499 research outputs found
Multidisciplinary Expert-aided Analysis and Design (MEAD)
The MEAD Computer Program (MCP) is being developed under the Multidisciplinary Expert-Aided Analysis and Design (MEAD) Project as a CAD environment in which integrated flight, propulsion, and structural control systems can be designed and analyzed. The MCP has several embedded computer-aided control engineering (CACE) packages, a user interface (UI), a supervisor, a data-base manager (DBM), and an expert system (ES). The supervisor monitors and coordinates the operation of the CACE packages, the DBM; the ES, and the UI. The DBM tracks the control design process. Models created or installed by the MCP are tracked by date and version, and results are associated with the specific model version with which they were generated. The ES is used to relieve the control engineer from tedious and cumbersome tasks in the iterative design process. The UI provides the capability for a novice as well as an expert to utilize the MCP easily and effectively. The MCP version 2(MCP-2.0) is fully developed for flight control system design and analysis. Propulsion system modeling, analysis, and simulation is also supported; the same is true for structural models represented in state-space form. The ultimate goal is to cover the integration of flight, propulsion, and structural control engineering, including all discipline-specific functionality and interfaces. The current MCP-2.0 components and functionality are discussed
Motor Performance Is not Enhanced by Daytime Naps in Older Adults
The impact of sleep on motor learning in the aging brain was investigated using an experimental diurnal nap setup. As the brain ages several components of learning as well as motor performance change. In addition, aging is also related to sleep architectural changes. This combination of slowed learning processes and impaired sleep behavior raises the question of whether sleep can enhance learning and specifically performance of procedural tasks in healthy, older adults. Previous research was able to show sleep-dependent consolidation overnight for numerous tasks in young adults. Some of these study findings can also be replicated for older adults. This study aims to clarify whether sleep-dependent consolidation can also be found during shorter periods of diurnal sleep. The impact of midday naps on motor consolidation was analyzed by comparing procedural learning using a sequence and a motor adaptation task, in a crossover fashion in healthy, non-sleep deprived, older adults randomly subjected to wake (45 min), short nap (10-20 min sleep) or long nap (50-70 min sleep) conditions. Older adults exhibited learning gains, these were not found to be sleep-dependent in either task. The results suggest that daytime naps do not have an impact on performance and motor learning in an aging population
Feasibility of cardiac output measurements in critically ill patients by medical students
Background: Critical care ultrasonography (CCUS) is increasingly applied also in the intensive care unit (ICU) and performed by non-experts, including even medical students. There is limited data on the training efforts necessary for novices to attain images of sufficient quality. There is no data on medical students performing CCUS for the measurement of cardiac output (CO), a hemodynamic variable of importance for daily critical care. Objective: The aim of this study was to explore the agreement of cardiac output measurements as well as the quality of images obtained by medical students in critically ill patients compared to the measurements obtained by experts in these images. Methods: In a prospective observational cohort study, all acutely admitted adults with an expected ICU stay over 24 h were included. CCUS was performed by students within 24 h of admission. CCUS included the images required to measure the CO, i.e., the left ventricular outflow tract (LVOT) diameter and the velocity time integral (VTI) in the LVOT. Echocardiography experts were involved in the evaluation of the quality of images obtained and the quality of the CO measurements. Results: There was an opportunity for a CCUS attempt in 1155 of the 1212 eligible patients (95%) and in 1075 of the 1212 patients (89%) CCUS examination was performed by medical students. In 871 out of 1075 patients (81%) medical students measured CO. Experts measured CO in 783 patients (73%). In 760 patients (71%) CO was measured by both which allowed for comparison; bias of CO was 0.0 L min−1 with limits of agreement of − 2.6 L min−1 to 2.7 L min−1. The percentage error was 50%, reflecting poor agreement of the CO measurement by students compared with the experts CO measurement. Conclusions: Medical students seem capable of obtaining sufficient quality CCUS images for CO measurement in the majority of critically ill patients. Measurements of CO by medical students, however, had poor agreement with expert measurements. Experts remain indispensable for reliable CO measurements. Trial registration Clinicaltrials.gov; http://www.clinicaltrials.gov; registration number NCT02912624
Transboundary Water: Improving Methodologies and Developing Integrated Tools to Support Water Security
River basins for which transboundary coordination and governance is a factor are of concern to US national security, yet there is often a lack of sufficient data-driven information available at the needed time horizons to inform transboundary water decision-making for the intelligence, defense, and foreign policy communities. To address this need, a two-day workshop entitled Transboundary Water: Improving Methodologies and Developing Integrated Tools to Support Global Water Security was held in August 2017 in Maryland. The committee that organized and convened the workshop (the Organizing Committee) included representatives from the National Aeronautics and Space Administration (NASA), the US Army Corps of Engineers Engineer Research and Development Center (ERDC), and the US Air Force. The primary goal of the workshop was to advance knowledge on the current US Government and partners' technical information needs and gaps to support national security interests in relation to transboundary water. The workshop also aimed to identify avenues for greater communication and collaboration among the scientific, intelligence, defense, and foreign policy communities. The discussion around transboundary water was considered in the context of the greater global water challenges facing US national security
Trumpler 16-26: A New Centrifugal Magnetosphere Discovered via SDSS/APOGEE H-band Spectroscopy
We report the discovery of a new example of the rare class of highly
magnetized, rapidly rotating, helium enhanced, early B stars that produce
anomalously wide hydrogen emission due to a centrifugal magnetosphere (CM). The
star is Trumpler 16-26, a B1.5 V member of the Trumpler 16 open cluster. A CM
was initially suspected based on hydrogen Brackett series emission observed in
SDSS/APOGEE -band spectra. Similar to the other stars of this type, the
emission was highly variable and at all times remarkable due to the extreme
velocity separations of the double peaks (up to 1300 km s.) Another clue
lay in the TESS lightcurve, which shows two irregular eclipses per cycle when
phased with the likely 0.9718115 day rotation period, similar to the behavior
of the well known CM host star Ori E. To confirm a strong magnetic
field and rotation-phase-locked variability, we initiated a follow-up campaign
consisting of optical spectropolarimetry and spectroscopy. The associated data
revealed a longitudinal magnetic field varying between and kG
with the period found from photometry. The optical spectra confirmed rapid
rotation ( km s), surface helium enhancement, and wide,
variable hydrogen emission. Tr16-26 is thus confirmed as the 20
known, the fourth most rapidly rotating, and the faintest CM host star yet
discovered. With a projected dipole magnetic field strength of
kG, Tr16-26 is also among the most magnetic CM stars
Time-Frequency Analysis of Chemosensory Event-Related Potentials to Characterize the Cortical Representation of Odors in Humans
BACKGROUND: The recording of olfactory and trigeminal chemosensory event-related potentials (ERPs) has been proposed as an objective and non-invasive technique to study the cortical processing of odors in humans. Until now, the responses have been characterized mainly using across-trial averaging in the time domain. Unfortunately, chemosensory ERPs, in particular, olfactory ERPs, exhibit a relatively low signal-to-noise ratio. Hence, although the technique is increasingly used in basic research as well as in clinical practice to evaluate people suffering from olfactory disorders, its current clinical relevance remains very limited. Here, we used a time-frequency analysis based on the wavelet transform to reveal EEG responses that are not strictly phase-locked to onset of the chemosensory stimulus. We hypothesized that this approach would significantly enhance the signal-to-noise ratio of the EEG responses to chemosensory stimulation because, as compared to conventional time-domain averaging, (1) it is less sensitive to temporal jitter and (2) it can reveal non phase-locked EEG responses such as event-related synchronization and desynchronization. METHODOLOGY/PRINCIPAL FINDINGS: EEG responses to selective trigeminal and olfactory stimulation were recorded in 11 normosmic subjects. A Morlet wavelet was used to characterize the elicited responses in the time-frequency domain. We found that this approach markedly improved the signal-to-noise ratio of the obtained EEG responses, in particular, following olfactory stimulation. Furthermore, the approach allowed characterizing non phase-locked components that could not be identified using conventional time-domain averaging. CONCLUSION/SIGNIFICANCE: By providing a more robust and complete view of how odors are represented in the human brain, our approach could constitute the basis for a robust tool to study olfaction, both for basic research and clinicians
Right Heart Dysfunction in Heart Failure with Preserved Ejection Fraction:the Impact of Atrial Fibrillation
BACKGROUND: Right ventricular (RV) dysfunction and atrial fibrillation (AF) frequently coexist in heart failure with preserved ejection fraction (HFpEF). The mechanisms underlying the association between AF and RV dysfunction are incompletely understood. METHODS AND RESULTS: 102 patients were identified. RV function was assessed using multiple echocardiographic parameters and dysfunction was present if ≥2 parameters were below the recommended cutoff. RV function, right atrial (RA) reservoir strain and RA emptying fraction, were compared between AF and sinus rhythm. 91 patients with sufficient echocardiographic quality were included: 45 (50%) had no history of AF; 14 (15%) had prior AF while in sinus rhythm; 32 (35%) had current AF. The prevalence of RV dysfunction varied across subgroups never AF, prior AF and current AF (20%, 43% and 63%, respectively, p=0.001). AF was associated with RV dysfunction (OR 4.70 [1.82-12.1], p=0.001) - independent of pulmonary pressures. In patients in sinus rhythm with prior AF, RA emptying fraction was lower compared to patients without AF history (41 vs. 60%, p=0.002). Prior AF was also associated with reduced RA reservoir strain (OR 4.57 [1.05-19.9], p=0.04) - independent of RV end-diastolic pressure. CONCLUSIONS: Atrial fibrillation is strongly related to reduced RV and RA function in HFpEF, independent of pulmonary pressures
Gustatory Function in Acute COVID‐19 ‐ Results From Home‐Based Psychophysical Testing
Objective
Gustatory function during COVID-19 is self-reported by around 50% of patients. However, only a few studies assessed gustation using psychophysical testing during acute infection. The objective of this study is to test gustatory function on threshold tests in the very first days of COVID-19.
Methods
Psychophysical testing consisted of validated and blinded tests for olfaction (NHANES Pocket Smell Test) and gustation (Taste Strips Test). These test kits were sent to home-quarantined patients and self-administered using a detailed instruction sheet.
Results
A total of 51 patients were included in this study. Testing was performed 6.5 ± 2.7 days after sampling of respiratory swabs. At this time 37% of patients stated to currently experience a gustatory impairment. The mean Taste Strips score was 10.0 ± 3.4 with 28% scoring in the range of hypogeusia. Interestingly, no significant difference in the results of gustatory testing could be observed between the group with subjectively preserved gustation and the group with self-rated taste impairment.
Conclusion
During the very first days of COVID-19, psychophysical gustatory testing revealed hypogeusia in 28%. This is far lower than patients' self-reports. Different from previous studies, we did not find clear evidence for an impairment of only certain taste qualities
Comparison of COVID-19 and common cold chemosensory dysfunction
Anosmia constitutes a prominent symptom of COVID-19. However, anosmia is also a common symptom of acute colds of various origins. In contrast to an acute cold, it appears from several questionnaire-based studies that in the context of COVID-19 infection, anosmia is the main rhinological symptom and is usually not associated with other rhinological symptoms such as rhinorrhoea or nasal obstruction. Until now, no study has directly compared smell and taste function between COVID-19 patients and patients with other causes of upper respiratory tract infection (URTI) using valid and reliable psychophysical tests. In this study, we aimed to objectively assess and compare olfactory and gustatory functions in 10 COVID-19 patients (PCR diagnosed, assessed on average 2 weeks after infection), 10 acute cold (AC) patients (assessed before the COVID-19 outbreak) and 10 healthy controls, matched for age and sex. Smell performance was assessed using the extended "Sniffin' Sticks" test battery (4), while taste function was assessed using "taste strips" (5). Receiver Operating Characteristic (ROC) curves were built to probe olfactory and gustatory scores in terms of their discrimination between COVID-19 and AC patients. Our results suggest that mechanisms of COVID-19 related olfactory dysfunction are different from those seen in an AC and may reflect, at least to some extent, a specific involvement at the level of central nervous system in some COVID-19 patients. In the future, studies to assess the prevalence of persistent anosmia and neuroanatomical changes on MRI correlated to chemosensory function, will be useful to understand these mechanisms
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