Experimental comparison of E-band BDFA and Raman amplifier performance over 50 km G.652.D fiber using 30 GBaud DP-16-QAM and DP-64-QAM signals.

We compare the performance of three optical amplifiers in the E-band: a bismuth-doped fiber amplifier (BDFA), a distributed Raman amplifier, and a discrete Raman amplifier (RA). Data transmission performance of 30 GBaud DP-16-QAM and DP-64-QAM signals transmitted over 50 km of G.652.D fiber is compared in terms of achieved signal-to-noise (SNR). In this specific case of relatively short distance, single-span transmission, the BDFA outperforms the distributed and discrete Raman amplifiers due to the impact of fiber nonlinear penalties at high input signal powers.

Capacity Planning of Virtual Wards for Frail and Elderly Patients.

This paper investigates the planning of virtual ward (VW) capacity including the remote monitoring of frail and elderly patients. The main objective is to optimize VW hub locations across a region in the United Kingdom. Furthermore, assigning the optimal number of clinicians to different regions needs to be considered. We develop a mathematical model that minimizes the setup and travel costs of VW hubs and staff. Our experimental analysis evaluates different levels of demand considering postcode areas within different Trusts, also known as Health Boards, in the National Health Service (NHS). Furthermore, our experiments provide insights into how many hub locations should be deployed and staffed. This can be used to individually find the number of remote monitors and clinicians for each facility as well as the system overall.

Time to complete contemporary dental procedures - estimates from a cross-sectional survey of the dental team.

BACKGROUND: There are few contemporary studies on the time taken to complete dental procedures, those most heavily relied on in the United Kingdom date back to 1999. OBJECTIVES: This work aimed to establish how long members of the dental team took to complete specific dental procedures, relevant to their scope of practice. METHODS: Data were collected via a purposive sample of 96 dentists, dental hygienists/therapists and dental nurses. Via an online survey, participants were asked to state the mean, minimum and maximum time they estimated that they took to complete individual dental procedures. RESULTS: The mean time taken to complete procedures common to both dentists and dental hygienists/therapists ranged from 3.7 to 4 min respectively for clinical note reading prior to seeing patients to 30.1 and 28 min to undertake root surface debridement. There were no significant differences between the time taken by dentists and dental hygienists/therapists to treat adult patients. However, in all but one procedure, dental hygienists/therapists reported taking longer (p = 0.04) to treat child patients. CONCLUSIONS: The data provided here represent an up to date assessment of the time taken to complete specific tasks by different members of the dental team. These data will be of value to service planners and commissioners interested in evolving a dental care system that employs a greater degree of skill-mix and preventively oriented care.

Direct oral anticoagulants or vitamin K antagonists in emergencies: comparison of management in an observational study.

Background: Restoring hemostasis in patients on oral anticoagulants presenting with major hemorrhage (MH) or before surgical intervention has changed, with the replacement of vitamin K antagonist (VKA) with direct oral anticoagulants (DOACs). Objectives: To observe the difference in urgent hemostatic management between patients on VKA and those on DOACs. Methods: A multicenter observational study evaluated the variation in laboratory testing, hemostatic management, mortality, and hospital length of stay (LOS) in patients on VKA or DOACs presenting with MH or urgent hemostatic restoration. Results: Of the 1194 patients analyzed, 783 had MH (61% VKA) and 411 required urgent hemostatic restoration before surgery (56% VKA). Compared to the international normalized ratio (97.6%), plasma DOAC levels were measured less frequently (<45%), and the time taken from admission for the coagulation sample to reach the laboratory varied widely (median, 52.3 minutes; IQR, 24.8-206.7). No significant plasma DOAC level (<50 ng/mL) was found in up to 19% of patients. There was a poor relationship between plasma DOAC level and the usage of a hemostatic agent. When compared with patients receiving VKA (96.5%) or dabigatran (93.7%), fewer patients prescribed a factor Xa inhibitor (75.5%) received a prohemostatic reversal agent. The overall 30-day mortality for MH (mean: 17.8%) and length of stay (LOS) (median: 8.7 days) was similar between VKA and DOAC patients. Conclusion: In DOAC patients, when compared to those receiving VKA, plasma DOAC levels were measured less frequently than the international normalized ratio and had a poor relationship with administering a hemostatic reversal agent. In addition, following MH, mortality and LOS were similar between VKA and DOAC patients.

Understanding the Impact of Social Networks on the Spread of Obesity.

Previous research has highlighted the significant role social networks play in the spread of non-communicable chronic diseases. In our research, we seek to explore the impact of these networks in more detail and gain insight into the mechanisms that drive this. We use obesity as a case study. To achieve this, we develop a generalisable hybrid simulation and optimisation approach aimed at gaining qualitative and quantitative insights into the effect of social networks on the spread of obesity. Our simulation model has two components. Firstly, an agent-based component mimics the dynamic structure of the social network within which individuals are situated. Secondly, a system dynamics component replicates the relevant behaviours of those individuals. The parameters from the combined model are refined and optimised using longitudinal data from the United Kingdom. The simulation produces projections of Body Mass Index broken down by different age groups and gender over a 10-year period. These projections are used to explore a range of scenarios in a computational study designed to address our research aims. The study reveals that, for the youngest population sub-groups, the network acts to magnify the impact of external and social factors on changes in obesity, whereas, for older sub-groups, the network mitigates the impact of these factors. The magnitude of that impact is inversely correlated with age. Our approach can be used by public health decision makers as well as managers in adult weight management services to enhance initiatives and strategies intended to reduce obesity. Our approach is generalisable to understand the impact of social networks on similar non-communicable diseases.

Modelling lung cancer diagnostic pathways using discrete event simulation.

The United Kingdom has one of the poorest lung cancer survival rates in Europe. In this study, to help design and evaluate a single lung cancer pathway (SCP) for Wales, existing diagnostic pathways and processes have been mapped and then modelled with a discrete event simulation. The validated models have been used to provide key performance indicators and to examine different diagnostic testing strategies. Under the current diagnostic pathways, the mean time to treatment was 72 days for surgery patients, 56 days for chemotherapy patients, and 61 days for radiotherapy patients. Our research demonstrated that by ensuring that the patient attends their first outpatient appointment within 7 days and streamlining the diagnostic tests would have the potential to remove approximately 11 days from the current lung cancer pathway resulting in a 21% increase in patients receiving treatment within the Welsh Government set target of 62 days.

Performance evaluation of discrete Raman amplifiers in coherent transmission systems.

We evaluate the performance penalty due to discrete Raman amplifier (DRA) in a long haul WDM transmission system. The investigation was primarily performed to study the impact of the accumulated nonlinear noise due to fibre chromatic dispersion and nonlinear coefficient(γ). Nonlinear fibres such as inverse dispersion fibre (IDF), dispersion compensation fibre (DCF) and a development fibre known as the Corning Raman fibre (CRF) with the opposite sign of CD to the other two, were taken as the gain fibre in the DRA stage of the long-haul transmission setup. To study the performance penalty with these Raman gain fibres a 30 GBaud 120 Gb/s DP-QPSK channel @1550 nm was combined with 9 spectrally shaped 50 GHz amplified spontaneous emission (ASE) channels for transmission over a recirculation loop with a per loop length of 63 km single mode fibre (SMF). Our modelling and experimental results show that a fibre with positive dispersion >10ps/nm/km and a nonlinear coefficient of ∼ 4W-1km-1 is a good choice of gain fibre for DRA-assisted coherent transmission system.

E-, S-, C- and L-band coherent transmission with a multistage discrete Raman amplifier.

We report for the first time an ultra-wideband coherent (UWB) WDM transmission over a 70 km standard single mode fibre (SSMF) solely using a multistage discrete Raman amplifier (DRA) over the E-, S-, C- and L-bands of the optical window. The amplifier is based on a split-combine approach of spectral bands enabling signal amplification from 1410-1605 nm over an optical bandwidth of 195 nm (25.8 THz). The proposed amplifier was characterized with 143 channelized amplified spontaneous emission (ASE) dummy channels in the S-, C- and L-bands and 4 laser sources in the E-band (1410-1605 nm). The amplification results show an average gain of 14 dB and a maximum noise figure (NF) of 7.5 dB over the entire bandwidth. Coherent transmission with the proposed amplifier was performed using a 30 Gbaud PM-16-QAM channel coupled with the ASE channels over a 70 km SMF. The ultra-wideband transmission using the tailored multistage DRA shows transmission bandwidth of 195 nm with a maximum Q2 penalty of ∼4 dB in E- and S-band, and ∼2 dB in C- and L-band.

Ultra-wideband discrete Raman amplifier optimization for single-span S-C-L-band coherent transmission systems.

We experimentally compare the performance of two key ultra-wideband discrete Raman amplifier structures, a cascaded dual-stage structure and an in-parallel dual-band structure, in fully loaded S-C-L band coherent transmission systems over 70 km of single-mode fiber. Our results show that dual-band discrete Raman amplifier with minimized backreflections can effectively avoid unstable random distributed feedback lasing, reduce the noise figure, and therefore improve the transmission performance for signals at shorter wavelengths, versus the cascaded dual-stage structure. The average noise figure for S-band signals is 6.8 dB and 7.2 dB for the dual-band structure and cascaded dual-stage structure, respectively, while the average S-band Q2 factor is similarly improved by 0.6 dB. Moreover, the cascaded dual-stage discrete Raman amplifier requires guard bands around the 1485-nm and 1508-nm pumps as the signal and pump wavelengths overlap, which results in a bandwidth loss of ∼10 nm and reduces the potential net data throughput to 28.6 Tb/s for 30-GBaud DP-16QAM signals. However, the dual-band structure can utilize the bandwidth more effectively, which leads to a higher estimated net data throughput of 31.2 Tb/s.

30-GBaud DP 16-QAM transmission in the E-band enabled by bismuth-doped fiber amplifiers.

We report the transmission of five 30-GBaud dual polarization 16-QAM signals over 160 km of standard single-mode fiber in the E-band (1410-1460 nm). The transmission line consists of two 80-km spans and three independent bismuth-doped fiber amplifiers. The developed amplifiers feature a maximum gain of 27.3 dB, 33.8 dB, and 28.3 dB with a minimum noise figure of 4.8 dB, 4.7 dB, and 5.3 dB, respectively. The maximum signal Q2 factor penalty is 4.5 dB, and the overall performance of the system is above the pre-forward-error-correction (FEC) threshold for a 10-15 post-FEC bit error rate. To the best of our knowledge, this is the record experimentally demonstrated transmission length for a coherent detection signal in the E-band.

Routine CTA screening identifies blunt cerebrovascular injuries missed by clinical risk factors.

Objectives: Current guidelines for screening for blunt cerebrovascular injury (BCVI) are commonly based on the expanded Denver criteria, a set of risk factors that identifies patients who require CT-angiographic (CTA) screening for these injuries. Based on previously published data from our center, we have adopted a more liberal screening guideline than those outlined in the expanded Denver criteria. This entails routine CTA of the neck for all blunt trauma patients already undergoing CT of the cervical spine and/or CTA of the chest. The aim of this study was to analyze the incidence of patients with BCVI who did not meet any of the risk factors included in the expanded Denver criteria. Methods: A retrospective review of all patients diagnosed with BCVI between June 2014 and December 2019 at a Level I Trauma Center were identified from the trauma registry. Medical records were reviewed for the presence or absence of risk factors as outlined in the expanded Denver criteria. Demographic data, time to CTA and treatment, BCVI grade, Glasgow Coma Scale and Injury Severity Score were collected. Results: During the study period, 17 054 blunt trauma patients were evaluated, and 29% (4923) underwent CTA of the neck to screen for BCVI. 191 BCVIs were identified in 160 patients (0.94% of all blunt trauma patients, 3.25% of patients screened with CTA). 16% (25 of 160) of patients with BCVI had none of the risk factors outlined in the Denver criteria. Conclusion: Our findings indicate that reliance on the expanded Denver criteria alone for BCVI screening will result in missed injuries. We recommend CTA screening in all patients with blunt trauma undergoing CT of the cervical spine and/or CTA of the chest to minimize this risk. Level of evidence: Level III, therapeutic/care management.

Modelling changes in healthcare demand through geographic data extrapolation.

Stay Well Plans are a new programme of care offered to frail and elderly people in Newport. In 2016 a roll out the programme to be offered in all five counties serviced by Aneurin Bevan University Health Board was planned. This paper presents the data analysis and modelling used to determine the programme's effects on the demand of the wider system, and the effects of a Gwent-wide roll out. We extrapolate information from data from a geographical subset of the model domain to a larger geographical area, adjusting for population sizes, deprivation, and distances to healthcare facilities. These parametrise a Markov model and Monte Carlo simulation to predict changes in demand due to different levels of roll out. We conclude that a programme roll out may result in a large reduction on demand at residential care, however at the expense of an increase in demand at community care services.

The changing use of anticoagulants in New Zealand.

AIMS: To assess the change in the use of oral anticoagulants in New Zealand over 10 years since the introduction of dabigatran and rivaroxaban. METHODS: Data were collected from the National Pharmaceutical database from January 2011 to March 2021. Seven and a half million prescriptions for oral anticoagulants were analysed. RESULTS: The total number of people taking oral anticoagulants increased from 46,000 in July 2011 to 105,000 by March 2021. The growth was predominantly from the increased use of direct oral anticoagulants (DOACs). Initially, dabigatran was the only funded DOAC in New Zealand; approximately 50,000 people were taking this medication by August 2018, when rivaroxaban was introduced. Subsequent growth has predominantly been from rivaroxaban, with 23,000 users by March 2021. Warfarin use has dropped by 50% over the last 10 years. CONCLUSIONS: The introduction of the DOACs was expected to reduce the use of warfarin. However, the rapid rise in DOAC use was not predicted. The increase is most likely in patients with atrial fibrillation with the positive benefit of reducing the incidence of embolic stroke. However, having a high proportion of the elderly population (15% of people over 75-years) on anticoagulants has implications for the health sector, making hospital admissions and surgery more complex.

The development and application of a chairside oral health risk and need stratification tool in general dental services.

OBJECTIVE: To describe the development and application of the Assessment of Clinical Oral Risks and Needs (ACORN) stratification tool based on a traffic light system in National Health Service (NHS) general dental services (GDS) Wales, UK. MATERIALS AND METHODS: This was a secondary analysis of routinely-collected dental care data. All courses of treatment provided in dental practices participating in NHS GDS Reform Programme between July 2018 and September 2019, in which an ACORN assessment and age were recorded were included in the analysis. RESULTS: A total of 236,490 subjects contributed 339,933 courses of treatment during the study period. 'Amber' and 'red' ACORN outcomes were associated with more courses of treatment per annum than 'green' outcomes. Outcomes indicating an increased risk of decay or other dental problems were associated with a greater likelihood of several operative treatment items. Patients at greater risk of poor periodontal health were more likely to receive extractions and dentures than low-risk patients. Patients were most likely to either remain in the same ACORN outcome categories or move to a healthier state between assessments. CONCLUSION: More research is required to understand the utility of the ACORN tool in risk communication and behaviour change.

Emergency services utilization in Jakarta (Indonesia): a cross-sectional study of patients attending hospital emergency departments.

BACKGROUND: Pre-hospital and emergency services in Indonesia are still developing. Despite recent improvements in the Indonesian healthcare system, issues with the provision of pre-hospital and emergency services persist. The demand for pre-hospital and emergency services has not been the subject of previous research and, therefore, has not been fully understood. Our research explored the utilization of emergency medical services by patients attending hospital emergency departments in Jakarta, Indonesia. METHODS: The study used a cross-sectional survey design involving five general hospitals (four government-funded and one private). Each patient's demographic profile, medical conditions, time to treatment, and mode of transport to reach the hospital were analysed using descriptive statistics. RESULTS: A total of 1964 (62%) patients were surveyed. The median age of patients was 44 years with an interquartile range (IQR) of 26 to 58 years. Life-threatening conditions such as trauma and cardiovascular disease were found in 8.6 and 6.6% of patients, respectively. The majority of patients with trauma travelled to the hospital using a motorcycle or car (59.8%). An ambulance was used by only 9.3% of all patients and 38% of patients reported that they were not aware of the availability of ambulances. Ambulance response time was longer as compared to other modes of transportation (median: 24 minutes and IQR: 12 to 54 minutes). The longest time to treatment was experienced by patients with neurological disease, with a median time of 120 minutes (IQR: 78 to 270 minutes). Patients who used ambulances incurred higher costs as compared to those patients who did not use ambulances. CONCLUSION: The low utilization of emergency ambulances in Jakarta could be contributed to patients' lack of awareness of medical symptoms and the existence of ambulance services, and patients' disinclination to use ambulances due to high costs and long response times. The emergency ambulance services can be improved by increasing population awareness on symptoms that warrant the use of ambulances and reducing the cost burden related to ambulance use.

Modeling disease progression and treatment pathways for depression jointly using agent based modeling and system dynamics.

Introduction: Depression is a common mental health condition that affects millions of people worldwide. Care pathways for depression are complex and the demand across different parts of the healthcare system is often uncertain and not entirely understood. Clinical progression with depression can be equally complex and relates to whether or not a patient is seeking care, the care pathway they are on, and the ability for timely access to healthcare services. Considering both pathways and progression for depression are however rarely studied together in the literature. Methods: This paper presents a hybrid simulation modeling framework that is uniquely able to capture both disease progression, using Agent Based Modeling, and related care pathways, using a System Dynamics. The two simulation paradigms within the framework are connected to run synchronously to investigate the impact of depression progression on healthcare services and, conversely, how any limitations in access to services may impact clinical progression. The use of the developed framework is illustrated by parametrising it with published clinical data and local service level data from Wales, UK. Results and discussion: The framework is able to quantify demand, service capacities and costs across all care pathways for a range of different scenarios. These include those for varying service coverage and provision, such as the cost-effectiveness of treating patients more quickly in community settings to reduce patient progression to more severe states of depression, and thus reducing the costs and utilization of more expensive specialist settings.

Constructing operating theatre schedules using partitioned graph colouring techniques.

In hospitals, scheduled operations can often be cancelled in large numbers due to the unavailability of beds for post-operation recovery. Operating theatre scheduling is known to be an N P -hard optimisation problem. Previous studies have shown that the correct scheduling of surgical procedures can have a positive impact on the availability of beds in hospital wards, thereby allowing a reduction in number of elective operation cancellations. This study proposes an exact technique based on the partitioned graph colouring problem for constructing optimal master surgery schedules, with the goal of minimising the number of cancellations. The resultant schedules are then simulated in order to measure how well they cope with the stochastic nature of patient arrivals. Our results show that the utilisation of post-operative beds can be increased, whilst the number of cancellations can be decreased, which may ultimately lead to greater patient throughput and reduced waiting times. A scenario-based model has also been employed to integrate the stochastic-nature associated with the bed requirements into the optimisation process. The results indicate that the proposed model can lead to more robust solutions.

Raman Amplification Optimization in Short-Reach High Data Rate Coherent Transmission Systems.

We compared the transmission performances of 600 Gbit/s PM-64QAM WDM signals over 75.6 km of single-mode fibre (SMF) using EDFA, discrete Raman, hybrid Raman/EDFA, and first-order or second-order (dual-order) distributed Raman amplifiers. Our numerical simulations and experimental results showed that the simple first-order distributed Raman scheme with backward pumping delivered the best transmission performance among all the schemes, notably better than the expected second-order Raman scheme, which gave a flatter signal power variation along the fibre. Using the first-order backward Raman pumping scheme demonstrated a better balance between the ASE noise and fibre nonlinearity and gave an optimal transmission performance over a relatively short distance of 75 km SMF.

RIN induced penalties in G.654.E and G.652.D based distributed Raman amplifiers for coherent transmission systems.

Relative intensity noise (RIN) induced penalties were experimentally measured in distributed Raman amplifiers (DRAs) for G.654.E and G.652.D fibres with forward, backward and bidirectional pumping configurations. The measured signal RIN using the G.654.E fibre was ∼3.5 dB and ∼2 dB lower than the G.652.D fibre with forward (FW) pump configuration for PM-QPSK and PM-8QAM signals, with single span transmission showing a Q-factor improvement of ∼3 dB and ∼2.5 dB for G.654.E over G.652.D fibres. The performance penalty in a long haul coherent system was evaluated for 28 GBaud PM-QPSK signals using a recirculation loop for backward and bidirectional distributed Raman amplifiers. Our experimental results demonstrate an additional transmission distance of more than 1000 km for G.654.E over its counterpart G.652.D assuming a HD-FEC limit of 8.5 dB.

Needs-led human resource planning for Sierra Leone in support of oral health.

BACKGROUND: In Sierra Leone (SL), a low-income country in West Africa, dental care is very limited, largely private, and with services focused in the capital Freetown. There is no formal dental education. Ten dentists supported by a similar number of dental care professionals (DCPs) serve a population of over 7.5 million people. The objective of this research was to estimate needs-led requirements for dental care and human resources for oral health to inform capacity building, based on a national survey of oral health in SL. METHODS: A dedicated operational research (OR) decision tool was constructed in Microsoft Excel to support this project. First, total treatment needs were estimated from our national epidemiological survey data for three key ages (6, 12 and 15 years), collected using the 'International Caries Classification and Management System (ICCMS)' tool. Second, oral health needs were extrapolated to whole population levels for each year-group, based on census demographic data. Third, full time equivalent (FTE) workforce capacity needs were estimated for mid-level providers in the form of Dental Therapists (DTs) and non-dental personnel based on current oral disease management approaches and clinical timings for treatment procedures. Fourth, informed by an expert panel, three oral disease management scenarios were explored for the national population: (1) Conventional care (CC): comprising oral health promotion (including prevention), restorations and tooth extraction; (2) Surgical and Preventive care (S5&6P and S6P): comprising oral health promotion (inc. prevention) and tooth extraction (D5 and D6 together, & at D6 level only); and (3) Prevention only (P): consisting of oral health promotion (inc. prevention). Fifth, the findings were extrapolated to the whole population based on demography, assuming similar levels of treatment need. RESULTS: To meet the needs of a single year-group of childrens' needs, an average of 163 DTs (range: 133-188) would be required to deliver Conventional care (CC); 39 DTs (range: 30-45) to deliver basic Surgical and Preventive care (S6P); 54 DTs for more extended Surgical and Preventive care (S5&6P) (range 38-68); and 27 DTs (range: 25-32) to deliver Prevention only (P). When scaled up to the total population, an estimated 6,147 DTs (range: 5,565-6,870) would be required to deliver Conventional care (CC); 1,413 DTs (range: 1255-1438 DTs) to deliver basic Surgical and Preventive care (S6P); 2,000 DTs (range 1590-2236) for more extended Surgical and Preventive care (S5&6P) (range 1590-2236); and 1,028 DTs to deliver Prevention only (P) (range: 1016-1046). Furthermore, if oral health promotion activities, including individualised prevention, could be delivered by non-dental personnel, then the remaining surgical care could be delivered by 385 DTs (range: 251-488) for the S6P scenario which was deemed as the minimum basic baseline service involving extracting all teeth with extensive caries into dentine. More realistically, 972 DTs (range: 586-1179) would be needed for the S5&6P scenario in which all teeth with distinctive and extensive caries into dentine are extracted. CONCLUSION: The study demonstrates the huge dental workforce needs required to deliver even minimal oral health care to the Sierra Leone population. The gap between the current workforce and the oral health needs of the population is stark and requires urgent action. The study also demonstrates the potential for contemporary epidemiological tools to predict dental treatment needs and inform workforce capacity building in a low-income country, exploring a range of solutions involving mid-level providers and non-dental personnel.