33,752 research outputs found
COGENT programming manual
COGENT /COmpiler and GENeralized Translator/ programming system is a compiler whose input language enables a description of symbolic and linguistic manipulation algorithms. Primarily for use as a compiler-compiler, it is also applicable to algebraic manipulation, mechanical theorem proving, and heuristic programming
Automatic computation of data-set definitions
Mathematical method for the construction of a computer program data set description from a computer program contains detailed declarative information. Cartesian products and disjoint-union operators are used to yield a series of recursive group equations
Variability in Plio-Pleistocene climates, habitats, and ungulate biomass in southern Africa
Vrba, and deMenocal and Bloemendal have emphasised the importance of climatic change, particularly temperature, in the context of evolution on the African continent within the past 5 million years. There is no doubt that long-term changes in climate would have affected African habitats, which in turn would have affected the distribution and abundance of populations of various mammalian taxa, including ungulates and hominids. In this study we explore relationships between oxygen isotope ratios (as determined from Shackleton's analysis of foraminifera from deep-sea cores), and estimates of ungulate biomass as determined from faunal assemblages from Plio-Pleistocene sites in southern Africa, using an approach outlined previously. We go further to assess temporal variability in ungulate biomass in terms of changes in habitat, gene pools and hominid evolutio
Effects of Australian Economic Activities on Waste Generation and Treatment
Understanding the relationships between the Australian economic system and waste generation from intermediate sectors and households is a prerequisite for planning and implementing waste management strategies at a national scale. Data of waste generation accounts link to those of national economic accounts. However, in Australia, some years’ data are absent and so these links cannot be made. To rectify this data gap, this paper interpolates and extrapolates the Australian input-output table (IOT) of 2010–2011. Waste input-output (WIO) analysis is then used to assess the effects of the Australian economy on waste generation and treatment between 2009–2010 and 2010–2011. Analysis indicated that the result of interpolation was more reasonable than that of extrapolation, and the interpolation of the Australian IOT of 2010–2011 can be applicable. This comparative analysis of the time series data in WIO model has identified that: (1) per million $AUD of output of the Construction sector generated the most amount of direct and total waste during the period; (2) the relationships between the development of Australian economy and waste generation illustrate that the Australian economy is currently a traditional linear economy; (3) the effectiveness of waste-related policies are shown by the growth of the sums of direct and total effects of intermediate sectors on the Recovery sector; and (4) the amount of waste generated by households increased sharply over the two years. The physical flows of waste footprint show details of waste generation and treatment in the Australian economic system. The information provided in this paper is beneficial to formulate tailor-made policies for waste management in Australia
The Angular Momenta of Neutron Stars and Black Holes as a Window on Supernovae
It is now clear that a subset of supernovae display evidence for jets and are
observed as gamma-ray bursts. The angular momentum distribution of massive
stellar endpoints provides a rare means of constraining the nature of the
central engine in core-collapse explosions. Unlike supermassive black holes,
the spin of stellar-mass black holes in X-ray binary systems is little affected
by accretion, and accurately reflects the spin set at birth. A modest number of
stellar-mass black hole angular momenta have now been measured using two
independent X-ray spectroscopic techniques. In contrast, rotation-powered
pulsars spin-down over time, via magnetic braking, but a modest number of natal
spin periods have now been estimated. For both canonical and extreme neutron
star parameters, statistical tests strongly suggest that the angular momentum
distributions of black holes and neutron stars are markedly different. Within
the context of prevalent models for core-collapse supernovae, the angular
momentum distributions are consistent with black holes typically being produced
in GRB-like supernovae with jets, and with neutron stars typically being
produced in supernovae with too little angular momentum to produce jets via
magnetohydrodynamic processes. It is possible that neutron stars are imbued
with high spin initially, and rapidly spun-down shortly after the supernova
event, but the available mechanisms may be inconsistent with some observed
pulsar properties.Comment: ApJ Letters, accepte
Apollo telescope mount: A partial listing of scientific publications, supplement 2
Reports are compilations of bibliographies from the principal investigator groups of the Apollo Telescope Mount (Skylab solar observatory facility) that gathered data from May 28, 1973, to February 8, 1974. The analysis of these data is presently under way and is expected to continue for several years. The publications listed in this report are divided into the following categories: (1) Journal Publications, (2) Journal Publications Submitted, (3) Other Publications, (4) Presentations--National and International Meetings, and (5) Other Presentations. An author index is included together with errata for the first report
Apollo telescope mount: A partial listing of scientific publications and presentations
A compilation of bibliographies from the principal investigator groups of the Apollo Telescope Mount (Skylab solar observatory facility) which gathered data from May 28, 1973, to February 8, 1974 is presented. The analysis of these data is presently under way and is expected to continue for several years. The publications listed are divided into the following categories: (1) Journal Publications, (2) Journal Publications Submitted, (3) Other Publications, (4) Presentations - National International Meetings, and (5) Other Presentations. An author index is also included
Apollo telescope mount. A partial listing of scientific publications and presentations, supplement 1
Compilations of bibliographies from the principal investigator groups of the Apollo Telescope Mount (Skylab solar observatory facility) are presented. The publications listed are divided into the following categories: (1) journal publications, (2) journal publications submitted, (3) other publications, (4) presentations - national and international meetings; and (5) other presentations
A Search for Ionized Gas in the Draco and Ursa Minor Dwarf Spheroidal Galaxies
The Wisconsin H Alpha Mapper has been used to set the first deep upper limits
on the intensity of diffuse H alpha emission from warm ionized gas in the Local
Group dwarf spheroidal galaxies (dSphs) Draco and Ursa Minor. Assuming a
velocity dispersion of 15 km/s for the ionized gas, we set limits for the H
alpha intensity of less or equal to 0.024 Rayleighs and less or equal to 0.021
Rayleighs for the Draco and Ursa Minor dSphs, respectively, averaged over our 1
degree circular beam. Adopting a simple model for the ionized interstellar
medium, these limits translate to upper bounds on the mass of ionized gas of
approximately less than 10% of the stellar mass, or approximately 10 times the
upper limits for the mass of neutral hydrogen. Note that the Draco and Ursa
Minor dSphs could contain substantial amounts of interstellar gas, equivalent
to all of the gas injected by dying stars since the end of their main star
forming episodes more than 8 Gyr in the past, without violating these limits on
the mass of ionized gas.Comment: 10 pages, 2 figures, AASTeX two-column format. Accepted for
publication in The Astrophysical Journa
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