1,428 research outputs found

    Quantifying the sensitivity of simulated climate change to model configuration

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    Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Climatic Change 3-4 (2009): 275-298, doi:10.1007/s10584-008-9494-x.This study used “factor separation” to quantify the sensitivity of simulated present and future surface temperatures and precipitation to alternative regional climate model physics components. The method enables a quantitative isolation of the effects of using each physical component as well as the combined effect of two or more components. Simulation results are presented from eight versions of the Mesoscale Modeling System Version 5 (MM5), one-way nested within one version of the Goddard Institute for Space Studies Atmosphere-Ocean Global Climate Model (GISS AOGCM). The MM5 simulations were made at 108 km grid spacing over the continental United States for five summers in the 1990s and 2050s. Results show that the choice of cumulus convection parameterization is the most important “factor” in the simulation of contemporary surface summer temperatures and precipitation over both the western and eastern United States. The choice of boundary layer scheme and radiation package also increases the range of model simulation results. Moreover, the alternative configurations give quite different results for surface temperature and precipitation in the 2050s. For example, simulated 2050s surface temperatures by the scheme with the coolest 1990s surface temperatures are comparable to 1990s temperatures produced by other schemes. The study analyzes the spatial distribution of 1990s to 2050s projected changes in the surface temperature for the eight MM5 versions. The predicted surface temperature change at a given grid point, averaged over all eight model configurations, is generally about twice the standard deviation of the eight predicted changes, indicating relative consensus among the different model projections. Factor separation analysis indicates that the choice of cumulus parameterization is the most important modeling factor amongst the three tested contributing to the computed 1990s to 2050s surface temperature change, although enhanced warming over many areas is also attributable to synergistic effects of changing all three model components. Simulated ensemble mean precipitation changes, however, are very small and generally smaller than the inter-model standard deviations. The MM5 versions therefore offer little consensus regarding 1990s to 2050s changes in precipitation rates.This research was supported by Grant R828733 from the U.S. Environmental Protection Agency's Science to Achieve Results (STAR) program, NSF Grant ATM-0652518, NASA Grant NNX07AI93G and the NASA Climate Variability and Climate Change Programs

    The Jefferson Scale of Empathy: a nationwide study of measurement properties, underlying components, latent variable structure, and national norms in medical students.

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    The Jefferson Scale of Empathy (JSE) is a broadly used instrument developed to measure empathy in the context of health professions education and patient care. Evidence in support of psychometrics of the JSE has been reported in health professions students and practitioners with the exception of osteopathic medical students. This study was designed to examine measurement properties, underlying components, and latent variable structure of the JSE in a nationwide sample of first-year matriculants at U.S. colleges of osteopathic medicine, and to develop a national norm table for the assessment of JSE scores. A web-based survey was administered at the beginning of the 2017-2018 academic year which included the JSE, a scale to detect good impression responses, and demographic/background information. Usable surveys were received from 6009 students enrolled in 41 college campuses (median response rate = 92%). The JSE mean score and standard deviation for the sample were 116.54 and 10.85, respectively. Item-total score correlations were positive and statistically significant (p \u3c 0.01), and Cronbach α = 0.82. Significant gender differences were observed on the JSE scores in favor of women. Also, significant differences were found on item scores between top and bottom third scorers on the JSE. Three factors of Perspective Taking, Compassionate Care, and Walking in Patient\u27s Shoes emerged in an exploratory factor analysis by using half of the sample. Results of confirmatory factor analysis with another half of the sample confirmed the 3-factor model. We also developed a national norm table which is the first to assess students\u27 JSE scores against national data

    Clinical Perspectives on Incorporating Cardiorespiratory Fitness in Clinical Practice

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    Cardiorespiratory fitness (CRF) has been documented as a strong, independent predictor of non-communicable disease and mortality in both clinical and apparently healthy populations. This well-established relationship has impelled organizations, including the American Heart Association, to release scientific statements highlighting the importance of accurate quantification of CRF. Current knowledge of the relationship between CRF and mortality is predominantly based on estimated CRF obtained from varying indirect methods. Cardiopulmonary exercise testing (CPX), the gold standard method of CRF measurement, provides a more accurate and reliable quantification of CRF compared to estimated methods. This review provides support for the diagnostic and prognostic use of CRF based on the current literature and makes a case for the use of CPX when available, as well as the need for standardization of normative values defining CRF levels to increase the efficacy of the risk assessment. Further, clinical applications of CPX-derived CRF are discussed, providing clinicians with recommendations on how to use and interpret this measure in practice to guide clinical decisions and improve patient outcomes

    Attitudes toward osteopathic medicine scale: development and psychometrics

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    Objective: To develop a valid and reliable instrument for measuring attitudes toward osteopathic medicine. Methods: Participants included 5,669 first-year students from 33 U.S. colleges of osteopathic medicine, who completed an online survey at the beginning of the 2019-2020 academic year. Using data from the nationwide Project in Osteopathic Medical Education and Empathy, we developed a 13-item instrument: Attitudes Toward Osteopathic Medicine Scale (ATOMS) and demonstrated the validity and reliability of its scores. The social desirability response bias was controlled in statistical analyses. Results: The corrected item-total score correlations were all positive and statistically significant, and the effect sizes of item discrimination indices were large. Cronbach\u27s coefficient alpha reliability was 0.83. Construct validity, corroborating face and content validity of the ATOMS, was supported by three components, emerged from factor analysis: Perspectives on Osteopathic Medicine, Osteopathic Diagnosis and Treatment, and Holistic-Integrative Care. Correlations between ATOMS scores and scores of cognitive empathy, emotional empathy; orientation toward interprofessional collaboration; lifelong learning; and burnout were statistically significant in the expected direction, providing validity evidence for the ATOMS. Using the method of contrasted groups, significant differences in the ATOMS scores were found by gender, ethnicity, academic background, and career interest in the expected direction, supporting the validity of the ATOMS scores. National norms were developed to assess individual scores alongside national percentile ranks. Conclusions: The ATOMS, developed in a nationwide study, supported by strong psychometric evidence for measuring orientation toward osteopathic medicine, has implications for the assessment of osteopathic medical education, patient outcomes, and admission decisions

    Feasibility and tolerability of multimodal peripheral electrophysiological techniques in a cohort of patients with spinal muscular atrophy

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    Objective: Electrophysiological techniques are emerging as an aid in identifying prognostic or therapeutic biomarkers in patients with spinal muscular atrophy (SMA), but electrophysiological assessments may be burdensome for patients. We, therefore, assessed feasibility and tolerability of multimodal peripheral non-invasive electrophysiological techniques in a cohort of patients with SMA. Methods: We conducted a single center, longitudinal cohort study investigating the feasibility and tolerability of applying multimodal electrophysiological techniques to the median nerve unilaterally. Techniques consisted of the compound muscle action potential scan, motor nerve excitability tests, repetitive nerve stimulation and sensory nerve action potential. We assessed tolerability using the numeric rating scale (NRS), ranging from 0 (no pain) to 10 (worst possible pain), and defined the protocol to be tolerable if the NRS score ≤ 3. The protocol was considered feasible if it could be performed according to test and quality standards. Results: We included 71 patients with SMA types 1–4 (median 39 years; range 13–67) and 63 patients at follow-up. The protocol was feasible in 98% of patients and was well-tolerated in up to 90% of patients. Median NRS score was 2 (range 0–6 at baseline and range 0–4 at follow-up (p < 0.01)). None of the patients declined follow-up assessment. Conclusions: Multimodal, peripheral, non-invasive, electrophysiological techniques applied to the median nerve are feasible and well-tolerated in adolescents and adults with SMA types 1–4. Significance: Our study supports the use of non-invasive multimodal electrophysiological assessments in adolescents and adults with SMA types 1–4

    Quantitative assessment of brachial plexus MRI for the diagnosis of chronic inflammatory neuropathies

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    OBJECTIVE: This study aimed at developing a quantitative approach to assess abnormalities on MRI of the brachial plexus and the cervical roots in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) and to evaluate interrater reliability and its diagnostic value. METHODS: We performed a cross-sectional study in 50 patients with CIDP, 31 with MMN and 42 disease controls. We systematically measured cervical nerve root sizes on MRI bilaterally (C5, C6, C7) in the coronal [diameter (mm)] and sagittal planes [area (mm2)], next to the ganglion (G0) and 1 cm distal from the ganglion (G1). We determined their diagnostic value using a multivariate binary logistic model and ROC analysis. In addition, we evaluated intra- and interrater reliability. RESULTS: Nerve root size was larger in patients with CIDP and MMN compared to controls at all predetermined anatomical sites. We found that nerve root diameters in the coronal plane had optimal reliability (intrarater ICC 0.55-0.87; interrater ICC 0.65-0.90). AUC was 0.78 (95% CI 0.69-0.87) for measurements at G0 and 0.81 (95% CI 0.72-0.91) for measurements at G1. Importantly, our quantitative assessment of brachial plexus MRI identified an additional 10% of patients that showed response to treatment, but were missed by nerve conduction (NCS) and nerve ultrasound studies. CONCLUSION: Our study showed that a quantitative assessment of brachial plexus MRI is reliable. MRI can serve as an important additional diagnostic tool to identify treatment-responsive patients, complementary to NCS and nerve ultrasound

    Cognitive Information Processing

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    Contains goals, background, research activities on one research project and reports on three research projects.Center for Advanced Television StudiesAmerican Broadcasting CompanyAmpex CorporationColumbia Broadcasting SystemsHarris CorporationHome Box OfficePublic Broadcasting ServiceNational Broadcasting CompanyRCA CorporationTektronix3M CompanyProvidence Gravure Co. (Grant)International Business Machines, Inc

    In silico modeling indicates the development of HIV-1 resistance to multiple shRNA gene therapy differs to standard antiretroviral therapy

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    <p>Abstract</p> <p>Background</p> <p>Gene therapy has the potential to counter problems that still hamper standard HIV antiretroviral therapy, such as toxicity, patient adherence and the development of resistance. RNA interference can suppress HIV replication as a gene therapeutic via expressed short hairpin RNAs (shRNAs). It is now clear that multiple shRNAs will likely be required to suppress infection and prevent the emergence of resistant virus.</p> <p>Results</p> <p>We have developed the first biologically relevant stochastic model in which multiple shRNAs are introduced into CD34+ hematopoietic stem cells. This model has been used to track the production of gene-containing CD4+ T cells, the degree of HIV infection, and the development of HIV resistance in lymphoid tissue for 13 years. In this model, we found that at least four active shRNAs were required to suppress HIV infection/replication effectively and prevent the development of resistance. The inhibition of incoming virus was shown to be critical for effective treatment. The low potential for resistance development that we found is largely due to a pool of replicating wild-type HIV that is maintained in non-gene containing CD4+ T cells. This wild-type HIV effectively out-competes emerging viral strains, maintaining the viral <it>status quo</it>.</p> <p>Conclusions</p> <p>The presence of a group of cells that lack the gene therapeutic and is available for infection by wild-type virus appears to mitigate the development of resistance observed with systemic antiretroviral therapy.</p
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