85 research outputs found
Butcher & Oemler Cluster A2111: A Head-on Merger at z = 0.23
We present ROSAT PSPC and HRI observations of A2111, the richest galaxy
cluster photometrically surveyed by Butcher & Oemler (1984). The cluster
contains a distinct comet-shaped X-ray subcomponent, which appears hotter than
the rest of the cluster. The galaxy and X-ray surface brightness distributions
of the cluster show a similarly elongated morphology. These results suggest
that the cluster is undergoing a head-on subcluster merger. This merger may
also be responsible for the high fraction of gas-rich blue galaxies observed in
the cluster. We have further detected a poor cluster along the merging axis and
at a projected distance of about 5 Mpc from A2111.Comment: To be published in MNRAS, 16 pages, plus 13 figures in the GIF or
jpeg format (uuencoded). Black & white postscript files of the figures are
available at http://www.astro.nwu.edu/astro/wqd/paper/a2111
Probing the Evolution of the Galaxy Interaction/Merger Rate Using Collisional Ring Galaxies
We present the results from our program to determine the evolution of the
galaxy interaction/merger rate with redshift using the unique star-forming
characteristics of collisional ring galaxies. We have identified 25 distant
collisional ring galaxy candidates (CRGCs) in a total of 162 deep Hubble Space
Telescope Wide Field/Planetary Camera-2 images obtained from the HST Archives.
Based on measured and estimated redshifts, these 25 CRGCs all lie in the
redshift interval of 0.1 < z < 1. Using the local collisional ring galaxy
volume density and the new ``standard'' cosmology, we find that in order to
account for the number of identified CRGCs in our surveyed fields, the galaxy
interaction/merger rate, parameterized as (1 + z)^m, must increase steeply with
redshift.We determine a minimum value of m = 5.2 0.7, though m could be
as high as 7 or 8. We can rule out a non-evolving (m = 0) and weakly evolving
(m = 1-2) galaxy interaction/merger rate at greater than the 4 sigma level of
confidence.Comment: Accepted in the Astrophysical Journal (11 pages, 4 figures). Higher
resolution version of the figures is available at
http://www.astro.cornell.edu/~vassilis/papers
Author Correction: The future of Blue Carbon science.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
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Thinking outside the gundeck: maritime history, the royal navy, and the outbreak of British civil war, 1625-1642
This is the peer reviewed version of the following article: Thinking outside the gundeck: maritime history, the royal navy and the outbreak of British civil war, 1625â1642, Historical Research, vol. 87 no. 236 (2014), pp. 251-274, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/1468-2281.12049/full. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.Maritime history seems to be suffering an identity crisis, rising in popularity but unsure of its place within historical scholarship and divided in approach. Seafarers, as a consequence, have remained marginal within mainstream history. This article argues that only by integrating the study of maritime topics into wider historical debates can maritime history overcome these doubts, taking as a case study the role of seafarers and the navy in British politics during 1625â42. First examining previous interpretations offered by scholars, largely based on a conception of seafarers as politically and socially isolated from developments ashore, the article then reassesses the available evidence for popular political activity within the maritime community. It argues that seafarers were deeply involved in the political and religious divisions that drove Britain into civil war in 1642; and, more broadly, that scholars should recognize the importance of both local and global approaches to maritime history â that they should think outside the gundeck.Arts and Humanities Research Council (AHRC
Global dataset of soil organic carbon in tidal marshes
Tidal marshes store large amounts of organic carbon in their soils. Field data quantifying soil organic carbon (SOC) stocks provide an important resource for researchers, natural resource managers, and policy-makers working towards the protection, restoration, and valuation of these ecosystems. We collated a global dataset of tidal marsh soil organic carbon (MarSOC) from 99 studies that includes location, soil depth, site name, dry bulk density, SOC, and/or soil organic matter (SOM). The MarSOC dataset includes 17,454 data points from 2,329 unique locations, and 29 countries. We generated a general transfer function for the conversion of SOM to SOC. Using this data we estimated a median (± median absolute deviation) value of 79.2 ± 38.1 Mg SOC haâ1 in the top 30 cm and 231 ± 134 Mg SOC haâ1 in the top 1 m of tidal marsh soils globally. This data can serve as a basis for future work, and may contribute to incorporation of tidal marsh ecosystems into climate change mitigation and adaptation strategies and policies
REV-ERBα Participates in Circadian SREBP Signaling and Bile Acid Homeostasis
The nuclear receptor REV-ERBα shapes the daily activity profile of Sterol Response Element Binding Protein (SREBP) and thereby participates in the circadian control of cholesterol and bile acid synthesis in the liver
Global dataset of soil organic carbon in tidal marshes.
Tidal marshes store large amounts of organic carbon in their soils. Field data quantifying soil organic carbon (SOC) stocks provide an important resource for researchers, natural resource managers, and policy-makers working towards the protection, restoration, and valuation of these ecosystems. We collated a global dataset of tidal marsh soil organic carbon (MarSOC) from 99 studies that includes location, soil depth, site name, dry bulk density, SOC, and/or soil organic matter (SOM). The MarSOC dataset includes 17,454 data points from 2,329 unique locations, and 29 countries. We generated a general transfer function for the conversion of SOM to SOC. Using this data we estimated a median (± median absolute deviation) value of 79.2â±â38.1 Mg SOC ha-1 in the top 30âcm and 231â±â134 Mg SOC ha-1 in the top 1âm of tidal marsh soils globally. This data can serve as a basis for future work, and may contribute to incorporation of tidal marsh ecosystems into climate change mitigation and adaptation strategies and policies
Expert range maps of global mammal distributions harmonised to three taxonomic authorities
AimComprehensive, global information on species' occurrences is an essential biodiversity variable and central to a range of applications in ecology, evolution, biogeography and conservation. Expert range maps often represent a species' only available distributional information and play an increasing role in conservation assessments and macroecology. We provide global range maps for the native ranges of all extant mammal species harmonised to the taxonomy of the Mammal Diversity Database (MDD) mobilised from two sources, the Handbook of the Mammals of the World (HMW) and the Illustrated Checklist of the Mammals of the World (CMW).LocationGlobal.TaxonAll extant mammal species.MethodsRange maps were digitally interpreted, georeferenced, error-checked and subsequently taxonomically aligned between the HMW (6253 species), the CMW (6431 species) and the MDD taxonomies (6362 species).ResultsRange maps can be evaluated and visualised in an online map browser at Map of Life (mol.org) and accessed for individual or batch download for non-commercial use.Main conclusionExpert maps of species' global distributions are limited in their spatial detail and temporal specificity, but form a useful basis for broad-scale characterizations and model-based integration with other data. We provide georeferenced range maps for the native ranges of all extant mammal species as shapefiles, with species-level metadata and source information packaged together in geodatabase format. Across the three taxonomic sources our maps entail, there are 1784 taxonomic name differences compared to the maps currently available on the IUCN Red List website. The expert maps provided here are harmonised to the MDD taxonomic authority and linked to a community of online tools that will enable transparent future updates and version control
Mitochondrial physiology
As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
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