Exploring older care recipients' sleep status as a predictor for informal carer distress: evidence from New Zealand's interRAI home care assessment data.

OBJECTIVES: Understanding factors affecting informal carers' well-being is important to support healthy ageing at home. Sleep disturbances of care recipients are increasingly recognised as affecting the well-being of both parties. This research assesses the relationship between indicators of care recipients' sleep status and carer distress, as well as carer distress with subsequent admission to residential aged care, using prospectively collected Home Care International Residential Assessment Instrument (interRAI-HC) assessment data. PARTICIPANTS: Data were sourced from 127 832 assessments conducted between 2012 and 2019 for people aged 55 years or older who had support from at least one informal carer. The majority (59.4%) of care recipients were female and 59.1% were defined as having cognitive impairment or dementia (CIoD). SETTING: New Zealand. DESIGN: Logistic regression modelling was used to assess the independent relationships between indicators of care recipients' sleep status (difficulty sleeping and fatigue) and primary caregivers' distress (feeling overwhelmed or distressed). Kaplan meier curves illustrated the subsequent relationship between caregiver distress and care recipients' transitions to aged residential care. RESULTS: Care recipients' sleeping difficulty (32.4%) and moderate-severe fatigue (46.6%) were independently associated with caregiver distress after controlling for key demographic and health factors included in the assessment. Distress was reported by 39.9% of informal caregivers and was three times more likely among those supporting someone with a CIoD. Caregiver distress was significantly associated with care recipients' earlier admission into aged residential care. CONCLUSIONS: Indicators of sleep disturbance among care recipients are associated with increased likelihood of carer distress. This has implications for managing the overall home-care situation and long-term care needs, as well as the well-being of both parties. Findings will inform research and development of measures, services and interventions to improve the sleep and waking health of older people, including those with CIoD and family caregivers.

Acute assessment services for patient flow assistance in hospital emergency departments.

BACKGROUND: Emergency departments (EDs) are facing serious and significant issues in the delivery of effective and efficient care to patients. Acute assessment services have been implemented at many hospitals internationally to assist in maintaining patient flow for identified groups of patients attending the ED. Identifying the risks and benefits, and optimal configurations of these services may be beneficial to those wishing to utilise an acute assessment service to improve patient flow. OBJECTIVES: To assess the effects of acute assessment services on patient flow following attendance at a hospital ED. SEARCH METHODS: We searched MEDLINE, CENTRAL, Embase and two trials registers on 24 September 2022 to identify studies. No restrictions were imposed on publication year, publication type, or publication language. SELECTION CRITERIA: Studies eligible for inclusion were randomised trials and cluster-randomised trials with at least two intervention and two control sites. Participants were adults (as defined by study authors) receiving care either in the ED or the acute assessment service, where both were based in the hospital setting. The comparison was hospital-based acute assessment services with usual, ED-only care. The outcomes of this review were mortality at time point closest to 30 days, length of stay in the service (in minutes), and waiting time to see a doctor (in minutes). DATA COLLECTION AND ANALYSIS: We followed the standard procedures of Cochrane Effective Practice and Organisation of Care for this review (https://epoc.cochrane.org/resources). MAIN RESULTS: We identified a total of 5754 records in the search. Following assessment of 3609 de-duplicated records, none were found to be eligible for inclusion in this review. AUTHORS' CONCLUSIONS: At present there are no randomised controlled trials exploring the effects of acute assessment services on patient flow in hospital-based emergency departments compared to usual, ED-only care.

International medical tourism of US cancer patients for alternative cancer treatments: Financial, demographic, and clinical profiles of online crowdfunding campaigns.

BACKGROUND: Previous research has found that individuals may travel outside their home countries in pursuit of alternative cancer therapies (ACT). The goal of this study is to compare individuals in the United States who propose plans for travel abroad for ACT, compared with individuals who seek ACT domestically. METHODS: Clinical and treatment data were extracted from campaign descriptions of 615 GoFundMe® campaigns fundraising for individuals in the United States seeking ACT between 2011 and 2019. We examined treatment modalities, treatment location, fundraising metrics, and online engagement within campaign profiles. Clinical and demographic differences between those who proposed international travel and those who sought ACT domestically were examined using two-sided Fisher's exact tests. Differences in financial and social engagement data were examined using two-sided Mann-Whitney tests. RESULTS: Of the total 615 campaigns, 237 (38.5%) mentioned plans to travel internationally for ACT, with the majority (81.9%) pursuing travel to Mexico. Campaigns that proposed international treatment requested more money ($35,000 vs. $22,650, p < 0.001), raised more money ($7833 vs. $5035, p < 0.001), had more donors (57 vs. 45, p = 0.02), and were shared more times (377 vs. 290.5, p = 0.008) compared to campaigns that did not. The median financial shortfall was greater for campaigns pursuing treatments internationally (-$22,640 vs. -$13,436, p < 0.003). CONCLUSIONS: Campaigns proposing international travel for ACT requested and received more money, were shared more online, and had more donors. However, there was significantly more unmet financial need among this group, highlighting potential financial toxicity on patients and families.

Improved overall survival over time in advanced stage mycosis fungoides: a cross-sectional study.

Mycosis Fungoides (MF) is a rare T-cell lymphoma and evidence on treatment practices, and outcomes are limited. We evaluated changes in practice patterns and corresponding effects on overall survival (OS) in MF using a cross-sectional study of patients diagnosed with MF from 2004 to 2016 in the National Cancer Database. Outcomes evaluated included patterns of care and OS across treatment eras. We found factors associated with chemotherapy use included male gender, treatment from 2004 to 2010 and stage III-IV disease. Factors associated with radiotherapy receipt included stage I-II disease, nonacademic treatment centers, male gender, non-black race, and Medicare status. Immunotherapy use was associated with treatment from 2004 to 2010 and stage III-IV disease. After propensity score matching, there was no OS difference among patients with stage I-II disease between 2004-2010 and 2011-2016. However, amongst patients with stage III-IV disease, OS was significantly improved in those treated from 2011 to 2016.

Refusal of Local Therapy in Esophageal Cancer and Impact on Overall Survival.

OBJECTIVE: The aim of this study was to understand factors associated with refusal of local therapy in esophageal cancer and compare the overall survival (OS) of patients who refuse therapies with those who undergo recommended treatment. METHODS: National Cancer Database data for patients with non-metastatic esophageal cancer from 2006 to 2013 were pooled. T1N0M0 tumors were excluded. Pearson's Chi-square test and multivariate logistic regression analyses were used to assess demographic, clinical, and treatment factors. After propensity-score matching with inverse probability of treatment weighting, OS was compared between patients who refused therapies and those who underwent recommended therapy, using Kaplan-Meier analyses and doubly robust estimation with multivariate Cox proportional hazards modeling. RESULTS: In total, 37,618 patients were recommended radiation therapy (RT) and/or esophagectomy; we found 1403 (3.7%) refused local therapies. Specifically, 890 of 18,942 (4.6%) patients refused surgery and 667 of 31,937 (2.1%) refused RT. Older patients, females, those with unknown lymphovascular space invasion, and those uninsured or on Medicare were more likely to refuse. Those with squamous cell carcinoma, N1 disease, higher incomes, living farther from care, and those who received chemotherapy were less likely to refuse. Five-year OS was decreased in patients who refused (18.1% vs. 27.6%). The survival decrement was present in adenocarcinoma but not squamous cell carcinoma. In patients who received surgery or ≥ 50.4 Gy RT, there was no OS decrement to refusing the other therapy. CONCLUSIONS: We identified characteristics that correlate with refusal of local therapy. Refusal of therapy was associated with decreased OS. Patients who received either surgery or ≥ 50.4 Gy RT had no survival decrement from refusing the opposite modality.

How to keep registered nurses working in New Zealand even as economic conditions improve.

BACKGROUND: Many registered nurses (RNs) increased their participation in the New Zealand health workforce during the Global Financial Crisis (GFC), resulting in low vacancy rates. However, based on the documented impact of improving economies, a mean RN age of about 50, and just-agreed substantive increases in RN pay rates, it is likely that many will soon leave or reduce the hours they work. This study aims to investigate whether improved financial security will encourage RNs to leave or reduce their work commitment and to identify the factors that influence such intentions. METHODS: An exploratory study using a cross-sectional survey design. Data were collected in 2014-2015 via an e-survey of 2,910 RNs in New Zealand. Data were analysed by regression. RESULTS: We found that due to "burnout" and low "work engagement", both of which are strongly affected by workload and work-life interference, 22.6% of the RNs surveyed plan to leave work altogether and a further 32% plan to reduce their workforce participation when their financial situations improve. CONCLUSIONS: The findings justify the urgent cooperative development, implementation and evaluation of a comprehensive suite of RN 'retention' measures involving national nursing organisations, the RN regulator and health system employers and funders.

Developing and utilising a new funding model for home-care services in New Zealand.

Worldwide increases in the numbers of older people alongside an accompanying international policy incentive to support ageing-in-place have focussed the importance of home-care services as an alternative to institutionalisation. Despite this, funding models that facilitate a responsive, flexible approach are lacking. Casemix provides one solution, but the transition from the well-established hospital system to community has been problematic. This research seeks to develop a Casemix funding solution for home-care services through meaningful client profile groups and supporting pathways. Unique assessments from 3,135 older people were collected from two health board regions in 2012. Of these, 1,009 arose from older people with non-complex needs using the interRAI-Contact Assessment (CA) and 2,126 from the interRAI-Home-Care (HC) from older people with complex needs. Home-care service hours were collected for 3 months following each assessment and the mean weekly hours were calculated. Data were analysed using a decision tree analysis, whereby mean hours of weekly home-care was the dependent variable with responses from the assessment tools, the independent variables. A total of three main groups were developed from the interRAI-CA, each one further classified into "stable" or "flexible." The classification explained 16% of formal home-care service hour variability. Analysis of the interRAI-HC generated 33 clusters, organised through eight disability "sub" groups and five "lead" groups. The groupings explained 24% of formal home-care services hour variance. Adopting a Casemix system within home-care services can facilitate a more appropriate response to the changing needs of older people.

Using benchmarking to assist the improvement of service quality in home support services for older people-IN TOUCH (Integrated Networks Towards Optimising Understanding of Community Health).

Service providers and funders need ways to work together to improve services. Identifying critical performance variables provides a mechanism by which funders can understand what they are purchasing without getting caught up in restrictive service specifications that restrict the ability of service providers to meet the needs of the clients. An implementation pathway and benchmarking programme called IN TOUCH provided contracted providers of home support and funders with a consistent methodology to follow when developing and implementing new restorative approaches for service delivery. Data from performance measurement was used to triangulate the personal and social worlds of the stakeholders enabling them to develop a shared understanding of what is working and what is not. The initial implementation of IN TOUCH involved five District Health Boards. The recursive dialogue encouraged by the IN TOUCH programme supports better and more sustainable service development because performance management is anchored to agreed data that has meaning to all stakeholders.

Supported Discharge Teams for older people in hospital acute care: a randomised controlled trial.

Background: Supported Discharge Teams aim to help with the transition from hospital to home, whilst reducing hospital length-of-stay. Despite their obvious attraction, the evidence remains mixed, ranging from strong support for disease-specific interventions to less favourable results for generic services. Objective: To determine whether older people referred to a Supported Discharge Team have: (i) reduced length-of-stay in hospital; (ii) reduced risk of hospital readmission; and (iii) reduced healthcare costs. Methods: Randomised controlled trial with follow-up to 6 months; 103 older women and 80 men (n = 183) (mean age 79), in hospital, were randomised to receive either Supported Discharge Team or usual care. Home-based rehabilitation was delivered by trained Health Care Assistants up to four times a day, 7 days a week, under the guidance of registered nurses, allied health and geriatricians for up to 6 weeks. Results: Participants randomised to the Supported Discharge Team spent less time in hospital during the index admission (mean 15.7 days) in comparison to usual care (mean 21.6 days) (mean difference 5.9: 95% CI 0.6, 11.3 days: P = 0.03) and spent less time in hospital in the 6 months following discharge home. Supported discharge group costs were calculated at mean NZ$10,836 (SD NZ$12,087) compared to NZ$16,943 (SD NZ$22,303) in usual care. Conclusion: A Supported Discharge Team can provide an effective means of discharging older people home early from hospital and can make a cost-effective contribution to managing increasing demand for hospital beds.

Palliative Care Need and Availability in Four Referral Hospitals in Senegal: Results from a Multicomponent Assessment.

CONTEXT: With prevalence of noncommunicable diseases and life expectancy rising in Senegal, the need for palliative care is likely growing. No national palliative care needs assessments have been carried out. OBJECTIVES: To assess the capacity and need for palliative care in Senegal. METHODS: A multicomponent assessment of availability and demand for palliative care was conducted in two tertiary and two regional hospitals in Senegal in 2015 with approval from Senegal's National Ethics Committee for Health Research. The assessment consisted of (1) an inpatient hospital census; (2, 3) surveys of inpatients and outpatients with life-limiting illness; (4) a knowledge, attitudes, and practices survey among health care workers; and (5) a facility survey to assess availability of palliative care medications. RESULTS: Nearly half (44.4%) of all inpatients (n = 167) had an active life-limiting illness. Among them, 56.6% reported moderate-to-severe pain in the past three days, 2.3% of whom received morphine, and 76.7% received weak or no pain medication. Inpatients also experienced moderate-to-severe dyspnea (42.1%), fatigue (66.5%), nausea (16.5%), and drowsiness (42.1%). About 39.2% of all outpatients (n = 395) reported moderate-to-severe pain, and 52.8% reported that the treatment they had received relieved their pain only partially or not at all. Two-thirds of all doctors reported feeling comfortable prescribing pain medicines; however, 83.0% rarely or never prescribed morphine. Two of four hospitals reported no use of morphine in 2014. CONCLUSION: There is significant need for palliative care in Senegal. Training of health care workers and ensuring availability of relevant medications should be prioritized.

Telecare for diabetes, CHF or COPD: effect on quality of life, hospital use and costs. A randomised controlled trial and qualitative evaluation.

OBJECTIVES: To assess the effect of telecare on health related quality of life, self-care, hospital use, costs and the experiences of patients, informal carers and health care professionals. METHODS: Patients were randomly assigned either to usual care or to additionally entering their data into a commercially-available electronic device that uploaded data once a day to a nurse-led monitoring station. Patients had congestive heart failure (Site A), chronic obstructive pulmonary disease (Site B), or any long-term condition, mostly diabetes (Site C). Site C contributed only intervention patients - they considered a usual care option to be unethical. The study took place in New Zealand between September 2010 and February 2012, and lasted 3 to 6 months for each patient. The primary outcome was health-related quality of life (SF36). Data on experiences were collected by individual and group interviews and by questionnaire. RESULTS: There were 171 patients (98 intervention, 73 control). Quality of life, self-efficacy and disease-specific measures did not change significantly, while anxiety and depression both decreased significantly with the intervention. Hospital admissions, days in hospital, emergency department visits, outpatient visits and costs did not differ significantly between the groups. Patients at all sites were universally positive. Many felt safer and more cared-for, and said that they and their family had learned more about managing their condition. Staff could all see potential benefits of telecare, and, after some initial technical problems, many staff felt that telecare enabled them to effectively monitor more patients. CONCLUSIONS: Strongly positive patient and staff experiences and attitudes complement and contrast with small or non-significant quantitative changes. Telecare led to patients and families taking a more active role in self-management. It is likely that subgroups of patients benefitted in ways that were not measured or visible within the quantitative data, especially feelings of safety and being cared-for. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12610000269033.

Location of core diagnostic information across various sequences in brain MRI and implications for efficiency of MRI scanner utilization.

OBJECTIVE: Targeting redundancy within MRI can improve its cost-effective utilization. We sought to quantify potential redundancy in our brain MRI protocols. MATERIALS AND METHODS: In this retrospective review, we aggregated 207 consecutive adults who underwent brain MRI and reviewed their medical records to document clinical indication, core diagnostic information provided by MRI, and its clinical impact. Contributory imaging abnormalities constituted positive core diagnostic information whereas absence of imaging abnormalities constituted negative core diagnostic information. The senior author selected core sequences deemed sufficient for extraction of core diagnostic information. For validating core sequences selection, four readers assessed the relative ease of extracting core diagnostic information from the core sequences. Potential redundancy was calculated by comparing the average number of core sequences to the average number of sequences obtained. RESULTS: Scanning had been performed using 9.4±2.8 sequences over 37.3±12.3 minutes. Core diagnostic information was deemed extractable from 2.1±1.1 core sequences, with an assumed scanning time of 8.6±4.8 minutes, reflecting a potential redundancy of 74.5%±19.1%. Potential redundancy was least in scans obtained for treatment planning (14.9%±25.7%) and highest in scans obtained for follow-up of benign diseases (81.4%±12.6%). In 97.4% of cases, all four readers considered core diagnostic information to be either easily extractable from core sequences or the ease to be equivalent to that from the entire study. With only one MRI lacking clinical impact (0.48%), overutilization did not seem to contribute to potential redundancy. CONCLUSION: High potential redundancy that can be targeted for more efficient scanner utilization exists in brain MRI protocols.

Promoting independence in frail older people: a randomised controlled trial of a restorative care service in New Zealand.

BACKGROUND: frail older people often require tailored rehabilitation in order to remain at home, especially following a period of hospitalisation. Restorative care services aim to enhance an older person's ability to remain improve physical functioning, either at home or in residential care but evidence of their effectiveness is limited. OBJECTIVE: to evaluate the effectiveness of a restorative care service on institutional-free survival and health outcomes in frail older people referred for needs assessment in New Zealand. METHODS: a randomised controlled trial of restorative care or usual care in 105 older people at risk of permanent residential who were follow-up over 24 months. The restorative care service was delivered in short-stay residential care facilities and at participants' residences with the aim of reducing the requirement for permanent residential care. It included a comprehensive geriatric assessment and care plan developed and delivered, initially by a multi-disciplinary team and subsequently by home care assistants. RESULTS: compared with usual care, there was a non-significant absolute risk reduction of 14.3% for death or permanent residential care (8.8% for residential care and 7.2% for death alone) for the restorative care approach. There was no difference in levels of burden among caregivers. CONCLUSIONS: restorative care models that utilise case management and multi-disciplinary care may positively impact on institutional-free survival for frail older people without adversely impacting on the health of caregivers.

A two-tiered approach to MRI for hearing loss: incremental cost of a comprehensive MRI over high-resolution T2-weighted imaging.

OBJECTIVE: The objective of our study was to compare the cost-effectiveness of two approaches to using MRI for the evaluation of patients with hearing loss. MATERIALS AND METHODS: We developed a decision tree to compare the cost-effectiveness of conventional MRI with that of a proposed two-tiered model in which an initial 3D T2-weighted imaging examination was used to determine the need for comprehensive MR scanning. Three radiologists independently and blindly reviewed the 3D T2-weighted images acquired as part of the comprehensive MR examinations of 256 patients with hearing loss to assess the diagnostic efficacy of the two-tiered approach. Costs were defined in terms of both the scanner utilization time for the imaging facility and the dollar amount for payers. Effectiveness was defined in terms of the ability to correctly detect the presence or absence of disease. RESULTS: The conventional approach was less cost-effective, with a baseline incremental cost-effectiveness ratio (ICER) of 27,299 minutes of scanner utilization per unit increase in effectiveness. Assuming a 50% reduction in the reimbursement of the technical component from the current level by the Centers for Medicare & Medicaid Services, this result reflected an ICER of $258,664 per unit increase in effectiveness. The results of a sensitivity analysis showed the robustness of the cost-effectiveness of the two-tiered imaging approach in a variety of scenarios that reflect differences in scanning practices and possible differences in recall rates. The conventional imaging approach was absolutely dominated by the two-tiered approach in the scenarios created to reflect the expected range of prevalence of disease. CONCLUSION: A two-tiered approach to MRI provides a more cost-effective alternative to the current approach of using a comprehensive MRI examination without and with contrast material to evaluate patients with hearing loss.

Two-tiered approach to MRI for headache: a cost-effective way to use an expensive technology.

OBJECTIVE: The purpose of this study was to compare the diagnostic efficacy and cost implications of a proposed two-tiered approach to MRI in patients with headache. MATERIALS AND METHODS: We identified 245 consecutive patients with headache using MRI studies performed at a tertiary care facility between October 2009 and July 2011. Three radiologists prospectively used FLAIR sequences from these MR studies to diagnose underlying abnormality or to identify the need for a comprehensive MRI study. We compared the diagnostic efficacy and the cost implications of such a two-tiered approach with those of conventional MRI from the perspectives of the payer, the patient, and the imaging facility. RESULTS: The sensitivity and specificity for two-tiered (83.3% and 100%, respectively) and conventional (91% and 97.8%, respectively) MRI approaches were not significantly different. Assuming a 50% reduction in the payment for the initial limited MRI performed as a first step of the two-tiered approach, this approach would have resulted in 44.8% savings to the payer. A substantial reduction in the scanner utilization time from 4168 minutes to 1249 minutes for the two-tiered approach would have enabled increased throughput at the imaging facility. Although 27 (11%) patients would have been recalled for a comprehensive MRI study in the two-tiered approach, the average time spent in the scanner by each patient would have been less for the two-tiered approach (5.1 minutes vs 17.0 minutes). CONCLUSION: A two-tiered approach to MRI can serve as a viable cost-effective alternative to the conventional approach.

Assessment without action; a randomised evaluation of the interRAI home care compared to a national assessment tool on identification of needs and service provision for older people in New Zealand.

Comprehensive geriatric assessment (CGA) is considered the cornerstone of good practice, as it identifies need across multiple domains such as social, physical and psychological. The interRAI home care (interRAI-HC), probably the most well-researched and supported community-based CGA has been implemented globally, often at considerable expense. Policy-makers, managers and clinicians anticipate significant gains in health outcomes following such investment; however, the implementation of CGA is often undertaken in the absence of community service development. This study sought to compare the interRAI-HC with an existing CGA [the Support Needs Assessment (SNA)] in community-dwelling older people. A randomised controlled trial was undertaken from January 2006 to January 2007 comparing the interRAI-HC and the SNA in 316 people (65+) referred for assessment of needs with follow-up at 1 and 4 months. Outcomes included health-related quality of life, physical function, social support, cognitive status, mood and health service usage as well as identified need. The study found that significantly more support needs were identified using the interRAI-HC compared to the SNA. More social and carer support were recommended by SNA and more rehabilitation and preventive health screens were recommended by interRAI-HC. Despite these differences, the mean healthcare use was similar at 4 months, although interRAI-HC participants had more Emergency Department presentations and hospital admissions. No statistically significant differences between groups were reported in terms of outcomes. In conclusion, the interRAI-HC was found to identify more unmet support needs than the SNA though resulted in no favourable outcomes for the older person or their carer. The study highlights the need to invest attention around the service context to maximise outcomes based on identified needs.

The Assessment of Services Promoting Independence and Recovery in Elders Trial (ASPIRE): a pre-planned meta-analysis of three independent randomised controlled trial evaluations of ageing in place initiatives in New Zealand.

INTRODUCTION: intermediate care has been developed to support older people to remain living in their own homes, combining a higher level of support with a rehabilitation focus. Evidence around their effectiveness remains mixed and there is ambiguity around the components. AIMS: to establish the impact of intermediate care on institutional free survival in frail older people referred for needs assessment in New Zealand (NZ). METHODS: pre-planned meta-analysis of three randomised controlled trials with follow-up at 3, 6, 12, 18 and 24 months. A total of 567 older people at risk of permanent institutionalisation as well as their primary informal carer (n = 234) were randomised to either intermediate or usual care. Interventions had common key features of care management, though varied in the use of ongoing care provision. RESULTS: the adjusted hazard ratio for the combined primary outcome of death or residential entry was 31% lower with a 95% confidence interval of (9%, 47%) for the intermediate care initiatives compared with usual care. CONCLUSION: intermediate care utilising a care management approach reduces a frail older person's risk of mortality and permanent institutionalisation.

Integrated systems to improve care for very high intensity users of hospital emergency department and for long-term conditions in the community.

Adult patients who are very high intensity users of hospital emergency departments (VHIU) have complex medical and psychosocial needs. Their care is often poorly coordinated and expensive. Substantial health and social resources may be available to these patients but it is ineffective for a variety of reasons. In 2009 Counties Manukau District Health Board approved a business case for a programme designed to improve the care of VHIU patients identified at Middlemore Hospital. The model of care includes medical and social review, a multidisciplinary planning approach with a designated 'navigator' and assertive follow-up, self and family management, and involvement of community based organisations, primary care and secondary care. The model has been organised around geographic localities and alongside other initiatives. An intermediate care team has been established to attend to the current presenting problems, however the main emphasis is on optimising ongoing care and reducing subsequent admissions especially by connecting patients with primary health care. This whole process could be driven by the primacy care sector in due course. The background and initial experience with implementation are described.