Observed correlations from cross-sectional individual differences research reflect both between-person and within-person correlations

The study of individual differences is often conducted using cross-sectional experiments. The cross-sectional nature of such data means that results obtained from these experiments are a mix of both between- and within-person associations. While concerns about this within-between confounding effect have been surfaced, they are often not addressed when reporting results from individual differences studies. This obfuscation threatens the interpretability and validity of cross-sectional individual differences research. We speculate that a lack of a clear and accessible description of the confounding effect may have contributed to the limited attention to this issue. In this paper, we develop a tractable description of the confounding effect and how it manifests. In doing so, we suggest a need for greater transparency in the reporting of the goals and results of cross-sectional studies and how they contribute to knowledge of individual differences.

When Taekwondo Referees See Red, but It Is an Electronic System That Gives the Points

Previous studies in taekwondo have considered the use of the manual scoring system or the electronic system with only the use of the electronic body protector. The objective of this study was to analyze the relationship between the color protectors and success in 1,327 taekwondo matches from six World Grand Prix Series of two 4-year Olympic periods when electronic body and head protectors are used. In the total sample, the results did not show a relationship between the match outcome and the color of the protectors (p = 0.97, C = 0.001). For the individual six editions, the results showed a positive and strong relationship between wearing blue protectors and winning matches and one between wearing red protectors and winning matches (p = 0.001, C = 0.19; p = 0.001; C = 0.19). Regarding the weight categories, 8 and 5 of 48 showed higher percentages of blue and red winners, respectively. Regarding sex, male competitors showed a positive relationship between blue color and winning the match in 6 of 24 weight categories, and wearing red and winning the match was shown in 2 of 24 weight categories. Female competitors showed a positive relationship between blue color and winning the match in 2 of 24 weight categories, and wearing red and winning the match was shown in 3 of 24 weight categories. When it comes to the influence of being a seeded athlete, the results did show a significant confounding effect on the color of the protectors worn by the winner of the match in 2 of 13 weight categories in which a color effect was observed (p = 0.02, C = 0.28; p = 0.02, C = 0.28). In conclusion, wearing red does not provide a higher chance of winning the match. It seems that seeing red has a stronger effect than wearing red, especially in male contenders. Moreover, being a seeded athlete does not explain the result of the match. It seems that the introduction of the electronic helmet protector, in addition to the electronic body protector, made the scoring system more objective, decreasing the advantage of wearing red in winning matches.

Does Latent Tuberculosis Lead to a Spurious Correlation between BCG and COVID-19 Mortality?

Background: Many factors have been suggested to confound coronavirus disease 2019 (COVID-19) studies, and BCG studies have been criticized for not adjusting for many confounders. We conducted this study to analyze the presumed effectiveness of the Bacillus Calmette–Guérin (BCG) vaccine in decreasing the COVID-19 mortality rate, and to answer the question of whether this is confounded by latent tuberculosis (LTB) prevalence.Materials and methods: We chose sixty-nine malaria-free countries with different BCG vaccination policies. TB prevalence was considered as a proxy for LTB. The BCG, TB prevalence, and COVID-19 mortality data are publically available. Contingency coefficients (C.C.) and a ROC analysis were used to assess the relationship between TB prevalence and BCG status, and identify cutoff points in each BCG group category. A stem–leaf plot was also used to explore the data’s apparent behavior concerning COVID-19 in relation to the BCG groups.Results: TB prevalence was significantly associated with BCG status. The BCG vaccination status apparently had a relationship with BCG status.Conclusions: TB is suggested to have a confounding effect on BCG results, leading to a spurious correlation between BCG and COVID-19 mortality.

Persistence of perennial ryegrass, tall fescue and cocksfoot following annual sowings: influence of grass species, ryegrass cultivar and pasture age on yield, composition and density

Persistence is an important component of perennial pasture-grass productivity. Defining traits that affect persistence is essential for improving pasture longevity through plant breeding and for identifying persistence traits that should be included in cultivar ranking indices. Compared with conventional longitudinal studies, where a single sowing is monitored over time, repeated annual sowings allow the effects on persistence of sowing year and the ensuing interactions between environment and age of pasture to be identified. An experiment was commenced in 2015 under sheep grazing in Canterbury and in 2016 under cattle grazing in Waikato, where eight cultivars of perennial ryegrass representing different ploidy, flowering date, and cultivar age (release date), and one cultivar each of tall fescue and cocksfoot were sown in four randomised complete blocks in autumn each year. This paper reports interim data on spring and autumn pasture yield, composition, and density of 3-year-old, 2-year-old and 1-year-old pastures exposed to the same environmental conditions within the same, single year. There were significant effects on yield, botanical composition, basal cover and tiller density due to cultivar, pasture age, and their interaction. When the confounding effect of year-to-year variation was removed by comparing each age cohort in the same year, the underlying differences among grass species and cultivars, and ages of pasture, is starting to reveal the nature of this influence on pasture persistence.

A standardized gnotobiotic mouse model harboring a minimal 15-member mouse gut microbiota recapitulates SOPF/SPF phenotypes

Mus musculus is the classic mammalian model for biomedical research. Despite global efforts to standardize breeding and experimental procedures, the undefined composition and interindividual diversity of the microbiota of laboratory mice remains a limitation. In an attempt to standardize the gut microbiome in preclinical mouse studies, here we report the development of a simplified mouse microbiota composed of 15 strains from 7 of the 20 most prevalent bacterial families representative of the fecal microbiota of C57BL/6J Specific (and Opportunistic) Pathogen-Free (SPF/SOPF) animals and the derivation of a standardized gnotobiotic mouse model called GM15. GM15 recapitulates extensively the functionalities found in the C57BL/6J SOPF microbiota metagenome, and GM15 animals are phenotypically similar to SOPF or SPF animals in two different facilities. They are also less sensitive to the deleterious effects of post-weaning malnutrition. In this work, we show that the GM15 model provides increased reproducibility and robustness of preclinical studies by limiting the confounding effect of fluctuation in microbiota composition, and offers opportunities for research focused on how the microbiota shapes host physiology in health and disease.

Translation of Preclinical PET Imaging Findings: Challenges and Motion Correction to Overcome the Confounding Effect of Anesthetics

Preclinical brain positron emission tomography (PET) in animals is performed using anesthesia to avoid movement during the PET scan. In contrast, brain PET scans in humans are typically performed in the awake subject. Anesthesia is therefore one of the principal limitations in the translation of preclinical brain PET to the clinic. This review summarizes the available literature supporting the confounding effect of anesthesia on several PET tracers for neuroscience in preclinical small animal scans. In a second part, we present the state-of-the-art methodologies to circumvent this limitation to increase the translational significance of preclinical research, with an emphasis on motion correction methods. Several motion tracking systems compatible with preclinical scanners have been developed, each one with its advantages and limitations. These systems and the novel experimental setups they can bring to preclinical brain PET research are reviewed here. While technical advances have been made in this field, and practical implementations have been demonstrated, the technique should become more readily available to research centers to allow for a wider adoption of the motion correction technique for brain research.

O-058 The impact of endometriosis on fertility treatment

Abstract text Endometriosis can affect natural fertility by distorting pelvic anatomy and by causing local pelvic inflammation that affects the quality of the oocytes, the function of the tubes and the sperm capacity to fertilize. Two approaches can be foreseen, either removing the disease with the aim of restoring normality (surgery) or overcoming the disease by retrieving oocytes in the ovary and allowing their fertilization in in vitro conditions (IVF). Both therapeutic approaches seem rational and wise. However, despite this apparently simple clinical scenario, management of endometriosis-related infertility has engendered long-lasting and burning debates over the last two decades and, to date, no consensus has been reached. Robust scientific evidence is scant, actually limited to the demonstration that laparoscopy modestly increases the chance of natural conception. In this debate, it is noteworthy that chances of pregnancy do not represent the unique stake. Other factors can play a role and deserves consideration. Considering the choice of fertility treatment, he most relevant are the following: 1) the impact of ovarian endometriomas and their removal on ovarian responsiveness, 2) the impact of endometriomas and endometriosis in general on oocytes quality, 3) the additional risks of oocytes retrieval in the presence of endometriosis (infections in particular) 4) the detrimental effects of endometriosis-related hydrosalpinx, 5) the impact of endometriosis on uterine motility and endometrial receptivity, 5) the confounding effect of endometriosis-associated adenomyosis. Unfortunately, for the vast majority of these concerns, evidence is not definite and physicians have to take decisions based on their clinical commonsense.

In-phase and in-antiphase connectivity in EEG

Zero-lag synchrony is generally discarded from functional connectivity studies to eliminate the confounding effect of volume conduction. Demonstrating genuine and significant unlagged synchronization between distant brain regions would indicate that most electroencephalography (EEG) connectivity studies neglect an important mechanism for neuronal communication. We previously demonstrated that local field potentials recorded intracranially tend to synchronize with no lag between homotopic brain regions. This synchrony occurs most frequently in antiphase, potentially supporting corpus callosal inhibition and interhemispheric rivalry. We are now extending our investigation to EEG. By comparing the coherency in a recorded and a surrogate dataset, we confirm the presence of a significant proportion of genuine zero-lag synchrony unlikely to be due to volume conduction or to recording reference artifacts. These results stress the necessity for integrating zero-lag synchrony in our understanding of neural communication and for disentangling volume conduction and zero-lag synchrony when estimating EEG sources and their functional connectivity.