Product Diversification and Labor Productivity Dispersion in German Manufacturing Industries

Empirical research has shown tremendous productivity differences, even within narrowly defined industries. A great host of studies is explainsing this productivity disparity by factors such as idiosyncratic technology shocks, input price differences, management skills, or international trade. Although these explanations are undoubtedly important, the current paper suggests that product diversification strategies of firms can also play an important role. Using a matched producer-product panel dataset of German manufacturing industries over the period 2003-2006, we find that the average degree of product diversification across industry establishments is positively related to within-industry labor productivity dispersion.Product Diversification, Productivity, Industrial Dynamics

Identification of the mitochondrial receptor complex in Saccharomyces cerevisiae

Mitochondrial protein import involves the recognition of preproteins by receptors and their subsequent translocation across the outer membrane. In Neurospora crassa, the two import receptors, MOM19 and MOM72, were found in a complex with the general insertion protein, GIP (formed by MOM7, MOM8, MOM30 and MOM38) and MOM22. We isolated a complex out of S. cerevisiae mitochondria consisting of MOM38/ISP42, the receptor MOM72, and five new yeast proteins, the putative equivalents of N. crassa MOM7, MOM8, MOM19, MOM22 and MOM30. A receptor complex isolated out of yeast cells transformed with N. crassa MOM19 contained the N. crassa master receptor in addition to the yeast proteins. This demonstrates that the yeast complex is functional, and provides strong evidence that we also have identified the yeast MOM19

Mitochondrial protein import

The precursors of the mitochondrial proteins ADP/ATP carrier (AAC) and F1-ATPase subunit β (F1β) were accumulated at the stages of binding to receptor sites on the mitochondrial outer membrane, or in contact sites between outer and inner membranes. Specific antibodies raised against the mature proteins were added to the isolated mitochondria and efficiently bound to these translocation intermediates. Further movement of the precursors to consecutive steps along their import pathway was thereby inhibited. Controls showed that precursor proteins which were inserted into or translocated across the outer membrane were not recognized by the antibodies unless the mitochondrial membranes were disrupted. We conclude that the trapped translocation intermediates have antigenic sites exposed to the outside of the outer membrane

Numerical modelling of the coupling efficiency of single quantum emitters in photonic-crystal waveguides

Planar photonic nanostructures have recently attracted a great deal of attention for quantum optics applications. In this article, we carry out full 3D numerical simulations to fully account for all radiation channels and thereby quantify the coupling efficiency of a quantum emitter embedded in a photonic-crystal waveguide. We utilize mixed boundary conditions by combining active Dirichlet boundary conditions for the guided mode and perfectly-matched layers for the radiation modes. In this way, the leakage from the quantum emitter to the surrounding environment can be determined and the spectral and spatial dependence of the coupling to the radiation modes can be quantified. The spatial maps of the coupling efficiency, the $\beta$-factor, reveal that even for moderately slow light, near-unity $\beta$ is achievable that is remarkably robust to the position of the emitter in the waveguide. Our results show that photonic-crystal waveguides constitute a suitable platform to achieve deterministic interfacing of a single photon and a single quantum emitter, which has a range of applications for photonic quantum technology

Product Quality, Product Price, and Share Dynamics in the German Compact Car Market

The present paper examines one of the central elements of evolutionary thinking - competition formalized by the replicator dynamics mechanism. Using data on product characteristics of automobiles sold on the German domestic market over the period 2001-2006, we construct a competitiveness or fitness variable for each car model applying non-parametric efficiency measurement techniques. The basic question we intend to answer is whether cars providing a higher quality-price ratio for consumers tend to increase their market share compared to variants with lower quality-price ratios. The relationship between a car models' fitness and its market performance is empirically tested in a regression framework. The results show that the principle of `growth of the fitter' is working as suggested by evolutionary theory. In particular, we find that car models with considerably lower fitness than the market average lose, whereas models with above-average fitness gain additional market shares.Replicator Dynamics, Product Characteristics, Data Envelopment Analysis

Same Same But Different? A Two-Foci Perspective on Trust in Information Systems

Trust is one of the most important factors driving the adoption and use of information systems. The goal of this paper is to provide a first evaluation of a conceptual piece claiming a) that users distinguish between their trust in an IS and the provider of this IS and b) that both kinds of trust are important for the success sustainable success of IS providers. To evaluate the claims, a research model is developed and evaluated using data of 234 students during the introduction of a new IS at an European university. The results provide support for both claims, since the correlation between the two trust constructs is low, and the nomological networks differ. Regarding the importance of both constructs, trust in the IS is found to have an important impact of the use of the IS, whereas trust in the provider is a major driver of the users’ loyalty

MOM19, an import receptor for mitochondrial precursor proteins

We have identified a 19 kd protein of the mitochondrial outer membrane (MOM19). Monospecific IgG and Fab fragments directed against MOM19 inhibit import of precursor proteins destined for the various mitochondrial subcompartments, including porin, cytochrome c1, Fe/S protein, F0 ATPase subunit 9, and F1 ATPase subunit β. Inhibition occurs at the level of high affinity binding of precursors to mitochondria. Consistent with previous functional studies that suggested the existence of distinct import sites for ADP/ATP carrier and cytochrome c, we find that import of those precursors is not inhibited. We conclude that MOM19 is identical to, or closely associated with, a specific mitochondrial import receptor

A dynamic model of the mitochondrial protein import machinery

Many proteins are translocated into or across two mem-branes in order to reach their functional destination; these include many nuclear-encoded mitochondrial and chloro-plast proteins, as well as proteins transported into or across the outer membrane of gram-negative bacteria. In eukaryotes, mechanistic insights have been obtained mainly with the mitochondrial two-membrane transport system. By generating translocation intermediates that span both mitochondrial membranes at the same time, it has been demonstrated that the outer and inner mem-brane translocation machineries cooperate in the import of preproteins (Hart1 and Neupert, 1990; Baker and Schatz, 1991). Translocation contact sites were defined as mito-chondrial import sites where the outer and inner mem-branes are so close together that they can be spanned b

The mitochondrial receptor complex

The receptor complex in the mitochondrial outer membrane, which consists of at least seven different proteins, is responsible for the recognition and translocation of cytosolically synthesized preproteins. Two of its subunits, MOM19 and MOM72, function as surface receptors for preproteins. Four other subunits (MOM38, MOM30, MOM8, and MOM7) have been suggested to constitute the general insertion pore (GIP). Here we report on the structure and function of MOM22. MOM22 is anchored in the outer membrane by a single transmembrane segment. The highly negatively charged N-terminal domain is exposed to the cytosol and the C-terminal domain to the intermembrane space. MOM22 appears to be a central component of the receptor complex, required for the transfer of preproteins from the receptors to the GIP. We speculate that the negatively charged domain of MOM22 is involved in the transfer of positively charged signal sequences of preproteins.