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  • GEOPHYSICS  (220)
  • ASTROPHYSICS  (198)
  • EARTH RESOURCES AND REMOTE SENSING  (160)
  • FLUID MECHANICS AND HEAT TRANSFER  (63)
  • Life and Medical Sciences  (59)
  • Physics  (55)
  • 1980-1984  (755)
  • 1984  (755)
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  • 1980-1984  (755)
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  • 1
    ISSN: 0148-7280
    Schlagwort(e): spermatozoa ; flow cytometry ; DNA staining ; nuclear morphology ; ultrastructure ; mammals ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The morphological and ultrastructural changes that occur during preparation of porcine, bovine, and murine spermatozoa for flow cytometric quantification of the relative DNA content of the X- and Y-chromosome-bearing sperm populations were examined. Ejaculated spermatozoa from the boar and bull were washed using a series of dimethyl sulfoxide (DMSO) solutions prior to fixation, whereas the epididymal mouse spermatozoa were washed only in phosphate-buffered saline (PBS). Spermatozoa from all three species were then fixed in ethanol and processed for fluorochrome staining by a treatment regimen consisting of sulfhydryl reduction and proteolysis. The processed sperm nuclei were stained for DNA with the fluorochrome, 4′-6-diamidino-2-phenylindole (DAPI) before quantification by flow cytometry. Scanning and transmission electron micrographs of sperm heads taken at various steps of the preparation and staining procedures show 1) that the rigorous washing procedure disrupted the plasma and outer acrosomal membranes, 2) that ethanol fixation resulted in removal of the outer membranes and disintegration of the nuclear envelope, and 3) that thiol and proteolysis treatment removed the remaining cellular organelles including the tail and rapidly induced partial decondensation of the tightly packed chromatin. Sequential micrographs showed that the nuclear matrix of all three species increased in thickness about twofold during the preparation and staining. Consequently, the harsh procedures currently used for quantitative staining of DNA for high-resolution flow cytometric analyses destroy most cellular organelles and thereby prevent simultaneous characterization of DNA content and other sperm cell constituents.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2019-06-28
    Beschreibung: It is pointed out that the redeployment of ISEE 3 from its continuous monitoring of the solar wind in a large orbit about the upstream Lagrangian point to an extended magnetotail orbit has afforded an opportunity for deep-tail passage of October 1982, and in the radial range from 200 to 220 R(E) during the near-apogee part of the second tail passage in January-February 1983. Attention is given to instrumentation and data sets, spacecraft positions, and observational data.
    Schlagwort(e): GEOPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 89; 3855-386
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2019-08-13
    Beschreibung: Dynamics Explorer 1 measurements of intense low-frequency electric and magnetic noise observed at low altitudes over the auroral zone are described. The intensity of both the electric and magnetic fields decreases rapidly with increasing frequency. Most of the energy is at frequencies below the O(+) cyclotron frequency, and some evidence is found for a cutoff or change in spectral slope near that frequency. The magnetic to electric field ratio decreases rapidly with increasing radial distance and also decreases with increasing frequency. The polarization of the electric field in a plane perpendicular to the earth's magnetic field is essentially random. The transverse electric and magnetic fields are closely correlated, with the average Poynting flux directed toward the earth. The total electromagnetic power flow associated with the noise is substantial. Two general models are discussed to interpret these observations, one based on static electric and magnetic fields imbedded in the ionosphere and the other based on Alfven waves propagating along the auroral field lines.
    Schlagwort(e): GEOPHYSICS
    Materialart: AD-A150627 , Journal of Geophysical Research (ISSN 0148-0227); 89; 8971-898
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2011-08-18
    Beschreibung: Using plasma electron and magnetic field measurements from ISEE 3, 220 earth radii from earth, it is found that the magnetotail at that distance is a coherent structure that evidently waves about through distances comparable to its own lateral scale size. For about one-third of the time it was inside the magnetotail, ISEE 3 was in the plasma sheet. During quiet times the plasma sheet is apparently quite thin, but in response to geomagnetic activity it expands, becoming filled with hot plasma flowing tailward at speeds sometimes exceeding 1000 km/sec, and forces the magnetotail cross-section itself to expand. The plasma sheet's expansion is delayed typically by about 30 minutes from the onset of the associated geomagnetic activity (often a clearly identified isolated substorm). The magnetic field in the newly-expanded plasma sheet usually exhibits a few-minute steep northward excursion followed by a more prolonged (and often steep) southward excursion. These are believed to be the signatures of arrival of a plasmoid formed and released near the earth at the onset of the corresponding geomagnetic activity. The discreteness of these plasma releases through the magnetotail and their close association with onsets of geomagnetic activity at earth suggest that they are consequences of spontaneous release, probably by magnetic reconnection, of energy and plasma earlier stored in the magnetotail.
    Schlagwort(e): GEOPHYSICS
    Materialart: Geophysical Research Letters (ISSN 0094-8276); 11; 5-7
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2011-08-19
    Beschreibung: ISEE-3 measurements indicate that a broad mantle-like boundary layer plasma often exists within the distant geomagnetic tail lobes at all latitudes, directly adjacent to the tail magnetopause. The presence of this boundary layer at large tail distances indicates that plasma from the magnetosheath often crosses the magnetopause locally along much of the length of the tail, and is evidence that the tail is 'open'.
    Schlagwort(e): GEOPHYSICS
    Materialart: Geophysical Research Letters (ISSN 0094-8276); 11; 1078-108
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2011-08-18
    Schlagwort(e): GEOPHYSICS
    Materialart: Journal of Geophysical Research (ISSN 0148-0227); 89; 7259-726
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2011-08-18
    Beschreibung: Plasma and field data from the ISEE-3 space probe provide evidence that the lobe-plasma sheet boundary is the central part of the distant geomagnetic tail is often a slow-mode shock. Such shocks are predicted by Petchek's (1964) model of the reconnection. If this model applies, then the ISEE-3 observations place the general location of the reconnection diffusion region closer to the earth than x of about -100 earth radii.
    Schlagwort(e): GEOPHYSICS
    Materialart: Geophysical Research Letters (ISSN 0094-8276); 11; 599-602
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2011-08-18
    Beschreibung: Multitemporal Thematic Mapper, Thematic Mapper Simulator, and detailed ground truth data were collected for a 9- by 11-km sample segment in Webster County, IA, in the summer of 1982. Three dates were acquired each with Thematic Mapper Simulator (June 7, June 23, and July 31) and Thematic Mapper (August 2, September 3, and October 21). The Thematic Mapper Simulator data were converted to equivalent TM count values using TM and TMS calibration data and model based estimates of atmospheric effects. The July 31, TMS image was compared to the August 2, TM image to verify the conversion process. A quantitative measure of proportion estimation variance (Fisher information) was used to evaluate the corn/soybeans separability for each TM band as a function of time during the growing season. The additional bands in the middle infrared allowed corn and soybeans to be separated much earlier than was possible with the visible and near-infrared bands alone. Using the TM and TMS data, temporal profiles of the TM principal components were developed. The greenness and brightness exhibited behavior similar to MSS greenness and brightness for corn and soybeans.
    Schlagwort(e): EARTH RESOURCES AND REMOTE SENSING
    Materialart: IEEE Transactions on Geoscience and Remote Sensing (ISSN 0196-2892); GE-22; 312-318
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2019-06-28
    Beschreibung: Details of an investigation of a lone plasmoid encountered by the ISEE-3 spacecraft in February 1983 are reported. ISEE-3 was then at 217 earth radii distance, in the magnetosheath, and had entered the magnetotail. Intense energetic particle, plasma and magnetic field fluctuations were detected, indicating a large electron flux moving tailward, a suprathermal proton flux, a jump in electron temperature, and inverse signatures of an increasing magnetic field. Closed magnetic field lines were also detected as were IMF field lines around the plasmoid and open field lines connecting the earth with space. The hot particles in the plasmoid are concluded to have been magnetically confined in a boundary one earth radius thick. An earthward directed beam was also detected and was found to balance the tailward flux. The origin and characteristics of the beam were not discerned.
    Schlagwort(e): GEOPHYSICS
    Materialart: Geophysical Research Letters (ISSN 0094-8276); 11; 1046-104
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2019-06-28
    Beschreibung: Particle data have been acquired by the 1981-025 and 1982-019 spacecraft at geosynchronous orbit, as well as ISEE-1 in the near earth geomagnetic tail, and ISEE-3 in the distant geomagnetic tail. These observations are supplemented by ground-based magnetograms from near local midnight stations. Attention is given to a substorm recovery phase, and to observations of ion beams at the plasma sheet boundary in the near earth and distant tail, respectively, which are found to flow in opposite directions.
    Schlagwort(e): GEOPHYSICS
    Materialart: Geophysical Research Letters (ISSN 0094-8276); 11; 1034-103
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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