323,513 research outputs found
Interaction of Fe+ with the C-60 surface: A study about the feasibility of endohedral doping
No full textThe feasibility of endohedral iron doping of C-60 is studied using a mass selected ion beam to create an Fe+ beam with variable energy (60-380 eV, 1.2x10(-3) C) which is directed at a C-60 thin film. The surface is characterized by x-ray photoelectron spectroscopy, and oxidation of the samples is used to discriminate between Fe@C-60 and carbides. The fullerene cages are damaged during the irradiation, and participate in direct Fe-C bond formation. The reaction with oxygen indicates the absence of sizable amount of Fe@C-60. Comparison with reference samples composed of iron and damaged fullerene layers (by Ar+ irradiation) supports this interpretation. The experiment serves as a model study for the investigation of different metal-fullerene combinations. (C) 2004 American Institute of Physics
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
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
Emergent spatial patterns of competing benthic and pelagic algae in a river network: A parsimonious basin-scale modeling analysis
No full textAlgae, as primary producers in riverine ecosystems, are found in two distinct habitats: benthic and pelagic algae typically prevalent in shallow/small and deep/large streams, respectively. Over an entire river continuum, spatiotemporal patterns of the two algal communities reflect specificity in habitat preference determined by geomorphic structure, hydroclimatic controls, and spatiotemporal heterogeneity in nutrient loads from point- and diffuse-sources. By representing these complex interactions between geomorphic, hydrologic, geochemical, and ecological processes, we present here a new river-network-scale dynamic model (CnANDY) for pelagic (A) and benthic (B) algae competing for energy and one limiting nutrient (phosphorus, P). We used the urbanized Weser River Basin in Germany (7th-order; ~8.4 million population; ~46 K km2) as a case study and analyzed simulations for equilibrium mass and concentrations under steady median river discharge. We also examined P, A, and B spatial patterns in four sub-basins. We found an emerging pattern characterized by scaling of P and A concentrations over stream-order ω, whereas B concentration was described by three distinct phases. Furthermore, an abrupt algal regime shift occurred in intermediate streams from B dominance in ω≤3 to exclusive A presence in ω≥6. Modeled and long-term basin-scale monitored dissolved P concentrations matched well for ω>4, and with overlapping ranges in ω<3. Power-spectral analyses for the equilibrium P, A, and B mass distributions along hydrological flow paths showed stronger clustering compared to geomorphological attributes, and longer spatial autocorrelation distance for A compared to B. We discuss the implications of our findings for advancing hydro-ecological concepts, guiding monitoring, informing management of water quality, restoring aquatic habitat, and extending CnANDY model to other river basins
Ordovician metamorphism and plutonism in the Sierra de Quilmes metamorphic complex: Implications for the tectonic setting of the northern Sierras Pampeanas (NW Argentina)
No full textTowards unravelling the geodynamic setting of the northern Sierras Pampeanas (NW Argentina) we describe the tectonometamorphic and geochronologic evolution of sub-greenschist to granulite facies metamorphic sediments, granitoid plutons, and pegmatites in the Ordovician Sierra de Quilmes metamorphic complex. The protoliths of the metasediments are represented by a sequence of turbidites and minor calcsilicate rocks of the Neoproterozoic to Cambrian Puncoviscana Formation. The metamorphic complex consists of four zones including the (1) chlorite, (2) biotite-muscovite, (3) gamet-cordierite-sillimanite, and (4) orthopyroxene zones. Zones (3) and (4) show an increasing degree of anatexis, reaching large-scale diatexis in the orthopyroxene zone at P-T conditions exceeding similar to 800 degrees C and 600 MPa. At, or shortly after the metamorphic peak, the granitic to tonalitic Cafayate pluton intruded approximately along the boundary between anatectic and non-anatectic rocks. Retrograde near-isobaric cooling of the middle crust was accompanied by non-penetrative ductile shearing at granulite to amphibolite facies P-T conditions. Evidence for significant prograde deformation is absent in the Sierra de Quilmes metamorphic complex. Monazite and titanite U-Pb isotopic data constrain the metamorphic peak in migmatites and calcsilicate rocks to be at or slightly prior to similar to 470 Ma. Retrograde amphibolite facies mineral reactions led to continuous formation of monazite and titanite during slow cooling between similar to 470 Ma and 455 Ma (U-Pb data). The composite Cafayate pluton intruded over a time interval of several million years between similar to 477 Ma (Sm-Nd isochron) and similar to 460 Ma (monazite and titanite U-Pb isochron), followed by pegmatites. A younger group of pegmatites was emplaced in the country rocks at the end of the Ordovician (similar to 440 Ma, Rb-Sr mineral isochrons), postdating most of the retrograde shear zones. Resetting of the muscovite K-Ar and Ar-40-Ar-39 system in weakly deformed pegmatites and crystallisation of new muscovite in low-grade metamorphic sediments at similar to 400-416 Ma is attributed to minor late greenschist and sub-greenschist facies metamorphism and deformation. The massive Early Ordovician heat transfer, the absence of major prograde deformation, and subsequent, prolonged phases of non-penetrative deformation in the high-grade metamorphic zones during slow near-isobaric cooling contradict crustal thickening and continent collision models, as have been proposed for the southern Sierras Pampeanas. We suggest continuous or stepwise extensional tectonics in a back-arc or a mobile belt tectonic environment for the Ordovician Sierra de Quilmes, and the northern Sierras Pampeanas in general. An extensional setting of the northern Sierras Pampeanas in the Ordovician is in agreement with the coeval formation of marine extensional sediment basins in vicinity of the Sierras Pampeanas in northwestern Argentina and southern Bolivia. (c) 2005 Published by Elsevier B.V
Changes in the electronic structure of gold particles upon thiol adsorption as a function of the mean particle size
No full textWe studied the interaction of adsorbed thiol molecules with gold nanoparticles as a function of the mean particle size. The results obtained from MXPS (monochromated X-Ray Photoelectron Spectroscopy) measurements showed that attachment of the thiol sulfur headgroup onto the cluster surface leads to a positive binding energy shift in the Au 4f core-level. The absence of line width broadening upon adsorption indicates that these changes affect the whole particle and not only the particle surface, where the actual Au-S bond is located. The positive binding energy shift depends on the cluster size and increases with decreasing diameter. A maximum shift of 0.41 eV could be measured for the smallest particles (similar to 1 nm). The valence band exhibited positive binding energy shifts similar to the Au 4f core-levels, but smaller in absolute values. Changes in the valence band shape were interpreted as re-hybridization of Au 5d electrons due to the creation of Au-S bonds. Furthermore, we observed a disappearance of the Fermi edge upon thiol adsorption, which we attribute to a sulfur-induced metal-insulator-transition of the gold cluster. (c) 2005 Elsevier B.V. All rights reserved
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
Author's address:
No full textCan archives of audiovisual TV interviews be used to make authors more visible to students, and thereby reduce the learning gap between native and non-native language speakers in college classes? We examined students in a college course who learned about one scholar's ideas through watching an audiovisual TV interview (i.e., visible author format) and about another scholar's ideas through reading a formal text description (i.e., invisible author format). For the invisible author, native language speakers scored significantly higher than the non-native language speakers on a corresponding exam question (i.e., a cognitive measure), generated more words on the exam question (i.e., a motivational measure), and mentioned the author's name more often in answering the exam question (i.e., an affective measure). For the visible author, the groups did not differ on any of these measures. These findings provide evidence for the idea that making the author visible through audiovisual TV interviews can eliminate the learning gap between native and non-native language speakers. 3 Universities around the world serve students who are non-native speakers of th
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
- …
