Renaissance of a rural artifact in a city with a million people: biodiversity responses to an agro-forestry restoration in a large urban traditional fruit orchard

The rural landscapes surrounding large cities are rapidly becoming incorporated into the urban environment. The most conspicuous changes involve green spaces, such as former agro-forestry systems like fruit orchards. In this paper, we assess the influence on biodiversity of restoring a large urban traditional fruit orchard as reflected by six selected taxa: plants, lichens, butterflies, beetles, orthopteroids and birds. The study was performed in Prague, which is the capital city of the Czech Republic and has more than a million inhabitants. We studied the effect of orchard renewal in 45 patches (15 for birds and 30 for other taxa). The majority of taxa responded positively to the restoration. The restoration had a significant positive effect on the species richness of lichens, butterflies and beetles. All taxa showed significantly altered species compositions, and the number of red-listed species increased. Orchards have a high potential for multi-functional use. Orchards are productive agro-forestry systems and host numerous possible human activities. Therefore, orchard restoration also has a social aspect. Moreover, our research in this artificial ecosystem revealed that its restoration increased the biodiversity and conservation potential of the associated areas.

     

Strategies for a sequential selection of the better of two trinomial populations

A sequential procedure for a selection of the better of two trinomial populations has been proposed by ?idók (1988). The present paper shows some Monte Carlo results for 4 different strategies of sequential experimentation in this procedure, on this basis compares the strategies, and gives some practical recommendations for choosing the strategy.     

Betriebsinterne Arbeitsmärkte, Hierarchien und Neueinstellungen: Eine empirische Untersuchung mit Personaldaten

Many empirical studies which deal with internal labour markets are related to the work of Doeringer and Piore (1971). The majority of these studies cannot find closed internal labour markets with entry positions at the lower end of a firm’s hierarchy. Most of these studies, however, use data from financial and service industries, managerial or other white-collar workers. Doeringer and Piore (1971) state that closed internal labour markets with clearly defined entry positions should be found especially for blue-collar workers in the manufacturing industry, because firm specific human capital is of large importance in these industries. In this paper, a large data set of a manufacturing company with blue-collar and white-collar workers is used. We show that the internal labour market of blue-collar workers is more closed than that of white-collar workers. Moreover, we find that firm specific human capital plays a major role in determining the hierarchical position of blue-collar workers. Entries of white-collar workers, however, appear at all hierarchical positions. Furthermore, formal education plays a major role in allocating the white-collar workers.     

Passive Support: No Support at All?

Several scholars have pointed out a shift from classic secondary associations to tertiary organizations based on passive support in Western countries. This development necessitates a better understanding of passive support within social science and voluntary sector management, on which strong opinions are expressed in the literature. This article attempts to contribute to the empirical basis for such opinions. We suggest that the current anxieties concerning the future of democracy if activity rates drop may be exaggerated.     

Value-at-risk estimation with new skew extension of generalized normal distribution

In this paper, we introduce a new distribution, called the alpha-skew generalized normal (ASGN), for GARCH models in modeling daily Value-at-Risk (VaR). Basic structural properties of the proposed distribution are derived including probability and cumulative density functions, moments and stochastic representation. The real data application based on ISE-100 index is given to show the performance of GARCH model specified under ASGN innovation distribution with respect to normal, Student’s-t, skew normal and generalized normal models in terms of the VaR accuracy. The empirical results show that GARCH model with ASGN innovation distribution generates the most accurate VaR forecasts for all confidence levels.     

Darling-Erdös-type test for change detection in parameters and variance for stationary VAR models

The aim of this article is the construction of the test statistic for the detection of changes in vector autoregressive (AR) models where both AR parameters and the variance matrix of the error term are the subjects of a change. The approximating distribution of the proposed statistic is the Gumbel distribution. The proof stands on the approximation of weakly dependent random vectors by independent ones and by application of Horváth’s extension of Darling-Erdös extremal result for random vectors, see Darling and Erdös (1956) Darling, D.A., Erdös, P. (1956). A limit theorem for the maximum of normalized sums of independent random variables. Duke Math. J. 23:143–155.[Crossref], [Web of Science ®] , [Google Scholar] and Horváth (1993) Horváth, L. (1993). The maximum likelihood method for testing changes in the parameters of normal observations. Ann. Stat. 21(2):671–680.[Crossref], [Web of Science ®] , [Google Scholar]. The test statistic is a modification of the likelihood ratio.     

Modeling and forecasting persistent financial durations

This article introduces the Markov-Switching Multifractal Duration (MSMD) model by adapting the MSM stochastic volatility model of Calvet and Fisher (2004) to the duration setting. Although the MSMD process is exponential β-mixing as we show in the article, it is capable of generating highly persistent autocorrelation. We study, analytically and by simulation, how this feature of durations generated by the MSMD process propagates to counts and realized volatility. We employ a quasi-maximum likelihood estimator of the MSMD parameters based on the Whittle approximation and establish its strong consistency and asymptotic normality for general MSMD specifications. We show that the Whittle estimation is a computationally simple and fast alternative to maximum likelihood. Finally, we compare the performance of the MSMD model with competing short- and long-memory duration models in an out-of-sample forecasting exercise based on price durations of three major foreign exchange futures contracts. The results of the comparison show that the MSMD and the Long Memory Stochastic Duration model perform similarly and are superior to the short-memory Autoregressive Conditional Duration models.     

Understanding the links among innovation performance,market performance and financial performance

Innovation and its impacts on business performance are strategically vital deliberations for modern business organizations. In this study, we examine how innovation performance affects two different facets of firm performance: market performance and financial performance. Many studies address the relationship between innovation and business performance, but few empirical studies analyze the interplay between those variables. Research results reveal a suppression effect of market performance on the innovation–financial performance relationship. We find a negative direct relationship between innovation and financial performance; however, market performance reverses this negative effect to a positive total influence through its suppression effect. This result indicates the vital role of market performance in converting innovation to positive financial outcomes. The proposed mediation model is relevant regardless of the set of firm-level and environmental contingency variables.