983 resultados para bibliographic coupling
Resumo:
L'elaborato si impegna ad esporre i risultati derivanti da una revisione estensiva della letteratura riguardante le pratiche di misurazione della sostenibilità in azienda. Si è scelto un approccio al problema di impostazione bibliometrico, consistente in analisi statistiche di dati bibliografici ricavabili osservando le relazioni tra documenti. Si sono utilizzati strumenti di clustering per categorizzare la letteratura ed individuare le aree di maggior interesse potenziali per aziende che desiderino investire con successo nella sostenibilità. Come risultato, si è ottenuta una chiara identificazione delle principali tematiche che devono essere tenute in considerazione nell’affrontare valutazioni relative alla misurazione e valorizzazione dei concetti di sostenibilità e impatto ambientale in ambito aziendale. Il presente lavoro si presenta inoltre come guida metodologica per un approccio quantitativo alla revisione della letteratura, adattabile ed applicabile in maniera iterativa per un continuo monitoraggio del tema o per indagini in altri ambiti. Questa tesi si pone dunque come base per ricerche e analisi successive finalizzate alla comprensione della letteratura.
Resumo:
The title of the study is ''Toxicology Literature: An Informetric Analysis".In the field of Toxicology, the interdisciplinary research resulted in 'information fragmentation' of the basic subject to environmental, medical and economic toxicology. The interest in collaborative research resulted in the transdisciplinary growth of Toxicology which ultimately resulted in the scatter of literature.For the purpose of present study Toxicology is defined as the physical and chemical aspects of all poisons affecting environmental, economical and medical aspects of human life. Informetrics is "the use and development of a variety of measures to study and analyse several properties of information in general and documents in particular."The present study fled light on the main fields of Toxicology research as well as the important primary journals through which the results are being published. The authorshippattern, subject-wise scatter, country-wise, language-wise and growth pattern, self-citation, bibliographic coupling of the journals were studied. The study will be of great use in forrnulatinq the acquisition policy of documents in a library. The present study is useful in identifying obsolate journals so that they can be discarded from the collection
Resumo:
Introduction: This paper considers that information science (IS) literature covers a diversity of thematics with low emphasis on researches about conducting research. The study analyzes the scientific production of authors who investigate about research methodology in the information science (IS) literature, and the references used to lay the foundation of the methodological issues regarding the area. It discusses the methodological and epistemological positions of the leading researchers highlighted as the most productive investigators on the subject in the country. Method: The research adopts the content analysis coupled with metric studies to contextualize the indicators related to productivity, to the types of authorship and citation analysis. The bibliographic coupling method is considered an analysis mode which analyzes concomitant citations. It develops a theoretical framework about the importance of scientific production analysis in different knowledge fields. The study investigates, from a theoretical perspective, the concepts about research methodology and the complementarity between methodology and epistemology in conducting research. Results: The results of the analysis showed that the production of the highlighted authors presents the methodology as a thematic focus to be applied to IS contexts, as well as a research object in the field. The prominent productivity of the authors is justified especially by deepening the meta studies about the ways to conduct research in IS. This study also identifies a trend to single-authored studies about the theme. Conclusions: The research considers that meta studies and applied and methodological studies are important to recognize a consistent theoretical and practical core in the IS area. Regarding the epistemological influences identified by the citation analysis, the study observes that the critical rationalist epistemology and the social and political epistemology are highlighted in the construction of the theoretical framework of the most productive authors.
Resumo:
Although reciprocity is fundamental to all social orders, management research offers few reviews of the concept’s theoretical origins and current applications. To help bridge this gap, we elucidate the dominant understandings of reciprocity, ask which areas of research emerge from them, and explore how they interconnect. Our bibliometric methodology detects four clusters of management research on reciprocity. Across these clusters, authors subscribe mainly to substantialist ontology, marginalize morally oriented motives consistent with relational ontology, and largely assume that benefit-oriented motives underlie reciprocity. We outline the advantages of a moral-oriented relationalist concept of reciprocity and discuss potential areas for its development in management research.
Resumo:
A history of specialties in economics since the late 1950s is constructed on the basis of a large corpus of documents from economics journals. The production of this history relies on a combination of algorithmic methods that avoid subjective assessments of the boundaries of specialties: bibliographic coupling, automated community detection in dynamic networks, and text mining. These methods uncover a structuring of economics around recognizable specialties with some significant changes over the period covered (1956–2014). Among our results, especially noteworthy are (1) the clear-cut existence of ten families of specialties, (2) the disappearance in the late 1970s of a specialty focused on general economic theory, (3) the dispersal of the econometrics-centered specialty in the early 1990s and the ensuing importance of specific econometric methods for the identity of many specialties since the 1990s, and (4) the low level of specialization of individual economists throughout the period in contrast to physicists as early as the late 1960s.
Resumo:
A history of specialties in economics since the late 1950s is constructed on the basis of a large corpus of documents from economics journals. The production of this history relies on a combination of algorithmic methods that avoid subjective assessments of the boundaries of specialties: bibliographic coupling, automated community detection in dynamic networks and text mining. these methods uncover a structuring of economics around recognizable specialties with some significant changes over the time-period covered (1956-2014). Among our results, especially noteworthy are (a) the clearcut existence of 10 families of specialties, (b) the disappearance in the late 1970s of a specialty focused on general economic theory, (c) the dispersal of the econometrics-centered specialty in the early 1990s and the ensuing importance of specific econometric methods for the identity of many specialties since the 1990s, (d) the low level of specialization of individual economists throughout the period in contrast to physicists as early as the late 1960s.
Resumo:
We investigate synchronization in a Kuramoto-like model with nearest neighbor coupling. Upon analyzing the behavior of individual oscillators at the onset of complete synchronization, we show that the time interval between bursts in the time dependence of the frequencies of the oscillators exhibits universal scaling and blows up at the critical coupling strength. We also bring out a key mechanism that leads to phase locking. Finally, we deduce forms for the phases and frequencies at the onset of complete synchronization.
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Oscillator networks have been developed in order to perform specific tasks related to image processing. Here we analytically investigate the existence of synchronism in a pair of phase oscillators that are short-range dynamically coupled. Then, we use these analytical results to design a network able of detecting border of black-and-white figures. Each unit composing this network is a pair of such phase oscillators and is assigned to a pixel in the image. The couplings among the units forming the network are also dynamical. Border detection emerges from the network activity.
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We evaluate the mass of the B(s0) scalar meson and the coupling constant in the B(s0)BK vertex in the framework of QCD sum rules. We consider the B(s0) as a tetraquark state to evaluate its mass. We get m(Bs0) = (5.85 +/- 0.13) GeV, which is in agreement, considering the uncertainties, with predictions supposing it as a b (s) over bar state or a B (K) over bar bound state with J(P) = 0(+). To evaluate the g(Bs0BK) coupling, we use the three-point correlation functions of the vertex, considering B(s0) as a normal b (s) over bar state. The obtained coupling constant is: g(Bs0BK) = (16.3 +/- 3.2) GeV. This number is in agreement with light-cone QCD sum rules calculation. We have also compared the decay width of the B(s0) -> BK process considering the B(s0) to be a b (s) over bar state and a BK molecular state. The width obtained for the BK molecular state is twice as big as the width obtained for the b (s) over bar state. Therefore, we conclude that with the knowledge of the mass and the decay width of the B(s0) meson, one can discriminate between the different theoretical proposals for its structure.
Resumo:
We present Monte Carlo simulations for a molecular motor system found in virtually all eukaryotic cells, the acto-myosin motor system, composed of a group of organic macromolecules. Cell motors were mapped to an Ising-like model, where the interaction field is transmitted through a tropomyosin polymer chain. The presence of Ca(2+) induces tropomyosin to block or unblock binding sites of the myosin motor leading to its activation or deactivation. We used the Metropolis algorithm to find the transient and the equilibrium states of the acto-myosin system composed of solvent, actin, tropomyosin, troponin, Ca(2+), and myosin-S1 at a given temperature, including the spatial configuration of tropomyosin on the actin filament surface. Our model describes the short- and long-range cooperativity during actin-myosin binding which emerges from the bending stiffness of the tropomyosin complex. We found all transition rates between the states only using the interaction energy of the constituents. The agreement between our model and experimental data also supports the recent theory of flexible tropomyosin.
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We investigate the influence of couplings among continuum states in collisions of weakly bound nuclei. For this purpose, we compare cross sections for complete fusion, breakup, and elastic scattering evaluated by continuum discretized coupled channel (CDCC) calculations, including and not including these couplings. In our study, we discuss this influence in terms of the polarization potentials that reproduces the elastic wave function of the coupled channel method in single channel calculations. We find that the inclusion of couplings among continuum states renders the real part of the polarization potential more repulsive, whereas it leads to weaker absorption to the breakup channel. We show that the noninclusion of continuum-continuum couplings in CDCC calculations may lead to qualitative and quantitative wrong conclusions.
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Magnetoresistance measurements were performed on an n-type PbTe/PbEuTe quantum well and weak antilocalization effects were observed. This indicates the presence of spin orbit coupling phenomena and we showed that the Rashba effect is the main mechanism responsible for this spin orbit coupling. Using the model developed by Iordanskii et al., we fitted the experimental curves and obtained the inelastic and spin orbit scattering times. Thus we could compare the zero field energy spin-splitting predicted by the Rashba theory with the energy spin-splitting obtained from the analysis of the experimental curves. The final result confirms the theoretical prediction of strong Rashba effect on IV-VI based quantum wells.
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Using first-principles calculations it is demonstrated that Co doped graphenelike ZnO sheet presents ferromagnetic coupling. The Co atoms are energetically barrierless absorbed in the Zn sites, suffering a Jahn-Teller distortion. The results reveal that the origin of the ferromagnetic coupling, different from the bulk 3D ZnO stacking, is mainly guided by a direct exchange interaction without any additional defect. This ferromagnetic coupling is due to the system topology, namely, it is a direct consequence of the two-dimensional character of the ZnO monolayer within graphenelike structure. Increasing the number of ZnO layers the ferromagnetic coupling vanishes.
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Excitation functions of quasi-elastic scattering at backward angles have been measured for the (6,7)Li + (144)Sm systems at near-barrier energies, and fusion barrier distributions have been extracted from the first derivatives of the experimental cross sections with respect to the bombarding energies. The data have been analyzed in the framework of continuum discretized coupled-channel calculations, and the results have been obtained in terms of the influence exerted by the inclusion of different reaction channels, with emphasis on the role played by the projectile breakup.
Resumo:
A method to determine the effects of the geometry and lateral ordering on the electronic properties of an array of one-dimensional self-assembled quantum dots is discussed. A model that takes into account the valence-band anisotropic effective masses and strain effects must be used to describe the behavior of the photoluminescence emission, proposed as a clean tool for the characterization of dot anisotropy and/or inter-dot coupling. Under special growth conditions, such as substrate temperature and Arsenic background, 1D chains of In(0.4)Ga(0.6) As quantum dots were grown by molecular beam epitaxy. Grazing-incidence X-ray diffraction measurements directly evidence the strong strain anisotropy due to the formation of quantum dot chains, probed by polarization-resolved low-temperature photoluminescence. The results are in fair good agreement with the proposed model.