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Substantial Cost (substantial + cost)
Selected AbstractsEffects of Mixing Granular Iron with Sand on the Kinetics of Trichloroethylene ReductionGROUND WATER MONITORING & REMEDIATION, Issue 2 2009Erping Bi A substantial cost of granular iron permeable reactive barriers is that of the granular iron itself. Cutting the iron with sand can reduce costs, but several performance issues arise. In particular, reaction rates are expected to decline as the percentage of iron in the blend is diminished. This might occur simply as a function of iron content, or mass transfer effects may play a role in a much less predictable fashion. Column experiments were conducted to investigate the performance consequences of mixing Connelly granular iron with sand using the reduction kinetics of trichloroethylene (TCE) to quantify the changes. Five mixing ratios (i.e., 100%, 85%, 75%, 50%, and 25% of iron by weight) were studied. The experimental data showed that there is a noticeable decrease in the reaction rate when the content of sand is 25% by weight (iron mass to pore volume ratio, Fe/Vp = 3548 g/L) or greater. An analysis of the reaction kinetics, using the Langmuir-Hinshelwood rate equation, indicated that mass transfer became an apparent cause of rate loss when the iron content fell below 50% by weight (Fe/Vp = 2223 g/L). Paradoxically, there were tentative indications that TCE removal rates were higher in a 15% sand + 85% iron mixture (Fe/Vp = 4416 g/L) than they were in 100% iron (Fe/Vp = 4577 g/L). This subtle improvement in performance might be due to an increase of iron surface available for contact with TCE, due to grain packing in the sand-iron mixture. [source] Cost-utility analysis of Canadian tailored prophylaxis, primary prophylaxis and on-demand therapy in young children with severe haemophilia AHAEMOPHILIA, Issue 4 2008N. RISEBROUGH Summary. Primary prophylaxis is the emerging standard treatment for boys with severe haemophilia. Tailored (escalating-dose) prophylaxis (EscDose), beginning at a low frequency and escalating with repeated bleeding may prevent arthropathy at a lower cost than standard prophylaxis (SP). From a societal perspective, we compared the incremental cost per joint-haemorrhage that is avoided and quality-adjusted-life-year (QALY) gained of SP and EscDose to on-demand (Demand) therapy in severe haemophilia A boys treated to age 6 using a decision analytic model. Costs included factor VIII (FVIII), professional visits and tests, central venous placement/complications, hospitalization, home programmes and parents' lost work-days. Resource utilization was estimated by surveying 17 Canadian clinics. The natural history of bleeding and other probabilities were determined from a longitudinal chart review (n = 24) and published literature. EscDose costs an additional $3192 per joint-haemorrhage that was avoided compared with Demand whereas SP costs an additional $9046 per joint-haemorrhage that was avoided compared with EscDose. Clinic costs and lost wages were reduced by 60,80% for EscDose and SP compared with Demand. EscDose attained more QALYs than SP and Demand on account of less bleeding than Demand and lower need for ports than SP. The incremental cost per QALY for EscDose vs. Demand was $542 938. EscDose was less expensive with similar QALYs compared to SP. Sensitivity analysis was performed on all probability- and cost-estimates, and showed the model was sensitive to the cost of FVIII and the SP and target joint utilities. In conclusion, prophylaxis will substantially improve clinical outcomes and quality of life compared to Demand treatment, but with substantial cost. [source] Daily energy expenditure of singing great reed warblers Acrocephalus arundinaceusJOURNAL OF AVIAN BIOLOGY, Issue 4 2008Dennis Hasselquist According to honest signalling theory, signals must be costly to produce to retain information about the signaller's quality. The song produced by male birds during breeding is a vocal "ornament" used for intra- and inter-sexual purposes. The energetic cost of this vocal signal remains a contentious issue. We used the doubly labelled water method to measure field metabolic rate by estimating CO2 production and then convert this to daily energy expenditure (DEE) in great reed warbler males singing under natural conditions (10 at low to moderate intensity and 7 at very high intensity from dawn to dusk). There was a significant positive relationship between singing intensity and DEE. From this relationship we extrapolated the average DEE for intensely singing males (i.e., males producing song sounds 50% of the time and hence sitting at their elevated song post in the top of a reed stem more or less continuously throughout the ,20 h of daylight) to 3.3×BMR (basal metabolic rate) and for non-singing males to 2.2×BMR. The mean DEE measured for the seven males singing with very high intensity was 3.1×BMR. The maximum measured DEE for a single male was 3.9×BMR, i.e. close to the maximum sustainable DEE (4×BMR), and the minimum DEE was 2.1×BMR for a male singing at very low intensity. These results imply that producing intensive advertising song in birds may incur a substantial cost in terms of increased energy expenditure. [source] Ease and effectiveness of costly autotomy vary with predation intensity among lizard populationsJOURNAL OF ZOOLOGY, Issue 3 2004William E. Cooper Jr Abstract Costly anti-predatory defences are used in ecological time and maintained in evolutionary time by natural selection favouring individuals that survive through their use. Autotomy of expendable body parts is a striking example of a defence having multiple substantial costs, including loss of ability to use the same defence, loss of energy, and decreased growth, reproductive success and survival following autotomy, plus the energetic cost of replacing the lost body part in species capable of regenerating them. Our study shows that autotomy in the lacertid lizard Podarcis lilfordi reduces sprint speed, indicating decreased capacity to escape as well as the loss of energy. Autotomy carries substantial cost, and thus should be avoided except as a last resort. Ease of autotomy and post-autotomic movements were studied in three populations of lacertid lizards. Two were islet populations of P. lilfordi from Aire (lowest predation pressure) and Colom (intermediate predation pressure) off Minorca. The third was a mainland population of Podarcis hispanica, a closely related species from the mainland of the Iberian Peninsula where predation pressure is higher than on the islets. As predicted, a suite of autotomic traits increases the effectiveness of autotomy as a defence as predation pressure increases. With increasing predation pressure, the frequency of voluntary autotomy increases, latency to autotomy decreases, pressure on the tail needed to induce autotomy decreases, vigour of post-autotomic tail movements increases, and distance moved by the shed tail increases. Additional changes that might be related to predation pressure, but could have other causes, are the presence of tail coloration contrasting with body coloration except under the lowest predation pressure (Aire) and longer tails in the mainland species P. hispanica. Correspondence between predation pressure and the suite of autotomic traits suggests that autotomy is an important defence that responds to natural selection. Comparative data are needed to establish the generality of relationships suggested in our study of only three populations. [source] Litigation related to airway and respiratory complications of anaesthesia: an analysis of claims against the NHS in England 1995,2007ANAESTHESIA, Issue 6 2010T. M. Cook Summary Claims notified to the NHS Litigation Authority in England between 1995 and 2007 and filed under anaesthesia were analysed to explore patterns of injury and cost related to airway or respiratory events. Of 841 interpretable claims the final dataset contained 96 claims of dental damage, 67 airway-related claims and 24 respiratory claims. Claims of dental damage contributed a numerically important (11%), but financially modest (0.5%) proportion of claims. These claims predominantly described injury during tracheal intubation or extubation; a minority associated with electroconvulsive therapy led to substantial cost per claim. The total cost of (non-dental) airway claims was £4.9 million (84% closed, median cost £30 000) and that of respiratory claims was £3.3 million (81% closed, median £27 000). Airway and respiratory claims account for 12% of anaesthesia-related claims, 53% of deaths, 27% of cost and ten of the 50 most expensive claims in the dataset. Airway claims most frequently described events at induction of anaesthesia, involved airway management with a tracheal tube and typically led to hypoxia and patient death or brain injury. Airway trauma accounted for one third of airway claims and these included deaths from mediastinal injury at intubation. Pulmonary aspiration and tube misplacement, including oesophageal intubation, led to several claims. Among respiratory claims, ventilation problems, combined with hypoxia, were an important source of claims. Although limited clinical details hamper analysis, the data suggest that most airway and respiratory-related claims arise from sentinel events. The absence of clinical detail and denominators limit opportunities to learn from such events; much more could be learnt from a closed claim or sentinel event analysis scheme. [source] Epidemiology of transient ischemic attack and ischemic stroke in patients with underlying cardiovascular diseaseCLINICAL CARDIOLOGY, Issue S2 2004M.P.H., Philip B. Gorelick M.D. Abstract It is estimated that 15 to 30% of ischemic strokes are cardioembolic in origin, and that atrial fibrillation, valvular heart disease, coronary artery disease, congestive heart failure, and myocardial infarction are significant risk factors for stroke, which underscores the importance for cardiologists to understand this condition. The high incidence and substantial cost of stroke justify aggressive treatment of stroke risk factors, especially in the elderly, diabetic, and black populations, and in patients who have had an initial stroke. Antiplatelet therapy and administration of oral anticoagulants have both been shown to have a substantial impact on stroke in specified populations at risk. [source] ,I Can't Eat That, It's Purple': a Geography Field Course in Vanuatu and FijiGEOGRAPHICAL RESEARCH, Issue 1 2006JOHN CONNELL Abstract A month-long field course in the Pacific island states of Vanuatu and Fiji focused on development issues, involving lectures, seminars and much informal interaction. Students completed daily journals as a means of learning, a form of self-assessment of learning, a way of evaluating their participation in the course and their perception of its value. Journal themes reflected an evolution from unsettling rhetorical questions towards notions of discovery, autonomy, reflexivity and emerging cultural sensitivity. Students developed valuable social skills, and gained first-hand experience of various concepts of development and social justice. Grading the journals was difficult because of the extent of subjectivity and diverse personal experiences. The course, and the journals, emphasised the diverse values and roles of courses both on, and particularly in, developing countries, despite the substantial costs. [source] Individual variation in reproductive costs of reproduction: high-quality females always do betterJOURNAL OF ANIMAL ECOLOGY, Issue 1 2009Sandra Hamel Summary 1Although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. The apparent absence of reproductive costs may result from heterogeneity in individual quality. 2Using detailed longitudinal data from three contrasted ungulate populations (mountain goats, Oreamnos americanus; bighorn sheep, Ovis canadensis; and roe deer, Capreolus capreolus), we assessed how individual quality affects the probability of detecting a cost of current reproduction on future reproduction for females. We used a composite measure of individual quality based on variations in longevity (all species), success in the last breeding opportunity before death (goats and sheep), adult mass (all species), and social rank (goats only). 3In all species, high-quality females consistently had a higher probability of reproduction, irrespective of previous reproductive status. In mountain goats, we detected a cost of reproduction only after accounting for differences in individual quality. Only low-quality female goats were less likely to reproduce following years of breeding than of nonbreeding. Offspring survival was lower in bighorn ewes following years of successful breeding than after years when no lamb was produced, but only for low-quality females, suggesting that a cost of reproduction only occurred for low-quality females. 4Because costs of reproduction differ among females, studies of life-history evolution must account for heterogeneity in individual quality. [source] Monogamous pair bonds and mate switching in the Western Australian seahorse Hippocampus subelongatusJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2000C. Kvarnemo Apparently monogamous animals often prove, upon genetic inspection, to mate polygamously. Seahorse males provide care in a brood pouch. An earlier genetic study of the Western Australian seahorse demonstrated that males mate with only one female for each particular brood. Here we investigate whether males remain monogamous in sequential pregnancies during a breeding season. In a natural population we tagged males and sampled young from two successive broods of 14 males. Microsatellite analyses of parentage revealed that eight males re-mated with the same female, and six with a new female. Thus, in this first study to document long-term genetic monogamy in a seahorse, we show that switches of mates still occur. Polygynous males moved greater distances between broods, and tended to have longer interbrood intervals, than monogamous males, suggesting substantial costs associated with the breaking of pair bonds which may explain the high degree of social monogamy in this fish genus. [source] Ease and effectiveness of costly autotomy vary with predation intensity among lizard populationsJOURNAL OF ZOOLOGY, Issue 3 2004William E. Cooper Jr Abstract Costly anti-predatory defences are used in ecological time and maintained in evolutionary time by natural selection favouring individuals that survive through their use. Autotomy of expendable body parts is a striking example of a defence having multiple substantial costs, including loss of ability to use the same defence, loss of energy, and decreased growth, reproductive success and survival following autotomy, plus the energetic cost of replacing the lost body part in species capable of regenerating them. Our study shows that autotomy in the lacertid lizard Podarcis lilfordi reduces sprint speed, indicating decreased capacity to escape as well as the loss of energy. Autotomy carries substantial cost, and thus should be avoided except as a last resort. Ease of autotomy and post-autotomic movements were studied in three populations of lacertid lizards. Two were islet populations of P. lilfordi from Aire (lowest predation pressure) and Colom (intermediate predation pressure) off Minorca. The third was a mainland population of Podarcis hispanica, a closely related species from the mainland of the Iberian Peninsula where predation pressure is higher than on the islets. As predicted, a suite of autotomic traits increases the effectiveness of autotomy as a defence as predation pressure increases. With increasing predation pressure, the frequency of voluntary autotomy increases, latency to autotomy decreases, pressure on the tail needed to induce autotomy decreases, vigour of post-autotomic tail movements increases, and distance moved by the shed tail increases. Additional changes that might be related to predation pressure, but could have other causes, are the presence of tail coloration contrasting with body coloration except under the lowest predation pressure (Aire) and longer tails in the mainland species P. hispanica. Correspondence between predation pressure and the suite of autotomic traits suggests that autotomy is an important defence that responds to natural selection. Comparative data are needed to establish the generality of relationships suggested in our study of only three populations. [source] Description of an advanced practice nursing consultative model to reduce restrictive siderail use in nursing homes,,RESEARCH IN NURSING & HEALTH, Issue 2 2007Laura M. Wagner Abstract Researchers have demonstrated that the use of physical restraints in nursing homes can be reduced, particularly where advanced practice nurses (APNs) are utilized. We examined the link between APN practice, siderail reduction, and the costs of siderail alternatives in 273 residents in four Philadelphia nursing homes. The majority of participants were cognitively and physically impaired with multiple co-morbidities. APNs recommended a total of 1,275 siderail-alternative interventions aimed at reducing fall risk. The median cost of siderail alternatives to prevent falls per resident was $135. Residents with a fall history experienced a significantly higher cost of recommendation compared to non-fallers. Findings suggest that an APN consultation model can effectively be implemented through comprehensive, individualized assessment without incurring substantial costs to the nursing home. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30: 131,140, 2007 [source] |