27,614 research outputs found

    A new genus and species of cryptocephaline leaf beetle (Coleoptera: Chrysomelidae) from Costa Rica

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    Aulacothoracicus coastaricensis Watts, new genus and new species of cryoptocephaline Chrysomelidae, is described from Costa Rica. Illustrations and an updated key to the genera of the subfamily in North and Central America are provided

    Examination of a culturable microbial population from the gastrointestinal tract of the wood-eating loricariid catfish Panaque nigrolineatus

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    Fish play a critical role in nutrient cycling and organic matter flow in aquatic environments. However, little is known about the microbial diversity within the gastrointestinal tracts that may be essential in these degradation activities. Panaque nigrolineatus is a loricariid catfish found in the Neotropics that have a rare dietary strategy of consuming large amounts of woody material in its natural environment. As a consequence, the gastrointestinal (GI) tract of P. nigrolineatus is continually exposed to high levels of cellulose and other recalcitrant wood compounds and is, therefore, an attractive, uncharacterized system to study microbial community diversity. Our previous 16S rRNA gene surveys demonstrated that the GI tract microbial community includes phylotypes having the capacity to degrade cellulose and fix molecular nitrogen. In the present study we verify the presence of a resident microbial community by fluorescence microscopy and focus on the cellulose-degrading members by culture-based and 13C-labeled cellulose DNA stable-isotope probing (SIP) approaches. Analysis of GI tract communities generated from anaerobic microcrystalline cellulose enrichment cultures by 16S rRNA gene analysis revealed phylotypes sharing high sequence similarity to known cellulolytic bacteria including Clostridium, Cellulomonas, Bacteroides, Eubacterium and Aeromonas spp. Related bacteria were identified in the SIP community, which also included nitrogen-fixing Azospirillum spp. Our ability to enrich for specialized cellulose-degrading communities suggests that the P. nigrolineatus GI tract provides a favorable environment for this activity and these communities may be involved in providing assimilable carbon under challenging dietary conditions

    The SBI Program and Student Outcomes: A Study of Business Policy Classes

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    This study represents a preliminary inquiry ID to determine the value of combining SBI and Policy into a singular curriculum. A comparison of this combined formal was made wi1h the traditional Policy course. A slightly modified Job Diagnostic Survey (Hackman & Oldham, 1975) and a skills/usefulness scale (Hoffman, Fon1eno1 & Viswanathan, 1990) was administered to assess the difference between the two groups. Results suggested that the combined format met or exceeded the ou1comes of the traditional Policy course

    Exploiting the Design Freedom of RM

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    This paper details how Rapid Manufacturing (RM) can overcome the restrictions imposed by the inherent process limitations of conventional manufacturing techniques and become the enabling technology in fabricating optimal products. A new design methodology capable of exploiting RM’s increased design freedom is therefore needed. Inspired by natural world structures of trees and bones, a multi-objective, genetic algorithm based topology optimisation approach is presented. This combines multiple unit cell structures and varying volume fractions to create a heterogeneous part structure which exhibits a uniform stress distribution.Mechanical Engineerin

    Silencing disease genes in the laboratory and the clinic

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    Synthetic nucleic acids are commonly used laboratory tools for modulating gene expression and have the potential to be widely used in the clinic. Progress towards nucleic acid drugs, however, has been slow and many challenges remain to be overcome before their full impact on patient care can be understood. Antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) are the two most widely used strategies for silencing gene expression. We first describe these two approaches and contrast their relative strengths and weaknesses for laboratory applications. We then review the choices faced during development of clinical candidates and the current state of clinical trials. Attitudes towards clinical development of nucleic acid silencing strategies have repeatedly swung from optimism to depression during the past 20 years. Our goal is to provide the information needed to design robust studies with oligonucleotides, making use of the strengths of each oligonucleotide technology

    Phylogenetic analysis of microbial communities in different regions of the gastrointestinal tract in Panaque nigrolineatus, a wood-eating fish

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    The Neotropical detritivorous catfish Panaque nigrolineatus imbibes large quantities of wood as part of its diet. Due to the interest in cellulose, hemi-cellulose and lignin degradation pathways, this organism provides an interesting model system for the detection of novel microbial catabolism. In this study, we characterize the microbial community present in different regions of the alimentary tract of P. nigrolineatus fed a mixed diet of date palm and palm wood in laboratory aquaria. Analysis was performed on 16S rRNA gene clone libraries derived from anterior and posterior regions of the alimentary tract and the auxiliary lobe (AL), an uncharacterized organ that is vascularly attached to the midgut. Sequence analysis and phylogenetic reconstruction revealed distinct microbial communities in each tissue region. The foregut community shared many phylotypes in common with aquarium tank water and included Legionella and Hyphomicrobium spp. As the analysis moved further into the gastrointestinal tract, phylotypes with high levels of 16S rRNA sequence similarity to nitrogen-fixing Rhizobium and Agrobacterium spp. and Clostridium xylanovorans and Clostridium saccharolyticum, dominated midgut and AL communities. However, the hindgut was dominated almost exclusively by phylotypes with the highest 16S rRNA sequence similarity to the Cytophaga-Flavobacterium-Bacteroides phylum. Species richness was highest in the foregut (Chao(1) = 26.72), decreased distally through the midgut (Chao(1) = 25.38) and hindgut (Chao(1) = 20.60), with the lowest diversity detected in the AL (Chao(1) = 18.04), indicating the presence of a specialized microbial community. Using 16S rRNA gene phylogeny, we report that the P. nigrolineatus gastrointestinal tract possesses a microbial community closely related to microorganisms capable of cellulose degradation and nitrogen fixation. Further studies are underway to determine the role of this resident microbial community in Panaque nigrolineatus

    Towards scalable end-to-end QoS provision for VoIP applications

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    The growth of the Internet and the development of its new applications have increased the demand for providing a certain level of resource assurance and service support. The concept of ensuring quality of service (QoS) has been introduced in order to provide the support and assurance for these services. Different QoS mechanisms, such as integrated services (IntServ) and differentiated services (DiffServ), have been developed and introduced to provide different levels of QoS provision. However, IntServ can suffer from scalability issues that make it infeasible for large-scale network implementations. On the other hand, the aggregated-based per-flow technique of DiffServ does not provide such an end-to-end QoS guarantee. Recently, the IETF have proposed a new QoS architecture that implements IntServ over DiffServ in order to provide an end-to-end QoS for scalable networks. Hence, it became possible to provide and support a certain level of QoS for some delay sensitive and bandwidth-demanding applications such as voice over Internet Protocol (VoIP). With regard to VoIP applications, delay, jitter and packet loss are crucial issues that have to be taken into consideration for any VoIP system design and such parameters need a distinct level of QoS support

    On fictions and wicked problems: towards a social democratic criminology project in the age of neo-liberalism

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    If it is true, as Pat Carlen (2010) claims, that contemporary ‘justice’ policies are exhibiting all the signs of ‘penal populism’ and ‘risk crazed governance’, then social democratic criminologists face the dual challenge of explaining why these policies are not only not working but also how this fact continues to be explained away. At stake here are two central questions: firstly, what grounds are available to secure the intellectual legitimacy of criminology; and, secondly, what ways of knowing could secure the legitimacy of a social-democratic criminology. The paper begins by exploring what is at stake when what appears to be a very large number of criminologists claim that theirs is an ‘empirical scientific’ discipline. The paper argues that neither mainstream criminology nor social democratic criminology can base any claims to intellectual legitimacy by relying on an ‘empirical scientific’ frame. The paper draws on Spencer (1987) to advance the ‘unpalatable thesis’ that, as far as the actual practice by conventional criminologists of their kind of social science goes, ‘they do not know what they are doing’ (Spencer 1987: 333) and that their ignorance of this fact has serious consequences for the progress of their field. The paper shows that there is a gap between the actual practice of conventional criminology and its claims to ‘scientific empiricism’: what is actually on offer is an ‘imperfect empiricism’.The long-forgotten work of Bentham, adumbrated by Vaihinger (1935) and Fuller (1967), is then traced and some of the implications of this theory of fictions for contemporary representations of crime are noted. One implication briefly charted here is that any social democratic criminology needs to rehabilitate the proper role played by fictions as they grapple with the ‘wicked problems’ that currently populate this field. The long-standing affectation of ‘scientific empiricism’ by many practicing criminologists has long camouflaged the inability of conventional criminologists to address what are properly ‘wicked problems’

    THE PROPER PREEMINENT ROLE OF PARENT DISCIPLINES AND LEARNED SOCIETIES IN SETTING THE AGENDA AT LAND GRANT UNIVERSITIES

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    Contrary to recent commentary, reliance on individual faculty initiative and learned societies in setting the academic agenda has greater promise for contributing to the land grant mission than more administratively driven and dominated systems. Learned societies have the advantage in evaluating disciplinary content and are thereby the appropriate evaluators of quality. A distinguishing characteristic of all university professors should be a continuing commitment to active participation in research in support of their principle function, teaching, be their students on-campus undergraduate or graduates, off-campus clientele, or professional peers. The popular notion that all, or even most recognized peer-review journals are oriented mainly to disciplinary (versus problem-focused) research is challenged.Teaching/Communication/Extension/Profession,
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