12,241 research outputs found
Responses of salmonids to habitat changes
Streams in western North America provide spawning and rearing habitats for several species of salmon and trout that are of substantial economic importance in the region. Timber that grows on lands through which these streams flow is also economically important, and its harvest can substantially change habitat conditions and aquatic production in salmonid streams. Undisturbed forests, the streams that flow through them, and the salmonid communities in these streams have intrinsic scientific, genetic, and cultural values in addition to their economic importance. The complex relations between salmonids and their physical environment, and the changes in these relations brought about by timber harvest, have been investigated extensively (see the bibliography by Macdonald et al. 1988). However, in spite of considerable evidence of profound changes in channel morphology and in light, temperature, and flow regimes associated with timber harvests, much uncertainty exists about the responses of salmonids to these changes
Industry structure, procurement and innovation in the UK defence sector
There is agreement within industrial organisation economics that an inverted U-shape relationship exists between the level of competition in an industry and the level of innovation in that industry. Thus, when consolidation changes the level of competition in an industry we might expect this to have implications for the level of innovation in that industry. The key question for our paper is whether the sort of relationship found to hold, on average, across all of manufacturing industry applies in the specific case of the defence industry. We note that the defence industry has unusual structural characteristics and in particular a single (monopsony) buyer on the demand side that can determine the number of competitors in the industry by imposing regulatory barriers to entry, use its contract terms to control the profits that companies make, and support industry innovation through funding R&D by industry and in its own research facilities. We present data on changes to the structure of the UK defence industry and patterns of innovation, 1989-2007. We note in particular that industry consolidation has been accompanied by a steep decline in industry's own funded defence R&D (an input measure of innovation). We argue that this may be explained in part by changes in industry structure but that industry competition is not the whole story. We argue that another part of the explanation relates to public policy: changes in the level of demand, procurement reform and the changing character of demand have all played a part in reducing both the opportunities and incentives for defence industry innovation. We also offer a third explanation, namely that changes in the nature of defence innovation may themselves in part have driven consolidation. We conclude by considering the concerns of UK policy makers about the decline in industry's own funded defence R&D and the policy options that may be open to them
Manipulating Self-Assembly in Silver(I) Complexes of 1,3-Di-\u3cem\u3eN\u3c/em\u3e-pyrazolylorganyls
Three di-N-pyrazolylorganyls with different conformational flexibilities in the three-atom organyl spacers have been prepared, and the self-assembly properties with AgBF4 have been studied both in solution and in the solid state. All ligands give low-coordinate silver(I) centers that are capable of participating in multiple noncovalent interactions, but only the rigid 1,8-dipyrazolylnaphthalene ligand promotes very short Ag−Ag contacts
Completeness of the Leibniz Field and Rigorousness of Infinitesimal Calculus
We present a characterization of the completeness of the field of real
numbers in the form of a \emph{collection of ten equivalent statements}
borrowed from algebra, real analysis, general topology and non-standard
analysis. We also discuss the completeness of non-Archimedean fields and
present several examples of such fields. As an application we exploit one of
our results to argue that the Leibniz infinitesimal calculus in the
century was already a rigorous branch of mathematics -- at
least much more rigorous than most contemporary mathematicians prefer to
believe. By advocating our particular historical point of view, we hope to
provoke a discussion on the importance of mathematical rigor in mathematics and
science in general. We believe that our article will be of interest for those
readers who teach courses on abstract algebra, real analysis, general topology,
logic and the history of mathematics.Comment: 3
Riots and Political Protest: Notes from the Post-Political Present
The years 2008 to 2013 saw a new generation of political protestors take to the streets. Riots disrupted many Western cities and new protest movements emerged, keen to address a bleak context of economic collapse and austerity politics.
In this groundbreaking new study, Winlow, Hall, Briggs and Treadwell push past the unworldly optimism of the liberal left to offer an illuminating account of the enclosure and vacuity of contemporary politics. Focusing on the English riots of 2011, the ongoing crisis in Greece, the Indignados, 15M and Podemos in Spain, the Occupy movement in New York and London and the English Defence League in northern England, this book uses original empirical data to inform a strident theoretical critique of our post-political present. It asks: what are these protest groups fighting for, and what are the chances of success?
Written by leading criminological theorists and researchers, this book makes a major contribution to contemporary debates on social order, politics and cultural capitalism. It illuminates the epochal problems we face today. Riots and Political Protest is essential reading for academics and students engaged in the study of political sociology, criminological theory, political theory, sociological theory and the sociology of deviance.No data (2015)UE
The importance of tau leptons for supersymmetry searches at the Tevatron
Supersymmetry is perhaps most effectively probed at the Tevatron through
production and decay of weak gauginos. Most of the analyses of weak gaugino
observables require electrons or muons in the final state. However, it is
possible that the gauginos will decay primarily to tau leptons, thus
complicating the search for supersymmetry. The motivating reasons for high tau
multiplicity final states are discussed in three approaches to supersymmetry
model building: minimal supergravity, gauge mediated supersymmetry breaking,
and more minimal supersymmetry. The concept of ``e/mu/tau candidate'' is
introduced, and an observable with three e/mu/tau candidates is defined in
analog to the trilepton observable. The maximum mass reach for supersymmetry is
then estimated when gaugino decays to tau leptons have full branching fraction.Comment: 9 pages, latex, 2 figures. Presented at the D0 New Phenomena
Workshop, UC Davis, 26-28 March 199
Evidence of Gene Conversion in Genes Encoding the Gal/GalNac Lectin Complex of Entamoeba
The human gut parasite Entamoeba histolytica, uses a lectin complex on its cell surface to bind to mucin and to ligands on the intestinal epithelia. Binding to mucin is necessary for colonisation and binding to intestinal epithelia for invasion, therefore blocking this binding may protect against amoebiasis. Acquired protective immunity raised against the lectin complex should create a selection pressure to change the amino acid sequence of lectin genes in order to avoid future detection. We present evidence that gene conversion has occurred in lineages leading to E. histolytica strain HM1:IMSS and E. dispar strain SAW760. This evolutionary mechanism generates diversity and could contribute to immune evasion by the parasites
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