Tag: pubmed

Phys Rev Lett. 2026 Apr 17;136(15):158401. doi: 10.1103/g6l8-wbt1.

ABSTRACT

Biological tissues are active materials whose nonequilibrium dynamics emerge from distinct cellular force-generating mechanisms. Using a two-dimensional active foam model, we compare the effects of traction forces and junctional tension fluctuations on confluent tissue dynamics. While these two modes of activity produce qualitatively different cell shapes, rearrangement statistics, and spatiotemporal correlations in fluid states, we find that the long-time cellular motion universally converges to persistent Brownian dynamics. This universal feature contrasts with the nonuniversal correlations between cell geometry, rearrangement rate, and fluidity, which depend sensitively on the underlying modes of active force. Our results demonstrate that persistent Brownian motion provides a minimal framework for describing tissue dynamics, while distinct active forces leave identifiable structural and dynamical signatures, thereby enabling inference of the dominant active force in fluid state tissues.

PMID:42066318 | DOI:10.1103/g6l8-wbt1

Phys Rev Lett. 2026 Apr 17;136(15):151602. doi: 10.1103/fsdt-d3p9.

ABSTRACT

Holographic complexity, as the bulk dual of quantum complexity, encodes the geometric structure of black hole interiors. Motivated by the complexity = anything proposal, we introduce the spectral representation for generating functions associated with codimension-one and codimension-zero holographic complexity measures. These generating functions exhibit a universal slope-ramp-plateau structure analogous to the spectral form factor in chaotic quantum systems. In such systems, quantum complexity evolves universally, displaying long-time linear growth followed by saturation at late times. By employing the generating function formalism, we show that this universal behavior has two origins: a particular pole structure of the matrix elements of the generating functions in the energy eigenbasis and random matrix universality in spectral statistics. Using the residue theorem, we prove that the existence of this pole structure is a necessary and sufficient condition for the linear growth of holographic complexity measures. Furthermore, we show that the late-time saturation plateau arises directly from the spectral level repulsion, a hallmark of quantum chaos.

PMID:42066312 | DOI:10.1103/fsdt-d3p9

Phys Rev Lett. 2026 Apr 17;136(15):150401. doi: 10.1103/y9z4-v641.

ABSTRACT

We prove that the time required for sustained information scrambling in any Hamiltonian quantum system is universally at least logarithmic in the entanglement entropy of scrambled states. This addresses two foundational problems in nonequilibrium quantum dynamics. (1) It sets the earliest possible time for the applicability of equilibrium statistical mechanics in a quantum system coupled to a bath at a finite temperature. (2) It proves a version of the fast scrambling conjecture, originally motivated in models associated with black holes, as a fundamental property of quantum mechanics itself. Our result builds on a refinement of the energy-time uncertainty principle in terms of the infinite temperature spectral form factor in quantum chaos. We generalize this formulation to arbitrary initial states of the bath, including finite temperature states, by mapping Hamiltonian dynamics with any initial state to nonunitary dynamics at infinite temperature. A regularized spectral form factor emerges naturally from this procedure, whose decay is universally constrained by analyticity in complex time. This establishes an exact speed limit on information scrambling by the most general quantum mechanical Hamiltonian without any restrictions on locality or the nature of interactions.

PMID:42066310 | DOI:10.1103/y9z4-v641

Phys Rev Lett. 2026 Apr 17;136(15):151002. doi: 10.1103/rk8v-rcm3.

ABSTRACT

The mean pairwise velocity of massive halos reflects the gravitational force law on cosmic scales. We combine cosmic microwave background intensity maps from the Atacama Cosmology Telescope and a galaxy catalog from the Sloan Digital Sky Survey to estimate the mean pairwise velocity using the kinematic Sunyaev-Zeldovich (kSZ) effect. On scales from 30 to 230 megaparsecs, we constrain the gravitational acceleration between pairs of halos at separation r to be g∝1/r^{n} with n=2.1±0.3, which is consistent with Newtonian gravity in an expanding spacetime (i.e., the standard ΛCDM model). This constraint shows agreement with an inverse quadratic radial dependence over the large distances separating galaxy halos, as expected in standard cosmology. Upcoming surveys have the potential to rule out n=1 at 10σ significance. Our results establish the kSZ effect as a powerful tool for testing gravity on cosmological scales.

PMID:42066306 | DOI:10.1103/rk8v-rcm3

Phys Rev Lett. 2026 Apr 17;136(15):150403. doi: 10.1103/n2gp-8bx9.

ABSTRACT

We derive detailed and intergral fluctuation relations as well as a thermodynamic uncertainty relation constraining the exchange statistics of an arbitrary number of noncommuting conserved quantities among two quantum systems in transport setups arbitrary far from equilibrium. These universal relations, valid without the need of any efficacy parameter, extend the well-known heat exchange fluctuation theorems for energy and particle transport to the case of non-Abelian quantum transport, where the noncommutativity of the charges allows going beyond standard thermodynamic behavior. In particular, we show that this can lead to enhanced precision in the current fluctuations, and it allows for the inversion of all currents against their affinity biases.

PMID:42066302 | DOI:10.1103/n2gp-8bx9

JMIR Form Res. 2026 May 1;10:e89248. doi: 10.2196/89248.

ABSTRACT

BACKGROUND: The transition from adolescence to adulthood (18 to 25 years) is associated with an increased risk of suicidal ideation and behaviors. Suicide-focused cognitive behavioral therapies (CBTs) have been shown to significantly reduce suicidal ideation and behaviors but are not widely available to high-risk individuals. Digital therapeutics could improve access to these treatments.

OBJECTIVE: This study aimed to evaluate the acceptability, safety, and potential efficacy of OTX-202 among transition-age youth (18 to 25 years) receiving mental health care outside an inpatient hospital setting.

METHODS: In this phase 1 single-arm clinical trial, 59 transition-age youth with recent suicidal ideation or suicide attempts used OTX-202, a smartphone app designed to deliver suicide-focused CBT, concurrently with usual outpatient mental health care. After baseline, eligible patients completed 12 weekly assessments of suicidal ideation, depression, and anxiety.

RESULTS: From baseline to week 12, participants reported statistically significant, large reductions in suicidal ideation (mean difference -5.1, 95% CI -6.5 to -3.7; d=0.95). In total, 3 (5.1%; 95% CI 0%-11.2%) participants reported suicide attempts. Reductions in suicidal ideation and suicide attempt rates were consistent with results from previously published randomized clinical trials of suicide-focused CBTs. Participants rated OTX-202 in the 97th percentile of usability and completed a mean of 9.0 (SD 3.5) of 12 app modules, supporting the app’s acceptability. There were no patient deaths, device-related events, or severe adverse events, supporting the app’s safety.

CONCLUSIONS: Results support the safety, acceptability, and potential efficacy of OTX-202 for reducing suicide risk among transition-age youth.

TRIAL REGISTRATION: ClinicalTrials.gov NCT06008132; https://clinicaltrials.gov/study/NCT06008132.

PMID:42066292 | DOI:10.2196/89248

J Med Internet Res. 2026 May 1;28:e88766. doi: 10.2196/88766.

ABSTRACT

BACKGROUND: Generative artificial intelligence (GenAI) tools are increasingly used in scientific research to support literature searches, evidence synthesis, and manuscript preparation. While these systems promise substantial efficiency gains, concerns have emerged regarding their reliability, particularly their tendency to cite inaccurate, fabricated, or retracted literature. The unrecognized inclusion of retracted studies poses a serious risk to research integrity and evidence-based decision-making. Whether commonly used GenAI tools can reliably detect, exclude, or transparently communicate the retraction status of scientific publications remains unclear.

OBJECTIVE: This study aimed to evaluate the ability of freely available GenAI tools to correctly handle retracted scientific articles during literature searches. Primary and secondary outcomes focused on accuracy, reliability, and consistency in recognizing retracted literature.

METHODS: In this pragmatic trial, nine widely used free-access GenAI tools (ChatGPT 4, ChatGPT 5, Claude, Gemini, Perplexity, Microsoft Copilot, SciSpace, ScienceOS, and Consensus) were evaluated. Each tool was asked five predefined, standardized questions addressing topic overview, article identification, article summarization, and explicit assessment of retraction status. Overall, 15 retracted articles (the 10 most cited and 5 most recently retracted as of May 23, 2025) were selected from the Retraction Watch database. All questions were repeated twice to assess intratool consistency. Responses were independently rated as correct or incorrect by 2 researchers. Descriptive statistics summarized performance, and comparisons between general-purpose and research-focused AI tools were conducted using descriptive statistics. Interreviewer agreement was assessed using Cohen kappa coefficient.

RESULTS: None of the evaluated AI tools consistently handled retracted articles correctly. No model achieved perfect accuracy across all question sets. ChatGPT 5 performed best, defined by the primary outcome of achieving fully correct responses to all five predefined tasks (5/5) for the highest number of retracted articles, correctly answering all five questions for 8 of 15 articles (53.3%). Research-focused tools (SciSpace, ScienceOS, and Consensus) failed to produce a single fully correct response set. Retracted articles were frequently included in topic overviews without warning, with error rates exceeding 40% in several tools. When specifically asked about retraction status, most systems failed to provide correct or complete information. OpenEvidence only reported data for a subset of our retracted articles as it is only used in health care literature. It demonstrated strong performance in topic overviews but low accuracy in identifying retracted articles.

CONCLUSIONS: Freely available GenAI tools are currently not able to detect, exclude, or appropriately flag retracted scientific literature. The widespread and confident reproduction of retracted studies represents a substantial threat to research integrity, particularly in medical and evidence-based fields. Until retraction-aware verification mechanisms are systematically integrated, independent source checking remains essential when using AI-assisted literature tools.

PMID:42066286 | DOI:10.2196/88766

JMIR Med Educ. 2026 May 1;12:e87479. doi: 10.2196/87479.

ABSTRACT

BACKGROUND: Graduate health informatics programs in the United States differ widely in cost, curriculum, and program design. However, it is unclear how these differences influence affordability, accreditation signaling, and preparation for a data-driven workforce.

OBJECTIVE: This study aimed to evaluate the value (tuition and affordability), structure (delivery format, credit load, culminating experience, and accreditation), and curriculum (technology content emphasis) of US graduate health informatics programs. It examined how accreditation and modality relate to program design, and whether tuition-normalized curriculum breadth differed by accreditation status.

METHODS: A cross-sectional study of 107 US graduate health informatics programs was conducted using publicly available data collected between January and May 2025. Tuition was standardized to cost per credit. Curricular content was coded for technology density and mapped to the Commission on Accreditation for Health Informatics and Information Management Education domains. Comparative statistics, regression models, and exploratory cluster analyses were used to assess relationships between tuition, credit requirements, accreditation, delivery format, and curriculum characteristics.

RESULTS: Programs varied by delivery format, with 37 of 107 (34.6%) online, 32 of 107 (29.9%) hybrid, 23 of 107 (21.5%) in person, and 15 of 107 (14.0%) flexible. Credit requirements most commonly fell between 31 and 39 credits. Culminating experiences included capstone (54/107, 50.5%), internships (21/107, 19.6%), and thesis (7/107, 6.5%). Required credit hours showed modest variation by delivery format but not by accreditation status. Accreditation was not associated with differences in the tuition-normalized curriculum breadth structural proxy in this program-level analysis. Programs requiring internships had significantly higher mean credit loads than programs without internships (39.0 vs 31.3 credits; P=.005). Cluster analysis revealed 4 descriptive program configurations differentiated by cost, modality, credit requirements, and culminating experiences.

CONCLUSIONS: In this program-level descriptive analysis, accreditation status was not associated with differences in tuition-normalized curriculum breadth structural proxy. Instead, delivery format and internship requirements were descriptively associated with variation in credit load and cost. Improving transparency in tuition models and aligning program structure with curricular scope may support efforts to enhance equity and value in graduate health informatics education.

PMID:42066252 | DOI:10.2196/87479

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