The short infectious period of COVID-19 indicates the efficiency of fast switching periodic protocols

Abstract The Covid-19 disease pandemic is showing the importance of an accurate quantification of transmissibility in order to design and tune public health responses. Transmissibility is usually quantified in terms of the reproduction number Rt, the average number of secondary cases caused by an infected individual. Here we show the central role also played by w(z), the distribution of generation times z, namely the time between successive infections in a transmission chain. We obtain an accurate estimate of w(z) by means of a novel method which allows us to simultaneously obtain its evaluation together with the measure of Rt, over the course of an epidemic, and the number of exogenous infected cases. We use one year of data from COVID-19 officially reported cases in the 21 Italian regions, since the first confirmed case on February 2020. We find that w(z) is a distribution very peaked around its average value z ≃ 6 days with a standard deviation σ smaller than one day. This estimate of σ is much smaller than previous ones obtained by means of contact tracing from the distribution of serial intervals. We perform extended numerical simulations to demonstrate that, because of the small value of σ, post-lockdown mitigation policies such as fast periodic switching and/or alternating quarantine can be extremely efficient.

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Aether - A Novel Method to Eliminate False Positives in Private Automated Contact Tracing

2020 IEEE Globecom Workshops (GC Wkshps ◽

10.1109/gcwkshps50303.2020.9367390 ◽

2020 ◽

Author(s):

Satvik Dasari

Keyword(s):

False Positives ◽

Contact Tracing ◽

Novel Method

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A Mathematical Model of Contact Tracing during the 2014–2016 West African Ebola Outbreak

Mathematics ◽

10.3390/math9060608 ◽

2021 ◽

Vol 9 (6) ◽

pp. 608

Author(s):

Danielle Burton ◽

Suzanne Lenhart ◽

Christina J. Edholm ◽

Benjamin Levy ◽

Michael L. Washington ◽

...

Keyword(s):

Mathematical Model ◽

Disease Management ◽

Ebola Virus ◽

Virus Disease ◽

Infected Individual ◽

Vital Role ◽

West African ◽

Contact Tracing ◽

The Novel ◽

Using Data

The 2014–2016 West African outbreak of Ebola Virus Disease (EVD) was the largest and most deadly to date. Contact tracing, following up those who may have been infected through contact with an infected individual to prevent secondary spread, plays a vital role in controlling such outbreaks. Our aim in this work was to mechanistically represent the contact tracing process to illustrate potential areas of improvement in managing contact tracing efforts. We also explored the role contact tracing played in eventually ending the outbreak. We present a system of ordinary differential equations to model contact tracing in Sierra Leonne during the outbreak. Using data on cumulative cases and deaths, we estimate most of the parameters in our model. We include the novel features of counting the total number of people being traced and tying this directly to the number of tracers doing this work. Our work highlights the importance of incorporating changing behavior into one’s model as needed when indicated by the data and reported trends. Our results show that a larger contact tracing program would have reduced the death toll of the outbreak. Counting the total number of people being traced and including changes in behavior in our model led to better understanding of disease management.

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Establishment, contagiousness, and initial spread of SARS-CoV-2 in Canada

FACETS ◽

10.1139/facets-2020-0055 ◽

2021 ◽

Vol 6 (1) ◽

pp. 180-194

Author(s):

Martin Krkošek ◽

Madeline Jarvis-Cross ◽

Kiran Wadhawan ◽

Isha Berry ◽

Jean-Paul R. Soucy ◽

...

Keyword(s):

Latent Period ◽

Bayesian Framework ◽

Contact Tracing ◽

Transmission Model ◽

Infectious Period ◽

Median Reduction ◽

Community Transmission

This study empirically quantifies dynamics of SARS-CoV-2 establishment and early spread in Canada. We developed a transmission model that was simulation tested and fitted in a Bayesian framework to timeseries of new cases per day prior to physical distancing interventions. A hierarchical version was fitted to all provinces simultaneously to obtain average estimates for Canada. Across scenarios of a latent period of 2–4 d and an infectious period of 5–9 d, the R0 estimate for Canada ranges from a minimum of 3.0 (95% CI: 2.3–3.9) to a maximum of 5.3 (95% CI: 3.9–7.1). Among provinces, the estimated commencement of community transmission ranged from 3 d before to 50 d after the first reported case and from 2 to 25 d before the first reports of community transmission. Among parameter scenarios and provinces, the median reduction in transmission needed to obtain R0 < 1 ranged from 46% (95% CI: 43%–48%) to 89% (95% CI: 88%–90%). Our results indicate that local epidemics of SARS-CoV-2 in Canada entail high levels of stochasticity, contagiousness, and observation delay, which facilitates rapid undetected spread and requires comprehensive testing and contact tracing for its containment.

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Will You Come Back to Contribute? Investigating the Inactivity of OSS Core Developers in GitHub

10.21203/rs.3.rs-302498/v1 ◽

2021 ◽

Author(s):

Fabio Calefato ◽

Marco Aurelio Gerosa ◽

Giuseppe Iaffaldano ◽

Filippo Lanubile ◽

Igor Fabio Steinmacher

Keyword(s):

Open Source ◽

Open Source Software ◽

State Transition ◽

Active State ◽

State Model ◽

Novel Method ◽

To Come ◽

One Year ◽

The Individual ◽

To Receive

Abstract Several Open-Source Software (OSS) projects depend on the continuity of their development communities to remain sustainable. Understanding how developers become inactive or why they take breaks can help communities prevent abandonment and incentivize developers to come back. In this paper, we propose a novel method to identify developers’ inactive periods by analyzing the individual rhythm of contributions to the projects. Using this method, we quantitatively analyze the inactivity of core developers in 18 OSS organizations hosted on GitHub. We also survey core developers to receive their feedback about the identified breaks and transitions. Our results show that our method was effective for identifying developers’ breaks. About 94% of the surveyed core developers agreed with our state model of inactivity; 71% and 79% of them acknowledged their breaks and state transition, respectively. We also show that all core developers take breaks (at least once) and about a half of them (~ 45%) have completely disengaged from a project for at least one year. We also analyzed the probability of transitions to/from inactivity and found that developers who pause their activity have a ~ 35 to ~ 55% chance to return to an active state; yet, if the break lasts for a year or longer, then the probability of resuming activities drops to ~ 21–26%, with a ~ 54% chance of complete disengagement. These results may support the creation of policies and mechanisms to make OSS community managers aware of breaks and potential project abandonment.

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A renewal equation model to assess roles and limitations of contact tracing for disease outbreak control

Royal Society Open Science ◽

10.1098/rsos.202091 ◽

2021 ◽

Vol 8 (4) ◽

Author(s):

Francesca Scarabel ◽

Lorenzo Pellis ◽

Nicholas H. Ogden ◽

Jianhong Wu

Keyword(s):

Deterministic Model ◽

Infected Individual ◽

Equation Model ◽

Renewal Equation ◽

Contact Tracing ◽

Calendar Time ◽

Individual Level ◽

Total Incidence ◽

Community Transmission ◽

The Individual

We propose a deterministic model capturing essential features of contact tracing as part of public health non-pharmaceutical interventions to mitigate an outbreak of an infectious disease. By incorporating a mechanistic formulation of the processes at the individual level, we obtain an integral equation (delayed in calendar time and advanced in time since infection) for the probability that an infected individual is detected and isolated at any point in time. This is then coupled with a renewal equation for the total incidence to form a closed system describing the transmission dynamics involving contact tracing. We define and calculate basic and effective reproduction numbers in terms of pathogen characteristics and contact tracing implementation constraints. When applied to the case of SARS-CoV-2, our results show that only combinations of diagnosis of symptomatic infections and contact tracing that are almost perfect in terms of speed and coverage can attain control, unless additional measures to reduce overall community transmission are in place. Under constraints on the testing or tracing capacity, a temporary interruption of contact tracing may, depending on the overall growth rate and prevalence of the infection, lead to an irreversible loss of control even when the epidemic was previously contained.

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Distance Based Pattern Driven Mining for Outlier Detection in High Dimensional Big Dataset

ACM Transactions on Management Information Systems ◽

10.1145/3469891 ◽

2022 ◽

Vol 13 (1) ◽

pp. 1-17

Author(s):

Ankit Kumar ◽

Abhishek Kumar ◽

Ali Kashif Bashir ◽

Mamoon Rashid ◽

V. D. Ambeth Kumar ◽

...

Keyword(s):

Data Mining ◽

Comparative Analysis ◽

Outlier Detection ◽

Credit Card ◽

High Dimensional ◽

Work Efficiency ◽

Average Value ◽

Novel Method ◽

Detection Of Outliers ◽

Better Than

Detection of outliers or anomalies is one of the vital issues in pattern-driven data mining. Outlier detection detects the inconsistent behavior of individual objects. It is an important sector in the data mining field with several different applications such as detecting credit card fraud, hacking discovery and discovering criminal activities. It is necessary to develop tools used to uncover the critical information established in the extensive data. This paper investigated a novel method for detecting cluster outliers in a multidimensional dataset, capable of identifying the clusters and outliers for datasets containing noise. The proposed method can detect the groups and outliers left by the clustering process, like instant irregular sets of clusters (C) and outliers (O), to boost the results. The results obtained after applying the algorithm to the dataset improved in terms of several parameters. For the comparative analysis, the accurate average value and the recall value parameters are computed. The accurate average value is 74.05% of the existing COID algorithm, and our proposed algorithm has 77.21%. The average recall value is 81.19% and 89.51% of the existing and proposed algorithm, which shows that the proposed work efficiency is better than the existing COID algorithm.

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The Characteristic of Viewpoint’s Time-Transients in Traffic Operation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.2937 ◽

2013 ◽

Vol 671-674 ◽

pp. 2937-2940

Author(s):

Hui Zhi Xu ◽

Hong Bo Li ◽

Yun Zhang

Keyword(s):

Parameter Estimation ◽

View Point ◽

Average Value ◽

Novel Method ◽

Traffic Operation ◽

Time Point

A novel method based on the characteristic of view point time and transients was presented on the data collected by iView X HED. It adopted snow and non-snow road as vehicle circumstance, and acquired the time and transients of driver’s view-points. An experiment was introduced at the key time point in the traffic to analyze the regulations of time and transients. The results provided the average value of view point time and transient, the parameter estimation in the condition of ice-snow road is longer than that in non-snow road.

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Incidence of surgical-site infections in orthopaedic surgery: a northern Italian experience

Epidemiology and Infection ◽

10.1017/s0950268810001627 ◽

2010 ◽

Vol 139 (5) ◽

pp. 777-782 ◽

Cited By ~ 6

Author(s):

A. CASTELLA ◽

P. A. ARGENTERO ◽

E. C. FARINA ◽

L. CHARRIER ◽

E. M. BRACH DEL PREVER ◽

...

Keyword(s):

Surgical Site Infections ◽

Public Hospitals ◽

Surveillance Systems ◽

Knee Prostheses ◽

Surveillance Period ◽

Italian Experience ◽

Italian Regions ◽

Post Operation ◽

One Year

SUMMARYA prospective cohort study with a 1-year telephone follow-up was performed to estimate the incidence of surgical-site infections (SSIs) in hip and knee prostheses. Twenty-five public hospitals equipped with orthopaedic units in two Italian regions were involved. An 8-month surveillance period was set to obtain significant data at a regional level and data were collected by the infection control nurses of each centre. One-year follow-up was completed in 75% of cases. SSIs were recorded in 45 cases (incidence rate 1·9/100 person-years, 95% CI 1·4–2·5). Thirty-six percent of SSIs were diagnosed during hospitalization and 95·3% within 90 days post-operation. This incidence is similar to that reported by European and USA surveillance systems. The proposed investigative method proved to be reliable and feasible. A prolonged surveillance for at least 3 months post-operation yields a good estimate of SSI in joint replacements.

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Observation on dominance of swells over wind-seas in the coastal waters of Gulf of Mannar, India

10.5194/os-2017-16 ◽

2017 ◽

Author(s):

M. M. Amrutha ◽

V. Sanil Kumar

Keyword(s):

Wave Height ◽

Coastal Waters ◽

Indian Subcontinent ◽

Sea Breeze ◽

Early Morning ◽

Gulf Of Mannar ◽

Study Region ◽

Average Value ◽

Late Evening ◽

One Year

Abstract. In coastal gulfs generally, predominance of wind-seas are expected. Waves measured at a location having a water depth of 15 m in the nearshore waters of Gulf of Mannar during one year period (1 May 2015 to 30 April 2016) is used to examine the predominance of wind-seas and swells through spectral characterization. The study shows that even though the location is in a gulf, the annual average value (~ 0.84 m) of the significant wave height at this area is comparable to that along the coastal waters of the Indian subcontinent, but the annual maximum value (~ 1.7 m) recorded is much less than that (3 to 5 m) observed in those regions. Also, large seasonal variations are not observed in the wave height. The waves of the study region are under the control of sea-breeze with the maximum in the late evening hours and the minimum in the early morning hours. 53 % of the surface height variance in the study area is a result of southeast and south swells and the remaining are the east and southeast wind-seas.

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