12,887 research outputs found
Low-income homeowners in Britain: descriptive analysis
This report is based on findings from secondary analysis of a range of datasets, including the Family Resources Survey (2002/03 and 1995/96), the British Household Panel Study 1991-2002), the Families and Children Study (1999 and 2002), the Survey of English Housing (2002/03) and the English House Condition Survey 2001).
The study aimed to establish the characteristics and circumstances of low-income homeowners. It also examined the reasons why people become, or cease to be low-income homeowners. This study followed up research by Burrows and Wilcox (2000) that found around half the poor are homeowners.
The research was carried out by the National Institute for Economic and Social Research
Groundbased near-IR observations of the surface of Venus
We present images of the nightside of Venus taken in the near-infrared windows at 1.0, 1.1, 1.18, 1.28, 1.31, and 2.3 microns with the new infrared camera/spectrometer IRIS on the Anglo-Australian Telescope. These data were taken in spectral-mapping mode. This technique involves scanning the telescope perpendicular to the slit, while collecting spectra at successive slit positions across the planet. We produce data cubes with one spectral and two spatial dimensions. Images can be extracted over any wavelength regions. Each image has square pixels of 0.8 inch resolution. We reduced the scattered light from the sunlit crescent in images extracted from each window by subtracting images taken on either side of the window, where the Venus atmosphere is opaque. Unlike the short wavelength windows, which reveal thermal contrasts that originate primarily from the surface and deep atmosphere, the emission in the 2.3 microns window is produced at much higher altitudes (30-40 km). Emission contrasts seen near 2.3 microns are associated with horizontal variations in the cloud optical depths, and have rotation periods of about six days. We detect large contrasts in infrared emission (20-40 percent) across the disc of Venus in the 1.0-, 1.1-, 1.18-, 1.28-, and 1.31-micron images. Contrasts at these wavelengths may be due to a combination of variations in the optical depths of the overlying sulfuric acid clouds and differences in surface emission. Comparison with the 2.3-micron images show that the patterns seen in the 1.28- and 1.31-micron windows are consistent with cloud optical depth variations alone and require no contribution from the surface. However, images at 1.0, 1.1, and 1.8 microns from July 1991 show a dark feature having a contrast that increases with decreasing wavelength. This behavior is contrary to that expected of cloud absorption. Images taken on three successive days in October show another dark feature that is stationary with respect to the surface. These regions of lower emission correspond closely to the high-altitude surface regions of Beta Regio and Aphrodite Terra. The images can potentially reveal the near-infrared emissiveity of the surface of Venus, thereby complementing Magellan radar reflectivity and ground based radio emissivity measurements. The contrast ratio between highlands and plains is much smaller than would be expected for blackbody radiation from the surface along. Unlike at radio wavelengths, where the atmosphere is essentially transparent, at near-infrared wavelengths the atmosphere emits, absorbs, and scatters radiation, and can modify the observed topographically induced contrasts. The additional radiation from the atmosphere reduces the contrast, and further modification would be expected if terrain at different altitudes has different emissivities. A fit to our data therefore requires, and may constrain, a model of the lowest scale height of the atmosphere
A Spitzer Spectrum of the Exoplanet HD 189733b
We report on the measurement of the 7.5-14.7 micron spectrum for the
transiting extrasolar giant planet HD 189733b using the Infrared Spectrograph
on the Spitzer Space Telescope. Though the observations comprise only 12 hours
of telescope time, the continuum is well measured and has a flux ranging from
0.6 mJy to 1.8 mJy over the wavelength range, or 0.49 +/- 0.02% of the flux of
the parent star. The variation in the measured fractional flux is very nearly
flat over the entire wavelength range and shows no indication of significant
absorption by water or methane, in contrast with the predictions of most
atmospheric models. Models with strong day/night differences appear to be
disfavored by the data, suggesting that heat redistribution to the night side
of the planet is highly efficient.Comment: 12 pages, 3 figures, accepted for publication in the Astrophysical
Journal Letter
Near-infrared oxygen airglow from the Venus nightside
Groundbased imaging and spectroscopic observations of Venus reveal intense near-infrared oxygen airglow emission from the upper atmosphere and provide new constraints on the oxygen photochemistry and dynamics near the mesopause (approximately 100 km). Atomic oxygen is produced by the Photolysis of CO2 on the dayside of Venus. These atoms are transported by the general circulation, and eventually recombine to form molecular oxygen. Because this recombination reaction is exothermic, many of these molecules are created in an excited state known as O2(delta-1). The airglow is produced as these molecules emit a photon and return to their ground state. New imaging and spectroscopic observations acquired during the summer and fall of 1991 show unexpected spatial and temporal variations in the O2(delta-1) airglow. The implications of these observations for the composition and general circulation of the upper venusian atmosphere are not yet understood but they provide important new constraints on comprehensive dynamical and chemical models of the upper mesosphere and lower thermosphere of Venus
Options for IIASA's Future Agricultural Project: Preliminary Findings of the Feasibility Study: Start
The feasibility study "Strategies and Tactics for Agriculture Reconstruction and Transformation" was planned to investigate the possibility of a new future agricultural project at IIASA. In order to specify possible options for research in this field and to discuss the NMOS' proposals, a seminar on sustainable agriculture was held in Sopron, Hungary, 2-5 March 1987. In this paper the authors summarize the preliminary findings of the feasibility study, including also ideas raised and discussed during the seminar. A more detailed description of these findings will be available in the Proceedings of the seminar to be published later in 1987
What is the prognosis of postherpetic neuralgia?
Postherpetic neuralgia occurs rarely among patients aged 70 years, 25% had some pain at 3 months, but only 10% had pain at 1 year, and none had severe pain. Only a few patients have pain that persists for years (strength of recommendation: A, based on a well-done prospective cohort study)
Organic Haze as a Biosignature in Anoxic Earth-like Atmospheres
Early Earth may have hosted a biologically-mediated global organic haze
during the Archean eon (3.8-2.5 billion years ago). This haze would have
significantly impacted multiple aspects of our planet, including its potential
for habitability and its spectral appearance. Here, we model worlds with
Archean-like levels of carbon dioxide orbiting the ancient sun and an M4V dwarf
(GJ 876) and show that organic haze formation requires methane fluxes
consistent with estimated Earth-like biological production rates. On planets
with high fluxes of biogenic organic sulfur gases (CS2, OCS, CH3SH, and
CH3SCH3), photochemistry involving these gases can drive haze formation at
lower CH4/CO2 ratios than methane photochemistry alone. For a planet orbiting
the sun, at 30x the modern organic sulfur gas flux, haze forms at a CH4/CO2
ratio 20% lower than at 1x the modern organic sulfur flux. For a planet
orbiting the M4V star, the impact of organic sulfur gases is more pronounced:
at 1x the modern Earth organic sulfur flux, a substantial haze forms at CH4/CO2
~ 0.2, but at 30x the organic sulfur flux, the CH4/CO2 ratio needed to form
haze decreases by a full order of magnitude. Detection of haze at an
anomalously low CH4/CO2 ratio could suggest the influence of these biogenic
sulfur gases, and therefore imply biological activity on an exoplanet. When
these organic sulfur gases are not readily detectable in the spectrum of an
Earth-like exoplanet, the thick organic haze they can help produce creates a
very strong absorption feature at UV-blue wavelengths detectable in reflected
light at a spectral resolution as low as 10. In direct imaging, constraining
CH4 and CO2 concentrations will require higher spectral resolution, and R > 170
is needed to accurately resolve the structure of the CO2 feature at 1.57
{\mu}m, likely, the most accessible CO2 feature on an Archean-like exoplanet.Comment: accepted for publication in Astrobiolog
European Union - Reforms - Hungarian interests. What kind of European Union would we like?
The lecture deals with broad topics. First, it addresses some questions related to the current state of the EU integration regarding institutions and common policies. Second, it discusses the continued importance, the main results and hindering factors related to the Lisbon Programme, with a special emphasis on the educational system in Europe and Hungary. Third, the lecture deals with some possibilities in changing the EU’s rather limited external relation models to more flexible instruments
Is the Pale Blue Dot unique? Optimized photometric bands for identifying Earth-like exoplanets
The next generation of ground and space-based telescopes will image habitable
planets around nearby stars. A growing literature describes how to characterize
such planets with spectroscopy, but less consideration has been given to the
usefulness of planet colors. Here, we investigate whether potentially
Earth-like exoplanets could be identified using UV-visible-to-NIR wavelength
broadband photometry (350-1000 nm). Specifically, we calculate optimal
photometric bins for identifying an exo-Earth and distinguishing it from
uninhabitable planets including both Solar System objects and model exoplanets.
The color of some hypothetical exoplanets - particularly icy terrestrial worlds
with thick atmospheres - is similar to Earth's because of Rayleigh scattering
in the blue region of the spectrum. Nevertheless, subtle features in Earth's
reflectance spectrum appear to be unique. In particular, Earth's reflectance
spectrum has a 'U-shape' unlike all our hypothetical, uninhabitable planets.
This shape is partly biogenic because O2-rich, oxidizing air is transparent to
sunlight, allowing prominent Rayleigh scattering, while ozone absorbs visible
light, creating the bottom of the 'U'. Whether such uniqueness has practical
utility depends on observational noise. If observations are photon limited or
dominated by astrophysical sources (zodiacal light or imperfect starlight
suppression), then the use of broadband visible wavelength photometry to
identify Earth twins has little practical advantage over obtaining detailed
spectra. However, if observations are dominated by dark current then optimized
photometry could greatly assist preliminary characterization. We also calculate
the optimal photometric bins for identifying extrasolar Archean Earths, and
find that the Archean Earth is more difficult to unambiguously identify than a
modern Earth twin.Comment: 10 figures, 38 page
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