135 research outputs found
Rupture characteristics of major and great (M_w ≥ 7.0) megathrust earthquakes from 1990 to 2015: 1. Source parameter scaling relationships
Source parameter scaling for major and great thrust-faulting events on circum-Pacific megathrusts is examined using uniformly processed finite-fault inversions and radiated energy estimates for 114 M_w ≥ 7.0 earthquakes. To address the limited resolution of source spatial extent and rupture expansion velocity (V_r) from teleseismic observations, the events are subdivided into either group 1 (18 events) having independent constraints on V_r from prior studies or group 2 (96 events) lacking independent V_r constraints. For group 2, finite-fault inversions with V_r = 2.0, 2.5, and 3.0 km/s are performed. The product V_r^3Δσ_E, with stress drop Δσ_E calculated for the slip distribution in the inverted finite-fault models, is very stable for each event across the suite of models considered. It has little trend with M_w, although there is a baseline shift to low values for large tsunami earthquakes. Source centroid time (T_c) and duration (T_d), measured from the finite-fault moment rate functions vary systematically with the cube root of seismic moment (M_0), independent of assumed V_r. There is no strong dependence on magnitude or Vr for moment-scaled radiated energy (E_R/M_0) or apparent stress (σ_a). Δσ_E averages ~4 MPa, with direct trade-off between V_r and estimated stress drop but little dependence on M_w. Similar behavior is found for radiation efficiency (η_R). We use V_r^3Δσ_E and T_c/M_0^(1/3) to explore variation of stress drop, V_r and radiation efficiency, along with finite-source geometrical factors. Radiation efficiency tends to decrease with average slip for these very large events, and fracture energy increases steadily with slip
Rupture characteristics of major and great (M_w ≥ 7.0) megathrust earthquakes from 1990 to 2015: 2. Depth dependence
Depth-varying characteristics of high-frequency seismic radiation for megathrust earthquakes have been inferred from several recent giant earthquakes and large tsunami earthquakes. To quantify any depth dependence more extensively, we analyzed 114 M_w ≥ 7.0 thrust-faulting earthquakes with centroid depths from 5 to 55 km on circum-Pacific megathrusts using teleseismic body wave finite-fault inversions and source spectrum determinations. Large tsunami earthquakes and some other shallow events at depths less than about 18 km have unusually long source durations, and low values of static stress drop (Δσ_E), V_r^3Δσ_E, and apparent stress, with relatively depleted high-frequency radiation. Deeper events have no clear global trend with source depth for moment-normalized centroid time or total duration, static stress drop, moment-scaled radiated energy, apparent stress, or radiation efficiency. Regional behavior among the 17 sampled subduction zones generally conforms to the global composite. The source spectra have high-frequency logarithmic spectral decay slopes averaging ~ −1.6. There is relative enrichment in high-frequency spectral levels with increasing source depth manifested in reduced high-frequency spectral decay slope. The ratio of high-frequency (0.3–1 Hz) radiated energy to total energy increases correspondingly. These observations suggest that overall dynamic rupture processes are relatively insensitive to source depth, but varying scale lengths of megathrust heterogeneity may contribute to modest enrichment of high-frequency seismic radiation for events deeper on the megathrust. A weak correlation of higher estimated average megathrust temperature at 30 km depth with higher spectral decay rate indicates that the depth-varying pattern may in part result from frictional properties being influenced by temperature variations or by systematic reduction of average attenuation with increasing depth along the megathrust
FATORES EXPLICATIVOS DA EVIDENCIAÇÃO DOS BENEFÍCIOS AOS EMPREGADOS EM EMPRESAS BRASILEIRAS LISTADAS NO IBRX 100 DA BM&FBOVESPA
A informação contábil desempenha papel importante na redução da assimetria de informação entre os diversos atores do mercado. Uma das novas exigências advindas do processo de convergência às normas contábeis internacionais é a divulgação dos benefícios a empregados, que pode constituir em informação relevante sobre o passivo da organização, principalmente para as entidades que mantém planos de benefícios a seus empregados. Este estudo teve o objetivo de identificar os fatores que explicam o nível de evidenciação do CPC 33 (benefícios aos empregados) das empresas brasileiras listadas no IBRx 100 da BM&FBovespa. Neste sentido, a amostra do estudo foi formada por 76 empresas. Como prováveis fatores explicativos extraídos da literatura, foram testados o tamanho, retorno sobre o ativo, endividamento, rentabilidade, existência do comitê de auditoria e de membros externos no conselho de administração. Para tratamento dos dados utilizou-se da regressão linear múltipla. Os resultados apontam que o tamanho, a rentabilidade e a existência de membros externos no conselho de administração ajudam a explicar o nível de evidenciação dos benefícios a empregados. Conclui-se que ainda há um longo caminho a ser percorrido pelas empresas no que se refere a divulgação dos benefícios aos empregados, uma vez que o índice de divulgação encontrado no presente estudo foi relativamente baixo
Clinical Application of Mesenchymal Stem Cells and Novel Supportive Therapies for Oral Bone Regeneration
This work has been also recommended by the PACT (Platelet and Advanced Cell Therapies) Forum Civitatis of the POSEIDO Academic Consortium (Periodontology, Oral Surgery, Esthetic and Implant Dentistry Organization).Bone regeneration is often needed prior to dental implant treatment due to the lack of adequate quantity and quality of the bone after infectious diseases, trauma, tumor, or congenital conditions. In these situations, cell transplantation technologies may help to overcome the limitations of autografts, xenografts, allografts, and alloplastic materials. A database search was conducted to include human clinical trials (randomized or controlled) and case reports/series describing the clinical use of mesenchymal stem cells (MSCs) in the oral cavity for bone regeneration only specifically excluding periodontal regeneration. Additionally, novel advances in related technologies are also described. 190 records were identified. 51 articles were selected for full-text assessment, and only 28 met the inclusion criteria: 9 case series, 10 case reports, and 9 randomized controlled clinical trials. Collectively, they evaluate the use of MSCs in a total of 290 patients in 342 interventions. The current published literature is very diverse in methodology and measurement of outcomes. Moreover, the clinical significance is limited. Therefore, the use of these techniques should be further studied in more challenging clinical scenarios with well-designed and standardized RCTs, potentially in combination with new scaffolding techniques and bioactive molecules to improve the final outcomes.The authors of this paper were partially supported by the Talentia Scholarship Program (Junta de Andalucía, Spain) (MPM), the International Team for Implantology through the ITI Scholarship Program (AL), and the Research Groups #CTS-138 and #CTS-583 (Junta de Andalucía, Spain) (All)
The 2009 Samoa–Tonga great earthquake triggered doublet
Great earthquakes (having seismic magnitudes of at least 8) usually involve abrupt sliding of rock masses at a boundary between tectonic plates. Such interplate ruptures produce dynamic and static stress changes that can activate nearby intraplate aftershocks, as is commonly observed in the trench-slope region seaward of a great subduction zone thrust event1. The earthquake sequence addressed here involves a rare instance in which a great trench-slope intraplate earthquake triggered extensive interplate faulting, reversing the typical pattern and broadly expanding the seismic and tsunami hazard. On 29 September 2009, within two minutes of the initiation of a normal faulting event with moment magnitude 8.1 in the outer trench-slope at the northern end of the Tonga subduction zone, two major interplate underthrusting subevents (both with moment magnitude 7.8), with total moment equal to a second great earthquake of moment magnitude 8.0, ruptured the nearby subduction zone megathrust. The collective faulting produced tsunami waves with localized regions of about 12 metres run-up that claimed 192 lives in Samoa, American Samoa and Tonga. Overlap of the seismic signals obscured the fact that distinct faults separated by more than 50 km had ruptured with different geometries, with the triggered thrust faulting only being revealed by detailed seismic wave analyses. Extensive interplate and intraplate aftershock activity was activated over a large region of the northern Tonga subduction zone
THEORETICAL BASIS, HYPOTHESIS AND CONSTRUCT IN ACCOUNTING STUDIES
The present study aims at contributing to the understanding of distinct concepts about theoretical basis, hypothesis and construct by presenting, discussing, explaining and exemplifying the meanings of such concepts, their conceptual definitions, operational definitions and constructs in studies carried out in the Accounting area. Theory plays a relevant role in developing scientific knowledge since it represents the highest level of science epistemology. Hypotheses are a powerful tool for advancing knowledge since they can be tested. However, to be able to empirically explore a theoretical concept, one needs to translate the concept statement into a relation with the real world, based on variables, and on observable and measurable phenomena, in other words, one needs to elaborate a construct and operationalize it. Therefore, it is possible that the ones who are interested in the findings of a specific study share the same understandings about the concepts, definitions, possible constructs and variables included in the study, thus, comprehending findings, conclusions and limitations of the study in a similar manner. The present study contributes to the area by highlighting the intention of correct understanding and usage of these essential categories of the scientific and professional discourse, according to the theoretical background.
RESPONSABILIDADE SOCIOAMBIENTAL E OS REFLEXOS FINANCEIROS NAS EMPRESAS DO SETOR DE ENERGIA
O objetivo do estudo foi analisar a influência dos investimentos sociais e ambientais no desempenho econômico das 20 maiores empresas do setor energético listadas na Revista Exame 2012. Os dados foram coletados através dos balanços sociais das empresas no modelo proposto pelo Instituto Brasileiro de Análises Sociais e Econômicas – IBASE, entre o período de 2008 e 2011. A metodologia da pesquisa tem caráter descritivo quanto aos fins abordados, em seu desenvolvimento caracteriza-se como bibliográfica e documental e, por fim, sua natureza tem cunho quantitativo. Na análise da correlação entre os indicadores socioambientais e financeiros, foi utilizado o coeficiente de correlação linear simples de Pearson. Os resultados indicam que existe uma correlação forte positiva entre os indicadores sociais externos e ambientais e os indicadores financeiros tais como a receita liquida, a receita operacional e o lucro líquido. As evidências convergem com as pesquisas anteriores sobre o tema. Por outro lado, em relação aos indicadores sociais internos, não foi encontrado correlação com os indicadores financeiros. O resultado apontado revela que as organizações estão preocupadas em melhorar sua imagem através do atendimento dos anseios sociais mais exigidos na atualidade, questões ambientais e desenvolvimento social
Simultaneous analysis of the elastic scattering and breakup channel for the reaction 11 Li + 208 Pb at energies near the Coulomb barrier
We present a detailed analysis of the elastic scattering and breakup channel for the reaction of Li11 on Pb208 at incident laboratory energies of 24.3 and 29.8 MeV, measured at the radioactive ion beam facility of TRIUMF, in Vancouver, Canada. A large yield of Li9 fragments was detected by four charged particle telescopes in a wide angular range. The experimental angular and energy distributions of these Li9 fragments have been compared to coupled-reaction-channel and continuum-discretized coupled-channel calculations. The large production of Li9 fragments at small angles can be explained by considering a direct breakup mechanism, while at medium-large angles a competition between direct breakup and neutron transfer to the continuum of the Pb208 target was observed.Proyecto Nacional (España) PA2009-08848 PA2009-07387 PA2010-22131-C02-01 FPA2009-07653 FPA2012-32443Programa Consolider-Ingenio 2010 (España) CSD2007-0004
Scattering of the Halo Nucleus 11Be on 197Au at Energies around the Coulomb Barrier
Angular distributions of the elastic, inelastic, and breakup cross sections of the halo nucleus 11Be on197 Au were measured at energies below (Elab =31.9 MeV) and around (39.6 MeV) the Coulomb barrier. These three channels were unambiguously separated for the first time for reactions of 11Be on a high-Z target at low energies. The experiment was performed at TRIUMF (Vancouver, Canada). The differential cross sections were compared with three different calculations: semiclassical, inert-core continuum-coupled-channels and continuum-coupled-channels ones with including core deformation. These results show conclusively that the elastic and inelastic differential cross sections can only be accounted for if core-excited admixtures are taken into account. The cross sections for these channels strongly depend on the β (E1) distribution in 11Be, and the reaction mechanism is sensitive to the entanglement of core and halo degrees of freedom in 11Be.Ministerio de Economía y Competitividad FPA2015-64969-P, FIS2014-53448-C2-1-P, FPA2013-47327-c02-01-R, FPA2012-32443, FIS2013-41994-PCentro Nacional de Física de Partículas, Astropartículas y Nuclear CSD2007- 00042European Collaborative Research EUI-2009-04162European Unions 654002Nuclear Astrophysics Virtual Institute VH-VI-417European Commission, Seventh Framework Program 60037
Reaction of the halo nucleus be on heavy targets at energies around the coulomb barrier
Presented at the XXXIII Mazurian Lakes Conference on Physics, Piaski, Poland, September 1–7, 2013.-- et al.New data for the reaction 11Be on 197Au at E lab = 31:9 MeV are presented. The angular distributions of the inelastically scattered 11Be and the 10Be fragments coming from the 11Be dissociation have been extracted and compared with semiclassical and coupled-channels calculations in an angular range θlab = 13deg;-46deg; for the detected Be fragment.This work was supported by the Spanish Government under the projects FPA2009-07387, FPA2009-07653, FPA2009-08848, FPA2012-32443 and Consolider
CPAN CSD2007-00042; the Helmholtz Association (HGT) through the Nuclear Astrophysics Virtual Institute (VH-VI-417); ATI Sistemas;
a Natural Sciences and Engineering Research Council of Canada grant. TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada.Peer Reviewe
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