| 1. |
- Luque, R., et al.
(författare)
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A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067
- 2023
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 623:7989, s. 932-937
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Tidskriftsartikel (refereegranskat)abstract
- Planets with radii between that of the Earth and Neptune (hereafter referred to as ‘sub-Neptunes’) are found in close-in orbits around more than half of all Sun-like stars 1,2. However, their composition, formation and evolution remain poorly understood 3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R ⊕ to 2.85R ⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.
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| 2. |
- Ryvkin, Julia, et al.
(författare)
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Failure to mate enhances investment in behaviors that may promote mating reward and impairs the ability to cope with stressors via a subpopulation of Neuropeptide F receptor neurons
- 2024
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Ingår i: PLOS Genetics. - 1553-7390 .- 1553-7404. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Living in dynamic environments such as the social domain, where interaction with others determines the reproductive success of individuals, requires the ability to recognize opportunities to obtain natural rewards and cope with challenges that are associated with achieving them. As such, actions that promote survival and reproduction are reinforced by the brain reward system, whereas coping with the challenges associated with obtaining these rewards is mediated by stress-response pathways, the activation of which can impair health and shorten lifespan. While much research has been devoted to understanding mechanisms underlying the way by which natural rewards are processed by the reward system, less attention has been given to the consequences of failure to obtain a desirable reward. As a model system to study the impact of failure to obtain a natural reward, we used the well-established courtship suppression paradigm in Drosophila melanogaster as means to induce repeated failures to obtain sexual reward in male flies. We discovered that beyond the known reduction in courtship actions caused by interaction with non-receptive females, repeated failures to mate induce a stress response characterized by persistent motivation to obtain the sexual reward, reduced male-male social interaction, and enhanced aggression. This frustrative-like state caused by the conflict between high motivation to obtain sexual reward and the inability to fulfill their mating drive impairs the capacity of rejected males to tolerate stressors such as starvation and oxidative stress. We further show that sensitivity to starvation and enhanced social arousal is mediated by the disinhibition of a small population of neurons that express receptors for the fly homologue of neuropeptide Y. Our findings demonstrate for the first time the existence of social stress in flies and offers a framework to study mechanisms underlying the crosstalk between reward, stress, and reproduction in a simple nervous system that is highly amenable to genetic manipulation. In this study we investigated the effects of failure to obtain reward on the behavioral actions and physiology of male flies. We exposed Drosophila males to repeated sexual encounters with non-receptive females that rejected their courtship efforts and tested the effect on their behavioral responses using a collection of behavioral paradigms. These responses encompass alterations in social behavior, increased aggression, heightened motivation to mate, and a reduced capacity to cope with stressors. We further show that the high motivational state and sensitivity to stress is mediated by the disinhibition of a small population of neurons that express receptors for the fly homologue of neuropeptide Y.
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| 3. |
- Yngfalk, Carl, 1980-
(författare)
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The Constitution of Consumption : Food Labeling and the Politics of Consumerism
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The power dynamics of consumerism is an important aspect of contemporary consumer culture. Within the field of marketing and consumption, consumer culture theory (CCT) tends to understand power in terms of agency, the ability of consumers to emancipate from a market infused by the culture of consumerism. As such, CCT assumes a repressive hypothesis of power, as if consumerism was an external reality from which agentic consumers can escape by acts of dialectical opposition. In contrast, through a Foucauldian approach, the present study emphasizes the productive side of power, arguing that consumerism operates beyond dialectical oppositions to constitute consumption at different levels of scale – at the macro, meso and micro levels. More specifically, through qualitative data generated from official documents and interviews with state agency officials, consumers, and food manufacturers and retailers, the study undertakes a discourse analysis of date labeling in the food market. In accounting for the regulative, organizational and performative dimensions of consumption, the case of date labeling makes it possible to study consumerism at the intersection of the state, business and consumers. The study argues that consumption is constituted through a multiplicity of mundane power struggles that arise in the wake of date labeling. As such, it extends previous approaches by suggesting an extra-dialectical theory of consumer culture. Further, it argues that date labeling reinforces the mind/body dualism of consumerism by privileging cognition and choice at the cost of the human embodiment and sensory perception. It concludes that empowered performativity does not represent a negation of power, but that it emerges as a product of power and the consumerist attempt to constitute effective, predictable, responsible and controlled consumption. However, future research should continue studying the dominant institutional conditions of particular consumption contexts.
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