141 research outputs found
Runx Expression Is Mitogenic and Mutually Linked to Wnt Activity in Blastula-Stage Sea Urchin Embryos
The Runt homology domain (Runx) defines a metazoan family of sequence-specific transcriptional regulatory proteins that are critical for animal development and causally associated with a variety of mammalian cancers. The sea urchin Runx gene SpRunt-1 is expressed throughout the blastula stage embryo, and is required globally during embryogenesis for cell survival and differentiation.Depletion of SpRunt-1 by morpholino antisense-mediated knockdown causes a blastula stage deficit in cell proliferation, as shown by bromodeoxyuridine (BrdU) incorporation and direct cell counts. Reverse transcription coupled polymerase chain reaction (RT-PCR) studies show that the cell proliferation deficit is presaged by a deficit in the expression of several zygotic wnt genes, including wnt8, a key regulator of endomesoderm development. In addition, SpRunt-1-depleted blastulae underexpress cyclinD, an effector of mitogenic Wnt signaling. Blastula stage cell proliferation is also impeded by knockdown of either wnt8 or cyclinD. Chromatin immunoprecipitation (ChIP) indicates that Runx target sites within 5′ sequences flanking cyclinD, wnt6 and wnt8 are directly bound by SpRunt-1 protein at late blastula stage. Furthermore, experiments using a green fluorescent protein (GFP) reporter transgene show that the blastula-stage operation of a cis-regulatory module previously shown to be required for wnt8 expression (Minokawa et al., Dev. Biol. 288: 545–558, 2005) is dependent on its direct sequence-specific interaction with SpRunt-1. Finally, inhibitor studies and immunoblot analysis show that SpRunt-1 protein levels are negatively regulated by glycogen synthase kinase (GSK)-3.These results suggest that Runx expression and Wnt signaling are mutually linked in a feedback circuit that controls cell proliferation during development
Do dividends signal future earnings in the Nordic stock markets?
We study the informational content of dividends on three Nordic civil law markets, where other simultaneous but blurring motives for dividends may be weaker. Using aggregate data on real earnings per share and payout ratios, long time series from 1969 to 2010, and methodologies which address problems of endogeneity, non-stationarity and autocorrelation (including a Vector Error Correction Model approach), we find evidence on dividend signaling in Nordic markets. However, we also find heterogeneity in the relationship between dividends and earnings on markets similar in many respects, suggesting that even small variations in the institutional surroundings may be important for the results
Efficiency Of Foreign Exchange Markets: A Developing Country Perspective
This study tests weak and semi-strong form efficiency of the foreign exchange market in
Sri Lanka during the recent float using six bilateral exchange rates. Weak-form efficiency
is examined using unit root tests while semi-strong form efficiency is tested using cointegration, Granger causality tests and variance decomposition analysis. Results
indicate that the Sri Lankan foreign exchange market is consistent with the weak-form of
the efficient market hypothesis (EMH). However, the results provide evidence against the
semi-strong version of the EMH. These results have important implications for
government policy makers and participants in the foreign exchange market of Sri Lank
EFEITOS DA POLÍTICA DE SALÁRIO MÍNIMO SOBRE O MERCADO DE TRABALHO METROPOLITANO: UMA ANÁLISE EMPÍRICA A PARTIR DE VETORES AUTORREGRESSIVOS (VAR) - (2003-2015)
RESUMO Com intuito de verificar os efeitos que a política de salário mínimo exerce sobre o mercado de trabalho metropolitano brasileiro, o presente estudo contribui ao verificar a sua inter-relação com variáveis como taxa de atividade, grau de informalidade e taxa de desemprego em quatro regiões metropolitanas (Recife, Porto Alegre, Belo Horizonte e São Paulo), separadamente, no período de janeiro de 2003 a março de 2015. Ao utilizar o método de autorregressão vetorial (VAR), os resultados mostram que a relação entre salário mínimo e taxa de atividade se deu com ingresso de mão de obra apenas em uma região estudada. Nas demais regiões observam-se tanto uma tendência de queda no grau de informalidade quanto um aumento na taxa de desemprego
Expectations and Uncertainty: A Common-Source Infection Model for Selected European Countries
We present a common-source infection model for explaining the formation of expectations by households. Starting from the framework of "Macroeconomic expectations of household and professional forecasters" (C.D. Carroll, The Quarterly Journal of Economics, 2003), we augment the original model assuming that also uninformed individuals are able to update expectations according to a naive econometric process. In this novel framework, a key role is played by the parameter measuring the prob- ability of being informed: the dynamics of this factor over time capture the level of uncertainty perceived by households. This new framework is applied to study unemployment expectations for a selected group of European countries (France, Germany, Italy and the UK). Our results show that: (i) the novel framework is supported by data on unemployment expectations; and (ii) the probability of being informed is (negatively) correlated with the level of uncertainty spread by newspapers and conveyed by Internet
Cointegration analysis with state space models
Abstract: This paper presents and exemplifies results developed for cointegration analysis with state space models by Bauer and Wagner in a series of papers. Unit root processes, cointegration and polynomial cointegration are defined. Based upon these definitions the major part of the paper discusses how state space models, which are equivalent to VARMA models, can be fruitfully employed for cointegration analysis. By means of detailing the cases most relevant for empirical applications, the I(1), MFI(1) and I(2) cases, a canonical representation is developed and thereafter some available statistical results are briefly mentioned.
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