18,135 research outputs found
LANDSAT-4 sensor performance
Preflight and in-orbit sensor and data measurements indicate that TM meets or exceeds most specifications. Measured spectral band edges meet instrument specifications in 12 out of 14 cases; there is ample dynamic range. The signal-to-noise ratio exceeds specifications, except for band 3, channel 4; and band 7 channel 7 is very noisy but still meets specifications. The modulation transfer function of channel 4, band 2, is smaller than specified. Registration errors between the primary focal plane (PFP) and the cold focal plane (CFP) are about 0.75 pixels along-scan and 0.2 pixels across scan. Forward and reverse scan discontinuities, are well within ground-processing capabilities to rectify. Instrument gain variability, up to 7% for band 5, requires use of the internal calibration (IC) system to assure radiometric accuracy. Preliminary applications evaluation of image contents indicates that TM provides much better definition of edges than MSS
TM digital image products for applications
Computer compatible tapes (CCTs) of LANDSAT 4 thematic mapper (TM) digital image products are compared and reviewed. The following tape formats are discussed: (1) raw band-sequential data (CCT-BT); (2) calibrated data (CCT-AT); and (3) geometrically resampled data (CCT-PT). Each format represents different steps in the process of producing fully corrected TM data. The CCT-BT images are uncorrected radiometrically or geometrically, CCT-AT data are radiometrically calibrated, and CCT-PT images are both radiometrically and geometrically corrected
TM digital image products for applications
The image characteristics of digital data generated by LANDSAT 4 thematic mapper (TM) are discussed. Digital data from the TM resides in tape files at various stages of image processing. Within each image data file, the image lines are blocked by a factor of either 5 for a computer compatible tape CCT-BT, or 4 for a CCT-AT and CCT-PT; in each format, the image file has a different format. Nominal geometric corrections which provide proper geodetic relationships between different parts of the image are available only for the CCT-PT. It is concluded that detector 3 of band 5 on the TM does not respond; this channel of data needs replacement. The empty bin phenomenon in CCT-AT images results from integer truncations of mixed-mode arithmetric operations
Scaling study of Si and strained Si n-MOSFETs with different high-k gate stacks
Using ensemble Monte Carlo device simulations, this paper studies the impact of interface roughness and soft-optical phonon scattering on the performance of sub-100nm Si and strained Si MOSFETs with different high-k gate stacks. Devices with gate lengths down to 25nm have been investigated
The Infra‐Red Absorption Spectrum of Mono‐Deutero‐Ethane under High Resolution
The infra‐red spectrum of C2H5D has been investigated under high resolution. As expected, the bands corresponding to degenerate vibrations of C2H6 are split into two components with oscillations in the symmetry plane and normal to the symmetry plane respectively. Analogues of several of the inactive C2H6 frequencies have also been observed, including a pair at 1122 cm−1 and 1159 cm−1 corresponding to a Raman line of ordinary ethane which has been predicted at about 1170 cm−1 but has not as yet been found.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69718/2/JCPSA6-17-2-182-1.pd
Characterization and Testing of a Micro-g Whispering Gallery Mode Optomechanical Accelerometer
Navigation, bio-tracking devices and gravity gradiometry are amongst the
diverse range of applications requiring ultrasensitive measurements of
acceleration. We describe an accelerometer that exploits the dispersive and
dissipative coupling of the motion of an optical whispering gallery mode (WGM)
resonator to a waveguide. A silica microsphere-cantilever is used as both the
optical cavity and inertial test-mass. Deflections of the cantilever in
response to acceleration alter the evanescent coupling between the microsphere
and the waveguide, in turn causing a measurable frequency shift and broadening
of the WGM resonance. The theory of this optomechanical response is outlined.
By extracting the dispersive and dissipative optomechanical rates from data we
find good agreement between our model and sensor response. A noise density of
4.5 g Hz with a bias instability of 31.8 g (g=9.81
ms) is measured, limited by classical noise larger than the test-mass
thermal motion. Closed-loop feedback is demonstrated to reduce the bias
instability and long term drift. Currently this sensor outperforms both
commercial accelerometers used for navigation and those in ballistocardiology
for monitoring blood flowing into the heart. Further optimization would enable
short-range gravitational force detection with operation beyond the lab for
terrestrial or space gradiometry.Comment: 8 pages, 9 figures. Minor changes: additional methodology for
calculating noise terms with recalculation of acceleration random walk and
rate ramp. Gradient guide-lines and arrows on Figure 7(a) corrected, no
change to dat
Astrophysical factor for the reaction from -matrix analysis and asymptotic normalization coefficient for . Is any fit acceptable?
The reaction provides a path from the CN
cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor
for this reaction is dominated by resonant capture through two strong
resonances at and 962 keV and direct capture to
the ground state. Recently, a new measurement of the astrophysical factor for
the reaction has been published [P. J.
LeBlanc {\it et al.}, Phys. Rev. {\bf C 82}, 055804 (2010)]. The analysis has
been done using the -matrix approach with unconstrained variation of all
parameters including the asymptotic normalization coefficient (ANC). The best
fit has been obtained for the square of the ANC fm,
which exceeds the previously measured value by a factor of . Here we
present a new -matrix analysis of the Notre Dame-LUNA data with the fixed
within the experimental uncertainties square of the ANC
fm. Rather than varying the ANC we add the contribution from a
background resonance that effectively takes into account contributions from
higher levels. Altogether we present 8 fits, five unconstrained and three
constrained. In all the fits the ANC is fixed at the previously determined
experimental value fm. For the unconstrained fit with
the boundary condition , where is the energy of the
second level, we get keVb and normalized , i.e. the result which is similar to [P. J. LeBlanc {\it et
al.}, Phys. Rev. {\bf C 82}, 055804 (2010)]. From all our fits we get the range
keVb which overlaps with the result of [P. J.
LeBlanc {\it et al.}, Phys. Rev. {\bf C 82}, 055804 (2010)]. We address also
physical interpretation of the fitting parameters.Comment: Submitted to PR
Glassy dynamics in granular compaction
Two models are presented to study the influence of slow dynamics on granular
compaction. It is found in both cases that high values of packing fraction are
achieved only by the slow relaxation of cooperative structures. Ongoing work to
study the full implications of these results is discussed.Comment: 12 pages, 9 figures; accepted in J. Phys: Condensed Matter,
proceedings of the Trieste workshop on 'Unifying concepts in glass physics
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Analysis of wheat SAGE tags reveals evidence for widespread antisense transcription
BACKGROUND: Serial Analysis of Gene Expression (SAGE) is a powerful tool for genome-wide transcription studies. Unlike microarrays, it has the ability to detect novel forms of RNA such as alternatively spliced and antisense transcripts, without the need for prior knowledge of their existence. One limitation of using SAGE on an organism with a complex genome and lacking detailed sequence information, such as the hexaploid bread wheat Triticum aestivum, is accurate annotation of the tags generated. Without accurate annotation it is impossible to fully understand the dynamic processes involved in such complex polyploid organisms. Hence we have developed and utilised novel procedures to characterise, in detail, SAGE tags generated from the whole grain transcriptome of hexaploid wheat. RESULTS: Examination of 71,930 Long SAGE tags generated from six libraries derived from two wheat genotypes grown under two different conditions suggested that SAGE is a reliable and reproducible technique for use in studying the hexaploid wheat transcriptome. However, our results also showed that in poorly annotated and/or poorly sequenced genomes, such as hexaploid wheat, considerably more information can be extracted from SAGE data by carrying out a systematic analysis of both perfect and "fuzzy" (partially matched) tags. This detailed analysis of the SAGE data shows first that while there is evidence of alternative polyadenylation this appears to occur exclusively within the 3' untranslated regions. Secondly, we found no strong evidence for widespread alternative splicing in the developing wheat grain transcriptome. However, analysis of our SAGE data shows that antisense transcripts are probably widespread within the transcriptome and appear to be derived from numerous locations within the genome. Examination of antisense transcripts showing sequence similarity to the Puroindoline a and Puroindoline b genes suggests that such antisense transcripts might have a role in the regulation of gene expression. CONCLUSION: Our results indicate that the detailed analysis of transcriptome data, such as SAGE tags, is essential to understand fully the factors that regulate gene expression and that such analysis of the wheat grain transcriptome reveals that antisense transcripts maybe widespread and hence probably play a significant role in the regulation of gene expression during grain development
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