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In the first chapter, I estimate an elasticity of irrigation adoption to its gross returns in rural India. Many approaches to estimating this elasticity fail when agents select into adopting irrigation on heterogeneous gross returns and costs. I develop a novel approach to correct for selection using two instrumental variable estimators that can be implemented with aggregate data on gross revenue and adoption of irrigation. I use climate and soil characteristics as an instrument for gross returns to irrigation, and hydrogeology as an instrument for irrigation to correct for selection. I estimate that a 1% increase in the gross returns to irrigation causes a 0.7% increase in adoption of irrigation. I use this elasticity to infer changes in profits from changes in adoption of irrigation caused by shocks to its profitability, and to conduct counterfactuals. First, groundwater depletion from 2000-2010 in northwestern India permanently reduced economic surplus by 1.2% of gross agricultural revenue. Second, I evaluate a policy that optimally reduces relative subsidies for groundwater irrigation in districts with large negative pumping externalities, while holding total subsidies fixed. Under the policy, depletion caused by subsidies decreases by 16%, but farmer surplus increases by only 0.07% of gross agricultural revenue.In the second chapter, co-authored with Maria Jones, Florence Kondylis, and Jeremy Magruder, we examine the returns to newly-constructed hillside irrigation schemes in Rwanda using a very granular spatial regression discontinuity design. We find that irrigation enables dry season horticultural production which is associated with large increases in labor and input usage and boosts on-farm yields and cash profits by 70%. At the same time, irrigation use remains limited after 4 years. We leverage the spatial discontinuity in access to irrigation to develop a test for separation failures based on farmer behavior on other plots and conclude that separation failures restrain technology adoption. Unlike existing separation tests, our test allows us to distinguish the role of labor constraints from credit and insurance constraints; we find robust evidence that labor constraints limit adoption.In the third chapter, I develop a new approach to quantify the welfare gains from risky technologies for intertemporal substitution, ranging from agricultural technologies to financial products. Traditionally, these welfare gains are measured either by the technology’s effect on a welfare proxy or by estimating a structural model. Using a welfare proxy may be suboptimal due to noise in measurement and the challenge of converting estimated effects into a money metric, while structural approaches may require strong functional form assumptions and depend on unexpected moments of the data. In contrast, despite some drawbacks, Marshallian consumer surplus is frequently used as a metric for the welfare gains from access to a new product in a static setting, and with sufficient variation in prices may be relatively easy to precisely estimate. I show that under a broad class of models of dynamic optimization which nest Deaton (1991), Marshallian consumer surplus is a reasonable welfare metric for access to an intertemporal substitution technology. I demonstrate how to calculate it, and apply the approach to three experiments which randomly varied either interest rates or prices: I compare the consumer surplus from grants of index insurance in Ghana to their actuarially fair value, I calculate the surplus to households from access to a leading MFI in Mexico, and I bound the foregone consumer surplus due to inattention to the Savers’ Credit among households in the United States. In all cases, the calculation is straightforward, transparent, and can be represented graphically as a “welfare triangle”.

Issue addressed: Running since 1999, the Sanitarium Weet-Bix Kids TRYathlon (SWKT) is the world's largest triathlon series for children and adolescents up to 16 years. This report seeks to describe participants of the TRYathlon and their perceptions of the event. Methods: An online survey was made available to Australian parents/guardians of participants enrolled in the 2020 SWKT. Organisational data was also employed to describe the reach of the SWKT since its inception. Results: Parents/guardians (n = 568) reported that the average child age was 9.12 (SD = 1.95, range = 6-16) and 58.6% were male. Parents/guardians identified 12 children as Aboriginal and/or Torres Strait Islander (2.0%) and 87 (14.6%) spoke a language other than English. The majority of parents/guardians rated their child's physical activity (PA) competencies as pretty good, or really good, for cycling (87.5%), swimming (80.9%) and running (79.5%). Most parents (66.0%) stated that their child was glowing with pride after completing the event, enjoyed or really enjoyed the event (98.8%), and thought their child would maintain their PA levels following the event (72.9%). Conclusions: The SWKT series has demonstrated longevity and an ability to reach a large number of participants, providing opportunities to build health promotion awareness. Importantly the event instils a sense of confidence and pride related to PA competency in its participants; however, its long-term effectiveness requires further exploration. So what?: Mass participation events such as SWKT could be incorporated into larger health promotion strategies to encourage childhood PA and foster healthy physical and psychosocial development.

BackgroundCoeliac disease (CD) is common. Response to a gluten-free diet is assessed through serial measurement of tissue transglutaminase (TTG) antibody titre. However, the relationship of TTG titres to symptoms and the speed of normalisation is poorly understood.MethodsPatients seen in 2020, and under follow-up in the Southampton CD clinic, had blood results, growth measures and symptom data collated. Time to normalisation, predictors of normalisation and relationship of TTG to growth/symptoms were assessed.Results57 patients were included. All had TTG results from the time of diagnosis and follow-up. All families reported dietary compliance.Median TTG at diagnosis was 100 μ/L (range 0.3–4360), 94.7% of the patients had symptoms compatible with CD. At 6–12 months after diagnosis, the median TTG was 3.8 μ/mL (range 0.3–133). In terms of response, 29 of the 57 patients (50.9%) had a TTG below 4 μ/mL (upper normal limit). A further 25 patients (43.9%) had a TTG12 months.TTG at diagnosis was correlated with TTG at 6–12 months, β=0.542, p=0.000016. Patients with TTG10 times normal (85% vs 32.4%, p=0.0015). TTG titres did not correlate with growth measures (Z-scores) at diagnosis or at follow-up.ConclusionsNormalisation of TTG levels occurs within 6–12 months for around half of patients. Higher TTG levels at diagnosis take longer to normalise. The role of compliance is unclear.

Regular physical activity supports children's physical and psychological health and wellbeing, and provides opportunities to build social and emotional skills such as resilience, confidence, and self-efficacy. Research has demonstrated that mass participant sporting events can serve as important social and environmental correlates of physical activity. This study sought to explore parents and children's perceived motivations and perspectives of participation in the Australian Sanitarium Weet-Bix Kids TRYathlon (a non-competitive triathlon series), on children's health and well-being. An exploratory qualitative design utilizing seven focus groups were conducted with 27 family units including 31 parents and 61 children (age 7-15 years old). Data were recorded, professionally transcribed and then analyzed using thematic analysis. Three overarching themes were identified, including (1) motivations for event and physical activity participation, revealing social interaction, peer support and friendly competition as motivators for participation as well as parents' interest in supporting the development of healthy habits; (2) Perceived physical activity, fitness, and developmental benefits, detailing changes to the types of physical activity children performed as well as opportunities for children to develop physical skills and competencies; and (3) Perceived psychosocial benefits of participation, highlighting opportunities for children to develop and demonstrate independence and autonomy through event participation. Notably, parents and children identified benefits beyond immediate participation including increased family engagement and social support. Mass participant events hold the potential to elicit a range of benefits for children and their families; however, further efforts may be needed to engage less active or disengaged families.The physical and psychological benefits of being physically active during childhood are well established. However, most Australian children do not exercise at sufficient levels to receive the full extent of these health benefits. Research has demonstrated that mass participant sporting events can create supportive environments to engage in physical activity and sport whilst promoting mental, social and emotional well-being, but their impact on youth is unknown. Therefore, this study explored parents and children’s perceived motivations and perspectives of participation in a mass participant sporting event, the Australian Sanitarium Weet-Bix Kids TRYathlon, on children’s health and well-being. Our research indicated a range of motivators for engaging in the event, including social interaction, peer support, friendly competition and parents’ interest in supporting healthy habits. The study also highlighted numerous perceived physical and psychosocial benefits of participation, such as increased physical activity pre and post-event, improved physical competency, enhanced confidence and increased family engagement and social support. Nonetheless, we believe further efforts may be needed to engage less active or disengaged families in the Australian Sanitarium Weet-Bix Kids TRYathlon and promote behaviour change.

Hearing loss caused by the death of cochlear hair cells (HCs) might be restored through regeneration from supporting cells (SCs) via dedifferentiation and proliferation, as observed in birds. We recently found that in mice, activation of ERBB2 in SCs promoted the differentiation of hair cell-like cells. Here we analyze transcriptomes of neonatal mouse cochlear SCs with activated ERBB2 using single-cell RNA sequencing. ERBB2 induction in vivo generated a new population of cells expressing de novo SIBLING (small integrin-binding ligand n-linked glycoproteins) proteins and their regulators, particularly Secreted Phosphoprotein 1 (SPP1). In other systems, SIBLINGs promote cell survival, proliferation, and differentiation. ERBB2 signaling induced after noise exposure in young adult mice also up-regulated the SPP1 receptor CD44, and drove formation of stem-like cell aggregates in the organ of Corti. Our results suggest that ectopic activation of ERBB2 signaling in cochlear supporting cells alters the microenvironment, promoting proliferation and cell rearrangements.

Previous work has suggested the ability of 4-hydroxybenzoic acid (4HBA) to bind to β -casein following ultra high temperature-like processing (UHT) in model aqueous systems. The present work confirmed directly, using MALDI-TOF-MS, the presence of covalently bound 4HBA following UHT-like treatment. In subsequent molecular dynamics simulations, the 3D structure of the β -casein molecule was modified so that the meta-C of 4HBA ring and the side chain amino group of lys32 were linked covalently. Such simulations further indicated that the covalent addition of the phenolic compound had impacted the protein density and solvent accessibility. Hydrogen bond analysis between lys32 and the remainder of the protein structure revealed that the covalent complexation supported the formation of additional hydrogen bonds. These increased from potentially 9, in the single protein molecule, to 51 in the complex with 4HBA. However, the persistence of hydrogen bonds was reduced, leading overall to decreased stability and increased protein flexibility.