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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 131 (1998), S. 479-487 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reproductive and larval biology of the common Antarctic cushion-star Odontaster validus Koehler (Echinodermata: Asteroidea) were studied in a shallow-water population at Signy Island in the maritime Antarctic. The gonad index peaked in April/May, and injection with 1-methyladenine indicated that competence to spawn peaked in May/June. Gastrulae were first detected in May, and maximal water-column larval densities were measured in July. Reproduction was therefore highly seasonal, although not all individuals appeared to spawn each year. The pyloric caeca index increased in summer (typically November to March, but variable between years) and decreased during winter (June to October), suggesting that feeding activity was seasonal. All aspects of biology investigated showed significant interannual variability. Comparison with previous studies in the high Antarctic at McMurdo Sound indicated a similar if more pronounced seasonality at Signy, but the warmer seawater temperatures in the maritime Antarctic (particularly in late winter/early spring from September onwards) resulted in faster larval development at Signy.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An allozyme survey, using starch-gel electrophoresis, was carried out on eight populations of the Antarctic nemertean worm Parborlasia corrugatus (McIntosh, 1876) collected from locations around the South Orkney Islands, Antarctica. These populations were separated by distances in the order of tens of kilometres. Genetic variation was estimated over 22 enzyme loci for all populations examined, giving an observed heterozygosity of 0.142. This was much lower than the expected heterozygosity (H e  = 0.201), and it was found that there was a significant deficiency of het‐erozygotes across four enzyme loci ( p ≤ 0.01). A more detailed examination of this deficiency of heterozygotes was undertaken for the six populations and six variable enzyme loci for which the most complete data sets existed. A significant deficiency of heterozygotes was found at the enzyme locus Odh-1 for four of the six populations examined ( p ≤ 0.01). Mean F is (0.240) indicated a significant ( p ≤ 0.01) within-population component of the heterozygote deficiency estimated for the six populations sampled, and this was mainly due to the␣Ap-1, Odh-1 and Pgm-1 loci. The mean F st value (0.036) was also significant ( p ≤ 0.01), indicating a degree of genetic differentiation between populations. The observed levels of genetic differentiation between populations of P. corrugatus and the significant heterozygote deficiencies were unexpected, because this species has been reported to have a long-lived planktotrophic larva. It is hypothesised that recruitment of P. corrugatus in the South Orkney Islands originates from genetically distinct populations located in the Weddell Sea and to the west of the Antarctic Peninsula. Shifts in the relative position of the Weddell Sea Front, Weddell–Scotia Confluence and Scotia Front, relative to the South Orkney Islands, provide a mechanism for variation in the origin of recruits over time.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 131 (1998), S. 647-658 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The seasonality of polypide cycling has been investigated for three species of erect bryozoans from Antarctica: Isoseculiflustra rubefacta (Kluge, 1914), Nematoflustra flagellata (Waters, 1904) and Himantozoum antarcticum (Calvet, 1905). Approximately ten colonies of each species were collected monthly by SCUBA divers over a 14 mo period during 1992/1993, and the status of each individual zooid was classified as differentiating/regenerating, active (feeding autozooids), degenerate (brown body) or sexually reproductive (ovicells present, or zooid containing a larva). Polypide cycling in all three species was distinctly seasonal. New zooids formed at the growth margin and typically contained actively feeding polypides for ≃9 mo before these polypides degenerated into brown bodies in the austral winter (June). Very few polypides were active in the period from June to August, when water-column food levels were at their lowest; after this period new polypides differentiated. Individual zooids typically underwent a total of five (I. rubefacta and N. flagellata), or at least four (H. antarcticum) complete polypide cycles before becoming senescent. Polypide lifetimes generally became shorter as the age of the zooid increased. Sexual reproduction was also distinctly seasonal in these species, with bands of ovicells or sexually reproductive zooids being formed each year in late summer once a given colony had grown to a threshold size (or age). Larvae were then brooded for ≃10 mo before being released in January/February (N. flagellata) or February/March (H. antarcticum). The seasonal patterns of polypide cycling are related clearly to the variations in food availability, and these species appear to have the longest zooid lifetime (≃5 yr) and the slowest polypide cycling (once per year with polypide lifetimes up to 10 mo) reported for any bryozoan so far.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 121 (1998), S. 457-464 
    ISSN: 1432-1106
    Keywords: Key words Otolith-ocular response ; Utricle ; Unilateral function ; Eccentric rotation ; Video-oculography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A modified rotatory chair test is reported in which radial acceleration, generated by eccentric displacement of the subject during constant angular velocity, is exploited as a unilateral stimulation to the otolith organs. During constant angular rate rotation, the test subject is displaced laterally on the rotating turntable by 3.5 cm, so that one labyrinth becomes aligned with the rotatory axis while the second – eccentric – labyrinth is solely exposed to the altered gravito-inertial acceleration (GIA). Previously reported results showed that the direction of the response is independent of the direction of turntable rotation, ruling out any canal influence, and indicated that in a normal population the response, measured in one eye, was symmetrical for displacement of the left and right labyrinths. This mode of stimulus thus appears to elicit a unilateral otolith-ocular response (OOR). Examination of this unilateral OOR was extended in the present study; comparative testing with head-tilt to gravity, i.e. involving bilateral stimulation to the otolith organs, was carried out. Movements of both eyes were recorded (by three-dimensional video-oculography), in order to examine response conjugacy. To verify the specificity of the unilateral stimulus, tests were performed with patients who had previously undergone unilateral section of the vestibular nerve as treatment for acoustic neuroma. The eccentric displacement profile (EDP) and head-tilt stimulus each included ten cycles of left-right oscillation in order to permit signal averaging. In the normal subjects (n=12) the torsional component of the OOR proved to be both labyrinth-symmetrical and conjugate, during both bilateral and unilateral otolith stimulation. OOR gain (ocular torsion/GIA tilt) was higher for bilateral than unilateral stimulation. Bilateral OORs, obtained from three of the five unilaterally deafferented patients, proved less symmetrical and conjugate than in the normals. Unilateral OORs in all five patients were characteristically asymmetrical, with little or no response during stimulation of the diseased labyrinth.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1076
    Keywords: Key wordsEnterococcus faecium ; Vancomycin resistance ; Colonisation ; Infection control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to determine the extent of vancomycin resistant enterococcus (VRE) colonisation within a paediatric oncology unit, the risk factors for the acquisition of the organism, the molecular epidemiology of the isolates and the impact of infection control measures, extensive patient and environmental surveillance was undertaken with identification, antibiotic susceptibility testing and pulsed-field gel electrophoresis (PFGE) of all VRE isolates. A matched case control study was carried out. Fourteen patients (19% of screened patients) with VRE colonisation were identified (12 with Enterococcus faecium). All isolates manifested the Van A phenotype. Extensive environmental contamination with VRE was present. PFGE of E. faecium isolates from 10 patients and from five of six environmental cultures revealed patterns suggesting genetic relatedness. Following comparison of the 14 cases with 41 controls matched for age (±4 years) and cohabitation on the oncology unit, risk factors for colonisation with VRE included duration of neutropenia, (OR, 3.72; 95% CI, 1.0–13.1), and antibiotic therapy, (OR, 4.07; 95% CI, 1.08–15.3), the number of antibiotic agents received, (OR, 8.4; 95% CI, 1.34–34.3) and the duration of therapy with amikacin, (OR, 10.7; 95% CI, 1.4–81.5), ceftazidime, (OR, 11.5; 95% CI, 2.2–59.9) or teicoplanin, (OR, 12.3; 95% CI, 2.25–67.4). Implementation of stringent infection control measures reduced environmental contamination from 25% of samples in week 1 to none in week 11. Two additional colonised patients were identified during the subsequent 6 months. Conclusion Risk factors for VRE colonization in paediatric oncology patients included duration of neutropenia, duration of any antibiotic therapy, exposure to ceftazidime, amikacin or teicoplanin and the number of antibiotics used. The study suggests that environmental contamination played an important role in patient-to-patient transmission of VRE and interventions including implementation of infection control measures were associated with a decreased incidence of gastro-intestinal colonisation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 794 (1996), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The burden of ozone-depleting chemicals in the lower atmosphere has been decreasing since 1994 as a result of the Montreal Protocol. Here we show how individual chemicals have influenced this decline, in order to estimate how the burden could change in the near future. Our measurements of ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food quality 21 (1998), S. 0 
    ISSN: 1745-4557
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Texture profile analysis (TPA) and shear force of restructured beef products with one of five binders (isolated soy protein, sodium caseinate, waxy modified corn starch, carrageenan, and oat flour) were analyzed at 35, 45, 55 and 65 C. Hardness, cohesiveness, springiness, gumminess, and chewiness were significantly affected (p〈0.05) by binders, temperatures and their interactions. Hardness and gumminess showed no significant (p〈0.05) differences among binders and temperatures below 45C, but each increased between 45 – 65C. Isolated soy protein gave the highest hardness and gumminess values; oat flour, the lowest at 55 and 65C. Except for oat flour, cohesiveness, springiness and chewiness decreased from the raw state until 45C, and then increased. Oat flour gave the highest values for cohesiveness, springiness and chewiness 〈 45C; the lowest at 55 and 65C. Oat flour gave the lowest shear force (N) values at 55 and 65C. Conclusions were reached that the influence of these binders on the textural parameters of restructured beef products was temperature-dependent.
    Type of Medium: Electronic Resource
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  • 9
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    London : Periodicals Archive Online (PAO)
    Journal of theological studies. n.s.:46 (1995) 818 
    ISSN: 0022-5185
    Topics: Theology and Religious Studies
    Notes: AUTHORS AND BOOKS REVIEWED OR NOTICED
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  • 10
    ISSN: 1573-4897
    Keywords: power spectral density ; 3D fibre waviness ; confocal laser scanning microscopy ; high spatial resolution ; characterisation ; glass fibre reinforced ; polymer composites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A pilot study has been completed into the accurate measurement of 3D fibre waviness in high packing fraction, unidirectional, glass fibre reinforced polymer epoxy. It has been shown that the confocal laser scanning microscope (CLSM) can determine fibre waviness amplitudes,A⩽40 µm andsimultaneously fibre wavelengths, λ⩽4 mm. Knowing the fibre-centre coordinates in 3D with sub-micron precision, the fibre waviness may be characterised in terms of the power spectral densitiesS u andS w orthogonal to the fibre direction (taken to be in they direction) and also in terms of the power spectral densities of fibre slopes,S u′ andS w′. In future studies, these characterisation parameters will enable models linking random fibre waviness to compressive strength to be evaluated.
    Type of Medium: Electronic Resource
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