Food security in the Sahel: variable import levy, grain reserves, and foreign exchange assistance
In: Research report / International Food Policy Research Institute, 26
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In: Research report / International Food Policy Research Institute, 26
World Affairs Online
"The book recounts the history and achievements of research at the International Livestock Research Institute (ILRI), including work at its predecessors the International Livestock Centre for Africa (ILCA; 1974-1994) and the International Laboratory for Research on Animal Diseases (ILRAD; 1974-1994)"--
In: World Bank regional and sectoral studies
Examines fertilizer use in sub-saharan Africa, fertilizer response and economic returns and fertilizer subsidies with government budgetary constraints. Estimates fertilizer import demand.
BASE
In: Economic Development and Cultural Change, Band 36, Heft 1, S. 73-99
ISSN: 1539-2988
In: Economic development and cultural change: a journal designed for exploratory discussion of the problems of economic development and cultural change. Supplement
ISSN: 0013-0079
Der Analyse zugrundegelegt werden die heute noch in vielen Teilen Afrikas südlich der Sahara anzutreffenden Gegebenheiten eines relativen Überflusses an Land, einfacher Bodenbearbeitungsmethoden und hoher Transportkosten. Nach einer Beschreibung der wesentlichen Charakteristika eines solchen Subsistenzsystems werden Vorhersagen gemacht, welche institutionellen und strukturellen Veränderungen zu erwarten sind als Reaktion auf sich erhöhende Bevölkerungsdichten und auf die Öffnung subsistenzorientierter Gemeinschaften durch externe Migration und interregionalen oder internationalen Handel. (DÜI-Hlb)
World Affairs Online
In: The Journal of sex research, Band 12, Heft 2, S. 135-146
ISSN: 1559-8519
A single session of anodal transcranial direct current stimulation (tDCS) has been shown to increase arousal in healthy participants for up to 24 h post-stimulation. However, little is known about the effects of tDCS on subsequent sleep in this population. Based on previous clinical studies, we hypothesized that anodal stimulation to the left dorsolateral prefrontal cortex (lDLPFC) would produce higher arousal with decreased sleep time and stimulation to the primary motor cortex (M1) would have the converse effect. Thirty-six active duty military were randomized into one of three groups (n = 12/group); active anodal tDCS over the lDLPFC, active anodal tDCS over left M1, or sham tDCS. Participants answered questionnaires 3 times a day and wore a wrist activity monitor (WAM) to measure sleep time and efficiency for 3 weeks. On weeks 2 and 3 (order counterbalance), participants received stimulation at 1800 h before 26 h of sustained wakefulness testing (sleep deprived) and at 1800 h without sleep deprivation (non-sleep deprived). There were no significant effects for the non-sleep deprived portion of testing. For the sleep deprived portion of testing, there were main effects of group and night on sleep time. The DLPFC group slept less than the other groups on the second and third night following stimulation. There is no negative effect on mood or sleep quality from a single dose of tDCS when participants have normal sleep patterns (i.e., non-sleep deprived portion of testing). The results suggest that stimulation may result in faster recovery from fatigue caused by acute periods of sleep deprivation, as their recovery sleep periods were less.
BASE
In: Human factors: the journal of the Human Factors Society, Band 52, Heft 1, S. 41-53
ISSN: 1547-8181
Objectives: We evaluate visual search performance in both static (nonmoving) and dynamic (moving) search environments with and without spatial (3-D) auditory cues to target location. Additionally, the effects of target trajectory, target location, and practice are assessed. Background: Previous research on aurally aided visual search has shown a significant reduction in response times when 3-D auditory cues are displayed, relative to unaided search. However, the vast majority of this research has examined only searches for static targets in static visual environments. The present experiment was conducted to examine the effect of dynamic stimuli upon aurally aided visual search performance. Method: The 8 participants conducted repeated searches for a single visual target hidden among 15 distracting stimuli. The four main conditions of the experiment consisted of the four possible combinations of 3-D auditory cues (present or absent) and search environment (static or dynamic). Results: The auditory cues were comparably effective at reducing search times in dynamic environments (—25%) as in static environments (—22%). Audio cues helped all participants. The cues were most beneficial when the target appeared at large eccentricities and on the horizontal plane. After a brief initial exposure to 3-D audio, no training or practice effects with 3-D audio were found. Conclusion: We conclude that 3-D audio is as beneficial in environments comprising moving stimuli as in those comprising static stimuli. Application: Operators in dynamic environments, such as aircraft cockpits, ground vehicles, and command-and-control centers, could benefit greatly from 3-D auditory technology when searching their environments for visual targets or other time-critical information.
World Affairs Online
In: World development: the multi-disciplinary international journal devoted to the study and promotion of world development, Band 84, S. 55-68
In: Studies in comparative international development: SCID, Band 27, Heft 1, S. 81-101
ISSN: 1936-6167