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  • 1
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    Autophagy genes are essential for dauer development and life-span extension in C. elegans (2003)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2003-09-06
    Description: Both dauer formation (a stage of developmental arrest) and adult life-span in Caenorhabditis elegans are negatively regulated by insulin-like signaling, but little is known about cellular pathways that mediate these processes. Autophagy, through the sequestration and delivery of cargo to the lysosomes, is the major route for degrading long-lived proteins and cytoplasmic organelles in eukaryotic cells. Using nematodes with a loss-of-function mutation in the insulin-like signaling pathway, we show that bec-1, the C. elegans ortholog of the yeast and mammalian autophagy gene APG6/VPS30/beclin1, is essential for normal dauer morphogenesis and life-span extension. Dauer formation is associated with increased autophagy and also requires C. elegans orthologs of the yeast autophagy genes APG1, APG7, APG8, and AUT10. Thus, autophagy is a cellular pathway essential for dauer development and life-span extension in C. elegans.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Melendez, Alicia -- Talloczy, Zsolt -- Seaman, Matthew -- Eskelinen, Eeva-Liisa -- Hall, David H -- Levine, Beth -- CA84254/CA/NCI NIH HHS/ -- RR 12596/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2003 Sep 5;301(5638):1387-91.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, Columbia University College of Physicians & Surgeons, 630 West 168th Street, New York, NY 10032, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12958363" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Animals, Genetically Modified ; Apoptosis Regulatory Proteins ; Autophagy/*genetics ; Caenorhabditis elegans/*genetics/*growth & development/metabolism/ultrastructure ; Caenorhabditis elegans Proteins/chemistry/*genetics/metabolism/physiology ; Genes, Fungal ; *Genes, Helminth ; Humans ; Longevity ; Membrane Proteins ; Morphogenesis ; Mutation ; Phagosomes/ultrastructure ; Phenotype ; Proteins/chemistry/genetics/physiology ; RNA Interference ; Receptor, Insulin/genetics/metabolism ; Recombinant Fusion Proteins/metabolism ; Saccharomyces cerevisiae/genetics/physiology ; Signal Transduction ; Vesicular Transport Proteins
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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    PAPER CURRENT
  • 2
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    RFI at L-band in Synthetic Aperture Radiometers (2003)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: The spectral window at 1.413 GHz (L-band), set aside for passive use only, is critical for passive remote sensing of the earth from space. It is the largest spectral window available in the long wavelength end of the microwave spectrum where measurements are needed to monitor parameters of the surface such as soil moisture and sea surface salinity. The sensitivity to these parameters is rapidly lost at higher frequencies and is compromised by the ionosphere and antenna size at lower frequencies. Instruments for remote sensing from space in this spectral window are being developed by NASA (Aquarius) and ESA (SMOS) and are expected to be in orbit in a few years (2006). Although the band at 1.413 GHz is protected for passive use, RFI is a common problem. For example, the synthetic aperture radiometer, ESTAR (L-band, Horizontal polarization), has frequently experienced problems with RFI. During the Southern Great Plains Experiments (1997 and 1999), ESTAR experienced RFI significant enough to warrant changes in flight lines. The largest sources of RFI were identified as originating in airports and a likely source is air traffic control radar. In experiments in the vicinity of Richmond, VA, RFI in the form of periodic spikes was recorded, again suggestive of radar. However, in most cases the sources of the RFI are unknown. RFI is a sufficiently common problem that the first step in processing ESTAR data is a screening for RFI (a filter is used to detect large, rapid changes in brightness). Recently, measurements have been made with a new synthetic aperture radiometer, 2D-STAR. Examples of RFI observed simultaneously with ESTAR and the new synthetic aperture radiometer will be presented. 2D-STAR is an airborne instrument designed to develop the technology of aperture synthesis in two dimensions. It employs dual polarized patch antennas arranged in a cross configuration (+). Synthesis in two dimensions offers the potential for optimal thinning, but because of the wide field of view of the individual antennas it is potentially more susceptible to RFI. The 2D-STAR instrument was flown together with ESTAR in a series of test flights on the NASA P-3 aircraft near the Wallops Flight Facility during the summer of 2002. Both instruments experienced RFI over common locations. Examples will be presented and a comparison between instruments presented.
    Keywords: Communications and Radar
    Type: IGARSS Conference; Jul 21, 2003 - Jul 25, 2003; Toulouse; France
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    L-band Dielectric Constant Measurements of Seawater (Oral presentation and SMOS Poster) (2003)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: This paper describes a resonant cavity technique for the measurement of the dielectric constant of seawater as a function of its salinity. Accurate relationships between salinity and dielectric constant (which determines emissivity) are needed for sensor systems such as SMOS and Aquarius that will monitor salinity from space in the near future. The purpose of the new measurements is to establish the dependence of the dielectric constant of seawater on salinity in contemporary units (e.g. psu) and to take advantage of modern instrumentation to increase the accuracy of these measurements. The measurement device is a brass cylindrical cavity 16cm in diameter and 7cm in height. The seawater is introduced into the cavity through a slender glass tube having an inner diameter of 0.1 mm. By assuming that this small amount of seawater slightly perturbs the internal fields in the cavity, perturbation theory can be employed. A simple formula results relating the real part of the dielectric constant to the change in resonant frequency of the cavity. In a similar manner, the imaginary part of the dielectric constant is related to the change in the cavity s Q. The expected accuracy of the cavity technique is better than 1% for the real part and 1 to 2% for the imaginary part. Presently, measurements of methanol have been made and agree with precision measurements in the literature to within 1% in both real and imaginary parts. Measurements have been made of the dielectric constant of seawater samples from Ocean Scientific in the United Kingdom with salinities of 10, 30, 35 and 38 psu. All measurements were made at room temperature. Plans to make measurements at a range of temperatures and salinities will be discussed.
    Keywords: Oceanography
    Type: IGARSS Conference; Jul 21, 2003 - Jul 25, 2003; Toulouse; France
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    A Radar/Radiometer Instrument for Mapping Soil Moisture and Ocean Salinity (2003)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The RadSTAR instrument combines an L-band, digital beam-forming radar with an L-band synthetic aperture, thinned array (STAR) radiometer. The RadSTAR development will support NASA Earth science goals by developing a novel, L-band scatterometer/ radiometer that measures Earth surface bulk material properties (surface emissions and backscatter) as well as surface characteristics (backscatter). Present, real aperture airborne L-Band active/passive measurement systems such as the JPUPALS (Wilson, et al, 2000) provide excellent sampling characteristics, but have no scanning capabilities, and are extremely large; the huge JPUPALS horn requires a the C-130 airborne platform, operated with the aft loading door open during flight operation. The approach used for the upcoming Aquarius ocean salinity mission or the proposed Hydros soil mission use real apertures with multiple fixed beams or scanning beams. For real aperture instruments, there is no upgrade path to scanning over a broad swath, except rotation of the whole aperture, which is an approach with obvious difficulties as aperture size increases. RadSTAR will provide polarimetric scatterometer and radiometer measurements over a wide swath, in a highly space-efficient configuration. The electronic scanning approaches provided through STAR technology and digital beam forming will enable the large L-band aperture to scan efficiently over a very wide swath. RadSTAR technology development, which merges an interferometric radiometer with a digital beam forming scatterometer, is an important step in the path to space for an L-band scatterometer/radiometer. RadSTAR couples a patch array antenna with a 1.26 GHz digital beam forming radar scatterometer and a 1.4 GHz STAR radiometer to provide Earth surface backscatter and emission measurements in a compact, cross-track scanning instrument with no moving parts. This technology will provide the first L-band, emission and backscatter measurements in a compact aircraft instrument and will be ideally suited to large apertures, possibly at GEO, and could possibly be implemented on a swarm of micro-satellites. This instrument will have wide application for validation studies, and will have application for other microwave frequencies.
    Keywords: Oceanography
    Type: 31st Conference on Radar Meteorology; Aug 06, 2003 - Aug 12, 2003; Seattle, WA; United States
    Format: text
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    NASA TECHNICAL REPORTS
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