scholarly journals A Systematic Review of Methods and Criteria Standard Proposal for the Use of Principal Component Analysis in Team’s Sports Science

Author(s):  
Daniel Rojas-Valverde ◽  
José Pino-Ortega ◽  
Carlos D. Gómez-Carmona ◽  
Markel Rico-González

The availability of critical information about training and competition is fundamental on performance. Principal components analysis (PCA) is widely used in sports as a multivariate technique to manage big data from different technological assessments. This systematic review aimed to explore the methods reported and statistical criteria used in team’s sports science and to propose a criteria standard to report PCA in further applications. A systematic electronic search was developed through four electronic databases and a total of 45 studies were included in the review for final analysis. Inclusion criteria: (i) of the studies we looked at, 22.22% performed factorability processes with different retention criteria (r > 0.4–0.7); (ii) 21 studies confirmed sample adequacy using Kaiser-Meyer-Olkim (KMO > 5–8) and 22 reported Bartlett’s sphericity; (iii) factor retention was considered if eigenvalues >1–1.5 (n = 29); (iv) 23 studies reported loading retention (>0.4–0.7); and (v) used VariMax as the rotation method (48.9%). A lack of consistency and serious voids in reporting of essential methodological information was found. Twenty-one items were selected to provide a standard quality criterion to report methods sections when using PCA. These evidence-based criteria will lead to a better understanding and applicability of the results and future study replications.

2020 ◽  
Vol 25 (2) ◽  
pp. 67-81
Author(s):  
Ljiljana Najev Čačija ◽  
Davorka Mikulić ◽  
Daša Dragnić

This study presents a preliminary research towards a conceptual model of relationship between the overall and the destination attributes satisfaction. Precisely, the paper explores and classifies destination pull factors as a precondition to design a conceptual model. Therefore, the first step was to categorise destination attributes into meaningful groups of pull factors that provide greater efficiency in achieving and maintaining a desired perception of destination quality, measured by tourists’ satisfaction. The exploratory factor analysis was conducted on the sample of 289 tourists visiting the town of Split (Croatia). The required prior statistical preconditions were successfully met and the principal component analysis was conducted on 20 items with Varimax rotation method. Based on the results, four pull factors were retained in the final analysis, explaining 54.760% of the variance. In the final categorisation, factor loading was above 0.4 for all four extracted factors, with reliability of measurement scales. Major findings of this study confirm that destination attributes can be grouped in a meaningful way regarding tourist satisfaction and indicate that the extracted pull factors, representing both common and unique destination attributes, have the potential to be generally applicable. The extracted factors are the primary or fundamental offer components; additional/expanded offer components; tertiary or tendency/affinity/preference offer components and specific offer components. Recommendations for further research are given, in order to explore to what extent the tourists’ overall satisfaction is related to their satisfaction with destination attributes, and to expand the model with the impact of other moderating elements.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1067.1-1067
Author(s):  
S. Hecquet ◽  
P. Totoson ◽  
H. Martin ◽  
C. Prati ◽  
D. Wendling ◽  
...  

Background:Growing evidence argue for a role of the gut in the pathophysiology of various chronic rheumatic diseases such as spondyloarthritis (SpA). This so-called “gut-joint axis” involves dysbiosis, bacterial translocation, intestinal inflammation and increase in intestinal permeability. Recent data from clinical and basic research suggested that the integrity of the intestinal barrier might be a key determinant in translating autoimmunity to inflammation, making intestinal permeability a potential marker or a target for future therapies.Objectives:To analyse the available data on intestinal permeability in SpA patients and the effects of drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) on intestinal permeability.Methods:A systematic review was conducted. Without date restriction, the following databases were searched through September 1, 2020: Medline, Embase and Cochrane. Studies with patients with SpA assessing the intestinal permeability were selected. Some of the included studies have assessed the effect of NSAIDs on intestinal permeability.Results:A total of 12 studies were included in the final analysis. The 12 studies involved a total of 268 SpA patients, including 240 ankylosing spondylitis (AS). Among the studies included, four studies used the lactulose/mannitol test, four studies used the 51Cr-ethylenediaminetetraacetic test and two studies used the polyethylene glycols test. Nine of the 12 studies reported increased intestinal permeability regardless on the method used for intestinal permeability evaluation. Four studies evaluated the link between disease activity, assessed by CRP and ESR levels, and intestinal permeability and showed no correlation between increased intestinal permeability and markers of disease activity in AS patients. As regards the effects of NSAIDs on intestinal permeability, data are controversial. Two studies, including one evaluating indomethacin, did not show any influence of NSAIDs in AS patients, one study showed an increase in intestinal permeability under NSAIDs in only 60% of the patients, another study reported increased intestinal permeability. When comparing the effect of NSAIDs in patients with AS to healthy subjects, one study reported a comparable NSAIDs-induced increase in intestinal permeability in both groups.Conclusion:The results of our review suggest that increased intestinal permeability is present in SpA patients even in the absence of NSAIDs use and regardless of the method used to assess intestinal permeability. The effects of NSAIDs on intestinal permeability in SpA patients is more controversial and further studies are needed to clarify them.Disclosure of Interests:None declared


2021 ◽  
Vol 06 (01) ◽  
pp. e35-e39
Author(s):  
Chelsi Robertson ◽  
Charles Patterson ◽  
Hugo St. Hilaire ◽  
Frank H. Lau

Abstract Background Pressure ulcers (PUs) affect 2.5 million people in the United States annually and incur health-care costs of 11 billion dollars annually. Stage III/IV PU often require local flap reconstruction. Unfortunately, PU recurrence is common following reconstruction; recurrence rates as high as 82% have been reported. When local flap options are inadequate, free tissue transfer may be indicated but the indications have yet to be delineated. To develop evidence-based guidelines for the use of free flaps in PU reconstruction, we performed a systematic review. Methods A systematic review of the available English-language, peer-reviewed literature was conducted using PubMed/MEDLINE, Google Scholar, Scopus, EMBASE, and the Cochrane Database of Systematic Reviews. Articles were manually reviewed for relevance. Results Out of 272 articles identified, 10 articles were included in the final analysis. Overall, this systematic review suggests that free-flap PU reconstruction yields fewer recurrences compared with local flaps (0–20 vs. 13–82%). Further, several types of free flaps for PU reconstruction were identified in this review, along with their indications. Conclusion Free tissue transfer should be considered for recurrent PU. We offer specific recommendations for their use in PU reconstruction.


2021 ◽  
pp. 000370282098784
Author(s):  
James Renwick Beattie ◽  
Francis Esmonde-White

Spectroscopy rapidly captures a large amount of data that is not directly interpretable. Principal Components Analysis (PCA) is widely used to simplify complex spectral datasets into comprehensible information by identifying recurring patterns in the data with minimal loss of information. The linear algebra underpinning PCA is not well understood by many applied analytical scientists and spectroscopists who use PCA. The meaning of features identified through PCA are often unclear. This manuscript traces the journey of the spectra themselves through the operations behind PCA, with each step illustrated by simulated spectra. PCA relies solely on the information within the spectra, consequently the mathematical model is dependent on the nature of the data itself. The direct links between model and spectra allow concrete spectroscopic explanation of PCA, such the scores representing ‘concentration’ or ‘weights’. The principal components (loadings) are by definition hidden, repeated and uncorrelated spectral shapes that linearly combine to generate the observed spectra. They can be visualized as subtraction spectra between extreme differences within the dataset. Each PC is shown to be a successive refinement of the estimated spectra, improving the fit between PC reconstructed data and the original data. Understanding the data-led development of a PCA model shows how to interpret application specific chemical meaning of the PCA loadings and how to analyze scores. A critical benefit of PCA is its simplicity and the succinctness of its description of a dataset, making it powerful and flexible.


2021 ◽  
pp. 036354652199801
Author(s):  
Michael R. Baria ◽  
W. Kelton Vasileff ◽  
James Borchers ◽  
Alex DiBartola ◽  
David C. Flanigan ◽  
...  

Background: Platelet-rich plasma (PRP) and hyaluronic acid (HA) are injectable treatments for knee osteoarthritis. The focus of previous studies has compared their efficacy against each other as monotherapy. However, a new trend of combining these 2 injections has emerged in an attempt to have a synergistic effect. Purpose: To systematically review the clinical literature examining the combined use of PRP + HA. Design: Systematic review. Methods: A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed and Embase. The following search terms were used: knee osteoarthritis AND platelet rich plasma AND hyaluronic acid. The review was performed by 2 independent reviewers who applied the inclusion/exclusion criteria and independently extracted data, including methodologic scoring, PRP preparation technique, HA composition, and patient-reported outcomes (PROs). Results: A total of 431 articles were screened, 12 reviewed in full, and 8 included in the final analysis: 2 case series, 3 comparative, and 3 randomized studies. Average follow-up was 9 months. The modified Coleman Methodology Score was 38.13 ± 13.1 (mean ± SD). Combination therapy resulted in improved PROs in all studies. Of the comparative and randomized studies, 2 demonstrated that combination therapy was superior to HA alone. However, when PRP alone was used as the control arm (4 studies), combination therapy was not superior to PRP alone. Conclusion: Combination therapy with PRP + HA improves PROs and is superior to HA alone but is not superior to PRP alone.


2021 ◽  
Vol 13 (13) ◽  
pp. 7397
Author(s):  
Isabel Blanco-Penedo ◽  
Javier García-Gudiño ◽  
Elena Angón ◽  
José Manuel Perea ◽  
Alfredo J. Escribano ◽  
...  

The aim of the present study was (1) to investigate what consumers include within the concept of food sustainability and its link with sustainable consumption, by identifying meaningful consumer typologies from the concept of food sustainability and food choice factors framed by SDG 12, and (2) to know how different farm systems attributes affecting purchase behavior are associated with such typologies. Consumers from two Spanish regions (n = 403) answered a paper questionnaire to know their degree of knowledge of sustainability, and beliefs, behavior, attitudes and preferences towards food sustainability, and the importance given to product characteristics and shopping practices. A principal component analysis was conducted to identify groups with similar answers, to average some of the questions before the final analysis of variance, which includes demographic classes as fixed effects. A cluster analysis using the most representative questions identified two clusters. cluster 1 (68.4%) responded to more sustainability-related attributes, and cluster 2 (31.5%) presented a less-expanded concept of sustainability. The origin of the product and quality certification (local, organic) was important for food purchase practices. The place of residence and gender differences of the consumers were the most influential factors. In the conjoint study, regarding the purchase of Iberian pork, cluster 1 remained unwilling to sacrifice outdoor systems and local breed at the expense of the price, in the case of the Iberian pig production. The most important demographic differentiator was the region of residence of the consumer. In conclusion, consumers are not aware of the wider aspects included in the sustainability concept. Moreover, the concept of sustainability elicits different meanings to the segments of the consumers identified.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S787-S787
Author(s):  
Tim Reason ◽  
Karan Gill ◽  
Christopher Longshaw ◽  
Rachael McCool ◽  
Katy Wilson ◽  
...  

Abstract Background Antimicrobial resistance is a major and growing threat to global public health. Cefiderocol (CFDC) is a new siderophore-cephalosporin with a wide activity spectrum covering all aerobic GN pathogens including all WHO critical priority pathogens, that was recently approved by FDA for the treatment of GN cUTI in susceptible organisms. We aim to understand the relative efficacy and safety of current treatment options for cUTI caused by MDR GN pathogens. Methods We conducted a systematic review to identify all relevant trials that investigated the efficacy and safety of antimicrobial regimens, for the treatment of GN pathogens in cUTI. Outcomes of interest included clinical cure and microbiological eradication (ME) at time of cure (TOC) and sustained follow up (SFU), and safety. Evidence networks were constructed using data for outcomes of interest and analyses were conducted in a frequentist framework using NMA methods outlined by the NICE decision support unit using the netmeta package in R. Results A total of 5 studies, 6 interventions and 2,349 randomised patients were included in the final analysis. Interventions included CFDC, imipenem-cilastatin (IPM-CIL), ceftazidime-avibactam (CAZ/AVI), doripenem (DOR), levofloxacin and ceftolozane-tazobactam (CEF/TAZ). Trials included predominantly Enterobacterales, and Pseudomonas aeruginosa and very few Acinetobacter baumannii. The patient population presented some clinical differences across trials, which were not adjusted for the NMA. Overall, there were numerical differences (especially in endpoints at SFU favouring CFDC), but all treatments showed similar efficacy and safety, with exception of higher ME rate at TOC for CFDC vs IPM, Table 1, also observed at SFU, consistent with the data from the individual clinical trial. Table 1- Results for microbiological eradication Table 1- Results for microbiological eradication Conclusion This NMA, showed superiority of CFDC vs IPM-CIL in ME at TOC and SFU and similar efficacy and safety vs all other comparators, with numeric differences favouring CFDC for outcomes at SFU. These traditional methodologies for NMA, are only valid within a similar pathogens pool and population across the trials, and may not reflect the full value of breadth of coverage that new therapeutic options bring for the treatment of MDR GN pathogens. Disclosures Tim Reason, PhD, Shionogi (Consultant) Karan Gill, MSc, Shionogi BV (Employee) Christopher Longshaw, PhD, Shionogi B.V. (Employee) Rachael McCool, PhD, York Health Economics Consortium (Employee, YHEC was commissioned by Shionogi to conduct the systematic review) Katy Wilson, PhD, York Health Economics Consortium (Employee, Shionogi commissioned YHEC to conduct the systematic review) Sara Lopes, PharmD, Shionogi BV (Employee)


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2423
Author(s):  
Michał Miłek ◽  
Aleksandra Bocian ◽  
Ewelina Kleczyńska ◽  
Patrycja Sowa ◽  
Małgorzata Dżugan

Many imported honeys distributed on the Polish market compete with local products mainly by lower price, which can correspond to lower quality and widespread adulteration. The aim of the study was to compare honey samples (11 imported honey blends and 5 local honeys) based on their antioxidant activity (measured by DPPH, FRAP, and total phenolic content), protein profile obtained by native PAGE, soluble protein content, diastase, and acid phosphatase activities identified by zymography. These indicators were correlated with standard quality parameters (water, HMF, pH, free acidity, and electrical conductivity). It was found that raw local Polish honeys show higher antioxidant and enzymatic activity, as well as being more abundant in soluble protein. With the use of principal component analysis (PCA) and stepwise linear discriminant analysis (LDA) protein content and diastase number were found to be significant (p < 0.05) among all tested parameters to differentiate imported honey from raw local honeys.


BMJ Open ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. e031598 ◽  
Author(s):  
Clare Meernik ◽  
Hannah M Baker ◽  
Sarah D Kowitt ◽  
Leah M Ranney ◽  
Adam O Goldstein

ObjectivesGiven the exponential increase in the use of e-cigarettes among younger age groups and in the growth in research on e-cigarette flavours, we conducted a systematic review examining the impact of non-menthol flavoured e-cigarettes on e-cigarette perceptions and use among youth and adults.DesignPubMed, Embase, PyscINFO and CINAHL were systematically searched for studies published and indexed through March 2018.Eligibility criteriaQuantitative observational and experimental studies that assessed the effect of non-menthol flavours in e-cigarettes on perceptions and use behaviours were included. Specific outcome measures assessed are appeal, reasons for use, risk perceptions, susceptibility, intention to try, initiation, preference, current use, quit intentions and cessation.Data extraction and synthesisThree authors independently extracted data related to the impact of flavours in tobacco products. Data from a previous review were then combined with those from the updated review for final analysis. Results were then grouped and analysed by outcome measure.ResultsThe review included 51 articles for synthesis, including 17 published up to 2016 and an additional 34 published between 2016 and 2018. Results indicate that non-menthol flavours in e-cigarettes decrease harm perceptions (five studies) and increase willingness to try and initiation of e-cigarettes (six studies). Among adults, e-cigarette flavours increase product appeal (seven studies) and are a primary reason many adults use the product (five studies). The role of flavoured e-cigarettes on smoking cessation remains unclear (six studies).ConclusionThis review provides summary data on the role of non-menthol flavours in e-cigarette perceptions and use. Consistent evidence shows that flavours attract both youth and adults to use e-cigarettes. Given the clear findings that such flavours increase product appeal, willingness to try and initiation among youth, banning non-menthol flavours in e-cigarettes may reduce youth e-cigarette use. Longitudinal research is needed to examine any role flavours may play in quit behaviours among adults.


2018 ◽  
Vol 6 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Akanksha Upadhyaya ◽  
Bhajneet Kaur

The aim of this research paper is to explore the electronic payment system (EPS) acceptability determinants, from the consumer perspective. Exploratory factor analysis has been used to explore the factors based on different statements. The study has been conducted in North-West region of Delhi. Data has been collected from male-female of different age groups by using the questionnaire tool of data collection. For extraction of factors Principal component analyses and Varimax with Kaiser Normalization rotation method was used. The rotated component matrix shows best fitting of items to form a factor. As per the convergence of items, 4 factors were extracted and named. These factors are security concern, Knowledge, awareness and acceptability & convenience which are contributing for acceptability of electronic payment system among the consumers.


Sign in / Sign up

Export Citation Format

Share Document