3,772 research outputs found
Andrew Silke, et al., (edited by Andrew Silke). The psychology of counter-terrorism. Routledge: Oxon UK, 2011. pp. 202. £21.98. ISBN: 978-0-415-55840-2 [Book review]
Reviewed by Robert W. Hand, University of Aberdeen.Publisher PD
Uppercase and lowercase computer printout increases readability
Print chain of 120 characters facilitates production of computer printout in both uppercase and lowercase characters. Although the output speed is reduced, the use of the print chain increases the computer printout readability
Impact of including pre-defined object on high resolution assessments
Many simulation teams create models of empty buildings e.g. without the thermophysical and visual artefacts which are observed in the built environment or with highly abstract representations. This paper explores the impact of including explicit representations of furniture and fittings on multi-domain assessments vis-à-vis environmental control response, support for comfort and visual assessments and model clarity. Typically increasing model resolution is a tedious process and added detail if included, may not be fully utilised. The concept of pre-defined entities, which include visual form, explicit thermophysical composition, IESNA light distributions and mass flow attributes has been introduced in ESP-r. ESP-r facilities for calculating view-factors and insolation distributions have been updated to include this extended data model. Issues related to creating and managing such entities is discussed and the impacts quantified via case studies
The effect of 3-indoleacetic acid on the response of Lactobacillus arabinosus 17-5 to nicotinamide
Lactobacillus arabinosus 17-5 has been widely used as an assay organism for nicotinic acid (NA) since the development of the method by Snell and Wright (1). Although it has been realized that other substances present in tissue extracts may interfere with the bioassay, the nature of such substances has not been elucidated.
During an investigation of tryptophan metabolism in the pea plant, we studied the possible conversion of this compound to nicotinic acid, since such a transformation has been demonstrated to occur in numerous organisms (2-4). The method involved infiltration of tissue with large quantities of tryptophan and subsequent bioassay for nicotinic acid with Lactobacillus arabinosus 17-5. Certain anomalous results led us to believe that other metabolites of tryptophan were interfering with the assay. Because 3-indoleacetic acid (IAA) is a known plant metabolite of tryptophan (5), we tested it for possible interference with the assay, and, as described below, found that such interference may occur under certain circumstances
Contrasting the capabilities of building energy performance simulation programs
For the past 50 years, a wide variety of building energy simulation programs have been developed, enhanced and are in use throughout the building energy community. This paper is an overview of a report, which provides up-to-date comparison of the features and capabilities of twenty major building energy simulation programs. The comparison is based on information provided by the program developers in the following categories: general modeling features; zone loads; building envelope and daylighting and solar; infiltration, ventilation and multizone airflow; renewable energy systems; electrical systems and equipment; HVAC systems; HVAC equipment; environmental emissions; economic evaluation; climate data availability, results reporting; validation; and user interface, links to other programs, and availability
The Mid-IR Spectral Effects of Darkening Agents and Porosity on the Silicate Surface Features of Airless Bodies
We systematically measured the mid-IR spectra of different mixtures of three silicates (antigorite, lizardite, and pure silica) with varying effective porosities and amounts of darkening agent (iron oxide and carbon). These spectra have broad implications for interpretation of current and future mission data for airless bodies, as well as for testing the capabilities of new instruments. Serpentines, such as antigorite and lizardite, are common to airless surfaces, and their mid-IR spectra in the presence of darkening agents and different surface porosities would be typical for those measured by spacecraft. Silica has only been measured in the plumes of Enceladus and presents exciting possibilities for other Saturn-system surfaces due to long range transport of E-ring material. Results show that the addition of the IR-transparent salt, KBr, to simulate surface porosity affected silicate spectra in ways that were not predictable from linear mixing models. The strengthening of silicate bands with increasing pore space, even when only trace amounts of KBr were added, indicates that spectral features of porous surfaces are more detectable in the mid-IR. Combining iron oxide with the pure silicates seemed to flatten most of the silicate features, but strengthened the reststrahlen band of the silica. Incorporating carbon with the silicates weakened all silicate features, but the silica bands were more resistant to being diminished, indicating silica may be more detectable in the mid-IR than the serpentines. We show how incorporating darkening agents and porosity provides a more complete explanation of the mid-IR spectral features previously reported on worlds such as Iapetus
Exciting dark matter in the galactic center
We reconsider the proposal of excited dark matter (DM) as an explanation for
excess 511 keV gamma rays from positrons in the galactic center. We
quantitatively compute the cross section for DM annihilation to nearby excited
states, mediated by exchange of a new light gauge boson with off-diagonal
couplings to the DM states. In models where both excited states must be heavy
enough to decay into e^+ e^- and the ground state, the predicted rate of
positron production is never large enough to agree with observations, unless
one makes extreme assumptions about the local circular velocity in the Milky
Way, or alternatively if there exists a metastable population of DM states
which can be excited through a mass gap of less than 650 keV, before decaying
into electrons and positrons.Comment: Dedicated to the memory of Lev Kofman; 16 pages, 9 figures; v3 added
refs, minor changes, accepted to PR
Follow the Oxygen: Comparative Histories of Planetary Oxygenation and Opportunities for Aerobic Life
Aerobic respiration—the reduction of molecular oxygen (O_2) coupled to the oxidation of reduced compounds such as organic carbon, ferrous iron, reduced sulfur compounds, or molecular hydrogen while conserving energy to drive cellular processes—is the most widespread and bioenergetically favorable metabolism on Earth today. Aerobic respiration is essential for the development of complex multicellular life; thus the presence of abundant O_2 is an important metric for planetary habitability. O_2 on Earth is supplied by oxygenic photosynthesis, but it is becoming more widely understood that abiotic processes may supply meaningful amounts of O_2 on other worlds. The modern atmosphere and rock record of Mars suggest a history of relatively high O2 as a result of photochemical processes, potentially overlapping with the range of O_2 concentrations used by biology. Europa may have accumulated high O_2 concentrations in its subsurface ocean due to the radiolysis of water ice at its surface. Recent modeling efforts suggest that coexisting water and O2 may be common on exoplanets, with confirmation from measurements of exoplanet atmospheres potentially coming soon. In all these cases, O_2 accumulates through abiotic processes—independent of water-oxidizing photosynthesis. We hypothesize that abiogenic O_2 may enhance the habitability of some planetary environments, allowing highly energetic aerobic respiration and potentially even the development of complex multicellular life which depends on it, without the need to first evolve oxygenic photosynthesis. This hypothesis is testable with further exploration and life-detection efforts on O_2-rich worlds such as Mars and Europa, and comparison to O_2-poor worlds such as Enceladus. This hypothesis further suggests a new dimension to planetary habitability: “Follow the Oxygen,” in which environments with opportunities for energy-rich metabolisms such as aerobic respiration are preferentially targeted for investigation and life detection
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