Selective Mortality or Growth after Childhood? What Really is Key to Understand the Puzzlingly Tall Adult Heights in Sub-Saharan Africa

Sub-Sahara African populations are tall relative to the extremely adverse disease environment and their low incomes. Selective mortality, which removes shorter individuals leaving taller individuals in the population, was proposed as an explanation. From heights of surviving and non-surviving children in Gambia, we estimate the size of the survivorship bias and find it to be too small to account for the tall adult heights observed in sub-Saharan Africa. We propose instead a different yet widely ignored explanation: African populations attain a tall adult stature, because they can make up a significant amount of the growth shortfall after age 5. This pattern is in striking contrast to other developing countries. Moreover, mortality rates are relatively low after age 5 adding further doubts about selective mortality.adult height, mortality, sub-Saharan Africa, catch-up growth

Towards an Objective Account of Nutrition and Health in Colonial Kenya: A Study of Stature in African Army Recruits and Civilians, 1880-1980

nutrition, health, anthropometrics, inequality, colonial, Kenya

Rheological properties of a dilute suspension of self-propelled particles

With a detail microscopic model for a self-propelled swimmer, we derive the rheological properties of a dilute suspension of such particles at small Peclet numbers. It is shown that, in addition to the Einstein's like contribution to the effective viscosity, that is proportional to the volume fraction of the swimmers, a contribution due to the activity of self-propelled particles influences the viscosity. As a result of the activity of swimmers, the effective viscosity would be a lower (higher) than the viscosity of the suspending medium when the particles are pushers (pullers). Such activity dependent contribution, will also results to a non-Newtonian behavior of the suspension in the form of normal stress differences

The Impact of On-chip Communication on Memory Technologies for Neuromorphic Systems

Emergent nanoscale non-volatile memory technologies with high integration density offer a promising solution to overcome the scalability limitations of CMOS-based neural networks architectures, by efficiently exhibiting the key principle of neural computation. Despite the potential improvements in computational costs, designing high-performance on-chip communication networks that support flexible, large-fanout connectivity remains as daunting task. In this paper, we elaborate on the communication requirements of large-scale neuromorphic designs, and point out the differences with the conventional network-on-chip architectures. We present existing approaches for on-chip neuromorphic routing networks, and discuss how new memory and integration technologies may help to alleviate the communication issues in constructing next-generation intelligent computing machines.Comment: 26 pages, 6 figures, Journal of Physics D: Applied Physics 201

Three-Point Functions in N=2 Higher-Spin Holography

The CP^N Kazama-Suzuki models with the non-linear chiral algebra SW_infinity[lambda] have been conjectured to be dual to the fully supersymmetric Prokushkin-Vasiliev theory of higher-spin gauge fields coupled to two massive N=2 multiplets on AdS_3. We perform a non-trivial check of this duality by computing three-point functions containing one higher-spin gauge field for arbitrary spin s and deformation parameter lambda from the bulk theory, and from the boundary using a free ghost system based on the linear sw_infinity[lambda] algebra. We find an exact match between the two computations. In the 't Hooft limit, the three-point functions only depend on the wedge subalgebra shs[lambda] and the results are equivalent for any theory with such a subalgebra. In the process we also find the emergence of N=2 superconformal symmetry near the AdS_3 boundary by computing holographic OPE's, consistently with a recent analysis of asymptotic symmetries of higher-spin supergravity.Comment: 40 pages; This work is based on the first author's MSc thesis, submitted to the Niels Bohr Institute, University of Copenhagen, in November 2012. v2: References added. v3: Minor typos fixe