10 documents found, page 1 of 1
Synaptogenesis Stimulates a Proteasome-Mediated Ribosome Reduction in Axons
Costa, Rui O.; Martins, Helena; Martins, Luís F.; Cwetsch, Andrzej W; Mele, Miranda; Pedro, Joana R.; Tomé, Diogo; Jeon, Noo Li; Cancedda, LauraRibosomes and a subset of cellular mRNAs are trafficked into axons of developing neurons. The axonal localization of translational machinery allows new proteins to be rapidly and locally synthesized during axonal growth and pathfinding. However, in mature neurons, axonal ribosomes are significantly reduced or even absent. The mechanism that elicits this removal is currently unknown. Here, we demonstrate that sy...
Digital collection creator, visualizer and explorer
Martins, Luís F.; Araújo, Cristiana; Henriques, Pedro RangelIn this paper we introduce and discuss a recent project, called CortaColaEspia, aimed at extending with some extra relevant features the’Ontology-based Collection Processor’ developed previously in the context of a Compilers course. The basic processor, based on the OntoDL tool, was able to read the ontological description of a small collection of objects (cards, pencils, toys, etc.) and produce automatically a...
Mesenchymal stem cells secretome-induced axonal outgrowth is mediated by BDNF
Martins, Luís F.; Costa, Rui O.; Pedro, Joana R.; Aguiar, Paulo; Serra, Sofia C.; Teixeira, Fabio G.; Sousa, Nuno; Salgado, António J.Mesenchymal stem cells (MSCs) have been used for cell-based therapies in regenerative medicine, with increasing importance in central and peripheral nervous system repair. However, MSCs grafting present disadvantages, such as, a high number of cells required for transplantation and low survival rate when transplanted into the central nervous system (CNS). In line with this, MSCs secretome which present on its c...
Mesenchymal stem cells secretome-induced axonal outgrowth is mediated by BDNF
Martins, Luís F.; Costa, Rui O.; Pedro, Joana R.; Aguiar, Paulo; Serra, Sofia Cravino; Teixeira, Fábio Gabriel Rodrigues; Sousa, Nuno; Salgado, A. J.Mesenchymal stem cells (MSCs) have been used for cell-based therapies in regenerative medicine, with increasing importance in central and peripheral nervous system repair. However, MSCs grafting present disadvantages, such as, a high number of cells required for transplantation and low survival rate when transplanted into the central nervous system (CNS). In line with this, MSCs secretome which present on its c...
Linear instrumental variables model averaging estimation
Martins, Luís F.; Gabriel, Vasco Joaquim Cruz Ricardo AssunçãoModel 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 instruments and, therefore, a considerable number of instrum...
Piezoresistive accelerometer produced by microinjection moulding
Martins, Luís F.; Rocha, Luís A.; Pontes, A. J.The miniaturization of parts is an essential step in the evolution of technology, where more functions are integrated in less space. Therefore in recent years there is a growing interest in microsystems due to the number of possible applications in several different areas. This paper describes a different approach to the production of one of these devices, a piezoresistive accelerometer. The main structure of t...
Cointegration tests under multiple regime shifts : an application to the stock ...
Gabriel, Vasco J.; Martins, Luís F.We examine the properties of several residual-based cointegration tests when long run parameters are subject to multiple shifts driven by an unobservable Markov process. Unlike earlier work, which considered one-off deterministic breaks, our approach has the advantage of allowing for an unspecified number of stochastic breaks. We illustrate this issue by exploring the possibility of Markov switching cointegrati...
The cost channel reconsidered : a comment using an identification-robust approach
Gabriel, Vasco J.; Martins, Luís F.We re-examine the empirical relevance of the cost channel of monetary policy (e.g. Ravenna and Walsh, 2006), employing recently developed moment-conditions inference methods, including identification-robust procedures. Using US data, our results suggest that the cost channel effect is poorly identified and we are thus unable to corroborate the previous results in the literature.
The forecast performance of long memory and Markov switching models
Gabriel, Vasco J.; Martins, Luís F.Recent research has focused on the links between long memory and structural change, stressing the long memory properties that may arise in models with parameter changes. In this paper, we contribute to this research by comparing the forecasting abilities of long memory and Markov switching models. Two approaches are employed: a Monte Carlo study and an empirical comparison, using the quarterly Consumer Price in...
The properties of cointegration tests in models with structural change
Gabriel, Vasco J.; Martins, Luís F.In this paper we examine, by means of Monte Carlo simulation, the properties of several cointegration tests when long run parameters are subject to structural changes. We allow for different types of stochastic and deterministic regime shifts, more specifically, changes governed by Markov chains, martingale parameter variation, sudden multiple breaks and gradual changes. Our Monte Carlo analysis reveals that te...