Search results for "Reference"
showing 10 items of 2491 documents
No effects of pulsed radio frequency electromagnetic fields on melatonin, cortisol, and selected markers of the immune system in man.
2001
There is growing public concern that radio frequency electromagnetic fields may have adverse biological effects. In the present study eight healthy male students were tested to see whether or not radio frequency electromagnetic fields as used in modern digital wireless telecommunication (GSM standard) have noticeable effects on salivary melatonin, cortisol, neopterin, and immunoglobulin A (sIgA) levels during and several hours after exposure. In a specifically designed, shielded experimental chamber, the circularly polarized electromagnetic field applied was transmitted by an antenna positioned 10 cm behind the head of upright sitting test persons. The carrier frequency of 900 MHz was pulse…
Classical electromagnetic radiation in noninertial reference frames
1991
Customarily electromagnetic radiation is defined with reference to some inertial laboratory frame. But such a definition is too narrow to be applicable to questions concerning accelerated observers,e.g. why an accelerated observer does not receive radiation from a co-accelerating charge. It is shown in this paper that a radiation concept introduced for inertial observers by Rohrlich and Teitelboim allows an extension to noninertial (accelerating and rotating) reference frames in a natural way. The generalized concept is explicitly dependent on the proper acceleration and the rotation of the observer’s laboratory frame. The case of radiation due to an accelerated point charge is treated in f…
The electromagnetic field of an accelerated charge in the proper reference frame of a noninertial observer
1989
The Lienard-Wiechert formulae for the electric and magnetic fields of an accelerated charge moving along an arbitrary world-line are generalized so that they can be applied by noninertial observers using accelerating and rotating reference frames. For this purpose, a relativistic coordinate-independent formalism suggested by DeFacio, Dennis and Eetzloff is extended to the description of all kinematical aspects required in the theory of the retarded fields of a point charge. The generalized Lienard-Wiechert formula is applied to a number of special situations, demonstrating that it allows a lucid and concise treatment of a number of subtle problems such as the role of the «relativity of acce…
The Contingent Negative Variation – An Electrophysiological Correlate of Temporal Processing or Reference Memory?
2014
Abstract In EEG research, the contingent negative variation (CNV) is considered to be strongly related to interval timing (e.g., Macar & Vidal, 2004 ; Macar, Vidal, & Casini, 1999). However, it is discussed controversially whether certain properties of the CNV (e.g., amplitude, peak latency and resolution) directly reflect the process of temporal accumulation or rather processes related to reference memory or decision stages in temporal information processing (van Rijn et al., 2011). This present study was designed in order to investigate the relationship between CNV mean amplitude, CNV resolution, and memory processes as well as processes of temporal accumulation. The task design aimed at …
Social Housing Conditions Modulate the Long-Lasting Increase in Cocaine Reward Induced by Intermittent Social Defeat
2019
Social defeat is considered the most representative animal model for studying the consequences of social stress. Intermittent social defeat (ISD) has proved to enhance the response to cocaine hedonic properties. In the present research, we evaluated if different social housing conditions, as housing with a familiar conspecific or with a female, exert a protective effect modulating the negative consequences of ISD as the increased sensitivity to cocaine and the induction of anxiety-like behavior. To achieve this objective, non-stressed or ISD OF1 male mice were divided into five different experimental groups according to their social environment: standard housing (four adult males per cage);…
Dorsal root ganglia neurite outgrowth measured as a function of changes in microelectrode array resistance
2017
Current research in prosthetic device design aims to mimic natural movements using a feedback system that connects to the patient's own nerves to control the device. The first step in using neurons to control motion is to make and maintain contact between neurons and the feedback sensors. Therefore, the goal of this project was to determine if changes in electrode resistance could be detected when a neuron extended a neurite to contact a sensor. Dorsal root ganglia (DRG) were harvested from chick embryos and cultured on a collagen-coated carbon nanotube microelectrode array for two days. The DRG were seeded along one side of the array so the processes extended across the array, contacting a…
Krāsu un emociju attiecības vizuālajā komunikācijā: dažādu vecumposmu salīdzinoša analīze
2017
Darba tēma ir ‘’Krāsu un emociju attiecības vizuālajā komunikācijā: dažādu vecumposmu salīdzinoša analīze’’. Pētījuma problēma: Vai dažāda vecuma cilvēkiem atšķiras krāsu un emociju uztvere? Mērķis ir noskaidrot kā krāsu un emociju saistība mainās dažāda vecuma cilvēkiem. Darba uzdevumi ir iepazīties ar teoriju, noskaidrot krāsu un emociju saistību atšķirību dažādiem vecumposmiem, izmantojot aptauju un eksperimentu, apkopot datus un izdarīt secinājumus. Teorijā izmantotas trīs teorijas: vizuālās komunikācijas teorija, ekoloģiskās valences teorija, krāsas un emocijas. Metodoloģijā izmantotas trīs metodes: aptauja, kontentanalīze un eksperiments. Apkopojot rezultātus redzams, ka vecuma atšķir…
First impression misleads emotion recognition
2019
Recognition of others' emotions is a key life ability that guides one's own choices and behavior, and it hinges on the recognition of others' facial cues. Independent studies indicate that facial appearance-based evaluations affect social behavior, but little is known about how facial appearance-based trustworthiness evaluations influence the recognition of specific emotions. We tested the hypothesis that first impressions based on facial appearance affect the recognition of basic emotions. A total of 150 participants completed a dynamic emotion recognition task. In a within-subjects design, the participants viewed videos of individuals with trustworthy-looking, neutral, or untrustworthy-lo…
On the importance of being flexible: early interrelations between affective flexibility, executive functions and anxiety symptoms in preschoolers
2020
When children are confronted with an emotional problem, affective flexibility mobilizes their cognitive and emotional resources to optimally address it. We investigated the contribution of executiv...
Preference, Rationality and Interindividual Variation: The Persisting Debate About Female Choice
2015
Contemporary research on sexual selection remains deeply influenced by the controversy between Charles Darwin and Alfred Russel Wallace about the true nature and importance of female choice. After briefly reviewing the main points of disagreement between the two famous evolutionists, I discuss some methodological issues relevant to the contemporary study of female choice. I first use some recent controversy about sexual selection in the Indian Peafowl, Pavo cristatus, to illustrate several recurring problems and shortcomings in the empirical study of female preference for male characters. I then address the empirical evidence for rationality in female choice, and discuss how the recently em…