239 research outputs found
Inferring kangaroo phylogeny from incongruent nuclear and mitochondrial genes
The marsupial genus Macropus includes three subgenera, the familiar large grazing kangaroos and wallaroos of M. (Macropus) and M. (Osphranter), as well as the smaller mixed grazing/browsing wallabies of M. (Notamacropus). A recent study of five concatenated nuclear genes recommended subsuming the predominantly browsing Wallabia bicolor (swamp wallaby) into Macropus. To further examine this proposal we sequenced partial mitochondrial genomes for kangaroos and wallabies. These sequences strongly favour the morphological placement of W. bicolor as sister to Macropus, although place M. irma (black-gloved wallaby) within M. (Osphranter) rather than as expected, with M. (Notamacropus). Species tree estimation from separately analysed mitochondrial and nuclear genes favours retaining Macropus and Wallabia as separate genera. A simulation study finds that incomplete lineage sorting among nuclear genes is a plausible explanation for incongruence with the mitochondrial placement of W. bicolor, while mitochondrial introgression from a wallaroo into M. irma is the deepest such event identified in marsupials. Similar such coalescent simulations for interpreting gene tree conflicts will increase in both relevance and statistical power as species-level phylogenetics enters the genomic age. Ecological considerations in turn, hint at a role for selection in accelerating the fixation of introgressed or incompletely sorted loci. More generally the inclusion of the mitochondrial sequences substantially enhanced phylogenetic resolution. However, we caution that the evolutionary dynamics that enhance mitochondria as speciation indicators in the presence of incomplete lineage sorting may also render them especially susceptible to introgression
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Interview or inquisition: Successful communication techniques (Or what does ethics have to do with it, anyway )
Auditing and being audited can be a very stressful event. The auditor has to be sensitive to the anxiety of all auditees and should do everything possible to put the auditee at ease and help the audit process to proceed smoothly. In this paper, the human factors associated with auditing are discussed and methods of communication and other interfacing techniques are discussed which, hopefully, can act as stress reducers. The bottom-line'' of any audit should be to provide feedback to the auditees that will help validate or improve their process and management system. Reducing the stress and enhancing communication will help to better achieve this goal. Although some evidence during an audit is gathered from records and documents, a significant portion of audit time is spent interviewing the audited organization's personnel. Therefore, much of this paper deals with interview techniques. It is up to the auditor to establish an initial atmosphere of trust and open communication. The goal is to obtain as much valid information as possible in the shortest time possible. Auditors should emphasize that they are there to audit the systems or program, not the person. Auditors should help the auditees' line management view the audit not as a search for the guilty,'' but an audit that will identify problems and assist in correction of existing or potential system problems. It should be the clearly defined policy of any audit program that there be no surprises involved with the evaluation. An ethical audit is not the place for cloak-and-dagger tactics, for witch hunting, or for the identification of situations that are then sprung at a critical and embarrassing time (a gotcha'')
Spin diffusion in the low-dimensional molecular quantum Heisenberg antiferromagnet Cu(pyz)(NO3)2 detected with implanted muons
We present the results of muon-spin relaxation measurements of spin excitations in the one-dimensional quantum Heisenberg antiferromagnet Cu(pyz)(NO3)2. Using density-functional theory we propose muon sites and assess the degree of perturbation the muon probe causes on the system. We identify a site involving the muon forming a hydroxyl-type bond with an oxygen on the nitrate group that is sensitive to the characteristic spin dynamics of the system. Our measurements of the spin dynamics show that in the temperature range TNJ and that in the related two-dimensional system Cu(pyz)2(ClO4)2
Calculating invariants as coreflexive bisimulations
Invariants, bisimulations and assertions are the main ingredients of coalgebra theory applied to software systems. In this paper we reduce the first to a particular case of the second and show how both together pave the way to a theory of coalgebras which regards invariant predicates as types. An outcome of such a theory is a calculus of invariants’ proof obligation discharge, a fragment of which is presented in the paper.
The approach has two main ingredients: one is that of adopting relations as “first class citizens” in a pointfree reasoning style; the other lies on a synergy found between a relational construct, Reynolds’ relation on functions involved in the abstraction theorem on parametric polymorphism and the coalgebraic account of bisimulations and invariants. This leads to an elegant proof of the equivalence between two different definitions of bisimulation found in coalgebra literature (due to B. Jacobs and Aczel & Mendler, respectively) and to their instantiation to the classical Park-Milner definition popular in process algebra.Partially supported by the Fundacao para a Ciencia e a Tecnologia, Portugal, under grant number SFRH/BD/27482/2006
Transverse field muon-spin rotation signature of the skyrmion-lattice phase in Cu2OSeO3
We present the results of transverse field (TF) muon-spin rotation (μ+SR) measurements on Cu2OSeO3, which has a skyrmion-lattice (SL) phase. We measure the response of the TF μ+SR signal in that phase along with the surrounding ones, and suggest how the phases might be distinguished using the results of these measurements. Dipole field simulations support the conclusion that the muon is sensitive to the SL via the TF line shape and, based on this interpretation, our measurements suggest that the SL is quasistatic on a time scale τ > 100 ns
Anomalous magnetic exchange in a dimerized quantum magnet composed of unlike spin species
We present here a study of the magnetic properties of the antiferromagnetic dimer material CuVOF 4 ( H 2 O ) 6 ⋅ H 2 O , in which the dimer unit is composed of two different S = 1 / 2 species, Cu(II) and V(IV). An applied magnetic field of μ 0 H c 1 = 13.1 ( 1 ) T is found to close the singlet-triplet energy gap, the magnitude of which is governed by the antiferromagnetic intradimer J 0 ≈ 21 K, and interdimer J ′ ≈ 1 K, exchange energies, determined from magnetometry and electron-spin resonance measurements. The results of density functional theory (DFT) calculations are consistent with the experimental results. The DFT calculations predict antiferromagnetic coupling along all nearest-neighbor bonds, with the magnetic ground state comprising spins of different species aligning antiparallel to one another, while spins of the same species are aligned parallel. The magnetism in this system cannot be accurately described by the overlap between localized V orbitals and magnetic Cu orbitals lying in the Jahn-Teller (JT) plane, with a tight-binding model based on such a set of orbitals incorrectly predicting that interdimer exchange should be dominant. DFT calculations indicate significant spin density on the bridging oxide, suggesting instead an unusual mechanism in which intradimer exchange is mediated through the O atom on the Cu(II) JT axis
Implementation of a pharmacogenomics consult service to support the INGENIOUS trial
Hospital systems increasingly utilize pharmacogenomic testing to inform clinical prescribing. Successful implementation efforts have been modeled at many academic centers. In contrast, this report provides insights into the formation of a pharmacogenomics consultation service at a safety-net hospital, which predominantly serves low-income, uninsured, and vulnerable populations. The report describes the INdiana GENomics Implementation: an Opportunity for the UnderServed (INGENIOUS) trial and addresses concerns of adjudication, credentialing, and funding
Observables from a solution of 1+3 dimensional relativistic hydrodynamics
In this paper we analyze a 1+3 dimensional solution of relativistic
hydrodynamics. We calculate momentum distribution and other observables from
the solution and compare them to measurements from the Relativistic Heavy Ion
Collider (RHIC). We find that the solution we analyze is compatible with the
data. In the last several years many numerical models were tested, but it is
the first time that an exact, parametric, 1+3 dimensional relativistic solution
is compared to data.Comment: 6 pages, 6 figures. Published in EPJ A. This work was supported by
the OTKA grant NK73143 and M. Csanad's Bolyai scholarshi
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In the social factory? Immaterial labour, precariousness and cultural work
This article introduces a special section concerned with precariousness and cultural work. Its aim is to bring into dialogue three bodies of ideas -- the work of the autonomous Marxist 'Italian laboratory'; activist writings about precariousness and precarity; and the emerging empirical scholarship concerned with the distinctive features of cultural work, at a moment when artists, designers and (new) media workers have taken centre stage as a supposed 'creative class' of model entrepreneurs.
The paper is divided into three sections. It starts by introducing the ideas of the autonomous Marxist tradition, highlighting arguments about the autonomy of labour, informational capitalism and the 'factory without walls', as well as key concepts such as multitude and immaterial labour. The impact of these ideas and of Operaismo politics more generally on the precarity movement is then considered in the second section, discussing some of the issues that have animated debate both within and outside this movement, which has often treated cultural workers as exemplifying the experiences of a new 'precariat'. In the third and final section of the paper we turn to the empirical literature about cultural work, pointing to its main features before bringing it into debate with the ideas already discussed. Several points of overlap and critique are elaborated -- focusing in particular on issues of affect, temporality, subjectivity and solidarity
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