Search results for "reference"
showing 10 items of 2491 documents
Facilitating Effect of Natural Frequencies: Size Does Not Matter
2009
The question of whether humans are able to work in a Bayesian way is currently a topic of substantial investigation. An important finding, reported by Gigerenzer and Hoffrage in 1995 is that Bayesian reasoning is facilitated when the information format corresponds to natural frequencies. The present concern was whether the facilitating effect of frequencies persists when natural frequencies relate to samples which are not convenient multiples of 10. 150 undergraduates participated as volunteers (42 men, 108 women; M age = 23 yr.). Analysis showed the effect of natural frequency formats was not dependent on size of reference class. Theoretical and practical implications are discussed.
Confabulation: damage to a specific inferior medial prefrontal system
2008
Confabulation, the pathological production of false memories, occurs following a variety of aetiologies involving the frontal lobes, and is frequently held to be underpinned by combined memory and executive deficits. However, the critical frontal regions and specific cognitive deficits involved are unclear. Studies in amnesic patients have associated confabulation with damage to the orbital and ventromedial prefrontal cortices. However, neuroimaging studies have associated memory-control processes which are assumed to underlie confabulation with the right lateral prefrontal cortex. We used a confabulation battery to investigate the occurrence and localisation of confabulation in an unselect…
Nonlinear analysis of continuous ECG during sleep II. Dynamical measures
2000
The hypothesis that cardiac rhythms are associated with chaotic dynamics implicating a healthy flexibility has motivated the investigation of continuous ECG with methods of nonlinear system theory. Sleep is known to be associated with modulations of the sympathetic and parasympathetic control of cardiac dynamics. Thus, the differentiation of ECG signals recorded during different sleep stages can serve to determine the usefulness of nonlinear measures in discriminating ECG states in general. For this purpose the following six nonlinear measures were implemented: correlation dimension D2, Lyapunov exponent L1. Kolmogorov entropy K2, as well as three measures derived from the analysis of unsta…
Nonlinear analysis of continuous ECG during sleep I. Reconstruction.
2000
In recent years evidence has accumulated that ECG signals are of a nonlinear nature. It has been recognized that strictly periodic cardiac rhythms are not accompanied by healthy conditions but, on the contrary, by pathological states. Therefore, the application of methods from nonlinear system theory for the analysis of ECG signals has gained increasing interest. Crucial for the application of nonlinear methods is the reconstruction (embedding) of the time series in a phase space with appropriate dimension. In this study continuous ECG signals of 12 healthy subjects recorded during different sleep stages were analysed. Proper embedding dimension was determined by application of two techniqu…
Electromyographic activity of the jaw muscles and mandibular kinematics in young adults with theoretically ideal dental occlusion: Reference values
2016
Background A necessary step to use neuromuscular analysis as diagnostic tool is to establish normal reference values for the physiological range in a healthy population. Surface electromyographic (sEMG) activity of the jaw muscles and mandibular kinematics were measured in young adults with theoretically ideal dental occlusion to determine normal reference values during different tasks. Differences between the sexes were evaluated. Material and Methods Forty young adults (20 men, 20 women; mean age 22.8 ± 3.9 years) with theoretically ideal dental occlusion were selected using very restrictive criteria. sEMG activity of the anterior temporalis (AT), posterior temporalis, masseter (MA), and …
Effects of combined hand-arm vibration and cold on skin temperature
1989
Under laboratory conditions 14 healthy male subjects were exposed to hand-arm vibration (ahzw = 6.3 m/s2) at different air temperatures (5 degrees, 12 degrees, 18 degrees and 25 degrees C). Static load (grip force 15 N, push force 40 N) was kept constant. Finger tip temperature as an indirect criterion of the peripheral blood circulation was measured. As expected, low air temperatures (5 degrees, 12 degrees and 18 degrees C) cause a strong decrease of skin temperature. Under additional stress of vibration connected with static load, a further decrease of the mean skin temperature was noted. At this, static load proved to have a predominant influence on the acute diminution of skin temperatu…
Color-coded duplex ultrasonography of the origin of the vertebral artery: normal values of flow velocities.
2000
The introduction of color-coded duplex ultrasonography has improved the ease of performing ultrasound investigations of the vertebral arteries. So far, normal values of flow velocities have been reported only for the intertransverse region of the vertebral artery (V2 segments). Atherosclerotic disease at the origin of the vertebral arteries (V0 segment) is frequent and is one of the risk factors for vertebrobasilar ischemic disease. Normal values of flow velocities of the vertebral artery origin are needed to assess pathologic findings, such as vertebral artery origin stenosis or dissection. The aim of this study was to describe the normal flow velocities of vertebral artery origin (V0 segm…
'Prefrontal' cognitive performance of healthy subjects positively correlates with cerebral FDOPA influx: an exploratory [18F]-fluoro-L-DOPA-PET inves…
2006
Dopamine neurotransmission influences those cognitive processes, which are generally regarded as prefrontal cortical functions. In previous positron‐emission‐tomography (PET) studies, net blood‐brain clearance of [(18)F]‐fluoro‐l‐DOPA (FDOPA) correlated with impaired cognitive performance in patients with Parkinson's disease or schizophrenia. We hypothesized that FDOPA influx also correlates with performance of cognitive tasks associated with prefrontal functioning in healthy volunteers. The net blood‐brain clearance of FDOPA (K [Formula: see text]) was mapped in a group of 11 healthy volunteers and calculated in striatal volumes‐of‐interest. The Wisconsin‐Card‐Sorting‐Test (WCST), Stroop‐T…
Intestinal permeability and genetic determinants in patients, first-degree relatives, and controls in a high-incidence area of Crohn's disease in Sou…
2005
1. Am J Gastroenterol. 2005 Dec;100(12):2730-6. Intestinal permeability and genetic determinants in patients, first-degree relatives, and controls in a high-incidence area of Crohn's disease in Southern Italy. Fries W, Renda MC, Lo Presti MA, Raso A, Orlando A, Oliva L, Giofré MR, Maggio A, Mattaliano A, Macaluso A, Cottone M. Dipartimento di Medicina Interna e Terapia Medica, Università di Messina, Messina, Italy. OBJECTIVE: A defect of gastrointestinal barrier function is considered to represent an important step in the pathogenesis of Crohn's disease (CD) but the mechanisms leading to an increased intestinal permeability (IP) are poorly understood. Since IP is influenced by pro-inflammat…
Natural versus enriched food: Evidence from a laboratory experiment with chewing gum.
2019
Abstract The current study explored consumers' preferences for natural versus enriched foods and identified the underlying driving forces behind consumer interest towards both attributes. A laboratory experiment with 200 respondents was carried out, applying the incentive compatible Becker-DeGroot-Marschak mechanism to measure consumers' willingness to pay for natural and enriched attributes of chewing gum. Empirical findings reveal that the two attributes are evaluated similarly by consumers. Furthermore, structural equation modelling identified a strong interdependence between the natural and the enriched attributes, suggesting they are complementary rather than substitutes/alternatives i…