Spacial Equilibrium in a State Space Approach to Demand Uncertainty

Firms are likely to be uncertain about consumer preferences when launching products. The existing literature models preference uncertainty as an additive shock to the consumer distribution in a characteristic space model. The additive shock only shifts the mean of the consumers' ideal points. We generalize this approach to a state space model in which a vector of parameters can give rise to dierent distributions of consumer tastes in dierent states, allowing other moments of the consumer density to be uncertain. An equilibrium existence result is given. In the case of symmetric distributions, the unique subgame-perfect equilibrium can be described by a simple closed-form solution.Location; Product Dierentiation; Uncertainty; Hotelling

Smallness of a commodity and partial equilibrium analysis

Partial equilibrium analysis has a conceptual dilemma that its object should be negligibly small in order to be free from income effect but then the consumer does not care for it and the notion of willingness to pay for it does not make sense. In the setting of a continuum of commodities, we propose a limiting procedure which transforms the general many-commodity framework into a partial single-commodity framework. In the limit, willingness to pay for a commodity is established as a density notion and it is shown to be free from income effect. This pins down an exact relationship between general equilibrium analysis and partial equilibrium analysis

Non-Linear Interactions between Consumers and Flow Determine the Probability of Plant Community Dominance on Maine Rocky Shores

Although consumers can strongly influence community recovery from disturbance, few studies have explored the effects of consumer identity and density and how they may vary across abiotic gradients. On rocky shores in Maine, recent experiments suggest that recovery of plant- or animal- dominated community states is governed by rates of water movement and consumer pressure. To further elucidate the mechanisms of consumer control, we examined the species-specific and density-dependent effects of rocky shore consumers (crabs and snails) on community recovery under both high (mussel dominated) and low flow (plant dominated) conditions. By partitioning the direct impacts of predators (crabs) and grazers (snails) on community recovery across a flow gradient, we found that grazers, but not predators, are likely the primary agent of consumer control and that their impact is highly non-linear. Manipulating snail densities revealed that herbivorous and bull-dozing snails (Littorina littorea) alone can control recovery of high and low flow communities. After ∼1.5 years of recovery, snail density explained a significant amount of the variation in macroalgal coverage at low flow sites and also mussel recovery at high flow sites. These density-dependent grazer effects were were both non-linear and flow-dependent, with low abundance thresholds needed to suppress plant community recovery, and much higher levels needed to control mussel bed development. Our study suggests that consumer density and identity are key in regulating both plant and animal community recovery and that physical conditions can determine the functional forms of these consumer effects

Density-and trait-mediated effects of a parasite and a predator in a tri-trophic food web

1. Despite growing interest in ecological consequences of parasitism in food webs, relatively little is known about effects of parasites on long-term population dynamics of non-host species or about whether such effects are density- or trait- mediated. 2. We studied a tri-trophic food chain comprised of: (i) a bacterial basal resource (Serratia fonticola), (ii) an intermediate consumer (Paramecium caudatum), (iii) a top predator (Didinium nasutum), and (iv) a parasite of the intermediate consumer (Holospora undulata). A fully-factorial experimental manipulation of predator and parasite presence/absence was combined with analyses of population dynamics, modelling, and analyses of host (Paramecium) morphology and behavior. 3. Predation and parasitism each reduced the abundance of the intermediate consumer (Paramecium), and parasitism indirectly reduced the abundance of the basal resource (Serratia). However, in combination, predation and parasitism had non-additive effects on the abundance of the intermediate consumer, as well as on that of the basal resource. In both cases, the negative effect of parasitism seemed to be effaced by predation. 4. Infection of the intermediate consumer reduced predator abundance. Modelling and additional experimentation revealed that this was most likely due to parasite reduction of intermediate host abundance (a density-mediated effect), as opposed to changes in predator functional or numerical response. 5. Parasitism altered morphological and behavioural traits, by reducing host cell length and increasing the swimming speed of cells with moderate parasite loads. Additional tests showed no significant difference in Didinium feeding rate on infected and uninfected hosts, suggesting that the combination of these modifications does not affect host vulnerability to predation. However, estimated rates of encounter with Serratia based on these modifications were higher for infected Paramecium than for uninfected Paramecium. 6. A mixture of density-mediated and trait-mediated indirect effects of parasitism on non- host species creates rich and complex possibilities for effects of parasites in food webs that should be included in assessments of possible impacts of parasite eradication or introduction

What can changes in structural factors tell us about unemployment in Europe?

This paper examines the impact of temporal variation in labour market institutions and other structural factors on unemployment in Europe. These include the influence of trade unions, social security benefits, employment security, mismatch between job seekers and vacancies, the minimum wage and factors which drive a wedge between consumer and producer prices. With this aim, a system including a labour demand and a wage equation is estimated in pooled time-series data for the six largest EU countries for the 1980s and 1990s, allowing for country-specific fixed-effects, institutional effects and adjustment terms. Our estimates suggest that changes in regional mismatch, trade union density and the ratio between consumer and producer prices are positively associated with structural unemployment. This result is robust to a wide variety of different specifications of the model, including a larger sample of eight EU countries. No consistent role is found for the other institutional factors. JEL Classification: E24, J30, C33Labour market institutions, panel estimation, structural unemployment

Maximum-Likelihood Sequence Detector for Dynamic Mode High Density Probe Storage

There is an increasing need for high density data storage devices driven by the increased demand of consumer electronics. In this work, we consider a data storage system that operates by encoding information as topographic profiles on a polymer medium. A cantilever probe with a sharp tip (few nm radius) is used to create and sense the presence of topographic profiles, resulting in a density of few Tb per in.2. The prevalent mode of using the cantilever probe is the static mode that is harsh on the probe and the media. In this article, the high quality factor dynamic mode operation, that is less harsh on the media and the probe, is analyzed. The read operation is modeled as a communication channel which incorporates system memory due to inter-symbol interference and the cantilever state. We demonstrate an appropriate level of abstraction of this complex nanoscale system that obviates the need for an involved physical model. Next, a solution to the maximum likelihood sequence detection problem based on the Viterbi algorithm is devised. Experimental and simulation results demonstrate that the performance of this detector is several orders of magnitude better than the performance of other existing schemes.Comment: This paper is published in IEEE Trans. on communicatio

Is There a Demand Response by Patients in Primary Care?

We test whether a demand response by patients exists in the Norwegian primary care sector. In Norway, physicians are remunerated either by salary or by incentive contract, and we have access to a large data survey that allows us to study the relationship between consumer satisfaction with primary physician services and the way physicians are paid. In addition, we can identify areas (municipalities) where market demand for primary physicians’ services is responsive to effort. When a demand response exists, we expect that patients’ benefit is higher and that patients are more satisfied when visiting a contract physician. As expected, we find very small effects of the salary physician density on reported patient satisfaction in municipalities where market demand is nonresponsive to physicians’ choice of effort. In municipalities with responsive market demand, we find a negative association between salary physician density and patients’ satisfaction with their physician.Physician behavior; Remuneration contracts; Patients’ satisfaction

Remarkable Hydrogen Storage on Beryllium Oxide Clusters: First Principles Calculations

Since the current transportation sector is the largest consumer of oil, and subsequently responsible for major air pollutants, it is inevitable to use alternative renewable sources of energies for vehicular applications. The hydrogen energy seems to be a promising candidate. To explore the possibility of achieving a solid-state high-capacity storage of hydrogen for onboard applications, we have performed first principles density functional theoretical calculations of hydrogen storage properties of beryllium oxide clusters (BeO)$_{n}$ (n=2 -- 8). We observed that polar BeO bond is responsible for H$_{2}$ adsorption. The problem of cohesion of beryllium atoms does not arise, as they are an integral part of BeO clusters. The (BeO)$_{n}$ (n=2 -- 8) adsorbs 8--12 H$_{2}$ molecules with an adsorption energy in the desirable range of reversible hydrogen storage. The gravimetric density of H$_{2}$ adsorbed on BeO clusters meets the ultimate 7.5 wt% limit, recommended for onboard practical applications. In conclusion, beryllium oxide clusters exhibit a remarkable solid-state hydrogen storage.Comment: This document is the Accepted Manuscript version of a Published Work that appeared in final form in JPCC, copyright American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see , see http://pubs.acs.org/doi/abs/10.1021/jp410994