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  • Springer  (117)
  • 1970-1974  (87)
  • 1955-1959  (28)
  • 1890-1899  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    The nesting of the Pacific ridley turtle Lepidochelys olivacea on Playa Nancite, Costa Rica (1974)
    Springer
    Marine biology 24 (1974), S. 97-107 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study of the nesting of the Pacific ridley turtle Lepidochelys olivacea was undertaken in Costa Rica on Playa Nancite — one of two beaches on which the authors had, the previous year, discovered large nesting aggregations of this species. During the 3 1/2-month period of this study, approximately 288,000 turtles nested on the 1300 m-long beach. About 99% of these nested during 3 periods of mass-nesting (arribadas). The predictability of the arribadas was investigated by observing and recording environmental parameters with which they may be correlated. The mass-nesting phenomenon, aspects of nesting behavior, and the adaptive advantages of mass-nesting are discussed. During the period of study, nearly 2,000 turtles were tagged, 102 of which were subsequently recovered. Carapace lengths and widths of 251 tagged turtles were measured. The emergence of hatchlings was recorded daily and, from these data, the incubation period and an indication of egg and hatchling survival was obtained. The activities of the various predators on eggs, hatchlings, and adults are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389343
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  • 2
    Electronic Resource
    Electronic Resource
    Notes on the Nerita (Archaeogastropoda) populations of Aldabra Atoll, Indian Ocean (1971)
    Springer
    Marine biology 9 (1971), S. 290-299 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nerita undata, N. plicata, N. polita, N. albicilla and N. textilis are common intertidal gastropods on Aldabra Atoll. Each species prefers a different level on the shore and/or different degrees of exposure to wave action. Patterns of zonation, population size-frequency structure and biomass are given. N. undata exhibits 2 distinct ecophenotypes. Normal types occur on expsed to moderately sheltered shores but are replaced by ‘type B’ in extremely sheltered conditions. Differences in shell morphology and population structure are also noted. Foraging by all species was confined to hours of darkness, generally at low tide. Activity of N. polita was induced slightly on overcast days. N. undata and N. textilis are cryptically coloured and often visible during the day. N. plicata is conspicuous, but is protected by a strong shell. N. polita and N. albicilla are often brightly and variably coloured, but both are concealed during daylight. No Nerita were found infected with trematodes, suggesting that the degree of infection was extremely low. Habitats of the Aldabran Nerita are compared with 3 species on Barbados, West Indies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372823
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  • 3
    Electronic Resource
    Electronic Resource
    Cardiac and respiratory responses in the climbing perchAnabas testudineus (1973)
    Springer
    Journal of comparative physiology 84 (1973), S. 205-226 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The heart rate ofAnabas is about 40 beats/min when breathing water and air. Tachycardia occurs as the fish takes an air breath and the rate declines as the breath holding continues but water breathing stops. Bradycardia is observed during this later phase. By the time the next air breath is taken, the heart rate has dropped to 15–30 beats/min. The heart rate of a fish breathing normoxic water but prevented from surfacing is about 42/min. Bradycardia occurs in hypoxic water under similar conditions. Tachycardia is observed in active fish when breathing hypercarbic water and air. On exposure to air bradycardia is found in resting fish but tachycardia occurs during activity. In air,Anabas usually repeats a breath when the heart rate drops to 15–25 beats/min. Tachycardia occurs immediately following an air breath. Heart rate then returns over a period of 3–6 mins to the normal resting level of 30 beats/min. The gas composition of the suprabranchial chambers has been measured and its relationship with the occurrence of an air breath, tachycardia and bradycardia is described. The experimental results are discussed in relation to the anatomy of the blood supply to the respiratory organs. The possible role of respiratory gases and pH in the control of breathing and perfusion is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697607
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  • 4
    Electronic Resource
    Electronic Resource
    Annual production of two Nova Scotian populations of Nucella lapillus (L.) (1972)
    Springer
    Oecologia 8 (1972), S. 356-370 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary One population of Nucella lapillus, under conditions of food shortage, decreased in biomass with an annual production of 5.5 kcal per m2. The second population, with plenty of food, gained biomass and the annual production was 16.7 kcal per m2. Individuals grew faster, while attaining sexual maturity and terminating growth at a larger size in the second population. In both populations, energy produced as gametes exceeded the energy produced due to growth. A 2.56 cm female was estimated to produce 46.6 egg capsules (about 1 kcal) a year but the output of males was unknown and assumed to be half that of females. The sex ratio was equal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00367538
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  • 5
    Electronic Resource
    Electronic Resource
    Some observations of sea turtle nesting activity in Costa Rica (1972)
    Springer
    Marine biology 16 (1972), S. 297-309 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Low level aerial observations were used to obtain synoptic records of the distribution of sea turtle nesting activity along both coasts of Costa Rica. Pertinent environmental information was simultaneously recorded including beach characteristics, river effluents, and evidence of coastal currents. Other correlative information was obtained from detailed maps, current charts, and climatological data. On the Caribbean coast, as expected, green turtle (Chelonia mydas) nesting was concentrated on the beaches between the Tortuguero and Parismina Rivers. On the Pacific coast, two major nesting beaches for the Pacific ridley Lepidochelys olivacea were found, each having over 100 thousand turtles aggregated offshore during the peak period between September and November. Aggregations were present at least from July through December. Massed nesting occurs each year on these same beaches and the event is known as the “salida de flota” by the natives of Guanacaste Province. Numerous less important nesting beaches were also found. Nesting density did not correlate well with beach quality but, instead, appeared to be related to the proximity of the beach to offshore currents. Oceanic current systems apparently facilitate the transport of sea turtles to the general vicinity of the important nesting beaches on both coasts of Coata Rica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347753
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  • 6
    Electronic Resource
    Electronic Resource
    Respiratory properties of the blood of the thornback ray (1974)
    Springer
    Cellular and molecular life sciences 30 (1974), S. 167-168 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Résumé Quelques propriétés respiratoires du sang de la raie (Raia clavata) ont été déterminées avec des échantillons de cathéter intravasculaire. Chaque échantillon était utilisé seulement pour deux points de la courbe de dissociation −O2−, parce que les propriétés changent après une demie-heure. On a constaté un effet de Bohr (Δ log P50/Δ pH=−0.25±0.03) ainsi que celui d'Haldane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01927712
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  • 7
    Electronic Resource
    Electronic Resource
    The chromosomes of the giant scale Aspidoproctus maximus louns. (Coccoidea-Margarodidae) with special reference to asynapsis and sperm formation (1955)
    Springer
    Chromosoma 7 (1955), S. 420-438 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The chromosomes of the African scale, Aspidoproctus maximus Louns., number 5 in the male, 6 in the female; sex chromosomes are of the XO male, XX female type. 2. Male meiosis is similar to that found in the Neotropical Llaveiini, with vesiculation of prophase nuclei, broadly dispersed polar centers, and divergent chromosomal fibers. The usual sequence of co-orientation and auto-orientation in meiosis is inverted; the chromosomes are autooriented at Metaphase I, and co-oriented at Metaphase II. 3. Asynapsis of one pair of autosomes occurs in from 14% to 52% (in different individuals) of the primary spermatocytes. Regular segregation of asynaptic chromosomes is ensured by a secondary pairing during interkinesis. 4. In spermiogenesis the chromosomes, linearly aligned, move out of the nucleus into the tail filament which forms a non-flagellated sperm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00329735
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  • 8
    Electronic Resource
    Electronic Resource
    On the cytotaxonomy of phasmids (Phasmatodea) (1959)
    Springer
    Chromosoma 10 (1959), S. 268-277 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A wide diversity in chromosome complement is found in two species of phasmids of the primitive group Prisopini—Prisopus ariadne Hebard and Prisopus berosus Westwood. P. ariadne has a diploid male complement of 28, comprising 13 pairs of relatively large mediokinetic autosomes and Neo XY sex chromosomes. P. berosus, 2n ♂=49, has relatively small autosomes most of which are mediokinetic, and retains the XO—XX sex mechanism. Chromosomal polymorphism in this species is suggested by the presence of an unequal pair of autosomes and a structural differentiation in the X in one of two males studied. The relative amount of DNA per nucleus in male germ cells (Peulgen cytophotometry) shows a significant difference in total chromosomal content between the complements of the two species. These data are discussed with reference to the cytotaxonomy of phasmids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396574
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  • 9
    Electronic Resource
    Electronic Resource
    Differential polyteny and polyploidy in diaspine coccids (Homoptera: Coccoidea) (1956)
    Springer
    Chromosoma 8 (1956), S. 709-718 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. Male germ cells ofPseudaulacaspis pentagona (TARG.), an exceptional species of the coccid subfamilyDiaspinae, contain only approximately half as much DNA (measured by Feulgen cytophotometry) as do those ofChrysomphalus ficus Ash. — a typical representative of the group. 2. Reversing this relationship, the chromosomes ofP. pentagona number 16 in the female, 8 in the male — whileC. ficus has the basic complement of the subfamily, numbering 8 in the female, 4 in the male (Brown andBentsnett 1957). 3. The total mass of the chromosomes in the 2 complements is roughly proportional to the DNA values. It is concluded that 2 downward shifts in the level of chromosomal polyteny have been associated with the doubling of the chromosome number inPseudaulacaspis pentagona. 4. The cytology of the diaspines is discussed in relation to the evolutionary origin of male haploidy in coccids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01259529
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  • 10
    Electronic Resource
    Electronic Resource
    Basalts from Madeira: A petrochemical contribution to the genesis of oceanic alkali rock series (1972)
    Springer
    Contributions to mineralogy and petrology 37 (1972), S. 91-109 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Petrological and geochemical investigations have been conducted on the little studied Neogene basaltic rocks of the Madeiran Islands. The Madeiran suite of minor intrusives and lavas consists of parental, unusually soda rich, alkali olivine basalts with hawaiite, mugearite and essexite derivatives. Olivine and clinopyroxene are dominant phenocryst and cumulus nodule phases. Low pressure fractionation of the parental magma by precipitation of these minerals gave rise to the hawaiitic trend. That olivine settling precedes clinopyroxene in the fractionation process can be deduced from Ca and Ni variations in the analysed rocks and phenocryst separates. Late stage feldspar flotation in a hawaiitic derivative liquid led to extrusive mugearites and an intrusive essexite. Low K/Rb ratios in the Madeiran basalts (ave. 325) point to the influence of phlogopite rather than hornblende in the mantle melting zone. The primitive alkali olivine basalt magma is thought to have arisen by partial melting following water release from small amounts of phlogopite (no more than 1%) at mantle depths around 100 km. A deep level of magma generation is consistent with the low values of heat flow recorded in ocean basins. Many other oceanic alkali basalt provinces remote from ridge systems may have arisen in a similar way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371069
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