Recognition and attractiveness as a function of sex and race

The present experiment replicated and refined.tests of. recognition memory for the human face. Three subject groups were used: White American females, White American males and Black African Malawian males. In part one, eighty monochromatic slides of Black and White American college seniors of both sexes were shown as (original) stimuli and then shown again with eighty new slides in a paired comparison task. An analysis of variance performed on the recognition scores revealed the following results: (a) A main effect for groups of slides with American females generating significantly fewer errors than the African males; (b) A main effect for race of slide with White slides generating fewer errors than Black slides for the American subjects; (c) A group by sex interaction with females recognizing female slides better than Black or White males, and male slides better than the Malawians; and (d) A group by race interaction with Whites recognizing White slides better than Black slides, and White males generating significantly fewer errors in recognizing White faces than did Malawian males. In part two, the same subjects rated 144 slides for attractiveness, on a scale of one to five. Spearman\u27s rank, order correlations were made between all pairs of groups on the attractiveness judgments for each sex and race of slide. Significant agreement.of attractiveness judgments was found for all sex/race categories by\u27American males and females, African males and American males judging Black male and female slides, and African males and American females judging Black male slides, Further, Spearman’s correlations between attractiveness judgments and recognizability of slide yielded two significant resultsi a positive correlation between recognizability and attractiveness for White males looking at White male slides, and a negative correlation for White females looking at Black female slides. An additional observation was that all White Americans overestimated the percentage of Blacks presently attending the University of Nebraska at Omaha

Changes in geometrical aspects of a simple model of cilia synchronization control the dynamical state, a possible mechanism for switching of swimming gaits in microswimmers.

Active oscillators, with purely hydrodynamic coupling, are useful simple models to understand various aspects of motile cilia synchronization. Motile cilia are used by microorganisms to swim and to control the flow fields in their surroundings; the patterns observed in cilia carpets can be remarkably complex, and can be changed over time by the organism. It is often not known to what extent the coupling between cilia is due to just hydrodynamic forces, and neither is it known if it is biological or physical triggers that can change the dynamical collective state. Here we treat this question from a very simplified point of view. We describe three possible mechanisms that enable a switch in the dynamical state, in a simple scenario of a chain of oscillators. We find that shape-change provides the most consistent strategy to control collective dynamics, but also imposing small changes in frequency produces some unique stable states. Demonstrating these effects in the abstract minimal model proves that these could be possible explanations for gait switching seen in ciliated micro organisms like Paramecium and others. Microorganisms with many cilia could in principle be taking advantage of hydrodynamic coupling, to switch their swimming gait through either a shape change that manifests in decreased coupling between groups of cilia, or alterations to the beat style of a small subset of the cilia

A Nutrigenomic Perspective to Search for Gene Variants That Influence Carcass Traits of Feedlot Cattle

Vitamin A (VA) has a nutrigenomic effect on intramuscular fat. Discovering variants in genes involved in fat deposition that are also affected by vitamin A could allow feedlots to precision feed to optimize carcass traits. A single nucleotide polymorphism (SNP) in alcohol dehydrogenase 1C (ADH1C) has previously shown promise for this approach but has yet to be effective at a commercial level; therefore we hypothesized a variant in another gene or its interaction with ADH1Cc.-64T>C might be the solution. Genes previously shown to be affected by retinoic acid, a metabolite of vitamin A: aminopeptidase (ANPEP), clusterin (CLU), adipose differentiation-related protein (ADFP), glutathione peroxidase (GPX3), secreted protein, acidic, cysteine-rich (SPARC), and insulin growth factor binding protein 6 (IGFBP6) were sequenced and screened for variants. The ANPEPc.410G>A SNP was selected for genotyping in a population of mixed breed steers (n=988). This population was fed vitamin A at 100% (100VA) or 50% (50VA the NRC recommended level (2200 IU/kg dry matter). No interaction was found with ADH1Cc.-64T>C however, ANPEPc.410G>A affected carcass yield (PA affected rib-eye area (PA is the fourth variant in a haplotype containing twelve SNPs that are in linkage disequilibrium in exon 1 and intron 1. This was confirmed by sequencing cattle of various breeds from different populations. The three haplotypes could affect gene expression by altering transcription or translation efficiency. Investigation of the functional effects of these variants needs to be completed in order to understand how it alters traits related to feedlot cattle performance

Changes in geometrical aspects of a simple model of cilia synchronization control the dynamical state, a possible mechanism for switching of swimming gaits in microswimmers.

Active oscillators, with purely hydrodynamic coupling, are useful simple models to understand various aspects of motile cilia synchronization. Motile cilia are used by microorganisms to swim and to control the flow fields in their surroundings; the patterns observed in cilia carpets can be remarkably complex, and can be changed over time by the organism. It is often not known to what extent the coupling between cilia is due to just hydrodynamic forces, and neither is it known if it is biological or physical triggers that can change the dynamical collective state. Here we treat this question from a very simplified point of view. We describe three possible mechanisms that enable a switch in the dynamical state, in a simple scenario of a chain of oscillators. We find that shape-change provides the most consistent strategy to control collective dynamics, but also imposing small changes in frequency produces some unique stable states. Demonstrating these effects in the abstract minimal model proves that these could be possible explanations for gait switching seen in ciliated micro organisms like Paramecium and others. Microorganisms with many cilia could in principle be taking advantage of hydrodynamic coupling, to switch their swimming gait through either a shape change that manifests in decreased coupling between groups of cilia, or alterations to the beat style of a small subset of the cilia

Controlling the collective dynamics in systems of active oscillators through geometry and hydrodynamic entrainment

Synchronisation is broadly defined as the coordinated action of two or more individual elements that exhibit some time periodic behaviour. It is widely observed across different systems, where it is often a help or hindrance. Here the focus is on synchronisation facilitated by hydrodynamic coupling, with the viscous forces dominating. This style of coupling is spatially dependent, and so the steady state dynamics of the oscillators can be controlled using their positions. I study 'rower' oscillators, a highly simplified model for motile cilia that approximates each cilium by a rigid sphere that is driven by a geometrically updated force. The simplicity of the model lends itself to generic results that could be observed in many systems with hydrodynamic coupling. This thesis is broken into two main parts. The first focuses on developing an analytical framework to further understand the synchronisation between two oscillators coupled through hydrodynamic forces. To achieve this a phase reduction is applied to the geometric oscillators. To apply a phase reduction first the transformation the natural phase is determined; the natural phase is characterised by constant phase velocity and involves a moving reference frame. Following the transformation, the interaction is subjected to an averaging process. The result is a continuous interaction function characterised by the phase difference of two oscillators. This dramatically simplifies the system and allows standard dynamical system techniques to be applied. The new interaction is verified through a comparison of relaxation time, before it is used to predict the steady state through the examination of fixed points. This framework is then used to demonstrate the ability to entrain a rower is not sensitive to changes in the characteristics of the rower motion, while the synchronisation between rowers is susceptible. Estimates of the relative synchronisation strength vis-a-vis the entrainment were calculated for two single cells flagellates and two types ciliated epithelium. Early results indicate different susceptibility between the species, and conclusions regarding interactions between oscillators should be drawn carefully from their behaviour under external flow. Applying phase reduction to active, `rower' oscillators reduces their dynamics to an interaction function depending exclusively on the phase difference. This ties them into the larger context of Kuramoto oscillators, one of the simplest and most widely studied types of phase oscillators. The phase reduction also allows fixed point analysis and other standard nonlinear techniques to be applied. Facilitating direct comparison between different oscillator motions and the prediction of the steady state dynamics. The second part of this thesis departs from the earlier framework and instead phenomenologically explores how to control subset formation in rower arrays. This is achieved either through the array configuration or through characteristics of the oscillators. Often the arrays in this section are too large to be easily understood through the phase reduction approach, leading to investigations carried out predominantly by simulation. The hydrodynamic nature of the coupling allows the strength and coupling range to be altered using the geometry of the array. This can then influence the preferred geometry of any sub-populations that form in the array. Inspiration for specific controlling geometries is drawn from biological systems and abstract work focused on generic oscillators. Irregularities in the oscillators are also introduced in a regular way as an alternative control option that could be relevant for biological organisms. The geometric controls investigated showed the most consistent control of subset formation, but previously transient states were stabilised with each control mechanism. This section demonstrates the rich and complex collection of behaviours that can occur in systems with hydrodynamic coupling. This has applications in actualising states that are usually investigated more abstractly, and in biological systems where hydrodynamic forces are suspected to play a defining role.Winton Programme for the Physics of Sustainability Cambridge Trus

Entrainment of mammalian motile cilia in the brain with hydrodynamic forces.

Motile cilia are widespread across the animal and plant kingdoms, displaying complex collective dynamics central to their physiology. Their coordination mechanism is not generally understood, with previous work mainly focusing on algae and protists. We study here the entrainment of cilia beat in multiciliated cells from brain ventricles. The response to controlled oscillatory external flows shows that flows at a similar frequency to the actively beating cilia can entrain cilia oscillations. We find that the hydrodynamic forces required for this entrainment strongly depend on the number of cilia per cell. Cells with few cilia (up to five) can be entrained at flows comparable to cilia-driven flows, in contrast with what was recently observed in Chlamydomonas Experimental trends are quantitatively described by a model that accounts for hydrodynamic screening of packed cilia and the chemomechanical energy efficiency of the flagellar beat. Simulations of a minimal model of cilia interacting hydrodynamically show the same trends observed in cilia

The Global Lake Ecological Observatory Network (GLEON): the evolution of grassroots network science

Nine years later, with over 380 members from 40 countries, and 50 publications to its credit, GLEON is growing at a rapid pace and pushing the boundaries of the practice of network science. GLEON is really three networks: a network of lakes, data, and peopl

Sex-Specific Cardiovascular Risks of Cancer and Its Therapies

In both cardiovascular disease and cancer, there are established sex-based differences in prevalence and outcomes. Males and females may also differ in terms of risk of cardiotoxicity following cancer therapy, including heart failure, cardiomyopathy, atherosclerosis, thromboembolism, arrhythmias, and myocarditis. Here, we describe sex-based differences in the epidemiology and pathophysiology of cardiotoxicity associated with anthracyclines, hematopoietic stem cell transplant (HCT), hormone therapy and immune therapy. Relative to males, the risk of anthracycline-induced cardiotoxicity is higher in prepubertal females, lower in premenopausal females, and similar in postmenopausal females. For autologous hematopoietic cell transplant, several studies suggest an increased risk of late heart failure in female lymphoma patients, but sex-based differences have not been shown for allogeneic hematopoietic cell transplant. Hormone therapies including GnRH (gonadotropin-releasing hormone) modulators, androgen receptor antagonists, selective estrogen receptor modulators, and aromatase inhibitors are associated with cardiotoxicity, including arrhythmia and venous thromboembolism. However, sex-based differences have not yet been elucidated. Evaluation of sex differences in cardiotoxicity related to immune therapy is limited, in part, due to low participation of females in relevant clinical trials. However, some studies suggest that females are at increased risk of immune checkpoint inhibitor myocarditis, although this has not been consistently demonstrated. For each of the aforementioned cancer therapies, we consider sex-based differences according to cardiotoxicity management. We identify knowledge gaps to guide future mechanistic and prospective clinical studies. Furthering our understanding of sex-based differences in cancer therapy cardiotoxicity can advance the development of targeted preventive and therapeutic cardioprotective strategies