ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 2005-2009  (23)
  • 1995-1999  (22)
  • 1
    facet.materialart.
    Unbekannt
    In:  EPIC3Ices journal of marine science, 316, pp. 912-927
    Publikationsdatum: 2019-07-17
    Beschreibung: Flatfishes have been the subject of scientific research since the beginning of the 19th century but information on the specific habitat requirement of the adult life stages is largely anecdotal. Detailed knowledge of flatfish habitats however is a precondition for a more ecosystem orientated approach to fisheries management. Here the association between benthic habitat and the adult life stage of three flatfish species plaice (Pleuronectes platessa), sole (Solea solea) and lemon sole (Microstomus kitt) was investigated in the English Channel. Data from groundfish surveys spanning a period of 9 years was used to identify three distinct site groups: sites where a species occurred in consistently high abundances, sites of variable or low abundance and sites at which none were caught. Following the supposition of habitat selection theories such as the ideal free distribution theory these three sites groups should represent a gradient in habitat suitability from highly suitable to less suitable and unsuitable respectively. Habitat parameters and features for the three site groups and species were described and analysed. In particular sediment type and the importance of structuring epifauna for adult flatfish was investigated. Overall plaice and sole showed very similar trends for abiotic environmental parameters such as depth, temperature, salinity and tidal currents. Lemon sole was found over distinctly different habitats which may indicate a stronger niche partitioning of this species. Sediment associations differed between the three species with plaice predominantly occurring over sandy substrates with little mud and gravel content, while sole was found over a wider range of muddy to sandy substrates. Lemon sole was predominantly found over sand however containing a higher percentage of gravel than plaice. Structuring emergent epifauna was related positively to plaice and lemon sole abundances. These structures might be important as they tend to harbour larger numbers of epibenthic species upon which adult plaice and lemon sole prey. No such trend was found for the tactile feeding sole which mainly forages on infaunal polychaetes and molluscs.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    facet.materialart.
    Unbekannt
    In:  EPIC3Benthic habitats and the effects of fishing,265276,American Fisheries Society Symposium 41,Bethesda, Maryland, ISBN: 1-888569-60-3
    Publikationsdatum: 2019-07-17
    Beschreibung: Fishers have often complained that standard United Kingdom groundfish survey data do notadequately reflect the grounds targeted by commercial fishers, and hence, scientists tend to make overcautiousestimates of fish abundance. Such criticisms are of particular importance if we are to make acreditable attempt to classify potential essential fish habitat (EFH) using existing data from groundfishsurveys. Nevertheless, these data sets provide a powerful tool to examine temporal abundance of fishon a large spatial scale. Here, we report a questionnaire-type survey of fishers (20012002) that invitedthem to plot the location of grounds of key importance in the Irish Sea and to comment on key habitatfeatures that might constitute EFH for Atlantic cod Gadus morhua, haddock Melanogrammus aeglefinus,and European whiting Merlangius merlangus. Plotted grounds were cross-checked using records ofvessel sightings by fishery protection aircraft (19851999). A comparison of the areas of seabedhighlighted by fishers and the observations made on groundfish surveys were broadly compatible forall three species of gadoids examined. Both methods indicated important grounds for cod and Europeanwhiting off northern Wales, the Ribble estuary, Solway Firth, north of Dublin, and Belfast Lough. Themajority of vessel sightings by aircraft did not match the areas plotted by fishers. However, fishingrestrictions, adverse weather conditions, and seasonal variation of fish stocks may have forced fishersto operate outside their favored areas on the (few) occasions that they had been recorded by aircraft.Fishers provided biological observations that were consistent among several independent sources (e.g.,the occurrence of haddock over brittle star [ophiuroid] beds). We conclude that fishers knowledge isa useful supplement to existing data sets that can better focus more detailed EFH studies.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Inbook , peerRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 217-222 (May 1996), p. 1759-1764 
    ISSN: 1662-9752
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 35 (1999), S. 527-535 
    ISSN: 1432-0983
    Schlagwort(e): Key wordsCenococcum geophilum ; Internal transcribed spacer (ITS) ; Ribosomal DNA (rDNA) ; Group-I intron ; Mycorrhizae ; RNA secondary structure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cenococcum geophilum is an ecologically important mycorrhizal fungus with a global distribution and a wide host range. It has been difficult to study since it forms only sterile mycelia and, occasionally, sclerotial bodies. Because of its lack of morphological variability, its taxonomy and phylogenetic origins have until recently remained unclear. To better understand the genetic variation and environmental adaptability of C. geophilum, a molecular phylogeny was constructed based on the nuclear ribosomal DNA internal transcribed spacers (ITS1 and ITS2) of 69 isolates from various hosts and habitats. The results suggest DNA sequence conservation in the ITS regions. Considering its broad geographic and host range, this ITS conservation was unexpected. Our data imply that the ITS2 region is under evolutionary pressure to maintain the RNA secondary structure (similar to the pressure on the CgSSU introns) involved in the post-transcriptional processing of rRNA. Also, C. geophilum has very short ITS regions, thus limiting the number of mutable sites. This limited ITS variability suggests a recent radiation of C. geophilum, having been geographically distributed by a variety of efficient processes. C. geophilum appears to be a single taxonomic entity, possibly a single species. Therefore, it is an extremely adaptable, as well as ecologically valuable, taxon.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 29 (1996), S. 377-387 
    ISSN: 1432-0983
    Schlagwort(e): Key words Self-splicing ; Group-I intron ; Ribosomal RNA ; Cenococcum geophilum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  A family of optional group-I introns was found near the 3′ end of the nuclear small subunit rRNA genes in 61 out of 70 isolates of the deuteromycete mycorrhizal fungus Cenococcum geophilum. DNA sequence polymorphisms among the introns (termed CgSSU introns) from ten of the isolates were studied. The sequences, ranging in size from 488 to 514 nucleotides, were from 93.2% to 99.6% similar to each other. Mutations were less common in predicted base-paired regions (33% of all mutations) than in free-standing regions (67%). The introns were self-spliced in vitro and were closest to subgroup IC1 according to sequence and predicted secondary structure. Group-I intron pairing regions P1 through P10, including core regions P, Q, R and S, were present in all ten CgSSU introns studied. No lengthy open reading frames were found in any of the introns, indicating that the introns do not encode a protein, and therefore may not be mobile. It is likely that a single intron entered a progenote of C. geophilum and changed as the species evolved.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Pattern analysis and applications 2 (1999), S. 251-263 
    ISSN: 1433-755X
    Schlagwort(e): Key words: Computer vision; Object recognition; Saccadic behaviour
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract: The automated recognition of targets in complex backgrounds is a difficult problem, yet humans perform such tasks with ease. We therefore propose a recognition model based on behavioural and physiological aspects of the human visual system. Emulating saccadic behaviour, an object is first memorised as a sequence of fixations. At each fixation an artificial visual field is constructed using a multi-resolution/ orientation Gabor filterbank, edge features are extracted, and a new saccadic location is automatically selected. When a new image is scanned and a ‘familiar’ field of view encountered, the memorised saccadic sequence is executed over the new image. If the expected visual field is found around each fixation point, the memorised object is recognised. Results are presented from trials in which individual objects were first memorised and then searched for in collages of similar objects acting as distractors. In the different collages, entries of the memorised objects were subjected to various combinations of rotation, translation and noise corruption. The model successfully detected the memorised object in over 93% of the ‘object present’ trials, and correctly rejected collages in over 98% of the trials in which the object was not present in the collage. These results are compared with those obtained using a correlation-based recogniser, and the behavioural model is found to provide superior performance.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 17 (1998), S. 656-660 
    ISSN: 1432-203X
    Schlagwort(e): Key wordsJuncus accuminatus ; Callus regeneration ; Medium pH ; Phytoremediation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A reliable callus regeneration and shoot multiplication system for wetland monocot Juncus accuminatus has been established. Callus was induced from 6-day-old seedlings on Murashige and Skoog medium supplemented with 5 mg/l picloram. The callus differentiated into shoots upon transfer to 5 mg/l benzyladenine (BA)-supplemented medium. Effects of medium pH (3.8–7.8) and source of callus (grown in the dark or continuous light) on regeneration were determined. Both parameters significantly influenced regeneration. Regenerated shoots were multiplied by subculturing shoots onto 5 mg/l BA medium at 4-week intervals. The regenerated shoots were rooted on 0.1 mg/l naphthaleneacetic-acid-supplemented medium. The rooted plants were transferred to pots containing a commercial potting mix and established in the greenhouse. Plants covered with plastic grew faster and flowered earlier than uncovered plants. All plants set viable seeds.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell reports 18 (1998), S. 71-75 
    ISSN: 1432-203X
    Schlagwort(e): Key wordsTypha latifolia ; Cattail ; Remediation ; Shoot regeneration ; Wetland monocot
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A regeneration system for broadleaf cattail (Typha latifolia), a common freshwater wetland monocot, was established. Callus was induced from 3 day-old seedlings on Murashige and Skoog medium supplemented with picloram or 2,4-dichlorophenoxyacetic acid (2,4-D). Picloram induced more callus growth than 2,4-D. Callus proliferated predominantly from the root-shoot junction and sporadically from the roots. Upon transfer to N6-benzyladenine-supplemented medium, callus regenerated shoots. The mode of regeneration was organogenesis, with shoots arising from organized areas of callus. The regenerated shoots rooted in vitro and, on transfer to pots containing a commercial potting mix, were established in a greenhouse. The plants grew vigorously and produced a high root mass. No albinos and no morphological aberrations were observed in the regenerates.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Publikationsdatum: 2007-10-08
    Beschreibung: The Valhall Field is an Upper Cretaceous chalk reservoir located in the Central Graben area of the North Sea with production coming from the fractured Tor and Hod formations. Well tests and production history indicate that these formations are highly heterogeneous and that significant fluid flow occurs through both the matrix and fracture system. However there remained significant uncertainty about the specific controls and location of the main productivity conduits and how they would influence sweep efficiency during planned water flood. To address these uncertainties a range of possible conceptual fracture models were considered with respect to controls on major flow within the reservoir. Analysis indicated that the reservoir is dominated by a connected series of seismic scale faults acting as major flow conduits with smaller fractures providing a less significant enhancement to matrix permeability. A key input to this study was the examination of over 80 well tests. Simulation of a number of key well tests using a simple discrete fracture network model comprising a connected fault network and pseudo-matrix layer was able to reproduce the majority of the observed pressure derivative shapes. This gave some confidence to the understanding of major reservoir flow paths as well as providing calibrated fault properties for direct inclusion within the simulation model.
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Publikationsdatum: 2007-10-08
    Beschreibung: Different conceptualizations of fracture networks have been generated in order to simulate well tests in fractured reservoirs. These models have two purposes: firstly to investigate whether the behaviour of realistic fracture networks can be emulated with more simple models; and secondly to assess whether different sources of anisotropy have characteristic and recognizable influences on the pressure derivative. The anisotropy of the fracture networks was increased by decreasing the angle between two originally orthogonal fracture sets, and by increasing the permeability contrast between two orthogonal fracture sets. Results indicate that simple models can capture the first-order behaviour of more realistic examples. However because early time data are strongly influenced by the connectivity of the fracture network, the degree of anisotropy can only be assessed at later times in a test. Increasing anisotropy results in increasing heterogeneity and compartmentalization, and permeability anisotropy in an orthogonal system can only partially replicate the behaviour of a geometrically anisotropic system.
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...