338,506 research outputs found
Two-step excitation of Rb atoms on He nanodroplets
No full textWe present the first sequential laser excitation of atom-doped helium nanodroplets. Rubidium atoms on the surface of helium nanodroplets are selectively excited with a continuous wave laser to the 5(2)P(1/2) state so as not to desorb from the nanodroplets. From there they are excited by a laser pulse to the 5 2 D state; a laser-induced fluorescence (LIF) spectrum is recorded by monitoring the 6(2)P -> 5(2)S(1/2) emission. The LIF spectrum differs from that of the two-photon one-color direct excitation spectrum 5(2)D <- 5(2)S(1/2), indicating that the system does relax vibrationally during the lifetime of the 5(2)P(1/2) state. To model the LIF spectra we use calculated energy levels of the Rb atom as a function of its distance R from the center of the helium nanodroplet. The Franck-Condon factors of the resulting potential energy curves agree with the experimental spectra. In the future the 5(2)P(1/2) state can be used as a springboard to reach high-lying (2)S and (2)D states, and possibly create an artificial super-atom
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Searching for a New Role in East Asian Regionlization: Japanese Production Networks in the Electronics Industry
No full textThis paper will be published in Peter and J. Katzenstein and Takashi Shiraishi, eds. Remaking East Asia: Beyond Americanization and Japanization, Cornell University Press. Part 1 introduces a few conceptual building-blocks that we need to capture the interactions between international business organization and regionalization. Part 2 describes the growing dependence of Japan's electronics industry on Asia, and explores how Japanese electronics firms are searching for ways to expand and upgrade their regional production networks, with China as the main prize. Part 3 examines constraints to change. I highlight peculiar features of the Japanese network management model in East Asia that once may have reflected strength. But now these very same features have turned into systemic weaknesses, as they constrain the capacity of Japanese firms to cope with and shape East Asia's increasingly complex processes of regionalization. The chapter concludes with an illustrative example of how some Japanese electronics firms are seeking to turn around gradually their EAPNs, by developing strategic alliances with emerging new industry leaders in Asia, primarily from Greater China. Forthcoming as: "Searching for a New Role in East Asian Regionalization - Japanese Production Networks in the Electronics Industry", chapter 7, in: Peter and J. Katzenstein and Takashi Shiraishi, eds., Remaking East Asia: Beyond Americanization and Japanization, Cornell University Press.
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
One- and two-photon spectroscopy of highly excited states of alkali-metal atoms on helium nanodroplets
No full textAlkali-metal atoms captured on the surface of superfluid helium droplets are excited to high energies (approximate to 3 eV) by means of pulsed lasers, and their laser-induced-fluorescence spectra are recorded. We report on the one-photon excitation of the (n+1) p <- ns transition of K, Rb, and Cs (n=4, 5, and 6, respectively) and on the two-photon one-color excitation of the 5d <- 5s transition of Rb. Gated-photon-counting measurements are consistent with the relaxation rates of the bare atoms, hence consistent with the reasonable expectation that atoms quickly desorb from the droplet and droplet-induced relaxation need not be invoked. (C) 2010 American Institute of Physics
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Tagging of Biomedical Articles on CiteULike: A Comparison of User, Author and Professional Indexing
No full textThis paper examines the context of online indexing from the viewpoint of three different groups: users, authors, and professional indexers. User tags, author keywords and descriptors were collected from academic journal articles, which were both indexed in Pubmed and tagged on CiteULike, and analysed. Descriptive statistics, informetric measures, and thesaural term comparison shows that there are important differences in the use of keywords between the three groups in addition to similarities which can be used to enhance support for search and browse. While tags and author keywords were found that matched descriptors exactly, other terms which did not match but provided important expansion to the indexing lexicon were found. These additional terms could be used to enhance support for searching and browsing in article databases as well as to provide invaluable data for entry vocabulary and emergent terminology for regular updates to indexing systems. Additionally, the study suggests that tags support organisation by association to task, projects and subject while making important connections to traditional systems which classify into subject categories
Synthesis and biological evaluation of carbohydrate-mimetics as ligands for Siglecs
No full textSialic acid binding immunoglobulin-like lectins (Siglecs) play an important role in the mediation of cell-cell interactions as well as in the regulation of signaling pathways.
They are mainly expressed in the haematopoietic and immune system, with exception of Siglec-4, also called myelin-associated glycoprotein (MAG). It was identified as one of neurite outgrowth inhibitors, playing a crucial role in paraplegia, which is caused by injuries of the central nervous system (CNS) and especially young people suffer from these severe consequences as, for example, the loss of motor functions. The lack of repair of the injured nerve strands originates from the inhibitory environment for axon regeneration in the CNS. SpeciÞc inhibitory proteins, such as MAG block the regrowth of nerve roots. We identiÞed potent small molecule MAG antagonists modifies in the 2- and 5-position. Furthermore, we investigated new neuraminic acid derivatives modiÞed in the 4-position, and the inßuence of various structural modiÞcations on their kinetic and thermodynamic binding properties. In a next step we presented high affinity ligands, which were identified in second-site screenings and optimized them according to medicinal chemistry aspects. All ligands were elucidated with respect to their binding affinity as well as their kinetic and thermodynamic profile.
Siglec-2, also known as CD22, is involved in the regulation and survival of B-cells and has been successfully targeted in cell depletion therapies with antibody-based approaches. Sialic acid derivatives, already known to bind with high affinity to myelin-associated glycoprotein (MAG, Siglec-4), were screened for their binding affinity for CD22 by surface plasmon resonance. The best compound identified was further modified with various hydrophobic substituents at the 2-, 5-, and 9-positions of the sialic acid scaffold, leading to nanomolar derivatives. Furthermore, initial tests regarding drug-like properties of these antagonists demonstrate the required high plasma protein binding yet a lack of oral availability, although its distribution coefficient (log D) is in the required range.
Finally, we investigated a library of sialic acid mimetics with respect to binding towards another member of the Siglec family, namely Sialadhesin and discuss the influence of various structural moieties with regard to the arising selectivity towards these three proteins
Heinrich Wilhelm Ernst
No full textHeinrich Wilhelm Ernst (1812 - 1864) is even in these days mainly known as an author of two pieces for solo violin - The Last Rose of Summer and Der Erlkönig. Because of this the main part of this dissertation deals with Ernst's life, which was full of the mysteries - till the recent time we did not know even the exact date of birth. It is completed by the chapter about Ernst's violins and by the list of works known and lost
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