Observation of the effect of gravity on the motion of antimatter.

Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.

Laser cooling of antihydrogen atoms.

The photon-the quantum excitation of the electromagnetic field-is massless but carries momentum. A photon can therefore exert a force on an object upon collision1. Slowing the translational motion of atoms and ions by application of such a force2,3, known as laser cooling, was first demonstrated 40 years ago4,5. It revolutionized atomic physics over the following decades6-8, and it is now a workhorse in many fields, including studies on quantum degenerate gases, quantum information, atomic clocks and tests of fundamental physics. However, this technique has not yet been applied to antimatter. Here we demonstrate laser cooling of antihydrogen9, the antimatter atom consisting of an antiproton and a positron. By exciting the 1S-2P transition in antihydrogen with pulsed, narrow-linewidth, Lyman-α laser radiation10,11, we Doppler-cool a sample of magnetically trapped antihydrogen. Although we apply laser cooling in only one dimension, the trap couples the longitudinal and transverse motions of the anti-atoms, leading to cooling in all three dimensions. We observe a reduction in the median transverse energy by more than an order of magnitude-with a substantial fraction of the anti-atoms attaining submicroelectronvolt transverse kinetic energies. We also report the observation of the laser-driven 1S-2S transition in samples of laser-cooled antihydrogen atoms. The observed spectral line is approximately four times narrower than that obtained without laser cooling. The demonstration of laser cooling and its immediate application has far-reaching implications for antimatter studies. A more localized, denser and colder sample of antihydrogen will drastically improve spectroscopic11-13 and gravitational14 studies of antihydrogen in ongoing experiments. Furthermore, the demonstrated ability to manipulate the motion of antimatter atoms by laser light will potentially provide ground-breaking opportunities for future experiments, such as anti-atomic fountains, anti-atom interferometry and the creation of antimatter molecules.

Plant-mediated synthesis of Mn3O4nanoparticles: challenges and applications.

This review focuses on the green synthesis methods, challenges, and applications of manganese oxide (Mn3O4) nanoparticles investigated in the past five years. Mn3O4nanoparticles offer some unique properties that are attributed in part to the presence of mixed oxidation states of manganese (i.e. +2 and +3) in the particle, which can be utilized in a wide range of redox-sensitive applications, such as in developing supercapacitive energy storage materials. In addition, the green synthesis of Mn3O4nanoparticles through plant extracts has potential uses in sustainable nanotechnology. Various plant extract-mediated synthesis techniques for Mn3O4nanoparticles have been investigated and presented. By comparing the size and structure of the synthesized Mn3O4nanoparticles, we have observed a consistent pattern of obtaining spherical particles with a size ranging from 16 to 50 nm. The morphology of the generated Mn3O4nanoparticles can be influenced by the annealing temperature and the composition of the plant extract used during the nanoparticle synthesis. Additionally, numerous applications for the greenly produced Mn3O4nanoparticles have been demonstrated. Mn3O4nanoparticles derived from plant extracts have been found to possess antimicrobial properties, supercapacitive and electrochemical capabilities, and excellent pollutant degradation efficiency. However, the magnetic properties of these nanoparticles synthesized by plant extracts are yet to be explored for potential biomedical applications. Finally, challenges to existing synthetic methods and future perspectives on the potential applications of these green synthesized Mn3O4nanoparticles are highlighted.

Observation of the 1S-2P Lyman-α transition in antihydrogen.

In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-α line-the 1S-2P transition at a wavelength of 121.6 nanometres-have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called 'Lyman-α forest'3 of absorption lines at different redshifts. Here we report the observation of the Lyman-α transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S-2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10-8. Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter and antimatter. Alongside the ground-state hyperfine4,5 and 1S-2S transitions6,7 recently observed in antihydrogen, the Lyman-α transition will permit laser cooling of antihydrogen8,9, thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements10. In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.

Erratum: Observation of the hyperfine spectrum of antihydrogen.

This corrects the article DOI: 10.1038/nature23446.

Characterization of the 1S-2S transition in antihydrogen.

In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron 2 (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter3-7, including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed 8 in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 × 1015 hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 × 10-12-two orders of magnitude more precise than the previous determination 8 -corresponding to an absolute energy sensitivity of 2 × 10-20 GeV.

Violent deaths among individuals subject to domestic violence protection orders in King County, Washington, USA, 2014-2020.

OBJECTIVES: Individuals (ie, respondents) subject to domestic violence protection orders have threatened or engaged in one form of violence perpetration and may be at increased risk for experiencing others forms of violence, including violent death. METHODS: Using a cohort of granted domestic violence protection orders in King County, Washington, USA, from 2014 to 2020 (n=3543), we calculated standardised mortality ratios for violent death, including suicide, homicide, legal intervention and undetermined intent, comparing domestic violence protection order respondents to King County residents adjusting for year, age, sex, and race and ethnicity through indirect standardisation. RESULTS: There were 66 deaths among domestic violence protection order respondents; 25.8% were violent deaths and 52.9% of violent deaths involved firearms. The standardised mortality ratio for violent death was 3.71 (95% CI: 2.16 to 5.93) among domestic violence protection order respondents compared with King County residents. CONCLUSION: The domestic violence protection order process may provide an opportunity for referrals to services to address shared risk factors for violence perpetration and victimisation.

Young Adult Alcohol and Cannabis Impaired Driving After the Opening of Cannabis Retail Stores in Washington State.

Motor vehicle crashes are a leading cause of death for young adults (YA) in the USA, and driving under the influence of alcohol (DUIA), cannabis (DUIC), and simultaneous use of both substances (DUIAC) are prominent risk factors. Trends in YA impaired driving behaviors after opening of cannabis retail stores have been understudied. We examined YA trends in DUIA, DUIC, and DUIAC from immediately prior through 5 years following the opening of cannabis retail outlets in Washington State (2014-2019). Differences in trends were assessed across age, sex, and urbanicity. Weighted logistic regressions assessed yearly change in prevalence of DUIA, DUIC, and DUIAC from 2014 to 2019, using annual statewide data from the Washington Young Adult Health Survey (n = 12,963; ages 18-25). Moderation of trends by age, sex, and urbanicity was assessed. Prevalence of DUIA decreased overall (AOR = 0.93, 95% CI 0.90, 0.97) and among drinkers (AOR = 0.95, 95% CI 0.91, 0.99) but remained at concerning levels in 2019 (10% overall; 16% among drinkers). Overall DUIC did not change significantly (AOR = 0.99, 95% CI 0.96, 1.03; 11% by 2019) but decreased among those who used cannabis (AOR = 0.91, 95% CI 0.86, 0.96; 33% by 2019). DUIAC decreased but not significantly (overall: AOR = 0.89, 95% CI 0.78, 1.01; those who used alcohol and cannabis: AOR = 0.84, 95% CI 0.74, 1.04). Prevalence of YA DUI remained concerning. Trends may reflect some success in reducing DUI, but additional detection and prevention are needed.

Do Self-Processes and Parenting Mediate the Effects of Anxious Parents' Psychopathology on Youth Depression and Suicidality?

To understand how anxious parents' global psychopathology increases children's risks for depression and suicidality, we tested mediational pathways through which parent global psychopathology was associated with youth depression and suicidality over a six-year period. Parents (n = 136) who had an anxiety disorder at baseline reported global psychopathology and youth internalizing problems. Youth did not have any psychiatric disorder at baseline and they reported self-esteem, perceived control, and perceived parental warmth and rejection at baseline and 1-year follow-up. At 6-year follow-up, youth depression and suicidality were assessed via multiple reporters including the self, parent, and/or an independent evaluator. Results showed that parental psychopathology had an indirect but not direct effect on youth depression and suicidality via perceived control. No associations were found for the other hypothesized mediators. Perceived control might be a transdiagnostic intervention target in depression and suicide prevention programs for youth exposed to parental anxiety.

Observation of the 1S-2S transition in trapped antihydrogen.

The spectrum of the hydrogen atom has played a central part in fundamental physics over the past 200 years. Historical examples of its importance include the wavelength measurements of absorption lines in the solar spectrum by Fraunhofer, the identification of transition lines by Balmer, Lyman and others, the empirical description of allowed wavelengths by Rydberg, the quantum model of Bohr, the capability of quantum electrodynamics to precisely predict transition frequencies, and modern measurements of the 1S-2S transition by Hänsch to a precision of a few parts in 1015. Recent technological advances have allowed us to focus on antihydrogen-the antimatter equivalent of hydrogen. The Standard Model predicts that there should have been equal amounts of matter and antimatter in the primordial Universe after the Big Bang, but today's Universe is observed to consist almost entirely of ordinary matter. This motivates the study of antimatter, to see if there is a small asymmetry in the laws of physics that govern the two types of matter. In particular, the CPT (charge conjugation, parity reversal and time reversal) theorem, a cornerstone of the Standard Model, requires that hydrogen and antihydrogen have the same spectrum. Here we report the observation of the 1S-2S transition in magnetically trapped atoms of antihydrogen. We determine that the frequency of the transition, which is driven by two photons from a laser at 243 nanometres, is consistent with that expected for hydrogen in the same environment. This laser excitation of a quantum state of an atom of antimatter represents the most precise measurement performed on an anti-atom. Our result is consistent with CPT invariance at a relative precision of about 2 × 10-10.

Observation of the hyperfine spectrum of antihydrogen.

The observation of hyperfine structure in atomic hydrogen by Rabi and co-workers and the measurement of the zero-field ground-state splitting at the level of seven parts in 1013 are important achievements of mid-twentieth-century physics. The work that led to these achievements also provided the first evidence for the anomalous magnetic moment of the electron, inspired Schwinger's relativistic theory of quantum electrodynamics and gave rise to the hydrogen maser, which is a critical component of modern navigation, geo-positioning and very-long-baseline interferometry systems. Research at the Antiproton Decelerator at CERN by the ALPHA collaboration extends these enquiries into the antimatter sector. Recently, tools have been developed that enable studies of the hyperfine structure of antihydrogen-the antimatter counterpart of hydrogen. The goal of such studies is to search for any differences that might exist between this archetypal pair of atoms, and thereby to test the fundamental principles on which quantum field theory is constructed. Magnetic trapping of antihydrogen atoms provides a means of studying them by combining electromagnetic interaction with detection techniques that are unique to antimatter. Here we report the results of a microwave spectroscopy experiment in which we probe the response of antihydrogen over a controlled range of frequencies. The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting. From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 ± 0.5 megahertz, consistent with expectations for atomic hydrogen at the level of four parts in 104. This observation of the detailed behaviour of a quantum transition in an atom of antihydrogen exemplifies tests of fundamental symmetries such as charge-parity-time in antimatter, and the techniques developed here will enable more-precise such tests.

Caregiver skills training for caregivers of individuals with neurodevelopmental disorders: A systematic review and meta-analysis.

AIM: To systematically review the effectiveness of caregiver and parent skills training programs, including caregiver-mediated interventions, for caregivers of individuals with neurodevelopmental disorders. METHOD: We conducted a systematic review with a random-effects meta-analysis. We searched 11 electronic databases through July 2021 and used a snowball methodology to locate relevant articles of randomized controlled trials. Effect size estimates were pooled using Hedges' g from data extracted from study reports and through author requests using random-effects meta-analyses for three child outcome categories (child development, adaptive behavior, and problem behavior) and three caregiver outcome categories (parenting skills and knowledge, psychological well-being, and interpersonal family relations). RESULTS: We located 44 910 records, from which 75 randomized controlled trials involving 4746 individuals with neurodevelopmental disorders and their caregivers were included. Random-effects meta-analyses showed improvements in child development (g = 0.30; 99% confidence interval [CI] = 0.07-0.53) and reduction in reported problem behaviors (g = 0.41; 99% CI = 0.24-0.59), but not a statistically significant improvement in adaptive behavior (g = 0.28; 99% CI = -0.42 to 0.98). Caregivers showed improvements in parenting skills and knowledge (g = 0.72; 99% CI = 0.53-0.90), psychological well-being (g = 0.52; 99% CI = 0.34-0.71), and interpersonal family relations (g = 0.76; 99% CI = 0.32-1.20). INTERPRETATION: Caregiver skills training programs benefit both caregivers and children with neurodevelopmental disorders. Skills training programs improve child development and behavior, improve parenting skills, reduce caregiver mental health issues, and improve family functioning. Programs using culturally appropriate training material to improve the development, functioning, and participation of children within families and communities should be considered when caring for children with neurodevelopmental disorders.

Trajectories of loneliness during COVID-19 pandemic and associations with mental health and substance use.

We examined patterns of longitudinal trajectories of loneliness during the COVID-19 pandemic using six time points (January 2020 [pre-pandemic] to March/April 2021) and whether trajectories were associated with psychological distress (depression/anxiety) and substance use (alcohol/cannabis) outcomes in Spring 2021. Participants were 644 young adults who completed online assessments. Outcomes were regressed on most-likely loneliness trajectory adjusting for pre-pandemic measures. Three loneliness trajectories varied from consistently lower to consistently higher. Pre-pandemic social support was associated with lower odds of a higher loneliness trajectory. Higher loneliness trajectories were associated with greater odds of past-month cannabis use compared to Low trajectories, but not significantly associated with depression, anxiety, or alcohol use in Spring 2021. Interventions addressing co-occurring loneliness and cannabis use are needed.

Substance-Specific Risk Factors for Cannabis and Alcohol Use Among Young Adults Following Implementation of Nonmedical Cannabis Legalization.

Laws regarding cannabis are rapidly changing in the USA as more states legalize nonmedical cannabis for adults aged 21 and older. Previous research has examined whether legalization has led to an increase in cannabis use as well as the use of other substances. The current study examined changes in cannabis- and alcohol-specific risk factors following legalization of nonmedical cannabis. We used 6 years of annual cross-sectional data (2014-2019) from 12,951 young adults age 18 to 25 who resided in Washington state. Risk factors examined include perceiving that use was common among same-age peers, believing use was acceptable, having easy access, and low perceived physical and psychological harm from use. Logistic regression models estimated annual rate of increase in these risk factors. All cannabis-specific risk factors increased among those aged 21+ (range of ORs for annual rate of change: 1.07-1.31) while significant increase in cannabis-related risk factors among those under age 21 was limited to perceptions of cannabis use being common (medical use: OR=1.08, 95% CI: 1.03, 1.12; nonmedical use: OR=1.13, 95% CI: 1.08, 1.18) and low perceived physical harm of occasional use (OR=1.08, 95% CI: 1.03, 1.13). Although descriptive norms for past-year use of alcohol among those aged 21+ increased (OR = 1.09, 95% CI: 1.02, 1.17), other risk factors for alcohol did not change significantly or, in the case of low perceived physical and psychological harm, decreased among both those under age 21 and those aged 21+ (range of ORs = 0.90-0.94). Given these findings show an increase in cannabis-specific risk factors since legalization was implemented, particularly among those young adults aged 21+, preventive interventions correcting risk misperceptions and related risk factors among young adults aged 21+ may prove efficacious in reducing use and resultant negative consequences.

Metacognitive bias resulting from trade-off between local and global motion signals.

Visual confidence generally depends on performance in targeted perceptual tasks. However, it remains unclear how factors unrelated to performance affect confidence. Given the hierarchical nature of visual processing, both local and global stimulus features can influence confidence, but their strengths of influence remain unknown. To address this question, we independently manipulated the local contrast signals and the global coherence signals in a multiple-aperture motion pattern. The drifting-Gabor elements were individually manipulated to give rise to a coherent global motion percept. In both dichotomous direction-discrimination task (Experiment 1) and analog direction-judgment task (Experiment 2), we found stimulus-dependent biases in metacognition despite matched perceptual performance. Specifically, participants systematically gave higher confidence ratings to an incoherent pattern with clear elements (i.e., strong local but weak global signals) than a coherent pattern with noisy elements (i.e., weak local but strong global signals). We did not find any systematic effects of local/global stimulus features on metacognitive sensitivity. Model comparisons show that variation in local/global signals in the stimulus should be considered a factor influencing confidence, even after controlling for the effects of performance. Our results suggest that the metacognitive system, when generating confidence for a perceptual task, puts more weights on local than global signals.

Prospective Associations between Childhood Exposure to Living with Adult Alcohol Misuse and Major Depressive Disorder in Adulthood: The Role of Child Maltreatment.

BACKGROUND: Many children grow up with adult alcohol misuse in the home. A clearer understanding of this exposure's long-term mental health consequences and the role of associated child maltreatment experiences and potential protective factors could guide relevant intervention strategies. OBJECTIVE: To prospectively evaluate the association between living with adult alcohol misuse during childhood and major depressive disorder (MDD) during adulthood; whether child maltreatment explains the association; and whether sex, school bonding, or neighborhood bonding moderate the association.Participants and setting: This study used longitudinal data from 783 individuals followed from childhood to age 39. METHODS: At grade 9, participants were asked whether they lived with adults who misused alcohol. Diagnostic assessments of MDD were conducted across three time-points during participants' thirties and participants were categorized as having met diagnostic criteria 0, 1, or 2 or more times. RESULTS: Ordinal logistic regressions found that children living with adult alcohol misuse showed greater chronicity of adult MDD (OR = 1.63; 95% CI: 1.05, 2.52). There was a 49% reduction in the odds ratio and the association was no longer statistically significant when child maltreatment was included in the model (OR = 1.32; 95% CI: 0.84, 2.07). No statistically significant moderation of associations was observed. CONCLUSIONS: Children exposed to adult alcohol misuse, and maltreatment often associated with this misuse, may be at risk for mental health challenges well into adulthood. Interventions that address childhood exposure to adult alcohol misuse and associated maltreatment may be important to mitigate long-term mental health challenges to exposed children.

Recommendations for quantifying and reducing uncertainty in climate projections of species distributions.

Projecting the future distributions of commercially and ecologically important species has become a critical approach for ecosystem managers to strategically anticipate change, but large uncertainties in projections limit climate adaptation planning. Although distribution projections are primarily used to understand the scope of potential change-rather than accurately predict specific outcomes-it is nonetheless essential to understand where and why projections can give implausible results and to identify which processes contribute to uncertainty. Here, we use a series of simulated species distributions, an ensemble of 252 species distribution models, and an ensemble of three regional ocean climate projections, to isolate the influences of uncertainty from earth system model spread and from ecological modeling. The simulations encompass marine species with different functional traits and ecological preferences to more broadly address resource manager and fishery stakeholder needs, and provide a simulated true state with which to evaluate projections. We present our results relative to the degree of environmental extrapolation from historical conditions, which helps facilitate interpretation by ecological modelers working in diverse systems. We found uncertainty associated with species distribution models can exceed uncertainty generated from diverging earth system models (up to 70% of total uncertainty by 2100), and that this result was consistent across species traits. Species distribution model uncertainty increased through time and was primarily related to the degree to which models extrapolated into novel environmental conditions but moderated by how well models captured the underlying dynamics driving species distributions. The predictive power of simulated species distribution models remained relatively high in the first 30 years of projections, in alignment with the time period in which stakeholders make strategic decisions based on climate information. By understanding sources of uncertainty, and how they change at different forecast horizons, we provide recommendations for projecting species distribution models under global climate change.

Cannabis Use Among Young Adults in Washington State After Legalization of Nonmedical Cannabis.

Objectives. To examine changes in prevalence of cannabis use and of cannabis use disorder symptomatology among young adults from 2014 to 2019 in Washington State, where nonmedical (or "recreational") cannabis was legalized in 2012 and retail stores opened in July 2014. Methods. We used 6 years of cross-sectional data collected annually from 2014 (premarket opening) to 2019 from 12 963 (∼2000 per year) young adults aged 18 to 25 years residing in Washington. Logistic regression models estimated yearly change in prevalence of cannabis use at different margins and related outcomes. Results. Prevalence of past-year, at least monthly, at least weekly, and daily use of cannabis increased for young adults, although increases were driven by changes among those aged 21 to 25 years. There was also a statistically significant increase in prevalence of endorsing at least 2 of 5 possible symptoms associated with cannabis use disorder. Conclusions. Among young adults in Washington, particularly those of legal age, prevalences of cannabis use and cannabis use disorder symptomatology have increased since legalization. This trend may require continued monitoring as the nonmedical cannabis market continues to evolve. (Am J Public Health. 2022;112(4):638-645. https://doi.org/10.2105/AJPH.2021.306641).

Associations of Cumulative and Point-in-Time Neighborhood Poverty and Walkability with Body Mass from Age 30 to 39.

Few studies examining the effects of neighborhood exposures have accounted for longitudinal residential history. This study examined associations of body mass index (BMI, kg/m2) with neighborhood-level walkability and poverty, both assessed concurrently and cumulatively in the years leading up to BMI assessment. Participants (N = 808) were from a cohort study of individuals originally recruited from public schools in Seattle, Washington, in fifth grade in 1985. Height and weight for BMI were obtained at four assessments at ages: 30 (in 2005), 33, 35, and 39. Participants also completed residential timelines listing each address where they lived from ages 28 to 39, creating a continuous record of addresses and moves. Neighborhood-level walkability and poverty were based on census block groups of each address. Generalized estimating equation models estimated associations of standardized neighborhood variables, both at point-in-time concurrently with assessment of BMI and cumulatively up to the time of BMI assessment. Mean BMI across observations was 28.8 (SD = 7.1). After adjusting for covariates, cumulative walkability was associated with lower BMI (b = - 0.28; 95% CI: - 0.55, - 0.02), and cumulative neighborhood poverty was associated with higher BMI (b = 0.35; 95% CI: 0.09, 0.60). When examining point-in-time concurrent walkability and poverty with BMI, adjusted associations were close to the null and non-significant. This study provides evidence for a significant role of cumulative exposure to neighborhood built and socioeconomic environments predicting BMI. It underscores the relative strength and importance of cumulative assessments to capture neighborhood exposure not captured through point-in-time assessments.