Relational diversity in social portfolios predicts well-being.

We document a link between the relational diversity of one's social portfolio-the richness and evenness of relationship types across one's social interactions-and well-being. Across four distinct samples, respondents from the United States who completed a preregistered survey (n = 578), respondents to the American Time Use Survey (n = 19,197), respondents to the World Health Organization's Study on Global Aging and Adult Health (n = 10,447), and users of a French mobile application (n = 21,644), specification curve analyses show that the positive relationship between social portfolio diversity and well-being is robust across different metrics of well-being, different categorizations of relationship types, and the inclusion of a wide range of covariates. Over and above people's total amount of social interaction and the diversity of activities they engage in, the relational diversity of their social portfolio is a unique predictor of well-being, both between individuals and within individuals over time.

Pan-African evolution of within- and between-country COVID-19 dynamics.

The coronavirus disease 2019 (COVID-19) pandemic is heterogeneous throughout Africa and threatening millions of lives. Surveillance and short-term modeling forecasts are critical to provide timely information for decisions on control strategies. We created a strategy that helps predict the country-level case occurrences based on cases within or external to a country throughout the entire African continent, parameterized by socioeconomic and geoeconomic variations and the lagged effects of social policy and meteorological history. We observed the effect of the Human Development Index, containment policies, testing capacity, specific humidity, temperature, and landlocked status of countries on the local within-country and external between-country transmission. One-week forecasts of case numbers from the model were driven by the quality of the reported data. Seeking equitable behavioral and social interventions, balanced with coordinated country-specific strategies in infection suppression, should be a continental priority to control the COVID-19 pandemic in Africa.

From disks to channels: dynamics of active nematics confined to an annulus.

Confinement can be used to systematically tame turbulent dynamics occurring in active fluids. Although periodic channels are the simplest geometries to study confinement numerically, the corresponding experimental realizations require closed racetracks. Here, we computationally study 2D active nematics confined to such a geometry-an annulus. By systematically varying the annulus inner radius and channel width, we bridge the behaviors observed in the previously studied asymptotic limits of the annulus geometry: a disk and an infinite channel. We identify new steady-state behaviors, which reveal the influence of boundary curvature and its interplay with confinement. We also show that, below a threshold inner radius, the dynamics are insensitive to the presence of the inner hole. We explain this insensitivity through a simple scaling analysis. Our work sheds further light on design principles for using confinement to control the dynamics of active nematics.

Exact Coherent Structures and Phase Space Geometry of Preturbulent 2D Active Nematic Channel Flow.

Confined active nematics exhibit rich dynamical behavior, including spontaneous flows, periodic defect dynamics, and chaotic "active turbulence." Here, we study these phenomena using the framework of exact coherent structures, which has been successful in characterizing the routes to high Reynolds number turbulence of passive fluids. Exact coherent structures are stationary, periodic, quasiperiodic, or traveling wave solutions of the hydrodynamic equations that, together with their invariant manifolds, serve as an organizing template of the dynamics. We compute the dominant exact coherent structures and connecting orbits in a preturbulent active nematic channel flow, which enables a fully nonlinear but highly reduced-order description in terms of a directed graph. Using this reduced representation, we compute instantaneous perturbations that switch the system between disparate spatiotemporal states occupying distant regions of the infinite-dimensional phase space. Our results lay the groundwork for a systematic means of understanding and controlling active nematic flows in the moderate- to high-activity regime.

Opportunity Neglect: An Aversion to Low-Probability Gains.

Seven preregistered studies (N = 2,890, adult participants) conducted in the field, in the lab, and online documented opportunity neglect: a tendency to reject opportunities with low probability of success even when they come with little or no objective cost (e.g., time, money, reputation). Participants rejected a low-probability opportunity in an everyday context (Study 1). Participants also rejected incentive-compatible gambles with positive expected value-for both goods (Study 2) and money (Studies 3-7)-even with no possibility of monetary loss and nontrivial rewards (e.g., a 1% chance at $99). Participants rejected low-probability opportunities more frequently than high-probability opportunities with equal expected value (Study 3). Although taking some real-life opportunities comes with costs, we show that people are even willing to incur costs to opt out of low-probability opportunities (Study 4). Opportunity neglect can be mitigated by highlighting that rejecting an opportunity is equivalent to choosing a zero probability of success (Studies 6-7).

Self-organized dynamics and the transition to turbulence of confined active nematics.

We study how confinement transforms the chaotic dynamics of bulk microtubule-based active nematics into regular spatiotemporal patterns. For weak confinements in disks, multiple continuously nucleating and annihilating topological defects self-organize into persistent circular flows of either handedness. Increasing confinement strength leads to the emergence of distinct dynamics, in which the slow periodic nucleation of topological defects at the boundary is superimposed onto a fast procession of a pair of defects. A defect pair migrates toward the confinement core over multiple rotation cycles, while the associated nematic director field evolves from a distinct double spiral toward a nearly circularly symmetric configuration. The collapse of the defect orbits is punctuated by another boundary-localized nucleation event, that sets up long-term doubly periodic dynamics. Comparing experimental data to a theoretical model of an active nematic reveals that theory captures the fast procession of a pair of [Formula: see text] defects, but not the slow spiral transformation nor the periodic nucleation of defect pairs. Theory also fails to predict the emergence of circular flows in the weak confinement regime. The developed confinement methods are generalized to more complex geometries, providing a robust microfluidic platform for rationally engineering 2D autonomous flows.

IDENTIFIABILITY OF INFECTION MODEL PARAMETERS EARLY IN AN EPIDEMIC.

It is known that the parameters in the deterministic and stochastic SEIR epidemic models are structurally identifiable. For example, from knowledge of the infected population time series I(t) during the entire epidemic, the parameters can be successfully estimated. In this article we observe that estimation will fail in practice if only infected case data during the early part of the epidemic (prepeak) is available. This fact can be explained using a well-known phenomenon called dynamical compensation. We use this concept to derive an unidentifiability manifold in the parameter space of SEIR that consists of parameters indistinguishable from I(t) early in the epidemic. Thus, identifiability depends on the extent of the system trajectory that is available for observation. Although the existence of the unidentifiability manifold obstructs the ability to exactly determine the parameters, we suggest that it may be useful for uncertainty quantification purposes. A variant of SEIR recently proposed for COVID-19 modeling is also analyzed, and an analogous unidentifiability surface is derived.

Multiscale Microtubule Dynamics in Active Nematics.

In microtubule-based active nematics, motor-driven extensile motion of microtubule bundles powers chaotic large-scale dynamics. We quantify the interfilament sliding motion both in isolated bundles and in a dense active nematic. The extension speed of an isolated microtubule pair is comparable to the molecular motor stepping speed. In contrast, the net extension in dense 2D active nematics is significantly slower; the interfilament sliding speeds are widely distributed about the average and the filaments exhibit both contractile and extensile relative motion. These measurements highlight the challenge of connecting the extension rate of isolated bundles to the multimotor and multifilament interactions present in a dense 2D active nematic. They also provide quantitative data that is essential for building multiscale models.

Machine learning forecasting of active nematics.

Active nematics are a class of far-from-equilibrium materials characterized by local orientational order of force-generating, anisotropic constitutes. Traditional methods for predicting the dynamics of active nematics rely on hydrodynamic models, which accurately describe idealized flows and many of the steady-state properties, but do not capture certain detailed dynamics of experimental active nematics. We have developed a deep learning approach that uses a Convolutional Long-Short-Term-Memory (ConvLSTM) algorithm to automatically learn and forecast the dynamics of active nematics. We demonstrate our purely data-driven approach on experiments of 2D unconfined active nematics of extensile microtubule bundles, as well as on data from numerical simulations of active nematics.

Optimal Control of Active Nematics.

In this work we present the first systematic framework to sculpt active nematic systems, using optimal control theory and a hydrodynamic model of active nematics. We demonstrate the use of two different control fields, (i) applied vorticity and (ii) activity strength, to shape the dynamics of an extensile active nematic that is confined to a disk. In the absence of control inputs, the system exhibits two attractors, clockwise and counterclockwise circulating states characterized by two co-rotating topological +1/2 defects. We specifically seek spatiotemporal inputs that switch the system from one attractor to the other; we also examine phase-shifting perturbations. We identify control inputs by optimizing a penalty functional with three contributions: total control effort, spatial gradients in the control, and deviations from the desired trajectory. This work demonstrates that optimal control theory can be used to calculate nontrivial inputs capable of restructuring active nematics in a manner that is economical, smooth, and rapid, and therefore will serve as a guide to experimental efforts to control active matter.

Tackling the Challenge of Packaging Plastic in the Environment.

How to solve a problem like man-made plastics? In this Science Voices article, Dr. Michael Norton, Programme Director of the European Academies Science Advisory Council (EASAC) summarizes a recent report on the challenges and progresses concerning plastics in the environment.

Experience with a "Feed and Swaddle" program in infants up to six months of age.

BACKGROUND: Feed and swaddle is a technique in which an infant is fed and allowed to fall asleep to facilitate diagnostic imaging. This study reviews our experience and diagnostic success in premature and term infants up to 6 months old undergoing brain magnetic resonance imaging (MRI) using a feed and swaddle technique and with comparable patients imaged under anesthesia. METHODS: We reviewed the charts of all infants ≤6 months who underwent brain MRI at our institution between 1 January 2013 and 31 March 2016. We recorded and analyzed demographic information, scan indication, scan length, prematurity status, anesthetic technique if used, complications, and diagnostic success or failure. RESULTS: One hundred and sixty-four term infants underwent brain MRI using a feed and swaddle technique. The success rate in term infants <90 days was 91.1% (113/124) versus 95.0% (38/40) in infants ≥90 days and ≤181 days old. Fifty-three premature infants underwent feed and swaddle for brain MRI with a diagnostic success rate of 92.5% (49/53). No complications were noted in any feed and swaddle patients. Those who received anesthesia had a diagnostic success rate of 100% (70/70) but experienced complications including hypoxemia, 14.3% (10/70); hypothermia, 18.9% (10/53); bradycardia, 10.1% (7/69); and hypotension, 4.2% (3/70). CONCLUSION: Given the high rate of success and absence of complications with feed and swaddle in children ≤6 months for brain MRI and the presence of anesthesia-related complications, most infants should undergo a trial of feed and swaddle prior to undergoing brain MRI with anesthesia.

Buying time promotes happiness.

Around the world, increases in wealth have produced an unintended consequence: a rising sense of time scarcity. We provide evidence that using money to buy time can provide a buffer against this time famine, thereby promoting happiness. Using large, diverse samples from the United States, Canada, Denmark, and The Netherlands (n = 6,271), we show that individuals who spend money on time-saving services report greater life satisfaction. A field experiment provides causal evidence that working adults report greater happiness after spending money on a time-saving purchase than on a material purchase. Together, these results suggest that using money to buy time can protect people from the detrimental effects of time pressure on life satisfaction.

Dynamics of Reaction-Diffusion Oscillators in Star and other Networks with Cyclic Symmetries Exhibiting Multiple Clusters.

We experimentally and theoretically investigate the dynamics of inhibitory coupled self-driven oscillators on a star network in which a single central hub node is connected to k peripheral arm nodes. The system consists of water-in-oil Belousov-Zhabotinsky ∼100 µm emulsion drops contained in storage wells etched in silicon wafers. We observed three dynamical attractors by varying the number of arms in the star graph and the coupling strength: (i) unlocked, uncorrelated phase shifts between all oscillators; (ii) locked, arm hubs synchronized in phase with a k-dependent phase shift between the arm and central hub; and (iii) center silent, a central hub stopped oscillating and the arm hubs oscillated without synchrony. We compare experiment to theory. For case (ii), we identified a logarithmic dependence of the phase shift on star degree, and were able to discriminate between contributions to the phase shift arising from star topology and oscillator chemistry.

Microtargeting for conservation.

Widespread human action and behavior change is needed to achieve many conservation goals. Doing so at the requisite scale and pace will require the efficient delivery of outreach campaigns. Conservation gains will be greatest when efforts are directed toward places of high conservation value (or need) and tailored to critical actors. Recent strategic conservation planning has relied primarily on spatial assessments of biophysical attributes, largely ignoring the human dimensions. Elsewhere, marketers, political campaigns, and others use microtargeting-predictive analytics of big data-to identify people most likely to respond positively to particular messages or interventions. Conservationists have not yet widely capitalized on these techniques. To investigate the effectiveness of microtargeting to improve conservation, we developed a propensity model to predict restoration behavior among 203,645 private landowners in a 5,200,000 ha study area in the Chesapeake Bay Watershed (U.S.A.). To isolate the additional value microtargeting may offer beyond geospatial prioritization, we analyzed a new high-resolution land-cover data set and cadastral data to identify private owners of riparian areas needing restoration. Subsequently, we developed and evaluated a restoration propensity model based on a database of landowners who had conducted restoration in the past and those who had not (n = 4978). Model validation in a parallel database (n = 4989) showed owners with the highest scorers for propensity to conduct restoration (i.e., top decile) were over twice as likely as average landowners to have conducted restoration (135%). These results demonstrate that microtargeting techniques can dramatically increase the efficiency and efficacy of conservation programs, above and beyond the advances offered by biophysical prioritizations alone, as well as facilitate more robust research of many social-ecological systems.

Micro-focalización para la Conservación Resumen Se necesitan acciones humanas diseminadas y un cambio en el comportamiento para lograr muchos objetivos de conservación. Que se logre esto a la escala y al ritmo requerido requerirá de la entrega eficiente de las campañas de participación. Las ganancias de la conservación serán mayores cuando los esfuerzos estén dirigidos hacia sitios con un alto valor (o necesidad) de conservación y estén personalizados para los actores más importantes. La reciente planeación estratégica de la conservación ha dependido principalmente de las evaluaciones espaciales de los atributos biofísicos, ignorando generalmente las dimensiones humanas. En otros ámbitos, los mercadólogos, las campañas políticas, así como otros, usan la micro-focalización - el análisis predictivo de datos masivos - para identificar a las personas con mayor probabilidad de responder positivamente a mensajes o intervenciones particulares. Los conservacionistas todavía no han capitalizado extensamente estas técnicas. Desarrollamos un modelo de tendencia para predecir el comportamiento de restauración entre 203,645 terratenientes privados en un área de estudio de 5,200,000 ha en la cuenca de la Bahía de Chesapeake (E.U.A.) y así investigar la eficiencia de la micro-focalización en el aumento de la conservación. Para aislar el valor adicional que puede ofrecer la micro-focalización más allá de la priorización geoespacial, analizamos un nuevo conjunto de alta resolución de datos sobre la cobertura del suelo y datos catastrales para identificar a los terratenientes privados de áreas ribereñas que necesitan restauración. Después de esto, desarrollamos y evaluamos el modelo de tendencia a la restauración basado en una base de datos de terratenientes que han realizado restauraciones en el pasado y aquellos que no (n = 4,978). La validación del modelo en una base de datos paralela (n = 4,989) mostró que los terratenientes con los puntajes más altos para la tendencia a la restauración (es decir, el decil superior) tenían el doble de probabilidad de haber realizado acciones de conservación que el terrateniente promedio (135%). Estos resultados muestran que las técnicas de micro-focalización pueden incrementar dramáticamente la eficiencia y la eficacia de los programas de conservación, más allá de los avances ofrecidos sólo por las priorizaciones biofísicas, así como facilitar la investigación más sólida sobre muchos sistemas socio-ecológicos.

Physical and situational inequality on airplanes predicts air rage.

We posit that the modern airplane is a social microcosm of class-based society, and that the increasing incidence of "air rage" can be understood through the lens of inequality. Research on inequality typically examines the effects of relatively fixed, macrostructural forms of inequality, such as socioeconomic status; we examine how temporary exposure to both physical and situational inequality, induced by the design of environments, can foster antisocial behavior. We use a complete set of all onboard air rage incidents over several years from a large, international airline to test our predictions. Physical inequality on airplanes-that is, the presence of a first class cabin-is associated with more frequent air rage incidents in economy class. Situational inequality-boarding from the front (requiring walking through the first class cabin) versus the middle of the plane-also significantly increases the odds of air rage in both economy and first class. We show that physical design that highlights inequality can trigger antisocial behavior on airplanes. More broadly, these results point to the importance of considering the design of environments-from airplanes to office layouts to stadium seating-in understanding both the form and emergence of antisocial behavior.

Hiding personal information reveals the worst.

Seven experiments explore people's decisions to share or withhold personal information, and the wisdom of such decisions. When people choose not to reveal information--to be "hiders"--they are judged negatively by others (experiment 1). These negative judgments emerge when hiding is volitional (experiments 2A and 2B) and are driven by decreases in trustworthiness engendered by decisions to hide (experiments 3A and 3B). Moreover, hiders do not intuit these negative consequences: given the choice to withhold or reveal unsavory information, people often choose to withhold, but observers rate those who reveal even questionable behavior more positively (experiments 4A and 4B). The negative impact of hiding holds whether opting not to disclose unflattering (drug use, poor grades, and sexually transmitted diseases) or flattering (blood donations) information, and across decisions ranging from whom to date to whom to hire. When faced with decisions about disclosure, decision-makers should be aware not just of the risk of revealing, but of what hiding reveals.

A review on nanomaterial-based field effect transistor technology for biomarker detection.

Field effect transistor (FET) based sensors have attractive features such as small size, ease of mass production, high versatility and comparably low costs. Over the last decade, many FET type biosensors based on various nanomaterials (e.g. silicon nanowires, graphene, and transition metal dichalcogenides) have been developed to detect various classes of biomolecular targets due to their integration into portable and rapid test systems, both for use in the clinical lab and in point-of-care testing. This review (with 197 refs.) starts with an introduction into the specific features of FET biosensor technology. This is followed by a description of the essentials of methods for immobilization of recognition elements. The next section discusses the progress that has been made in FET based biosensors using semiconducting nanostructures composed of silicon, graphene, metal oxides, and transition metal dichalcogenides. A further section is devoted to microfluidic systems combined with FET biosensors. We then emphasize the biosensing applications of these diagnostic devices for analysis of clinically relevant biomarkers, specifically to sensing of neurotransmitters, metabolites, nucleic acids, proteins, cancer and cardiac biomarkers. Two tables are presented which summarize advances in applications of 1D and 2D nanomaterial-based FETs for biomarker sensing. A concluding section summarizes the current status, addresses current challenges, and gives perspective trends for the field. Graphical abstract Field effect transistor devices based on the use of 1D and 2D semiconductor nanostructures (so called nano-FETs) are making use of materials including silicon nanowires, graphene, zinc oxide, indium oxide, titanium oxide, and molybdenum disulfide that are further modified with recognition elements for biosensing application.

The Sapphire (0001) Surface: A Transparent and Ultraflat Substrate for DNA Nanostructure Imaging.

Mica is the current substrate of choice for DNA nanostructure imaging, mainly due to its atomically flat surface. However, these mica substrates are often not optically clear. In this work, sapphire has been evaluated as an alternative substrate, with potential to enable parallel optical and AFM studies. Well known for its thermal and chemical properties, sapphire is a hard ionic material with excellent optical properties. Because sapphire lacks the excellent basal cleavage properties of the sheet silicate mica, a process to anneal it at high temperature in water vapor was developed to achieve near atomically smooth (average roughness = 0.141 nm) terraces. AFM imaging was used to determine the dimensions of these terraces and to characterize the morphology of the DNA nanostructures, revealing that their structures were preserved, indicating that annealed c-plane cut (0001) sapphire is a promising substitute for mica as a flat and transparent substrate for DNA nanostructure studies.

The Belief in a Favorable Future.

People believe that future others' preferences and beliefs will change to align with their own. People holding a particular view (e.g., support of President Trump) are more likely to believe that future others will share their view than to believe that future others will have an opposing view (e.g., opposition to President Trump). Six studies demonstrated this belief in a favorable future (BFF) for political views, scientific beliefs, and entertainment and product preferences. BFF is greater in magnitude than the tendency to believe that current others share one's views (false-consensus effect), arises across cultures, is distinct from general optimism, is strongest when people perceive their views as being objective rather than subjective, and can affect (but is distinct from) beliefs about favorable future policy changes. A lab experiment involving monetary bets on the future popularity of politicians and a field experiment involving political donations ( N = 660,542) demonstrated that BFF can influence people's behavior today.