Population and Environmental Correlates of Maize Yields in Mesoamerica: a Test of Boserup’s Hypothesis in the Milpa

Using a sample of 40 sources reporting milpa and mucuna-intercropped maize yields in Mesoamerica, we test Boserup’s (1965) prediction that fallow is reduced as a result of growing population density. We further examine direct and indirect effects of population density on yield. We find only mixed support for Boserupian intensification. Fallow periods decrease slightly with increasing population density in this sample, but the relationship is weak. Controlling for other covariates, fallow-unadjusted maize yields first rise then fall with population density. Fallow-adjusted maize yields peak at 390 kg/ha/yr for low population densities (8 persons / km2) and decline to around 280 kg/ha/yr for the highest population densities observed in our dataset. Fallow practices do not appear to mediate the relationship between population density and yield. The multi-level modeling methods we adopt allow for data clustering, accurate estimates of group-level variation, and they generate conditional predictions, all features essential to the comparative study of prehistoric and contemporary agricultural yields

The appearance of discretionary income: Influence on the prevalence of under- and over-nutrition

<p>Abstract</p> <p>Undernutrition – protein energy malnutrition or specific nutrient deficiencies – has been an inherent characteristic of impoverished populations throughout the world. Over-nutrition, obesity and nutrition imbalance is a current concern among those with rising though still insufficient incomes. We review data to suggest that the prevalence of these forms of malnutrition in populations is highly influenced by the rate of appearance of discretionary income.</p> <p>In developed countries, discretionary (alternatively "disposable") income refers to funds available after obligate payments (rent, heat, and the cost of getting to work) and payment for necessities (food and clothing). For families living at or below poverty, the last dollar earned is spent on these obligations. Undernutrition is common. By contrast, likelihood for obesity or imbalance increases with rising income when that last dollar is earned without certainty that it is available for discretionary spending. In the United States, neither under- nor over-nutrition is likely when new income is free and clear of debt or obligation. This occurs at approximately three times the poverty level.</p> <p>While income poverty and food insecurity affect <it>risk </it>for malnutrition rather than <it>outcome</it>, nutrition education programs that address issues of income and food support increase likelihood for adherence to recommendations.</p

Estado nutricional e fatores associados à estatura de crianças da Terra Indígena Guarita, Sul do Brasil Nutritional status and social determinants of child height in the Guarita Indigenous Territory, Southern Brazil

O estado nutricional de crianças menores de cinco anos e fatores associados à estatura foram estudados usando dados de um programa para controle da desnutrição e mortalidade na Terra Indígena Guarita, Rio Grande do Sul, Brasil, 2001/2002. Índices antropométricos foram calculados em escores-z da referência CDC/2000. Na primeira avaliação pelo programa, 34,7%, das crianças apresentavam baixa estatura, 12,9% baixo peso para idade, 4,2% baixo peso para estatura e 8,7% sobrepeso. Baixa estatura foi mais prevalente em meninos e maiores de um ano. Modelos de regressão linear múltipla sugerem que a altura foi, em média, menor quando a água para alimentação era de fonte/poço/rio (p = 0,046), não havia geladeira para conservar alimentos (p = 0,021), a mãe era menor de 16 anos ao nascimento do mais velho entre os filhos menores de cinco anos (p = 0,019) e analfabeta (p = 0,083). O destino dos dejetos evidenciou efeito apenas no modelo bruto. Não houve evidência de efeito do número de filhos menores de cinco anos. Políticas de inclusão social e provisão de recursos sociais e de saúde são potencialmente relevantes para a saúde e nutrição nessa população.<br>The nutritional status of under-five children and the association between social conditions and child stature were examined using data from the program to control malnutrition and mortality in the Guarita Indigenous Territory, southern Brazil, 2001-2002. Anthropometric indices were calculated in z-scores of the CDC 2000 reference. At entrance into the program, 34.7% of the children presented stunting, 12.9% low weight for age, 4.2% wasting, and 8.7% overweight. Stunting was most prevalent among boys and children older than one year. Multivariate linear regression showed that, on average, children were shorter when the drinking water was collected directly in the environment (p = 0.046), there was no refrigerator for food preservation (p = 0.021), maternal age was less than 16 years at the birth of the oldest child among the under-fives (p = 0.019), and the mother was illiterate (p = 0.083). Sewage facilities only had an effect on the unadjusted model. There was no evidence that the number of under-five children had an effect on stature. Social inclusion policies and health and social provision which takes these factors into account are potentially relevant for improving health and nutrition in this population

Body composition and physical fitness of undernourished South African rural primary school children

0.001), and with sit and reach (boys, B = 0.59, P = 0.03). CONCLUSION: In the present study in undernourished children, body composition was significantly related to physical fitness, but not always in the expected direction. It is therefore important to note that in this population, BMI should not be interpreted as a measure of fatness/overweight, but rather as an indicator of muscle mas