A Predominant Cause of Recurrence of Ventilator-Associated Pneumonia in Patients with COVID-19 Are Relapses.

The diagnosis of ventilator-associated pneumonia (VAP) recurrence in patients with coronavirus disease 2019 (COVID-19) pneumonia is challenging, and the incidence of recurrence is high. This study aimed to investigate the incidence and recurrence of VAP. Furthermore, we investigated the causative microorganisms of VAP and recurrent VAPs in patients with COVID-19.

Retention of microplastics in a major secondary wastewater treatment plant in Vancouver, Canada.

Municipal wastewater treatment plants (WWTPs) are conduits through which microplastics (MPs) are released into aquatic environments. However, the technical challenges in working with wastewater sample matrices have precluded reliable particle count budget calculations. We applied newly-adapted methods for MP collection and analysis to a study of a major WWTP serving a population of 1.

Impact of parental weight status on a school-based weight management programme designed for Mexican-American children.

Background: While overweight and obese children are more likely to have overweight or obese parents, less is known about the effect of parental weight status on children's success in weight management programmes.

Objectives: This study was a secondary data analysis of a randomized controlled trial and investigated the impact of having zero, one or two obese parents on children's success in a school-based weight management programme.

Methods: Sixty-one Mexican-American children participated in a 24-week school-based weight management intervention which took place in 2005-2006.

[60]Fullerene-based liquid crystals acting as acid-sensitive fluorescent probes.

Functionalization of [60]fullerene with liquid-crystalline dendrimers and a dibutylaniline-based phenylenevinylene moiety leads to supramolecular materials, the fluorescence of which responds to acid-base stimuli.

Method for correcting the wavelength misalignment in measured ultraviolet spectra.

A new method for correcting the wavelength misalignment in measured UV spectra is presented. It is based on a comparison between measured irradiances and irradiances computed from a radiative transfer code for a set of given atmospheric and solar conditions (250 < Dobson units < 450, 30 degrees < solar zenith angle < 75 degrees ). Results of tests run with spectra recorded on a clear-sky day by two spectroradiometers in a French UV spectral network station are analyzed.

Influence of the environment reflectance on the ultraviolet zenith radiance for cloudless sky.

A three-dimensional Monte Carlo code is used to compute the ultraviolet zenith sky radiance; the code is validated by comparison with a successive-orders-of-scattering code. The amplifications of global irradiance, diffuse irradiance, and zenith radiance that are due to multiple reflectances between a snow-covered ground surface and the atmosphere are compared. For an inhomogeneous Lambertian surface, the contribution of the site environment is analyzed; it depends slightly on the atmospheric turbidity and on the surface reflectance distribution.

Methodology for the independent calibration of Raman backscatter water-vapor lidar systems.

We present a method for the independent calibration of Raman backscatter water-vapor lidar systems. Particular attention is given to the resolution of instrumental changes in the short and the long terms. The method reposes on the decomposition of the instrument function, which allows the lidar calibration coefficient to be re-expressed as the product of two terms, one describing the instrumental transmission and detection efficiency and the other describing the wavelength-dependent convolution of the Raman backscatter cross sections with the instrument function.

Validation of the ORA spatial inversion algorithm with respect to the Stratospheric Aerosol and Gas Experiment II data.

We present the results of a comparison of the total extinction altitude profiles measured at the same time and at same location by the ORA (Occultation Radiometer) and Stratospheric Aerosol and Gas Experiment II solar occultation experiments at three different wavelengths. A series of 25 events for which the grazing points of both experiments lie within a 2 degrees window has been analyzed. The mean relative differences observed over the altitude range 15-45 km are -8.

Modeling of the influence of snow reflectance on ultraviolet irradiance for cloudless sky.

The amplification of UV irradiance at the Earth's surface that is due to successive reflections between the snow-covered ground and the scattering atmosphere is analyzed by a method based on decoupling the atmosphere and the surface functions. For a uniform Lambertian surface the amplification factor for the global irradiance depends only on the product of the surface reflectance and the atmospheric backscatter. It varies with wavelength, reaching a maximum near 320 nm; this maximum is close to 50% for clean snow.

Variability of UV irradiance in Europe.

The diurnal and annual variability of solar UV radiation in Europe is described for different latitudes, seasons and different biologic weighting functions. For the description of this variability under cloudless skies the widely used one-dimensional version of the radiative transfer model UVSPEC is used. We reconfirm that the major factor influencing the diurnal and annual variability of UV irradiance is solar elevation.

Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering.

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2.

Liquid-crystalline Janus-type fullerodendrimers displaying tunable smectic-columnar mesomorphism.

Janus-type liquid-crystalline fullerodendrimers were synthesized via the 1,3-dipolar cycloaddtition of two mesomorphic dendrons and C60. By assembling poly(aryl ester) dendrons functionalized with cyanobiphenyl groups, displaying lamellar mesomorphism, with poly(benzyl ether) dendrons carrying alkyl chains, which display columnar mesomorphism, we could tailor by design the liquid-crystalline properties of the title compounds as a function of each dendron size. The liquid-crystalline properties were examined by polarized optical microscopy, differential scanning calorimetry, and X-ray diffraction.

Liquid-crystalline bisadducts of [60]fullerene.

A second-generation cyanobiphenyl-based dendrimer was used as a liquid-crystalline promoter to synthesize mesomorphic bisadducts of [60]fullerene. Liquid-crystalline trans-2, trans-3, and equatorial bisadducts were obtained by condensation of the liquid-crystalline promoter, which carries a carboxylic acid function, with the corresponding bisaminofullerene derivatives. A monoadduct of fullerene was also prepared for comparative purposes.

Liquid-crystalline fullerodendrimers which display columnar phases.

[structure: see text] The title compounds were synthesized by applying the 1,3-dipolar cycloaddition reaction of aldehyde-based poly(benzyl ether) dendrimers and sarcosine (N-methylglycine) to [60]fullerene (C(60)). The dendritic building blocks used to functionalize C(60) displayed cubic and hexagonal columnar phases. The fullerene derivatives showed rectangular columnar phases of c2mm symmetry.

Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment.

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2.

Analysis of direct solar ultraviolet irradiance measurements in the French Alps. Retrieval of turbidity and ozone column amount.

Direct ultraviolet spectral solar irradiance is regularly obtained by the difference between global and diffuse irradiances at the French Alpine station of Briançon; the data of years 2001 and 2002 are analyzed in this paper. Comparison with modeled values is used for cloud screening, and an average UV-A aerosol optical depth is used as an index of turbidity; it is found to be around 0.05 for the clear winter days and around 0.

Retrieval of the ultraviolet effective snow albedo during 1998 winter campaign in the French Alps.

A measurement campaign was carried out in February 1998 at Briançon Station, French Alps (44.9 degrees N, 6.65 degrees E, 1,310 m above sea level) in order to determine the UV effective snow albedo that was retrieved for both erythemal and UV-A irradiances from measurements and modeling enhancement factors.

Retrieval of the ultraviolet aerosol optical depth during a spring campaign in the Bavarian Alps.

A measurement campaign was organized in March 1999 in the Bavarian Alps as part of the European project, Characteristics of the UV Radiation Field in the Alps (CUVRA), to analyze the effect of altitude, aerosols, and snow cover on ground-level UV spectral irradiance. We present the results of simultaneous measurements of aerosol optical depth (AOD) made at various sites on two cloudless days in March 1999. The two days exhibited different aerosol conditions.

Comparison between measurements and modeling of UV-B irradiance for clear sky: a case study.

We compare the TJV-B global and direct irradiances computed with a radiative transfer model (discrete ordinate method) and measured during a European intercomparison campaign in Greece in July 1991, with clear sky. The agreement between the model and the measurements is within 6%. The sensitivity of the model to the accuracy of the input parameters as well as the potential of modeling for instrument calibration is discussed.

Absorption profile of a planetary atmosphere: a proposal for a scattering independent determination.

The use of scattering theory to infer atmospheric optical parameters requires the separation of absorption and scattering. It is demonstrated that a gradient flux relation exists that would provide the absorption (altitude) profile independently of scattering and irrespective of the state of polarization of the light field. The relation is derived for an atmosphere of plane-parallel or spherical geometry and for broad (continuum) and narrow (spectral line) frequency bands.