The price of play: self-organized infant mortality cycles in chimpanzees.
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ABSTRACT:
SUBMITTER: Kuehl HS
PROVIDER: S-EPMC2426927 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ImportanceRaising the price of cigarettes by increasing taxation has been associated with improved perinatal and child health outcomes. Transnational tobacco companies have sought to undermine tobacco tax policy by adopting pricing strategies that maintain the availability of budget cigarettes.ObjectiveTo assess associations between median cigarette prices, cigarette price differentials, and infant mortality across the European Union.Design, setting, and participantsA longitudinal, ecological study was conducted from January 1, 2004, to December 31, 2014, of infant populations in 23 countries (comprising 276 subnational regions) within the European Union.InterventionsMedian cigarette prices and the differential between these and minimum cigarette prices were obtained from Euromonitor International. Pricing differentials were calculated as the proportions (%) obtained by dividing the difference between median and minimum cigarette price by median price. Prices were adjusted for inflation.Main outcomes and measuresAnnual infant mortality rates. Associations were assessed using linear fixed-effect panel regression models adjusted for smoke-free policies, gross domestic product, unemployment rate, education, maternal age, and underlining temporal trends.ResultsAmong the 53 704 641 live births during the study period, an increase of €1 (US $1.18) per pack in the median cigarette price was associated with a decline of 0.23 deaths per 1000 live births in the same year (95% CI, -0.37 to -0.09) and a decline of 0.16 deaths per 1000 live births the following year (95% CI, -0.30 to -0.03). An increase of 10% in the price differential between median-priced and minimum-priced cigarettes was associated with an increase of 0.07 deaths per 1000 live births (95% CI, 0.01-0.13) the following year. Cigarette price increases across 23 European countries between 2004 and 2014 were associated with 9208 (95% CI, 8601-9814) fewer infant deaths; 3195 (95% CI, 3017-3372) infant deaths could have been avoided had there been no cost differential between the median-priced and minimum-priced cigarettes during this period.Conclusions and relevanceHigher cigarette prices were associated with reduced infant mortality, while increased cigarette price differentials were associated with higher infant mortality in the European Union. Combined with other evidence, this research suggests that legislators should implement tobacco tax and price control measures that eliminate budget cigarettes.
| S-EPMC5710372 | biostudies-literature
Project description:When selecting a resource to exploit, an insect colony must take into account at least two constraints: the resource must be abundant enough to sustain the whole group, but not too large to limit exploitation costs, and risks of conflicts with other colonies. Following recent results on cockroaches and ants, we introduce here a behavioral mechanism that satisfies these two constraints. Individuals simply modulate their probability to switch to another resource as a function of the local density of conspecifics locally detected. As a result, the individuals gather at the smallest resource that can host the whole group, hence reducing competition and exploitation costs while fulfilling the overall group's needs. Our analysis reveals that the group becomes better at discriminating between similar resources as it grows in size. Also, the discrimination mechanism is flexible and the group readily switches to a better suited resource as it appears in the environment. The collective decision emerges through the self-organization of individuals, that is, in absence of any centralized control. It also requires a minimal individual cognitive investment, making the proposed mechanism likely to occur in other social species and suitable for the development of distributed decision making tools.
| S-EPMC3097225 | biostudies-literature
Project description:Sleeping on sofas increases the risk of sudden infant death syndrome and other sleep-related deaths. We sought to describe factors associated with infant deaths on sofas.We analyzed data for infant deaths on sofas from 24 states in 2004 to 2012 in the National Center for the Review and Prevention of Child Deaths Case Reporting System database. Demographic and environmental data for deaths on sofas were compared with data for sleep-related infant deaths in other locations, using bivariate and multivariable, multinomial logistic regression analyses.A total of 1024 deaths on sofas made up 12.9% of sleep-related infant deaths. They were more likely than deaths in other locations to be classified as accidental suffocation or strangulation (adjusted odds ratio [aOR] 1.9; 95% confidence interval [CI], 1.6-2.3) or ill-defined cause of death (aOR 1.2; 95% CI, 1.0-1.5). Infants who died on sofas were less likely to be Hispanic (aOR 0.7; 95% CI, 0.6-0.9) compared with non-Hispanic white infants or to have objects in the environment (aOR 0.6; 95% CI, 0.5-0.7) and more likely to be sharing the surface with another person (aOR 2.4; 95% CI, 1.9-3.0), to be found on the side (aOR 1.9; 95% CI, 1.4-2.4), to be found in a new sleep location (aOR 6.5; 95% CI, 5.2-8.2), and to have had prenatal smoke exposure (aOR 1.4; 95% CI, 1.2-1.6). Data on recent parental alcohol and drug consumption were not available.The sofa is an extremely hazardous sleep surface for infants. Deaths on sofas are associated with surface sharing, being found on the side, changing sleep location, and experiencing prenatal tobacco exposure, which are all risk factors for sudden infant death syndrome and sleep-related deaths.
| S-EPMC4210798 | biostudies-other
Project description:Podosomes are self-organized, dynamic, actin-containing structures that adhere to the extracellular matrix via integrins [1-5]. Yet, it is not clear what regulates podosome dynamics and whether podosomes can function as direct mechanosensors, like focal adhesions [6-9]. We show here that myosin-II proteins form circular structures outside and at the podosome actin ring to regulate podosome dynamics. Inhibiting myosin-II-dependent tension dissipated podosome actin rings before dissipating the myosin-ring structure. As podosome rings changed size or shape, tractions underneath the podosomes were exerted onto the substrate and were abolished when myosin-light-chain activity was inhibited. The magnitudes of tractions were comparable to those generated underneath focal adhesions, and they increased with substrate stiffness. The dynamics of podosomes and of focal adhesions were different. Torsional tractions underneath the podosome rings were generated with rotations of podosome rings in a nonmotile, nonrotating cell, suggesting a unique feature of these circular structures. Stresses applied via integrins at the apical surface directly displaced podosomes near the basal surface. Stress-induced podosome displacements increased nonlinearly with applied stresses. Our results suggest that podosomes are dynamic mechanosensors in which interactions of myosin tension and actin dynamics are crucial for regulating these self-organized structures in living cells.
| S-EPMC2605691 | biostudies-literature
Project description:BackgroundThe cause of autoimmunity, which is unknown, is investigated from a different angle, i.e., the defect in immune 'system', to explain the cause of autoimmunity.Methodology/principal findingsRepeated immunization with antigen causes systemic autoimmunity in mice otherwise not prone to spontaneous autoimmune diseases. Overstimulation of CD4(+) T cells led to the development of autoantibody-inducing CD4(+) T (aiCD4(+) T) cell which had undergone T cell receptor (TCR) revision and was capable of inducing autoantibodies. The aiCD4(+) T cell was induced by de novo TCR revision but not by cross-reaction, and subsequently overstimulated CD8(+) T cells, driving them to become antigen-specific cytotoxic T lymphocytes (CTL). These CTLs could be further matured by antigen cross-presentation, after which they caused autoimmune tissue injury akin to systemic lupus erythematosus (SLE).Conclusions/significanceSystemic autoimmunity appears to be the inevitable consequence of over-stimulating the host's immune 'system' by repeated immunization with antigen, to the levels that surpass system's self-organized criticality.
| S-EPMC2795160 | biostudies-literature
Project description:The termite nest is one of the architectural wonders of the living world, built by the collective action of workers in a colony. Each nest has several characteristic structural motifs that allow for efficient ventilation, cooling, and traversal. We use tomography to quantify the nest architecture of the African termite Apicotermes lamani, consisting of regularly spaced floors connected by scattered linear and helicoidal ramps. To understand how these elaborate structures are built and arranged, we formulate a minimal model for the spatiotemporal evolution of three hydrodynamic fields-mud, termites, and pheromones-linking environmental physics to collective building behavior using simple local rules based on experimental observations. We find that floors and ramps emerge as solutions of the governing equations, with statistics consistent with observations of A. lamani nests. Our study demonstrates how a local self-reinforcing biotectonic scheme is capable of generating an architecture that is simultaneously adaptable and functional, and likely to be relevant for a range of other animal-built structures.
| S-EPMC7865135 | biostudies-literature
Project description:Often members of a group benefit from dividing the group's task into separate components, where each member specializes their role so as to accomplish only one of the components. While this division of labor phenomenon has been observed with respect to both manual and cognitive labor, there is no clear understanding of the cognitive mechanisms allowing for its emergence, especially when there are multiple divisions possible and communication is limited. Indeed, maximization of expected utility often does not differentiate between alternative ways in which individuals could divide labor. We developed an iterative two-person game in which there are multiple ways of dividing labor, but in which it is not possible to explicitly negotiate a division. We implemented the game both as a human experimental task and as a computational model. Our results show that the majority of human dyads can finish the game with an efficient division of labor. Moreover, we fitted our computational model to the behavioral data, which allowed us to explain how the perceived similarity between a player's actions and the task's focal points guided the players' choices from one round to the other, thus bridging the group dynamics and its underlying cognitive process. Potential applications of this model outside cognitive science include the improvement of cooperation in human groups, multi-agent systems, as well as human-robot collaboration.
| S-EPMC8289079 | biostudies-literature
Project description:Turbulence in geophysical flows tends to organize itself so that the mean flow remains close to a stability boundary in parameter space. That characteristic suggests self-organized criticality (SOC), a statistical property that has been identified in a range of complex phenomena including earthquakes, forest fires and solar flares. This note explores the relationship between the properties of forced, sheared, stratified turbulence (as found in oceans, atmospheres and other geophysical fluids) and those of SOC. Self-organization to the critical state is demonstrated in a wide range of cases drawn mostly (but not entirely) from in situ observations of ocean turbulence. Turbulent events in the ocean also exhibit a second characteristic associated with SOC: their sizes follow a power-law distribution indicating self-similarity. These results suggest SOC as a new conceptual foundation for the study of geophysical turbulence, an explanation for the mixing efficiency of ocean turbulence and a potential for cross-fertilization with other areas of geophysics.
| S-EPMC6403305 | biostudies-literature
Project description:Recently evidence has accumulated that many neural networks exhibit self-organized criticality. In this state, activity is similar across temporal scales and this is beneficial with respect to information flow. If subcritical, activity can die out, if supercritical epileptiform patterns may occur. Little is known about how developing networks will reach and stabilize criticality. Here we monitor the development between 13 and 95 days in vitro (DIV) of cortical cell cultures (n = 20) and find four different phases, related to their morphological maturation: An initial low-activity state (?19 DIV) is followed by a supercritical (?20 DIV) and then a subcritical one (?36 DIV) until the network finally reaches stable criticality (?58 DIV). Using network modeling and mathematical analysis we describe the dynamics of the emergent connectivity in such developing systems. Based on physiological observations, the synaptic development in the model is determined by the drive of the neurons to adjust their connectivity for reaching on average firing rate homeostasis. We predict a specific time course for the maturation of inhibition, with strong onset and delayed pruning, and that total synaptic connectivity should be strongly linked to the relative levels of excitation and inhibition. These results demonstrate that the interplay between activity and connectivity guides developing networks into criticality suggesting that this may be a generic and stable state of many networks in vivo and in vitro.
| S-EPMC2996321 | biostudies-literature
Project description:In the living cell, proteins are able to organize space much larger than their dimensions. In return, changes of intracellular space can influence biochemical reactions, allowing cells to sense their size and shape. Despite the possibility to reconstitute protein self-organization with only a few purified components, we still lack knowledge of how geometrical boundaries affect spatiotemporal protein patterns. Following a minimal systems approach, we used purified proteins and photolithographically patterned membranes to study the influence of spatial confinement on the self-organization of the Min system, a spatial regulator of bacterial cytokinesis, in vitro. We found that the emerging protein pattern responds even to the lateral, two-dimensional geometry of the membrane such that, as in the three-dimensional cell, Min protein waves travel along the longest axis of the membrane patch. This shows that for spatial sensing the Min system does not need to be enclosed in a three-dimensional compartment. Using a computational model we quantitatively analyzed our experimental findings and identified persistent binding of MinE to the membrane as requirement for the Min system to sense geometry. Our results give insight into the interplay between geometrical confinement and biochemical patterns emerging from a nonlinear reaction-diffusion system.
| S-EPMC3458403 | biostudies-literature