In this article, I revisit some basic issues concerning structural uncertainty and catastrophic climate change. My target audience here are general economists, so this article could also be viewed as ...a somewhat less technical exposition that supplements my previous work. Using empirical examples, I argue that it is implausible that low-probability, high-negative impact events would not much influence an economic analysis of climate change. I then try to integrate the empirical examples and the theory together into a unified package with a unified message that the possibility of catastrophic climate change needs to be taken seriously.
Flexoelectricity refers to electric polarization generated by heterogeneous mechanical strains, namely strain gradients, in materials of arbitrary crystal symmetries. Despite more than 50 years of ...work on this effect, an accurate identification of its coupling strength remains an experimental challenge for most materials, which impedes its wide recognition. Here, we show the presence of flexoelectricity in the recently discovered polar vortices in PbTiO3/SrTiO3 superlattices based on a combination of machine-learning analysis of the atomic-scale electron microscopy imaging data and phenomenological phase-field modeling. By scrutinizing the influence of flexocoupling on the global vortex structure, we match theory and experiment using computer vision methodologies to determine the flexoelectric coefficients for PbTiO3 and SrTiO3. Our findings highlight the inherent, nontrivial role of flexoelectricity in the generation of emergent complex polarization morphologies and demonstrate a viable approach to delineating this effect, conducive to the deeper exploration of both topics.
Brush block copolymers are a class of comb polymers that feature polymeric side chains densely grafted to a linear backbone. These polymers display interesting properties due to their dense ...functionality, low entanglement, and ability to rapidly self‐assemble to highly ordered nanostructures. The ability to prepare brush polymers with precise structures has been enabled by advancements in controlled polymerization techniques. This Feature Article highlights the development of brush block copolymers as photonic crystals that can reflect visible to near‐infrared wavelengths of light. Fabrication of these materials relies on polymer self‐assembly processes to achieve nanoscale ordering, which allows for the rapid preparation of photonic crystals from common organic chemical feedstocks. The characteristic physical properties of brush block copolymers are discussed, along with methods for their preparation. Strategies to induce self‐assembly at ambient temperatures and the use of blending techniques to tune photonic properties are emphasized.
Brush block copolymers have emerged as promising components in the bottom‐up synthesis of photonic crystals from common organic chemical feedstocks. This polymer architecture permits fabrication of photonic crystal films under ambient conditions driven by self‐assembly. Photonic properties can be controlled by the backbone length of the brush block copolymer or by utilizing blending techniques.
Hydrosilation reactions represent an important class of chemical transformations and there has been considerable recent interest in expanding the scope of these reactions by developing new catalysts. ...A major theme to emerge from these investigations is the development of catalysts with electrophilic character that transfer electrophilicity to silicon by Si‐H activation. This type of mechanism has been proposed for catalysts ranging from Group 4 transition metals to Group 15 main group species. Additionally, other electrophilic silicon species, such as silylene complexes and η3‐H2SiRR′ complexes, have been identified as intermediates in hydrosilation reactions. In this Review, different types of catalysts are compared to highlight the range of hydrosilation mechanisms that feature electrophilic silicon centers. The importance of these catalysts to the development of new hydrosilation reactions is also discussed.
On active duty: Catalysts based on elements from Groups 4–15 and that operate through electrophilic silane activation pathways are currently intensively investigated for hydrosilylations. This Review surveys these catalysts and describes several related mechanisms for electrophilic Si‐H activation (σ‐H‐Si coordination, M(H)2=SiRR′ formation, η3‐H2SiRR′ binding).
The current lack of an accurate, cost-effective and non-invasive test that would allow for screening and diagnosis of gynaecological carcinomas, such as endometrial and ovarian cancer, signals the ...necessity for alternative approaches. The potential of spectroscopic techniques in disease investigation and diagnosis has been previously demonstrated. Here, we used attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to analyse urine samples from women with endometrial (n = 10) and ovarian cancer (n = 10), as well as from healthy individuals (n = 10). After applying multivariate analysis and classification algorithms, biomarkers of disease were pointed out and high levels of accuracy were achieved for both endometrial (95% sensitivity, 100% specificity; accuracy: 95%) and ovarian cancer (100% sensitivity, 96.3% specificity; accuracy 100%). The efficacy of this approach, in combination with the non-invasive method for urine collection, suggest a potential diagnostic tool for endometrial and ovarian cancers.
The assessment of sexual arousal in men and women informs theoretical studies of human sexuality and provides a method to assess and evaluate the treatment of sexual dysfunctions and paraphilias. ...Understanding measures of arousal is, therefore, paramount to further theoretical and practical advances in the study of human sexuality. In this meta-analysis, we review research to quantify the extent of agreement between self-reported and genital measures of sexual arousal, to determine if there is a gender difference in this agreement, and to identify theoretical and methodological moderators of subjective-genital agreement. We identified 132 peer- or academically-reviewed laboratory studies published between 1969 and 2007 reporting a correlation between self-reported and genital measures of sexual arousal, with total sample sizes of 2,505 women and 1,918 men. There was a statistically significant gender difference in the agreement between self-reported and genital measures, with men (
r
= .66) showing a greater degree of agreement than women (
r
= .26). Two methodological moderators of the gender difference in subjective-genital agreement were identified: stimulus variability and timing of the assessment of self-reported sexual arousal. The results have implications for assessment of sexual arousal, the nature of gender differences in sexual arousal, and models of sexual response.
Objective To compare the duration of parenteral nutrition, growth, and morbidity in extremely premature infants fed exclusive diets of either bovine milk–based preterm formula (BOV) or donor human ...milk and human milk-based human milk fortifier (HUM), in a randomized trial of formula vs human milk. Study design Multicenter randomized controlled trial. The authors studied extremely preterm infants whose mothers did not provide their milk. Infants were fed either BOV or an exclusive human milk diet of pasteurized donor human milk and HUM. The major outcome was duration of parenteral nutrition. Secondary outcomes were growth, respiratory support, and necrotizing enterocolitis (NEC). Results Birth weight (983 vs 996 g) and gestational age (27.5 vs 27.7 wk), in BOV and HUM, respectively, were similar. There was a significant difference in median parenteral nutrition days: 36 vs 27, in BOV vs HUM, respectively ( P = .04). The incidence of NEC in BOV was 21% (5 cases) vs 3% in HUM (1 case), P = .08; surgical NEC was significantly higher in BOV (4 cases) than HUM (0 cases), P = .04. Conclusions In extremely preterm infants given exclusive diets of preterm formula vs human milk, there was a significantly greater duration of parenteral nutrition and higher rate of surgical NEC in infants receiving preterm formula. This trial supports the use of an exclusive human milk diet to nourish extremely preterm infants in the neonatal intensive care unit.
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