Refractive Profile Research Articles

Short-Range Prediction of Squall-Line-Induced Heavy Rainfall: An Added Impact of GPS RO to FY-4A AGRI Data Assimilation

Abstract The GPS radio occultation technique has prompted a new era as GPS receivers are placed onboard traditional polar-orbiting operational environmental satellites and newly emerging commercial small satellite constellations. With high vertical resolutions of a few hundred meters, GPS radio occultation-observed refractivity profiles effectively complement the geostationary satellite observations of infrared brightness temperatures at high horizontal resolutions (∼2 km) for data assimilation in numerical weather prediction. In this study, numerical experiments are performed to assimilate radio occultation (RO) refractivity observations from FY-3D/FY-3E, MetOp-B/MetOp-C, COSMIC-2, SPIRE, and GeoOptics and brightness temperature observations at channels 9 (6.25 μm) and 10 (7.1 μm) from the Advanced Geosynchronous Radiation Imager (AGRI) onboard FY-4A. The benefits of adding the refractivity to the brightness temperature observations for improving quantitative precipitation forecasts (QPFs) of two squall-line cases over eastern China are shown using the Weather Research and Forecasting Model and the Gridpoint Statistical Interpolation analysis system. In the first case, the squall line was caused by a superposition of cold and dry air advection behind an upper-level trough over low-level warm and humid air by a low-level jet. A combined assimilation of the GPS RO and FY-4A AGRI observations produced a skillful forecast of the squall-line distribution, characterized by a warm zone 100–300-km long ahead of a cold front near the ground; this led to more consistent improvements in the forecast of a narrow band of squall-line thunderstorms than those from two separate assimilations. The threat scores of 24-h QPFs associated with both squall-line cases are significantly improved, especially for heavier rainfall events.

Peripheral refraction of young adults with myopia: a cross-sectional study.

Peripheral refraction is associated with myopia development. Due to a varying prevalence of myopia across different ethnic groups, the aim of the present study was to investigate the peripheral refraction profile in an Arabic population. Adults attending an optometry clinic were recruited into this cross-sectional study. Peripheral refraction of the right eyes was measured using an open field autorefractor under noncycloplegic conditions along the temporal-nasal meridians (15° and 35°) in participants with emmetropia, or low, moderate, or high myopia. Refractions were converted into power vector components, including the spherical equivalent of central refraction, J0 and J45 astigmatism. STROBE guidelines were followed for study reporting. A total of 138 adults (aged 20-29 years) were enrolled. Relative peripheral refractive error (RPRE) varied between refractive groups and increased with eccentricity. The RPRE was more hyperopic in myopia groups, with the nasal visual field being more hyperopic. A significant relationship was found between RPRE and central refraction, but not with J0 and J45 scores. Participants with moderate myopia exhibited more hyperopic RPRE compared with previous findings in other ethnic groups. Hyperopic RPRE was significantly associated with myopia. Accurate RPRE measurement are essential for designing personalized lenses to slow down myopia progression. This study provides an RPRE baseline in the population investigated, which will be useful for future studies on personalized lens design, including spectacles and contact lenses.

Analysis of the Liquefaction Potential at the Base of the San Marcos Dam (Cayambe, Ecuador)—A Validation in the Use of the Horizontal-to-Vertical Spectral Ratio

Ground liquefaction potential analysis is a fundamental characterization in areas with continuous seismic activity, such as Ecuador. Geotechnical liquefaction studies are usually approached from dynamic penetration tests, which pose problems both in their correct execution and in their evaluation. Our research involves analyzing dynamic penetration tests and microtremor geophysical surveys (horizontal-to-vertical spectral ratio technique, HVSR) for analyzing the liquefaction potential at the base of the San Marcos dam, a reservoir located in Cayambe canton (Ecuador). Based on the investigations performed at the time of construction of the dam (drilling and geophysical refraction profiles) and the application of 20 microtremor observation stations via the HVSR technique, an analysis of the safety factor of liquefaction (SFliq) was conducted using the 2001 Youd and Idriss formulation and the values of the standard penetration test (SPT) applied in granular materials (sands). In addition, the vulnerability index (Kg) proposed by Nakamura in 1989 was analyzed through the HVSR records related to the ground shear strain (GSS). The results obtained in the HVSR analysis indicate the presence of a zone of about 100 m length in the central part of the foot of the dam, whose GSS values identified a condition of susceptibility to liquefaction. In the same area, the SPT essays analysis in the P-8A drill hole also shows a potential susceptibility to liquefaction in earthquake conditions greater than a moment magnitude (Mw) of 4.5. That seismic event could occur in the area, for example, with a new activity condition of the nearby Cayambe volcano or even from an earthquake from the vicinity of the fractured zone.

NEW APPROACHES TO CROSSLINKING IN COMBINATION WITH REFRACTIVE KERATOMODELING IN CORNEAL ECTASIA

Objective: To consider new approaches to crosslinking in combination with refractive keratomodeling in corneal ectasia of various etiologies.Methods: The work is based on clinical observations of the immediate and remote results of prophylactic and therapeutic corneal crosslinking with argon-fluorine excimer laser radiation (over 700 operations) over periods from 1 month to 13 years. Particular emphasis was placed on the formation of a Bowman-like membrane structure on the ablation surface and local exposure with a personalized gradient refractive profile of the total dose of radiation to achieve a greater keratomodeling effect. Rapid transition without additional calibrations to energy densities below the ablation threshold was carried out on the Russian excimer laser “Microscan Visum-500”.Results: Experimental and clinical studies have shown that excimer laser radiation on argon-fluorine can be used for corneal crosslinking, with energy densities in the pulse being below the ablation threshold. The advantage of excimer laser crosslinking was scanning with a narrow beam, which disrupts the oxygenation of the corneal stroma to a lesser extent and allows for the implementation of personalized local refractive keratomodeling based on keratotopography or aberrometry data. In this case, the induced secondary radiation covers all four peaks of maximum absorption by riboflavin. The use of subablative energy densities during irradiation of the cornea in the personalized PRK mode made it possible to locally affect the ectasia zone and enhance the refractive effect due to the gradient distribution of the total radiation dose.Conclusion: Radiation from an argon-fluorine excimer laser opens up new possibilities for refractive ablative and non-ablative refractive keratomodeling of the cornea in combination with laser-induced crosslinking in keratoconus and secondary keratoectasias of various etiologies.

Refractive Profiles in Children Receiving School-Based Eye Exams Following Vision Screening from a Large School-Based Vision Program in 2016 to 2022

ABSTRACT Purpose To describe refractive error findings and associated factors in students who received school-based eye exams following vision screenings. Methods Cross-sectional study of pre-kindergarten through 12th grade students who failed vision screening and underwent a school-based eye exam in the Northeast region of the United States during 2016–2022. Non-cycloplegic autorefraction and visual acuity measurements were used to categorize refractive error by type and severity. Main outcomes included any refractive error (at least −0.50D myopia, +0.50 hyperopia, 1.00D astigmatism, or 1.00D anisometropia), clinically significant refractive error (CSRE; more severe refractive error with decreased vision), and refractive amblyopia risk (RAR). Multivariable mixed-effects logistic regression was used to determine student- and school-level characteristics associated with refractive error outcomes. Results Of 103,159 included students who failed screening, 95,875 (92.9%) were analyzed. Overall prevalence of any refractive error was 94.2%, with 81.7% having CSRE. Pre-kindergarten & kindergarten students had the highest prevalence of CSRE (85.7%), which dropped to 77.0% by 3rd and 4th grade before rising with each higher grade level thereafter. Prevalence of RAR was 60.9% overall and highest in pre-kindergarten and kindergarten students (73.8%). Myopia was the most prevalent refractive error, followed by astigmatism, anisometropia, then hyperopia. The odds of hyperopia, astigmatism, and anisometropia decreased with higher grade level. Conclusion Over 80% of students who failed vision screening at a large school-based vision program had CSRE, and over 60% had RAR. Pre-kindergarten and kindergarten students had an especially high prevalence of RAR. Refractive error remained common in every grade level.

Physical mechanisms of femtosecond laser induced refractive index change in direct-written mid-infrared fiber Bragg gratings

Femtosecond laser inscription of fluoride Fiber Bragg Gratings (FBGs) has enabled the realization of all-fiber laser sources at mid-infrared wavelengths. However, many fundamental aspects of the fabrication process remain unknown, which hinders further development. In this paper, we for the first time reveal the physical mechanisms that underpin the laser-induced permanent refractive index change in the periodic grating elements that constitute an FBG. Quadriwave lateral shearing interferometry and micro-reflectivity measurements are introduced as techniques for the full characterization of the refractive index change profile of the grating structure. The fundamental processes that eventually result in a permanent index change were found to differ significantly between the chemically closely related fluoroindate and fluorozirconate glass families. In fluoroindate fibers, the index change can almost entirely be attributed to elemental migration, whereas in fluorozirconate fibers the involved processes are more intricate and include the selective migration of fluorine ions as well as the formation of F-centers, more specifically unpaired electrons trapped in anion vacancies. In addition, in fluorozirconate fibers, the formation of dynamic stress regions in-between the grating planes was observed, more specifically a build-up of higher stress in areas adjacent to positive index-change regions and of lower stress in areas adjacent to negative index-change regions, which for the first time explains the unusual annealing behavior of mid-IR FBGs.

Refractive errors, amblyopia risk factors and vision screening in children aged 7–10 years in Aotearoa New Zealand

ABSTRACT Clinical relevance Vision screening is important for detecting undiagnosed vision conditions that are common in school-aged children. However, current vision screening protocols are poor at detecting vision conditions that are most common in the Aotearoa New Zealand paediatric population. Background Uncorrected refractive error and amblyopia are the most common causes of visual impairment in children. The most appropriate vision screening method depends on the refractive error profile of the population. This study aimed to: estimate the prevalence of refractive errors and amblyopia risk factors among children living in Aotearoa New Zealand; describe previous participation in preschool vision screening and determine the diagnostic accuracy of potential screening methods. Methods Children aged 7–10 years received comprehensive eye examinations, including cycloplegic refraction, in their school. Eye examination results were assessed for refractive error and amblyopia risk factors. The sensitivity and specificity of individual vision tests for detecting any vision conditions was calculated to assess the most effective tests for vision screening. Results Eye examinations were completed for 237 children and cycloplegic refraction data was available for 220 of these children. Significant refractive error (need for glasses) was detected in 23.6% of children (7.7% myopia, 7.7% hyperopia, 15.0% astigmatism). Amblyopia risk factors were detected in 9.1% of children. Preschool vision screening had been completed by 78.5% of children. Distance visual acuity screening alone had a sensitivity of 39% for detecting vision conditions, with addition of the Spot Vision Screener improving sensitivity to 65%. Conclusion Astigmatism is the most frequent refractive error among children aged 7–10 years living in Aotearoa New Zealand. Distance visual acuity screening alone is ineffective in detecting refractive error in children in Aotearoa New Zealand. Further research investigating refractive errors across the paediatric population in Aotearoa New Zealand is required to determine the optimal timing and appropriate protocols for school-aged vision screening.

Changes in Axial Length and Refractive Profile in Different Illumination: A Comparative Study to Understand the Impact of Myopia Control

Purpose: The purpose of the study was to evaluate and compare the changes in axial length and refractive profile in myopic patients exposed with different illumination. Methodology: A cross-sectional study among 15 myopic subjects was conducted in the tertiary eye care institute. Before participating in the study, individuals underwent comprehensive ocular examinations to ensure their suitability. For each participant, the experiment was conducted in two phases: Phase I procedures occurring at the initial visit and Phase II procedures taking place 1 week later. In Phase I, baseline measurements of axial length and refractive profiles were taken for all participants, followed by exposure to illumination below 500 Lux for 30 min. Phase II replicated the baseline measurements, followed by exposure to lighting above 1000 Lux for the same duration. Axial length measurements were performed using Lenstar LS-500, and refractive profiles were determined using an autorefractometer, both administered by experienced optometrists. Three consecutive measurements were taken for each eye, and the average value was recorded for both axial length and refractive parameters. Paired t-test was used to compare axial length measurements at baseline and after exposure to different illumination levels. Linear regression was used to determine the association between axial length and illumination levels. Statistical significance was considered if P < 0.05. Results: Mean axial length measurements varied across the two illumination groups: 23.62 ± 0.18 mm in the high illumination group (>1000 lux) and 23.96 ± 0.23 mm in the low illumination group (<500 lux). Paired t-test revealed a significant difference in axial length among the groups (P = 0.01). Similarly, the mean spherical equivalent refractive error also varied significantly across the illumination groups: −1.52 ± 0.60 Diopter (D) in the high illumination group, and − 2.01 ± 0.16 D in the low illumination group. There was a significant negative correlation between axial length and refractive error for high illumination group. Conclusion: Higher levels of illumination were associated with shorter axial length and less myopic refractive error in individuals.

Assessment of Commercial GNSS Radio Occultation Performance from PlanetiQ Mission

Global Navigation Satellite System (GNSS) radio occultation (RO) provides valuable 3-D atmospheric profiles with all-weather, all the time and high accuracy. However, GNSS RO mission data are still limited for global coverage. Currently, more commercial GNSS radio occultation missions are being launched, e.g., PlanetiQ. In this study, we examine the commercial GNSS RO PlanetiQ mission performance in comparison to KOMPSAT-5 and PAZ, including the coverage, SNR, and penetration depth. Additionally, the quality of PlanetiQ RO refractivity profiles is assessed by comparing with the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5) data in October 2023. Our results ensure that the capability of PlanetiQ to track signals from any GNSS satellite is larger than the ability of KOMPSAT-5 and PAZ. The mean L1 SNR for PlanetiQ is significantly larger than that of KOMPSAT-5 and PAZ. Thus, PlanetiQ performs better in sounding the deeper troposphere. Furthermore, PlanetiQ’s average penetration height ranges from 0.16 to 0.49 km in all latitudinal bands over water. Generally, the refractivity profiles from all three missions exhibit a small bias when compared to ERA5-derived refractivity and typically remain below 1% above 800 hPa.

Refractive power profiles of commercially available soft multifocal contact lenses for myopia control.

Lens power profiles can provide valuable insights on the imposed optical defocus and visual experience of contact lens wearers, especially in the context of myopia control. This study measured the refractive power profiles of multifocal soft contact lenses (MFCLs) currently used or that have the potential for use in myopia control using high spatial resolution aberrometry. The instrument's repeatability for determining MFCLs power profiles was also assessed. The power profiles of 10 MFCLs of various designs (centre-distance, centre-near and extended depth of focus) were measured using the Lambda-X NIMOEVO, a phase shifting Schlieren-based device. Power profiles were graphically expressed as measured power at each chord position and the maximum add power was calculated. The repeatability of the NIMOEVO was expressed as the within-subject standard deviation at each chord position for a subset of five MFCLs. The measured distance powers differed from nominal powers for more than half of the MFCLs with a definable distance zone. There were variations in the chord position of the distance and near correction zones, rate of power transitions and calculated maximum add between the MFCLs which did not depend on lens design. For half of the MFCLs, the power profile shape was inconsistent between different nominal back vertex powers of the same design. The repeatability of the NIMOEVO was dependent on the lens design, with designs featuring faster rates of power change exhibiting worse repeatability. Significant differences in MFCL power profiles were found which were not adequately represented in labelling. This is likely due to the small number of parameters used to define lens power characteristics. Eye health care practitioners should be aware of potential differences in power profiles between different MFCLs, which will impact the retinal defocus introduced during lens wear and the wearer's visual experience.

First Results of Airborne GNSS Radio Occultation Sounding From Airbus Commercial Aircraft

AbstractThe lack of high vertical resolution atmospheric thermodynamic structure observations inside or near major weather events impedes our understanding of physical processes and their predictability in numerical weather prediction (NWP) models. Airborne Global Navigation Satellite System (GNSS) radio occultation (airborne radio occultation [ARO]) has proven to be a viable remote sensing option to offer dense soundings near flight tracks. The global fleet of commercial aircraft already equipped with GNSS receivers could be leveraged to produce an unprecedented number of ARO soundings along global flight paths. Eleven cases of atmospheric bending angle and refractivity profiles were successfully retrieved and compared with the colocated European Center for Medium‐Range Weather Forecasting global reanalysis data. Good quality measurements are obtained with median refractivity differences less than 1% in the middle and upper troposphere, between 5.5 and 11.5 km. Given the use of aircraft data (e.g., Aircraft Meteorological DAta Relay) for data assimilation, incorporating ARO profiles would be a valuable addition, further enhancing the accuracy of aviation and weather forecasts.

Investigation and monitoring of rotational landslides in El Mokkattam plateau Egypt, using integrated geological and geophysical techniques

Landslides are a rare but hazardous geological phenomenon in Egypt, with the El Mokattam plateau situated in the eastern part of Cairo covering approximately 64 km2 and ranging in elevation from 50 to 205 m. This study aims to identify and monitor landslides in the area using various geophysical methods. Twelve Electrical resistivity tomography (ERT) profiles,twenty-two P-wave Seismic Refraction profiles, twenty-two Refraction microtremors profiles, three ground penetrating radar (GPR) profiles and borehole data were utilized to analyze the occurrence of landslides in the El Mokattam Plateau. Additionally, we employed a relatively new geophysical method, studying high-frequency microtremor sounds emitted from landslide collapses at 22 stations. Our analysis identified steep slopes, jointed or fractured rocks, and irrigation water as primary factors contributing to landslides, with irrigation water acting as a lubricant for clays and promoting ground sliding. Examination of high-frequency microtremor sounds revealed a potential correlation between vertical high-frequency spectra at 100 Hz and landslide collapses, which aids in the identification of landslide-prone zones. Therefore, we conclude that seismological studies, particularly spectral analysis of high-frequency and low-amplitude sounds (microtremors) emitted from soil, offer a promising approach for investigating landslides.

Myopia dominance in preterm infants without and with retinopathy of prematurity: Indian Twin Cities ROP study (ITCROPS) report number 15.

To investigate the refractive error profile and progression in infants with different stages of ROP, without ROP, and those who received laser treatment for ROP. This retrospective study included the data from 838 infants (baseline mean age 3.7 ± 5.4 months) who had premature birth. Among these, 433 infants had one of the stages of ROP and 405 had no ROP. Infants with ROP were sub-divided into stage 1 (n = 76), stage 2 (n = 142), and stage 3 (n = 136) and aggressive posterior ROP, (APROP, n = 79). They were further categorized into those who received treatment (n = 213) and with no treatment for ROP (n = 220). Data from a subset of 117 infants was used to assess the 1-year change in the refractive error. Myopia was defined as spherical equivalent refraction (SER) <-0.50 diopters (D). Eyes with retinal detachment were excluded. Higher percentage of myopia was found in infants with ROP (39.7%) than no-ROP (19.8%), and it increased with severity of ROP: stage 1: 19.7%, stage 2: 33.8%, stage 3: 45.6%, and 59.5% in APROP. Percentage of myopia doubled in those who underwent treatment for ROP (54.5%) compared to no-treatment group (25.5%). Mean (± SEM) change in SER after 1 year was significantly greater in infants with APROP -4.55 ± 1.38 D and stage 3 ROP -2.28 ± 0.57 D compared to other stages and no-ROP. Myopia was found to be more prevalent in preterm infants in general, and more in the presence of ROP. Preterm infants without or with any form of ROP, particularly those with severe form of ROP and those who received treatment require meticulous periodic refractive error assessment.

Association between vision-related quality of life and mental health status in myopia children using various optical correction aids

PurposeTo evaluate the relationship between vision-related quality of life and mental health in myopia children with various optical aids. MethodsThis cross-sectional study enrolled children aged 8–13 years, exhibiting myopia ranging from −4.50 to −0.75 D, and utilizing various optical aids for correction. Full ocular examinations and completion of two questionnaires were performed. Vision-related quality of life was evaluated using the Paediatric Refractive Error Profile (PREP), and mental health status was assessed utilising the Screen for Child Anxiety Related Emotional Disorders (SCARED). Univariate and multivariate analyses were conducted to evaluate the association between vision-related quality of life and mental health status. ResultsThe study sample comprised 209 children with corrected myopia using single vision spectacles (100 [47.8 %]), soft contact lenses (66 [31.6 %]), and orthokeratology lenses (43 [20.6 %]). The mean age was 10.31 ± 1.65 y, and males accounted for 50.7 % of the sample. The distribution of demographic characteristics showed no significant difference among all correction types, except that the myopia duration was longer for orthokeratology lens wearers than those using spectacles (P=0.03). Contact lens showed clear benefits in almost all dimensions of vision-related quality of life, especially in appearance, satisfaction, activity and peer perceptions dimensions. The prevalence of anxiety disorders among spectacle wearers was 25.0 %, the highest among all groups. For myopia children with optical corrections, not being in the top 30 percent of their class rank, reporting lower PREP scores on symptoms, handling and peer perceptions dimensions were related with a higher prevalence of anxiety disorders. ConclusionsLower vision-related quality of life was associated with worse mental health status of myopia children with optical corrections. Identifying this association is crucial for protecting the mental health of myopia children and enhancing corrective measures.

УСВОЕНИЕ ДАННЫХ РАДИОЗАТМЕННЫХ НАБЛЮДЕНИЙ В ЧИСЛЕННОМ ПРОГНОЗЕ ПОГОДЫ

The paper discusses the principles of the assimilation of radio occultation observations into numerical weather prediction models. The most widely used approach is assimilation of the bending angle profiles obtained from the observations by the wave optics methods. The observation operators are constructed from the geometric optics equations and can be three-dimensional (3D), taking into account the actual field of meteorological parameters, or one-dimensional (1D), using only one vertical profile. In the approximation of weak gradients, the 3D operator is reduced to the two-dimensional (2D) one, which takes into account the section of the fields of meteorological parameters by the vertical plane of the occultation event. Another approach is the assimilation of the retrieved atmospheric refractivity profiles by means of a simplest 1D or more accurate 2D operator. Some examples of statistical comparisons of the profiles of temperature, pressure, and specific humidity obtained by variational assimilation with the GFS reanalysis data are given.

Data Assimilation Impact of GNSS RO Measurements from Cube Satellites on Arctic Weather Forecasts

Abstract In this study, the effects of assimilating Global Navigation Satellite System (GNSS) radio occultation (RO) observations from existing and recently added commercial cube satellites on analyses and forecasts over the Arctic region were investigated by conducting observing system experiments (OSEs). Profiles of refractivity were assimilated with a local observation operator using the three-dimensional variational method. The analyses and forecasts from the OSEs were verified against ERA5 reanalysis, radiosonde observations, and buoy observations. In addition to the averaged impact on forecast skill, the impact of GNSS RO observations was further examined for an individual Arctic cyclone case, focusing on the added value of the cube satellite data. The effects of GNSS RO observations from existing satellites on analyses and forecasts over the Arctic region are positive, and the assimilation of GNSS RO observations from cube satellites leads to additional improvements, particularly for temperature in the upper troposphere and lower stratosphere (UTLS). Temperature biases in the UTLS are significantly reduced in the analyses, and the improved analyses result in better forecasts of upper-level potential vorticity and cyclone development when GNSS RO observations from cube satellites are assimilated. This result demonstrates the potential of GNSS RO data from cube satellites to enhance forecasts over the Arctic region.

Terahertz time-domain transmission spectroscopy of water and hydrogel thin films: Extraction of optical parameters and application to agarose gel characterization

Terahertz time-domain spectroscopy (THz-TDS) is an emerging optical technique that has potential applications in the characterization of (bio)materials. However, the complicated extraction of optical parameters from multi-layered and optically thin samples is a barrier towards its acceptance by applied scientists. Therefore, the aim of this work is to provide a straightforward approach for the extraction of the THz absorption coefficient and index of refraction profiles of aqueous thin films in a window-sample-window configuration, which is ubiquitous in many laboratories (i.e., sample in a cuvette). A numerical approach-based methodology that accounts for multiple layers, Fabry–Pérot effect, and sample thickness is elaborated which involves an optical interference model based on a tri-layer structure and a simple thickness estimation technique. This method was validated on water samples where a good agreement was found with the THz optical parameters of water reported in the literature, while the use of a commercial software resulted in erroneous optical parameters estimates when used without due regard to its limitations. A case study was then performed to demonstrate the ability of the proposed method to characterize agarose hydrogels with varying degree of sulfation. It was demonstrated that THz-TDS can provide insight into the hydration state of the agarose hydrogels, including the relative number of the hydrogen bonds between the hydroxyl moieties of water and the polysaccharide network which is perturbed by the presence of sulfate. The trend in the index of refraction profiles suggested microstructural differences between the agarose hydrogels, which were confirmed by visualizing the agarose network morphology using cryo-SEM imaging.

PlanetiQ Radio Occultation: Preliminary Comparative Analysis of Neutral Profiles vs. COSMIC and NWP Models

Radio Occultation (RO) is pivotal for profiling the neutral and ionized atmosphere, with the PlanetiQ mission, via its GNOMES satellites, striving to establish an advanced atmospheric observing system. However, an assessment of the spatiotemporal distributions of PlanetiQ observations and comparisons with reliable datasets are lacking. This study addresses this gap by examining the temporal and spatial distribution of RO observations from PlanetiQ during its initial 198 operational days in 2023, alongside comparisons with COSMIC and Numerical Weather Prediction (NWP) models. Data from GN02, GN03, and GN04 satellites, yielding 1099, 1313, and 1843 RO events per day, respectively, were analyzed. The satellite constellation’s observations demonstrate a generally well-distributed pattern, albeit minor deficiencies in equatorial and polar regions. Single-profile comparisons with COSMIC data reveal strong correlations for pressure, temperature, Water Vapor Pressure (WVP), and refractivity profiles, with temperature exhibiting larger variations (RMSE = 1.24 °C). Statistical analyses confirm statistically insignificant differences between the PlanetiQ and COSMIC profiles at the same spatio-temporal coordinates. Comparisons with NWP models show slight differences with GFS, with overall RMSE values of 0.23 mb (WVP), 0.6 mb (pressure), 1.3 (refractivity), and 1.5 °C (temperature). However, assessments against GFS/ECMWF models indicate overall compatibility, with insignificant differences between PlanetiQ profiles and model observations.

Exact wave solver for nonparaxial laser beam propagation

Simulations of inertial confinement fusion (ICF) experiments require high-fidelity models for laser beam propagation in a nonuniform plasma with varying index of refraction. We describe a new numerical wave solver that is applicable to centimeter-scale length plasmas encountered in indirect drive ICF applications. The one-way Helmholtz equation (OHE) generalizes the time-harmonic paraxial wave equation to large angles. Here, we present a methodology to numerically evaluate the exact solution to the OHE. This solution is computed by analytically advancing eigenfunctions of the one-way Helmholtz operator along a propagation direction and is applicable to any given index of a refraction profile. We compare our exact method with a commonly used approximate split-step technique for solving the OHE. As a test problem, we consider nonparaxial propagation of Gaussian and speckled beams in a plasma density channel with internal reflection. We find that the split-step approach incurs significant errors compared to the exact solution computed using the novel algorithm.

Enhancement of the Inner Foveal Response of Young Adults with Extended-Depth-of-Focus Contact Lens for Myopia Management.

Myopia management contact lenses have been shown to successfully decrease the rate of eye elongation in children by changing the peripheral refractive profile of the retina. Despite the efforts of the scientific community, the retinal response mechanism to defocus is still unknown. The purpose of this study was to evaluate the local electrophysiological response of the retina with a myopia control contact lens (CL) compared to a single-vision CL of the same material. The retinal electrical activity and peripheral refraction of 16 eyes (16 subjects, 27.5 ± 5.7 years, 13 females and 3 males) with myopia between -0.75 D and -6.00 D (astigmatism < 1.00 D) were assessed with two CLs (Filcon 5B): a single-vision (SV) CL and an extended-depth-of-focus (EDOF) CL used for myopia management. The peripheral refraction was assessed with an open-field WAM-5500 auto-refractometer/keratometer in four meridians separated by 45° at 2.50 m distance. The global-flash multifocal electroretinogram (gf-mfERG) was recorded with the Reti-port/scan21 (Roland Consult) using a stimulus of 61 hexagons. The implicit time (in milliseconds) and response density (RD, in nV/deg2) of the direct (DC) and induced (IC) components were used for comparison between lenses in physiological pupil conditions. Although the EDOF decreased both the HCVA and the LCVA (one and two lines, respectively; p < 0.003), it still allowed a good VA. The EDOF lens induced a myopic shift in most retinal areas, with a higher and statistically significant effect on the nasal retina. No differences in the implicit times of the DC and IC components were observed between SV and EDOF. Compared with the SV, the EDOF lens showed a higher RD in the IC component in the foveal region (p = 0.032). In the remaining retinal areas, the EDOF evoked lower, non-statistically significant RD in both the DC and IC components. The EDOF myopia control CL enhanced the response of the inner layers of the fovea. This might suggest that, besides other mechanisms potentially involved, the central foveal retinal activity might be involved in the mechanism of myopia control with these lenses.