Innovation and absorptive capacity: What is the role of technological frontier?

This paper explores how absorptive capacity affects the innovative performance and productivity dynamics of Spanish firms. A firm’s efficiency levels are measured using two variables: the labour productivity and the Total Factor Productivity (TFP). The theoretical framework is based on the seminal contributions of Cohen and Levinthal (1989, 1990) regarding absorptive capacity; and the applied framework is based on the four-stage structural model proposed by Crépon, Duguet and Mairesse (1998) for setting the determinants of R&D, the effects of R&D activities on innovation outputs, and the impacts of innovation on firm productivity. The present study uses a twostage structural model. In the first stage, a probit estimation is used to investigate how the sources of R&D, the absorptive capacity and a vector of the firm’s individual features influence the firm’s likelihood of developing innovations in products or processes. In the second phase, a quantile regression is used to analyze the effect of R&D sources, absorptive capacity and firm characteristics on productivity. This method shows the elasticity of each exogenous variable on productivity according to the firms’ levels of efficiency, and thus allows us to distinguish between firms that are close to the technological frontier and those that are further away from it. We used extensive firm-level panel data from 5,575 firms for the 2004-2009 period. The results show that the internal absorptive capacity has a strong impact on the productivity of firms, whereas the role of external absorptive capacity differs according to nature of the each industry and according the distance of firms from the technological frontier. Key words: R&D sources, innovation strategies, absorptive capacity, technological distance, quantile regression.

The Innovation and Imitation Dichotomy in Spanish firms: do absorptive capacity and the technological frontier matter?

This paper analyses whether a firm’s absorptive capacity and its distance from the technological frontier affect the choice between innovation and imitation in innovative Spanish firms. From an extensive survey of 5,575 firms during the 2004-2009 period, we found two significant results. With regard to the role of absorptive capacity, the empirical evidence shows that when innovative firms have difficulties in accessing external information and hire skilled workers, their innovative capacity is reduced. Meanwhile, with regard to distance from the technological frontier, the firms that reduce this gap manage to increase their innovative capacity at the expense of imitation. To summarise, when we studied firms’ absorptive capacity and their relative position to the technological frontier in tandem, we found that the two factors directly affected firms' ability to innovate or imitate. Key words: R&D sources, innovation and imitation strategies, absorptive capacity, technological frontier, ordered probit.

Replacement therapy for iron deficiency improves exercise capacity and quality of life in patients with cyanotic congenital heart disease and/or the Eisenmenger syndrome

La teràpia suplementària de ferro millora la capacitat d’exercici i la qualitat de vida en malalts amb una cardiopatia congènita cianòtica i/ o síndrome d’Eisenmenger El dèficit de ferro és una troballa comú en la cardiopatia congènita cianòtica, i pot ser la causa d’una reducció en la capacitat d’exercici. Actualment, està indicada la reposició dels dipòsits de ferro en aquest grup de malalts, éssent les evidències científiques escasses. En el present treball investiguem la seguretat i eficàcia del tractament amb ferro en malalts amb una cardiopatia congènita cianòtica. Per tal motiu, vint-i-cinc malalts amb una cardiopatia congenita cianòtica i dèficit de ferro van ser inclosos de forma prospectiva entre Agost del 2008 i Gener del 2009. El tractament utilitzat fou fumarat ferròs oral, fins a una dosi màxima de 200 mg tres vegades al dia. En l’anàlisi basal i als tres mesos de seguiment es va utilitzar el test de qualitat de vida “CAMPHOR”, el test de la marxa dels 6 minuts i la prova d’esforç amb consum d’oxigen. L’edat mitja fou 39.9+/-10.9 anys, 80% dones. Catorze malalts tenien la síndrome d’Eisenmenger, sis una malaltia cianòtica complexa i cinc circulació de Fontan. Cap d’ells va haver d'interrompre el tractament degut a efectes adversos. Després de tres mesos de tractament, l’hemoglobina (19.0+/-2.9g/dL a 20.4+/-2.7g/dL, p&0.001), ferritina (13.3+/-4.7mug/L a 54.1+/-24.2mug/L, p&0.001) i saturació de transferrina (17.8+/-9.6% a 34.8+/-23.4%, p&0.001) van augmentar significativament. També hi va haver una millora significativa en la puntuació del test de qualitat de vida (20.7+/-10.9 a 16.2+/-10.4, p=0.001) i el test de la marxa (371.7+/-84.7m a 402.8.0+/-74.9m, p=0.001). No es van evidenciar canvis significatius en els valors de consum d’oxigen (40.7+/-9.2% a 43.8+/-12.4%, p=0.15). En definitiva, la teràpia suplementària amb ferro en els malats amb una cardiopatia congènita cianòtica i dèficit de ferro és segura i millora la qualitat de vida i la capacitat funcional. En aquest grup de malalts, per tant, és aconsellable identificar el dèficit de ferro i restaurar-ne els seus dipòsits.

Building Capacity in Developing Countries : OER for Food Safety

The Food Safety Knowledge Network (FSKN) was developed through the collaboration of Michigan State University and a professional network of international food industry retailers and manufacturers. The key objective of the FSKN project is to provide technical resources, in a cost effective way, in order to promote food safety in developing countries and for small and less developed companies. FSKN uses a competency based model including a framework, OERs, and assessments. These tools are being used to support face-to-face training, fully online training, and to gauge the learning outcomes of a series of pilot groups which were held in India, Egypt, and China.

Avoiding transcription factor competition at promoter level increases the chances of obtaining oscillations

Background: The ultimate goal of synthetic biology is the conception and construction of genetic circuits that are reliable with respect to their designed function (e.g. oscillators, switches). This task remains still to be attained due to the inherent synergy of the biological building blocks and to an insufficient feedback between experiments and mathematical models. Nevertheless, the progress in these directions has been substantial. Results: It has been emphasized in the literature that the architecture of a genetic oscillator must include positive (activating) and negative (inhibiting) genetic interactions in order to yield robust oscillations. Our results point out that the oscillatory capacity is not only affected by the interaction polarity but by how it is implemented at promoter level. For a chosen oscillator architecture, we show by means of numerical simulations that the existence or lack of competition between activator and inhibitor at promoter level affects the probability of producing oscillations and also leaves characteristic fingerprints on the associated period/amplitude features. Conclusions: In comparison with non-competitive binding at promoters, competition drastically reduces the region of the parameters space characterized by oscillatory solutions. Moreover, while competition leads to pulse-like oscillations with long-tail distribution in period and amplitude for various parameters or noisy conditions, the non-competitive scenario shows a characteristic frequency and confined amplitude values. Our study also situates the competition mechanism in the context of existing genetic oscillators, with emphasis on the Atkinson oscillator.

Impact of antenna correlation on the capacity of multiantenna channels

This paper applies random matrix theory to obtain analytical characterizations of the capacity of correlated multiantenna channels. The analysis is not restricted to the popular separable correlation model, but rather it embraces a more general representation that subsumesmost of the channel models that have been treated in the literature. For arbitrary signal-to-noise ratios (SNR), the characterization is conducted in the regime of large numbers of antennas. For the low- and high-SNR regions, in turn, we uncover compact capacity expansions that are valid for arbitrary numbers of antennas and that shed insight on how antenna correlation impacts the tradeoffs between power, bandwidth and rate.

Capacity-achieving input covariance for single-user multi-antenna channels

We characterize the capacity-achieving input covariance for multi-antenna channels known instantaneously at the receiver and in distribution at the transmitter. Our characterization, valid for arbitrary numbers of antennas, encompasses both the eigenvectors and the eigenvalues. The eigenvectors are found for zero-mean channels with arbitrary fading profiles and a wide range of correlation and keyhole structures. For the eigenvalues, in turn, we present necessary and sufficient conditions as well as an iterative algorithm that exhibits remarkable properties: universal applicability, robustness and rapid convergence. In addition, we identify channel structures for which an isotropic input achieves capacity.

Capacity-approaching rate function for layered multiantenna architectures

The simultaneous use of multiple transmit and receive antennas can unleash very large capacity increases in rich multipath environments. Although such capacities can be approached by layered multi-antenna architectures with per-antenna rate control, the need for short-term feedback arises as a potential impediment, in particular as the number of antennas—and thus the number of rates to be controlled—increases. What we show, however, is that the need for short-term feedback in fact vanishes as the number of antennas and/or the diversity order increases. Specifically, the rate supported by each transmit antenna becomes deterministic and a sole function of the signal-to-noise, the ratio of transmit and receive antennas, and the decoding order, all of which are either fixed or slowly varying. More generally, we illustrate -through this specific derivation— the relevance of some established random CDMA results to the single-user multi-antenna problem.

Capacity to within one bit of a class of Gaussian multicast channels with interference

This paper studies the fundamental operational limits of a class of Gaussian multicast channels with an interference setting. In particular, the paper considers two base stations multicasting separate messages to distinct sets of users. In the presence of channel state information at the transmitters and at the respective receivers, the capacity region of the Gaussian multicast channel with interference is characterized to within one bit. At the crux of this result is an extension to the multicast channel with interference of the Han-Kobayashi or the Chong-Motani-Garg achievable region for the interference channel.

Asymptotic capacity of static multiuser channels with an unknown number of users

We examine a multiple-access communication system in which multiuser detection is performed without knowledge of the number of active interferers. Using a statistical-physics approach, we compute the single-user channel capacity and spectral efficiency in the large-system limit.

Incorporating waiting time in competitive location models: formulations and heuristics

In this paper we propose a metaheuristic to solve a new version of the Maximum Capture Problem. In the original MCP, market capture is obtained by lower traveling distances or lower traveling time, in this new version not only the traveling time but also the waiting time will affect the market share. This problem is hard to solve using standard optimization techniques. Metaheuristics are shown to offer accurate results within acceptable computing times.

State capacity and military conflict

In 1500, Europe was composed of hundreds of statelets and principalities, with weak central authority,no monopoly over the legitimate use of violence, and overlapping jurisdictions. By 1800, only ahandful of powerful, centralized nation states remained. We build a model that explains both the emergenceof capable states and growing divergence between European powers. We argue that the impactof war was crucial for state building, and depended on: i) the financial cost of war, and ii) a country sinitial level of domestic political fragmentation. We emphasize the role of the "Military Revolution",which raised the cost of war. Initially, this caused more cohesive states to invest in state capacity, whilemore divided states rationally dropped out of the competition, causing divergence between Europeanstates. As the cost of war escalated further, all states engaged in a "race to the top" towards greater statebuilding.

Market versus limit orders in an imperfectly competitive security

This paper analyzes the choice between limit and market orders in animperfectly competitive noisy rational expectations economy. There is a uniqueinsider, who takes into account the effect their trading has on prices. If theinsider behaves as a price taker, she will choose market orders if her privateinformation is very precise and she will choose limit orders otherwise. On thecontrary, if the insider recognizes and exploits her ability to affect themarket price, her optimal choice is to place limit orders whatever the precisionof her private information.

Competitive location and pricing on networks

In this paper we consider a location and pricing model for a retail firm that wants to enter a spatial market where a competitor firm is already operating as a monopoly with several outlets. The entering firms seeks to determine the optimal uniform mill price and its servers' locations that maximizes profits given the reaction in price of the competitor firm to its entrance. A tabu search procedure is presentedto solve the model together with computational experience.