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  • 1
    Electronic Resource
    Electronic Resource
    Steroid Production by Callus and Cell Suspension Cultures of Solanum aviculare (1984)
    s.l. : American Chemical Society
    Journal of natural products 47 (1984), S. 373-376 
    Details
    ISSN: 1520-6025
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/np50032a024
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  • 2
    Electronic Resource
    Electronic Resource
    The Biochemistry of Antigen-Specific T-Cell Factors (1983)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Immunology 1 (1983), S. 423-438 
    Details
    ISSN: 0732-0582
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.iy.01.040183.002231
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  • 3
    Electronic Resource
    Electronic Resource
    X-ray and Hα observations of a filament-disappearance flare: An empirical analysis of the magnetic field configuration (1981)
    Springer
    Solar physics 70 (1981), S. 335-350 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A flare event occurred which involved the disappearance of a filament near central meridian on 29 August 1973. The event was well observed in X-rays with the AS & E telescope on Skylab and in Hα at BBSO. It was a four-ribbon flare involving both new and old magnetic inversion lines which were roughly parallel. The Hα, X-ray, and magnetic field data are used to deduce the magnetic polarities of the Hα brightenings at the footpoints of the brightest X-ray loops. These magnetic structures and the preflare history of the region are then used to argue that the event involved a reconnection of magnetic field lines rather than a brightening in place of pre-existing loops. The simultaneity of the Hα brightening onsets in the four ribbons and the apparent lack of an eruption of the filament are consistent with this interpretation. These observations are compared to other studies of filament disappearances. The preflare structures and the alignment of the early X-ray flare loops with the Hα filament are consistent with the schematic picture of a filament presented first by Canfield et al. (1974).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151338
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  • 4
    Electronic Resource
    Electronic Resource
    Kinematical analysis of flare spray ejecta observed in the corona (1981)
    Springer
    Solar physics 73 (1981), S. 341-361 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The mass ejection event on 17 January 1974 was a classsic spray associated with a flare from an over the limb region. The structure of the accompanying coronal transient was typical of well-observed mass ejections, with coronal loops and a forerunner racing ahead of the rising prominence. Observations in Hα, soft X-ray, white light and radio wavelengths allowed us to track both cool (T e∼104 K) and hot (T e〉106 K) material from limb de-occultation to 6R ⊙. We determined the kinematics and thermodynamics of the internal material, and the overall mass and energy budget of the event. The majority of the mass and energy was linked with coronal material, but at least 20% of the ejected mass originated as near-surface prominence material. We conclude that the upper part of the prominence was being continuously heated to coronal temperatures as it rose through the corona. Above ∼2R ⊙ nearly all of the material was completely ionized. The primary acceleration of the prominence occurred below 3.5 × 104 km with all of the material exhibiting constant velocity above 1.5R ⊙. We found evidence that a moving type IV burst, indicative of strong magnetic fields, was associated with the upper part of the prominence. Our observations suggest that both the cool and hot material were acted upon by a similar, continuous force(s) to great heights and over a long time interval. We find that the observations are most consistent with magnetic propulsion models of coronal transients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151686
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  • 5
    Electronic Resource
    Electronic Resource
    The spatial distribution of 6 centimeter gyroresonance emission from a flaring X-ray loop (1984)
    Springer
    Solar physics 92 (1984), S. 271-281 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We compare simultaneous high resolution soft X-ray and 6 cm images of the decay phase of an M3 X-ray flare in Hale Region 16413. The photographic X-ray images were obtained on an AS & E sounding rocket flown 7 November, 1979, and the 6 cm observations were made with the VLA. The X-ray images were converted to arrays of line-of-sight emission integrals and average temperature throughout the region. The X-ray flare structure consisted of a large loop system of length ∼ 1.3 arc min and average temperature ∼8 × 106 K. The peak 6 cm emission appeared to come from a region below the X-ray loop. The predicted 6 cm flux due to thermal bremsstrahlung calculated on the basis of the X-ray parameters along the loop was about an order of magnitude less than observed. We model the loop geometry to examine the expected gyroresonance absorption along the loop. We find that thermal gyroresonance emission requiring rather large azimuthal or radial field components, or nonthermal gyrosynchrotron emission involving continual acceleration of electrons can explain the observations. However, we cannot choose between these possibilities because of our poor knowledge of the loop magnetic field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00157251
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  • 6
    Electronic Resource
    Electronic Resource
    X-Ray and microwave observations of active regions (1983)
    Springer
    Solar physics 85 (1983), S. 267-283 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We compare coordinated, high spatial resolution (2–3 arc sec) observations at 6 cm and in soft X-rays with photospheric magnetograms and optical filtergrams of two active regions. The correspondence of the brightest centimetric components in these regions with coronal loops, sunspots and pores, chromospheric structures and the photospheric magnetic field was determined. Our principal results are: The association between the microwave components and coronal X-ray and photospheric magnetic field structures is complex; in general X-ray emission was not associated with the microwave components. A majority of the components were not associated with sunspots, although the brightest (T b ≥ 4 × 106 K) components overlay regions of strong photospheric field or high field gradients. Several of the components coincided with the apparent bases of shorter coronal loops and 4 with the tops of X-ray loops. The X-ray and magnetic field observations are used to constrain possible centimetric emission mechanisms. Thermal bremsstrahlung can not be a significant contributor to this bright microwave emission. Thermal gyro-resonance absorption is consistent with some of the observations, but untenable for those components which are bright in microwaves, lack X-ray emission, and overlie regions of weak magnetic field. As an explanation for the brightest (T b ≥ 4 × 106 K) components, the g-r theory requires coronal loops with significant currents but very low densities. Alternatively, a nonthermal mechanism implies that the emission arises from the transition region and suggests that discrete regions of continuous particle acceleration may be common in active regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00148654
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  • 7
    Electronic Resource
    Electronic Resource
    A demonstration of ocean acoustic tomography (1982)
    [s.l.] : Nature Publishing Group
    Nature 299 (1982), S. 121-125 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Over the past decade oceanographers have become increasingly aware of an intense and compact ocean ‘mesoscale’ eddy structure (the ocean weather) that is superimposed on a generally sluggish large-scale circulation (the ocean climate). Traditional ship-based observing systems are not ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/299121a0
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  • 8
    Electronic Resource
    Electronic Resource
    Macro-habitat patch structure, environmental harshness, and Marmota flaviventris (1981)
    Springer
    Behavioral ecology and sociobiology 8 (1981), S. 175-182 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Social behavior of 15 colonies of Yellow-bellied Marmots was studied at sites differing in both elevation (plant growing season length) and patch structure (density and spacing of suitable colony sites in large blocks of habitat) from 1976 through 1978. Colonies were typically composed of family groups. In low elevation colonies, offspring dispersed at the end of the juvenile year. In all high elevation areas, offspring dispersed as yearlings, and parent-offspring and sibling interactions during the juvenile year were highly amicable. In high elevation areas in continuous habitat, dispersal by yearlings occurred with no agonistic interactions. In high elevation areas with patchy habitat, however, brief but intense periods of extremely agonistic sibling and parent-offspring interactions occurred immediately prior to dispersal of yearlings. Social behavior and dispersal are uncorrelated with elevation, plant growing season length, or available foraging time. Social interaction among relatives in marmot colonies is amicable when other suitable colony sites are located nearby; in these areas, dispersal occurs without any antagonism. Agonistic behavior occurs only in areas with a patchy distribution of suitable colony sites. At these sites, dispersal occurs only after periods of extreme antagonism. Further, those offspring who do not disperse from the colony site are the ones who dominate and initiate agonistic interactions with their siblings. The large-scale structure of the habitat influences the propensity of the individual to disperse. When the animal is reluctant to disperse because of a combination of high transit difficulty and low desirability of a new site, angonistic social interactions with relatives force dispersal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299827
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  • 9
    Electronic Resource
    Electronic Resource
    Coronal loops and active region structure (1981)
    Springer
    Solar physics 69 (1981), S. 99-118 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We intercompared synoptic Hα, Ca K, magnetograph and Skylab soft X-ray and EUV data for the purpose of identifying the basic coronal magnetic structure of loops in a ‘typical’ active region and studying its evolution. We focussed on a complex of activity in July 1973, especially McMath 12417. Our principal results are: (1) Most of the brightest loops connected the bright f plage to either the sunspot penumbra or to p satellite spots; no non-flaring X-ray loops end in umbrae; (2) short, bright loops had one or both ends in regions of emergent flux, strong fields or high field gradients; (3) stable, strongly sheared loop arcades formed over filaments; (4) EFRs were always associated with compact X-ray arcades; and (5) loops connecting to other active regions had their bases in outlying plage of weak field strength in McM 417 where Hα fibrils marked the direction of the loops. We conclude that a typical loop brightens in response to magnetic field activity at its feet, which heats the plasma. This suggests that the loop acts as a trap for gas convected from its base.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00151258
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  • 10
    Electronic Resource
    Electronic Resource
    Observations of the reappearance of polar coronal holes and the reversal of the polar magnetic field (1984)
    Springer
    Solar physics 92 (1984), S. 109-132 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We examine observations relating to the evolution of the polar magnetic field around sunspot maximum, when the net polar flux reverses polarity and coronal holes redevelop around the poles. Coronal hole observations during the last two solar maxima are examined in detail. Long-term averages of the latitudinal dependence of the photospheric magnetic field and the evolutionary pattern of the polar crown filaments are used to trace the poleward motion of the reversal of the large-scale surface field, and are compared to the redevelopment of the polar holes. The polar holes evolve from small, mid-latitude holes of new-cycle polarity which expand poleward until they join and cover the pole. We find that the appearance of these mid-latitude holes, the peak of flux emergence at low latitudes, and the polar polarity reversal all occur within a few solar rotations. Lagging 6 months to 1 1/2 yr after this time, the polar crown disappears and the polar holes redevelop. These results are examined in the context of phenomenological models of the solar cycle. We believe the following results in particular must be accounted for in successful models of the solar cycle: (1) The process of polarity reversal and redevelopment of the polar holes is discontinuous, occurring in 2 or 3 longitude bands, with surges of flux of old-cycle polarity interrupting the poleward migration of new-cycle flux. There is a persistent asymmetry in these processes between the two hemispheres; the polarity reversal in the two hemispheres is offset by 6 months to 1 1/2 yr. (2) Contrary to the Babcock hypothesis, the polar crown disappears months after the magnetic polar reversal. We suggest one possible scenario to explain this effect. (3) Our observations support suggestions of a poleward meridional flow around solar maximum that cannot be accounted for by Leighton-type diffusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00157239
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