Development and application of a dose–response model for Elizabethkingia spp

Elizabethkingia spp. are common environmental pathogens responsible for infections in more vulnerable populations. Although the exposure routes of concern are not well understood, some hospital-associated outbreaks have indicated possible waterborne transmission. In order to facilitate quantitative microbial risk assessment (QMRA) for Elizabethkingia spp., this study fit dose–response models to frog and mice datasets that evaluated intramuscular and intraperitoneal exposure to Elizabethkingia spp. The frog datasets could be pooled, and the exact beta-Poisson model was the best fitting model with optimized parameters α  = 0.52 and β = 86,351. Using the exact beta-Poisson model, the dose of Elizabethkingia miricola resulting in a 50% morbidity response (LD₅₀) was estimated to be approximately 237,000 CFU. The model developed herein was used to estimate the probability of infection for a hospital patient under a modeled exposure scenario involving a contaminated medical device and reported Elizabethkingia spp. concentrations isolated from hospital sinks after an outbreak. The median exposure dose was approximately 3 CFU/insertion event, and the corresponding median risk of infection was 3.4E-05. The median risk estimated in this case study was lower than the 3% attack rate observed in a previous outbreak, however, there are noted gaps pertaining to the possible concentrations of Elizabethkingia spp. in tap water and the most likely exposure routes. This is the first dose–response model developed for Elizabethkingia spp. thus enabling future risk assessments to help determine levels of risk and potential effective risk management strategies.     

Labour Market Regulation,Flexibility and Employment

ABSTRACT: Chronic unemployment and slow employment growth in some countries have led to calls for more labor-market “flexibility”. This paper defines the flexibility issue in terms of legally-mandated “severance”, a generalized employment cost linked to seniority. A mandated severance benefit can stand for a variety of programs including employer-provided employment guarantees, payments which must be made to laid-off workers, and compensation for wrongful discharge. Such a mandated cost can be seen as a payroll tax on the employer, raising the issue of tax incidence. Employers often take the view that labor costs are given and that mandated costs are simply add-ons to pre-existing cost levels. However, the literature on tax incidence suggests that a significant portion of “employer-paid” payroll taxes are shifted to labor in the form of lower wages. Such shifting should reduce the dis-employment effects attributed to severance. A model is provided of a firm upon which a severance mandate is imposed. Even at the micro level, the firm can shift some of the cost of severance to employees by lowering wages — although at the expense of higher turnover costs associated with increased quit rates. At the macro level, to the extent that firms reduce employment, there could be still further downward wage adjustments which would shift the severance burden to labor and mitigate the dis-employment effect. Ultimately, if the natural rate of unemployment is raised by severance mandates, the age-old question is raised of why wages do not fall in the face of labor surpluses. The true inflexibility to be explained, therefore, is in wage determination.     

Linking video chatting,phone calling,text messaging,and social media with peers to adolescent connectedness

For 14 days three times per day (6072 observations), adolescents (N = 207, M_age = 15.45 years) reported their digital (i.e., video chatting, texting, social media, and phone calling) communication with peers and their social connectedness. Controlling for in-person interactions, adolescents felt more connected in hours when they had communicated with peers by video chatting, texting, or social media, but not phone calling. Girls communicated with peers via text and social media more than boys, and boys talked on the phone more than girls. Boys who talked, texted, or video chatted more on average reported higher connectedness on average, whereas girls did not. As the links with connectedness were only found at the hourly- and not the daily level, results highlight that a sense of connectedness from digital media may be fleeting in nature.     

The effect of artificial light on bat richness and nocturnal soundscapes along an urbanization gradient in an arid landscape of central Peru

Urbanization usually reduces bat richness; however, the presence of green areas within cities and peripheral rural areas in arid ecosystems may provide microhabitats for some species. Light pollution is a major feature of urbanization, but its impact on bat behavior appears to be species-specific and previous studies have documented contrasting responses. Moreover, the effect of urbanization on bat species has been poorly studied in arid regions. We assessed the effect of artificial night light intensity (as a proxy of urbanization) on both bat occupancy and the acoustic space used (ASU) in an urbanization gradient in Peruvian central coast, based on passive acoustic recorders. We collected 26,169 recordings from 19 sites which resulted in 579 independent detections of 15 bat species. Variation in both ASU and species richness was best explained by artificial night light intensity. Species-specific effects of the artificial night light intensity based on a multi-species occupancy modeling showed that this covariate had a negative effect on occupancy for most of the bat species (12 species). ASU and both observed and posterior bat species richness were positively correlated, suggesting that ASU can be used as a proxy of bat richness. This study provides evidence that both bat richness and occupancy decrease with artificial light intensity; nevertheless, eight species used urban areas, similar to results found in other cities around the world.