154 research outputs found

    Commodity prices rise sharply at turning points

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    Commodity prices depend on supply and demand. With an uneven distribution of resources, prices are high at locations starved of commodity and low where it is abundant. We introduce an agent-based model in which agents set their prices to maximize profit. At steady state, the market self-organizes into three groups: excess producers, consumers, and balanced agents. When resources are scarce, prices rise sharply at a turning point due to the disappearance of excess producers. Market data of commodities provide evidence of turning points for essential commodities, as well as a yield point for non-essential ones

    Security and Privacy for Modern Wireless Communication Systems

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    The aim of this reprint focuses on the latest protocol research, software/hardware development and implementation, and system architecture design in addressing emerging security and privacy issues for modern wireless communication networks. Relevant topics include, but are not limited to, the following: deep-learning-based security and privacy design; covert communications; information-theoretical foundations for advanced security and privacy techniques; lightweight cryptography for power constrained networks; physical layer key generation; prototypes and testbeds for security and privacy solutions; encryption and decryption algorithm for low-latency constrained networks; security protocols for modern wireless communication networks; network intrusion detection; physical layer design with security consideration; anonymity in data transmission; vulnerabilities in security and privacy in modern wireless communication networks; challenges of security and privacy in node–edge–cloud computation; security and privacy design for low-power wide-area IoT networks; security and privacy design for vehicle networks; security and privacy design for underwater communications networks

    Suicide ideation in older people: a qualitative review and Meta-aggregation of Asian studies

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    AimsTo appraise and synthesize qualitative studies examining older Asian people’s experiences of suicidal ideation.DesignQualitative review and meta-aggregation.Data sourcesFour databases were accessed to retrieve papers published between 1990 and 2022 including the grey literature, hand-searching of reference lists of retrieved papers and key journals. The phenomenon of interest included participants older than 60 years old, must have experienced a form of suicidal ideation and/or an unsuccessful attempt, had actively thought about harming themselves and be of Asian ethnicity.Review methodsThis review was conducted according to Consolidated Criteria for Reporting Qualitative Research and the Joanna Briggs Institute’s System for the Unified Management of the Assessment and Review of Information.ResultsOf the 289 potential studies, seven papers met the inclusion criteria. Two synthesized findings resulted from this review–The Suffering Situation: A Life without Meaning in Older Age and The Healing Situation: A Life Worth Living. The experiences of older Asian people varied from feelings of loneliness, despair and isolation to wanting to live a fruitful life into old age.ConclusionSuicidal ideation in the older person is a growing concern especially with the rise in suicide in this age group. Rising health care costs and erosion of traditional family values means that the older person views themselves as a burden. However, because of the limited number of qualitative studies from an Asian perspective it is difficult to ascertain the full extent of the issues surrounding suicide in older people

    Tetradentate Platinum(II) Emitters: Design Strategies, Photophysics, and OLED Applications

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    This chapter provides an overview of tetradentate platinum(II) emitters as a promising class of metal-organic phosphorescent dopants for organic light-emitting diodes (OLEDs). Tetradentate platinum(II) emitters showing blue, green, and red light emissions, which are essential for full color displays as well as white light emission, are reviewed and discussed in the context of molecular design and photophysical and electroluminescent properties. Emphasis is placed on the molecular structures, the nature of emissive excited states [including ligand-centered (LC), intra-ligand charge transfer (ILCT), metal-to-ligand charge transfer (MLCT), and excimeric and oligomeric metal-metal-to-ligand charge transfer (MMLCT)], the intermolecular interactions impacting photophysical attributes (e.g., emission energies, quantum yields, and decay times), and OLED device performances

    Waning effectiveness against COVID-19-related hospitalisation, severe complications, and mortality with two to three doses of CoronaVac and BNT162b2: a case-control study

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    BACKGROUND: This study aims to evaluate waning effectiveness against severe and fatal COVID-19 with 2-3 doses of CoronaVac/BNT162b2, where data is limited. METHODS: A case-control study included individuals aged ≥18 years, unvaccinated or received 2-3 doses of CoronaVac/BNT162b2, using electronic healthcare databases in Hong Kong. Those with first COVID-19-related hospitalisation, severe complications, or mortality between 1 January and 15 August 2022 were defined as cases and matched with up-to-10 controls by age, sex, index date, and Charlson Comorbidity Index. Vaccine effectiveness (VE) against COVID-19-related outcomes was estimated at different time intervals from second and third dose vaccination (0-13 up-to 210-240 days) using conditional logistic regression adjusted for comorbidities and medications. RESULTS: By 211-240 days after second dose, VE against COVID-19-related hospitalisation reduced to 46.6% (40.7%-51.8%) for BNT162b2 and 36.2% (28.0%-43.4%) for CoronaVac, and VE against COVID-19-related mortality were 73.8% (55.9%-84.4%) and 76.6% (60.8%-86.0%). After third dose, VE against COVID-19-related hospitalisation decreased from 91.2% (89.5%-92.6%) for BNT162b2 and 76.7% (73.7%-79.4%) for CoronaVac at 0-13 days, to 67.1% (60.4%-72.6%) and 51.3% (44.2%-57.5%) at 91-120 days. VE against COVID-19-related mortality for BNT162b2 remained high from 0-13 days [98.2% (95.0%-99.3%)] to 91-120 days [94.6% (77.7%-98.7%)], and for CoronaVac reduced from 0-13 days [96.7% (93.2%-98.4%)] to 91-120 days [86.4% (73.3%-93.1%)]. CONCLUSIONS: Significant risk reduction against COVID-19-related hospitalisation and mortality after CoronaVac or BNT162b2 vaccination was observed for >240 and >120 days after second and third dose compared to unvaccinated, despite significant waning over time. Timely administration of booster doses could provide higher levels of protection

    Effectiveness of BNT162b2 and CoronaVac vaccinations against SARS-CoV-2 omicron infection in people aged 60 years or above: a case–control study

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    BACKGROUND: In view of limited evidence that specifically addresses vaccine effectiveness (VE) in the older population, this study aims to evaluate the real-world effectiveness of BNT162b2 and CoronaVac in older adults during the Omicron BA.2 outbreak. METHODS: This case-control study analyzed data available between January and March 2022 from the electronic health databases in Hong Kong and enrolled individuals aged 60 or above. Each case was matched with up to 10 controls by age, sex, index date and Charlson Comorbidity Index for the four outcomes (COVID-19 infection, COVID-19-related hospitalization, severe complications, and all-cause mortality) independently. Conditional logistic regression was conducted to evaluate VE of BNT162b2 and CoronaVac against COVID-19-related outcomes within 28 days after COVID-19 infection among participants stratified by age groups (60-79, ≥80 years old). RESULTS: A dose-response relationship between the number of vaccine doses received and protection against severe or fatal disease was observed. Highest VE (95% CI) against COVID-19 infection was observed in individuals aged ≥80 who received three doses of BNT162b2 [75.5% (73.1-77.7%)] or three doses of CoronaVac [53.9% (51.0-56.5%)] compared to those in the younger age group who received three doses of BNT162b2 [51.1% (49.9-52.4%)] or three doses of CoronaVac [2.0% (-0.1-4.1%)]. VE (95% CI) was higher for other outcomes, reaching 91.9% (89.4-93.8%) and 86.7% (84.3-88.8%) against COVID-19-related hospitalization; 85.8% (61.2-94.8%) and 89.8% (72.4-96.3%) against COVID-19-related severe complications; and 96.4% (92.9-98.2%) and 95.0% (92.1-96.8%) against COVID-19-related mortality after three doses of BNT162b2 and CoronaVac in older vaccine recipients, respectively. A similar dose-response relationship was established in younger vaccine recipients and after stratification by sex and Charlson Comorbidity Index. CONCLUSION: Both BNT162b2 and CoronaVac vaccination were effective in protecting older adults against COVID-19 infection and COVID-19-related severe outcomes amidst the Omicron BA.2 pandemic, and VE increased further with the third dose

    Association between the risk of seizure and COVID-19 vaccinations: A self-controlled case-series study

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    OBJECTIVE: The risk of seizure following BNT162b2 and CoronaVac vaccinations has been sparsely investigated. This study aimed to evaluate this association. METHOD: Patients who had their first seizure-related hospitalization between February 23, 2021 and January 31, 2022 were identified in Hong Kong. All seizure episodes happening on the day of vaccination (day 0) were excluded since clinicians validated that most of the cases on day 0 were syncopal episodes. Within-individual comparison using a modified self-controlled case series analysis was applied to estimate the incidence rate ratio (IRR) with 95% confidence intervals (CI) of seizure using conditional Poisson regression. RESULTS: We identified 1656 individuals who had their first seizure-related hospitalization (BNT162b2: 426; CoronaVac: 263; unvaccinated: 967) within the observation period. The incidence of seizure was 1.04 (95% CI: 0.80-1.33) and 1.11 (95% CI: 0.80-1.50) per 100,000 doses of BNT162b2 and CoronaVac administered respectively. 16 and 17 individuals received second dose after having first seizure within 28 days after first dose of BNT162b2 and CoronaVac vaccinations, respectively. None had recurrent seizures after the second dose. There was no increased risk during day 1-6 after the first (BNT162b2: IRR=1.39, 95% CI=0.75-2.58; CoronaVac: IRR=1.19, 95% CI=0.50-2.83) and second doses (BNT162b2: IRR=1.36, 95% CI 0.72-2.57; CoronaVac: IRR=0.71, 95% CI=0.22-2.30) of vaccinations. During 7-13, 14-20- and 21-27-days post-vaccination, no association was observed for both vaccines. SIGNIFICANCE: The findings demonstrated no increased risk of seizure following BNT162b2 and CoronaVac vaccinations. Future studies will be warranted to evaluate the risk of seizure following COVID-19 vaccinations in different populations with subsequent doses to ensure the generalizability
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