4,085 research outputs found
Wind Turbines and Coastal Recreation Demand
We examine the impact of coastal wind turbines on coastal tourism and recreation for residents of the northern CAMA counties in North Carolina. A combination of telephone and web survey data are used to assess the impact of coastal wind farms on trip behavior and site choice. Most of the respondents to our telephone survey claim to support offshore wind energy development, and independent survey data suggest that the observed levels of support may be indicative of the broader population in this region. Overall, we find very little impact of coastal wind turbines on aggregate recreational visitation; loss in consumer surplus associated with wide spread wind development in the coastal zone is insignificant at 55 per household. On average, we find no evidence of aversion to wind farms 4 miles out in the ocean, or for wind farms located in coastal estuaries. For all wind farm scenarios, we find evidence of preference heterogeneity– some respondents find this appealing while others find it aversive. Key Words: Recreation demand, tourism, renewable energy
Going Home: Evacuation-Migration Decisions of Hurricane Katrina Survivors
In the wake of Hurricane Katrina, many evacuees from the Gulf region began the difficult process of deciding whether to rebuild or restart elsewhere. We examine pre-Katrina Gulf residents’ decision to return to the post-disaster Gulf region—which we call the “return migration” decision. We estimate two separate return migration models, first utilizing data from a mail survey of individuals in the affected region and then focusing on self-administered questionnaires of evacuees in Houston. Our results indicate that return migration can be affected by household income; age; education level; employment, marital and home ownership status; but the results depend upon the population under consideration. We find no impact of “connection to place” on the return migration decision. While the impact of income is relatively small, we find that the real wage differential between home and host region influences the likelihood of return. Larger implicit costs, in terms of foregone wages for returning, induce a lower likelihood of return. Exploiting this difference at the individual level, we are able to produce estimates of willingness to pay to return home. Average WTP to return home for a sample of relatively poor households is estimated at 3,954 per year.
Phonon Band Structure and Thermal Transport Correlation in a Layered Diatomic Crystal
To elucidate the relationship between a crystal's structure, its thermal
conductivity, and its phonon dispersion characteristics, an analysis is
conducted on layered diatomic Lennard-Jones crystals with various mass ratios.
Lattice dynamics theory and molecular dynamics simulations are used to predict
the phonon dispersion curves and the thermal conductivity. The layered
structure generates directionally dependent thermal conductivities lower than
those predicted by density trends alone. The dispersion characteristics are
quantified using a set of novel band diagram metrics, which are used to assess
the contributions of acoustic phonons and optical phonons to the thermal
conductivity. The thermal conductivity increases as the extent of the acoustic
modes increases, and decreases as the extent of the stop bands increases. The
sensitivity of the thermal conductivity to the band diagram metrics is highest
at low temperatures, where there is less anharmonic scattering, indicating that
dispersion plays a more prominent role in thermal transport in that regime. We
propose that the dispersion metrics (i) provide an indirect measure of the
relative contributions of dispersion and anharmonic scattering to the thermal
transport, and (ii) uncouple the standard thermal conductivity
structure-property relation to that of structure-dispersion and
dispersion-property relations, providing opportunities for better understanding
of the underlying physical mechanisms and a potential tool for material design.Comment: 30 pages, 10 figure
Non-perturbative effects and the resummed Higgs transverse momentum distribution at the LHC
We investigate the form of the non-perturbative parameterization in both the
impact parameter (b) space and transverse momentum (p_T) space resummation
formalisms for the transverse momentum distribution of single massive bosons
produced at hadron colliders. We propose to analyse data on Upsilon
hadroproduction as a means of studying the non-perturbative contribution in
processes with two gluons in the initial state. We also discuss the theoretical
errors on the resummed Higgs transverse momentum distribution at the LHC
arising from the non-perturbative contribution.Comment: 22 pages, 10 figure
Systematics and biology of some species of Micrurapteryx Spuler (Lepidoptera, Gracillariidae) from the Holarctic Region, with re-description of M. caraganella (Hering) from Siberia
During a DNA barcoding campaign of leaf-mining insects from Siberia, a genetically divergent lineage of a gracillariid belonging to the genus Micrurapteryx was discovered, whose larvae developed on Caragana Fabr. and Medicago L. (Fabaceae). Specimens from Siberia showed similar external morphology to the Palearctic Micrurapteryx gradatella and the Nearctic Parectopa occulta but differed in male genitalia, DNA barcodes, and nuclear genes histone H3 and 28S. Members of this lineage are re-described here as Micrurapteryx caraganella (Hering, 1957), comb. n., an available name published with only a brief description of its larva and leaf mine.
Micrurapteryx caraganella is widely distributed throughout Siberia, from Tyumen oblast in the West to Transbaikalia in the East. Occasionally it may severely affect its main host, Caragana arborescens Lam. This species has been confused in the past with Micrurapreryx gradatella in Siberia, but field observations confirm that M. gradatella exists in Siberia and is sympatric with M. caraganella, at least in the Krasnoyarsk region, where it feeds on different host plants (Vicia amoena Fisch. and Vicia sp.).
In addition, based on both morphological and molecular evidence as well as examination of type specimens, the North American Parectopa occulta Braun, 1922 and Parectopa albicostella Braun, 1925 are transferred to Micrurapteryx as M. occulta (Braun, 1922), comb. n. with albicostella as its junior synonym (syn. n.). Characters used to distinguish Micrurapteryx from Parectopa are presented and illustrated. These findings provide another example of the potential of DNA barcoding to reveal overlooked species and illuminate nomenclatural problems
A Methodology to Assist Faculty in Developing Successful Approaches for Achieving Learner Centered Information Systems Curriculum Outcomes: Team Based Methods
All industries face the interrelated challenges of indentifying and training the critical skills needed to be successful in the workplace. Specifically of interest to the information systems field is that any newly trained IS professional has to be equipped to solve increasingly difficult problems with great confidence and competence. In this paper we present the case for IS curriculum implementations (Landry 2008) based on the transformational learner centered methodologies (Saulnier 2008). With this approach, student learners take responsibility for their education and are accountable for the outcomes based on a continuous feedback and self adjustment of goal. We present a methodology for learner centered outcome development by using a template approach developed within a quality process improvement environment. This approach utilizes an existing model curriculum in developing the learner centered attributes. Examples for implementing the approach utilizing team based behaviors are provided
The Potential Added Value of Novel Hearing Therapeutics: An Early Health Economic Model for Hearing Loss
OBJECTIVE: To construct an early health economic model to assess the potential added value of novel hearing therapeutics, compared with the current standard of care. We use idiopathic sudden sensorineural hearing loss (ISSNHL) as a case example, because it is a lead indication for several emerging hearing therapeutics. METHODS: A decision analytic model was developed to assess the costs and effects of using novel hearing therapeutics for patients with ISSNHL. This was compared to the current standard of care. Input data were derived from literature searches and expert opinion. The study adopted a healthcare perspective of the UK National Health Service. Four analyses were conducted: 1) headroom, 2) scenario, 3) threshold, 4) sensitivity. RESULTS: The decision analytic model showed that novel therapeutics for ISSNHL have potential value both in terms of improved patient outcomes, as well as incremental net monetary benefit (iNMB). The base case analysis revealed an iNMB of £39,032 for novel therapeutics compared with the current standard of care. Results of the threshold and scenario analysis revealed that age of treatment and severity of ISSNHL are major determinants of iNMB for novel therapeutics. CONCLUSION: This article describes the first health economic model for novel therapeutics for hearing loss; and shows that novel hearing therapeutics can be cost-effective under NICE's cost-effectiveness threshold, with considerable room for improvement in the current standard of care. Our model can be used to inform the development of cost-effective hearing therapeutics; and help decision makers decide which therapeutics represent value for money
Phonon Transport Across a Vacuum Gap
Phonon transport across a silicon/vacuum-gap/silicon structure is modeled using lattice dynamics calculations and Landauer theory. The phonons transmit thermal energy across the vacuum gap via atomic interactions between the leads. Because the incident phonons do not encounter a classically impenetrable potential barrier, this mechanism is not a tunneling phenomenon. While some incident phonons transmit across the vacuum gap and remain in their original mode, many are annihilated and excite different modes. We show that the heat flux due to phonon transport can be 4 orders of magnitude larger than that due to photon transport predicted from near-field radiation theory
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