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The right way to ride the wrong bike: An exploration of Klein’s ‘unridable’ bicycle

Professor Richard Klein and his students built a bicycle with a rather interesting feature: no one was able to ride it. A prize was offered. Hundreds of students and cycling enthusiasts attempted it. Years passed, and the prize money grew. Klein’s rear-steered bicycle became a canonical example of how non-minimum phase systems can be difficult and sometimes nearly impossible to control. It has been lauded as a particularly effective educational example in which students can experience the loss of controllability in a seemingly simple, albeit unorthodox bicycle. The primary result of the work reported here is a demonstration that it is possible for a human of modest athletic ability to ride Klein’s unridable bicycle, to keep it balanced, and to control its direction of travel. There is a secret to riding Klein’s rear-steer bicycle. The secret is revealed through an exploration of the dynamics and control of the bike that contains three elements: (1) modeling the physics of the actively steered bicycle as an inverted pendulum riding atop a carriage; (2) recognizing that the steer kinematics leads to competing physical mechanisms which an aspiring rider might exploit; and (3) examining limitations of controllability and stabilizability of the system from a state space perspective. From this vantage point, one can devise a novel strategy, based on a component of lateral acceleration that dominates at low speed, for riding the so-called “unridable” bike and solving Klein’s puzzle. The work adds a new chapter on the dynamics and control of the rear-steered bicycle, a problem of academic interest.

Dropping the baton: Cognitive biases in emergency physicians

Introduction Clinical medicine is becoming more complex and increasingly requires a team-based approach to deliver healthcare needs. This dispersion of cognitive reasoning across individuals, teams and systems (termed “distributed cognition”) means that our understanding of cognitive biases and errors must expand beyond traditional “in-the-head” individual mental models and focus on a broader “out-in-the-world” context instead. To our knowledge, no qualitative studies thus far have examined cognitive biases in clinical settings from a team-based sociocultural perspective. Our study therefore seeks to explore how cognitive biases and errors among emergency physicians (EPs) arise due to sociocultural influences and lapses in team cognition. Methodology Our study team comprised four EPs of different seniorities from three different institutions and local and international academics who provided qualitative methodological guidance. We adopted a constructivist paradigm and employed a reflexive thematic analysis approach which acknowledged our researcher reflexivity. We conducted seven focus group discussions with 25 EPs who were purposively sampled for maximum variation. Our research question was: How do sociocultural factors lead to cognitive biases and medical errors among EPs? Results Our themes coalesce around sociocultural pressures related to team psychology. In theme one, the EP is compelled by sociocultural pressures to blindly trust colleagues. In the second, the EP is obliged by cultural norms to be “nice” and neatly summarise cases into illness scripts during handovers. In the last, the EP is under immense pressure to follow conventional wisdom, comply with clinical protocols and not challenge inpatient specialists. Conclusion Cognitive biases and errors in clinical decision-making can arise due to lapses in distributed team cognition. Although this study focuses on emergency medicine, these pitfalls in team-based cognition are relevant across the entire continuum of care and across all specialties of medicine. The hyperacute nature of emergency medicine merely exacerbates and condenses these into a compressed timeframe. Indeed, similar relays are run every day in every discipline of medicine, with the same unified goal of doing the best for our patients while not committing cognitive errors and dropping the baton.

Incident duration prediction through integration of uncertainty and risk factor evaluation: A San Francisco incidents case study

Predicting incident duration and understanding incident types are essential in traffic management for resource optimization and disruption minimization. Precise predictions enable the efficient deployment of response teams and strategic traffic rerouting, leading to reduced congestion and enhanced safety. Furthermore, an in-depth understanding of incident types helps in implementing preventive measures and formulating strategies to alleviate their influence on road networks. In this paper, we present a comprehensive framework for accurately predicting incident duration, with a particular emphasis on the critical role of street conditions and locations as major incident triggers. To demonstrate the effectiveness of our framework, we performed an in-depth case study using a dataset from San Francisco. We introduce a novel feature called "Risk" derived from the Risk Priority Number (RPN) concept, highlighting the significance of the incident location in both incident occurrence and prediction. Additionally, we propose a refined incident categorization through fuzzy clustering methods, delineating a unique policy for identifying boundary clusters that necessitate further modeling and testing under varying scenarios. Each cluster undergoes a Multiple Criteria Decision-Making (MCDM) process to gain deeper insights into their distinctions and provide valuable managerial insights. Finally, we employ both traditional Machine Learning (ML) and Deep Learning (DL) models to perform classification and regression tasks. Specifically, incidents residing in boundary clusters are predicted utilizing the scenarios outlined in this study. Through a rigorous analysis of feature importance using top-performing predictive models, we identify the "Risk" factor as a critical determinant of incident duration. Moreover, variables such as distance, humidity, and hour demonstrate significant influence, further enhancing the predictive power of the proposed model.

Self /other recognition and distinction in adolescents with anorexia nervosa: A pilot study using a double mirror paradigm

Background Abnormalities in body perception in patients affected by anorexia nervosa have been widely studied, but without explicit reference to their relationship to others and the social processes involved. Yet, there are a several arguments supporting impairments in interpersonal relationships in these patients. Notably, some evidence suggests that self/other distinction (SOD), the ability to distinguish one’s own body, actions and mental representations from those of others could be impaired. But research remains scarce in this area. Material and methods A single-centre, prospective pilot study was conducted to investigate, for the first time, self-recognition and SOD in seven adolescents with anorexia nervosa compared with matched healthy controls (HCs) using the "Alter Ego"TM double mirror paradigm. This innovative device allows the progressive morphing of one’s own face to that of another and vice versa between two subjects that interact on opposite sides of the device. Two judgement criteria were used: 1) M1: the threshold at which subjects start to recognize their own face during other-to-self morphing, and 2) M2: the threshold at which subjects start to recognize the other’s face during self-to-other morphing. In a second part, SOD was reassessed during five different sensorimotor tasks aimed at increasing body self-consciousness in participants with anorexia nervosa. Results The results showed that the participants with anorexia nervosa exhibited earlier self-recognition in the other-to-self sequence and delayed other-recognition in the self-to-other sequence. Furthermore, in contrast with that of HCs, the critical threshold for switching between self and other varied with the direction of morphing in anorexia nervosa participants. Finally, when participants with anorexia were seated in a chair with a backrest and footrest strengthening the median axis of their body, the self-recognition threshold (M1) increased significantly, approaching that of controls. Conclusions Although additional research is needed to replicate the results of this pilot study, it revealed the first behavioural evidence of altered SOD in individuals affected by anorexia nervosa through an embodied, semiecological face-recognition paradigm. The relationships between anomalies in body perception and alterations in interpersonal relationships are discussed within an integrative framework from phenomenology to neuroscience, and new research and therapeutic perspectives are presented.

Comparison of core temperature using tracheal thermometer and pulmonary artery catheter in adult patients undergoing coronary artery bypass graft surgery

Background Monitoring core temperature is important for patients under anesthesia. Esophageal and pulmonary artery blood temperatures can be used for measuring core temperature during general anesthesia. However, these methods pose challenges, especially when the placement of an esophageal thermometer and pulmonary artery catheter (PAC) is either impractical or not the preferred approach. An endotracheal tube (ETT) with a thermometer on the cuff allows for the measurement of tracheal temperature, providing a suitable alternative to core temperature measurement. This study aimed to assess the clinical reliability and accuracy of the thermometer in the ETT in comparison to the core temperature measured using a PAC. Methods Eleven patients who underwent coronary artery bypass graft (CABG) surgery were enrolled in this study. The patients were intubated using an ETT equipped with a thermometer on the cuff, and a PAC was inserted. Temperature measurements of both the trachea and pulmonary artery blood were recorded at 5-minute intervals for 1 hour before starting cardiopulmonary bypass. The agreement between the two temperature measurement methods was investigated using the Bland-Altman plot with multiple measurements per subject, and the correlation was evaluated using the concordance correlation coefficient (CCC). Results Eleven patients with a total of 143 pairs of data were included for analysis. The mean difference between the tracheal and pulmonary artery temperatures was −0.10°C. The 95% limit of agreement (LoA), calculated as ± 1.96 standard deviation, ranged from −0.35°C to 0.15°C. The 95% confidence interval for the lower and upper LoA was −0.51°C to −0.27°C and 0.07°C to 0.31°C, respectively. The maximum allowed difference (Δ) was set at 0.5°C. The majority of temperature differences fell within the LoA and were well below the maximum allowed difference. The CCC was 0.95, which indicates a substantial strength of agreement. Conclusions The agreement between the tracheal and pulmonary artery temperature measurements using the ETT thermometer and pulmonary artery catheter, respectively, was found to be clinically reliable and accurate. Therefore, the tracheal temperature measurement can effectively represent the core temperature of the patients. Employing an ETT equipped with a thermometer on the cuff can serve as a reliable and independent method for measuring core temperature. Trial registration Clinical trial registration number: NCT05595616.

Seroconversion and dynamics of IgG anti-SARS-CoV-2 antibodies during the pandemic: A two-month observation cohort study on the population of Sleman in Indonesia

Background This study describes the seroconversion and serodynamics of IgG antibodies against the RBD of SARS-CoV-2 in the general population of Sleman District, Yogyakarta Special Province. We aim to identify possible factors that correlate with the seroconversion and serodynamics of IgG antibodies against the RBD of SARS-CoV-2. Methods We performed a longitudinal study of the population at Health and Demographic Surveillance System (HDSS) Sleman, Yogyakarta, Indonesia. Study subjects were recruited between April and December 2021 using convenience sampling and were followed up 2 times, i.e. 4–5 and 8–9 weeks. The inclusion criteria for subjects were age ≥ 18 years, absence of flu-like symptoms, and negative COVID-19 by using GeNose C19® screening. A community-based survey on demographics, comorbidities and smoking habits were documented at baseline, while a history of vaccination, COVID-19-related symptoms, mobility, and preventive measures, weight and height as well as a venous blood draw, were collected at each visit. The anti-RBD-SARS-CoV-2 IgG antibody concentration from blood plasma was measured using chemiluminescent microplate immunoassay (CMIA). Descriptive analysis was performed based on IgG seropositivity by using chi-squared test or Fisher’s exact test, as appropriate. Logistic regression was subsequently performed to identify factors that were correlated with IgG seropositivity. Further, a grouping of subjects based on IgG seropositivity was done to analyze factors that might correlate with seroconversion and serodynamics of anti-RBD-SARS-CoV-2 IgG antibody. A P value ≤ 0.05 was considered to indicate a significant difference. Results Three hundred eighty-five (385) participants were analyzed. At baseline, 307 out of 385 (79.7%) subjects were seropositive for the IgG antibody against the RBD of SARS-CoV-2. Descriptive analysis showed that sex, marital status, smoking habits, obesity, vaccination status, and preventive measures were different between the IgG anti-RBD-SARS-CoV-2 seropositive and negative individuals (p≤ 0.05). Further analysis showed that, vaccination was the factor most strongly correlated with seropositivity [OR = 20.58; 95% CI 10.82, 39.15]. Based on the correlation, we separated subjects into 4 groups. Group 1 (seronegative-unvaccinated individuals; 50 subjects); Group 2 (seronegative-vaccinated individuals; 27 subjects); Group 3 (seropositive-unvaccinated individuals; 25 subjects); and Group 4 (seropositive-vaccinated individuals; 282 subjects). During monitoring, 27/49 (55.10%), 5/25 (20%), 9/22 (40.91%), and 27/257 (10.51%) of subjects in Group 1, 2, 3, and 4 respectively, received 1 or 2 doses of COVID19 vaccine. When comparing seroconversion at baseline and monitoring 2, positive IgG seroconversion was observed in Group 1 (from 0/51 (0%) to 23/49 (46.94%)) and Group 2 (from 0/27 (0%) to 10/25 (40%)), but negative seroconversion was observed in Group 4 (from 282/0 (100%) to 248/257 (96.50%)); while, all subjects in Group 3 remained seropositive at the end of monitoring. This evidence suggested for hybrid immunity, on which infection and vaccine simultaneously contributes to anti-RBD-SARS-CoV-2 IgG seroconversion. Conclusions A high seroprevalence of the IgG antibody against RBD-SARS-CoV-2 in the Sleman population was found to correlate with COVID-19 vaccination and as infection occurred, thus enhancing hybrid immunity. We also identified nonresponder and rapid antibody decaying individuals, that call for targeted vaccinations in addition to annual universal boosting.

Correction: Emphasizing speed or accuracy in an eye-tracking version of the Trail-Making-Test: Towards experimental diagnostics for decomposing executive functions

Finite mixtures of functional graphical models: Uncovering heterogeneous dependencies in high-dimensional data

Graphical models have been widely used to explicitly capture the statistical relationships among the variables of interest in the form of a graph. The central question in these models is to infer significant conditional dependencies or independencies from high-dimensional data. In the current literature, it is common to assume that the high-dimensional data come from a homogeneous source and follow a parametric graphical model. However, in real-world context the observed data often come from different sources and may have heterogeneous dependencies across the whole population. In addition, for time-dependent data, many work has been done to estimate discrete correlation structures at each time point but less work has been done to estimate global correlation structures over all time points. In this work, we propose finite mixtures of functional graphical models (MFGM), which detect the heterogeneous subgroups of the population and estimate single graph for each subgroup by considering the correlation structures. We further design an estimation method for MFGM using an iterative Expectation-Maximization (EM) algorithm and functional graphical lasso (fglasso). Numerically, we demonstrate the performance of our method in simulation studies and apply our method to high-dimensional electroencephalogram (EEG) dataset taken from an alcoholism study.

Evaluation of efficacy of GCSF in reducing neutropenia among carcinoma patients undergoing anti-cancer chemotherapy. A prospective cohort study

The use of granulocyte colony-stimulating factor (GCSF) to control febrile neutropenia (FN) caused by anti-cancer chemotherapy is well documented but it still needs to evaluated with respect to the specific type of cancer and chemotherapeutic agents. The present study evaluates the efficacy of adjunctive GCSF for treating FN after taking anticancer therapy by measuring clinical, hematological and microbiological outcomes. It is a single center study conducted at Hayatabad Medical Complex (HMC), Peshawar, Pakistan. Adult patients of both genders, suffering from different types of sarcomas and taking anticancer chemotherapy were included in the study. The study was conducted between January 2023 and January 2024. Baseline data including demographic data, medication history and hematological evaluation of all the patients was recorded at the time of enrolment. Primary outcomes of the study were the extent of absolute neutrophil count (ANC) recovery, duration and severity of neutropenia (grade IV), period to fever resolution. After the therapy (with and without adjunctive GCSF) clinical outcomes, hematological evaluation and microbiological data was compared and evaluated. All the data was statistically analyzed by SPSS (IBMS, version 20). A total number of 120 patients were investigated out of which data of 109 patients was included. Out of 109 patients, 64 (58.72%) received adjunctive GCSF therapy, and 45 (41.28%) did not receive adjunctive GCSF. Comparison of the data showed that the patients receiving adjunctive GCSF had a significant improvement ANC recovery time, better recovery of fever and patients were free of infections. This study concluded that adjunctive GCSF therapy benefits the patients undergoing anticancer treatment for different types of carcinoma.

Nasopharyngeal carriage of Streptococcus pneumoniae among Brazilian children: Interplay with viral co-infection

Nasopharyngeal transmission of Streptococcus pneumoniae is a prerequisite for the development of pneumococcal diseases. Previous studies have reported a relationship between respiratory viruses and S. pneumoniae infections. However, there are few studies on this issue among healthy children. This study aimed to examine the relationships between these agents in healthy children from Southern Brazil. This cohort study included 229 nasopharyngeal samples collected from children aged 18–59 months at baseline. S. pneumoniae was detected using bacterial culture, whereas respiratory viruses were identified using quantitative polymerase chain reaction. A questionnaire was used at the time of sample collection and medical records were reviewed 14 days after participant inclusion. The prevalence of pneumococcal carriage was 63.7% (146/229), while respiratory viruses were detected in 49.3% (113/229) of the children. Respiratory viruses were more frequently found among pneumococcal carriers than among non-carriers (54.4% vs. 39.7%, p = 0.033). Additionally, rhinovirus (hRV) was more frequent among the pneumococcal carriers (39% vs. 21.7%, p = 0.012), and the presence of human bocavirus (hBOV) alone was associated with the absence of pneumococcal carriage (2.7% vs. 10.8%, p = 0.016). No differences were found in the frequency of pneumococcal carriage, respiratory virus detection, or the co-occurrence of clinical symptoms and diagnosis in the participants 14 days after specimen collection. Our findings revealed a positive relationship between pneumococcal carriage and respiratory virus detection, particularly for hRV. However, we did not observe a relationship between nasopharyngeal respiratory viruses and pneumococci detection during medical appointments, respiratory symptoms, or diseases. This study was one of the first investigations in Latin America to explore the relationship between respiratory viruses and pneumococcal carriage in a healthy children.

Correction: A secreted proteomic footprint for stem cell pluripotency

Climate engineering faces hostility — here’s how scientists say it might move forwards

Correction: Self-reported food intolerance, dietary supplement use and malnutrition in chronic inflammatory bowel diseases: Findings from a cross-sectional study in Lebanon

Virological outcomes of antiretroviral therapy and its determinants among HIV patients in Ethiopia: Implications for achieving the 95–95–95 target

Background Despite significant advancements in HIV treatment, virological outcomes remain a critical issue. Ethiopia did not meet the 90:90:90 targets set for 2020, which aimed for 90% of people on antiretroviral therapy to achieve viral suppression. As the country shifts its focus toward the 95:95:95 targets for 2030—seeking to achieve 95% viral suppression among those on ART—it is crucial to deepen our understanding of viral suppression and the factors that influence it. Methods Virological suppression was examined among 410 HIV-positive individuals on ART using the EPHIA survey. The survey employed a two-stage, stratified sampling design across urban areas in nine regions and two city administrations. Data analysis was conducted with STATA version 18, and multicollinearity was assessed using variance inflation factors. A logistic regression model identified significant determinants of viral suppression, with variables having a p-value of ≤0.05 considered statistically significant in the multivariable analysis. Results The findings revealed that 364 participants (88.78%) achieved viral suppression. Key determinants of virological outcomes included a higher wealth level (AOR = 2.67, 95% CI: 1.15–6.22), the presence of active TB (AOR = 0.27, 95% CI: 0.14–0.57), hepatitis B virus (AOR = 0.20, 95% CI: 0.10–0.31), and the utilization of HIV support group care (AOR = 3.14, 95% CI: 1.35–6.30). Conclusion Viral suppression among HIV patients is 88.78%, which even falls short of the WHO’s 90% target for 2020, indicating the substantial work required to achieve 95% by 2030. To improve virological outcomes, it is crucial to increase support for low-income patients, enhance management of co-infections like TB and hepatitis B, and expand access to HIV support groups for better adherence and care.

A systematic review to identify research gaps in studies modeling MenB vaccinations against Neisseria infections

The genus Neisseria includes two major human pathogens: N. meningitidis causing bacterial meningitis/septicemia and N. gonorrhoeae causing gonorrhoea. Mathematical models have been used to simulate their transmission and control strategies, and the recent observation of a meningococcal B (MenB) vaccine being partially effective against gonorrhoea has led to an increased modeling interest. Here we conducted a systematic review of the literature, focusing on studies that model vaccination strategies with MenB vaccines against Neisseria incidence and antimicrobial resistance. Using journal, preprint, and grey literature repositories, we identified 52 studies that we reviewed for validity, model approaches and assumptions. Most studies showed a good quality of evidence, and the variety of approaches along with their different modeling angles, was assuring especially for gonorrhoea studies. We identified options for future research, including the combination of both meningococcal and gonococcal infections in studies to have better estimates for vaccine benefits, and the spill over of gonorrhoea infections from the heterosexual to the MSM community and vice versa. Cost-effectiveness studies looking at at-risk and the wider populations can then be used to inform vaccine policies on gonorrhoea, as they have for meningococcal disease.

Barriers and facilitators to implementing comprehensive sex education in Texas public schools: A qualitative study

Introduction In Texas, the adolescent birth rate is higher than the national average and STIs have steadily increased over the last decade. Sex education is not mandated in Texas and the majority of public schools provide an abstinence-based sex education. Comprehensive sexuality education (CSE) programs are widely endorsed by national and global health organizations and research has shown that they are more effective in reducing poor sexual health outcomes than abstinence-based programs. The purpose of this study is to identify barriers and facilitators to implementing CSE at local and state levels in Texas. Methods Qualitative study design consisting of ten semi-structured interviews with eleven key informants (n = 11) conducted in 2021. Results Three barriers- ideological opposition to CSE, discrimination against LGBTQ+ people, myths and misconceptions about CSE- and two facilitators- champions, collaboration with community stakeholders- to implementing CSE policy were identified. Conclusion Study findings provide insight into the opposition faced by sex education advocates, which often stems from myths and misperceptions of CSE content and the stigmatization of sexual and gender minoritized groups. Parents, youth, medical professionals, and academic researchers are instrumental in dispelling sex education myths and misperceptions and engaging with community stakeholders.

Day-to-day dynamics of fetal heart rate variability to detect chorioamnionitis in preterm premature rupture of membranes

Background Chorioamnionitis is recognized as a major consequence of preterm premature rupture of membranes (PPROM), and a frequent cause of neonatal morbidity and mortality. The association between fetal heart rate (FHR) and chorioamnionitis remains unclear. Objectives The aim of this study was to evaluate the dynamics of FHR in a PPROM population at the approach of delivery according to the presence or absence of chorioamnionitis. Materials & methods 120 pregnant women with PPROM between 26 and 34 weeks’ gestation were enrolled in this multicenter prospective unblinded study. All participants were fully informed of the study’s objectives. 39 of the 120 patients were included in the analysis of FHR recordings. The analysis consisted of extracting features from computerized FHR analysis (cFHR) and fetal heart rate variability analysis (FHRV) in the temporal, frequency and nonlinear domains. Then, each set of features was analyzed separately using the multiple factor analysis, where three groups were defined as the feature set for days 0, -1 and -2 prior to birth. The distances between the global projection and the projections for each day were computed and used in the ROC analysis to distinguish chorioamnionitis from non-chorioamnionitis group. Results The results showed that there were significant differences in certain features between populations with and without chorioamnionitis. The distinction between the two populations reached an area under the curve (AUC) of only 37% [34–40] for cFHR features and 63% [59–66] for time-domain FHRV features when comparing all stages of chorioamnionitis to non-chorioamnionitis subjects. When only stage 3 chorioamnionitis was compared to non-chorioamnionitis patients, the AUC reached 90% [88–93] for nonlinear-domain and 84% [82–87] for time-domain FHRV features, whereas it was limited to 71% [68–74] using cFHR features. Conclusion The present study suggests that the HRV features are more reliable for diagnosing chorioamnionitis than cFHR, and that the assessment of features dynamics over several days is an interesting tool for detecting chorioamnionitis. Further study should be carried out on a larger sample to confirm these findings, improve the diagnostic performance of chorioamnionitis and help clinicians decide on delivery criteria.

Correction: Exploring the impact of trait number and type on functional diversity metrics in real-world ecosystems

Abrupt changes in biomass burning during the last glacial period

Impact of regenerative procedure on the healing process following surgical root canal treatment: A systematic review and meta-analysis

Introduction Different Guided Tissue Regeneration (GTR) procedures, such as membranes, bone substitute materials, and Autologous Platelet Concentrates (APCs), have been applied after surgical root canal treatment (SRCT), which produce different outcomes. This study aimed to evaluate the impact of regenerative procedures on the healing process following SRCT. Methods A comprehensive search of PubMed, Embase, Scopus, Cochrane, and the Web of Science found Randomized Controlled Trials (RCTs) published until February 25, 2024. Manual searches were also conducted. Our main outcome was SRCT success or failure after GTR procedures. The Risk Ratio (RR) and failure rate meta-analysis used a fixed effects model with a 95% confidence interval (CI). Subgroup analyses were conducted based on the use of different GTR procedures for varying lesion types in SRCT. Results Out of 1,605 records, 16 studies with 690 lesions were included. Overall, GTR procedures significantly improved healing after SRCT in both 2D (RR: 0.50; 95% CI, 0.34–0.73; P < 0.001) and 3D evaluation methods (RR: 0.36; 95% CI, 0.15–0.90; P < 0.001) with no significant difference between the two methods. Conclusion GTR significantly improved SRCT healing regardless of the evaluation method used. Combining collagen membranes with bovine bone-derived hydroxyapatite significantly enhanced the healing process. Additionally, GTR procedures significantly improve healing in through-and-through lesions.