2,397 research outputs found
Radar backscattering as a means for measuring ocean surface parameters using S193 altimetry and S190B photography
There are no author-identified significant results in this report
Radar backscattering as a means for measuring ocean surface parameters using S193 altimetry and S190B photography
There are no author-identified significant results in this report
Remote lightning monitor system
An apparatus for monitoring, analyzing and accurately determining the value of peak current, the peak rate of change in current with respect to time and the rise time of the electrical currents generated in an electrical conductive mast that is located in the vicinity where lightning is to be monitored is described. The apparatus includes an electrical coil for sensing the change in current flowing through the mast and generating a voltage responsive. An on-site recorder and a recorder control system records the voltages produced responsive to lightning strikes and converts the voltage to digital signals for being transmitted back to the remote command station responsive to command signals. The recorder and the recorder control system are carried within an RFI proof environmental housing into which the command signals are fed by means of a fiber optic cable so as to minimize electrical interference
An Analytical Investigation of Acquisition Techniques and System Integration Studies for a Radar Aircraft Guidance Research Facility
Boresight camera records for angular tracking accuracy of aircraf
Radar backscattering as a means for measuring ocean surface parameters using S193 altimetry and S190B photography
There are no author-identified significant results in this report
An investigation of errors and data processing techniques for an RF multilateration system
The development of an RF Multilateration system to provide accurate position and velocity measurements during the approach and landing phase of Vertical Takeoff Aircraft operation is discussed. The system uses an angle-modulated ranging signal to provide both range and range rate measurements between an aircraft transponder and multiple ground stations. Range and range rate measurements are converted to coordinate measurements and the coordinate and coordinate rate information is transmitted by an integral data link to the aircraft. Data processing techniques are analyzed to show advantages and disadvantages. Error analyses are provided to permit a comparison of the various techniques
Archaeological Testing of the Burleson Homestead at 41HY37 Hays County, Texas
At the request of Southwest Texas State University (now Texas State University-San Marcos), the Center for Archaeological Studies (CAS) conducted an archaeological excavation of the historic Burleson Homestead (41HY37). The excavation was conducted in June and July of 2000 under Texas Antiquities Committee Permit No. 2406. Artifacts collected during the project were processed and curated at CAS. In addition, CAS conducted archival research on structures located within the project boundaries. Upon completion of the excavation and archival research, a great deal has been learned concerning the Burleson ownership and use of the San Marcos Springs. Unfortunately, little intact evidence survives. CAS determined that the original cabin had been completely dismantled and a replica cabin was assembled nearby, but not on the original foundation . Most of the deposits on the ridge top have been disturbed and most of the recorded features relate to the construction of the replica cabin in the 1960s. The one early feature that does survive, Feature 4, should be preserved and used to provide a more accurate and full understanding of the locale when Edward Burleson settled the site and helped establish the community of San Marcos. CAS therefore recommends that no further archaeological investigations are necessary and that the site should be used to further the public education of the early history of the San Marcos Springs and the City of San Marcos
Lymphotoxins and cytomegalovirus cooperatively induce interferon-beta, establishing host-virus détente
Tumor necrosis factor (TNF)-related cytokines regulate cell death and survival and provide strong selective pressures for viruses, such as cytomegalovirus (CMV), to evolve counterstrategies in order to persist in immune-competent hosts. Signaling by the lymphotoxin (LT)-β receptor or TNF receptor-1, but not Fas or TRAIL receptors, inhibits the cytopathicity and replication of human CMV by a nonapoptotic, reversible process that requires nuclear factor κB (NF-κB)-dependent induction of interferon-β (IFN-β). Efficient induction of IFN-β requires virus infection and LT signaling, demonstrating the need for both host and viral factors in the curtailment of viral replication without cellular elimination. LTα-deficient mice and LTβR-Fc transgenic mice were profoundly susceptible to murine CMV infection. Together, these results reveal an essential and conserved role for LTs in establishing host defense to CMV
Prehistoric Archeology and Paleoenvironments in Hidalgo and Willacy Counties, South Texas: Results of the Phase II Test Excavations
In May 1989 through July 1989, archeological and geomorphological investigations were conducted at five prehistoric archeological sites impacted by drainage ditch construction in Hidalgo and Willacy counties. These investigations were sponsored by Hidalgo County Drainage District No. I and Willacy County Drainage District No. I as part of a continuing program of cultural resources studies along the drainage ditch construction right-of-way. One site, 41WYI40, is situated on a low rise adjacent to a main channel of the ditch and lacks sufficient Holocene sediments to contain archeological materials in good context. However, a tortoise, cf. Gopherus hexagollarus, was recovered, and the inorganic fraction was assayed by radiocarbon to 9360 ± 415 B.P. If correct, this date indicates that these now-extinct tortoises could have been coeval with Paleoindian occupations in South Texas. The other four sites are in or on the edges of small deflationary basins. Based on the radiocarbon chronology obtained from these sites, soils formed on many of the deflationary basins during the late Pleistocene. Between ca. 12,000 B.P. and 5000 B.P., these soils were removed by wind erosion, and in the last 5,000 years, a modem soil formed. At all sites, this modem soil has been disturbed by historic farming, land clearing, and ditch construction. The prehistoric archeological remains at 41HGI28, 41WY1l2, 41WY1l3, and 41WYl34 are sparse, reflecting a continuing record of nonintensive use by mobile hunter-gatherers. In order to assess the National Register eligibility of individual sites, three models of hunter-gatherer resource and territorial exploitation patterns were developed and a preliminary test of these models was conducted with the regional archeological data base. The first model assumes unrestricted access to all major resource areas in the region; the second model assumes that prehistoric territories focused on resources along the Rio Grande floodplain; and Ole third model assumes that hunter-gatherer territories were organized in response to coastal resources. The results of the test were inconclusive, but important exploitation patterns were recognized and invalid assumptions of the models identified. In light of the recovered materials from the sites. the analysis of the regional data base, and the assessment of the models, none of the five sites reported here are judged eligible for listing on the National Register of Historic Places, and no further work at these sites is recommended
Prehistoric Archeology and Paleoenvironments in Hidalgo and Willacy Counties, South Texas: Results of the Phase II Test Excavations
In May 1989 through July 1989, archeological and geomorphological investigations were conducted at five prehistoric archeological sites impacted by drainage ditch construction in Hidalgo and Willacy counties. These investigations were sponsored by Hidalgo County Drainage District No. I and Willacy County Drainage District No. I as part of a continuing program of cultural resources studies along the drainage ditch construction right-of-way. One site, 41WYI40, is situated on a low rise adjacent to a main channel of the ditch and lacks sufficient Holocene sediments to contain archeological materials in good context. However, a tortoise, cf. Gopherus hexagollarus, was recovered, and the inorganic fraction was assayed by radiocarbon to 9360 ± 415 B.P. If correct, this date indicates that these now-extinct tortoises could have been coeval with Paleoindian occupations in South Texas. The other four sites are in or on the edges of small deflationary basins. Based on the radiocarbon chronology obtained from these sites, soils formed on many of the deflationary basins during the late Pleistocene. Between ca. 12,000 B.P. and 5000 B.P., these soils were removed by wind erosion, and in the last 5,000 years, a modem soil formed. At all sites, this modem soil has been disturbed by historic farming, land clearing, and ditch construction. The prehistoric archeological remains at 41HGI28, 41WY1l2, 41WY1l3, and 41WYl34 are sparse, reflecting a continuing record of nonintensive use by mobile hunter-gatherers. In order to assess the National Register eligibility of individual sites, three models of hunter-gatherer resource and territorial exploitation patterns were developed and a preliminary test of these models was conducted with the regional archeological data base. The first model assumes unrestricted access to all major resource areas in the region; the second model assumes that prehistoric territories focused on resources along the Rio Grande floodplain; and Ole third model assumes that hunter-gatherer territories were organized in response to coastal resources. The results of the test were inconclusive, but important exploitation patterns were recognized and invalid assumptions of the models identified. In light of the recovered materials from the sites. the analysis of the regional data base, and the assessment of the models, none of the five sites reported here are judged eligible for listing on the National Register of Historic Places, and no further work at these sites is recommended
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