Measurement of swimming ability in larval marine fishes: comparison of critical speed with in situ speed

For much of their pelagic larval dispersal (PLD) stage, larval perciform fishes are able to directly influence their dispersal by horizontal swimming, but it is unclear which means of measuring swimming ability is most appropriate for modelling dispersal and studying demographic and genetic connectivity. Most studies use critical speed (Ucrit), a laboratory flume measure derived by increasing flow until larvae can no longer maintain their position. Most swimming ability data on fish larvae are Ucrit, usually for larvae nearing the end of PLD. Recognizing that a forced laboratory measure is inappropriate for dispersal, researchers have used decreased Ucrit values, usually by 50%, and have argued that Ucrit is strongly correlated with more relevant swimming measures. Here I examined the suitability of Ucrit versus in situ speed (ISS), wherein speed of larvae is measured by divers following them in the ocean with a flow meter. Considerations of dispersal require inclusion of swimming ontogeny. Swimming speed regressions of speed on size of 10 species in 8 families showed that Ucrit and ISS are not well correlated. The Ucrit:standard length (SL) slope was greater than the ISS:SL slope in 6 species, and did not differ in the other 4 species. No overall metric, e.g. X% of Ucrit = ISS, was appropriate for conversion of Ucrit to ISS. Conversion of Ucrit to ISS is not straightforward. Ucrit measures swimming potential, not what larvae do in the ocean, whereas ISS directly measures larvae swimming in the ocean. Ucrit ontogeny is less variable, but ISS ontogeny is more relevant to dispersal. Ucrit may be useful for other purposes.

Lymphocytopaenia is associated with severe SARS-CoV-2 disease: A Systematic Review and Meta-Analysis of Clinical Data

ABSTRACTBackgroundMost patients infected by SARS-CoV-2 have favourable outcomes, however some develop severe disease which may progress to acute respiratory distress syndrome, multi-organ failure, and death. Markers that could predict patients at risk of poor outcomes would be extremely useful clinically. Evidence has emerged that low lymphocyte count is associated with increased disease severity.MethodsWe performed a systematic review and meta-analysis to assess the association between lymphocyte count and severity of SARS-CoV-2 associated clinical disease.ResultsSeven papers were included in the meta-analysis. These papers included data from 2083 patients, 25% (n=521) with severe SAR-CoV-2 disease and 75% (n=1562) with non-severe SAR-CoV-2 disease. Heterogenicity was seen in the definition of severe disease. Metanalysis produced metamedians of 1×109/L (95% CI 1-1.1) and 0.7×109/L (95% CI 0.63-0.8) lymphocytes for patients with non-severe and severe disease respectively (p-value of p=0.006 Wilcoxon test). Calculation of metamedians from the two papers classifying severe disease according to death alone gave 1.1 1×109/L lymphocytes (95% CI 1.0-1.1) for ‘survivors’ (n=163) and 0.63 1×109/L lymphocytes (95% CI 0.60-0.63) for ‘non-survivors’ (n=253) of SAR-CoV-2 disease.ConclusionsLower lymphocyte counts are significantly associated with more severe disease in patients with SARS-CoV-2 infection. Lymphocytopenia may therefore be useful laboratory measure to allow prognostication of patients presenting with SARS-CoV-2 infection.

Reaction time indices of automatic imitation measure imitative response tendencies

In his review, Ramsey (2018) argues that it is currently unclear what reaction time indices of automatic imitation measure due to lacking research on their validity and domain-specificity. In our commentary, we argue that this conclusion is based on two misconceptions, namely that automatic imitation was designed as a laboratory measure of motor mimicry and that psychometric approaches to validity can readily be applied to experimental settings. We then show that reaction time indices of automatic imitation measure covert imitative response tendencies. Furthermore, while irrelevant for validity, we argue that these indices are associated with some, but not necessarily all, types of overt imitation. Finally, we argue that mapping out the brain networks does not suffice to understand the brain processes underlying imitative control.

SUN PROTECTION FACTOR DETERMINATION STUDIES OF SOME SUNSCREEN FORMULATIONS USED IN COSMETICS FOR THEIR SELECTION

The study involves determination of sun protection factor (SPF) values of some sunscreen formulations for their use in cosmetics. The Sun Protection Factor (SPF) is a very popular instrument in the marketing of sunscreens. Sun protection factor is a laboratory measure of the effectiveness of sunscreen, the higher the SPF, the more protection a sunscreen offers against the ultraviolet radiations causing sunburn. It is often not understood how sunscreens work and where the limitations of the SPF are. A lot of aspects of the SPF are confusing, e.g. the race for higher and higher numbers, the effect on SPF when less sunscreen is applied and if sunscreen should be used at all because they may block the Vitamin D synthesis. The study explains how sunscreens work, how the SPF is determined and where the limitations of the current methods exist. The dynamic view of 'UV radiation applied' and the 'UV dose transmitted' through the sunscreen onto the skin as well as onto a substrate in vitro help in the understanding and are also promising approaches in the in vitro assessment. The study is helpful in selection of some sunscreens formulations used in cosmetics with better safety and high SPF values. Keywords: Sun Protection Factor, SPF, Sunscreens

The Nonlinear Development of Emotion Differentiation: Granular Emotional Experience Is Low in Adolescence

People differ in how specifically they separate affective experiences into different emotion types—a skill called emotion differentiation or emotional granularity. Although increased emotion differentiation has been associated with positive mental health outcomes, little is known about its development. Participants ( N = 143) between the ages of 5 and 25 years completed a laboratory measure of negative emotion differentiation in which they rated how much a series of aversive images made them feel angry, disgusted, sad, scared, and upset. Emotion-differentiation scores were computed using intraclass correlations. Emotion differentiation followed a nonlinear developmental trajectory: It fell from childhood to adolescence and rose from adolescence to adulthood. Mediation analyses suggested that an increased tendency to report feeling emotions one at a time explained elevated emotion differentiation in childhood. Importantly, two other mediators (intensity of emotional experiences and scale use) did not explain this developmental trend. Hence, low emotion differentiation in adolescence may arise because adolescents have little experience conceptualizing co-occurring emotions.

Validating a Standardized Approach to the Taylor Aggression Paradigm

The Taylor Aggression Paradigm (TAP) is a frequently-used laboratory measure of aggression. However, the flexibility inherent in its implementation and analysis can undermine its validity. To test whether the TAP is a valid aggression measure irrespective of this flexibility, we conducted two preregistered studies (Study 1 N = 177, Study 2 N = 167) of a standardized version of the TAP. Across both studies, TAP scores showed agreement with other laboratory aggression measures, were magnified by an experimental provocation manipulation, and were associated with traits typically linked to aggressive behavior. Mixed evidence was found for the external and discriminant validity of the task. Individual responses largely loaded onto a single component, suggesting that the aggregate scoring approach accurately represents the underlying data structure. These results provide preliminary support for the internal validity of this TAP approach and highlight the utility of preregistration in psychometric research.