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  • ASTRONOMY  (2)
  • Cell & Developmental Biology  (2)
  • Pisces  (2)
  • 2000-2004
  • 1990-1994  (6)
  • 1960-1964
  • 1
    Electronic Resource
    Electronic Resource
    Reproduction in an aggregating grouper, the red hind,epinephelus guttatus (1994)
    Springer
    Environmental biology of fishes 41 (1994), S. 269-286 
    Details
    ISSN: 1573-5133
    Keywords: Spawning ; Serranidae ; Pisces ; Puerto Rico ; Protogyny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined the reproductive pattern of an aggregating grouper, the red hind,Epinephelus guttatus, in Puerto Rico. Macroscopic and histological examination of gonads confirmed that, although mature, ripe ovaries are found over a three-month period, spawning activity is limited to about 2 weeks each year. Females are determinate spawners and individuals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is attained at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located towards the edge of the insular platform. Sex ratios of individuals taken by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variation most likely attributable to a combination of differential ingress and egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patterns of seven western AtlanticEpinephelus spp. suggests that aggregation-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pattern and sperm competition. The short-term, localized, nature of spawning aggregations renders species with this reproductive mode particularly vulnerable to fishing pressure at spawning sites. Aggregating species, therefore, may require special management consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197849
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Reproduction in an aggregating grouper, the red hind,epinephelus guttatus (1994)
    Springer
    Environmental biology of fishes 41 (1994), S. 269-286 
    Details
    ISSN: 1573-5133
    Keywords: Spawning ; Serranidae ; Pisces ; Puerto Rico ; Protogyny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis We examined the reproductive pattern of an aggregating grouper, the red hind,Epinephelus guttatus, in Puerto Rico. Macroscopic and histological examination of gonads confirmed that, although mature, ripe ovaries are found over a three-month period, spawning activity is limited to about 2 weeks each year. Females are determinate spawners and individuals are able to spawn more than once during the course of the annual spawning season. The red hind is protogynous and 50% maturity is attained at 215 mm fork length. In western Puerto Rico, spawning occurs in aggregations at several sites within loosely defined areas located towards the edge of the insular platform. Sex ratios of individuals taken by hook and line at one of the aggregation areas over a consecutive six-year period, suggest considerable intra- and inter-annual variation most likely attributable to a combination of differential ingress and egress by males and females during the course of an aggregation and to fluctuations in recruitment, differential mortality by sex and sex change among years. A comparative assessment of the reproductive patterns of seven western AtlanticEpinephelus spp. suggests that aggregation-spawning is associated with medium- to large-sized groupers, while smaller groupers do not aggregate. Mating systems vary among congeners in association with trends in male-female size dimorphism, sexual pattern and sperm competition. The short-term, localized, nature of spawning aggregations renders species with this reproductive mode particularly vulnerable to fishing pressure at spawning sites. Aggregating species, therefore, may require special management consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00023817
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of annexin V (CaBP33), a Ca2+-dependent phospholipid-and membrane-binding protein, in the rat nervous system and skeletal muscles and in the porcine heart (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 152 (1992), S. 587-598 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We investigated the ultrastructural localization of annexin V a Ca2+-dependent phospholipid- and membrane-binding protein in the nervous system, heart, and skeletal muscles. The results indicate that in the cerebellum the protein is restricted to glial cells, where it is found diffusely in the cytoplasm as well as associated with plasma membranes. Bergmann glial cell bodies and processes and astrocytes in the cerebellar cortex and oligodendrocytes in the cerebellar white matter displayed an intense immune reaction product. In sciatic nerves, the protein was exclusively found in Schwann cells with a subcellular localization similar to that seen in glial cells in the cerebellum. Pituicytes in the neurohypophysis were intensely immunostained, whereas axons were not. In the heart, annexin V was restricted to the sarcolemma, transverse tubules, and intercalated discs. In skeletal muscles the protein was localized to the sarcolemma and transverse tubules. No evidence for the presence of the protein in the sarcoplasm or in association with mitochondria, the sarcoplasmic reticulum, or contractile elements was obtained. The observation that plasma membranes in cells expressing annexin V have the protein associated with them is in agreement with previous data on Ca2+-dependent binding of the protein to brain and heart membranes, and on existence of both EGTA- and Triton X-100-extractable and resistant fractions of annexin V in these membranes. The present data support the hypothesis that annexin V might be involved in membrane trafficking and suggest a role for this protein in the regulation of cytoplasmic activities in glial cells. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041520319
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  • 4
    Electronic Resource
    Electronic Resource
    NIH 3T3 cells transfected with a yeast H+-ATPase have altered sensitivity to insulin, insulin growth factor-I, and platelet-derived growth factor-AA (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 159 (1994), S. 551-560 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of intracellular pH (pHin) in the regulation of cell growth in both normal and transformed cells is a topic of considerable controversy. In an effort to study this relationship NIH 3T3 cells were stably transfected with the gene for the yeast H+-ATPase, constitutively elevating their pHin. The resulting cell line, RN1a, has a transformed phenotype: The cells are serum independent for growth, clone in soft agar, and form tumors in nude mice. In the present study, we further characterize this system in order to understand how transfection with this proton pump leads to serum-independent growth, using defined media to investigate the effects of specific growth factors on the transfected and parental NIH 3T3 cells. While both cell lines show similar growth increases in response to platelet-derived growth factor (PDGF)-BB and epidermal growth factor (EGF), they respond differently to insulin, insulin-like growth factor-I (IGF-I) and PDGF-AA. RN1a cells exhibit increased growth at nanomolar concentrations of insulin but the parental cells had only a relatively minor response to insulin at 10 μM. Both cell lines showed some response to IGF-I in the nanomolar range but the response of RN1a cells was much larger. Differences in insulin and IGF-I receptor number alone could not explain these results. The two cell lines also respond differently to PDGF-AA. RN1a cells are relatively insensitive to stimulation by PDGF-AA and express fewer PDGF α receptors as shown by Northern blots and receptor-binding studies. We propose a unifying hypothesis in which the H+-ATPase activates a downstream element in the PDGF-AA signal transduction pathway that complements insulin and IGF-I signals, while leading to downregulation of the PDGF α receptor. © 1994 wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041590319
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  • 5
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    The early ultraviolet spectral evolution of Nova Cygni 1992 (1993)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: We report on the high resolution ultraviolet line profile evolution of Nova Cygni 1992 using the International Ultraviolet Explorer (IUE) satellite and the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). Our observations cover the period from discovery in 1992 February through 1993 April. The initial expansion velocity, derived from P Cyg profiles on Mg II and other resonance lines, was about 4500 km/s. All resonance transitions displayed P Cyg profiles around the time of UV maximum. We first discuss the spectral development as the initially optically thick atomic absorption curtain became optically thin. We then present the interpretation of the nebular spectral stage. The high resolution line profiles show that the shell rapidly developed nearly symmetric knots, or filaments, of emission. The optically thin transitions show an emission weighted expansion velocity of about 1800 km/s, consistent with the velocity inferred from the radio and infrared data. The emission lines display a symmetric set of filaments that appeared as soon as the line profiles became optically thin. The GHRS observations demonstrate that the filaments were located in the inner, slower moving parts of the ejecta. These probably record an initial low wave number instability imposed on the ejecta at the time of outburst. We suggest that the likely cause is a Rayleigh-Taylor instability. The emission at later stages is dominated by the filaments and, since this phenomenon is seen in virtually all novae, nebular line formation codes will have to account for the density inhomgeneities in order to adequately determine abundances for nove ejecta.
    Keywords: ASTRONOMY
    Type: The Astronomical Journal (ISSN 0004-6256); 106; 6; p. 2408-2428
    Format: text
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  • 6
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    The early spectral evolution of Nova Cassiopeiae 1993 (1994)
    In:  Other Sources
    Details
    Publication Date: 2019-08-27
    Description: In this paper we describe the evolution of Nova Cas 1993 over the first two months of its outburst. We present an ultraviolet light curve that covers the period from announcement to just after dust began forming in the ejecta (1994 Feb. 15) and International Ultraviolet Explorer (IUE) spacecraft constraints forced us to halt our observations. We have used spherical, expanding, Non-local Thermodynamic Equilibrium (NLTE) stellar atmospheres to compute synthetic spectra and have compared the results to combined ultraviolet (low-resolution 1200-3400 A and high-resolution 2400-3300 A) spectra. Our fits show that the effective temperature of the ejecta increased from approx. 8000 to about approx. 16 000 K between 1993 Dec. 12 and 1993 Dec. 26. The temperature then increased more slowly to approx. 24 000 on 1994 Jan. 28. A preliminary abundance analysis shows evidence for hydrogen depletion, as we also found for Nova V1974 Cygni; however we find a larger enhancement of carbon, nitrogen, and oxygen. We also show that the principal mechanism for mass ejection in this nova is a radiation pressure driven wind and that mechanical driving is not necessary.
    Keywords: ASTRONOMY
    Type: The Astronomical Journal (ISSN 0004-6256); 108; 3; p. 1008-1015
    Format: text
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    NASA TECHNICAL REPORTS
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