The relationship between higher-order cognition and personality.

A latent variable approach was used to (1) examine the relationship between working memory capacity and fluid intelligence, (2) compare the relationship between fluid intelligence and two measures of working memory capacity (complex span and n-back), (3) identify higher-order personality factors and (4) determine the relationship between higher-order personality factors, working memory capacity and fluid intelligence. Confirmatory factor analysis followed by structural equation modeling described the complex span and n-back as highly correlated yet distinct constructs. Consistent with previous research, both measures correlated highly with fluid intelligence. Four higher-order personality factors best modeled the structure of personality. Moreover, these four factors had differential relationship to cognitive constructs. The current research provides a deeper understanding of the relationship between working memory capacity and fluid intelligence, including discrepancies considering the magnitude of the relationship between two types of working memory measures and fluid intelligence, and finally, the influence of a diverse personality structure on working memory capacity and fluid intelligence. Importantly, the study examined these relationships on a broad scale using multiple tasks at a latent level contributing to better understanding of the nature of working memory capacity - fluid intelligence relationship and the influence of personality on higher-order cognition.Ph.D.Committee Chair: Engle, Randall, W

Methylphenidate during early consolidation affects long-term associative memory retrieval depending on baseline catecholamines

RATIONALE: Synaptic memory consolidation is thought to rely on catecholaminergic signaling. Eventually, it is followed by systems consolidation, which embeds memories in a neocortical network. Although this sequence was demonstrated in rodents, it is unclear how catecholamines affect memory consolidation in humans. OBJECTIVES: Here, we tested the effects of catecholaminergic modulation on synaptic and subsequent systems consolidation. We expected enhanced memory performance and increased neocortical engagement during delayed retrieval. Additionally, we tested if this effect was modulated by individual differences in a cognitive proxy measure of baseline catecholamine synthesis capacity. METHODS: Fifty-three healthy males underwent a between-subjects, double-blind, placebo-controlled procedure across 2 days. On day 1, subjects studied and retrieved object-location associations and received 20 mg of methylphenidate or placebo. Drug intake was timed so that methylphenidate was expected to affect early consolidation but not encoding or retrieval. Memory was tested again while subjects were scanned three days later. RESULTS: Methylphenidate did not facilitate memory performance, and there was no significant group difference in activation during delayed retrieval. However, memory representations differed between groups depending on baseline catecholamines. The placebo group showed increased activation in occipito-temporal regions but decreased connectivity with the hippocampus, associated with lower baseline catecholamine synthesis capacity. The methylphenidate group showed stronger activation in the postcentral gyrus, associated with higher baseline catecholamine synthesis capacity. CONCLUSIONS: Altogether, methylphenidate during early consolidation did not foster long-term memory performance, but it affected retrieval-related neural processes depending on individual levels of baseline catecholamines

Protection of lakes and lakelands: problems, processes, perspectives

Mosaic structure ('patch' spatial pattern) and processes (nutrient and organic matter transport and removal, exchange of organisms) in postglacial lakeland areas (Northern and Eastern Poland) were evaluated. The importance of the lake-river systems, forest islands, wetlands and ecotones (transition zones between ecosystems) in these processes was underlined as well as in sustaining by them the biological and landscape diversity. The main endangerings connected with human impact, agricultural management, forest fragmentation, water pollution and global warming were indicated. Selected results of the former national and European research projects performed in lakeland areas were mentioned. The general guidelines for landscape management around the lakes were formulated e.g. appropriate patch composition, arrangement of protection zones with restoration of wetland, permanent biomonitoring and establishment of natural reserves as components of the European system NATURA 2000

Employee competence in a learning organization

The study shows the model of a learning organization as exemplified by a small business. In this kind of organization human resources are the key success factors and the "driving force" for intellectual and developmental potential that makes companies more creative and open to new ways of thinking about running and managing a business. This report shows that even micro and small enterprises can operate successfully successful on the market when they invest in knowledge development

Nutrient dynamics and retention in land/water ecotones of lowland, temperate lakes, and rivers /

"Reprinted from Hydrobiologia, vol. 251 (1993)."Includes bibliographical references.Herkomst: WE11

Properties of natural microlayers on Australian freshwater storages and their potential to interact with artificial monolayers

Microlayers are natural surface films derived from hydrophobic organic compounds that form on most lakes and streams. Holoarctic brown water lakes have been most commonly studied, with Australian research limited to marine microlayers. Artificial monolayers based on long-chain fatty alcohols have been applied to freshwater storages to reduce evaporative loss. As a water conservation strategy, monolayer technology was not widely adopted due to variable field performance. However, the role of natural microlayers in reducing monolayer performance has not previously been investigated. In this study, microlayer and subsurface samples from six water storages in Queensland were characterized for water quality indices including biochemical oxygen demand, permanganate index and ultraviolet light absorbance. Microlayer enrichment in southeast Queensland is comparable to or higher than holoarctic lakes. Results indicate that microlayer compounds have the potential to disrupt monolayers in at least three ways: As substrates for microbes capable of degrading monolayer compounds, as chromophores accelerating photodegradation, and as impurities disrupting the molecular packing required to reduce evaporative loss. The knowledge gained from studying natural microlayers can also be used to benchmark novel monolayer compounds, to minimize their environmental impact on freshwater ecosystems