Improvements to PLSc: Remaining problems and simple solutions

The recent article by Dijkstra and Henseler (2015b) presents a consistent partial least squares (PLSc) estimator that corrects for measurement error attenuation and provides evidence showing that, generally, PLSc performs comparably to a wide variety of more conventional estimators for structural equation models (SEM) with latent variables. However, PLSc does not adjust for other limitations of conventional PLS, namely: (1) bias in estimates of regression coefficients due to capitalization on chance; and (2) overestimation of composite reliability due to the proportionality relation between factor loadings and indicator weights. In this article, we illustrate these problems and then propose a simple solution: the use of unit-weighted composites, rather than those constructed from PLS results, combined with errors-in-variables regression (EIV) by using reliabilities obtained from factor analysis. Our simulations show that these two improvements perform as well as or better than PLSc. We also provide examples of how our proposed estimator can be easily implemented in various proprietary and open source software packages

Cost-impact study of rotavirus vaccination programme in Scotland

Aim: In July 2013, the Scottish Government introduced a rotavirus vaccination programme into the childhood immunisation schedule. The aim of this research was to estimate the cost impact of this programme. Methods: Data for rotavirus-related resource use were identified including laboratory reports, hospitalisations, attendances at Accident and Emergency Departments, general practice consultations, calls to the National Health Service telephone helpline and prescriptions for common rehydration treatments. We used an interrupted time series analysis approach to assess the impact on resource utilisation in all categories. Appropriate costs were added to the models and predicted pre and post vaccination mean annual costs were estimated. The cost of the vaccination programme was estimated using costs from the literature. Results: The vaccination programme was associated with a reduction in utilisation in all measured healthcare resource categories. These reductions were all statistically significant (at the 95% level) with p-values less than 0.001. Reductions ranged from 18% in calls to NHS24 to 73% in positive laboratory reports. The vaccination programme was associated with a reduction in annual healthcare resource costs of 38% (£595,000 per 100,000 infants under five years old) in our measured categories (including £495,000 from a reduction in hospital stays). The annual overall cost-impact of the rotavirus vaccination programme (the cost of delivering the programme minus the reduction in resource costs) was estimated at approximately £435,000 per 100,000 infants under 5 years old. Conclusion: The rotavirus vaccination programme was associated with a reduction in all measured categories of rotavirus-related resource use by infants under 5 years old

Automatic correction of hand pointing in stereoscopic depth

In order to examine whether stereoscopic depth information could drive fast automatic correction of hand pointing, an experiment was designed in a 3D visual environment in which participants were asked to point to a target at different stereoscopic depths as quickly and accurately as possible within a limited time window (≤300 ms). The experiment consisted of two tasks: "depthGO" in which participants were asked to point to the new target position if the target jumped, and "depthSTOP" in which participants were instructed to abort their ongoing movements after the target jumped. The depth jump was designed to occur in 20% of the trials in both tasks. Results showed that fast automatic correction of hand movements could be driven by stereoscopic depth to occur in as early as 190 ms.This work was supported by the Grants from the National Natural Science Foundation of China (60970062 and 61173116) and the Doctoral Fund of Ministry of Education of China (20110072110014)

Exercise-induced laryngeal obstruction (EILO) in athletes: a narrative review by a subgroup of the IOC Consensus on 'acute respiratory illness in the athlete'

Exercise-induced laryngeal obstruction (EILO) is caused by paradoxical inspiratory adduction of laryngeal structures during exercise. EILO is an important cause of upper airway dysfunction in young individuals and athletes, can impair exercise performance and mimic lower airway dysfunction, such as asthma and/or exercise-induced bronchoconstriction. Over the past two decades, there has been considerable progress in the recognition and assessment of EILO in sports medicine. EILO is a highly prevalent cause of unexplained dyspnoea and wheeze in athletes. The preferred diagnostic approach is continuous visualisation of the larynx (via laryngoscopy) during high-intensity exercise. Recent data suggest that EILO consists of different subtypes, possibly caused via different mechanisms. Several therapeutic interventions for EILO are now in widespread use, but to date, no randomised clinical trials have been performed to assess their efficacy or inform robust management strategies. The aim of this review is to provide a state-of-the-art overview of EILO and guidance for clinicians evaluating and treating suspected cases of EILO in athletes. Specifically, this review examines the pathophysiology of EILO, outlines a diagnostic approach and presents current therapeutic algorithms. The key unmet needs and future priorities for research in this area are also covered.publishedVersio

Marketing or methodology? Exposing the fallacies of PLS with simple demonstrations

Purpose Over the past 20 years, partial least squares (PLS) has become a popular method in marketing research. At the same time, several methodological studies have demonstrated problems with the technique but have had little impact on its use in marketing research practice. This study aims to present some of these criticisms in a reader-friendly way for non-methodologists. Design/methodology/approach Key critiques of PLS are summarized and demonstrated using existing data sets in easily replicated ways. Recommendations are made for assessing whether PLS is a useful method for a given research problem. Findings PLS is fundamentally just a way of constructing scale scores for regression. PLS provides no clear benefits for marketing researchers and has disadvantages that are features of the original design and cannot be solved within the PLS framework itself. Unweighted sums of item scores provide a more robust way of creating scale scores. Research limitations/implications The findings strongly suggest that researchers abandon the use of PLS in typical marketing studies. Practical implications This paper provides concrete examples and techniques to practicing marketing and social science researchers regarding how to incorporate composites into their work, and how to make decisions regarding such. Originality/value This work presents a novel perspective on PLS critiques by showing how researchers can use their own data to assess whether PLS (or another composite method) can provide any advantage over simple sum scores. A composite equivalence index is introduced for this purpose

Pharmacologically Distinct Nicotinic Acetylcholine Receptors Drive Efferent-Mediated Excitation in Calyx-Bearing Vestibular Afferents

Electrical stimulation of vestibular efferent neurons rapidly excites the resting discharge of calyx/dimorphic (CD) afferents. In turtle, this excitation arises when acetylcholine (ACh), released from efferent terminals, directly depolarizes calyceal endings by activating nicotinic ACh receptors (nAChRs). Although molecular biological data from the peripheral vestibular system implicate most of the known nAChR subunits, specific information about those contributing to efferent-mediated excitation of CD afferents is lacking. We sought to identify the nAChR subunits that underlie the rapid excitation of CD afferents and whether they differ from α9α10 nAChRs on type II hair cells that drive efferent-mediated inhibition in adjacent bouton afferents. We recorded from CD and bouton afferents innervating the turtle posterior crista during electrical stimulation of vestibular efferents while applying several subtype-selective nAChR agonists and antagonists. The α9α10 nAChR antagonists, α-bungarotoxin and α-conotoxin RgIA, blocked efferent-mediated inhibition in bouton afferents while leaving efferent-mediated excitation in CD units largely intact. Conversely, 5-iodo-A-85380, sazetidine-A, varenicline, α-conotoxin MII, and bPiDDB (N,N-dodecane-1,12-diyl-bis-3-picolinium dibromide) blocked efferent-mediated excitation in CD afferents without affecting efferent-mediated inhibition in bouton afferents. This pharmacological profile suggested that calyceal nAChRs contain α6 and β2, but not α9, nAChR subunits. Selective blockade of efferent-mediated excitation in CD afferents distinguished dimorphic from calyx afferents by revealing type II hair cell input. Dimorphic afferents differed in having higher mean discharge rates and a mean efferent-mediated excitation that was smaller in amplitude yet longer in duration. Molecular biological data demonstrated the expression of α9 in turtle hair cells and α4 and β2 in associated vestibular ganglia

Galaxy evolution by color-log(n) type since redshift unity in the Hubble Ultra Deep Field

We explore the use of the color-log(n) plane (where n is the global Sersic index) as a tool for subdividing the high redshift galaxy population in a physically-motivated manner. Using a series of volume-limited samples out to z=1.5 in the Hubble Ultra Deep Field (UDF) we confirm the correlation between color-log(n) plane position and visual morphology observed locally and in other high redshift studies in the color and/or structure domain. Via comparison to a low redshift sample from the Millennium Galaxy Catalogue we quantify evolution by color-log(n) type, accounting separately for the specific selection and measurement biases against each. Specifically, we measure decreases in B-band surface brightness of 1.57 +/- 0.22 mag/sq.arcsec and 1.65 +/- 0.22 mag/sq.arcsec for `blue, diffuse' and `red, compact' galaxies respectively between redshift unity and the present day.Comment: 12 pages, 6 figures, to be published in A&A (accepted 29/10/08

Diagnosis and management of nasal obstruction in the athlete : a narrative review by subgroup B of the IOC Consensus Group on “Acute Respiratory Illness in the Athlete”

Protection of the health of the athlete is required for high level sporting performance. Acute respiratory illness is the leading cause of illness and can compromise training and competition in athletes. To date the focus on respiratory health in athletes has largely been on acute upper respiratory infections and asthma/exercise induced bronchoconstriction (EIB), while nasal conditions have received less attention. The nose has several important physiological functions for the athlete. Nasal conditions causing obstruction to airflow can compromise respiratory health in the athlete, negatively affect quality of life and sleep, cause mouth breathing and ultimately leading to inadequate recovery and reduced exercise performance. Nasal obstruction can be broadly classified as structural (static or dynamic) or mucosal. Mucosal inflammation in the nose (rhinitis) is the most frequent cause of nasal obstruction and is reported to be higher in athletes (21-74%) than in the general population (20-25%). This narrative review provides the sport and exercise medicine physician with a clinical approach to the diagnosis and management of common nasal conditions that can cause nasal obstruction, ultimately leading to improved athlete health and better sports performance.IOC Research Center (South Africa)http://www.minervamedica.it/it/riviste/sports-med-physical-fitness/index.php2022-06-22hj2022Sports Medicin