University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Visualization. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

On the ultrasonic attenuation in glasses at low temperatures

Abstract: The ultrasonic attenuation in glasses at low temperatures is calculated using the model proposed by Anderson, Halperin, and Varma It is found that the resonant absorption of sound by the localized two-level systems saturates and can be observed only if the sound amplitude is extremely small A second contribution to the sound absorption is derived which arises from the relaxation of the localized excitations and does not saturate Qualitative agreement with recent measurements of the ultrasonic attenuation in fused silica is obtained

Rapid evolution revealed by dormant eggs

Abstract: Natural selection can lead to rapid changes in organisms, which can in turn influence ecosystem processes1 A key factor in the functioning of lake ecosystems is the rate at which primary producers are eaten, and major consumers, such as the zooplankton Daphnia2, can be subject to strong selection pressures when phytoplankton assemblages change Lake Constance in central Europe experienced a period of eutrophication (the biological effects of an input of plant nutrients) during the 1960s–70s3, which caused an increase4 in the abundance of nutritionally poor or even toxic5 cyanobacteria By hatching long-dormant eggs6 of Daphnia galeata found in lake sediments, we show that the mean resistance of Daphnia genotypes to dietary cyanobacteria increased significantly during this eutrophication This rapid evolution of resistance has implications for the ways that ecosystems respond to nutrient enrichment through the impact of grazers on primary production

Event related potentials to emotional adjectives during reading.

Abstract: We investigated to what extent emotional connotation influences cortical potentials during reading. To this end, event-related potentials (ERPs) were recorded during reading of high arousal pleasant and unpleasant and low arousal neutral adjectives that were presented at rates of 1 Hz and 3 Hz. Enhanced processing of both pleasant and unpleasant emotional compared to neutral adjectives was first reflected in an amplified early posterior negativity (EPN) starting from 200 ms after word onset. Later potentials (>300 ms), as analyzed in the slower 1 Hz condition, revealed facilitated processing selectively for pleasant adjectives that were associated with a reduced N400 and an enhanced late positive potential (LPP). Pleasant adjectives were also better remembered in an incidental memory test. Thus, emotionally relevant adjectives are processed spontaneously and selectively. Initially, emotional arousal drives attention capture (EPN). Healthy subjects may have a natural bias toward pleasant information facilitating late ERPs (N400, LPP) to pleasant adjectives as well as their superior recall.

Ochratoxin A: the continuing enigma.

Abstract: The mycotoxin ochratoxin A (OTA) has been linked to the genesis of several disease states in both animals and humans It has been described as nephrotoxic, carcinogenic, teratogenic, immunotoxic, and hepatotoxic in laboratory and domestic animals, as well as being thought to be the probable causal agent in the development of nephropathies (Balkan Endemic Nephropathy, BEN and Chronic Interstitial Nephropathy, CIN) and urothelial tumors in humans As a result, several international agencies are currently attempting to define safe legal limits for OTA concentration in foodstuffs (eg, grain, meat, wine, and coffee), in processed foods, and in animal fodder In order to achieve this goal, an accurate risk assessment of OTA toxicity including mechanistic and epidemiological studies must be carried out Ochratoxin has been suggested by various researchers to mediate its toxic effects via induction of apoptosis, disruption of mitochondrial respiration and/or the cytoskeleton, or, indeed, via the generation of DNA adducts Thus, it is still unclear if the predominant mechanism is of a genotoxic or an epigenetic nature One aspect that is clear, however, is that the toxicity of OTA is subject to and characterized by large species- and sex-specific differences, as well as an apparently strict structure-activity relationship These considerations could be crucial in the investigation of OTA-mediated toxicity Furthermore, the use of appropriate in vivo and in vitro model systems appears to be vital in the generation of relevant experimental data The intention of this review is to collate and discuss the currently available data on OTA-mediated toxicity with particular focus on their relevance for the in vivo situation, and also to suggest possible future strategies for unlocking the secrets of ochratoxin A