4,816 research outputs found
Genetic variation in the mitochondrial 16S ribosomal RNA gene of Ixodes scapularis (Acari: Ixodidae)
Division of Giardia isolates from humans into two genetically distinct assemblages by electrophoretic analysis of enzyme encoded at 27 loci in comparison with Giardia muris
Giardia that infect humans are known to be heterogeneous but they are assigned currently to a single species, Giardia intestinalis (syn. G. lamblia). The genetic differences that exist within G. intestinalis have not yet been assessed quantitatively and neither have they been compared in magnitude with those that exist between G. intestinalis and species that are morphologically similar (G. duodenalis) or morphologically distinct (e.g. G. muris). In this study, 60 Australian isolates of G. intestinalis were analysed electrophoretically at 27 enzyme loci and compared with G. muris and a feline isolate of G. duodenalis. Isolates of G. intestinalis were distinct genetically from both G. muris (approximately 80% fixed allelic differences) and the feline G. duodenalis isolate (approximately 75% fixed allelic differences). The G. intestinalis isolates were extremely heterogeneous but they fell into 2 major genetic assemblages, separated by fixed allelic differences at approximately 60% of loci examined. The magnitude of the genetic differences between the G. intestinalis assemblages approached the level that distinguished the G. duodenalis isolate from the morphologically distinct G. muris. This raises important questions about the evolutionary relationships of the assemblages with Homo sapiens, the possibility of ancient or contemporary transmission from animal hosts to humans and the biogeographical origins of the two clusters.G. Mayrhofer, R. H. Andrews, P. L. Ey and N. B. Chilto
Revising ethical guidance for the evaluation of programmes and interventions not initiated by researchers
Public health and service delivery programmes, interventions and policies (collectively, ‘programmes’) are typically developed and implemented for the primary purpose of effecting change rather than generating knowledge. Nonetheless, evaluations of these programmes may produce valuable learning that helps determine effectiveness and costs as well as informing design and implementation of future programmes. Such studies might be termed ‘opportunistic evaluations’, since they are responsive to emergent opportunities rather than being studies of interventions that are initiated or designed by researchers. However, current ethical guidance and registration procedures make little allowance for scenarios where researchers have played no role in the development or implementation of a programme, but nevertheless plan to conduct a prospective evaluation. We explore the limitations of the guidance and procedures with respect to opportunistic evaluations, providing a number of examples. We propose that one key missing distinction in current guidance is moral responsibility: researchers can only be held accountable for those aspects of a study over which they have control. We argue that requiring researchers to justify an intervention, programme or policy that would occur regardless of their involvement prevents or hinders research in the public interest without providing any further protections to research participants. We recommend that trial consent and ethics procedures allow for a clear separation of responsibilities for the intervention and the evaluation
On the possibility of magneto-structural correlations: detailed studies of di-nickel carboxylate complexes
A series of water-bridged dinickel complexes of the general formula [Ni<sub>2</sub>(μ<sub>2</sub>-OH<sub>2</sub>)(μ2-
O<sub>2</sub>C<sup>t</sup>Bu)<sub>2</sub>(O<sub>2</sub>C<sup>t</sup>Bu)2(L)(L0)] (L = HO<sub>2</sub>C<sup>t</sup>Bu, L0 = HO<sub>2</sub>C<sup>t</sup>Bu (1), pyridine (2),
3-methylpyridine (4); L = L0 = pyridine (3), 3-methylpyridine (5)) has been synthesized
and structurally characterized by X-ray crystallography. The magnetic properties
have been probed by magnetometry and EPR spectroscopy, and detailed measurements
show that the axial zero-field splitting, D, of the nickel(ii) ions is on the same order as
the isotropic exchange interaction, J, between the nickel sites. The isotropic exchange
interaction can be related to the angle between the nickel centers and the bridging
water molecule, while the magnitude of D can be related to the coordination sphere at
the nickel sites
Trouble at the top: The construction of a tenant identity in the governance of social housing organizations
The project of citizen governance has transformed the social housing sector in England where 20,000 tenants now sit as directors on the boards of housing associations, but the entrance of social housing tenants to the boardroom has aroused opposition from the chief executives of housing companies and triggered regulatory intervention from government inspectors. This paper investigates the cause of these tensions through a theoretical framework drawn from the work of feminist philosopher Judith Butler. It interprets housing governance as an identificatory project with the power to constitute tenant directors as regulated subjects, and presents evidence to suggest that this project of identity fails to completely enclose its subject, allowing tenant directors to engage in ‘identity work’ that threatens the supposed unity of the board. The paper charts the development of antagonism and political tension in the board rooms of housing companies to present an innovative account of the construction and contestation of identities in housing governance
The study of metaphor as part of Critical Discourse Analysis
This article discusses how the study of metaphoric and more generally, figurative language use contributes to critical discourse analysis (CDA). It shows how cognitive linguists’ recognition of metaphor as a fundamental means of concept- and argument-building can add to CDA's account of meaning constitution in the social context. It then discusses discrepancies between the early model of conceptual metaphor theory and empirical data and argues that discursive-pragmatic factors as well as sociolinguistic variation have to be taken into account in order to make cognitive analyses more empirically and socially relevant. In conclusion, we sketch a modified cognitive approach informed by Relevance Theory within CDA
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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