Biology subjects

Lee, A. J.

Publications and source records attributed to Lee, A. J..

6 recordsLinked to original sources

bioRxiv2018

Facial masculinity is only weakly correlated with handgrip strength in young adult women

ObjectivesAncestrally, strength is likely to have played a critical role in determining the ability to obtain and retain resources and the allocation of social status among humans. Responses to facial cues of strength are therefore thought to play an important role in human social interaction. Although many researchers have proposed that sexually dimorphic facial morphology is reliably correlated with physical strength, evidence for this hypothesis is somewhat mixed. Moreover, to date, only one study has investigated the putative relationship between facial masculinity and physical strength in women. Consequently, we tested for correlations between handgrip strength and objective measures of face-shape masculinity.\n\nMethods531 women took part in the study. We measured each participants handgrip strength (dominant hand). Sexual dimorphism of face shape was objectively measured from each face photograph using two methods: discriminant analysis and vector analysis. These methods use shape components derived from principal component analyses of facial landmarks to measure the probability of the face being classified as male (discriminant analysis method) or to locate the face on a female-male continuum (vector analysis method).\n\nResultsOur analyses revealed that handgrip strength is, at best, only weakly correlated with facial masculinity in women. There was a weak significant association between handgrip strength and one measure of womens facial masculinity. The relationship between handgrip strength and our other measure of womens facial masculinity was not significant.\n\nDiscussionTogether, these results do not support the hypothesis that face-shape masculinity is an important cue of physical strength, at least in women.

animal behavior and cognition↗

bioRxiv2018

Dissecting bacterial resistance and resilience in antibiotic responses

An essential property of microbial communities is the ability to survive a disturbance. Survival can be achieved through resistance, the ability to absorb effects of a disturbance without a significant change, or resilience, the ability to recover after being perturbed by a disturbance. These concepts have long been applied to the analysis of ecological systems, though their interpretations are often subject to debate. Here we show that this framework readily lends itself to the dissection of the bacterial response to antibiotic treatment, where both terms can be unambiguously defined. The ability to tolerate the antibiotic treatment in the short term corresponds to resistance, which primarily depends on traits associated with individual cells. In contrast, the ability to recover after being perturbed by an antibiotic corresponds to resilience, which primarily depends on traits associated with the population. This framework effectively reveals the phenotypic signatures of bacterial pathogens expressing extended spectrum {beta}-lactamases (ESBLs), when treated by a {beta}-lactam antibiotic. Our analysis has implications for optimizing treatment of these pathogens using a combination of a {beta}-lactam and a {beta}-lactamase (Bla) inhibitor. In particular, our results underscore the need to dynamically optimize combination treatments based on the quantitative features of the bacterial response to the antibiotic or the Bla inhibitor.

cell biology↗

bioRxiv2017

Hormonal regulation of women’s prosocial, but not sexual, responses to kinship cues

Mate preferences and mating-related behaviors are hypothesized to change over the menstrual cycle in ways that function to increase reproductive fitness. Results of recent large-scale studies suggest that many of these hormone-linked behavioral changes are less robust than was previously thought. One hypothesis that has not yet been subject to a large-scale test is the proposal that womens preference for associating with male kin is down-regulated during the ovulatory (high-fertility) phase of the menstrual cycle. Consequently, we used a longitudinal design to investigate the relationship between changes in womens steroid hormone levels and their perceptions of faces experimentally manipulated to possess kinship cues. Analyses suggested that women viewed mens faces displaying kinship cues more positively (i.e., more attractive and trustworthy) when estradiol-to-progesterone ratio was high. Since estradiol-to-progesterone ratio is positively associated with conception risk during the menstrual cycle, these results directly contradict the hypothesis that womens preference for associating with male kin is down-regulated during the ovulatory (high-fertility) phase of the menstrual cycle. Data and code are publicly available at https://osf.io/wnhma/.

animal behavior and cognition↗

bioRxiv2017

DAFi: A Directed Recursive Filtering and Clustering Approach to Data-Driven Identification of Cell Populations from Polychromatic Flow Cytometry Data

Computational methods for identification of cell populations from high-dimensional flow cytometry data are changing the paradigm of cytometry bioinformatics. Data clustering is the most common computational approach to unsupervised identification of cell populations from multidimensional cytometry data. We found that combining recursive filtering and clustering with constraints converted from the user manual gating strategy can effectively identify overlapping and rare cell populations from smeared data that would have been difficult to resolve by either a single run of data clustering or manual segregation. We named this new method DAFi: Directed Automated Filtering and Identification of cell populations. Design of DAFi preserves the data-driven characteristics of unsupervised clustering for identifying novel cell-based biomarkers, but also makes the results interpretable to experimental scientists as in supervised classification through mapping and merging the high-dimensional data clusters into the user-defined 2D gating hierarchy. By recursive data filtering before clustering, DAFi can uncover small local clusters which are otherwise difficult to identify due to the statistical interference of the irrelevant major clusters. Quantitative assessment of cell type specific characteristics demonstrates that the population proportions calculated by DAFi, while being highly consistent with those by expert centralized manual gating, have smaller technical variance than those from individual manual gating analysis. Visual examination of the dot plots showed that the boundaries of the DAFi-identified cell populations followed the natural shapes of the data distributions. To further exemplify the utility of DAFi, we show that DAFi can incorporate the FLOCK clustering method to identify novel cell-based biomarkers. Implementation of DAFi supports options including clustering, bisecting, slope-based gating, and reversed filtering to meet various auto-gating needs from different scientific use cases.

bioinformatics↗

bioRxiv2017

Women’s preferences for facial masculinity are not related to their hormonal status

Although widely cited as strong evidence that sexual selection has shaped human facial attractiveness judgments, evidence that preferences for masculine characteristics in mens faces are related to womens hormonal status is equivocal and controversial. Consequently, we conducted the largest ever longitudinal study of the hormonal correlates of womens preferences for facial masculinity (N=584). Analyses showed no compelling evidence that preferences for facial masculinity were related to changes in womens salivary steroid hormone levels. Furthermore, both within-subject and between-subject comparisons showed no evidence that oral contraceptive use decreased masculinity preferences. However, women generally preferred masculinized over feminized versions of mens faces, particularly when assessing mens attractiveness for short-term, rather than long-term, relationships. Our results do not support the hypothesized link between womens preferences for facial masculinity and their hormonal status.

animal behavior and cognition↗

bioRxiv2017

Within-Woman Hormone-Attractiveness Correlations Are Not Simply Byproducts Of Between-Women Hormone-Attractiveness Correlations

Putative associations between sex hormones and attractive physical characteristics in women are central to many theories of human physical attractiveness and mate choice. Although such theories have become very influential, evidence that physically attractive and unattractive women have different hormonal profiles is equivocal. Consequently, we investigated hypothesized relationships between salivary estradiol and progesterone and two aspects of womens physical attractiveness that are commonly assumed to be correlated with levels of these hormones: facial attractiveness (N=249) and waist-to-hip ratio (N=247). Our analyses revealed no evidence that women with more attractive faces or lower (i.e., more attractive) waist-to-hip ratios had higher levels of estradiol or progesterone. These results do not support the influential hypothesis that between-woman differences in physical attractiveness are related to estradiol and/or progesterone.

animal behavior and cognition↗