2,934 research outputs found
Anatomia endobrônquica: estudo prospectivo das variações anatómicas da árvore traqueobrônquica
ResumoO conhecimento detalhado do normal padrão de ramificações da árvore traqueobrônquica é um requisito essencial para qualquer pneumologista. Os sistemas de classificação funcional que guiam a prática clínica corrente têm um carácter eminentemente estático e raramente contemplam referências aos desvios possíveis dentro do espectro normal.Por forma a caracterizar as variações anatómicas da árvore traqueobrônquica, os autores desenvolveram um estudo prospectivo que decorreu entre Fevereiro e Julho de 2009, onde se incluíram todos os doentes referenciados para realização de broncofibroscopias diagnósticas e/ou terapêuticas.Um total de 181 indivíduos foram incluídos no estudo tendo-se observado variantes anatómicas em 79 (43% do total). Globalmente observamos 20 diferentes variantes anatómicas. Estas variantes foram mais frequentemente observadas no lobo superior direito (16,6%). O lobo médio e a língula não foram sede de variantes anatómicas. A variante mais frequentemente observada foi o padrão bifurcado do lobo superior direito (13,8%).O presente estudo revelou uma elevada frequência de formas alternativas ao clássico padrão de ramificação traqueobrônquica. O conhecimento da tipologia, morfologia e frequência de expressão dessas variantes revela-se de extrema importância para o broncologista no estabelecimento das fronteiras da anatomia normal e na planificação de técnicas endoscópicas ou de procedimentos cirúrgicos.AbstractA comprehensive knowledge of the normal pattern of endobronchial branching is essential to any pulmonologist. The classification systems available are predominantly static descriptions and only seldom do they refer to possible variations within the normal spectrum.To evaluate all possible anatomical variants of the tracheobronchial tree we conducted a prospective study in our endoscopy unit between February, 1st and July, 10th (2009).A total of 181 individuals were included in the study. Anatomical variants were found to be present in 79 individuals (43% of total). Overall we found 20 different anatomical variants. Variations were more frequently found within the right upper lobe (16.6% of individuals). Middle lobe and lingula presented no variations. The variant most frequently found was the presence of a bifurcate pattern of the right upper bronchus (13.8%).The present study revealed a relatively high frequency of anatomical alternatives to the normal endobronchial branching pattern. Recognition of these variants and the frequency of their expression are fundamental for the bronchologist in establishing the limits of normal anatomy and preparing endobronchial techniques or surgical procedures
Transfer/Breakup Modes in the 6He+209Bi Reaction Near and Below the Coulomb Barrier
Reaction products from the interaction of 6He with 209Bi have been measured
at energies near the Coulomb barrier. A 4He group of remarkable intensity,
which dominates the total reaction cross section, has been observed. The
angular distribution of the group suggests that it results primarily from a
direct nuclear process. It is likely that this transfer/breakup channel is the
doorway state that accounts for the previously observed large sub-barrier
fusion enhancement in this system.Comment: 4 pages; 3 figure
Desenvolvimento de uma ferramenta para identificar regiões codificadoras nos transcritos do fungo Phakopsora pachyrhizi.
WB2016
BCS and generalized BCS superconductivity in relativistic quantum field theory. I. formulation
We investigate the BCS and generalized BCS theories in the relativistic
quantum field theory. We select the gauge freedom as U(1), and introduce a
BCS-type effective attractive interaction. After introducing the Gor'kov
formalism and performing the group theoretical consideration of the mean
fields, we solve the relativistic Gor'kov equation and obtain the Green's
functions in analytical forms. We obtain various types of gap equations.Comment: 31 page
Spin dependent quantum interference in non-local graphene spin valves
Spin dependent electron transport measurements on graphene are of high
importance to explore possible spintronic applications. Up to date all spin
transport experiments on graphene were done in a semi-classical regime,
disregarding quantum transport properties such as phase coherence and
interference. Here we show that in a quantum coherent graphene nanostructure
the non-local voltage is strongly modulated. Using non-local measurements, we
separate the signal in spin dependent and spin independent contributions. We
show that the spin dependent contribution is about two orders of magnitude
larger than the spin independent one, when corrected for the finite
polarization of the electrodes. The non-local spin signal is not only strongly
modulated but also changes polarity as a function of the applied gate voltage.
By locally tuning the carrier density in the constriction we show that the
constriction plays a major role in this effect and indicates that it can act as
a spin filter device. Our results show the potential of quantum coherent
graphene nanostructures for the use in future spintronic devices
Proton drip-line nuclei in Relativistic Hartree-Bogoliubov theory
Ground-state properties of spherical even-even nuclei and
are described in the framework of Relativistic Hartree Bogoliubov
(RHB) theory. The model uses the NL3 effective interaction in the mean-field
Lagrangian, and describes pairing correlations by the pairing part of the
finite range Gogny interaction D1S. Binding energies, two-proton separation
energies, and proton radii that result from fully self-consistent RHB
solutions are compared with experimental data. The model predicts the location
of the proton drip-line. The isospin dependence of the effective spin-orbit
potential is discussed, as well as pairing properties that result from the
finite range interaction in the channel.Comment: 12 pages, RevTex, 10 p.s figures, submitted to Phys. Rev.
Crescimento de soja geneticamente modificada com os genes AtDREB1A e AtDREB2A sob déficit hídrico.
Nanosecond spin lifetimes in single- and few-layer graphene-hBN heterostructures at room temperature
We present a new fabrication method of graphene spin-valve devices which
yields enhanced spin and charge transport properties by improving both the
electrode-to-graphene and graphene-to-substrate interface. First, we prepare
Co/MgO spin injection electrodes onto Si/SiO. Thereafter, we
mechanically transfer a graphene-hBN heterostructure onto the prepatterned
electrodes. We show that room temperature spin transport in single-, bi- and
trilayer graphene devices exhibit nanosecond spin lifetimes with spin diffusion
lengths reaching 10m combined with carrier mobilities exceeding 20,000
cm/Vs.Comment: 15 pages, 5 figure
A surface kinematics buoy (SKIB) for wave–current interaction studies
Global navigation satellite systems (GNSSs) and modern motion-sensor packages
allow the measurement of ocean surface waves with low-cost drifters. Drifting
along or across current gradients provides unique measurements of
wave–current interactions. In this study, we investigate the response of
several combinations of GNSS receiver, motion-sensor package and hull design
in order to define a prototype “surface kinematics buoy” (SKIB) that is
particularly optimized for measuring wave–current interactions, including
relatively short wave components that are important for air–sea interactions
and remote-sensing applications. The comparison with existing Datawell
Directional Waverider and Surface Wave Instrument Float with Tracking (SWIFT)
buoys, as well as stereo-video imagery, demonstrates the performance of SKIB.
The use of low-cost accelerometers and a spherical ribbed and skirted hull
design provides acceptable heave spectra E(f) from 0.09 to 1 Hz with an
acceleration noise level (2πf)4E(f) close to 0.023 m2 s−3.
Velocity estimates from GNSS receivers yield a mean direction and directional
spread. Using a low-power acquisition board allows autonomous deployments
over several months with data transmitted by satellite. The capability to
measure current-induced wave variations is illustrated with data acquired in
a macro-tidal coastal environment.</p
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