scholarly journals Dynamic Network Strategies for SARS-CoV-2 Control on a Cruise Ship

2020 ◽  
Author(s):  
Samuel M. Jenness ◽  
Kathryn S. Willebrand ◽  
Amyn A. Malik ◽  
Benjamin A. Lopman ◽  
Saad B. Omer
Keyword(s):  
Clinical Response ◽  
Large Scale ◽  
Leisure Activities ◽  
Dynamic Network ◽  
Optimal Strategies ◽  
Transmission Model ◽  
Contact Network ◽  
Prevention Measures ◽  
Contact Networks ◽  
Before And After

ABSTRACTSARS-CoV-2 outbreaks have occurred on several nautical vessels, driven by the high-density contact networks on these ships. Optimal strategies for prevention and control that account for realistic contact networks are needed. We developed a network-based transmission model for SARS-CoV-2 on the Diamond Princess outbreak to characterize transmission dynamics and to estimate the epidemiological impact of outbreak control and prevention measures. This model represented the dynamic multi-layer network structure of passenger-passenger, passenger-crew, and crew-crew contacts, both before and after the large-scale network lockdown imposed on the ship in response to the disease outbreak. Model scenarios evaluated variations in the timing of the network lockdown, reduction in contact intensity within the sub-networks, and diagnosis-based case isolation on outbreak prevention. We found that only extreme restrictions in contact patterns during network lockdown and idealistic clinical response scenarios could avert a major COVID-19 outbreak. Contact network changes associated with adequate outbreak prevention were the restriction of passengers to their cabins, with limited passenger-crew contacts. Clinical response strategies required for outbreak prevention included early mass screening with an ideal PCR test (100% sensitivity) and immediate case isolation upon diagnosis. Public health restrictions on optional leisure activities like these should be considered until longer-term effective solutions such as a COVID-19 vaccine become widely available.

scholarly journals Superspreading k-cores at the center of COVID-19 pandemic persistence

2020 ◽  
Author(s):  
Matteo Serafino ◽  
Higor S. Monteiro ◽  
Shaojun Luo ◽  
Saulo D. S. Reis ◽  
Carles Igual ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Large Scale ◽  
Mobile Apps ◽  
Human Mobility ◽  
Contact Tracing ◽  
Weak Links ◽  
Contact Network ◽  
Transmission Network ◽  
Before And After ◽  
High Betweenness

The spread of COVID-19 caused by the recently discovered SARS-CoV-2 virus has become a worldwide problem with devastating consequences. To slow down the spread of the pandemic, mass quarantines have been implemented globally, provoking further social and economic disruptions. Here, we address this problem by implementing a large-scale contact tracing network analysis to find the optimal quarantine protocol to dismantle the chain of transmission of coronavirus with minimal disruptions to society. We track billions of anonymized GPS human mobility datapoints from a compilation of hundreds of mobile apps deployed in Latin America to monitor the evolution of the contact network of disease transmission before and after the confinements. As a consequence of the lockdowns, people's mobility across the region decreases by ~53%, which results in a drastic disintegration of the transmission network by ~90%. However, this disintegration did not halt the spreading of the disease. Our analysis indicates that superspreading k-core structures persist in the transmission network to prolong the pandemic. Once the k-cores are identified, the optimal strategy to break the chain of transmission is to quarantine a minimal number of 'weak links' with high betweenness centrality connecting the large k-cores. Our results demonstrate the effectiveness of an optimal tracing strategy to halt the pandemic. As countries race to build and deploy contact tracing apps, our results could turn into a valuable resource to help deploy protocols with minimized disruptions.

scholarly journals Augmenting contact matrices with time-use data for fine-grained intervention modelling of disease dynamics: A modelling analysis

2021 ◽  
pp. 096228022110370
Author(s):  
Edwin van Leeuwen ◽  
Frank Sandmann ◽  
Keyword(s):  
Public Health ◽  
Time Use ◽  
Large Scale ◽  
Leisure Activities ◽  
Public Health Intervention ◽  
Social Contact ◽  
Daily Activities ◽  
Transmission Model ◽  
Fine Grained ◽  
The Impact

Social distancing is an important public health intervention to reduce or interrupt the sustained community transmission of emerging infectious pathogens, such as severe acute respiratory syndrome-coronavirus-2 during the coronavirus disease 2019 pandemic. Contact matrices are typically used when evaluating such public health interventions to account for the heterogeneity in social mixing of individuals, but the surveys used to obtain the number of contacts often lack detailed information on the time individuals spend on daily activities. The present work addresses this problem by combining the large-scale empirical data of a social contact survey and a time-use survey to estimate contact matrices by age group (0--15, 16--24, 25–44, 45–64, 65+ years) and daily activity (work, schooling, transportation, and four leisure activities: social visits, bar/cafe/restaurant visits, park visits, and non-essential shopping). This augmentation allows exploring the impact of fewer contacts when individuals reduce the time they spend on selected daily activities as well as when lifting such restrictions again. For illustration, the derived matrices were then applied to an age-structured dynamic-transmission model of coronavirus disease 2019. Findings show how contact matrices can be successfully augmented with time-use data to inform the relative reductions in contacts by activity, which allows for more fine-grained mixing patterns and infectious disease modelling.

scholarly journals A Cognitive Model of the «Spread of Drug Abuse»

2019 ◽  
Vol 13 (4) ◽  
pp. 535-546
Author(s):  
Alexander Sukhodolov ◽  
Valentina Marenko ◽  
Anna Bychkova
Keyword(s):  
Drug Abuse ◽  
Cognitive Modeling ◽  
Large Scale ◽  
Leisure Activities ◽  
Cognitive Model ◽  
Cognitive Structure ◽  
Cognitive Map ◽  
Prevention Measures ◽  
Contributing Factors ◽  
Systemic Feature

The authors examined the problem of the spread of drug abuse and describe a research procedure based on the method of cognitive modeling. To achieve this, the authors formulated the problems that are solved through cognitive mode­ling, which includes the following stages: outlining the problem field, building a cognitive map in the form of an orgraph, coordinating expert evaluations of the mutual impact of various factors, working out expert rules based on the cause-and-effect speculations, and conducting an imitation experiment. The first stage of cognitive modeling included an overview of research publications on the problem, which allowed the authors to identify the set of contributing factors. Stages of cognitive mo­deling were used to build a cognitive model «The spread of drug abuse» with such influencing factors as «the condition of the dwelling and utilities sphere», «professional occupation», «degree of the society’s criminalization», «organization of leisure activities and cultural work for the population», «prevention measures». The target factor was «the spread of drug abuse». The adequacy of the developed cognitive structure was verified by the systemic feature of «sensitivity» in the imitation experiment that recreates some semblance of reality in laboratory conditions. Analytical procedures were used to determine the expert evaluations of the mutual impact of factors and to work out expert rules. A cognitive map was developed in the form of a weighed orgraph, which was viewed as the framework of the problem where it was possible to observe the changes in the overall holistic situation by influencing its various points. The imitation experiment was conducted using Microsoft Excel, and its results agree with the logics of speculations. It is stated that although the simplified cognitive map includes five factors that influence the problem, increasing their number to build a more large-scale version of the cognitive model will contribute to deeper and more comprehensive research of the problem. The presented model is a promising area for the application of modern methods of researching the spread of drug abuse and spread of crimes in the sphere illegal drug trade with the use of Big Data technology.

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

scholarly journals THU0642-HPR EVOLUTION OF THE PERCEPTIONS OF RA PATIENTS AFTER EDUCATION PATIENT SESSION TEACHING METHOTREXATE SELF-INJECTION A PROSPECTIVE PILOT STUDY

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 566.1-566
Author(s):  
S. Afilal ◽  
H. Rkain ◽  
B. Berchane ◽  
J. Moulay Berkchi ◽  
S. Fellous ◽  
...  
Keyword(s):  
Pilot Study ◽  
Patient Education ◽  
Median Duration ◽  
Large Scale ◽  
Education Session ◽  
Prospective Pilot Study ◽  
Mean Delay ◽  
Lack Of Information ◽  
Level Of Satisfaction ◽  
Before And After

Background:Methotrexate is a gold standard for treatment of RA. In our context, RA patients prefer to be injected by paramedics rather than self-injecting. This can be explained by patients’ bad perceptions of self-injection or lack of information. Appropriate self-injection education can therefore be an important element in overcoming these obstacles and improving disease self-management.Objectives:Compare the RA patients’ perceptions on methotrexate self-injection before and after a patient education session.Methods:Prospective pilot study that included 27 consecutive patients (81.5% female, mean age 44.4 years, illiteracy rate 40.7%) with RA (median duration of progression of 4 years, mean delay in referral for specialist of 6 months, median duration of methotrexate use of 1 year). The patients benefited from an individual patient education session to learn how to self-inject with methotrexate subcutaneously. The patient education session was supervised by a nurse and a rheumatologist with a control a week later. Perceptions of the reluctance to self-inject and the difficulties encountered by patients were assessed before the patient education session, after the 1st and 2nd self-injection of methotrexate using a 10 mm visual analog scale. Patients also reported their level of satisfaction (10 mm VAS) after the 1st and 2nd self-injection.Results:The mean duration of patient education session is 13 min.Table I compares the evolution of the degrees of reluctance to self-injection, the difficulties encountered, and the satisfaction experienced by the patients.Table 1.Evolution of RA patients’ perceptions on the methotrexate self-injection. (N = 27)BeforeAfter the 1stself-injectionAfter the 2end self-injectionpVAS reluctance (0-10mm)6,5 ± 3,62,2 ± 2,91,0 ± 2,3<0,0001VAS difficulty (0-10mm)7,5 ± 2,62,5 ± 2,71,0 ± 1,9<0,0001VAS satisfaction (0-10mm)-8,9 ± 1,89,5 ± 1,50,002Conclusion:This study suggests the effectiveness of a methotrexate self-injection patient education session in RA patients. It also highlights the value of patient education in rheumatologic care. A large-scale study is necessary to better interpret and complete these preliminary results from this pilot study.Disclosure of Interests:None declared

scholarly journals Dynamic variations in salinity and potassium grade of a potassium-rich brine deposit in Lop Nor basin, China

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lichun Ma ◽  
Kai Wang ◽  
Yu Zhang ◽  
Qingfeng Tang ◽  
Hui Yan
Keyword(s):  
Large Scale ◽  
Sustainable Use ◽  
Potassium Sulfate ◽  
Middle Pleistocene ◽  
Underground Brine ◽  
Average Decrease ◽  
Rational Development ◽  
Mining History ◽  
Before And After ◽  
Lop Nor

AbstractThe Quaternary Lop Nor playa is the largest production base of potassium sulfate in the world. It has a mining history of more than 10 years, and its share in the Chinese potassium sulfate market is about 50% to-date. In this basin, the high-salinity potassium-rich brines are mainly contained in Middle Pleistocene–Holocene glauberite strata. Based on the monitoring of the underground brine table and geochemical analysis, this study reveals variations in the underground brine table and potassium-bearing grade before and after large-scale mining in the Lop Nor potash deposit. The results showed that the underground brine table and potassium sulfate grade decreased by varying degrees over sub-mineral areas after large-scale mining. The underground brine table declined by 8.5 m, on average, in the Luobei depression, by 6.4 m in the Tenglong platform and by 1.9 m in the Xinqing platform. However, the potassium-bearing grade showed the different trend. The Tenglong platform had the largest decline with average decreases in layers W1, W2 and W3 of 18.2%, 13.0% and 24.8%, respectively. In the Xinqing platform, the average decrease in layersW2 and W3 were 17.4% and 16.0% respectively. The Luobei depression decreases were relatively small (W1, W2 and W3 decreased 4.3%, 4.2% and 3.1%, respectively). This research provides a theoretical basis for the rational development and sustainable use of the potassium-rich brines in the Lop Nor basin.

scholarly journals Species and characteristics of volatile organic compounds emitted from an auto-repair painting workshop

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Y. Song ◽  
H. Chun
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Large Scale ◽  
Butyl Acetate ◽  
Small Scale ◽  
Indoor Environments ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Before And After ◽  
Adsorption Systems

AbstractVolatile organic compounds (VOCs) are secondary pollutant precursors having adverse impacts on the environment and human health. Although VOC emissions, their sources, and impacts have been investigated, the focus has been on large-scale industrial sources or indoor environments; studies on relatively small-scale enterprises (e.g., auto-repair workshops) are lacking. Here, we performed field VOC measurements for an auto-repair painting facility in Korea and analyzed the characteristics of VOCs emitted from the main painting workshop (top coat). The total VOC concentration was 5069–8058 ppb, and 24–35 species were detected. The VOCs were mainly identified as butyl acetate, toluene, ethylbenzene, and xylene compounds. VOC characteristics differed depending on the paint type. Butyl acetate had the highest concentration in both water- and oil-based paints; however, its concentration and proportion were higher in the former (3256 ppb, 65.5%) than in the latter (2449 ppb, 31.1%). Comparing VOC concentration before and after passing through adsorption systems, concentrations of most VOCs were lower at the outlets than the inlets of the adsorption systems, but were found to be high at the outlets in some workshops. These results provide a theoretical basis for developing effective VOC control systems and managing VOC emissions from auto-repair painting workshops.

scholarly journals Universal Masking to Control Healthcare-Associated Transmission of SARS-CoV-2

2021 ◽  
pp. 1-24
Author(s):  
Eliza R. Thompson ◽  
Faith S. Williams ◽  
Pat A. Giacin ◽  
Shay Drummond ◽  
Eric Brown ◽  
...  
Keyword(s):  
Large Scale ◽  
Infection Prevention ◽  
Index Patient ◽  
Field Investigation ◽  
Point Prevalence ◽  
Control Measures ◽  
Prevention Measures ◽  
Infection Control Measures ◽  
Va Health Care System ◽  
Healthcare Associated

Abstract Objective: To assess extent of a healthcare-associated outbreak of SARS-CoV-2 and evaluate effectiveness of infection control measures, including universal masking Design: Outbreak investigation including 4 large-scale point-prevalence surveys Setting: Integrated VA Health Care System with 2 facilities and 330 beds Participants: Index patient and 250 exposed patients and staff Methods: We identified exposed patients and staff and classified them as probable and confirmed cases based on symptoms and testing. We performed a field investigation and assessment of patient and staff interactions to develop probable transmission routes. Infection prevention interventions implemented included droplet and contact precautions, employee quarantine, and universal masking with medical and cloth facemasks. Four point-prevalence surveys of patient and staff subsets were conducted using real-time reverse-transcriptase polymerase chain reaction for SARS-CoV-2. Results: Among 250 potentially exposed patients and staff, 14 confirmed cases of Covid-19 were identified. Patient roommates and staff with prolonged patient contact were most likely to be infected. The last potential date of transmission from staff to patient was day 22, the day universal masking was implemented. Subsequent point-prevalence surveys in 126 patients and 234 staff identified 0 patient cases and 5 staff cases of Covid-19, without evidence of healthcare-associated transmission. Conclusions: Universal masking with medical facemasks was effective in preventing further spread of SARS-CoV-2 in our facility in conjunction with other traditional infection prevention measures.

scholarly journals Correcting for experiment-specific variability in expression compendia can remove underlying signals

GigaScience ◽  
2020 ◽  
Vol 9 (11) ◽  
Author(s):  
Alexandra J Lee ◽  
YoSon Park ◽  
Georgia Doing ◽  
Deborah A Hogan ◽  
Casey S Greene
Keyword(s):  
Gene Expression ◽  
Large Scale ◽  
Original Signal ◽  
Batch Effects ◽  
Technical Variability ◽  
The Past ◽  
Statistical Correction ◽  
Before And After ◽  
Data Collections ◽  
Biological Patterns

Abstract Motivation In the past two decades, scientists in different laboratories have assayed gene expression from millions of samples. These experiments can be combined into compendia and analyzed collectively to extract novel biological patterns. Technical variability, or "batch effects," may result from combining samples collected and processed at different times and in different settings. Such variability may distort our ability to extract true underlying biological patterns. As more integrative analysis methods arise and data collections get bigger, we must determine how technical variability affects our ability to detect desired patterns when many experiments are combined. Objective We sought to determine the extent to which an underlying signal was masked by technical variability by simulating compendia comprising data aggregated across multiple experiments. Method We developed a generative multi-layer neural network to simulate compendia of gene expression experiments from large-scale microbial and human datasets. We compared simulated compendia before and after introducing varying numbers of sources of undesired variability. Results The signal from a baseline compendium was obscured when the number of added sources of variability was small. Applying statistical correction methods rescued the underlying signal in these cases. However, as the number of sources of variability increased, it became easier to detect the original signal even without correction. In fact, statistical correction reduced our power to detect the underlying signal. Conclusion When combining a modest number of experiments, it is best to correct for experiment-specific noise. However, when many experiments are combined, statistical correction reduces our ability to extract underlying patterns.

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