Princeton University

• Princeton, New Jersey, United States
Recent publications
Are there disparities in children’s memory for gender-neutral pronouns compared with gendered pronouns? We explored this question in two preregistered studies with 4- to 10-year-old children (N = 168; 79 boys, 89 girls, 0 gender-diverse). Participants were presented with a memory task. An experimenter read an illustrated story about a target character. Participants were asked to verbally repeat the story to measure spontaneous pronoun use and then to explicitly recall the characters’ pronouns. In Study 1 the story characters had typically feminine or typically masculine appearances (determined by independent raters), whereas in Study 2 the characters had gender-neutral appearances. In both studies, targets were referred to with gendered or gender-neutral pronouns. In both studies, children more accurately recalled gendered pronouns than gender-neutral pronouns. However, on most tasks, children only used “they” if a character had gender-neutral pronouns, and almost never used “they” if a character had gendered pronouns. We also found some evidence suggesting that older children more accurately recall gender-neutral pronouns compared with younger children.
Vote-buying—or the pre-electoral distribution of private goods in exchange for support at the ballot box—is often blamed for the poor economic performance of many developing countries. By pressuring individuals to vote against their own interest, vote-buying may undermine accountability and the implementation of sound development policies. Yet, these effects depend on it leading to electoral outcomes that would not have occurred otherwise. In this paper we use survey data from 17 sub-Saharan African elections between 2000 and 2005 and 20 Latin American elections between 2005 and 2010 to show that, despite its widespread prevalence, vote-buying has a limited electoral impact on average: in only 11 of 37 elections are gifts-for-votes practices correlated with higher turnout; yet, in only very few elections could have these gifts translated into visible electoral advantages for a particular party. This contrasts with common perceptions about the effectiveness of electoral handouts and the quality of the elections in these regions.
Soil macropores are crucial to assess soil stability and control erosion as an essential component of soil structure. The variations in soil macropores with vegetation succession remain largely unclear, and the regulatory mechanism is still poorly understood. Plant fine roots and arbuscular mycorrhizal fungi (AMF) have been supposed to be dominant determinants of soil structure, but their separate effects on soil macropores remain underappreciated, let alone the effects of their interactions. This study used quantified imaging techniques to explore the effects of plant fine roots and AMF on soil macropores along a 55-year vegetation restoration chronosequence on the Loess Plateau. We found that soil macropore properties, such as macroporosity, connectivity, fractal dimension, and tortuosity, were all significantly improved with vegetation succession. Fine root density properties significantly increased, whereas morphological properties decreased along the restoration chronosequence with a shift to a conservative root resource usage strategy. Furthermore, duration of vegetation succession had a positive effect on AMF community structure and mediated the root chemical properties indirectly. Plant fine roots affected macropores directly with the positive effects of root density properties, whereas the morphological properties and chemical properties had negative effects. By comparison, the influence of the AMF community structure (i.e., AMF species composition) on macropore features was indirectly mediated through root chemical properties. Overall, this study investigated how plant fine roots and AMF separately and/or jointly affected soil macropores via direct and indirect mechanisms. Thus, this study may greatly contribute to restoration by assisting vegetation configuration to improve soil structure and enhancing the ecological function of afforestation.
Open-ended interview questions elicit rich information about people’s lives, but in large-scale surveys, social scientists often need to measure complex concepts using only a few close-ended questions. We propose a new method to design a short survey measure for such cases by combining mixed-methods data collection and machine learning. We identify the best survey questions based on how well they predict a benchmark measure of the concept derived from qualitative interviews. We apply the method to create a survey module and index for women’s agency. We measure agency for 209 married women in Haryana, India, first, through a semi-structured interview and, second, through a large set of close-ended questions. We use qualitative coding methods to score each woman’s agency based on the interview, which we use as a benchmark measure of agency. To determine the close-ended questions most predictive of the benchmark, we apply statistical algorithms that build on LASSO and random forest but constrain how many variables are selected for the model (five in our case). The resulting five-question index is as strongly correlated with the coded qualitative interview as is an index that uses all of the candidate questions. This approach of selecting survey questions based on their statistical correspondence to coded qualitative interviews could be used to design short survey modules for many other latent constructs.
The Ramsey number r(H) of a graph H is the minimum integer n such that any two-coloring of the edges of the complete graph Kn contains a monochromatic copy of H. While this definition only asks for a single monochromatic copy of H, it is often the case that every two-edge-coloring of the complete graph on r(H) vertices contains many monochromatic copies of H. The minimum number of such copies over all two-colorings of Kr(H) will be referred to as the threshold Ramsey multiplicity of H. Addressing a problem of Harary and Prins, who were the first to systematically study this quantity, we show that there is a positive constant c such that the threshold Ramsey multiplicity of a path or an even cycle on k vertices is at least (ck)k. This bound is tight up to the constant c. We prove a similar result for odd cycles in a companion paper.
Curiosity plays a key role in directing learning throughout the lifespan. Prior work finds that violations of expectations can be powerful triggers of curiosity in both children and adults, but it is unclear which expectation-violating events induce the greatest curiosity and how this might vary over development. Some theories have suggested a U-shaped function such that stimuli of moderate extremity pique the greatest curiosity. However, expectation-violations vary not only in degree, but in kind: for example, some things violate an intuitive theory (e.g., an alligator that can talk) and others are merely unlikely (e.g., an alligator hiding under your bed). Combining research on curiosity with distinctions posited in the cognitive science of religion, we test whether minimally counterintuitive (MCI) stimuli, which involve one violation of an intuitive theory, are especially effective at triggering curiosity. We presented adults (N = 77) and 4- and 5-year-olds (N = 36) in the United States with stimuli that were ordinary, unlikely, MCI, and very counterintuitive (VCI) and asked which one they would like to learn more about. Adults and 5-year-olds chose Unlikely over Ordinary and MCI over Unlikely, but not VCI over MCI, more often than chance. Our results suggest that (i) minimally counterintuitive stimuli trigger greater curiosity than merely unlikely stimuli, (ii) surprisingness has diminishing returns, and (iii) sensitivity to surprisingness increases with age, appearing in our task by age 5.
The efficacy of red onion peel methanol extract to prevent dry rot in potato tubers caused by Fusarium sambucinum was investigated. At 20 mg mL-1 , the methanol extract caused a great decrease in the fungal growth and spore germination by 86.3 %, and 91.2 %, respectively. Also, the dry rot control efficacy in potato slices inoculated with F. sambucinum reached 91.8 % at the same concentration. The treatment with methanol extract significantly increased the total phenolics to 0.31 g kg − 1 compared with the control (0.19 g kg − 1) in potato slices on the fourth day of the storage period as well as the increase in the level of total flavonoids. The relative leakage rate was 46.3 % in treated potato tuber slices compared to the control by 76.5 % and MDA content was much lower in slices treated compared with control slices during four days of storage. The methanol extract enhanced the activity of phenylalanine ammonia-lyase (PAL), polyphenoloxidase (PPO), catalase (CAT), and peroxidase (POD) in potato slices throughout the experiment. The major compounds in the methanol extract were the flavonoids rutin, quercetin triglucoside, ferulic acid, quercetin diglucoside, quercetin monoglucoside, iso-rhamnetin glucoside, quercetin, kaempferol, and isorhamnetin using HPLC-UV/DAD, QTOF, and NMR spectra (1 H NMR, APT, HSQC, COSY, HMBC, and NOESY).
This paper studies when and why firms prefer more direct forms of state capture (i.e., directly capturing tenured state officials who implement policy, as bureaucrats) to more indirect ones (i.e., using intermediaries, such as elected officials, to influence bureaucrats). First, we propose a principal–agent model under political uncertainty. Firms can induce market distortions by making transfers to incumbents, but such incumbents may be displaced in an election. Direct capture acts as an insurance for the firm, guaranteeing that its paid for distortions are kept in place even when the incumbent loses. We then show that policies thought to decrease state capture, such as improved bureaucrat selection, can have little to no effect once substitution towards indirect control is accounted for. We test the model’s predictions using a novel database on contractual arrangements between politicians, political brokers and businessmen in Benin. As proposed by the theory, we find that an increase in political uncertainty is associated with an increase in direct forms of capture. We conclude that electoral competition is not a sufficient mechanism to curb firms’ control of government when they can switch forms of state capture.
Solar generation can become a major and global source of clean energy by 2050. Nevertheless, few studies have assessed its resilience to extreme events, and none have used empirical data to characterize the fragility of solar panels. This paper develops fragility functions for rooftop and ground-mounted solar panels calibrated with solar panel structural performance data in the Caribbean for Hurricanes Irma and Maria in 2017 and Hurricane Dorian in 2019. After estimating the hurricane wind fields, we follow a Bayesian approach to estimate fragility functions for rooftop and ground-mounted panels based on the observations supplemented with existing numerical studies on solar panel vulnerability. Next, we apply the developed fragility functions to assess failure rates due to hurricane hazards in Miami-Dade, Florida, highlighting that the panels perform below the code requirements, especially rooftop panels. We also illustrate that strength increases can improve the panels' structural performance effectively. However, strength increases by a factor of two still cannot meet the reliability stated in the code.
We establish the existence and uniqueness of a solution to the master equation for a mean field game of controls with absorption. The mean field game arises as a continuum limit of a dynamic game of exhaustible resources modeling Cournot competition between producers. The proof relies on an analysis of a forward-backward system of nonlocal Hamilton-Jacobi/Fokker-Planck equations with Dirichlet boundary conditions. In particular, we establish new a priori estimates to prove that solutions are differentiable with respect to the initial measure.
In this study, a structural response estimation method for evaluating the long-term strain, which can serve as the basis of assessing structural safety of concrete structures, is presented. Characteristics of short-term deformation caused by environmental influences and long-term inelastic deformation caused by combination of rheological effects and environmental influences are identified. To reflect these time-dependent short- and long-term deformation characteristics in the proposed method, the strain and corresponding time information collected from a structural health monitoring (SHM) are used. In the proposed method, the relationship between a strain response measured from a concrete structure and the corresponding time information including the year, month, day, and hour is defined by a convolutional neural network (CNN), which is a deep learning technique. The method assumes that the main sources of the strain in the structure are environmental influences, such as temperature and humidity, which have daily and seasonal periodicity, and rheological effects in concrete, such as creep and shrinkage, but it also assumes that the quantitative information on these sources is not available (e.g., environmental temperature and humidity, and rheological strain were not reliably measured). Thus, the CNN method developed in this study is trained only with strain and time data collected over several years, and used to estimate strain values within a specific timeframe, e.g., when the safety evaluation of the concrete structure is required or in case of SHM system failure or data loss. The presented method was developed and validated using SHM data from a real structure instrumented with fiber optic strain sensors. In addition, exploration of the constitution of the input of the CNN identified the type of time information that is the most effective in the long-term strain estimation of the developed method.
This book is a philosophical exploration of bias and our practices of attributing it. It develops and defends the norm-theoretic account of bias, according to which objectionable biases involve systematic departures from objective norms or standards of correctness. It explores the perspectival character of bias attributions, or the ways in which our views about which people and sources of information are biased about a topic are influenced and constrained, both rationally and psychologically, by our views about the topic itself. The book defends a robust pluralism about bias, according to which a radical diversity of things are genuinely biased, with none of these more fundamental than all of the rest. Biases of people are understood as multiply realizable dispositions to depart from objective norms. It offers a novel account of the bias blind spot, or our tendency to fail to see bias in ourselves in a way that we see it in others. It explores the connections between bias and central topics in the theory of knowledge, including truth, knowledge, rationality, reliability, introspection, skepticism, and disagreement. A number of racial conclusions are defended: that both rationality and morality sometimes require us to be biased; that in many cases of disagreement, we are rationally required to view those who disagree with us as biased, even if we know nothing about how they arrived at their views or why they hold them; and that even God could not have made us reliable detectors of our own biases through introspection.
Within “mainstream” developmental science, gender researchers largely study the developmental trajectory of children considered to be “gender typical,” while research housed primarily in psychiatry and clinical psychology often documents the trajectories of gender diverse children. This article aims to bridge the studies of gender diversity and “mainstream” gender development. First, we review literature on the development of four commonly studied subgroups of gender diverse children—children referred to medical clinics because of their gender identity and expression, transgender children, female children with congenital adrenal hyperplasia, and tomboys—highlighting how these gender trajectories do or do not align with modal developmental patterns. We then describe social, cognitive, and biological determinants of gender in light of their implications for understanding diverse gender development. Finally, we note methodological suggestions for future research, with an eye toward better integrating research on gender diversity into “mainstream” gender development research. Expected final online publication date for the Annual Review of Developmental Psychology, Volume 4 is December 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Miscalculating the volumes of water withdrawn for irrigation, the largest consumer of freshwater in the world, jeopardizes sustainable water management. Hydrological models quantify water withdrawals, but their estimates are unduly precise. Model imperfections need to be appreciated to avoid policy misjudgements.
The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about the fundamental theory of nature at play in the extreme gravity regime, where the gravitational interaction is both strong and dynamical. In this white paper, the Fundamental Physics Working Group of the LISA Consortium summarizes the current topics in fundamental physics where LISA observations of gravitational waves can be expected to provide key input. We provide the briefest of reviews to then delineate avenues for future research directions and to discuss connections between this working group, other working groups and the consortium work package teams. These connections must be developed for LISA to live up to its science potential in these areas.
This paper studies optimal subcarrier permutation in hybrid power line/wireless systems to either maximize the achievable data rate or minimize the average bit error probability (BEP). In order to better exploit the frequency selectivity of power line and wireless media, subcarrier permutation is optimized under uniform or optimal power allocation over an orthogonal frequency-division multiplexing scheme using maximal-ratio combining. Different from previous works, we demonstrate that the normalized signal-to-noise (nSNR) must be considered instead of the SNR and prove that it can be extended to cases where the minimization of the average BEP and optimal power allocation are considered. Moreover, we show that subcarrier permutation and power allocation problems can be assumed to be decoupled. Numerical results show that performance gains associated with subcarrier permutation become more relevant as the frequency selectivity of the nSNRs increases. In addition, the optimal subcarrier permutation is more effective for minimizing the average BEP than maximizing the achievable data rate and yields similar improvement under the usage of uniform and optimal power allocations.
This article investigates the matrix coupled “all-in-one” magnetic structure that combines both series coupling and parallel coupling for pulse-width modulated (PWM) power conversion. A systematic analysis of the current ripple reduction mechanism is performed. Current ripple steering among asymmetric series coupled windings is discussed. The transient performance of the matrix coupled inductor is demystified, providing insights for analyzing converter dynamics and its large- or small-signal modeling. To quantify the benefits of matrix coupling, a figure of merit is defined by comparing the current ripple of a matrix coupled inductor to that of a discrete inductor given the same transient speed. The comparison results indicate that a higher number of phases and a stronger matrix coupling coefficient amplify the benefits of matrix coupling. A 1 V-to-5 V input, 1 V-to-5 V output, four-phase matrix coupled synchronous SEPIC converter with planar PCB integrated magnetics is built and tested. The matrix coupled SEPIC prototype can support load current up to 185 A at 5 V-to-1 V voltage conversion with a maximum power density over 470 W/in $^\text{3}$ . Compared to commercial discrete inductors, the matrix coupled inductor has a 5.6 times smaller size and 8.5 times faster transient speed with similar current ripple and current rating. The experimental results validate the matrix coupling concept and the theoretical analysis, opening the possibilities toward wide adoption of ‘‘all-in-one-magnetics” in PWM topologies.
Telemedicine may provide equitable, accessible, and affordable healthcare to individuals globally. Recently tele-medicine has emerged as a vital resource for interdisciplinary healthcare professionals to provide critical medical care on the frontlines during the combined COVID-19 pandemic and the drug and opioid crisis. With the recent 2020 expansion of insurance coverage of telemedicine services by the United States Centers for Medicare & Medicaid Services, there has been an uptick in the need to understand how to comprehensively train physicians and health care professionals on telemedicine during a public health crisis. This study gathered 98 survey responses from interdisciplinary healthcare professionals regarding their telemedicine experience, focusing on trends of use with the drug and opioid crisis during the COVID-19 pandemic. The results demonstrate that during the COVID-19 pandemic, telemedicine provided a novel, innovative way to address an unmet need in healthcare and may aid to improve safe medication stewardship (SaMS) practice guidelines. Further expanded population-based research and randomized clinical trials are necessary to confirm these preliminary recommendations and form best practices for use in digital health and telemedicine. In addition, further studies will confirm the benefits of interdisciplinary healthcare professionals’ engagement in harm reduction strategies via telemedicine to address improving safe medication use.
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7,154 members
• Department of Molecular Biology
• Department of Operations Research and Financial Engineering
• Princeton Plasma Physics Laboratory
• Department of Ecology and Evolutionary Biology
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