Spatial Monopoly Pricing in a Stochastic Environment

This paper reexamines the welfare implications of three pricing regimes (mill, uniform and discriminatory) for a monopoly in a stochastic environment. It con-siders a risk-averse monopolist faces two markets with stochastic and linear demands. The monopolist is assumed to commit to an irreversible price in each market before the uncertainty is resolved. Several unconventional results are shown to be triggered by the presence of demand uncertainty. The reason for the reversal of orthodox intuition is the asymmetry in the risk chacteristics of the markets and the willingness of the monopolist to trade increased level of expected prots for reduced risk.spatial pricing, monopoly, demand uncertainty

Functional analysis of Methanocaldococcus jannaschii RNA polymerase A’ ‘bridge-helix’ using a fully automated high-throughput robotic system

RNA polymerases (RNAPs) are the ‘engines’ of cellular transcriptional machineries, which are essential to life and highly conserved from bacteria to eukaryotes. Though crystal structures of both eukaryotic and bacterial RNAPs have been intensively studied, the relationships between structures and appropriate functions of such enzymes in eukaryotes remain unknown since there has not yet been possible to constitute any active eukaryotic RNAPs from recombinant subunits. The successfully assembled archaeal counterparts have provided an alternative approach to study the eukaryotic system due to not only the structural similarities between these enzymes but also the structural and functional similarities of their basal transcriptional machineries. ‘Bridge-helix’ is one of the most highly conserved structures near the catalytic site of RNAPs, which has been proposed to play an important role in coordinating the processing of nucleic acid substrates through the active center. 17 adjacent residues (mjA’-L814 to mjA’-R830) within the central portion of Methanocaldococcus jannaschii A’ ‘bridge-helix’ were chosen for a systematic high-throughput sitedirected mutagenesis approach using a novel robotic system. This robotic system is fully automated without any human interventions that may enormously reduce human errors and effectively increase the number of samples that could be processed in parallel. The results obtained from such high-throughput approach showed a wide spectrum of in vitro phenotypes ranging from complete loss of function to ‘superactivity’. According to the unexpected functional evidences obtained with the ‘superactive’ mutants, we propose a highly favorable kinked ‘bridge-helix’ conformation for the nucleotide addition cycle that has to be precisely localized in certain positions in order to increase the specific activity of RNAPs. The fact that no additive effects have been found so far in any of the ‘superactive’ double mutants suggests that various single amino-acid substitution ‘superactive’ mutants may affect the same process in a functionally overlapping and mutually independent manner

Three new and remarkable species of mosses from China and the Philippines

Distichophyllum meizhii Tan & Lin and D. wanianum Tan & Lin (Hookeriaceae) collected from southwestern region of China are described as new to science. Also, Horikawaea redfearnii Tan & Lin is described as a new species based on collections from Hainan Island of China and Palawan Island of the Philippines. The sporophytic specimen of Horikawaea Nog. was collected for the first time and support a family placement in Pterobryaceae

Spatial Economic Theory of Pollution Control under Stochastic Emissions

This paper examines the eectiveness of environmental policies in curtailing pollution of a rm which is operating in a space economy under stochastic emissions. We consider a general n-input planar space production-location model, in which the output is produced jointly with the byproduct pollution. Although production is nonstochastic, the resulting pollution emission is assumed to have a random component, and the polluting rm must make its production and location decisions before the uncertainty is resolved. We provide some propositions concerning the comparative statics of the polluting rm's location choices, urban pollution concentration, and the relative impact of regulation via emission taxes to that of emission standards.location theory, pollution control, emission uncertainty

A transient solution for vesicle electrodeformation and relaxation

A transient analysis for vesicle deformation under DC electric fields is developed. The theory extends from a droplet model, with the additional consideration of a lipid membrane separating two fluids of arbitrary properties. For the latter, both a membrane-charging and a membrane-mechanical model are supplied. The vesicle is assumed to remain spheroidal in shape for all times. The main result is an ODE governing the evolution of the vesicle aspect ratio. The effects of initial membrane tension and pulse length are examined. The model prediction is extensively compared with experimental data, and is shown to accurately capture the system behavior in the regime of no or weak electroporation. More importantly, the comparison reveals that vesicle relaxation obeys a universal behavior regardless of the means of deformation. The process is governed by a single timescale that is a function of the vesicle initial radius, the fluid viscosity, and the initial membrane tension. This universal scaling law can be used to calculate membrane properties from experimental data

Thin-Shell Deployable Reflectors with Collapsible Stiffeners: Experiments and Simulations

This paper presents an experimental and computational study of four deployable reflectors with collapsible edge stiffeners, to verify the differences in behavior that had been predicted in a previous theoretical study. The experimental models have different geometric configurations and are made of two different plastics. Both folding experiments and vibration tests in the fully deployed configuration are carried out on each model, and it is shown that good correlation with finite element simulations can be achieved if detailed effects such as material nonlinearity, geometric imperfections, air, and gravity effects are included in the computer models

Robust Influence Maximization

In this paper, we address the important issue of uncertainty in the edge influence probability estimates for the well studied influence maximization problem --- the task of finding $k$ seed nodes in a social network to maximize the influence spread. We propose the problem of robust influence maximization, which maximizes the worst-case ratio between the influence spread of the chosen seed set and the optimal seed set, given the uncertainty of the parameter input. We design an algorithm that solves this problem with a solution-dependent bound. We further study uniform sampling and adaptive sampling methods to effectively reduce the uncertainty on parameters and improve the robustness of the influence maximization task. Our empirical results show that parameter uncertainty may greatly affect influence maximization performance and prior studies that learned influence probabilities could lead to poor performance in robust influence maximization due to relatively large uncertainty in parameter estimates, and information cascade based adaptive sampling method may be an effective way to improve the robustness of influence maximization.Comment: 12 pages, 4 figures, Technical Report, contains proofs for the paper appeared in KDD'201