6,522 research outputs found
The Properties of Field Elliptical Galaxies at Intermediate Redshift. I: Empirical Scaling Laws
We present measurements of the Fundamental Plane (FP) parameters (the
effective radius, the mean effective surface brightness, and the central
velocity dispersion) of six field elliptical galaxies at intermediate redshift.
The imaging is taken from the Medium Deep Survey of the Hubble Space Telescope,
while the kinematical data are obtained from long-slit spectroscopy using the
3.6-m ESO telescope. The Fundamental Plane appears well defined in the field
even at redshift 0.3. The data show a shift in the FP zero point with
respect to the local relation, possibly indicating modest evolution, consistent
with the result found for intermediate redshift cluster samples. The FP slopes
derived for our field data, plus other cluster ellipticals at intermediate
redshift taken from the literature, differ from the local ones, but are still
consistent with the interpretation of the FP as a result of homology, of the
virial theorem and of the existence of a relation between luminosity and mass,
. We also derive the surface brightness vs. effective
radius relation for nine galaxies with redshift up to , and data
from the literature; the evolution that can be inferred is consistent with what
is found using the FP.Comment: 17 pages, including 9 figures, MNRAS, accepte
DGNB building certification companion: Sustainability Tool for Assessment, Planning, Learning, and Engaging (STAPLE)
In the construction industry, the popularity of sustainability and its benefits have been on the rise in recent years. Alas, with various building sustainability assessment schemes on the market, there is still no single general method for a comprehensive and inclusive design and building process for sustainable buildings. The literature describes several barriers of entry preventing actors in the industry from seeking sustainability certifications and prioritizing design methods, supporting sustainability in greater numbers. In the newly developed tool, āDGNB building certification companion: Sustainable Tool for Assessment, Planning, Learning, and Engaging (STAPLE)ā, a new Excel-based, interactive, and iterative education focused platform is introduced, intended to engage dialog among stakeholders, building owners, and decision makers, and the assigned group team leaders, based on the five DGNB topics. In order to establish common levels of knowledge, terminology, and understanding for proper interdisciplinary discussions, which would result in suitable and timely decisions, personal and professional development is enabled by imbedded educational documents in multiple formats throughout the tool as plain-language, easily digestible summaries of various topics regarding sustainability and the DGNB certification scheme. The identified barriers are described in the tool followed by a solution to overcome them. The tool, tested at multiple stages of development and moulded by many individuals both within and outside of the sustainable building industry, has shown to achieve the primary goals of assessment of individualās current knowledge, educating through multiple stages and formats, and the inspiring of conversation among team members through a graphical display of opinions. Based on user feedback, the conclusion was that this is a desired product on the market. This new approach is expected to dramatically reduce misunderstandings, conflicts, and mistakes during a sustainable design process, helping the design team plan a project to possibly obtain the highest DGNB score if desired and properly documented
Mangroves as a sustainable coastal defence
Mangroves effectively reduce the height of wind and swell waves over short distances (less than 500 m),\ud
and can reduce storm surge water levels over greater distances (several kilometres of mangroves). Thus mangroves can\ud
contribute to coastal defence strategies. However, their appropriate use depends on a thorough understanding of the\ud
conditions under which they can provide these coastal defence services. Here we present a literature review of this\ud
topic. Small wind and swell waves can be reduced in height by between 50 and 100% over 500 m of mangroves. Wave\ud
reduction largely depends on water depth and vegetation structure and density. However, few measurements are\ud
available for the reduction of bigger waves (> 70 cm in height) in deeper water (> 2 m). Storm surge water levels may\ud
be reduced by between 5 cm and 50 cm per kilometre of mangrove, based on field measurements and validated\ud
numerical models; water level reduction rates depend on the distance from the edge of the mangrove and the forward\ud
speed of the cyclone, amongst other factors. Extreme events may severely damage or destroy mangroves, reducing their\ud
effectiveness as a coastal defence. The use of mangroves in hybrid engineering can reduce flood risk: for example, a\ud
mangrove foreshore in front of a sea wall/dyke will reduce wave impacts on the wall/dyke. The likelihood of waves\ud
overtopping the sea wall or walls being breached is thus reduced, with an associated reduction in sea defence\ud
maintenance costs. Therefore mangroves can contribute to coastal risk reduction, alongside other risk reduction\ud
measures such as sea walls/dykes, early warning systems and evacuation plans. Additionally, mangroves can respond\ud
dynamically to rising sea levels, in some cases maintaining their surface elevation with respect to local sea level; thus\ud
they may act as a sustainable coastal defence in the face of rising sea levels and changing climatic patterns
Massive, Absorption-selected Galaxies at Intermediate Redshifts
The nature of absorption-selected galaxies and their connection to the
general galaxy population have been open issues for more than three decades,
with little information available on their gas properties. Here we show, using
detections of carbon monoxide (CO) emission with the Atacama Large
Millimeter/submillimeter Array (ALMA), that five of seven high-metallicity,
absorption-selected galaxies at intermediate redshifts, ,
have large molecular gas masses, and high molecular gas fractions (. Their modest star
formation rates (SFRs), yr, then
imply long gas depletion timescales, Gyr. The
high-metallicity absorption-selected galaxies at appear
distinct from populations of star-forming galaxies at both ,
during the peak of star formation activity in the Universe, and lower
redshifts, . Their relatively low SFRs, despite the large
molecular gas reservoirs, may indicate a transition in the nature of star
formation at intermediate redshifts, .Comment: 8 pages, 3 figures; accepted for publication in Astrophysical Journal
Letters. Minor changes to match the version in press in ApJ
Asymptotic symmetries in 3d gravity with torsion
We study the nature of asymptotic symmetries in topological 3d gravity with
torsion. After introducing the concept of asymptotically anti-de Sitter
configuration, we find that the canonical realization of the asymptotic
symmetry is characterized by the Virasoro algebra with classical central
charge, the value of which is the same as in general relativity: c=3l/2G.Comment: 25 pages, RevTeX, no figure
Classical-Quantum Coexistence: a `Free Will' Test
Von Neumann's statistical theory of quantum measurement interprets the
instantaneous quantum state and derives instantaneous classical variables. In
realty, quantum states and classical variables coexist and can influence each
other in a time-continuous way. This has been motivating investigations since
longtime in quite different fields from quantum cosmology to optics as well as
in foundations. Different theories (mean-field, Bohm, decoherence, dynamical
collapse, continuous measurement, hybrid dynamics, e.t.c.) emerged for what I
call `coexistence of classical continuum with quantum'. I apply to these
theories a sort of `free will' test to distinguish `tangible' classical
variables useful for causal control from useless ones.Comment: 7pp, based on talk at Conf. on Emergent Quantum Mechanics, Heinz von
Foerster Congress (Vienna University, Nov 11-13, 2011
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