Search results for "Dark"
showing 10 items of 978 documents
Eye closure in darkness animates sensory systems.
2003
Single subject and group analyses (n = 12) showed that the eyes-open and eyes-closed states in complete darkness considerably and consistently differ in the patterns of associated brain activation in fMRI. During nonchanging external stimulation, ocular motor and attentional systems were activated when the eyes were open; the visual, somatosensory, vestibular, and auditory systems were activated when the eyes were closed. These data suggest that there are two different states of mental activity: with the eyes closed, an "interoceptive" state characterized by imagination and multisensory activity and with the eyes open, an "exteroceptive" state characterized by attention and ocular motor act…
Is there a relationship between chocolate consumption and symptoms of depression? A cross-sectional survey of 13,626 US adults
2019
Objective: To examine associations between chocolate consumption and depressive symptoms in a large, representative sample of US adults. Methods: The data were from 13,626 adults (≥20 years) participating in the National Health and Nutrition Examination Survey between 2007–08 and 2013–14. Daily chocolate consumption was derived from two 24-hr dietary recalls. Depressive symptoms were assessed using the Patient Health Questionnaire (PHQ-9), with scores ≥10 indicating the presence of clinically relevant symptoms. We used multivariable logistic regression to test associations of chocolate consumption (no chocolate, non-dark chocolate, dark chocolate) and amount of chocolate consumption (grams/…
Does habituation depend on cortical inhibition? Results of a rTMS study in healthy subjects
2010
Habituation, i.e. the decremental response to repeated sensorial stimulation, is studied in humans through evoked potential stimulation. Mechanisms underlying habituation are not yet cleared, even if inhibitory circuits are supposed to play an important role. Light deprivation (LD) increases visual cortical excitability likely through down-regulation of GABA circuits. We previously found that high-frequency repetitive transcranial magnetic stimulation (hf-rTMS) can revert these facilitatory effects likely restoring the activity of inhibitory circuits. Here, we studied the effects of LD and rTMS on habituation of visual evoked potentials (VEPs). The hypothesis was that if the inhibitory circ…
Imaging the visual autokinetic illusion with fMRI
2005
During fixation of a stationary, dim light-emitting diode (LED) in complete darkness, a subtle, apparent motion is perceived which is called autokinesis. This autokinetic illusion increases with increasing fixation time. Eleven healthy subjects were examined by fMRI while fixating an LED in darkness for 35 s. BOLD signal changes of the first and the second half of the fixation period were compared. While the stimulus was the same for both periods, perception differed in that autokinesis was more pronounced in the second half. This second half of the period was associated with bilateral activations in the motion-sensitive middle occipito-temporal area known as MT/V5. Our finding suggests tha…
Monocular versus binocular pupillometry.
2004
Purpose To quantify differences between monocular and binocular pupil size measurement under scotopic and mesopic conditions. Setting Department of Ophthalmology, Johannes Gutenberg-University, and Department of Medical Biometry, Epidemiology and Informatics, University of Mainz, Mainz, Germany. Methods Computerized dynamic pupillometry (P2000 SA, Procyon Instruments Ltd.) was used at 3 illumination levels: scotopic at 0.03 lux, mesopic low at 0.82 lux, and mesopic high at 6.4 lux. One hundred forty eyes of 70 healthy volunteers without ocular pathology were examined. The subjects were divided into 2 groups. In the first group, the pupil diameter was measured binocularly first. In the secon…
Uso problemático del smartphone: el papel de los Cinco Grandes, la Tríada Oscura y la impulsividad
2021
Abstract. Este estudio examinó las relaciones entre los rasgos de personalidad de los cinco grandes (extraversión, afabilidad, neuroticismo, responsabilidad y apertura a la experiencia), la tríada oscura (maquiavelismo, psicopatía y narcisismo), la impulsividad y el uso problemático del smartphone. Doscientos dos participantes (52.48% hombres), con edades comprendidas entre los 18 y los 58 años, completaron el Ten-Item Personality Inventory, la Smartphone Addiction Scale, el Dirty Dozen y la escala de impulsividad de Plutchik. Los análisis de correlación mostraron que el uso problemático del smartphone estaba significativamente asociado a la extraversión, el neuroticismo, la impulsividad y …
Rasgos de personalidad, bienestar y malestar psicológico en usuarios de redes sociales que presentan conductas disruptivas online
2021
The present study focused on the analysis of online disruptive behavior that usually occurs among social network users. Individuals who perpetrate such behavior are commonly known as trolls or haters (Cheng, Danescu-Niculescu-Mitzil, & Leskovec, 2015). In general, they post comments, photos or provocative videos that do not pursue any purpose other than annoying or obtaining pleasure or fun (Brandel, 2007; Phillips, 2011). Recent studies have shown that certain personality traits are associated with the presence of such disruptive behavior. In this research, we studied normal personality traits, psychopathological traits, and dark personality traits in relation to disruptive behavior. The n…
Insider Trading and Market Behaviour Around Takeover Announcements in the Spanish Market
2002
As microstructure models assume informational asymmetries among investors, the possibility of insider trading is a sound reason for liquidity suppliers to increase the bid-ask spread. In this way, the tested effect that takeover announcements have on target firm returns becomes a strong motive for trading with insider information. In this paper we firstly investigate whether liquidity suppliers value the possibility of trading with informed agents in this sort of event. We analyse the adverse selection cost from bid-ask spread behaviour around takeover announcements. We find that liquidity suppliers enlarge adverse selection cost suggesting that they value the possibility of facing to insid…
Influence of the electro-optical properties of an a-Si:H single layer on the performances of a pin solar cell
2012
We analyze the results of an extensive characterization study involving electrical and optical measurements carried out on hydrogenated amorphous silicon (α-Si:H) thin film materials fabricated under a wide range of deposition conditions. By adjusting the synthesis parameters, we evidenced how conductivity, activation energy, electrical transport and optical absorption of an α-Si:H layer can be modified and optimized. We analyzed the activation energy and the pre-exponential factor of the dark conductivity by varying the dopant-to-silane gas flow ratio. Optical measurements allowed to extract the absorption spectra and the optical bandgap. Additionally, we report on the temperature dependen…
Development of a Rapid Method for the Determination of Phenolic Antioxidants in Dark Chocolate Using Ultra Performance Liquid Chromatography Coupled …
2017
Development of a new comprehensive method based on one-step liquid-liquid extraction (LLE) combined with ultra-high-performance liquid chromatography-Orbitrap high resolution mass spectrometry (UHPLC-Orbitrap-HRMS) for the determination of eight phenolic compounds in dark chocolate is demonstrated. The study focuses on the optimization of sample preparation, chromatographic separation and Orbitrap-HRMS detection parameters to adjust selectivity and sensitivity of the method. The LLE mixture of formic acid-water-acetonitrile (2:58:40, v/v) and hexane at the component ratio of 1:1 (v/v) was applied for sample preparation. The inter-day and intra-day precision expressed from the relative stand…