The presented paper aims to analyse both statistical and economic aspects of the model with I(2) variables. The statistical foundations of such models are introduced. The enlargement of possible statistical interpretation is discussed. The economic interpretation of both VECM parameters and common stochastic trends representation is considered in the I(2) domain. The returns of I(2) approach in terms of stock-flows, nominal-real analysis and diasggregation into both long-, short and even medium-run analysis are proved. Potential complications under reflecting I(3) variables are presented.

The paper analyses the consequences of structural change in the presenceof non-stationary stochastic processes I(1) or I(2). The structural change mayconcern the deterministic structure (in particular, the trend and the constantterm) as well as the process generating the stochastic part. The focus of thepaper is on the case of a discrete change in a regime for which the momentof switch is known. A change in the deterministic part does not alter thecharacter of the cointegration relationships but its consequences for cotrendingand cobreaking are interesting. The consequences of a change in the stochasticpart are more complex, because then the stochastic process as well as thedeterministic structure of the VECM are modified. The restrictions are analysedfor both cases.

Bayesian VAR (BVAR) models offer a practical solution to the parameter proliferation concerns as they allow to introduce a priori information on seasonality and persistence of inflation in a multivariate framework. We investigate alternative prior specifications in the case of time series with a clear seasonal pattern. In the empirical part we forecast the monthly headline inflation in the Polish economy over the period 2011‒2014 employing two popular BVAR frameworks: a steady-state reduced-form BVAR and just-identified structural BVAR model. To evaluate the forecast performance we use the pseudo real-time vintages of timely information from consumer and financial markets. We compare different models in terms of both point and density forecasts. Using formal testing procedure for density-based scores we provide the empirical evidence of superiority of the steady-state BVAR specifications with tight seasonal priors.

This paper discusses the challenges faced by the empirical macroeconomist and methods for surmounting them. These challenges arise due to the fact that macroeconometric models potentially include a large number of variables and allow for time variation in parameters. These considerations lead to models which have a large number of parameters to estimate relative to the number of observations. A wide range of approaches are surveyed which aim to overcome the resulting problems. We stress the related themes of prior shrinkage, model averaging and model selection. Subsequently, we consider a particular modelling approach in detail. This involves the use of dynamic model selection methods with large TVP-VARs. A forecasting exercise involving a large US macroeconomic data set illustrates the practicality and empirical success of our approach.

This paper investigates the relative importance of cost, demand, financialand monetary shocks in driving real exchange rates in four CEE countries over2000–2018. A two-country New Keynesian open economy model is used as atheoretical framework. In the empirical part, a Bayesian SVAR model withMarkov switching heteroscedasticity is employed. The structural shocks areidentified on the basis of volatility changes and named with reference to the signrestrictions derived from the economic model. Main findings are fourfold. First,real and financial shocks have similar contributions to real exchange variability,whereas that of monetary shocks is small. Second, financial shocks amplifyexchange rate fluctuations stemming from real shocks. Third, even though theexchange rate gaps change over time, they remain quite similar across CEEcountries except for Slovakia. Fourth, Slovakia introduced the euro at the timeof a relatively large real overvaluation, which subsided after a lengthy adjustmentprocess.

The model considered in the paper is defined as VAR with the prior distribution for parameters generated by the dynamic stochastic general equilibrium (DSGE) model. The degree of economic restrictions in the DSGE-VAR model is controlled by the weighting parameter. In the paper there is investigated the impact of the weighting parameter prior specifications for the posterior shape of impulse response functions (IRFs). In case of conditional models the paths of IRFs highly depend on the value of the weighting parameter that is set arbitrary. When considering full estimation with different prior types, means and gradual change in the dispersion the posterior time paths of IRFs are similar in models with high values of the marginal data density.

Allium cepa var. agrogarum L. seedlings grown in nutrient solution were subjected to increasing concentrations of Cd2+ (0, 1, 10, 100 μM). Variation in tolerance to cadmium toxicity was studied based on chromosome aberrations, nucleoli structure and reconstruction of root tip cells, Cd accumulation and mineral metabolism, lipid peroxidation, and changes in the antioxidative defense system (SOD, CAT, POD) in leaves and roots of the seedlings. Cd induced chromosome aberrations including C-mitoses, chromosome bridges, chromosome fragments and chromosome stickiness. Cd induced the production of some particles of argyrophilic proteins scattered in the nuclei and even extruded from the nucleoli into the cytoplasm after a high Cd concentration or prolonged Cd stress, and nucleolar reconstruction was inhibited. In Cd2+-treated Allium cepa var. agrogarum plants the metal was largely restricted to the roots; very little of it was transported to aerial parts. Adding Cd2+ to the nutrient solution affected mineral metabolism. For example, at 100 μM Cd it reduced the levels of Mn, Cu and Zn in roots, bulbs and leaves. Malondialdehyde content in roots and leaves increased with treatment time and increased concentration of Cd. Antioxidant enzymes appear to play a key role in resistance to Cd under stress conditions.

We investigated direct and indirect formation of somatic embryogenesis in Brassica oleracea var. botrytis (cauliflower), a very important vegetable crop worldwide. Direct somatic embryogenesis, which is rather rare, was achieved in culture of 2-week-old hypocotyl explants of Brassica oleracea var. botrytis on MS medium supplemented with 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5; 1.0; and 1.5 mg/l kinetin. Initial induction of embryogenic callus was achieved on MS supplemented with very low concentrations of 2,4-D (0.05 mg/l and 0.1 mg/l). Indirect somatic embryogenesis from leaf sections was obtained on MS supplemented with 0.05 or 0.1 mg/l 2,4-D. We examined various stages of somatic embryos (globular, heart, torpedo, cotyledonary). More embryos per explant were produced through the indirect pathway (23-25) than through the direct pathway (14-19). The number of embryos produced was high. There is a potential for recurrent, repeated or secondary somatic embryogenesis, possibly an unlimited source for mass propagation and ideal for synthetic seed production in this species. Plant regeneration was achieved on half-strength MS medium without any hormones.