ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (5)
  • 1990-1994  (5)
Collection
Source
Keywords
Years
Year
  • 1
    facet.materialart.
    Unknown
    Amino acid racemization in amber-entombed insects: implications for DNA preservation (1994)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: DNA depurination and amino acid racemization take place at similar rates in aqueous solution at neutral pH. This relationship suggests that amino acid racemization may be useful in accessing the extent of DNA chain breakage in ancient biological remains. To test this suggestion, we have investigated the amino acids in insects entombed in fossilized tree resins ranging in age from 〈100 years to 130 million years. The amino acids present in 40 to 130 million year old amber-entombed insects resemble those in a modern fly and are probably the most ancient, unaltered amino acids found so far on Earth. In comparison to other geochemical environments on the surface of the Earth, the amino acid racemization rate in amber insect inclusions is retarded by a factor of 〉10(4). These results suggest that in amber insect inclusions DNA depurination rates would also likely be retarded in comparison to aqueous solution measurements, and thus DNA fragments containing many hundreds of base pairs should be preserved. This conclusion is consistent with the reported successful retrieval of DNA sequences from amber-entombed organisms.
    Keywords: Geosciences (General)
    Type: Geochimica et cosmochimica acta (ISSN 0016-7037); Volume 58; 14; 3131-5
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Decentralized-feedback pole placement of linear systems (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: A projectile product spaces model is used to analyze decentralized systems. The degree of the pole placement map is computed. The conditions under which the degree is odd are also given. Twin lift systems are studied. It is proved that the poles of a twin lift system can be assigned to any values by local static and local dynamic feedback laws if and only if the system is jointly controllable.
    Keywords: CYBERNETICS
    Type: International Journal of Control (ISSN 0020-7179); 55; 511-518
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Gradient drift eigenmodes in the equatorial electrojet (1994)
    In:  Other Sources
    Details
    Publication Date: 2019-08-28
    Description: The problem of kilometer-scale irregularities in the daytime equatorial electrojet is revisited by means of an eigenmode analysis of the gradient drift instability. Realistic physical parameters are used, including the modeled altitude variations of ion and electron collision frequencies and mobilities. The full fourth-order system of two coupled differential equations (each of second order) for the denisty and electrostatic potential perturbations is solved numerically by a relaxation technique. Under some approximations, the fourth-order system can be shown to reduce to a second-order differential equation for the perturbed potential or density. The latter is solved using a shooting technique and provides initial guesses for numerical solutions to the full problem. It is shown that the linear growth rate peaks for kilometer-scale waves, contrary to the findings of recent initial-value studies. This occurs because the equilibrium velocity shear is much more effective as a damping mechanism for short-wavelength modes than it is for the longer, kilometer-scale modes. These results provide a natural qualitative explanation for the observed dominance of kilometer-scale structures in the daytime electrojet spectrum.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 99; A7; p. 13,219-13,226
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Modeling of video traffic in packet networks, low rate video compression, and the development of a lossy+lossless image compression algorithm (1992)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: During this reporting period we have worked on three somewhat different problems. These are modeling of video traffic in packet networks, low rate video compression, and the development of a lossy + lossless image compression algorithm, which might have some application in browsing algorithms. The lossy + lossless scheme is an extension of work previously done under this grant. It provides a simple technique for incorporating browsing capability. The low rate coding scheme is also a simple variation on the standard discrete cosine transform (DCT) coding approach. In spite of its simplicity, the approach provides surprisingly high quality reconstructions. The modeling approach is borrowed from the speech recognition literature, and seems to be promising in that it provides a simple way of obtaining an idea about the second order behavior of a particular coding scheme. Details about these are presented.
    Keywords: COMPUTER PROGRAMMING AND SOFTWARE
    Type: NASA-CR-190546 , NAS 1.26:190546
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Ballooning stability of anisotropic, rotating plasmas (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: The linearized equation of motion is given in a Lagrangian representation for a rotating plasma with anisotropic pressure. A WKB theory is developed for large-n ballooning modes in an axisymmetric configuration with field-aligned and rigid toroidal flows. In the presence of field-aligned flows, it is shown that a resonance occurs which is strongly suggestive of a generalized mirror instability. In the presence of toroidal rotation, a possible stabilizing effect is identified for P(normal) greater than P(parallel). Finally, as a special case of the theory, the necessary and sufficient conditions for stability in a static, anisotropic plasma are obtained.
    Keywords: PLASMA PHYSICS
    Type: Physics of Fluids B (ISSN 0899-8221); 2; 2346-235
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...