Psychological game theory can provide rational-choice-based framing effects; frames influence beliefs, beliefs influence motivations. We explain this theoretically and explore empirical relevance ...experimentally. In a
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design of one-shot public good games we show that frames affect subjectʼs first- and second-order beliefs and contributions. From a psychological game-theoretic framework we derive two mutually compatible hypotheses about guilt aversion and reciprocity under which contributions are related to second- and first-order beliefs, respectively. Our results are consistent with either.
► Psychological game theory can explain framing effects in public goods experiments. ► We develop models of guilt aversion and reciprocity. ► Frames might influence beliefs, beliefs influence motivations and contributions. ► We ran one-shot public good experiments with four framing treatments. ► The results support the predictions.
Over the last two decades, an increasing number of reports have identified a decline in salmonid populations, possibly linked to infection with the parasite Tetracapsuloides bryosalmonae and the ...corresponding disease, that is, proliferative kidney disease (PKD). The life cycle of this myxozoan parasite includes sessile bryozoan species as invertebrate host, which facilitates the distribution of the parasite in running waters. As the disease outcome is temperature dependent, the impact of the disease on salmonid populations is increasing with global warming due to climate change. The goal of this review is to provide a detailed overview of measures to mitigate the effects of PKD on salmonid populations. It first summarizes the parasite life cycle, temperature‐driven disease dynamics and new immunological and molecular research into disease resistance and, based on this, discusses management possibilities. Sophisticated management actions focusing on local adaptation of salmonid populations, restoration of the riverine ecosystem and keeping water temperatures cool are necessary to reduce the negative effects of PKD. Such actions include temporary stocking with PKD‐resistant salmonids, as this may assist in conserving current populations that fail to reproduce.
Dishonest behavior significantly increases the cost of medical care provision. Upcoding of patients is a common form of fraud to attract higher reimbursements. Imposing audit mechanisms including ...fines to curtail upcoding is widely discussed among health care policy‐makers. How audits and fines affect individual health care providers' behavior is empirically not well understood. To provide new evidence on fraudulent behavior in health care, we analyze the effect of a random audit including fines on individuals' honesty by means of a novel controlled behavioral experiment framed in a neonatal care context. Prevalent dishonest behavior declines significantly when audits and fines are introduced. The effect is driven by a reduction in upcoding when being detectable. Yet upcoding increases when not being detectable as fraudulent. We find evidence that individual characteristics (gender, medical background, and integrity) are related to dishonest behavior. Policy implications are discussed.
Aquaculture is a rapidly growing field of food production. However, morbidity and mortality are higher in aquaculture species than in domestic animals. Bacterial diseases are a leading cause of ...farmed fish morbidity and are often treated with antimicrobials. Since most Swiss fish farms release effluents directly into surface water without treatment and since aquaculture fish are consumed by humans, antimicrobial resistance (AMR) and multi‐resistance in aquaculture fish are important for environmental and public health. In this study, AMR tests for 14 antimicrobials were performed on 1,448 isolates from 1,134 diagnostic laboratory submissions from farmed and ornamental fish submissions for the period from 2000 to 2017. Amoxicillin, gentamycin and norfloxacin had the lowest proportion of resistant samples. However, AMR was highly variable over time. Resistance proportions were higher in: (a) ornamental fish compared with farmed fish, (b) fish from recirculation systems compared with those from other farming systems and (c) isolates originating from skin compared with those originating from inner organs. Multiple resistances were common. The results of this study provide useful data for Swiss fish veterinarians and some interesting hypotheses about risk factors for AMR in aquaculture and pet fish in Switzerland. However, further research is needed to define risk factors.
Heterogeneity in immunity occurs across numerous disease systems with individuals from the same population having diverse disease outcomes. Proliferative kidney disease (PKD) caused by ...Tetracapsuloides bryosalmonae, is a persistent parasitic disease negatively impacting both wild and farmed salmonids. Little is known of how PKD is spread or maintained within wild susceptible populations.
We investigated an aspect of fish disease that has been largely overlooked, that is, the role of the host phenotypic heterogeneity in disease outcome. We examined how host susceptibility to T. bryosalmonae infection, and the disease PKD, varied across different infection life‐history stages and how it differs between naïve, re‐infected and persistently infected hosts.
We investigated the response to parasite exposure in host phenotypes with (a) different ages and (b) heterogeneous infection life histories. Among (a) the age phenotypes were young‐of‐the‐year (YOY) fish and juvenile 1+ fish (fish older than one) and, for (b) juvenile 1+ infection survivors were either re‐exposed or not re‐ exposed to the parasite and response phenotypes were assigned post‐hoc dependant on infection status. In fish not re‐exposed this included fish that cleared infection (CI) or had a persistent infection (PI). In fish re‐exposed these included fish that were re‐infected (RI), or re‐exposed and uninfected (RCI). We assessed both parasite‐centric (infection prevalence, parasite burden, malacospore transmission) and host‐centric parameters (growth rates, disease severity, infection tolerance and the immune response).
In (a), YOY fish, parasite success and disease severity were greater and differences in the immune response occurred, demonstrating an ontogenetic decline of susceptibility in older fish. In (b), in PI and RI fish, parasite success and disease severity were comparable. However, expression of several adaptive immunity markers was greater in RI fish, indicating concomitant immunity, as re‐exposure did not intensify infection.
We demonstrate the relevance of heterogeneity in infection life history on disease outcome and describe several distinctive features of immune ontogeny and protective immunity in this model not previously reported. The relevance of such themes on a population level requires greater research in many aquatic disease systems to generate clearer framework for understanding the spread and maintenance of aquatic pathogens.
Recently we have all become aware that different individuals react to disease in a different ways, resulting in diverse outcomes. This also happens underwater for aquatic wildlife in terms of how infection life‐history influences the immune response and infection rates within a population and contributes to the spread and maintenance of disease.
Variants of perch rhabdovirus (PRV) circulate across European percid farms via the fish trade. To trace their circulation, they are usually isolated by cell culture and subsequently identified ...genetically by sequencing partial or complete genes. Here, a newly developed nested PCR‐based method was used to amplify and sequence the complete N and P genes directly from clinical samples obtained during an outbreak on a farm as well as from four batches of fish sampled from two other farms in another country. In an attempt to trace the origin of the five detected viruses, their N and P sequences were concatenated and compared with related viruses. One virus found in pike‐perch was highly related to a virus isolated in 2016 in Belgium. Two other viruses detected on a single farm were distinct from one another, with one being almost identical to another virus isolated in 2016 in Belgium and the other being more closely related to a subgroup with different origins, France and Belgium. Two other viruses found in perch from a third farm were identical and were more related to a subgroup of viruses isolated in France. Identifying variants by a direct PCR approach will help to prevent further dissemination in farms.
Transmission paths in the distribution of proliferative kidney disease (PKD) of salmonids are still largely unknown. In this study, the role of goosander (Mergus merganser) as possible transport host ...for Tetracapsuloides bryosalmonae through faeces was examined. Goosander fledglings were fed exclusively with diseased brown trout (Salmo trutta fario). In all trout used for feeding, intratubular sporogonic stage of the parasite was confirmed histologically. Between one to 10 hours post‐feeding, the goosander faeces were sampled and tested for T. bryosalmonae DNA. In qPCR, only DNA fragments were found, and in conventional PCR, no amplification was confirmed. Therefore, we hypothesize that the role of goosander as transport hosts for T. bryosalmonae via their faeces can be neglected.
We present a field experiment to assess the effect of own and peer wage variations on actual work effort of employees with hourly wages. Work effort neither reacts to an increase of the own wage, nor ...to a positive or negative peer comparison. This result seems at odds with numerous laboratory experiments that show a clear own wage sensitivity on effort. In an additional real-effort laboratory experiment we show that explicit cost and surplus information that enables an exact calculation of an employer's surplus from the work contract is a crucial prerequisite for a positive wage—effort relation. This demonstrates that an employee's reciprocity requires a clear assessment of the surplus at stake.
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