6,973 research outputs found

    Genetic diversity in wild stocks of the giant freshwater prawn (Macrobrachium rosenbergii): implications for aquaculture and conservation

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    The giant freshwater prawn (Macrobrachium rosenbergii) is cultured widely around the world but little is known about the levels and patterns of genetic diversity in either wild or cultured stocks. Studies have suggested that genetic diversity may be relatively low in some cultured stocks due to the history of how they were founded and subsequent exposure to repeated population bottlenecks in hatcheries. In contrast, wild stocks have an extensive distribution that extends from Southern Asia across Southeast (SE) Asia to the Pacific region. Therefore, wild stocks could be an important resource for genetic improvement of culture stocks in the future. Understanding the extent and patterns of genetic diversity in wild giant freshwater prawn stocks will assist decisions about the direction future breeding programs may take. Wild stock genetic diversity was examined using a 472 base-pair segment of the 16S rRNA gene in 18 wild populations collected from across the natural range of the species. Two major clades ("eastern" and "western") were identifi ed either side of Huxley’s line, with a minimum divergence of 6.2 per cent, which implies separation since the Miocene period (5-10 MYA). While divergence estimates within major clades was small (maximum 0.9 per cent), evidence was also found for population structuring at a lower spatial scale. This will be examined more intensively with a faster evolving mtDNA gene in the future

    Genetic diversity in wild stocks of the giant freshwater prawn (Macrobrachium rosenbergii): implications for aquaculture and conservation

    Get PDF
    The giant freshwater prawn (Macrobrachium rosenbergii) is cultured widely around the world but little is known about the levels and patterns of genetic diversity in either wild or cultured stocks. Studies have suggested that genetic diversity may be relatively low in some cultured stocks due to the history of how they were founded and subsequent exposure to repeated population bottlenecks in hatcheries. In contrast, wild stocks have an extensive distribution that extends from Southern Asia across Southeast (SE) Asia to the Pacific region. Therefore, wild stocks could be an important resource for genetic improvement of culture stocks in the future. Understanding the extent and patterns of genetic diversity in wild giant freshwater prawn stocks will assist decisions about the direction future breeding programs may take. Wild stock genetic diversity was examined using a 472 base-pair segment of the 16S rRNA gene in 18 wild populations collected from across the natural range of the species. Two major clades ("eastern" and "western") were identifi ed either side of Huxley’s line, with a minimum divergence of 6.2 per cent, which implies separation since the Miocene period (5-10 MYA). While divergence estimates within major clades was small (maximum 0.9 per cent), evidence was also found for population structuring at a lower spatial scale. This will be examined more intensively with a faster evolving mtDNA gene in the future.Genetic diversity, Stocks, Nature conservation Macrobrachium rosenbergii

    Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation

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    Ultrasound has been examined previously as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose response to ultrasound transmission measurements. In this current work we extend previous work to measure the broadband ultrasound attenuation (BUA) response of irradiated PAGAT gel dosimeters, using a novel ultrasound computed tomography system

    Clustering of the Diffuse Infrared Light from the COBE DIRBE maps. I. C(0)C(0) and limits on the near-IR background

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    This paper is devoted to studying the CIB through its correlation properties. We studied the limits on CIB anisotropy in the near IR (1.25, 2.2, and 3.5 \um, or J,  K,  LJ,\;K,\;L) bands at a scale of 0.7\deg\ using the COBE\footnote{ The National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) is responsible for the design, development, and operation of the {\it COBE}. Scientific guidance is provided by the {\it COBE} Science Working Group. GSFC is also responsible for the development of the analysis software and for the production of the mission data sets.} Diffuse Infrared Background Experiment (DIRBE) data. In single bands we obtain the upper limits on the zero-lag correlation signal C(0)=(νδIν)2<3.6×1016,  5.1×1017,  5.7×1018C(0)= \langle(\nu \delta I_\nu)^2\rangle < 3.6 \times 10^{-16},\; 5.1 \times 10^{-17},\; 5.7 \times 10^{-18} \w2m4sr2 for the J,K,LJ,K,L bands respectively. The DIRBE data exhibit a clear color between the various bands with a small dispersion. On the other hand most of the CIB is expected to come from redshifted galaxies and thus should have different color properties. We use this observation to develop a `color subtraction' method of linear combinations of maps at two different bands. This method is expected to suppress the dominant fluctuations from foreground stars and nearby galaxies, while not reducing (or perhaps even amplifying) the extragalactic contribution to C(0)C(0). Applying this technique gives significantly lower and more isotropic limits.Comment: 44 pages postcript; includes 5 tables, 14 figures. Astrophysical Journal, in pres

    Clustering of DIRBE Light and IR Background

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    We outline a new method for estimating the cosmic infrared background using the spatial and spectral correlation properties of infrared maps. The cosmic infrared background from galaxies should have a minimum fluctuation of the order of 10\% on angular scales of the order of 1\deg. We show that a linear combination of maps at different wavelengths can greatly reduce the fluctuations produced by foreground stars, while not eliminating the fluctuations of the background from high redshift galaxies. The method is potentially very powerful, especially at wavelengths where the foreground is bright but smooth.Comment: 7 pages postcript, talk at "Unveiling the cosmic infrared background" workshop, College Park, M

    Automotive Stirling Engine Development Program

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    The background and history of the Stirling engine, the technology, materials, components, controls, and systems, and a technical assessment of automotive stirling engines are presented

    The Magic Circle: Inclusion of Adopted Children in Testamentary Class Gifts

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    In two recent Texas appellate court decisions, the courts were faced with the problem of deciding whether a testator meant to include, or at least did not intend to exclude, adopted children in a testamentary class gift. Courts across the United States have struggled with this issue in recent years, and an increasing number are holding that gifts to children, issue, or lineal descendants do not necessarily exclude adopted children. However, in both Texas cases, the courts held that the adopted children could not take as members of the class. This result is contrary to both the modem trend of court decisions nationwide and the prevailing public policy regarding adoption, particularly as exemplified by state adoption statutes. Like many states, Texas has enacted statutory provisions, in both the Family Code and Probate Code, indicating that adopted children should be treated as natural-born children. Although testators may make any conveyances they wish, and exclude any person they wish, it appears to be the public policy of this state to start with a presumption in favor of inclusion of adopted children in testamentary class gifts

    How and Why Do Lawyers Misbehave? Lawyers, Discipline, and Collegial Control

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    Published as Chapter 6 in The Paradox of Professionalism: Lawyers and the Possibility of Justice, Scott L. Cummings, ed. A fundamental principle of professional labor is that the members of a specialized occupation, as professionals, enjoy autonomy. In sociologist Elliot Freidson\u27s words, professionals “control their own work.” The practitioners themselves decide what constitutes acceptable or appropriate behavior. Professions establish rules and systems of self-regulation to teach and enforce the expected standards of conduct on their members. One way, then, to assess legal professionalism is to ask how well lawyers regulate themselves. The extensive literature on lawyer regulation paints a negative picture. The Watergate scandal of the early 1970s brought renewed scrutiny to the legal profession. Although a variety of changes have occurred since then to improve lawyer regulation, numerous problems remain. Law schools now require students to take legal ethics, but such courses generally lack stature and respect. Bar discipline was reorganized in the 1970s to transfer some control from bar associations to agencies of state supreme courts. State discipline agencies in turn have increased their investigation of grievances filed against lawyers. But the vast majority of grievances continue to be dismissed. Much professional discipline is private (such as a warning letter, reprimand, or confidential diversion program), which undermines public trust and confidence in the system. Further, even the most common forms of public sanctions on lawyers (public censure, suspension, or disbarment) are specific to that state, and nothing prevents a sanctioned attorney from seeking bar admission in another state (although they would be required to disclose any prior sanctions).https://digitalcommons.law.buffalo.edu/book_sections/1300/thumbnail.jp
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