425 research outputs found
Assessing the effect of tandem phase Sentinel-3 OLCI Sensor uncertainty on the estimation of potential ocean chlorophyll-a trends
The Sentinel-3 tandem project represents the first time that two ocean colour satellites have been flown in the same orbit with minimal temporal separation (~30 s), thus allowing them to have virtually identical views of the ocean. This offers an opportunity for understanding how differences in individual sensor uncertainty can affect conclusions drawn from the data. Here, we specifically focus on trend estimation. Observational chlorophyll-a uncertainty is assessed from the Sentinel-3A Ocean and Land Colour Imager (OLCI-A) and Sentinel-3B OLCI (OLCI-B) sensors using a bootstrapping approach. Realistic trends are then imposed on a synthetic chlorophyll-a time series to understand how sensor uncertainty could affect potential long-term trends in Sentinel-3 OLCI data. We find that OLCI-A and OLCI-B both show very similar trends, with the OLCI-B trend estimates tending to have a slightly wider distribution, although not statistically different from the OLCI-A distribution. The spatial pattern of trend estimates is also assessed, showing that the probability distributions of trend estimates in OLCI-A and OLCI-B are most similar in open ocean regions, and least similar in coastal regions and at high northern latitudes. This analysis shows that the two sensors should provide consistent trends between the two satellites, provided future ageing is well quantified and mitigated. The Sentinel-3 programme offers a strong baseline for estimating long-term chlorophyll-a trends by offering a series of satellites (starting with Sentinel-3A and Sentinel-3B) that use the same sensor design, reducing potential issues with cross-calibration between sensors. This analysis contributes an important understanding of the reliability of the two current Sentinel-3 OLCI sensors for future studies of climate change driven chlorophyll-a trends
Underidentification of Autism Spectrum Disorder in Females: A Case Series Illustrating the Unique Presentation of this Disorder in Young Women
Autism spectrum disorder (ASD) is diagnosed more often in males than females, with the male-to-female gender ratio reported to be around 4.3:1 to 5:1. It is possible that the underrecognition of ASD in females partially contributes to this uneven ratio. Recent attention has been placed on understanding the processes that give rise to this gender difference in ASD prevalence. Socialization may contribute to the unique presentation of ASD in females, which may underlie this condition's subsequent underidentification in this group.The purpose of this case series is to demonstrate how symptoms of ASD may uniquely manifest in females without co-occurring intellectual impairment.An examination of three case examples of young women diagnosed with ASD will illustrate the processes that contribute to the atypical manifestation and underidentification of ASD in females.Across cases, the females in this study demonstrated shared symptom presentations within three domains: 1) unique core symptom manifestation (insistence on sameness, lack of social engagement, and social processing difficulties); 2) heightened psychiatric comorbidities with internalizing disorders (anxiety, depression, and borderline personality traits); and 3) emotional dysregulation. These three domains reflect specific processes that may help to explain the underidentification of ASD in females via diagnostic overshadowing.Consideration of atypical symptom presentations, heightened comorbidities, and emotion regulation difficulties may help with the understanding of why ASD symptoms in females are commonly underidentified or identified later than they are in males. Social difficulties in combination with internalizing psychiatric disorders and emotional dysregulation may lead to the development of a specific symptom presentation in females that obscures the detection of ASD symptoms. Suggestions for clinical practice are made to promote the accurate identification of ASD and to inform case formulation and treatment planning
Optimal estimation of sea surface temperature from AMSR-E
The Optimal Estimation (OE) technique is developed within the European Space Agency Climate Change Initiative (ESA-CCI) to retrieve subskin Sea Surface Temperature (SST) from AQUA’s Advanced Microwave Scanning Radiometer—Earth Observing System (AMSR-E). A comprehensive matchup database with drifting buoy observations is used to develop and test the OE setup. It is shown that it is essential to update the first guess atmospheric and oceanic state variables and to perform several iterations to reach an optimal retrieval. The optimal number of iterations is typically three to four in the current setup. In addition, updating the forward model, using a multivariate regression model is shown to improve the capability of the forward model to reproduce the observations. The average sensitivity of the OE retrieval is 0.5 and shows a latitudinal dependency with smaller sensitivity for cold waters and larger sensitivity for warmer waters. The OE SSTs are evaluated against drifting buoy measurements during 2010. The results show an average difference of 0.02 K with a standard deviation of 0.47 K when considering the 64% matchups, where the simulated and observed brightness temperatures are most consistent. The corresponding mean uncertainty is estimated to 0.48 K including the in situ and sampling uncertainties. An independent validation against Argo observations from 2009 to 2011 shows an average difference of 0.01 K, a standard deviation of 0.50 K and a mean uncertainty of 0.47 K, when considering the best 62% of retrievals. The satellite versus in situ discrepancies are highest in the dynamic oceanic regions due to the large satellite footprint size and the associated sampling effects. Uncertainty estimates are available for all retrievals and have been validated to be accurate. They can thus be used to obtain very good retrieval results. In general, the results from the OE retrieval are very encouraging and demonstrate that passive microwave observations provide a valuable alternative to infrared satellite observations for retrieving SST
Physical Aspects of Healthy Aging: Assessments of Three Measures of Balance for Studies in Middle-Aged and Older Adults
Objectives. To investigate the reliability and correlations with age of the balance components of the EPESE, NHANES, and the Good Balance Platform System (GBPS) in a normal population of adults.
Design. Cross-sectional.
Setting. Urban Medical Center in the Pacific.
Participants. A random sample of 203 healthy offspring of Honolulu Heart Program participants, ages 38–71.
Measurements. Subjects were examined twice at visits one week apart using the balance components of the EPESE, NHANES, and the good balance system tests.
Results. The EPESE and NHANES batteries of tests were not sufficiently challenging to allow successful discrimination among subjects in good health, even older subjects. The GBPS allowed objective quantitative measurements, but the test-retest correlations generally were not high. The GBPS variables correlated with age only when subjects stood on a foam pad; they also were correlated with anthropometric variables. Conclusion. Both EPESE and NHANES balance tests were too easy for healthy subjects. The GBPS had generally low reliability coefficients except for the most difficult testing condition (foam pad, eyes closed). Both height and body fat were associated with GBPS scores, necessitating adjusting for these variables if using balance as a predictor of future health
Experimental investigation of the effect of occupant characteristics on contemporary seat belt payout behavior in frontal impacts.
Objective: The goal of this study was to investigate the influence of the occupant characteristics on seat belt force vs. payout behavior based on experiment data from different configurations in frontal impacts. Methods: The data set reviewed consists of 58 frontal sled tests using several anthropomorphic test devices (ATDs) and postmortem human subjects (PMHS), restrained by different belt systems (standard belt, SB; force-limiting belt, FLB) at 2 impact severities (48 and 29 km/h). The seat belt behavior was characterized in terms of the shoulder belt force vs. belt payout behavior. A univariate linear regression was used to assess the factor significance of the occupant body mass or stature on the peak tension force and gross belt payout. Results: With the SB, the seat belt behavior obtained by the ATDs exhibited similar force slopes regardless of the occupant size and impact severities, whereas those obtained by the PMHS were varied. Under the 48 km/h impact, the peak tension force and gross belt payout obtained by ATDs was highly correlated to the occupant stature (P = .03, P = .02) and body mass (P = .05, P = .04), though no statistical difference with the stature or body mass were noticed for the PMHS (peak force: P = .09, P = .42; gross payout: P = .40, P = .48).With the FLB under the 48 km/h impact, highly linear relationshipswere noticed between the occupant body mass and the peak tension force (R2 =0.9782) and between the gross payout and stature (R2 =0.9232) regardless of the occupant types. Conclusions: The analysis indicated that the PMHScharacteristics showed a significant influence on the belt response, whereas the belt response obtained with the ATDs was more reproducible. The potential cause included the occupant anthropometry, body mass distribution, and relative motion among body segments specific to the population variance. This study provided a primary data source to understand the biomechanical interaction of the occupant with the restraint system. Further research is necessary to consider these effects in the computational studies and optimized design of the restraint system in a more realistic manner.The experiments reviewed in this study were funded by the NHTSA and Autoliv Research. The opinions expressed herein are solely those of the authors
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