Calculating, Interpreting, And Reporting Cronbach’s Alpha Reliability Coefficient For Likert-Type Scales

The purpose of this paper is to show why single-item questions pertaining to a construct are not reliable and should not be used in drawing conclusions. By comparing the reliability of a summated, multi-item scale versus a single-item question, the authors show how unreliable a single item is; and therefore it is not appropriate to make inferences based upon the analysis of single-item questions which are used in measuring a construct

An Economic Evaluation of Emerging Variable Rate Application Technologies

Author Institution (Batte and Schnitkey): Department of Agricultural, Environmental and Developmental Economics, The Ohio State Universit

Isotopic Composition of Solar Wind Calcium: First in Situ Measurement by CELIAS/MTOF on Board SOHO

We present first results on the Ca isotopic abundances derived from the high resolution Mass Time-of-Flight (MTOF) spectrometer of the charge, element, and isotope analysis system (CELIAS) experiment on board the Solar and Heliospheric Observatory (SOHO). We obtain isotopic ratios 40Ca/42Ca = (128+-47) and 40Ca/44Ca = (50+-8), consistent with terrestrial values. This is the first in situ determination of the solar wind calcium isotopic composition and is important for studies of stellar modeling and solar system formation since the present-day solar Ca isotopic abundances are unchanged from their original isotopic composition in the solar nebula.Comment: 14 pages, 3 figure

Evaluation of coronary artery disease as a risk factor for reticular pseudodrusen

Purpose: Reticular pseudodrusen (RPD) are a risk factor for late age-related macular degeneration (AMD). Associations between RPD and coronary artery disease (CAD) have been reported from small case-control studies. This study investigated the association of RPD within a predominantly CAD cohort.Methods: A subgroup of subjects from a multicentre randomised controlled trial of CT coronary angiography (CTCA) underwent ultrawide field (UWF) retinal imaging CAD determined by CTCA and was categorised as normal, non-obstructive or obstructive. Specific AMD features in UWF images were graded. Standardised grids were used to record the spatial location of AMD features, including RPD. Multivariate confounder adjusted regression models assessed the association between RPD and CAD.Results: The 534 participants were aged 27-75 years (mean 58±9 years; 425 (80%) ≥50 years) with a male preponderance (56%). Within the study sample, 178 (33%) had no CAD, 351 (66%) had CAD. RPD was detected in 30 participants (5.6%) and bilaterally in 23. Most participants with bilateral RPD had intermediate AMD 17 (74%). After adjustment for potential confounders (age, sex, drusen &gt;125 µm, smoking status), multivariate analysis found no significant association between CAD and RPD (OR 1.31; 95% CI (0.57 to 3.01); p=0.52). A significant association was identified between RPD and intermediate AMD (OR 3.18; 95% CI (1.61 to 6.27); p=0.001).Conclusion: We found no evidence to support an association between CAD and RPD. RPD was strongly associated with intermediate AMD features.Trial Registration Number: NCT01149590, Post results.</p

Neural networks and dynamical systems

AbstractModels for the identification and control of nonlinear dynamical systems using neural networks were introduced by Narendra and Parthasarathy in 1990, and methods for the adjustment of model parameters were also suggested. Simulation results of simple nonlinear systems were presented to demonstrate the feasibility of the schemes proposed. The concepts introduced at that time are investigated in this paper in greater detail. In particular, a number of questions that arise when the methods are applied to more complex systems are addressed. These include nonlinear systems of higher order as well as multivariable systems. The effect of using simpler models for both identification and control are discussed, and a new controller structure containing a linear part in addition to a multilayer neural network is introduced

Comparison of the lossy image data compressions for the MESUR Pathfinder and for the Huygens Titan Probe

The commercial JPEG standard complies well with the specific requirements of exploratory space missions. Therefore, JPEG has been chosen to be the baseline for a series of spaceborne image data compressions (e.g. MARS94-HRSC, -WAOSS, HUYGENS-DISR, MESUR-IMP). One S/W-implementation (IMP) and one H/W-implementation (DISR) of image data compression are presented. Details of the modifications applied to standard JPEG are outlined. Finally, a performance comparison of the two implementations is given

Clinical Trial Simulation in Diabetic Retinopathy: Insights from Patients and Site Staff

Introduction: High patient burdens from diabetic retinopathy (DR)-associated vision loss and intravitreal therapy (IVT) support patient experience inclusion in DR trial designs. This trial simulation characterized patient and site staff opinions to improve future nonproliferative DR (NPDR) trial designs. Methods: Between March 27 and May 31, 2023, survey data were collected from trial simulation participants. After a preread and trial design animation, study features were simulated followed by a 75-90-min web-assisted telephone interview. Patients with NPDR and trial site staff from the United States, United Kingdom, and Germany were included. The likelihood of patient participation and the challenges faced by site staff in conducting the simulated clinical trial at their study site were assessed using a 1-7 scale. Outcomes were evaluated via thematic analysis and descriptive statistics. Results: Twenty-two patients aged 36-55&nbsp;years and mostly female (59.1%), and 16 site staff were interviewed. Mean NPDR duration was 9.3&nbsp;years; most patients (81.8%) had never participated in a clinical trial. Although eligibility criteria resembled other trials, site staff indicated that restrictive exclusion criteria of the trial simulation could limit recruitment and that endpoints did not match patients' goals, which mainly focused on saving vision. The proposed 4-5-h on-site visits and 72-week trial length were considered "too long" by 45.5% and 50.0% of patients, respectively. For the 1:2 sham or active treatment allocation ratio, responses were 40.9% neutral, 36.4% positive, and 22.7% negative. Some patients misunderstood that sham injections imitate actual injections, expressing concerns about adverse events. Patients reported IVT-related anxieties, particularly IVT-inexperienced patients. Mean patient trial participation interest score was 4.9/7; 62.5% of site staff were interested in conducting the trial. Some proposed adaptations were implemented in the trial protocol (e.g., offering patient/caregiver transportation). Conclusions: Insights gained from respondent feedback in this simulation may inform future DR clinical trial design, potentially enhancing recruitment rates and patient experience

Experimental stroke differentially affects discrete subpopulations of splenic macrophages

Changes to the immune system after stroke are complex and can result in both pro-inflammatory and immunosuppressive consequences. Following ischemic stroke, brain resident microglia are activated and circulating monocytes are recruited to the injury site. In contrast, there is a systemic deactivation of monocytes/macrophages that may contribute to immunosuppression and the high incidence of bacterial infection experienced by stroke patients. The manipulation of macrophage subsets may be a useful therapeutic strategy to reduce infection and improve outcome in patients after stroke. Recent research has enhanced our understanding of the heterogeneity of macrophages even within the same tissue. The spleen is the largest natural reservoir of immune cells, many of which are mobilized to the site of injury after ischemic stroke and is notable for the diversity of its functionally distinct macrophage subpopulations associated with specific micro-anatomical locations. Here, we describe the effects of experimental stroke in mice on these distinct splenic macrophage subpopulations. Red pulp (RP) and marginal zone macrophages (MZM) specifically showed increases in density and alterations in micro-anatomical location. These changes were not due to increased recruitment from the bone marrow but may be associated with increases in local proliferation. Genes associated with phagocytosis and proteolytic processing were upregulated in the spleen after stroke with increased expression of the lysosome-associated protein lysosomal-associated membrane proteins specifically increased in RP and MZM subsets. In contrast, MHC class II expression was reduced specifically in these populations. Furthermore, genes associated with macrophage ability to communicate with other immune cells, such as co-stimulatory molecules and inflammatory cytokine production, were also downregulated in the spleen after stroke. These findings suggest that selective splenic macrophage functions could be impaired after stroke and the contribution of macrophages to stroke-associated pathology and infectious complications should be considered at a subset-specific level. Therefore, optimal therapeutic manipulation of macrophages to improve stroke outcome is likely to require selective targeting of functionally and spatially distinct subpopulations