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  • 1
    Electronic Resource
    Electronic Resource
    An early extrasolar planetary system revealed by planetesimal belts in β Pictoris (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 431 (2004), S. 660-663 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] β Pictoris (β Pic) is a main-sequence star with an edge-on dust disk that might represent a state of the early Solar System. The dust does not seem to be a remnant from the original protoplanetary disk, but rather is thought to have been generated from large bodies like planetesimals ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature02948
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  • 2
    Electronic Resource
    Electronic Resource
    Study of silicon-hydrogen bonds at an amorphous silicon/silicon nitride interface using infrared attenuated total reflection spectroscopy (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 1942-1944 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Silicon-hydrogen bonding structures at a hydrogenated amorphous silicon (a-Si:H)/silicon nitride (SiN) interface have been investigated using Fourier transform infrared attenuated total reflection (FTIR-ATR). Depositing a SiN overlayer markedly decreased the higher hydrides, which consist of SiHn (n=2,3) bonds, on the a-Si:H surface. The low density of higher hydrides at the resulting SiN-on-a-Si:H interface may be due to plasma-enhanced extraction or a transfer of the growing surface. By contrast, at an a-Si:H-on-SiN interface, the higher hydrides density is about 8.1×1014 cm−2. We believe this large amount of hydrogen at the a-Si:H-on-SiN interface relaxes strained bonds at the interface. In both the SiN-on-a-Si:H interface and the a-Si:H-on-SiN interface, hydrogen is implanted in the underlayer during the deposition of the overlayer. Our results indicate the structure of underlayer near the interface is strongly affected by the deposition of the overlayer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.107158
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  • 3
    Electronic Resource
    Electronic Resource
    5S Ribosomal RNA Sequence of Pneumocystis carinii and its Phylogenetic Association with “Rhizopoda/Myxomycota/Zygomycota Group” (1989)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 36 (1989), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The cytoplasmic 5S ribosomal RNA sequence from Pneumocystis carinii was determined and compared with those of 382 eukaryotes and an evolutionary tree was constructed to establish the phylogenetic position of Pneumocystis. The data suggest that Pneumocystis is associated with the Rhizopoda/Myxomycota/ Zygomycota group but not with common fungi, such as Ascomycota or Basidiomycota, nor with other protozoa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1989.tb05812.x
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  • 4
    Electronic Resource
    Electronic Resource
    Periodic activity of Comet Bradfield 1987s (1989)
    Springer
    Earth, moon and planets 44 (1989), S. 141-147 
    Details
    ISSN: 1573-0794
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A periodic brightness variation of about 6 days was found by applying maximum entropy method to the visual brightness of Comet Bradfield 1987s. This activity was clearly apparent in January of 1988. No other outstanding period was detected. This suggests that the period of the rotation or precession of the nucleus is about 6 days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00056313
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  • 5
    Electronic Resource
    Electronic Resource
    Activity Profile of the Sextantid Meteor Shower (1997)
    Springer
    Earth, moon and planets 77 (1997), S. 83-91 
    Details
    ISSN: 1573-0794
    Keywords: Meteors: Individual (Sextantids), ; radio observations of meteors ; orbital evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The detailed activity profile of the Sextandids - one of the day-time meteor showers - is poorly known and still unclear. Using the forward-scatter radio technique we have successfully been able to obtain further detailed overall activity profile of the Sextantids for seven consecutive years: 1991–1997. Analysis confirmed the Sextantid activity duration in solar longitude (J2000) of at least 184–193° and the maximum solar longitude at 188.35 ± 0.10° with a full width at half maximum (FWHM) of 2.0 ± 0.2°. Performing the numerical integrations, we also substantiated a possibility of the association between Apollo-type asteroid (3200) Phaethon and the Sextantids. Furthermore, we roughly estimated relative maximum flux rate of Sextantids : Geminids as 1 : 3 amplitude ratio. Depending upon the flux rates and the time lags of the orbital evolution with Phaethon, we conclude that the Sextantids are at a more progressive stage of orbital evolution than the Geminids if both meteor streams are really associated with Phaethon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006266904233
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  • 6
    Electronic Resource
    Electronic Resource
    CCD surface photometry of an outburst of P/Schwassmann-Wachmann 1 comet (1991)
    Springer
    Earth, moon and planets 52 (1991), S. 15-25 
    Details
    ISSN: 1573-0794
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We have observed an outburst of P/Schwassmann-Wachmann 1 (SW1) on 25–26 July 1987 using a CCD imager with R-band filter. The total brightness increased from 15.5 mg (25d) to 14.4 mag (26d) during tabout 24 hrs. The southward elongated coma of 25″ was detected. The radial surface brightness (B) profiles are plotted against apparent distance p from the nucleus. The logarithmic derivative k = d ln B/d ln p for the inner coma is found to have steepened from k = −1.40 (25d) to k = −1.69 (26d), whereas that for the outer coma showed no appreciable change (k = −1.19 ~ −1.22). The ellipticity of the isophotal contour of the inner coma increased about 15% fro 25d to 6d. It is concluded that the scale of this outburst was smaller than the typical ones whose magnitude change is 5–8 mag. From recent findings on the outburst natur eof SW1 including ours, a working model of the nuclues is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00113828
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  • 7
    Electronic Resource
    Electronic Resource
    First Results of High-Definition TV Spectroscopic Observations of the 1999 Leonid Meteor Shower (1998)
    Springer
    Earth, moon and planets 82-83 (1998), S. 369-377 
    Details
    ISSN: 1573-0794
    Keywords: Comet 55P/Tempel-Tuttle ; high definition TV ; interplanetary dust ; Leonids 1999 ; meteor spectroscopy ; meteors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract During the 1999 Leonids, an intensified HDTV camera was used for slitless meteor spectroscopy at visible and near-UV wavelengths in three night flights of the Leonid Multi-instrument Aircraft Campaign. The IIDTV system provided a high dynamic range (digital 10-bit) and a wide field of view of 37 × 21 degrees. The maximum spectral sensitivity is at 405 nm, while the resolving power of the spectrograph was λ/Δλ ∼ 250. Here, we report on the results for one particularly nice spectrum from a Leonid meteor at 03:24:40 UT. Numerous atomic emission lines of magnesium and iron were detected, with an excitation temperature of T = 5,000 ± 1,000. It is confirmed that sodium is released from the meteoroid earlier than iron and magnesium, just as in meteors of the 1998 Leonid shower. Rovibrational bands of N2 dominate the spectrum in the visible and near-IR. We searched for CN band emission at 389 nm, but could not detect it due to the overlap of numerous iron lines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017055120356
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  • 8
    Electronic Resource
    Electronic Resource
    Measurement of the solar wind velocity with cometary tail rays (1991)
    Springer
    Solar physics 132 (1991), S. 395-407 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Cometary tail rays are traces of the magnetic fields caught in the cometary magnetosphere. Time variations of these rays give us a way to measure the local solar wind velocity at the location of a comet. We introduce a simple method for determining the radial velocity of the solar wind by observing the ray folding motion, and show an example of its application to comet P/Brorsen-Metcalf 1989o, which resulted in 340 ± 35 km s−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00152295
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  • 9
    Electronic Resource
    Electronic Resource
    Cytochemical and ultrastructural examination of apoptotic odontoclasts induced by bisphosphonate administration (2000)
    Springer
    Cell & tissue research 301 (2000), S. 375-387 
    Details
    ISSN: 1432-0878
    Keywords: Odontoclast Deciduous teeth Apoptosis Bisphosphonate Ultrastructure Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Since odontoclasts share similar characteristics with osteoclasts, this study has examined whether odontoclasts exhibit cytological alteration after treatment with bisphosphonate, which induces apoptosis of osteoclasts. After the administration of bisphosphonate to 6-day-old rabbits, many odontoclasts detached from the dentine surface of the deciduous teeth, resulting in the reduction of tartrate-resistant acid phosphatase (TRAPase) and immunoreactivity for cathepsin K. Transmission electron microscopy revealed a number of odontoclasts showing poorly developed or a lack of ruffled borders, a Golgi apparatus markedly reduced in size, and numerous cytoplasmic vesicles. The bisphosphonate-treated odontoclasts displayed fragmented DNA in the pyknotic nuclei evidenced by terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick-end labeling, indicating that bisphosphonate can induce apoptosis of the odontoclasts. Ultrastructural observations of the apoptotic odontoclasts revealed condensed heterochromatin at the margin of the nuclear envelope, assembled arrays of rough endoplasmic reticulum, and many vacuoles and vesicles. Some apoptotic odontoclasts showed ladder-like structures between the adjacent nuclear envelopes, enlargement of the nuclear envelopes, and the formation of a ribosome-like granular structure in the nuclei. Thus, odontoclasts are able to undergo apoptosis after bisphosphonate treatment; this results in cytological alterations, including reduced resorption activity and the inhibition of protein synthesis/transport as indicated by the diminished TRAPase and cathepsin K and the poorly developed Golgi apparatus, respectively. Nuclear alteration as evidenced by the appearance of ladder-like and ribosome-like structures was characteristic of apoptotic odontoclasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410000242
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