8,971 research outputs found

    Bioassessment of the West Fork of the White River, Northwest Arkansas

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    The West Fork-White River has been and continues to be an important water resource for northwest Arkansas. It is used recreationally for fishing and swimming, agriculturally as a source of water for livestock and irrigation of crops, it is mined for gravel, used as a receiving stream for municipal wastewater effluent, and contributes to Beaver Lake which provides water for treatment and distribution to most of northwest Arkansas. While these uses have benefited a large segment of the Arkansas population, they have also contributed to the decline in environmental quality of the river. To facilitate the development of appropriate management protocols and assess restoration potential, we provided a biological assessment of the West ForkWhite River to complement studies of its physical and chemical properties. This holistic evaluation can be used presently, and to track changes in the environmental quality of the river in the future

    Distribution of Fish Within Headwater Riffles of the Illinois River System, Washington County, Arkansas

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    Quantitative sampling of fish was performed in five headwater riffles of the Illinois River System, Washington County, Arkansas during low flow conditions. This study revealed differing fish species composition, biomass and feeding guild segregation between head and tail riffle reaches in 1st through 3rd order. Thirty species representing 10 families were identified. Of this number, darters (Percidae), sculpins (Cottidae), madtoms (Ictaluridae), and central stonerollers (Campostoma anomalum) (Cyprinidae) comprised 67 to 98 percent of riffle head populations. Fish biomass was greater for riffle head areas (0.58-6.6/0.28-2.0 g/m2 ) within sectivores and herbivores dominating. Total fish numbers decreased from riffleheads to tails, while number of species increased. Dominant fish groups in tail areas were minnows (Cyprinidae), darters (Percidae), and sunfishes (Centrarchidae). Feeding guild fish groups in tail areas were predominately insectivore and insectivore-piscivore. Stomach analysis of Cottus carolinae, the dominant headwater riffle predator, indicated selective feeding of macrobenthic invertebrates and fish based on size class. Abundance of herbivore and insectivore fishes in riffles, particularly head reaches, suggests a correlation with positive rheotaxic behavior, microhabitat preference or abundance of macrobenthic invertebrate populations

    Computer program for Bessel and Hankel functions

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    A set of FORTRAN subroutines for calculating Bessel and Hankel functions is presented. The routines calculate Bessel and Hankel functions of the first and second kinds, as well as their derivatives, for wide ranges of integer order and real or complex argument in single or double precision. Depending on the order and argument, one of three evaluation methods is used: the power series definition, an Airy function expansion, or an asymptotic expansion. Routines to calculate Airy functions and their derivatives are also included

    Linear oscillations of a compressible hemispherical bubble on a solid substrate

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    The linear natural and forced oscillations of a hemispherical bubble on a solid substrate are under theoretical consideration. The contact line dynamics is taken into account with the Hocking condition, which eventually leads to interaction of the shape and volume oscillations. Resonant phenomena, mostly pronounced for the bubble with the fixed contact line or with the fixed contact angle, are found out. The limiting case of weakly compressible bubble is studied. The general criterion identifying whether the compressibility of a bubble can be neglected is obtained.Comment: new slightly extended version with some minor changes, added journal reference and DOI information; 12 pages, 8 figures, published in Physics of Fluid

    Nationality, Citizenship and Domicil in the Laws of Nigeria.

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    This thesis deals with two topics of Nigerian Law: (1) the Nationality and Citizenship Laws and (2) the Law of Domicil. The breakdown of the "common code" of British nationality heralded a new phase in the law of nationality and citizenship in the Commonwealth, and the evolution of its members into international relationships led to the enactment of divergent laws in States which previously shared a common nationality code. The emergence of Nigeria as a new independent power enabled the enactment of the first citizenship law. The Introductory Part deals briefly with the historical and constitutional background of Nigeria and a general treatment of the concepts of nationality and citizenship. Part 2 outlines the British Nationality Laws operating in Nigeria prior to October 1, 1960. Part 3 is a comprehensive analysis of the legal provisions for Nigerian citizenship contained in the Constitution, Acts of Parliament and Legal Notices. "Nigerian Nationality" and the concept of nationality in customary law are also considered. The final chapter on Citizenship and Non-Citizenship attempts to analyse the differences in the local law between the possession and non-possession of local citizenship. Part k deals with the second topic. Chapter 9 contrasts domicil with nationality and concludes with an analysis of the content of the law of domicil. Chapter 10 deals with the introduction into Nigeria of the concept of domicil and the scope of its operation, the effect of the federal legal structure on its application, proposals for the reform of the concept in England with a closing reconsideration of it

    Aquatic Macrophytes of Two Small Northwest Arkansas Reservoirs

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    Lake Fayetteville and Lake Wedington are small reservoirs of about the same size and age that are located in northwestern Arkansas. We collected macrophytes from eleven transects around each reservoir in the autumn of 1993. Justicia (waterwillow), Typha (cat-tail), Scirpus (bulrush), Potamogeton (pondweed), and Zannichellia (horned pondweed) occur in both reservoirs. Justicia occurs most commonly in both reservoirs. The macrophytes of Lake Wedington are organized in a characteristic zonation pattern with bands from shore toward open water of emergent, floating-leaved, then submersed macrophytes. Macrophyte zonation was not as evident in Lake Fayetteville because of the low occurrence of floating leaved and submersed macrophytes in1993. Early studies of Lake Wedington found that the dominant macrophytes were Cyperus, Echinochloa, Lotus, and Sagittaria, all of which were absent during this study. Potamogeton, Scirpus, and Typha were also found to be dominant during 1952 studies, but occurred in lesser amounts in the current study. Previous studies (1956, 1967, 1977) on Lake Fayetteville stated that Sagittaria and Nelumbo were dominant macrophytes, but we found none in1993. Juncus, Potamogeton, Scirpus, and Typha were common in the early studies but occurred infrequently in our collections. Macrophyte composition in Lake Fayetteville in 1993 was attributable to an herbicide application that occurred in spring, 1992. As for the changes in Lake Wedington, we assume that the Justicia has out-competed those macrophytes that were in the reservoir in1952, or that normal lake ontogeny during the intervening 40 years has altered habitat conditions to now favor Justicia

    An investigation of herpes simplex virus promoter activity compatible with latency establishment reveals VP16-independent activation of immediate-early promoters in sensory neurones

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    Herpes simplex virus (HSV) type-1 establishes lifelong latency in sensory neurones and it is widely assumed that latency is the consequence of a failure to initiate virus immediate-early (IE) gene expression. However, using a Ore reporter mouse system in conjunction with Ore-expressing HSV-1 recombinants we have previously shown that activation of the IE ICPO promoter can precede latency establishment in at least 30 % of latently infected cells. During productive infection of non-neuronal cells, IE promoter activation is largely dependent on the transactivator VP16 a late structural component of the virion. Of significance, VP16 has recently been shown to exhibit altered regulation in neurones; where its de novo synthesis is necessary for IE gene expression during both lytic infection and reactivation from latency. In the current study, we utilized the Ore reporter mouse model system to characterize the full extent of viral promoter activity compatible with cell survival and latency establishment. In contrast to the high frequency activation of representative IE promoters prior to latency establishment, cell marking using a virus recombinant expressing Ore under VP16 promoter control was very inefficient. Furthermore, infection of neuronal cultures with VP16 mutants reveals a strong VP16 requirement for IE promoter activity in non-neuronal cells, but not sensory neurones. We conclude that only IE promoter activation can efficiently precede latency establishment and that this activation is likely to occur through a VP16-independent mechanism

    Cyclic cocycles on twisted convolution algebras

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    We give a construction of cyclic cocycles on convolution algebras twisted by gerbes over discrete translation groupoids. For proper \'etale groupoids, Tu and Xu provide a map between the periodic cyclic cohomology of a gerbe-twisted convolution algebra and twisted cohomology groups which is similar to a construction of Mathai and Stevenson. When the groupoid is not proper, we cannot construct an invariant connection on the gerbe; therefore to study this algebra, we instead develop simplicial techniques to construct a simplicial curvature 3-form representing the class of the gerbe. Then by using a JLO formula we define a morphism from a simplicial complex twisted by this simplicial curvature 3-form to the mixed bicomplex computing the periodic cyclic cohomology of the twisted convolution algebras. The results in this article were originally published in the author's Ph.D. thesis.Comment: 39 page

    Juvenile Crisis Intervention Teams (CITs): A Qualitative Description of Current Programs

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    This article describes one of the newest, most specialised law enforcement programmes in the United States: Crisis Intervention Teams (CITs) for youth with mental illness. In response to the fragmentation of behavioural healthcare services in the educational, juvenile justice and mental health systems, JuvenileCITs (J-CITs) have been implemented in a handful of jurisdictions to serve as an intervention for troubled and troublesome adolescents in need of mental health care. Information about J-CITs is limited; little has been written about such programmes, and no published studies have examined their effectiveness. Hence the present study was undertaken to identify all of the currently operational J-CITs in the United States. We conducted structured telephone interviews in order to gather qualitative data regarding the philosophy, origins, operations and components of each J-CIT. We afford an early look at several J-CIT programmes in diverse geographic areas. We conclude with observations concerning the role of such programmes in a law enforcement as well as the challenges that police departments are likely to face in the implementation and maintenance of such initiatives
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