The logic of organizational markets: thinking through resource partitioning theory

Resource partitioning theory claims that Increasing concentration enhances the life chances of specialist organizations. We systemati- cally think through this theory,specify implicit background assump- tions,sharpen concepts,and rigorously check the theory s logic.As a result,we increase the theory s explanatory power,and claim contrary to received opinion that under certain eneral conditions, resource partitioning and the proliferation of specialists can take place independently of organizational mass and relative size effects, size localized competition,diversifying consumer tastes, increasing number of dimensions of the resource space,and changing niche widths. Our analysis makes furthermore clear that specialist and generalist strategies are asymmetric, and shows that not concentration enhances the life chances of specialists but economies of scale instead.Under the conditions explicated,we argue that if scale economies come to dominate,the number of organizations in the population increases, regardless of the incumbents sizes.

Aggregation without the Aggravation? Nonparametric Analysis of the Representative Consumer

Abstract: In the tradition of Afriat (1967), Diewert (1973) and Varian (1982), we provide a revealed preference characterisation of the representative consumer. Our results are simple and complement those of Gorman (1953, 1961), Samuelson (1956) and others. They can also be applied to data very readily and without the need for auxilliary parametric or statistical assumptions. We investigate the application of our characterisation by means of a balanced microdata panel survey. Our findings provide robust evidence against the existence of a representative consumer for our data.revealed preference;aggregation;Gorman Polar Form;GARP

Relative compactness conditions for topos

In this paper a systematic study is made of various notions of proper map in the context of toposes Modulo some separation conditions a proper map Y X of spaces is generally understood to be a continuous function which preserves compactness of subspaces under inverse image and which therefore in particular has compact bers In this spirit a rst denition of proper map between toposes was put forward by Johnstone in There a map of toposes fF E was called proper if fF is a compact lattice object in the topos E This is probably the most direct way of expressing that F is compact when viewed as a topos over the base E In fact Johnstone used the term perfect rather than proper and developed the theory mostly in the context of localic maps between toposes se

Firm Investment and Monetary Policy Transmission in the Euro Area.

We present a comparable set of results on the monetary transmission channels on firm investment for the four largest euro-area countries (Germany, France, Italy and Spain). With particularly rich micro datasets for each country containing over 215,000 observations from 1985 to 1999, we ex-plore what can be learned about the interest channel and the broad credit channel. For each of those countries, we estimate neo-classical investment relationships, explaining investment by its user cost, sales and cash flow. We find investment to be sensitive to user cost changes in all those four countries. This implies an operative interest channel in these euro-area countries. We also find in-vestment in all countries to be quite sensitive to cash flow movements. However, only in Italy do smaller firms react more to cash flow movements than large firms, implying that a broad credit channel might not be equally pervasive in all countries.Investment, Monetary transmission channels, User cost of capital.

The inner radio jet region and the complex environment of SS433

We present multi-frequency VLBA+VLA observations of SS433 at 1.6, 5 and 15 GHz. These observations provide the highest angular resolution radio spectral index maps ever made for this object. Motion of the components of SS433 during the observation is detected. In addition to the usual VLBI jet structure, we detect two radio components in the system at an anomalous position angle. These newly discovered radio emitting regions might be related to a wind-like equatorial outflow or to an extension of the accretion disk. We show that the radio core component is bifurcated with a clear gap between the eastern and western wings of emission. Modelfitting of the precessing jets and the moving knots of SS433 shows that the kinematic centre -- i.e. the binary -- is in the gap between the western and eastern radio core components. Spectral properties and observed core position shifts suggest that we see a combined effect of synchrotron self-absorption and external free-free absorption in the innermost AU-scale region of the source. The spatial distribution of the ionized matter is probably not spherically symmetric around the binary, but could be disk-like.Comment: Accepted for publication by Astronomy and Astrophysic

Price setting in the euro area: Some stylised facts from Individual Producer Price Data

This paper documents producer price setting in 6 countries of the euro area: Germany, France, Italy, Spain, Belgium and Portugal. It collects evidence from available studies on each of those countries and also provides new evidence. These studies use monthly producer price data. The following five stylised facts emerge consistently across countries. First, producer prices change infrequently: each month around 21% of prices change. Second, there is substantial cross-sector heterogeneity in the frequency of price changes: prices change very often in the energy sector, less often in food and intermediate goods and least often in non-durable non- food and durable goods. Third, countries have a similar ranking of industries in terms of frequency of price changes. Fourth, there is no evidence of downward nominal rigidity: price changes are for about 45% decreases and 55% increases. Fifth, price changes are sizeable compared to the inflation rate. The paper also examines the factors driving producer price changes. It finds that costs structure, competition, seasonality, inflation and attractive pricing all play a role in driving producer price changes. In addition producer prices tend to be more flexible than consumer prices.

Molecular footprint of drug-selective pressure in a human immunodeficiency virus transmission chain

Known human immunodeficiency virus (HIV) transmission histories are invaluable models for investigating the evolutionary and transmission dynamics of the virus and to assess the accuracy of phylogenetic reconstructions. Here we have characterized an HIV-1 transmission chain consisting of nine infected patients, almost all of whom were treated with antiviral drugs at later stages of infection. Partial pol and env gp41 regions of the HIV genome were directly sequenced from plasma viral RNA for at least one sample from each patient. Phylogenetic analyses in pol using likelihood methods inferred an evolutionary history not fully compatible with the known transmission history. This could be attributed to parallel evolution of drug resistance mutations resulting in the incorrect clustering of multidrug-resistant virus. On the other hand, a fully compatible phylogenetic tree was reconstructed from the env sequences. We were able to identify and quantify the molecular footprint of drug-selective pressure in pol using maximum likelihood inference under different codon substitution models. An increased fixation rate of mutations in the HIV population of the multidrug-resistant patient was demonstrated using molecular clock modeling. We show that molecular evolutionary analyses, guided by a known transmission history, can reveal the presence of confounding factors like natural selection and caution should be taken when accurate descriptions of HIV evolution are required.status: publishe