Twenty years of stereotype threat research: A review of psychological mediators

This systematic literature review appraises critically the mediating variables of stereotype threat. A bibliographic search was conducted across electronic databases between 1995 and 2015. The search identified 45 experiments from 38 articles and 17 unique proposed mediators that were categorized into affective/subjective (n = 6), cognitive (n = 7) and motivational mechanisms (n = 4). Empirical support was accrued for mediators such as anxiety, negative thinking, and mind-wandering, which are suggested to co-opt working memory resources under stereotype threat. Other research points to the assertion that stereotype threatened individuals may be motivated to disconfirm negative stereotypes, which can have a paradoxical effect of hampering performance. However, stereotype threat appears to affect diverse social groups in different ways, with no one mediator providing unequivocal empirical support. Underpinned by the multi-threat framework, the discussion postulates that different forms of stereotype threat may be mediated by distinct mechanisms

Shaping and Structuring Supramolecular Gels

Supramolecular gels assemble via non-covalent interactions between low-molecular-weight gelators (LMWGs). The gels form a solid-like nanoscale network spanning a liquid-like continuous phase, translating molecular-scale information into materials performance. However, gels based on LMWGs are often difficult to manipulate, easily destroyed and have poor rheological performance. The recurring image of newly-discovered supramolecular gels is that of an inverted vial showing that the gel can support its own weight against gravity. Such images reflect the limitation that these gels simply fill the vessel in which they are made, with limited ability to be shaped. This property prevents supramolecular gels from having the same impact as polymer gels, despite greater synthetic tunability, reversibility and bio/environmental compatibility. In this Review, we evaluate strategies for imposing different shapes onto supramolecular gels and for patterning structures within them. We review fabrication methods including moulding, self-healing, 3D printing, photopatterning, diffusion and surface-mediated patterning. We discuss gelator chemistries amenable to each method, highlighting how a multi-component approach can aid shaping and structuring. Supramolecular gels with defined shapes, or patterned structures with precisely-controlled compositions, have the potential to intervene in applications such as tissue engineering and nanoscale electronics, as well as opening-up new technologies

Carbon and nitrogen stable isotope signals for an entire alpine flora, based on herbarium samples

Stable carbon and nitrogen isotopes provide time-integrated signals of plant carbon and nitrogen relations. We assessed an entire alpine flora in the Swiss Alps at ca. 2400 m elevation, using year 2007 herbarium samples of 245 species, 141 genera and 42 families to explore functional trait diversity. Despite overall similar macro-environmental conditions (moisture, soils, elevation), signal variation covered the full spectrum known for C3 plants. Variation among means for plant families for both δ13C and δ15N was smaller than variation among species within families. Species identity was of far greater importance than family affiliation. Similarly, tissue nitrogen and carbon concentrations varied in a rather species-specific manner, not permitting any a priori plant functional group definition based on such traits. The study also yielded tissue-type specificity of isotope signals. The elevation signal in δ13C (known to be less negative at high elevation) was much less pronounced than observed previously in con-generic comparisons. Thus, elevational δ13C trends are hard to distinguish from species effects in mixed populations over narrow ranges of elevation. δ15N data offer more space for ecological interpretation and show family specificity of signals in few cases. Cyperaceae, the most prominent family in this region, show no discrimination against 15N (like Fabaceae) and must have access to N sources different from most other families. This deserves experimental clarification, given the significance of Cyperaceae in cold environments. Overall, our study evidenced very high functional diversity among alpine plant species, as captured by these isotope signals