Outbreaks of SARS-CoV-2 are threatening the health care systems of several countries around the world. The initial control of SARS-CoV-2 epidemics relied on non-pharmaceutical interventions, such as ...social distancing, teleworking, mouth masks and contact tracing. However, as pre-symptomatic transmission remains an important driver of the epidemic, contact tracing efforts struggle to fully control SARS-CoV-2 epidemics. Therefore, in this work, we investigate to what extent the use of universal testing, i.e., an approach in which we screen the entire population, can be utilized to mitigate this epidemic. To this end, we rely on PCR test pooling of individuals that belong to the same households, to allow for a universal testing procedure that is feasible with the limited testing capacity. We evaluate two isolation strategies: on the one hand pool isolation, where we isolate all individuals that belong to a positive PCR test pool, and on the other hand individual isolation, where we determine which of the individuals that belong to the positive PCR pool are positive, through an additional testing step. We evaluate this universal testing approach in the STRIDE individual-based epidemiological model in the context of the Belgian COVID-19 epidemic. As the organisation of universal testing will be challenging, we discuss the different aspects related to sample extraction and PCR testing, to demonstrate the feasibility of universal testing when a decentralized testing approach is used. We show through simulation, that weekly universal testing is able to control the epidemic, even when many of the contact reductions are relieved. Finally, our model shows that the use of universal testing in combination with stringent contact reductions could be considered as a strategy to eradicate the virus.
On 11 March 2020, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19) a pandemic
. The strategies based on non-pharmaceutical interventions that were used to contain the ...outbreak in China appear to be effective
, but quantitative research is still needed to assess the efficacy of non-pharmaceutical interventions and their timings
. Here, using epidemiological data on COVID-19 and anonymized data on human movement
, we develop a modelling framework that uses daily travel networks to simulate different outbreak and intervention scenarios across China. We estimate that there were a total of 114,325 cases of COVID-19 (interquartile range 76,776-164,576) in mainland China as of 29 February 2020. Without non-pharmaceutical interventions, we predict that the number of cases would have been 67-fold higher (interquartile range 44-94-fold) by 29 February 2020, and we find that the effectiveness of different interventions varied. We estimate that early detection and isolation of cases prevented more infections than did travel restrictions and contact reductions, but that a combination of non-pharmaceutical interventions achieved the strongest and most rapid effect. According to our model, the lifting of travel restrictions from 17 February 2020 does not lead to an increase in cases across China if social distancing interventions can be maintained, even at a limited level of an on average 25% reduction in contact between individuals that continues until late April. These findings improve our understanding of the effects of non-pharmaceutical interventions on COVID-19, and will inform response efforts across the world.
Recent research in cybersecurity has begun to develop active defense strategies using game‐theoretic optimization of the allocation of limited defenses combined with deceptive signaling. These ...algorithms assume rational human behavior. However, human behavior in an online game designed to simulate an insider attack scenario shows that humans, playing the role of attackers, attack far more often than predicted under perfect rationality. We describe an instance‐based learning cognitive model, built in ACT‐R, that accurately predicts human performance and biases in the game. To improve defenses, we propose an adaptive method of signaling that uses the cognitive model to trace an individual's experience in real time. We discuss the results and implications of this adaptive signaling method for personalized defense.
Efficient long‐term cell tracing in a noninvasive and real‐time manner is of great importance to understand genesis, development, invasion, and metastasis of cancerous cells. Cell penetrating organic ...dots with aggregation‐ induced emission (AIE) characteristics are successfully developed as long‐term cell trackers. The AIE dots enjoy the advantages of high emission efficiency, large Stokes shift, good biocompatibility, and high photostability, which ensure their good performance in long‐term non‐invasive in vitro cell tracing. Moreover, it is the first report that AIE dots exhibit certain permeability to cellular nucleus, making them attractive potential candidates for nucleus imaging. The AIE dots display superior performance compared to their counterparts of inorganic quantum dots, opening a new avenue in the development of fluorescent probes for monitoring biological processes.
Encapsulation of orange‐red fluorescent luminogens with aggregation‐induced emission (AIE) characteristics in biocompatible matrix yields AIE dots with strong emission, large Stokes shift, good biocompatibility, and high photostability. Application of the AIE dots for in vitro cell tracing and nucleus imaging has been demonstrated using MCF‐7 breast cancer cells as an example.
Low infection and case-fatality rates have been thus far observed in Taiwan. One of the reasons for this major success is better use of big data analytics in efficient contact tracing and management ...and surveillance of those who require quarantine and isolation.
We present here a unique application of big data analytics among Taiwanese people who had contact with more than 3000 passengers that disembarked at Keelung harbor in Taiwan for a 1-day tour on January 31, 2020, 5 days before the outbreak of coronavirus disease (COVID-19) on the Diamond Princess cruise ship on February 5, 2020, after an index case was identified on January 20, 2020.
The smart contact tracing-based mobile sensor data, cross-validated by other big sensor surveillance data, were analyzed by the mobile geopositioning method and rapid analysis to identify 627,386 potential contact-persons. Information on self-monitoring and self-quarantine was provided via SMS, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tests were offered for symptomatic contacts. National Health Insurance claims big data were linked, to follow-up on the outcome related to COVID-19 among those who were hospitalized due to pneumonia and advised to undergo screening for SARS-CoV-2.
As of February 29, a total of 67 contacts who were tested by reverse transcription-polymerase chain reaction were all negative and no confirmed COVID-19 cases were found. Less cases of respiratory syndrome and pneumonia were found after the follow-up of the contact population compared with the general population until March 10, 2020.
Big data analytics with smart contact tracing, automated alert messaging for self-restriction, and follow-up of the outcome related to COVID-19 using health insurance data could curtail the resources required for conventional epidemiological contact tracing.
The nature of the COVID-19 pandemic may require governments to use privacy-encroaching technologies to help contain its spread. One technology involves co-location tracking through mobile Wi-Fi, GPS, ...and Bluetooth to permit health agencies to monitor people's contact with each other, thereby triggering targeted social-distancing when a person turns out to be infected. The effectiveness of tracking relies on the willingness of the population to support such privacy encroaching measures. We report the results of two large surveys in the United Kingdom, conducted during the peak of the pandemic, that probe people's attitudes towards various tracking technologies. The results show that by and large there is widespread acceptance for co-location tracking. Acceptance increases when the measures are explicitly time-limited and come with opt-out clauses or other assurances of privacy. Another possible future technology to control the pandemic involves "immunity passports", which could be issued to people who carry antibodies for the COVID-19 virus, potentially implying that they are immune and therefore unable to spread the virus to other people. Immunity passports have been considered as a potential future step to manage the pandemic. We probe people's attitudes towards immunity passports and find considerable support overall, although around 20% of the public strongly oppose passports.
The continued proliferation of information technology in all aspects of our lives fosters benefits but also generates risks to individuals' privacy. In emerging contexts, such as government ...surveillance technologies, there is a dearth of research investigating the positive and negative drivers of citizens' acceptance. This is an important gap given the importance of citizen acceptance to the success of these technologies and the need to balance potentially wide-reaching benefits with any dilution of citizen privacy. We conduct a longitudinal examination of the competing influences of positive beliefs and privacy concerns on citizens' acceptance of a COVID-19 national contact tracing mobile application among 405 Irish citizens. Combining privacy calculus theory with social exchange theory, we find that citizens’ initial acceptance is shaped by their perceptions of health benefits and social influence, with reciprocity exhibiting a sustained influence on acceptance over time and privacy concerns demonstrating a negative, albeit weak influence on willingness to rely on the application. The study offers important empirical and theoretical implications for the privacy literature in the government surveillance, location-based services, and mobile health application contexts, as well as practical implications for governments and developers introducing applications that rely on mass acceptance and reciprocal information disclosure.
•Contact tracing applications offer both benefits and risks to individuals' privacy.•Perceived health benefits influence willingness to download and rely on these apps.•Social influence is an important factor in acceptance of contact tracing apps.•Reciprocity shapes acceptance of contact tracing apps prior to and post launch.
In this study, a 15N tracing incubation experiment and an in situ monitoring study were combined to investigate the effects of different N fertilizer regimes on the mechanisms of soil N dynamics from ...a long-term repeated N application experiment. The field study was initiated in 2003 under a wheat-maize rotation system in the subtropical rain-fed purple soil region of China. The experiment included six fertilization treatments applied on an equivalent N basis (280 kg N ha−1), except for the residue only treatment which received 112 kg N ha−1: (1) UC, unfertilized control; (2) NPK, mineral fertilizer NPK; (3) OM, pig manure; (4) OM-NPK, pig manure (40% of applied N) with mineral NPK (60% of applied N); (5) RSD, crop straw; (6) RSD-NPK, crop straw (40% of applied N) with mineral NPK (60% of applied N). The results showed that long-term repeated applications of mineral or organic N fertilizer significantly stimulated soil gross N mineralization rates, which was associated with enhanced soil C and N contents following the application of N fertilizer. The crop N offtake and yield were positively correlated with gross mineralization. Gross autotrophic nitrification rates were enhanced by approximately 2.5-fold in the NPK, OM, OM-NPK, and RSD-NPK treatments, and to a lesser extent by RSD application, compared to the UC. A significant positive relationship between gross nitrification rates and cumulative N loss via interflow and runoff indicated that the mechanisms responsible for increasing N loss following long-term applications of N fertilizer were governed by the nitrification dynamics. Organic fertilizers stimulated gross ammonium (NH4+) immobilization rates and caused a strong competition with nitrifiers for NH4+, thus preventing a build-up of nitrate (NO3−). Overall, in this study, we found that partial or complete substitution of NPK fertilizers with organic fertilizers can reduce N losses and maintain high crop production, except for the treatment involving application of RSD alone. Therefore, based on the N transformation dynamics observed in this study, organic fertilizers in combination with mineral fertilizer applications (i.e. OM, OM-NPK, and RSD-NPK treatments) are recommended for crop production in the subtropical rain-fed purple soils in China.
•N supply via mineralization was found to be important in controlling plant growth.•The mechanisms responsible for N loss were governed by nitrification dynamics.•Substituting organic fertilizers for NPK can reduce N losses and maintain crop yields.•Several fertilization strategies were recommended for the purple soil region of China.
•Contact tracing as an extreme case of the privacy paradox: which values?•Present benefits: freedom of movement, not morally responsible.•Future risks: privacy, habituation to security policies and ...health.•In crisis situations, contact tracing apps contribute to self-disciplining.•French government plays on the paradox and downplays long term concerns.
Contact tracing apps are presented as a solution, if not the solution, to curb pandemics in the Covid-19 crisis. In France, despite heated public institutional debate on privacy related issues, the app was presented by government as an essential benefit for protecting health and lives, thus avoiding both politicians and citizens to feel morally responsible and looking guilty, and as essential to recover our freedom to move. However we argue that, while detection of cases have still not been reported after 10 days and one million app downloads - a situation comparable to Australia who launched its app a month before -, the adoption of the app generates important risks to our informational privacy, surveillance and habituation to security policies. It also may create discrimination, distrust and generate other health problems such as addiction and others as 5G technology continues to be deployed without prior impact studies. Finally the smartphone app against covid epidemics appears as an extreme case of the privacy paradox where the government plays on the immediate benefits and downplays long-term concerns while inducing a technology of self. Contact tracing apps may become an emblematic case for digital transformation and value changes in the western world.
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