1,656 research outputs found

    Situational reasoning for road driving in an urban environment

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    Robot navigation in urban environments requires situational reasoning. Given the complexity of the environment and the behavior specified by traffic rules, it is necessary to recognize the current situation to impose the correct traffic rules. In an attempt to manage the complexity of the situational reasoning subsystem, this paper describes a finite state machine model to govern the situational reasoning process. The logic state machine and its interaction with the planning system are discussed. The approach was implemented on Alice, Team Caltech’s entry into the 2007 DARPA Urban Challenge. Results from the qualifying rounds are discussed. The approach is validated and the shortcomings of the implementation are identified

    The mature female clothing shopper : profiles and shopping behaviour

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    The original publication is available at http://www.sajip.co.zaCITATION: Visser, E.M., Du Preez, R. & Du Toit, J.B. 1996. The mature female clothing shopper : profiles and shopping behaviour. SA Journal of Industrial Psychology, 22(2):1-6, doi:10.4102/sajip.v22i2.603.This study was designed to profile the mature female clothing shopper. More specifically certain variables that could be attributed to differences in consumer behaviour were investigated. Mature female clothing shoppers were segmented as clothing moderates, clothing enthusiasts and the clothing unconcerned. These three cluster groups significantly differed regarding clothing involvement, clothing orientation, activities, interests, opinions, family orientation, needs and media usage. No significant differences were found among the three groups regarding evaluative criteria for clothing and clothing store attributes. Profiles of the clusters were developed, along with applicable marketing implications. Recommendations for further research are made.Hierdie studie is onderneem ten einde die vroulike kledingverbruikers van 55 en ouer te tipeer. Die veranderlikes wat 'n bydrae kon lewer ten opsigte van die verskille in verbruikersgedrag is ondersoek. Die verbruikers is gesegmenteer as die kledinggematigdes, kleding- entoesiaste en die kleding-onbetrokkenes. Die drie groeperings verskil beduidend van mekaar ten opsigte van die volgende veranderlikes naamlik: kleding-betrokkenheid, kleding-oriëntasie, aktiwiteite belangstellings, opinies, familie oriëntasie, behoeftes en media gebruik. Geen beduidende verskille kon gevind word tussen die drie groeperings ten opsigte van die veranderlikes evalueringskriteria van klere en winkeleienskappe nie. Profiele van die verskillende trosse is ontwikkel en die bemarkingsimplikasies is uitgewys. Aanbevelings vir verdere navorsing word gedoen.Publishers' Versio

    Faecal nematode egg counts in Merino sheep following natural challenge

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    (South African J of Animal Science, 2000, 30, Supplement 1: 24-25

    Malolactic Fermentation: The ABC’s of MLF

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    There are two main fermentations associated with the winemaking process. Alcoholic fermentation is conducted bythe yeast culture and malolactic fermentation takes place as a result of the metabolic activity of lactic acid bacteria,specifically from the genera Oenococcus, Lactobacillus, Pediococcus and Leuconostoc. Malolactic fermentation isdefined as the conversion of malic acid to lactic acid and CO2 and besides deacidification also contributes to microbialstability and modification of the aroma profile. This paper aims to provide a comprehensive review discussing all themain aspects and factors related to malolactic fermentation, including practical considerations for monitoring andensuring a successful fermentation

    DYNAMIC ELUTRIATION MEASUREMENT IN A CONTINUOUSLY OPERATED BUBBLING FLUIDIZED BED

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    Measurements were performed using a novel thermal mass flow meter. The dynamic behaviour of the total elutriation rate was monitored from start-up until a steady rate was achieved. It was found that the elutriation rate at unsteady conditions can be as much as 5 times that of the steady value and that it can take more than an hour to reach steady state. This is attributed to the dynamic changes of the fines distribution between the fluidized bed and dipleg. It was further shown that a steady dipleg height does not indicate steady elutriation rates. Using the flow meter to confirm steady state measurements, elutriation constants were determined for the glass bead - air system at different superficial velocities

    Kinetic simulations of X-B and O-X-B mode conversion

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    We have performed fully-kinetic simulations of X-B and O-X-B mode conversion in one and two dimensional setups using the PIC code EPOCH. We have recovered the linear dispersion relation for electron Bernstein waves by employing relatively low amplitude incoming waves. The setups presented here can be used to study non-linear regimes of X-B and O-X-B mode conversion.Comment: 4 pages, 3 figure

    Genetic analysis of faecal worm egg count in South African Merinos under natural challenge

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    Sheep from a Merino selection experiment at the Tygerhoek research farm in the Southern Cape provided material for this study. The selection lines involved included a line selected for clean fleece weight, a “Wet and Dry” line, a fine wool line and an unselected Control line. Rectal faeces samples were obtained from individual animals at 13 to 16 months of age, after drenching was withheld for at least 10 weeks. Nematode eggs in these samples were counted. Fitting the appropriate fixed effects, the heritability of untransformed, cube root transformed and log transformed faecal nematode egg count (FEC) was obtained from single-trait analyses. The effects of sex and birth year were involved in a significant interaction. Means for FEC were generally higher in ram progeny than in ewes, but the magnitude of the sex difference was not consistent. Multiple lambs had a slightly lower mean for FEC than singles, while FEC was unaffected by dam age. The heritability of FEC was estimated at between 0.14 for untransformed data and 0.18 for log transformed FEC. Genetic correlations of log transformed FEC with two-tooth staple strength (-0.49) and coefficient of variation of fibre diameter (0.30) were favourable. Clean fleece weight was unfavourably related to FEC on a genetic level (0.19). Selection for resistance to parasitic nematodes after natural challenge should thus be feasible in the Merino lines studied. Keywords: Fleece weight; genetic correlation; heritability; live weight; resistance South African Journal of Animal Science Vol. 37 (4) 2007: pp.237-24

    Development and function of the fetal adrenal.

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    The adrenal cortex undergoes multiple structural and functional rearrangements to satisfy the systemic needs for steroids during fetal life, postnatal development, and adulthood. A fully functional adrenal cortex relies on the proper subdivision in regions or 'zones' with distinct but interconnected functions, which evolve from the early embryonic stages to adulthood, and rely on a fine-tuned gene network. In particular, the steroidogenic activity of the fetal adrenal is instrumental in maintaining normal fetal development and growth. Here, we review and discuss the most recent advances in our understanding of embryonic and fetal adrenal development, including the known causes for adrenal dys-/agenesis, and the steroidogenic pathways that link the fetal adrenal with the hormone system of the mother through the fetal-placental unit. Finally, we discuss what we think are the major open questions in the field, including, among others, the impact of osteocalcin, thyroid hormone, and other hormone systems on adrenal development and function, and the reliability of rodents as models of adrenal pathophysiology

    Persistent pain following ankle sprain: Bilateral accessory soleus muscles

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    Persistent pain following ankle sprain remains a difficult diagnostic and management dilemma. We report a 22 year old rugby player who presented with a persistent painful left ankle following a minor ankle sprain. After examination and imaging investigations, a symptomatic accessory soleus muscle was diagnosed on the left ankle, and an asymptomatic accessory soleus muscle on the right

    A 10-year analysis of organ donor referrals to a South African tertiary public sector hospital

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    Background. South Africa (SA) has one of the lowest deceased organ donor rates in the world (1.4 donors per million population), with thousands of patients awaiting solid-organ transplantation. In order to improve access to transplantation we have to clearly define the reasons for the low deceased donation rate, specific to the population we serve.Objectives. Review of actual donor statistics highlights our successes, yet is not able to contextualise the factors responsible for the unsuccessful conversion of referred organ donors to actual organ donors. In an attempt to identify key factors preventing referred donors from becoming actual donors, we analysed the donor referral patterns at our institution over a 10-year period.Methods. This was a retrospective descriptive study of consecutive deceased donor referrals at Groote Schuur Hospital, Cape Town, SA (from January 2007 to December 2016), utilising a regional donor referral registry. Qualitative and quantitative data were collected and presented as descriptive statistics and temporal trends.Results. Over the 10-year study period, 861 possible organ donors were referred, with a steady increase in the number of referrals over time. Of the referrals, 514 (59.7%) were eligible for donation of at least one solid organ. Of the 508 families that were approached for consent to donation, 342 declined consent for a variety of reasons, resulting in a consent rate of 32.7%. Ultimately, at least one solid organ was obtained from 159 of the 166 consented donors. Despite the increasing number of possible and eligible donors, a statistically significant decline in consent rate was observed over time (ptrend=0.023). Furthermore, increasing trends in medical (as opposed to trauma) (ptrend<0.001) and extended criteria (as opposed to standard criteria) donor referrals (ptrend<0.001) were observed over the 10-year study period.Conclusions. Donor referral patterns have changed over time, with a notable increase in medical and extended criteria donors. Despite the increase in possible and eligible donors, the consent rate has declined. Further qualitative and quantitative research studies are required to understand and address this trend.
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