1. |
|
|
2. |
|
|
3. |
|
|
4. |
|
|
5. |
- Pertl, Leonhard, et al.
(author)
-
Exports and Productivity : Comparable Evidence for 14 Countries
- 2007
-
In: Policy Research Working Papers. - New York : World Bank. - 1813-9450.
-
Reports (peer-reviewed)abstract
- The authors use comparable micro level panel data for 14 countries and a set of identically specified empirical models to investigate the relationship between exports and productivity. The overall results are in line with the big picture that is by now familiar from the literature: Exporters are more productive than non-exporters when observed and unobserved heterogeneity are controlled for, and these exporter productivity premia tend to increase with the share of exports in total sales; there is strong evidence in favour of self-selection of more productive firms into export markets, but nearly no evidence in favour of the learning-by-exporting hypothesis. The authors document that the exporter premia differ considerably across countries in identically specified empirical models. In a meta-analysis of their results the authors find that countries that are more open and have more effective government report higher productivity premia. However, the level of development per se does not appear to be an explanation for the observed cross-country differences.
|
|
6. |
- Vilar, M, et al.
(author)
-
Ligand-independent signaling by disulfide-crosslinked dimers of the p75 neurotrophin receptor
- 2009
-
In: Journal of cell science. - : The Company of Biologists. - 1477-9137 .- 0021-9533. ; 122:18Pt 18, s. 3351-3357
-
Journal article (peer-reviewed)abstract
- Dimerization is recognized as a crucial step in the activation of many plasma membrane receptors. However, a growing number of receptors pre-exist as dimers in the absence of ligand, indicating that, although necessary, dimerization is not always sufficient for signaling. The p75 neurotrophin receptor (p75NTR) forms disulfide-linked dimers at the cell surface independently of ligand binding through Cys257 in its transmembrane domain. Here, we show that crosslinking of p75NTR dimers by cysteine-scanning mutagenesis results in constitutive, ligand-independent activity in several pathways that are normally engaged upon neurotrophin stimulation of native receptors. The activity profiles of different disulfide-crosslinked p75NTR mutants were similar but not identical, suggesting that different configurations of p75NTR dimers might be endowed with different functions. Interestingly, crosslinked p75NTR mutants did not mimic the effects of the myelin inhibitors Nogo or MAG, suggesting the existence of ligand-specific activation mechanisms. Together, these results support a conformational model of p75NTR activation by neurotrophins, and reveal a genetic approach to generate gain-of-function receptor variants with distinct functional profiles.
|
|