125,153 research outputs found
Spin-resolved photoemission from Pd(111)
No full textSchmiedeskamp B, Kessler B, Müller N, Schönhense G, Heinzmann U. Spin-resolved photoemission from Pd(111). Solid State Communications. 1988;65(7):665-670
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
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
Optimal bispectrum estimator and simulations of the CMB lensing-integrated Sachs Wolfe non-Gaussian signal
No full textWe present the tools to optimally extract the lensing-integrated Sachs Wolfe (L-ISW) bispectrum signal from future cosmic microwave background (CMB) data. We implemented two different methods to simulate the non-Gaussian CMB maps with the L-ISW signal: a non-perturbative method based on the FLINTS lensing code and the separable mode-expansion method. We implemented the Komatsu, Spergel, and Wandelt (KSW) optimal estimator analysis for the L-ISW bispectrum and tested it on the non-Gaussian simulations for realistic CMB experimental settings with an inhomogeneous sky coverage. We show that the estimator approaches the Cramer-Rao bound and that Wiener filtering the L-ISW simulations slightly improves the estimate of fNLL-ISW by ≤ 10%. For a realistic CMB experimental setting that accounts for anisotropic noise and masked sky, we show that the linear term of the estimator is highly correlated to the cubic term and it is necessary to recover the signal and the optimal error bars. We also show that the L-ISW bispectrum, if not correctly accounted for, yields an underestimation of the fNLlocal error bars of ≃ 4%. A joint analysis of the non-Gaussian shapes and/or L-ISW template subtraction is needed to recover unbiased results of the primordial non-Gaussian signal from ongoing and future CMB experiments
The local and distant Universe: stellar ages and H0
No full textThe ages of the oldest stellar objects in our galaxy provide an independent test of the current cosmological model as they give a lower limit to the age of the Universe. Recent accurate parallaxes by the Gaia space mission, accurate measurements of the metallicity of stars, via individual elemental abundances, and advances in the modelling of stellar evolution, provide new, higher-precision age estimates of the oldest stellar populations in the galaxy: globular clusters and very-low-metallicity stars. The constraints on the age of the Universe, t U , so obtained are determined from the local Universe and at late time. It is well known that local and early-Universe determinations of another cosmological parameter closely related to the age of the Universe, the Hubble constant H 0 , show a3 σ tension. In the standard cosmological model, ΛCDM, t U and H 0 are related by the matter density parameter Ω m,0 . We propose to combine local t U constraints with late-time Ω m,0 estimates in a ΛCDM framework, to obtain a low-redshift H 0 determination that does not rely on early Universe physics. A proof-of-principle of this approach with current data gives H 0 =71±2.8 (H 0 = 69.3 ± 2.7) km s -1 Mpc -1 from globular clusters (very-low-metallicity stars) with excellent prospects for improved constraints in the near future
Colored titanium oxides: From jewelry to biomedical applications
No full textTitanium surface properties are related to the presence on the metal surface of a nanometric TiO2 film. It is possible to modify the TiO2 film by different techniques, among which the most effective is anodic oxidation. By modulating the operating conditions-electrolytic solution, cell voltage, and current density-it is possible to obtain films of increasing thicknesses and different crystalline structure which correspond to enhanced properties. In particular, it is possible to tune the surface color increasing the film thickness from few nanometers up to few hundreds of nanometers. The colored oxides thus obtained find applications ranging from the world of architecture and jewelry to the biomedical context. Anodic oxidation was exploited by Pietro Pedeferri as a powerful painting technique that permits to visualize the infinitely small and complex world where nanotechnologies operate and let anodizing become art
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Ultrahigh Vacuum Optical Spectroscopy of Chemically Functionalized Graphene Nanoribbons
No full textWe show that Raman and photoluminescence spectroscopies carried out in an ultrahigh vacuum (UHV) environment are a quick and nondestructive tool for investigating the electronic and vibrational properties of air-sensitive materials. As
a showcase of this technique, experimental results of monolayers of chemically functionalized graphene nanoribbons on Au and silicon dioxide surfaces are presented. As functionalization routes we perform ionic and covalent functionalization by alkali metals and hydrogen, respectively. Samples prepared in this way cannot be probed using a standard optical spectroscopy experiment in ambient conditions because of their sensitivity to air and the need for controlled in-situ preparation. UHV optical spectroscopy is able to give valuable information on the orientation, the doping level, the defect concentration, and the luminescent properties of functionalized graphene nanoribbons
- …
