Competition and Cooperation in Divisible Good Auctions: An Experimental Examination

An experimental approach is used to examine the performance of three different multi-unit auction designs: discriminatory, uniform-price with fixed supply, and uniform-price with endogenous supply. We find that the strategies of the individual bidders and the aggregate demand curves are inconsistent with theoretically identified equilibrium strategies. The discriminatory auction is found to be more susceptible to collusion than are the uniform-price auctions, and so contrary to theoretical predictions and previous experimental results the discriminatory auction provides the lowest average revenue. Consistent with theoretical predictions, bidder demands are more elastic with reducible supply or discriminatory pricing than in the uniform-price auction with fixed supply. Despite a lack of a priori differences across bidders, the discriminatory auction results in significantly more symmetric allocations.

Competition and Cooperation in Divisible Good Auctions: An Experimental Examination

An experimental approach is used to examine the performance of three different multi-unit auction designs: discriminatory, uniform-price with fixed supply, and uniform-price with endogenous supply. We find that the strategies of the individual bidders and the aggregate demand curves are inconsistent with theoretically identified equilibrium strategies. The discriminatory auction is found to be more susceptible to collusion than are the uniform-price auctions, and so contrary to theoretical predictions and previous experimental results, the discriminatory auction provides the lowest average revenue. Consistent with theoretical predictions, bidder demands are more elastic with reducible supply or discriminatory pricing than in the uniform-price auction with fixed supply. Despite a lack of a priori differences across bidders, the discriminatory auction results in significantly more symmetric allocations.Divisible good, Auctions, Experimental economics

Measurement of the specific surface area of snow using infrared reflectance in an integrating sphere at 1310 and 1550 nm

International audienceEven though the specific surface area (SSA) and the snow area index (SAI) of snow are crucial variables to determine the chemical and climatic impact of the snow cover, few data are available on the subject. We propose here a novel method to measure snow SSA and SAI. It is based on the measurement of the hemispherical infrared reflectance of snow samples using the DUFISSS instrument (DUal Frequency Integrating Sphere for Snow SSA measurement). DUFISSS uses the 1310 or 1550 nm radiation of laser diodes, an integrating sphere 15 cm in diameter, and InGaAs photodiodes. For SSA60 m2 kg−1, snow is usually of low density (typically 30 to 100 kg m−3), resulting in insufficient optical depth and 1310 nm radiation reaches the bottom of the sample, causing artifacts. The 1550 nm radiation is therefore used for SSA>60 m2 kg−1. Reflectance is then in the range 5 to 12% and the accuracy on SSA is 12%. We propose empirical equations to determine SSA from reflectance at both wavelengths, with that for 1310 nm taking into account the snow density. DUFISSS has been used to measure the SSA of snow and the SAI of snowpacks in polar and Alpine regions

Heterogeneous impact of dust on tropospheric ozone: Sensitivity to season, species, and uptake rates

Abstract. Heterogeneous chemistry on mineral dust particles causes significant reductions in important tropospheric trace gases such as O 3 , OH, and HNO 3 in dust-dominated regions such as the North African Tropical Atlantic region. We analyze the spatial and temporal modes of dust-induced heterogeneous ozone removal (∆ H O 3 ) using empirical orthogonal functions (EOFs) and principal components analysis. We use the results to attribute ozone removal to specific pathways, and to assess the sensitivity of ozone removal to uncertainties in key heterogeneous uptake rates. The first EOF mode dominates ∆ H O 3 variance (93%) and shows that dust reduces O 3 through heterogeneous reactions globally and year-around with the maximum in July. The second mode explains only 4% of ∆ H O 3 spatial variance yet accounts for most ∆ H O 3 seasonality. With best-guess uptake coefficients, indirect ozone reduction due to HNO 3 uptake exceeds direct heterogeneous uptake of O 3 . However, uncertainties in uptake rates allow the possibility that direct O 3 uptake exceeds HNO 3 -induced O 3 uptake, especially in Northern Spring. Recently published HNO 3 uptake coefficients on authentic dust range from 10 −5 < γ HNO 3 < 0.2, and imply that dust destroys 0.5-5.2% of tropospheric O 3 , respectively. Improved γ HNO 3 measurements and correct model representation of global dust composition, deliquesence, and aging are required to further reduce these order-of-magnitude uncertainties

Toxic Epidermal Necrolysis After Topical Intranasal Application of Mupirocin

We describe a case of toxic epidermal necrolysis after intranasal application of mupirocin in a 76-year-old woman. The drug was given for eradication of methicillin-resistant Staphylococcus aureu

NASA Dataset Interoperability Recommendations for Earth Science

NASA ESDS (Earth Science Data and Information System) Dataset Interoperability Working Group has been developing recommendations since 2012 aimed at improving interoperability of EOS (Earth Observing System) datasets. The first set of recommendations were published in 2016 as ESDS RFC-028. The latest set of recommendations is currently undergoing review and will be available as ESDS RFC-036 soon.This talk will inform the ESIP (Earth Science Information Partners) community about the recommendations because their application is relevant to other data producers as well

Global estimates of mineral dust aerosol iron and aluminum solubility that account for particle size using diffusion-controlled and surface-area-controlled approximations

Mineral aerosol deposition is recognized as the dominant source of iron to the open ocean and the solubility of iron in the dust aerosol is highly variable, with measurements ranging from 0.01–80%. Global models have difficulty capturing the observed variations in solubility, and have ignored the solubility dependence on aerosol size. We introduce two idealized physical models to estimate the size dependence of mineral aerosol solubility: a diffusion‐controlled model and a surface‐area‐controlled model. These models produce differing time‐ and space‐varying solubility maps for aerosol Fe and Al given the dust age at deposition, size‐resolved dust entrainment fields, and the aerosol acidity. The resulting soluble iron deposition fluxes are substantially different, and more realistic, than a globally uniform solubility approximation. The surface‐area‐controlled solubility varies more than the diffusion‐controlled solubility and better captures the spatial pattern of observed solubility in the Atlantic. However, neither of these two models explains the large solubility variation observed in the Pacific. We then examine the impacts of spatially variable, size‐dependent solubility on marine biogeochemistry with the Biogeochemical Elemental Cycling (BEC) ocean model by comparing the modeled surface ocean dissolved Fe and Al with observations. The diffusion‐based variable solubility does not significantly improve the simulation of dissolved Fe relative to a 5% globally uniform solubility, while the surface‐area‐based variable solubility improves the simulation in the North Atlantic but worsens it in the Pacific and Indian Oceans

Present‐day climate forcing and response from black carbon in snow,

[1] We apply our Snow, Ice, and Aerosol Radiative (SNICAR) model, coupled to a general circulation model with prognostic carbon aerosol transport, to improve understanding of climate forcing and response from black carbon (BC) in snow. Building on two previous studies, we account for interannually varying biomass burning BC emissions, snow aging, and aerosol scavenging by snow meltwater. We assess uncertainty in forcing estimates from these factors, as well as BC optical properties and snow cover fraction. BC emissions are the largest source of uncertainty, followed by snow aging. The rate of snow aging determines snowpack effective radius (r e ), which directly controls snow reflectance and the magnitude of albedo change caused by BC. For a reasonable r e range, reflectance reduction from BC varies threefold. Inefficient meltwater scavenging keeps hydrophobic impurities near the surface during melt and enhances forcing. Applying biomass burning BC emission inventories for a strong (1998) and weak Citation: Flanner, M. G., C. S. Zender, J. T. Randerson, and P. J. Rasch (2007), Present-day climate forcing and response from black carbon in snow