Situational reasoning for road driving in an urban environment

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

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

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

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

Continuous renal replacement therapy: current practice in Australian and New Zealand intensive care units

BACKGROUND: Large multicentre studies of continuous renal replacement therapy (CRRT) in critically ill patients may influence its bedside prescription and practical application. Despite this, many aspects of CRRT may not be informed by evidence but remain a product of clinician preference. Little was known about current CRRT practice in Australia and New Zealand and it is not known if the evidence from recent studies has been integrated into practice. DESIGN AND SETTING: A prospective online survey of CRRT practice was sent to intensive care unit medical and nursing clinicians via three national databases in Australian and New Zealand ICUs in December 2013 to March 2014. RESULTS: There were 194 respondents from 106 ICUs; 49 ICUs (47%) were in tertiary metropolitan hospitals. One hundred and two respondents (54%) reported continuous venovenous haemodiafiltration as the most common CRRT technique, with a combination of predilution and postdilution of CRRT solutions. The prescription for CRRT was variable, with respondents indicating preferences for therapy based on L/hour (53%) or a weight-adjusted treatment in mL/kg/hour (47%). For all modes of CRRT, the common blood flow rates applied were 151-200mL/ minute and 201-250mL/minute. Few respondents reported preferring flow rates < 150 mL/minute or > 300mL/minute. Unfractionated heparin was the most commonly used anticoagulant (83%), followed by regional citrate. Femoral vein vascular access was preferred and, typically, a 20 cm length catheter was used. Bard Niagara and Arrow catheters were most frequently used. The Gambro Prismaflex was the dominant machine used (71%). CONCLUSIONS: Our results provide insight into existing clinical management of CRRT. There is considerable variation in the prescription of CRRT in Australian and New Zealand ICUs

Faster Blood Flow Rate Does Not Improve Circuit Life in Continuous Renal Replacement Therapy: A Randomized Controlled Trial

Objectives: To determine whether blood flow rate influences circuit life in continuous renal replacement therapy. Design: Prospective randomized controlled trial. Setting: Single center tertiary level ICU. Patients: Critically ill adults requiring continuous renal replacement therapy. Interventions: Patients were randomized to receive one of two blood flow rates: 150 or 250 mL/min. Measurements and Main Results: The primary outcome was circuit life measured in hours. Circuit and patient data were collected until each circuit clotted or was ceased electively for nonclotting reasons. Data for clotted circuits are presented as median (interquartile range) and compared using the Mann-Whitney U test. Survival probability for clotted circuits was compared using log-rank test. Circuit clotting data were analyzed for repeated events using hazards ratio. One hundred patients were randomized with 96 completing the study (150 mL/min, n = 49; 250 mL/min, n = 47) using 462 circuits (245 run at 150 mL/min and 217 run at 250 mL/min). Median circuit life for first circuit (clotted) was similar for both groups (150 mL/min: 9.1 hr [5.5–26 hr] vs 10 hr [4.2–17 hr]; p = 0.37). Continuous renal replacement therapy using blood flow rate set at 250 mL/min was not more likely to cause clotting compared with 150 mL/min (hazards ratio, 1.00 [0.60–1.69]; p = 0.68). Gender, body mass index, weight, vascular access type, length, site, and mode of continuous renal replacement therapy or international normalized ratio had no effect on clotting risk. Continuous renal replacement therapy without anticoagulation was more likely to cause clotting compared with use of heparin strategies (hazards ratio, 1.62; p = 0.003). Longer activated partial thromboplastin time (hazards ratio, 0.98; p = 0.002) and decreased platelet count (hazards ratio, 1.19; p = 0.03) were associated with a reduced likelihood of circuit clotting. Conclusions: There was no difference in circuit life whether using blood flow rates of 250 or 150 mL/min during continuous renal replacement therapy

Evaluation of Urea and Creatinine change during Continuous Renal Replacement Therapy: Effect of blood flow rate

OBJECTIVE: To determine if faster blood flow rate (BFR) has an effect on solute maintenance in continuous renal replacement therapy. DESIGN: Prospective randomised controlled trial. SETTING: 24-bed, single centre, tertiary level intensive care unit. PARTICIPANTS: Critically ill adults requiring continuous renal replacement therapy (CRRT). INTERVENTIONS: Patients were randomised to receive one of two BFRs: 150 mL/min or 250 mL/min. MAIN OUTCOME MEASURES: Changes in urea and creatinine concentrations (percentage change from baseline) and delivered treatment for each 12-hour period were used to assess solute maintenance. RESULTS: 100 patients were randomised, with 96 completing the study (49 patients, 150 mL/min; 47 patients, 250 mL/min). There were a total of 854 12-hour periods (421 periods, 150 mL/min; 433 periods, 250 mL/ min). Mean hours of treatment per 12 hours was 6.3 hours (standard deviation [SD], 3.7) in the 150 mL/min group, and 6.7 hours (SD, 3.9) in the 250 mL/min group (P = 0.6). There was no difference between the two BFR groups for change in mean urea concentration (150 mL/min group, –0.06%; SD, 0.015; v 250 mL/min group, –0.07%; SD, 0.01; P = 0.42) or change in mean creatinine concentration (150 mL/min, –0.05%; SD, 0.01; v 250 mL/min, –0.08%; SD, 0.01; P = 0.18). Independent variables associated with a reduced percentage change in mean serum urea and creatinine concentrations were low haemoglobin levels (–0.01%; SD, 0.005; P = 0.002; and 0.01%; SD, 0.005; P = 0.006, respectively) and less hours treated (–0.023%; SD, 0.001; P = 0.000; and –0.02%; SD, 0.002; P = 0.001, respectively). No effect for bodyweight was found. CONCLUSIONS: Faster BFR did not affect solute control in patients receiving CRRT; however, differences in urea and creatinine concentrations were influenced by serum haemoglobin and hours of treatment

Comparing laboratory costs of smear/culture and Xpert(®) MTB/RIF-based tuberculosis diagnostic algorithms

SETTING: Cape Town, South Africa, where Xpert® MTB/RIF was introduced as a screening test for all presumptive tuberculosis (TB) cases. OBJECTIVE: To compare laboratory costs of smear/culture- and Xpert-based tuberculosis (TB) diagnostic algorithms in routine operational conditions. METHODS: Economic costing was undertaken from a laboratory perspective, using an ingredients-based costing approach. Cost allocation was based on reviews of standard operating procedures and laboratory records, timing of test procedures, measurement of laboratory areas and manager interviews. We analysed laboratory test data to assess overall costs and cost per pulmonary TB and multidrug-resistant TB (MDR-TB) case diagnosed. Costs were expressed as 2013 Consumer Price Index-adjusted values. RESULTS: Total TB diagnostic costs increased by 43%, from US$440 967 in the smear/culture-based algorithm (April–June 2011) to US$632 262 in the Xpert-based algorithm (April–June 2013). The cost per TB case diagnosed increased by 157%, from US$48.77 (n = 1601) to US$125.32 (n = 1281). The total cost per MDR-TB case diagnosed was similar, at US$190.14 and US$183.86, with 95 and 107 cases diagnosed in the respective algorithms. CONCLUSION: The introduction of the Xpert-based algorithm resulted in substantial cost increases. This was not matched by the expected increase in TB diagnostic efficacy, calling into question the sustainability of this expensive new technology

Comparing multidrug-resistant tuberculosis patient costs under molecular diagnostic algorithms in South Africa

SETTING: Ten primary health care facilities in Cape Town, South Africa, 2010–2013. OBJECTIVE: A comparison of costs incurred by patients in GenoType® MDRTBplus line-probe assay (LPA) and Xpert® MTB/RIF-based diagnostic algorithms from symptom onset until treatment initiation for multidrug-resistant tuberculosis (MDR-TB). METHODS: Eligible patients identified from laboratory and facility records were interviewed 3–6 months after treatment initiation and a cost questionnaire completed. Direct and indirect costs, individual and household income, loss of individual income and change in household income were recorded in local currency, adjusted to 2013 costs and converted to $US. RESULTS: Median number of visits to initiation of MDR-TB treatment was reduced from 20 to 7 (P < 0.001) and median costs fell from US$68.1 to US$38.3 (P = 0.004) in the Xpert group. From symptom onset to being interviewed, the proportion of unemployed increased from 39% to 73% in the LPA group (P < 0.001) and from 53% to 89% in the Xpert group (P < 0.001). Median household income decreased by 16% in the LPA group and by 13% in the Xpert group. CONCLUSION: The introduction of an Xpert-based algorithm brought relief by reducing the costs incurred by patients, but loss of employment and income persist. Patients require support to mitigate this impact