A Multi-Year Study of GOES-13 Droplet Effective Radius Retrievals for Warm Clouds over South America and Southeast Pacific

Geostationary satellites can retrieve the cloud droplet effective radius (re) but suffer biases from cloud inhomogeneities, internal retrieval nonlinearities, and 3-D scattering/shadowing from neighboring clouds, among others. A 1-D retrieval method was applied to Geostationary Operational Environmental Satellite 13 (GOES-13) imagery, over large areas in South America (+5∘ to −30∘ N5∘ N–30∘ S; −20∘ to −70∘E20∘–70∘ W), the Southeast Pacific (+5∘ to −30∘ N5∘ N–30∘ S; −70∘ to −120∘E70∘–120∘ W), and the Amazon (+2∘ to −7∘ N2∘ N–7∘ S; −54∘ to −73∘E54∘–73∘ W), for four months in each year from 2014–2017. Results were regressedcompared against in situ aircraft measurements and the Moderate Resolution Imaging Spectroradiometer cloud product for Terra and Aqua satellites. Monthly regression parameters approximately followed a seasonal pattern. With up to 108,009 of matchups, slope, intercept, and correlation for Terra (Aqua) ranged from about 0.71 to 1.17, −2.8 to 2.5 μm, and 0.61 to 0.91 (0.54 to 0.78, −1.5 to 1.8 μm, 0.63 to 0.89), respectively. We identified evidence for re overestimation (underestimation) correlated with shadowing (enhanced reflectance) in the forward (backscattering) hemisphere, and limitations to illumination/ and viewing configurations accessible by GOES-13, depending on the time of day and season. A proposition is hypothesized to ameliorate 3-D biases by studying relative illumination and cloud spatial inhomogeneity.

Gravitational decoupling of generalized Horndeski hybrid stars

Gravitational decoupled compact polytropic hybrid stars are here addressed in generalized Horndeski scalar-tensor gravity. Additional physical properties of hybrid stars are scrutinized and discussed in the gravitational decoupling setup. The asymptotic value of the mass function, the compactness, and the effective radius of gravitational decoupled hybrid stars are studied for both cases of a bosonic and a fermionic prevalent core. These quantities are presented and discussed as functions of Horndeski parameters, the decoupling parameter, the adiabatic index, and the polytropic constant. Important corrections to general relativity and generalized Horndeski scalar-tensor gravity, induced by the gravitational decoupling, comply with available observational data. Particular cases involving white dwarfs, boson stellar configurations, neutron stars, and Einstein–Klein–Gordon solutions, formulated in the gravitational decoupling context, are also scrutinized.

Genotype-Specific Lesion Growth Rates in Stargardt Disease

Reported growth rates (GR) of atrophic lesions in Stargardt disease (STGD1) vary widely. In the present study, we report the longitudinal natural history of patients with confirmed biallelic ABCA4 mutations from five genotype groups: c.6079C>T, c.[2588G>C;5603A>T], c.3113C>T, c.5882G>A and c.5603A>T. Fundus autofluorescence (AF) 30° × 30° images were manually segmented for boundaries of definitely decreased autofluorescence (DDAF). The primary outcome was the effective radius GR across five genotype groups. The age of DDAF formation in each eye was calculated using the x-intercept of the DDAF effective radius against age. Discordance between age at DDAF formation and symptom onset was compared. A total of 75 eyes from 39 STGD1 patients (17 male [44%]; mean ± SD age 45 ± 19 years; range 21–86) were recruited. Patients with c.3113C>T or c.6079C>T had a significantly faster effective radius GR at 0.17 mm/year (95% CI 0.12 to 0.22; p < 0.001 and 0.14 to 0.21; p < 0.001) respectively, as compared to those patients harbouring c.5882G>A at 0.06 mm/year (95% CI 0.03–0.09), respectively. Future clinical trial design should consider the effect of genotype on the effective radius GR and the timing of DDAF formation relative to symptom onset.

On longitudinal and transversal diffusion of carbon nanotubes

In this work, the anisotropy of diffusion of carbon nanotubes in water was studied by the molecular dynamics method. Two models of nanotubes were used, their lengths varied from 4 to 31 nanometers. The first model is a nanotube with armchair chirality, the second is connected solid nanoscale rods. The behavior of various components of the velocity autocorrelation function of the nanotubes center of mass has been studied. It was established that the transverse component of this function has a negative region and a minimum point, in contrast to the average autocorrelation function, which decays monotonically. It is shown that the diffusion coefficients in the longitudinal and transverse directions can differ several times; the method proposed in this work was used to determine them. The effect of anisotropy increases with an increase in the ratio of the characteristic sizes of the nanotube. Using the Stokes - Einstein formula, the effective hydrodynamic radii of nanotubes have been determined. In all cases, the effective radius is significantly less than the tube length.

Fragmenting Active Asteroid 331P/Gibbs

We describe active asteroid 331P/Gibbs (2012 F5) using archival Hubble Space Telescope (HST) data taken between 2015 and 2018. 331P is an outer main belt active asteroid with a long-lived debris trail that formed in 2011. Embedded in the debris trail we identify 19 fragments with radii between 0.04 and 0.11 km (albedo 0.05 assumed) containing about 1% of the mass of the primary nucleus. The largest shows a photometric range (∼1.5 mag), a V-shaped minimum, and a two-peaked lightcurve period near 9 hr, consistent with a symmetric contact binary. Less convincing explanations are that 331P-A is a monolithic, elongated splinter or that its surface shows hemispheric 4:1 albedo variations. The debris trail is composed of centimeter-sized and larger particles ejected with characteristic 10 cm s−1 speeds following a size distribution with index q = 3.7 ± 0.1 to 4.1 ± 0.2. The HST data show that earlier, ground-based measurements of the nucleus were contaminated by near-nucleus debris, which cleared by 2015. We find that the primary nucleus has effective radius 0.8 ± 0.1 km and is in rapid rotation (3.26 ± 0.01 hr), with a lightcurve range of 0.25 mag and a minimum density of 1600 kg m−3 if strengthless. The properties of 331P are consistent with (1) formation about 1.5 Myr ago by impact shattering of a precursor body, (2) spin-up by radiation torques to critical rotation, (3) ejection of about 1% of the nucleus mass in mid 2011 by rotational instability, and (4) subsequent evolution of the fragments and dispersal of the debris by radiation pressure.

Linear relationship between effective radius and precipitation water content near the top of convective clouds: measurement results from ACRIDICON–CHUVA campaign

Quantifying the precipitation within clouds is a crucial challenge to improve our current understanding of the Earth's hydrological cycle. We have investigated the relationship between the effective radius of droplets and ice particles (re) and precipitation water content (PWC) measured by cloud probes near the top of growing convective cumuli. The data for this study were collected during the ACRIDICON–CHUVA campaign on the HALO research aircraft in clean and polluted conditions over the Amazon Basin and over the western tropical Atlantic in September 2014. Our results indicate a threshold of re∼13 µm for warm rain initiation in convective clouds, which is in agreement with previous studies. In clouds over the Atlantic Ocean, warm rain starts at smaller re, likely linked to the enhancement of coalescence of drops formed on giant cloud condensation nuclei. In cloud passes where precipitation starts as ice hydrometeors, the threshold of re is also shifted to values smaller than 13 µm when coalescence processes are suppressed and precipitating particles are formed by accretion. We found a statistically significant linear relationship between PWC and re for measurements at cloud tops, with a correlation coefficient of ∼0.94. The tight relationship between re and PWC was established only when particles with sizes large enough to precipitate (drizzle and raindrops) are included in calculating re. Our results emphasize for the first time that re is a key parameter to determine both initiation and amount of precipitation at the top of convective clouds.

Fiber Optic-Based Thermal Integrity Profiling of Drilled Shaft: Inverse Modeling for Spiral Fiber Deployment Strategy

The current state of practice to interpret the thermal integrity profiling (TIP) data of drilled shaft is the so-called effective radius method. It uses the concrete pouring log and average temperature to construct a relationship between temperature distribution and effective radius that can be used to reconstruct a drilled shaft model. While this effective radius method is computationally inexpensive and has good operationality, it is not good at predicting the dimensions and shape of shaft defects. Upgrading the sensor used in conventional TIP from thermocouples/thermal wires to fiber optic sensors, the spatial resolution of the measured temperature will be enhanced. By using the newly proposed spiral fiber deployment strategy, we can improve the reconstruction of shaft defects in the integrity testing of drilled shafts. The corresponding inverse modeling of defected shaft reconstruction for spiral deployment is proposed in this paper based on the temperature distribution pattern that is learned from forward modeling. Through inverse modeling, the details of defects in drilled shafts can be reconstructed numerically. An analysis of the results shows that the prediction by inverse modeling has good agreement with the forward modeling set up initially. This work helps the evolution of the TIP from the nondestructive testing stage to the quantitative nondestructive evaluation stage.