Asymmetric adjustment of retail gasoline prices in turkey to world crude oil price changes: the role of taxes

We empirically investigate the impact of shocks to world crude oil prices on retail gasoline prices in Turkey during the 1991-2007 period. Using a Structural-VAR methodology and monthly frequency data, we report that Turkish retail gasoline prices respond significantly to increasing world crude oil prices, but not to decreases. During the estimation period, 70 to 80% of the retail gasoline price was attributable to taxes which were subject to frequent changes by the council of ministers. Although historical data on gasoline taxes is not publicly available, based on the importance of taxes on gasoline price formation in Turkey, we argue that the source of asymmetry is mainly attributable to government price setting policy choice for gasoline. Based on the observed asymmetry from empirical analysis, we further argue that rather than smoothing the impact of volatility in world crude oil prices on Turkish retail gasoline prices, the Turkish fiscal authorities attempted to maximize tax revenue from gasoline.Retail gasoline prices, Rockets and feathers hypothesis, Emerging markets, Fiscal policy, SVAR, Retail diesel oil prices

Oil Prices, aggregate economic activity and global liquidity conditions: evidence from Turkey

When compared to the previous literature which analyzes oil price changes and real economic activity for countries influencing world demand and/or supply, this study is first of its kind in investigating the relation within the context of a small open economy, Turkey. Parallel to the results of Blanchard and Gali (2007) for developed economies, we first report for Turkey that the negative response of real output to oil price increases have diminished since the early 2000s. Other than using different versions of oil price changes and real output growth, which are the standard variables used in the empirical literature, in our next set of estimations we also include variables to account for global liquidity conditions. Once these variables are incorporated, we unveil that the negative impact of oil price changes on aggregate economic activity is significant even in the post-2000 period.

Fundamental properties of solar-like oscillating stars from frequencies of minimum Δν\Delta \nu : II. Model computations for different chemical compositions and mass

The large separations between the oscillation frequencies of solar-like stars are measures of stellar mean density. The separations have been thought to be mostly constant in the observed range of frequencies. However, detailed investigation shows that they are not constant, and their variations are not random but have very strong diagnostic potential for our understanding of stellar structure and evolution. In this regard, frequencies of the minimum large separation are very useful tools. From these frequencies, in addition to the large separation and frequency of maximum amplitude, Y\i ld\i z et al. recently have developed new methods to find almost all the fundamental stellar properties. In the present study, we aim to find metallicity and helium abundances from the frequencies, and generalize the relations given by Y\i ld\i z et al. for a wider stellar mass range and arbitrary metallicity ($Z$) and helium abundance ($Y$). We show that the effect of metallicity is { significant} for most of the fundamental parameters. For stellar mass, for example, the expression must be multiplied by (Z/Z_{\sun})^{0.12}. For arbitrary helium abundance, M \propto (Y/Y_{\sun})^{0.25} . Methods for determination of $Z$ and $Y$ from pure asteroseismic quantities are based on amplitudes (differences between maximum and minimum values of \Dnu) in the oscillatory component in the spacing of oscillation frequencies. Additionally, we demonstrate that the difference between the first maximum and the second minimum is very sensitive to $Z$. It also depends on $\nu_{\rm min1}/\nu_{\rm max}$ and small separation between the frequencies. Such a dependence leads us to develop a method to find $Z$ (and $Y$) from oscillation frequencies. The maximum difference between the estimated and model $Z$ values is about 14 per cent. It is 10 per cent for $Y$.Comment: 8 pages, 13 figures; published in MNRAS (2015

On the structure and evolution of planets and their host stars −- effects of various heating mechanisms on the size of giant gas planets

It is already stated in the previous studies that the radius of the giant planets is affected by stellar irradiation. The confirmed relation between radius and incident flux depends on planetary mass intervals. In this study, we show that there is a single relation between radius and irradiated energy per gram per second ($l_-$), for all mass intervals. There is an extra increase in radius of planets if $l_-$ is higher than 1100 times energy received by the Earth ($l_\oplus$). This is likely due to dissociation of molecules. The tidal interaction as a heating mechanism is also considered and found that its maximum effect on the inflation of planets is about 15 per cent. We also compute age and heavy element abundances from the properties of host stars, given in the TEPCat catalogue (Southworth 2011). The metallicity given in the literature is as [Fe/H]. However, the most abundant element is oxygen, and there is a reverse relation between the observed abundances [Fe/H] and [O/Fe]. Therefore, we first compute [O/H] from [Fe/H] by using observed abundances, and then find heavy element abundance from [O/H]. We also develop a new method for age determination. Using the ages we find, we analyse variation of both radius and mass of the planets with respect to time, and estimate the initial mass of the planets from the relation we derive for the first time. According to our results, the highly irradiated gas giants lose 5 per cent of their mass in every 1 Gyr.Comment: 15 pages, 13 figures, 3 tables. Accepted by MNRA

Statistical (T) rates of convergence

The basis for comparing rates of convergence of two null sequences is that "x = (xn) converges (stat T) faster than z = (zn) provided that (xn/zn) is T-statistically convergent to zero" where T = (tmn) is a mean. In this paper we extend the previously known results either on the ordinary convergence or statistical rates of convergence of two null sequences. We also consider lacunary statistical rates of convergence

Rates of A-statistical convergence of positive linear operators

AbstractIn this paper we study the rates of A-statistical convergence of sequences of positive linear operators mapping the weighted space Cρ1 into the weighted space Bρ2

Asteroseismic Investigation of 20 Planet and Planet-Candidate Host Stars

Planets and planet candidates are subjected to great investigation in recent years. In this study, we analyse 20 planet and planet-candidate host stars at different evolutionary phases. We construct stellar interior models of the host stars with the MESA evolution code and obtain their fundamental parameters under influence of observational asteroseismic and non-asteroseismic constraints. Model mass range of the host stars is 0.74-1.55 ${\rm M}_\odot$. The mean value of the so-called large separation between oscillation frequencies and its variation about the minima show the diagnostic potential of asteroseismic properties. Comparison of variations of model and observed large separations versus the oscillation frequencies leads to inference of fundamental parameters of the host stars. Using these parameters, we revise orbital and fundamental parameters of 34 planets and four planet candidates. According to our findings, radius range of the planets is 0.35-16.50 $\mathrm{R}_{\oplus}$. The maximum difference between the transit and revised radii occurs for Kepler-444b-f is about 25 per cent.Comment: 9 pages, 7 figures, 6 table