Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (2)
  • 1980-1984  (1)
  • 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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    MRI of ischemic lesions in gerbil brain (1994)
    Springer
    Magnetic resonance materials in physics, biology and medicine 2 (1994), S. 365-366 
    Details
    ISSN: 1352-8661
    Keywords: global forebrain ischemia ; MRI ; histology ; gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics
    Notes: Abstract Brain temperature was varied during global forebrain ischemia in adult male Mongolian gerbils to produce a graded response to the ischemic insult. The severity of damage in the dorsal hippocampus was then quantified 4 days after the event withT 2-weighted 2DFT images and with histology. Statistically significant correlation was observed between magnetic resonance imaging (MRI) score and brain temperature and between MRI score and the area of the CA region in the dorsal hippocampus measured by histology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01705273
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Diel changes in plankton and water chemistry in Wicken brickpit (1980)
    Springer
    Hydrobiologia 74 (1980), S. 249-271 
    Details
    ISSN: 1573-5117
    Keywords: plankton ; diet change ; vertical migration ; crowding ; light intensity ; pond ; water chemistry ; nutrient changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a flooded Fenland brickpit 3 metres deep a 24-hr study (supplemented by other observations in the field and in the laboratory) revealed marked changes with depth and time in oxygen concentration, pH, total carbon dioxide, ammonium, oxidised nitrogen, phosphate and silica; as well as changes in the rate of cell-division and the vertical distribution of phytoplankton (Dinobryon and Peridinium), and the feeding and vertical movement of zooplankton (copepods, Bosmina, Ceriodaphnia, Polyarthra and Keratella). Directional trapping of zooplankton revealed relationships between population density and the intensity of locomotory activity (a relationship subsequently supported by laboratory experiments), and between the rate of change of light intensity and the direction of swimming. Significant temporal segregation of the occupancy of a given level by zooplankters implies interspecific competition. Transient peaks in the concentrations of some nutrients near the surface are tentatively attributed to nutrient release by zooplankters that have fed at depth. Small-scale temporal and spatial heterogeneity of the type described here may help to explain the ‘paradox of the plankton’. These marked diel changes in water chemistry suggest that conclusions based on the analysis of single water samples should be viewed with caution.[/p]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008758
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...