Yang-Mills- and D-instantons

In these lectures, which are written at an elementary and pedagogical level, we discuss general aspects of (single) instantons in SU(N_c) Yang-Mills theory, and then specialize to the case of N = 4 supersymmetry and the large N_c limit. We show how to determine the measure of collective coordinates and compute instanton corrections to certain correlation functions. We then relate this to D-instantons in type IIB supergravity. By taking the D-instantons to live in an $AdS_5\times S^5$ background, we perform explicit checks of the AdS/CFT correspondence.Comment: 62 pages, typos corrected, table of contents and references adde

Human Performance During a Short- and a Long-Term Stay in Space

During short- and long-term space missions cosmonauts are exposed to several physical, mental, and emotional stressors (e.g., microgra- vity, enhanced noise levels, disturbed sleep, confinement, reduced social contacts) which may impair their performance capabilities. To analyze the impact of the space environment on cognitive, visuo- motor, and time-sharing performance a (1) German cosmonaut was as- sessed repeatedly during a short-term (8 days) space flight, and (2) a Russian cosmonaut was assessed during the first four month of his long-term (14 months) stay onboard MIR station. A subset of tasks of the AGARD battery of Standardized Tests for Research with Environmental Stressors (STRES, AGARD, 1989) was used for that purpose. Cognitive performance was probed by a Grammatical Reasoning Task and two versions of a Sternberg Memory Search Task differing in memory load. Fine manual control performance was assessed by an Unstable Tracking Task. Time-sharing performance was analyzed by dual-task combinationsof Unstable Tracking with concurrent Memory Search. During the long-term single case study the subjective workload of the cosmonaut experienced during task performance was assessed by the NASA Task Load Index (TXL). Results: Whereas basic cognitive operations (memory search, logical reasoning) were almost unimpaired, significant decrements of visuo-motor performance (tracking) occured in both studies. Recovery was found immediately back on Earth (first study), and after approximately three weeks in space (second study). Subjective effort ratings as well as ratings of mental and physical task demands were elevated for the first two weeks onboard MIR. After this initial period of adaptation, performance in all tasks and all subjective workload ratings returned to pre-flight baseline level and remained fairly stable for the following weeks in space

Language abstraction, intergroup bias and national essentialism

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Does linguistic abstractness influence intergroup bias? Experimental study in four European countries

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