Consumption and habits : evidence from panel data

The purpose of this paper is to test for the presence of habit formation in consumption decisions using household panel data. We use the test proposed by Meghir and Weber (1996) and estimate the within -period marginal rate of substitution between commodities, which is robust to the presence of liquidity constraints. To that end, we use a Spanish panel data set in which households are observed up to eight consecutive quarters. This temporal dimension is crucial, since it allows us to take into account time invariant unobserved heterogeneity across households ("fixed effects") and, therefore, to investigate if the relationship between current and past consumption reflects habits or heterogeneity. Our results conf irm the importance of accounting for fixed effects when analyzing intertemporal consumption decisions allowing for time non-separabilities. Once fixed effects are controlled for and a proper set of instruments is used, the results yield supporting evidence of habit formation in the demand system of food at home, transport and services

Unemployment and Inflation Persistence in Spain: Are There Phillips Trade-Offs?

This paper studies the dynamic behavior of inflation and unemployment in Spain during the period 1964?1997. In particular, we analyze the implications of high persistence in both unemployment and inflation dynamics for inference regarding the size of Phillips trade-offs and sacrifice ratios in the Spanish economy, in response to a demand shock. To do so we use a Stuctural VAR approach with several identification outlines which give rise to alternative interpretations of the joint unemployment-inflation dynamics. When using a bivariate VAR we cannot reject the existence of a permanent output loss of one-half of one percentage point for each percentage point of permanent disinflation. However, when the VAR is augmented with a third variable, in order to disentangle monetary from non-monetary shocks within the demand class, the evidence favours a lower and marginally permanent trade-off with an output loss of about one-fourth of one percentage point.Publicad

Resurrection of the sea pen genus Ptilella Gray, 1870 and description of Ptilella grayi n. sp. from the NE Atlantic (Octocorallia: Pennatulacea)

The order Pennatulacea covers a group of specialized and morphologically distinct octocorals found in all oceans from intertidal areas to more than 6000 m in depth. Sea pens constitute an important structural component in marine soft-bottom communities by increasing the complexity of these environments. Despite being both morphologically distinctive and ecologically important, the taxonomy and systematics of sea pens is still poorly understood. Recent molecular studies have shown the existence of convergent morphological features, making the current familial distribution of genera unstable. The genus Pennatula Linnaeus, 1758 was one of the first described octocoral genera. It is the type genus of its family, Pennatulidae. Colonies of this genus have a characteristic morphology. Recent sampling efforts in the northeastern Atlantic have provided a number of colonies initially attributable to the genus Pennatula. Both morphological and molecular (mtMutS, Cox1 and 28S genes) study of this material supports the polyphyletic nature of this genus and the need to resurrect the genus Ptilella Gray, 1870 to accommodate these and other species. A new species, Ptilella grayi n. sp., is described and illustrated. The species Pennatula bayeri is proposed to be a junior synonym of Pennatula bellissima (here also considered in the genus Ptilella)

Low pO2 selectively inhibits K channel activity in chemoreceptor cells of the mammalian carotid body

Producción CientíficaThe hypothesis that changes in environmental 02 tension (pOi) could affect the ionic conductances of dissociated type I cells of the carotid body was tested. Cells were subjected to whole-cell patch clamp and ionic currents were recorded in a control solution with normal pO 2 (pO~ = 150 mmHg) and 3-5 min after exposure to the same solution with a lower pO,. Na and Ca currents were unaffected by lowering pO, to 10 mmHg, however, in all cells studied (n = 42) exposure to hypoxia produced a reversible reduction of the K current. In 14 cells exposed to a pO 2 of 10 mmHg peak K current amplitude decreased to 35 +_ 8% of the control value. The effect of low pO2 was independent of the internal Ca 2+ concentration and was observed in the absence of internal exogenous nucleotides. Inhibition of K channel activity by hypoxia is a graded phenomenon and in the range between 70 and 120 mmHg, which includes normal pO, values in arterial blood, it is directly correlated with pO 2 levels. Low pO2 appeared to slow down the activation time course of the K current but deactivation kinetics seemed to be unaltered. Type I cells subjected to current clamp generate large Na- and Cadependent action potentials repetitively. Exposure to low pO~ produces a 4-10 mV increase in the action potential amplitude and a faster depolarization rate of pacemaker potentials, which leads to an increase in the firing frequency. Repolarization rate of individual action potentials is, however, unaffected, or slightly increased. The selective inhibition of K channel activity by low pO, is a phenomenon without precedents in the literature that explains the chemoreceptive properties of type I cells. The nature of the interaction of molecular O, with the K channel protein is unknown, however, it is argued that a hemoglobin-like O, sensor, perhaps coupled to a G protein, could be involved

Ionic currents in dispersed chemoreceptor cells of the mammalian carotid body

Producción CientíficaIonic currents of enzymatically dispersed type 1 and type 11 cells of the carotid body have been studied using the whole cell variant of the patch-clamp technique. Type 11 cells only have a tiny, slowly activating outward potassium cur­ rent. By contrast, in every type 1 chemoreceptor cell studied we found (a) sodium, (b) calcium, and (e) potassium currents. (a) The sodium current has a fast activation time course and an activation threshold at --40 mV. At ali voltages inactivation follows a single exponential time course. The time constant of inactivation is 0.67 ms at O mV. Half steady state inactivation occurs at a membrane potential of --50 mV. (b) The calcium current is almost totally abolished when most of the extemal calcium is replaced by magnesium. The activation threshold of this cur­ rent is at --40 mV and at O mV it reaches a peak amplitude in 6-8 ms. The calcium current inactivates very slowly and only decreases to 27% of the maximal value at the end of 300-ms pulses to 40 mV. The calcium current was about two times larger when barium ions were used as charge carriers instead of calcium ions. Barium ions also shifted 15-20 mV toward negative voltages the conductance vs. voltage curve. Deactivation kinetics of the calcium current follows a biphasic time course well fitted by the sum of two exponentials. At -80 mV the slow com­ ponent has a time constant of 1.3 ± 0.4 ms whereas the fast component, with an amplitude about 20 times larger than the slow component, has a time constant of 0.16 ± 0.03 ms. These results suggest that type 1 cells have predominantly fast deactivating calcium channels. The slow component of the tails may represent the activity of a small population of slowly deactivating calcium channels, although other possibilities are considered. (e) Potassium current seems to be mainly due to the activity of voltage-dependent potassium channels, but a small percentage of calcium-activated channels may also exist. This current activates slowly, reaches a peak amplitude in 5-1O ms, and thereafter slowly inactivates. Inactivation is almost complete in 250-300 ms. The potassium current is reversibly blocked by tetraeth­ ylammonium. Under current-clamp conditions type I cells can spontaneously fire large action potentials

CONSUMPTION AND HABITS: EVIDENCE FROM PANEL DATA

The purpose of this paper is to test for the presence of habit formation in consumption decisions using household panel data. We use the test proposed by Meghir and Weber (1996) and estimate the within -period marginal rate of substitution between commodities, which is robust to the presence of liquidity constraints. To that end, we use a Spanish panel data set in which households are observed up to eight consecutive quarters. This temporal dimension is crucial, since it allows us to take into account time invariant unobserved heterogeneity across households (“fixed effects”) and, therefore, to investigate if the relationship between current and past consumption reflects habits or heterogeneity. Our results conf irm the importance of accounting for fixed effects when analyzing intertemporal consumption decisions allowing for time non-separabilities. Once fixed effects are controlled for and a proper set of instruments is used, the results yield supporting evidence of habit formation in the demand system of food at home, transport and services.

The Sustainable Management of Metals: An Analysis of Global Research

The objective of this study was to analyze research trends in the field of sustainable management of metals on a global level between 1993 and 2017. To do so, a bibliometric analysis was carried out on a total of 6967 articles. The results revealed the growing interest in this research field, particularly over the last five year-period during which 63% of all articles were published. The three journals in which most articles had been published were the Journal of Cleaner Production, ACS Sustainable Chemistry and Engineering, and Chemsuschem. The countries that published the most articles were China, the United States, India, Germany, and the United Kingdom. A sizeable network of collaboration has been established between countries for the joint publication of studies. The main lines of research have been focused on metal decontamination in water and soil, waste management oriented towards reuse and recycling, and the innovation of processes for cleaner and more efficient production. The results revealed the need for comprehensive studies that integrate different disciplines within the same analytical framework, and to promote research that contributes to the different dimensions of sustainability (environmental, economic, and social)