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- Speakman, John R., et al.
(författare)
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Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure
- 2023
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Ingår i: Nature Metabolism. - : NATURE PORTFOLIO. - 2522-5812. ; 5:4, s. 579-588
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Obesity is caused by a prolonged positive energy balance(1,2). Whether reduced energy expenditure stemming from reduced activity levels contributes is debated(3,4). Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor.
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| 3. |
- Verschut, Thomas Alexander, 1988-
(författare)
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Searching for food in complex environments : Integrating processes at multiple spatial scales
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Resources are often unevenly distributed through the environment, resulting in a challenging task for insects to locate food, mates and oviposition sites. Consequently, there is an ongoing need to unravel how insects rely on behavioural and sensory traits while searching for resources in heterogeneous environments. In the first part of this thesis, I addressed this issue by studying how neighbouring resources can affect the likelihood of insects finding their preferred host resources. These effects of neighbouring resources are commonly referred to as associational effects, and are expected to result from limitations in the sensory physiology of insects. Such limitations constrain the insect’s ability to correctly evaluate resource quality at the different steps involved in insect search behaviour. Furthermore, I determined whether the physiological state of an insect, and sensory experiences made during larval stages, can affect host search behaviour in heterogeneous environments.By comparing the behaviour of Drosophila melanogaster in environments with single and multiple resources, I found that the presence of neighbouring recourses increased the selection rates for attractive resources, while it decreased the selection rates for less attractive resources. These effects are referred to as associational susceptibility and associational resistance respectively. Furthermore, by studying oviposition behaviour, I found that during these small-scale behavioural decisions, associational effects are mainly governed by gustatory mediated selection and less by olfactory mediated selection. The oviposition assay eliminated potential misinterpretations of resource quality along the different steps of search behaviour, hence the results suggested that associational effects rely on distinctive selection behaviour between resource types rather than on sensory constraints.In the second part of this thesis I determined whether natal experiences can be used by insects as sensory shortcuts to find host resources, and whether this leads to better larval performance on those selected host resources. For this purpose, I studied the interactions between the larval parasitoid Asecodes lucens and the oligophagous leaf beetle Galerucella sagittariae. The results showed that the relationship between oviposition preference and larval performance, of both insect species, depends on an interactive effect between the insects’ natal origin and the quality of the different host resources. Moreover, I found that the natal origin was a better predictor for the adult host preference, rather than for larval performance. This suggests that, aside from the actual quality of the host resources, locating any suitable host might be even more limiting for the female’s fitness.
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| 5. |
- Anderson, James E., et al.
(författare)
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A New Approach to Evaluating Trade Policy
- 1991
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper introduces a new measure, the Trade Restrictiveness Index, which measures the restrictiveness of a system of trade protection. The index is a general equilibrium application of the distance function and answers the question: "What uniform set of trade restrictions is equivalent (in welfare terms) to the initial protective structure?" The index is applicable to both tariffs and quotas and allows international and intertemporal comparisons. The index is operational and we provide an empirical example to illustrate its applicability and to show its superiority over commonly used measures.
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| 6. |
- Anderson, Lakin
(författare)
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Tensions in Transdisciplinary Research : A study of a climate research group
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In a time of sustainability predicaments and ‘grand challenges’, transdisciplinarity has been put forward as an approach through which researchers can engage with societal transformation for a better world. This study examines tensions that arise in the on-the-ground efforts of researchers to establish and manage a transdisciplinary research group within a Norwegian university. Tensions have been of interest in both studies of science and studies of organizations. Scholars have inquired into the ways in which tensions between interrelated, divergent demands influence the work of scientific knowledge production and organizational life. Transdisciplinary research groups, centers and institutes are proliferating, yet studies of the tensions and challenges they face at the micro-level remain nascent. Drawing on intermittent fieldwork over a two-year period, this dissertation analyses a local case in which climate and energy researchers took a transdisciplinary approach in establishing a “societally engaged” research group and research center in a social sciences department. Key questions are: which tensions do they encounter? How do they respond to them? The study makes use of concepts on tensions and paradox developed in organization and management studies to inform discussions on challenges in inter- and trans-disciplinary research in practice. The case study identifies, illustrates, and analyses several tensions salient for researchers: between the need for both consolidation and interrelation; between the need to grow and formalise the group while also maintaining its closeness and values; between ideas of researchers’ relationship to societal change as both distant and engaged; and between the need to maintain academic autonomy while providing usefulness to non-academic actors. Various responses to these tensions are identified and explored, including defending against, and actively embracing them. The findings allow for rethinking transdiscipclinary research in practice, with implications for research managers, practitioners, and policy makers.
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| 7. |
- Anderson, Peter, et al.
(författare)
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Utilization of synergies between conservation and inoculation biological control through niche partitioning and selective biodiversity
- 2011
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Modern agricultural practices have led to destruction of semi-natural habitats, ecosystems and ecosystem services, and a decrease in the numbers of natural enemies. Conservation biological control (CBC) is the practice of enhancing natural enemy efficacy through modification of the environment or of existing pesticide practices. An additional way to enhance the control effect of pest insects is to combine the strategy of CBC with inoculation biological control (IBC). IBC is the intentional release of a living organism as a biological control agent with the expectation that it will multiply and control the pest for an extended period, but not permanently. Increased natural enemy diversity in biological control has positive effects when the feeding niches of the natural enemies complement each other. By combining biological control agents separated in niche partitioning in time and space, the effect can be greater than the single compartments. In a previous research project we developed a system where two key pests of cabbage and onion (Delia radicum and D. antiqua, respectively are controlled using 1) crop rotation to disrupt their lifecycles and 2) semi-permanent selective flower- and grass strips to enhance the parasitoid wasp Trybliographa rapae and soil inhabitant generalist predators. The specialist larval parasitoid T. rapae as well as the generalist predator/pupal staphylinid parasitoid Aleochara bipustulata attack both Delia pests and, therefore, are not disrupted by the crop rotation which provides a less disturbed system. In a continuation of this project we are studying the impact of complementary biological control strategies on pest control of Delia spp and interactions between the control agents. We will combine IBC, using entomopathogenic fungi, with CBC of T. rapae and A. bipustulata in a crop rotation system. It is a novel ecologically-based management system that relies on the niche complementarity of natural enemies in time and space. The impact of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae on T. rapae and A. bipustulata regarding intraguild interactions, behaviour and fitness will be investigated. The study further combines knowledge of biological control with studies in chemical ecology, to evaluate the role of chemical signals in ecological and as well as behavioural mechanisms. Other host-parasitoid systems have showed that there is fitness costs involved in developing on infected hosts. This will be evaluated for T. rapae and A. bipustulata by measuring fecundity and offspring number, quality (survival, weight, etc.), development and viability in laboratory cage experiments at different host infection levels. The preliminary results of bioassays regarding choice/no-choice and fitness consequences in T.rapae associated with infected host larvae will be presented and discussed in the context of the agroecosystem
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| 8. |
- Anderson, Rachele, et al.
(författare)
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Modelling of time-varying HRV using locally stationary processes
- 2017
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Ingår i: Abstract book. ; , s. 44-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Estimates of heart rate variability (HRV), and particularly parameters related to high frequency HRV (HF-HRV), are in-creasingly used as a proxy of cardiac parasympathetic nervous system regulation. Reduced HF-HRV is related to attention deficits, depression, various anxiety disorders, long-term work related stress or burnout, and cardiovascular diseases [1,2]. In this work, a stochastic model, known asLocally Stationary Processes, [3], is applied to HRV data sequences from 47 test participants. The model parameters are estimated with a novel inference method and regression using a number of available covariates is used to investigate their correlation with the stochastic model parameters.
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| 9. |
- Anderson, Rachele, et al.
(författare)
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Modelling of time-varying HRV using locally stationary processes
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Estimates of heart rate variability (HRV), and particularly parameters related to high frequency HRV (HF-HRV), are in-creasingly used as a proxy of cardiac parasympathetic nervous system regulation. Reduced HF-HRV is related to attention deficits, depression, various anxiety disorders, long-term work related stress or burnout, and cardiovascular diseases [1,2]. In this work, a stochastic model, known as Locally Stationary Processes, [3], is applied to HRV data sequences from 47 test participants. The model parameters are estimated with a novel inference method and regression using a number of available covariates is used to investigate their correlation with the stochastic model parameters.
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