137 research outputs found
Consumer Attitudes towards Sustainability Attributes on Food Labels
Concerns about climate change and the general status of the environment have increased expectation that food products have sustainability credentials, and that these can be verified. There are significant and increasing pressures in key export markets for information on Greenhouse gas (GHG) intensity of products throughout its life-cycle. How this information is conveyed to consumers is a key issue. Labelling is a common method of communicating certain product attributes to consumers that may influence their choices. In a choice experiment concerning fruit purchase decisions, this study estimates willingness to pay for sustainability attributes by consumers in Japan and the UK. The role of label presentation format is investigated: text only, text and graphical, and graphical only. Results indicate that sustainability attributes influence consumers’ fruit purchase decisions. Reduction of carbon in fruit production is shown to be the least valued out of sustainability attributes considered. Differences are evident between presentation formats and between countries, with increased nutrient content being the most sensitive to format and country while carbon reduction is the most insensitive and almost always valued the least.Willingness to pay, Choice experiment, Food labelling, Sustainability, Cross-country comparison, Agricultural and Food Policy, Consumer/Household Economics, Environmental Economics and Policy, Food Consumption/Nutrition/Food Safety, Q18, Q51, Q56,
Consumer attitudes towards sustainability attributes on food labels
Concerns about climate change and the general status of the environment have increased expectation that food products have sustainability credentials, and that these can be verified. There are significant and increasing pressures in key export markets for information on Greenhouse gas (GHG) intensity of products throughout its life-cycle. How this information is conveyed to consumers is a key issue. Labelling is a common method of communicating certain product attributes to consumers that may influence their choices. In a choice experiment concerning fruit purchase decisions, this study estimates willingness to pay for sustainability attributes by consumers in Japan and the UK. The role of label presentation format is investigated: text only, text and graphical, and graphical only. Results indicate that sustainability attributes influence consumers’ fruit purchase decisions. Reduction of carbon in fruit production is shown to be the least valued out of sustainability attributes considered. Differences are evident between presentation formats and between countries, with increased nutrient content being the most sensitive to format and country while carbon reduction is the most insensitive and almost always valued the least
Labelling sustainability - what consumers want, know and understand
With today’s concerns about the general status of the environment, there is an increasing expectation for products to have sustainability attributes. Labelling is a common method of letting consumers know more about what they have bought. Different consumers react differently towards various attributes on food labels and this may have an effect
on their choices. It is helpful to understand which of the many attributes appeal to consumers and how much they may be willing to pay
Cosmology Using Cluster Internal Velocity Dispersions
We compare the distribution of internal velocity dispersions of galaxy
clusters for an observational sample to those obtained from a set of N-body
simulations of seven COBE-normalised cosmological scenarios: the standard CDM
(SCDM) and a tilted (n=0.85) CDM (TCDM) model, a CHDM model with 25% of massive
neutrinos, two low-density LCDM models with Omega_0=0.3 and 0.5, two open OCDM
models with Omega_0=0.4 and 0.6. Simulated clusters are observed in projection
so as to reproduce the main observational biases and are analysed by applying
the same algorithm for interlopers removal and velocity dispersion estimate as
for the reference observational sample. Velocity dispersions for individual
clusters can be largely affected by observational biases in a model-dependent
way: models in which clusters had less time to virialize show larger
discrepancies between 3D and projected velocity dispersions. From the
comparison with real clusters we find that both SCDM and TCDM largely
overproduce clusters. The CHDM model marginally overproduces clusters and
requires a somewhat larger sigma_8 than a purely CDM model in order to produce
the same cluster abundance. The LCDM model with Omega_0=0.3 agrees with data,
while the open model with Omega_0=0.4 and 0.6 underproduces and marginally
overproduces clusters, respectively.Comment: 28 pages, LaTeX uses Elsevier style file, 7 postscript figures (3
bitmapped to lower res.) included. Submitted to New Astronom
The Color Variability of Quasars
We quantify quasar color-variability using an unprecedented variability
database - ugriz photometry of 9093 quasars from SDSS Stripe 82, observed over
8 years at ~60 epochs each. We confirm previous reports that quasars become
bluer when brightening. We find a redshift dependence of this blueing in a
given set of bands (e.g. g and r), but show that it is the result of the flux
contribution from less-variable or delayed emission lines in the different SDSS
bands at different redshifts. After correcting for this effect, quasar
color-variability is remarkably uniform, and independent not only of redshift,
but also of quasar luminosity and black hole mass. The color variations of
individual quasars, as they vary in brightness on year timescales, are much
more pronounced than the ranges in color seen in samples of quasars across many
orders of magnitude in luminosity. This indicates distinct physical mechanisms
behind quasar variability and the observed range of quasar luminosities at a
given black hole mass - quasar variations cannot be explained by changes in the
mean accretion rate. We do find some dependence of the color variability on the
characteristics of the flux variations themselves, with fast, low-amplitude,
brightness variations producing more color variability. The observed behavior
could arise if quasar variability results from flares or ephemeral hot spots in
an accretion disc.Comment: Accepted for publication in ApJ - in press, 17 pages, 14 figures -
v2: abstract typo corrected & reference clean-u
Selecting Quasars by their Intrinsic Variability
We present a new and simple technique for selecting extensive, complete and
pure quasar samples, based on their intrinsic variability. We parametrize the
single-band variability by a power-law model for the light-curve structure
function, with amplitude A and power-law index gamma. We show that quasars can
be efficiently separated from other non-variable and variable sources by the
location of the individual sources in the A-gamma plane. We use ~60 epochs of
imaging data, taken over ~5 years, from the SDSS stripe 82 (S82) survey, where
extensive spectroscopy provides a reference sample of quasars, to demonstrate
the power of variability as a quasar classifier in multi-epoch surveys. For
UV-excess selected objects, variability performs just as well as the standard
SDSS color selection, identifying quasars with a completeness of 90% and a
purity of 95%. In the redshift range 2.5<z<3, where color selection is known to
be problematic, variability can select quasars with a completeness of 90% and a
purity of 96%. This is a factor of 5-10 times more pure than existing
color-selection of quasars in this redshift range. Selecting objects from a
broad griz color box without u-band information, variability selection in S82
can afford completeness and purity of 92%, despite a factor of 30 more
contaminants than quasars in the color-selected feeder sample. This confirms
that the fraction of quasars hidden in the 'stellar locus' of color-space is
small. To test variability selection in the context of Pan-STARRS 1 (PS1) we
created mock PS1 data by down-sampling the S82 data to just 6 epochs over 3
years. Even with this much sparser time sampling, variability is an
encouragingly efficient classifier. For instance, a 92% pure and 44% complete
quasar candidate sample is attainable from the above -selected catalog.Comment: 16 pages, 9 color figures and 5 tables - v3: Equations corrected and
text updated (see Erratum for details of corrections). Erratum:
http://adsabs.harvard.edu/abs/2010ApJ...721.1941S Original Paper:
http://adsabs.harvard.edu/abs/2010ApJ...714.1194
Constraining the Power Spectrum using Clusters
(Shortened Abstract). We analyze a redshift sample of Abell/ACO clusters and
compare them with numerical simulations based on the truncated Zel'dovich
approximation (TZA), for a list of eleven dark matter (DM) models. For each
model we run several realizations, on which we estimate cosmic variance
effects. We analyse correlation statistics, the probability density function,
and supercluster properties from percolation analysis. As a general result, we
find that the distribution of galaxy clusters provides a constraint only on the
shape of the power spectrum, but not on its amplitude: a shape parameter 0.18 <
\Gamma < 0.25 and an effective spectral index at 20Mpc/h in the range
[-1.1,-0.9] are required by the Abell/ACO data. In order to obtain
complementary constraints on the spectrum amplitude, we consider the cluster
abundance as estimated using the Press--Schechter approach, whose reliability
is explicitly tested against N--body simulations. We conclude that, of the
cosmological models considered here, the only viable models are either Cold+Hot
DM ones with \Omega_\nu = [0.2-0.3], better if shared between two massive
neutrinos, and flat low-density CDM models with \Omega_0 = [0.3-0.5].Comment: 37 pages, Latex file, 9 figures; New Astronomy, in pres
Evolving academic library specialties
The purpose of this review is to examine the shaping of librarianship in the academic context through the literature of career specialties, with Abbott's (1988) system of professions providing an analytic framework. The specialties investigated are systems librarian, electronic resource librarian, digital librarian, institutional repository manager, clinical librarian and informationist, digital curator/research data manager, teaching librarian/information literacy educator, and information and knowledge manager. Piecemeal literature based on job advertisements, surveys, and individual case studies is consolidated to offer a novel perspective on the evolution of the profession. The resilience of the profession's core jurisdiction is apparent despite pressures to erode it. Forays into teaching, and more recently into open access and data management, can be understood as responses to such pressure. The attractions but also the risks of embedded roles and overextended claims become apparent when comparing past and prospective specialties. © 2013 ASIS&T
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