2,641 research outputs found
PERCEIVED HAZARD AND PRODUCT CHOICE: AN APPLICATION TO RECREATIONAL SITE CHOICE
This study improves upon the standard "dummy variable" approach to modeling fish consumption advisories by jointly estimating a "perceived hazard" model and a site choice model. The perceived hazard model overcomes the shortcomings of the dummy variable model, namely that all anglers respond equally to advisories and that all anglers know of and believe the advisories. We find that anglers' perceived hazards associated with consumption advisories do affect product (recreational site) choice. Anglers' perceptions also affect welfare measures, where the benefits of contaminant removal follow a more reasonable pattern than that of the dummy variable approach. The joint perceived hazard/product choice model is applicable to a wide variety of risky choices with which consumers are faced.Resource /Energy Economics and Policy,
Risk Perceptions of Arsenic in Tap Water and Consumption of Bottled Water
The demand for bottled water has increased rapidly over the past decade, but bottled water is extremely costly compared to tap water. The convenience of bottled water surely matters to consumers, but are others factors at work? This manuscript examines whether purchases of bottled water are associated with the perceived risk of tap water. All of the past studies on bottled water consumption have used simple scale measures of perceived risk that do not correspond to risk measures used by risk analysts. We elicit a probability-based measure of risk and find that as perceived risks rise, expenditures for bottled water rise.Environmental Economics and Policy, Risk and Uncertainty, Q25, Q53, I12,
Correlated emission and spin-down variability in radio pulsars
The recent revelation that there are correlated period derivative and pulse
shape changes in pulsars has dramatically changed our understanding of timing
noise as well as the relationship between the radio emission and the properties
of the magnetosphere as a whole. Using Gaussian processes we are able to model
timing and emission variability using a regression technique that imposes no
functional form on the data. We revisit the pulsars first studied by Lyne et
al. (2010). We not only confirm the emission and rotational transitions
revealed therein, but reveal further transitions and periodicities in 8 years
of extended monitoring. We also show that in many of these objects the pulse
profile transitions between two well-defined shapes, coincident with changes to
the period derivative. With a view to the SKA and other telescopes capable of
higher cadence we also study the detection limitations of period derivative
changes.Comment: 4 pages, 2 Figures, Proceedings of IAU Symposium 337 "Pulsar
Astrophysics - The Next 50 Years" held at Jodrell Bank Observatory, UK Sept.
4-8 201
Arabidopsis nucleolar protein database (AtNoPDB)
The Arabidopsis Nucleolar Protein Database (http://bioinf.scri.sari.ac.uk/cgi-bin/atnopdb/home) provides information on 217 proteins identified in a proteomic analysis of nucleoli isolated from Arabidopsis cell culture. The database is organized on the basis of the Arabidopsis gene identifier number. The information provided includes protein description, protein class, whether or not the plant protein has a homologue in the most recent human nucleolar proteome and the results of reciprocal BLAST analysis of the human proteome. In addition, for one-third of the 217 Arabidopsis nucleolar proteins, localization images are available from analysis of full-length cDNAâgreen fluorescent protein (GFP) fusions and the strength of signal in different parts of the cellânucleolus, nucleolus-associated structures, nucleoplasm, nuclear bodies and extra-nuclearâis provided. For each protein, the most likely human and yeast orthologues, where identifiable through BLASTX analysis, are given with links to relevant information sources
Distance dependence of excitation energy transfer between spacer-separated conjugated polymer films
We report a systematic study of the scaling with distance of electronic energy transfer between thin films of conjugated polymers separated by a silica spacer. The energy-transfer kinetics were obtained directly from time-resolved photoluminescence measurements and show a 1/ z3 distance dependence of the transfer rate between the excited donor and the acceptor film for zâ„8 nm. This is consistent with Förster theory; but at shorter separations the energy transfer is slower than predicted and can be explained by the breakdown of the point-dipole approximation at zâŒ5 nm. The results are relevant for organic photovoltaics and light-emitting devices, where energy transfer can provide a means of increasing performance
An In Depth Study into Using EMI Signatures for Appliance Identification
Energy conservation is a key factor towards long term energy sustainability.
Real-time end user energy feedback, using disaggregated electric load
composition, can play a pivotal role in motivating consumers towards energy
conservation. Recent works have explored using high frequency conducted
electromagnetic interference (EMI) on power lines as a single point sensing
parameter for monitoring common home appliances. However, key questions
regarding the reliability and feasibility of using EMI signatures for
non-intrusive load monitoring over multiple appliances across different sensing
paradigms remain unanswered. This work presents some of the key challenges
towards using EMI as a unique and time invariant feature for load
disaggregation. In-depth empirical evaluations of a large number of appliances
in different sensing configurations are carried out, in both laboratory and
real world settings. Insights into the effects of external parameters such as
line impedance, background noise and appliance coupling on the EMI behavior of
an appliance are realized through simulations and measurements. A generic
approach for simulating the EMI behavior of an appliance that can then be used
to do a detailed analysis of real world phenomenology is presented. The
simulation approach is validated with EMI data from a router. Our EMI dataset -
High Frequency EMI Dataset (HFED) is also released
Low-threshold organic laser based on an oligofluorene truxene with low optical losses
A blue-emitting distributed feedback laser based on a star-shaped oligofluorene truxene molecule is presented. The gain, loss, refractive index, and (lack of) anisotropy are measured by amplified spontaneous emission and variable-angle ellipsometry. The waveguide losses are very low for an organic semiconductor gain medium, particularly for a neat film. The results suggest that truxenes are promising for reducing loss, a key parameter in the operation of organic semiconductor lasers. Distributed feedback lasers fabricated from solution by spin-coating show a low lasing threshold of 270 W/cm(2) and broad tunability across 25 nm in the blue part of the spectrum
Genomic analysis reveals multiple mismatches between biological and management units in yellowfin tuna (Thunnus albacares)
The South African (SAF) yellowfin tuna (Thunnus albacares) fishery represents a potential example of misalignment between management units and biological processes. The SAF fishery spans an operational stock with a boundary at 20_E, either side of which fish are considered part of Atlantic or Indian Ocean regional stocks. However, the actual recruitment of fish from Atlantic and Indian Ocean spawning populations into SAF waters is unknown. To address this knowledge gap, genomic analysis (11 101 SNPs) was performed on samples from Atlantic and Indian Ocean spawning sites, including SAF sites spanning the current stock boundary. Outlier loci conferred high discriminatory power to assignment tests and revealed that all SAF fish were assigned to the Indian Ocean population and that no Atlantic Ocean fish appeared in the SAF samples. Additionally, several Indian Ocean migrants were detected at the Atlantic spawning site demonstrating asymmetric dispersal and the occurrence of a mixed-stock fishery in Atlantic waters. This study highlights both the spatial inaccuracy of current stock designations and a misunderstanding of interactions between the underlying biological units, which must be addressed in light of local and global declines of the species. Specifically, the entire SAF fishery must be managed as part of the Indian Ocean stock
Population connectivity of an overexploited coastal fish, Argyrosomus coronus (Sciaenidae), in an ocean-warming hotspot
The West Coast dusky kob Argyrosomus coronus is a commercially exploited fish with a distribution confined to the AngolaâBenguela Frontal Zone (ABFZ) of the southeastern Atlantic Ocean. A previous study revealed that during a recent period of local warming the species extended its distribution into Namibian waters, where it hybridised with the resident and congeneric Argyrosomus inodorus. Environmental changes are a major threat to marine biodiversity and when combined with overfishing have the potential to accelerate the decline of species. However, little is known regarding the evolutionary history and population structure of A. coronus across the ABFZ. We investigated genetic diversity, population structure and historical demographic changes using mtDNA control region sequences and genotypes at six nuclear microsatellite loci, from 180 individuals. A single, genetically homogeneous population was indicated across the distributional range of A. coronus (ÏST = 0.041, FST = 0.000, D = 0.000; p > 0.05). These findings imply that the oceanographic features within the ABFZ do not appear to significantly influence population connectivity in A. coronus, which simplifies management of the species. However, reconstruction of the demographic history points to a close link between the evolutionary history of A. coronus and the environmental characteristics of the ABFZ. This outcome suggests the speciesâ vulnerability to the rapid environmental changes being observed across this region, and highlights a pressing need for transboundary management to mitigate the impacts of climate change in this global hotspot of seawater temperature changes.Keywords: AngolaâBenguela Frontal Zone, climate change, demographic history, marine fisheries, molecular ecology, population structur
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