Fees and the efficiency of tradable permit systems: an experimental approach

The paper presents the results of an economic experiment in which the effects of fees on allocative efficiency of tradable utilization permits (e.g. pollution permits) are explored. Laboratory subjects (university students) play the roles of firms whose generic product requires a specific input or permits. Scarcity is exogenously introduced by a fixed supply of tradable production permits. Three treatments are compared: A) no fee imposed; B) a fixed tax per permit; C) partial retraction of permits which are reissued by auction. We regard B and C as two ways of imposing fees. Our results indicate that, after controlling for deviation of permit prices from a prediction based on fundamentals, fees have an impact on distribution of permits. Interestingly, a fixed tax enhances efficiency compared to the case of no fees, while retraction and reallocation by auction reduces efficiency compared to both alternative treatments. Apparently, subjects’ decision making is affected by the imposition of fees, but it matters how such costs are presented or framed.Tradable permits, taxation, auctions, efficiency, experimental economics

Quantum effects in the diffusion of hydrogen on Ru(0001)

An understanding of hydrogen diffusion on metal surfaces is important, not just for its role in heterogeneous catalysis and hydrogen fuel cell technology, but also because it provides model systems where tunneling can be studied under well-defined conditions. Here we report helium spin-echo measurements of the atomic-scale motion of hydrogen on the Ru(0001) surface between 75 and 250 K. Quantum effects are evident at temperatures as high as 200 K, while below 120 K we observe a tunneling-dominated temperature independent jump rate of 1.9$\times$10$^9$ s$^{-1}$, many orders of magnitude faster than previously seen. Quantum transition state theory calculations based on ab initio path-integral simulations reproduce the temperature dependence of the rate at higher temperatures and predict a crossover to tunneling-dominated diffusion at low temperatures, although the tunneling rate is under-estimated, highlighting the need for future experimental and theoretical studies of hydrogen diffusion on well-defined surfaces.Comment: 15 pages, 3 figure

The Boson peak in supercooled water

We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line TW. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih.We thank S. V. Buldyrev and S. Sastry for helpful discussions. The simulations were in part performed using resources provided by the Swedish National Infrastructure for Computing (SNIC) at the NSC and HPC2N centers. LGMP, KTW and DS were supported by the Swedish Research Council. KTW is also supported by the Icelandic Research Fund through the START programme. PK acknowledges the support of National Academies Keck Future Initiatives award. HES thanks NSF Grants No. CHE0911389, No. CHE0908218, and No. CHE-1213217. (Swedish Research Council; Icelandic Research Fund through the START programme; National Academies Keck Future Initiatives award; CHE0911389 - NSF; CHE0908218 - NSF; CHE-1213217 - NSF)Published versio

The Boson peak in supercooled water

We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores, and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line $T_W$. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih.Comment: 25 pages, 9 figure

Timing of Latest Eocene Molluscan Extinction Patterns in Mississippi

Molluscs removed from 12 bulk samples of the Yazoo Formation (upper Eocene), exposed in a quarry at Cynthia, Mississippi, are similar in com- position and diversity to those found in the underlying upper Eocene Moodys Branch Formation, when dif- ferences in outcrop area are considered (74% of the Yazoo species are also found in the Moodys Branch). This suggests there was no significant extinction during the late Eocene (at the P15/P16 biozone boundary) as has been reported for planktic foraminifera. Only 11.4% of the species from the Yazoo extend into the Oligocene Red Bluff Formation, suggesting a large molluscan extinction at or near the Eocene-Oligocene boundary. The presence in the lowermost Red Bluff of an assemblage with a relatively high diversity dominated by suspension-feeding bivalves suggests that the molluscan fauna had recovered from the extinction by the earliest Oli- gocene

Androgen Mediation of Elaborate Male Traits: The Effects of Dihydrotestosterone Administration on Vocal Quality in Male Green Treefrogs, Hyla Cinerea

THOR MATTHEW GOODFELLOW: Androgen Mediation of Elaborate Male Traits: The Effects of Dihydrotestosterone Administration on Vocal Quality in Male Green Treefrogs, Hyla cinerea (Under the direction of Dr. Christopher Leary) Elevated androgen levels are well known to mediate the expression of male courtship behaviors and elaborate traits, but whether androgens act via threshold or graded effects is less clear. Models linking elaborate male traits to the endocrine system often assume that androgens have a graded effect on the magnitude or extent of elaborate male traits and that female preference for more elaborate male traits thus drives concordant directional selection on circulating androgen levels. To test this hypothesis, I examined the effects of dihydrotestosterone (DHT) administration on the quality of advertisement calls produced by male Hyla cinerea. Advertisement calls are an elaborate male trait known to be androgen dependent, and females prefer longer calls produced at a faster rate (i.e., high vocal effort) and calls with carrier frequencies that reflect the mean of the population. Analysis of vocalizations prior to treatment indicated that DHT level was not related to call duration, intercall duration, vocal effort, or call carrier frequency. Analysis of plasma hormone levels from blood samples taken before and after treatment showed that DHT injections elevated androgen levels relative to castor oil-injected controls. However, there was no evidence that androgen administration altered call duration, intercall duration, vocal effort, or carrier frequency of the calls of this species. My results thus provide little support for a graded effect of androgens on vocalization in this species. A graded effect of androgens on male sexual signals is central to current models explaining the evolution of elaborate male traits and the endocrine system, but modifications to these models may be necessary