Nonlithographic epitaxial Sn_xGe_(1–x) dense nanowire arrays grown on Ge(001)

We have grown 1-µm-thick Sn_xGe_(1–x)/Ge(001) epitaxial films with 0 < x < 0.085 by molecular-beam epitaxy. These films evolve during growth into a dense array of Sn_xGe_(1–x) nanowires oriented along [001], as confirmed by composition contrast observed in scanning transmission electron microscopy in planar view. The Sn-rich regions in these films dominate optical absorption at low energy; phase-separated Sn_xGe_(1–x) alloys have a lower-energy band gap than homogeneous alloys with the same average Sn composition

Temperature‐dependent transmission extended electron energy‐loss fine structure of aluminum

Inelastic electron scattering experiments in a transmission electron microscope provide a probe of core electron excitations that have binding energies below 2 keV, and that are localized within submicron diameter sample volumes. Extended electron energy‐loss fine‐structure measurements which show the variation with temperature of the mean squared relative displacement of aluminum yield a localized measurement of the Debye temperature which is in excellent agreement with macroscopic measurements

Ordinal Welfare Comparisons with Multiple Discrete Indicators: A First Order Dominance Approach and Application to Child Poverty

We develop an ordinal method for making welfare comparisons between populations with multidimensional discrete well-being indicators observed at the micro level. The approach assumes that, for each well-being indicator, the levels can be ranked from worse to better; however, no assumptions are made about relative importance of any dimension nor about complementarity/substitutability relationships between dimensions. The method is based on the concept of multidimensional first order dominance. We introduce a rapid and reliable algorithm for empirically determining whether one population dominates another on the basis of available binary indicators by drawing upon linear programming theory. These approaches are applied to household survey data from Vietnam and Mozambique with a focus on child poverty comparisons over time and between regions.

Effects of food price shocks on child malnutrition: The Mozambican experience 2008/09

A propitiously timed household survey carried out in Mozambique over the period 2008-09 permits us to evaluate the short-to-medium run relationship between sudden shocks to food prices and child nutrition status. We link local price inflation with child malnutrition status. We find that the prevalence of underweight amongst children rises in response to a higher inflation rate for basic food products. Stunting and wasting malnutrition measures are mostly insensitive to the inflation rate. The very high food inflation during 2008/09 was responsible for an extra 39,000 moderately underweight and 24,000 severely underweight children

Effects of food price shocks on child malnutrition:The Mozambican experience 2008/2009

AbstractA propitiously timed household survey carried out in Mozambique over the period 2008/2009 permits us to study the relationship between shifts in food prices and child nutrition status in a low income setting. We focus on weight-for-height and weight-for-age in different survey quarters characterized by very different food price inflation rates. Using propensity score matching techniques, we find that these nutrition measures, which are sensitive in the short run, improve significantly in the fourth quarter of the survey, when the inflation rate for basic food products is low, compared to the first semester or three quarters, when food price inflation was generally high. The prevalence of underweight, in particular, falls by about 40 percent. We conclude that the best available evidence points to food penury, driven by the food and fuel price crisis combined with a short agricultural production year, as substantially increasing malnutrition amongst under-five children in Mozambique

Solution-Phase Synthesis of Heteroatom-Substituted Carbon Scaffolds for Hydrogen Storage

This paper reports a bottom-up solution-phase process for the preparation of pristine and heteroatom (boron, phosphorus, or nitrogen)-substituted carbon scaffolds that show good surface areas and enhanced hydrogen adsorption capacities and binding energies. The synthesis method involves heating chlorine-containing small organic molecules with metallic sodium at reflux in high-boiling solvents. For heteroatom incorporation, heteroatomic electrophiles are added to the reaction mixture. Under the reaction conditions, micrometer-sized graphitic sheets assembled by 3−5 nm-sized domains of graphene nanoflakes are formed, and when they are heteroatom-substituted, the heteroatoms are uniformly distributed. The substituted carbon scaffolds enriched with heteroatoms (boron ~7.3%, phosphorus ~8.1%, and nitrogen ~28.1%) had surface areas as high as 900 m^2 g^(−1) and enhanced reversible hydrogen physisorption capacities relative to pristine carbon scaffolds or common carbonaceous materials. In addition, the binding energies of the substituted carbon scaffolds, as measured by adsorption isotherms, were 8.6, 8.3, and 5.6 kJ mol^(−1) for the boron-, phosphorus-, and nitrogen-enriched carbon scaffolds, respectively

Advancing small area estimation

The poverty mapping methodology for estimating welfare rankings from small areas has proven to be useful in guiding allocation of government funds, regional planning, and general policy formulation. Nevertheless, poverty mapping also suffers from a series of by now well recognized shortcomings. We apply an approach based on first order dominance (FOD) to small area estimation. Five advantages to the FOD approach are highlighted. First, it can serve as a complement to, substitute for, and/or extension of the poverty mapping methodology. Second, it directly uses census data with a minimum of assumptions imposed. Third, the methodology is straightforward to implement and the concepts are intuitive. Fourth, the FOD approach is multi-dimensional allowing for a broader conception of poverty. Finally, FOD indicators can be chosen that relate directly to public expenditure priorities We apply the approach to census data from Mozambique for 1997 and 2007 and compare results with the poverty mapping methodology. We conclude that the FOD approach is well suited to small area estimation

Poverty mapping based on first order dominance with an example from Mozambique

We explore a novel first order dominance (FOD) approach to poverty mapping and compare its properties to small area estimation. The FOD approach uses census data directly; is straightforward to implement; is multidimensional allowing for a broad conception of welfare; and accounts rigorously for welfare distributions in both levels and trends. An application to Mozambique highlights the value of the approach, including its advantages in the monitoring and evaluation of public expenditures. We conclude that the FOD approach to poverty mapping constitutes a useful addition to the toolkit of policy analysts