15,788 research outputs found
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Measuring cycle riding comfort in Southampton using an instrumented bicycle
The increased environmental awareness and the rising fuel costs make bicycles a more and more attractive mode of travel for short journeys. Considering the future prospect of this mode of transportation and the great advantages that it offers in terms of space consumption, health and environmental sustainability, several city authorities worldwide are presently undertaking schemes aiming at improving cycling infrastructure. The aim of the present study is to monitor the impact of such schemes on the riding comfort of cyclists, as expressed by the, usually lower, quantity and magnitude of vibrations occurring as a result of cycling over pavement defects. Millbrook Road East in the western edge of the city center of Southampton is used as a case study, where vibration measurements are taken by means of an instrumented bicycle during periods before and after a redevelopment scheme involving the resurfacing of the road pavement. The results show a clear overall improvement in cycling comfort post-redevelopment, with statistically significant reductions in both the number of high severity vibrations and of their magnitude in "typical" cycling trips taken on the road. However, instances of finishing "snags" in some parts of the surface appear to introduce new minor defects (e.g. around manholes) that are not visible to the naked eye, and these still have some negative effect on the riding experience. Moreover, the study highlights the detrimental impact that widespread pavement defects can have on riding comfort, which affect cyclists of all ages, abilities and styles
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A Talk on the Wild Side: The Direct and Indirect Impact of Speech Recognition on Learning Gains
Research in the learning sciences and mathematics education has suggested that āthinking aloudā (verbalization) can be important for learning. In a technology-mediated learning environment, speech might also help to promote learning by enabling the system to infer the studentsā cognitive and affective state so that they can be provided a
sequence of tasks and formative feedback, both of which are adapted to their needs. For these and associated reasons, we developed the iTalk2Learn platform that includes speech production and speech recognition for children learning about fractions. We investigated the impact of iTalk2Learnās speech functionality in classrooms in the UK and Germany, with our results indicating that a speech-enabled learning environment has the potential to enhance student learning gains and engagement, both directly and indirectly
Rumen function and digestion parameters associated with differences between sheep in methane emissions when fed chaffed lucerne hay
An indoor experiment involving 10 rumen-cannulated Romney sheep was conducted in May and June 1998 at AgResearch Grasslands, Palmerston North, New Zealand, under restricted feeding conditions. in order to test the hypothesis that animal factors, in particular rumen fractional outflow rate (FOR) and rumen volume, have an influence on the between-sheep variation in methane (CH4) emission. Sheep were fed 2-hourly on chaffed lucerne hay. Following an acclimatization period of 21 days, the experiment lasted 16 days. Energy and nitrogen (N) balances were measured on days 1-6. Cr-EDTA marker was continuously infused into the rumen from day 9 to 16, and rumen contents emptied and sampled on days 13 and 16. Particulate and fluid FOR were estimated using feed lignin and Cr-EDTA, respectively. Daily CH, production was measured by the sulphur hexafluoride tracer technique on days 2, 5, 6, 12 and 15 of the experiment.
CH4 production (g/day) was positively correlated with the pool size of organic matter (OM) in the rumen (OM pool, g) (r = 0.84, P = 0.002), OM intake (OMI, g/day) (r = 0.67, P = 0.04), and the rumen fill (g. wet digesta) (r = 0.76, P = 0.01). Multiple regression analysis showed that CH4 production was best predicted (R-2 = 0.88) as a function of OM pool and the molar % of butyrate; however, OM pool alone accounted for a large proportion (R-2 = 0.71) of the variation in CH4 production.
CH4 yield (% gross energy intake, % GEI) was negatively correlated with the particulate FOR (%/h) ( r= -0.75, P = 0.01) and buffering capacity of rumen fluid (mmol HCl) (r = -0.72, P = 0.02) but positively correlated with the digestibility of cellulose (r = 0.66, P = 0.04). Multiple regression analysis showed that CH, yield was best predicted as a function of particulate FOR, OMI (g/kg liveweight(0.75)) and the molar % of butyrate (R-2 = 0.88). Particulate FOR alone explained a large proportion (R-2 = 0.57) of the variation in CH4 Yield. Particulate FOR was negatively correlated with rumen fill (r = -0.69, P = 0.03) and digestibility of cellulose (r = -0.65, P = 0.04).
These results suggest that sheep with lower rumen particulate FOR (i.e. longer rumen retention times) had larger rumen fills and higher fibre digestibilities and CH4 yields. If rumen particulate FOR is to be used as a tool for CH4 mitigation, the repeatability of its relationship to CH4 emission must be assessed, preferably under grazing conditions
Persistence of differences between sheep in methane emission under generous grazing conditions
Four low and four high methane (CH4) emitters were selected from a flock of 20 Romney sheep on the basis of CH4 production rates per unit of intake, measured at grazing using the sulphur hexafluoride (SF,) tracer technique. Methane emissions from these sheep were monitored at grazing for four periods (P): October, November, January and February 1999/2000. All measurements were carried out on perennial ryegrass/white clover pasture under generous herbage allowance, and the sheep were maintained on similar pastures during non-measurement periods. The tracer technique was used for all the CH4 measurements and feed DM intake was calculated from total faecal collection and estimated DM digestibility. Data for liveweight (LW), gross energy intake (GEI) and CH4 emission were analysed using split-plot analysis of variance. In addition, a between-period rank order correlation analysis was carried out for CH4 emission data.
Low CH4 emitters were heavier (P < 0.05) than the high emitters in all the periods, but they did not differ (P < 0.05) in their gross energy intakes (GEL MJ/kg LW0.75). Low and high CH4 emitters consistently maintained their initial rankings in CH4 yield (% GEI) throughout the subsequent periods and the correlation analysis of rank order for CH4 yield showed strong between-period correlation coefficients, although this was weaker in the last period. It is suggested that feeding conditions that maximize feed intake (e.g. generous allowance of good quality pasture under grazing) favour the expression and persistence of between-sheep differences in CH4 yield
Feeding of Conserved Forage - Implications to Grassland Management and Production
This review will focus on the use of conserved forages in pastoral dairy farm systems; especially on their conservation as an aid to good grazing management during periods of rapid pasture growth, and on their consumption as an aid to good feeding management and grazing management during periods of slow pasture growth. Conservation of pasture, in order to move it from one time to another later time, always involves ācostsā, either financial expenditure or physical losses (of dry matter/quality) or both, which must be evaluated in the whole system.
Most of the data is drawn from New Zealand and Australia, with some from England and Ireland. The topic has been reviewed before (e.g. Rogers, 1984 and 1985; Leaver, 1985; Phillips, 1988; Mayne, 1991; Stockdale et al., 1997), but the present review will put greater emphasis on the effects on pasture management and on the whole pastoral system, and on recent results, because the cowsā ability to respond to supplementary feeds is now larger than it used to be, as a result of steady genetic improvement in milk producing capacities. In recent years there has been marked increase in supplement use on pasture based dairy farming systems in New Zealand often driven by perceived limitations to production increases in existing systems rather than profit (Attrill and Miller 1996). This review attempts to identify, and discuss, the factors involved in supplementary feeding (i.e. the responses of cows and farming systems to extra feed) to enable sustainable increases in productivity and profitability on pastoral based systems
Predicting prognosis in lung cancer: Use of proliferation marker, Ki67 monoclonal antibody
An investigation was carried out to assess the prognostic significance of proliferation marker Ki67 in a group of lung cancer patients treated by surgery (limited disease). Tissue was not available for Ki67 immunostaining in inoperable group. The diagnosis is established by bronchial biopsy which does not carry enough tissue for frozen section and counting. This study is supplemented by estimating the prognostic significance of histological sub-types in the operable group and in a group of inoperable patients with extensive disease. These are usually treated by radiotherapy and/or chemotherapy. In all, 267 patients were studied including 105 treated by surgery. These patients attended King\u27s College and Brompton Hospital, UK, between 1986 and 1989. With regard to proliferation marker Ki67 done for the surgical group, only patients with Ki67 scores of less than 5% did survive significantly longer than the rest. Histology did not make any significant contribution in determining prognosis in both operable and inoperable groups. Although follow-up is limited (mean 20 months), Ki67 antibody seems promising in identifying low and high grade disease in the initial stage of lung cancer. It may prove useful for category of patients with high scores to be placed on chemotherapy/radiotherapy. Results suggest that in the case of lung tumour, proliferative activity is a better prognostic indicator than histological type
Methane emission by alpaca and sheep fed on lucerne hay or grazed on pastures of perennial ryegrass/white clover or birdsfoot trefoil
Based on the knowledge that alpaca (Lama pacos) have a lower fractional outflow rate of feed particles (particulate FOR) from their forestomach than sheep (San Martin 1987), the current study measured methane (CH4) production and other digestion parameters in these species in three successive experiments (1, 2 and 3): Experiment 1, lucerne hay fed indoors; Experiment 2, grazed on perennial ryegrass/white clover pasture (PRG/WC); and Experiment 3, grazed on birdsfoot trefoil (Lotus corniculatits) pasture (Lotus). Six male alpaca and six castrated Romney sheep were simultaneously and successively fed on the forages either ad libitium or at generous herbage allowances (grazing). CH4 production (g/day) (using the sulphur hexafluoride tracer technique), voluntary feed intake (VFI), diet quality, and protozoa counts and volatile fatty acid concentrations in samples of forestomach contents were determined. In addition, feed digestibility, energy and nitrogen (N) balances and microbial N supply from the forestomach (using purine derivatives excretion) were measured in Experiment 1.
Diets selected by alpaca were of lower quality than those selected by sheep, and the voluntary gross energy intakes (GEI, MJ) per kg of liveweight(0.75) were consistently lower (P0.05) in their CH4 yields (% GEI) when fed on lucerne hay (5.1 v. 4.7), but alpaca had a higher CH4 yield when fed on PRG/WC (9.4 v. 7.5, P0.05) in diet N partition or microbial N yield, but alpaca had higher (P<0.05) neutral detergent fibre digestibility (0.478 v. 0.461) and lower (P<0.01) urinary energy losses (5.2 v. 5.8 % GEI) than sheep. It is suggested that differences between these species in forestomach particulate FOR might have been the underlying physiological mechanism responsible for the differences in CH4 yield, although the between-species differences in VFI and diet quality also had a major effect on it
Interaction patterns in exploratory learning environments for mathematics: a sequential analysis of feedback and external representations in Chinese schools
Feedback in exploratory learning systems has been depicted as an important contributor to encourage exploration. However, few studies have explored learnersā interaction patterns associated with feedback and the use of external representations in exploratory learning environments. This study used Fractions Lab, an exploratory learning environment for mathematics, to facilitate childrenās conceptual understanding of fractions in three Chinese schools. Students (nā=ā189) from six different classes were invited to use Fractions Lab, and 260,000 event logs were collected. Beyond demonstrating the overall efficacy of the approach, lag sequential analysis supported us in approaching a deeper understanding of patterns of interaction. The findings highlight that the design of three-levels of feedback (Socratic, guidance, and didactic-procedural feedback) played different roles in supporting students to use external representations to perform mathematical tasks in an exploratory learning environment. This study sheds light on how these interaction patterns might be applied to the Fractions Lab system in order to provide increasingly tailored support, based on cultural differences, to enhance studentsā technology-mediated learning experiences
A single amino acid change in Escherichia coli glycerol kinase abolishes glucose control of glycerol utilization in vivo.
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