The Two Active X Chromosomes in Female ESCs Block Exit from the Pluripotent State by Modulating the ESC Signaling Network

During early development of female mouse embryos, both X chromosomes are transiently active. X gene dosage is then equalized between the sexes through the process of X chromosome inactivation (XCI). Whether the double dose of X-linked genes in females compared with males leads to sex-specific developmental differences has remained unclear. Using embryonic stem cells with distinct sex chromosome compositions as a model system, we show that two X chromosomes stabilize the naive pluripotent state by inhibiting MAPK and Gsk3 signaling and stimulating the Akt pathway. Since MAPK signaling is required to exit the pluripotent state, differentiation is paused in female cells as long as both X chromosomes are active. By preventing XCI or triggering it precociously, we demonstrate that this differentiation block is released once XX cells have undergone X inactivation. We propose that double X dosage interferes with differentiation, thus ensuring a tight coupling between X chromosome dosage compensation and development

Reflectivity Anisotropy Spectra of Cu- and Ag- (110) surfaces from {\it ab initio} theory

We are able to disentagle the effects of the intraband and interband parts of the bulk dielectric function on the bare dielectric anisotropy of the surface. We show how the position, sign and amplitude of the structures observed in such spectra depend on the above quantities. The lineshape of all the calculated structures agree very well with the ones observed experimentally for samples treated by suitable surface cleaning. In particular, we reproduce the observed single peak structure of Ag at high energy, found to represent a state of the clean surface different from the one giving the originally observed double peak structure. This results is not reproduced by the 'local field' model.Comment: 4 pages, 3 figures. submitted to Phys. Rev. Let

Does R&D, human capital and FDI matter for TFP in OECD countries?

This study investigates the interplay between research and development (R&D), human capital (HC), foreign direct investment (FDI) and total factor productivity (TFP) in OECD countries. We divide the sample into two sub-groups; the European and the non-European states so as to account for underlying country heterogeneity. The analysis follows a panel data approach over the period 1995–2015, taking into account the modelling on non-stationarity, long-run relationships and short-run dynamics with a panel VAR. Both R&D and HC have a positive effect on TFP, whilst FDI has a positive and significant effect only in the case of non-European countries. Moreover, the contribution of R&D is higher than that of HC and FDI in all cases. Thus, based on these findings, policymakers should design and implement policies to increase resources invested in R&D, with a consistent ongoing spending review, to attract foreign direct investment, especially for the majority of the European and some of the non-European countries and to improve education system on a more productive innovation and research base

PRIVATE SAVINGS IN TRANSITION ECONOMIES: ARE THERE TERMS OF TRADE SHOCKS?

The paper examines the impact of terms of trade shocks on private savings in the transition economies after accounting for the effect of other determinants. Economic agents in the transition economies are subject to tight credit constraints which are more pronounced during bad state of nature. Thus, adverse shocks to commodity prices in the world market can force them to reduce savings by a larger amount than they would otherwise have. Empirical analysis using a dynamic panel model and data from twenty one transition economies confirm that most of the determinants of savings identified in the literature also apply to the transition economies. Favorable movements in both the permanent and transitory components of the terms of trade have a significant positive impact on private savings with transitory movements having a larger impact than the permanent component. This reflects the lack of access to foreign borrowing that many of the transition economies have faced during the last decade. Although the impact of terms of trade shocks are found to be asymmetric, the magnitude of the impact appears to be small. The results are robust for alternative estimators, determinants, and country groupings.http://deepblue.lib.umich.edu/bitstream/2027.42/39958/3/wp572.pd

The China miracle in a technological and socio-political framework—The role of institutions

China’s economy has grown at an average annual rate of around 9.5% in the past four decades, which is often hailed as the China Miracle. This paper proposes a new theoretical model to analyse the causes of China’s phenomenal growth in a technological and socio-political framework. In our new framework, the contemporary technology (T) determines what an economy can achieve; the objective (O) of the society has a fundamental impact on its economic growth; the performance (P) in implementing the social objective largely determines the growth rate of the economy; and the stability (S) of the society determines the sustainability of the economic growth. China’s institutions have played key roles in the TOPS framework to initiate and sustain China’s rapid growth in the past four decades. Socio-political changes caused by economic growth might affect the capacity of these institutions to promote economic growth in future