title: PeerJ
description:  Articles published in PeerJ
link: https://peerj.com/articles/index.rss3?journal=peerj&page=35
creator: info@peerj.com PeerJ
errorsTo: info@peerj.com PeerJ
language: en

title: Quantifying the scale dependence of primary productivity-species-richness relationships
link: https://peerj.com/articles/20297
last-modified: 2025-11-04
description: Vegetation productivity is expected to correlate with species richness, but there is debate about whether the relationship form (non-existent, negative, positive, unimodal) of productivity-species-richness relationships (PSRR) depends on the spatial extent and productivity measure used. Previous assessments employed coarse distance categories to examine scale dependence and did not consider scale dependence for alternative productivity measures. I used spatially varying coefficient models to precisely estimate the distances over which PSRRs change and to map spatial patterns of form for breeding birds across the conterminous United States. I created separate models for three measures summarizing intra-annual estimates of gross primary productivity: sum, minimum, and seasonality (coefficient of variation). Models demonstrated that PSRRs were scale-dependent, and PSRR relationships changed at median distances ranging from 1,010 to 2,184 km depending on the productivity measure. Previously used coarse distance categories would not have resolved the modeled distance estimates. Differences in median distance estimates across productivity measures were not statistically important. Across measures, PSRR form generally alternated between non-existence and positive, but there were pockets where seasonality negatively related to species richness in the western United States. While spatial patterns of form differed across measures, species richness in a small region of the western United States displayed a positive association with all three measures. Spatial patterns were related to prevailing productivity conditions. For example, sum tended to have a positive association with bird species richness in areas characterized by low annual productivity. This study novelly applies spatially varying coefficient models to address the long-debated scale-dependence of PSRR form, and the same approach is broadly applicable across geographies and taxonomic groups.
creator: Brian G. Tavernia
uri: https://doi.org/10.7717/peerj.20297
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Tavernia

title: Cognitive domain-specific impairments and associated risk factors in type 2 diabetes mellitus: a cross-sectional observational study based on neuropsychological assessment from Xiamen, China
link: https://peerj.com/articles/20292
last-modified: 2025-11-04
description: BackgroundType 2 diabetes mellitus (T2DM) is associated with an increased risk of cognitive impairment, yet limited research has been conducted in subtropical regions of China.ObjectiveTo examine the characteristics of cognitive impairment and identify the potential risk factors in patients with T2DM in Xiamen.MethodsThis cross-sectional observational study included 84 patients with T2DM from Zhongshan Hospital Xiamen University. Patients were grouped based on their Montreal Cognitive Assessment (MoCA) scores into a cognitively impaired group (T2DM-CI group, n = 52) and a cognitively normal group (T2DM-NCI group, n = 32). Multivariate logistic regression was used to identify independent risk factors.ResultsAmong the 52 patients in the T2DM-CI group, the most commonly affected cognitive domains were executive function (82.7%), language (75.0%), memory (61.5%), and attention (48.1%), with 59.6% exhibiting impairments in three or more domains. Compared with the T2DM-NCI group, the T2DM-CI group showed poorer performance in most MoCA subdomains—including visuospatial/executive function, language, delayed recall, abstraction, and orientation—as well as in individual cognitive domain tests (all P < 0.05), except for the Clock Drawing Test. Older age (OR = 1.167, 95% CI [1.045–1.303], P = 0.006) and higher lipoprotein (a) levels (OR = 1.109, 95% CI [1.020–1.205], P = 0.015) were independently associated with cognitive impairment in T2DM patients.ConclusionCognitive impairment in T2DM affects multiple domains, with executive dysfunction most prominent. Age and elevated lipoprotein(a) may increase risk. Routine cognitive screening is warranted, particularly in older patients and those with vascular risk factors.
creator: Xueling Xiao
creator: Luling Chen
creator: Jingqi Liu
creator: Jiayan Cai
creator: Manxiang Deng
uri: https://doi.org/10.7717/peerj.20292
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Xiao et al.

title: A machine learning approach to managing game bird introductions
link: https://peerj.com/articles/20291
last-modified: 2025-11-04
description: Effective management of introduced species requires a clear understanding of their habitat requirements. Species distribution models (SDMs) offer a powerful tool for addressing this challenge. We applied seven modeling techniques to predict a suitable habitat for the introduced Chukar Partridge (Alectoris chukar), including artificial neural networks, generalized additive models, k-nearest neighbor, random forests, support vector machines, extreme gradient boosting, and a weighted ensemble approach. Using site-level data on physiography, climate, land cover, and habitat range, we modeled Chukar distributions by simulating historical introduction efforts and extrapolating predictions into surrounding areas to assess cross-regional transferability. Model performance was evaluated using independent, geographically distinct validation datasets. Our results demonstrate that machine learning-based SDMs provide accurate and transferable predictions of Chukar habitat suitability. This study highlights the value of machine learning for predicting establishment success while emphasizing the importance of incorporating species movement behavior and site fidelity into SDM frameworks. Overall, our findings contribute to advancing conservation planning, species reintroductions, and adaptive management strategies.
creator: Austin M. Smith
creator: Wendell P. Cropper, Jr
creator: Michael P. Moulton
uri: https://doi.org/10.7717/peerj.20291
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Smith et al.

title: Control of wind speed and contact angle on submicron particulate matter sampling
link: https://peerj.com/articles/20235
last-modified: 2025-11-04
description: While particulate matter (PM) instruments are widely used for air quality monitoring and policy development, there is limited research on how wind speed (U0) and contact angle (θ) affect the measurement accuracy of submicron PM, or particles with their diameters ≤ one µm (PM1). This study addresses this gap by employing a wind tunnel experiment with a common sampling system featuring a customized thick-walled cylindrical metal inlet. The results reveal that wind-induced aerosol losses can reach up to 9%, and the sampling efficiency has a negative linear relationship with U0 and a third-order polynomial relationship with cos(θ). This model demonstrates a significant discrepancy with classic models in predicting sampling efficiency, which indicates the inapplicability of classic sampling efficiency models to submicron aerosols. The findings of this study can help correct wind-induced errors, improve sampling protocols, and develop new predictive models, which have implications for improving hazardous air quality warning systems and safeguarding public well-being.
creator: Bokun Sun
creator: Ziyang Wang
creator: Jiayun Huang
creator: Yumeng Li
creator: James R. Cooper
creator: Lei Han
creator: Bailiang Li
uri: https://doi.org/10.7717/peerj.20235
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Sun et al.

title: Incidence, persistence, and clearance of cervical human papillomavirus infection among gynecological outpatients in Kunming, Yunnan, China, 2019–2023: a retrospective cohort study
link: https://peerj.com/articles/20215
last-modified: 2025-11-04
description: Human papillomavirus (HPV), a leading sexually transmitted pathogen, is characterized by persistent infection, which represents a critical risk factor for cervical carcinogenesis. This retrospective cohort study investigated the epidemiology of HPV among 45,149 gynecological outpatients in Yunnan, China (2019–2023). The 12-month cumulative incidence of HPV infection was 36.84%, with the highest rates observed in the 30–49-year age group. HPV-52 was the predominant subtype, followed by HPV-51, -81, -58, and -16. Persistent infection was observed in 55.56% of cases, most frequently involving HPV-42, -52, -58, -81, and -56, with higher rates in individuals younger than 30 and older than 59 years. Overall clearance reached 74.43% and was inversely correlated with age. Rapid clearance was predominantly observed for HPV-26, -83, -11, -82, and -44, whereas high-risk HPV types (HPV-58, HPV-52, HPV-35) and low-risk types (HPV-42, HPV-81, HPV-43) exhibited prolonged persistence. Regional data indicate elevated risks of incident and persistent infections with HPV-58, HPV-52, HPV-42, and HPV-81, with older populations showing greater susceptibility to persistence and younger individuals demonstrating faster clearance. These findings underscore the age-specific dynamics of HPV infection and highlight priority subtypes for regional cervical cancer prevention strategies.
creator: Yafei Huang
creator: Xiangcong Wei
creator: Yan Guo
creator: Ting Su
creator: Qiuting Duan
creator: Xin Fan
creator: Jinxiu Wan
creator: Yufan Zhang
creator: Guiqian Zhang
creator: Yi Sun
creator: Ya Xu
uri: https://doi.org/10.7717/peerj.20215
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Huang et al.

title: Knowledge and competence in vestibular rehabilitation: a cross-sectional study of physical therapy interns
link: https://peerj.com/articles/20213
last-modified: 2025-11-04
description: BackgroundVestibular rehabilitation (VR) is a specialized physical therapy practice area that requires comprehensive knowledge and clinical competence to manage vestibular disorders effectively, which significantly impacts patients’ quality of life. Discrepancies between knowledge and competence among physical therapy interns remain under-researched. Addressing this gap is essential for identifying specific educational deficiencies, improving training programs, and enhancing clinical preparedness.ObjectiveThis study aimed to examine the knowledge and competence of Saudi physical therapist (PT) interns in VR.MethodsA cross-sectional survey was conducted among PT interns (n = 233), and VR knowledge was assessed through self-reports and objective testing. The questionnaire, developed via the Delphi method, included items specifically designed to assess competence in and knowledge of VR. Statistical analyses included descriptive statistics, multiple response analysis, and multiple linear regression to explore demographic data, knowledge, and competence predictors. The data were analyzed via JASP 18.1.1.ResultsCompetence showed a high mean score of 5.35 out of 8 (67%). In contrast, case report knowledge was low at 0.58/2 (29%), VR tests learned during academic years averaged 4.17 out of 20 (28%), while those learned during the internship averaged 2.43 out of 20 (17%). Similarly, treatment approaches and maneuvers for vestibular-related disorders learned during academic years averaged 2.47 out of 12 (25%), while those learned during the internship averaged 1.69 out of 12 (19%), indicating limited knowledge and skills in vestibular rehabilitation across both academic and clinical training phases. A simultaneous-entry multiple regression indicated that the predictor set significantly explained competence, F(12, 219) = 5.96, p < .001, accounting for 24.6% of the variance (adjusted R2 = .21, RMSE = 1.78). Internship vestibular-test knowledge (B = 0.25, β = .32, p < .001) and workshop attendance (B = 0.82, p = .006) were the only unique contributors. A companion model for case-report knowledge was also significant, F(12, 219) = 2.50, p = .004, but modest (adjusted R2 = .07, RMSE = 0.74); workshop attendance had a positive effect (B = 0.49, p < .001) while possession of a professional physical-therapy degree predicted lower scores (B =  − 1.06, p = .045), with all other variables non-significant.ConclusionThe findings of this study underscore the need to implement structured academic education in VR. Integrating formal education with hands-on experiences in VR curricula could enhance knowledge and competence among PT interns.
creator: Danah Alyahya
creator: Arwa Alharbi
creator: Faizan Kashoo
creator: Shaikha Alsaheli
creator: Faisal Mubarak AlMubarak
creator: Rehab Aljuhni
uri: https://doi.org/10.7717/peerj.20213
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Alyahya et al.

title: Geographic disparities and predictors of suicide mortality risk in Florida: spatial scan statistics and negative binomial modeling
link: https://peerj.com/articles/20075
last-modified: 2025-11-04
description: BackgroundFlorida ranks 17th in suicide mortality risk in the United States, with 14.8 suicide deaths per 100,000 persons. Geographic disparities in suicide mortality across the US are well-documented and are partly attributed to the uneven distribution of risk factors. However, limited data exist on such disparities and associated predictors within Florida, despite their importance for guiding targeted prevention efforts. This study aimed to investigate county-level geographic disparities in suicide mortality risk in Florida and identify predictors of these disparities.MethodsThis retrospective ecological study used data from the Florida Department of Health. County-level age-adjusted suicide mortality risks and spatial empirical Bayesian-smoothed risks were calculated for three time periods: 2011–2013, 2014–2016, and 2017–2019. Tango’s spatial scan statistics were applied to identify high-risk clusters. A negative binomial regression model was used to examine county-level predictors of suicide mortality risk for the 2017–2019 period.ResultsStatewide age-adjusted suicide mortality risk increased from 22.6 to 24.3 per 100,000 persons over the study period. Counties in the northwest, northeast, southwest, and parts of central Florida consistently exhibited high mortality risks. Suicide mortality risk was significantly higher in counties with larger proportions of residents aged 45–64 years and ≥65 years, those reporting excessive drinking, frequent mental distress, or veteran status.ConclusionThis study identified geographic disparities and key predictors of suicide mortality risk across Florida counties. These findings can inform policymakers, healthcare providers, and community organizations in designing and implementing targeted suicide prevention programs tailored to the specific needs of high-risk communities.
creator: Howard Onyuth
creator: Corey Day
creator: Nirmalendu Deb Nath
creator: Agricola Odoi
uri: https://doi.org/10.7717/peerj.20075
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Onyuth et al.

title: Serum growth differentiation factor 15 trajectory predicts 28-day mortality in critically ill patients: a multicenter cohort study
link: https://peerj.com/articles/20317
last-modified: 2025-11-03
description: BackgroundGrowth differentiation factor 15 (GDF15) has been linked to critical illnesses, particularly cardiovascular and infectious diseases, but its dynamic patterns and prognostic value in critically ill patients remain unclear. This study investigates the predictive utility of serum GDF15 trajectories for 28-day mortality among patients in the intensive care unit (ICU).MethodsIn this multicenter, prospective cohort study, ICU patients were enrolled, and serum GDF15 trajectories during the first week were analyzed using group-based trajectory modeling (GBTM). The association between trajectory subtypes and 28-day mortality was assessed through hierarchically adjusted multivariable logistic regression. A cumulative index, “GDF15-load,” was introduced to quantify overall GDF15 exposure and compared with the Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores. The correlation between initial GDF15 levels (GDF15-D1) and GDF15-load was evaluated using Spearman’s correlation test. Predictive performance was assessed via the area under the receiver operating characteristic curve (AUROC), and feature importance was interpreted using Shapley Additive Explanations (SHAP).ResultsAmong 1,973 patients, 493 comprised the cohort for development with full serum profiles on days 1, 3, and 7. Four GDF15 trajectory subtypes were identified: low-maintenance (LM), medium-maintenance (MM), high-increase (HI), and high-persistent (HP). Trajectory subtypes showed significant differences in inflammatory markers, organ dysfunction, and 28-day mortality, with the HI and HP groups having the worst outcomes. GDF15-load increased progressively from LM to HP and emerged as the most important predictor of 28-day mortality, not inferior to APACHE II and SOFA scores. GDF15-D1 was strongly correlated with GDF15-load (Spearman r = 0.778) and demonstrated robust predictive value, particularly in postoperative ICU patients, where its combination with APACHE II or SOFA further improved prognostic accuracy.ConclusionsSerum GDF15 trajectory and GDF15-load are robust predictors of 28-day mortality in ICU patients. GDF15-D1 strongly reflects cumulative GDF15 burden and provides a rapid, practical tool for early risk stratification, especially in postoperative ICU patients. These findings support the use of GDF15 as both a dynamic and point-of-care biomarker in intensive care settings.
creator: Qinxue Wang
creator: Jiawei Wang
creator: Yuhan Zhao
creator: Yuanze Ma
creator: Xiang Li
creator: Xinyi Chang
creator: Nan Zheng
creator: Yong Ji
creator: Yi Han
uri: https://doi.org/10.7717/peerj.20317
license: https://creativecommons.org/licenses/by/4.0/
rights: © 2025 Wang et al.

title: Comparative dosimetric evaluation of single-beam dual-arc versus dual-beam single-arc volumetric modulated arc therapy strategies in lung stereotactic body radiotherapy using Monaco
link: https://peerj.com/articles/20311
last-modified: 2025-11-03
description: Background and ObjectiveIn stereotactic body radiotherapy (SBRT) for lung cancer, the choice of volumetric modulated arc therapy (VMAT) optimization strategy is critical for achieving optimal target dose coverage while minimizing exposure to normal tissues. This study aims to compare the dosimetric performance and plan complexity of two VMAT optimization strategies in Monaco: single-beam dual-arc (1B2A) versus dual-beam single-arc (2B1A).MethodsA retrospective analysis was conducted on 50 lung cancer patients treated with SBRT (prescription dose: 50 Gy in 5 fractions). Two VMAT plans were re-optimized using the Monaco treatment planning system: the 1B2A plan (single-beam dual-arc, collimator angle 10°) and the 2B1A plan (dual-beam single-arc, collimator angles 10° and 350°). Dosimetric parameters, including target dose coverage, conformity index (CI), and gradient index (GI), were evaluated for the internal target volume (ITV) and planning target volume (PTV). Dose metrics for organs at risk (OARs) were also analyzed. Plan complexity was assessed based on monitor units (MU), number of control points, complexity index, and integral dose to normal tissues.ResultsSignificant dosimetric differences were observed between the two strategies. When normalized to ensure the prescribed 50 Gy isodose line covers 95% of the PTV volume, the high-dose parameters (D1%, D50%, Dmean) of the ITV and PTV were significantly lower in the 1B2A group compared to the 2B1A group (p < 0.001), indicating superior dose distribution with the 2B1A approach. Although the 1B2A plan exhibited marginally better CI, GI, and low-dose lung sparing (V5–V30), these differences were minimal and clinically insignicant. No substantial dierences were found in the dose sparing of other OARs, including the spinal cord, heart, and ribs. Additionally, the 1B2A plan required signicantly higher MU (+15.5%, p < 0.001) and had greater plan complexity (+9.47%, p < 0.001), suggesting lower treatment efficiency.ConclusionsIn peripheral lung cancer SBRT, the dual-beam single-arc (2B1A) strategy offers superior target dose distribution and treatment efficiency, making it a preferable optimization approach.
creator: Jieni Ding
creator: Yanqiu Huang
creator: Qiang Li
creator: Weijun Chen
creator: Kainan Shao
uri: https://doi.org/10.7717/peerj.20311
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Ding et al.

title: A comparison of spinal and lower extremity biomechanics during maximal and sub-maximal deadlifts among strength-trained women
link: https://peerj.com/articles/20279
last-modified: 2025-11-03
description: BackgroundPrevious studies have examined changes in biomechanical variables in response to different deadlift loads, yet, the effect of sub-maximal and maximal loads on potential deviation in lifting technique remain inadequately understood.MethodsTherefore, this study compared barbell and joint kinematics, net joint moments (NJMs), and surface electromyography (sEMG) amplitude during 70%, 90%, and 100% of three-repetition maximum (3RM) load using statistical parametric mapping. Twelve strength-trained women (age: 23.18 ± 3.46 years, height: 166.72 ± 2.90 cm, body mass: 68.18 ± 7.67 kg) lifted 72.5 ± 9.3 kg, 93.9 ± 16.6 kg, and 102.9 ± 17.6 kg s at 70%, 90%, and 100% of 3RM deadlifts, respectively.ResultsThe main findings revealed that the maximal load resulted in a significant increase in lower thoracic flexion angles and erector spinae sEMG amplitudes compared to the sub-maximal loads. Additionally, significantly lower hip NJMs were observed with a 70% load compared to 90% and 100% loads.ConclusionTherefore, increasing loads beyond 90% of 3RM might not be necessary if the goal is to train hip extensor strength through deadlifting. Deadlifting loads beyond 90% of 3RM may be achieved by increasing spinal flexion. This posture may allow strength-trained women to lift beyond the strength capacity of their hip extensors during the final repetition of a 3RM deadlift.
creator: Andreas H. Gundersen
creator: Roland van den Tillaar
creator: Hallvard Falch
creator: Stian Larsen
uri: https://doi.org/10.7717/peerj.20279
license: https://creativecommons.org/licenses/by/4.0/
rights: ©2025 Gundersen et al.