Bridging scales in the evolution of infectious disease life histories: theory

A significant goal of recent theoretical research on pathogen evolution has been to develop theory that bridges within- and between-host dynamics. The main approach used to date is one that nests within-host models of pathogen replication in models for the between-host spread of infectious diseases. Although this provides an elegant approach, it nevertheless suffers from some practical difficulties. In particular, the information required to satisfactorily model the mechanistic details of the within-host dynamics is not often available. Here, we present a theoretical approach that circumvents these difficulties by quantifying the relevant within-host factors in an empirically tractable way. The approach is closely related to quantitative genetic models for function-valued traits, and it also allows for the prediction of general characteristics of disease life history, including the timing of virulence, transmission, and host recovery. In a companion paper, we illustrate the approach by applying it to data from a model system of malaria.     

A popular misapplication of evolutionary modeling to the study of human cooperation

To examine the evolutionary basis of a behavior, an established approach (known as the phenotypic gambit) is to assume that the behavior is controlled by a single allele, the fitness effects of which are derived from a consideration of how the behavior interacts, via life-history, with other ecological factors. Here we contrast successful applications of this approach with several examples of an influential and superficially similar line of research on the evolutionary basis of human cooperation. A key difference is identified: in the latter line of research the focal behavior, cooperation, is abstractly defined in terms of immediate fitness costs and benefits. Selection is then assumed to act on strategies in an iterated social context for which fitness effects can be derived by aggregation of the abstractly defined immediate fitness effects over a lifetime. This approach creates a closed theoretical loop, rendering models incapable of making predictions or providing insight into the origin of human cooperation. We conclude with a discussion of how evolutionary approaches might be appropriately used in the study of human social behavior.     

Social Theory,Ecology and Epistemology: Theoretical Issues in Australian Prehistory

Analysis of certain discussions in Tasmanian prehistory reveals a tacit but strong environmental determinism. This approach, which centres on the notion of cultural adaptation, dominates current research in Australian prehistory. Recent theoretical discussions have, however, shown that the ecological approach is untenable; it is suggested that neo-marxist economic anthropology, emphasizing social rather than ecological relations, provides an alternative. The interpretation of archaeological data in social terms is a problem, but it should be dealt with rather than ignored. A further difficulty arises from the epistemological framework within which most archaeological work has operated: this is simplistic and empiricist. Greater consideration needs to be given to the role of theory in, and the social context of knowledge.     

The Use of Theory in Behavioural Research

A survey of recent publications in behavioural biology suggests that research in this field often lacks a formal approach linking theory and empiricism, which implies that there is scope for improvement. Frequently, hypotheses guiding empirical work are merely based on plausibility arguments, which is not necessarily wrong and may be useful especially at the early stages of an investigation. Behavioural studies based on a theoretical framework usually test qualitative predictions from a general model either with data from natural situations or by experimental scrutiny. Rarely, a quantitative approach is used where a model is parameterized by existing data and therefore generates precise, testable predictions. In general, there is a lack of awareness that much more is to be learnt from a mismatch between predictions and data than from accordance. The latter is prone to cause the ‘pseudo‐proof fallacy’, which is widespread in behavioural ecology. Behavioural physiology, on the other hand, often suffers a lack of proper theoretical models. Much can be gained in both fields if empiricists and theoreticians collaborate more closely towards the ultimate aim – to unravel the mechanisms of behaviour at both, ultimate and proximate levels.     

Bioarcheology has a “health” problem: Conceptualizing “stress” and “health” in bioarcheological research

This article provides a critical historical overview of the stress concept in bioarcheological research and critically evaluates the term “health” in reference to skeletal samples. Stress has a considerable history in 20th century physiological research, and the term has reached a critical capacity of meaning. Stress was operationalized around a series of generalized physiological responses that were associated with a deviation from homeostasis. The term was incorporated into anthropological research during the mid-20th century, and further defined in bioarcheological context around a series of skeletal indicators of physiological disruption and disease. Emphases on stress became a predominate area of research in bioarcheology, and eventually, many studies utilized the terms “health” and “stress” interchangeably as part of a broader, problem-oriented approach to evaluating prehistoric population dynamics. Use of the term “health” in relation to skeletal samples is associated with the intellectual history of bioarcheological research, specifically influences from cultural ecology and processualist archeology and remains problematic for two reasons. First, health represents a comprehensive state of well-being that includes physiological status and individual perception, factors that cannot be readily observed in skeletal samples. Second, the categorization of populations into relative levels of health represents a typological approach, however unintentional. This article advocates for the integration of methodological and theoretical advances from human biology and primatology, while simultaneously incorporating the theoretical constructs associated with social epidemiology into bioarcheological research. Such an approach will significantly increase the applicability of bioarcheological findings to anthropological and evolutionary research, and help realize the goal of a truly relevant bioarcheological paradigm. Am J Phys Anthropol 155:186–191, 2014. © 2014 Wiley Periodicals, Inc.     

Rethinking the theoretical foundation of sociobiology

Current sociobiology is in theoretical disarray, with a diversity of frameworks that are poorly related to each other Part of the problem is a reluctance to revisit the pivotal events that took place during the 1960s, including the rejection of group selection and the development of alternative theoretical frameworks to explain the evolution of cooperative and altruistic behaviors. In this article, we take a "back to basics" approach, explaining what group selection is, why its rejection was regarded as so important, and how it has been revived based on a more careful formulation and subsequent research. Multilevel selection theory (including group selection) provides an elegant theoretical foundation for sociobiology in the future, once its turbulent past is appropriately understood.     

Macro-evolutionary studies of cultural diversity: a review of empirical studies of cultural transmission and cultural adaptation

A growing body of theoretical and empirical research has examined cultural transmission and adaptive cultural behaviour at the individual, within-group level. However, relatively few studies have tried to examine proximate transmission or test ultimate adaptive hypotheses about behavioural or cultural diversity at a between-societies macro-level. In both the history of anthropology and in present-day work, a common approach to examining adaptive behaviour at the macro-level has been through correlating various cultural traits with features of ecology. We discuss some difficulties with simple ecological associations, and then review cultural phylogenetic studies that have attempted to go beyond correlations to understand the underlying cultural evolutionary processes. We conclude with an example of a phylogenetically controlled approach to understanding proximate transmission pathways in Austronesian cultural diversity.     

Studying the effects of virtual biodiversity research infrastructures

The research environment of scholars is increasingly web-based. This makes it urgent to study the effects of moving to the Web on research practices, scholarly output and innovation. We propose a theoretical framework and a methodology to study these effects. In a pilot study, we apply theory and method on an online community in biodiversity research, to demonstrate the feasibility of the approach. We also indicate the practical relevance of this kind of analysis for improving the quality of virtual research environments. In the last section, directions for further research are suggested.     

Taking a tree's perspective on forest fragmentation genetics

Despite longstanding research, how anthropogenic disturbance affects the genetics of tree populations remains poorly understood. Although empirical evidence often conflicts with theoretical expectations, little progress has been made in refining experimental design or in reformulating theoretical hypotheses. Such progress is, however, essential to understand how forest tree species can tolerate anthropogenic disturbance. Further advances in forest fragmentation genetics research will require that processes driving reproduction and recruitment in fragmented populations are assessed from a tree's perspective instead of experimental convenience, using a multidisciplinary approach to explain the spatiotemporal dynamics of gene dispersal. In this opinion article we aim to inspire a new perspective in forest fragmentation genetics research.     

Spain: an extreme case of successful integration of second-generation immigrants with transfers of best practices applicable to other European countries?

This volume presents cutting-edge research on integration and adaptation processes of second-generation immigrant adolescents in Spain that no doubt constitutes an important and timely contribution to the migration-integration debate. Principal findings of the Investigación Longitudinal de la Segunda Generación study indicate a comparatively smooth integration of second-generation immigrant adolescents, arguably best explained by the theoretical hypotheses of neo-assimilationism and segmented assimilation. The major strengths of the study pertain to research design and methodology, and theoretical grounding that enables it to have far-reaching implications for future research on migrant youth in Spain and beyond. The focus here is primarily on questions of transferability of major findings to other European countries, such as Sweden. In essence, the authors’ findings raise a number of important questions regarding the feasibility (or infeasibility) of Spain’s laissez-a-faire approach to integration in countries with contrasting modes of incorporation.     

Testing Genetic Association by Regressing Genotype over Multiple Phenotypes

Complex disorders are typically characterized by multiple phenotypes. Analyzing these phenotypes jointly is expected to be more powerful than dealing with one of them at a time. A recent approach (O''Reilly et al. 2012) is to regress the genotype at a SNP marker on multiple phenotypes and apply the proportional odds model. In the current research, we introduce an explicit expression for the score test statistic and its non-centrality parameter that determines its power. Same simulation studies as those reported in Galesloot et al. (2014) were conducted to assess its performance. We demonstrate by theoretical arguments and simulation studies that, despite its potential usefulness for multiple phenotypes, the proportional odds model method can be less powerful than regular methods for univariate traits. We also introduce an implementation of the proposed score statistic in an R package named iGasso.     

Gender specificity and interdisciplinarity. Methodological-theoretical observations

In public, sex specifity of humans is under a lively discussion, dominated by Social Sciences. It could be observed that between the theoretically involved disciplines natural sciences, social sciences and liberal arts exist very little flow of information and discussion. It was pointed out that sex specifity matters several disciplines because of the complexity of the phenomenon, but the research still lacks epistemological prerequisites to apply to this goal. The contribution makes methodological and theoretical remarks in order to promote an interdisciplinary approach. Obstacles from tradition and organisation of research are mentioned as well as dominating epistemological and theoretical advances.     

Reducing redundancy in invasion ecology by integrating hypotheses into a single theoretical framework

Aim Invasion ecology includes many hypotheses. Empirical evidence suggests that most of these can explain the success of some invaders to some degree in some circumstances. If they all are correct, what does this tell us about invasion? We illustrate the major themes in invasion ecology, and provide an overarching framework that helps organize research and foster links among subfields of invasion ecology and ecology more generally. Location Global. Methods We review and synthesize 29 leading hypotheses in plant invasion ecology. Structured around propagule pressure (P), abiotic characteristics (A) and biotic characteristics (B), with the additional influence of humans (H) on P, A and B (hereon PAB), we show how these hypotheses fit into one paradigm. P is based on the size and frequency of introductions, A incorporates ecosystem invasibility based on physical conditions, and B includes the characteristics of invading species (invasiveness), the recipient community and their interactions. Having justified the PAB framework, we propose a way in which invasion research could progress. Results By highlighting the common ground among hypotheses, we show that invasion ecology is encumbered by theoretical redundancy that can be removed through integration. Using both holistic and incremental approaches, we show how the PAB framework can guide research and quantify the relative importance of different invasion mechanisms. Main conclusions If the prime aim is to identify the main cause of invasion success, we contend that a top‐down approach that focuses on PAB maximizes research efficiency. This approach identifies the most influential factors first, and subsequently narrows the number of potential causal mechanisms. By viewing invasion as a multifaceted process that can be partitioned into major drivers and broken down into a series of sequential steps, invasion theory can be rigorously tested, understanding improved and effective weed management techniques identified.     

Theoretical frameworks for human behavioral endocrinology

How can we best discover the ultimate, evolved functions of endocrine signals within the field of human behavioral endocrinology? Two related premises will guide my proposed answer. First, hormones typically have multiple, simultaneous effects distributed throughout the brain and body, such that in an abstract sense their prototypical function is the coordination of diverse outcomes. Second, coordinated output effects are often evolved, functional responses to specific eliciting conditions that cause increases or decreases in the relevant hormones. If we accept these premises, then a natural way to study hormones is to hypothesize and test how multiple eliciting conditions are mapped into coordinated output effects via hormonal signals. I will call these input–output mappings “theoretical frameworks.” As examples, partial theoretical frameworks for gonadal hormones will be proposed, focusing on the signaling roles of testosterone in men and on estradiol and progesterone in women. Recent research on oxytocin in humans will also be considered as an example in which application of the theoretical framework approach could be especially helpful in making functional sense of the diverse array of findings associated with this hormone. The theoretical framework approach is not especially common in the current literature, with many theories having eschewed explicit consideration of input–output mappings in favor of parsimony-based arguments that attempt to find the one main thing that a hormone does with respect to psychology or behavior. I will argue that these parsimony-based models have many shortcomings, and conclude that the construction and testing of theoretical frameworks provides a better means of discovering the evolved functions of human endocrine signals.     

Imposed mutational meltdown as an antiviral strategy

Following widespread infections of the most recent coronavirus known to infect humans, SARS-CoV-2, attention has turned to potential therapeutic options. With no drug or vaccine yet approved, one focal point of research is to evaluate the potential value of repurposing existing antiviral treatments, with the logical strategy being to identify at least a short-term intervention to prevent within-patient progression, while long-term vaccine strategies unfold. Here, we offer an evolutionary/population-genetic perspective on one approach that may overwhelm the capacity for pathogen defense (i.e., adaptation) – induced mutational meltdown – providing an overview of key concepts, review of previous theoretical and experimental work of relevance, and guidance for future research. Applied with appropriate care, including target specificity, induced mutational meltdown may provide a general, rapidly implemented approach for the within-patient eradication of a wide range of pathogens or other undesirable microorganisms.     

Towards a definition of living systems: A theory of ecological support for behavior

It is proposed that the Darwinian theoretical approach and account of living systems has not yet been clearly given. A first approximation to this is attempted, focussing on behavior in evolving environments. A theoretical terminology is defined emphasizing the mutuality of organism and environment and the existence of biologically theoretical entities.     

中国矿产资源开发区生态补偿研究进展

矿产资源开发区生态补偿是调整利益相关者因资源开采引发的环境利益和经济利益分配不均,并对矿产资源开发造成的外部成本内部化的制度安排。从矿产资源开发区生态补偿的理论研究、生态补偿机制、生态补偿标准,以及多学科交叉研究四方面对我国生态补偿相关研究进行了总结分析。从中发现:我国矿产资源开发区生态补偿仍以政府主导;矿产资源开发区生态补偿机制有待完善,在补偿主体、客体、途径、期限、内容等研究结论仍不明晰;现有补偿主要以经济补偿为主,补偿模式单一、补偿资金不足;生态补偿标准评估方法各有侧重点,尚未形成系统完善的矿产资源开发区生态补偿标准评估方法。今后应加强以下研究:强化生态补偿的理论研究,从市场产权交易和政府监督出发,构建科学生态补偿机制,结合区域自然、社会、经济特征,确定生态补偿标准;科学合理评估矿产资源开发造成的生态服务价值损益;结合生态补偿理论研究,采用多学科交叉分析,根据矿产资源开发阶段,构建矿产资源开发区生态补偿框架体系,明确生态补偿主客体、标准、方式、期限等;提炼矿产资源开发区生态补偿类型与模式,并构建矿产资源开发区生态补偿长效机制。     

Theoretical Maximum Algal Oil Production

Interest in algae as a feedstock for biofuel production has risen in recent years, due to projections that algae can produce lipids (oil) at a rate significantly higher than agriculture-based feedstocks. Current research and development of enclosed photobioreactors for commercial-scale algal oil production is directed towards pushing the upper limit of productivity beyond that of open ponds. So far, most of this development is in a prototype stage, so working production metrics for a commercial-scale algal biofuel system are still unknown, and projections are largely based on small-scale experimental data. Given this research climate, a methodical analysis of a maximum algal oil production rate from a theoretical perspective will be useful to the emerging industry for understanding the upper limits that will bound the production capabilities of new designs. This paper presents a theoretical approach to calculating an absolute upper limit to algal production based on physical laws and assumptions of perfect efficiencies. In addition, it presents a best case approach that represents an optimistic target for production based on realistic efficiencies and is calculated for six global sites. The theoretical maximum was found to be 354,000 L·ha^?1·year^?1 (38,000 gal·ac^?1·year^?1) of unrefined oil, while the best cases examined in this report range from 40,700–53,200 L·ha^?1·year^?1 (4,350–5,700 gal·ac^?1·year^?1) of unrefined oil.