Absolute and relative deprivation and the measurement of poverty

This paper develops the link between poverty and inequality by focussing on a class of poverty indices (some of them well-known) which aggregate normative concerns for absolute and relative deprivation. The indices are distinguished by a parameter that captures the ethical sensitivity of poverty measurement to ``exclusion'' or ``relative-deprivation'' aversion. We also show how the indices can be readily used to predict the impact of growth on poverty. An illustration using LIS data finds that he United States show more relative deprivation than Denmark and Belgium whatever the percentiles considered, but that overall deprivation comparisons of the four countries considered will generally necessarily depend on the intensity of the ethical concern for relative deprivation. The impact of growth on poverty is also seen to depend on the presence of and on the attention granted to concerns over relative deprivation. }

Persistent bundles over a two dimensional compact set

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

Reliable and persistent storage for CoDeS a distributed collaborative system

This research is aimed to find a solution for a distributed storage system adapted for CoDeS. By studying how DSSs work and how they are implemented, we can conclude how we can implement a DSS compatible with CoDeS requirements.

Mean first-passage times for systems driven by equilibrium persistent-periodic dichotomous noise

In a recent paper, [J. M. Porrà, J. Masoliver, and K. Lindenberg, Phys. Rev. E 48, 951 (1993)], we derived the equations for the mean first-passage time for systems driven by the coin-toss square wave, a particular type of dichotomous noisy signal, to reach either one of two boundaries. The coin-toss square wave, which we here call periodic-persistent dichotomous noise, is a random signal that can only change its value at specified time points, where it changes its value with probability q or retains its previous value with probability p=1-q. These time points occur periodically at time intervals t. Here we consider the stationary version of this signal, that is, equilibrium periodic-persistent noise. We show that the mean first-passage time for systems driven by this stationary noise does not show either the discontinuities or the oscillations found in the case of nonstationary noise. We also discuss the existence of discontinuities in the mean first-passage time for random one-dimensional stochastic maps.

Generalization of the persistent random walk to dimensions greater than 1

We propose a generalization of the persistent random walk for dimensions greater than 1. Based on a cubic lattice, the model is suitable for an arbitrary dimension d. We study the continuum limit and obtain the equation satisfied by the probability density function for the position of the random walker. An exact solution is obtained for the projected motion along an axis. This solution, which is written in terms of the free-space solution of the one-dimensional telegraphers equation, may open a new way to address the problem of light propagation through thin slabs.

Are R&D collaborative agreements persistent at the firm level? Empirical evidence for the Spanish case

We provide evidence on the dynamics in firms’ R&D cooperation behaviour. Our main objective is to analyse if R&D collaborative agreements are persistent at the firm level, and in such a case, to study what are the main drivers of this phenomenon. R&D cooperation activities at the firm level can be persistent due to true state dependence, this implying that cooperating in a given period enhances the probability of doing it in the subsequent period and it can also be a consequence of firms’ individual heterogeneity, so that certain firms have certain characteristics that make them more likely to carry out technological alliances.

Are R&D collaborative agreements persistent at the firm level? Empirical evidence for the Spanish case

We provide evidence on the dynamics in firms’ R&D cooperation behaviour. Our main objective is to analyse if R&D collaborative agreements are persistent at the firm level, and in such a case, to study what are the main drivers of this phenomenon. R&D cooperation activities at the firm level can be persistent due to true state dependence, this implying that cooperating in a given period enhances the probability of doing it in the subsequent period and it can also be a consequence of firms’ individual heterogeneity, so that certain firms have certain characteristics that make them more likely to carry out technological alliances.

Confirmation of persistent radio jets in the microquasar LS 5039

We present here new observations conducted with the EVN and MERLIN of the persistent microquasar LS 5039 discovered by Paredes et al. (2000) with the VLBA. The new observations confirm the presence of an asymmetric two-sided jet reaching up to 1000 AU on the longest jet arm. The results suggest a bending of the jets with increasing distance from the core and/or precession. The origin and location of the high-energy gamma-ray emission associated with the system is discussed and an estimate of the magnetic field at the base of the jet given. Our results suggest a well collimated radio jet. We also comment on new observing strategies to be used with satellites and forthcoming detectors, since this persistent source appears to be a rather good laboratory to explore the accretion/ejection processes taking place near compact objects.

Discovery of a High-Energy Gamma-Ray-Emitting Persistent Microquasar

Microquasars are stellar x-ray binaries that behave as a scaled down version of extragalactic quasars. The star LS 5039 is a new microquasar system with apparent persistent ejection of relativistic plasma at a 3 kiloparsec distance from the sun. It may also be associated with a gamma-ray source discovered by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the COMPTON-Gamma Ray Observatory satellite. Before the discovery of LS 5039, merely a handful of microquasars had been identified in the Galaxy, and none of them was detected in high-energy gamma-rays.

Persistent random walk model for transport trough thin slabs

We present a model for transport in multiply scattering media based on a three-dimensional generalization of the persistent random walk. The model assumes that photons move along directions that are parallel to the axes. Although this hypothesis is not realistic, it allows us to solve exactly the problem of multiple scattering propagation in a thin slab. Among other quantities, the transmission probability and the mean transmission time can be calculated exactly. Besides being completely solvable, the model could be used as a benchmark for approximation schemes to multiple light scattering.

Expressional regulation of key hepatic enzymes of intermediary metabolism in European seabass (Dicentrarchus labrax) during food deprivation and refeeding

We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction)while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.

Expressional regulation of key hepatic enzymes of intermediary metabolism in European seabass (Dicentrarchus labrax) during food deprivation and refeeding

We hypothesized that the analysis of mRNA level and activity of key enzymes in amino acid and carbohydrate metabolism in a feeding/fasting/refeeding setting could improve our understanding of how a carnivorous fish, like the European seabass (Dicentrarchus labrax), responds to changes in dietary intake at the hepatic level. To this end cDNA fragments encoding genes for cytosolic and mitochondrial alanine aminotransferase (cALT; mALT), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were cloned and sequenced. Measurement of mRNA levels through quantitative real-time PCR performed in livers of fasted seabass revealed a significant increase in cALT (8.5-fold induction)while promoting a drastic 45-fold down-regulation of PK in relation to the levels found in fed seabass. These observations were corroborated by enzyme activity meaning that during food deprivation an increase in the capacity of pyruvate generation happened via alanine to offset the reduction in pyruvate derived via glycolysis. After a 3-day refeeding period cALT returned to control levels while PK was not able to rebound. No alterations were detected in the expression levels of G6PDH while 6PGDH was revealed to be more sensitive specially to fasting, as confirmed by a significant 5.7-fold decrease in mRNA levels with no recovery after refeeding. Our results indicate that in early stages of refeeding, the liver prioritized the restoration of systemic normoglycemia and replenishment of hepatic glycogen. In a later stage, once regular feeding is re-established, dietary fuel may then be channeled to glycolysis and de novo lipogenesis.