Search Results (331)

Surface soil moisture (SM) is a critical factor in hydrological modeling, agricultural management, and numerical weather forecasting. This paper presents a highly effective soil moisture retrieval algorithm developed for the FY-3E (FengYun-3E) GNOS-R (GNSS Occultation Sounder II-Reflectometry) instrument. The algorithm incorporates a first-order vegetation model that considers vegetation density and volume scattering. Utilizing multi-angle GNOS-R observations, the algorithm derives surface reflectivity, which is combined with ancillary data on opacity, vegetation water content, and soil moisture from SMAP (Soil Moisture Active Passive) to optimize the retrieval process. The algorithm has been specifically tailored for different surface conditions, including bare soil, areas with low vegetation, and densely vegetated regions. The algorithm directly incorporates the angle-dependence of observations, leading to enhanced retrieval accuracy. Additionally, a new approach parameterizes surface roughness as a function of angle, allowing for refined corrections in reflectivity measurements. For vegetated areas, the algorithm effectively isolates the soil surface signal by eliminating volume scattering and vegetation effects, enabling the accurate estimation of soil moisture. By leveraging multi-angle data, the algorithm achieves significantly improved retrieval accuracy, with root mean square errors of 0.0235, 0.0264, and 0.0191 (g/cm³) for bare, low-vegetation, and dense-vegetation areas, respectively. This innovative methodology offers robust global soil moisture estimation capabilities using the GNOS-R instrument, surpassing the accuracy of previous techniques. Full article

Background: Lipedema is a chronic disease of subcutaneous adipose tissue that predominantly affects women and is frequently associated with endocrinopathies such as insulin resistance and obesity. Its pathogenesis is still unclear, and treatment, which requires a multi-disciplinary approach, is prolonged over time and is not always effective. There is currently no drug treatment available for this disease. Methods: Five different cases of women with lipedema and insulin resistance, treated with Glucagon-Like Peptide-1 Receptor Agonists (GLP-1 RAs) and once-weekly exenatide, in association or not with lifestyle changes (diet or physical activity) for 3 to 6 months are described. Changes in anthropometric parameters, symptoms, clinical findings and the thickness of superficial adipose tissue measured by ultrasound were evaluated. Results: Treatment with exenatide, whether combined with a change in diet or physical activity, resulted in a reduction in the characteristic symptoms of lipedema, in pain evoked by pinching the adipose tissue fold and in the thickness of subcutaneous adipose tissue at the levels of the lower limbs, abdomen and upper limbs. In four out of five cases, a reduction in body weight was observed, particularly during the first three months of treatment and in cases with greater metabolic impairment. Clinical, instrumental and subjective improvements were also observed in cases where there was no reduction in body weight and in patients who had previously undergone lower limb liposuction. Conclusions: The improvement in symptoms and clinical signs of lipedema, in addition to the reduction in adipose tissue in patients with lipedema and insulin resistance with exenatide, suggests a novel pharmacological approach to the disease, which can be combined with other conservative and surgical treatments to promote weight reduction. These results also highlight the association of this disease with metabolic alterations and the fundamental role of an accurate diagnosis followed by the treatment of comorbidities and excess weight in these patients. Full article

The purpose of this paper is to analyze the multi-wavelength and multi-instrument observations of two quiescent filament eruptions as well as the deflection of associated CMEs from the radial direction. The events occurred on 18 October 2017 and 9 May 2021, respectively, in the southern solar hemisphere. Both of them and associated flares were registered by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO) and the Solar Terrestrial Relations Observatory–Ahead (STEREO A) Observatory in different EUV wavebands. Using data from STEREO A COR1 and COR2 instruments and the Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO), we investigated morphology and kinematics of the eruptions and the latitudinal offset of the related CMEs with respect to the erupting filaments. Our observations provide the evidence that the two filament eruptions were highly non-radial. The observed deviations are attributed to the presence of low-latitude coronal holes. Full article

The forestry sector is increasingly dealing with a significant lack of labor and faces the difficult task of securing a professional, stable and sustainable manpower. In this study, different strategic directions for strengthening forestry workforce sustainability are presented and evaluated. The considered strategic directions were developed with respect to forestry employees’ views on necessary measures for making the forestry occupation more appealing. Those measures were observed in three categories: (I) stronger recruiting, (II) stronger retention and (III) higher work commitment. The findings of the survey and other performed analyses resulted in the creation of four different strategic directions: (1) the direct financial strategy, implying increased direct monetary compensation as the main instrument and putting focus on labor productivity; (2) the indirect financial strategy, stressing worker wellbeing through indirect material benefits and aiming at performance quality; (3) the educational strategy, focusing on worker training and education and (4) the technical–technological strategy, aiming at the increased utilization of modern machinery and advanced technologies in forest operations. The results of the study include a comparison of the defined strategies by SWOT analysis and the construction of An analytic Hierarchy Process (AHP) model as the multi-criteria tool for strategy evaluation. Considering the possibility and conditions of its implementation in the national forestry sector, the technical–technological strategy has been evaluated as best option to pursue. The objective of the study is to contribute to enhancing the sustainability of forestry workforce by defining critical issues and pointing to specific cornerstones that can assist in formulating effective future policies and strategies in the forestry sector. Full article

This paper demonstrates that perfectly calibrating a multi-asset model to observed market prices of all basket call options is insufficient to uniquely determine the price of a best-of call option. Previous research on multi-asset option pricing has primarily focused on complete market settings or assumed specific parametric models, leaving fundamental questions about model risk and pricing uniqueness in incomplete markets inadequately addressed. This limitation has critical practical implications: derivatives practitioners who hedge best-of options using basket-equivalent instruments face fundamental distributional uncertainty that compounds the well-recognized non-linearity challenges. We establish this non-uniqueness using convex analysis (extreme ray characterization demonstrating geometric incompatibility between payoff structures), measure theory (explicit construction of distinct equivalent probability measures), and geometric analysis (payoff structure comparison). Specifically, we prove that the set of equivalent probability measures consistent with observed basket prices contains distinct measures yielding different best-of option prices, with explicit no-arbitrage bounds $[a_K,b_K]$ quantifying this uncertainty. Our theoretical contribution provides the first rigorous mathematical foundation for several empirically observed market phenomena: wide bid-ask spreads on extremal options, practitioners’ preference for over-hedging strategies, and substantial model reserves for exotic derivatives. We demonstrate through concrete examples that substantial model risk persists even with perfect basket calibration and equivalent measure constraints. For risk-neutral pricing applications, equivalent martingale measure constraints can be imposed using optimal transport theory, though this requires additional mathematical complexity via Schrödinger bridge techniques while preserving our fundamental non-uniqueness results. The findings establish that additional market instruments beyond basket options are mathematically necessary for robust exotic derivative pricing. Full article

Multi-component interventions have been demonstrated to be an effective method for the prevention of frailty. Nevertheless, they have not yet been widely adopted in practice due to considerable resource and labor demands associated with their administration. To overcome the limitations, this study aimed to determine the feasibility of unsupervised intervention based on digital therapy. A mobile application has been developed to deliver multi-component exercise coaching to frail older adults. A total of 30 participants (with a mean age of 72.10 ± 4.54 years) were recruited from two community centers and used the mobile application for 12 weeks without supervision. Prior to utilizing the mobile application, each participant received an initial education. Outcomes of the Short Physical Performance Battery (SPPB), the Korean version of the Fatigue, Resistance, Ambulation, Illnesses, and Loss of weight (K-FRAIL) scale, activities of daily living (ADL), instrumental activities of daily living (IADL), self-efficacy, and depression, were evaluated before and after using the mobile application. Significant improvements in the mean SPPB score (9.6 ± 1.7 to 11.7 ± 0.5) and depression (3.23 ± 3.08 to 2.00 ± 2.11) were observed. The total adherence rate of all participants was 86.1%. No statistically significant differences were observed in the remaining outcomes. These findings suggest that the unsupervised intervention could be a viable option for older adults. Full article

Background/Objectives: The COVID-19 pandemic presented unprecedented challenges to healthcare systems worldwide, significantly impacting individuals with chronic conditions who depend on continuous medical care. In Romania, the pandemic revealed systemic vulnerabilities, particularly in ensuring access to services for older adults and rural populations. This study aimed to assess perceived barriers to healthcare access and service quality among Romanian patients with chronic diseases and a confirmed history of COVID-19, within the framework of the country’s multi-tiered healthcare system. Methods: A cross-sectional study was conducted between January and March 2025, involving 16 adult participants diagnosed with at least one chronic illness. Data were collected using a 30-item questionnaire administered by the principal investigator after obtaining informed consent. The instrument explored access to services, challenges related to remote consultations, and satisfaction with nursing care. Descriptive and comparative analyses were carried out based on age group and area of residence. Due to the small sample size, the results are considered exploratory and context-specific. Results: Most participants reported disrupted access to healthcare services, especially within public sector facilities. Rural residents experienced longer delays in receiving care than those in urban areas. Digital health tools were perceived as barriers by 75% of respondents aged 60 and above, while younger participants adapted more easily. Overall satisfaction with nursing care was moderate to high (mean score: 3.56/5), with the highest ratings observed among patients aged 30–60 years. Conclusions: This study highlights significant barriers to healthcare access among Romanian patients with chronic illnesses and a confirmed COVID-19 diagnosis during the pandemic. The key challenges included digital exclusion and rural–urban disparities. The findings underscore the need for targeted strategies to enhance digital health literacy, adapt care delivery models, and strengthen healthcare system resilience in future public health emergencies. Full article

In this paper, we present a novel passive dual-tuned magnetic metasurface, which can enhance the field distribution produced by a closely placed radio-frequency coil for both ¹H and ²³Na 1.5 T MRI imaging. In particular, the proposed solution comprises a 5 × 5 capacitively loaded array, in which each unit-cell is composed of two concentric spiral coils. Specifically, the unit-cell internal spiral coil operates at the proton Larmor frequency (64 MHz), whereas the external is at the sodium one (17 MHz). Therefore, the paper aims to demonstrate the possibility of enhancing the magnetic field distribution in transmission and reception for 1.5 T MRI scanners by using the same metasurface configuration for imaging both nuclei, thus drastically simplifying the required instrumentation. We first describe the theoretical model used to design and synthetize the dual-tuned magnetic metasurface. Next, full-wave simulations are carried out to validate the approach. Finally, we report the experimental results acquired by testing the fabricated prototype at the workbench, observing a good agreement with the theoretical design and the numerical simulations. In particular, the metasurface increases the transmission efficiency T_x in presence of a biological phantom by a factor 3.5 at 17 MHz and by a factor 5 at 64 MHz, respectively. The proposed solution can pave the way for MRI multi-nuclei diagnostic technique with better images quality, simultaneously reducing the scanning time, the invasiveness on the patient and the overall costs. Full article

Using a multi-analytical approach, this investigation characterized Parmigiano Reggiano PDO cheese produced with milk from dairy cows fed different diets. Ten samples of Parmigiano Reggiano PDO cheese, aged for 24 months, were produced with milk from dairy cows fed only dry hay (P-DH; N = 6) or a diet with part of the dry hay replaced with fresh herbage (P-FF; N = 4). Instrumental (Flash GC-FID) analysis of the volatile fraction, image analyses, and sensory quantitative descriptive analysis (QDA^®) were carried out. The Parmigiano Reggiano cheese belonging to the P-FF group showed a higher intensity of yellow than P-DH for both sensory and image analyses. Regarding the volatile profiles, no differences were observed related to the two experimental groups, while sensory analyses allowed for some discrimination, in particular color and aroma attributes. Instrumental and sensory characterization can be used to obtain a unique analytical profile for Parmigiano Reggiano PDO cheeses produced with milk from dairy cows fed different forage sources and help to define the quality and authenticity of this typical high-value food product. Full article

Multi-messenger astronomy and time-domain astronomy are strongly linked even if they do not have the same objectives. Multi-messenger astronomy is an astrophysical observation approach born by the simultaneous, even if casual, detection of a few events discovered up to now. In contrast, time-domain astronomy is a recent technological trend that aims to make observations to explore the sky not with imaging, astrometry, photometry or spectroscopy but through the fast dynamic behavior of celestial objects. Time-domain astronomy aims to detect events on a temporal scale between seconds and nanoseconds. In this paper, a time-domain infrared fast detector for ground-based telescopes is proposed. This instrument can be useful for multi-messenger observations, and it is able to detect fast astronomical signals in the order of 1 ns. It is based on HgCdTe photoconductors, but the InAsSb photovoltaic detector has also been tested. The detection system designed to detect fast mid-infrared bursts includes trigger modules, an off-line noise-canceling strategy, and a classifier of the transients. Classification is derived from the analysis of fast instabilities in particle circular accelerators. This paper aims to be a preliminary feasibility study. Full article

Implied by the terminologies “Harang Reversal” and “Harang Discontinuity”, there are two significant features of the Harang region: (i) the reversal of auroral electrojets along with the underlying plasma convection flow and electric (E) fields, and (ii) the discontinuity between the electrojets/convection flows/E-fields. Even the earliest studies reported the discontinuity observed in the meridional E-field. Conversely, some of the previous studies state that convection flow and E-field reversals do not involve any physical discontinuity. We investigate these two features (i–ii) observed in five topside-ionosphere Harang scenarios. Each scenario occurred during a sequence of events that led to the onset of the substorm expansion phase, when the Harang region was newly formed. Our results show (1) the newly formed Harang region between the dusk and dawn convection cells, where one convection cell wraps around the other, (2) the zonal drift- and E-field reversals, (3) the discontinuity between the dusk and dawn convection flows and also between the reversing E-field components, and (4) the Earthward electromagnetic energy deposition locally minimizing or diminishing within the discontinuity and peaking within the reversing zonal drift and E-fields. Thus, the observed convection flow and E-field reversals involved the development of discontinuity. Full article

The multi-band atmospheric correction algorithms, now referred to as remote sensing reflectance (R_rs) algorithms, have been implemented on a NASA computing facility for global remote sensing of ocean color and atmospheric aerosol parameters from data acquired with several satellite instruments, including the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi spacecraft platform. These algorithms are based on the 2-band version of the SeaWiFS (Sea-Viewing Wide Field-of-View Sensor) algorithm. The bands centered near 0.75 and 0.865 μm are used for atmospheric corrections. In order to obtain high-quality R_rs values over Case 1 waters (deep clear ocean waters), strict masking criteria are implemented inside these algorithms to mask out thin clouds and very turbid water pixels. As a result, R_rs values are often not retrieved over bright Case 2 waters. Through our analysis of VIIRS data, we have found that spatial features of bright Case 2 waters are observed in VIIRS visible band images contaminated by thin cirrus clouds. In this article, we describe methods of combining cirrus and aerosol corrections to improve spatial coverage in R_rs retrievals over Case 2 waters. One method is to remove cirrus cloud effects using our previously developed operational VIIRS cirrus reflectance algorithm and then to perform atmospheric corrections with our updated version of the spectrum-matching algorithm, which uses shortwave IR (SWIR) bands above 1 μm for retrieving atmospheric aerosol parameters and extrapolates the aerosol parameters to the visible region to retrieve water-leaving reflectances of VIIRS visible bands. Another method is to remove the cirrus effect first and then make empirical atmospheric and sun glint corrections for water-leaving reflectance retrievals. The two methods produce comparable retrieved results, but the second method is about 20 times faster than the spectrum-matching method. We compare our retrieved results with those obtained from the NASA VIIRS R_rs algorithm. We will show that the assumption of zero water-leaving reflectance for the VIIRS band centered at 0.75 μm (M6) over Case 2 waters with the NASA R_rs algorithm can sometimes result in slight underestimates of water-leaving reflectances of visible bands over Case 2 waters, where the M6 band water-leaving reflectances are actually not equal to zero. We will also show conclusively that the assumption of thin cirrus clouds as ‘white’ aerosols during atmospheric correction processes results in overestimates of aerosol optical thicknesses and underestimates of aerosol Ångström coefficients. Full article

This work presents a comprehensive investigation of tropospheric NO₂ measurements using a portable ground-based Pandora spectrometer, incorporating an independently designed and implemented calibration and retrieval process (P-CAR v1.0). We designed and optimized a region-specific algorithm for retrieving tropospheric NO₂ column densities in China. The measurement process began with establishing a spectral calibration system for processing the Pandora’s raw observations, followed by enhancing the differential optical absorption spectroscopy (DOAS) algorithm to retrieve both the slant column densities (SCDs) and tropospheric vertical column densities (VCDs) of NO₂. To validate our retrieval products, comparative analyses were conducted against co-located MAX-DOAS measurements. The results demonstrate excellent agreement between Pandora-retrieved tropospheric NO₂ and MAX-DOAS observations, with correlation coefficients exceeding 0.96 for both hourly and daily mean VCDs and fitting slopes greater than 0.90. Furthermore, the validation extended to multi-satellite observations from the Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI), exhibiting pronounced consistency, as evidenced by the correlation coefficients all surpassing 0.90 for the hourly mean values. These findings confirm the high accuracy and reliability of NO₂ retrievals from the portable Pandora instrument, significantly boosting its potential for atmospheric monitoring and application. Full article

About ten years ago, we established the first coronagraph that has been continuously operating on the high plateau of western China. This coronagraph is an internal occulting, 10 cm aperture instrument, installed at Lijiang Station through a collaboration with the Norikura Station of the National Astronomical Observatory of Japan. To ensure high efficiency in current and future coronal observations, developing integrated observation systems is essential for reliable, autonomous, and remote operation of coronagraphs. This paper introduces an advanced integrated observation and control system, based on the Lijiang 10 cm coronagraph. The coronagraph focuses on the observations for the solar inner corona, capturing the coronal green-line emission within a field range from $1.03R_{⨀}$ to $2.5R_{⨀}$. To enhance the observational precision and efficiency, a comprehensive integrated system has been designed, incorporating various subsystems, including precise pointing and tracking mechanisms, a multi-band filter system, a protective dome system, and a robust data storage infrastructure. This paper details the hardware architecture and software frameworks supporting each subsystem. Results from extended operational testing confirm the stability of the system, its capacity for autonomous and remote observations, and significant improvements in the automation and efficiency of coronal imaging. The automated observation system will be further improved and used for our future coronagraphs to be developed for coronal magnetism diagnosis. Full article

The following study presents the results obtained from a comparative analysis of dry (powder and hard snow) and wet snow based on satellite data and in situ data methods for monitoring in the high mountain belt of Bulgaria. The aim of the study is to analyze the effectiveness of different spectral indices based on satellite data from Synthetic Aperture Radar (SAR), high-resolution (HR) imagery, and spectrometer data for assessing the state and dynamics of the snow cover. The methods studied and the results obtained were validated by instrument-based field observations, with instruments using thermal imaging cameras, spectrometer measurements, ground control points, and HR imagery. Satellite data offer an ever-widening view of trends in snow distribution over time. All these data combined provide a detailed picture of surface temperature and snow properties, which are crucial for understanding snowmelt processes and the energy balance in the high-altitude belt. The findings suggest that a multi-method approach, utilizing the combined advantages of SAR satellite data, offers the most comprehensive and accurate framework for satellite-based snow cover monitoring in the high mountain regions of Bulgaria, such as Rila Mountain. This integrative strategy not only improves the precision of snow cover estimates but can also support many water resource-related studies, such as snowmelt runoff studies, snow avalanche modeling, and better-informed decisions in the management and maintenance of winter tourism resorts. Full article