3,524 research outputs found
Network of recurrent events for the Olami-Feder-Christensen model
We numerically study the dynamics of a discrete spring-block model introduced
by Olami, Feder and Christensen (OFC) to mimic earthquakes and investigate to
which extent this simple model is able to reproduce the observed spatiotemporal
clustering of seismicty. Following a recently proposed method to characterize
such clustering by networks of recurrent events [Geophys. Res. Lett. {\bf 33},
L1304, 2006], we find that for synthetic catalogs generated by the OFC model
these networks have many non-trivial statistical properties. This includes
characteristic degree distributions -- very similar to what has been observed
for real seismicity. There are, however, also significant differences between
the OFC model and earthquake catalogs indicating that this simple model is
insufficient to account for certain aspects of the spatiotemporal clustering of
seismicity.Comment: 11 pages, 16 figure
Classical and quantum coupled oscillators: symplectic structure
We consider a set of N linearly coupled harmonic oscillators and show that
the diagonalization of this problem can be put in geometrical terms. The matrix
techniques developed here allowed for solutions in both the classical and
quantum regimes.Comment: 27 pages, 6 figure
The role of c-Met and VEGFR2 in glioblastoma resistance to bevacizumab
Dismal prognosis of glioblastoma (GBM) prompts for the identification of response predictors and therapeutic resistance mechanisms of current therapies. The authors investigated the impact of c-Met, HGF, VEGFR2 expression and microvessel density (MVD) in GBM patients submitted to second-line chemotherapy with bevacizumab. Immunohistochemical expression of c-Met, HGF, VEGFR2, and MVD was assessed in tumor specimens of GBM patients treated with bevacizumab, after progression under temozolomide. Survival analysis was evaluated according to the expression of the aforementioned biomarkers. c-Met overexpression was associated with a time-to-progression (TTP) after bevacizumab of 3 months (95% CI, 1.5–4.5) compared with a TTP of 7 months (95% CI, 4.6–9.4) in patients with low or no expression of c-Met (p = 0.05). VEGFR2 expression was associated with a TTP after bevacizumab of 3 months (95% CI, 1.8–4.2) compared with a TTP of 7 months (95% CI, 5.7–8.3) in patients with no tumoral expression of VEGFR2 (p = 0.009). Concomitant c-Met/VEGFR2 overexpression was associated with worse overall survival (13 months) compared with concomitant c-Met/VEGFR2 negative expression (19 months; p = 0.025). Our data support the hypothesis that c-Met and VEGFR2 overexpression have a role in the development of glioblastoma early resistance and might predict poorer responses to anti-angiogenic therapies.This work was financed by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT-Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). Additional funding by the European Regional Development Fund (ERDF), COMPETE2020 and Portuguese national funds via FCT, under project POCI-01-0145-FEDER-016390: CANCEL STEM and the project POCI-01-0145-FEDER-031438 (PDTC/MED_ONC/31438/2017)
Cenários e ações na pesquisa federal em agricultura orgânica no Brasil
bitstream/CNPAB-2010/35702/1/doc257.pd
Monte Carlo Performance Studies for the Site Selection of the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) represents the next generation of
ground-based instruments for very-high-energy (VHE) gamma-ray astronomy, aimed
at improving on the sensitivity of current-generation experiments by an order
of magnitude and providing coverage over four decades of energy. The current
CTA design consists of two arrays of tens of imaging atmospheric Cherenkov
telescopes, comprising Small, Medium and Large-Sized Telescopes, with one array
located in each of the Northern and Southern Hemispheres. To study the effect
of the site choice on the overall \gls{cta} performance and support the site
evaluation process, detailed Monte Carlo simulations have been performed. These
results show the impact of different site-related attributes such as altitude,
night-sky background and local geomagnetic field on CTA performance for the
observation of VHE gamma rays.Comment: 34 pages, 11 figures, Accepted for publication in AP
População referência para validação de estudos genômicos e descoberta de genes em frango de corte.
Projeto: 02.10.06.003
Desempenho de cultivares de batata-doce no Distrito federal.
O presente trabalho teve como objetivo avaliar o desempenho agronômico de seis cultivares e três variedades de batata-doce nas condições edafoclimáticas no Recanto das Emas, DF
Influência do processamento do milho sobre os resíduos de Deltametrina.
Amostras de fubá, bolinho e angu, preparadas a partir de milho tratado pós-colheita cm 1 mg de deltametrina/kg foram analisadas por cromatografia gasosa com o objetivo de estudar a influência da moagem e das temperaturas utilizadas durante o preparo caseiro destes produtos, sobre os resíduos deste piretróide. os resultados mostraram que não houve alteração significativa dos resíduos de deltametrina durante estes processamentos e que a obtenção de subprodutos do milho com baixo teor deste inseticida, depende da sua aplicação correta no tratamento pós-colheita
- …