137 research outputs found

    Estimating Random Errors Due to Shot Noise in Backscatter Lidar Observations

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    In this paper, we discuss the estimation of random errors due to shot noise in backscatter lidar observations that use either photomultiplier tube (PMT) or avalanche photodiode (APD) detectors. The statistical characteristics of photodetection are reviewed, and photon count distributions of solar background signals and laser backscatter signals are examined using airborne lidar observations at 532 nm using a photon-counting mode APD. Both distributions appear to be Poisson, indicating that the arrival at the photodetector of photons for these signals is a Poisson stochastic process. For Poisson-distributed signals, a proportional, one-to-one relationship is known to exist between the mean of a distribution and its variance. Although the multiplied photocurrent no longer follows a strict Poisson distribution in analog-mode APD and PMT detectors, the proportionality still exists between the mean and the variance of the multiplied photocurrent. We make use of this relationship by introducing the noise scale factor (NSF), which quantifies the constant of proportionality that exists between the root-mean-square of the random noise in a measurement and the square root of the mean signal. Using the NSF to estimate random errors in lidar measurements due to shot noise provides a significant advantage over the conventional error estimation techniques, in that with the NSF uncertainties can be reliably calculated from/for a single data sample. Methods for evaluating the NSF are presented. Algorithms to compute the NSF are developed for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar and tested using data from the Lidar In-space Technology Experiment (LITE). OCIS Codes

    Simulation Based Training Improves Airway Management for Helicopter EMS Teams

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    The use of paralytic medications in the performance of RSI intubation is a high risk intervention used by many HEMS crews. There is no margin for error in RSI intubation as the results can be fatal. Operating room access for airway management training has become more difficult, and is not representative of the environment in which HEMS crews typically function. LifeEvac of Virginia designed and implemented an SST airway management program to provide a realistic, consistent training platform. The dynamic program incorporates standardized scenarios, and real life challenging cases that this and other programs have encountered. SST is done in a variety of settings including the helicopter, back of ambulances, staged car crashes and simulation centers. The result has been the indoctrination of a well defined, consistent approach to every airway management intervention. The SST program facillitates enhancement of technical skills. as well as team dynamics and communication

    Beyond the Social Determinants of Learning™ A Walden University Position Paper

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    The Social Determinants of Health (SDOH), presented by the World Health Organization (WHO) and a cross-organizational global commission in the early 2000s, provide an understanding of health status of individuals and communities. SDOH consider societal forces and conditions such as housing, work conditions, environment, and education (Braveman & Gottlieb, 2014; WHO, 2021). The U.S. Department of Health and Human Services (n.d.) launched a “Healthy People 2030” initiative, addressing five key social determinants of health and offering a framework from which organizations can build strategy: 1. Healthcare access and quality 2. Education access and quality 3. Social and community context 4. Economic stability 5. Neighborhood and built environment As leaders in preparing provisioners of healthcare, Walden’s nursing and healthcare programs operate from the Social Determinants of Health & Healthcare (SDOH&H) framework (emphasizing both health and healthcare) and address the SDOH&H in every course

    CALIOP Version 3 Data Products: A Comparison to Version 2

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    After launch we discovered that the CALIOP daytime measurements were subject to thermally induced beamdrift,and this caused the calibration to vary by as much as 30% during the course of a single daytime orbit segment. Using an algorithm developed by Powell et al.(2010), empirically derived correction factors are now computed in near realtime as a function of orbit elapsed time, and these are used to compensate for the beam wandering effects

    Technological capabilities to assess digital excellence in hospitals in high performing healthcare systems::an international eDelphi exercise

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    Background: Hospitals worldwide are developing ambitious digital transformation programs as part of broader efforts to create digitally advanced health care systems. However, there is as yet no consensus on how best to characterize and assess digital excellence in hospitals. Objective: Our aim was to develop an international agreement on a defined set of technological capabilities to assess digital excellence in hospitals. Methods: We conducted a two-stage international modified electronic Delphi (eDelphi) consensus-building exercise, which included a qualitative analysis of free-text responses. In total, 31 international health informatics experts participated, representing clinical, academic, public, and vendor organizations. Results: We identified 35 technological capabilities that indicate digital excellence in hospitals. These are divided into two categories: (a) capabilities within a hospital (n=20) and (b) capabilities enabling communication with other parts of the health and social care system, and with patients and carers (n=15). The analysis of free-text responses pointed to the importance of nontechnological aspects of digitally enabled change, including social and organizational factors. Examples included an institutional culture characterized by a willingness to transform established ways of working and openness to risk-taking. The availability of a range of skills within digitization teams, including technological, project management and business expertise, and availability of resources to support hospital staff, were also highlighted. Conclusions: We have identified a set of criteria for assessing digital excellence in hospitals. Our findings highlight the need to broaden the focus from technical functionalities to wider digital transformation capabilities

    Barriers and supports to implementation of MDI/spacer use in nine Canadian pediatric emergency departments: a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Despite recent research supporting the use of metered dose inhalers with spacer devices (MDI/spacers) in pediatric emergency departments (PEDs) for acute exacerbations of asthma, uptake of this practice has been slow. The objectives of this study were to determine the barriers and supports to implementing MDI/spacer research and to identify factors associated with early and late adoption of MDI/spacers in Canadian PEDs.</p> <p>Methods</p> <p>Using a comparative case study design, we classified nine tertiary care pediatric hospital PEDs based on their stage of implementation. Data were collected using focus group interviews with physicians, registered nurses (RNs), and respiratory therapists (RTs), and individual interviews with both patient care and medical directors at each site. Initial coding was based on the Ottawa Model of Research Use (OMRU) categories of elements known to influence the uptake of innovations.</p> <p>Results</p> <p>One hundred and fifty healthcare professionals from nine different healthcare institutions participated in this study. Lack of leadership in the form of a research champion, a lack of consensus about the benefits of MDI/spacers among staff, perceived resistance from patients/parents, and perceived increased cost and workload associated with MDI/spacer use were the most prevalent barriers to the adoption of the MDI/spacer. Common strategies used by early-adopting sites included the active participation of all professional groups in the adoption process in addition to a well-planned and executed educational component for staff, patients, and families. Early adopter sites were also more likely to have the MDI/spacer included in a clinical protocol/pathway.</p> <p>Conclusion</p> <p>Potential barriers and supports to implementation have been identified that will help EDs adopt MDI/spacer use. Future interventions intended to increase MDI/spacer use in PEDs will need to be sensitive to the barriers identified in this study.</p

    Light Curves and Colors of the Ejecta from Dimorphos after the DART Impact

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    On 26 September 2022 the Double Asteroid Redirection Test (DART) spacecraft impacted Dimorphos, a satellite of the asteroid 65803 Didymos. Because it is a binary system, it is possible to determine how much the orbit of the satellite changed, as part of a test of what is necessary to deflect an asteroid that might threaten Earth with an impact. In nominal cases, pre-impact predictions of the orbital period reduction ranged from ~8.8 - 17.2 minutes. Here we report optical observations of Dimorphos before, during and after the impact, from a network of citizen science telescopes across the world. We find a maximum brightening of 2.29 ±\pm 0.14 mag upon impact. Didymos fades back to its pre-impact brightness over the course of 23.7 ±\pm 0.7 days. We estimate lower limits on the mass contained in the ejecta, which was 0.3 - 0.5% Dimorphos' mass depending on the dust size. We also observe a reddening of the ejecta upon impact.Comment: Accepted by Natur

    Significant Impact of Sequence Variations in the Nucleoprotein on CD8 T Cell-Mediated Cross-Protection against Influenza A Virus Infections

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    Background: Memory CD8 T cells to influenza A viruses are widely detectable in healthy human subjects and broadly cross-reactive for serologically distinct influenza A virus subtypes. However, it is not clear to what extent such pre-existing cellular immunity can provide cross-subtype protection against novel emerging influenza A viruses. Methodology/Principal: Findings We show in the mouse model that naturally occurring sequence variations of the conserved nucleoprotein of the virus significantly impact cross-protection against lethal disease in vivo. When priming and challenge viruses shared identical sequences of the immunodominant, protective NP366/Db epitope, strong cross-subtype protection was observed. However, when they did not share complete sequence identity in this epitope, cross-protection was considerably reduced. Contributions of virus-specific antibodies appeared to be minimal under these circumstances. Detailed analysis revealed that the magnitude of the memory CD8 T cell response triggered by the NP366/Db variants was significantly lower than those triggered by the homologous NP366/Db ligand. It appears that strict specificity of a dominant public TCR to the original NP366/Db ligand may limit the expansion of cross-reactive memory CD8 T cells to the NP366/Db variants. Conclusions/Significance: Pre-existing CD8 T cell immunity may provide substantial cross-protection against heterosubtypic influenza A viruses, provided that the priming and the subsequent challenge viruses share the identical sequences of the immunodominant, protective CTL epitopes

    High incidence of Noonan syndrome features including short stature and pulmonic stenosis in patients carrying NF1 missense mutations affecting p.Arg1809: genotype-phenotype correlation

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    Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders, affecting 1:3,000 worldwide. Identification of genotype-phenotype correlations is challenging because of the wide range clinical variability, the progressive nature of the disorder, and extreme diversity of the mutational spectrum. We report 136 individuals with a distinct phenotype carrying one of five different NF1 missense mutations affecting p.Arg1809. Patients presented with multiple cafe-au-lait macules (CALM) with or without freckling and Lisch nodules, but no externally visible plexiform neurofibromas or clear cutaneous neurofibromas were found. About 25% of the individuals had Noonan-like features. Pulmonic stenosis and short stature were significantly more prevalent compared with classic cohorts (P<0.0001). Developmental delays and/or learning disabilities were reported in over 50% of patients. Melanocytes cultured from a CALM in a segmental NF1-patient showed two different somatic NF1 mutations, p.Arg1809Cys and a multi-exon deletion, providing genetic evidence that p.Arg1809Cys is a loss-of-function mutation in the melanocytes and causes a pigmentary phenotype. Constitutional missense mutations at p.Arg1809 affect 1.23% of unrelated NF1 probands in the UAB cohort, therefore this specific NF1 genotype-phenotype correlation will affect counseling and management of a significant number of patients
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