91 research outputs found

    Florida’s Shad and River Herrings (Alosa species): a review of Population and Fishery Characteristics

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    Of the six shad and river herring species (Clupeidae: Alosa species) found in North America, five occur in Florida (Figure 1), more than in any other state in the U.S. These species, with one possible exception, are anadromous (i.e., they move from salt water to fresh water to spawn). On Florida’s Atlantic coast, there are three species: American shad (Alosa sapidissima), hickory shad (A. mediocris), and blueback herring (A. aestivalis). Two species are present on Florida’s gulf coast: Alabama shad (A. alabamae) and skipjack herring (A. chrysochloris).The Atlantic species range northward from Florida to as far as Canada, and the gulf species range westward to Louisiana. This document summarizes information about Florida’s populations of Alosa species and discusses the status and trends of those populations. (26pp.

    The 100th Anniversary of the Fall of Nakhla: The Subdivision of BM1913,25

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    This year marks the 100th anniversary of the fall of Nakhla, a cumulate clinopyroxenite of martian origin that fell near Alexandria, Egypt in 1911. Multiple fragments of the meteorite were seen to fall over an area of 4.5 km in diameter. Approximately 40 stones were recovered with a combined weight of about 10 kg. Most of the larger specimens found their way to museums and meteorite collections in Cairo, Paris, Berlin, and the Smithsonian, to name a few. In 1998, the British Museum sent a 641g (BM1913,25), fully fusion crusted stone of Nakhla to the Johnson Space Center (JSC) for processing in the Antarctic Meteorite Lab in order to allocate samples to the scientific community. The stone was split in half in a dry nitrogen glove box. One half of the stone was sent back to the museum and the other half (346g) was used for sample allocations. From 1998-2001, 37 scientists requested 65 separate samples of Nakhla, including 2 thin sections This set of allocations was especially important in that all of the sample splits are from the same piece of Nakhla and it had a known history since it was acquired by the museum in 1913. With the multiple fragments of Nakhla, it is not known from what pieces the main bulk of research has been done, what variation may exist between all the pieces and to what contaminants the fragments may have been exposed, (i.e. water, solvents or cutting fluids, etc.). All of the allocations prepared at JSC were processed in a nitrogen cabinet using only stainless steel, aluminum, and Teflon tools and containers to reduce the chance of introducing any new contaminants. The focused effort to subdivide and distribute samples of Nakhla to the meteorite community resulted in enhanced under-standing of Nakhla and nakhlites in general: organic geochemistry, weathering, sulfur isotopes, radiometric age, and magmatic history. There are 13 Nakhlites that have been recovered to date: Nakhla, Layfayette, Governador Valdares, three from NW Africa, three from Yamato and four from Miller Range regions in Antarctica. The Yamato Nakhlites are paired as are the Miller Range samples

    The Miller Range Nakhlites: A Summary of the Curatorial Subdivision of the Main Mass in Light of Newly Found Paired Masses

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    The 2003-2004 ANSMET team re-covered a 715.2 g nakhlite from the Miller Range (MIL) region of the Transantarctic Mountains (MIL 03346). This was the first nakhlite for the US Antarctic meteorite program, and after the announcement in 2004 [1], JSC received over 50 requests for this sample for the Fall 2004 Meteorite Working Group meeting. Since then it has been subdivided into >200 splits, and distributed to approx.70 scientists around the world for study. The 2009-2010 ANSMET team recovered three additional masses of this nakhlite [2], making the total amount of mass 1.871 kg (Table 1). Given that the original find (MIL 03346) has been heavily studied and these new masses are available, we will present a comprehensive overview of the subdivision of the original mass as well as the scientific findings to date

    Handling Heavenly Jewels - 35 Years of Antarctic Meteorite Processing at Johnson Space Center

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    The ANSMET program began in 1976, and since that time more than 18,000 meteorites have been processed in the Meteorite Processing Lab at Johnson Space Center in Houston, TX[1]. The meteorites are collected and returned to JSC on a freezer truck and remain frozen until they are initially processed. Initial Processing of Meteorites: Initial processing involves drying the meteorites in a nitrogen glove box for 24 to 48 hours, photographing, measuring, weighing and writing a description of the interior and exterior. The meteorite is broken and a representative sample is sent to the Smithsonian Institution for classification. Newsletter & Requests: Once initial processing has been complete and the meteorites have been classified, the information is published in the Antarctic Meteorite Newsletter[2,3]. The newsletter is published twice yearly and is sent electronically to researchers around the world and is also available on line. Researchers are asked to fill out a request form and submit it to the Meteorite Working Group secretary. All sample requests will be reviewed by either the meteorite curator or the Meteorite Working Group de-pending on the type of meteorite and the research being conducted. Processing for Sample Requests: In the meteorite processing lab, meteorite samples are prepared several different ways. Most samples are prepared as chips obtained by use of stainless steel chisels in a chipping bowl or rock splitter. In special situations where a researcher needs a slab the meteorite samples can be bandsawed in a dry nitrogen glove box with a diamond blade, no liquids are ever introduced into the cabinet. The last type of sample preparation is thin/thick sections. The meteorite thin section lab at JSC can prepare standard 30-micron thin sections, thick sections of variable thickness (100 to 200 microns), or demountable sections using superglue. Information for researchers: It is important that re-searchers fill the sample request form completely, in order to make sure the meteorite is processed correctly[4]. Re-searchers should list any special requirements on the form, i.e. packaging of samples (poly vs. stainless), thick sections and thickness needed, superglue needed, interior chips, exterior chips, fusion crust, contamination issues, all concerns should be listed so processing can be done accurately and any concerns the researcher has can be addressed be-fore the meteorites are broken

    Processing of Antarctic Meteorites at NASA/Johnson Space Center

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    Since the beginning of the Antarctic Search for Meteorites (ANSMET) program in 1976, over 18,000 meteorites have been processed in the Meteorite Processing Lab at Johnson Space Center in Houston, TX. The first step is to renumber the meteorites from field tag number to generic number and log all the information into the meteorite database. Initial processing involves drying the meteorites in a nitrogen glove box for 24 to 48 hours, photographing, measuring, weighing and writing an exterior description. Next step is to break the meteorite and obtain a good representative sample that will be sent to the Smithsonian institution for classification. Once all the processing is done and the meteorites have been classified, the information is published in the Antarctic meteorite newsletter. The newsletter is published twice yearly and is sent electronically to researchers around the world and is also available on line. Researchers are asked to fill out a request form. The bulk of this paper relates to the researcher's request for meteorite samples

    Hydrodynamic Investigation of the the Take-Off Characteristics of a 1/10-Scale Dynamic Model of the Convair XF2Y-1 Airplane

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    An investigation was made of the take-off characteristics of a 1/10-scale dynamic model of the Convair XF2Y-1 airplane. This airplane is a water-based, jet-propelled, delta-wing fighter incorporating a hydro-ski landing gear. Tests were made with the original configuration, with the beaching wheels removed, and with the wheels installed and fairings added in front of the wheels. Each configuration was tested at weight and balance conditions simulating 17,000 pounds gross weight with the moment due t o 7,600 pounds of thrust, 17,300 pounds gross weight with a 9,500-pound thrust condition, and 23,000 pounds gross weight with a 9,300-pound thrust condition. Constant-speed runs were made at various elevon settings and vertical ski-strut positions; and trim, rise, and resistance were measured. Accelerated runs were made with controlled elevons and scale shock struts which could be extended as desired, and the longitudinal stability and spray characteristics were observed and photographed

    Skiers and skiing at Snowbird, Utah [024]

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    Photo shows a skier at the Snowbird Ski Resort in Little Cottonwood Canyon, Uta

    The Constitutional Law of Jamaica. By Lloyd G. Barnett, b.a.

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    Filmmakers on Filmmaking Volume 2

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