Bryn Mawr College
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Extreme temperatures during pregnancy and adverse birth outcomes: Evidence from 2009 to 2018 U.S. national birth data
Get PDFWe provide the first estimates of the impacts of prenatal exposure to extreme temperatures on infant health at birth using the latest national birth data from 2009 to 2018 from all U.S. states. We consistently find that an additional day with mean temperature greater than 80°F or less than 10°F increases preterm births and low birthweight. Strikingly, the adverse effects are borne disproportionately by Black and Hispanic mothers, suggesting that the projected increase in extreme temperatures may further exacerbate the existing birth health disparities across different race/ethnicity groups. We also contribute by investigating the impact of deviations from the normal weather pattern, to identify the extreme weather events after accounting for the adaptation response. We find that prenatal exposure to extreme heat two standard deviations above county\u27s historic average induces preterm births and NICU admissions, particularly for mothers whose pregnancies overlap with summer months. These results are timely and policy relevant, considering the recent weather trends with rising temperatures and frequent extreme weather events
Learning the rules of the game: The role of generic you and we in shaping children\u27s interpretations of norms
Get PDFA critical skill of childhood is learning social norms. We examine whether the generic pronouns “you” and “we,” which frame information as applying to people in general rather than to a specific individual, facilitate this process. In one pre-registered experiment conducted online between 2020 and 2021, children 4- to 9-year-old primarily living in the midwestern U.S. (N = 146, 75 girls, 71 boys, Mage = 7.14, SD = 1.69, 82% White) interpreted actions described with generic pronouns (vs. “I”) as normatively correct and selected the speaker who used generic pronouns as the rule-follower, particularly when generic pronouns were presented first. There were no significant effects of age. These results illustrate how generic pronouns influence how children discern unfamiliar norms and form interpersonal judgments
The effect of polymer stiffness on magnetization reversal of magnetorheological elastomers
Get PDFUltrasoft magnetorheological elastomers (MREs) offer convenient real-time magnetic field control of mechanical properties that provides a means to mimic mechanical cues and regulators of cells in vitro. Here, we systematically investigate the effect of polymer stiffness on magnetization reversal of MREs using a combination of magnetometry measurements and computational modeling. Poly-dimethylsiloxane- based MREs with Young’s moduli that range over two orders of magnitude were synthesized using commercial polymers SylgardTM 527, Sylgard 184, and carbonyl iron powder. The magnetic hysteresis loops of the softer MREs exhibit a characteristic pinched loop shape with almost zero remanence and loop widening at intermediate fields that monotonically decreases with increasing polymer stiffness. A simple two-dipole model that incorporates magneto-mechanical coupling not only confirms that micrometer-scale particle motion along the applied magnetic field direction plays a defining role in the magnetic hysteresis of ultrasoft MREs but also reproduces the observed loop shapes and widening trends for MREs with varying polymer stiffnesses
Khovanov Homology & Uniqueness of Surfaces in the 4-ball
Get PDFWe use the functoriality of Khovanov homology to examine the smooth, boundary-preserving isotopy of surfaces embedded in the 4-ball. We exemplify an infinite family of prime knots that bound an arbitrarily-large number of smoothly-distinct slice disks by distinguishing the maps they induce on Khovanov homology. Similar techniques produce an infinite family of knots that each bound a pair of exotic surfaces of arbitrary genus
