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A Temporal White Noise Analysis for Extracting the Impulse Response Function of the Human ElectroretinogramZele, A., Feigle, B., Kambhampati, P., Aher, A., McKeefry, Declan J., Parry, Neil R.A., Maguire, John, Murray, I.J., Kremers, Jan January 2017 (has links)
Yes / Purpose: We introduce a method for determining the impulse response function (IRF)
of the ERG derived from responses to temporal white noise (TWN) stimuli.
Methods: This white noise ERG (wnERG) was recorded in participants with normal
trichromatic vision to full-field (Ganzfeld) and 39.38 diameter focal stimuli at mesopic
and photopic mean luminances and at different TWN contrasts. The IRF was obtained
by cross-correlating the TWN stimulus with the wnERG.
Results: We show that wnERG recordings are highly repeatable, with good signal-tonoise
ratio, and do not lead to blink artifacts. The wnERG resembles a flash ERG
waveform with an initial negativity (N1) followed by a positivity (P1), with amplitudes
that are linearly related to stimulus contrast. These N1 and N1-P1 components
showed commonalties in implicit times with the a- and b-waves of flash ERGs. There
was a clear transition from rod- to cone-driven wnERGs at ~1 photopic cd.m 2. We
infer that oscillatory potentials found with the flash ERG, but not the wnERG, may
reflect retinal nonlinearities due to the compression of energy into a short time period
during a stimulus flash.
Conclusion: The wnERG provides a new approach to study the physiology of the
retina using a stimulation method with adaptation and contrast conditions similar to
natural scenes to allow for independent variation of stimulus strength and mean
luminance, which is not possible with the conventional flash ERG.
Translational Relevance: The white noise ERG methodology will be of benefit for
clinical studies and animal models in the evaluation of hypotheses related to cellular
redundancy to understand the effects of disease on specific visual pathways.
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A New Approach to Estimate the Incidence of the Corporate Income TaxVasquez-Ruiz, Harold A. 12 April 2012 (has links)
After Harberger published his influential paper in 1962, many authors have assessed empirically whether the incidence of the corporate income tax (CIT) falls on capital owners, consumers, or workers (Krzyzaniak and Musgrave, 1963; Gordon, 1967; Arulampalam et al., 2008). Today, there is little agreement among economists about who bears the incidence of the CIT (Gruber, 2007; Harberger, 2008a,b). The reason for the little convincing evidence is that the econometric models used in the literature ignore that the factors that motivate changes in corporate tax policy are sometimes correlated with other developments in the economy and disentangling those effects from exogenous policy changes requires tremendous effort.
Using annual information at the industry level for the United States, I propose to investigate the consequences of exogenous changes in corporate tax policy. The identification of these exogenous events follows the work of Romer and Romer (2009, 2010), who provide an extensive analysis of the U.S. federal tax legislation using narrative records from presidential speeches and congressional reports, among other documentations.
The results validate the original predictions from Harberger (1995, 2008a). That is, in the short-term, capital owners bear the full burden of the tax. Over time, however, capital owners are able to shift this burden either by raising consumers' goods prices, or decreasing workers' wages. The magnitude of these e ects depends on the degree of capital intensity as well as the access to international markets and the availability of substitutes for the industry under consideration.
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Economic Policy Effect in Quterly-dependence VAR model: Empirical Analysis of Taiwanese casesLiu, Chun-I 30 June 2010 (has links)
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This paper uses a seasonal dependence VAR model that is proposed by Olivei and Tenreyro in the year 2007.We are to assess whether the effect of a policy exogenous shock differs according to the quarter in which the shock occur. We consider Taiwan as a small open economy with flourishing international trade; the effect of exchange rate is viewed as an important transmission channel in monetary transmission mechanism. First part, we consider domestic monetary policy shock how to influence macroeconomic variables. Second part, the United State is powerful around the world. The Fed policies whether affect Taiwan macroeconomic or not. Finally, discuss an exogenous shock on the exchange rate to impact Taiwan macroeconomic.
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The Analysis of Long-run Real Exchange Rate in JapanLiu, Ya-chun 26 July 2010 (has links)
Purchasing Power Parity (PPP) has been regarded as the most important theory to
explain the exchange rate movement based on relative price levels of two countries. After 1973,
more and more countries were taking the floating exchange rate system, and the real exchange
is testing out to be a non-stationary time seriess. This would be some real factors to have an
effect on the real exchange rate. In the article, We study how these possible factors change
the real exchange rate and make use of Wu et.al (2008) and Lee (2010)¡¦s local projection to
estimate the impulse responses under the non-stationary time series which has cointegration
vectors, and then we compare the difference between the impulse response in conventional VAR
and the impulse response in Local Projection. The emprical model we use is the smae one as
in Zhou (1995) and Wang and Dunne (2003), and the rule of the data is the same as in Wang
and Dunne (2003). Finally, we get the consistent conclusion with Wu et.al (2008), Zhou (1995)
and Wang and Dunne (2003).
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The Impulse Response Analysis of General Inference on Cointegration Vector for Non-Stationary Process by Local ProjectionLin, Meng-wei 26 July 2010 (has links)
Jorda (2005) proposed the new method to estimate impulse response functions by local
projection. The new method, local projection, can avoid the misspecification problem. That
is, local projections are robust to misspecification of the data generating process (DGP). Wu,
Lee, and Wang (2008) extended the Jorda¡¦s local projection from stationary time series I(0) to
non-stationary time series I(1). It makes the local projection be a more generally applicative
method for the Macroeconomic. In the article, I relax the cointegration vector which assumed
to be known in the Wu, Lee, and Wang (2008) and Lee(2010). From the inference of Johansen
(1995) I can get the property of super-consistent between £] and ˆ £] in the cointegration vector. I
use the above condition and OLS to estimate impulse response functions, and in the asymptotic
theorem, the cointegration vectors which assumed to be known or estimated by Johansen MLE
are both get the consistent coefficients of impulse responses.
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The Impact of The Monetary Polciy in Taiwan-A FAVAR Model ApproachChu, I-Ching 19 July 2011 (has links)
This paper applies a Factor-Augmented VAR model proposed by Bernanke, Boivin and Eliasz (2005) to measure the impact of the monetary policy in Taiwan. Our empirical results show that, first, the more the factors added in the benchmark VAR, the more we can explain the price puzzle problem. Second, the effect of the tightening in the monetary policy (the increase in the interbank overnight lending rate) is inconsistent with the results expected by the credit channel.
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Agreement of CMIP5 Simulated and Observed Ocean Anthropogenic CO2 UptakeBronselaer, Benjamin, Winton, Michael, Russell, Joellen, Sabine, Christopher L., Khatiwala, Samar 28 December 2017 (has links)
Previous studies found large biases between individual observational and model estimates of historical ocean anthropogenic carbon uptake. We show that the largest bias between the Coupled Model Intercomparison Project phase 5 (CMIP5) ensemble mean and between two observational estimates of ocean anthropogenic carbon is due to a difference in start date. After adjusting the CMIP5 and observational estimates to the 1791-1995 period, all three carbon uptake estimates agree to within 3Pg of C, about 4% of the total. The CMIP5 ensemble mean spatial bias compared to the observations is generally smaller than the observational error, apart from a negative bias in the Southern Ocean and a positive bias in the Southern Indian and Pacific Oceans compensating each other in the global mean. This dipole pattern is likely due to an equatorward and weak bias in the position of Southern Hemisphere westerlies and lack of mode and intermediate water ventilation.
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The financial crisis and household savings in South Africa : An econometric analysis / Itumeleng Pleasure MongaleMongale, Itumeleng Pleasure January 2012 (has links)
The "global" financial crisis (GFC) emerged during 2008 and it was mainly triggered by
the sub-prime mortgage crisis (SMC) in the United States of America. The main aims of
this thesis is to conduct an econometric analysis of the financial crisis and household
savings in South Africa and also to provide a rationale that will facilitate a policy
attention on Domestic Resource Mobilisation (DRM) through household savings. The
study uses quarterly time series data for the period 199401 to 201102 obtained on-line
from the South African Reserve Bank (SARB). The research is based on the Keynesian
saving function, which is a complement of the consumption function. The model will be
estimated by using a cointegrating vector autoregressive (CVAR) framework, which
allows for endogeneity of the regressors. To check robustness on the cointegration
results, the study employs the second empirical technique based on Generalized
Impulse Response Function (GIRF) analysis and Variance Decomposition. The
regression equation of household savings is expressed as a function of household
disposable income, household debt to disposable income, real GOP, interest rate,
inflation rate and foreign savings.
The variables are tested for the presence of a unit root by the application of the
Augmented Dickey-Fuller (AOF), Phillips-Perron (PP) Kwiatkowski, Phillips, Schmidt
and Shin (KPSS) tests. The findings of the study are that all variables have unit roots.
The cointegration model emphasises the presence of a long run equilibrium relationship
between dependent and independent variables. The CVAR reveals the short run of the
dynamic household savings model. Taking this into consideration, the study concludes
that household debt has a huge influence on the level of household savings.
The econometric analysis also revealed that household savings in South Africa actually
improved during the period associated with the GFC. It could be postulated that South
African households responded to their deteriorating financial situations by reducing their
average spending and increasing their savings. Variance decomposition analysis
revealed that 'own shocks' constitute the predominant source of variations in household
saving therefore household savings can be explained by the disturbances in
macroeconomic variables in the study.
The study recommends the promotion of household savings and economic growth in
order to reduce the dependence of South Africa on foreign savings. DRM is therefore
enhanced by a higher level of household savings, which can facilitate higher levels of
investment and economic growth. / Thesis (PhD (Economics) North-West University, Mafikeng Campus, 2012
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Causalidade entre as taxas de crescimento dos paÃses desenvolvidos e emergentes / Causality enters the taxes of growth of the developed and emergent countriesJoÃo Francisco de Souza Filho 08 May 2008 (has links)
AtravÃs da utilizaÃÃo de instrumentais estatÃsticos e economÃtricos para a anÃlise de sÃries temporais, buscou-se verificar as relaÃÃes entre as taxas de crescimento dos
paÃses desenvolvidos e emergentes. Para tanto, utilizou-se de uma amostra contendo a taxa real de crescimento econÃmico desses paÃses no perÃodo de 1970-2007. Com base nesse estudo, verificou-se que existe causalidade, no sentido
Granger, do crescimento econÃmico dos paÃses desenvolvidos em direÃÃo aos paÃses emergentes. A funÃÃo de resposta a impulsos mostrou que a resposta dos paÃses emergentes a choques no crescimento dos paÃses desenvolvidos foi a mais significativa e duradoura. / Through the use of statistical and econometric instrumentals for the analysis of time series, this work aims to verify the relationships between the economic growth rate of
developed and emergent countries. For so much, it was used of a sample containing the real economic growth rate of those countries in the period of 1970-2007. With
base in this study, it was verified that causality exists, in the sense of Granger, of the economic growth rate of the countries developed towards the emerging countries.
The impulse response function showed that the answer of the emerging countries to impacts in the economic growth of the developed countries was the most significant and durable.
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Do crude oil price changes affect economic growth of India, Pakistan and Bangladesh? : A multivariate time series analysisAkram, Muhammad January 2012 (has links)
This paper analyzes empirically the effect of crude oil price change on the economic growth of Indian-Subcontinent (India, Pakistan and Bangladesh). We use a multivariate Vector Autoregressive analysis followed by Wald Granger causality test and Impulse Response Function (IRF). Wald Granger causality test results show that only India’s economic growth is significantly affected when crude oil price decreases. Impact of crude oil price increase is insignificantly negative for all three countries during first year. In second year, impact is negative but smaller than first year for India, negative but larger for Bangladesh and positive for Pakistan.
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