444 research outputs found
Using the full power of the cosmic microwave background to probe axion dark matter
The cosmic microwave background (CMB) places strong constraints on models of
dark matter (DM) that deviate from standard cold DM (CDM), and on initial
conditions beyond the scalar adiabatic mode. Here, the full \textit{Planck}
data set (including temperature, -mode polarisation, and lensing deflection)
is used to test the possibility that some fraction of the DM is composed of
ultralight axions (ULAs). This represents the first use of CMB lensing to test
the ULA model. We find no evidence for a ULA component in the mass range
. We put percent-level constraints on
the ULA contribution to the DM, improving by up to a factor of two compared to
the case with temperature anisotropies alone. Axion DM also provides a
low-energy window onto the high-energy physics of inflation through the
interplay between the vacuum misalignment production of axions and isocurvature
perturbations. We perform the first systematic investigation into the parameter
space of ULA isocurvature, using an accurate isocurvature transfer function at
all values. We precisely identify a "window of co-existence" for
where the data allow,
simultaneously, a contribution of ULAs to the DM, and
contributions of isocurvature and tensors to the CMB power. ULAs in this window
(and \textit{all} lighter ULAs) are shown to be consistent with a large
inflationary Hubble parameter, . The window of
co-existence will be fully probed by proposed CMB-S4 observations with
increased accuracy in the high- lensing power and low- and
-mode polarisation. If ULAs in the window exist, this could allow for two
independent measurements of in the CMB using the axion DM content and
isocurvature, and the tensor contribution to -modes.Comment: 15+8 pages, 12+4 figures, chains available online at
http://www.dunlap.utoronto.ca/~hlozek/AxiChains, code at
https://github.com/dgrin1/axionCAM
Формирование гипохолестеролемии при холестеролопатиях
гипохолестеролемияХОЛЕСТЕРИНхолестеролопати
Sperm competition shapes gene expression and sequence evolution in the ocellated wrasse.
Gene expression differences between males and females often underlie sexually dimorphic phenotypes, and the expression levels of genes that are differentially expressed between the sexes are thought to respond to sexual selection. Most studies on the transcriptomic response to sexual selection treat sexual selection as a single force, but postmating sexual selection in particular is expected to specifically target gonadal tissue. The three male morphs of the ocellated wrasse (Symphodus ocellatus) make it possible to test the role of postmating sexual selection in shaping the gonadal transcriptome. Nesting males hold territories and have the highest reproductive success, yet we detected feminization of their gonadal gene expression compared to satellite males. Satellite males are less brightly coloured and experience more intense sperm competition than nesting males. In line with postmating sexual selection affecting gonadal gene expression, we detected a more masculinized expression profile in satellites. Sneakers are the lowest quality males and showed both de-masculinization and de-feminization of gene expression. We also detected higher rates of gene sequence evolution of male-biased genes compared to unbiased genes, which could at least in part be explained by positive selection. Together, these results reveal the potential for postmating sexual selection to drive higher rates of gene sequence evolution and shape the gonadal transcriptome profile
Structure of axion miniclusters
The peak-patch algorithm is used to identify the densest minicluster seeds in the initial axion density field simulated from string decay. The fate of these dense seeds is found by tracking the subsequent gravitational collapse in cosmological N-body simulations. We find that miniclusters at late times are well described by Navarro-Frenk-White profiles, although for around 80% of simulated miniclusters a single power-law density profile of r−2.9 is an equally good fit due to the unresolved scale radius. Under the assumption that all miniclusters with an unresolved scale radius are described by a power-law plus axion star density profile, we identify a significant number of miniclusters that might be dense enough to give rise to gravitational microlensing if the axion mass is 0.2 meV≲ma≲3 meV. Higher resolution simulations resolving the inner structure and axion star formation are necessary to explore this possibility further
Marine benthic flora and fauna of Gourdon Bay and the Dampier Peninsula in the Kimberley region of North-Western Australia
Surveys undertaken to characterise the marine benthic habitats along the Dampier Peninsula and further south at Gourdon Bay in the Kimberley region of Western Australia were augmented with epibenthic sled sampling of soft and hard bottom habitats. This paper describes the species collected, their biomass and relative abundance for the main groups of marine macrophytes and invertebrates. Five localities were surveyed; Gourdon Bay, Quondong Point to Coulomb Point, Carnot Bay to Beagle Bay, Perpendicular Head and Packer Island. Sampling was limited to fifteen epibenthic dredge operations from a range of habitat types and was designed to target the most common habitat types and to obtain species identifications of the most important species and those which typified different habitat types. Surveys covered a total of 1,350 m 2 of seabed in depths between 11 and 23m. We identified 415 taxa comprising: 1 seagrass, 43 algae, 52 sponges, 30 ascidians, 10 hydroids, 14 scleractinian corals, 52 other cnidarians, 69 crustaceans, 73 molluscs and 71 echinoderms. Despite the limited nature of the sampling, a significant number of new species, range extensions and new records for Western Australia and Australia were recorded. Within the algae, one range extension (Halimeda cf. cuneata f. digitata not previously recorded in Western Australia) and one possible new species of Areschougia were recorded. Two range extensions were present in the ascidians; the solitary ascidian Polycarpa cf. intonata has previously only been recorded in Queensland and Cnemidocarpa cf. radicosa only in temperate Australian waters. There were several range extensions for the crustacea, for example, the sponge crab, Tumidodromia dormia, has only been recorded in Queensland. One species of holothurian of the genus Phyllophorus could not be identified from the literature available and may represent a new species. Similarly, a small species of the echinoid Gymnechinus could possibly be a new species. The collections of hydroids, hard corals, crinoids and molluscs contained no new species or range extensions. There was difficulty in identification of some groups to species level due to the status of the current taxonomic literature (e.g. Cnidaria, Porifera and ascidians) and there may be a number of new species among the material collected. Among the anthozoa, there is at least one new species of Chromonephthea and potentially 10 range extensions to Western Australia. Sinularia cf. acuta and Chromonephthea curvata are both new records for Australia with both previously recorded in Indonesia only. Among the better known taxa (e.g. molluscs, echinoderms, corals), most of the taxa identified to species level have been recorded to occur throughout north-western Australia, however the diversity recorded in this study is less than other parts of the Kimberley and this is almost certainly a result of the small overall area sampled and the single method of collection utilised. The most important species on soft bottom habitats in terms of biomass was the heart urchin Breynia desorii (up to 326 g.m -2). Sponges were the dominant fauna by biomass (up to 620 g.m -2) on hard bottom habitats and biomass was dominated a by a few large cup and massive sponge species (e.g. Pione velans and two unidentified Spheciospongia). The biomass of other filter feeders, especially ascidians (e.g. Aplidium cf. crateriferum), soft corals (e.g. Chromonephthea spp.), gorgonians (e.g. Junceella fragilis and Dichotella gemmacea) was also high, indicating the importance of these groups in characterising hard bottom habitats. Although low in biomass, crinoids such as Comaster multifidus and Comatula pectinata were abundant in samples that included a high biomass of other filter feeders
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Preparation of working calibration and test materials for intra- and interlaboratory surveillance of nuclear materials measurement methods: plutonium nitrate solution
Medium-term environmental changes influence age-specific survival estimates in a salmonid population
Human-induced environmental change is a major stressor on freshwater habitats that has resulted in the population declines of many freshwater species. Ontogenetic shifts in habitat use and associated (st)age-specific requirements mean that impacts of environmental stressors can influence (st)ages in a population differently, and yet relatively few studies of freshwater fish populations account for their detail. We aimed to identify environmental and biotic factors affecting survival estimated for six age-classes of a European grayling population in the River Wylye, UK over a 17-year period. We used a Bayesian age-structured state space model to estimate survival of grayling cohorts between subsequent life stages (eggs to age 5 adults) for 16 annual transitions (2003–2004 to 2018–2019), whilst accounting for imperfect sampling of the population. We quantified the effects of seasonal water flow and temperature, in-stream habitat and prey resource, and potential competitors and predators on survival between subsequent life stages. We used Bayesian variable selection to gauge their relative importance on survival. Grayling abundances declined during the study period (>75% in all age-classes), predominately driven by a loss of mature adults. Changes to seasonal flows negatively influenced their survival: increased days of summer low flow related to decreased survival of subadults and mature adults, and lower winter flows related to reduced recruitment of juveniles from eggs. Higher summer macrophyte cover negatively influenced juvenile and subadult survival and increasing days of high temperature in summer appeared detrimental to juvenile survival. Abundance of brown trout (a potential competitor and predator) did not negatively influence grayling survival. Our results reveal the implications of environmental change on a salmonid population, where recent low summer flows and high temperatures, and below average winter flows, have negatively influenced grayling survival. These conditions appear to be becoming more frequent and persistent in our study river, which is towards the species’ southern range limit, which could render the population vulnerable to climate change. Our study demonstrates how careful analysis of long-term population monitoring and environmental datasets can identify factors affecting (st)age-specific fish population dynamics, and when combined with local expertise, results in realistic mitigation proposals to promote wildlife population persistence
Smartphone Apps for Measuring Human Health and Climate Change Co-Benefits: A Comparison and Quality Rating of Available Apps.
BACKGROUND: Climate change and the burden of noncommunicable diseases are major global challenges. Opportunities exist to investigate health and climate change co-benefits through a shift from motorized to active transport (walking and cycling) and a shift in dietary patterns away from a globalized diet to reduced consumption of meat and energy dense foods. Given the ubiquitous use and proliferation of smartphone apps, an opportunity exists to use this technology to capture individual travel and dietary behavior and the associated impact on the environment and health. OBJECTIVE: The objective of the study is to identify, describe the features, and rate the quality of existing smartphone apps which capture personal travel and dietary behavior and simultaneously estimate the carbon cost and potential health consequences of these actions. METHODS: The Google Play and Apple App Stores were searched between October 19 and November 6, 2015, and a secondary Google search using the apps filter was conducted between August 8 and September 18, 2016. Eligible apps were required to estimate the carbon cost of personal behaviors with the potential to include features to maximize health outcomes. The quality of included apps was assessed by 2 researchers using the Mobile Application Rating Scale (MARS). RESULTS: Out of 7213 results, 40 apps were identified and rated. Multiple travel-related apps were identified, however no apps solely focused on the carbon impact or health consequences of dietary behavior. None of the rated apps provided sufficient information on the health consequences of travel and dietary behavior. Some apps included features to maximize participant engagement and encourage behavior change towards reduced greenhouse gas emissions. Most apps were rated as acceptable quality as determined by the MARS; 1 was of poor quality and 10 apps were of good quality. Interrater reliability of the 2 evaluators was excellent (ICC=0.94, 95% CI 0.87-0.97). CONCLUSIONS: Existing apps capturing travel and dietary behavior and the associated health and environmental impact are of mixed quality. Most apps do not include all desirable features or provide sufficient health information. Further research is needed to determine the potential of smartphone apps to evoke behavior change resulting in climate change and health co-benefits
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