Emergent relativistic-like Kinematics and Dynamical Mass Generation for a Lifshitz-type Yukawa model

We study the Infra Red (IR) limit of dispersion relations for scalar and fermion fields in a Lifshitz-type Yukawa model, after dressing by quantum fluctuations. Relativistic-like dispersion relations emerge dynamically in the IR regime of the model, after quantum corrections are taken into account. In this regime, dynamical mass generation also takes place, but in such a way that the particle excitations remain massive, even if the bare masses vanish. The group velocities of the corresponding massive particles of course are smaller than the speed of light, in a way consistent with the IR regime where the analysis is performed. We also comment on possible extensions of the model where the fermions are coupled to an Abelian gauge field

Comments on branon dressing and the Standard Model

This technical note shows how Electrodynamics and a Yukawa model are dressed after integrating out perturbative brane fluctuations, and it is found that first order corrections in the inverse of the brane tension occur for the fermion and scalar wave functions, the couplings and the masses. Nevertheless, field redefinitions actually lead to effective actions where only masses are dressed to this first order. We compare our results with the literature and find discrepancies at the next order, which, however, might not be measurable in the valid regime of low-energy brane fluctuations.Comment: 12 page

Branon stabilization from fermion-induced radiative corrections

We consider a 3-brane embedded in 5-dimensional space time characterized by a Gaussian warp factor, for which the four-dimensional effective theory for brane fluctuation (branons) is unstable. We show that radiative corrections arising from fermions living on the brane, and therefore coupled to branons, stabilize the system by generating dynamically a spontaneous symmetry breaking for the branon field. The price to pay, for the corresponding mechanism to be consistent, is to have a large number of fermion flavours, and we discuss the fat brane scenario as an interpretation for the dressed branon theory, taking into account the Maxwell construction, which avoids the spinodal instability present in the perturbative effective potential.Comment: 7 page

Cancer prevalence in 129 breast-ovarian cancer families tested for BRCA1 and BRCA2 mutations

Background. Women who carry germline mutations in the breast-ovarian cancer susceptibility genes, BRCA1 and BRCA2, are at very high risk of developing breast and/or ovarian cancer. Both genes are tumour suppressor genes that protect all cells from deregulation, and there are reports of their involvement in other cancers that vary and seem to depend on the population investigated. It is therefore important to investigate the other associated cancers in different populations to assist with risk assessments. Objectives. To assess the cancer risk profile in BRCA-mutation-positive and negative South African breast-ovarian cancer families, mainly of Caucasian origin. Design. Descriptive study in which the prevalence of all cancers in the pedigrees of BRCA1- and BRCA2-mutation-positive groups and a group of families without mutations in either gene were compared with the general population. Results. As expected, female breast and ovarian cancer was significantly increased in all three groups. Furthermore, male breast cancer was significantly elevated in the BRCA2-positive and BRCA-negative groups. Stomach cancer prevalence was significantly elevated in the BRCA2-positive families compared with the general population. Conclusions. These results can be applied in estimation of cancer risks and may contribute to more comprehensive counselling of mutation-positive Caucasian breast and/or ovarian cancer families

Tightening the noose: African women and influx control in South Africa 1950-1980.

Apartheid legislation, urbanisatio

Unemployment and 'informal' income-earning activity in Soweto. Part II

African Studies Seminar series. Paper presented 11 August 1980In Part I of this collective work, we attempted to conceptualise in a rigorous fashion the nature and distinguishing characteristics of certain of the economic activities conventionally subsumed under the banner of the 'informal sector'. The analytical sterility of this term has now been widely recognized.(1) In reaction to the uncritical acceptance of the dualism inherent in the 'informal’/ 'formal' dichotomy and its translation into a series of policy proposals (2) by orthodox development theorists, a growing body of literature has focussed attention on the complex linkages and asymmetrically dependent relationships of the continuum of activities which cut across this division. … In this paper, our attempt to conceptualise 'informal' economic activity within the broad perspective of the overall reproduction of capitalist social relations will be developed around the central problem of the reproduction of capital's labour force. The particular focus of the paper will be on the relationship between certain aspects of the struggles of capital and labour over the way in which this process unfolds and the concept of the family a household unit as the primary site of the process in capitalist societ

Cancer prevalence in 129 breast-ovarian cancer families tested for BRCA1 and BRCA2 mutations

BACKGROUND: Women who carry germline mutations in the breast-ovarian cancer susceptibility genes, BRCA1 and BRCA2, are at very high risk of developing breast and / or ovarian cancer. Both genes are tumour suppressor genes that protect all cells from deregulation, and there are reports of their involvement in other cancers that vary and seem to depend on the population investigated. It is therefore important to investigate the other associated cancers in different populations to assist with risk assessments. OBJECTIVES: To assess the cancer risk profile in BRCA-mutation-positive and negative South African breast-ovarian cancer families, mainly of Caucasian origin. DESIGN: Descriptive study in which the prevalence of all cancers in the pedigrees of BRCA1- and BRCA2-mutation-positive groups and a group of families without mutations in either gene were compared with the general population. RESULTS: As expected, female breast and ovarian cancer was significantly increased in all three groups. Furthermore, male breast cancer was significantly elevated in the BRCA2-positive and BRCA-negative groups. Stomach cancer prevalence was significantly elevated in the BRCA2-positive families compared with the general population. CONCLUSIONS: These results can be applied in estimation of cancer risks and may contribute to more comprehensive counselling of mutation-positive Caucasian breast and / or ovarian cancer families

"After years in the wilderness" : the discourse of land claims in the new South Africa

The paper examines land restitution in the new South Africa, and looks at the intersecting roles of land-claiming communities who were forcibly resettled from their land during the apartheid years and the NGOs and – since 1994 - Government Commissioners who have helped them to reclaim the land. Ideas and practices concerning land, community and development that have emerged from the interaction between these different players have been mutually constitutive but are sometimes mutually incomprehensible. A populist rhetoric, evident both in discussions with former land owners, and in much of the writing in NGO publications such as Land Update, depicts land as something communally owned which must be communally defended. This sense of a uniformly experienced injustice and a shared resistance against outside intervention obscures the fact that claims on land derive from a series of sharply differentiated historical experiences and articulate widely divergent interests, such as those - in the case of the farm Doornkop for example - between former owners and their former tenants. The restitution of land to these former owners, while being of great importance to them as a source of identity and as a redress of past injustices, is not necessarily the key to solving “poverty, injustice and misery” as has been claimed for the process of land reform as a whole