Tag: statistics

Chaos. 2023 Aug 1;33(8):083131. doi: 10.1063/5.0160868.

ABSTRACT

Inferring the dependence structure of complex networks from the observation of the non-linear dynamics of its components is among the common, yet far from resolved challenges faced when studying real-world complex systems. While a range of methods using the ordinal patterns framework has been proposed to particularly tackle the problem of dependence inference in the presence of non-linearity, they come with important restrictions in the scope of their application. Hereby, we introduce the sign patterns as an extension of the ordinal patterns, arising from a more flexible symbolization which is able to encode longer sequences with lower number of symbols. After transforming time series into sequences of sign patterns, we derive improved estimates for statistical quantities by considering necessary constraints on the probabilities of occurrence of combinations of symbols in a symbolic process with prohibited transitions. We utilize these to design an asymptotic chi-squared test to evaluate dependence between two time series and then apply it to the construction of climate networks, illustrating that the developed method can capture both linear and non-linear dependences, while avoiding bias present in the naive application of the often used Pearson correlation coefficient or mutual information.

PMID:38060778 | DOI:10.1063/5.0160868

Chaos. 2023 Aug 1;33(8):083133. doi: 10.1063/5.0150689.

ABSTRACT

While the acquisition of time series has become more straightforward, developing dynamical models from time series is still a challenging and evolving problem domain. Within the last several years, to address this problem, there has been a merging of machine learning tools with what is called the dynamic-mode decomposition (DMD). This general approach has been shown to be an especially promising avenue for accurate model development. Building on this prior body of work, we develop a deep learning DMD based method, which makes use of the fundamental insight of Takens’ embedding theorem to build an adaptive learning scheme that better approximates higher dimensional and chaotic dynamics. We call this method the Deep Learning Hankel DMD. We likewise explore how our method learns mappings, which tend, after successful training, to significantly change the mutual information between dimensions in the dynamics. This appears to be a key feature in enhancing DMD overall, and it should help provide further insight into developing other deep learning methods for time series analysis and model generation.

PMID:38060776 | DOI:10.1063/5.0150689

Cureus. 2023 Nov 6;15(11):e48378. doi: 10.7759/cureus.48378. eCollection 2023 Nov.

ABSTRACT

Context Cardiovascular diseases (CVDs) are important causes of premature death and disability and elevated healthcare costs. A significant percentage of this morbidity and mortality could be prevented by population-based strategies and cost-effective interventions for those at risk and with established diseases. Aim This study aims to estimate the 10-year risk of cardiovascular events (fatal or non-fatal) among police personnel in Bengaluru City, India. Materials and methods Police personnel above 40 years of age in Bengaluru City, India, were screened for CVD risk using the WHO/International Society of Hypertension (ISH) chart from November 2019 to June 2021. Data was collected by the multistage random sampling method by direct interview at the police station using a semi-structured questionnaire. CVD risk and associated factors were assessed using the WHO/ISH risk prediction chart. Data was entered into Microsoft Office Excel (Microsoft Corporation, Washington, United States) and analyzed using SPSS Statistics version 20.0 (IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.). Results Among 400 study participants, 9.3% (n=37) had a high risk, 2.3% (n=9) had a moderate risk, and 88.5% (n=354) had a low risk of developing fatal or non-fatal cardiovascular events in the next 10 years. Cardiovascular risk was found to be associated with certain socio-demographic and behavioral risk factors. Furthermore, a significant association (p<0.05) was found between CVD risk and the presence of comorbidities such as diabetes and hypertension. Conclusion The study indicates that there is a high burden of predicted cardiovascular risks among the study participants. The WHO/ISH chart can be used as a simple tool for cardiovascular risk stratification.

PMID:38060764 | PMC:PMC10699544 | DOI:10.7759/cureus.48378

Cureus. 2023 Nov 5;15(11):e48320. doi: 10.7759/cureus.48320. eCollection 2023 Nov.

ABSTRACT

Background Screw fixation continues to be a commonly used treatment for syndesmotic disruption; however, screw breakage remains a complication post-fixation. Despite this complication, investigation on the variability of surgical placement in conjunction with syndesmotic screw characteristics affecting breakage has not been fully elucidated. The purpose of this study is to compare patients with syndesmotic screw breakage versus those with intact screws based on surgically controlled variables. Methods A total of 176 patients and 260 syndesmotic screws were included in the study, 88 patients each with and without broken syndesmotic screws. A retrospective analysis of patients who underwent syndesmotic screw fixation was performed. Patients with syndesmotic screw breakage were compared to those with intact screws. Screw width and length, the number of screws used, fracture type, and the number of cortices for fixation were all collected. Further analysis included radiographic measurement of syndesmotic screw angle and height of placement above the tibial plafond. Results Decreased screw width, increased number of screws used, and younger age were all associated with increased rates of screw breakage (p < .001, p = .019, p = 0.020). No statistical difference was appreciated between groups based on screw length, number of cortices used, or angle relative to the tibial plafond (p = .2432, p = .4699, p = .9233). Conclusion Higher placement of syndesmotic screws above the tibiotalar joint, specifically greater than 20 mm above the tibial plafond, increases the screw breakage rate. Decreased screw width, increasing numbers of screws used, and younger age were all also associated with increased rates of screw breakage. No difference was appreciated based on the screw angle relative to the tibial plafond.

PMID:38060758 | PMC:PMC10697833 | DOI:10.7759/cureus.48320

Cureus. 2023 Nov 6;15(11):e48383. doi: 10.7759/cureus.48383. eCollection 2023 Nov.

ABSTRACT

Background This study aims to investigate the relationship between suppressed cortisol levels measured after the 1-mg dexamethasone suppression test (DST) and age based on the hypothesis that aging can alter the activity of the hypothalamic-pituitary-adrenal (HPA) axis. Methodology Data obtained by the retrospective evaluation of suppressed 1-mg overnight DST results of adults aged ≥18 years with adrenal incidentaloma or suspected endogenous hypercortisolemia between December 2021 and March 2023 were subjected to age-dependent correlation analysis. Individuals aged between 18 and 90 years (n = 1111) were classified into the following four groups: <30 years, 30-49 years, 50-69 years, and >70 years. DST results were compared according to age groups. Results Median post-DST cortisol was 18.49 nmol/L, with a level of 17.9 nmol/L in females and 20.7 nmol/L in males. The overall rate of DST suppression was 62.7%, with a rate of 63.8% in females and 59.7% in males. On pairwise comparisons of all age groups, there was a difference in post-DST cortisol levels (p = 0.000). Our statistical analysis revealed a strong positive correlation between age and cortisol levels after DST. Conclusions The negative feedback mechanism for cortisol may be altered in older patients. Therefore, the 1-mg DST may yield a higher rate of false positives in the elderly.

PMID:38060754 | PMC:PMC10699728 | DOI:10.7759/cureus.48383

Cureus. 2023 Nov 6;15(11):e48360. doi: 10.7759/cureus.48360. eCollection 2023 Nov.

ABSTRACT

Introduction Liver cirrhosis is a global health concern with various etiologies, leading to portal hypertension and gastroesophageal varices. Variceal bleeding, a severe complication of cirrhosis, necessitates early detection and intervention to reduce mortality. Endoscopic screening is the gold standard for varices detection but is invasive and expensive. This study evaluates the Lok Score, a non-invasive predictive tool, for identifying esophageal varices in patients with liver cirrhosis. Materials and methods A cross-sectional study involving 150 liver cirrhosis patients was conducted. The Lok score was calculated using specific parameters. Patient data, including age, gender, etiology of liver cirrhosis, Child-Pugh class, varices presence, and grades, were recorded. Statistical analysis was performed using IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp., and diagnostic parameters for Lok Score were computed. Results The study demonstrates that the Lok score exhibits significant potential as a predictive tool for esophageal varices. The mean Lok score significantly differed between individuals with and without varices, suggesting a correlation between Lok score and varices presence. Higher Lok scores may indicate more advanced varices. Utilizing the Lok score in clinical practice could lead to timely interventions, improving patient outcomes. Conclusion The Lok score shows promise as a valuable predictive tool for esophageal varices in liver cirrhosis patients. Early identification using this non-invasive parameter can aid in risk stratification and guide appropriate management strategies. However, further validation and larger studies are needed to fully integrate the Lok score into clinical practice for the benefit of cirrhosis patients.

PMID:38060753 | PMC:PMC10699156 | DOI:10.7759/cureus.48360

JMIR Res Protoc. 2023 Dec 7;12:e46830. doi: 10.2196/46830.

ABSTRACT

BACKGROUND: Treatment-resistant depression (TRD) is the inability of a patient with major depressive disorder (MDD) to accomplish or achieve remission after an adequate trial of antidepressant treatments. Several combinations and augmentation treatment strategies for TRD exist, including the use of repetitive transcranial magnetic stimulation (rTMS), and new therapeutic options are being introduced. Text4Support, a text message-based form of cognitive behavioral therapy that allows patients with MDD to receive daily supportive text messages for correcting or altering negative thought patterns through positive reinforcement, may be a useful augmentation treatment strategy for patients with TRD. It is however currently unknown if adding the Text4Support intervention will enhance the response of patients with TRD to rTMS treatment.

OBJECTIVE: This study aims to assess the initial comparative clinical effectiveness of rTMS with and without the Text4Support program as an innovative patient-centered intervention for the management of patients diagnosed with TRD.

METHODS: This study is a multicenter, prospective, parallel-design, 2-arm, rater-blinded randomized controlled pilot trial. The recruitment process is scheduled to last 12 months. It will involve active treatment for 6 weeks, observation, and a follow-up period of 6 months for participants in the study arms. In total, 200 participants diagnosed with TRD at rTMS care clinics in Edmonton, Alberta, and rTMS clinics in Halifax, Nova Scotia will be randomized to 1 of 2 treatment arms (rTMS sessions alone or rTMS sessions plus Text4Support intervention). Participants in each group will be made to complete evaluation measures at baseline, and 1, 3, and 6 months. The primary outcome measure will be the mean change in the scores of the Patient Health Questionnaire-9 (PHQ-9). The secondary outcome measures will involve the scores of the 7-item Generalized Anxiety Disorders Scale (GAD-7), Columbia-Suicide Severity Rating Scale (CSSRS), and World Health Organization-Five Well-Being Index (WHO-5). Patient data will be analyzed with descriptive statistics, repeated measures, and correlational analyses. Qualitative data will be analyzed using the thematic analysis framework.

RESULTS: The results of the study are expected to be available 18 months from the start of recruitment. We hypothesize that participants enrolled in the rTMS plus Text4Support intervention treatment arm of the study will achieve superior outcomes compared with the outcomes of participants enrolled in the rTMS alone arm.

CONCLUSIONS: The application of the combination of rTMS and Text4Support has not been investigated previously. Therefore, we hope that this study will provide a concrete base of data to evaluate the practical application and efficacy of using the novel combination of these 2 treatment modalities.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/46830.

PMID:38060308 | DOI:10.2196/46830

JMIR Dermatol. 2023 Dec 7;6:e43821. doi: 10.2196/43821.

ABSTRACT

BACKGROUND: Clinical practice guidelines (CPGs) inform evidence-based decision-making in the clinical setting; however, systematic reviews (SRs) that inform these CPGs may vary in terms of reporting and methodological quality, which affects confidence in summary effect estimates.

OBJECTIVE: Our objective was to appraise the methodological and reporting quality of the SRs used in CPGs for cutaneous melanoma and evaluate differences in these outcomes between Cochrane and non-Cochrane reviews.

METHODS: We conducted a cross-sectional analysis by searching PubMed for cutaneous melanoma guidelines published between January 1, 2015, and May 21, 2021. Next, we extracted SRs composing these guidelines and appraised their reporting and methodological rigor using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and AMSTAR (A Measurement Tool to Assess Systematic Reviews) checklists. Lastly, we compared these outcomes between Cochrane and non-Cochrane SRs. All screening and data extraction occurred in a masked, duplicate fashion.

RESULTS: Of the SRs appraised, the mean completion rate was 66.5% (SD 12.29%) for the PRISMA checklist and 44.5% (SD 21.05%) for AMSTAR. The majority of SRs (19/50, 53%) were of critically low methodological quality, with no SRs being appraised as high quality. There was a statistically significant association (P<.001) between AMSTAR and PRISMA checklists. Cochrane SRs had higher PRISMA mean completion rates and higher methodological quality than non-Cochrane SRs.

CONCLUSIONS: SRs supporting CPGs focused on the management of cutaneous melanoma vary in reporting and methodological quality, with the majority of SRs being of low quality. Increasing adherence to PRISMA and AMSTAR checklists will likely increase the quality of SRs, thereby increasing the level of evidence supporting cutaneous melanoma CPGs.

PMID:38060306 | DOI:10.2196/43821

JMIR Form Res. 2023 Dec 7;7:e51812. doi: 10.2196/51812.

ABSTRACT

BACKGROUND: The opioid crisis continues to worsen across the United States, affecting people of all demographics. Few evidence-based interventions exist for educating families, particularly those with adolescents, about opioid prescription safety. Serious games have demonstrated impacts in improving medication-related outcomes for various health conditions. The characterizing goal of this serious game is to improve opioid safety knowledge and awareness among adolescents and their families.

OBJECTIVE: This study evaluated the impact of a serious game, MedSMAR_xT: Adventures in PharmaCity, designed to foster opioid safety awareness among adolescents and their parents.

METHODS: A national sample of parents and their adolescent children was recruited through Qualtrics research panels, social media, listservs, and snowball sampling. Eligible participants were adolescents aged between 12 and 18 years and their parents. Study participants were required to reside in the United States; speak, read, and understand English; and have access to a computer with a webcam. Parent-child dyads completed pregame and postgame surveys and participated in gameplay for up to 30 minutes. Primary outcome scales have been previously evaluated by the study team.

RESULTS: A total of 60 adolescent participants and 68 parent participants met full attention criteria for inclusion in this study. Statistical analysis confirmed that both adolescents’ and parents’ concept scores improved from baseline regarding opioid safety self-efficacy (adolescent: mean 0.35, SD 0.60; P<.001; parent: mean 0.28, SD 0.42; P<.001), perceived knowledge (adolescent: mean 1.08, SD 1.04; P<.001; parent: mean 0.56, SD 0.55; P<.001), behavioral intent (adolescent: mean 0.26, SD 0.39; P<.001; parent: mean 0.25, SD 0.32; P<.001), safe storage (adolescent: mean 0.12, SD 0.27; P<.001; parent: mean 0.03, SD 0.11; P=.03), disposal knowledge (adolescent: mean 0.10, SD 0.27; P=.006; parent: mean 0.07, SD 0.16; P<.001), and knowledge about misuse behavior (adolescent: mean 0.05, SD 0.14; P=.002; parent: mean 0.04, SD 0.10; P<.001). Participant groups, stratified by who completed and who did not complete gameplay, improved their knowledge and awareness, with no significant differences between subgroups.

CONCLUSIONS: The use of this serious game to improve opioid prescription safety practices among parents and adolescents was supported by the study findings. MedSMAR_xT: Adventures in PharmaCity is an intervention with the capability of teaching parents and adolescents about safe opioid prescription practices. Further studies and game refinement are needed to demonstrate the effectiveness of a game-based intervention in clinical settings and community pharmacies.

PMID:38060287 | DOI:10.2196/51812

Bioinformatics. 2023 Dec 7:btad727. doi: 10.1093/bioinformatics/btad727. Online ahead of print.

ABSTRACT

MOTIVATION: Differentiating ecosystems poses a complex, high-dimensional problem constrained by capturing relevant variation across species profiles. Researchers use pairwise distances and subsequent dimensionality reduction to highlight variation in a few dimensions. Despite popularity in analysis of ecological data, these low-dimensional visualizations can contain geometric abnormalities such as “arch” and “horseshoe” effects, potentially obscuring the impact of environmental gradients. These abnormalities appear in ordination but are in fact a product of oversaturated large pairwise distances.

RESULTS: We present Local Manifold distance (LMdist), an unsupervised algorithm which adjusts pairwise beta diversity measures to better represent true ecological distances between samples. Beta diversity measures can have a bounded dynamic range in depicting long environmental gradients with high species turnover. Using a graph structure, LMdist projects pairwise distances onto a manifold and traverses the manifold surface to adjust pairwise distances at the upper end of the beta diversity measure’s dynamic range. This allows for values beyond the range of the original measure. Not all datasets will have oversaturated pairwise distances, nor will capture variation that resembles a manifold, so LMdist adjusts only those pairwise values which may be undervalued in the presence of a sampled gradient. The adjusted distances serve as input for ordination and statistical testing. We demonstrate on real and simulated data that LMdist effectively recovers distances along known gradients and along complex manifolds such as the Swiss roll dataset. LMdist enables more powerful statistical tests for gradient effects and reveals variation orthogonal to the gradient.

AVAILABILITY: Available on GitHub at https://github.com/knights-lab/LMdist.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

PMID:38060267 | DOI:10.1093/bioinformatics/btad727