scholarly journals Opposite outcomes of coinfection at individual and population scales

2018 ◽  
Vol 115 (29) ◽  
pp. 7545-7550 ◽  
Author(s):  
Erin E. Gorsich ◽  
Rampal S. Etienne ◽  
Jan Medlock ◽  
Brianna R. Beechler ◽  
Johannie M. Spaan ◽  
...  

Coinfecting parasites and pathogens remain a leading challenge for global public health due to their consequences for individual-level infection risk and disease progression. However, a clear understanding of the population-level consequences of coinfection is lacking. Here, we constructed a model that includes three individual-level effects of coinfection: mortality, fecundity, and transmission. We used the model to investigate how these individual-level consequences of coinfection scale up to produce population-level infection patterns. To parameterize this model, we conducted a 4-y cohort study in African buffalo to estimate the individual-level effects of coinfection with two bacterial pathogens, bovine tuberculosis (bTB) and brucellosis, across a range of demographic and environmental contexts. At the individual level, our empirical results identified bTB as a risk factor for acquiring brucellosis, but we found no association between brucellosis and the risk of acquiring bTB. Both infections were associated with reductions in survival and neither infection was associated with reductions in fecundity. The model reproduced coinfection patterns in the data and predicted opposite impacts of coinfection at individual and population scales: Whereas bTB facilitated brucellosis infection at the individual level, our model predicted the presence of brucellosis to have a strong negative impact on bTB at the population level. In modeled populations where brucellosis was present, the endemic prevalence and basic reproduction number (R0) of bTB were lower than in populations without brucellosis. Therefore, these results provide a data-driven example of competition between coinfecting pathogens that occurs when one pathogen facilitates secondary infections at the individual level.

2013 ◽  
Vol 59 (4) ◽  
pp. 485-505 ◽  
Author(s):  
Jon E. Brommer

Abstract Individual-based studies allow quantification of phenotypic plasticity in behavioural, life-history and other labile traits. The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically significant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild populations, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that ‘scale up’ to population level processes and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated.


2017 ◽  
Author(s):  
Alex Mesoudi

AbstractHow do migration and acculturation (i.e. psychological or behavioral change resulting from migration) affect within- and between-group cultural variation? Here I answer this question by drawing analogies between genetic and cultural evolution. Population genetic models show that migration rapidly breaks down between-group genetic structure. In cultural evolution, however, migrants or their descendants can acculturate to local behaviors via social learning processes such as conformity, potentially preventing migration from eliminating between-group cultural variation. An analysis of the empirical literature on migration suggests that acculturation is common, with second and subsequent migrant generations shifting, sometimes substantially, towards the cultural values of the adopted society. Yet there is little understanding of the individual-level dynamics that underlie these population-level shifts. To explore this formally, I present models quantifying the effect of migration and acculturation on between-group cultural variation, for both neutral and costly cooperative traits. In the models, between-group cultural variation, measured using F statistics, is eliminated by migration and maintained by conformist acculturation. The extent of acculturation is determined by the strength of conformist bias and the number of demonstrators from whom individuals learn. Acculturation is countered by assortation, the tendency for individuals to preferentially interact with culturally-similar others. Unlike neutral traits, cooperative traits can additionally be maintained by payoff-biased social learning, but only in the presence of strong sanctioning institutions. Overall, the models show that surprisingly little conformist acculturation is required to maintain realistic amounts of between-group cultural diversity. While these models provide insight into the potential dynamics of acculturation and migration in cultural evolution, they also highlight the need for more empirical research into the individual-level learning biases that underlie migrant acculturation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Hernández-Orallo ◽  
Bao Sheng Loe ◽  
Lucy Cheke ◽  
Fernando Martínez-Plumed ◽  
Seán Ó hÉigeartaigh

AbstractSuccess in all sorts of situations is the most classical interpretation of general intelligence. Under limited resources, however, the capability of an agent must necessarily be limited too, and generality needs to be understood as comprehensive performance up to a level of difficulty. The degree of generality then refers to the way an agent’s capability is distributed as a function of task difficulty. This dissects the notion of general intelligence into two non-populational measures, generality and capability, which we apply to individuals and groups of humans, other animals and AI systems, on several cognitive and perceptual tests. Our results indicate that generality and capability can decouple at the individual level: very specialised agents can show high capability and vice versa. The metrics also decouple at the population level, and we rarely see diminishing returns in generality for those groups of high capability. We relate the individual measure of generality to traditional notions of general intelligence and cognitive efficiency in humans, collectives, non-human animals and machines. The choice of the difficulty function now plays a prominent role in this new conception of generality, which brings a quantitative tool for shedding light on long-standing questions about the evolution of general intelligence and the evaluation of progress in Artificial General Intelligence.


2021 ◽  
Vol 12 ◽  
Author(s):  
Chao Li ◽  
Hugh Barclay ◽  
Bernard Roitberg ◽  
Robert Lalonde

Compensatory growth has been observed in forests, and it also appears as a common phenomenon in biology. Though it sometimes takes different names, the essential meanings are the same, describing the accelerated growth of organisms when recovering from a period of unfavorable conditions such as tissue damage at the individual level and partial mortality at the population level. Diverse patterns of compensatory growth have been reported in the literature, ranging from under-, to compensation-induced-equality, and to over-compensation. In this review and synthesis, we provide examples of analogous compensatory growth from different fields, clarify different meanings of it, summarize its current understanding and modeling efforts, and argue that it is possible to develop a state-dependent model under the conceptual framework of compensatory growth, aimed at explaining and predicting diverse observations according to different disturbances and environmental conditions. When properly applied, compensatory growth can benefit different industries and human society in various forms.


Author(s):  
Farah Ahmad ◽  
Jamie Jianmin Wang ◽  
Christo El Morr

The current chapter systematically reviewed literature on online mindfulness interventions. Electronic databases were searched from 2005 to July 2016. The aim was to examine the nature of online mindfulness interventions, design features, and their effectiveness in improving symptoms of depression, anxiety, and stress. The review of selected studies shows that online delivery of mindfulness psycho-education and practice is an area in its infancy. There is evidence that online mindfulness interventions can have a positive impact on mental health in terms of stress, depression, and anxiety; however, large sample studies are needed in order to have conclusive results. Moreover, the extension of online mindfulness interventions beyond the individual level to include a community dimension, such as virtual community features, and a focus on the social determinants of health, needs to be explored in future. The online mindfulness intervention could be a cost-effective way to scale up the promotion of mental wellbeing.


Author(s):  
Emma Rary ◽  
Sarah M. Anderson ◽  
Brandon D. Philbrick ◽  
Tanvi Suresh ◽  
Jasmine Burton

The health of individuals and communities is more interconnected than ever, and emergent technologies have the potential to improve public health monitoring at both the community and individual level. A systematic literature review of peer-reviewed and gray literature from 2000-present was conducted on the use of biosensors in sanitation infrastructure (such as toilets, sewage pipes and septic tanks) to assess individual and population health. 21 relevant papers were identified using PubMed, Embase, Global Health, CDC Stacks and NexisUni databases and a reflexive thematic analysis was conducted. Biosensors are being developed for a range of uses including monitoring illicit drug usage in communities, screening for viruses and diagnosing conditions such as diabetes. Most studies were nonrandomized, small-scale pilot or lab studies. Of the sanitation-related biosensors found in the literature, 11 gathered population-level data, seven provided real-time continuous data and 14 were noted to be more cost-effective than traditional surveillance methods. The most commonly discussed strength of these technologies was their ability to conduct rapid, on-site analysis. The findings demonstrate the potential of this emerging technology and the concept of Smart Sanitation to enhance health monitoring at the individual level (for diagnostics) as well as at the community level (for disease surveillance).


Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 739 ◽  
Author(s):  
Elisa Frasnelli ◽  
Giorgio Vallortigara

Lateralization, i.e., the different functional roles played by the left and right sides of the brain, is expressed in two main ways: (1) in single individuals, regardless of a common direction (bias) in the population (aka individual-level lateralization); or (2) in single individuals and in the same direction in most of them, so that the population is biased (aka population-level lateralization). Indeed, lateralization often occurs at the population-level, with 60–90% of individuals showing the same direction (right or left) of bias, depending on species and tasks. It is usually maintained that lateralization can increase the brain’s efficiency. However, this may explain individual-level lateralization, but not population-level lateralization, for individual brain efficiency is unrelated to the direction of the asymmetry in other individuals. From a theoretical point of view, a possible explanation for population-level lateralization is that it may reflect an evolutionarily stable strategy (ESS) that can develop when individually asymmetrical organisms are under specific selective pressures to coordinate their behavior with that of other asymmetrical organisms. This prediction has been sometimes misunderstood as it is equated with the idea that population-level lateralization should only be present in social species. However, population-level asymmetries have been observed in aggressive and mating displays in so-called “solitary” insects, suggesting that engagement in specific inter-individual interactions rather than “sociality” per se may promote population-level lateralization. Here, we clarify that the nature of inter-individuals interaction can generate evolutionarily stable strategies of lateralization at the individual- or population-level, depending on ecological contexts, showing that individual-level and population-level lateralization should be considered as two aspects of the same continuum.


2017 ◽  
Vol 2 (1) ◽  
pp. 88-123 ◽  
Author(s):  
Dominic Burbidge ◽  
Nic Cheeseman

AbstractPolitical economy comparisons of Kenya and Tanzania have often found the political salience of ethnicity to be far higher in the former than the latter, with a negative impact on intercommunal trust. This difference has tended to be explained on the basis of the different kinds of leadership that the two countries experienced after independence. However, these findings have typically been demonstrated using aggregate or survey data. This paper assesses the salience of ethnicity at the individual level for the first time, deploying monetized two-round trust games in urban Kenya and Tanzania. The experimental games isolate the comparative impact of common knowledge of ethnicity and integrity among a quasi-random selection of 486 citizens. Verifying previous findings, we observe higher levels of trust and trustworthiness in Tanzania as compared with Kenya. Further, in comparison with Kenya, any shared knowledge of ethnic identities in Tanzania leads players to transfer fewer resources, while common knowledge that both players are “honest” led to higher transfers there than in Kenya. These results provide robust evidence of higher levels of trust in Tanzania, and of the negative effect in that country of common knowledge of ethnicity on levels of cooperation. The findings demonstrate the way in which political context can shape the impact of ethnic diversity, and encourage further experimental research that looks at the intersubjective dynamics of social cooperation.


2020 ◽  
Vol 65 (supp01) ◽  
pp. 117-138
Author(s):  
JINXIAN WANG ◽  
CHEN WANG ◽  
YAN ZHANG

Since 2010, China’s miraculous growth has come to a halt and has shown steady deceleration. To re-accelerate economic growth, stimulating domestic consumption is a crucial way with fighting poverty as the key step. This paper attempts to explore the impact of poverty on resident consumption in China over the last four decades. Based on provincial data, we first simulate income distribution at the individual level and provide moderate poverty profiles at the provincial level. The empirical analyses are then conducted to gauge the poverty impacts using the estimated poverty index. Results show that (1) moderate poverty has decreased sharply in China, with the best achievement in Beijing, Shanghai and Guangdong; (2) moderate poverty exerts a significantly negative impact on resident consumption; and (3) when poverty increases, resident consumption on household equipment decreases the most, while resident consumption on food, transportation, and telecommunication decreases the least.


Behaviour ◽  
2015 ◽  
Vol 152 (10) ◽  
pp. 1291-1306 ◽  
Author(s):  
A.D. Kelley ◽  
M.M. Humphries ◽  
A.G. McAdam ◽  
Stan Boutin

Both juvenile and adult animals display stable behavioural differences (personality), but lifestyles and niches may change as animals mature, raising the question of whether personality changes across ontogeny. Here, we use a wild population of red squirrels to examine changes in activity and aggression from juvenile to yearling life stages. Personality may change at the individual level (individual stability), population level (mean level stability), and relative to other individuals (differential stability). We calculated all three types of stability, as well as the structural stability of the activity–aggression behavioural syndrome. Within individuals, both activity and aggression scores regressed towards the mean. Differential stability was maintained for activity, but not aggression. Structural stability was maintained; however, the activity–aggression correlation increased in squirrels that gained territories later in the season. These results suggest that personality undergoes some changes as animals mature, and that the ontogeny of personality can be linked to environmental changes.


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