Assessment of salivary cortisol dynamics in an infantry training exercise: a pilot study

INTRODUCTION

Measuring cortisol during military training offers insights into physiological responses to stress. We attempted precisely timed, cortisol awakening response (CAR) and pre-sleep cortisol (PSC), and diurnal slope (peak morning minus evening cortisol), during a British Army exercise. We aimed to understand cortisol dynamics and evaluate the feasibility of CAR and PSC in this environment.

METHOD

Setting: high-intensity, 10-day infantry exercise. Participants: regular infantry soldiers exercising (EX, n=25) or headquarters-based (HQ, n=6). Participants undertook PSC and WAKE and WAKE+30 min samples after 1-2 days, 5-6 days and 9-10 days. Wrist-worn GENEActiv accelerometers were used to assess sleep duration in EX only. Samples taken ±15 min from prespecified time points were deemed adherent. Validated questionnaires were used to measure resilience and perceived stress. Cortisol and cortisone were measured simultaneously by liquid chromatography tandem mass spectrometry.

RESULTS

From adherent participants' samples, CAR was positive and tended to decrease as the exercise progressed. From all available data, HQ demonstrated greater diurnal slope than EX (F=7.68, p=0.02), reflecting higher morning cortisol (F=4.72, p=0.038) and lower PSC (p=0.04). No differences were seen in cortisol:cortisone ratio. 26.1% of CAR samples were adherent, with moderately strong associations between adherence and stress (r=0.41, p=0.009) but no association between adherence and day of exercise (χ2=0.27, p=0.8), sleep duration (r=-0.112, p=0.43) or resilience (r=-0.79, p=0.75). Test-retest reliability ratings for CAR were Cronbach's α of 0.48, -11.7 and 0.34 for the beginning, middle and end of the exercise, respectively.

CONCLUSIONS

We observed a reduction in morning cortisol and decreased diurnal slope during a high-intensity military exercise, compared with the HQ comparator cohort in whom diurnal slope was preserved. A carefully timed CAR was not feasible in this setting.

Disability, program access, empathy and burnout in US medical students: A national study

OBJECTIVE

The objective of this study is to investigate whether self-disclosed disability and self-reported program access are associated with measures of empathy and burnout in a national sample of US medical students.

METHODS

The authors obtained data from students who responded to the Association of Medical Colleges (AAMC) Year 2 Questionnaire (Y2Q) in 2019 and 2020. Data included demographic characteristics, personal variables, learning environment indicators, measures of burnout (Oldenburg Burnout Inventory for Medical Students), empathy (Interpersonal Reactivity Index) and disability-related questions, including self-reported disability, disability category and program access. Associations between disability status, program access, empathy and burnout were assessed using multivariable logistic regression models accounting for YQ2 demographic, personal-related and learning environment measures.

RESULTS

Overall, 23 898 (54.2%) provided disability data and were included. Of those, 2438 (10.2%) self-reported a disability. Most medical students with disabilities (SWD) self-reported having program access through accommodations (1215 [49.8%]) or that accommodations were not required for access (824 [33.8%]). Multivariable models identified that compared with students without disabilities, SWD with and without program access presented higher odds of high exhaustion (1.50 [95% CI, 1.34-1.69] and 2.59 [95% CI, 1.93-3.49], respectively) and lower odds of low empathy (0.75 [95% CI, 0.67-.85] and 0.68 [95% CI, 0.52-0.90], respectively). In contrast, multivariable models for disengagement identified that SWD reporting lack of program access presented higher odds of high disengagement compared to students without disabilities (1.43 [95% CI, 1.09-1.87], whereas SWD with program access did not (1.09 [95% CI, 0.97-1.22]).

CONCLUSIONS

Despite higher odds of high exhaustion, SWD were less likely to present low empathy regardless of program access, and SWD with program access did not differ from students without disabilities in terms of disengagement. These findings add to our understanding of the characteristics and experiences of SWD including their contributions as empathic future physicians.

Developing a multimodal biosensor for remote physiological monitoring

INTRODUCTION

Several UK military expeditions have successfully used physiological sensors to monitor participant's physiological responses to challenging environmental conditions. This article describes the development and trial of a multimodal wearable biosensor that was used during the first all-female unassisted ski crossing of the Antarctic land mass. The project successfully transmitted remote real-time physiological data back to the UK. The ergonomic and technical lessons identified have informed recommendations for future wearable devices.

METHOD

The biosensor devices were designed to be continuously worn against the skin and capture: HR, ECG, body surface temperature, bioimpedance, perspiration pH, sodium, lactate and glucose. The data were transmitted from the devices to an android smartphone using near-field technology. A custom-built App running on an android smartphone managed the secure transmission of the data to a UK research centre, using a commercially available satellite transceiver.

RESULTS

Real-time physiological data, captured by the multimodal device, was successfully transmitted back to a UK research control centre on 6 occasions. Postexpedition feedback from the participants has contributed to the ergonomic and technical refinement of the next generation of devices.

CONCLUSION

The future success of wearable technologies lies in establishing clinical confidence in the quality of the measured data and the accurate interpretation of those data in the context of the individual, the environment and activity being undertaken. In the near future, wearable physiological monitoring could improve point-of-care diagnostic accuracy and inform critical medical and command decisions.

Relationship between Total Antioxidant Capacity, Cannabinoids and Terpenoids in Hops and Cannabis

Efficient determination of antioxidant activity in medicinal plants may provide added value to extracts. The effects of postharvest pre-freezing and drying [microwave-assisted hot air (MAHD) and freeze drying] on hops and cannabis were evaluated to determine the relationship between antioxidant activity and secondary metabolites. The 2,2-diphenyl-1-picrylhydrazine (DPPH) reduction and ferric reducing ability of power (FRAP) assays were assessed for suitability in estimating the antioxidant activity of extracted hops and cannabis inflorescences and correlation with cannabinoid and terpene content. Antioxidant activity in extracts obtained from fresh, undried samples amounted to 3.6 Trolox equivalent antioxidant activity (TEAC) (M) dry matter^-1 and 2.32 FRAP (M) dry matter^-1 for hops, in addition to 2.29 TEAC (M) dry matter^-1 and 0.25 FRAP (M) dry matter^-1 for cannabis. Pre-freezing significantly increased antioxidant values by 13% (DPPH) and 29.9% (FRAP) for hops, and by 7.7% (DPPH) and 19.4% (FRAP) for cannabis. ANOVA analyses showed a significant (p < 0.05) increase in total THC (24.2) and THCA (27.2) concentrations (g 100 g dry matter^-1) in pre-frozen, undried samples compared to fresh, undried samples. Freeze-drying and MAHD significantly (p < 0.05) reduced antioxidant activity in hops by 79% and 80.2% [DPPH], respectively and 70.1% and 70.4% [FRAP], respectively, when compared to antioxidant activity in extracts obtained from pre-frozen, undried hops. DPPH assay showed that both freeze-drying and MAHD significantly (p < 0.05) reduced the antioxidant activity of cannabis by 60.5% compared to the pre-frozen samples although, there was no significant (p < 0.05) reduction in the antioxidant activity using the FRAP method. Greater THC content was measured in MAHD-samples when compared to fresh, undried (64.7%) and pre-frozen, undried (57%), likely because of decarboxylation. Both drying systems showed a significant loss in total terpene concentration, yet freeze-drying has a higher metabolite retention compared to MAHD. These results may prove useful for future experiments investigating antioxidant activity and added value to cannabis and hops.

Sex, gender or occupational psychology: what matters most to preventing heat-related illnesses and improving outcomes for women in ground close combat?

Since the advent of women in ground close combat (WGCC) roles, the impact on women of the attendant risk of heat stress and heat illness has been considered. Much emphasis has been placed on sex differences in thermal physiology. This article considers the application of evidence of sex-associated thermoregulatory variation to the occupational and environmental setting of WGCC, and weighs the relative importance of physiological differences arising from biological sex, and behaviour associated with gender normatives. Quantifying the risk of heat illness to WGCC should draw on data from their real-world occupational context.

CPD in the remote environment: a role for practice-based small group learning

BACKGROUND

Continuous professional development (CPD) is recognised as essential and mandated by the Royal College of General Practitioners and other medical professional colleges. However, it can be difficult to maintain when deployed and remote from normal training and support structures. There is no literature directly discussing how military doctors in the deployed and remote environment maintain CPD and if practice-based small group learning (PBSGL) could be an appropriate tool to facilitate this in future.

AIM

To describe the CPD experience of medical officers (MOs) working for the Defence Medical Services (DMS) and assess if offering PBSGL would be welcomed and likely beneficial.

DESIGN AND SETTING

This is a quantitative survey of doctors working in primary care within the DMS.

METHOD

A questionnaire was designed to elicit opinions, current practice and previous experience of CPD within the deployed and firm base environments. It also aimed to elicit prior experience of and appetite for PBSGL as a solution. This was then distributed via email to MOs working for the DMS.

RESULTS

130 responses (25%) were received. 122 (96%) had heard of PBSGL, 56% had participated in PBSGL in the firm base. 60% agreed or strongly agreed PBSGL was an effective way to maintain CPD. 73% reported eLearning as a mode of maintaining CPD while deployed or working in a remote environment.

CONCLUSION

This study demonstrated that many general practitioners deployed to remote locations feel that CPD provision could be improved and that PBSGL is a potential solution.

Comparative compositional analysis of cassava brown streak disease resistant 4046 cassava and its non-transgenic parental cultivar

Compositional analysis is an important component of an integrated comparative approach to assessing the food and feed safety of new crops developed using biotechnology. As part of the safety assessment of cassava brown streak disease resistant 4046 cassava, a comprehensive assessment of proximates, minerals, amino acids, fatty acids, vitamins, anti-nutrients, and secondary metabolites was performed on leaf and storage root samples of 4046 cassava and its non-transgenic parental control, TME 204, collected from confined field trials in Kenya and Uganda over two successive cropping cycles. Among the 100 compositional components that were assessed in samples of 4046 and control TME 204 cassava roots (47 components) and leaves (53 components), there were no nutritionally relevant differences noted. Although there were statistically significant differences between the transgenic and control samples for some parameters, in most cases the magnitudes of these differences were small (<20%), and in every case where comparative literature data were available, the mean values for 4046 and control cassava samples were within the range of normal variation reported for the compositional component in question. Overall, no consistent patterns emerged to suggest that biologically meaningful adverse changes in the composition or nutritive value of the leaves or storage roots occurred as an unintended or unexpected consequence of the genetic modification resulting in 4046 cassava. The data presented here provide convincing evidence of the safety of 4046 cassava with respect to its biochemical composition for food and feed, and it could be considered as safe as its non-transgenic control.

0802 To Examine the Effect of Gabapentin Enacarbil in Primary Restless Legs Syndrome Patients Who are on Dopaminergic Agents and Exhibiting Augmentation

Introduction

Augmentation is defined as worsening of the symptoms of Restless Legs Syndrome after a brief period of initial improvement with dopaminergic agents resulting in either an earlier onset, increase in severity, quicker onset, spread to other body parts. The exact prevalence of this phenomenon is not known and in patients experiencing augmentation, it can pose a difficult diagnostic and therapeutic challenge to the clinician. In our study, we found extended-release gabapentin to be an effective intervention in patients experiencing dopaminergic augmentation

Methods

This is an open-label single-arm study done in patients exhibiting augmentation while on dopaminergic agents. Patients who were enrolled in the study were initiated on oral extended-release gabapentin(Horizont) 600 mg at 5 pm at the beginning of the study. At day 90, attempts were made to reduce or discontinue dopaminergic agents. International Restless Legs Syndrome-Rating Scale (IRLS) and Augmentation Severity Rating Scale(ASRS) were recorded at each visit.

Results

A total of 10 patients were enrolled in the study while only 8 patients completed it. Compared to the baseline (visit 2), there is a significant improvement in both the augmentation severity(p= 0.0131) and the IRLS (p=0.0497). Wilcoxon matched-pairs signed rank test was used for statistical analysis.

Conclusion

Extended-release Gabapentin is an effective treatment option in primary RLS patients experiencing augmentation secondary to dopaminergic medication usage.

Support

The study is funded and medication is provided by Arbor Pharmaceuticals.

The development and evaluation of a nationwide training program for oncology health professionals in the provision of genetic testing for ovarian cancer patients

BACKGROUND

BRCA1/2 mutation status has increasing relevance for ovarian cancer treatments, making traditional coordination of genetic testing by genetic services unsustainable. Consequently alternative models of genetic testing have been developed to improve testing at the initial diagnosis for all eligible women.

METHODS

A training module to enable mainstreamed genetic testing by oncology healthcare professionals was developed by genetic health professionals. Oncology healthcare professionals completed questionnaires before and 12 months post-training to assess perceived skills, competence and barriers to their coordinating genetic testing for women with high-grade non-mucinous epithelial ovarian cancer. Genetic health professionals were surveyed 12 months post-training to assess perceived barriers to implementation of mainstreaming.

RESULTS

185 oncology healthcare professionals were trained in 42 workshops at 35 Australasian hospitals. Of the 273 tests ordered by oncology healthcare professionals post-training, 241 (93.1%) met national testing guidelines. The number of tests ordered by genetic health professionals reduced significantly (z = 45.0, p = 0.008). Oncology healthcare professionals' perceived barriers to mainstreamed testing decreased from baseline to follow-up (t = 2.39, p = 0.023), particularly perceived skills, knowledge and attitudes. However, only 58% reported either 'always' or 'nearly always' having ordered BRCA testing for eligible patients at 12 months, suggesting oncology healthcare professionals' perceived barriers were not systematically addressed through training.

CONCLUSIONS

Oncology healthcare professionals have demonstrated a willingness to be involved in the provision of genetic testing in a mainstreaming model. If oncology services are to hold responsibility for coordinating genetic testing, their readiness will require understanding of barriers not addressed by training alone to inform future intervention design.

Heat illness during initial military training

INTRODUCTION

Exertional heat illness (EHI) is recognised as a significant problem for fit young individuals taking part in strenuous activity in temperate climates. The aim of this research was to relate episodes of reported EHI against known risk factors for heat illness and determine whether modification of the training programme had an effect on the number of cases reported. Publication was not possible when the work was originally conducted in 2000 because of barriers within Royal Military Academy Sandhurst (RMAS) at the time.

METHODS

A retrospective study examined the medical data for Officer Cadets in training at the RMAS for a 2-year period ending April 2000.

RESULTS

60 cases were initially reported as EHI, in 58 individuals. Using the following criteria; dizziness, collapse, reduced conscious level, headache, nausea, vomiting, elevated core (rectal) temperature and the results of urine and blood tests, 35 cases were diagnosed as EHI and 25 cases had other diagnoses recorded after investigation. Minority of cases (n=12) had an identifiable risk factor but the majority appeared to be fit young individuals who were susceptible to EHI in conditions where the rest of the population was unaffected.

DISCUSSION

Further work is planned to study individuals during strenuous activity events in the hope of accurately identifying those at risk and further reducing the incidence of EHI. EHI is common, case definition is poor, risk factors are not present in all individuals but modification of training programmes is effective.

Role of the pre-hospital treatment team on the UK military exercise SAIF SAREEA 3

The prehospital treatment team (PHTT) involves a small team working under the clinical supervision of a clinical lead. The clinical lead can be a general duties medical officer (Post Foundation Years Doctor), military nurse practitioner or more senior clinician. The team is mounted in vehicles appropriate to the environment they expect to operate in. A PHTT is closely located to the front line reducing transportation timelines from the point of wounding to more definitive care. The PHTT can provide medical support on the move or when time is available; a more permanent fully erected treatment facility can be established. Either configuration can provide both trauma and primary care. The size of the team allows for multiple trauma subteams enabling care to casualties that arrive simultaneously. The PHTT can move independently which could leave the team vulnerable as there is no integral force protection within the current structure. In such a small team, the right balance of medical and soldiering skills among team members is essential to success. Exercise SAIF SAREEA 3 represented a large-scale battlegroup exercise to the Middle East in the austere desert of Oman. This provided an ideal environment for employing the PHTT concept is a large deployed force undertaking dynamic activity.

National Prevalence of Disability and Clinical Accommodations in Medical Education

BACKGROUND

This study aimed to evaluate and report the national prevalence of disability across undergraduate medical education (UME) and examine differences in the category of disability, and accommodation practices between allopathic (MD)- and osteopathic (DO)-granting programs.

METHODS

Between May 20 and June 30, 2020, 75% of institutional representatives at eligible DO schools responded to a web-based survey. The survey assessed the aggregate prevalence of disabled DO students, prevalence of DO students by category of disability, and prevalence of accommodations granted. Descriptive statistics were used to summarize results. Using 2019 MD data, comparisons were made between MD and DO programs to calculate overall prevalence and differences in accommodation practices across undergraduate medical education.

RESULTS

DO-granting programs reported a disability prevalence of 4.27% of the total enrollment. Attention-deficit/hyperactivity disorder (ADHD), psychological disabilities, and chronic health disabilities were reported most frequently. DO-granting programs reported higher rates of ADHD than the MD-granting program. The national pooled prevalence of disability across MD- and DO-granting programs was 4.52%. MD-granting programs reported a higher number of students with disabilities and higher rates of psychological disabilities when compared with DO-granting programs. One hundred percent of DO students disclosing disability received some form of accommodation. General clinical accommodations were more frequently provided in MD-granting programs when compared to DO-granting programs.

CONCLUSIONS

This study provides the first comprehensive prevalence of US medical student disability and accommodations. Additionally, these data may serve as a benchmark for DO programs, with implications for curricular development, instructional planning and disability support, and resource allocation in medical education.

Family history of prostate cancer and age-related trend of testosterone levels among US males: NHANES 2003-2004

BACKGROUND

Studies have suggested that rapid age-related declines of testosterone (T) level may play a critical role in the development of prostate cancer (PCa), and family history of PCa is another well-established risk factor of PCa, which have been reported to be associated with androgen metabolism-related genes. However, few studies have ever investigated whether a family history of PCa influences the risk of PCa via regulating the age-related trend of T level among males over the life course.

OBJECTIVES

To examine the association between family history of PCa and age-related trend of T levels.

MATERIALS AND METHODS

We used National Health and Nutrition Examination Survey (NHANES) data from 2003 to 2004 (n = 322) to compare the age-specific T levels in males with a family history of PCa and those without.

RESULTS

We found that between two younger age groups (ages 20-39 and 40-59), there was a more pronounced drop-off in T levels among men with a family history of PCa compared to men without a family history.

DISCUSSION AND CONCLUSION

This preliminary analysis suggested that men with a family history of PCa may experience a sharper decline in T level over the life course as compared to males without a family history. However, no conclusions can be made due to small sample sizes. Further longitudinal studies with large sample sizes are needed.

Cytokine responses to exercise and activity in patients with chronic fatigue syndrome: case-control study

Chronic fatigue syndrome (CFS) is characterized by fatigue after exertion. A systematic review suggested that transforming growth factor (TGF)-β concentrations are often elevated in cases of CFS when compared to healthy controls. This study attempted to replicate this finding and investigate whether post-exertional symptoms were associated with altered cytokine protein concentrations and their RNA in CFS patients. Twenty-four patients fulfilling Centers for Disease Control criteria for CFS, but with no comorbid psychiatric disorders, were recruited from two CFS clinics in London, UK. Twenty-one healthy, sedentary controls were matched by gender, age and other variables. Circulating proteins and RNA were measured for TGF-β, tumour necrosis factor (TNF), interleukin (IL)-8, IL-6 and IL-1β. We measured six further cytokine protein concentrations (IL-2, IL-4, IL-5, IL-10, IL-12p70, and interferon (IFN)-γ). Measures were taken at rest, and before and after both commuting and aerobic exercise. CFS cases had higher TGF-β protein levels compared to controls at rest (median (quartiles) = 43·9 (19·2, 61·8) versus 18·9 (16·1, 30·0) ng/ml) (P = 0·003), and consistently so over a 9-day period. However, this was a spurious finding due to variation between different assay batches. There were no differences between groups in changes to TGF-β protein concentrations after either commuting or exercise. All other cytokine protein and RNA levels were similar between cases and controls. Post-exertional symptoms and perceived effort were not associated with any increased cytokines. We were unable to replicate previously found elevations in circulating cytokine concentrations, suggesting that elevated circulating cytokines are not important in the pathophysiology of CFS.

Is the support that dental registrants in difficulty receive from postgraduate dental teams and other sources adequate?

Objective The aim of this research was to investigate the views of dental registrants in difficulty (DRiDS) on the support they received from postgraduate dental teams (PgDT) in Health Education England (HEE) and other sources. These data were complemented by the views of those appointed from the PgDT to support them on the service they provide.Method Qualitative data were collected by recording one-to-one semi structured telephone interviews, lasting approximately 30 minutes, with registrants in difficulty and supporters purposefully sampled from across England and Wales. Recordings were transcribed and the interview data analysed for recurring discourses and themes using thematic framework analysis.Setting and subjects All regional leads for DRiDs services in PgDT across the UK were asked to invite the DRiDs they were in contact with and the supporters they had appointed to contact the research team. Attempts were made to contact all who returned consent forms and six DRiDs and 11 supporters were eventually interviewed.Results Overall the DRiDs thought that the PgDT were very helpful. They were in many cases the only source of expert support and advice, particularly with regard to developing a personal development plan and collecting evidence about their practice to present to the regulator. There was a good match between the qualities that DRiDs wanted their supporters to have and the strengths supporters felt they brought to the role. The DRiDs had mixed views about the support provided by their indemnifiers and could not identify any other organisations that provided support once conditions had been imposed. Some had the support of peers; but both DRiDs and supporters felt there was a need for further support in addition to the educational support provided by PgDT and legal support provided by the indemnifier.Conclusion The DRiDS regarded the PgDT as their primary source of support and, in general, were very satisfied with the character and competence of the service.

Adenomatous-Dominant Benign Prostatic Hyperplasia (AdBPH) as a Predictor for Clinical Success Following Prostate Artery Embolization: An Age-Matched Case-Control Study

PURPOSE

To investigate the clinical impact of performing prostate artery embolization (PAE) on patients with adenomatous-dominant benign prostatic hyperplasia (AdBPH).

MATERIALS AND METHODS

Twelve patients from the ongoing proSTatic aRtery EmbolizAtion for the treatMent of benign prostatic hyperplasia (STREAM) trial were identified as having AdBPH; defined as two or more adenomas within the central gland of ≥1 cm diameter on multi-parametric MRI (MP-MRI). These patients were age-matched with patients from the STREAM cohort, without AdBPH. Patients were followed up with repeat MP-MRI at 3 months and 1 year. International prostate symptom score (IPSS), international index for erectile function (IIEF), and quality of life assessment from the IPSS and EQ-5D-5S questionnaires were recorded pre-PAE and at 6 weeks, 3 months, and 1 year.

RESULTS

The mean age of patients was 68 (61-76). All patients had PAE as a day-case procedure. The technical success in the cohort was 23/24 (96%). There was a significant reduction in prostate volume following embolization with a median reduction of 34% (30-55) in the AdBPH group, compared to a mean volume reduction of 22% (9-44) in the non-AdBPH group (p = 0.04). There was a significant reduction in IPSS in the AdBPH group following PAE when compared with the control group [AdBPH median IPSS 8 (3-15) vs. non-AdBPH median IPSS 13 (8-18), p = 0.01]. IPSS QOL scores significantly improved in the AdBPH group (p = 0.007). There was no deterioration in sexual function in either group post-PAE.

CONCLUSIONS

This is the first time that AdBPH has been identified as being a predictor of clinical success following PAE.

Supporting dental registrants in difficulty: the service provided by postgraduate dental education teams

The number of dental registrants in difficulty (DRiDs) has increased significantly in recent years and the General Dental Council or National Health Service organisations tasked with the management of dental services will, if appropriate, instruct the registrant to contact postgraduate dental teams (PgDT) based in regional offices of Health Education England and equivalent postgraduate deaneries in Wales and Scotland for assistance in meeting their conditions for continued registration. We surveyed DRiDs Leads within the PgDT with a view to understanding the current development of this important service. Results revealed that these managers had considerable relevant previous experience which underpinned their responsibility for DRiDs. Their responses indicated that there were notable differences between PgDT in the number of DRiDs seeking their help and that the development of the service and the resources deployed to help DRIDs also differed significantly. Those responsible were generally happy with the service they were providing and all were able to see DRiDs for an initial interview within four weeks of being contacted. However, weaknesses were identified such as insufficient time to support individual registrants, lack of consistent process across PgDT teams and a need for clinical training facilities.

Galam's bottom-up hierarchical system and public debate model revisited

This paper is concerned with the bottom-up hierarchical system and public debate model proposed by Galam (2008), as well as a spatial version of the public debate model. In all three models, there is a population of individuals who are characterized by one of two competing opinions, say opinion −1 and opinion +1. This population is further divided into groups of common size s. In the bottom-up hierarchical system, each group elects a representative candidate, whereas in the other two models, all the members of each group discuss at random times until they reach a consensus. At each election/discussion, the winning opinion is chosen according to Galam's majority rule: the opinion with the majority of representatives wins when there is a strict majority, while one opinion, say opinion −1, is chosen by default in the case of a tie. For the public debate models we also consider the following natural updating rule that we call proportional rule: the winning opinion is chosen at random with a probability equal to the fraction of its supporters in the group. The three models differ in term of their population structure: in the bottom-up hierarchical system, individuals are located on a finite regular tree, in the nonspatial public debate model, they are located on a complete graph, and in the spatial public debate model, they are located on the d-dimensional regular lattice. For the bottom-up hierarchical system and nonspatial public debate model, Galam studied the probability that a given opinion wins under the majority rule and, assuming that individuals' opinions are initially independent, making the initial number of supporters of a given opinion a binomial random variable. The first objective of this paper is to revisit Galam's result, assuming that the initial number of individuals in favor of a given opinion is a fixed deterministic number. Our analysis reveals phase transitions that are sharper under our assumption than under Galam's assumption, particularly with small population size. The second objective is to determine whether both opinions can coexist at equilibrium for the spatial public debate model under the proportional rule, which depends on the spatial dimension.