scholarly journals A Brief Theory of Epidemic Kinetics

Biology ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 134
Author(s):  
François Louchet
Keyword(s):  
Reproductive Rate ◽  
Contact Duration ◽  
Protection Measures ◽  
Contagious Diseases ◽  
Exponential Increase ◽  
Exposed Population ◽  
Stable Attractor ◽  
Recovery Response ◽  
Average Individual ◽  
Viral Respiratory

In the context of the COVID-19 epidemic, and on the basis of the Theory of Dynamical Systems, we propose a simple theoretical approach for the expansion of contagious diseases, with a particular focus on viral respiratory tracts. The infection develops through contacts between contagious and exposed people, with a rate proportional to the number of contagious and of non-immune individuals, to contact duration and turnover, inversely proportional to the efficiency of protection measures, and balanced by the average individual recovery response. The obvious initial exponential increase is readily hindered by the growing recovery rate, and also by the size reduction of the exposed population. The system converges towards a stable attractor whose value is expressed in terms of the “reproductive rate” R0, depending on contamination and recovery factors. Various properties of the attractor are examined, and particularly its relations with R0. Decreasing this ratio below a critical value leads to a tipping threshold beyond which the epidemic is over. By contrast, significant values of the above ratio may bring the system through a bifurcating hierarchy of stable cycles up to a chaotic behaviour.

scholarly journals A Brief Theory of Epidemic Kinetics

2020 ◽  
Author(s):  
Francois Louchet
Keyword(s):  
Simple Model ◽  
Immunological Response ◽  
Critical Value ◽  
Contact Duration ◽  
Protection Measures ◽  
Contagious Diseases ◽  
Exponential Increase ◽  
Exposed Population ◽  
Stable Attractor ◽  
Viral Respiratory

In the context of the COVID-19 epidemic, and on the basis of the Theory of Dynamical Systems, we propose a simple model for the expansion of contagious diseases, with a particular focus on viral respiratory tracts. The infection develops through contacts between contagious and exposed people, with a rate proportional to contact duration and turnover, inversely proportional to the efficiency of protection measures, and balanced by the average immunological response. The obvious initial exponential increase is readily hindered by the size reduction of the exposed population. The system converges towards a stable attractor whose value is expressed in terms of the ratio C/D of contamination vs decay factors. Decreasing this ratio below a critical value leads to a tipping point beyond which the epidemic is over. By contrast, significant values of C/D may bring the system through a bifurcating hierarchy of stable cycles up to a chaotic behaviour.

Population size and density in two European pond turtle populations of central Italy

2020 ◽  
Vol 41 (4) ◽  
pp. 461-467
Author(s):  
Marco A.L. Zuffi ◽  
Alice Spinelli ◽  
Vuk Ikovic ◽  
Marco Mangiacotti ◽  
Roberto Sacchi ◽  
...  
Keyword(s):  
Sexual Size Dimorphism ◽  
Central Italy ◽  
Reproductive Rate ◽  
Population Estimates ◽  
Protection Measures ◽  
Emys Orbicularis ◽  
Pond Turtle ◽  
Natural Park ◽  
Two Populations ◽  
North Western

Abstract Two populations of the European pond turtle were studied employing capture, marking and recapture (CMR) techniques to determine population density and abundance in natural and protected areas within the Regional Natural park Migliarino San Rossore Massaciuccoli in north western Tuscany, Italy. The results indicated strong sexual size dimorphism in both populations, with males smaller than females. In one area Emys orbicularis was in general smaller in size with a very low reproductive rate (three out of 25 adult females were gravid), which contrasted with a second population where 20 out of 42 females were gravid. Population estimates indicated 79 turtles were present in the first area (0.34 ha) and 61 turtles in the second area (0.58 ha), giving an overall density estimate of 183.6 turtles/ha and 146.7 turtles/ha respectively. Whilst our results are similar to those found in other areas of Europe, they diverge from other regions, suggesting that sampling and monitoring techniques should be standardized to obtain comparable data that will enable conservation and protection measures to be recommended.

scholarly journals SARS-CoV-2 Among Migrants Recently Arrived in Europe From Low- and Middle-Income Countries: Containment Strategies and Special Features of Management in Reception Centers

2021 ◽  
Vol 9 ◽  
Author(s):  
Silvia Fabris ◽  
Gabriella d'Ettorre ◽  
Ornella Spagnolello ◽  
Alessandro Russo ◽  
Maurizio Lopalco ◽  
...  
Keyword(s):  
Cultural Barriers ◽  
Public Health Issue ◽  
Prevention Measures ◽  
Protection Measures ◽  
Systematic Screening ◽  
Middle Income ◽  
Epidemiological Analysis ◽  
Contagious Diseases ◽  
Individual Protection ◽  
Self Protection

Despite the “migrants and COVID-19” topic has been neglected since felt marginal concerning other aspects of the SARS-CoV-2 pandemic, it represents a relevant public health issue in the European countries. This report describes COVID-19 containment strategies adopted in a large Italian reception center hosting recently arrived asylum-seeker migrants. Risk assessment and prevention measures adopted were described. Geo-spatial epidemiological analysis of the outbreak was reported. Significant gaps in the knowledge of self-protection measures from contagious diseases and in the perception of the pandemic risk were observed in migrants; health promotion activities, targeted to remove cultural barriers and improve behaviors appropriate to individual protection, were able to fulfill this gap. In low-resource settings, especially in closed communities, the implementation of social distancing strategies, the systematic use of individual protection devices, and active syndromic surveillance are essential tools to limit the risk of outbreaks. In the event of an outbreak, it is relevant to rapidly activate containment procedures based on systematic screening, isolation, and quarantine, taking into consideration the limits of tracing contacts within a closed community. Not being able to trace certain contacts, the geo-spatial epidemiological analysis of cases distribution could be key in the management of the outbreak. Interestingly, positive cases identified in our facility were all clinically pauci-symptomatic or asymptomatic. Dedicated strategies are needed to minimize the chance of SARS-CoV-2 transmission in a limited space such as reception centers and a vulnerable population such as migrants.

Noise-Induced Balance Loss? Rethinking Clinical Implications of Noise Exposure

2019 ◽  
Vol 4 (6) ◽  
pp. 1418-1422
Author(s):  
Bre Myers ◽  
J. Andrew Dundas
Keyword(s):  
Vestibular System ◽  
Noise Exposure ◽  
Balance Control ◽  
Scope Of Practice ◽  
Hearing Conservation ◽  
Exposed Population ◽  
Auditory Systems ◽  
Current Article ◽  
Balance Loss ◽  
Cross System

Purpose The primary aim of the current article is to provide a brief review of the literature regarding the effects of noise exposure on the vestibular and balance control systems. Although the deleterious effects of noise on the auditory system are widely known and continue to be an active area of research, much less is known regarding the effects of noise on the peripheral vestibular system. Audiologists with working knowledge of how both systems interact and overlap are better prepared to provide comprehensive care to more patients as assessment of both the auditory and vestibular systems has been in the audiologists' scope of practice since 1992. Method A narrative review summarizes salient findings from the archival literature. Results Temporary and permanent effects on vestibular system function have been documented in multiple studies. Hearing conservation, vestibular impairment, and fall risk reduction may be more intimately related than previously considered. Conclusions A full appreciation of both the vestibular and auditory systems is necessary to address the growing and aging noise-exposed population. More cross-system studies are needed to further define the complex relationship between the auditory and vestibular systems to improve comprehensive patient care.

Are you at risk? Perceptions of vulnerability to contagious and non-contagious diseases

2011 ◽  
Author(s):  
Camille D. Basilio ◽  
Kelli Byrnes ◽  
Angela G. Pirlott ◽  
Virginia S. Y. Kwan ◽  
Leona S. Aiken
Keyword(s):  
At Risk ◽  
Risk Perceptions ◽  
Contagious Diseases

Coronavirus diseases and pregnancy: COVID-19,SARS, and MERS

2020 ◽  
pp. 276-289
Author(s):  
Mobina Fathi ◽  
Kimia Vakili ◽  
Niloofar Deravi
Keyword(s):  
Pregnant Women ◽  
Intrauterine Growth Retardation ◽  
Negative Impact ◽  
World Health ◽  
Wuhan City ◽  
Intrauterine Growth ◽  
Exponential Increase ◽  
The World ◽  
Health Organization ◽  
Respiratory Droplets

Around the end of December 2019, a new beta-coronavirus from Wuhan City, Hubei Province, China began to spread rapidly. The new virus, called SARS-CoV-2, which could be transmitted through respiratory droplets, had a range of mild to severe symptoms, from simple cold in some cases to death in others. The disease caused by SARS-CoV-2 was named COVID-19 by WHO and has so far killed more people than SARS and MERS. Following the widespread global outbreak of COVID-19, with more than 132758 confirmed cases and 4955 deaths worldwide, the World Health Organization declared COVID-19 a pandemic disease in January 2020. Earlier studies on viral pneumonia epidemics has shown that pregnant women are at greater risk than others. During pregnancy, the pregnant woman is more prone to infectious diseases. Research on both SARS-CoV and MERS-CoV, which are pathologically similar to SARS-CoV-2, has shown that being infected with these viruses during pregnancy increases the risk of maternal death, stillbirth, intrauterine growth retardation and, preterm delivery. With the exponential increase in cases of COVID-19 throughout the world, there is a need to understand the effects of SARS-CoV-2 on the health of pregnant women, through extrapolation of earlier studies that have been conducted on pregnant women infected with SARS-CoV, and MERS-CoV. There is an urgent need to understand the chance of vertical transmission of SARS-CoV-2 from mother to fetus and the possibility of the virus crossing the placental barrier. Additionally, since some viral diseases and antiviral drugs may have a negative impact on the mother and fetus, in which case, pregnant women need special attention for the prevention, diagnosis, and treatment of COVID-19.

Economic models of Environment monitoring under imperfect information and high Costs

2014 ◽  
pp. 99-122
Author(s):  
M. Levin ◽  
K. Matrosova
Keyword(s):  
Environmental Monitoring ◽  
Environmental Regulation ◽  
Environmental Economics ◽  
Imperfect Information ◽  
Central Element ◽  
Economic Models ◽  
Environment Monitoring ◽  
Nature Protection ◽  
Protection Measures ◽  
Effective System

The paper considers monitoring of environmental change as the central element of environmental regulation. Monitoring, as each kind of principalagent relations, easily gives rise to corruptive behavior. In the paper we analyze economic models of environmental monitoring with high costs, incomplete information and corruption. These models should be the elements of environmental economics and are needed to create an effective system of nature protection measures.

Method for Assessing the Ecological Risk to the Population in Areas Outside the Planning Zones of Emergency Protection Measures Around the NPP

2020 ◽  
Vol 17 (5) ◽  
pp. 34-47
Author(s):  
V. M. Polyakov ◽  
Z. S. Agalarov
Keyword(s):  
Ecological Risk ◽  
Environmental Risk ◽  
Risk Taking ◽  
Late Stage ◽  
Simulation Modeling ◽  
Radiation Accident ◽  
Emergency Protection ◽  
Protection Measures ◽  
Vector Criterion

The article offers a method for assessing the environmental risk in the territories adjacent to the planning zone of emergency protection measures around the NPP. The method is based on simulation modeling of territory pollution, which is formed at the late stage of a radiation accident and zoning of territories by risk, taking into account the characteristics of the population’s life in a potentially dangerous territory. A vector criterion of environmental risk is proposed that allows zoning these territories according to the degree of danger to the population.

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