Embedding theorems of function classes, IV

Vegeu el resum a l'inici del document del fitxer adjunt

Endogenous integration and welfare in complementary goods markets

This paper analyzes the strategic decision to integrate by firms that produce complementary products. Integration entails bundling pricing. We find out that integration is privately profitable for a high enough degree of product differentiation, that profits of the non-integrated firms decrease, and that consumer surplus need not necessarily increase when firms integrate despite the fact that prices diminish. Thus, integration of a system is welfare-improving for a high enough degree of product differentiation combined with a minimum demand advantage relative to the competing system. Overall, and from a number of extensions undertaken, we conclude that bundling need not be anti-competitive and that integration should be permitted only under some circumstances.

Mobile termination, network externalities, and consumer expectations

We re-examine the literature on mobile termination in the presence of network externalities. Externalities arise when firms discriminate between on- and off-net calls or when subscription demand is elastic. This literature predicts that profit decreases and consumer surplus increases in termination charge in a neighborhood of termination cost. This creates a puzzle since in reality we see regulators worldwide pushing termination rates down while being opposed by network operators. We show that this puzzle is resolved when consumers' expectations are assumed passive but required to be fulfilled in equilibrium (as defined by Katz and Shapiro, AER 1985), instead of being rationally responsive to non-equilibrium prices, as assumed until now.

Models i mètriques d'estimació d'esforç per la gestió de projectes informàtics.

L'objectiu principal d'aquest treball ha estat buscar i valorar les diferents opcions que hi ha en la gestió de projectes per a estimar-ne els costos relacionats. La primera de les tasques que s'ha fet és definir el terme 'projecte' per esbrinar quins tipus de projectes són susceptibles de ser valorats; aquesta tipificació ha portat a dividir els projectes en dues branques molt diferenciades, tot i que relacionades, durant el seu desenvolupament.

Sistema de validació amb proveïdor deidentitat extern per a serveis de VideoOn Demand

El producte a realitzar es composa de 2 aplicacions web, 1 Web Service i 1applet, tots ells desenvolupats utilitzant la tecnologia J2EE 6.0. S¿ha escollitla versió J2EE de Java, per la facilitat que proporciona perdesenvolupaments web i client-servidor.

Analyzing shapes as compositions of distances

We propose to analyze shapes as “compositions” of distances in Aitchison geometry asan alternate and complementary tool to classical shape analysis, especially when sizeis non-informative.Shapes are typically described by the location of user-chosen landmarks. Howeverthe shape – considered as invariant under scaling, translation, mirroring and rotation– does not uniquely define the location of landmarks. A simple approach is to usedistances of landmarks instead of the locations of landmarks them self. Distances arepositive numbers defined up to joint scaling, a mathematical structure quite similar tocompositions. The shape fixes only ratios of distances. Perturbations correspond torelative changes of the size of subshapes and of aspect ratios. The power transformincreases the expression of the shape by increasing distance ratios. In analogy to thesubcompositional consistency, results should not depend too much on the choice ofdistances, because different subsets of the pairwise distances of landmarks uniquelydefine the shape.Various compositional analysis tools can be applied to sets of distances directly or afterminor modifications concerning the singularity of the covariance matrix and yield resultswith direct interpretations in terms of shape changes. The remaining problem isthat not all sets of distances correspond to a valid shape. Nevertheless interpolated orpredicted shapes can be backtransformated by multidimensional scaling (when all pairwisedistances are used) or free geodetic adjustment (when sufficiently many distancesare used)

Agglomeration-effects in Europe

The paper estimates agglomeration-effects for France, Germany, Italy, Spain, and the UK. Estimation takes into account endogeneity of the spatial distribution ofemployment and spatial fixed-effects. Empirical resultssuggest that agglomeration-effects in these Europeancountries are only slightly smaller than agglomeration-effects in the US: the estimated elasticity of average-labor-productivity with respect to employment-density is 4.5 percent compared to 5 percent in the US.

IFRS introduction and its effect on listed companies in Spain

From the beginning of January 2005 publicly traded companies in the European Union have to comply with the International Financial Reporting Standards (IFRS) for their consolidated accounts, as required by 1606/2002 European Commission Regulation. It had been suggested that the new accounting rules will facilitate not only the process of international harmonization of financial statements, but also efficient performance of financial markets and capital flows worldwide. This study analyzes the first results of IFRS implementation by Spanish non-financial listed companies.

Recursos web per a la classificació

En el número (BiD, núm. 5, desembre 2000) vàrem començar un repàs acurat i per temes de les eines bàsiques de treball per al bibliotecari. Aquest segon recull pretén, selectivament, donar a conèixer alguns treballs (associacions, publicacions, guies, recursos temàtics) lligats amb la classificació i, per extensió, a la indexació. Parlem de classificacions numèriques i alfanumèriques, deixant de banda les llistes d'encapçalament i tesaurus que formaran part d'una nova selecció posterior. Insisteixo que es tracta d'un recull selectiu i no pas exhaustiu (al marge de la selecció de recursos per a les classificacions clàssiques, és a dir, CDU, LCC, Bliss o DDC, les classificacionsgenerades per a especialitats concretes han trobat a Internet una magnífica via de distribució, molt especialment relacionades amb les disciplines cientificotècniques, les ciències de la salut, la literatura grisa i la informàtica i les noves tecnologies del coneixement). Es tracta, en la majoria dels casos, i pel que fa a les classificacions generalistes clàssiques, de guies elaborades per les mateixes biblioteques, de manera més o menys detallada, gairebé com a eines de formació d'usuaris. Un altre grup inclou les classificacions completes, pensades per al maneig del bibliotecari o l'usuari interessat en el món de la classificació i la indexació. Un capítol a part i que per raons òbvies s'ha desenvolupat notòriament aquests darrers anys, són les classificacions com a eina de disposició lògica (generalment jeràrquica)dels recursos localitzables a Internet (sovint adaptacions de la Dewey i molt especialment l'LLC), i, en alguns casos, classificacions pròpies i molt simplificades que parteixen dels principis bàsics de tota classificació: àmbits temàtics i de procedència, i, per als recursos electrònics, tipologia i accessibilitat. La selecció inclou, quan s'ha considerat oportú, uns petits comentaris de contingut i, entre cometes, la traducció d'algunes parts de la presentació del recurs o de comentaris realitzats sobre aquell pels mateixos autors. Per una qüestió simplement d'utilitat, no s'han inclòs referències d'algunes de les classificacions anomenades històriques, és a dir: Classification de Brunet (1810), Baconian Classification (1605), etc. (tot i que es troba informació disponible en xarxa). No s'ha inclòs un apartat exclusiu per a la classificació expansiva perquè es considera que el sistema inventat per Charles A. Cutter (1891) va ser la base i encara ho és de la Library of Congress Classification (especialment pel que fa als "Cutter Numbers").

Effect of meal ingestion on liver stiffness in patients with cirrhosis and portal hypertension.

BACKGROUND AND AIMS: Liver stiffness is increasingly used in the non-invasive evaluation of chronic liver diseases. Liver stiffness correlates with hepatic venous pressure gradient (HVPG) in patients with cirrhosis and holds prognostic value in this population. Hence, accuracy in its measurement is needed. Several factors independent of fibrosis influence liver stiffness, but there is insufficient information on whether meal ingestion modifies liver stiffness in cirrhosis. We investigated the changes in liver stiffness occurring after the ingestion of a liquid standard test meal in this population. METHODS: In 19 patients with cirrhosis and esophageal varices (9 alcoholic, 9 HCV-related, 1 NASH; Child score 6.9±1.8), liver stiffness (transient elastography), portal blood flow (PBF) and hepatic artery blood flow (HABF) (Doppler-Ultrasound) were measured before and 30 minutes after receiving a standard mixed liquid meal. In 10 the HVPG changes were also measured. RESULTS: Post-prandial hyperemia was accompanied by a marked increase in liver stiffness (+27±33%; p<0.0001). Changes in liver stiffness did not correlate with PBF changes, but directly correlated with HABF changes (r = 0.658; p = 0.002). After the meal, those patients showing a decrease in HABF (n = 13) had a less marked increase of liver stiffness as compared to patients in whom HABF increased (n = 6; +12±21% vs. +62±29%,p<0.0001). As expected, post-prandial hyperemia was associated with an increase in HVPG (n = 10; +26±13%, p = 0.003), but changes in liver stiffness did not correlate with HVPG changes. CONCLUSIONS: Liver stiffness increases markedly after a liquid test meal in patients with cirrhosis, suggesting that its measurement should be performed in standardized fasting conditions. The hepatic artery buffer response appears an important factor modulating postprandial changes of liver stiffness. The post-prandial increase in HVPG cannot be predicted by changes in liver stiffness.

Effect of meal ingestion on liver stiffness in patients with cirrhosis and portal hypertension.

BACKGROUND AND AIMS: Liver stiffness is increasingly used in the non-invasive evaluation of chronic liver diseases. Liver stiffness correlates with hepatic venous pressure gradient (HVPG) in patients with cirrhosis and holds prognostic value in this population. Hence, accuracy in its measurement is needed. Several factors independent of fibrosis influence liver stiffness, but there is insufficient information on whether meal ingestion modifies liver stiffness in cirrhosis. We investigated the changes in liver stiffness occurring after the ingestion of a liquid standard test meal in this population. METHODS: In 19 patients with cirrhosis and esophageal varices (9 alcoholic, 9 HCV-related, 1 NASH; Child score 6.9±1.8), liver stiffness (transient elastography), portal blood flow (PBF) and hepatic artery blood flow (HABF) (Doppler-Ultrasound) were measured before and 30 minutes after receiving a standard mixed liquid meal. In 10 the HVPG changes were also measured. RESULTS: Post-prandial hyperemia was accompanied by a marked increase in liver stiffness (+27±33%; p<0.0001). Changes in liver stiffness did not correlate with PBF changes, but directly correlated with HABF changes (r = 0.658; p = 0.002). After the meal, those patients showing a decrease in HABF (n = 13) had a less marked increase of liver stiffness as compared to patients in whom HABF increased (n = 6; +12±21% vs. +62±29%,p<0.0001). As expected, post-prandial hyperemia was associated with an increase in HVPG (n = 10; +26±13%, p = 0.003), but changes in liver stiffness did not correlate with HVPG changes. CONCLUSIONS: Liver stiffness increases markedly after a liquid test meal in patients with cirrhosis, suggesting that its measurement should be performed in standardized fasting conditions. The hepatic artery buffer response appears an important factor modulating postprandial changes of liver stiffness. The post-prandial increase in HVPG cannot be predicted by changes in liver stiffness.