scholarly journals Green Simulation of Pandemic Disease Propagation

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 580
Author(s):  
Spencer Wilson ◽  
Abdullah Alabdulkarim ◽  
David Goldsman
Keyword(s):  
Disease Transmission ◽  
Variance Reduction ◽  
Baseline Scenario ◽  
Green Method ◽  
Common Random Numbers ◽  
Disease Propagation ◽  
Monte Carlo Experiments ◽  
Speed Up ◽  
The Common ◽  
Multiple Scenarios

This paper is concerned with the efficient stochastic simulation of multiple scenarios of an infectious disease as it propagates through a population. In particular, we propose a simple “green” method to speed up the simulation of disease transmission as we vary the probability of infection of the disease from scenario to scenario. After running a baseline scenario, we incrementally increase the probability of infection, and use the common random numbers variance reduction technique to avoid re-simulating certain events in the new scenario that would not otherwise have changed from the previous scenario. A set of Monte Carlo experiments illustrates the effectiveness of the procedure. We also propose various extensions of the method, including its use to estimate the sensitivity of propagation characteristics in response to small changes in the infection probability.

Comparing stochastic systems using regenerative simulation with common random numbers

1979 ◽  
Vol 11 (04) ◽  
pp. 804-819 ◽  
Author(s):  
Philip Heidelberger ◽  
Donald L. Iglehart
Keyword(s):  
Stochastic Models ◽  
Stochastic System ◽  
Variance Reduction ◽  
Stochastic Systems ◽  
Sufficient Conditions ◽  
Random Numbers ◽  
Numerical Examples ◽  
Common Random Numbers ◽  
Regenerative Simulation ◽  
Alternative Designs

Suppose two alternative designs for a stochastic system are to be compared. These two systems can be simulated independently or dependently. This paper presents a method for comparing two regenerative stochastic processes in a dependent fashion using common random numbers. A set of sufficient conditions is given that guarantees that the dependent simulations will produce a variance reduction over independent simulations. Numerical examples for a variety of simple stochastic models are included which illustrate the variance reduction achieved.

Mathematical Model to Assess the Relative Effectiveness of Rift Valley Fever Countermeasures

2013 ◽  
pp. 67-82
Author(s):  
Holly Gaff ◽  
Colleen Burgess ◽  
Jacqueline Jackson ◽  
Tianchan Niu ◽  
Yiannis Papelis ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Relative Effectiveness ◽  
Equation Model ◽  
Valley Fever ◽  
Disease Propagation ◽  
Livestock Population ◽  
Transmission Parameters ◽  
Viral Infectious Disease

Mathematical modeling of infectious diseases is increasingly used to explicate the mechanics of disease propagation, impact of controls, and sensitivity of countermeasures. The authors demonstrate use of a Rift Valley Fever (RVF) model to study efficacy of countermeasures to disease transmission parameters. RVF is a viral infectious disease that propagates through infected mosquitoes and primarily affects animals but also humans. Vaccines exist to protect against the disease but there is lack of data comparing efficacy of vaccination with alternative countermeasures such as managing mosquito population or destroying infected livestock. This paper presents a compartmentalized multispecies deterministic ordinary differential equation model of RVF propagation among livestock through infected Aedes and Culex mosquitoes and exercises the model to study the efficacy of vector adulticide, vector larvicide, livestock vaccination, and livestock culling on livestock population. Results suggest that livestock vaccination and culling offer the greatest benefit in terms of reducing livestock morbidity and mortality.

scholarly journals Definition and estimation of an actual reproduction number describing past infectious disease transmission: application to HIV epidemics among homosexual men in Denmark, Norway and Sweden

2004 ◽  
Vol 132 (6) ◽  
pp. 1139-1149 ◽  
Author(s):  
E. J. AMUNDSEN ◽  
H. STIGUM ◽  
J.-A. RØTTINGEN ◽  
O. O. AALEN
Keyword(s):  
Infectious Disease ◽  
Disease Transmission ◽  
Reproduction Number ◽  
Infectious Period ◽  
Secondary Case ◽  
Time Interval ◽  
Homosexual Men ◽  
Infectious Disease Transmission ◽  
A Value ◽  
The Common

Prevalence and incidence measures are the common way to describe epidemics. The reproduction number supplies information on the potential for growth or decline of an epidemic. We define an actual reproduction number for infectious disease transmission that has taken place. An estimator is suggested, based on the number of new infections observed in a given time-interval, the number of those infected at the start of the interval, and the length of the infectious period. That estimator is applied to HIV among men having sex with other men over the period, 1977–1995, in Scandinavia. The actual reproduction number was estimated with acceptable certainty from the period, 1981–1982, yielding a value of 15 secondary cases. A value of less than one secondary case was assessed for the period, 1988–1995, in Denmark and Sweden. The actual reproduction number gives us some additional understanding of the dynamics of epidemics, compared with prevalence and incidence curves.

Evaluating interventions againstSalmonellain broiler chickens: applying synthesis research in support of quantitative exposure assessment

2011 ◽  
Vol 140 (5) ◽  
pp. 925-945 ◽  
Author(s):  
O. BUCHER ◽  
A. FAZIL ◽  
A. RAJIĆ ◽  
A. FARRAR ◽  
R. WILLS ◽  
...  
Keyword(s):  
Exposure Assessment ◽  
Broiler Chickens ◽  
Broiler Chicken ◽  
Full Potential ◽  
Baseline Scenario ◽  
Scoping Study ◽  
Hypothetical Scenario ◽  
Meta Analyses ◽  
On Farm ◽  
Multiple Scenarios

SUMMARYA scoping study and systematic review-meta-analyses (SR-MAs) were conducted to evaluate the effectiveness of various interventions forSalmonellain broiler chicken, from grow-out farm to secondary processing. The resulting information was used to inform a quantitative exposure assessment (QEA) comparing various control options within the context of broiler chicken production in Ontario, Canada. Multiple scenarios, including use of two separate on-farm interventions (CF3 competitive exclusion culture and a 2% lactose water additive), a package of processing interventions (a sodium hydroxide scald water disinfectant, a chlorinated post-evisceration spray, a trisodium phosphate pre-chill spray and chlorinated immersion chilling) a package consisting of these farm and processing interventions and a hypothetical scenario (reductions in between-flock prevalence and post-transport concentration), were simulated and compared to a baseline scenario. The package of on-farm and processing interventions was the most effective in achieving relative reductions (compared to baseline with no interventions) in the concentration and prevalence ofSalmonellaby the end of chilling ranging from 89·94% to 99·87% and 43·88% to 87·78%, respectively. Contaminated carcasses entering defeathering, reductions in concentration due to scalding and post-evisceration washing, and the potential for cross-contamination during chilling had the largest influence on the model outcomes under the current assumptions. Scoping study provided a transparent process for mapping out and selecting promising interventions, while SR-MA was useful for generating more precise and robust intervention effect estimates for QEA. Realization of the full potential of these methods was hampered by low methodological soundness and reporting of primary research in this area.

The External Relations of the EEC, and Its Internal Problems

1975 ◽  
Vol 10 (2) ◽  
pp. 159-166 ◽  
Author(s):  
Emile Noël
Keyword(s):  
Cold War ◽  
Suez Crisis ◽  
Internal Development ◽  
Military Threat ◽  
External Relations ◽  
Speed Up ◽  
Political Background ◽  
The Common ◽  
The Cold War ◽  
European Defence Community

EXTERNAL POLICY HAS HAD QUITE A LOT TO DO WITH THE establishment of the Communities. The cold war was in fill1 swing when the first of them, the European Coal and Steel Community, came into operation in 1952. The projected European Defence Community was an attempt to find a European response to the Soviet military threat which was the obsession of the early 1950s. A few years later, the trouble in which the European countries found themselves - over oil afier the Suez crisis, at the end of 1956, undoubtedly served to speed up the negotiation and conclusion of the Treaties of Rome. However, this political background did not affect the actual content of the Common Market Treaty, which as regards external relations is quite on traditional lines. It keeps the assertion of the Community's external identity and responsibilities very definitely subordinated to its internal development, that is, to the achievement of economic integration.

scholarly journals Xerostomia (dry mouth) in patients with COVID-19: a case series

2021 ◽  
Author(s):  
Yaser Fathi ◽  
Elaheh Ghasemzadeh Hoseini ◽  
Fatemeh Atoof ◽  
Reza Mottaghi
Keyword(s):  
Early Diagnosis ◽  
Treatment Outcomes ◽  
Disease Transmission ◽  
Case Series ◽  
Hospitalized Patients ◽  
Dry Mouth ◽  
Prodromal Symptom ◽  
The Common

Introduction: Dry mouth has been reported as a symptom of COVID-19. In this study, xerostomia (dry mouth) was reported in patients with COVID-19. Materials & methods: Dry mouth was assessed in hospitalized patients with COVID-19 daily until all of the dry mouth symptoms resolved. Results: Dry mouth appeared in 60% of cases 3–4 days before as prodromal symptom and in others, simultaneously or 1–2 days after the onset of other symptoms. In most cases, with starting the treatment, dry mouth gradually disappeared. Conclusion: Xerostomia in COVID-19 could occur before the common symptoms. Therefore, it could be hypothesized that it could be used for early diagnosis, quarantine and treatment. As a result, disease transmission might be prevented and the best treatment outcomes could be achieved.

A Study of the Prevalence of Male Intrameatal Warts Using Meatoscopy in a Genitourinary Medicine Department

1995 ◽  
Vol 6 (3) ◽  
pp. 184-187 ◽  
Author(s):  
P M Nathan ◽  
V C Thompson ◽  
G Sharmacharja ◽  
J Hawkswell ◽  
B Fogarty
Keyword(s):  
Disease Transmission ◽  
Genital Warts ◽  
Cross Sectional Study ◽  
Anogenital Warts ◽  
Cross Sectional ◽  
Medicine Department ◽  
Female Partners ◽  
The Common ◽  
And Control ◽  
Male Genital

A cross-sectional study is undertaken to determine the prevalence of male intrameatal and distal urethral warts, using meatoscopy. A group of 169 patients presenting for anogenital warts and a group of 74 unselected patients attending the Department for a variety of reasons during the study period, were examined. Twenty-one patients (13.5%) out of 155 patients with anogenital or related warts had external warts at the meatus. Of these 21 cases, 12 (57.1%) had further extension of their warts into the distal urethra. Fifteen other cases of intrameatal and distal urethral warts were detected in the absence of external warts at the meatus. Twenty-three cases out of 107 males with genital warts (21.5%) were found to have intrameatal or distal urethral warts, thus reflecting the common occurrence of these lesions. A highly significant association between the presence of intrameatal/distal urethral warts and the presence of male genital warts was found ( P=0.003). One hundred and fifty-three repeat meatoscopic examinations were carried out, 6 weeks after their first examination. Three new cases of intrameatal/distal urethral warts were found. Intrameatal and distal urethral warts occurred from a depth of 5 mm to 25 mm. One hundred and eighty-three female partners of the study patients were examined. An association between the presence of intrameatal/distal urethral warts and female anogenital warts was found ( P=0.028). No corroborating association between the presence of male and female anogenital warts was found ( P=0.47). This observation may have a bearing on disease transmission and control. The detection of intrameatal/distal urethral warts will be important in achieving successful treatment of male anogenital warts.

scholarly journals SARS-CoV-2 (COVID-19): New Discoveries and Current Challenges

2020 ◽  
Vol 10 (10) ◽  
pp. 3641 ◽  
Author(s):  
Ghazaleh Jamalipour Soufi ◽  
Ali Hekmatnia ◽  
Mahmoud Nasrollahzadeh ◽  
Nasrin Shafiei ◽  
Mohaddeseh Sajjadi ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Development Process ◽  
Clinical Symptoms ◽  
Future Directions ◽  
Health Crisis ◽  
Pattern Control ◽  
Infection Source ◽  
Speed Up ◽  
Current Outbreak ◽  
And Control

SARS-CoV-2 (COVID-19) has today multiplied globally and various governments are attempting to stop the outbreak of the disease escalation into a worldwide health crisis. At this juncture, readiness, candor, clarity, and partaking of data are of paramount importance to speed up factual evaluation and starting pattern control activities, including serendipitous findings. Owing to the involvement of COVID-19, many facts regarding virulence, pathogenesis, and the real viral infection source and/or transmission mode still need to be addressed. The infected patients often present clinical symptoms with fever, dyspnea, fatigue, diarrhea, vomiting, and dry cough, as well as pulmonary, infiltrates on imaging. Extensive measures to decrease person-to-person transmission of COVID-19 are being implemented to prevent, recognize, and control the current outbreak as it is very similar to SARS-CoV in its clinical spectrum, epidemiology, and pathogenicity. In response to this fatal disease and disruptive outbreak, it is extremely vital to expedite the drug development process to treat the disease and vaccines for the prevention of COVID-19 that would help us defeat this pandemic expeditiously. This paper sums up and unifies the study of virological aspects, disease transmission, clinically administered techniques, therapeutics options, managements, future directions, designing of vaccines, and news dissemination pertaining to COVID-19.

scholarly journals Study on Post-editing for Machine Translation of Railway Engineering Texts

2021 ◽  
Vol 96 ◽  
pp. 05001
Author(s):  
Yuting Li ◽  
Xiuying Lu
Keyword(s):  
Machine Translation ◽  
Construction Projects ◽  
High Speed ◽  
Rapid Development ◽  
Common Error ◽  
Translation Quality ◽  
Speed Up ◽  
Railway Engineering ◽  
The Common

With rapid development of China's railways, there are more overseas construction projects and technical exchanges in the field of railway engineering, which have generated widespread demands for translation. To meet the increasingly growing demands for translation of railway engineering texts, the mode of machine translation plus post editing (MTPE) has been frequently applied besides traditional human translation (HT) for the combination of translation quality and efficiency. Through the case study of post editing in the machine translation of China's High-Speed Railway by Google Translate, this paper discusses the common error types of machine translation in railway engineering translation, and puts forward corresponding post editing strategies, so as to provide references for MTPE of railway engineering translation in the future. It is hoped that research on post editing in the mode of machine translation for railway engineering texts may improve the translation quality and efficiency, thus helping speed up the process of China's railway going global.

scholarly journals Timber-colonizing gram-negative bacteria as potential causative agents of respiratory diseases in woodworkers

2022 ◽  
Author(s):  
Angelina Wójcik-Fatla ◽  
Barbara Mackiewicz ◽  
Anna Sawczyn-Domańska ◽  
Jacek Sroka ◽  
Jan Siwiec ◽  
...  
Keyword(s):  
Wood Dust ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Wood Processing ◽  
Causative Agents ◽  
Long Time ◽  
Speed Up ◽  
The Common ◽  
Organic Dust Toxic Syndrome ◽  
Radiographic Changes

Abstract Occurrence Gram-negative bacteria occur commonly in the inner tissues of stored coniferous and deciduous timber, showing a marked variation in numbers. The greatest maximal numbers are found in the sapwood of coniferous timber. The common constituents of the Gram-negative biota are potentially pathogenic species of Enterobacteriaceae family of the genera Rahnella, Pantoea, Enterobacter, and Klebsiella. The air of wood-processing facilities is polluted with the wood-borne Gram-negative bacteria and produced by them endotoxin, as demonstrated worldwide by numerous studies. Effects There are three potential pathways of the pathogenic impact of wood-borne Gram-negative bacteria on exposed woodworkers: allergic, immunotoxic, and infectious. Allergic impact has been underestimated for a long time with relation to Gram-negative bacteria. Hopefully, the recent demonstration of the first documented case of hypersensitivity pneumonitis (HP) in woodworkers caused by Pantoea agglomerans which developed in extremely large quantities in birch sapwood, would speed up finding of new wood-related cases of HP caused by Gram-negative bacteria. The second pathway is associated with endotoxin, exerting strong immunotoxic (excessively immunostimulative) action. It has been demonstrated that endotoxin is released into wood dust in the form of nano-sized microvesicles, by peeling off the outer membrane of bacteria. Endotoxin microvesicles are easily inhaled by humans together with dust because of small dimensions and aerodynamic shape. Afterwards, they cause a nonspecific activation of lung macrophages, which release numerous inflammatory mediators causing an inflammatory lung reaction, chest tightness, fever, gas exchange disorders, and bronchospasm, without radiographic changes. The resulting disease is known as “Organic Dust Toxic Syndrome” or “toxic pneumonitis.” The potential third pathway of pathogenic impact is infection. The suspected species is Klebsiella pneumoniae that may occur commonly in wood dust; however, until now this pathway has not been confirmed. Conclusion Summarizing, Gram-negative bacteria-inhabiting timber should be considered, besides filamentous fungi and actinobacteria, as important risk factors of occupational disease in woodworkers that could be either HP with allergenic background or toxic pneumonitis elicited by endotoxin.

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