cept of biofortification by regional bodies and governments, which in turn built within country ownership and the willingness of donors to invest. The SPHI united diverse organizations under a common vision with a simple metric--- the number of households reached with improved varieties of sweetpotato. Since 2009, 6.2 million households were reached by July 2019 in 15 SSA countries. Much more remains to be done. Advocacy efforts led to the integration of nutritious foods into many national and regional policies, setting the stage for further investment. © 2019 The Authors.Development is a multi-faceted process; achieving development goals thus requires a multi-sectoral approach. For over two decades, our research group of economists and nutritionists has designed and implemented randomized trials to assess the effectiveness of multisectoral programs in improving nutrition, food security, and other measures of well-being, largely at the request of developing country governments, development partners, and non-governmental organizations. Our approach addresses three perceived pitfalls of RCTs the "black box" nature of RCTs, limited external validity, and challenges in translation of results to impacts at scale. We address these concerns by identifying and assessing programmatic pathways to impact with quantitative and qualitative methods; studying similar programs implemented by different organizations across various settings; and working closely with implementing partners in the design, research, and dissemination processes to inform adaptation and scale-up of programs and policies. © 2019 The Authors.The unique properties of the quantum Hall effect allow one to revisit traditional measurement circuits with a new flavour. In this paper we present the first realization of a quantum Hall Kelvin bridge for the calibration of standard resistors directly against the quantum Hall resistance. The bridge design is particularly simple and requires a minimal number of instruments. The implementation here proposed is based on the bridge-on-a-chip, an integrated circuit composed of three graphene quantum Hall elements and superconducting wiring. The accuracy achieved in the calibration of a 12 906Ω standard resistor is of a few parts in 108, at present mainly limited by the prototype device and the interferences in the current implementation, with the potential to achieve few parts in 109, which is the level of the systematic uncertainty of the quantum Hall Kelvin bridge itself.Empathizing with others is widely presumed to increase our understanding of their emotions. Little is known, however, about which empathic process actually help people recognize others' feelings more accurately. Here, we probed the relationship between emotion recognition and two empathic processes spontaneously felt similarity (having had a similar experience) and deliberate perspective taking (focus on the other vs. oneself). We report four studies in which participants (total N = 803) watched videos of targets sharing genuine negative emotional experiences. Participants' multi-scalar ratings of the targets' emotions were compared with the targets' own emotion ratings. In Study 1 we found that having had a similar experience to what the target was sharing was associated with lower recognition of the target's emotions. Study 2 replicated the same pattern and in addition showed that making participants' own imagined reaction to the described event salient resulted in further reduced accuracy. JPH203 Studies 3 and 4 were preregistered replications and extensions of Studies 1 and 2, in which we observed the same outcome using a different stimulus set, indicating the robustness of the finding. Moreover, Study 4 directly investigated the underlying mechanism of the observed effect. Findings showed that perceivers who have had a negative life experience similar to the emotional event described in the video felt greater personal distress after watching the video, which in part explained their reduced accuracy. These results provide the first demonstration that spontaneous empathy, evoked by similarity in negative experiences, may inhibit rather than increase our understanding of others' emotions. © 2019 The Authors.We describe surface wave propagation in soft elastic media at speeds exceeding the bulk shear wave speed. By linking these waves to the elastodynamic Green's function, we derive a simple relationship to quantify the elasticity of a soft medium from the speed of this supershear evanescent wave (SEW). We experimentally probe SEW propagation in tissue-mimicking phantoms, human cornea ex vivo, and skin in vivo using a high-speed optical coherence elastography system. Measurements confirm the predicted relationship between SEW and bulk shear wave speeds, agreeing well with both theoretical and numerical models. These results suggest that SEW measurements may be a robust method to quantify elasticity in soft media, particularly in complex, bounded materials where dispersive Rayleigh-Lamb modes complicate measurements. Copyright © 2019 Author(s).In recent years, phototransistors have considerably expanded their field of application, including for instance heterodyne detection and optical interconnects. Unlike in low-light imaging, some of these applications require fast photodetectors that can operate in relatively high light levels. Since the gain and bandwidth of phototransistors are not constant across different optical powers, the devices that have been optimized for operation in low light level cannot effectively be employed in different technological applications. We present an extensive study of the gain and bandwidth of short-wavelength infrared phototransistors as a function of optical power level for three device architectures that we designed and fabricated. The gain of the photodetectors is found to increase with increasing carrier injection. Based on a Shockley-Read-Hall recombination model, we show that this is due to the saturation of recombination centers in the phototransistor base layer. Eventually, at a higher light level, the gain drops, due to the Kirk effect. As a result of these opposing mechanisms, the gain-bandwidth product is peaked at a given power level, which depends on the device design and material parameters, such as doping and defect density. Guided by this physical understanding, we design and demonstrate a phototransistor which is capable of reaching a high gain-bandwidth product for high-speed applications. The proposed design criteria can be employed in conjunction with the engineering of the device size to achieve a wide tunability of the gain and bandwidth, hence paving the way toward fast photodetectors for applications with different light levels. Copyright © 2019 Author(s).