10,944 research outputs found
Monterey Bay study
The multispectral scanner capabilities of LANDSAT 1 were tested over California's Monterey Bay area and portions of the San Joaquin Valley. Using both computer aided and image interpretive processing techniques, the LANDSAT 1 data were analyzed to determine their potential application in terms of land use and agriculture. Utilizing LANDSAT 1 data, analysts were able to provide the identifications and areal extent of the individual land use categories ranging from very general to highly specific levels (e.g., from agricultural lands to specific field crop types and even the different stages of growth). It is shown that the LANDSAT system is useful in the identification of major crop species and the delineation of numerous land use categories on a global basis and that repeated surveillance would permit the monitoring of changes in seasonal growth characteristics of crops as well as the assessment of various cultivation practices with a minimum of onsite observation. The LANDSAT system is demonstrated to be useful in the planning and development of resource programs on earth
Acoustooptic pulse-echo transducer system
A pulse-echo transducer system which uses an ultrasonic generating element and an optical detection technique is described. The transmitting transducer consists of a concentric ring electrode pattern deposited on a circular, X-cut quartz substrate with a circular hole in the center. The rings are independently pulsed with a sequence high voltage signals phased in such a way that the ultrasonic waves generated by the separate rings superimpose to produce a composite field which is focused at a controllable distance below the surface of the specimen. The amplitude of the field reflected from this focus position is determined by the local reflection coefficient of the medium at the effective focal point. By processing the signals received for a range of ultrasonic transducer array focal lengths, the system can be used to locate and size anomalies within solids and liquids. Applications in both nondestructive evaluation and biomedical scanning are suggested
On three-dimensional reconstruction of optically thin solar emission sources
Calculations are given for constructing the three dimensional distribution of optically thin EUV emission sources associated with solar active regions, from two dimensional observations (projections) recorded by the spectroheliograph on the OSO 7 satellite. The relation of the method to other image reconstruction methods is briefly discussed as well as the special requirements imposed in the solar case such as a knowledge of the true solar rotation function. A useful correlation criterion for establishing the physical validity of solutions is given
The results of an agricultural analysis of the ERTS-1 MSS data at the Johnson Space Center
The initial analysis of the ERTS-1 multispectral scanner (MSS) data at the Johnson Space Center (JSC), Houston, Texas is discussed. The primary data set utilized was the scene over Monterey Bay, California, on July 25, 1972, NASA ERTS ID No. 1002-18134. It was submitted to both computerized and image interpretative processing. An area in the San Joaquin Valley was submitted to an intensive evaluation of the ability of the data to (1) discriminate between crop types and (2) to provide a reasonably accurate area measurement of agricultural features of interest. The results indicate that the ERTS-1 MSS data is capable of providing the identifications and area extent of agricultural lands and field crop types
The Value of Regional Annual Nitrogen Needs Information for Wheat Producers in Oklahoma
Crop producers are increasingly interested in reducing nitrogen use without sacrificing yield. Technology is available for precise application at the sub-field level, but adoption has been sluggish. This paper estimates the relative profitability of a field level annual predictor of mid-season N requirements and a regional predictor of the same.nitrogen seeds, nitrogen use efficiency, precision agriculture, wheat, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
Magnetic field structure in single late-type giants: Beta Ceti in 2010 - 2012
The data were obtained using two spectropolarimeters - Narval at the Bernard
Lyot Telescope, Pic du Midi, France, and ESPaDOnS at CFHT, Hawaii. Thirty-eight
circularly-polarized spectra have been collected in the period June 2010 -
January 2012. The Least Square Deconvolution method was applied for extracting
high signal-to-noise ratio line profiles, from which we measure the
surface-averaged longitudinal magnetic field Bl. Chromospheric activity
indicators CaII K, H_alpha, CaII IR (854.2 nm) and radial velocity were
simultaneously measured and their variability was analysed together with the
behavior of Bl. The Zeeman Doppler Imaging (ZDI) inversion technique was
employed for reconstruction of the large-scale magnetic field and two magnetic
maps of Beta Ceti are presented for two periods (June 2010 - December 2010 and
June 2011 - January 2012). Bl remains of positive polarity for the whole
observational period. The behavior of the line activity indicators is in good
agreement with the Bl variations. The two ZDI maps show a mainly axisymmetric
and poloidal magnetic topology and a simple surface magnetic field
configuration dominated by a dipole. Little evolution is observed between the
two maps, in spite of a 1 yr interval between both subsets. We also use
state-of-the-art stellar evolution models to constrain the evolutionary status
of Beta Ceti. We derive a mass of 3.5 M_sun and propose that this star is
already in the central-helium burning phase. Taking into account all our
results and the evolutionary status of the star, we suggest that dynamo action
alone may not be eficient enough to account for the high magnetic activity of
Beta Ceti. As an alternate option, we propose that it may be an Ap star
descendant presently undergoing central helium-burning and still exhibiting a
remnant of the Ap star magnetic field.Comment: 10 pages; 5 figures; 3 table
Sediment Management for Southern California Mountians, Coastal Plains and Shoreline. Part D: Special Inland Studies
In southern California the natural environmental system involves the continual relocation of sedimentary materials. Particles are eroded from inland areas where there is sufficient relief and, precipitation. Then, with reductions in hydraulic gradient along the stream course and at the shoreline, the velocity of surface runoff is reduced and there is deposition. Generally, coarse sand, gravel and larger particles are deposited near the base of the eroding surfaces (mountains and hills) and the finer sediments are deposited on floodplains, in bays or lagoons, and at the shoreline as delta deposits. Very fine silt and clay particles, which make up a significant part of the eroded material, are carried offshore where they eventually deposit in deeper areas. Sand deposited at the shoreline is gradually moved along the coast by waves and currents, and provides nourishment for local beaches. However, eventually much of this littoral material is also lost to offshore areas. Human developments in the coastal region have substantially altered the natural sedimentary processes, through changes in land use, the harvesting of natural resources (logging, grazing, and sand and gravel mining); the construction and operation of water conservation facilities and flood control structures; and coastal developments. In almost all cases these developments have grown out of recognized needs and have well served their primary purpose. At the time possible deleterious effects on the local or regional sediment balance were generally unforeseen or were felt to be of secondary importance. In 1975 a large-scale study of inland and coastal sedimentation processes in southern California was initiated by the Environmental Quality Laboratory at the California Institute of Technology and the Center for Coastal Studies at Scripps Institution of Oceanography. This volume is one of a series of reports from this study. Using existing data bases, this series attempts to define quantitatively inland and coastal sedimentation processes and identify the effects man has had on these processes. To resolve some issues related to long-term sediment management, additional research and data will be needed. In the series there are four Caltech reports that provide supporting studies for the summary report (EQL Report No. 17). These reports include: EQL Report 17-A Regional Geological History EQL Report 17-B Inland Sediment Movements by Natural Processes EQL Report 17-C Coastal Sediment Delivery by Major Rivers in Southern California EQL Report 17-D -- Special Inland Studies Additional supporting reports on coastal studies (shoreline sedimentation processes, control structures, dredging, etc.) are being published by the Center for Coastal Studies at Scripps Institution of Oceanography, La Jolla, California
ProSAT2—Protein Structure Annotation Server
ProSAT2 is a server to facilitate interactive visualization of sequence-based, residue-specific annotations mapped onto 3D protein structures. As the successor of ProSAT (Protein Structure Annotation Tool), it includes its features for visualizing SwissProt and PROSITE functional annotations. Currently, the ProSAT2 server can perform automated mapping of information on variants and mutations from the UniProt KnowledgeBase and the BRENDA enzyme information system onto protein structures. It also accepts and maps user-prepared annotations. By means of an annotation selector, the user can interactively select and group residue-based information according to criteria such as whether a mutation affects enzyme activity. The visualization of the protein structures is based on the WebMol Java molecular viewer and permits simultaneous highlighting of annotated residues and viewing of the corresponding descriptive texts. ProSAT2 is available at
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