Cardiorespiratory fitness (CRF) refers to the capacity of the circulatory and respiratory systems to supply oxygen to skeletal muscle mitochondria for energy production needed during physical ...activity. CRF is an important marker of physical and mental health and academic achievement in youth. However, only 40% of US youth are currently believed to have healthy CRF. In this statement, we review the physiological principles that determine CRF, the tools that are available to assess CRF, the modifiable and nonmodifiable factors influencing CRF, the association of CRF with markers of health in otherwise healthy youth, and the temporal trends in CRF both in the United States and internationally. Development of a cost-effective CRF measurement process that could readily be incorporated into office visits and in field settings to screen all youth periodically could help identify those at increased risk.
In order to identify the employees who are most likely to be engaged in their work, we conducted a meta-analysis of 114 independent samples (N = 44,224) to provide estimates of the relationship ...between eight personality traits and employee engagement. Results indicated that these personality traits explained 48.10% of the variance in engagement. Supporting energy management theories, relative weights analysis revealed that positive affectivity was by far the strongest predictor of engagement (31.10% of the explained variance; ρ = .62), followed by proactive personality (19.60%; ρ = .49), conscientiousness (14.10%; ρ = .39), and extraversion (12.10%; ρ = .40), whereas neuroticism, negative affectivity, agreeableness, and openness to experience were the least important. We highlight the importance of positive affectivity for engagement and support personality-based selection as a viable means for organizations to build a highly engaged workforce. Implications for using personality assessment to select engaged employees are discussed.
Although several methods have been developed to allow for the analysis of data in the presence of missing values, no clear guide exists to help family researchers in choosing among the many options ...and procedures available. We delineate these options and examine the sensitivity of the findings in a regression model estimated in three random samples from the National Survey of Families and Households (n = 250-2,000). These results, combined with findings from simulation studies, are used to guide answers to a set of 10 common questions asked by researchers when selecting a missing data approach. Modern missing data techniques were found to perform better than traditional ones, but differences between the types of modern approaches had minor effects on the estimates and substantive conclusions. Our findings suggest that the researcher has considerable flexibility in selecting among modern options for handling missing data.
Iron is a central micronutrient needed by all living organisms. Competition for iron in the intestinal tract is essential for the maintenance of indigenous microbial populations and for host health. ...How symbiotic relationships between hosts and native microbes persist during times of iron limitation is unclear. Here, we demonstrate that indigenous bacteria possess an iron-dependent mechanism that inhibits host iron transport and storage. Using a high-throughput screen of microbial metabolites, we found that gut microbiota produce metabolites that suppress hypoxia-inducible factor 2α (HIF-2α) a master transcription factor of intestinal iron absorption and increase the iron-storage protein ferritin, resulting in decreased intestinal iron absorption by the host. We identified 1,3-diaminopropane (DAP) and reuterin as inhibitors of HIF-2α via inhibition of heterodimerization. DAP and reuterin effectively ameliorated systemic iron overload. This work provides evidence of intestine-microbiota metabolic crosstalk that is essential for systemic iron homeostasis.
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•Lactobacillus species sense intestinal iron levels and attenuate host iron absorption•Microbial metabolites DAP and reuterin are novel HIF-2α inhibitors•Gut microbial metabolites regulate intestinal iron storage via ferritin regulation•Gut microbiota can be therapeutically targeted for iron-related disorders
Das et al. show that gut microbiota regulate host iron metabolism. Lactobacillus species are the major bacterial players involved in sensing intestinal iron levels and attenuating host iron absorption. The authors further show that mammalian iron disorders can be therapeutically targeted by modulating microbial species or their metabolites.
This article offers an applied review of key issues and methods for the analysis of longitudinal panel data in the presence of missing values. The authors consider the unique challenges associated ...with attrition (survey dropout), incomplete repeated measures, and unknown observations of time. Using simulated data based on 4 waves of the Marital Instability Over the Life Course Study (n = 2,034), they applied a fixed effect regression model and an event-history analysis with time-varying covariates. They then compared results for analyses with nonimputed missing data and with imputed data both in long and in wide structures. Imputation produced improved estimates in the event-history analysis but only modest improvements in the estimates and standard errors of the fixed effects analysis. Factors responsible for differences in the value of imputation are examined, and recommendations for handling missing values in panel data are presented.
Type VI secretion (T6S) influences the composition of microbial communities by catalyzing the delivery of toxins between adjacent bacterial cells. Here, we demonstrate that a T6S integral membrane ...toxin from Pseudomonas aeruginosa, Tse6, acts on target cells by degrading the universally essential dinucleotides NAD+ and NADP+. Structural analyses of Tse6 show that it resembles mono-ADP-ribosyltransferase proteins, such as diphtheria toxin, with the exception of a unique loop that both excludes proteinaceous ADP-ribose acceptors and contributes to hydrolysis. We find that entry of Tse6 into target cells requires its binding to an essential housekeeping protein, translation elongation factor Tu (EF-Tu). These proteins participate in a larger assembly that additionally directs toxin export and provides chaperone activity. Visualization of this complex by electron microscopy defines the architecture of a toxin-loaded T6S apparatus and provides mechanistic insight into intercellular membrane protein delivery between bacteria.
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•Type VI secretion effector Tse6 acts by depleting bacteria of NAD+ and NADP+•Entry of Tse6 into target cells requires its binding to elongation factor Tu•Tse6 is a membrane protein that requires a chaperone for intercellular transport•EM structures reveal the mechanism for Tse6 deployment to recipient cells
To protect its niche within a microbial community, Pseudomonas secretes a toxin that depletes competing bacterial cells of NAD+ and NADP+. Structures of the toxin and accessory secretory proteins reveal a surprising requirement for the housekeeping protein EF-Tu in toxin delivery and provide mechanistic insight into intercellular protein transport between bacteria.
The Clouds and the Earth's Radiant Energy System (CERES) instruments on board the Terra and Aqua spacecraft continue to provide an unprecedented global climate record of the earth's top-of-atmosphere ...(TOA) energy budget since March 2000. A critical step in determining accurate daily averaged flux involves estimating the flux between CERES Terra or Aqua overpass times. CERES employs the CERES-only (CO) and the CERES geostationary (CG) temporal interpolation methods. The CO method assumes that the cloud properties at the time of the CERES observation remain constant and that it only accounts for changes in albedo with solar zenith angle and diurnal land heating, by assuming a shape for unresolved changes in the diurnal cycle. The CG method enhances the CERES data by explicitly accounting for changes in cloud and radiation between CERES observation times using 3-hourly imager data from five geostationary (GEO) satellites. To maintain calibration traceability, GEO radiances are calibrated against Moderate Resolution Imaging Spectroradiometer (MODIS) and the derived GEO fluxes are normalized to the CERES measurements. While the regional (1 deg latitude x 1 deg longitude) monthly-mean difference between the CG and CO methods can exceed 25 W m(sub -2) over marine stratus and land convection, these regional biases nearly cancel in the global mean. The regional monthly CG shortwave (SW) and longwave (LW) flux uncertainty is reduced by 20%, whereas the daily uncertainty is reduced by 50% and 20%, respectively, over the CO method, based on comparisons with 15-min Geostationary Earth Radiation Budget (GERB) data.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Epigenetic mechanisms have been proposed to play crucial roles in mammalian development, but their precise functions are only partially understood. To investigate epigenetic regulation of embryonic ...development, we differentiated human embryonic stem cells into mesendoderm, neural progenitor cells, trophoblast-like cells, and mesenchymal stem cells and systematically characterized DNA methylation, chromatin modifications, and the transcriptome in each lineage. We found that promoters that are active in early developmental stages tend to be CG rich and mainly engage H3K27me3 upon silencing in nonexpressing lineages. By contrast, promoters for genes expressed preferentially at later stages are often CG poor and primarily employ DNA methylation upon repression. Interestingly, the early developmental regulatory genes are often located in large genomic domains that are generally devoid of DNA methylation in most lineages, which we termed DNA methylation valleys (DMVs). Our results suggest that distinct epigenetic mechanisms regulate early and late stages of ES cell differentiation.
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•Epigenome was mapped in depth for hESCs and four hESC-derived cell types•Lineage-restricted genes and regulatory sequences were identified in these cell types•Distinct mechanisms regulate lineage-restricted genes at early and late stages•Developmental genes tend to reside in large genomic domains devoid of DNA methylation
DNA methylation, histone modifications, and the transcriptome have been mapped in human ES cells and four lineages. The results suggest that early and late stages of ES cell differentiation are regulated by distinct epigenetic mechanisms.
Although transactional leadership is known to be the most common style of leadership in organizations, meta-analytic work has yet to fully uncover the relationship between transactional leadership ...and one of the most focal leadership outcomes: follower performance. Moreover, little is known about the mechanisms that explain why transactional leadership predicts follower performance. To address these gaps, the current article meta-analytically tests a model based on social exchange theory and self-determination theory in which transactional leadership is theorized to affect follower performance sequentially through leader–member exchange (LMX) and psychological empowerment. Specifically, we argue that although some leadership behaviors (e.g., contingent reward) may benefit performance via positive contributions to the leader–follower social exchange, some leadership behaviors (e.g., contingent reward) may simultaneously exhibit negative effects on performance via reduced empowerment. Our results demonstrate that transactional leadership displays both positive and negative indirect effects on follower performance. Furthermore, the pattern of these effects generalizes to two types of performance: task performance and contextual performance. These findings suggest that transactional leadership is a “double-edged sword” when predicting follower performance (e.g., contingent reward fosters LMX but hinders empowerment, whereas management by exception fosters empowerment but hinders LMX). We discuss how leaders can benefit from these findings, including modifying one’s delivery of transactional leadership approaches.
Fathers and daughters participating in an 8-week physical activity program demonstrated post-intervention improvements in physical activity, screen time, sport skill competence and parenting ...practices, which were maintained at 9-month follow-up.
Abstract
Background
Existing strategies to increase girls’ physical activity levels have seen limited success. Fathers may influence their children’s physical activity, but often spend more time with their sons and rarely participate in family-based programs.
Purpose
To test a novel program designed to increase the physical activity levels of fathers and their daughters.
Methods
In a two-arm RCT, 115 fathers (29–53 years) and 153 daughters (4–12 years) were randomized to (i) the “Dads And Daughters Exercising and Empowered” (DADEE) program, or (ii) a wait-list control. The 8-week program included weekly educational and practical sessions plus home tasks. Assessments were at baseline, 2 months (postintervention), and 9 months. The primary outcomes were father–daughter physical activity levels (pedometry). Secondary outcomes included screen-time, daughters’ fundamental movement skill proficiency (FMS: perceived and objective), and fathers’ physical activity parenting practices.
Results
Primary outcome data were obtained from 88% of daughters and 90% of fathers at 9 months. Intention-to-treat analyses revealed favorable group-by-time effects for physical activity in daughters (p = .02, d = 0.4) and fathers (p < .001, d = 0.7) at postintervention, which were maintained at 9 months. At postintervention and follow-up, significant effects (p < .05) were also identified for daughters’ FMS competence (objective: d = 1.1–1.2; perceived: d = 0.4–0.6), a range of fathers’ physical activity parenting practices (d = 0.3–0.8), and screen-time for daughters (d = 0.5–0.8) and fathers (d = 0.4–0.6, postintervention only). Program satisfaction and attendance were very high.
Conclusions
This study provided the first experimental evidence that efforts to increase physical activity behavior in preadolescent girls would benefit from a meaningful engagement of fathers.
Clinical Trial information: Australian New Zealand Clinical Trials Registry: ACTRN12615000022561
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