4,319 research outputs found
A pressão coronária (às vezes) mente. . .
Comment on:
Comparative analysis of fractional flow reserve and instantaneous wave-free ratio: Results of a five-year registry. [Rev Port Cardiol. 2018]info:eu-repo/semantics/publishedVersio
Spider diversity (Arachnida: Araneae) in Atlantic Forest areas at Pedra Branca State Park, Rio de Janeiro, Brazil
BACKGROUND: There has never been any published work about the diversity of spiders in the city of Rio de Janeiro using analytical tools to measure diversity. The only available records for spider communities in nearby areas indicate 308 species in the National Park of Tijuca and 159 species in Marapendi Municipal Park. These numbers are based on a rapid survey and on an one-year survey respectively. NEW INFORMATION: This study provides a more thorough understanding of how the spider species are distributed at Pedra Branca State Park. We report a total of 14,626 spider specimens recorded from this park, representing 49 families and 373 species or morphospecies, including at least 73 undescribed species. Also, the distribution range of 45 species was expanded, and species accumulation curves estimate that there is a minimum of 388 (Bootstrap) and a maximum of 468 species (Jackknife2) for the sampled areas. These estimates indicates that the spider diversity may be higher than observed.Fil: Castanheira, Pedro. Universidade Federal do Rio de Janeiro; BrasilFil: Pérez González, Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Baptista, Renner L. C.. Universidade Federal do Rio de Janeiro; Brasi
Sensitive Dependence on Parameters of Continuous-time Nonlinear Dynamical Systems
We would like to thank the partial support of this work by the Brazilian agencies FAPESP (processes: 2011/19296-1 and 2013/26598-0, CNPq and CAPES. MSB acknowledges EPSRC Ref. EP/I032606/1.Peer reviewedPostprin
Eclipse studies of the dwarf-nova Ex Draconis
We report on high speed photometry of EX Dra in quiescence and in outburst.
The analysis of the lightcurves indicates that the outbursts do not start in
the outer disc regions. The disc expands during rise to maximum and shrinks
during decline and along the quiescent period. At the end of two outbursts the
system was seen to go through a phase of lower brightness, characterized by an
out-of-eclipse level ~15 per cent lower than the typical quiescent level and by
the fairly symmetric eclipse of a compact source at disc centre with little
evidence of a bright spot at disc rim. New eclipse timings were measured and a
revised ephemeris was derived. The residuals with respect to the linear
ephemeris are well described by a sinusoid of amplitude 1.2 minutes and period
\~4 years and are possibly related to a solar-like magnetic activity cycle in
the secondary star. Eclipse phases of the compact central source and of the
bright spot were used to derive the geometry of the binary. By constraining the
gas stream trajectory to pass through the observed position of the bright spot
we find q=0.72+/-0.06 and i= 85 +3/-2 degrees. The binary parameters were
estimated by combining the measured mass ratio with the assumption that the
secondary star obeys an empirical main sequence mass-radius relation. We find
M_1= 0.75+/-0.15 M_sun and M_2= 0.54+/-0.10 M_sun. The white dwarf at disc
centre is surrounded by an extended and variable atmosphere or boundary layer
of at least 3 times its radius and a temperature of T ~28000 K. The fluxes at
mid-eclipse yield an upper limit to the contribution of the secondary star and
lead to a lower limit photometric parallax distance of D= 290+/-80 pc. The
fluxes of the secondary star are well matched by those of a M0+/-2 main
sequence star.Comment: submitted to MNRAS, 12 pages, 9 figures; coded with MNRAS latex styl
Trapping Phenomenon Attenuates the Consequences of Tipping Points for Limit Cycles
We would like to thank the partial support of this work by the Brazilian agencies FAPESP (processes: 2011/19296-1, 2013/26598-0, and 2015/20407-3), CNPq and CAPES. MSB acknowledges EPSRC Ref. EP/I032606/1.Peer reviewedPublisher PD
Experimental observation of a complex periodic window
The existence of a special periodic window in the two-dimensional parameter
space of an experimental Chua's circuit is reported. One of the main reasons
that makes such a window special is that the observation of one implies that
other similar periodic windows must exist for other parameter values. However,
such a window has never been experimentally observed, since its size in
parameter space decreases exponentially with the period of the periodic
attractor. This property imposes clear limitations for its experimental
detection.Comment: 4.2 pages, 4 figure
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