Suchergebnisse

Village economies and peasant households represent the main link between the economy and the environment in sub-Saharan Africa. The links from the macro level and down to the household level and further to the natural resource base are complex. It may therefore be difficult to predict the impact of macro policies and external shocks on the environment. This paper presents a typology of village economies and village economy-wide models. The framework is applied to a special case where a model is proposed and estimated to examine the impacts of external shocks, including structural adjustment policies, on cash-crop production and chitemene (shifting cultivation) in a remote Zambian village characterized by a missing (or negligible) labour market, input supply constraints, and credit rationing. Our findings indicate that structural adjustment policies, by decreasing the profitability of maize production, may encourage households to increase their chitemene production, resulting in more rapid deforestation.

This case series describes findings from the clinical evaluation of US government personnel reporting symptoms after exposure to directional audible and sensory phenomena during their postings in Havana, Cuba, and their clinical outcomes after rehabilitation.

IMPORTANCE: United States government personnel experienced potential exposures to uncharacterized directional phenomena while serving in Havana, Cuba, from late 2016 through May 2018. The underlying neuroanatomical findings have not been described. OBJECTIVE: To examine potential differences in brain tissue volume, microstructure, and functional connectivity in government personnel compared with individuals not exposed to directional phenomena. DESIGN, SETTING, AND PARTICIPANTS: Forty government personnel (patients) who were potentially exposed and experienced neurological symptoms underwent evaluation at a US academic medical center from August 21, 2017, to June 8, 2018, including advanced structural and functional magnetic resonance imaging analytics. Findings were compared with imaging findings of 48 demographically similar healthy controls. EXPOSURES: Potential exposure to uncharacterized directional phenomena of unknown etiology, manifesting as pressure, vibration, or sound. MAIN OUTCOMES AND MEASURES: Potential imaging-based differences between patients and controls with regard to (1) white matter and gray matter total and regional brain volumes, (2) cerebellar tissue microstructure metrics (eg, mean diffusivity), and (3) functional connectivity in the visuospatial, auditory, and executive control subnetworks. RESULTS: Imaging studies were completed for 40 patients (mean age, 40.4 years; 23 [57.5%] men; imaging performed a median of 188 [range, 4-403] days after initial exposure) and 48 controls (mean age, 37.6 years; 33 [68.8%] men). Mean whole brain white matter volume was significantly smaller in patients compared with controls (patients: 542.22 cm(3); controls: 569.61 cm(3); difference, −27.39 [95% CI, −37.93 to −16.84] cm(3); P < .001), with no significant difference in the whole brain gray matter volume (patients: 698.55 cm(3); controls: 691.83 cm(3); difference, 6.72 [95% CI, −4.83 to 18.27] cm(3); P = .25). Among patients compared with controls, there were significantly greater ventral ...