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  • 1
    Electronic Resource
    Electronic Resource
    DNA fingerprints of a gorgonian coral: a method for detecting clonal structure in a vegetative species (1992)
    Springer
    Marine biology 114 (1992), S. 317-325 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Clonal reproduction, a common life history strategy among sessile marine invertebrates, can lead to high local abundances of one to a few genotypes in a population. Analysis of the clonal structure of such populations can provide insight into the ecological and evolutionary history of the population, but requires markers that can identify individual genets. Forensic and demographic studies have demonstrated that DNA fingerprinting can provide markers that are unique for an individual genotype. We have generated DNA fingerprints for over 70 colonies of the clonal gorgonian, Plexaura A (Plexaura sp. A) collected from June 1990 through July 1991 in the San Blas Islands, Panama. DNA fingerprints within a singic individual were identical and fingerprinting resolved multiple genotypes within and among reefs. On one reef in the San Blas Islands, Panama, 59% of the colonies sampled were of one genotype and this genotype was not found on any other sampled reefs. A previous study using tissue grafts identified 13 putative clones on these reefs, while DNA fingerprints of the same colonies differentiated 17 genotypes. The present study demonstrates the utility of DNA fingerprinting for distinguishing clones and for identifying clonal structure of marine invertebrate populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349534
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  • 2
    Electronic Resource
    Electronic Resource
    Reproductive success in the Caribbean octocoral Briareum asbestinum (1992)
    Springer
    Marine biology 114 (1992), S. 157-163 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For most sessile marine invertebrates the number of offspring produced by an individual is often determined indirectly from counts of eggs present, with the assumption that all or most become viable offspring. Few field data on the actual number of offspring produced per individual (reproductive success) have been reported. We examined reproductive success in the octocoral, Briareum asbestinum (Pallas), by measuring embryo densities on 40 female colonies on two reefs (Pinnacles and House reefs) in the San Blas Islands, Panama from 1986 to 1988. The percentage of female colonies with mature eggs which subsequently released embryos was low, ranging from 46.6% in 1986 to 5.0% in 1988. Reproductive success was significantly different between reefs. Pinnacles reef had significantly more successful colonies (those releasing embryos) than House reef in all three years and significantly higher embryo densities in 1986 and 1987. There was a significant positive correlation between female reproductive success and the density and proximity of nearby males in both 1986 and 1987. In addition, fertile female branches placed 25 cm away from male branches produced significantly more embryos than female branches placed 50 cm away. In 1988 two groups of female branches were placed at distances of 〈50 cm and 5 m from four large male colonies at Pinnacles reef. Of the 20 female branches placed 5 m from the males none released embryos while 35% (7 of 20 branches) of the branches 〈50cm from males released embryos. These data indicate that simple counts of mature eggs present within female colonics prior to the reproductive season provide a poor estimate of reproductive success in B. ashestinum and that female reproductive success is positively influenced by the close proximity of males.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350865
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  • 3
    Electronic Resource
    Electronic Resource
    Population growth of a gorgonian coral: equilibrium and non-equilibrium sensitivity to changes in life history variables (1991)
    Springer
    Oecologia 86 (1991), S. 503-509 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A size dependent model of population growth of the Caribbean gorgonian Plexaura A is developed based on observed rates of survival, growth and colony fragmentation at a site in the San Blas Islands, Panama. Sensitivity and elasticity analyses indicate that the fate of large colonies has the greatest effect on population growth. Variables which directly affect the generation of large colonies have the next greatest effect on population growth. These variables include the recruitment of large fragments, and the survivorship of colonies in the next smaller size class. Sexual reproduction has an extremely limited ability to affect population growth. Vegetative reproduction has a greater potential effect on growth rates. Environmental conditions regularly change the matrix of transition probabilities which predicts population growth. This keeps the population from approaching its stable size class distribution. Deviations from the stable size class distribution alter sensitivity and elasticity and in this case have the effect of increasing the importance of survivorship of the smallest colonies. Nonequilibrium conditions alter sensitivity analyses and it is important to assess whether populations are at equilibrium and to determine the effects of such deviations on the sensitivity analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318316
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  • 4
    Electronic Resource
    Electronic Resource
    Torsional oscillation patterns in photospheric magnetic features (1993)
    Springer
    Solar physics 143 (1993), S. 19-39 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We analyzed 689 high-resolution magnetograms taken daily with the NSO Vacuum Telescope on Kitt Peak from 1975 to 1991. Motions in longitude on the solar surface are determined by a one-dimensional crosscorrelation analysis of consecutive day pairs. The main sidereal rotation rate of small magnetic features is best fit byω = 2.913(±0.004) − 0.405(±0.027) sin2 φ − 0.422(±0.030) sin4 φ, in µrad s−1, whereφ is the latitude. Small features and the large-scale field pattern show the same general cycle dependence; both show a torsional oscillation pattern. Alternating bands of faster and slower rotation travel from higher latitudes toward the equator during the solar cycle in such a way that the faster bands reach the equator at cycle minimum. For the magnetic field pattern, the slower bands coincide with larger widths of the crosscorrelations (corresponding to larger features) and also with zones of enhanced magnetic flux. Active regions thus rotate slower than small magnetic features. This magnetic torsional oscillation resembles the pattern derived from Doppler measurements, but its velocities are larger by a factor of more than 1.5, it lies closer to the equator, and it leads the Doppler pattern by about two years. These differences could be due to different depths at which the different torsional oscillation indicators are rooted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619094
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  • 5
    Electronic Resource
    Electronic Resource
    Rotation rates of small magnetic features from two- and one-dimensional cross-correlation analyses (1993)
    Springer
    Solar physics 145 (1993), S. 1-10 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present results of an analysis of 628 high-resolution magnetograms taken daily with the NSO Vacuum Telescope on Kitt Peak from 1975 to 1991. Motions in longitude on the solar surface are determined by a two-dimensional cross-correlation analysis of consecutive day pairs. We find that the measured rotation rate of small magnetic features, i.e., excluding active regions, is in excellent agreement with the results of the previous one-dimensional analysis of the same data (Komm, Howard, and Harvey, 1993). The polynomial fits show magnetic torsional oscillations, i.e., a more rigid rotation during cycle maximum and a more differential rotation during cycle minimum, but with smaller amplitudes than the one-dimensional analysis. The full width at half maximum of the cross-correlations is almost constant over latitude which shows that the active regions are effectively excluded. The agreement between the one- and two-dimensional cross-correlation analyses shows that the two different techniques are consistent and that the large-scale motions can be divided into rotational and meridional components that are not affected by each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627979
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  • 6
    Electronic Resource
    Electronic Resource
    Meridional flow of small photospheric magnetic features (1993)
    Springer
    Solar physics 147 (1993), S. 207-223 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the meridional flow of small magnetic features, using high-resolution magnetograms taken from 1978 to 1990 with the NSO Vacuum Telescope on Kitt Peak. Latitudinal motions are determined by a two-dimensional crosscorrelation analysis of 514 pairs of consecutive daily observations from which active regions are excluded. We find a meridional flow of the order of 10 m s−1, which is poleward in each hemisphere, increases in amplitude from 0 at the equator, reaches a maximum at mid-latitude, and slowly decreases poleward. The average observed meridional flow is fit adequately by an expansion of the formM (θ) = 12.9(±0.6) sin(2θ) + 1.4(±0.6) sin(4θ), in m s−1 whereθ is the latitude and which reaches a maximum of 13.2 m s−1 at 39°. We also find a solar-cycle dependence of the meridional flow. The flow remains poleward during the cycle, but the amplitude changes from smaller-than-average during cycle maximum to larger-than-average during cycle minimum for latitudes between about 15° and 45°. The difference in amplitude between the flows at cycle minimum and maximum depends on latitude and is about 25% of the grand average value. The change of the flow amplitude from cycle maximum to minimum occurs rapidly, in about one year, for the 15–45° latitude range. At the highest latitude range analyzed, centered at 52.5°, the flow is more poleward-than-average during minimumand maximum, and less at other times. These data show no equatorward migration of the meridional flow pattern during the solar cycle and no significant hemispheric asymmetry. Our results agree with the meridional flow and its temporal variation derived from Doppler data. They also agree on average with the meridional flow derived from the poleward migration of the weak large-scale magnetic field patterns but differ in the solar-cycle dependence. Our results, however, disagree with the meridional flow derived from sunspots or plages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690713
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  • 7
    Electronic Resource
    Electronic Resource
    The covariance of latitudinal and longitudinal motions of small magnetic features (1994)
    Springer
    Solar physics 151 (1994), S. 15-28 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the covariance of longitudinal and latitudinal motions of small magnetic features after subtracting long-term averages of differential rotation and meridional flow. The covariance is generally interpreted as Reynolds stress and linked to the equatorward transport of angular momentum. Using high-resolution magnetograms taken daily with the NSO Vacuum Telescope on Kitt Peak, we determine large-scale motions by a two-dimensional crosscorrelation analysis of pairs of consecutive daily observations from which active regions are excluded, i.e., we analyze the motions of small magnetic features. In the present work, we focus on 107 day pairs obtained during the year 1988 and on 472 day pairs taken in selected intervals from 1978 to 1990. We find that all covariance values are very small (below 250 m2 s−2), which is about one to two orders of magnitude smaller than the values from sunspot measurements derived by other authors. At active region latitudes, the masking process increases the noise, which increases the chance that the covariances at these latitudes are not significantly different from zero. We find that the results depend strongly on the temporal averaging involved. Daily unaveraged crosscorrelations lead to no apparent correlation between the residual velocities, while in the monthly averages of the 1988 data, we find a covariance of −37 ± 15 m2 s−2 at 45° with a linear correlation of −0.59, which is significantly different from zero and has the right sign for an equatorial transport of angular momentum. When we average over longer time periods, the covariance values decrease again. The annual averages of the 1978–1990 data show both no significant covariances and the smallest errors. These small covariances imply that the motions of small magnetic features do not reflect the transport of angular momentum via the mechanism of Reynolds stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00654078
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  • 8
    Electronic Resource
    Electronic Resource
    Solar surface velocity fields determined from small magnetic features (1990)
    Springer
    Solar physics 130 (1990), S. 295-311 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We describe a method for the analysis of magnetic data taken daily at the Vacuum Telescope at Kitt Peak. In this technique, accurate position differences of very small magnetic features on the solar surface outside active regions are determined from one day to the next by a cross-correlation analysis. In order to minimize systematic errors, a number of corrections are applied to the data for effects originating in the instrument and in the Earth's atmosphere. The resulting maps of solar latitude vs central meridian distance are cross-correlated from one day to the next to determine daily motions in longitude and latitude. Some examples of rotation and meridional motion results are presented. For the months of May 1988 and October–November 1987, we find rotation coefficients A = 2.894 ± 0.011, B = - 0.428 ± 0.070, and C = -0.370 ± 0.077 in μrad s−1 from the expansion ω = A + B sin2φ + C sin4φ, where φ is the latitude. The differential rotation curve for this interval is essentially flat within 20 deg of the equator in these intervals. For the same intervals we find a poleward meridional motion a = 16.0 ± 2.8 m sec -1 from the relation v = a sinφ, where v is the line-of-sight velocity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00156795
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  • 9
    Electronic Resource
    Electronic Resource
    Impact on ammonia volatilization losses of mixing KCl of high pH with urea (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 89-92 
    Details
    ISSN: 1573-0867
    Keywords: KCl ; ammonia volatilization ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ammonia volatilization associated with urea hydrolysis has been shown to be primarily associated with the pH of the soil solution and its buffering ability in the immediate zone of the fertilizer granule. Numerous studies have also shown that these losses can be reduced significantly by the addition of large amounts of KCl with the urea. Because the pH of commercial sources of potash ranges from 6.5 to 9.5, investigations were conducted to determine if the high pH of these K sources had an effect on the ammonia lost from three contrasting soils. Despite large ammonia losses (approximately 50% of N applied) and a significant reduction in loss due to the use of KCl (30%-50% reduction), the experiments showed no effect of potash pH on ammonia loss. It may be concluded that no risk of enhanced ammonia loss can be associated with the use of high-pH potash sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750092
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  • 10
    Electronic Resource
    Electronic Resource
    Phylogenetic relationships of Manihot species revealed by restriction fragment length polymorphism (1994)
    Springer
    Euphytica 76 (1994), S. 227-234 
    Details
    ISSN: 1573-5060
    Keywords: cassava ; Manihot ; RFLP ; phylogenetic relationships ; multilocus probes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two cloned cassava genes (pCAS6, pHNL) and a barley gene (pBLT63) which is highly conserved in higher plants, were evaluated as potential multilocus probes for RFLP analysis of phylogenetic relationships of species within the genus Manihot. For M. rubricaulis, M. chlorosticta and M. esculenta subsp. flabellifolia dendrograms based on 13 probe-restriction enzyme combinations show very little variation between accessions of the same species. A close relationship is demonstrated between the Mexican species M. chlorosticta and the M. esculenta subsp. flabellifolia accessions, which does not support the classification of flabellifolia as a true South American wild species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00022167
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