27,424 research outputs found
On computation of the first Baues--Wirsching cohomology of a freely-generated small category
The Baues--Wirsching cohomology is one of the cohomologies of a small
category. Our aim is to describe the first Baues--Wirsching cohomology of the
small category generated by a finite quiver freely. We consider the case where
the coefficient is a natural system obtained by the composition of a functor
and the target functor. We give an algorithm to obtain generators of the vector
space of inner derivations. It is known that there exists a surjection from the
vector space of derivations of the small category to the first Baues--Wirsching
cohomology whose kernel is the vector space of inner derivations.Comment: 11 page
A guide to performing skin-prick testing in practice: tips and tricks of the trade
Atopy can manifest in childhood as infantile eczema (atopic dermatitis), allergic rhinitis and asthma. In practice, it is critical to identify the offending allergen in atopic individuals. This will not only influence therapeutic interventions, but may also have a significant impact on the individualâs quality of life. The most common clinical test for allergy detection is the introduction of an allergen directly into the skin in the form of a skin-prick test. Skin-prick testing is recommended in the diagnostic workup for allergies because it is reliable, safe, convenient, inexpensive, minimally invasive, and has the advantage of multiple allergen testing in one, 15- to 20-minute, test. Skin-prick testing can be performed from birth onwards. Although there is a small risk of developing anaphylaxis, the test remains safe to perform in a consultation room or at the patientâs bedside. Worldwide, a skin-prick test remains the test of choice for allergy because of its convenience and cost-effectiveness. A globally accepted guideline for skin-prick testing is still lacking and would be beneficial to both patient and physician.Keywords: allergy, indications, contraindications, cut-off points, measurement
Aspects of Diffeomorphism and Conformal invariance in classical Liouville theory
The interplay between the diffeomorphism and conformal symmetries (a feature
common in quantum field theories) is shown to be exhibited for the case of
black holes in two dimensional classical Liouville theory. We show that
although the theory is conformally invariant in the near horizon limit, there
is a breaking of the diffeomorphism symmetry at the classical level. On the
other hand, in the region away from the horizon, the conformal symmetry of the
theory gets broken with the diffeomorphism symmetry remaining intact.Comment: Accepted in Euro. Phys. Letters., Title changed, abstract modified,
major modifications made in the pape
The value of pimecrolimus in improving quality of life of children with severe eczema â an open non-randomised study
Background: Atopic eczema is a common skin condition. It has the potential to severely impair quality of life in affected children. Pimecrolimus is currently registered for mild-moderate eczema but in clinical practice children with more severe disease are often treated with this therapy in an attempt to find a safe addition to long-term topical corticosteroid usage. The aim of this study was to test the value of pimecrolimus in improving quality of life in children with severe atopic eczema.Methods: This a single site, phase 4, non-randomised, open label trial of pimecrolimus use in children aged 4 months to 12 years living withmoderate to very severe atopic eczema. The study was conducted at Steve Biko Academic Hospital. Patients with unsatisfactorily controlled disease despite conventional topical therapy, adequate use of emollients, allergen avoidance and non-pharmacological skin hygiene were enrolled. A ParentIndex Quality of Life Questionnaire was completed by parents before and three months after using pimecrolimus.Results: A total of 24 patients were recruited, 20 of whom completed the study. Ninety per cent of patients had co-morbid asthma and allergicrhinitis. The Parent Index Quality of Life demonstrated a mean 33% score improvement after the use of pimecrolimus. There was an attendant reduction in cost of therapy to these patients.Conclusions: Pimecrolimus usage should be extended to patients with more severe atopic eczema as the improvement in quality of life is important and demonstrable.Keywords: severe eczema; topical steroids; calcineurin inhibitors; pimecrolimus; quality of lif
Supersymmetric Quantum Mechanics for String-Bits
We develop possible versions of supersymmetric single particle quantum
mechanics, with application to superstring-bit models in view. We focus
principally on space dimensions , the transverse dimensionalities of
superstring in space-time dimensions. These are the cases for which
``classical'' superstring makes sense, and also the values of for which
Hooke's force law is compatible with the simplest superparticle dynamics. The
basic question we address is: When is it possible to replace such harmonic
force laws with more general ones, including forces which vanish at large
distances? This is an important question because forces between string-bits
that do not fall off with distance will almost certainly destroy cluster
decomposition. We show that the answer is affirmative for , negative for
, and so far inconclusive for .Comment: 17 pages, Late
Effects of the background radiation on radio pulsar and supernova remnant searches and the birth rates of these objects
In different directions of the Galaxy the Galactic background radio radiation
and radiation of complex star formation regions which include large number of
OB associations have different influences on radio pulsar (PSR) and supernova
remnant (SNR) searches. In this work we analyse the effects of these background
radiations on the observations of PSRs at 1400 MHz and SNRs at 1000 MHz. In the
interval l=0 the PSRs with flux F0.2 mJy and the SNRs
with surface brightness WmHzsr are
observable for all values of l and b. All the SNRs with
WmHzsr can be observed in the
interval 60l. We have examined samples of PSRs and SNRs to
estimate the birth rates of these objects in the region up to 3.2 kpc from the
Sun and also in the Galaxy. The birth rate of PSRs is about one in 200 years
and the birth rate of SNRs is about one in 65 years in our galaxy.Comment: revised versio
Complete solution of a constrained tropical optimization problem with application to location analysis
We present a multidimensional optimization problem that is formulated and
solved in the tropical mathematics setting. The problem consists of minimizing
a nonlinear objective function defined on vectors over an idempotent semifield
by means of a conjugate transposition operator, subject to constraints in the
form of linear vector inequalities. A complete direct solution to the problem
under fairly general assumptions is given in a compact vector form suitable for
both further analysis and practical implementation. We apply the result to
solve a multidimensional minimax single facility location problem with
Chebyshev distance and with inequality constraints imposed on the feasible
location area.Comment: 20 pages, 3 figure
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