SOCIAL IDENTITY AND MANIPULATIVE INTERHOUSEHOLD TRANSFERS AMONG EAST AFRICAN PASTORALISTS

We model interhousehold transfers between nomadic livestock herders as the state-dependent consequence of individuals' strategic interdependence resulting from the existence of multiple, opposing externalities. A public good security externality among individuals sharing a social (e.g., ethnic) identity in a potentially hostile environment creates incentives to band together. Self-interested interhousehold wealth transfers from wealthier herders to poorer ones may emerge endogenously within a limited wealth space as a means to motivate accompanying migration by the recipient. The distributional reach and size of the transfer are limited, however, by a resource appropriation externality related to the use of common property grazing lands. When this effect dominates, it can induce distributionally regressive transfers from ex ante poor households who want to relieve grazing pressures caused by larger herds. As compared to the extant literature on transfers, our model appears more consistent with the limited available empirical evidence on heterogeneous and changing transfers patterns among east African pastoralists.Agribusiness, D, O, Q18,

Perceptions of Risk within Pastoralist Households in Northern Kenya and Southern Ethiopia

Perceptions of risk may vary within households as well as across households and communities. In this paper, we take advantage of panel survey data collected quarterly over a period of 2 ½ years to see how perceptions of risk vary across individuals over time. The surveyed households are in pastoralist communities in Northern Kenya and Southern Ethiopia and the survey period coincides with a severe drought in this region and the beginning of the recovery. We identify the structural heterogeneity of the perceptions of risk of these individuals. Because of the nature of panel data, we can also test how the perceptions of risk are affected by shocks in previous periods. In particular, we ask how an individual's risk perceptions change when shocks happen to him or herself, to other members of his or her, family, or to members of his or her community. This allows us to ask how expectations adapt based on the things that are happening to others and allows us to look at issues of social networks and learning.Risk and Uncertainty,

BAYESIAN HERDERS: ASYMMETRIC UPDATING OF RAINFALL BELIEFS IN RESPONSE TO EXTERNAL FORECASTS

Temporal climate risk weighs heavily on many of the world's poor. Recent advances in model-based climate forecasting have expanded the range, timeliness and accuracy of forecasts available to decision-makers whose welfare depends on stochastic climate outcomes. There has consequently been considerable recent investment in improved climate forecasting for the developing world. Yet, in cultures that have long used indigenous climate forecasting methods, forecasts generated and disseminated by outsiders using unfamiliar methods may not readily gain the acceptance necessary to induce behavioral change. The value of model-based climate forecasts depends critically on the premise that forecast recipients actually use external forecast information to update their rainfall expectations. We test this premise using unique survey data from pastoralists and agropastoralists in southern Ethiopia and northern Kenya, specifying and estimating a model of herders updating seasonal rainfall beliefs. We find that those who receive and believe model-based seasonal climate forecasts indeed update their priors in the direction of the forecast received, assimilating optimistic forecasts more readily than pessimistic forecasts.Agribusiness, O1, D1, Q12,

Existence and equilibration of global weak solutions to finitely extensible nonlinear bead-spring chain models for dilute polymers

We show the existence of global-in-time weak solutions to a general class of coupled FENE-type bead-spring chain models that arise from the kinetic theory of dilute solutions of polymeric liquids with noninteracting polymer chains. The class of models involves the unsteady incompressible Navier-Stokes equations in a bounded domain in two or three space dimensions for the velocity and the pressure of the fluid, with an elastic extra-stress tensor appearing on the right-hand side in the momentum equation. The extra-stress tensor stems from the random movement of the polymer chains and is defined by the Kramers expression through the associated probability density function that satisfies a Fokker-Planck-type parabolic equation, a crucial feature of which is the presence of a center-of-mass diffusion term. We require no structural assumptions on the drag term in the Fokker-Planck equation; in particular, the drag term need not be corotational. With a square-integrable and divergence-free initial velocity datum for the Navier-Stokes equation and a nonnegative initial probability density function for the Fokker-Planck equation, which has finite relative entropy with respect to the Maxwellian of the model, we prove the existence of a global-in-time weak solution to the coupled Navier-Stokes-Fokker-Planck system. It is also shown that in the absence of a body force, the weak solution decays exponentially in time to the equilibrium solution, at a rate that is independent of the choice of the initial datum and of the centre-of-mass diffusion coefficient.Comment: 75 page

An algebraic interpretation of the Wheeler-DeWitt equation

We make a direct connection between the construction of three dimensional topological state sums from tensor categories and three dimensional quantum gravity by noting that the discrete version of the Wheeler-DeWitt equation is exactly the pentagon for the associator of the tensor category, the Biedenharn-Elliott identity. A crucial role is played by an asymptotic formula relating 6j-symbols to rotation matrices given by Edmonds.Comment: 10 pages, amstex, uses epsf.tex. New version has improved presentatio

Asymptotics of 4d spin foam models

We study the asymptotic properties of four-simplex amplitudes for various four-dimensional spin foam models. We investigate the semi-classical limit of the Ooguri, Euclidean and Lorentzian EPRL models using coherent states for the boundary data. For some classes of geometrical boundary data, the asymptotic formulae are given, in all three cases, by simple functions of the Regge action for the four-simplex geometry.Comment: 10 pages, Proceedings for the 2nd Corfu summer school and workshop on quantum gravity and quantum geometry, talk given by Winston J. Fairbair

Social Identity and Manipulative Interhousehold Transfers Among East African Pastoralists

We model interhousehold transfers between nomadic livestock herders as the state-dependent consequence of individuals\u27 strategic interdependence resulting from the existence of multiple, opposing externalities. A public good security externality among individuals sharing a social (e.g., ethnic) identity in a potentially hostile environment creates incentives to band together. Self-interested interhousehold wealth transfers from wealthier herders to poorer ones may emerge endogenously within a limited wealth space as a means to motivate accompanying migration by the recipient. The distributional reach and size of the transfer are limited, however, by a resource appropriation externality related to the use of common property grazing lands. When this effect dominates, it can induce distributionally regressive transfers from ex ante poor households who want to relieve grazing pressures caused by larger herds. As compared to the extant literature on transfers, our model appears more consistent with the limited available empirical evidence on heterogeneous and changing transfers\u27 patterns among east African pastoralists

Spatial distribution of energy deposited in nitrogen by electrons

The spatial distribution of the energy deposited by kilovolt electrons moving through gaseous molecular nitrogen was measured. The range of electrons of initial energy 300 eV to 5 keV was obtained and can be expressed by the formula R=K1+K2EA1−K3EA2, where R is the range, E is the initial energy of the electrons, and Ki,Ai are constants. The range, in this energy interval, is greater than that determined by previous measurements. A source of error, not previously discussed, is considered. The energy region (above 1 keV) where the simpler expression R=KEA holds is discussed. It is shown that this is the energy region where the energy and range dependence of the energy deposition curve can be removed and a normalized, characteristic energy deposition curve λ can be obtained. The efficiency of conversion of electron energy at 1 keV and 280 μ pressure to energy of photons at 3914 Å was measured to be (0.28±0.03) %.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69995/2/JCPSA6-64-2-743-1.pd

Understanding Declining Mobility and Interhousehold Transfers Among East African Pasoralists

We model interhousehold transfers between nomadic livestock herders as the state-dependent consequence of individuals\u27 strategic interdependence resulting from the existence of multiple, opposing externalities. A public good security externality among individuals sharing a social (e.g., ethnic) identity in a potentially hostile environment creates incentives to band together. Self-interested interhousehold wealth transfers from wealthier herders to poorer ones may emerge endogenously within a limited wealth space as a means to motivate accompanying migration by the recipient. The distributional reach and size of the transfer are limited, however, by a resource appropriation externality related to the use of common property grazing lands. When this effect dominates, it can induce transfers from households who want to relieve grazing pressures caused by others\u27 herds. Our model augments the extant literature on transfers, and is perhaps more consistent with the limited available empirical evidence on heterogeneous and changing transfers\u27 patterns among east African pastoralists. The core principles of our model possibly apply more broadly, for example to long-distance migrants or even among foot soldiers in street gangs

Understanding Declining Mobility and Interhousehold Transfers among East African Pastoralists

We model interhousehold transfers between nomadic livestock herders as the state-dependent consequence of individuals\u27 strategic interdependence resulting from the existence of multiple, opposing externalities. A public good security externality among individuals sharing a social (e.g., ethnic) identity in a potentially hostile environment creates incentives to band together. Self-interested interhousehold wealth transfers from wealthier herders to poorer ones may emerge endogenously within a limited wealth space as a means to motivate accompanying migration by the recipient. The distributional reach and size of the transfer are limited, however, by a resource appropriation externality related to the use of common property grazing lands. When this effect dominates, it can induce transfers from households who want to relieve grazing pressures caused by others\u27 herds. Our model augments the extant literature on transfers, and is perhaps more consistent with the limited available empirical evidence on heterogeneous and changing transfers - patterns among east African pastoralists. The core principles of our model possibly apply more broadly, for example to long-distance migrants or even among foot soldiers in street gangs