836 resultados para field study
Resumo:
Rail corrugation consists of undesirable periodic fluctuations in wear on railway track and costs the railway industry substantially for it's removal by regrinding. Much research has been performed on this problem, particularly over the past two decades, however, a reliable cure remains elusive for wear-type corrugations. Recently the growth behaviour of wear-type rail corrugation-has been investigated using theoretical and experimental models as part of the RailCRC Project (#18). A critical part of this work is the tuning and validation of these models via an extensive field testing program. Rail corrugations have been monitored for 2 years on sites throughout Australia. Measured rail surface profiles are used to determine corrugation growth rates on each site. Growth rates and other characteristics are compared with theoretical predictions from a computer model for validation. The results from several pertinent sites are presented and discussed.
Resumo:
In developed countries travel time savings can account for as much as 80% of the overall benefits arising from transport infrastructure and service improvements. In developing countries they are generally ignored in transport project appraisals, notwithstanding their importance. One of the reasons for ignoring these benefits in the developing countries is that there is insufficient empirical evidence to support the conventional models for valuing travel time where work patterns, particularly of the poor, are diverse and it is difficult to distinguish between work and non-work activities. The exclusion of time saving benefits may lead to a bias against investment decisions that benefit the poor and understate the poverty reduction potential of transport investments in Least Developed Countries (LDCs). This is because the poor undertake most travel and transport by walking and headloading on local roads, tracks and paths and improvements of local infrastructure and services bring large time saving benefits for them through modal shifts. The paper reports on an empirical study to develop a methodology for valuing rural travel time savings in the LDCs. Apart from identifying the theoretical and empirical issues in valuing travel time savings in the LDCs, the paper presents and discusses the results of an analysis of data from Bangladesh. Some of the study findings challenge the conventional wisdom concerning the time saving values. The Bangladesh study suggests that the western concept of dividing travel time savings into working and non-working time savings is broadly valid in the developing country context. The study validates the use of preference methods in valuing non-working time saving values. However, stated preference (SP) method is more appropriate than revealed preference (RP) method.
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The purpose of this paper is to theorise the changes surrounding the introduction of a management control innovation, total quality management (TQM) techniques, within Telecom Fiji Limited. Using institutional theory and drawing on empirical evidence from multiple sources including interviews, discussions and documents, the paper explicates the institutionalization of these TQM practices. The focus of the paper is the micro-processes and practice changes around TQM implementation, rather than the influence of the macro-level structures that are often linked with institutional theory. The change agents used Quality Action Teams and the National Quality Council to introduce new TQM routines. The present study extends the scope of institutional analysis by explaining how institutional contradictions impact to create and make space for institutional entrepreneurs, who in turn, modify existing routines or introduce new routines in fluid organizational environments which also exhibit evidence of resistance.
Resumo:
It has been proposed that language impairments in children with Autism Spectrum Disorders (ASD) stem from atypical neural processing of speech and/or nonspeech sounds. However, the strength of this proposal is compromised by the unreliable outcomes of previous studies of speech and nonspeech processing in ASD. The aim of this study was to determine whether there was an association between poor spoken language and atypical event-related field (ERF) responses to speech and nonspeech sounds in children with ASD (n = 14) and controls (n = 18). Data from this developmental population (ages 6-14) were analysed using a novel combination of methods to maximize the reliability of our findings while taking into consideration the heterogeneity of the ASD population. The results showed that poor spoken language scores were associated with atypical left hemisphere brain responses (200 to 400 ms) to both speech and nonspeech in the ASD group. These data support the idea that some children with ASD may have an immature auditory cortex that affects their ability to process both speech and nonspeech sounds. Their poor speech processing may impair their ability to process the speech of other people, and hence reduce their ability to learn the phonology, syntax, and semantics of their native language.
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The globalization contributes to rapid economic developments and great changes of lifestyle in Madre de Dios of Peru, both of which have influenced the health status of local people in direct and indirect ways. The high overweight and obesity rate has become one of the biggest health challenges in this region. This study quantitatively analyzed the impact of household economic status and food consumption patterns on overweight and obesity, and tried to establish their relationship with local economic activities. People living in mining communities are more likely to be overweight or obese. Increased family incomes and lacks of health knowledge are two important reasons. The large consumption of soda and alcohol are positively associated with overweight and obesity. In addition, lack of physical activities is also one of the risk factors of overweight and obesity.
Resumo:
Endocrine disruption has rarely been reported in field populations of the edible cockle and the context with the general health of the shellfish is unclear. This study examined the reproductive state of two Cerastoderma edule populations over a 6-month period to assess their reproductive condition, the incidence of intersex and presence of parasitic infection. A further seven native sites from south-west England were examined during the peak reproductive season to identify the presence of intersex within the region. Laboratory exposures of organisms collected from field populations showed a significantly female-biased sex ratio compared with controls when exposed to the endocrine disrupting chemicals, bisphenol-A (nominal concentration: 0.1 µg L−1) and 17β-oestradiol (nominal concentration: 0.1 µg L−1), but none of the chemical exposures induced intersex. Intersex was revealed in seven out of the nine native populations of C. edule sampled at peak reproductive season. The highest incidence and most severe case of intersex were reported at Lower Anderton on the River Tamer which also had a significantly female-biased sex ratio. Additionally, the dominant trematode family was the Bucephalaidae. Parasitic infection influences the maturity of C. edule by lowering both mean gonad index and condition index. These results suggest that endocrine disrupting chemicals could be contributing factors towards the development of intersex in C. edule.
Resumo:
Endocrine disruption has rarely been reported in field populations of the edible cockle and the context with the general health of the shellfish is unclear. This study examined the reproductive state of two Cerastoderma edule populations over a 6-month period to assess their reproductive condition, the incidence of intersex and presence of parasitic infection. A further seven native sites from south-west England were examined during the peak reproductive season to identify the presence of intersex within the region. Laboratory exposures of organisms collected from field populations showed a significantly female-biased sex ratio compared with controls when exposed to the endocrine disrupting chemicals, bisphenol-A (nominal concentration: 0.1 µg L−1) and 17β-oestradiol (nominal concentration: 0.1 µg L−1), but none of the chemical exposures induced intersex. Intersex was revealed in seven out of the nine native populations of C. edule sampled at peak reproductive season. The highest incidence and most severe case of intersex were reported at Lower Anderton on the River Tamer which also had a significantly female-biased sex ratio. Additionally, the dominant trematode family was the Bucephalaidae. Parasitic infection influences the maturity of C. edule by lowering both mean gonad index and condition index. These results suggest that endocrine disrupting chemicals could be contributing factors towards the development of intersex in C. edule.
Resumo:
Much management accounting research focuses on design of incentive compensation contracts. A basic assumption in these contracts is that performance-based incentives improve employee performance. This paper reports on a field test of the multi-period incentive effects of a performance-based compensation plan on the sales of a retail establishment. Analysis of panel data for 15 retail outlets over 66 months indicates a sales increase when the plan is implemented, an effect that persists and increases over time. Sales gains are significantly lower in the peak selling season when more temporary workers are employed.
Resumo:
Background: Children with disabilities living in low and middle income countries’ perceptions of participation are not shown in research. These perceptions are important for providing appropriate interventions. Aim: To describe how children aged 8-12 with an intellectual disability living in Ethiopia perceive their situation regarding participation in activities in everyday life. Method: A descriptive design with a quantitative approach was used. The sample was gathered using consecutive sampling. Fifteen structured interviews were conducted, using “Picture my participation,” an instrument under development. Analyses were made using SPSS Statistics and Microsoft Excel. Results: The children perceived that they participated in activities in everyday life. There was a broad variation in the activities the children prioritized as most important. On a group level, they were very involved in these activities. The majority did not experience any barriers to perform these activities. Conclusions: The perceptions of the majority of the children were that they were involved in daily activities. They did not experience any barriers to participation. The results should be read with caution and generalization is not possible, due to the sample characteristics and that the instrument is under development.
Resumo:
The catastrophic event of red tide has happened in the Strait of Hormuz, the Persian Gulf and Gulf of Oman from late summer 2008 to spring 2009. With its devastating effects, the phenomenon shocked all the countries located in the margin of the Persian Gulf and the Gulf of Oman and caused considerable losses to fishery industries, tourism, and tourist and trade economy of the region. In the maritime cruise carried out by the Persian Gulf and Gulf of Oman Ecological Research Institute, field data, including temperature, salinity, chlorophyll-a, dissolved oxygen and algal density were obtained for this research. Satellite information was received from MODIS and MERIS and SeaWiFS sensors. Temperature and surface chlorophyll images were obtained and compared with the field data and data of PROBE model. The results obtained from the present research indicated that with the occurrence of harmful algal blooms (HAB), the Chlorophyll-a and the dissolved oxygen contents increased in the surface water. Maximum algal density was seen in the northern coasts of the Strait of Hormuz. Less concentration of algal density was detected in deep and surface offshore water. Our results show that the occurred algal bloom was the result of seawater temperature drop, water circulation and the adverse environmental pollutions caused by industrial and urban sewages entering the coastal waters in this region of the Persian Gulf ,This red tide phenomenon was started in the Strait of Hormuz and eventually covered about 140,000 km2 of the Persian Gulf and total area of Strait of Hormuz and it survived for 10 months which is a record amongst the occurred algal blooms across the world. Temperature and chlorophyll satellite images were proportionate to the measured values obtained by the field method. This indicates that satellite measurements have acceptable precisions and they can be used in sea monitoring and modeling.
Resumo:
Available information on the larval release rhythms of brachyurans is biased to temperate estuarine species and outcomes resulting from some sort of artificial manipulation of ovigerous females. In this study we applied field methods to describe the larval release rhythms of an assemblage of tropical rocky shore crabs. Sampling the broods of ovigerous females of Pachygrapsus transversus at two different shores indicated a spatially consistent semilunar pattern, with larval release maxima around the full and new moon. Yet, synchronism between populations varied considerably, with the pattern obtained at the site exposed to a lower wave action far more apparent. Breeding cohorts at one of the sampled shores apparently belonged to actual age groups composing the ovigerous population. The data suggest that these breeding groups release their larvae in alternate syzygy periods, responding to a lunar cycle instead of the semilunar pattern observed for the whole population. For the description of shorter-term rhythms, temporal series at hour intervals were obtained by sampling the plankton and confinement boxes where ovigerous females were held. Unexpectedly, diurnal release activity prevailed over nocturnal hatching. Yet, only grapsids living higher on the shore exhibited strong preferences over the diel cycle, with P. transversus releasing their larvae during the day and Geograpsus lividus during the night. The pea crab Dissodactylus crinitichelis, the spider crab Epialtus brasiliensis and a suite of xanthoids undertook considerable releasing activity in both periods. Apart from the commensal pea crab D. crinitichelis, all other taxa revealed tide-related rhythms of larval release, with average estimates of the time of maximum hatching always around the time of high tides; usually during the flooding and slack, rather than the ebbing tide. Data obtained for P. transversus females held in confinement boxes indicated that early larval release is mostly due to nocturnal hatching, while zoeal release in diurnal groups took place at the time of high tide. Since nocturnal high tides at the study area occurred late, sometimes close to dusk, early release would allow more time for offshore transport of larvae when the action of potential predators is reduced.
Resumo:
Background The onsite treatment of sewage and effluent disposal within the premises is widely prevalent in rural and urban fringe areas due to the general unavailability of reticulated wastewater collection systems. Despite the seemingly low technology of the systems, failure is common and in many cases leading to adverse public health and environmental consequences. Therefore it is important that careful consideration is given to the design and location of onsite sewage treatment systems. It requires an understanding of the factors that influence treatment performance. The use of subsurface effluent absorption systems is the most common form of effluent disposal for onsite sewage treatment and particularly for septic tanks. Additionally in the case of septic tanks, a subsurface disposal system is generally an integral component of the sewage treatment process. Therefore location specific factors will play a key role in this context. The project The primary aims of the research project are: • to relate treatment performance of onsite sewage treatment systems to soil conditions at site; • to identify important areas where there is currently a lack of relevant research knowledge and is in need of further investigation. These tasks were undertaken with the objective of facilitating the development of performance based planning and management strategies for onsite sewage treatment. The primary focus of the research project has been on septic tanks. Therefore by implication the investigation has been confined to subsurface soil absorption systems. The design and treatment processes taking place within the septic tank chamber itself did not form a part of the investigation. In the evaluation to be undertaken, the treatment performance of soil absorption systems will be related to the physico-chemical characteristics of the soil. Five broad categories of soil types have been considered for this purpose. The number of systems investigated was based on the proportionate area of urban development within the Brisbane region located on each soil types. In the initial phase of the investigation, though the majority of the systems evaluated were septic tanks, a small number of aerobic wastewater treatment systems (AWTS) were also included. This was primarily to compare the effluent quality of systems employing different generic treatment processes. It is important to note that the number of different types of systems investigated was relatively small. As such this does not permit a statistical analysis to be undertaken of the results obtained. This is an important issue considering the large number of parameters that can influence treatment performance and their wide variability. The report This report is the second in a series of three reports focussing on the performance evaluation of onsite treatment of sewage. The research project was initiated at the request of the Brisbane City Council. The work undertaken included site investigation and testing of sewage effluent and soil samples taken at distances of 1 and 3 m from the effluent disposal area. The project component discussed in the current report formed the basis for the more detailed investigation undertaken subsequently. The outcomes from the initial studies have been discussed, which enabled the identification of factors to be investigated further. Primarily, this report contains the results of the field monitoring program, the initial analysis undertaken and preliminary conclusions. Field study and outcomes Initially commencing with a list of 252 locations in 17 different suburbs, a total of 22 sites in 21 different locations were monitored. These sites were selected based on predetermined criteria. To obtain house owner agreement to participate in the monitoring study was not an easy task. Six of these sites had to be abandoned subsequently due to various reasons. The remaining sites included eight septic systems with subsurface effluent disposal and treating blackwater or combined black and greywater, two sites treating greywater only and six sites with AWTS. In addition to collecting effluent and soil samples from each site, a detailed field investigation including a series of house owner interviews were also undertaken. Significant observations were made during the field investigations. In addition to site specific observations, the general observations include the following: • Most house owners are unaware of the need for regular maintenance. Sludge removal has not been undertaken in any of the septic tanks monitored. Even in the case of aerated wastewater treatment systems, the regular inspections by the supplier is confined only to the treatment system and does not include the effluent disposal system. This is not a satisfactory situation as the investigations revealed. • In the case of separate greywater systems, only one site had a suitably functioning disposal arrangement. The general practice is to employ a garden hose to siphon the greywater for use in surface irrigation of the garden. • In most sites, the soil profile showed significant lateral percolation of effluent. As such, the flow of effluent to surface water bodies is a distinct possibility. • The need to investigate the subsurface condition to a depth greater than what is required for the standard percolation test was clearly evident. On occasion, seemingly permeable soil was found to have an underlying impermeable soil layer or vice versa. The important outcomes from the testing program include the following: • Though effluent treatment is influenced by the physico-chemical characteristics of the soil, it was not possible to distinguish between the treatment performance of different soil types. This leads to the hypothesis that effluent renovation is significantly influenced by the combination of various physico-chemical parameters rather than single parameters. This would make the processes involved strongly site specific. • Generally the improvement in effluent quality appears to take place only within the initial 1 m of travel and without any appreciable improvement thereafter. This relates only to the degree of improvement obtained and does not imply that this quality is satisfactory. This calls into question the value of adopting setback distances from sensitive water bodies. • Use of AWTS for sewage treatment may provide effluent of higher quality suitable for surface disposal. However on the whole, after a 1-3 m of travel through the subsurface, it was not possible to distinguish any significant differences in quality between those originating from septic tanks and AWTS. • In comparison with effluent quality from a conventional wastewater treatment plant, most systems were found to perform satisfactorily with regards to Total Nitrogen. The success rate was much lower in the case of faecal coliforms. However it is important to note that five of the systems exhibited problems with regards to effluent disposal, resulting in surface flow. This could lead to possible contamination of surface water courses. • The ratio of TDS to EC is about 0.42 whilst the optimum recommended value for use of treated effluent for irrigation should be about 0.64. This would mean a higher salt content in the effluent than what is advisable for use in irrigation. A consequence of this would be the accumulation of salts to a concentration harmful to crops or the landscape unless adequate leaching is present. These relatively high EC values are present even in the case of AWTS where surface irrigation of effluent is being undertaken. However it is important to note that this is not an artefact of the treatment process but rather an indication of the quality of the wastewater generated in the household. This clearly indicates the need for further research to evaluate the suitability of various soil types for the surface irrigation of effluent where the TDS/EC ratio is less than 0.64. • Effluent percolating through the subsurface absorption field may travel in the form of dilute pulses. As such the effluent will move through the soil profile forming fronts of elevated parameter levels. • The downward flow of effluent and leaching of the soil profile is evident in the case of podsolic, lithosol and kransozem soils. Lateral flow of effluent is evident in the case of prairie soils. Gleyed podsolic soils indicate poor drainage and ponding of effluent. In the current phase of the research project, a number of chemical indicators such as EC, pH and chloride concentration were employed as indicators to investigate the extent of effluent flow and to understand how soil renovates effluent. The soil profile, especially texture, structure and moisture regime was examined more in an engineering sense to determine the effect of movement of water into and through the soil. However it is not only the physical characteristics, but the chemical characteristics of the soil also play a key role in the effluent renovation process. Therefore in order to understand the complex processes taking place in a subsurface effluent disposal area, it is important that the identified influential parameters are evaluated using soil chemical concepts. Consequently the primary focus of the next phase of the research project will be to identify linkages between various important parameters. The research thus envisaged will help to develop robust criteria for evaluating the performance of subsurface disposal systems.
Resumo:
A largely overlooked aspect of creative design practices is how physical space in design studios plays a role in supporting designers' everyday work. In particular, studio surfaces such as designers' desks, office walls, notice boards, clipboards and drawing boards are full of informative, inspirational and creative artefacts such as, sketches, drawings, posters, story-boards and Post-it notes. Studio surfaces are not just the carriers of information but importantly they are sites of methodic design practices, i.e. they indicate, to an extent, how design is being carried out. This article describes the results of an ethnographic study on the use of workplace surfaces in design studios, from two academic design departments. Using the field study results, the article introduces an idea of ‘artful surfaces’. Artful surfaces emphasise how artfully designers integrate these surfaces into their everyday work and how the organisation of these surfaces comes about helping designers in accomplishing their creative and innovative design practices. Using examples from the field study, the article shows that artful surfaces have both functional and inspirational characteristics. From the field study, three types of artful surfaces are identified: personal; shared; and project-specific. The article suggests that a greater insight into how these artful surfaces are created and used could lead to better design of novel display technologies to support designers' everyday work.