Category: Statistics

Chaos. 2024 Apr 1;34(4):043129. doi: 10.1063/5.0200335.

ABSTRACT

In this paper, the dynamical properties of soliton interactions in the focusing Gardner equation are analyzed by the conventional two-soliton solution and its degenerate cases. Using the asymptotic expressions of interacting solitons, it is shown that the soliton polarities depend on the signs of phase parameters, and that the degenerate solitons in the mixed and rational forms have variable velocities with the time dependence of attenuation. By means of extreme value analysis, the interaction points in different interaction scenarios are presented with exact determination of positions and occurrence times of high transient waves generated in the bipolar soliton interactions. Next, with all types of two-soliton interaction scenarios considered, the interactions of two solitons with different polarities are quantitatively shown to have a greater contribution to the skewness and kurtosis than those with the same polarity. Specifically, the ratios of spectral parameters (or soliton amplitudes) are determined when the bipolar soliton interactions have the strongest effects on the skewness and kurtosis. In addition, numerical simulations are conducted to examine the properties of multi-soliton interactions and their influence on higher statistical moments, especially confirming the emergence of the soliton interactions described by the mixed and rational solutions in a denser soliton ensemble.

PMID:38598677 | DOI:10.1063/5.0200335

Chaos. 2024 Apr 1;34(4):043130. doi: 10.1063/5.0200029.

ABSTRACT

Developing reliable methodologies to decode brain state information from electroencephalogram (EEG) signals is an open challenge, crucial to implementing EEG-based brain-computer interfaces (BCIs). For example, signal processing methods that identify brain states could allow motor-impaired patients to communicate via non-invasive, EEG-based BCIs. In this work, we focus on the problem of distinguishing between the states of eyes closed (EC) and eyes open (EO), employing quantities based on permutation entropy (PE). An advantage of PE analysis is that it uses symbols (ordinal patterns) defined by the ordering of the data points (disregarding the actual values), hence providing robustness to noise and outliers due to motion artifacts. However, we show that for the analysis of multichannel EEG recordings, the performance of PE in discriminating the EO and EC states depends on the symbols’ definition and how their probabilities are estimated. Here, we study the performance of PE-based features for EC/EO state classification in a dataset of N=107 subjects with one-minute 64-channel EEG recordings in each state. We analyze features obtained from patterns encoding temporal or spatial information, and we compare different approaches to estimate their probabilities (by averaging over time, over channels, or by “pooling”). We find that some PE-based features provide about 75% classification accuracy, comparable to the performance of features extracted with other statistical analysis techniques. Our work highlights the limitations of PE methods in distinguishing the eyes’ state, but, at the same time, it points to the possibility that subject-specific training could overcome these limitations.

PMID:38598676 | DOI:10.1063/5.0200029

Med Care. 2024 Apr 10. doi: 10.1097/MLR.0000000000001999. Online ahead of print.

ABSTRACT

BACKGROUND: The provision of high-quality hospital care requires adequate space, buildings, and equipment, although redundant infrastructure could also drive service overprovision.

OBJECTIVE: To explore the distribution of physical hospital resources-that is, capital assets-in the United States; its correlation with indicators of community health and nonhealth factors; and the association between hospital capital density and regional hospital utilization and costs.

RESEARCH DESIGN: We created a dataset of n=1733 US counties by analyzing the 2019 Medicare Cost Reports; 2019 State Inpatient Database Community Inpatient Statistics; 2020-2021 Area Health Resource File; 2016-2020 American Community Survey; 2022 PLACES; and 2019 CDC WONDER. We first calculated aggregate hospital capital assets and investment at the county level. Next, we examined the correlation between community’s medical need (eg, chronic disease prevalence), ability to pay (eg, insurance), and supply factors with 4 metrics of capital availability. Finally, we examined the association between capital assets and hospital utilization/costs, adjusted for confounders.

RESULTS: Counties with older and sicker populations generally had less aggregate hospital capital per capita, per hospital day, and per hospital discharge, while counties with higher income or insurance coverage had more hospital capital. In linear regressions controlling for medical need and ability to pay, capital assets were associated with greater hospital utilization and costs, for example, an additional $1000 in capital assets per capita was associated with 73 additional discharges per 100,000 population (95% CI: 45-102) and $19 in spending per bed day (95% CI: 12-26).

CONCLUSIONS: The level of investment in hospitals is linked to community wealth but not population health needs, and may drive use and costs.

PMID:38598671 | DOI:10.1097/MLR.0000000000001999

Invest Radiol. 2024 Apr 10. doi: 10.1097/RLI.0000000000001074. Online ahead of print.

ABSTRACT

OBJECTIVES: The aim of this study was to qualitatively and quantitatively assess changes in bovine flexor tendons before and after collagen degradation and at different angles in relation to the static B0 field using 3-dimensional ultra-short echo time (UTE) magnetization transfer (MT) imaging within a clinically feasible acquisition time.

MATERIALS AND METHODS: Eight bovine flexor tendons were examined at 3 T magnetic resonance imaging including 3-dimensional UTE MT and UTE T2* research application sequences (acquired within 4:04 and 6:38 minutes, respectively) before and after enzyme-induced degradation. The tendons were divided into 2 groups: group 1 (controls) treated with phosphate-buffered saline and group 2 treated with collagenase I to induce collagen degeneration. Magnetic resonance imaging was repeated at 0, 27, 55, and 90 degrees to the B0 field. To calculate quantitative tissue properties, all tendons were semiautomatically segmented, and changes in quantitative UTE T2* and UTE MT ratios (MTRs) were compared at different angles and between groups. In addition to descriptive statistics, the coefficient of variation was calculated to compare UTE MT and UTE T2* imaging.

RESULTS: Ultra-short echo time MTR showed a significantly lower coefficient of variation compared with UTE T2* values, indicating a more robust imaging method (UTE MTR 9.64%-11.25%, UTE T2* 18.81%-24.06%, P < 0.001). Both methods showed good performance in detecting degenerated tendons using histopathology as reference standard, with UTE MT imaging having a better area under the curve than UTE T2* mapping (0.918 vs 0.865). Falsely high UTE T2* values were detected at the 55 degrees acquisition angle, whereas UTE MTR values were robust, that is, insensitive to the MAE.

CONCLUSIONS: Ultra-short echo time MT imaging is a reliable method for quantifying tendon degeneration that is robust to the MAE and can be acquired in a clinically reasonable time.

PMID:38598670 | DOI:10.1097/RLI.0000000000001074

Acta Paediatr. 2024 Apr 10. doi: 10.1111/apa.17238. Online ahead of print.

ABSTRACT

AIM: Growth reference values about mid-upper arm circumference (MUAC) are vital for assessing children’s nutritional status. However, Pakistan lacks these reference values and growth charts. This study aims to develop these for children aged 6-60 months and compare them with global standards.

METHODS: The data were acquired from the 2018 National Nutrition Survey of Pakistan, which was conducted by the United Nations Children’s Fund (UNICEF) during 2018-2019. The final study cohort comprised 57 285 children, with 51% being boys. Percentile values and charts for MUAC-for-age were developed using generalised additive models for location, scale and shape with the Box-Cox power exponential distribution.

RESULTS: The mean MUAC was 14.21 cm (±2.07 cm) and 14.13 cm (±2.12 cm) for the boys and girls, respectively. At 60 months of age, the P3 and P97 percentiles for girls were slightly higher than those for boys. The median percentiles of Pakistani children were smaller than the World Health Organisation 2007 standards and with international references.

CONCLUSION: We observed disparities in MUAC-for-age growth references among Pakistani children compared to global standards, highlighting regional, age and gender variations. This underscores the need for developing countries like Pakistan to establish their growth references.

PMID:38598643 | DOI:10.1111/apa.17238

Sci Adv. 2024 Apr 12;10(15):eadj0400. doi: 10.1126/sciadv.adj0400. Epub 2024 Apr 10.

ABSTRACT

Despite the recognized gut-brain axis link, natural variations in microbial profiles between patients hinder definition of normal abundance ranges, confounding the impact of dysbiosis on infant neurodevelopment. We infer a digital twin of the infant microbiome, forecasting ecosystem trajectories from a few initial observations. Using 16S ribosomal RNA profiles from 88 preterm infants (398 fecal samples and 32,942 abundance estimates for 91 microbial classes), the model (Q-net) predicts abundance dynamics with R² = 0.69. Contrasting the fit to Q-nets of typical versus suboptimal development, we can reliably estimate individual deficit risk (M_δ) and identify infants achieving poor future head circumference growth with ≈76% area under the receiver operator characteristic curve, 95% ± 1.8% positive predictive value at 98% specificity at 30 weeks postmenstrual age. We find that early transplantation might mitigate risk for ≈45.2% of the cohort, with potentially negative effects from incorrect supplementation. Q-nets are generative artificial intelligence models for ecosystem dynamics, with broad potential applications.

PMID:38598636 | DOI:10.1126/sciadv.adj0400

Sci Adv. 2024 Apr 12;10(15):eadg9646. doi: 10.1126/sciadv.adg9646. Epub 2024 Apr 10.

ABSTRACT

The ovarian cycle has a well-established circa-monthly rhythm, but the mechanisms involved in its regularity are unknown. Is the rhythmicity driven by an endogenous clock-like timer or by other internal or external processes? Here, using two large epidemiological datasets (26,912 cycles from 2303 European women and 4786 cycles from 721 North American women), analyzed with time series and circular statistics, we find evidence that the rhythmic characteristics of the menstrual cycle are more likely to be explained by an endogenous clock-like driving mechanism than by any other internal or external process. We also show that the menstrual cycle is weakly but significantly influenced by the 29.5-day lunar cycle and that the phase alignment between the two cycles differs between the European and the North American populations. Given the need to find efficient treatments of subfertility in women, our results should be confirmed in larger populations, and chronobiological approaches to optimize the ovulatory cycle should be evaluated.

PMID:38598621 | DOI:10.1126/sciadv.adg9646

N Engl J Med. 2024 Apr 4;390(13):1163-1175. doi: 10.1056/NEJMoa2313487.

ABSTRACT

BACKGROUND: Trials evaluating the omission of completion axillary-lymph-node dissection in patients with clinically node-negative breast cancer and sentinel-lymph-node metastases have been compromised by limited statistical power, uncertain nodal radiotherapy target volumes, and a scarcity of data on relevant clinical subgroups.

METHODS: We conducted a noninferiority trial in which patients with clinically node-negative primary T1 to T3 breast cancer (tumor size, T1, ≤20 mm; T2, 21 to 50 mm; and T3, >50 mm in the largest dimension) with one or two sentinel-node macrometastases (metastasis size, >2 mm in the largest dimension) were randomly assigned in a 1:1 ratio to completion axillary-lymph-node dissection or its omission (sentinel-node biopsy only). Adjuvant treatment and radiation therapy were used in accordance with national guidelines. The primary end point was overall survival. We report here the per-protocol and modified intention-to-treat analyses of the prespecified secondary end point of recurrence-free survival. To show noninferiority of sentinel-node biopsy only, the upper boundary of the confidence interval for the hazard ratio for recurrence or death had to be below 1.44.

RESULTS: Between January 2015 and December 2021, a total of 2766 patients were enrolled across five countries. The per-protocol population included 2540 patients, of whom 1335 were assigned to undergo sentinel-node biopsy only and 1205 to undergo completion axillary-lymph-node dissection (dissection group). Radiation therapy including nodal target volumes was administered to 1192 of 1326 patients (89.9%) in the sentinel-node biopsy-only group and to 1058 of 1197 (88.4%) in the dissection group. The median follow-up was 46.8 months (range, 1.5 to 94.5). Overall, 191 patients had recurrence or died. The estimated 5-year recurrence-free survival was 89.7% (95% confidence interval [CI], 87.5 to 91.9) in the sentinel-node biopsy-only group and 88.7% (95% CI, 86.3 to 91.1) in the dissection group, with a country-adjusted hazard ratio for recurrence or death of 0.89 (95% CI, 0.66 to 1.19), which was significantly (P<0.001) below the prespecified noninferiority margin.

CONCLUSIONS: The omission of completion axillary-lymph-node dissection was noninferior to the more extensive surgery in patients with clinically node-negative breast cancer who had sentinel-node macrometastases, most of whom received nodal radiation therapy. (Funded by the Swedish Research Council and others; SENOMAC ClinicalTrials.gov number, NCT02240472.).

PMID:38598571 | DOI:10.1056/NEJMoa2313487

PLoS One. 2024 Apr 10;19(4):e0295293. doi: 10.1371/journal.pone.0295293. eCollection 2024.

ABSTRACT

RiSE study aims to evaluate a race-based stress-reduction intervention as an effective strategy to improve coping and decrease stress-related symptoms, inflammatory burden, and modify DNA methylation of stress response-related genes in older AA women. This article will describe genomic analytic methods to be utilized in this longitudinal, randomized clinical trial of older adult AA women in Chicago and NYC that examines the effect of the RiSE intervention on DNAm pre- and post-intervention, and its overall influence on inflammatory burden. Salivary DNAm will be measured at baseline and 6 months following the intervention, using the Oragene-DNA kit. Measures of perceived stress, depressive symptoms, fatigue, sleep, inflammatory burden, and coping strategies will be assessed at 4 time points including at baseline, 4 weeks, 8 weeks, and 6 months. Genomic data analysis will include the use of pre-processed and quality-controlled methylation data expressed as beta (β) values. Association analyses will be performed to detect differentially methylated sites on the targeted candidate genes between the intervention and non-intervention groups using the Δβ (changes in methylation) with adjustment for age, health behaviors, early life adversity, hybridization batch, and top principal components of the probes as covariates. To account for multiple testing, we will use FDR adjustment with a corrected p-value of <0.05 regarded as statistically significant. To assess the relationship between inflammatory burden and Δβ among the study samples, we will repeat association analyses with the inclusion of individual inflammation protein measures. ANCOVA will be used because it is more statistically powerful to detect differences.

PMID:38598554 | DOI:10.1371/journal.pone.0295293

PLoS One. 2024 Apr 10;19(4):e0297941. doi: 10.1371/journal.pone.0297941. eCollection 2024.

ABSTRACT

BACKGROUND AND AIM: Stroke is a serious threat to human life and health, and post-stroke insomnia is one of the common complications severely impairing patients’ quality of life and delaying recovery. Early understanding of the relationship between stroke and post-stroke insomnia can provide clinical evidence for preventing and treating post-stroke insomnia. This study was to investigate the prevalence of insomnia in patients with stroke.

METHODS: The Web of Science, PubMed, Embase, and Cochrane Library databases were used to obtain the eligible studies until June 2023. The quality assessment was performed to extract valid data for meta-analysis. The prevalence rates were used a random-efect. I2 statistics were used to assess the heterogeneity of the studies.

RESULTS: Twenty-six studies met the inclusion criteria for meta-analysis, with 1,193,659 participants, of which 497,124 were patients with stroke.The meta-analysis indicated that 150,181 patients with stroke developed insomnia during follow-up [46.98%, 95% confidence interval (CI): 36.91-57.18] and 1806 patients with ischemic stroke (IS) or transient ischemic attack (TIA) developed insomnia (47.21%, 95% CI: 34.26-60.36). Notably, 41.51% of patients with the prevalence of nonclassified stroke developed insomnia (95% CI: 28.86-54.75). The incidence of insomnia was significantly higher in patients with acute strokes than in patients with nonacute strokes (59.16% vs 44.07%, P < 0.0001).Similarly, the incidence of insomnia was significantly higher in the patients with stroke at a mean age of ≥65 than patients with stroke at a mean age of <65 years (47.18% vs 40.50%, P < 0.05). Fifteen studies reported the follow-up time. The incidence of insomnia was significantly higher in the follow-up for ≥3 years than follow-up for <3 years (58.06% vs 43.83%, P < 0.05). Twenty-one studies used the Insomnia Assessment Diagnostic Tool, and the rate of insomnia in patients with stroke was 49.31% (95% CI: 38.59-60.06). Five studies used self-reporting, that the rate of insomnia in patients with stroke was 37.58% (95% CI: 13.44-65.63).

CONCLUSIONS: Stroke may be a predisposing factor for insomnia. Insomnia is more likely to occur in acute-phase stroke, and the prevalence of insomnia increases with patient age and follow-up time. Further, the rate of insomnia is higher in patients with stroke who use the Insomnia Assessment Diagnostic Tool.

PMID:38598535 | DOI:10.1371/journal.pone.0297941