Assimilation of SMAP products for improving streamflow simulations over tropical climate region — is spatial information more important than temporal information?

Streamflow is one of the key variables in the hydrological cycle. Simulation and forecasting of streamflow are challenging tasks for hydrologists, especially in sparsely gauged areas. Coarse spatial resolution remote sensing soil moisture products (equal to or larger than 9 km) are often assimilated into hydrological models to improve streamflow simulation in large catchments. This study uses the Ensemble Kalman Filter (EnKF) technique to assimilate SMAP soil moisture products at the coarse spatial resolution of 9 km (SMAP 9 km), and downscaled SMAP soil moisture product at the higher spatial resolution of 1 km (SMAP 1 km), into the Soil and Water Assessment Tool (SWAT) to investigate the usefulness of different spatial and temporal resolutions of remotely sensed soil moisture products in streamflow simulation and forecasting. The experiment was set up for eight catchments across the tropical climate of Vietnam, with varying catchment areas from 267 to 6430 km2 during the period 2017–2019. We comprehensively evaluated the EnKF-based SWAT model in simulating streamflow at low, average, and high flow. Our results indicated that high-spatial resolution of downscaled SMAP 1 km is more beneficial in the data assimilation framework in aiding the accuracy of streamflow simulation, as compared to that of SMAP 9 km, especially for the small catchments. Our analysis on the impact of observation resolution also indicates that the improvement in the streamflow simulation with data assimilation is more significant at catchments where downscaled SMAP 1 km has fewer missing observations. This study is helpful for adding more understanding of performances of soil moisture data assimilation based hydrological modelling over the tropical climate region, and exhibits the potential use of remote sensing data assimilation in hydrology

Optimal User Pairing Approach for NOMA-based Cell-free Massive MIMO Systems

This study investigates a non-orthogonal multiple access (NOMA)-assisted cell-free massive multiple-input multiple-output (MIMO) system, considering the impact of both individual and linear-combination channel estimations. To make the best use of NOMA as an enabler for cell-free massive MIMO systems, user pairing should be employed effectively. Random user pairing naturally leads to a non-optimal solution, whereas an exhaustive search approach is unfavorable for practical systems owing to the high complexity. In this study, we propose an optimal user pairing strategy to group users that jointly optimize the minimum downlink rate per user and power allocation at an acceptable cost of complexity. To address this problem, we first relax the binary variables to continuous variables and then develop an iterative algorithm based on the inner approximation method, yielding at least one locally optimal solution. Numerical results show that the proposed user pairing algorithm outperforms existing counterparts, such as conventional beamforming, random pairing, far pairing, and close-pairing strategies, while it can be performed dynamically, that is, two arbitrary users satisfying the formulated problem can be paired regardless of geographical distance. Finally, our approach demonstrates that the combination channel estimation-based NOMA-assisted cell-free massive MIMO achieves the best result in terms of the downlink rate per user when associated with the proposed algorithm

Prototyping of DSSDs for Particle Tracking and Spectroscopy within the EXL Project at Fair

Prototype double-sided silicon strip detectors (DSSD$s$) of 300 $\mu$m thickness produced at PTI St. Petersburg (Russia) were tested for the use as position sensitive, $\Delta E$ and E detectors for tracking and particle identification in the EXL (EXotic nuclei studied in Light-ion induced reactions at the NESR storage ring) setup at the FAIR (Facility for Antiproton and Ion Research) project at GSI. We describe the characteristics of detectors with $16 \times 16,\;64\times 64$ and $64\times 16$ strips, respectively. The response of these detectors for $^{241}$Am $\alpha$ particles injected either from the p or n side was examined. The test measurements were performed partially at GSI and the University of Edinburgh. A first in-beam test with a proton beam of 50 MeV with the latter two DSSDs and two 6.5 mm thick Si(Li) detectors was also done at KVI Groningen, the Netherlands. The results reveal good spectroscopic properties of these detectors

Sustaining effective COVID-19 control in Malaysia through large-scale vaccination

Introduction: As of 3rd June 2021, Malaysia is experiencing a resurgence of COVID-19 cases. In response, the federal government has implemented various non-pharmaceutical interventions (NPIs) under a series of Movement Control Orders and, more recently, a vaccination campaign to regain epidemic control. In this study, we assessed the potential for the vaccination campaign to control the epidemic in Malaysia and four high-burden regions of interest, under various public health response scenarios. Methods: A modified susceptible-exposed-infectious-recovered compartmental model was developed that included two sequential incubation and infectious periods, with stratification by clinical state. The model was further stratified by age and incorporated population mobility to capture NPIs and micro-distancing (behaviour changes not captured through population mobility). Emerging variants of concern (VoC) were included as an additional strain competing with the existing wild-type strain. Several scenarios that included different vaccination strategies (i.e. vaccines that reduce disease severity and/or prevent infection, vaccination coverage) and mobility restrictions were implemented. Results: The national model and the regional models all fit well to notification data but underestimated ICU occupancy and deaths in recent weeks, which may be attributable to increased severity of VoC or saturation of case detection. However, the true case detection proportion showed wide credible intervals, highlighting incomplete understanding of the true epidemic size. The scenario projections suggested that under current vaccination rates complete relaxation of all NPIs would trigger a major epidemic. The results emphasise the importance of micro-distancing, maintaining mobility restrictions during vaccination roll-out and accelerating the pace of vaccination for future control. Malaysia is particularly susceptible to a major COVID-19 resurgence resulting from its limited population immunity due to the country's historical success in maintaining control throughout much of 2020

Impact of perception and assessment of consumers on willingness to pay for upgraded fresh pork: An experimental study in Vietnam

Traditional pork shops play an essential role in delivering pork, the most popular food in Vietnam, to consumers. Studies have shown the need for investment in training and equipment to improve the safety of pork sold at traditional shops. However, it remains unclear how consumers perceived improvement to the hygiene in pork shops and if they are ready to pay premium prices for safer products. This study used an experimental approach to determine consumers' perception and assessment of improved pork shops and their willingness to pay (WTP) for pork products. A total of 152 respondents in two provinces in Vietnam joined in a Becker–DeGroot–Marschak (BDM) mechanism experiment to collect data on WTP for pork from typical and upgraded pork shops. A questionnaire was used to record consumers' perceptions and assessments of the pork shops and products. Overall, consumers were willing to pay 20% more for upgraded fresh pork than for what is currently available on the market. Consumers trusted in the effectiveness of the upgraded intervention and the quality of pork at the pork shop, which increased their WTP for the upgraded pork. Concerns about contaminated pork had a negative impact on the WTP for typical pork, while the high frequency of pork consumption and the existence of elderly family members led to higher WTP for both products. The findings indicate the potential economic benefit of upgrading pork shops, which would be an important driver to motivate sellers to improve food safety