Comb mode filtering silver mirror cavity for spectroscopic distance measurement.

In this work we present a design of an external optical cavity based on Fabry-Perot etalons applied to a 100 MHz Er-doped fiber optical frequency comb working at 1560 nm to increase its repetition frequency. A Fabry-Perot cavity is constructed based on a transportable cage system with two silver mirrors in plano-concave geometry including the mode-matching lenses, fiber coupled collimation package and detection unit. The system enables full 3D angle mirror tilting and x-y off axis movement as well as distance between the mirrors. We demonstrate the increase of repetition frequency by direct measurement of the beat frequency and spectrally by using the virtually imaged phased array images.

Internet-based system for anti-tumor chemotherapy evaluation.

The Internet-based system DIOS addresses the issues of anti-tumor chemotherapy and its evaluation. The repository of chemotherapeutic regimens (CHRs) stored in XML structured format constitutes the core of the system. Several applications have been created based on this repository, in order to allow users to browse current CHRs and procedures of planning and evaluation of chemotherapy based on the dose intensity concept. This freely available system uses technology based on the XML standard and XSLT transformations.

Web portal for management of bioindication methods and ecotoxicological tests in ecological risk assessment.

The objective of this article is to inform about efforts to design and implement a data model that can parametrically describe and store information about a wide range of ecotoxicological tests and bioindication methods used in Ecological Risk Assessment (EcoRA). At the same time it describes comprehensive web-based portal built on this model that can be used to quickly find relevant biological assays (ecotoxicological biotests) for given situation and therefore support the decision-making process in EcoRA. The model structure, features of the corresponding website and its current content is described in detail and proposed development and possible collaboration is outlined. The portal (DATEST) is located at http://projects.cba.muni.cz/datest. The aim of this work is to complement existing EcoRA decision-support tools with a web-based engine for storing and searching biological tests and methods used in EcoRA as there is currently no similar informational source available on the Internet.

Bioaccumulation of mercury in muscle tissue of fish in the Elbe River (Czech Republic): multispecies monitoring study 1991-1996.

The study monitored mercury (Hg) contamination of fish muscle tissue at 13 geographical sites that can be regarded as crucial points for an ecotoxicological assessment of the Czech Republic section of the Elbe River. The descriptive part of the study was primarily aimed at comparative evaluation of the Hg load during the period 1991-1996. The conclusions were supported by multivariate statistical analyses of the content of Hg in the muscle tissue of 1251 fish belonging to 23 species with four dominant indicator species: Perca fluviatilis (n=163), Abramis brama (n=173), Rutilus rutilus (n=148), and Leuciscus cephalus (n=166). Considering data from 3- to 5-year-old fish, significantly increased contamination was detected in typical predators compared to the other fish species in all sites (P<0.001). On the other hand, omnivorous and planctivorous species were ranked as the least sensitive for Hg pollution. Perch appeared to be the most contaminated species in the sample with muscle Hg concentration in the range of 0.840-1.398 mg Hg kg(-1). Although less contaminated than perch, muscle contamination of bream sensitively separated differently contaminated sites; the highest load ranged from 0.368 to 0.543 mg Hg kg(-1). Time-related comparison of sampling campaigns revealed no significant trend changes, in either sediment samples or fish tissue. Thus, the analyses documented an evidently rather stabilized total Hg pollution in the Elbe River environment. Multivariate multispecies analyses found the age of analyzed individuals and the feeding strategy of a given species as the most important, however mutually interactive, covariates for Hg accumulation in muscle tissue. The analyses revealed decreasing sensitivity of older predator individuals to differentiate highly and moderately contaminated sites. Benthophagous species mostly kept their discrimination capacity toward contaminated sites in all age categories, with the exception of bream that was rather linked to the pattern typical for predator species. The unclear position of omnivorous species, represented namely by roach, corresponded with their weak bioindicator power, mainly in the young age categories.

Bioaccumulation of mercury in various fish species from Orlík and Kamýk water reservoirs in the Czech Republic.

The study evaluated contamination of fish by mercury in two important Czech water reservoirs, Orlík and Kamýk, which receive water from the whole watershed of Otava and Vltava rivers. Contamination of these reservoirs reflects the situation in southern and western Bohemia. Six environmentally representative sites were sampled in the area of interest and the evaluation was based on regression models relating Hg concentrations in fish tissues to the age of fish. A total number of 170 analyzed individuals from 3 indicative species (Rutilus rutilus, Abramis brama, and Perca fluviatilis) allowed site-specific analyses of model residuals. The results of biological monitoring corresponded to the sediment analyses and suggested that Orlík reservoir receives a substantial part of the pollution from the Vltava river. Temporary oxygen deficiency and decreased value of pH were probably the key factors responsible for the increased exposure of fish to Hg in the Kamýk reservoir. An additional comparison of 286 analyzed individuals belonging to 11 fish species provided the following decreasing order for muscle contamination: typical predators