1,052 research outputs found
Elastic Scattering Of Low-energy Electron By Lignin Precursors
We present cross sections for electron collisions with monolignol precursors obtained with the Schwinger Multichannel method. For Cs phenol system, Ï* resonances are found in the A" irreducible representation. So, mechanisms for dissociative electron attachment could give rise if Ï* resonances are found in the monolignols. © Published under licence by IOP Publishing Ltd.388PART 5De Cerqueira Leite, R.C., (2009) Energy, 34, p. 655. , 10.1016/j.energy.2008.11.001 0360-5442Oliveira, C., (2008) Appl. Phys. Lett., 93, p. 041503. , 10.1063/1.2967016 0003-6951BoudaĂŻffa, B., (2000) Sience, 287, p. 1658. , 10.1126/science.287.5458.1658 0036-8075Da Costa, R.F., (2004) J. Phys. B: At. Mol. Phys., 37, p. 129. , 0953-4075 L0
Self-avoiding walks and connective constants in small-world networks
Long-distance characteristics of small-world networks have been studied by
means of self-avoiding walks (SAW's). We consider networks generated by
rewiring links in one- and two-dimensional regular lattices. The number of
SAW's was obtained from numerical simulations as a function of the number
of steps on the considered networks. The so-called connective constant,
, which characterizes the long-distance
behavior of the walks, increases continuously with disorder strength (or
rewiring probability, ). For small , one has a linear relation , and being constants dependent on the underlying
lattice. Close to one finds the behavior expected for random graphs. An
analytical approach is given to account for the results derived from numerical
simulations. Both methods yield results agreeing with each other for small ,
and differ for close to 1, because of the different connectivity
distributions resulting in both cases.Comment: 7 pages, 5 figure
Mycobiota evolution during storage of paddy, brown and milled rice in different genotypes
Redenção: nova cultivar de tomate para a indĂșstria resistente a geminivĂrus e tospovĂrus
Lycopene-rich extract from red guava ( Psidium guajava L.) displays cytotoxic effect against human breast adenocarcinoma cell line MCF-7 via an apoptotic-like pathway
This study investigated a lycopene-rich extract from red guava (LEG) for its chemical composition using spectrophotometry, mass spectrometry, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and computational studies. The cytotoxic activity of LEG and the underlying mechanism was studied in human breast adenocarcinoma cells (MCF-7), murine fibroblast cells (NIH-3T3), BALB/c murine peritoneal macrophages, and sheep blood erythrocytes by evaluating the cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and flow cytometry. Spectrophotometry analysis showed that LEG contained 20% of lycopene per extract dry weight. Experimental and theoretical ATR-FTIR suggests the presence of lycopene, whereas MS/MS spectra obtained after fragmentation of the molecular ion [M]+âą of 536.4364 show fragment ions at m/z 269.2259, 375.3034, 444.3788, and 467.3658, corroborating the presence of lycopene mostly related to all-trans configuration. Treatment with LEG (1600 to 6.25ÎŒg/mL) for 24 and 72h significantly affected the viability of MCF-7 cells (mean half maximal inhibitory concentration [IC50]=29.85 and 5.964ÎŒg/mL, respectively) but not NIH-3T3 cells (IC50=1579 and 911.5ÎŒg/mL, respectively). Furthermore LEG at concentrations from 800 to 6.25ÎŒg/mL presented low cytotoxicity against BALB/c peritoneal macrophages (IC50â„800ÎŒg/mL) and no hemolytic activity. LEG (400 and 800ÎŒg/mL) caused reduction in the cell proliferation and induced cell cycle arrest, DNA fragmentation, modifications in the mitochondrial membrane potential, and morphologic changes related to granularity and size in MCF-7 cells; however, it failed to cause any significant damage to the cell membrane or display necrosis or traditional apoptosis. In conclusion, LEG was able to induce cytostatic and cytotoxic effects on breast cancer cells probably via induction of an apoptotic-like pathway.The authors acknowledge the computational time provided by CENAPAD/SP on the project proj697. Alexandra PlĂĄcido is gratefully to FCT by her grant SFRH/BD/97995/2013, financed by POPHâQRENâTipologia 4.1âFormação Avançada, subsidized by Fundo Social Europeu and MinistĂ©rio da CiĂȘncia, Tecnologia e Ensino Superior. The work at REQUIMTE/LAQV received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT) through project UID/QUI/50006/2013. Adriany das G. N. Amorim is grateful to CAPES by for the doctoral fellowship process no. 99999.004236/2014-09 in Federal University of PiauĂ (UFPI). Eder A. Barbosa is grateful to PNPD/CAPES for its post-doctoral fellowship.info:eu-repo/semantics/publishedVersio
Soil water potential during different phenological phases of coffee irrigated by center pivot
Some Observational Consequences of Brane World Cosmologies
The presence of dark energy in the Universe is inferred directly and
indirectly from a large body of observational evidence. The simplest and most
theoretically appealing possibility is the vacuum energy density (cosmological
constant). However, although in agreement with current observations, such a
possibility exacerbates the well known cosmological constant problem, requiring
a natural explanation for its small, but nonzero, value. In this paper we focus
our attention on another dark energy candidate, one arising from gravitational
\emph{leakage} into extra dimensions. We investigate observational constraints
from current measurements of angular size of high- compact radio-sources on
accelerated models based on this large scale modification of gravity. The
predicted age of the Universe in the context of these models is briefly
discussed. We argue that future observations will enable a more accurate test
of these cosmologies and, possibly, show that such models constitute a viable
possibility for the dark energy problem.Comment: 6 pages, 4 figures, to appear in Phys. Rev. D (minor revisions
Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection
Realistic astrophysical environments are turbulent due to the extremely high
Reynolds numbers. Therefore, the theories of reconnection intended for
describing astrophysical reconnection should not ignore the effects of
turbulence on magnetic reconnection. Turbulence is known to change the nature
of many physical processes dramatically and in this review we claim that
magnetic reconnection is not an exception. We stress that not only
astrophysical turbulence is ubiquitous, but also magnetic reconnection itself
induces turbulence. Thus turbulence must be accounted for in any realistic
astrophysical reconnection setup. We argue that due to the similarities of MHD
turbulence in relativistic and non-relativistic cases the theory of magnetic
reconnection developed for the non-relativistic case can be extended to the
relativistic case and we provide numerical simulations that support this
conjecture. We also provide quantitative comparisons of the theoretical
predictions and results of numerical experiments, including the situations when
turbulent reconnection is self-driven, i.e. the turbulence in the system is
generated by the reconnection process itself. We show how turbulent
reconnection entails the violation of magnetic flux freezing, the conclusion
that has really far reaching consequences for many realistically turbulent
astrophysical environments. In addition, we consider observational testing of
turbulent reconnection as well as numerous implications of the theory. The
former includes the Sun and solar wind reconnection, while the latter include
the process of reconnection diffusion induced by turbulent reconnection, the
acceleration of energetic particles, bursts of turbulent reconnection related
to black hole sources as well as gamma ray bursts. Finally, we explain why
turbulent reconnection cannot be explained by turbulent resistivity or derived
through the mean field approach.Comment: 66 pages, 24 figures, a chapter of the book "Magnetic Reconnection -
Concepts and Applications", editors W. Gonzalez, E. N. Parke
EmbarcaçÔes motorizadas: uma ameaça aos peixes-boi marinhos (Trichechus manatus) no Brasil
Complete measurement of three-body photodisintegration of 3He for photon energies between 0.35 and 1.55 GeV
The three-body photodisintegration of 3He has been measured with the CLAS
detector at Jefferson Lab, using tagged photons of energies between 0.35 GeV
and 1.55 GeV. The large acceptance of the spectrometer allowed us for the first
time to cover a wide momentum and angular range for the two outgoing protons.
Three kinematic regions dominated by either two- or three-body contributions
have been distinguished and analyzed. The measured cross sections have been
compared with results of a theoretical model, which, in certain kinematic
ranges, have been found to be in reasonable agreement with the data.Comment: 22 pages, 25 eps figures, 2 tables, submitted to PRC. Modifications:
removed 2 figures, improvements on others, a few minor modifications to the
tex
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