Effective interaction between a colloid and a soft interface near criticality

Within mean-field theory we determine the universal scaling function for the effective force acting on a single colloid located near the interface between two coexisting liquid phases of a binary liquid mixture close to its critical consolute point. This is the first study of critical Casimir forces emerging from the confinement of a fluctuating medium by at least one soft interface, instead by rigid walls only as studied previously. For this specific system, our semi-analytical calculation illustrates that knowledge of the colloid-induced, deformed shape of the interface allows one to accurately describe the effective interaction potential between the colloid and the interface. Moreover, our analysis demonstrates that the critical Casimir force involving a deformable interface is accurately described by a universal scaling function, the shape of which differs from that one for rigid walls.Comment: 19 pages, 11 figure

The Deterrent Effect of Capital Punishment

This project will attempt to determine whether or not capital punishment, in the manner which it is currently used here in the United States, does in fact have a significant deterrent effect on the murder rates across the country. My hypothesis is that such a deterrent effect does exist and that, as the likelihood of being executed increases that deterrent effect will become stronger

Children's Gender Stereotypes in STEM Following a One-Shot Growth Mindset Intervention in a Science Museum.

Women are drastically underrepresented in science, technology, engineering, and mathematics (STEM) and this underrepresentation has been linked to gender stereotypes and ability related beliefs. One way to remedy this may be to challenge male bias gender stereotypes around STEM by cultivating equitable beliefs that both female and male can excel in STEM. The present study implemented a growth mindset intervention to promote children's incremental ability beliefs and investigate the relation between the intervention and children's gender stereotypes in an informal science learning site. Participants (n = 143, female n = 77, male n = 66, 5-12-years-old, M age = 8.6, SD = 1.7) were visitors to a science museum who took part in an interactive space science show. Participants who were exposed to a growth mindset intervention, compared to the participants in the control condition, reported significantly less gender stereotyping around STEM by reporting equitably in the stereotype awareness measure. Relatedly, participants in the control condition reported male bias gender stereotype in the stereotype awareness measure. Further, children between 5 and 8-years-old reported greater male bias stereotypes awareness and stereotype flexibility in space science compared to children between 9 and 12-years-old. Lastly, children demonstrated in-group bias in STEM ability. Male participants reported gender bias favoring males' ability in stereotype flexibility and awareness measures, while female participants reported bias toward females' ability in stereotype flexibility and awareness measures. These findings document the importance of a growth mindset intervention in buffering against STEM gender stereotyping amongst children, as well as the significant role a growth mindset intervention can play within an informal science learning site

Toward Better Understanding on How Group A <em>Streptococcus</em> Manipulates Human Fibrinolytic System

Group A Streptococcus pyogenes (GAS) is a human pathogen that commonly causes superficial infections such as pharyngitis, but can also lead to systemic and fatal diseases. GAS infection remains to be a major threat in regions with insufficient medical infrastructures, leading to half a million deaths annually worldwide. The pathogenesis of GAS is mediated by a number of virulence factors, which function to facilitate bacterial colonization, immune evasion, and deep tissue invasion. In this review, we will discuss the mechanism of molecular interaction between the host protein and virulence factors that target the fibrinolytic system, including streptokinase (SK), plasminogen-binding group A streptococcal M-like protein (PAM), and streptococcal inhibitor of complement (SIC). We will discuss our current understanding, through structural studies, on how these proteins manipulate the fibrinolytic system during infection

L’intégration des évaluations de l’apprentissage autorégulé dans les activités d’évaluation dans les professions de la santé : un appel à l’action

How well have healthcare professionals and trainees been prepared for the inevitable demands for new learning that will arise in their future? Given the rapidity with which ‘core healthcare knowledge’ changes, medical educators have a responsibility to audit whether trainees have developed the capacity to effectively self-regulate their learning. Trainees who engage in effective self-regulated learning (SRL) skilfully monitor and control their cognition, motivation, behaviour, and environment to adaptively meet demands for new learning. However, medical curricula rarely assess trainees’ capacity to engage in this strategic process. In this position paper, we argue for a paradigm shift toward assessing SRL more deliberately in undergraduate and postgraduate programs, as well as in associated licensing activities. Specifically, we explore evidence supporting an innovative blend of principles from the science on SRL, and on preparation for future learning (PFL) assessments. We propose recommendations for how program designers, curriculum developers, and assessment leads in undergraduate and postgraduate training programs, and in licensing bodies can work together to develop integrated assessments that measure how and how well trainees engage in SRL. Claims about lifelong learning in health professions education have gone unmatched by responsive curricular changes for far too long. Further neglecting these important competencies represents a disservice to medical trainees and a potential risk to the future patients they will care for.Dans quelle mesure les professionnels de la santé et les étudiants ont-ils été préparés aux exigences inévitables de nouveaux apprentissages qui se présenteront à eux à l’avenir? Étant donné la rapidité avec laquelle les « connaissances de base en matière de soins de santé » évoluent, les enseignants en médecine ont la responsabilité de vérifier si les étudiants ont développé la capacité d’autoréguler adéquatement leurs apprentissages. Ceux qui pratiquent efficacement l’apprentissage autorégulé (AAR) surveillent et contrôlent habilement leur cognition, leur motivation, leur comportement et leur environnement pour s’adapter à la nécessité de nouveaux apprentissages. Cependant, les programmes d’études médicales évaluent rarement la capacité des étudiants à s’engager dans ce processus stratégique. Dans cet exposé de position, nous plaidons en faveur d’un changement de paradigme vers une évaluation plus ciblée de l’AAR dans les formations doctorale et postdoctorale, ainsi que pour les activités d’évaluation. Plus précisément, nous explorons les résultats convaincants de l’emploi d’un mélange innovant de principes issus de la recherche en matière d’AAR et d’évaluations de la préparation à l’apprentissage futur. Nous proposons des recommandations pour une collaboration entre les responsables de la conception de programmes d’études, ceux de l’élaboration du cursus, ceux chargés de l’évaluation dans les programmes d’études prédoctorales et postdoctorales et les organismes responsables de l’octroi d’un titre de compétence en vue de créer des évaluations intégrées qui mesurent la méthode et la qualité de l’AAR chez les étudiants. Les programmes d’études tardent encore à traduire dans la pratique la reconnaissance de l’importance de l’apprentissage tout au long de la vie dans l’éducation médicale. Continuer à négliger ces compétences importantes ne ferait que nuire aux étudiants en médecine et potentiellement à leurs futurs patients

A New Look at an Old Cluster: The Membership, Rotation, and Magnetic Activity of Low-Mass Stars in the 1.3-Gyr-Old Open Cluster NGC 752

The nearby open cluster NGC 752 presents a rare opportunity to study stellar properties at ages >1 Gyr. However, constructing a membership catalog for it is challenging; most surveys have been limited to identifying its giants and dwarf members earlier than mid-K. We supplement past membership catalogs with candidates selected with updated photometric and proper-motion criteria, generating a list of 258 members, a >50% increase over previous catalogs. Using a Bayesian framework to fit MESA Isochrones & Stellar Tracks evolutionary models to literature photometry and the Tycho-Gaia Astrometric Solution data available for 59 cluster members, we infer the age of, and distance to, NGC 752: 1.34$\pm$0.06 Gyr and 438$_{-6}^{+8}$ pc. We also report the results of our optical monitoring of the cluster using the Palomar Transient Factory. We obtain rotation periods for 12 K and M cluster members, the first periods measured for such low-mass stars with a well-constrained age >1 Gyr. We compare these new periods to data from the younger clusters Praesepe and NGC 6811, and to a theoretical model for angular-momentum loss, to examine stellar spin down for low-mass stars over their first 1.3 Gyr. While on average NGC 752 stars are rotating more slowly than their younger counterparts, the difference is not significant. Finally, we use our spectroscopic observations to measure Halpha for cluster stars, finding that members earlier than $\approx$M2 are magnetically inactive, as expected at this age. Forthcoming Gaia data should solidify and extend the membership of NGC 752 to lower masses, thereby increasing its importance for studies of low-mass stars.Comment: Accepted to ApJ. This version 23 pages, 15 figures; on-line version will include 11 more figures as well as light curve data for the 12 rotators we identif

Anisotropic Self-Assembly from Isotropic Colloidal Building Blocks

© 2017 American Chemical Society. Spherical colloidal particles generally self-assemble into hexagonal lattices in two dimensions. However, more complex, non-hexagonal phases have been predicted theoretically for isotropic particles with a soft repulsive shoulder but have not been experimentally realized. We study the phase behavior of microspheres in the presence of poly(N-isopropylacrylamide) (PNiPAm) microgels at the air/water interface. We observe a complex phase diagram, including phases with chain and square arrangements, which exclusively form in the presence of the microgels. Our experimental data suggests that the microgels form a corona around the microspheres and induce a soft repulsive shoulder that governs the self-assembly in this system. The observed structures are fully reproduced by both minimum energy calculations and finite temperature Monte Carlo simulations of hard core-soft shoulder particles with experimentally realistic interaction parameters. Our results demonstrate how complex, anisotropic assembly patterns can be realized from entirely isotropic building blocks by control of the interaction potential

17O NMR spectroscopy as a tool to study hydrogen bonding of cholesterol in lipid bilayers

Cholesterol is a crucial component of biological membranes and can interact with other membrane components through hydrogen bonding. NMR spectroscopy has been used previously to investigate this bonding, however this study represents the first 17O NMR spectroscopy study of isotopically enriched cholesterol. We demonstrate the 17O chemical shift is dependent on hydrogen bonding, providing a novel method for the study of cholesterol in bilayers

Assessing adolescents' critical health literacy: How is trust in government leadership associated with knowledge of COVID-19?

This study explored relations between COVID-19 news source, trust in COVID-19 information source, and COVID-19 health literacy in 194 STEM-oriented adolescents and young adults from the US and the UK. Analyses suggest that adolescents use both traditional news (e.g., TV or newspapers) and social media news to acquire information about COVID-19 and have average levels of COVID-19 health literacy. Hierarchical linear regression analyses suggest that the association between traditional news media and COVID-19 health literacy depends on participants' level of trust in their government leader. For youth in both the US and the UK who used traditional media for information about COVID-19 and who have higher trust in their respective government leader (i.e., former US President Donald Trump and UK Prime Minister Boris Johnson) had lower COVID-19 health literacy. Results highlight how youth are learning about the pandemic and the importance of not only considering their information source, but also their levels of trust in their government leaders