1,010 research outputs found

    The effect of soil risk element contamination level on the element contents in Ocimum basilicum L.

    Get PDF
    Red basil (Ocimum basilicum L.) cv. Red Rubin was cultivated in model pot experiment in the soil amended by arsenic, cadmium and lead solutions in stepwise concentrations representing the soil concentration levels of former mining area in the vicinity of Příbram, Czech Republic. The element levels added to the soil reached up to 40 mg Cd, 100 mg As, and 2000 mg Pb per kg of soil. Moreover, essential macro-and microelements as well as cyanidine contents were investigated to assess their potential interactions with the risk elements. The extractable element portions in soils determined at the end of vegetation period differed according to the individual elements. Whereas the plant-available (extractable with 0.11M CH3COOH) content of Cd represented 70-100% of the added Cd, the mobile portion of Pb did not exceed 1%. The risk element content in plants reflected the increasing element contents in soil. The dominant element portions remained in plant roots indicating the limited translocation ability of risk elements to the aboveground biomass of this plant species. Although the risk element contents in amended plants significantly increased, no visible symptoms of phytotoxicity occurred. However, the effect of enhanced risk element contents on the essential element uptake was assessed. Considering inter-element relationships, elevated sulphur levels were seen in amended plants, indicating its possible role of phytochelatin synthesis in the plants. Moreover, the molybdenum contents in plant biomass dropped down with increasing risk element uptake by plants confirming As-Mo and Cd-Mo antagonism. The increasing content of cyanidine in the plant biomass confirmed possible role of anthocyanins in detoxification mechanism of risk element contaminated plants and suggested the importance of anthocyanin pigments for risk element tolerance of plants growing in contaminated areas

    Boundary value problems for the mildly non-linear ordinary differential equation of the fourth order

    Get PDF
    summary:In this paper, the finite difference method is applied to a boundary value problem for the mildly non-linear ordinary differential equation of the fourth order. The existence of a unique solution of both the differential and the difference problem is proved and an O(h2)O(h^2) estimate of the discretization error and its first difference quotient is derived. Some numerical examples are given

    Data boxes in public administration

    Get PDF
    Data boxes are currently a very popular discussion topic and this especially considering the communications between public administration and the private sector being done through them. Due to the fact that the data boxes have been introduced recently and that legislation allows exceptions for their use, a number of challenging issues arise in this respect and obstacles to reach the principal goal for which the data boxes have been introduced. Not only exceptions in the legislation but as well the low level of knowledge in this field, on the part of the public-at-large as well as the users of data boxes themselves, leads to a erroneous manipulation with data messages and thus creates difficulties which can have dramatic consequences. The purpose of this article is to provide a broad overview about data boxes with an emphasis on related problems, especially in the field of public administration and to suggest possible solutions

    Riccati matrix differential equation and the discrete order preserving property

    Get PDF
    summary:In this paper we recall discrete order preserving property related to the discrete Riccati matrix equation. We present results obtained by applying this property to the solutions of the Riccati matrix differential equation

    Systems of differential equations modeling non-Markov processes

    Get PDF
    summary:The work deals with non-Markov processes and the construction of systems of differential equations with delay that describe the probability vectors of such processes. The generating stochastic operator and properties of stochastic operators are used to construct systems that define non-Markov processes

    Recording fine‐scale movement of ground beetles by two methods: Potentials and methodological pitfalls

    Get PDF
    Movement trajectories are usually recorded as a sequence of discrete movement events described by two parameters: step length (distance) and turning angle (bearing). One of the most widespread methods to record the geocoordinates of each step is by a GPS device. Such devices have limited suitability for recording fine movements of species with low dispersal ability including flightless carabid beetles at small spatio‐temporal scales. As an alternative, the distance‐bearing approach can avoid the measurement error of GPS units since it uses directly measured distances and compass azimuths. As no quantification of measurement error between distance‐bearing and GPS approaches exists so far, we generated artificial fine‐scale trajectories and in addition radio‐tracked living carabids in a temperate forest and recorded each movement step by both methods. Trajectories obtained from distance‐bearing were compared to those obtained by a GPS device in terms of movement parameters. Consequently, both types of trajectories were segmented by state‐switching modeling into two distinct movement stages typical for carabids: random walk and directed movement. We found that the measurement error of GPS compared to distance‐bearing was 1.878 m (SEM = 0.181 m) for distances and 31.330° (SEM = 2.066°) for bearings. Moreover, these errors increased under dense forest canopy and rainy weather. Distance error did not change with increasing distance recorded by distance‐bearing but bearings were significantly more sensitive to error at short distances. State‐switching models showed only slight, not significant, differences in movement states between the two methods in favor of the random walk in the distance‐bearing approach. However, the shape of the GPS‐measured trajectories considerably differed from those recorded by distance‐bearing caused especially by bearing error at short distances. Our study showed that distance‐bearing could be more appropriate for recording movement steps not only of ground‐dwelling beetles but also other small animals at fine spatio‐temporal scales

    Riccati inequality and other results for discrete symplectic systems

    Get PDF
    AbstractIn this paper we establish several new results regarding the positivity and nonnegativity of discrete quadratic functionals F associated with discrete symplectic systems. In particular, we derive (i) the Riccati inequality for the positivity of F with separated endpoints, (ii) a characterization of the nonnegativity of F for the case of general (jointly varying) endpoints, and (iii) several perturbation-type inequalities regarding the nonnegativity of F with zero endpoints. Some of these results are new even for the special case of discrete Hamiltonian systems

    Habitat mosaic of gravel pit as a potential refuge for carabids: a case study from Central Europe

    Get PDF
    Abstract In gravel pits, a mosaic of habitats with various environmental conditions created during mining has a great potential for persistence of many species. We focused on such a mosaic in a gravel pit surrounded by agricultural landscape. We investigated which habitats within sludge deposits in different successional stages (from bare sands to secondary forest) and agriculturally reclaimed area enhanced diversity, species richness and abundance of carabids and supported occurrence of threatened species. Since some of these habitats were extensively managed while others were invaded by the alien plant Solidago gigantea, we also tested the effect of management and the cover of S. gigantea on carabid assemblages. We found a gradient in carabid assemblages from psammophilous ones in bare sandy soils towards similar assemblages in plots with well-developed vegetation cover. Here, carabid assemblages were represented predominantly by common species of agricultural and forest lands without higher habitat requirements. Contrarily, plots with bare sand could serve as a refuge for rare psammophilous carabid species, which cannot occur in surrounding landscape due to vanished suitable habitats. Therefore, keeping some of habitats in early plant successional states is important for maintaining habitat mosaic and for persistence of such species as well. Management of grasslands and cover of S. gigantea had no effect on carabid assemblage. We presume that carabids were likely more affected by vegetation structure and density than species composition

    Beetles on the move: Not‐just‐a‐technical review of beetles' radio‐tracking

    Get PDF
    Radio telemetry with very high-frequency transmitters is a powerful tool for studying the movement patterns of animals. Although this tracking technology is widely utilized for various vertebrates, its application is limited to only a fraction of large-bodied insect species. Among them, beetles are the most popular insect group used for radio-tracking due to their relatively large body size, solid exoskeleton, and to some extent the well-known ecological background of some species. Here, we review the available literature about radio telemetry applied to beetles, focusing on current methodological advantages and constraints to record their movement, as well as how this method can assist in understanding various ecological aspects of beetle life history. Regardless of the huge potential of radio-tracking, the number of tracked beetle species is still very low, covering so far only 13 species belonging to five families that were studied almost exclusively in the Western Palearctic region. Most studies were descriptive, measuring simple trajectory parameters and examining movement behavior as a single strategy that is not triggered by any particular internal or external cues. Ecological aspects have been accessed to a lesser extent, especially in relation to the effects of abiotic factors and habitat use. There are still conceptual knowledge gaps: promising statistical approaches for movement analyses can connect movement patterns with specific habitat utilization but they are not yet used by entomologists. Moreover, knowing the movement patterns of many individuals and species can assist us to understand the composition and dynamics at the community level
    corecore