2,368 research outputs found
Space-based geoengineering: challenges and requirements
The prospect of engineering the Earth's climate (geoengineering) raises a multitude of issues associated with climatology, engineering on macroscopic scales, and indeed the ethics of such ventures. Depending on personal views, such large-scale engineering is either an obvious necessity for the deep future, or yet another example of human conceit. In this article a simple climate model will be used to estimate requirements for engineering the Earth's climate, principally using space-based geoengineering. Active cooling of the climate to mitigate anthropogenic climate change due to a doubling of the carbon dioxide concentration in the Earth's atmosphere is considered. This representative scenario will allow the scale of the engineering challenge to be determined. It will be argued that simple occulting discs at the interior Lagrange point may represent a less complex solution than concepts for highly engineered refracting discs proposed recently. While engineering on macroscopic scales can appear formidable, emerging capabilities may allow such ventures to be seriously considered in the long term. This article is not an exhaustive review of geoengineering, but aims to provide a foretaste of the future opportunities, challenges, and requirements for space-based geoengineering ventures
Properties of HxTaS2
The preparation of Hx TaS2 (0 \u3c x \u3c 0.87) is described. The compounds are only marginally stable at room temperature, slowly evolving H2S and H2 (and possibly Hp in air). Magnetic susceptibility data show that a low temperature transformation in 2H ... TaS2 (at soâąK) is suppressed with the addition of hydrogen, and· at the same time the superconducting transition temperature T c rises from 0.8 to ~4.2âąK at x = 0.11. Heat capacity measurements near this concentration show the superconductivity to be a bulk effect. Finally, by correlation of this data with susceptibility and T c measurements in other intercalation compounds, we suggest that the rise of T c (at low electron transfer) is due to suppression of the low temperature transformation and not due to an excitonic mechanism of superconductivity
Dead cetacean? beach, bloat, float, sink
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Moore, M. J., Mitchell, G. H., Rowles, T. K., & Early, G. Dead cetacean? beach, bloat, float, sink. Frontiers in Marine Science, 7, (2020): 333, doi:10.3389/fmars.2020.00333.Variably buoyant, dead Cetacea may float, or sink and later bloat to refloat if ambient temperature and pressure allow sufficient decomposition gas formation and expansion. Mortality can result from acute or chronic disease, fishery entanglement, vessel collision, noxious noises, or toxicant spills. Investigators often face the daunting task of elucidating a complex series of events, in reverse order, from when and where an animal is found, and to diagnose the cause of death. Various scenarios are possible: an animal could die at sea remaining there or floating ashore, or strand on a beach alive, where it dies and, if cast high enough, remain beached to be scavenged or decompose. An animal that rests low on a beach may refloat again, through increased buoyancy from decomposition gas and favorable tides, currents, and wind. Here we review the factors responsible for the different outcomes, and how to recognize the provenance of a cetacean mortality found beached, or floating at sea. In conclusion, only some carcasses strand, or remain floating. Negatively buoyant animals that die at depth, or on the surface, and sink, may never surface, even after decomposition gas accumulation, as in cold, deep waters gas may fail to adequately reduce the density of a carcass, precluding it from returning to the surface
Cumulative and Differential Effects of Early Child Care and Middle Childhood Out-of-School Time on Adolescent Functioning.
Effects associated with early child care and out-of-school time (OST) during middle childhood were examined in a large sample of U.S. adolescents (N = 958). Both higher quality early child care AND more epochs of organized activities (afterschool programs and extracurricular activities) during middle childhood were linked to higher academic achievement at age 15. Differential associations were found in the behavioral domain. Higher quality early child care was associated with fewer externalizing problems, whereas more hours of early child care was linked to greater impulsivity. More epochs of organized activities was associated with greater social confidence. Relations between early child care and adolescent outcomes were not mediated or moderated by OST arrangements in middle childhood, consistent with independent, additive relations of these nonfamilial settings
Socioeconomic risk, parenting during the preschool years and child health age 6 years
Parentâchild relationships and parenting processes are emerging as potential life course
determinants of health. Parenting is socially patterned and could be one of the factors responsible for
the negative effects of social inequalities on health, both in childhood and adulthood. This study tests
the hypothesis that some of the effect of socioeconomic risk on health in mid childhood is transmitted
via early parenting. Methods: Prospective cohort study in 10 USA communities involving 1041 mother/
child pairs, selected at birth at random with conditional sampling. Exposures: income, maternal
education, maternal age, lone parenthood, ethnic status and objective assessments of mother child
interaction in the first 4 years of life covering warmth, negativity and positive control. Outcomes:
motherâs report of childâs health in general at 6 years. Modelling: multiple regression analyses with
statistical testing of mediational processes. Results: All five indicators of socioeconomic status (SES) were
correlated with all three measures of parenting, such that low SES was associated with poor parenting.
Among the measures of parenting maternal warmth was independently predictive of future health, and
among the socioeconomic variables maternal education, partner presence and âother ethnic groupâ
proved predictive. Measures of parenting significantly mediated the impact of measures of SES on child
health. Conclusions: Parenting mediates some, but not all of the detectable effects of socioeconomic
risk on health in childhood. As part of a package of measures that address other determinants,
interventions to support parenting are likely to make a useful contribution to reducing childhood
inequalities in health
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Infant Attachment Security and the Timing of Puberty: Testing an Evolutionary Hypothesis
Life-history theories of the early programming of human reproductive strategy stipulate that early rearing experience, including that reflected in infant-parent attachment security, regulates psychological, behavioral, and reproductive development. We tested the hypothesis that infant attachment insecurity, compared with infant attachment security, at the age of 15 months predicts earlier pubertal maturation. Focusing on 373 White females enrolled in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, we gathered data from annual physical exams from the ages of 9Âœ years to 15Âœ years and from self-reported age of menarche. Results revealed that individuals who had been insecure infants initiated and completed pubertal development earlier and had an earlier age of menarche compared with individuals who had been secure infants, even after accounting for age of menarche in the infantsâ mothers. These results support a conditional-adaptational view of individual differences in attachment security and raise questions about the biological mechanisms responsible for the attachment effects we discerned
Community structure informs species geographic distributions
This is the author accepted manuscript. The final version is available from Public Library of Science via the DOI in this recordUnderstanding what determines speciesâ geographic distributions is crucial for assessing
global change threats to biodiversity. Measuring limits on distributions is usually, and
necessarily, done with data at large geographic extents and coarse spatial resolution.
However, survival of individuals is determined by processes that happen at small spatial
assembly processes occurring at small scales, and are often available for relatively extensive
areas, so could be useful for explaining species distributions. We demonstrate that Bayesian
Network Inference (BNI) can overcome several challenges to including community structure
into studies of species distributions, despite having been little used to date. We hypothesized
that the relative abundance of coexisting species can improve predictions of species
distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to
incorporate community structure into Species Distribution Models (SDMs), alongside
environmental information. Information on species associations improved SDM predictions
of community structure and species distributions moderately, though for some habitat
specialists the deviance explained increased by up to 15%. We demonstrate that most species
associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a
proxy for local ecological processes. Our study shows that Bayesian Networks, when
interpreted carefully, can be used to include local conditions into measurements of speciesâ
large-scale distributions, and this information can improve the predictions of species
distributionsThis work was funded by FCT Project âQuerComâ (EXPL/AAG-GLO/2488/2013) and the
ERA-Net BiodivERsA project âEC21Câ (BIODIVERSA/0003/2011). A.M.N. was supported
by a Bolsa de Investigacao de Pos-doutoramento (BI_Pos-Doc_UEvora_Catedra Rui
Nabeiro_EXPL_AAG-GLO_2488_2013) and postdoctoral fellowships from the Ministry of
Economy and Competitivity (FPDI-2013-16266 and IJCIâ2015â23498). MGM acknowledges
support by a Marie Curie Intra-European Fellowship within the 7th European Community
Framework Programme (FORECOMM). J. Vicente is supported by POPH/FSE funds and by
National Funds through FCT - Foundation for Science and Technology under the Portuguese
Science Foundation (FCT) through Post-doctoral grant SFRH/BPD/84044/2012. AE has a
postdoctoral contract funded by the project CN-17-022 (Principado de Asturias, Spain). We
are grateful to OneGeology for providing the geological data
The quality of different types of child care at 10 and 18 months. A comparison between types and factors related to quality.
The quality of care offered in four different types of non-parental child care to 307 infants at 10 months old and 331 infants at 18 months old was compared and factors associated with higher quality were identified. Observed quality was lowest in nurseries at each age point, except that at 18 months they offered more learning activities. There were few differences in the observed quality of care by child-minders, grandparents and nannies, although grandparents had somewhat lower safety and health scores and offered children fewer activities. Cost was largely unrelated to quality of care except in child-minding, where higher cost was associated with higher quality. Observed ratios of children to adults had a significant impact on quality of nursery care; the more infants or toddlers each adult had to care for, the lower the quality of the care she gave them. Mothers' overall satisfaction with their child's care was positively associated with its quality for home-based care but not for nursery settings
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