358 research outputs found

    Substellar and low-mass dwarf identification with near-infrared imaging space observatories

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    AIMS: We aim to evaluate the near-infrared colors of brown dwarfs as observed with four major infrared imaging space observatories: the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), the Euclid mission, and the WFIRST telescope. METHODS: We used the SPLAT SPEX/ISPEX spectroscopic library to map out the colors of the M-, L-, and T-type dwarfs. We have identified which color-color combination is optimal for identifying broad type and which single color is optimal to then identify the subtype (e.g., T0-9). We evaluated each observatory separately as well as the narrow-field (HST and JWST) and wide-field (Euclid and WFIRST) combinations. RESULTS: The Euclid filters perform poorly typing brown dwarfs and WFIRST performs only marginally better, despite a wider selection of filters. WFIRST's W146 and F062 combined with Euclid's Y-band discriminates somewhat better between broad brown dwarf categories. However, subtyping with any combination of Euclid and WFIRST observations remains uncertain due to the lack of medium or narrow-band filters. We argue that a medium band added to the WFIRST filter selection would greatly improve its ability to preselect brown dwarfs its imaging surveys. CONCLUSIONS: The HST filters used in high-redshift searches are close to optimal to identify broad stellar type. However, the addition of F127M to the commonly used broad filter sets would allow for unambiguous subtyping. An improvement over HST is one of two broad and medium filter combinations on JWST: pairing F140M with either F150W or F162M discriminates very well between subtypes

    Ownership-dependent mating tactics of minor males of the beetle Librodor japonicus (Nitidulidae) with intra-sexual dimorphism of mandibles

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    Intra-sexual dimorphism is found in the weapons of many male beetles. Different behavioral tactics to access females between major and minor males, which adopt fighting and alternative tactics, respectively, are thought to maintain the male dimorphism. In these species major males have enlarged weapons that they use in fights with rival males. Minor males also have small weapons in some of these species, and it is unclear why these males possess weapons. We examined the hypothesis that minor males might adopt a fighting tactic when their status was relatively high in comparison with that of other males (e.g., ownership of a territory). We observed the behavioral tactics of major and minor males of the beetle Librodor japonicus, whose males have a dimorphism of their mandibles. Major males fought for resources, whereas minor males adopted two status-dependent tactics, fighting and sneaking, to access females, depending on their ownership of a sap site. We suggest that ownership status-dependent mating tactics in minor males may maintain the intra-sexual dimorphism in this beetle.</p

    Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity

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    Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria

    Inhibition of plasmin-mediated TAFI activation may affect development but not progression of abdominal aortic aneurysms

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    Objective: Thrombin-activatable fibrinolysis inhibitor (TAFI) reduces the breakdown of fibrin clots through its action as an indirect inhibitor of plasmin. Studies in TAFI-deficient mice have implicated a potential role for TAFI in Abdominal Aortic Aneurysm (AAA) disease. The role of TAFI inhibition on AAA formation in adult ApoE-/- mice is unknown. The aim of this paper was to investigate the effects of TAFI inhibition on AAA development and progression. Methods: Using the Angiotensin II model of AAA, male ApoE-/- mice were infused with Angiotensin II 750ng/kg/min with or without a monoclonal antibody inhibitor of plasmin-mediated activation of TAFI, MA-TCK26D6, or a competitive small molecule inhibitor of TAFI, UK-396082. Results: Inhibition of TAFI in the Angiotensin II model resulted in a decrease in the mortality associated with AAA rupture (from 40.0% to 16.6% with MA-TCK26D6 (log-rank Mantel Cox test p = 0.16), and 8.3% with UK-396082 (log-rank Mantel Cox test p = 0.05)). Inhibition of plasmin-mediated TAFI activation reduced the incidence of AAA from 52.4% to 30.0%. However, late treatment with MA-TCK26D6 once AAA were already established had no effect on the progression of AAA in this model. Conclusions: The formation of intra-mural thrombus is responsible for the dissection and early rupture in the angiotensin II model of AAA, and this process can be prevented through inhibition of TAFI. Late treatment with a TAFI inhibitor does not prevent AAA progression. These data may indicate a role for inhibition of plasmin-mediated TAFI activation in the early stages of AAA development, but not in its progression

    Recent developments and strategies in pediatric pharmacology research in the USA

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    Research in pediatric pharmacology has undergone major changes in the last ten years, with an expansion in both publicly and privately funded activities. A number of pharmacokinetics studies and multi-site controlled efficacy trials have been conducted, so that treatment of children and adolescents can now be better informed and evidence-based. Regulatory financial incentives to industry in return for studies on drugs still covered by patent exclusivity have resulted in a substantial increase in pediatric research funded by pharmaceutical companies. In parallel, public funding has supported research on off-patent medications and other clinical important aspects of treatment, such as comparisons between active treatments, including non-pharmacological interventions. With greater interest by industry in pediatric research, the role of government funding agencies has been redefined to avoid duplication and ensure better integration of efforts and utilization of resources. The present review discusses some of the recent developments in pediatric pharmacology with focus on psychiatric medications

    Stable amorphous georgeite as a precursor to a high-activity catalyst .

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    Copper and zinc form an important group of hydroxycarbonate minerals that include zincian malachite, aurichalcite, rosasite and the exceptionally rare and unstable—and hence little known and largely ignored1—georgeite. The first three of these minerals are widely used as catalyst precursors2, 3, 4 for the industrially important methanol-synthesis and low-temperature water–gas shift (LTS) reactions5, 6, 7, with the choice of precursor phase strongly influencing the activity of the final catalyst. The preferred phase2, 3, 8, 9, 10 is usually zincian malachite. This is prepared by a co-precipitation method that involves the transient formation of georgeite11; with few exceptions12 it uses sodium carbonate as the carbonate source, but this also introduces sodium ions—a potential catalyst poison. Here we show that supercritical antisolvent (SAS) precipitation using carbon dioxide (refs 13, 14), a process that exploits the high diffusion rates and solvation power of supercritical carbon dioxide to rapidly expand and supersaturate solutions, can be used to prepare copper/zinc hydroxycarbonate precursors with low sodium content. These include stable georgeite, which we find to be a precursor to highly active methanol-synthesis and superior LTS catalysts. Our findings highlight the value of advanced synthesis methods in accessing unusual mineral phases, and show that there is room for exploring improvements to established industrial catalysts

    Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH

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    Coordinate and redox interactions of epinephrine (Epi) with iron at physiological pH are essential for understanding two very different phenomena - the detrimental effects of chronic stress on the cardiovascular system and the cross-linking of catecholamine-rich biopolymers and frameworks. Here we show that Epi and Fe3+ form stable high-spin complexes in the 1:1 or 3:1 stoichiometry, depending on the Epi/Fe3+ concentration ratio (low or high). Oxygen atoms on the catechol ring represent the sites of coordinate bond formation within physiologically relevant bidentate 1:1 complex. Redox properties of Epi are slightly impacted by Fe3+. On the other hand, Epi and Fe2+ form a complex that acts as a strong reducing agent, which leads to the production of hydrogen peroxide via O-2 reduction, and to a facilitated formation of the Epi-Fe3+ complexes. Epi is not oxidized in this process, i.e. Fe2+ is not an electron shuttle, but the electron donor. Epi-catalyzed oxidation of Fe2+ represents a plausible chemical basis of stress-related damage to heart cells. In addition, our results support the previous findings on the interactions of catecholamine moieties in polymers with iron and provide a novel strategy for improving the efficiency of cross-linking.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3040

    Mir-132/212 is required for maturation of binocular matching of orientation preference and depth perception

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    MicroRNAs (miRNAs) are known to mediate post-transcriptional gene regulation, but their role in postnatal brain development is still poorly explored. We show that the expression of many miRNAs is dramatically regulated during functional maturation of the mouse visual cortex with miR-132/212 family being one of the top upregulated miRNAs. Age-downregulated transcripts are significantly enriched in miR-132/miR-212 putative targets and in genes upregulated in miR-132/212 null mice. At a functional level, miR-132/212 deletion affects development of receptive fields of cortical neurons determining a specific impairment of binocular matching of orientation preference, but leaving orientation and direction selectivity unaltered. This deficit is associated with reduced depth perception in the visual cliff test. Deletion of miR-132/212 from forebrain excitatory neurons replicates the binocular matching deficits. Thus, miR-132/212 family shapes the age-dependent transcriptome of the visual cortex during a specific developmental window resulting in maturation of binocular cortical cells and depth perception

    Wave-emplaced boulders: implications for development of "prime real estate" seafront, North Coast Jamaica

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s10064-013-0517-0Jamaica has a long history of damage to the built environment in coastal areas due to storm surge and tsunami. However, there is limited scientific data to aid the establishment of minimal setback distances and to inform mitigation strategies. Developers of coastal area require cost-effective methods to guide their decisions and to develop mitigation strategies to reduce the potential risk posed to development. This paper explores the use of wave-emplaced boulders to determine the wave heights from historical storm surge/tsunami on the North Coast of Jamaica. As most of the study area was undeveloped priory to 1960, there are limited historical written records of storm surges and/or tsunami impact for this specific site. This research undertook geomorphic mapping of the proposed study area to determine the presence, location, spatial distribution, size, density and volume of wave emplaced boulders along a 2-km stretch of coastline earmarked for development. Based on the wave-emplaced boulders mapped, it was possible to determine the approximate wave heights associated with storms and/or tsunami required to deposit them. The implications for development are discussed. The study of wave-emplaced boulders has provided a rapid and cost-effective method to determine minimal setback distance and the approximate height of waves associated with storms and/or tsunami. The technique developed may be transferable to other areas of coastline earmarked for development along the Jamaican coastlin
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