published as part of Bevier, Catherine R., Lambert, Max R., Andis Arietta, A. Z., Persons, Trevor B. & Watkins-Colwell, Gregory J., 2022, Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis, pp. 495-501 in Ichthyology & Herpetology 110 (3) on page 498, DOI: 10.1643/h2021133, http://zenodo.org/record/784694
Identification of a chlorodibenzo-p-dioxin dechlorinating Dehalococcoides mccartyi by stable isotope probing
No full textPolychlorinated dibenzo-p-dioxins (PCDDs) are released into the environment from a variety of both anthropogenic and natural sources. While highly chlorinated dibenzo-p-dioxins are persistent under oxic conditions, in anoxic environments these organohalogens can be reductively dechlorinated to less chlorinated compounds that are then more amenable to subsequent aerobic degradation. Identifying the microorganisms responsible for dechlorination is an important step in developing bioremediation approaches. In this study, we demonstrated the use of a DNA-stable isotope probing (SIP) approach to identify the bacteria active in dechlorination of PCDDs in river sediments, with 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD) as a model. In addition, pyrosequencing of reverse transcribed 16S rRNA of TeCDD dechlorinating enrichment cultures was used to reveal active members of the bacterial community. A set of operational taxonomic units (OTUs) responded positively to the addition of 1,2,3,4-TeCDD in SIP microcosms assimilating 13C-acetate as the carbon source. Analysis of bacterial community profiles of the 13C labeled heavy DNA fraction revealed that an OTU corresponding to Dehalococcoides mccartyi accounted for a significantly greater abundance in cultures amended with 1,2,3,4-TeCDD than in cultures without 1,2,3,4-TeCDD. This implies the involvement of this Dehalococcoides mccartyi strain in the reductive dechlorination of 1,2,3,4-TeCDD, and suggests the applicability of SIP for a robust assessment of the bioremediation potential of organohalogen contaminated sites.Peer reviewe
Optimal solution of the nearest correlation matrix problem by minimization of the maximum norm
No full textThe nearest correlation matrix problem is to find a valid (positive semidefinite) correlation matrix, R(m,m), that is nearest to a given invalid (negative semidefinite) or pseudo-correlation matrix, Q(m,m); m larger than 2. In the literature on this problem, 'nearest' is invariably defined in the sense of the least Frobenius norm. Research works of Rebonato and Jaeckel (1999), Higham (2002), Anjos et al. (2003), Grubisic and Pietersz (2004), Pietersz, and Groenen (2004), etc. use Frobenius norm explicitly or implicitly. However, it is not necessary to define 'nearest' in this conventional sense. The thrust of this paper is to define 'nearest' in the sense of the least maximum norm (LMN) of the deviation matrix (R-Q), and to obtain R nearest to Q. The LMN provides the overall minimum range of deviation of the elements of R from those of Q. We also append a computer program (source codes in FORTRAN) to find the LMN R from a given Q. Presently we use the random walk search method for optimization. However, we suggest that more efficient methods based on the Genetic algorithms may replace the random walk algorithm of optimization.Nearest correlation matrix problem; Frobenius norm; maximum norm; LMN correlation matrix; positive semidefinite; negative semidefinite; positive definite; random walk algorithm; Genetic algorithm; computer program; source codes; FORTRAN; simulation
FIG. 1 in Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis
No full textFIG. 1. (A–D) Egg masses of Rana septentrionalis. (A) Aquarium breeding set-up showing foam board and screening with a newly deposited egg mass (photo by G. Watkins-Colwell). (B) Egg mass of Rana septentrionalis in a plastic container (photo copyright D. Patrick). (C) Egg mass of Rana septentrionalis in situ in Aroostook County, Maine (photo by T. Persons). (D) Egg mass from captive-bred Group B (YPM HERA 019717, photo by A. Arietta courtesy of Yale Peabody Museum).Published as part of Bevier, Catherine R., Lambert, Max R., Andis Arietta, A. Z., Persons, Trevor B. & Watkins-Colwell, Gregory J., 2022, Early Life of the Mink Frog (Rana septentrionalis): From Fertilization to Metamorphosis, pp. 495-501 in Ichthyology & Herpetology 110 (3) on page 497, DOI: 10.1643/h2021133, http://zenodo.org/record/784694
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