Luis F. Martins

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Neurogenesis and apoptosis occur contemporaneously in the postnatal hippocampal dentate gyrus and have been implicated in mood and cognitive disorders. Particularly, neurogenesis correlates with the manifestation of antidepressant effects, but its quantitative and topographical relationship with concomitant cell death has not been investigated. Accordingly,(More)
Differentiation of the presynaptic terminal is a complex and rapid event that normally occurs in spatially specific axonal regions distant from the soma; thus, it is believed to be dependent on intra-axonal mechanisms. However, the full nature of the local events governing presynaptic assembly remains unknown. Herein, we investigated the involvement of the(More)
We study the determinants of Credit Default Swap (CDS) spreads through quantile regressions. In addition to traditional variables, the results indicate that CDS spreads are also determined by illiquidity costs. However, contrary to stocks or bonds, we show that CDS transaction costs should be measured by absolute, rather than relative, bid-ask spreads.(More)
Understanding the mechanisms that regulate postnatal neurogenesis is becoming increasingly relevant since its modulation has been implicated in the pathogenesis of certain neuropsychiatric disorders. Lithium is a mood stabilizer known to increase hippocampal neurogenesis. Lithium also results in increased levels of the angiogenic factor vascular endothelial(More)
In this paper, we examine parameter identi…cation in the hybrid speci…cation of the New Keynesian Phillips Curve proposed by Gali and Gertler (1999). We employ recently developed moment-conditions inference procedures, which provide a more e¢ cient and reliable econometric framework for the analysis of the NKPC. In particular, we address the issue of(More)
In this paper we propose an approach to detect persistence changes in fractionally integrated models based on recursive forward and backward estimation of the Breitung and Hassler (2002) test. This procedure generalises to fractionally integrated processes the approaches of Leybourne, Kim, Smith and Newbold (2003) and Leybourne and Taylor (2003), which are(More)
Model averaging (MA) estimators in the linear instrumental variables regression framework are considered. The obtaining of weights for averaging across individual estimates by direct smoothing of selection criteria arising from the estimation stage is proposed. This is particularly relevant in applications in which there is a large number of candidate(More)
International equity markets linkages are characterized by nonlinear dependence and asymmetries. We investigate shifts in long run comovements in stock markets by means of an ‘interrupted’ Markov switching cointegration specification. This flexible approach allow us to study to what extent documented changes in global integration are permanent, or whether(More)