Temperature and Humidity Stability of Fibre Optic Sensor Cables for High Resolution Measurements.

Fibre optic sensors offer a means for the real-time continuous measurement of temperature or strain in concrete structures. Backscattered light along a fibre optic sensing (FOS) cable is interrogated to record a frequency shift and this shift is typically translated into a physical parameter such as strain or temperature using a calibration factor. However, when the measured frequency shift is a response to a combination of mechanical, thermal or hygral (humidity) loadings it is difficult to decouple individual influences. This presents a challenge in complex materials such as concrete where the strain, temperature and moisture levels change concurrently during the fresh and hardened states. Furthermore, depending on the application, both short- and longer-term measurements are required. As such, not only is the influence of these physical factors of interest but also the time and spatial stability of the measured frequency, which is highly dependent on the FOS cable composition. To investigate this aspect, fibre optic cables commonly used for strain (three tight-buffered cables) or temperature (two loose-buffered cables) measurement were considered. The cables were subjected to mechanical or environmental exposure and interrogated using a high-resolution optical backscatter reflectometer. The exposure regimes included three temperature cycles with sustained steps from 10 °C to 60 °C and back to 10 °C and an increasing and decreasing humidity cycle with steps between 30 to 90% relH. These ranges were selected to be indicative of typical environments for concrete. The results showed that the calibration factors back-calculated from increasing and decreasing temperature or humidity cycles differed. The third temperature cycle results were found to exhibit the smallest differences between heating and cooling suggesting that temperature pre-conditioning prior to installation could be advantageous. For all the cables, a drift in the readings was observed over the duration (2.5 h for temperature and 30 h for moisture) of the sustained steps. The magnitude of the drift depended on the cable type and exposure condition. In addition, local frequency fluctuations along the cable were observed which would need to be taken into account if only a single point along the cable length was used for analysis. The obtained results highlight the importance of the cable selection to maximise the FOS measurement fidelity for a given parameter of interest.

Parametric Design Studies of Mass-Related Global Warming Potential and Construction Costs of FRP-Reinforced Concrete Infrastructure.

Fibre-reinforced polymers (FRPs) are a promising corrosion-resistant alternative to steel reinforcement. FRPs are, however, generally costly and have a high energy demand during production. The question arises whether the high performance of FRPs and possible savings in concrete mass can counterbalance initial costs and environmental impact. In this paper, a parametric design study that considers a broad range of concrete infrastructure, namely a rail platform barrier, a retaining wall and a bridge, is conducted to assess the mass-related global warming potential and material costs. Design equations are parametrised to derive optimum reinforced concrete cross-sectional designs that fulfil the stated requirements for the serviceability limit state and ultimate limit state. Conventional steel reinforcement, glass and carbon FRP reinforcement options are evaluated. It is observed that the cross-sectional design has a significant influence on the environmental impact and cost, with local extrema for both categories determinable when the respective values become a minimum. When comparing the cradle-to-gate impact of the different materials, the fibre-reinforced polymer-reinforced structures are found to provide roughly equivalent or, in some cases, slightly more sustainable solutions than steel-reinforced structures in terms of the global warming potential, but the material costs are higher. In general, the size of the structure determines the cost competitiveness and sustainability of the FRP-reinforced concrete options with the rail platform barrier application showing the greatest potential.

Speech and Language Disorders in Kenyan Children: Adapting Tools For Regions With Few Assessment Resources.

This study sought to adapt a battery of Western speech and language assessment tools to a rural Kenyan setting. The tool was developed for children whose first language was KiGiryama, a Bantu language. A total of 539 Kenyan children (males=271, females=268, ethnicity=100% Kigiryama. Data were collected from 303 children admitted to hospital with severe malaria and 206 age-matched children recruited from the village communities. The language assessments were based upon the Content, Form and Use (C/F/U) model. The assessment was based upon the adapted versions of the Peabody Picture Vocabulary Test, Test for the Reception of Grammar, Renfrew Action Picture Test, Pragmatics Profile of Everyday Communication Skills in Children, Test of Word Finding and language specific tests of lexical semantics, higher level language. Preliminary measures of construct validity suggested that the theoretical assumptions behind the construction of the assessments were appropriate and re-test and inter-rater reliability scores were acceptable. These findings illustrate the potential to adapt Western speech and language assessments in other languages and settings, particularly those in which there is a paucity of standardised tools.

Evaluating standards in cross-language research: a critique of Squires' criteria.

Innovative methods to conduct cross-language research continue to evolve. There is a need to evaluate the processes involved in cross-language research to assess the extent to which they are fit for purpose from an epistemological point of view, and the subsequent impact on quality of resultant findings. Debate continues about the application of evaluative criteria to qualitative research, not least because of the multiplicity of worldviews and perspectives associated with different qualitative research paradigms. In this article we use two of the authors' studies to discuss how we assess whether methodologies underpinning cross-language research and the choice of methods used are 'fit for purpose'. We use Squires' (2009) 14 criteria to evaluate cross-language nursing and health sciences research based around conceptual equivalence, translator credentials, translator role/competence and study methods, and consider their value as an heuristic or a guide to encourage reflexivity and fuller accounting of the justifications for the approaches taken.

Severe falciparum malaria and acquired childhood language disorder.

Language disorders have been reported after severe falciparum malaria but the deficits have not been described in detail. We assessed language outcome in three groups of children aged 6 to 9 years (n=487): those previously admitted to Kilifi District Hospital, Kenya, with cerebral malaria (CM; n=152; mean age 7y 4 mo [SD 1y 1mo]; 77 males, 75 females); or those with malaria and complicated seizures (M/S; n=156; mean age 7y 4mo [SD 1y 2mo]; 72 males, 84 females); and those unexposed to either condition (n=179; mean age 7y 6mo [SD 1y 1mo]; 93 males, 86 females). Median age at hospital admission was 28 months (interquartile range [IQR] 19 to 44 mo) among children with a history of CM and 23 months (IQR 12 to 35mo) among children with a history of M/S. A battery of eight assessments covering the major facets of speech and language was used to measure language performance. Cognitive performance, neurological/motor skills, behaviour, hearing, and vision were also measured. Eighteen (11.8%) of the CM group, 14 (9%) of the M/S group, and four (2.2%) of the unexposed group were found to have a language impairment. CM (odds ratio 3.68, 95% confidence interval 1.09 to 12.4, p=0.04) was associated with significantly increased odds of an impairment-level score relative to the unexposed group. The results suggest that falciparum malaria is one of the most common causes of acquired language disorders in the tropics.

Issues in the development of cross-cultural assessments of speech and language for children.

BACKGROUND: There is an increasing demand for the assessment of speech and language in clinical and research situations in countries where there are few assessment resources. Due to the nature of cultural variation and the potential for cultural bias, new assessment tools need to be developed or existing tools require adaptation. However, there are few guidelines on how to develop 'culturally appropriate' assessment tools. AIMS: To review the literature on cross-cultural assessment in order to identify the major issues in the development and adaptation of speech and language assessments for children and to illustrate these issues with practical examples from our own research programme in Kenya. METHODS & PROCEDURES: Five broad categories pertaining to cross-cultural assessment development were identified: the influence of culture on performance, familiarity with the testing situation, the effect of formal education, language issues and picture recognition. It was outlined how some of these issues were addressed in our research. The results of the review were integrated to produce a list of ten guidelines highlighting the importance of collaboration with mother tongue speakers; piloting; familiar assessment materials; assessment location; and practice items and prompts. CONCLUSIONS: There are few clinicians and assessors, whether in the UK or abroad, who do not assess or treat children from a culture different to their own. Awareness of cultural variation and bias and cooperative efforts to develop and administer culturally appropriate assessment tools are the foundation of effective, valid treatment programmes.

Developmental impairments following severe falciparum malaria in children.

OBJECTIVE: Neurological deficits are reported in children after cerebral malaria (CM) but little is known about the prevalence and characteristics of persisting neurocognitive consequences. The prevalence of developmental impairments following other complications of falciparum malaria, such as multiple, prolonged or focal seizures, is not known. Thus, our objective was to investigate the long-term developmental outcome of CM and malaria with complicated seizures (M/S). METHODS: We followed up a cohort of children previously exposed to CM or M/S and children unexposed to either condition. All children between 6 and 9 years of age, exposed to CM, and an equal number of children exposed to M/S were identified from databases of hospital admissions from 1991 to 1998. The unexposed group was randomly selected from a census database. The children's performance was measured using assessments of cognition, motor, speech and language, hearing and vision. A parental questionnaire was used to identify children with epilepsy. RESULTS: CM group scores were significantly lower than unexposed group scores on the assessments of higher level language (adjusted mean difference -1.63, 95% CI: -2.99 to -0.27), vocabulary (-0.02, 95% CI: -0.04 to -0.01), pragmatics (OR 2.81, 95% CI: 1.04-7.6) and non-verbal functioning (-0.33, 95% CI: -0.61 to -0.06). The areas of significantly reduced functioning for the M/S group were concentrated on phonology (OR 2.74, 95% CI: 1.26-5.95), pragmatics (OR 3.23, 95% CI: 1.2-8.71) and behaviour (OR 1.8, 95% CI: 1.0-3.23). The performance of the active epilepsy group was significantly poorer than that of the group without epilepsy on the tests of comprehension, syntax, pragmatics, word finding, memory, attention, behaviour and motor skills. CONCLUSIONS: CM and M/S are associated with developmental impairments. If these impairments persist, this may have implications for least 250,000 children in Sub-Saharan Africa each year. Active epilepsy significantly increases the risk of cognitive and behavioural problems in children with a history of severe malaria.