Category: Statistics

Chaos. 2026 May 1;36(5):053103. doi: 10.1063/5.0323611.

ABSTRACT

Algebraic representations of time series are symbolic representations whose symbols belong to a finite group. Precisely, the framework of the present paper is the analysis of coupled time series in algebraic representations and, more generally, group-valued time series. The prototype of an algebraic representation is an ordinal representation, whose symbols are permutations, also called ordinal patterns in the context of time series analysis. In fact, permutations, endowed with function composition, build a group called a symmetric group. A simple way to harness the algebraic structure of the alphabet in such cases is the concept of transcript from one group element to another. Since transcripts involve two group elements, they are very suitable for studying couplings between time series in the same algebraic representation. In this paper, we outline several existing entropic and algebraic transcript-based tools for analyzing coupled time series and systems. In addition to entropy, the entropic tools include divergence, statistical complexity, and mutual information. The algebraic tools comprise order classes and, most recently, the Cayley and Kendall distances. We use the detection of generalized synchronization in a well-studied coupled system to compare the performances of some of those tools. To this end, we also provide an alternative tool called the similarity distance between time series, which is a mean Kendall distance. We found that the novel similarity distance outperforms the other tools tested.

PMID:42065907 | DOI:10.1063/5.0323611

JAMA Netw Open. 2026 May 1;9(5):e269335. doi: 10.1001/jamanetworkopen.2026.9335.

ABSTRACT

IMPORTANCE: Housing insecurity is a key social determinant of health, yet its association with health outcomes among older persons has been understudied.

OBJECTIVE: To examine the associations between housing insecurity and the development of frailty, disability, and dementia, as well as mortality.

DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study was based on data from the National Health and Aging Trends Study (NHATS) from 2015 to 2020. Data analysis was conducted from August 2024 to February 2026. Participants were community-living persons aged 65 years or older in the contiguous US.

EXPOSURES: Three forms of housing insecurity derived from the NHATS annual survey: poor housing affordability, poor housing quality, and poor neighborhood quality.

MAIN OUTCOMES AND MEASURES: The primary outcomes were time to onset of frailty, disability, and dementia, and time to death over 5 years. Geriatric conditions were obtained from the NHATS annual survey, and all-cause mortality from linked Medicare records. Discrete cause-specific hazards models accounting for the competing risk of death (equivalent to multinomial logistic regression) were used to estimate relative risk ratios (RRRs) for geriatric conditions, and time-varying Cox regression models were used to estimate hazard ratios (HRs) for mortality.

RESULTS: Among the 7499 participants (mean [SD] age, 78.2 [7.8] years; 4335 [55.3%] female), after adjustment for age, sex, race and ethnicity, education, Medicaid eligibility, household income, smoking status, and comorbidity, poor housing affordability was significantly associated with higher risks of frailty (RRR, 1.23; 95% CI, 1.01-1.49), disability (RRR, 1.24; 95% CI, 1.01-1.54), dementia (RRR, 1.37; 95% CI, 1.11-1.69), and mortality (HR, 1.51; 95% CI, 1.34-1.70). Similarly, poor housing quality was significantly associated with higher risks of frailty (RRR, 1.30; 95% CI, 1.04-1.62), disability (RRR, 1.33; 95% CI, 1.13-1.57), and mortality (HR, 1.15; 95% CI, 1.01-1.32), but not dementia (RRR, 1.16; 95% CI, 0.90-1.49). Poor neighborhood quality was not associated with any outcome in the adjusted analyses. The adjusted risk differences ranged from 1.9 percentage points (95% CI, 0.2-3.1 percentage points) for housing quality with mortality to 11.1 percentage points (95% CI, 7.9-14.3 percentage points) for housing affordability with disability.

CONCLUSIONS AND RELEVANCE: In this cohort study of community-living older US persons, poor housing affordability was associated with higher risks of frailty, disability, dementia, and mortality, and poor housing quality was associated with higher risks of frailty, disability, and mortality. These findings highlight housing insecurity as a clinically relevant social determinant of health among older persons.

PMID:42065888 | DOI:10.1001/jamanetworkopen.2026.9335

JAMA Netw Open. 2026 May 1;9(5):e269842. doi: 10.1001/jamanetworkopen.2026.9842.

ABSTRACT

IMPORTANCE: Simultaneous cannabis and alcohol use (co-use) is a public safety concern. Controlled data on the effects of co-ingestion of oral cannabis products (edibles) with alcohol are lacking, despite an increased prevalence of this behavior.

OBJECTIVE: To evaluate the individual and interactive effects of cannabis edibles and alcohol on simulated driving and subjective and objective impairment measures.

DESIGN, SETTING, AND PARTICIPANTS: This within-participant, double-blind, double-dummy crossover study of healthy adults included 7 outpatient sessions, separated by 1 week, at Johns Hopkins University School of Medicine from February 2022 to August 2025.

INTERVENTION: Brownies containing 0 mg, 10 mg, or 25 mg Δ9-tetrahydrocannabinol (THC) combined with placebo drinks or alcohol-containing drinks, calculated to achieve breath alcohol concentrations (BrACs) of 0%, 0.05%, or 0.08%.

MAIN OUTCOMES AND MEASURES: Driving outcomes included the global drive score (GDS), a composite index of multiple driving measures, and the standard deviation of lateral position as the main outcomes. Other outcomes included cumulative impairment clues on standardized field sobriety tests (SFSTs), subjective drug effects, cognitive and psychomotor performance (using the DRUID [Driving Under the Influence of Drugs] application), and blood cannabinoid concentrations.

RESULTS: Participants included 25 healthy adults (15 males [60%]; mean [SD] age, 25.6 [4.9] years) who reported recent binge drinking, prior cannabis and alcohol co-use, and fewer than 3 cannabis uses per week. Compared with placebo, all active drug conditions except 10 mg THC negatively impacted driving performance (ie, GDS). Driving impairment from alcohol alone at 0.08% BrAC was comparable with that of 0.05% BrAC and 10 mg THC (mean [SD] GDS, 1.6 [1.6] vs 1.6 [1.4]) and significantly lower than 0.05% BrAC and 25 mg THC (mean [SD] GDS, 2.5 [1.7]; P = .02). Driving impairment and subjective intoxication (eg, confidence to drive) were often greater under co-use conditions compared with cannabis or alcohol alone. Relative to placebo, SFST performance worsened at 0.08% BrAC (mean [SD] score, 2.2 [2.2] vs 0.2 [1.3]; P = .008) but not in several other conditions in which marked driving decrements were observed. THC and metabolite pharmacokinetics were not influenced by alcohol.

CONCLUSIONS AND RELEVANCE: In this crossover trial of healthy adults who co-used cannabis and alcohol, cannabis edibles combined with alcohol augmented driving impairment. The legal alcohol intoxication limit in most of the US (0.08% BrAC) may be too liberal if a driver has co-used cannabis and alcohol. In this era of expanding cannabis legalization, there is a pressing public health need for improved impairment detection strategies and consideration of cannabis and alcohol co-use in policies dictating access to these substances.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04931095.

PMID:42065887 | DOI:10.1001/jamanetworkopen.2026.9842

JAMA Netw Open. 2026 May 1;9(5):e2610045. doi: 10.1001/jamanetworkopen.2026.10045.

ABSTRACT

IMPORTANCE: Sickle cell disease (SCD) disproportionately affects racial and ethnic minority groups in the US and is associated with high levels of morbidity and health care utilization. However, population-level geographic differences and temporal variation in SCD hospitalization outcomes remain incompletely characterized.

OBJECTIVE: To assess temporal and regional patterns of SCD hospitalizations in New York State from 2009 through 2022.

DESIGN, SETTING, AND PARTICIPANTS: This retrospective cross-sectional study analyzed inpatient SCD hospitalizations recorded in the New York State Statewide Planning and Research Cooperative System deidentified database between January 1, 2009, and December 31, 2022. The analytic sample included 42 271 hospitalizations after exclusion of records with missing demographic, cost, or facility information. Data analysis was conducted from July 17, 2024, to February 14, 2025.

EXPOSURES: Hospitalization with SCD across 8 state-defined health service areas.

MAIN OUTCOMES AND MEASURES: Outcomes included regional distribution of hospitalizations, mean length of stay, mean total charges, and trends in severity of illness and risk of mortality as defined by the All Patient Refined Diagnosis Related Groups classification system. Demographic and regional distributions were compared across years and regions.

RESULTS: Among 42 271 SCD hospitalizations (21 777 female [51.5%]), most occurred among individuals identified as Black (35 318 [83.6%) compared with White (750 [1.8%]), multiracial (242 [0.6%]), and other race or ethnicity 5956 (14.1%) and were aged 18 to 29 (16 794 [39.7%]) or 30 to 49 years (13 480 [31.8%]). New York City accounted for the largest proportion of hospitalizations statewide. There were significant differences in the length of stay and total charges across service areas; Central New York had the longest mean (SD) length of stay of 6.3 (7.3) days, followed by the Hudson Valley (6.2 [7.2]) days, while Long Island had the highest mean (SD) total charges at $59 476.3 ($63 823.5). The proportion of hospitalizations classified as major severity increased from 751 of 5897 (12.7%) in 2009 to 1011 of 3709 (27.3%) in 2022, and the proportion classified as major risk of mortality increased from 170 of 5897 (2.9%) to 469 of 3709 (12.6%) during the same period. Long Island had the highest proportion of hospitalizations with major risk of mortality (93 of 970 [9.6%]), whereas New York City exhibited one of the lower proportions of major risk of mortality (1531 of 27 923 [5.5%]) despite high hospitalization volume.

CONCLUSIONS AND RELEVANCE: In this cross-sectional study, geographic and temporal differences in SCD hospitalization outcomes were observed across New York State during a 14-year period. These findings suggest the need for region-specific strategies to improve access to specialized care, reduce severe outcomes, and optimize health care resource use for individuals living with SCD.

PMID:42065886 | DOI:10.1001/jamanetworkopen.2026.10045

JAMA Netw Open. 2026 May 1;9(5):e2610062. doi: 10.1001/jamanetworkopen.2026.10062.

ABSTRACT

IMPORTANCE: Acute respiratory tract infections (ARTIs) are among the most common reasons for pediatric primary care visits and antibiotic receipt. Telemedicine outside of primary care settings has been associated with overuse of antibiotics for ARTIs in children. The quality of telemedicine when integrated within primary care for children is not clear.

OBJECTIVE: To compare antibiotic management during primary care visits conducted through telemedicine vs in-person.

DESIGN, SETTING, AND PARTICIPANTS: This retrospective, cross-sectional study analyzed visits for ARTIs in children younger than 18 years between January 1 and December 31, 2023, at 694 US primary care practices (including community health organizations, independent pediatric practices, and practice networks affiliated with large health systems). Analyses were performed between October 1, 2024, and February 12, 2026.

EXPOSURE: Primary care telemedicine vs primary care in-person index visits.

MAIN OUTCOMES AND MEASURES: The primary outcomes were percentage of index visits with antibiotics prescribed and percentage with antibiotic management concordant with guidelines for visit diagnosis. Secondary outcomes included index visit diagnosis, follow-up visits within 14 days, and antibiotic prescription within 14 days. Weighted analyses were conducted using a propensity score model to estimate the probability of an ARTI index visit being conducted via telemedicine and estimated the average treatment effect associated with telemedicine.

RESULTS: This study included 438 148 in-person and 11 482 telemedicine index ARTI visits at primary care practices by 302 817 children (mean [SD] age: 6.6 [4.7] years; 51.4% male). Antibiotic prescription occurred during 46.8% (95% CI, 45.1%-48.4%) of primary care in-person visits vs 34.6% (95% CI, 27.0%-42.3%) of primary care telemedicine visits in the propensity score-weighted model, with a difference of -12.1 (95% CI, -19.3 to -5.0) percentage points. Antibiotic management was guideline concordant for 86.2% (95% CI, 85.1%-87.3%) of primary care in-person visits vs 85.5% (95% CI, 80.5%-90.4%) of primary care telemedicine visits, with a difference of -0.7 (95% CI, -5.3 to 3.8) percentage points. The proportion of follow-up visits and antibiotic prescription within 14 days after initial visit did not vary significantly by index visit modality.

CONCLUSIONS AND RELEVANCE: In this cross-sectional study of primary care practices caring for children, telemedicine integrated within primary care was associated with judicious antibiotic prescribing without increased follow-up visits or subsequent antibiotics prescribed. Supporting primary care practices in offering telemedicine for acute concerns may be a strategy to limit unnecessary antibiotic receipt.

PMID:42065885 | DOI:10.1001/jamanetworkopen.2026.10062

JAMA Health Forum. 2026 May 1;7(5):e260979. doi: 10.1001/jamahealthforum.2026.0979.

ABSTRACT

IMPORTANCE: Primary care improves population health, yet access is a challenge in the US. It is unclear how primary care use, access, and access disparities have changed since widespread adoption of telemedicine during the pandemic.

OBJECTIVE: To quantify trends in primary care use and determine the role of telemedicine in primary care access and access disparities for traditional Medicare beneficiaries.

DESIGN, SETTING, AND PARTICIPANTS: Serial cross-sectional study using 2017-2023 100% claims and administrative data for traditional Medicare beneficiaries continuously enrolled and alive for the given year. Data were analyzed from October 2024 to July 2025.

MAIN OUTCOMES AND MEASURES: Primary care visits per beneficiary, primary care access (defined as ≥1 virtual or in-person primary care visit in the year), and primary care continuity (Bice-Boxerman Index).

RESULTS: Among 258 324 127 person-years from 2017 to 2023, primary care visit rates decreased from 2.54 per person-year in 2017 to 2.27 per person-year in 2023, and access dropped from 61.9% to 59.8%. In 2023, virtual visits comprised 7% of primary care visits and 14% of beneficiaries who accessed primary care used telemedicine to do so. Disparities in access by race, geography, and income increased slightly from 2019 to 2023, and beneficiaries in historically underserved groups by race, geography, and income who accessed primary care were more likely than others to use telemedicine to do so. Primary care continuity decreased from 0.72 in 2019 to 0.65 in 2023; in 2023, continuity was slightly higher for those using telemedicine for primary care than for those who were not.

CONCLUSIONS AND RELEVANCE: This serial cross-sectional study found that across all traditional Medicare beneficiaries, primary care visit rates and access decreased, with virtual visits comprising a small share of previously in-person visits. Access disparities widened while those in underserved groups were more likely than others to use telemedicine for this access. Results suggest that telemedicine plays a small but potentially important role in primary care access.

PMID:42065879 | DOI:10.1001/jamahealthforum.2026.0979

J Phys Chem A. 2026 May 1. doi: 10.1021/acs.jpca.6c01093. Online ahead of print.

ABSTRACT

The fluorinated Criegee intermediate, FCHOO, is produced from the ozonolysis of hydrofluoroolefins (HFOs) which are next-generation refrigerants. Unimolecular decay of syn-FCHOO proceeds via a 1,3 ring closure pathway to fluorodioxirane and subsequent rearrangement and/or dissociation to many products including hydroxyl (OH) radicals that are detected experimentally. Vibrational activation of jet-cooled syn-FCHOO with two quanta of CH stretch (17.70 kcal mol^-1) leads to unimolecular decay via quantum mechanical tunneling at an energy slightly below the transition state barrier of 18.03 ± 0.25 kcal mol^-1, determined utilizing the high accuracy composite HEAT-345(Q)_Λ method. The observed unimolecular decay rate of (5.4 ± 1.6) × 10⁷ s^-1 is an order of magnitude slower than that predicted by statistical unimolecular reaction theory with quantum mechanical tunneling. The nonstatistical behavior originates from excitation of a CH stretch vibration that is orthogonal to the heavy atom motions along the reaction coordinate and slow intramolecular vibrational energy redistribution due to the sparse density of states.

PMID:42065861 | DOI:10.1021/acs.jpca.6c01093

J Epidemiol Glob Health. 2026 May 1. doi: 10.1007/s44197-026-00570-7. Online ahead of print.

ABSTRACT

BACKGROUND: The long-term effects of Percutaneous Endoscopic Gastrostomy (PEG) versus Nasogastric Tube (NG) placement on adult mortality and aspiration pneumonia are debated. This study aimed to compare these long-term risks using a large, multi-institutional retrospective database.

METHODS: This retrospective cohort study used de-identified data from the TriNetX US Collaborative Network (2005-2024). Adults undergoing PEG or NG tube placement were propensity score-matched (1:1), although swallowing study results were unavailable for matching. Primary outcomes over a 10-year follow-up were incident aspiration pneumonia and all-cause mortality. Analyses included Cox proportional hazards models, landmark analyses, and stratified analyses by NG tube placement frequency.

RESULTS: Among 34,539 matched pairs, PEG was associated with lower observed 30-day all-cause mortality (HR 0.53, 95% CI 0.51-0.56) but higher mortality during 31-365 days (HR 1.70, 1.59-1.81) and 1-10 years (HR 1.57, 1.49-1.65). In the overall matched cohort, PEG was associated with a higher long-term aspiration pneumonia risk (HR 1.66, 1.56-1.75). When stratified by NG tube placement frequency, the between-group mortality difference attenuated from HR 1.16 (1.12-1.19) at one placement to HR 0.74 (0.65-0.86) at ≥ 5 placements. The aspiration pneumonia association attenuated but remained statistically significant across all strata.

CONCLUSION: PEG was associated with a higher overall observed risk of aspiration pneumonia; however, this association attenuated with increasing NG tube placement frequency, and the observed mortality difference was no longer statistically significant among patients with repeated NG tube placements. These observational associations may reflect differences in NG tube placement frequency and clinical context within the comparator group, and may offer a clinical reference for tube access selection in similar patients.

PMID:42065858 | DOI:10.1007/s44197-026-00570-7

Community Ment Health J. 2026 May 1. doi: 10.1007/s10597-026-01650-5. Online ahead of print.

ABSTRACT

Psychological interventions are recommended for people under Crisis Resolution Home Treatment Teams (CRHTTs). Non-registered psychology roles (Assistant Psychologists (APs) and Trainee Associate Psychological Practitioners (TAPPs)) are potentially both cost and clinically effective for delivering brief interventions in CRHTTs. This study aimed to quantitatively examine routine outcome change associated with two brief, skills-based interventions (the Crisis Toolbox (CTB) and the Emotion Coping Skills (ECS)) delivered by APs and TAPPs in one CRHTT. A retrospective service evaluation of 490 service users who accessed either the CTB or ECS between June 2020 and February 2025 was employed. The Clinical Outcomes in Routine Evaluation – 10 (Core-10) and Mental Health Confidence Scale (MHCS) measures were completed pre- and post- intervention. Paired samples t-tests were conducted and demographics (age, gender, and ethnicity) collected. There was a statistically significant effect in improving scores on both measures at the post-intervention timepoint (CORE-10: 8.636, 95% CI [7.810 to 9.461], t(297) = 20.586, p < .001; MHCS: -13.537, 95% CI [-14.827 to -12.237], t{293) = -20.568, p < .001). This significant effect remained when looking at males and females separately. Asian and Black ethnic groups were underrepresented in the sample compared to local demographics, whilst other ethnic groups showed similar representation. Findings suggest that CTB and ECS may be clinically effective in reducing distress and increasing confidence in coping with mental health challenges for service users. Additionally, this evaluation has highlighted the need for better understanding UK ethnic minority representation in CRHTTs and consideration of possible barriers to access.

PMID:42065842 | DOI:10.1007/s10597-026-01650-5