1,393 research outputs found
Artificial Neural Networks to reconstruct incomplete satellite data: application to the Mediterranean Sea Surface Temperature
Satellite data can be very useful in applications where extensive spatial information is needed, but sometimes missing data due to presence of clouds can affect data quality. In this study a methodology for pre-processing sea surface temperature (SST) data is proposed. The methodology, that processes measures in the visible wavelength, is based on an Artificial Neural Network (ANN) system. The effectiveness of the procedure has been also evaluated comparing results obtained using an interpolation method. After the methodology has been identified, a validation is performed on 3 different episodes representative of SST variability in the Mediterranean sea. The proposed technique can process SST NOAA/AVHRR data to simulate severe storm episodes by means of prognostic meteorological models
Simulation of feed restriction and fasting: Effects on animal recovery and gastrointestinal permeability in unweaned Angus-Holstein calves
Feed restriction and fasting experienced during commercial production negatively affect unweaned calves' behavior and health status. Transportation and stays at assembly centers are the main factors generating these disorders. For this study, 20 unweaned Angus-Holstein bull calves [44.1 ± 2.04 kg of body weight (BW) and 14.7 ± 0.63 d of age (± standard error)] were used to evaluate the effects of feed restriction and fasting on performance, energy status [serum concentration of glucose, β-hydroxybutyrate (BHB), and nonesterified fatty acids], and gastrointestinal permeability [serum concentration of citrulline, chromium (Cr)-EDTA, lactulose, and d-mannitol]. Calves were randomly assigned to 1 of 4 treatments that simulated the feed restrictions of an assembly center situation on one hand, and the fasting hours during transportation on the other. Treatments were as follows. Control (CT): from d −4 to −1, calves were fed 2.5 L of milk replacer (MR) twice daily; concentrate and straw were offered ad libitum. Mild (MD): calves were fed only MR (d −4 to −1) as described for CT, and on d −1 calves were subjected to a 9-h feed withdrawal. Moderate (MO): calves were fed only MR (d −4 to −1) as described for CT and on d −1 subjected to a 19-h feed withdrawal. Severe (SV): calves were fed only 2.5 L of a rehydrating solution twice daily (d −4 to −1) and on d −1 subjected to a 19-h feed withdrawal. From d 0 to d 42 (weaning) all calves were fed the same feeding program (MR, concentrate, and straw ad libitum). Results showed that BW was greater for the CT treatment compared with the others from d 0 to d 7, whereas BW of SV was lesser compared with the others from d −1 to d 7. No differences among treatments were observed at weaning. At d 2 concentrate intakes of MD, MO, and SV were lesser compared with CT. By d 4, concentrate intake of SV was similar to that for CT and greater than MD and MO. Similarly to BW, no differences in concentrate intake among treatments were observed at weaning on d 42 of the study. At d −1 for SV and d 0 in all restricted calves, serum glucose concentration was lesser compared with CT. At d −1 and 0, nonesterified fatty acids and BHB serum concentrations were greater in the SV calves compared with the other treatments. By d 2, serum concentrations of nonesterified fatty acids, BHB, and glucose were restored to CT levels. At d −1 serum citrulline concentration was lesser in SV and greater in MD calves. The CT calves had lower serum concentrations of Cr-EDTA (d −1 and d 0), lactulose (d 0), and d-mannitol (d 0) compared with the other restricted calves. Results showed that degree of dietary restriction, type of liquid diet (MR or rehydrating solution), and fasting hours (9 vs. 19 h) affected calves' BW, concentrate intake, and serum concentration of markers indicative of energy status and gastrointestinal permeability.info:eu-repo/semantics/publishedVersio
Long-term musical experience and auditory and visual perceptual abilities under adverse conditions
Musicians have been shown to have enhanced speech perception in noise skills. It is unclear whether these improvements are limited to the auditory modality, as no research has examined musicians' visual perceptual abilities under degraded conditions. The current study examined associations between long-term musical experience and visual perception under noisy or degraded conditions. The performance of 11 musicians and 11 age-matched nonmusicians was compared on several auditory and visual perceptions in noise measures. Auditory perception tests included speech-in-noise tests and an environmental sound in noise test. Visual perception tasks included a fragmented sentences task, an object recognition task, and a lip-reading measure. Participants' vocabulary knowledge and nonverbal reasoning abilities were also assessed. Musicians outperformed nonmusicians on the speech perception in noise measures as well as the visual fragmented sentences task. Musicians also displayed better vocabulary knowledge in comparison to nonmusicians. Associations were found between perception of speech and visually degraded text. The findings show that long-term musical experience is associated with modality-general improvements in perceptual abilities. Possible systems supporting musicians' perceptual abilities are discussed
Verbal Processing Speed and Executive Functioning in Long-Term Cochlear Implant Users
Purpose: The purpose of this study was to report how verbal rehearsal speed (VRS), a form of covert speech used to maintain verbal information in working memory, and another verbal processing speed measure, perceptual encoding speed, are related to 3 domains of executive function (EF) at risk in cochlear implant (CI) users: verbal working memory, fluency-speed, and inhibition-concentration.
Method: EF, speech perception, and language outcome measures were obtained from 55 prelingually deaf, long-term CI users and matched controls with normal hearing (NH controls). Correlational analyses were used to assess relations between VRS (articulation rate), perceptual encoding speed (digit and color naming), and the outcomes in each sample.
Results: CI users displayed slower verbal processing speeds than NH controls. Verbal rehearsal speed was related to 2 EF domains in the NH sample but was unrelated to EF outcomes in CI users. Perceptual encoding speed was related to all EF domains in both groups.
Conclusions: Verbal rehearsal speed may be less influential for EF quality in CI users than for NH controls, whereas rapid automatized labeling skills and EF are closely related in both groups. CI users may develop processing strategies in EF tasks that differ from the covert speech strategies routinely employed by NH individuals
Short-Term and Working Memory Impairments in Early-Implanted, Long-Term Cochlear Implant Users Are Independent of Audibility and Speech Production
OBJECTIVE: To determine whether early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated.
DESIGN: Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions that differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing).
RESULTS: Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response.
CONCLUSIONS: Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory using phonological and linguistic strategies during memory tasks
Visual-spatial sequence learning and memory in trained musicians
Previous research has shown that musicians have enhanced visual-spatial abilities and sensorymotor skills. As a result of their long-term musical training and their experience-dependent activities, musicians may learn to associate sensory information with fine motor movements. Playing a musical instrument requires musicians to rapidly translate musical symbols into specific sensory-motor actions while also simultaneously monitoring the auditory signals produced by their instrument. In this study, we assessed the visual-spatial sequence learning and memory abilities of long-term musicians. We recruited 24 highly trained musicians and 24 nonmusicians, individuals with little or no musical training experience. Participants completed a visual-spatial sequence learning task as well as receptive vocabulary, nonverbal reasoning, and short-term memory tasks. Results revealed that musicians have enhanced visual-spatial sequence learning abilities relative to nonmusicians. Musicians also performed better than nonmusicians on the vocabulary and nonverbal reasoning measures. Additional analyses revealed that the large group difference observed on the visualspatial sequencing task between musicians and nonmusicians remained even after controlling for vocabulary, nonverbal reasoning, and short-term memory abilities. Musicians' improved visualspatial sequence learning may stem from basic underlying differences in visual-spatial and sensorymotor skills resulting from long-term experience and activities associated with playing a musical instrument
Excited states in bilayer graphene quantum dots
We report on ground- and excited state transport through an electrostatically
defined few-hole quantum dot in bilayer graphene in both parallel and
perpendicular applied magnetic fields. A remarkably clear level scheme for the
two-particle spectra is found by analyzing finite bias spectroscopy data within
a two-particle model including spin and valley degrees of freedom. We identify
the two-hole ground-state to be a spin-triplet and valley-singlet state. This
spin alignment can be seen as Hund's rule for a valley-degenerate system, which
is fundamentally different to quantum dots in carbon nano tubes and GaAs-based
quantum dots. The spin-singlet excited states are found to be valley-triplet
states by tilting the magnetic field with respect to the sample plane. We
quantify the exchange energy to be 0.35meV and measure a valley and spin
g-factor of 36 and 2, respectively
Neurocognitive factors in sensory restoration of early deafness: a connectome model
Progress in biomedical technology (cochlear, vestibular, and retinal implants) has led to remarkable success in neurosensory restoration, particularly in the auditory system. However, outcomes vary considerably, even after accounting for comorbidity-for example, after cochlear implantation, some deaf children develop spoken language skills approaching those of their hearing peers, whereas other children fail to do so. Here, we review evidence that auditory deprivation has widespread effects on brain development, affecting the capacity to process information beyond the auditory system. After sensory loss and deafness, the brain's effective connectivity is altered within the auditory system, between sensory systems, and between the auditory system and centres serving higher order neurocognitive functions. As a result, congenital sensory loss could be thought of as a connectome disease, with interindividual variability in the brain's adaptation to sensory loss underpinning much of the observed variation in outcome of cochlear implantation. Different executive functions, sequential processing, and concept formation are at particular risk in deaf children. A battery of clinical tests can allow early identification of neurocognitive risk factors. Intervention strategies that address these impairments with a personalised approach, taking interindividual variations into account, will further improve outcomes
Combined surgical and endoscopic approach for the reduction of a congenital hiatal hernia in a cat: a case report
A case of surgical resolution of type I or \u201csliding\u201d hiatal hernia is reported. A seven-month-old
kitten was presented because of abdominal discomfort, accelerated breathing after eating and chronic vomiting.
The clinical examination was unremarkable. Thoracic radiographs and gastroscopy led to the diagnosis of
type I hiatal hernia. The surgical resolution consisted of hiatal plication, oesophagopexy and left-flank incisional
gastropexy. All procedures were carried out using a 6 mm videoendoscope positioned in the stomach to evaluate
the right oesophago-gastric junction reduction. One week after surgery there was a recurrence of symptoms and
a second laparotomy was performed. During the second surgery additional hiatal plication was necessary and an
oesophagopexy was repeated after dissection of the phrenico-oesophageal ligament. Moreover, a new incisional
gastropexy was carried out after resolution of the first one. The cat recovered without complications and at oneyear
follow-up did show no signs related to the hiatal hernia. This communication reports on possible additional
surgical techniques in cases of type I hiatal hernia and contributes to an understanding of the importance of
oesophagopexy in cases of hiatus malformation
Endoscopy-assisted tracheal reconstruction of post-traumatic obstruction in a cat: A case report
A domestic shorthair cat was referred with a history of dyspnoea and lethargy that had arisen gradually
within the last few days. The cat had been hit by an automobile 10 days earlier. A thoracic radiograph suggested
stenosis of the intrathoracic trachea, proximal to the tracheal bifurcation. Endoscopic examination confirmed
a narrowing of the tracheal lumen due to the presence of a fibrotic ring, with remaining patent lumen of about
2 mm. A surgical treatment with a right lateral thoracotomy approach and resection of the narrowed portion of
the trachea (a length of about 1 cm) was performed under endoscopic vision. The procedure was unsuccessful
because of the size of the tissue removed and the laxity of the remaining tracheal tissue that caused dehiscence of
sutures between the tracheal stump and tracheal bifurcation. After consultation with the cat\u2019s owners, an intraoperative
euthanasia was performed
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