Motorcycle Drivers Research Articles

High-risk motorcycle taxi drivers in the HIV/AIDS era: a respondent-driven sampling survey in Kampala, Uganda.

We evaluated motorcycle taxi ('boda-boda') drivers in Kampala for the prevalence of HIV/sexually transmitted infections. We used respondent-driven sampling to recruit a cross-sectional sample of boda-boda drivers. We collected data through audio computer-assisted self-administered interviews. Men were tested for HIV, syphilis serology using Rapid Plasma Reagin and enzyme immunoassay, and Chlamydia and gonorrhoea using urine polymerase chain reaction. We recruited 683 men. Median age was 26 years; 59.4% were single. The prevalence of HIV was 7.5% (95% CI 5.2-10.0), of positive syphilis serology was 6.1% (95% CI 4.3-8.1), of Chlamydia was 1.1% (95% CI 0.4-2.0), and of gonorrhoea was 1.2% (95% CI 0.1-1.2). Many men (67.8%) had both casual and regular partners, sex with other men (8.7%), and commercial sex (33.1%). Factors associated with having HIV included reporting a genital ulcer (odds ratio [OR] =2.4, 95% CI 1.4-4.4), drinking alcohol during last sex (OR 2.0, 95% CI 1.1-3.7), having 4-6 lifetime partners (OR 2.2, 95% CI 1.0-4.8), and having one's last female partner be >24 years of age (OR 2.8, 95% CI 1.2-6.6). Independent predictors of HIV included age ≥31 (adjusted OR (aOR) 5.8, 95% CI 1.5-48.5), having 4-6 partners (aOR 2.2, 95%CI 1.0-5.1), and self-report of a genital ulcer (OR 2.3, 95% CI 1.2-4.1). Only 39.2% of men were circumcised, and 36.9% had been HIV tested in the past. Male boda-boda drivers have a higher prevalence of HIV than the general population, and low frequency of preventive behaviours, such as circumcision and HIV testing. Targeted and intensified interventions for this group are warranted.

Poluição do ar relacionada ao tráfego urbano e carbono preto em macrófagos de escarro: uma doença pulmonar "silenciosa"?

AIMS: To describe two case reports with significant black carbon deposition in sputum macrophages in healthy young adults from an urban city, showing mild airway obstruction in lung function tests. The role of black carbon deposition by air pollution in the airways and the development of indolent chronic lung disease in populations living in larger cities is not clear and may be a potential world health problem. CASES DESCRIPTION: We report two cases of voluntary adults living in a South American large city who have undergone clinical examination, lung function and analysis of inflammation and black carbon deposition in macrophages from induced sputum. Two Caucasian, previously healthy, nonsmokers, male adults, living in the same city of southern Brazil, with no respiratory symptoms presented with normal physical exams, but with lung function demonstrating mild obstructive lung disorder, with no bronchodilator response. In particular, one of the subjects works daily in delivery services as a motorcycle driver. Induced sputum of both patients showed no signs of cellular inflammation. However, a large number of black carbon content was detected inside macrophages of the sputum sample in both patients. CONCLUSIONS: In summary, significant daily air pollution exposure may play a role in long-term silent disease in adults, potentially leading to clinically relevant chronic lung diseases later in life, particularly in populations of urbanized large cities from developing countries. The development of better, more directly and less invasive, methods for air pollution exposure are required, along with longitudinal studies, in order to measure the real impact of air pollution in chronic lung diseases of susceptible populations.

Commercial motorcycle drivers' perceptions of risk and road safety in urban Nigeria: an explorative study

Road traffic injury is a great public health challenge with an emerging trend of increasing rates and high mortality involving commercial motorcycles in Nigeria. A qualitative approach was used with 10 in-depth interviews conducted to explore the risk perceptions of commercial motorcyclists in Ibadan, Nigeria. The data analysis using manifest and latent content analysis resulted in an overarching theme: inadequate structures and internalised norms prevent change. The three themes leading to the overarching theme are: risk-taking as generally acceptable; risk-taking as an intrinsic part of occupation; and risk-taking as a way to make ends meet. The study suggests that there is a great need for adequate regulation as regards training and licensing of riders. Also the need to tighten enforcement of traffic rules is paramount to road safety in Nigeria.

Effect of free distribution of safety equipment on usage among motorcycle–taxi drivers in Tanzania—A cluster randomised controlled trial

IntroductionDeaths due to road traffic injuries, particularly motorcycle crashes, have increased rapidly in many African nations and context-specific strategies to improve preventative behaviours are needed. Although adhering to conspicuity measures by wearing reflective safety vests is a highly effective crash prevention strategy and mandated by law among motorcycle–taxi drivers in some African countries, actual use is currently low. We aimed to test whether eliminating cost-barriers through the provision of free reflective, fluorescent motorcycle safety vests would lead to increased utilisation among a high-risk population of motorcycle–taxi drivers in Tanzania. MethodsA cluster randomised controlled trial was conducted among 180 motorcycle–taxi drivers. Participants randomised to the intervention arm (90) received free, reflective, fluorescent vests; participants randomised to the control arm (90) did not receive free vests. Participants’ use of reflective vests was then observed on city streets over a three month period and differential uptake was estimated using mixed-effects logistic regression. ResultsBaseline use of reflective vests was 3.3% in both arms. Seventy-nine drivers in the intervention arm and 82 drivers in the control arm were observed during follow-up. The average proportion of observations during which motorcycle drivers were using a reflective vest was 9.5% in the intervention arm, compared to 2.0% in the control arm (odds ratio: 5.5, 95% confidence interval: 1.1–26.9, p-value: 0.04). ConclusionAlthough distribution of free reflective vests led to a statistically significant increase in vest usage, the absolute increase was modest. Additional strategies beyond removing economic barriers are important to augment adherence to road safety behaviours for injury prevention.

Owners of the Map: Mobility and Mobilization among Motorcycle Taxi Drivers in Bangkok

AbstractIn this article, I discuss the connection between spatial mobility and political mobilization among motorcycle taxi drivers during the 2010 protests in Bangkok. Through the study of their multiple roles, both as transport operators and as political mobilizers, I explore the nexus of mobility and mobilization and analyze motorcycle taxi drivers as central political actors in contemporary Thailand. In this sense, the article focuses on investigating the historical emergence of “technique of mobilization” based on modulation and control over mobility. I analyze acts of disruption of movement along major infrastructures as moments of time‐space modulation as well as transformative strategies that set in motion alternative messages and configure new modalities of political mobilization. Focusing on such techniques, both in the 2010 Red Shirts protest and in other Thai political mobilizations, I explore the solidification of spaces of mobility as major political arenas for political struggles in contemporary Thailand.

Health Risk Assessment and Urinary Biomarkers of VOCs Exposures among Outdoor Workers in Urban Area, Bangkok, Thailand

Volatile organic compounds (VOCs) are major source of ambient air pollutants in Bangkok, Thailand. Humans can be exposed to these pollutants by inhalation, ingestion, and dermal contact but mainly by inhalation. The scientists have paid much attention to the study of exposure to air pollutants in outdoor air because they have realized the seriousness of outdoor air pollution problems of acute and chronic health effects as cancer. The measurements of benzene, toluene, ethylbenzene, xylene (BTEX) and carbonyl compounds (CCs) at 16 sites with 144 subjects of 3 classes (motorcycle drivers, security guardsmen and street venders) were performed in Pathumwan district, central Bangkok during September and October 2012 by Gas Chromatography/Flame Ionized Detector (GC/FID) and High Performance Liquid Chromatography/Ultraviolet-Visible Detector (HPLC/UV-VIS). The ambient air concentrations of benzene, toluene, ethyl benzene, xylene, formaldehyde and acetaldehyde in urban area were 46.13, 91.10, 4.55, 58.27, 11.98 and 5.85 µg/m3 respectively. The outdoor workers had average lifetime cancer risk of benzene, ethylbenzene, formaldehyde and acetaldehyde at 1.67E05, 2.11E-07, 3.38E-06 and 7.93E-07 respectively which cancer risk of benzene and formaldehyde were higher than acceptable limit (1.00E-06). The security guardsmen, motorcycle drivers and street venders who work in the same area had cancer risk at 3.65E-05, 1.76E-05 and 1.01E-05 respectively The hazard quotient (HQ) of benzene, toluene, ethylbenzene, xylene, formaldehyde and acetaldehyde of all workers were 9.43E02, 9.57E-04, 4.43E-04, 4.04E-02, 1.42E-01 and 7.64E-01 respectively which all of them were lower than acceptable limit (HQ<1.00). In addition, the urinary biomonitoring concentrations of outdoor workers of trans,trans-muconic acid (tt-MA), hippuric acid, formaldehyde, acetaldehyde and formic acid were 1.66 mg/gCr, 0.51 g/gCr, 0.85 mg/gCr, 15.9 mg/gCr and 20.57 mg/gCr respectively. The tt-MA was strongly associated with benzene exposure (p<0.001) as well as hippuric acid was associated with toluene (p=0.001).

A Retrospective Study on the Unseen Epidemic of Road Traffic Injuries and Deaths Due to Accidents in Mwanza City—Tanzania

Backgrounds: Sixty percent of the global deaths and injuries occur in the developing world and mostly are due to Road traffic accidents (RTAs). Looking at the etiological related factors which include carelessness of the driver, condition of the vehicle or motorcycle, poor condition of roads, risky behavior of the driver, most of these factors can be prevented to some extent. This study therefore, determined the pattern of cases and deaths due to traffic road accidents in Mwanza City Tanzania. Methods: In this retrospective study, records, registers and case notes in the surgical ward and causality, medical records and central police station from 2009 to 2012 were used. The study focused on the two referral hospitals (Sekouture regional hospital and Bugando Medical Center). Results: There were 3450 cases due to accidents reported at both centers (Sekouture regional hospital and Bugando Medical Center of which 3224 (93.4%) had complete information for analysis. 2225 (69%) were male and 999 (31%) were female, and the most affected group were male. Among the RTAs 2809 cases (87%) were due to motor cycle accidents which were the leading cause of RTAs with case fatality rate of 5% while motor vehicle has case fatality rate of 24% which is 5 times that of motor cycle. Conclusion: Among all RTAs the leading cause of injuries is Motor cycle traffic accidents followed by motor vehicle. RTAs are on increase particularly the motor cycle traffic accidents and have claimed a good number of innocent people’s lives however most of them are preventable, therefore driving course to be introduced to motor cycle drivers emphasizes on the road posters signal, rules and regular checkup of their motor cycles especially commercial motor cycle.

Traumatic Hemipelvectomy: Surgical and Medical-Legal Aspects

Background: Traffic accidents are major causes of disability and mortality due to the increasing number of vehicles, changes in lifestyle and high-risk behavior among the general population. Traumatic hemipelvectomy is a type of exceptional lesion representing 0.6% of all pelvic fractures, although lesions of the lower extremities are more usual than those of the upper extremities.Case presentation: The authors present an unusual case of traumatic left hemipelvectomy, and consider the medical-legal aspects resulting from an accident of a motorcycle driver, which involved a lateral collision between the subject’s motorcycle and a car.Conclusion: With traumatic hemipelvectomy in young subjects difficulties arise at any level and in all medical fields: clinically, surgical and medicolegal

Analysis of Effects of Manhole Covers on Motorcycle Driver Maneuvers: A Nonparametric Classification Tree Approach

Objective: A manhole cover is a removable plate forming the lid over the opening of a manhole to allow traffic to pass over the manhole and to prevent people from falling in. Because most manhole covers are placed in roadway traffic lanes, if these manhole covers are not appropriately installed or maintained, they can represent unexpected hazards on the road, especially for motorcycle drivers. The objective of this study is to identify the effects of manhole cover characteristics as well as driver factors and traffic and roadway conditions on motorcycle driver maneuvers. Method: A video camera was used to record motorcycle drivers’ maneuvers when they encountered an inappropriately installed or maintained manhole cover. Information on 3059 drivers’ maneuver decisions was recorded. Classification and regression tree (CART) models were applied to explore factors that can significantly affect motorcycle driver maneuvers when passing a manhole cover. Results: Nearly 50 percent of the motorcycle drivers decelerated or changed their driving path to reduce the effects of the manhole cover. The manhole cover characteristics including the level difference between manhole cover and pavement, the pavement condition over the manhole cover, and the size of the manhole cover can significantly affect motorcycle driver maneuvers. Other factors, including traffic conditions, lane width, motorcycle speed, and loading conditions, also have significant effects on motorcycle driver maneuvers. Conclusions: To reduce the effects and potential risks from the manhole covers, highway authorities not only need to make sure that any newly installed manhole covers are as level as possible but also need to regularly maintain all the manhole covers to ensure that they are in good condition. In the long run, the size of manhole covers should be kept as small as possible so that the impact of manhole covers on motorcycle drivers can be effectively reduced. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.

Performance, poverty and urban development: Kigali’s motari and the spectacle city

In this paper I explore tensions and conflicts over poverty reduction and urban development in Kigali, Rwanda’s capital in terms of theories of performativity. On one hand, motorcycle taxis offer large numbers of young men good livelihoods – reflecting the government of Rwanda’s stated commitment to poverty reduction, especially amongst youth; on the other, motorcycle taxi drivers suffer harassment at the hands of city authorities and police, who are keen to eradicate motorcycle taxis from the urban scene altogether. I interpret this tension as a conflict over the appropriate performance of development in the city; I argue that in pursuit of urban development, the city itself becomes an image, projected in order to attract the investment which will give body to the simulated spectacle that Kigali present. Conflicts between the city and motorcycle taxi drivers erupt because motorcycle taxis cannot perform to the aesthetic standards of the new Kigali. In conclusion, I suggest that the rendition of Kigali’s development as image has broader lessons for studies of development in general. Specifically, these conflicts expose the operation of images and their performance as political resources, conferring intelligibility and legitimacy in the spectacle of national development. Key words: Rwanda, poverty reduction, urban development, performativity

Does law enforcement awareness affect motorcycle helmet use? Evidence from urban cities in Thailand

Although helmet use has been compulsory for motorcycle drivers and passengers in Thailand since the enactment of the Helmet Act in 1994, recent surveys show that the prevalence of helmet usage remains low, particularly among passengers. This paper has sought to explore motorcyclists' awareness of helmet law enforcement in Thailand and examine whether it affects their helmet use behaviour. A total of 2,429 drivers and 1,328 passengers in urban cities nationwide were interviewed in 2009, and the data were analysed using a multivariate ordered logit regression technique. About 60% of the drivers and only 28% of the passengers reported that they always wore a motorcycle helmet. Apart from basic demographics (i.e. age and gender) and riding frequency, our analysis reveals that the awareness of helmet law enforcement was among the contributing factors influencing the use of motorcycle helmets in Thailand. Regardless of riding position, the prevalence of helmet use tended to be greater among those frequently observing the police's checkpoints for helmet wearing and those perceiving the high risk of being caught for non-helmet use. However, the use of helmets appeared to be lower among drivers who perceived the checkpoints to take place at the same times and locations, which were likely predicted. For motorcycle passengers, it was found that the low prevalence of helmet use was potentially attributable to the absence of knowledge on the compulsory helmet law for passengers and the perception that the law was not enforced by the police. Thus, if motorcycle helmet use in Thailand is to be increased, considerable efforts need to be given to increasing the perceived risk of apprehension for non-helmet use (e.g. more police presence and random scheduling of enforcement activities), improving the awareness of the existing helmet law for passengers, and ensuring that helmet wearing by passengers is more strictly enforced.

Epidemiological characteristics of fatal traffic accidents in Fars province, Iran: a community-based survey

ObjectivesTo determine the epidemiological characteristics of fatal traffic accidents in Fars province, Iran. Study designThis cross-sectional study included 3642 traffic accident deaths in Fars province, Iran between November 2009 and November 2011. The data source was the Fars Forensic Medicine Registry, which covers the entire province. According to Iranian law, all deaths resulting from injuries or accidents must be investigated to determine the exact cause of death by autopsy. All such deaths are referred to forensic medicine centres in each city, and all data are sent to the main centre in Shiraz, the capital city of Fars province. ResultsMales accounted for 78.3% of the decedents (sex ratio of almost 3.6:1), and the mean ± standard deviation age of all decedents was 32.2 ± 20.3 years. Autopsy reports indicated that head trauma was the most common cause of death. Most collisions were vehicle–vehicle crashes (52.3%), with cars and motorcycles being the most prevalent modes of transport (39.6% and 24.6%, respectively). Fatal accidents were most common during the summer. Most fatal injuries (61.4%) occurred on outer-city roads and 27.4% occurred on inner-city roads. Significant associations were found between decedent's status (car driver, motorcycle driver or passenger, pedestrian or passenger) and interval between injury and death, light conditions at the scene of the accident, place of death, site of injury and cause of death. ConclusionAlthough the clinical management of trauma patients has improved in Iran, coordination between trauma system organizations is required to decrease the burden of injuries.

Motorcycle Handlebar Dynamic Response: Theoretical and Experimental Investigation

Motorcycle driver interacts with the vehicle through the hands, feet and buttocks. Through these parts of the body, the driver perceives vibrations due to engine and road roughness. A good level of comfort would require that handlebar and foot pegs natural frequencies should not line up with the operating range frequencies. In this paper the results of experimental tests direct to investigate the handlebar dynamic response is reported; the investigation is adopted to evaluate the possibility of adopting a vibration exciter placed in correspondence of the grips that could provide an alarm signal when a danger situation occur. This type of active assistance has already been used for cars and has proved effective in the accidents prevention.

Performance, poverty and urban development: Kigali’s motari and the spectacle city

In this paper I explore tensions and conflicts over poverty reduction and urban development in Kigali, Rwanda’s capital in terms of theories of performativity. On one hand, motorcycle taxis offer large numbers of young men good livelihoods – reflecting the government of Rwanda’s stated commitment to poverty reduction, especially amongst youth; on the other, motorcycle taxi drivers suffer harassment at the hands of city authorities and police, who are keen to eradicate motorcycle taxis from the urban scene altogether. I interpret this tension as a conflict over the appropriate performance of development in the city; I argue that in pursuit of urban development, the city itself becomes an image, projected in order to attract the investment which will give body to the simulated spectacle that Kigali present. Conflicts between the city and motorcycle taxi drivers erupt because motorcycle taxis cannot perform to the aesthetic standards of the new Kigali. In conclusion, I suggest that the rendition of Kigali’s development as image has broader lessons for studies of development in general. Specifically, these conflicts expose the operation of images and their performance as political resources, conferring intelligibility and legitimacy in the spectacle of national development.

The Result of a Baseline Survey on Drink Driving in Nanning and Liuzhou of Guangxi Province, China

Objective: Because the official data in China on drink-driving accidents as well as related fatalities and injuries are much lower than many of the developed and developing countries in the world, the Global Road Safety Partnership (GRSP) decided to conduct a baseline survey to understand the prevalence of drink driving and related accidents in Nanning and Liuzhou, both in Guangxi Province, in order to develop targeted interventions. Methods: The baseline survey included a roadside survey and an accident survey. Motor vehicle (including motorcycles) drivers were randomly stopped for a breath test and interview in the roadside survey. In the accident survey, all drivers involved in a road accident resulting in at least 1 person killed or seriously injured were requested to provide a blood sample. Results: A total of 10,685 drivers accepted the random breath test and 10,666 drivers were interviewed in the roadside survey. An examination of the raw (unweighted) breath alcohol readings reveals that of the 10,685 breath-tested drivers, 730 (6.8%) had positive blood alcohol concentrations (BACs); 245 of these drivers (2.3% of all drivers) had BACs below 20 mg/100 mL; 415 (3.9% of all drivers) were driving under the influence (DUI; 20 mg/100 mL–80 mg/100 mL); and 70 (0.7% of all drivers) were driving while intoxicated (DWI; ≥0.80 mg/100 mL). Overall, 4.6 percent of the drivers had BACs over 20 mg/100 mL (the lowest legal BAC limit in China). Among the 10,666 interviewed drivers, only 4.8 percent were aware of the lowest national BAC limit (20 mg/100 mL); 24.9 percent had been discouraged by other people from driving after drinking; 78 percent had never been stopped by the traffic police for a BAC check during the last 2 years (during 2005–2006), and only 0.3 percent had been punished for drink driving. The accident survey results revealed that an average of 34.1 percent of road accidents (Nanning: 25.7%; Liuzhou: 48%) were alcohol related; the mean BAC level of the drivers in the accidents was 156.7 mg/100 mL and the highest was 310 mg/100 mL. Conclusions: Valuable information was obtained from the baseline survey to provide a better understanding of the drink driving situation in Nanning and Liuzhou. From the survey data it can be seen that drinking and driving was a major issue in both cities. A drink driving intervention was developed with both components of public education/social marketing and enforcement activities after the survey, which was conducted in 2008. However, this article will focus on the methodology and results of the baseline survey, not the activities and outcome of the intervention.

Bronchospasm Diagnosis in Motorcycle Taxi Drivers Exposed to Automotive Pollutants in Porto-Novo

Background: In African cities, chronic exposure to pollutants is the most common public health problem faced daily by motorcycle taxi drivers. In Benin, studies conducted on motorcycle drivers, have shown the presence of nitrogen oxides, carbon monoxide, sulfur dioxide, volatile organic compounds and particulate matter in ambient air, which may affect lung function. Aims: This study aims to diagnose potential respiratory problems among 48 motorcycle taxi drivers (47.02 ± 8.75 years) compared to a control group made up of 52 people (46.38 ± 8.81 years) in Porto-Novo, Benin. Methods: A questionnaire, two exploration pulmonary function tests and two 6-minute walk tests were used to identify symptoms and changes in respiratory variables that reveal the existence of bronchospasm. Results: The frequency of respiratory symptoms noted among motorcycle taxi drivers is higher than that recorded among members of the control group. We observed that motorcycle drivers at rest and after physical effort have significantly lower respiratory variables (FVC, FEV1, PEF, FEF25-75, FEF50 and FEF25) (p halation of automobile pollutants, may cause respiratory problems in this population.

On Various Essential Data Related to Status Quo of Motorcycles in Vietnam

Motorcycles take a majority in the road vehicle fleet of Vietnam, but there is no data on the number in current traffic circulation. This study presents a methodology to calculate this quantity (Mcir). Until now, in all existing works, the numbers of registered motorcycles are used instead of Mcir in ignoring the fact that after several years many vehicles have been excluded out of circulation. The use of correct Mcir could lead to better and more economical transport solutions. The paper also investigates the violations related to motorcycle driver license and shows that the level of such violations is serious. Furthermore, the paper shows methods to calculate the average use life, number of current users, and rate of users per one motorcycle. Especially, the short use life shows one sign for bad technical quality of existing vehicles. Last but not least, the paper presents a prediction of motorcycle numbers until 2020.

Perfil das ocorrências de politrauma em condutores motociclísticos atendidos pelo SAMU de Teresina-PI

O estudo objetivou investigar o perfil das ocorrências de politrauma em condutores motociclísticos atendidos pelo Serviço de Atendimento Móvel de Urgência de Teresina-PI. Realizou-se um estudo quantitativo e documental, mediante informações colhidas das fichas de atendimento desse serviço no ano de 2009. A coleta dos dados ocorreu nos meses de fevereiro e março do ano de 2010. As motocicletas envolveram-se em 84% dos acidentes, sendo os homens de 21 a 30 anos os mais acometidos. O final de semana e a zona urbana registraram mais casos. Destacaram-se os traumas musculoesqueléticos (59%). As vítimas alcoolizadas totalizaram 12%. A mortalidade correspondeu a 1%. Conclui-se ser imprescindível a adoção de medidas socioeducativas que garantam o comportamento adequado dos indivíduos no trânsito.

Motorcycle Modeling with SimMechanics

A new motorcycle multi-body modeling technique with SimMechanics was presented which can be used in vehicle handling and stability analysis. The established model included tyre nonlinear characters and vehicle frame compliance. Combining with motorcycle driver model, established in Simulink, a typical vehicle handling test was implemented. With Simulink Virtual Reality, the animation of the motorcycle test was realized.

Online simulation for a real-time route dispatching problem

In this article we present an online simulation application for a decision problem that operates in real time, where products have to be dispatched from two depots to clients that are geographically distributed throughout the city. The system's behaviour is highly stochastic, due to the random behaviour of the client's demand (in time and space), and the random times of order preparation, travelling times of dispatchers (these are motorcycle drivers) and absence rate of drivers each day. A decision scheme is proposed that combines elements of vehicle routing with time windows, real-time dispatching of drivers and online simulation, through which information on future events is considered in the decision-making process. Two major conclusions are obtained when this scheme is applied to real data. First, we show that the proposed algorithm for order consolidation and route dispatching can be very advantageous from the point of view of logistics costs and quality of service. Second, we show that online simulation and, specifically, the Simulation-based Real-time Decision Making methodology (SRDM) can further improve the quality of the results. New ideas for further work are also proposed.