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  • 1990-1994  (3)
  • 1980-1984  (4)
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  • 1
    Electronic Resource
    Electronic Resource
    Chela loss in the shore crab Carcinus maenas (Crustacea: Brachyura) and its effect on mating success (1994)
    Springer
    Marine biology 121 (1994), S. 247-252 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Field and experimental studies were conducted to determine the incidence of chela loss and its effect on mating success in a population of the shore crab Carcinus maenas (Linnaeus, 1758) inhabiting the Menai Straits, North Wales. The study was performed between 1989 and 1993. Male crabs showed a higher degree of chela loss (12.5%) than females (7.9%). In males, frequencies ranged from ∼10% at sizes 50 mm CW (carapace width) up to ∼30% in the largest crabs of 70 to 80 mm CW. The percentage of females with missing chelae appears to be unrelated to size. The most common type of chela loss in the population studied was of a missing crusher chela of right-handed crabs. Red crabs, which are assumed to be in prolonged intermoult, had a much higher degree of chela loss (20.5%) than the green, early intermoult crabs (9.7%). The proportion of red crabs with chela losses increased with size, possibly reflecting an increase in intermoult duration with size. In green crabs, there was no such increase. The proportion of male crabs with missing chelae found in mating pairs in the field was much lower than that found in the adult unpaired population, suggesting that the loss of a chela constitutes a handicap to a male crab when trying to mate. Also, by studying the relative frequencies of different categories of chela loss, it is suggested that the loss of a crusher chela exerts a more deleterious effect than the loss of a cutter. Experiments were performed in the laboratory where pairs in pre-copula were confronted with an additional single male in various combinations of sizes and patten of chela loss. These showed that the loss of a chela constitutes a handicap for a male crab when either competing for or defending a paired pre-moult female. This handicap was estimated to be equivalent to a reduction in size of 7 to 8 mm CW relative to the size of the competitor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00346732
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Biological and physical aspects of migration in the estuarine amphipod Gammarus zaddachi (1992)
    Springer
    Marine biology 112 (1992), S. 437-443 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The amphipod Gammarus zaddachi (Sexton) conducts extensive migrations along estuaries from near the limit of tidal influence in winter to more downstream reaches (where reproduction occurs) in spring. A return migration then takes place, primarily by juveniles, until the seaward areas are depopulated in winter. The present study was conducted between 1988 and 1990 in the Conwy Estuary, North Wales. This represents the first investigation on this species in a strongly tidal estuary, where the amphipods appear to migrate vertically into the water column on flood or ebb tides to control horizontal transport and to maintain preferred distributions. The timing of vertical migration seems to be largely controlled by an endogenous circatidal swimming rhythm. Phasing of peak activity relative to the time of expected high tide varies with season; upstream migrants in the autumn showed peak activity at the time of expected high tide, while in the spring at the time of downstream migration the rhythm was phase-delayed, with peak activity during the expected ebb tide. Together with the season, position along the estuary also affected the timing of peak endogenous activity; downstream migrants, originally active on the ebb tide and experimentally displaced seawards, showed a phase-advance of the rhythm relative to the time of high tide. Salinity-preference behaviour also varied between different developmental stages, with ovigerous females (downstream migrants) showing no preference between fresh and saline water, and juveniles (upstream migrants) showing a significant preference for freshwater. The interactions of endogenous rhythmicity and salinity-preference behaviour are discussed as controlling factors of migration in this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00356289
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    After Waterman (1983)
    [s.l.] : Nature Publishing Group
    Nature 304 (1983), S. 193-194 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A LITTLE over 20 years ago The Physiology of Crustacea, edited by T. H. Waterman, was published by Academic Press. It was a two-volume work which synthesized and stimulated the study of crustacean biology in a manner which has been of fundamental importance for the development of the subject. Now, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/304193b0
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Vertical swimming in wave-induced currents as a control mechanism of intertidal migration by a sand-beach isopod (1991)
    Springer
    Marine biology 111 (1991), S. 49-54 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both the vertical and horizontal distributions ofEurydice pulchra (Leach) within the water column of the surf zone were recorded throughout complete tidal cycles on a sandy beach in North Wales during the summer of 1989. Upon emerging from the sand, the isopods tended to swim up in the water column, where transport onshore would be facilitated by the wave-induced, onshore currents which laboratory wave-tank experiments have confirmed to occur near the water surface. This combination of active and passive transport to the water's edge results in high numbers of individuals in the narrow swash zone. At and just after the time of high tide, individuals swim to the water/sediment interface where, as again confirmed by wave-tank experiments, the predominant water movement is offshore. Continued swimming near the bottom during the ebb tide before reburrowing in the sand ensures transport downshore and avoidance of stranding above the characteristic level of zonation on the shore. Vertical migrations ofE. pulchra in the water column permit differential exploitation of up and downshore currents to achieve horizontal migration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01986345
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Urinary pyrimidine excretion in arginase deficiency (1981)
    Springer
    Journal of inherited metabolic disease 4 (1981), S. 207-210 
    Details
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A high-performance liquid-chromatographic method was used to separate and identify uracil, uridine, pseudouridine and orotic acid after preliminary extraction in two patients (McKusick 20780). Urinary uracil excretion was 10–35 times normal in both patients with arginase deficiency. Uridine and orotic acid, not normally detected, were excreted in large amounts and were directly influenced by protein intake. Their excretions were correlated with urinary arginine excretion. Urinary uracil levels remained consistently high and showed minimal variations with increased protein intake or urinary arginine levels. The measurement of urinary pyrimidines appears to be useful for the detection, differential diagnosis and dietary monitoring of patients with urea cycle disorders. The data presented extends this observation to include patients with arginase deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02263653
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Treatment of hyperargininaemia due to arginase deficiency with a chemically defined diet (1982)
    Springer
    Journal of inherited metabolic disease 5 (1982), S. 95-99 
    Details
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A brother and sister aged 11 and 17 years have been reported previously to have hyperargininaemia and arginase deficiency: they were treated with a semi-synthetic diet consisting of fat, carbohydrate, minerals, vitamins and essential amino acids in amounts equivalent to 0.55–0.65 g protein kg−1 day−1 for 2 years. Plasma arginine levels fell from 0.50–0.90 µmol/l to 0.13–0.30 µmol/l (normal range 0.02–0.15). Increased concentrations of arginine in the cerebrospinal fluid (CSF) fell from 0.069–0.098 µmol/l to 0.040–0.056 µmol/l (normal mean ± SD=0.020±0.006). Dibasic aminoaciduria returned to normal within 1 week. Substitution of the keto-acid analogues of five essential amino acids in the formula lowered arginine concentrations further, but proved to be unpalatable. Urinary concentrations of orotic acid, uridine and uracil fell toward normal but remained increased, even when the plasma ammonia concentration was measured as normal. Both patients showed a stable clinical improvement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01800000
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Intermittent non-ketotic dicarboxylic aciduria in two siblings with hypoglycaemia: An apparent defect in β-oxidation of fatty acids (1980)
    Springer
    Journal of inherited metabolic disease 3 (1980), S. 19-24 
    Details
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two siblings with intermittent hypoglycaemia, lethargy and coma associated with fatty infiltration of the liver are reported. Urine contained C6 to C14-dicarboxylic acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02312518
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    Paper (German National Licenses)
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