“Ndiyindoda” [I am a man]: theorising Xhosa masculinity

Masculinity studies in South Africa depend on Western gender theories to frame research questions and fieldwork. This article argues that such theories offer a limited understanding of Xhosa constructions of masculinity. Xhosa notions of masculinity are embodied in the concept of indoda, meaning a traditionally circumcised person. This article explores the nuanced meanings of indoda and its relationship to other masculinities, like uncircumcised boys [inkwenkwe] and medically circumcised men. The discussion reveals that indoda is the most “honoured” form of masculinity. A traditionally circumcised individual is regarded as indoda, a real man, irrespective of his sexual orientation or class, and this affords him certain rights and privileges. Inkwenkwe and medically circumcised men embody “subordinate” forms of masculinity and are victims of stigma and discrimination by indoda. This requires us to revisit some Western theories of masculinity which place heterosexual men at the top of a masculine hierarchy and gay men at the bottom. It furthermore requires us to pay attention to the body when theorising Xhosa masculinity, since it is a principal way of “proving” and “defending” Xhosa manhood.IBS

Meta-analysis of type 2 Diabetes in African Americans Consortium

Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

Flow visualization in a low-density plasma channel

A schlieren system and surface-stress-sensitive film system were developed for a plasma channel which posed unique challenges for flow visualization because of the combination of low air density and the presence of plasma discharges. Temperature-sensitive paint and direct-current discharge were also applied to flow visualization. Three pulsed schlieren light sources were evaluated. A light-emitting diode (LED), a xenon NanopulserTM and laser breakdown, were tested on identical flowfields. The LED provided excellent illumination, with pulses ranging from μs to continuous. The NanopulserT

Crowd Flow Characterization with Optimal Control Theory

International audienceAnalyzing the crowd dynamics from video sequences is an open challenge in computer vision. Under a high crowd density assumption, we characterize the dynamics of the crowd flow by two related information: velocity and a disturbance potential which accounts for several elements likely to disturb the flow (the density of pedestrians, their interactions with the flow and the environment). The aim of this paper to simultaneously estimate from a sequence of crowded images those two quantities. While the velocity of the flow can be observed directly from the images with traditional techniques, this disturbance potential is far more trickier to estimate. We propose here to couple, through optimal control theory, a dynamical crowd evolution model with observations from the image sequence in order to estimate at the same time those two quantities from a video sequence. For this purpose, we derive a new and original continuum formulation of the crowd dynamics which appears to be well adapted to dense crowd video sequences. We demonstrate the efficiency of our approach on both synthetic and real crowd videos