Mapping class groups and outer automorphism groups of free groups are C*-simple

We prove that the reduced C*-algebras of centerless mapping class groups and outer automorphism groups of free groups are simple, as are the irreducible pure subgroups of mapping class groups and the analogous subgroups of outer automorphism groups of free groups.Comment: 10 pages, amstex. J. Functional Analysis, to be publishe

The Chabauty space of closed subgroups of the three-dimensional Heisenberg group

When equipped with the natural topology first defined by Chabauty, the closed subgroups of a locally compact group $G$ form a compact space \Cal C(G). We analyse the structure of \Cal C(G) for some low-dimensional Lie groups, concentrating mostly on the 3-dimensional Heisenberg group $H$. We prove that \Cal C(H) is a 6-dimensional space that is path--connected but not locally connected. The lattices in $H$ form a dense open subset \Cal L(H) \subset \Cal C(H) that is the disjoint union of an infinite sequence of pairwise--homeomorphic aspherical manifolds of dimension six, each a torus bundle over $(\bold S^3 \smallsetminus T) \times \bold R$, where $T$ denotes a trefoil knot. The complement of \Cal L(H) in \Cal C(H) is also described explicitly. The subspace of \Cal C(H) consisting of subgroups that contain the centre $Z(H)$ is homeomorphic to the 4--sphere, and we prove that this is a weak retract of \Cal C(H).Comment: Minor edits. Final version. To appear in the Pacific Journal. 41 pages, no figure

Good Governance in Public Procurement: A South African Case Study

In this article good governance in public procurement, with particular reference to accountability is discussed. The principle of providing adequate remedies in public procurement is put under the spotlight. This is done with reference to the decision in Steenkamp NO v Provincial Tender Board, Eastern Cape. In this case the Constitutional Court had to consider whether an initially successful tenderer could lodge a delictual claim for damages to compensate for expenses incurred after conclusion of a contract, which was subsequently rendered void on an application for review of the tender award. The applicable principles of good governance and the applicable provisions of the UNCITRAL Model Law on Public Procurement and the WTO plurilateral Government Procurement Agreement are analysed. This is done to enable an evaluation of the decision by the Constitutional Court in the above case. It is concluded that the South African public procurement system does in this instance comply with the basic principles of good governance with regard to accountability.PER/PELJ Vol. 2 2008: pp. 1-4

Which finitely generated Abelian groups admit isomorphic Cayley graphs?

We show that Cayley graphs of finitely generated Abelian groups are rather rigid. As a consequence we obtain that two finitely generated Abelian groups admit isomorphic Cayley graphs if and only if they have the same rank and their torsion parts have the same cardinality. The proof uses only elementary arguments and is formulated in a geometric language.Comment: 16 pages; v2: added reference, reformulated quasi-convexity, v3: small corrections; to appear in Geometriae Dedicat

Online counselling services for Youth@risk

Youth today suffer from many socio-economic problems and struggle to operate in the current economic environment. Wellbeing service provision to youth@risk is inadequate to deal with the complexities of societal challenges which are amplified by the fast technology advances in a continuously changing environment. This paper aims to consider the provision of online counselling to enhance current face-to-face services from the provider’s perspective. The case of a volunteer-based online counselling service that has been in operation since 2010 is considered to establish the aspects that influence this type pf service. Related literature was reviewed to determine the issues reported from current studies and a taxonomy of digital services was used to analyse the service objectives of the service provider. Data collected from sessions with the facilitators and observations of a chat session was analysed to establish their experience of online counselling. The findings were interpreted to answer the research question. The contribution of this paper is in response to the many appeals for more empirical research on real cases. It can be concluded that an online counselling service is a viable extension of face-to-face counselling but more research is needed to understand its benefit to the clients and the ability to ensure a sustained service, especially in developing contexts

Strongly bounded groups and infinite powers of finite groups

We define a group as strongly bounded if every isometric action on a metric space has bounded orbits. This latter property is equivalent to the so-called uncountable strong cofinality, recently introduced by G. Bergman. Our main result is that G^I is strongly bounded when G is a finite, perfect group and I is any set. This strengthens a result of Koppelberg and Tits. We also prove that omega_1-existentially closed groups are strongly bounded.Comment: 10 pages, no figure. Versions 1-3 were entitled "Uncountable groups with Property (FH)". To appear in Comm. Algebr

Profinite completion of Grigorchuk's group is not finitely presented

In this paper we prove that the profinite completion $\mathcal{\hat G}$ of the Grigorchuk group $\mathcal{G}$ is not finitely presented as a profinite group. We obtain this result by showing that H^2(\mathcal{\hat G},\field{F}_2) is infinite dimensional. Also several results are proven about the finite quotients $\mathcal{G}/ St_{\mathcal{G}}(n)$ including minimal presentations and Schur Multipliers

Procurement Under the Uncitral Model Law: A Southern Africa Perspective

In Africa, economic integration, realised through regional integration, is seen as one of the driving factors that will improve the lives of its people. To enable regionalisation, economic growth and to unlock the potential of Africa its infrastructure will have to be improved. Infrastructure will on the whole be realised through public procurement. The stages for opening up procurement markets, referred to by Yukins and Schooner, is discussed and it is concluded that the states in SADC is still in the initial stages of opening its public procurement markets for regional competition. Although COMESA is not yet in full compliance with all four the stages great strides have been made and have elements of all stages been addressed. Because of the influence the Model Law has already played in COMESA, and the rest of Africa, it would be contra productive should SADC not take the same route as COMESA. If regard is had to the four categories of procurement rules that serves as barriers to national procurement markets, as set out by Arrowsmith it is clear that all of these are present in most SADC member states. Also in the case of COMESA these barriers still exist albeit to a lesser extent. What is necessary is a phased approach to address all of these barriers. This will be possible under the UNCITRAL Model Law as the 2011 Model Law does provide for the possibility of complying with international obligations and for states to allow for socio economic objectives in their procurement regimes. There can be little doubt that the 1994 Model Law has already had a marked influence on public procurement regulation in Africa and that the 2011 Model Law will in future continue to do so. Public procurement is essential for economic development and is the integration and harmonisation thereof on a regional basis the first step In this regard SADC, and especially South Africa, has an important role to play.   &nbsp

Caffeine intake, plasma caffeine level, and kidney function: a Mendelian randomization study

Caffeine is a psychoactive substance widely consumed worldwide, mainly via sources such as coffee and tea. The effects of caffeine on kidney function remain unclear. We leveraged the genetic variants in the CYP1A2 and AHR genes via the two-sample Mendelian randomization (MR) framework to estimate the association of genetically predicted plasma caffeine and caffeine intake on kidney traits. Genetic association summary statistics on plasma caffeine levels and caffeine intake were taken from genome-wide association study (GWAS) meta-analyses of 9876 and of >47,000 European ancestry individuals, respectively. Genetically predicted plasma caffeine levels were associated with a decrease in estimated glomerular filtration rate (eGFR) measured using either creatinine or cystatin C. In contrast, genetically predicted caffeine intake was associated with an increase in eGFR and a low risk of chronic kidney disease. The discrepancy is likely attributable to faster metabolizers of caffeine consuming more caffeine-containing beverages to achieve the same pharmacological effect. Further research is needed to distinguish whether the observed effects on kidney function are driven by the harmful effects of higher plasma caffeine levels or the protective effects of greater intake of caffeine-containing beverages, particularly given the widespread use of drinks containing caffeine and the increasing burden of kidney disease