1,722 research outputs found
Diagnostic ability of OCT parameters and retinal ganglion cells count in identification of glaucoma in myopic preperimetric eyes
Auditory sensory memory and working memory skills : Association between frontal MMN and performance scores
Objective: Memory is the faculty responsible for encoding, storing and retrieving information, comprising several sub-systems such as sensory memory (SM) and working memory (WM). Some previous studies exclusively using clinical population revealed associations between these two memory systems. Here we aimed at investigating the relation between modality-general WM performance and auditory SM formation indexed by magnetic mismatch negativity (MMN) responses in a healthy population of young adults. Methods: Using magnetoencephalography (MEG), we recorded MMN amplitudes to changes related to six acoustic features (pitch, timbre, location, intensity, slide, and rhythm) inserted in a 4-tone sequence in 86 adult participants who were watching a silent movie. After the MEG recordings, participants were administered the WM primary subtests (Spatial Span and Letter Number Sequencing) of Wechsler Memory Scale (WMS). Results: We found significant correlations between frontal MMN amplitudes to intensity and slide deviants and WM performance. In case of intensity, the relation was revealed in all participants, while for slide only in individuals with a musical background. Conclusions: Automatic neural responses to auditory feature changes are increased in individuals with higher visual WM performance. Significance: Conscious WM abilities might be linked to pre-attentive sensory-specific neural skills of prediction and short-term storage of environmental regularities. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe
Screening enhancement factors for laboratory CNO and rp astrophysical reactions
Cross sections of laboratory CNO and rp astrophysical reactions are enhanced
due to the presence of the multi-electron cloud that surrounds the target
nuclei. As a result the relevant astrophysical factors are overestimated unless
corrected appropriately. This study gives both an estimate of the error
committed if screening effects are not taken into account and a rough profile
of the laboratory energy thresholds at which the screening effect appears. The
results indicate that, for most practical purposes, screening corrections to
past relevant experiments can be disregarded. Regarding future experiments,
however, screening corrections to the CNO reactions will certainly be of
importance as they are closely related to the solar neutrino fluxes and the rp
process. Moreover, according to the present results, screening effects will
have to be taken into account particularly by the current and future LUNA
experiments, where screened astrophysical factors will be enhanced to a
significant degree.Comment: 6 RevTex pages + 2 ps figures. (Revised version). Accepted for
publication in Journal of Physics
Awareness and Sources of Knowledge about Obstructive Sleep Apnea: A Cross Sectional Survey Study
Obstructive sleep apnea (OSA) is a multifactorial sleep breathing disorder, seriously impacting quality of life and involving approximately 1 billion of the world’s population. It is characterized by episodes of total cessation of breathing or decreases in airflow during sleep. Available data suggest that most cases of OSA remain undiagnosed even in developed countries. This is due to a lack of widespread knowledge about this pathology and the medical morbidities and mortality it brings about, among both laypeople and physicians. Moreover, despite receiving indications about the need to undergo specific evaluations for OSA signs and symptoms, sometimes patients do not pay sufficient attention to the problem. This is probably due to a lack of correct information on these issues. The present investigation analyzed the level of knowledge about OSA pathology and the sources through which a group of OSA patients gained information on their condition. A survey of 92 patients diagnosed with OSA (mean age 60.55 ± 10.10) and referred to the Unit of Orthodontics and Dental Sleep Medicine of the University of Bologna was conducted by means of a questionnaire investigating sociodemographic characteristics, the level of general knowledge on OSA pathology and its possible medical consequences. Despite about two third (67.38%) of the population demonstrating extensive knowledge, remarkably, a group of subjects (20.65%) had poor awareness of the OSA condition. A statistically significant correlation emerged between the level of knowledge about OSA and the level of education (p = 0.002). A great effort should be made to improve the quality of information and the communication modalities for OSA to enable a fully appropriate awareness of the condition among patients
Post Retrofit Analysis of the Tuttle Creek Bridge Br. No. 16-81-2.24
The Tuttle Creek Bridge was built in 1962. Like many older welded steel bridges, it has developed fatigue cracks. The majority of cracks were forming in the upper web-gap region. In addition, fatigue cracking was occurring along gusset plates in the structure. A retrofit was performed in 1986 to prevent further fatigue cracking. Unfortunately, the cracks propagated after the retrofit. Therefore, finite element models were created at the University of Kansas to investigate the continued fatigue cracking. The models supplied a more effective retrofit procedure that included attaching the connection stiffener to the upper flange of the girder. Two tests were planned to determine the effectiveness of the retrofit. The first field test occurred before the repair was started. Its purpose was to provide stress values in key areas for comparison after the repair. In addition, the pre-retrofit test provided information for future finite element models. In 2005, the second retrofit was completed. The purpose of this report is to present results of the post-retrofit test with data from the pre-retrofit test. Comparisons of stresses for each key area are included in the report. Details of the Tuttle Creek Bridge and testing procedure are provided. In addition, minor changes from the previous test are described
Atomic effects in astrophysical nuclear reactions
Two models are presented for the description of the electron screening
effects that appear in laboratory nuclear reactions at astrophysical energies.
The two-electron screening energy of the first model agrees very well with the
recent LUNA experimental result for the break-up reaction , which so far defies all available theoretical models.
Moreover, multi-electron effects that enhance laboratory reactions of the CNO
cycle and other advanced nuclear burning stages, are also studied by means of
the Thomas-Fermi model, deriving analytical formulae that establish a lower and
upper limit for the associated screening energy. The results of the second
model, which show a very satisfactory compatibility with the adiabatic
approximation ones, are expected to be particularly useful in future
experiments for a more accurate determination of the CNO astrophysical factors.Comment: 14 RevTex pages + 2 ps (revised) figures. Phys.Rev.C (in production
Astrophysical factors:Zero energy vs. Most effective energy
Effective astrophysical factors for non-resonant astrophysical nuclear
reaction are invariably calculated with respect to a zero energy limit. In the
present work that limit is shown to be very disadvantageous compared to the
more natural effective energy limit. The latter is used in order to modify the
thermonuclear reaction rate formula so that it takes into account both plasma
and laboratory screening effects.Comment: 7 RevTex pages. Accepted for publication in Phys.Rev.
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