10 research outputs found
Observations with stabilized retinal images and their neural correlates: a theory on the perception of constant brightness
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mmubn000001_182422828.pdf (publisher's version ) (Open Access)Promotor : A. Vendrik103 p
Specific heat study of iron-based narrow- and wide-gap diluted magnetic semiconductors
The specific heat of II-IV group Fe-based DMS has been investigated at temperatures below 20 K. All zero- and open-gap compounds have a magnetically inactive singlet ground state, well separated from the excited states. Within a crystal field model one is in principle able to understand this behaviour in all cases. The Fe2+-Fe2+ interaction and the role of the Fe levels in the band structure will be discussed
Magnetization steps in iron-based diluted magnetic semiconductors
The high-field magnetization of diluted magnetic semiconductors (DMS) has been calculated for magnetic ions with spin and orbital momenta. In particular, it is shown that, in addition to the spin-only case (Mn2+), also for Fe-based DMS characteristic steps in the low-temperature magnetization should be detectable. The position of the first step in the magnetization, being almost insensitive for crystal-field parameters and sample orientation, can be used to establish the nearest-neighbor interaction (JNN), provided that ÂżJNNÂż exceeds a critical value
Personality and motivation for body donation
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99595.pdf (publisher's version ) (Closed access)Background: This study examines the relationship between motivation for body donation to science and personality characteristics using a body donor survey (N = 759) conducted by the University Medical Centre Groningen (UMCG) in The Netherlands. The survey expands on anthropological studies that suggest an association between donor motivation and personality. Methods: A structural equation model was used to investigate the relationship between personality and motivation for body donation. Findings: The results show that, compared to society at large, body donors have a similar spectrum of personality characteristics. However, we found statistically significant positive relationships between donor motivation and Big Five personality traits. Together the personality traits explain between 5% and 15% of the variance in motivation for body donation. Conclusions: We argue that donor campaigns should not focus solely on altruistic motives, but should include the aspect of possible personal achievement by the donor. This is a fruitful starting point for approaching potential donors and anticipating their needs.6 p
Yield of peripheral sodium channels gene screening in pure small fibre neuropathy
BACKGROUND:
Neuropathic pain is common in peripheral neuropathy. Recent genetic studies have linked pathogenic voltage-gated sodium channel (VGSC) variants to human pain disorders. Our aims are to determine the frequency of SCN9A, SCN10A and SCN11A variants in patients with pure small fibre neuropathy (SFN), analyse their clinical features and provide a rationale for genetic screening.
METHODS:
Between September 2009 and January 2017, 1139 patients diagnosed with pure SFN at our reference centre were screened for SCN9A, SCN10A and SCN11A variants. Pathogenicity of variants was classified according to established guidelines of the Association for Clinical Genetic Science and frequencies were determined. Patients with SFN were grouped according to the VGSC variants detected, and clinical features were compared.
RESULTS:
Among 1139 patients with SFN, 132 (11.6%) patients harboured 73 different (potentially) pathogenic VGSC variants, of which 50 were novel and 22 were found in 65 1 patient. The frequency of (potentially) pathogenic variants was 5.1% (n=58/1139) for SCN9A, 3.7% (n=42/1139) for SCN10A and 2.9% (n=33/1139) for SCN11A. Only erythromelalgia-like symptoms and warmth-induced pain were significantly more common in patients harbouring VGSC variants.
CONCLUSION:
(Potentially) pathogenic VGSC variants are present in 11.6% of patients with pure SFN. Therefore, genetic screening of SCN9A, SCN10A and SCN11A should be considered in patients with pure SFN, independently of clinical features or underlying conditions
Neural Mechanisms for Representing Surface and Contour Features
Contours and surfaces are basic qualities which are processed by the visual system to aid the successful behavior of autonomous beings within the environment. There is increasing evidence that the two modalities of contours and surfaces are processed in separate, but interacting visual streams or sub-systems. Neurons at early stages in the visual system show strong responses only at locations of high contrast, such as edges, but only weak responses within homogeneous regions. Thus, for the processing and representation of surfaces, the visual system has to integrate sparse local measurements into a dense, coherent representation