9,234 research outputs found

    Diet of oceanic loggerhead sea turtles (Caretta caretta) in the central North Pacific

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    Diet analysis of 52 loggerhead sea turtles (Caretta caretta) collected as bycatch from 1990 to 1992 in the high-seas driftnet fishery operating between lat. 29.5°N and 43°N and between long. 150°E and 154°W demonstrated that these turtles fed predominately at the surface; few deeper water prey items were present in their stomachs. The turtles ranged in size from 13.5 to 74.0 cm curved carapace length. Whole turtles (n =10) and excised stomachs (n= 42) were frozen and transported to a laboratory for analysis of major faunal components. Neustonic species accounted for four of the five most common prey taxa. The most common prey items were Janthina spp. (Gastropoda); Carinaria cithara Benson 1835 (Heteropoda); a chondrophore, Velella velella (Hydrodia); Lepas spp. (Cirripedia), Planes spp. (Decapoda: Grapsidae), and pyrosomas (Pyrosoma spp.)

    Sexual decision making in the absence of choice: The African American female dating experience.

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    Although links between low mate availability and increased HIV and STI risk for African American women have been documented in the literature, we know little about the impact of limited mate choices on the quality of relationships between Black men and women and how these relationship dynamics impact risk for young Black women. We conducted a qualitative study with African American female young adults (N=12) to explore the perceived impact of structural forces on African American female young adults’ dating and sexual behavior. Participants reported (1) perceptions of Black men as untrustworthy and manipulative, (2) the limited and often negative roles for Black men in the larger Black community, and (3) heterosexual relationships in the Black community as increasingly influenced by economics and commerce. Recommendations for HIV prevention interventions that include micro and macro level approaches are discussed

    Trace Element Composition of Stream Sediments an Integrating Factor for Water Quality

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    Bottom sediments, suspended sediments, and water were sampled along 130 miles of the Buffalo River in northern Arkansas. The water and acid extracts of the suspended sediments and the minus 95 mesh fraction of the bottom sediments were analyzed by atomic absorption spectrometry. All samples were analyzed for Na, K, Mg, Ca, Zn, Cd, Cu, Pb, Fe, Co, Cr, Ni, and Mn. Selected bottom samples also were analyzed by As, Hg, and Zr. Zr was determined by x-ray fluorescence. Li and Sr were determined for selected water and suspended sediment samples. There is a general decrease downstream in Fe, Cu, Cr, Ni, Mn, Pb, K, and Na in the bottom sediments as the drainage area increases in carbonate rock and decreases in shale. The elements Mg, Ca, Zn, and Cd increase in bottom sediments downstream. The values for these elements in the water, especially the major elements, also correspond closely with the geology of the region. Tributaries are sites of abrupt rise and fall of metal values, within a few miles, from background to anomalously high values to background, especially tributaries draining Zn and Pb mineralized areas. The bottom sediments are mainly quartz and chert grains. These grains apparently are coated with hydrous iron oxide which acts as a sorbent for many of the elements and is a dominant transport mechanism for acid extractable Co, Cr, Ni, Cu, Mn, and K. Other acid extractable metals, particularly Mg, Ca, Zn, Cd, and Pb, are mostly in clastic grains. Graphic representation of the Langmuir equation for Mn is consistent with adsorption of Mn by iron in both bottom sediments and suspended sediments. On the basis of the volume of water collected, all the elements except Fe are more concentrated in the water than in the suspended sediments. Fe concentration of the suspended sediments increases with increasing flow because the suspended load is increased. The Mn/Fe ratio of the suspended sediments is approximately equal to or greater than that of the bottom sediments. The Mn/Fe ratio of suspended sediments relative to that of the bottom sediments increases downstream, possibly because of an autocatalytic effect of Mn precipitation. The relationship between sediment and water concentrations is not clear from the data because of the restricted concentration ranges for some elements in the suspended sediment and water. The sediment from the Buffalo River can be used to estimate grossly the concentration of elements in the water

    The Reaction of Potassium Amide in Liquid Ammonia with Diarylbromethenes

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    The behavior of certain diarylchloroethenes with potassium amide in liquid ammonia has been reported previously. A rapid reaction occurs and the ethenes are changed with the loss of hydrochloric acid to tolanes. Thus 1, 1-di-p-tolyl-2-chloroethene forms p. p\u27-dimethyltolane. A series of such para substituted compounds was studied and as anticipated only symmetrical tolanes were obtained

    Magnification Ratio of the Fluctuating Light in Gravitational Lens 0957+561

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    Radio observations establish the B/A magnification ratio of gravitational lens 0957+561 at about 0.75. Yet, for more than 15 years, the optical magnfication ratio has been between 0.9 and 1.12. The accepted explanation is microlensing of the optical source. However, this explanation is mildly discordant with (i) the relative constancy of the optical ratio, and (ii) recent data indicating possible non-achromaticity in the ratio. To study these issues, we develop a statistical formalism for separately measuring, in a unified manner, the magnification ratio of the fluctuating and constant parts of the light curve. Applying the formalism to the published data of Kundi\'c et al. (1997), we find that the magnification ratios of fluctuating parts in both the g and r colors agrees with the magnification ratio of the constant part in g-band, and tends to disagree with the r-band value. One explanation could be about 0.1 mag of consistently unsubtracted r light from the lensing galaxy G1, which seems unlikely. Another could be that 0957+561 is approaching a caustic in the microlensing pattern.Comment: 12 pages including 1 PostScript figur

    Research on the human factor in the transfer of technology

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    The Magellanic System: What have we learnt from FUSE?

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    I review some of the findings on the Magellanic System produced by the Far Ultraviolet Spectroscopic Explorer (FUSE) during and after its eight years of service. The Magellanic System with its high-velocity complexes provides a nearby laboratory that can be used to characterize phenomena that involve interaction between galaxies, infall and outflow of gas and metals in galaxies. These processes are crucial for understanding the evolution of galaxies and the intergalactic medium. Among the FUSE successes I highlight are the coronal gas about the LMC and SMC, and beyond in the Stream, the outflows from these galaxies, the discovery of molecules in the diffuse gas of the Stream and the Bridge, an extremely sub-solar and sub-SMC metallicity of the Bridge, and a high-velocity complex between the Milky Way and the Clouds.Comment: A contributed paper to the FUSE Annapolis Conference "Future Directions in Ultraviolet Spectroscopy.", 5 pages. To appear as an AIP Conference Proceedin
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