While the relationship between socioeconomic status and child health has been studied extensively in developed countries, evidence is limited for developing countries. This study makes an important contribution by examining the relationship between child health and household socioeconomic status in Vietnam, using household expenditure as an alternative measure. This also allows us to explore the mechanisms via which income affects child health, in which household consumption arguably plays a crucial role. We employ different measures of health that allow us to examine both long-run and short-run effects, and two alternative instrumental variables, the unemployment rate and rainfall deviation, to address the potential endogeneity of household expenditure. We find evidence of a strong positive impact of household expenditure on child health and the findings are consistent across age groups. Specifically, a 10% increase in expenditure will result in a weight gain of 213–541 g in a “typical” child. We also explore the effect of a range of exogenous adverse economic shocks on children's health.

Research on producer willingness to adopt individual best pasture management practices (BMPs) is extensive, but less attention has been paid to producers simultaneously adopting multiple, complementary BMPs. Applications linking primary survey data on BMP adoption to water quality biophysical models are also limited. A choice-experiment survey of livestock producers is analyzed to determine willingness to adopt pasture BMPs. Sediment abatement curves are derived by linking estimates of producer responsiveness to incentives to adopt rotational grazing with a biophysical simulation model. Current cost share rates of $24/acre should yield a 12% decrease in sediment loading from pastures.

The study of colonizing and of dominant grass species is essential for prairie conservation efforts. We sought to answer how naturalized Kentucky bluegrass in the northern Great Plains has become successful in the last 20 yr despite its long history in the northern Great Plains. We tested for evidence of geographical differentiation using flow cytometry and microsatellite markers to ascertain the population genetics of Kentucky bluegrass. Across all tested wild populations, high levels of genetic diversity were detected along with moderate levels of structure. Mantel tests of geographical patterns were not significant. Using clonal assignment, we found two major clones that made up the majority of the tested wild populations. When we compared the wild individuals to pedigree cultivars, we found virtually no genetic overlap across all tests, which did not support our hypothesis of developed cultivars contributing to high genetic diversity in natural populations. Furthermore, DNA content tests indicated a narrow range in ploidy in wild populations compared with lawn cultivars, further supporting a hypothesis of divergence between wild and pedigree cultivars. These results indicate the recent invasion of Kentucky bluegrass in the northern Great Plains is not because of adaptation or propagule pressure, but rather likely an environmental or land use shift.

Using annual Japanese fresh fruit import data from 1971 to 1997, this study analyzes the import patterns of Japan's seven most popular fresh fruits by implementing and testing a general differential demand system that nests four alternative import demand specifications. When tested against the general system using the five-good case (bananas, grapefruits, oranges, and lemons and aggregating pineapples, berries, and grapes), the analysis rejects the Almost Ideal Demand System and National Bureau of Research specifications but does not reject Rotterdam and Central Bureau of Statistics models. When estimated using the six-good case (bananas, grapefruits, oranges, lemons, and pineapples and aggregating berries and grapes), the analysis rejects all specifications except the Rotterdam model.

International agricultural trade has evolved over time. Processed foods and developing countries have become major growth markets for U.S. agricultural exports, and foreign direct investment (FDI) has become even more important than exports as a means of accessing foreign markets. The critical question is whether FDI is a substitute for or a complement of exports. This research builds upon an existing theoretical FDI model and contributes to the literature through the development of a simultaneous equation system for FDI and exports, which is estimated using two-stage least squares. Empirical analyses were used to examine the relationship between U.S. FDI and exports of processed foods into East Asian countries-China, Japan, Singapore, South Korea, and Taiwan-from 1989 to 1998. The results indicated a complementary relationship between FDI and exports. Additionally, these results indicated that interest rates, exchange rates, gross domestic product (GDP), and compensation rates are important variables that influence U.S. FDI in East Asian countries, while GDP, exchange rates, and export prices are important export determinants.

A previous study showed that imposing economic restrictions improves the forecasting ability of food demand systems, thus warranting their use even when they are rejected in-sample. This article evaluates whether this result is due to economic restrictions enhancing degrees of freedom or containing nonsample information. Results indicate that restrictions improve forecasting ability even when they are not derived from economic theory, but theoretical restrictions forecast best.

The effects of population, income, prices of major inputs, and exchange rateof the U.S. dollar on the prices of three key agricultural and foodcommodities (feed grains, oilseed, and fruits) for 13 low-income countriesand seven middle-income countries were evaluated. Given the short timeperiod, a modified seeming unrelated regression-vector autoregressive modelthat incorporates the lagged exogenous variables property of time seriesmodels and the system of equation estimation is employed in the analysis.The study finds no single factor that persistently explains all soaring foodprices as reported in the literature. The only factor that persistentlyexplains soaring food prices are the contemporaneous and one-year laggedexchange rates and income.

We investigate the impact of receiving a public pension on total expenditures, food expenditures, and private transfers of the elderly in South Korea. Using a natural experiment that occurred in 1999, we are able to explore the impacts of a large public pension program expansion which newly incorporated people who had been self-employed, unemployed, and out of the labor force. We find that receipt of a public pension did not allow the elderly to increase total expenditures or food expenditures because the expansion of public pensions largely crowded out financial transfers from adult children and/or own siblings.

Unmanned Air Systems (UAS) navigate using Global Navigation Satellite Systems (GNSS), but GNSS vulnerability precludes its use as the only means of navigation and requires a secondary means of navigation. A differentiating characteristic of UAS is their periodic communications with the ground station. This paper analyses the adequacy of employing UAS Command, Control and Communications (C3) as a secondary means of navigation. With no additional infrastructure, an Extended Kalman Filter (EKF) is used to process C3 messages and to obtain the positions of the UAS. Navigation accuracy and integrity are calculated in a scenario with three UAS. The obtained results meet the International Civil Aviation Organization (ICAO) Performance-Based Navigation (PBN) requirements.

The spatially fixed sporophyte body of vascular land plants has to be adapted to both atmospheric and substrate environments. Potentially almost all stages in the life cycle of a land plant are fossilisable and the physiological adaptations to these environments are reflected in the morphology, anatomy, and chemistry of the plant. Although solutions to the plant's physiological problems have been refined through evolution, the basic responses to fundamental environmental parameters such as temperature, water availability, nutrient supply, gas exchange and light, evolved early in land plant history. These taxon-independent solutions can be used qualitatively, and sometimes quantitatively, to track changes in atmospheric and edaphic conditions throughout much of the Phanerozoic. Increase in body size and height in Middle and Late Devonian times was coupled with intense demand for light, nutrients and water supply and with elaborations of vascular systems, photosynthetic surfaces, organ abscission and ‘root’ organisation. During the Carboniferous extreme adaptations to substrate waterlogging evolved. Mycorrhizal associations and “phi” layers in Triassic roots represent early aspects of modern root physiology. From the mid-Cretaceous, angiosperms exhibit leaf architectural characteristics which in modern plants relate qualitatively to moisture and light, and quantitatively to temperature, while vessel size and distribution in trunk wood is related to water stress and susceptibility to freezing. The relative proportion of plants utilising C3, CAM, and C4 photosynthetic pathways varies with environment. Isotopic analysis of plant fossils may demonstrate changing relative frequencies of photosynthetic pathways through time in relation to atmospheric composition and temperature.