Social jetlag affects subjective daytime sleepiness in school-aged children and adolescents: A study using the Japanese version of the Pediatric Daytime Sleepiness Scale (PDSS-J)

The aim of this study was to elucidate the level of daytime sleepiness in Japanese school-aged children and adolescents, and to examine associated factors including sleep loss and social jetlag using the Japanese version of the Pediatric Daytime Sleepiness Scale (PDSS-J). After the linguistic validation of the PDSS-J with a multi-step translation methodology, consisting of forward translation, back translation, expert review and cognitive debriefing interviews, we conducted a psychometric validation for 492 students aged 11–16 years (46.7% boys) of public elementary school, junior high school and high school, using the PDSS-J, the Karolinska Sleepiness Scale (KSS), and bedtimes and wake-up times on school days and free days. Internal consistency (Cronbach’s alpha) of the PDSS-J was 0.77, and the test–retest reliability demonstrated by the intraclass coefficient was 0.88. Multivariate logistic regression analysis revealed that both short sleep duration and social jetlag were identified as factors associated with daytime sleepiness, after adjustment for age and sex. PDSS-J scores were significantly higher in the group with large social jetlag with or without sufficient sleep duration than in the group with sufficient sleep duration and small social jetlag. The PDSS-J is an important tool for assessing daytime sleepiness, given its ease of administration and robust psychometric properties. The impact of not only sleep loss but also social jetlag on daytime sleepiness among school-aged children and adolescents must be fully taken into account.     

Sleep quality,chronotype and social jetlag differentially associate with symptoms of attention deficit hyperactivity disorder in adults

Attention deficit hyperactivity disorder (ADHD) is a common neurobehavioural disorder which has been associated with sleep and circadian rhythm disturbances. Numerous studies have linked evening circadian typology with traits and behaviours associated with the disorder, although a precise reason for this relationship has not been clarified. The current study examines ADHD symptoms, impulsivity, cognitive failures, sleep quality and chronotype in a cohort of healthy young adults (N = 396). Results show significant, small magnitude associations between mid-point of sleep on free days, social jetlag (SJL) and ADHD symptoms and impulsivity, although not with cognitive failures. Similarly, sleep quality is also associated with ADHD symptoms and impulsivity. Group-wise approaches show that higher SJL is associated with significantly more ADHD symptoms and impulsivity, and later mid-sleep on free days is also associated with more ADHD symptoms. Stepwise multiple linear regression reveals that, when controlling for age and sex, SJL but not mid-sleep on free days is a significant predictor of ADHD symptoms and impulsivity. These results indicate that SJL may be an important factor to consider when exploring circadian rhythm associations with ADHD symptoms.     

The acheulean handaxe: More like a bird's song than a beatles' tune?

The goal of this paper is to provoke debate about the nature of an iconic artifact—the Acheulean handaxe. Specifically, we want to initiate a conversation about whether or not they are cultural objects. The vast majority of archeologists assume that the behaviors involved in the production of handaxes were acquired by social learning and that handaxes are therefore cultural. We will argue that this assumption is not warranted on the basis of the available evidence and that an alternative hypothesis should be given serious consideration. This alternative hypothesis is that the form of Acheulean handaxes was at least partly under genetic control.     

The evolution of inequality

Understanding how systems of political and economic inequality evolved from relatively egalitarian origins has long been a focus of anthropological inquiry. Many hypotheses have been suggested to link socio‐ecological features with the rise and spread of inequality, and empirical tests of these hypotheses in prehistoric and extant societies are increasing. In this review, we synthesize several streams of theory relevant to understanding the evolutionary origins, spread, and adaptive significance of inequality. We argue that while inequality may be produced by a variety of localized processes, its evolution is fundamentally dependent on the economic defensibility and transmissibility of wealth. Furthermore, these properties of wealth could become persistent drivers of inequality only following a shift to a more stable climate in the Holocene. We conclude by noting several key areas for future empirical research, emphasizing the need for more analyses of contemporary shifts toward institutionalized inequality as well as prehistoric cases.     

The Ontological and Cultural Genesis of Forms of Memorization: Replication of the Experiments of A.N. Leontiev

Information is presented from a replication of the experiments of A.N. Leontiev (1928), and the ontological and cultural genesis of direct and mediated memorization is traced. It was confirmed that each form of memorization develops with a different degree of productivity and in different ways. No confirmation was found for A.N. Leontiev’s postulate that the ontogenesis of memorization is subject to the “parallelogram principle.” The relationship between forms of memorization and the time and nature of mnemic activity is shown. A pronounced decrease was found in the productivity of memorization processes among present-day schoolchildren and undergraduates as compared with the schoolchildren and undergraduates tested by A.N. Leontiev.     

Entamoeba Clone‐Recognition Experiments: Morphometrics,Aggregative Behavior,and Cell‐Signaling Characterization

Studies on clone‐ and kin‐discrimination in protists have proliferated during the past decade. We report clone‐recognition experiments in seven Entamoeba lineages (E. invadens IP‐1, E. invadens VK‐1:NS, E. terrapinae, E. moshkovskii Laredo, E. moshkovskii Snake, E. histolytica HM‐1:IMSS and E. dispar). First, we characterized morphometrically each clone (length, width, and cell‐surface area) and documented how they differed statistically from one another (as per single‐variable or canonical‐discriminant analyses). Second, we demonstrated that amebas themselves could discriminate self (clone) from different (themselves vs. other clones). In mix‐cell‐line cultures between closely‐related (E. invadens IP‐1 vs. E. invadens VK‐1:NS) or distant‐phylogenetic clones (E. terrapinae vs. E. moshkovskii Laredo), amebas consistently aggregated with same‐clone members. Third, we identified six putative cell‐signals secreted by the amebas (RasGap/Ankyrin, coronin‐WD40, actin, protein kinases, heat shock 70, and ubiquitin) and which known functions in Entamoeba spp. included: cell proliferation, cell adhesion, cell movement, and stress‐induced encystation. To our knowledge, this is the first multi‐clone characterization of Entamoeba spp. morphometrics, aggregative behavior, and cell‐signaling secretion in the context of clone‐recognition. Protists allow us to study cell–cell recognition from ecological and evolutionary perspectives. Modern protistan lineages can be central to studies about the origins and evolution of multicellularity.     

Promoting Industrial Symbiosis: Using the Concept of Proximity to Explore Social Network Development

Industrial symbiosis (IS) has been identified as a strategy for promoting industrial sustainability. IS has been defined as the development of close working agreements between industrial and other organizations that, through the innovative reuse, recycling, or sharing of resources, leads to resource efficiency. Key to IS are innovation and social network development. This article critically reviews IS literature and concludes that, to inform proactive strategies for promoting IS, the understanding of the social processes leading to resource innovation needs to be improved. Industrial ecologists generally believe that close geographical proximity and trust are essential to the development of IS. This article argues, however, that there is a need to learn more about the meaning of, need for, and specific role of geographical proximity and trust in IS and, additionally, that other potentially important social factors have remained underexplored. To move IS research forward, this article suggests to engage with research in economic geography on the concept of ‘proximity,’ which draws attention to the ways in which geographical, cognitive, institutional, social, and organizational distances between actors might affect innovation. Arguably, the analytically distinct, but flexible, dimensions of proximity can be useful to explore how and why IS develops. The resulting qualitative knowledge would form a basis for researching whether general patterns for IS development exist and, more important, could inform public and private strategies that indicate which actions could be taken, as well as when and in what way to promote resource synergies and sustainable industrial development.     

Forest biomass energy: assessing atmospheric carbon impacts by discounting future carbon flows

Although forest biomass energy was long assumed to be carbon neutral, many studies show delays between forest biomass carbon emissions and sequestration, with biomass carbon causing climate change damage in the interim. While some models suggest that these primary biomass carbon effects may be mitigated by induced market effects, for example, from landowner decisions to increase afforestation due to higher biomass prices, the delayed carbon sequestration of biomass energy systems still creates considerable scientific debate (i.e., how to assess effects) and policy debate (i.e., how to act given these effects). Forests can be carbon sinks, but their carbon absorption capacity is finite. Filling the sink with fossil fuel carbon thus has a cost, and conversely, harvesting a forest for biomass energy – which depletes the carbon sink – creates potential benefits from carbon sequestration. These values of forest carbon sinks have not generally been considered. Using data from the 2010 Manomet Center for Conservation Sciences ‘Biomass sustainability and carbon policy study’ and a model of forest biomass carbon system dynamics, we investigate how discounting future carbon flows affects the comparison of biomass energy to fossil fuels in Massachusetts, USA. Drawing from established financial valuation metrics, we calculate internal rates of return (IRR) as explicit estimates of the temporal values of forest biomass carbon emissions. Comparing these IRR to typical private discount rates, we find forest biomass energy to be preferred to fossil fuel energy in some applications. We discuss possible rationales for zero and near‐zero social discount rates with respect to carbon emissions, showing that social discount rates depend in part on expectations about how climate change affects future economic growth. With near‐zero discount rates, forest biomass energy is preferred to fossil fuels in all applications studied. Higher IRR biomass energy uses (e.g., thermal applications) are preferred to lower IRR uses (e.g., electricity generation without heat recovery).     

Dynamic changes in host–virus interactions associated with colony founding and social environment in fire ant queens (Solenopsis invicta)

The dynamics of host – parasite interactions can change dramatically over the course of a chronic infection as the internal (physiological) and external (environmental) conditions of the host change. When queens of social insects found a colony, they experience changes in both their physiological state (they develop their ovaries and begin laying eggs) and the social environment (they suddenly stop interacting with the other members of the mother colony), making this an excellent model system for examining how these factors interact with chronic infections. We investigated the dynamics of host – viral interactions in queens of Solenopsis invicta (fire ant) as they transition from mating to colony founding/brood rearing to the emergence of the first workers. We examined these dynamics in naturally infected queens in two different social environments, where queens either founded colonies as individuals or as pairs. We hypothesized that stress associated with colony founding plays an important role in the dynamics of host – parasite interactions. We also hypothesized that different viruses have different modalities of interaction with the host that can be quantified by physiological measures and genomic analysis of gene expression in the host. We found that the two most prevalent viruses, SINV‐1 and SINV‐2, are associated with different fitness costs that are mirrored by different patterns of gene expression in the host. In fact SINV‐2, the virus that imposes the significant reduction of a queen's reproductive output is also associated with larger changes of global gene expression in the host. These results show the complexity of interactions between S. invicta and two viral parasites. Our findings also show that chronic infections by viral parasites in insects are dynamic processes that may pose different challenges in the host, laying the groundwork for interesting ecological and evolutionary considerations.     

Behavioral flexibility in age castes of the antPheidole dentata

Division of labor among size and age classes in social insect colonies is a fundamental aspect of sociality, with such classes typically showing behavioral specialization and being associated with particular tasks for prolonged periods of time (i.e., forming castes). Theoretically, such specialization and division of labor enhance efficiency and, ultimately, reproductive success, and the ratios among members of those castes are hypothesized to be under selection and adaptive. However, our recent field study of the ant Pheidole dentatashowed no correlation between ecological factors which should affect colony growth and those caste ratios but implied flexibility in the association between minor worker age castes and their tasks. In laboratory experiments on behavioral flexibility in minor age castes of P. dentataold workers in colonies without young workers competently perform both old worker (castetypical) and young worker (atypical) tasks, and vice versa. The implications of these results for ergonomie theory are considered.