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Abstract

The Water Framework Directive (Directive 2000/60/EC) emphasises the need for simple tools and studies to characterise aquatic ecosystems. A wide range of methods has been developed, including different groups of biota and different taxonomic resolutions. Among these, the abundance biomass comparison (ABC) method is an important methodology widely used in marine benthic systems and well-founded from the ecological point of view. This method – with a slight modification using genera and families instead of species – was applied in a Mediterranean river (Eliche-Frío, northeast of Andalusia, Spain) using the macroinvertebrate community, together with the Margalef richness index and the Iberian BioMonitoring Working Party ( IBMWP) to determine the quality of the water. The obtained results show the suitability of the ABC curves method to analyse the macroinvertebrate community and estimate the ecological status of river ecosystems. Although both, the genus and family aggregations, showed a similar trend, the values obtained with the family level indicate a worse state of contamination than those shown with the genus level. The comparison between genus and family levels with other biological indices shows that the evaluation obtained with family aggregation is more similar to those obtained with the Margalef and IBMWP indices than the evaluation based on genera; therefore, we could conclude that this level of taxonomic resolution is adequate for the use of the ABC method in assessing the ecological status of Mediterranean rivers.
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Authors and Affiliations

Francisco Guerrero
1
ORCID: ORCID
Francisca Madrid-Vinuesa
2
Juan Diego Gilbert
1
ORCID: ORCID
Raquel Jiménez-Melero
1
ORCID: ORCID
Ana del Arco
3
ORCID: ORCID
Gema Parra
1
ORCID: ORCID

  1. Universidad de Jaén, Centro de Estudios Avanzados en Ciencias de la Tierra, Energía y Medio Ambiente, Campus de Las Lagunillas, s/n, 23071, Jaén, Spain
  2. Universidad de Jaén, Facultad de Ciencias Experimentales, Departamento de Biología Animal, Biología Vegetal y Ecología, Jaén, Spain
  3. University of Konstanz, Konstanz, Germany
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Abstract

The flow structure around rising single air bubbles in water and their characteristics, such as equivalent diameter, rising velocity and shape, was investigated using Particle Image Velocimetry (PIV) and Shadowgraphy in a transparent apparatus with a volume of 120 mL. The effect of different volumetric gas flow rates, ranging from 4 μL/min to 2 mL/min on the liquid velocity was studied. Ellipsoidal bubbleswere observedwith a rising velocity of 0.25–0.29m/s. It was found that a Kármán vortex street existed behind the rising bubbles. Furthermore, the wake region expanded with increasing volumetric gas flow rate as well as the number and size of the vortices.

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Authors and Affiliations

Björn Lewandowski
Michał Fertig
Georg Krekel
Mathias Ulbricht
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Abstract

Between December 1978 and March 1979 studies on the ichthyofauna distribution in the regions of the Scotia Sea and Antarctic Peninsula were carried out on board of the r/v "Profesor Siedlecki" during the Fourth Polish Marine Antarctic Expedition. Fisheries were carried out using bottom and pelagic trawls. The presence of about 60 species of 15 families, including among others 17 species of Nototheniidae, 9 species of Chaenichthyidae and 7 species of Bathydraconidae was recorded. Iti the waters of the west regions of the Antarctic such species as Trematomus centronotus and Austrolycichtys botriocephalus were found.

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Authors and Affiliations

Krzysztof E. Skóra
Józef Sosiński
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Abstract

The purpose of the article is to present perspectives for the development of offshore wind farms in the leading, in this respect, country in the EU and in the world – Great Britain. Wind power plays a remarkable role in the process of ensuring energy security for Europe since in 2016 the produced wind energy met 10.4% of the European electricity demand while in 2017 it was already around 11.6%. The article analyses the capacity of wind farms, support systems offered by this country and the criteria related to the location of offshore wind farms. The research has been based on the analysis of legal acts, regulations, literature on the subject, information from websites. The article shows that in recent years, the production of energy at sea has been developing very rapidly, and the leading, in this matter, British offshore energy sector is character-ised by strong governmental support.

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Authors and Affiliations

Leszek Dawid
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Abstract

In order to understand commands given through voice by an operator, user or any human, a robot needs to focus on a single source, to acquire a clear speech sample and to recognize it. A two-step approach to the deconvolution of speech and sound mixtures in the time-domain is proposed. At first, we apply a deconvolution procedure, constrained in the sense, that the de-mixing matrix has fixed diagonal values without non-zero delay parameters. We derive an adaptive rule for the modification of the de-convolution matrix. Hence, the individual outputs extracted in the first step are eventually still self-convolved. This corruption we try to eliminate by a de-correlation process independently for every individual output channel.

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Authors and Affiliations

F.A. Okazaki
W. Kasprzak

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