Search results for "Persistence"
showing 10 items of 243 documents
The impact of variable hatching rates on parasite control: a model of an aquatic ectoparasite in a Finnish fish farm
2006
Summary 1 Many parasites of medical and veterinary importance infect via free-living stages that undergo a period of development in the environment before seeking a host. Frequently, considerable variation is observed in the development rates of these stages, such that some individuals may be considered to occupy distinct subpopulations, similar to a plant's seed bank. Under certain conditions, these subpopulations may act as a reservoir for the parasite, buffering it from the impact of management strategies and reducing control success. 2 We assessed the impact of intraspecific variation in development rates on parasite control by developing a population dynamic model of the ectoparasite A…
Using probability of extinction to evaluate the ecological significance of toxicant effects
2000
A large component of uncertainty in ecological risk assessment (ERA) arises from the disparity between the time scale of toxicity measurements and the time scale of predictions of ERA models. It is difficult to make predictions about the persistence of populations from data from short-term toxicity tests. Reproductive toxicity tests provide data about how population growth rate (r) is reduced with toxicant exposure. Although reduction in r is believed to be one of the most important effects of toxicant exposure, its ecological significance has been difficult to quantify. For rotifers, r is typically reduced by 10 to 15% at no-observed-effect concentrations (NOEC). We investigated r reductio…
Control of Growth and Persistence of Listeria monocytogenes and β-Lactam-Resistant Escherichia coli by Thymol in Food Processing Settings
2020
The main objective of this study was to evaluate the efficacy of thymol in controlling environmental contamination in food processing facilities. The effect of thymol was tested as an agent to prevent planktonic and bacterial biofilm growth of twenty-five Listeria monocytogenes isolates from a variety of foods and five Escherichia coli isolates from a farm. The E. coli isolates were positive for extended spectrum &beta
Persistence in complex systems
2022
Persistence is an important characteristic of many complex systems in nature, related to how long the system remains at a certain state before changing to a different one. The study of complex systems' persistence involves different definitions and uses different techniques, depending on whether short-term or long-term persistence is considered. In this paper we discuss the most important definitions, concepts, methods, literature and latest results on persistence in complex systems. Firstly, the most used definitions of persistence in short-term and long-term cases are presented. The most relevant methods to characterize persistence are then discussed in both cases. A complete literature r…
Genomic Data from an Ancient European Battlefield Indicates On-Going Strong Selection on a Genomic Region Associated with Lactase Persistence Over th…
2020
Lactase persistence (LP), the continued expression of lactase into adulthood, is the most strongly selected single gene trait over the last 10,000 years in multiple human populations. It has been posited that the primary allele causing LP among Eurasians, rs4988235*T (Enattah et al. 2008), only rose to appreciable frequencies during the Bronze and Iron Ages (Mathieson et al 2015; Olalde et al. 2018), long after humans started consuming milk from domesticated animals. This rapid rise has been attributed to an influx of peoples from the Pontic-Caspian steppe that began around 5,000 years ago (Allentoft et al. 2015; Furholt et al. 2016). We investigate the spatiotemporal spread of LP through a…
The role of the accumulation of poverty and unemployment for health disadvantages
2020
Health inequality is an important aspect of how advantages and disadvantages are distributed within societies. We extend previous research by considering how trajectories of poverty and employment affect self-reported health among young adults. We use data from the German Socio-Economic Panel, restricting the analytical sample to those who were 25 to 45 year-old in 2005. We calculated the indexes that account for persistence and intensity of poverty and employment on 10-year-long individual-level employment and household-level poverty trajectories. Ordinal logit regression models show that both long-lasting poverty and short periods out of employment are detrimental for men’s health. In con…
Persistent joblessness and fertility intentions
2019
Background: The vast majority of demographic studies have approached and operationalised the notion of economic uncertainty using snapshot indicators. Hence, the complexity and diversity of individuals' employment careers were largely hidden. We posit that the persistence of joblessness - that is, repeated and close spells of joblessness - represents a crucial marker of economic uncertainty in the realm of fertility (intention) research. Objective: We aim to explore the association between persistent joblessness of both members of the couple and women's fertility intentions among those who entered employment at least once in the last five years. Methods: We develop an index of persistent jo…
Persistence and turnover in regional unemployment disparities
1998
PEHKONEN J. and TERVO H. (1998) Reg. Studies, 32 , 445-458, Persistence and turnover in regional unemployment disparities. This study investigates persistence and turnover in regional unemployment disparities in Finland by examining time-series data on 10 labour districts and 423 municipalities. The data on the labour districts indicates that regional unemployment disparities are rather persistent and that steady-state unemployment rates differ considerably across the districts. The results on the municipality level data, however, suggest the presence of substantial intra-distribution dynamics and that the degree of persistence is less profound than the labour district data indicates. In al…
The Impact of Prescribed Dosage Assumptions on the Evaluation of Adherence and Persistence to Medication in Patients After Acute Myocardial Infarction
2021
Medication adherence is a significant problem in public health. Prescription-level pharmacy databases have great potential for monitoring actual drug adherence patterns at the healthcare system level. Many research papers have reported adherence estimates in different settings and populations. However, comparison between studies is not always straightforward due to different approaches taken when computing adherence. A crucial component to accurately estimate adherence is the availability of days’ supply information for each dispensing event. Reasonable assumptions regarding medication dosage have to be made, when this information is not available. In this study, we evaluate adherence and p…
Cytomegalovirus and inflammatory bowel disease: Is there a link?
2006
The objective of this report is to give an overall view of the epidemiological, clinical, diagnostic and therapeutic features of Cytomegalovirus (CMV) infection in inflammatory bowel disease (IBD). A review of published reports on this topic was carried out, with particular attention paid to the selection of patients included in studies and the diagnostic methods employed. CMV is frequently associated with IBD. In some cases, CMV infection is associated with a poor outcome but it is not clear which patients are more likely to be affected and in which stage of the disease. The use of anti-viral therapy in IBD is controversial and an empirical study with controls is needed. The natural histor…