1,721,025 research outputs found
Molecular dynamics simulation of the fragile glass former o-terphenile: a flexible molecule model. II collective dynamics.
No full textOrientational and induced contributions to the depolarized Rayleigh spectra of liquid and supercooled ortho-terphenyl.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Vibrational origin of the fast relaxation processes in molecular glass formers.
Full text linkWe study the interaction of the relaxation processes with the density
fluctuations by molecular dynamics simulation of a flexible
molecular model for o-terphenyl in the liquid and supercooled phases.
We find evidence, besides the structural
relaxation, of a secondary vibrational relaxation whose
characteristic time, few ps, is slightly temperature dependent.
This i) confirms the result by Monaco et al. (Phys. Rev. E,
62 (2000) 7595) of the vibrational nature of the fast relaxation
observed in Brillouin Light Scattering experiments in o-terphenyl;
and ii) poses a caveat on the interpretation of the BLS spectra
of molecular systems in terms of a purely center-of-mass dynamics
Ground-state clusters for short-range attractive and long-range repulsive potentials
No full textWe report calculations of the ground-state energies and geometries for clusters of different sizes (up to 80 particles), where individual particles interact simultaneously via a short-ranged attractive potential, modeled with a generalization of the Lennard-Jones potential, and a long-ranged repulsive Yukawa potential. We show that for specific choices of the parameters of the repulsive potential, the ground-state energy per particle has a minimum at a finite cluster size. For these values of the parameters in the thermodynamic limit, at low temperatures and small packing fractions, where clustering is favored and cluster-cluster interactions can be neglected, thermodynamically stable cluster phases can be formed. The analysis of the ground-state geometries shows that the spherical shape is marginally stable. In the majority of the studied cases, we find that above a certain size, ground-state clusters preferentially grow almost in one dimension
Follow-up in a long-term randomized trial with neoadjuvant chemotherapy for squamous cell cervical carcinoma
No full textObjective To assess the role of neoadjuvant chemotherapy to achieve radical surgery in a lamer number of patients with locally advanced/or bulky Stage 1B cervical carcinoma We conducted a trial to determine whether neoadjuvant chemotherapy would improve disease-free survival and overall survival in Stage IB-III cervical cancer Design Prospective randomized clinical study with long-term follow-up Setting Department of Gynecology. Pernatology and Child Health. II Faculty University of Rome "La Saptenza" Methods 288 patients with squamous cell carcinoma of the uterine cervix. FIGO Stage IB-IIIB were randomized to one of the following treatments three courses of neoadjuvant chemotherapy with cisplatin. vinerstine. bleomycin (NACT arm. n = 159). conventional surgery or exclusive radiotherapy (CONV arm. n = 129) There was no difference in as:e. FIGO stage, tumor size and lymph node involvement between the two groups (p = its) Two hundred and thirty-four patients in Stage IB-IIb (n = 129 NACT arm and n = 105 CONV arm) and 24 patients in Stan Ill (NACT arm) who proved to be chemosensitive underwent radical hysterectomy Six Stage III patients. non responders to chemotherapy. and 24 patients, Stage III of the CONV arm, underwent radiotherapy Follow-up extended for seven years. Results The study was performed on disease-free survival related to several prognostic factors age. FIGO stage, tumor size, grading, parametrial involvement, lymph node status and surgical margins Recurrence of disease occurred in 49 (32.1%) patients of the NACT arm (n = 153) and in 39 (37 1%) patients of the CONV arm (n = 105) Statistically significant differences in the recurrence of the disease were related to FIGO stage (p < 003). grading (p < 05), paremetrial involvement (p < 002) lymph node status (p < .0001) and tumor size (p < .002) No statistical significance was related to age and surgical margins (p = its) Disease-free and overall survival in the two groups were, respectively, 65 4% vs 53 5% (p = ns) and 704% 65 9% (p = ns
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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