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COVID-19 transmission within a family cluster by presymptomatic carriers in China
Get PDFWe report a COVID-19 family cluster caused by a presymptomatic case. There were 9 family members, including 8 laboratory-confirmed with COVID-19, and a 6-year-old child had no evidence of infection. Amongst the 8 patients, one adult and one 13-month-old infant were asymptomatic, one adult was diagnosed as having severe pneumonia
Early findings from a large-scale user study of CHESTNUT: Validations and implications
Get PDFTowards a serendipitous recommender system with user-centred understanding, we have built CHESTNUT , an Information Theory-based Movie Recommender System, which introduced a more comprehensive understanding of the concept. Although off-line evaluations have already demonstrated that CHESTNUT has greatly improved serendip-ity performance, feedback on CHESTNUT from real-world users through online services are still unclear now. In order to evaluate how serendip-itous results could be delivered by CHESTNUT , we consequently designed , organized and conducted large-scale user study, which involved 104 participants from 10 campuses in 3 countries. Our preliminary feedback has shown that, compared with mainstream collaborative filtering techniques, though CHESTNUT limited users' feelings of unex-pectedness to some extent, it showed significant improvement in their feelings about certain metrics being both beneficial and interesting, which substantially increased users' experience of serendipity. Based on them, we have summarized three key takeaways, which would be beneficial for further designs and engineering of serendipitous recommender systems, from our perspective. All details of our large-scale user study could be found at https://github.com/unnc-idl-ucc/Early-Lessons-From-CHESTNU
Distributional analysis of rural-urban household healthcare expenditure differentials in developing countries: evidence from Ghana
Get PDFEquity in access to and use of healthcare resources is a global development agenda. Policy makers’ knowledge of the sources of differences in household healthcare spending is crucial for effective policy. This paper investigates the differences in the determinants of household healthcare expenditure across space and along selected quantiles of healthcare expenditure in Ghana. The determinants of rural-urban healthcare expenditure gap are also explored. Data was obtained from the sixth round of the Ghana Living Standards Survey (GLSS 6) conducted in 2013. An unconditional quantile regression (UQR) and a decomposition technique based on UQR, adjusted for sample selection bias, were applied. Findings indicate that differences in the determinants of household healthcare expenditure across space and along quantiles are driven by individual-level variables. Besides, the rural-urban health expenditure gap is greatest among households in the lower quantiles and this gap is largely driven by differences in household income per capita and percentage of household members enrolled on health insurance policies. To reduce rural-urban healthcare expenditure inequality, targeted policies should be prioritised in addition to efforts to narrow rural-urban differences in household per capita income and enrolment in health insurance policies
Collective pharmaceutical procurement in China may have unintended consequences in supply and pricing
Get PDFThe collective pharmaceutical procurement was launched in China in 2018 to reduce the prices of
selected drugs, by pooling the demands of member cities and granting the contract to the manufacturer with the lowest bid. We found the procurement significantly decreased the prices of most
drugs. We also identified significant price increases on some drugs, indicating that manufacturers of these
drugs may have strong market power to manipulate prices. The “winner-takes-all” principle applied in
the procurement may further increase the market power of winning manufacturers by expanding their
respective market shares. They may take the advantage of the market power to increase drug prices in the
long-run. The continuously lowering price-caps may force the losing bidders to exit the market. A careful assessment of the unintended consequences of the collective procurement is warranted
Transition delay and drag reduction using biomimetically inspired surface waves
Get PDFThis paper explores the use of Two-Dimensional sinusoidal surface features to delay transition and/or reduce drag. The authors, in this paper demonstrated that the presence of low amplitude sinusoidal surface features might damp the disturbances in the laminar boundary layer, reduce wall shear stress and maintain laminar flow for longer than a conventional flat plate. The hypothesis of the paper is inspired by the simplification of the dermal denticle on the surface of the shark-skin. Simulations are carried out using the Transition SST model in FLUENT based on the evidences of the transition model being suitable for a wider variety of high curvature scenarios. The surface waves are simulated for different amplitudes and wavelengths and their impact on transition onset and drag reduction are quantified at different velocities. Results presented in this paper indicate that a transition delay of 10.8% and a drag reduction of 5.2% are achievable. Furthermore, this paper adds credence to the notion that biomimicry is a very promising avenue for future drag reducing methods
Challenges in urban stormwater management in Chinese cities: A hydrologic perspective
Get PDFFor managing the worsening urban water disasters in China, the Government of China proposed the concept of “Sponge City” in 2013 and initiated the strategy in 30 pilot cities from 2015. Despite the promise of the concept, there have been many challenges in implementing the “Sponge City” program (SCP). In this manuscript, we discuss the hydrology-related challenges in implementing the SCP. In particular, we consider two key challenges: (1) Determination of the “Volume Capture Ratio of Annual Rainfall” (VCRAR), as controlling urban stormwater runoff is one of the core targets of the SCP; and (2) Estimation of a proper rainfall threshold, which influences the layout of green-infrastructures in the SCP to achieve the core VCRAR target. To discuss these challenges, we consider the city of Beijing, the capital of China, as a case study. Our analysis shows that the trade-offs between the investment for the SCP and its potential economic benefits should be considered by undertaking a proper determination of VCRAR. The VCRAR estimated for Beijing from the present analysis is 0.73. This value is more reasonable than the empirical value of 0.80 that is presently used, as it can guarantee the positive rate of return on the investment. We also find that the nonstationary characteristics of rainfall data and their spatiotemporal differences are important for the estimation of the rainfall threshold in SCP. For instance, even using the daily rainfall data over a period of 30 years (1983–2012) in Beijing, as required by the National Assessment Standard, the estimated rainfall threshold of 27.3 mm underestimates the reasonable rainfall threshold that should at least be larger than 30.0 mm. Thus, the former cannot ensure the VCRAR target of 0.80. Based on these results, we offer proper approaches and key suggestions towards useful guidelines for delivering better SCP in the Chinese cities
Analysis of the relationship between scintillation parameters, multipath and ROTI
Get PDFGlobal Navigation Satellite System (GNSS) operation can be affected by several environmental factors, of which ionospheric scintillation is one of the most significant. Scintillation is usually characterized by two indices, namely the amplitude scintillation index (S4) and phase scintillation index (σφ). However, these two indices can only be generated by specialized GNSS receivers, which are not widely available all around the world. To popularize the study of scintillation, this article proposes to use more accessible parameters, namely multipath (MP) and rate of change of total electron content index (ROTI), to characterize scintillation. Using GPS data obtained on six days in total from three stations, namely PRU2 and SAO0P located in Sao Paulo, Brazil and SNA0P located in Antarctica, respectively, both the time series plots and 2D maps were generated to investigate the relationship of scintillation indices (S4 and σφ) with MP and ROTI. To prevent the effect of the real multipath error, a 30-degree satellite elevation mask is applied to all the data. As the scintillation indices S4 and σφ have a sampling interval of 1 min, MP and ROTI are calculated with the same sampling interval for a more direct comparison. The results show that the structural similarity (SSIM) and correlation coefficient (CC) between parameters was greater than 0.7 for 70% of outputs. In addition, the variogram and cross-variogram are applied to investigate the spatial structure of the MP, ROTI, S4 and σφ in order to support the results of SSIM and CC. With outputs in three forms, promising spatial and temporal relationships between parameters was observed
Weaving healthy behaviors into new technology routines: Designing in (and for) the COVID-19 work-from-home period
Get PDFSitting in front of computers has become a major part of our workaday routines, challenging us in maintaining active and healthy lifestyles. This challenge becomes even more salient during this worldwide work-from-home period due to COVID-19. While a wide variety of existing interactive systems have been developed to facilitate health tracking and healthy exercises, relatively little research concerns incorporating healthy behaviors as HCI elements. To maximize pervasive health benefits in users’ technology routines, this workshop sets out to explore a design paradigm that enables users to use lightweight, healthy behaviors to perform daily interactions with computing systems. To navigate this new design space, this workshop calls for interdisciplinary endeavors, synergizing expertise from HCI design, health informatics, persuasive technology, exertion game, and psychology
Thermophysical characteristics and application of metallic-oxide based mono and hybrid nanocomposite phase change materials for thermal management systems
Get PDFThis experimental study covers the chemical, physical, thermal characterization and application of novel nanocomposite phase change materials (NCPCMs) dispersed by TiO2, Al2O3, and CuO nanoparticles for thermal management systems. A commercial-grade of paraffin, namely RT-35HC, was considered as a phase change material (PCM). The mono and hybrid NCPCMs were synthesized at a constant weight concentration of 1.0 wt.. In the first phase, various characterization techniques were used to explore the thermophysical properties and chemical interaction of mono and hybrid NCPCMs. In the second phase, the thermal cooling performance was investigated by filling the prepared NCPCMs in a heat sink at various input power levels. The results showed the uniform dispersion of TiO2, Al2O3, and CuO nanoparticles onto the surface of both mono and hybrid NCPCMs without altering the chemical structure of RT-35HC. The optimum latent-heat of fusion and highest thermal conductivity of 228.46 J/g and 0.328 W/m K were obtained, respectively, of Al2OCuO dispersed hybrid NCPCM compared to pure RT-35HC. In comparison of RT-35HC, the increasing trend in specific heat capacity was observed of NCPCMs and 36.47% enhancement was obtained for hybrid NCPCM in solid-phase. The reduction in heat sink base temperature was achieved of 3.67%, 6.13%, 13.95% and 8.23% for NCPCM, NCPCM, NCPCM and NCPCM, respectively, compared to RT-35HC. Further, no phase segregation, less subcooling, smaller phase transition temperature, higher chemical and thermal stability were observed with hybrid NCPCMs which can be used potentially for thermal management of electronic devices, Li-ion batteries and photovoltaic (PV) modules systems
Swash zone morphodynamic modelling including sediment entrained by bore-generated turbulence
Get PDFIn this paper we introduce a mathematical model of sediment entrainment due to bore-generated turbulence in a shallow water context. In this model, the entrainment is assumed to be proportional to the energy decay rate across a bore on a mobile bed. The energy decay rate across a bore on a mobile bed is derived analytically. This model is incorporated into the one dimensional morphodynamic model developed by Zhu and Dodd (2015), which includes bed- and suspended load transport. This results in new shock conditions, which allow for sediment entrainment at a shock. With it we investigate the effects of sediment entrainment due to bore-generated turbulence on beachface evolution under a single swash event driven by a solitary wave. The simulation results imply that sediment entrainment by bore turbulence at the incoming bore dominates over sediment mobilisation by bed shear stress. In contrast, the backwash bore is dominated by bed shear stress related processes. The morphodynamic impact of bore turbulence on this swash event is primarily erosion of the sea bed seaward of the initial shoreline. Any sediment remaining in the water column seaward of this point is then available to be transported by subsequent events. It is shown that the bed step is primarily a bed load related feature, with sediment entrained as suspended load counteracting the bed step growth
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