Rerum cognoscere causas: part I - How do the ideas of system dynamics relate to traditional social theories and the voluntarism/determinism debate?

This is the first half of a two-part paper which deals with the social theoretic assumptions underlying system dynamics. The motivation is that clarification in this area can help mainstream social scientists to understand how our field relates to their literature, methods and concerns. Part I has two main sections. The aim of the first is to answer the question: How do the ideas of system dynamics relate to traditional social theories? The theoretic assumptions of the field are seldom explicit but rather are implicit in its practice. The range of system dynamics practice is therefore considered and related to a framework - widely used in both operational research (OR) and systems science - that organises the assumptions behind traditional social theoretic paradigms. Distinct and surprisingly varied groupings of practice are identified, making it difficult to place system dynamics in any one paradigm with any certainty. The difficulties of establishing a social theoretic home for system dynamics are exemplified in the second main section. This is done by considering the question: Is system dynamics deterministic? An analysis shows that attempts to relate system dynamics to strict notions of voluntarism or determinism quickly indicate that the field does not fit with either pole of this dichotomous, and strictly paradigmatic, view. Part I therefore concludes that definitively placing system dynamics with respect to traditional social theories is highly problematic. The scene is therefore set for Part II of the paper, which proposes an innovative and potentially fruitful resolution to this problem.

Decays of new nuclides and isomers beyond the proton drip line — the influence of neutron configurations

The energy of the vh9/2 orbital in nuclei above N = 82 drops rapidly in energy relative to the vf7/2 orbital as the occupancy of the πh11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161Os and 157W, and studied the decays of the proton emitter 160Re in detail. The 161Os and 160Re nuclei were produced in reactions of 290, 300 and 310 MeV 58Ni ions with an isotopically enriched 106Cd target, separated in‐flight using the RITU separator and implanted into the GREAT spectrometer. The 161Os α a decays populated the new nuclide 157W, which decayed by β‐particle emission. The β decay fed the known α‐decaying 1/2+ and 11/2− states in 157Ta, which is consistent with a vf7/2 ground state in 157W. The measured α‐decay energy and half‐life for 161Os correspond to a reduced α‐decay width that is compatible with s‐wave α‐particle emission, implying that its ground state is also a vf7/2 state. Over 7000 160Re nuclei were produced and the γ decays of a new isomeric state feeding the πd3/2 level in 160Re were discovered, but no evidence for the proton or a decay of the expected πh11/2 state could be found. The isomer decays offer a natural explanation for this non‐observation and provides a striking example of the influence of the near degeneracy of the vh9/2 and vf7/2 orbitals on the properties of nuclei in this region.

Spontaneous breaking of superconformal invariance in (2+1) D supersymmetric Chern-Simons-matter theories in the large N limit

In this work we study the spontaneous breaking of superconformal and gauge invariances in the Abelian N = 1,2 three-dimensional supersymmetric Chern-Simons-matter (SCSM) theories in a large N flavor limit. We compute the Kahlerian effective superpotential at subleading order in 1/N and show that the Coleman-Weinberg mechanism is responsible for the dynamical generation of a mass scale in the N = 1 model. This effect appears due to two-loop diagrams that are logarithmic divergent. We also show that the Coleman-Weinberg mechanism fails when we lift from the N = 1 to the N = 2 SCSM model. (C) 2010 Elsevier B.V All rights reserved.

OMG!: characterizing the role of emotions in the sharing of online commercial videos

"Se tornar viral" é visto pelos comerciantes como o novo Graal para alcançar grandes comunidades online. Neste contexto viral, vídeos têm um papel especial dada a forte capacidade deles de se espalhar exponencialmente pela internet através do compartilhamento social. Cada ano se vê a quebra de novos recordes através deste tipo de viralidade. Em março de 2012, o vídeo "Kony 2012" envolvendo a ação unida contra o líder de milícia Africano epônimo, atingiu mais de 34 milhões de visualizações em seu primeiro dia de lançamento. Em dezembro de 2012, o vídeo-clipe da música "Gangnam Style" tornou-se o primeiro vídeo do YouTube a alcançar mais de um bilhão de visualizações, totalizando mais de 1,4 bilhões de visualizações em março de 2013. Tais ilustrações mostram claramente a nova escala que a internet deu ao fenômeno do boca-a-boca. Os comerciantes entenderam o potencial fantástico dos vídeos virais e tentaram aproveitar o fenômeno de modo a reproduzi-lo para fins comerciais. Esta pesquisa oferece para os acadêmicos e os profissionais de marketing uma análise dos determinantes do compartilhamento de vídeos comerciais online. Mais especificamente, o foco da dissertação foi definido sobre o papel das emoções no compartilhamento, para identificar quais delas levam e como levam à partilha de vídeos comerciais online. A pesquisa foi realizada a partir de dois métodos científicos: uma pesquisa e uma análise de texto sobre a atribuição de emoções para comentários dos vídeos mais compartilhados do YouTube. A pesquisa confirma, com novos métodos, hipóteses previamente testadas e validadas por acadêmicos. Ela mostra que a positividade e a força das emoções são determinantes de compartilhamento maiores do que a negatividade e a fraqueza (Lindgreen and Vanhamme, 2005; Dobele et al., 2007). A dissertação também argumenta que o conteúdo do vídeo, bem como o contexto são determinantes significativos de compartilhamento de vídeo (Laskey et al., 1989; Taylor, 1999). Além de validar teorias existentes, a pesquisa trouxe novos conceitos para a discussão, especialmente o papel da dimensão força / fraqueza de emoções para analisar o fenômeno viral, e a importância de uma clara "chamada à ação" incluída no vídeo para aumentar a sua partilha. Estes novos conceitos enriquecem a literatura do tema – que evolui muito rapidamente – e preparam o caminho para futuras pesquisas.

Jahn-Teller effect on the structure of the Sm-doped PbTiO3: A theoretical approach

Samarium doped PbTiO3 (PT:Sm) and pure PbTiO3 (PT) powders were obtained by polymeric precursor method. These powders were characterized by X-ray diffraction (XRD) and theoretical calculations using the CRYSTAL98 program. The effect of the samarium atom is taken into account only indirectly. The experimental models were compared with the cubic (ideal) and tetragonal theoretical models. The structure deformations existent in the experimental compounds were analyzed from the tiny structural differences that lead to perturbations in the crystal orbital splittings. This paper proposes an efficient alternative methodology for defining structural distortions. (c) 2007 Elsevier B.V. All rights reserved.

Changes of social relevance in the transplantation of theories: the examples of economics and agronomics

Includes bibliography

Observation of the rare B-s(0)->mu(+)mu(-) decay from the combined analysis of CMS and LHCb data

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Radiative Omega(-)->Xi(-)gamma decay and physics beyond the standard model

We investigate the impact of new physics beyond the standard model to the s → dγ process, which is responsible for the short-distance contribution to the radiative decay Ω-Ξ-γ. We study three representative extensions of the standard model: namely, a one-family technicolor model, a two-Higgs-doublet model, and a model containing scalar leptoquarks. When constraints arising from the observed b→sγ transition and the upper limit on D0-D̄0 mixing are taken into account, we find no significant contributions of new physics to the s→dy process.

Beyond the diffraction limit of optical/IR interferometers I. Angular diameter and rotation parameters of Achernar from differential phases

Context. Spectrally resolved long-baseline optical/IR interferometry of rotating stars opens perspectives to investigate their fundamental parameters and the physical mechanisms that govern their interior, photosphere, and circumstellar envelope structures. Aims. Based on the signatures of stellar rotation on observed interferometric wavelength-differential phases, we aim to measure angular diameters, rotation velocities, and orientation of stellar rotation axes. Methods. We used the AMBER focal instrument at ESO-VLTI in its high-spectral resolution mode to record interferometric data on the fast rotator Achernar. Differential phases centered on the hydrogen Br gamma line (K band) were obtained during four almost consecutive nights with a continuous Earth-rotation synthesis during similar to 5h/night, corresponding to similar to 60 degrees position angle coverage per baseline. These observations were interpreted with our numerical code dedicated to long-baseline interferometry of rotating stars. Results. By fitting our model to Achernar's differential phases from AMBER, we could measure its equatorial radius R-eq = 11.6 +/- 0.3 R-circle dot, equatorial rotation velocity V-eq = 298 +/- 9 km s(-1), rotation axis inclination angle i = 101.5 +/- 5.2 degrees, and rotation axis position angle (from North to East) PA(rot) = 34.9 +/- 1.6 degrees. From these parameters and the stellar distance, the equatorial angular diameter circle divide(eq) of Achernar is found to be 2.45 +/- 0.09 mas, which is compatible with previous values derived from the commonly used visibility amplitude. In particular, circle divide(eq) and PA(rot) measured in this work with VLTI/AMBER are compatible with the values previously obtained with VLTI/VINCI. Conclusions. The present paper, based on real data, demonstrates the super-resolution potential of differential interferometry for measuring sizes, rotation velocities, and orientation of rotating stars in cases where visibility amplitudes are unavailable and/or when the star is partially or poorly resolved. In particular, we showed that differential phases allow the measurement of sizes up to similar to 4 times smaller than the diffraction-limited angular resolution of the interferometer.

Study of the X(3872) state with the CMS experiment at LHC

The surprising discovery of the X(3872) resonance by the Belle experiment in 2003, and subsequent confirmation by BaBar, CDF and D0, opened up a new chapter of QCD studies and puzzles. Since then, detailed experimental and theoretical studies have been performed in attempt to determine and explain the proprieties of this state. Since the end of 2009 the world’s largest and highest-energy particle accelerator, the Large Hadron Collider (LHC), started its operations at the CERN laboratories in Geneva. One of the main experiments at LHC is CMS (Compact Muon Solenoid), a general purpose detector projected to address a wide range of physical phenomena, in particular the search of the Higgs boson, the only still unconfirmed element of the Standard Model (SM) of particle interactions and, new physics beyond the SM itself. Even if CMS has been designed to study high energy events, it’s high resolution central tracker and superior muon spectrometer made it an optimal tool to study the X(3872) state. In this thesis are presented the results of a series of study on the X(3872) state performed with the CMS experiment. Already with the first year worth of data, a clear peak for the X(3872) has been identified, and the measurement of the cross section ratio with respect to the Psi(2S) has been performed. With the increased statistic collected during 2011 it has been possible to study, in bins of transverse momentum, the cross section ratio between X(3872) and Psi(2S) and separate their prompt and non-prompt component.