Volatility persistence is a stylized statistical property of financial time-series data such as exchange rates and stock returns. The purpose of this letter is to investigate the relationship between volatility persistence and predictability of squared returns.

The aim of the present study was to determine the content of polycyclic aromatic hydrocarbons in relation to the intensity and type of soil management. Two types of soil were selected for the present studies, i.e.: Haplic Phaeozem developed from loess and Eutric Fluvisol originating from silty formations. Five objects were chosen in cach of the soils included in the present study, i.e.: apple orchards, hop gardens, arabic fields, grassland and natural forest ecosystems. Samples were collected from the depth of 0-1 O, I 0- 20 and below 35 cm. In the study material obtained, the content of 16 PAHs was determined by means of the HPLC-UV method. The content of polycyclic aromatic hydrocarbons clearly depended both on the soil type and soil management method. Only in the case of two objects (hop garden and grassland plot) both the Haplic Phaeozem and the Eutric Fluvisol were characterized by the highest PAH content. The influence of soil management method on both the PAH sum and the content of individual compounds was more clearly marked in the Haplic Phaeozem than in the Eutric Fluvisol. PAH migration deeper into the soil profile similarly to their content depended on the soil type and soil management method. However, both in the Eutric Fluvisol and in the Haplic Phaeozem, an increase in naphthalene share was observed with a decrease in depth. Nevertheless, the effect of pollutant leaching deeper into the soil profile was more clearly marked in the case of Eutric Fluvisol.

Ability of five strains of Trichoderma pseudokoningii (antagonists) to suppress radial growth of Fusarium verticillioides (Sacc.) Nirenberg (= Fusarium moniliforme Sheldon) was examined in vitro These were T. pseudokoningii strai n1 (IMI 380933), strain 2 (IMI 380937), strain 3 (IMI 3809 39), strain 4 (IMI 380940) a nd strain 5 (IMI 380941). Each strain was paired with pathogen by inoculating at opposite ends of 9 cm petri plates using three pairing methods. Gradings were assigned to varied growth inhibition of pathogen by antagonists and analysed using GLM procedure (SAS). Growth suppression of F. verticillioides by all strains of T. pseudokoningii was significantly different (R² = 0.98, p = 0.05) from control in all pairing methods. It differed significantly (p > 0.0003) among the strains in all pairing methods. Growth suppression also differed significantly among (p>0.0001) and within (p > 0.018) pairing methods. Growth suppression was best when antagonists were inoculated before pathogen. Suppression mechanisms include mycoparasitism and competition for space and nutrients. T. pseudokoningii strains 3 and 4 had the best (p = 0.05) growth suppression of F. verticillioides and could be used as biocontrol agents for endophytic F. verticillioides in maize plant. This experiment was conducted in the search for resedent microorganisms that might be capable of checking F. verticillioides within maize plant by competitive exclusion in subsequent experiment.

In the present paper changes of polycyclic aromatic hydrocarbons (PAHs) content were evaluated during composting of sewage sludge stabilized with coal fly ash. The content of PAHs in sewage sludge used for composting was I 0385 μg/kg (±830). In fly ash only three PAHs were determined (phenanthrene - 0.9 μg/kg, anthraccnc - 1.9 μg/kg and chrysenc - 2.7 μg/kg). Addition of fly ash to composted sewagesludge had various - dependent on its share - effect on PAHs mineralization. Relatively best degradation (66.3%) was noted when sewage sludge was mixed with fly ash in amount 20% (w/w). In composted sewage sludge and sludge with 30% addition of fly ash a decrease of PAH content was also observed (38 and 32.4% respectively). Relatively "best" mineralization was noted for 3-ring PAHs. Estimated half-lives of all investigated compounds depended on individual PAHs properties and ranged from 59 to 1164 days.

The hedonic tone of an environmental odor is a powerful predictor of annoyance. Pertinent field surveys combined with laboratory analysis of landfill, pharmaceutical factories and rubber factories have been conducted, with the purpose of obtaining a behavior curve of the hedonic tone for specific odor emissions, and comparing the annoyance potential and odor persistence of the sources under investigation. The 9-point scale was used to determine the hedonic tone, and the odor concentration was measured using the Triangle Odor Bag Method. The concentration to be presented to panel members comprises a range of 5 or 6 dilution steps which differ by a factor of approximately 3. Using a suitable curve fitting procedure, a line can be fitted through the points obtained in the experiment. Characteristic H values at any concentration can be derived from the hedonic behavior curve. The relationship between the hedonic tone and lgOC conforms to the quadratic polynomial for the three sources. The persistence of odor is expressed as a dose (concentration) response and (intensity) function. According to the rate of change in odor intensity, the pharmaceutical odor is the strongest, followed by the landfill odor, and then the rubber odor. Annoyance potential is calculated by multiplying lgOC with the max hedonic value, meaning that the three sources are sorted as follows: rubber factory>landfill>pharmaceutical factory. This study will further the understanding of the sensory characteristics of different odor source

Dynamic Mine disasters can be induced by the instability and failure of a composite structure of rock and coal layers during coal mining. Coal seam contains many native defects, severely affecting the instability and failure of the compound structure. In this study, the effects of coal persistent joint on the strength and failure characteristics of coal-rock composite samples were evaluated using PFC2D software. The results show that with the increase of included angle α between the loading direction and joint plane direction, the uniaxial compressive stress (UCS) and peak strain of composite samples first decrease and then gradually increase. The elastic moduli of composite samples do not change obviously with α. The peak strain at α of 45° is the lowest, and the UCS at α of 30° is the smallest. This is inconsistent with theoretical analysis of lowest UCS at α of 45°. This is because that the local stress concentration caused by the motion inconformity of composite samples may increase the average axial stress of upper wall in PFC2D software. Moreover, the coal persistent joint promotes the transformation from the unstable crack expansion to the macro-instability of composite samples, especially at α of 30° and 45°. The majority of failures for composite samples occur within the coal, and no obvious damage is observed in rock. Their failure modes are shear failure crossing or along the coal persistent joint. The failure of composite sample at α of 30° is a mixed failure, including the shear failure along the persistent joint in coal and tensile failure of rock induced by the propagation of coal persistent joint.