Food aid and international hunger crises: The United States in Somalia

International food aid has long been known to be motivated by domestic and foreign policy objectives as well as humanitarian concerns. The policy objectives sometimes complicate delivery of emergency food, and lead to situations that result in adverse effects on the economic and agricultural systems of recipient countries. Despite the long history and extensive documentation of such effects, they were observed to occur once again during the 1992 Somalia intervention. This intervention encountered many frequently described barriers to effective use of emergency food aid. It also set a new precedent; for the first time, troops were deployed to enforce the safe delivery of food. This action led to the creation of an army of occupation engaged in military conflict with the very people it had come to serve and, eventually, to further deterioration of the country's food economy. The Somalia intervention provided further evidence for the need to uncouple humanitarian food aid from other policy objectives, and to design and manage emergency and long-term food aid programs to maximize benefits, minimize adverse consequences, and strengthen local agricultural production and marketing systems.     

Elephant-induced structural changes in the vegetation and habitat selection by large herbivores in an African savanna

African elephants can affect the quality of the habitat of other species by breaking or uprooting trees and shrubs in savannas. Their effect on vegetation has been widely studied but less is known about the effects of such vegetation changes on other animals. We studied how changes in the vegetation caused by elephants influence the selection of microhabitats by five African herbivore species (giraffe, kudu, steenbok, impala, and zebra) in Hwange National Park, Zimbabwe. There was no clear significant effect of overall elephant-induced vegetation changes on microhabitat selection except for the small species (steenbok and impala) that used vegetation modified by elephants preferentially. This is consistent with a medium-term browsing facilitation hypothesis. More subtle possible effects were detected for larger browsers (giraffe and kudu). They selected areas with broken and uprooted plants and avoided coppiced areas. All of the browsers selected sites characterized by plants uprooted and broken by elephants, which were associated with a higher visibility, and ultimately a better probability of detecting an approaching predator, suggesting that perceived predation risk plays an important role in microhabitat selection. These results illustrate how elephants can initiate indirect effects that influence microhabitat selection by other herbivores. Understanding the indirect effects of elephants through changes in food availability and predation risk thus needs further investigation. The results of this study do not provide support for the hypothesis that elephant-induced changes in the structure of habitats have caused the declines in the populations of the other herbivores in the study area.     

The effect of extreme HCL deposition on soil acid neutralization following simulated shuttle rocket launches

This study evaluated the effect of extreme HCl deposition on soil acid neutralization following simulated shuttle rocket launches. Four soils along a soil chronosequence from Vandenberg Air Force Base were selected and evaluated as a function of pH spike addition (pH=1.0, 2.5, 4.0, and 5.6) and time (0 to 4 mo) in a leaching-incubation experiment. The pH=1.0 treatment led to a rapid soil extract pH decrease to 2.5 in poorly buffered soils and increased leaching of basic cations (Ca, Mg, K, and Na), Al, and Si. In general, there were no significant differences among the pH= 2.5, 4.0, and 5.6 treatments. Acid neutralization capacity increased with increasing soil age. The acid neutralization process involved two steps. In Step 1, acid is neutralized by direct or indirect exchange with exchangeable basic cations. The most likely mechanisms for this step are: (1) the direct exchange of H′ for basic cations followed by an interchange reaction between surface H′ and structural Al, and (2) the indirect exchange through H⁺ neutralization by polyhydroxyl-Al complexes with concurrent base displacement. Acid neutralization by a gibbsite-like mineral is an unlikely mechanism controlling the initial acid neutralization step. Eventually a pure acidic (H-A l) complex develops. In Step 2, further acid neutralization is governed by mineral dissolution via the acidic cations (H′, All').     

Influence of Soil Type on the Effects of Elevated Atmospheric CO2 and N Deposition on the Water Balance and Growth of a Young Spruce and Beech Forest

Sixteen open-top chambers, each equipped with two non-weighablegravity-drained lysimeter compartments, were used to investigate the impacts of elevated atmospheric carbon dioxide (CO₂) concentration and nitrogen (N) deposition on the water relations and growth of young model forest ecosystems on two different types of soils. The same vegetation of a mixed spruce and beech overstorey and various herbs in the understorey was planted in all treatments on both soils. The soils were repacked on top of a drainage layer. Four combinations of treatments were applied in four replicates each: ambient (370 cm³ m^-3) CO₂ + low (7 kg N ha^-1 a^-1) N deposition, ambient CO₂ + high(70 kg N ha^-1 a^-1) N deposition, elevated (590 cm³ m^-3) CO₂ + low N deposition, and elevated CO₂ + high N deposition. After canopy closure, treatment effects on evapotranspiration and growth during the third year of study were very different for the two soils.On the acidic sandy loam, elevated CO₂ enhanced growth(leaf biomass +21%, roots +27%) at reduced evapotranspiration (–9%). High N deposition increased aboveground growth even more strongly (+50%), but also increased evapotranspiration (+16%). Together, elevated CO₂ and high N had a more than additive fertilizer effect on growth, while their effects on evapotranspirationcompensated. On the calcareous loamy sand, elevated CO₂not only tended to enhance growth (leaf biomass +17%, roots +20%), but also increased evapotranspiration (+5%).On this soil, aboveground growth was stimulated by N only incombination with elevated CO₂, but less than on the acidic soil, while evapotranspiration (–6.5%) and root growth into the subsoil (–54%) were decreased by increased N deposition at both CO₂ concentrations, in contrast to the N treatments on the acidic sandy loam. The influence of the soil on the observed ecosystem responses canbe interpreted in terms of the concept of optimal resource allocation.     

Posttransfusion viability of feline erythrocytes stored in acid-citrate-dextrose solution

The 24-hour posttransfusion viability of erythrocytes was determined in feline blood stored in acid-citrate-dextrose solution, using 51Cr-labeling. Viability decreased significantly (P less than 0.01) between 30 to 40 days of storage. It was concluded that feline blood can be stored in acid-citrate-dextrose solution at 4 C for at least 30 days and retain high erythrocyte viability.     

Interactions of aflatoxin and the antioxidant butylated hydroxytoluene in two-week-old chicks

Two-week dietary administration of 2500 ppb aflatoxin was sufficient to cause a decrease in bursal weights and a reduction in the number of splenic leukocytes in chicks. No significant effects on weight gain or feed efficiency were evident. The chicks also had elevated heterophil-to-lymphocyte ratios, suggesting a heightened reaction to stress. This effect could be blocked by dietary administration of the antioxidant butylated hydroxytoluene (BHT) at a concentration eight-fold over that normally present to preserve control feed. The BHT treatment increased the activities of the enzymes glutathione-S-transferase, aniline hydroxylase and O-demethylase, which metabolize aflatoxins in the liver.     

Tick- and flea-borne rickettsial emerging zoonoses

Between 1984 and 2004, nine more species or subspecies of spotted fever rickettsiae were identified as emerging agents of tick-borne rickettsioses throughout the world. Six of these species had first been isolated from ticks and later found to be pathogenic to humans. The most recent example is Rickettsia parkeri, recognized as a human pathogen more than 60 years after its initial isolation from ticks. A new spotted fever rickettsia, R. felis was also found to be associated with fleas and to be a human pathogen. Similarly, bacteria within the family Anaplasmataceae have been considered to be of veterinary importance only, yet three species have been implicated in human diseases in recent years, including Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis, Anaplasma phagocytophilum, the agent of human anaplasmosis (formerly known as "human granulocytic ehrlichiosis agent", E. equi and E. phagocytophila), and finally Ehrlichia ewingii, which causes granulocytic ehrlichiosis in humans. We present here an overview of the various tick- and flea-borne rickettsial zoonoses described in the last 20 years, focusing on the ecological, epidemiological and clinical aspects.     

Poultry, pig and the risk of BSE following the feed ban in France--a spatial analysis

A spatial analysis was carried out in order to analyse the reason why the risk of Bovine Spongiform Encephalopathy (BSE) was spatially heterogeneous in France, during the period following the feed ban of Meat and Bone Meal to cattle. The hypothesis of cross-contamination between cattle feedstuff and monogastric feedstuff, which was strongly suggested from previous investigations, was assessed, with the assumption that the higher the pig or poultry density is in a given area, the higher the risk of cross-contamination and cattle infection might be. The data concerned the 467 BSE cases born in France after the ban of meat and bone meal (July 1990) and detected between July 1st, 2001 and December 31, 2003, when the surveillance system was optimal and not spatially biased. The disease mapping models were elaborated with the Bayesian graphical modelling methods and based on a Poisson distribution with spatial smoothing (hierarchical approach) and covariates. The parameters were estimated by a Markov Chain Monte Carlo simulation method. The main result was that the poultry density did not significantly influence the risk of BSE whereas the pig density was significantly associated with an increase in the risk of 2.4% per 10 000 pigs. The areas with a significant pig effect were located in regions with a high pig density as well as a high ratio of pigs to cattle. Despite the absence of a global effect of poultry density on the BSE risk, some areas had a significant poultry effect and the risk was better explained in some others when considering both pig and poultry densities. These findings were in agreement with the hypothesis of cross-contamination, which could take place at the feedstuff factory, during the shipment of food or on the farm. Further studies are needed to more precisely explore how the cross-contamination happened.