Flow Index: a novel, non-invasive, continuous, quantitative method to evaluate patient inspiratory effort during pressure support ventilation

Background: The evaluation of patient effort is pivotal during pressure support ventilation, but a non-invasive, continuous, quantitative method to assess patient inspiratory effort is still lacking. We hypothesized that the concavity of the inspiratory flow-time waveform could be useful to estimate patient’s inspiratory effort. The purpose of this study was to assess whether the shape of the inspiratory flow, as quantified by a numeric indicator, could be associated with inspiratory effort during pressure support ventilation. Methods: Twenty-four patients in pressure support ventilation were enrolled. A mathematical relationship describing the decay pattern of the inspiratory flow profile was developed. The parameter hypothesized to estimate effort was named Flow Index. Esophageal pressure, airway pressure, airflow, and volume waveforms were recorded at three support levels (maximum, minimum and baseline). The association between Flow Index and reference measures of patient effort (pressure time product and pressure generated by respiratory muscles) was evaluated using linear mixed effects models adjusted for tidal volume, respiratory rate and respiratory rate/tidal volume. Results: Flow Index was different at the three pressure support levels and all group comparisons were statistically significant. In all tested models, Flow Index was independently associated with patient effort (p < 0.001). Flow Index prediction of inspiratory effort agreed with esophageal pressure-based methods. Conclusions: Flow Index is associated with patient inspiratory effort during pressure support ventilation, and may provide potentially useful information for setting inspiratory support and monitoring patient-ventilator interactions

TIMASSS: The IRAS16293-2422 Millimeter And Submillimeter Spectral Survey. I. Observations, calibration and analysis of the line kinematics

While unbiased surveys observable from ground-based telescopes have previously been obtained towards several high mass protostars, very little exists on low mass protostars. To fill up this gap, we carried out a complete spectral survey of the bands at 3, 2, 1 and 0.8 mm towards the solar type protostar IRAS16293-2422. The observations covered about 200\,GHz and were obtained with the IRAM-30m and JCMT-15m telescopes. Particular attention was devoted to the inter-calibration of the obtained spectra with previous observations. All the lines detected with more than 3 sigma and free from obvious blending effects were fitted with Gaussians to estimate their basic kinematic properties. More than 4000 lines were detected (with sigma \geq 3) and identified, yielding a line density of approximatively 20 lines per GHz, comparable to previous surveys in massive hot cores. The vast majority (~2/3) of the lines are weak and due to complex organic molecules. The analysis of the profiles of more than 1000 lines belonging 70 species firmly establishes the presence of two distinct velocity components, associated with the two objects, A and B, forming the IRAS16293-2422 binary system. In the source A, the line widths of several species increase with the upper level energy of the transition, a behavior compatible with gas infalling towards a ~1 Mo object. The source B, which does not show this effect, might have a much lower central mass of ~0.1 Mo. The difference in the rest velocities of both objects is consistent with the hypothesis that the source B rotates around the source A. This spectral survey, although obtained with single-dish telescope with a low spatial resolution, allows to separate the emission from 2 different components, thanks to the large number of lines detected. The data of the survey are public and can be retrieved on the web site http://www-laog.obs.ujf-grenoble.fr/heberges/timasss.Comment: 41 pages (26 pages of online Tables), 7 Tables and 6 Figure

Communication: Observation of homonuclear propensity in collisional relaxation of the 13C12CD2 (v2 = 1) isotopologue of acetylene by stimulated Raman spectroscopy

4 p.: gráf.We report the first experimental observation of homonuclear propensity in collisional relaxation of a polyatomic molecule. A pump-probe stimulated Raman setup is used to pump population to a single rotational level of the v2 = 1 vibrationally excited state in 13C12CD2 and then monitor the redistribution of the rotational population that has taken place after a fixed delay. The Q-branch of the 2ν2–ν2 band shows a pattern of intensity alternation between the even and the odd rotational components, with the greater intensities always corresponding to the rotational levels with the same parity as the one where all the population was initially deposited. The effect can be explained by the existence of a propensity rule that favors collisional relaxation between rovibrational levels of the same parity. © 2011 American Institute of Physics.Funding received from the Spanish Ministry of Science and Innovation through research Grant No. FIS2009-08069; support from CONSOLIDER-INGENIO 2010 Program CSD2009-00038Peer reviewe

Empirical anharmonic force field and equilibrium structure of hypochlorous acid, HOCl

The cubic and quartic force fields of HOCl are investigated on the basis of the most recent experimental data on vibration-rotation interaction constants and anharmonicity constants. Some discrepancies with respect to previously reported ab initio results are found and discussed. The geometrical parameters of this molecule are also evaluated from recent data on the equilibrium values of the moments of inertia.© 1996 Published by Elsevier B.V.Cooperation Program between CNR of Italy and CSIC of Spain. Spanish DGICYT, project PB93-0138.Peer Reviewe

Urban wake-field generation using large-eddy simulation for application to quadrotor flight

A method is presented for using large-eddy simulation to generate urban wake fields for use in studying the effects on the autonomous flight performance of a small quadrotor. The flowfield is solved around a single square building using OpenFOAM and stored in a database accessed by a MATLAB/Simulink flight simulator. Four flight missions are evaluated to compare the difference in performance between wake fields generated by Reynolds-averaged Navier-Stokes and large-eddy simulation solutions. The results of the holding position in a constant freestream wind show both methods produce similar results and can hold position in all three directions within approximately ±1.5 body lengths. When the quadrotor is in or on the boundary of the building wake, the maximum deviation volumes, as calculated when using a Reynolds-averaged Navier-Stokes or large-eddy simulation air wake, can differ by two orders of magnitude. Additionally, the large-eddy simulation air wakes can cause skewed deviations by as much as five to one in a given direction for both holding position and moving along a desired flight path. Since the turbulent large-eddy simulation wake field more accurately reflects the flow physics present within the wake of real-world structures, it is recommended that large-eddy-simulation-generated wake fields be used when designing and testing autonomous control algorithms for multirotor unmanned aerial vehicles on the order of 0.5min size and 2 kg in mass

Carbon suboxide: the infrared spectrum from 1800 to 2600 cm-1

The infrared spectrum of carbon suboxide has been recorded from 1800 to 2600 cm−1 at a resolution of 0.003 cm−1. About 7% of the ca. 40 000 lines observed have been assigned and analyzed, belonging to 36 different bands. Most of these are associated with the fundamental ν3, at 2289.80 cm−1, and the combination band ν2 + ν4, at 2386.61 cm−1, each of which give rise to a system of sum bands, difference bands, and hot bands involving the low-wave-number fundamental ν7 at 18 cm−1. A few other tentative assignments are made. The bands have been analyzed for vibrational and rotational constants

High-resolution infrared spectroscopy of 13C12CD2: the bending states up to v4+v5=2.

The high-resolution infrared spectrum of the deuterated isotopologue of acetylene, 13C12CD2, has been recorded by Fourier transform spectroscopy in the range 450 121800 cm 121. The bending fundamental bands and a number of overtone, combination and hot bands have been identified for both isotopomers. In total, 13 vibrational bands were analysed, involving all the l 12vibrational components of the excited bending states up to vt = v4 + v5 = 2. All the assigned transitions have been fitted simultaneously on the basis of a model Hamiltonian which takes into account the usual rotation and vibration l 12type resonances, together with the Darling-Dennison coupling between the v4 = 2 and v5 = 2 bending states. The ground state and 9 vibrationally excited states have been characterized. The spectroscopic parameters obtained from the least-squares procedure reproduce 1334 transitions with a standard deviations of the fit equal to 0.00037 cm 121. In addition, a few bands involving states of the vt = 3 manifolds have been identified and analysed