7,035 research outputs found
Cooperation between interleukin-5 and the chemokine eotaxin to induce eosinophil accumulation in vivo.
Experiments were designed to study the effect of systemically administered IL-5 on local eosinophil accumulation induced by the intradermal injection of the chemokine eotaxin in the guinea pig. Intravenous interleukin-5 (IL-5) stimulated a rapid and dramatic increase in the numbers of accumulating eosinophils induced by i.d.-injected eotaxin and, for comparison, leukotriene B4. The numbers of locally accumulating eosinophils correlated directly with a rapid increase in circulating eosinophils: circulating eosinophil numbers were 13-fold higher 1 h after intravenous IL-5 (18.3 pmol/kg). This increase in circulating cells corresponded with a reduction in the number of displaceable eosinophils recovered after flushing out the femur bone marrow cavity. Intradermal IL-5, at the doses tested, did not induce significant eosinophil accumulation. We propose that these experiments simulate important early features of the tissue response to local allergen exposure in a sensitized individual, with eosinophil chemoattractant chemokines having an important local role in eosinophil recruitment from blood microvessels, and IL-5 facilitating this process by acting remotely as a hormone to stimulate the release into the circulation of a rapidly mobilizable pool of bone marrow eosinophils. This action of IL-5 would be complementary to the other established activities of IL-5 that operate over a longer time course
The Einstein-Cartan-Elko system
The present paper analyses the Einstein-Cartan theory of gravitation with
Elko spinors as sources of curvature and torsion. After minimally coupling the
Elko spinors to torsion, the spin angular momentum tensor is derived and its
structure is discussed. It shows a much richer structure than the Dirac
analogue and hence it is demonstrated that spin one half particles do not
necessarily yield only an axial vector torsion component. Moreover, it is
argued that the presence of Elko spinors partially solves the problem of
minimally coupling Maxwell fields to Einstein-Cartan theory.Comment: 12 pages, no figure
The Einstein-Elko system -- Can dark matter drive inflation?
Recently, a spin one half matter field with mass dimension one was
discovered, called Elko spinors. The present work shows how to introduce these
fields into a curved spacetime by the standard covariantisation scheme. After
formulating the coupled Einstein-Elko field equations, the spacetime is assumed
to be homogeneous and isotropic in order to simplify the resulting field
equations. Analytical ghost Elko solutions are constructed which have vanishing
energy-momentum tensor without and with cosmological constant. The cosmological
Elko theory is finally related to the standard scalar field theory with self
interaction that gives rise to inflation and it is pointed out that the Elko
spinors are not only prime dark matter candidates but also prime candidates for
inflation.Comment: 24 page
Inter- and intraobserver agreement for diagnosing presumptive ischemic myelopathy and acute noncompressive nucleus pulposus extrusion in dogs using magnetic resonance imaging
Developing a Core Competency Model and Educational Framework for Primary Maternity Services: A national consensus approach
Background: An appropriately educated and competent workforce is crucial to an effective health care system. The National Health Workforce Taskforce (now Health Workforce Australia) and the Maternity Services Inter-Jurisdictional Committee funded a project to develop Core Competencies and Educational Framework for Primary Maternity Services in Australia. These competencies recognise the interdisciplinary nature of maternity care in Australia where care is provided by general practitioners, obstetricians and midwives as well as other professionals. Participants: Key stakeholders from professional organisations and providers of services related to maternity care and consumers of services. Methods: A national consensus approach was undertaken using consultation processes with a Steering Committee, a wider Reference Group and public consultation. Findings: A national Core Competencies and Educational Framework for Primary Maternity Services in Australia was developed through an iterative process with a range of key stakeholders. There are a number of strategies that may assist in the integration of these into primary maternity service provider professional groups' education and practice. Conclusions: The Core Competencies and Educational Framework are based on an interprofessional approach to learning and primary maternity service practice. They have sought to value professional expertise and stimulate awareness and respect for the roles of all primary maternity service providers. The competencies and framework described in this paper are now a critical component of Australian maternity services as they are included in actions in the newly released National Maternity Services Plan and thus have relevance for all providers of Australian maternity services. © 2011 Australian College of Midwives
Eotaxin: a potent eosinophil chemoattractant cytokine detected in a guinea pig model of allergic airways inflammation.
Eosinophil accumulation is a prominent feature of allergic inflammatory reactions, such as those occurring in the lung of the allergic asthmatic, but the endogenous chemoattractants involved have not been identified. We have investigated this in an established model of allergic inflammation, using in vivo systems both to generate and assay relevant activity. Bronchoalveolar lavage (BAL) fluid was taken from sensitized guinea pigs at intervals after aerosol challenge with ovalbumin. BAL fluid was injected intradermally in unsensitized assay guinea pigs and the accumulation of intravenously injected 111In-eosinophils was measured. Activity was detected at 30 min after allergen challenge, peaking from 3 to 6 h and declining to low levels by 24 h. 3-h BAL fluid was purified using high performance liquid chromatography techniques in conjunction with the skin assay. Microsequencing revealed a novel protein from the C-C branch of the platelet factor 4 superfamily of chemotactic cytokines. The protein, eotaxin, exhibits homology of 53% with human MCP-1, 44% with guinea pig MCP-1, 31% with human MIP-1α, and 26% with human RANTES. Laser desorption time of flight mass analysis gave four different signals (8.15, 8.38, 8.81, and 9.03 kD), probably reflecting differential O-glycosylation. Eotaxin was highly potent, inducing substantial 111In-eosinophil accumulation at a 1-2-pmol dose in the skin, but did not induce significant 111In-neutrophil accumulation. Eotaxin was a potent stimulator of both guinea pig and human eosinophils in vitro. Human recombinant RANTES, MIP-1α, and MCP-1 were all inactive in inducing 111In-eosinophil accumulation in guinea pig skin; however, evidence was obtained that eotaxin shares a binding site with RANTES on guinea pig eosinophils. This is the first description of a potent eosinophil chemoattractant cytokine generated in vivo and suggests the possibility that similar molecules may be important in the human asthmatic lung
Quantum state transformations and the Schubert calculus
Recent developments in mathematics have provided powerful tools for comparing
the eigenvalues of matrices related to each other via a moment map. In this
paper we survey some of the more concrete aspects of the approach with a
particular focus on applications to quantum information theory. After
discussing the connection between Horn's Problem and Nielsen's Theorem, we move
on to characterizing the eigenvalues of the partial trace of a matrix.Comment: 40 pages. Accepted for publication in Annals of Physic
Trapped surfaces, horizons and exact solutions in higher dimensions
A very simple criterion to ascertain if (D-2)-surfaces are trapped in
arbitrary D-dimensional Lorentzian manifolds is given. The result is purely
geometric, independent of the particular gravitational theory, of any field
equations or of any other conditions. Many physical applications arise, a few
shown here: a definition of general horizon, which reduces to the standard one
in black holes/rings and other known cases; the classification of solutions
with a (D-2)-dimensional abelian group of motions and the invariance of the
trapping under simple dimensional reductions of the
Kaluza-Klein/string/M-theory type. Finally, a stronger result involving closed
trapped surfaces is presented. It provides in particular a simple sufficient
condition for their absence.Comment: 7 pages, no figures, final version to appear in Class. Quantum Gra
The signed loop approach to the Ising model: foundations and critical point
The signed loop method is a beautiful way to rigorously study the
two-dimensional Ising model with no external field. In this paper, we explore
the foundations of the method, including details that have so far been
neglected or overlooked in the literature. We demonstrate how the method can be
applied to the Ising model on the square lattice to derive explicit formal
expressions for the free energy density and two-point functions in terms of
sums over loops, valid all the way up to the self-dual point. As a corollary,
it follows that the self-dual point is critical both for the behaviour of the
free energy density, and for the decay of the two-point functions.Comment: 38 pages, 7 figures, with an improved Introduction. The final
publication is available at link.springer.co
Quantum dynamics in a time-dependent cylindrical trap
Solutions to the Schr\"{o}dinger equation are examined for a particle inside
a cylindrical trap of a circular time-dependent cross-section. Analytical
expressions for energy and momentum expectation values are derived with respect
to the exact solutions; and the adiabatic and sudden change of the boundary are
discussed. The density profile as a function of time in a given observation
point, resembles the diffraction-in-time pattern observed in a suddenly
released particle but with an enhanced fringe visibility. Numerical
computations are presented for both contracting and expanding boxes.Comment: Accepted by Physics Letters
- …
