Use of satellite images for broad-scale modelling of conservation areas for wolves in the Carpathian Mountains, central Europe

This study analysed the spatial structure of the Carpathian Mountains, in Central Europe, considering it a unit that extends across national boundaries, and assessing the suitability of areas were wolves could be conserved. Physical characteristics of the area were extracted from NOAA-AVHRR NDVI. A set of 9 images from different periods of the year was used to parameterise the phenological variability of the area. Digital maps of road networks, human settlements and a DEM were integrated in a GIS. Locations of wolf presence were used to extract “optimal” environmental characteristics that served as reference for estimating the degree of suitability over the whole area. Results show that most of the Carpathian Mountains are highly suitable for the wolf and that highly suitable areas are actually inhabited by the present population of wolf. These are also the area most phenologically stable

Ideology And Influence Balancing Conservative And Neoconservative Power In The Islamic Republic Of Iran

The evolution of the Pasdaran over the past thirty years has brought the group further away from its original role as a protector of the revolution and closer to a parallel, if not competing, economic, political and social institution. In the last decade, conflict dominating the political landscape of the Islamic Republic of Iran has shifted from being defined primarily by the Reformists (Islamic Left) and the Conservatives (Islamic Right), to a multi-dimensional struggle between the Reformists, Conservatives, and Neo-Conservatives, represented by the IRGC and President Ahmadinejad. The IRGC‘s defiance against the authority of the clerics, evidenced by President Ahmadinejad‘s deteriorating relationship with the Supreme Leader, is an indication of a shift in the sources of influence in domestic and foreign policy making and the necessary attempts of the ruling regime to compensate for its loss of control. It appears that the IRGC may be in a position to seriously challenge the authority of the clerics; however, this research hypothesizes that as the organization has evolved parallel to the velayet-e faqih, it does not have the necessary autonomy or cohesion to effectively usurp the rule of the clerics. This study proposes that the competitive disunity that has propelled the growth of the IRGC over the past three decades is prohibitive of the collective consolidation of influence necessary to wrest authority from the clerical regime

Globular Clusters in the Magellanic Clouds.I:BV CCD-Photometry for 11 Clusters

We present BV CCD-data for 11 intermediate-age LMC clusters; the main conclusions are: 1. in the (V_to, V_cl,m) and (V-to, (V_to-V_cl,m)) planes the models yield a good overall description of the data; 2. with the current sample, it is impossible to firmly choose between "classical" and "overshooting" models; 3. the separation in colour between the MS band and the Red He-burning Clump is smaller than predicted by theoretical tracks; 4. the existence of the so-called "RGB phase-transition (Renzini and Buzzoni 1986) seems to be confirmed.Comment: 62 pages, 37 figures and tables 6 to 16 available on request, uuencoded compressed postscript file with tables 1-5 and 17-18 included, BAP 08-1994-020-OA

Realized covariance tick-by-tick in presence of rounded time stamps and general microstructure effects

This paper presents two classes of tick-by-tick covariance estimators adapted to the case of rounding in the price time stamps to a frequency lower than the typical arrival rate of tick prices. Through Monte Carlo simulations, we investigate the behavior of such estimators under realistic market microstructure conditions analogous to those of the financial data examined in this paper's empirical section, that is, nonsynchronous trading, general ARMA structure for microstructure noise, and true lead–lag cross-covariance. Simulation results show the robustness of the proposed tick-by-tick covariance estimators to time stamp rounding, and their overall performance is superior to competing covariance estimators under empirically realistic microstructure conditions. These results are confirmed in the empirical application where the economic benefits of the proposed estimators are evaluated with volatility timing strategies applied to a bivariate portfolio of S&P 500 futures and 30-year U.S. treasury bond futures

Threshold bipower variation and the impact of jumps on volatility forecasting

This study reconsiders the role of jumps for volatility forecasting by showing that jumps have a positive and mostly significant impact on future volatility. This result becomes apparent once volatility is separated into its continuous and discontinuous components using estimators which are not only consistent, but also scarcely plagued by small sample bias. With the aim of achieving this, we introduce the concept of threshold bipower variation, which is based on the joint use of bipower variation and threshold estimation. We show that its generalization (threshold multipower variation) admits a feasible central limit theorem in the presence of jumps and provides less biased estimates, with respect to the standard multipower variation, of the continuous quadratic variation in finite samples. We further provide a new test for jump detection which has substantially more power than tests based on multipower variation. Empirical analysis (on the S&P500 index, individual stocks and US bond yields) shows that the proposed techniques improve significantly the accuracy of volatility forecasts especially in periods following the occurrence of a jump

A Bayesian High-Frequency Estimator of the Multivariate Covariance of Noisy and Asynchronous Returns

A multivariate positive definite estimator of the integrated covariance matrix of noisy and asynchronously observed asset returns is proposed. We adopt a Bayesian Dynamic Linear Model where microstructure noise is interpreted as measurement error, and asynchronous trading as missing observations in an otherwise synchronous series. Missing observations are treated as any other parameter, as typical in a Bayesian framework. An augmented Gibbs algorithm is used since all full conditionals are available and its convergence and robustness are discussed. A realistic simulation study compares our estimator with existing alternatives, under different liquidity and microstructure noise conditions. The results suggest that our estimator is superior in terms of RMSE particularly under severe conditions, such as portfolios of assets with heterogeneous liquidity and high level of microstructure noise. The application to the empirical dataset of ten tick-by-tick stock price series confirms the simulation results

Measuring the propagation of financial distress with Granger-causality tail risk networks

Using the test of Granger-causality in tail of Hong et al. (2009), we define and construct Granger-causality tail risk networks between 33 systemically important banks (G-SIBs) and 36 sovereign bonds worldwide. Our purpose is to exploit the structure of the Granger-causality tail risk networks to identify periods of distress in financial markets and possible channels of systemic risk propagation. Combining measures of connectedness of these networks with the ratings of the sovereign bonds, we propose a flight-to-quality indicator to identify periods of turbulence in the market. Our measure clearly peaks at the onset of the European sovereign debt crisis, signaling the instability of the financial system. Finally, we use the connectedness measures of the networks to forecast the quality of sovereign bonds. We find that connectedness is a significant predictor of the cross-section of bond quality