4,181 research outputs found
Ventilação não invasiva com pressão positiva intermitente - experiência de 7 anos
Introduction: Nasal intermittent positive pressure ventilation (NIPPV) is a non invasive ventilation method that combines the benefits of nasal continuous positive airway pressure (NCPAP) and the cycles of positive pressure.
Objectives: Description of the NIPPV experience in a neonatal intensive care unit.
Methods: A descriptive study of newborns ventilated with NIPPV, from January 2002 to December 2008. Were considered two groups: the first group had mechanical ventilation before NIPPV, and in the second group the initial method was non-invasive ventilation. These 2 groups were subdivided: Group 1: sub-group A, NIPPV immediately after weaning and sub- group B, NIPPV after mechanical ventilation followed by NCPAP. The group 2 was sub-divided in sub-group C, NIPPV after NCPAP, and sub-group D, NIPPV as the initial mode of ventilation.
Results: In group 1 we analysed 79 cycles of ventilation with 89% of success and in group 2 55 cycles, with 69% of success. Newborns in group 1 had a median weight of 925g and gestational age of 27 weeks and the group 2 had 1350g and 30 weeks, respectively.
Conclusions: NIPPV was used mainly after conventional ventilation in lighter and immature babies, without relevant complications
Detection and whole genome sequencing of CPMMV in common bean resistant to BGMV from Paraná State.
Cowpea mild mottle virus (CPMMV) is a Carlavirus from the family Betaflexiviridae which has a linear single stranded positive sense rna genome of approximately 8,200 nt and infects a wide range of cultivated plants from the Fabaceae family. It is transmitted by the whitefly Bemisia tabaci
Hybridization patterns between two marine snails, Littorina fabalis and L. obtusata
Characterizing the patterns of hybridization between closely related species is crucial to understand the role of gene flow in speciation. In particular, systems comprising multiple contacts between sister species offer an outstanding opportunity to investigate how reproductive isolation varies with environmental conditions, demography and geographic contexts of divergence. The flat periwinkles, Littorina obtusata and L. fabalis (Gastropoda), are two intertidal sister species with marked ecological differences compatible with late stages of speciation. Although hybridization between the two was previously suggested, its extent across the Atlantic shores of Europe remained largely unknown. Here, we combined genetic (microsatellites and mtDNA) and morphological data (shell and male genital morphology) from multiple populations of flat periwinkles in north‐western Iberia to assess the extent of current and past hybridization between L. obtusata and L. fabalis under two contrasting geographic settings of divergence (sympatry and allopatry). Hybridization signatures based on both mtDNA and microsatellites were stronger in sympatric sites, although evidence for recent extensive admixture was found in a single location. Misidentification of individuals into species based on shell morphology was higher in sympatric than in allopatric sites. However, despite hybridization, species distinctiveness based on this phenotypic trait together with male genital morphology remained relatively high. The observed variation in the extent of hybridization among locations provides a rare opportunity for future studies on the consequences of different levels of gene flow for reinforcement, thus informing about the mechanisms underlying the completion of speciation
Evidence for a spectroscopic direct detection of reflected light from 51 Peg b
The detection of reflected light from an exoplanet is a difficult technical
challenge at optical wavelengths. Even though this signal is expected to
replicate the stellar signal, not only is it several orders of magnitude
fainter, but it is also hidden among the stellar noise. We apply a variant of
the cross-correlation technique to HARPS observations of 51 Peg to detect the
reflected signal from planet 51 Peg b. Our method makes use of the
cross-correlation function of a binary mask with high-resolution spectra to
amplify the minute planetary signal that is present in the spectra by a factor
proportional to the number of spectral lines when performing the cross
correlation. The resulting cross-correlation functions are then normalized by a
stellar template to remove the stellar signal. Carefully selected sections of
the resulting normalized CCFs are stacked to increase the planetary signal
further. The recovered signal allows probing several of the planetary
properties, including its real mass and albedo. We detect evidence for the
reflected signal from planet 51 Peg b at a significance of 3\sigma_noise. The
detection of the signal permits us to infer a real mass of 0.46^+0.06_-0.01
M_Jup (assuming a stellar mass of 1.04\;M_Sun) for the planet and an orbital
inclination of 80^+10_-19 degrees. The analysis of the data also allows us to
infer a tentative value for the (radius-dependent) geometric albedo of the
planet. The results suggest that 51Peg b may be an inflated hot Jupiter with a
high albedo (e.g., an albedo of 0.5 yields a radius of 1.9 \pm 0.3 R_Jup for a
signal amplitude of 6.0\pm0.4 x 10^-5). We confirm that the method we perfected
can be used to retrieve an exoplanet's reflected signal, even with current
observing facilities. The advent of next generation of observing facilities
will yield new opportunities for this type of technique to probe deeper into
exoplanets.Comment: 9 pages, 6 figure
Experimental polarization encoded quantum key distribution over optical fibres with real-time continuous birefringence compensation
In this paper we demonstrate an active polarization drift compensation scheme
for optical fibres employed in a quantum key distribution experiment with
polarization encoded qubits. The quantum signals are wavelength multiplexed in
one fibre along with two classical optical side channels that provide the
control information for the polarization compensation scheme. This set-up
allows us to continuously track any polarization change without the need to
interrupt the key exchange. The results obtained show that fast polarization
rotations of the order of 40*pi rad/s are effectively compensated for. We
demonstrate that our set-up allows continuous quantum key distribution even in
a fibre stressed by random polarization fluctuations. Our results pave the way
for Bell-state measurements using only linear optics with parties separated by
long-distance optical fibres
Resonant enhancements of high-order harmonic generation
Solving the one-dimensional time-dependent Schr\"odinger equation for simple
model potentials, we investigate resonance-enhanced high-order harmonic
generation, with emphasis on the physical mechanism of the enhancement. By
truncating a long-range potential, we investigate the significance of the
long-range tail, the Rydberg series, and the existence of highly excited states
for the enhancements in question. We conclude that the channel closings typical
of a short-range or zero-range potential are capable of generating essentially
the same effects.Comment: 7 pages revtex, 4 figures (ps files
Procedimentos para coleta e envio de amostras de leite para determinação da composição e das contagens de células somáticas e de bactérias.
bitstream/item/65285/1/CT-92-Procedimentos-para-coleta-e-envio.pd
Analysing bifurcations encountered in numerical modelling of current transfer to cathodes of dc glow and arc discharges
Bifurcations and/or their consequences are frequently encountered in numerical modelling of
current transfer to cathodes of gas discharges, also in apparently simple situations, and a
failure to recognize and properly analyse a bifurcation may create difficulties in the modelling
and hinder the understanding of numerical results and the underlying physics. This work is
concerned with analysis of bifurcations that have been encountered in the modelling of
steady-state current transfer to cathodes of glow and arc discharges. All basic types of
steady-state bifurcations (fold, transcritical, pitchfork) have been identified and analysed. The
analysis provides explanations to many results obtained in numerical modelling. In particular,
it is shown that dramatic changes in patterns of current transfer to cathodes of both glow and
arc discharges, described by numerical modelling, occur through perturbed transcritical
bifurcations of first- and second-order contact. The analysis elucidates the reason why the
mode of glow discharge associated with the falling section of the current–voltage
characteristic in the solution of von Engel and Steenbeck seems not to appear in 2D numerical
modelling and the subnormal and normal modes appear instead. A similar effect has been
identified in numerical modelling of arc cathodes and explained.info:eu-repo/semantics/publishedVersio
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