Sample records for abundant dynamic cost-effective

  1. Dynamic regulation of partner abundance mediates response of reef coral symbioses to environmental change.

    PubMed

    Cunning, R; Vaughan, N; Gillette, P; Capo, T R; Matté, J L; Baker, A C

    2015-05-01

    Regulating partner abunclance may allow symmotic organisms to mediate interaction outcomes, facilitating adaptive responses to environmental change. To explore the capacity for-adaptive regulation in an ecologically important endosymbiosis, we studied the population dynamics of symbiotic algae in reef-building corals under different abiotic contexts. We found high natural variability in symbiont abundance in corals across reefs, but this variability converged to different symbiont-specific abundances when colonies were maintained under constant conditions. When conditions changed seasonally, symbiont abundance readjusted to new equilibria. We explain these patterns using an a priori model of symbiotic costs and benefits to the coral host, which shows that the observed changes in symbiont abundance are consistent with the maximization of interaction benefit under different environmental conditions. These results indicate that, while regulating symbiont abundance helps hosts sustain maximum benefit in a dynamic environment, spatiotemporal variation in abiotic factors creates a broad range of symbiont abundances (and interaction outcomes) among corals that may account for observed natural variability in performance (e.g., growth rate) and stress tolerance (e.g., bleaching susceptibility). This cost or benefit framework provides a new perspective on the dynamic regulation of reef coral symbioses and illustrates that the dependence of interaction outcomes on biotic and abiotic contexts may be important in understanding how diverse mutualisms respond to environmental change.

  2. Predicting the Dynamics of Protein Abundance

    PubMed Central

    Mehdi, Ahmed M.; Patrick, Ralph; Bailey, Timothy L.; Bodén, Mikael

    2014-01-01

    Protein synthesis is finely regulated across all organisms, from bacteria to humans, and its integrity underpins many important processes. Emerging evidence suggests that the dynamic range of protein abundance is greater than that observed at the transcript level. Technological breakthroughs now mean that sequencing-based measurement of mRNA levels is routine, but protocols for measuring protein abundance remain both complex and expensive. This paper introduces a Bayesian network that integrates transcriptomic and proteomic data to predict protein abundance and to model the effects of its determinants. We aim to use this model to follow a molecular response over time, from condition-specific data, in order to understand adaptation during processes such as the cell cycle. With microarray data now available for many conditions, the general utility of a protein abundance predictor is broad. Whereas most quantitative proteomics studies have focused on higher organisms, we developed a predictive model of protein abundance for both Saccharomyces cerevisiae and Schizosaccharomyces pombe to explore the latitude at the protein level. Our predictor primarily relies on mRNA level, mRNA–protein interaction, mRNA folding energy and half-life, and tRNA adaptation. The combination of key features, allowing for the low certainty and uneven coverage of experimental observations, gives comparatively minor but robust prediction accuracy. The model substantially improved the analysis of protein regulation during the cell cycle: predicted protein abundance identified twice as many cell-cycle-associated proteins as experimental mRNA levels. Predicted protein abundance was more dynamic than observed mRNA expression, agreeing with experimental protein abundance from a human cell line. We illustrate how the same model can be used to predict the folding energy of mRNA when protein abundance is available, lending credence to the emerging view that mRNA folding affects translation

  3. Predicting the dynamics of protein abundance.

    PubMed

    Mehdi, Ahmed M; Patrick, Ralph; Bailey, Timothy L; Bodén, Mikael

    2014-05-01

    Protein synthesis is finely regulated across all organisms, from bacteria to humans, and its integrity underpins many important processes. Emerging evidence suggests that the dynamic range of protein abundance is greater than that observed at the transcript level. Technological breakthroughs now mean that sequencing-based measurement of mRNA levels is routine, but protocols for measuring protein abundance remain both complex and expensive. This paper introduces a Bayesian network that integrates transcriptomic and proteomic data to predict protein abundance and to model the effects of its determinants. We aim to use this model to follow a molecular response over time, from condition-specific data, in order to understand adaptation during processes such as the cell cycle. With microarray data now available for many conditions, the general utility of a protein abundance predictor is broad. Whereas most quantitative proteomics studies have focused on higher organisms, we developed a predictive model of protein abundance for both Saccharomyces cerevisiae and Schizosaccharomyces pombe to explore the latitude at the protein level. Our predictor primarily relies on mRNA level, mRNA-protein interaction, mRNA folding energy and half-life, and tRNA adaptation. The combination of key features, allowing for the low certainty and uneven coverage of experimental observations, gives comparatively minor but robust prediction accuracy. The model substantially improved the analysis of protein regulation during the cell cycle: predicted protein abundance identified twice as many cell-cycle-associated proteins as experimental mRNA levels. Predicted protein abundance was more dynamic than observed mRNA expression, agreeing with experimental protein abundance from a human cell line. We illustrate how the same model can be used to predict the folding energy of mRNA when protein abundance is available, lending credence to the emerging view that mRNA folding affects translation efficiency

  4. Modelling community dynamics based on species-level abundance models from detection/nondetection data

    USGS Publications Warehouse

    Yamaura, Yuichi; Royle, J. Andrew; Kuboi, Kouji; Tada, Tsuneo; Ikeno, Susumu; Makino, Shun'ichi

    2011-01-01

    1. In large-scale field surveys, a binary recording of each species' detection or nondetection has been increasingly adopted for its simplicity and low cost. Because of the importance of abundance in many studies, it is desirable to obtain inferences about abundance at species-, functional group-, and community-levels from such binary data. 2. We developed a novel hierarchical multi-species abundance model based on species-level detection/nondetection data. The model accounts for the existence of undetected species, and variability in abundance and detectability among species. Species-level detection/nondetection is linked to species- level abundance via a detection model that accommodates the expectation that probability of detection (at least one individuals is detected) increases with local abundance of the species. We applied this model to a 9-year dataset composed of the detection/nondetection of forest birds, at a single post-fire site (from 7 to 15 years after fire) in a montane area of central Japan. The model allocated undetected species into one of the predefined functional groups by assuming a prior distribution on individual group membership. 3. The results suggest that 15–20 species were missed in each year, and that species richness of communities and functional groups did not change with post-fire forest succession. Overall abundance of birds and abundance of functional groups tended to increase over time, although only in the winter, while decreases in detectabilities were observed in several species. 4. Synthesis and applications. Understanding and prediction of large-scale biodiversity dynamics partly hinge on how we can use data effectively. Our hierarchical model for detection/nondetection data estimates abundance in space/time at species-, functional group-, and community-levels while accounting for undetected individuals and species. It also permits comparison of multiple communities by many types of abundance-based diversity and similarity

  5. Dynamic modeling of cost-effectiveness of rotavirus vaccination, Kazakhstan.

    PubMed

    Freiesleben de Blasio, Birgitte; Flem, Elmira; Latipov, Renat; Kuatbaeva, Ajnagul; Kristiansen, Ivar Sønbø

    2014-01-01

    The government of Kazakhstan, a middle-income country in Central Asia, is considering the introduction of rotavirus vaccination into its national immunization program. We performed a cost-effectiveness analysis of rotavirus vaccination spanning 20 years by using a synthesis of dynamic transmission models accounting for herd protection. We found that a vaccination program with 90% coverage would prevent ≈880 rotavirus deaths and save an average of 54,784 life-years for children <5 years of age. Indirect protection accounted for 40% and 60% reduction in severe and mild rotavirus gastroenteritis, respectively. Cost per life year gained was US $18,044 from a societal perspective and US $23,892 from a health care perspective. Comparing the 2 key parameters of cost-effectiveness, mortality rates and vaccine cost at costs would be entirely offset. To further evaluate efficacy of a vaccine program, benefits of indirect protection conferred by vaccination warrant further study.

  6. Cost-Effective Large-Scale Occupancy–Abundance Monitoring of Invasive Brushtail Possums (Trichosurus Vulpecula) on New Zealand’s Public Conservation Land

    PubMed Central

    Gormley, Andrew M.; Forsyth, David M.; Wright, Elaine F.; Lyall, John; Elliott, Mike; Martini, Mark; Kappers, Benno; Perry, Mike; McKay, Meredith

    2015-01-01

    There is interest in large-scale and unbiased monitoring of biodiversity status and trend, but there are few published examples of such monitoring being implemented. The New Zealand Department of Conservation is implementing a monitoring program that involves sampling selected biota at the vertices of an 8-km grid superimposed over the 8.6 million hectares of public conservation land that it manages. The introduced brushtail possum (Trichosurus Vulpecula) is a major threat to some biota and is one taxon that they wish to monitor and report on. A pilot study revealed that the traditional method of monitoring possums using leg-hold traps set for two nights, termed the Trap Catch Index, was a constraint on the cost and logistical feasibility of the monitoring program. A phased implementation of the monitoring program was therefore conducted to collect data for evaluating the trade-off between possum occupancy–abundance estimates and the costs of sampling for one night rather than two nights. Reducing trapping effort from two nights to one night along four trap-lines reduced the estimated costs of monitoring by 5.8% due to savings in labour, food and allowances; it had a negligible effect on estimated national possum occupancy but resulted in slightly higher and less precise estimates of relative possum abundance. Monitoring possums for one night rather than two nights would provide an annual saving of NZ$72,400, with 271 fewer field days required for sampling. Possums occupied 60% (95% credible interval; 53–68) of sampling locations on New Zealand’s public conservation land, with a mean relative abundance (Trap Catch Index) of 2.7% (2.0–3.5). Possum occupancy and abundance were higher in forest than in non-forest habitats. Our case study illustrates the need to evaluate relationships between sampling design, cost, and occupancy–abundance estimates when designing and implementing large-scale occupancy–abundance monitoring programs. PMID:26029890

  7. An integrated data model to estimate spatiotemporal occupancy, abundance, and colonization dynamics

    USGS Publications Warehouse

    Williams, Perry J.; Hooten, Mevin B.; Womble, Jamie N.; Esslinger, George G.; Bower, Michael R.; Hefley, Trevor J.

    2017-01-01

    Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when modeling spatiotemporal ecological data including multiple levels of detection probability, multiple data sources, and computational limitations that occur when making fine-scale inference over a large spatiotemporal domain. We apply the model to estimate the colonization dynamics of sea otters (Enhydra lutris) in Glacier Bay, in southeastern Alaska.

  8. An integrated data model to estimate spatiotemporal occupancy, abundance, and colonization dynamics.

    PubMed

    Williams, Perry J; Hooten, Mevin B; Womble, Jamie N; Esslinger, George G; Bower, Michael R; Hefley, Trevor J

    2017-02-01

    Ecological invasions and colonizations occur dynamically through space and time. Estimating the distribution and abundance of colonizing species is critical for efficient management or conservation. We describe a statistical framework for simultaneously estimating spatiotemporal occupancy and abundance dynamics of a colonizing species. Our method accounts for several issues that are common when modeling spatiotemporal ecological data including multiple levels of detection probability, multiple data sources, and computational limitations that occur when making fine-scale inference over a large spatiotemporal domain. We apply the model to estimate the colonization dynamics of sea otters (Enhydra lutris) in Glacier Bay, in southeastern Alaska. © 2016 by the Ecological Society of America.

  9. Cost-effectiveness of dengue vaccination in Yucatán, Mexico using a dynamic dengue transmission model

    PubMed Central

    Shim, Eunha

    2017-01-01

    Background The incidence of dengue fever (DF) is steadily increasing in Mexico, burdening health systems with consequent morbidities and mortalities. On December 9th, 2015, Mexico became the first country for which the dengue vaccine was approved for use. In anticipation of a vaccine rollout, analysis of the cost-effectiveness of the dengue vaccination program that quantifies the dynamics of disease transmission is essential. Methods We developed a dynamic transmission model of dengue in Yucatán, Mexico and its proposed vaccination program to incorporate herd immunity into our analysis of cost-effectiveness analysis. Our model also incorporates important characteristics of dengue epidemiology, such as clinical cross-immunity and susceptibility enhancement upon secondary infection. Using our model, we evaluated the cost-effectiveness and economic impact of an imperfect dengue vaccine in Yucatán, Mexico. Conclusions Our study indicates that a dengue vaccination program would prevent 90% of cases of symptomatic DF incidence as well as 90% of dengue hemorrhagic fever (DHF) incidence and dengue-related deaths annually. We conclude that a dengue vaccine program in Yucatán, Mexico would be very cost-effective as long as the vaccination cost per individual is less than $140 and $214 from health care and societal perspectives, respectively. Furthermore, at an exemplary vaccination cost of $250 USD per individual on average, dengue vaccination is likely to be cost-effective 43% and 88% of the time from health care and societal perspectives, respectively. PMID:28380060

  10. Cost-effectiveness of dengue vaccination in Yucatán, Mexico using a dynamic dengue transmission model.

    PubMed

    Shim, Eunha

    2017-01-01

    The incidence of dengue fever (DF) is steadily increasing in Mexico, burdening health systems with consequent morbidities and mortalities. On December 9th, 2015, Mexico became the first country for which the dengue vaccine was approved for use. In anticipation of a vaccine rollout, analysis of the cost-effectiveness of the dengue vaccination program that quantifies the dynamics of disease transmission is essential. We developed a dynamic transmission model of dengue in Yucatán, Mexico and its proposed vaccination program to incorporate herd immunity into our analysis of cost-effectiveness analysis. Our model also incorporates important characteristics of dengue epidemiology, such as clinical cross-immunity and susceptibility enhancement upon secondary infection. Using our model, we evaluated the cost-effectiveness and economic impact of an imperfect dengue vaccine in Yucatán, Mexico. Our study indicates that a dengue vaccination program would prevent 90% of cases of symptomatic DF incidence as well as 90% of dengue hemorrhagic fever (DHF) incidence and dengue-related deaths annually. We conclude that a dengue vaccine program in Yucatán, Mexico would be very cost-effective as long as the vaccination cost per individual is less than $140 and $214 from health care and societal perspectives, respectively. Furthermore, at an exemplary vaccination cost of $250 USD per individual on average, dengue vaccination is likely to be cost-effective 43% and 88% of the time from health care and societal perspectives, respectively.

  11. A stable dynamic cohort analysis of installing cost-effective rollover protective structures (CROPS).

    PubMed

    Owusu-Edusei, K; Biddle, E A

    2007-04-01

    Cost-effective rollover protective structures (CROPS) are less costly model-specific rollover protective structure (ROPS) retrofits that are being developed and evaluated with the hope of increasing adoption and eventually preventing or mitigating injuries due to tractor overturns. A dynamic cohort of the estimated retrofittable non-ROPS tractors (accounting for attrition due to aging) was tracked over a 20-year period to determine the expected costs, as well as the expected number of fatal and non-fatal injuries resulting from tractor overturns. Two alternatives were tracked: No-ROPS and Install-CROPS. For a starting cohort size of 1,065,164 (an estimate for the year 2004), the Install-CROPS option prevented an estimated total of 878 (192 fatal and 686 non-fatal) injuries over the 20-year period. Expected costs were $513 million (cost of installing CROPS on all the non-ROPS tractors plus cost of the associated injuries) and $284 million (cost of injuries resulting from the No-ROPS option) over the same time period. Thus, the net cost per injury prevented was $260,820. When the cost of intervention ($1000 for purchasing, shipping, and installation of existing ROPS retrofit) was used in the analysis, the cost-effectiveness ratio was $927,000 per injury prevented over the 20-year period. Thus, installing CROPS instead of existing ROPS retrofits improved the cost-effectiveness ratio substantially, with a 72% reduction in the net cost per injury prevented.

  12. Dynamic N -occupancy models: estimating demographic rates and local abundance from detection-nondetection data

    Treesearch

    Sam Rossman; Charles B. Yackulic; Sarah P. Saunders; Janice Reid; Ray Davis; Elise F. Zipkin

    2016-01-01

    Occupancy modeling is a widely used analytical technique for assessing species distributions and range dynamics. However, occupancy analyses frequently ignore variation in abundance of occupied sites, even though site abundances affect many of the parameters being estimated (e.g., extinction, colonization, detection probability). We introduce a new model (“dynamic

  13. Pan-Antarctic analysis aggregating spatial estimates of Adélie penguin abundance reveals robust dynamics despite stochastic noise.

    PubMed

    Che-Castaldo, Christian; Jenouvrier, Stephanie; Youngflesh, Casey; Shoemaker, Kevin T; Humphries, Grant; McDowall, Philip; Landrum, Laura; Holland, Marika M; Li, Yun; Ji, Rubao; Lynch, Heather J

    2017-10-10

    Colonially-breeding seabirds have long served as indicator species for the health of the oceans on which they depend. Abundance and breeding data are repeatedly collected at fixed study sites in the hopes that changes in abundance and productivity may be useful for adaptive management of marine resources, but their suitability for this purpose is often unknown. To address this, we fit a Bayesian population dynamics model that includes process and observation error to all known Adélie penguin abundance data (1982-2015) in the Antarctic, covering >95% of their population globally. We find that process error exceeds observation error in this system, and that continent-wide "year effects" strongly influence population growth rates. Our findings have important implications for the use of Adélie penguins in Southern Ocean feedback management, and suggest that aggregating abundance across space provides the fastest reliable signal of true population change for species whose dynamics are driven by stochastic processes.Adélie penguins are a key Antarctic indicator species, but data patchiness has challenged efforts to link population dynamics to key drivers. Che-Castaldo et al. resolve this issue using a pan-Antarctic Bayesian model to infer missing data, and show that spatial aggregation leads to more robust inference regarding dynamics.

  14. [Effects of macro-jellyfish abundance dynamics on fishery resource structure in the Yangtze River estuary and its adjacent waters].

    PubMed

    Shan, Xiu-Juan; Zhuang, Zhi-Meng; Jin, Xian-Shi; Dai, Fang-Qun

    2011-12-01

    Based on the bottom trawl survey data in May 2007 and May and June 2008, this paper analyzed the effects of the abundance dynamics of macro-jellyfish on the species composition, distribution, and abundance of fishery resource in the Yangtze River estuary and its adjacent waters. From May 2007 to June 2008, the average catch per haul and the top catch per haul of macro-jellyfish increased, up to 222.2 kg x h(-1) and 1800 kg x h(-1) in June 2008, respectively. The macro-jellyfish were mainly distributed in the areas around 50 m isobath, and not beyond 100 m isobath where was the joint front of the coastal waters of East China Sea, Yangtze River runoff, and Taiwan Warm Current. The main distribution area of macro-jellyfish in June migrated northward, as compared with that in May, and the highest catches of macro-jellyfish in May 2007 and May 2008 were found in the same sampling station (122.5 degrees E, 28.5 degrees N). In the sampling stations with higher abundance of macro-jellyfish, the fishery abundance was low, and the fishery species also changed greatly, mainly composed by small-sized species (Trachurus japonicus, Harpadon nehereus, and Acropoma japonicum) and pelagic species (Psenopsis anomala, Octopus variabilis) and Trichiurus japonicus, and P. anomala accounted for 23.7% of the total catch in June 2008. Larimichthys polyactis also occupied higher proportion of the total catch in sampling stations with higher macro-jellyfish abundance, but the demersal species Lophius litulon was not found, and a few crustaceans were collected. This study showed that macro-jellyfish had definite negative effects on the fishery community structure and abundance in the Yangtze River estuary fishery ecosystem, and further, changed the energy flow patterns of the ecosystem through cascading trophic interactions. Therefore, macro-jellyfish was strongly suggested to be an independent ecological group when the corresponding fishery management measures were considered.

  15. Occupancy and abundance of wintering birds in a dynamic agricultural landscape

    USGS Publications Warehouse

    Miller, Mark W.; Pearlstine, Elise V.; Dorazio, Robert M.; Mazzotti, Frank J.

    2011-01-01

    Assessing wildlife management action requires monitoring populations, and abundance often is the parameter monitored. Recent methodological advances have enabled estimation of mean abundance within a habitat using presence–absence or count data obtained via repeated visits to a sample of sites. These methods assume populations are closed and intuitively assume habitats within sites change little during a field season. However, many habitats are highly variable over short periods. We developed a variation of existing occupancy and abundance models that allows for extreme spatio-temporal differences in habitat, and resulting changes in wildlife abundance, among sites and among visits to a site within a field season. We conducted our study in sugarcane habitat within the Everglades Agricultural Area southeast of Lake Okeechobee in south Florida. We counted wintering birds, primarily passerines, within 245 sites usually 5 times at each site during December 2006–March 2007. We estimated occupancy and mean abundance of birds in 6 vegetation states during the sugarcane harvest and allowed these parameters to vary temporally or spatially within a vegetation state. Occupancy and mean abundance of the common yellowthroat (Geothlypis trichas) was affected by structure of sugarcane and uncultivated edge vegetation (occupancy=1.00 [95%CĪ=0.96–1.00] and mean abundance=7.9 [95%CĪ=3.2–19.5] in tall sugarcane with tall edge vegetation versus 0.20 [95%CĪ=0.04–0.71] and 0.22 [95%CĪ=0.04–1.2], respectively, in short sugarcane with short edge vegetation in one half of the study area). Occupancy and mean abundance of palm warblers (Dendroica palmarum) were constant (occupancy=1.00, 95%CĪ=0.69–1.00; mean abundance=18, 95%CĪ=1–270). Our model may enable wildlife managers to assess rigorously effects of future edge habitat management on avian distribution and abundance within agricultural landscapes during winter or the breeding season. The model may also help

  16. Occupancy and abundance of wintering birds in a dynamic agricultural landscape

    USGS Publications Warehouse

    Miller, M.W.; Pearlstine, E.V.; Dorazio, R.M.; Mazzotti, F.J.

    2011-01-01

    Assessing wildlife management action requires monitoring populations, and abundance often is the parameter monitored. Recent methodological advances have enabled estimation of mean abundance within a habitat using presence-absence or count data obtained via repeated visits to a sample of sites. These methods assume populations are closed and intuitively assume habitats within sites change little during a field season. However, many habitats are highly variable over short periods. We developed a variation of existing occupancy and abundance models that allows for extreme spatio-temporal differences in habitat, and resulting changes in wildlife abundance, among sites and among visits to a site within a field season. We conducted our study in sugarcane habitat within the Everglades Agricultural Area southeast of Lake Okeechobee in south Florida. We counted wintering birds, primarily passerines, within 245 sites usually 5 times at each site during December 2006-March 2007. We estimated occupancy and mean abundance of birds in 6 vegetation states during the sugarcane harvest and allowed these parameters to vary temporally or spatially within a vegetation state. Occupancy and mean abundance of the common yellowthroat (Geothlypis trichas) was affected by structure of sugarcane and uncultivated edge vegetation (occupancy = 1.00 [95%C?? = 0.96-1.00] and mean abundance = 7.9 [95%C?? = 3.2-19.5] in tall sugarcane with tall edge vegetation versus 0.20 [95%C?? = 0.04-0.71] and 0.22 [95%C?? = 0.04-1.2], respectively, in short sugarcane with short edge vegetation in one half of the study area). Occupancy and mean abundance of palm warblers (Dendroica palmarum) were constant (occupancy = 1.00, 95%C?? = 0.69-1.00; mean abundance = 18, 95%C?? = 1-270). Our model may enable wildlife managers to assess rigorously effects of future edge habitat management on avian distribution and abundance within agricultural landscapes during winter or the breeding season. The model may also help

  17. Fish and Phytoplankton Exhibit Contrasting Temporal Species Abundance Patterns in a Dynamic North Temperate Lake

    PubMed Central

    Hansen, Gretchen J. A.; Carey, Cayelan C.

    2015-01-01

    Temporal patterns of species abundance, although less well-studied than spatial patterns, provide valuable insight to the processes governing community assembly. We compared temporal abundance distributions of two communities, phytoplankton and fish, in a north temperate lake. We used both 17 years of observed relative abundance data as well as resampled data from Monte Carlo simulations to account for the possible effects of non-detection of rare species. Similar to what has been found in other communities, phytoplankton and fish species that appeared more frequently were generally more abundant than rare species. However, neither community exhibited two distinct groups of “core” (common occurrence and high abundance) and “occasional” (rare occurrence and low abundance) species. Both observed and resampled data show that the phytoplankton community was dominated by occasional species appearing in only one year that exhibited large variation in their abundances, while the fish community was dominated by core species occurring in all 17 years at high abundances. We hypothesize that the life-history traits that enable phytoplankton to persist in highly dynamic environments may result in communities dominated by occasional species capable of reaching high abundances when conditions allow. Conversely, longer turnover times and broad environmental tolerances of fish may result in communities dominated by core species structured primarily by competitive interactions. PMID:25651399

  18. Detecting declines in the abundance of a bull trout (Salvelinus confluentus) population: Understanding the accuracy, precision, and costs of our efforts

    USGS Publications Warehouse

    Al-Chokhachy, R.; Budy, P.; Conner, M.

    2009-01-01

    Using empirical field data for bull trout (Salvelinus confluentus), we evaluated the trade-off between power and sampling effort-cost using Monte Carlo simulations of commonly collected mark-recapture-resight and count data, and we estimated the power to detect changes in abundance across different time intervals. We also evaluated the effects of monitoring different components of a population and stratification methods on the precision of each method. Our results illustrate substantial variability in the relative precision, cost, and information gained from each approach. While grouping estimates by age or stage class substantially increased the precision of estimates, spatial stratification of sampling units resulted in limited increases in precision. Although mark-resight methods allowed for estimates of abundance versus indices of abundance, our results suggest snorkel surveys may be a more affordable monitoring approach across large spatial scales. Detecting a 25% decline in abundance after 5 years was not possible, regardless of technique (power = 0.80), without high sampling effort (48% of study site). Detecting a 25% decline was possible after 15 years, but still required high sampling efforts. Our results suggest detecting moderate changes in abundance of freshwater salmonids requires considerable resource and temporal commitments and highlight the difficulties of using abundance measures for monitoring bull trout populations.

  19. Cost-effectiveness analysis and innovation.

    PubMed

    Jena, Anupam B; Philipson, Tomas J

    2008-09-01

    While cost-effectiveness (CE) analysis has provided a guide to allocating often scarce resources spent on medical technologies, less emphasis has been placed on the effect of such criteria on the behavior of innovators who make health care technologies available in the first place. A better understanding of the link between innovation and cost-effectiveness analysis is particularly important given the large role of technological change in the growth in health care spending and the growing interest of explicit use of CE thresholds in leading technology adoption in several Westernized countries. We analyze CE analysis in a standard market context, and stress that a technology's cost-effectiveness is closely related to the consumer surplus it generates. Improved CE therefore often clashes with interventions to stimulate producer surplus, such as patents. We derive the inconsistency between technology adoption based on CE analysis and economic efficiency. Indeed, static efficiency, dynamic efficiency, and improved patient health may all be induced by the cost-effectiveness of the technology being at its worst level. As producer appropriation of the social surplus of an innovation is central to the dynamic efficiency that should guide CE adoption criteria, we exemplify how appropriation can be inferred from existing CE estimates. For an illustrative sample of technologies considered, we find that the median technology has an appropriation of about 15%. To the extent that such incentives are deemed either too low or too high compared to dynamically efficient levels, CE thresholds may be appropriately raised or lowered to improve dynamic efficiency.

  20. Population dynamics and mutualism: Functional responses of benefits and costs

    USGS Publications Warehouse

    Holland, J. Nathaniel; DeAngelis, Donald L.; Bronstein, Judith L.

    2002-01-01

    We develop an approach for studying population dynamics resulting from mutualism by employing functional responses based on density‐dependent benefits and costs. These functional responses express how the population growth rate of a mutualist is modified by the density of its partner. We present several possible dependencies of gross benefits and costs, and hence net effects, to a mutualist as functions of the density of its partner. Net effects to mutualists are likely a monotonically saturating or unimodal function of the density of their partner. We show that fundamental differences in the growth, limitation, and dynamics of a population can occur when net effects to that population change linearly, unimodally, or in a saturating fashion. We use the mutualism between senita cactus and its pollinating seed‐eating moth as an example to show the influence of different benefit and cost functional responses on population dynamics and stability of mutualisms. We investigated two mechanisms that may alter this mutualism's functional responses: distribution of eggs among flowers and fruit abortion. Differences in how benefits and costs vary with density can alter the stability of this mutualism. In particular, fruit abortion may allow for a stable equilibrium where none could otherwise exist.

  1. Modeling abundance effects in distance sampling

    USGS Publications Warehouse

    Royle, J. Andrew; Dawson, D.K.; Bates, S.

    2004-01-01

    Distance-sampling methods are commonly used in studies of animal populations to estimate population density. A common objective of such studies is to evaluate the relationship between abundance or density and covariates that describe animal habitat or other environmental influences. However, little attention has been focused on methods of modeling abundance covariate effects in conventional distance-sampling models. In this paper we propose a distance-sampling model that accommodates covariate effects on abundance. The model is based on specification of the distance-sampling likelihood at the level of the sample unit in terms of local abundance (for each sampling unit). This model is augmented with a Poisson regression model for local abundance that is parameterized in terms of available covariates. Maximum-likelihood estimation of detection and density parameters is based on the integrated likelihood, wherein local abundance is removed from the likelihood by integration. We provide an example using avian point-transect data of Ovenbirds (Seiurus aurocapillus) collected using a distance-sampling protocol and two measures of habitat structure (understory cover and basal area of overstory trees). The model yields a sensible description (positive effect of understory cover, negative effect on basal area) of the relationship between habitat and Ovenbird density that can be used to evaluate the effects of habitat management on Ovenbird populations.

  2. Cost-effectiveness of vaccination with a quadrivalent HPV vaccine in Germany using a dynamic transmission model

    PubMed Central

    2012-01-01

    Introduction Persistent infections with human papillomavirus (HPV) are a necessary cause of cervical cancer and are responsible for important morbidity in men and women. Since 2007, HPV vaccination has been recommended and funded for all girls aged 12 to 17 in Germany. A previously published cost-effectiveness analysis, using a static model, showed that a quadrivalent HPV vaccination programme for 12-year-old girls in Germany would be cost effective. Here we present the results from a dynamic transmission model that can be used to evaluate the impact and cost-effectiveness of different vaccination schemas. Methods We adapted a HPV dynamic transmission model, which has been used in other countries, to the German context. The model was used to compare a cervical cancer screening only strategy with a strategy of combining vaccination of females aged 12–17 years old and cervical cancer screening, based on the current recommendations in Germany. In addition, the impact of increasing vaccination coverage in this cohort of females aged 12–17 years old was evaluated in sensitivity analysis. Results The results from this analysis show that the current quadrivalent HPV vaccination programme of females ages 12 to 17 in Germany is cost-effective with an ICER of 5,525€/QALY (quality adjusted life year). The incremental cost-effectiveness ratio (ICER) increased to 10,293€/QALY when the vaccine effects on HPV6/11 diseases were excluded. At steady state, the model predicted that vaccinating girls aged 12 to 17 could reduce the number of HPV 6/11/16/18-related cervical cancers by 65% and genital warts among women and men by 70% and 48%, respectively. The impact on HPV-related disease incidence and costs avoided would occur relatively soon after initiating the vaccine programme, with much of the early impact being due to the prevention of HPV6/11-related genital warts. Conclusions These results show that the current quadrivalent HPV vaccination and cervical cancer screening

  3. Cost-effectiveness of vaccination with a quadrivalent HPV vaccine in Germany using a dynamic transmission model.

    PubMed

    Schobert, Deniz; Remy, Vanessa; Schoeffski, Oliver

    2012-09-25

    Persistent infections with human papillomavirus (HPV) are a necessary cause of cervical cancer and are responsible for important morbidity in men and women. Since 2007, HPV vaccination has been recommended and funded for all girls aged 12 to 17 in Germany. A previously published cost-effectiveness analysis, using a static model, showed that a quadrivalent HPV vaccination programme for 12-year-old girls in Germany would be cost effective. Here we present the results from a dynamic transmission model that can be used to evaluate the impact and cost-effectiveness of different vaccination schemas. We adapted a HPV dynamic transmission model, which has been used in other countries, to the German context. The model was used to compare a cervical cancer screening only strategy with a strategy of combining vaccination of females aged 12-17 years old and cervical cancer screening, based on the current recommendations in Germany. In addition, the impact of increasing vaccination coverage in this cohort of females aged 12-17 years old was evaluated in sensitivity analysis. The results from this analysis show that the current quadrivalent HPV vaccination programme of females ages 12 to 17 in Germany is cost-effective with an ICER of 5,525€/QALY (quality adjusted life year). The incremental cost-effectiveness ratio (ICER) increased to 10,293€/QALY when the vaccine effects on HPV6/11 diseases were excluded. At steady state, the model predicted that vaccinating girls aged 12 to 17 could reduce the number of HPV 6/11/16/18-related cervical cancers by 65% and genital warts among women and men by 70% and 48%, respectively. The impact on HPV-related disease incidence and costs avoided would occur relatively soon after initiating the vaccine programme, with much of the early impact being due to the prevention of HPV6/11-related genital warts. These results show that the current quadrivalent HPV vaccination and cervical cancer screening programmes in Germany will substantially

  4. Ab initio molecular dynamics with nuclear quantum effects at classical cost: Ring polymer contraction for density functional theory.

    PubMed

    Marsalek, Ondrej; Markland, Thomas E

    2016-02-07

    Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding as a reference system, we show that our ring polymer contraction scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive protonated and deprotonated water dimer systems. We find that the vast majority of the nuclear quantum effects are accurately captured using contraction to just the ring polymer centroid, which requires the same number of density functional theory calculations as a classical simulation. Combined with a multiple time step scheme using the same reference system, which allows the time step to be increased, this approach is as fast as a typical classical ab initio molecular dynamics simulation and 35× faster than a full path integral calculation, while still exactly including the quantum sampling of nuclei. This development thus offers a route to routinely include nuclear quantum effects in ab initio molecular dynamics simulations at negligible computational cost.

  5. Increased natural mortality at low abundance can generate an Allee effect in a marine fish.

    PubMed

    Kuparinen, Anna; Hutchings, Jeffrey A

    2014-10-01

    Negative density-dependent regulation of population dynamics promotes population growth at low abundance and is therefore vital for recovery following depletion. Inversely, any process that reduces the compensatory density-dependence of population growth can negatively affect recovery. Here, we show that increased adult mortality at low abundance can reverse compensatory population dynamics into its opposite-a demographic Allee effect. Northwest Atlantic cod (Gadus morhua) stocks collapsed dramatically in the early 1990s and have since shown little sign of recovery. Many experienced dramatic increases in natural mortality, ostensibly attributable in some populations to increased predation by seals. Our findings show that increased natural mortality of a magnitude observed for overfished cod stocks has been more than sufficient to fundamentally alter the dynamics of density-dependent population regulation. The demographic Allee effect generated by these changes can slow down or even impede the recovery of depleted populations even in the absence of fishing.

  6. Using spatiotemporal statistical models to estimate animal abundance and infer ecological dynamics from survey counts

    USGS Publications Warehouse

    Conn, Paul B.; Johnson, Devin S.; Ver Hoef, Jay M.; Hooten, Mevin B.; London, Joshua M.; Boveng, Peter L.

    2015-01-01

    Ecologists often fit models to survey data to estimate and explain variation in animal abundance. Such models typically require that animal density remains constant across the landscape where sampling is being conducted, a potentially problematic assumption for animals inhabiting dynamic landscapes or otherwise exhibiting considerable spatiotemporal variation in density. We review several concepts from the burgeoning literature on spatiotemporal statistical models, including the nature of the temporal structure (i.e., descriptive or dynamical) and strategies for dimension reduction to promote computational tractability. We also review several features as they specifically relate to abundance estimation, including boundary conditions, population closure, choice of link function, and extrapolation of predicted relationships to unsampled areas. We then compare a suite of novel and existing spatiotemporal hierarchical models for animal count data that permit animal density to vary over space and time, including formulations motivated by resource selection and allowing for closed populations. We gauge the relative performance (bias, precision, computational demands) of alternative spatiotemporal models when confronted with simulated and real data sets from dynamic animal populations. For the latter, we analyze spotted seal (Phoca largha) counts from an aerial survey of the Bering Sea where the quantity and quality of suitable habitat (sea ice) changed dramatically while surveys were being conducted. Simulation analyses suggested that multiple types of spatiotemporal models provide reasonable inference (low positive bias, high precision) about animal abundance, but have potential for overestimating precision. Analysis of spotted seal data indicated that several model formulations, including those based on a log-Gaussian Cox process, had a tendency to overestimate abundance. By contrast, a model that included a population closure assumption and a scale prior on total

  7. Effects of Cluster Environment on Chemical Abundances in Virgo Cluster Spirals

    NASA Astrophysics Data System (ADS)

    Kennicutt, R. C.; Skillman, E. D.; Shields, G. A.; Zaritsky, D.

    1995-12-01

    We have obtained new chemical abundance measurements of HII regions in Virgo cluster spiral galaxies, in order to test whether the cluster environment has significantly influenced the gas-phase abundances and chemical evolution of spiral disks. The sample of 9 Virgo spirals covers a narrow range of morphological type (Sbc - Sc) but shows broad ranges in HI deficiencies and radii in the cluster. This allows us to compare the Virgo sample as a whole to field spirals, using a large sample from Zaritsky, Kennicutt, & Huchra, and to test for systematic trends with HI content and location within the cluster. The Virgo spirals show a wide dispersion in mean disk abundances and abundance gradients. Strongly HI deficient spirals closest to the cluster core show anomalously high oxygen abundances (by 0.3 to 0.5 dex), while outlying spirals with normal HI content show abundances similar to those of field spirals. The most HI depleted spirals also show weaker abundance gradients on average, but the formal significance of this trend is marginal. We find a strong correlation between mean abundance and HI/optical diameter ratio that is quite distinct from the behavior seen in field galaxies. This suggests that dynamical processes associated with the cluster environment are more important than cluster membership in determining the evolution of chemical abundances and stellar populations in spiral galaxies. Simple chemical evolution models are calculated to predict the magnitude of the abundance enhancement expected if ram-pressure stripping or curtailment of infall is responsible for the gas deficiencies. The increased abundances of the spirals in the cluster core may have significant effects on their use as cosmological standard candles.

  8. Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England forest

    PubMed Central

    Ellison, Aaron M.; Jackson, Scott

    2015-01-01

    Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m2 and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys, but underestimated true density by 50%. In contrast, the abundance index based on cover-board surveys overestimated true density by a factor of 8 and the association between the cover-board index and the density estimates was not statistically significant. We conclude that when calibrated and used appropriately, some abundance indices may provide cost-effective and reliable measures of P. cinereus abundance that could

  9. Ab initio molecular dynamics with nuclear quantum effects at classical cost: Ring polymer contraction for density functional theory

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Marsalek, Ondrej; Markland, Thomas E., E-mail: tmarkland@stanford.edu

    Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding asmore » a reference system, we show that our ring polymer contraction scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive protonated and deprotonated water dimer systems. We find that the vast majority of the nuclear quantum effects are accurately captured using contraction to just the ring polymer centroid, which requires the same number of density functional theory calculations as a classical simulation. Combined with a multiple time step scheme using the same reference system, which allows the time step to be increased, this approach is as fast as a typical classical ab initio molecular dynamics simulation and 35× faster than a full path integral calculation, while still exactly including the quantum sampling of nuclei. This development thus offers a route to routinely include nuclear quantum effects in ab initio molecular dynamics simulations at negligible computational cost.« less

  10. Lead sulphide: Low cost, abundant thermoelectrics

    NASA Astrophysics Data System (ADS)

    Ahmad, Sajid; Singh, Ajay; Bhattacharya, Shovit; Basu, Ranita; Bhatt, Ranu; Bohra, Anil; Muthe, K. P.; Gadkari, S. C.

    2018-04-01

    Lead and sulphur are the most abundant and low cost materials on the earth's crust, lead chalcogenide (S, Se and Te) materials have got best applications in thermoelectric power generations. Among the chalcogenides, selenium and tellurium are costlier and are more toxic material than sulphur. [1][2] Decreasing the thermal conductivity has been proven to be the easiest approach to improve the thermoelectric performance of a material. In the present work, the lead sulphide (PbS) and SrxPb(1-x)S composite materials were synthesized and investigated. Addition of 0.4 and 0.8 moles of Sr atoms into the PbS lattice has appreciably reduced the thermal conductivity from 2.2 W/mK to 0.43 W/mK for Sr0.4Pb0.6S composition. Temperature (T) dependence of thermoelectric (TE) properties PbS and and SrxPb(1-x)S nanocomposite material has been studied with in the temperature range of 300 K to 700 K. It is observed that there is reduction in the thermal conductivity of PbS alloy on addition of Sr that is mainly attributed to the scattering centres of Sr in the PbS matrix also the presence of the Sr also plays a role in the refinement of the PbS matrix.

  11. Restoration ecology: two-sex dynamics and cost minimization.

    PubMed

    Molnár, Ferenc; Caragine, Christina; Caraco, Thomas; Korniss, Gyorgy

    2013-01-01

    We model a spatially detailed, two-sex population dynamics, to study the cost of ecological restoration. We assume that cost is proportional to the number of individuals introduced into a large habitat. We treat dispersal as homogeneous diffusion in a one-dimensional reaction-diffusion system. The local population dynamics depends on sex ratio at birth, and allows mortality rates to differ between sexes. Furthermore, local density dependence induces a strong Allee effect, implying that the initial population must be sufficiently large to avert rapid extinction. We address three different initial spatial distributions for the introduced individuals; for each we minimize the associated cost, constrained by the requirement that the species must be restored throughout the habitat. First, we consider spatially inhomogeneous, unstable stationary solutions of the model's equations as plausible candidates for small restoration cost. Second, we use numerical simulations to find the smallest rectangular cluster, enclosing a spatially homogeneous population density, that minimizes the cost of assured restoration. Finally, by employing simulated annealing, we minimize restoration cost among all possible initial spatial distributions of females and males. For biased sex ratios, or for a significant between-sex difference in mortality, we find that sex-specific spatial distributions minimize the cost. But as long as the sex ratio maximizes the local equilibrium density for given mortality rates, a common homogeneous distribution for both sexes that spans a critical distance yields a similarly low cost.

  12. Restoration Ecology: Two-Sex Dynamics and Cost Minimization

    PubMed Central

    Molnár, Ferenc; Caragine, Christina; Caraco, Thomas; Korniss, Gyorgy

    2013-01-01

    We model a spatially detailed, two-sex population dynamics, to study the cost of ecological restoration. We assume that cost is proportional to the number of individuals introduced into a large habitat. We treat dispersal as homogeneous diffusion in a one-dimensional reaction-diffusion system. The local population dynamics depends on sex ratio at birth, and allows mortality rates to differ between sexes. Furthermore, local density dependence induces a strong Allee effect, implying that the initial population must be sufficiently large to avert rapid extinction. We address three different initial spatial distributions for the introduced individuals; for each we minimize the associated cost, constrained by the requirement that the species must be restored throughout the habitat. First, we consider spatially inhomogeneous, unstable stationary solutions of the model’s equations as plausible candidates for small restoration cost. Second, we use numerical simulations to find the smallest rectangular cluster, enclosing a spatially homogeneous population density, that minimizes the cost of assured restoration. Finally, by employing simulated annealing, we minimize restoration cost among all possible initial spatial distributions of females and males. For biased sex ratios, or for a significant between-sex difference in mortality, we find that sex-specific spatial distributions minimize the cost. But as long as the sex ratio maximizes the local equilibrium density for given mortality rates, a common homogeneous distribution for both sexes that spans a critical distance yields a similarly low cost. PMID:24204810

  13. Population Health Impact and Cost-Effectiveness of Tuberculosis Diagnosis with Xpert MTB/RIF: A Dynamic Simulation and Economic Evaluation

    PubMed Central

    Menzies, Nicolas A.; Cohen, Ted; Lin, Hsien-Ho; Murray, Megan; Salomon, Joshua A.

    2012-01-01

    Background The Xpert MTB/RIF test enables rapid detection of tuberculosis (TB) and rifampicin resistance. The World Health Organization recommends Xpert for initial diagnosis in individuals suspected of having multidrug-resistant TB (MDR-TB) or HIV-associated TB, and many countries are moving quickly toward adopting Xpert. As roll-out proceeds, it is essential to understand the potential health impact and cost-effectiveness of diagnostic strategies based on Xpert. Methods and Findings We evaluated potential health and economic consequences of implementing Xpert in five southern African countries—Botswana, Lesotho, Namibia, South Africa, and Swaziland—where drug resistance and TB-HIV coinfection are prevalent. Using a calibrated, dynamic mathematical model, we compared the status quo diagnostic algorithm, emphasizing sputum smear, against an algorithm incorporating Xpert for initial diagnosis. Results were projected over 10- and 20-y time periods starting from 2012. Compared to status quo, implementation of Xpert would avert 132,000 (95% CI: 55,000–284,000) TB cases and 182,000 (97,000–302,000) TB deaths in southern Africa over the 10 y following introduction, and would reduce prevalence by 28% (14%–40%) by 2022, with more modest reductions in incidence. Health system costs are projected to increase substantially with Xpert, by US$460 million (294–699 million) over 10 y. Antiretroviral therapy for HIV represents a substantial fraction of these additional costs, because of improved survival in TB/HIV-infected populations through better TB case-finding and treatment. Costs for treating MDR-TB are also expected to rise significantly with Xpert scale-up. Relative to status quo, Xpert has an estimated cost-effectiveness of US$959 (633–1,485) per disability-adjusted life-year averted over 10 y. Across countries, cost-effectiveness ratios ranged from US$792 (482–1,785) in Swaziland to US$1,257 (767–2,276) in Botswana. Assessing outcomes over a 10-y period

  14. Dengue Dynamics and Vaccine Cost-Effectiveness Analysis in the Philippines

    PubMed Central

    Shim, Eunha

    2016-01-01

    Dengue is one of the most problematic vector-borne diseases in the Philippines, with an estimated 842,867 cases resulting in medical costs of $345 million U.S. dollars annually. In December 2015, the first dengue vaccine, known as chimeric yellow fever virus–dengue virus tetravalent dengue vaccine, was approved for use in the Philippines and is given to children 9 years of age. To estimate the cost-effectiveness of dengue vaccination in the Philippines, we developed an age-structured model of dengue transmission and vaccination. Using our model, we compared two vaccination scenarios entailing routine vaccination programs both with and without catch-up vaccination. Our results indicate that the higher the cost of vaccination, the less cost-effective the dengue vaccination program. With the current dengue vaccination program that vaccinates children 9 years of age, dengue vaccination is cost-effective for vaccination costs up to $70 from a health-care perspective and up to $75 from a societal perspective. Under a favorable scenario consisting of 1 year of catch-up vaccinations that target children 9–15 years of age, followed by regular vaccination of 9-year-old children, vaccination is cost-effective at costs up to $72 from a health-care perspective and up to $78 from a societal perspective. In general, dengue vaccination is expected to reduce the incidence of both dengue fever and dengue hemorrhagic fever /dengue shock syndrome. Our results demonstrate that even at relatively low vaccine efficacies, age-targeted vaccination may still be cost-effective provided the vaccination cost is sufficiently low. PMID:27601519

  15. Effects of wildlife and cattle on tick abundance in central Kenya.

    PubMed

    Keesing, Felicia; Allan, Brian F; Young, Truman P; Ostfeld, Richard S

    2013-09-01

    In African savannas, large mammals, both wild and domestic, support an abundant and diverse population of tick ectoparasites. Because of the density of ticks and the many pathogens that they vector, cattle in East Africa are often treated with acaricides. While acaricides are known to be effective at reducing tick burdens on cattle, their effects on the overall abundance and community composition of ticks in savanna ecosystems are less well understood. It is also not known how well tick populations can be maintained in the absence of large mammals. We evaluated the effects of wildlife and of acaricide-treated cattle on host-seeking tick populations in a long-term, exclusion experiment in central Kenya. Over seven years, we sampled larval, nymphal, and adult ticks monthly on replicated treatment plots that controlled for the presence of cattle and for the presence of two guilds of large wild mammals: megaherbivores (giraffes and elephants) and all other large wild herbivores (> 15 kg). Two species of ticks were found in this habitat; across all surveys, 93% were Rhipicephalus pulchellus and 7% were R. praetextatus. The presence of acaricide-treated cattle dramatically reduced the abundance of host-seeking nymphal and adult ticks but did not affect the abundance of host-seeking larval ticks. The abundance of larval ticks was determined by the presence of large wild mammals, which appear to import gravid female ticks into the experimental plots. On plots with no large mammals, either wild or domestic, larval and nymphal ticks were rare. Adult R. pulchellus were most abundant in plots that allowed wildlife but excluded cattle. Adult R. praetextatus were relatively abundant in plots without any large mammals. These differences suggest that these ticks utilize different members of the host community. The reduction in ticks that results from the presence of acaricide-treated cattle has potential health benefits for humans and wildlife, but these benefits must be weighed

  16. Seasonal temperature and precipitation regulate brook trout young-of-the-year abundance and population dynamics

    USGS Publications Warehouse

    Kanno, Yoichiro; Pregler, Kasey C.; Hitt, Nathaniel P.; Letcher, Benjamin H.; Hocking, Daniel; Wofford, John E.B.

    2015-01-01

    Our results indicate that YOY abundance is a key driver of brook trout population dynamics that is mediated by seasonal weather patterns. A reliable assessment of climate change impacts on brook trout needs to account for how alternations in seasonal weather patterns impact YOY abundance and how such relationships may differ across the range of brook trout distribution.

  17. Dengue Dynamics and Vaccine Cost-Effectiveness Analysis in the Philippines.

    PubMed

    Shim, Eunha

    2016-11-02

    Dengue is one of the most problematic vector-borne diseases in the Philippines, with an estimated 842,867 cases resulting in medical costs of $345 million U.S. dollars annually. In December 2015, the first dengue vaccine, known as chimeric yellow fever virus-dengue virus tetravalent dengue vaccine, was approved for use in the Philippines and is given to children 9 years of age. To estimate the cost-effectiveness of dengue vaccination in the Philippines, we developed an age-structured model of dengue transmission and vaccination. Using our model, we compared two vaccination scenarios entailing routine vaccination programs both with and without catch-up vaccination. Our results indicate that the higher the cost of vaccination, the less cost-effective the dengue vaccination program. With the current dengue vaccination program that vaccinates children 9 years of age, dengue vaccination is cost-effective for vaccination costs up to $70 from a health-care perspective and up to $75 from a societal perspective. Under a favorable scenario consisting of 1 year of catch-up vaccinations that target children 9-15 years of age, followed by regular vaccination of 9-year-old children, vaccination is cost-effective at costs up to $72 from a health-care perspective and up to $78 from a societal perspective. In general, dengue vaccination is expected to reduce the incidence of both dengue fever and dengue hemorrhagic fever /dengue shock syndrome. Our results demonstrate that even at relatively low vaccine efficacies, age-targeted vaccination may still be cost-effective provided the vaccination cost is sufficiently low. © The American Society of Tropical Medicine and Hygiene.

  18. Low-cost, compact, and robust gas abundance sensor package

    NASA Astrophysics Data System (ADS)

    Tran, Dat; Nehmetallah, George; Gorius, Nicolas; Ferguson, Frank T.; Esper, Jaime; Johnson, Natasha M.; Aslam, Shahid; Nixon, Conor

    2018-05-01

    Gas Abundance Sensor Package (GASP) is a stand-alone scientific instrument that has the capability to measure the concentration of target gases based on a non-dispersive infrared sensor system along with atmospheric reference parameters. The main objective of this work is to develop a GASP system which takes advantage of available technologies and off-the-shelf components to provide a cost-effective solution for localized sampling of gas concentrations. GASP will enable scientists to study the atmosphere and will identify the conditions of the target's planetary local environment. Moreover, due to a recent trend of miniaturization of electronic components and thermopiles detectors, a small size and robust instrument with a reduction in power consumption is developed in this work. This allows GASP to be easily integrated into a variety of small space vehicles such as CubeSats or small satellite system, especially the Micro-Reentry Capsule (MIRCA) prototype vehicle. This prototype is one of the most advanced concepts of small satellites that has the capability to survive the rapid dive into the atmosphere of a planet. In this paper, a fully-operational instrument system will be developed and tested in the laboratory environment as well as flight preparation for a field test of the instrument suite will be described.

  19. Species composition, abundance, and seasonal dynamics of stink bugs (Hemiptera: Pentatomidae) in Minnesota soybean fields.

    PubMed

    Koch, Robert L; Pahs, Tiffany

    2014-08-01

    Stink bugs (Hemiptera: Pentatomidae) have historically not been pests of soybean in Minnesota. In response to the invasion of Halyomorpha halys (Stål) and reports of increasing abundance of species native to North America, a state-wide survey of soybean was conducted over 3 yr in Minnesota to determine species composition, abundance, and seasonal dynamics of Pentatomidae associated with soybean. Fourteen species of Pentatomidae (12 herbivorous and two predatory) were collected from soybean. H. halys was not detected in this survey. Among the herbivorous species found, adults of Euschistus variolarius (Palisot de Beauvois) had the greatest relative abundance (60.51%) and frequency of detection (18.44%), followed by Euschistus servus euschistoides (Say) (19.37 and 3.04%, respectively) and Chinavia hilaris (Say) (5.50 and 1.69%, respectively). Abundance of herbivorous nymphs and adults exceeded an economic threshold (20 nymphs and adults per 100 sweeps) in 0.82% of fields in 2012 but not in 2011 or 2013. The frequency of detection of herbivorous species and ratio of nymphs to adults increased with increasing reproductive growth stage of soybean. In two of three years, herbivorous adults were more abundant in the edge compared with interior of fields. Two predatory Pentatomidae, Podisus maculiventris (Say) and Podisus placidus Uhler, comprised 5.95 and 1.62% of the pentatomid adults. Though the species composition of Pentatomidae in Minnesota soybean differs from that in eastern and southern states, the spatial (i.e., greater abundance near field edge) and seasonal dynamics (i.e., increasing abundance and reproduction with increasing reproductive maturity of soybean) in soybean appear similar.

  20. The Impact of Detoxification Costs and Predation Risk on Foraging: Implications for Mimicry Dynamics

    PubMed Central

    Skelhorn, John; Rowe, Candy; Ruxton, Graeme D.; Higginson, Andrew D.

    2017-01-01

    Prey often evolve defences to deter predators, such as noxious chemicals including toxins. Toxic species often advertise their defence to potential predators by distinctive sensory signals. Predators learn to associate toxicity with the signals of these so-called aposematic prey, and may avoid them in future. In turn, this selects for mildly toxic prey to mimic the appearance of more toxic prey. Empirical evidence shows that mimicry could be either beneficial (‘Mullerian’) or detrimental (‘quasi-Batesian’) to the highly toxic prey, but the factors determining which are unknown. Here, we use state-dependent models to explore how tri-trophic interactions could influence the evolution of prey defences. We consider how predation risk affects predators’ optimal foraging strategies on aposematic prey, and explore the resultant impact this has on mimicry dynamics between unequally defended species. In addition, we also investigate how the potential energetic cost of metabolising a toxin can alter the benefits to eating toxic prey and thus impact on predators’ foraging decisions. Our model predicts that both how predators perceive their own predation risk, and the cost of detoxification, can have significant, sometimes counterintuitive, effects on the foraging decisions of predators. For example, in some conditions predators should: (i) avoid prey they know to be undefended, (ii) eat more mildly toxic prey as detoxification costs increase, (iii) increase their intake of highly toxic prey as the abundance of undefended prey increases. These effects mean that the relationship between a mimic and its model can qualitatively depend on the density of alternative prey and the cost of metabolising toxins. In addition, these effects are mediated by the predators’ own predation risk, which demonstrates that, higher trophic levels than previously considered can have fundamental impacts on interactions among aposematic prey species. PMID:28045959

  1. Can Occupancy–Abundance Models Be Used to Monitor Wolf Abundance?

    PubMed Central

    Latham, M. Cecilia; Latham, A. David M.; Webb, Nathan F.; Mccutchen, Nicole A.; Boutin, Stan

    2014-01-01

    Estimating the abundance of wild carnivores is of foremost importance for conservation and management. However, given their elusive habits, direct observations of these animals are difficult to obtain, so abundance is more commonly estimated from sign surveys or radio-marked individuals. These methods can be costly and difficult, particularly in large areas with heavy forest cover. As an alternative, recent research has suggested that wolf abundance can be estimated from occupancy–abundance curves derived from “virtual” surveys of simulated wolf track networks. Although potentially more cost-effective, the utility of this approach hinges on its robustness to violations of its assumptions. We assessed the sensitivity of the occupancy–abundance approach to four assumptions: variation in wolf movement rates, changes in pack cohesion, presence of lone wolves, and size of survey units. Our simulations showed that occupancy rates and wolf pack abundances were biased high if track surveys were conducted when wolves made long compared to short movements, wolf packs were moving as multiple hunting units as opposed to a cohesive pack, and lone wolves were moving throughout the surveyed landscape. We also found that larger survey units (400 and 576 km2) were more robust to changes in these factors than smaller survey units (36 and 144 km2). However, occupancy rates derived from large survey units rapidly reached an asymptote at 100% occupancy, suggesting that these large units are inappropriate for areas with moderate to high wolf densities (>15 wolves/1,000 km2). Virtually-derived occupancy–abundance relationships can be a useful method for monitoring wolves and other elusive wildlife if applied within certain constraints, in particular biological knowledge of the surveyed species needs to be incorporated into the design of the occupancy surveys. Further, we suggest that the applicability of this method could be extended by directly incorporating some of its

  2. Monitoring the abundance of plastic debris in the marine environment.

    PubMed

    Ryan, Peter G; Moore, Charles J; van Franeker, Jan A; Moloney, Coleen L

    2009-07-27

    Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally.

  3. Monitoring the abundance of plastic debris in the marine environment

    PubMed Central

    Ryan, Peter G.; Moore, Charles J.; van Franeker, Jan A.; Moloney, Coleen L.

    2009-01-01

    Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally. PMID:19528052

  4. Dynamic Cost Risk Assessment for Controlling the Cost of Naval Vessels

    DTIC Science & Technology

    2008-04-23

    for each individual RRA at the start of the project are depicted in Figures 2a and 2b, respectively. The PDFs are multimodal and cannot be...underestimates cost. 7 Probabilistic cost analysis A physician metaphor Adapted from Yacov Y. Haimes, NPS 2007 8 Dynamic cost risk management A physician... metaphor Adapted from Yacov Y. Haimes, NPS 2007 9 Sources of cost uncertainty Macroscopic analysis Economic, Materials & Labor, Learning rates

  5. Cost-Effectiveness of Adolescent Pertussis Vaccination for The Netherlands: Using an Individual-Based Dynamic Model

    PubMed Central

    de Vries, Robin; Kretzschmar, Mirjam; Schellekens, Joop F. P.; Versteegh, Florens G. A.; Westra, Tjalke A.; Roord, John J.; Postma, Maarten J.

    2010-01-01

    Background Despite widespread immunization programs, a clear increase in pertussis incidence is apparent in many developed countries during the last decades. Consequently, additional immunization strategies are considered to reduce the burden of disease. The aim of this study is to design an individual-based stochastic dynamic framework to model pertussis transmission in the population in order to predict the epidemiologic and economic consequences of the implementation of universal booster vaccination programs. Using this framework, we estimate the cost-effectiveness of universal adolescent pertussis booster vaccination at the age of 12 years in the Netherlands. Methods/Principal Findings We designed a discrete event simulation (DES) model to predict the epidemiological and economic consequences of implementing universal adolescent booster vaccination. We used national age-specific notification data over the period 1996–2000—corrected for underreporting—to calibrate the model assuming a steady state situation. Subsequently, booster vaccination was introduced. Input parameters of the model were derived from literature, national data sources (e.g. costing data, incidence and hospitalization data) and expert opinions. As there is no consensus on the duration of immunity acquired by natural infection, we considered two scenarios for this duration of protection (i.e. 8 and 15 years). In both scenarios, total pertussis incidence decreased as a result of adolescent vaccination. From a societal perspective, the cost-effectiveness was estimated at €4418/QALY (range: 3205–6364 € per QALY) and €6371/QALY (range: 4139–9549 € per QALY) for the 8- and 15-year protection scenarios, respectively. Sensitivity analyses revealed that the outcomes are most sensitive to the quality of life weights used for pertussis disease. Conclusions/Significance To our knowledge we designed the first individual-based dynamic framework to model pertussis transmission in the

  6. Evaluating noninvasive genetic sampling techniques to estimate large carnivore abundance.

    PubMed

    Mumma, Matthew A; Zieminski, Chris; Fuller, Todd K; Mahoney, Shane P; Waits, Lisette P

    2015-09-01

    Monitoring large carnivores is difficult because of intrinsically low densities and can be dangerous if physical capture is required. Noninvasive genetic sampling (NGS) is a safe and cost-effective alternative to physical capture. We evaluated the utility of two NGS methods (scat detection dogs and hair sampling) to obtain genetic samples for abundance estimation of coyotes, black bears and Canada lynx in three areas of Newfoundland, Canada. We calculated abundance estimates using program capwire, compared sampling costs, and the cost/sample for each method relative to species and study site, and performed simulations to determine the sampling intensity necessary to achieve abundance estimates with coefficients of variation (CV) of <10%. Scat sampling was effective for both coyotes and bears and hair snags effectively sampled bears in two of three study sites. Rub pads were ineffective in sampling coyotes and lynx. The precision of abundance estimates was dependent upon the number of captures/individual. Our simulations suggested that ~3.4 captures/individual will result in a < 10% CV for abundance estimates when populations are small (23-39), but fewer captures/individual may be sufficient for larger populations. We found scat sampling was more cost-effective for sampling multiple species, but suggest that hair sampling may be less expensive at study sites with limited road access for bears. Given the dependence of sampling scheme on species and study site, the optimal sampling scheme is likely to be study-specific warranting pilot studies in most circumstances. © 2015 John Wiley & Sons Ltd.

  7. Interactive effects of wildfire, forest management, and isolation on amphibian and parasite abundance

    USGS Publications Warehouse

    Hossack, Blake R.; Corn, P. Stephen; Winsor H. Lowe,; R. Kenneth Honeycutt,; Sean A. Parks,

    2013-01-01

    Projected increases in wildfire and other climate-driven disturbances will affect populations and communities worldwide, including host–parasite relationships. Research in temperate forests has shown that wildfire can negatively affect amphibians, but this research has occurred primarily outside of managed landscapes where interactions with human disturbances could result in additive or synergistic effects. Furthermore, parasites represent a large component of biodiversity and can affect host fitness and population dynamics, yet they are rarely included in studies of how vertebrate hosts respond to disturbance. To determine how wildfire affects amphibians and their parasites, and whether effects differ between protected and managed landscapes, we compared abundance of two amphibians and two nematodes relative to wildfire extent and severity around wetlands in neighboring protected and managed forests (Montana, USA). Population sizes of adult, male long-toed salamanders (Ambystoma macrodactylum) decreased with increased burn severity, with stronger negative effects on isolated populations and in managed forests. In contrast, breeding population sizes of Columbia spotted frogs (Rana luteiventris) increased with burn extent in both protected and managed protected forests. Path analysis showed that the effects of wildfire on the two species of nematodes were consistent with differences in their life history and transmission strategies and the responses of their hosts. Burn severity indirectly reduced abundance of soil-transmitted Cosmocercoides variabilis through reductions in salamander abundance. Burn severity also directly reduced C. variabilis abundance, possibly though changes in soil conditions. For the aquatically transmitted nematode Gyrinicola batrachiensis, the positive effect of burn extent on density of Columbia spotted frog larvae indirectly increased parasite abundance. Our results show that effects of wildfire on amphibians depend upon burn extent

  8. Empirical phylogenies and species abundance distributions are consistent with preequilibrium dynamics of neutral community models with gene flow.

    PubMed

    Bonnet-Lebrun, Anne-Sophie; Manica, Andrea; Eriksson, Anders; Rodrigues, Ana S L

    2017-05-01

    Community characteristics reflect past ecological and evolutionary dynamics. Here, we investigate whether it is possible to obtain realistically shaped modeled communities-that is with phylogenetic trees and species abundance distributions shaped similarly to typical empirical bird and mammal communities-from neutral community models. To test the effect of gene flow, we contrasted two spatially explicit individual-based neutral models: one with protracted speciation, delayed by gene flow, and one with point mutation speciation, unaffected by gene flow. The former produced more realistic communities (shape of phylogenetic tree and species-abundance distribution), consistent with gene flow being a key process in macro-evolutionary dynamics. Earlier models struggled to capture the empirically observed branching tempo in phylogenetic trees, as measured by the gamma statistic. We show that the low gamma values typical of empirical trees can be obtained in models with protracted speciation, in preequilibrium communities developing from an initially abundant and widespread species. This was even more so in communities sampled incompletely, particularly if the unknown species are the youngest. Overall, our results demonstrate that the characteristics of empirical communities that we have studied can, to a large extent, be explained through a purely neutral model under preequilibrium conditions. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  9. Melanoma costs: a dynamic model comparing estimated overall costs of various clinical stages.

    PubMed

    Alexandrescu, Doru Traian

    2009-11-15

    adjuvant treatment with IFN-alpha ($75,955.18), palliative care ($14,500), and administration of chemotherapy ($1,967.10 for a triple combination of agents); there are even higher costs for biochemotherapy, the new tyrosine kinase and antiangiogenic drugs, and hospital treatment of neutropenic fever ($1,535.00 to $1,800.00/day). There is a significant cost decrement when melanoma is diagnosed at an earlier stage, with a T4b lesion being approximately 2200 percent more expensive to diagnose and treat than an early in situ melanoma and 1000 percent more expensive than a stage T1a tumor. Although a direct comparison with other cancers would require the use of the same dynamic model, it is apparent that the high costs of melanoma care places it at the top of the most expensive cancers to diagnose, follow, and treat. These high costs for advanced-stage melanoma warrant an increased emphasis on developing effective strategies for its early diagnosis and treatment.

  10. Costing the distribution of insecticide-treated nets: a review of cost and cost-effectiveness studies to provide guidance on standardization of costing methodology

    PubMed Central

    Kolaczinski, Jan; Hanson, Kara

    2006-01-01

    Background Insecticide-treated nets (ITNs) are an effective and cost-effective means of malaria control. Scaling-up coverage of ITNs is challenging. It requires substantial resources and there are a number of strategies to choose from. Information on the cost of different strategies is still scarce. To guide the choice of a delivery strategy (or combination of strategies), reliable and standardized cost information for the different options is required. Methods The electronic online database PubMed was used for a systematic search of the published English literature on costing and economic evaluations of ITN distribution programmes. The keywords used were: net, bednet, insecticide, treated, ITN, cost, effectiveness, economic and evaluation. Identified papers were analysed to determine and evaluate the costing methods used. Methods were judged against existing standards of cost analysis to arrive at proposed standards for undertaking and presenting cost analyses. Results Cost estimates were often not readily comparable or could not be adjusted to a different context. This resulted from the wide range of methods applied and measures of output chosen. Most common shortcomings were the omission of certain costs and failure to adjust financial costs to generate economic costs. Generalisability was hampered by authors not reporting quantities and prices of resources separately and not examining the sensitivity of their results to variations in underlying assumptions. Conclusion The observed shortcomings have arisen despite the abundance of literature and guidelines on costing of health care interventions. This paper provides ITN specific recommendations in the hope that these will help to standardize future cost estimates. PMID:16681856

  11. Costing the distribution of insecticide-treated nets: a review of cost and cost-effectiveness studies to provide guidance on standardization of costing methodology.

    PubMed

    Kolaczinski, Jan; Hanson, Kara

    2006-05-08

    Insecticide-treated nets (ITNs) are an effective and cost-effective means of malaria control. Scaling-up coverage of ITNs is challenging. It requires substantial resources and there are a number of strategies to choose from. Information on the cost of different strategies is still scarce. To guide the choice of a delivery strategy (or combination of strategies), reliable and standardized cost information for the different options is required. The electronic online database PubMed was used for a systematic search of the published English literature on costing and economic evaluations of ITN distribution programmes. The keywords used were: net, bednet, insecticide, treated, ITN, cost, effectiveness, economic and evaluation. Identified papers were analysed to determine and evaluate the costing methods used. Methods were judged against existing standards of cost analysis to arrive at proposed standards for undertaking and presenting cost analyses. Cost estimates were often not readily comparable or could not be adjusted to a different context. This resulted from the wide range of methods applied and measures of output chosen. Most common shortcomings were the omission of certain costs and failure to adjust financial costs to generate economic costs. Generalisability was hampered by authors not reporting quantities and prices of resources separately and not examining the sensitivity of their results to variations in underlying assumptions. The observed shortcomings have arisen despite the abundance of literature and guidelines on costing of health care interventions. This paper provides ITN specific recommendations in the hope that these will help to standardize future cost estimates.

  12. FREQ-Seq: A Rapid, Cost-Effective, Sequencing-Based Method to Determine Allele Frequencies Directly from Mixed Populations

    PubMed Central

    Delaney, Nigel F.; Marx, Christopher J.

    2012-01-01

    Understanding evolutionary dynamics within microbial populations requires the ability to accurately follow allele frequencies through time. Here we present a rapid, cost-effective method (FREQ-Seq) that leverages Illumina next-generation sequencing for localized, quantitative allele frequency detection. Analogous to RNA-Seq, FREQ-Seq relies upon counts from the >105 reads generated per locus per time-point to determine allele frequencies. Loci of interest are directly amplified from a mixed population via two rounds of PCR using inexpensive, user-designed oligonucleotides and a bar-coded bridging primer system that can be regenerated in-house. The resulting bar-coded PCR products contain the adapters needed for Illumina sequencing, eliminating further library preparation. We demonstrate the utility of FREQ-Seq by determining the order and dynamics of beneficial alleles that arose as a microbial population, founded with an engineered strain of Methylobacterium, evolved to grow on methanol. Quantifying allele frequencies with minimal bias down to 1% abundance allowed effective analysis of SNPs, small in-dels and insertions of transposable elements. Our data reveal large-scale clonal interference during the early stages of adaptation and illustrate the utility of FREQ-Seq as a cost-effective tool for tracking allele frequencies in populations. PMID:23118913

  13. Effects of harvesting flowers from shrubs on the persistence and abundance of wild shrub populations at multiple spatial extents.

    PubMed

    Cabral, Juliano Sarmento; Bond, William J; Midgley, Guy F; Rebelo, Anthony G; Thuiller, Wilfried; Schurr, Frank M

    2011-02-01

    Wildflower harvesting is an economically important activity of which the ecological effects are poorly understood. We assessed how harvesting of flowers affects shrub persistence and abundance at multiple spatial extents. To this end, we built a process-based model to examine the mean persistence and abundance of wild shrubs whose flowers are subject to harvest (serotinous Proteaceae in the South African Cape Floristic Region). First, we conducted a general sensitivity analysis of how harvesting affects persistence and abundance at nested spatial extents. For most spatial extents and combinations of demographic parameters, persistence and abundance of flowering shrubs decreased abruptly once harvesting rate exceeded a certain threshold. At larger extents, metapopulations supported higher harvesting rates before their persistence and abundance decreased, but persistence and abundance also decreased more abruptly due to harvesting than at smaller extents. This threshold rate of harvest varied with species' dispersal ability, maximum reproductive rate, adult mortality, probability of extirpation or local extinction, strength of Allee effects, and carrying capacity. Moreover, spatial extent interacted with Allee effects and probability of extirpation because both these demographic properties affected the response of local populations to harvesting more strongly than they affected the response of metapopulations. Subsequently, we simulated the effects of harvesting on three Cape Floristic Region Proteaceae species and found that these species reacted differently to harvesting, but their persistence and abundance decreased at low rates of harvest. Our estimates of harvesting rates at maximum sustainable yield differed from those of previous investigations, perhaps because researchers used different estimates of demographic parameters, models of population dynamics, and spatial extent than we did. Good demographic knowledge and careful identification of the spatial extent

  14. Local Hotspots In The Gulf Of Maine: Spatial Overlap Between Dynamic Aggregations Of Primary Productivity And Fish Abundance

    NASA Astrophysics Data System (ADS)

    Ribera, M.

    2016-02-01

    Identification of biological hotspots may be a necessary step toward ecosystem-based management goals, as these often signal underlying processes that aggregate or stimulate resources in a particular location. However, previously used metrics to locate these hotspots are not easily adapted to local marine datasets, in part due to the high spatial and temporal variability of phytoplankton populations. While most fish species in temperate regions are well adapted to the seasonal variability of phytoplankton abundance, it is the variability beyond this predictable pattern (i.e. anomalies) that may heavily impact the abundance and spatial distribution of organisms higher up the food chain. The objective of this study was to identify local-scale biological hotspots in a region in the western side of the Gulf of Maine using remote sensing chlorophyll-a data (from MERIS sensor), and to study the spatial overlap between these hotspots and high concentrations of fish abundance (derived from VTR dataset). For this reason, we defined a new hotspot metric that identified as a hotspot any area that consistently exhibited high-magnitude anomalies through time, a sign of highly dynamic communities. We improved on previous indices by minimizing the effect that different means and variances across space may have on the results, a situation that often occurs when comparing coastal and offshore systems. Results show a significant spatial correlation between pelagic fish abundance and aggregations of primary productivity. Spatial correlations were also significant between benthic fish abundance and primary productivity hotspots, but only during spring months. We argue that this new hotspot index compliments existing global measures as it helps managers understand the dynamic characteristics of a complex marine system. It also provides a unique metric that is easily compared across space and between different trophic levels, which may facilitate future ecosystem-wide studies.

  15. Local Hotspots In The Gulf Of Maine: Spatial Overlap Between Dynamic Aggregations Of Primary Productivity And Fish Abundance

    NASA Astrophysics Data System (ADS)

    Ribera, M.

    2016-12-01

    Identification of biological hotspots may be a necessary step toward ecosystem-based management goals, as these often signal underlying processes that aggregate or stimulate resources in a particular location. However, previously used metrics to locate these hotspots are not easily adapted to local marine datasets, in part due to the high spatial and temporal variability of phytoplankton populations. While most fish species in temperate regions are well adapted to the seasonal variability of phytoplankton abundance, it is the variability beyond this predictable pattern (i.e. anomalies) that may heavily impact the abundance and spatial distribution of organisms higher up the food chain. The objective of this study was to identify local-scale biological hotspots in a region in the western side of the Gulf of Maine using remote sensing chlorophyll-a data (from MERIS sensor), and to study the spatial overlap between these hotspots and high concentrations of fish abundance (derived from VTR dataset). For this reason, we defined a new hotspot metric that identified as a hotspot any area that consistently exhibited high-magnitude anomalies through time, a sign of highly dynamic communities. We improved on previous indices by minimizing the effect that different means and variances across space may have on the results, a situation that often occurs when comparing coastal and offshore systems. Results show a significant spatial correlation between pelagic fish abundance and aggregations of primary productivity. Spatial correlations were also significant between benthic fish abundance and primary productivity hotspots, but only during spring months. We argue that this new hotspot index compliments existing global measures as it helps managers understand the dynamic characteristics of a complex marine system. It also provides a unique metric that is easily compared across space and between different trophic levels, which may facilitate future ecosystem-wide studies.

  16. The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling

    PubMed Central

    Connor, Jennie; Witten, Karen; Kearns, Robin; Rees, David; Woodward, Alistair

    2014-01-01

    Background: Shifting to active modes of transport in the trip to work can achieve substantial co-benefits for health, social equity, and climate change mitigation. Previous integrated modeling of transport scenarios has assumed active transport mode share and has been unable to incorporate acknowledged system feedbacks. Objectives: We compared the effects of policies to increase bicycle commuting in a car-dominated city and explored the role of participatory modeling to support transport planning in the face of complexity. Methods: We used system dynamics modeling (SDM) to compare realistic policies, incorporating feedback effects, nonlinear relationships, and time delays between variables. We developed a system dynamics model of commuter bicycling through interviews and workshops with policy, community, and academic stakeholders. We incorporated best available evidence to simulate five policy scenarios over the next 40 years in Auckland, New Zealand. Injury, physical activity, fuel costs, air pollution, and carbon emissions outcomes were simulated. Results: Using the simulation model, we demonstrated the kinds of policies that would likely be needed to change a historical pattern of decline in cycling into a pattern of growth that would meet policy goals. Our model projections suggest that transforming urban roads over the next 40 years, using best practice physical separation on main roads and bicycle-friendly speed reduction on local streets, would yield benefits 10–25 times greater than costs. Conclusions: To our knowledge, this is the first integrated simulation model of future specific bicycling policies. Our projections provide practical evidence that may be used by health and transport policy makers to optimize the benefits of transport bicycling while minimizing negative consequences in a cost-effective manner. The modeling process enhanced understanding by a range of stakeholders of cycling as a complex system. Participatory SDM can be a helpful method

  17. Climatic effects on mosquito abundance in Mediterranean wetlands

    PubMed Central

    2014-01-01

    Background The impact of climate change on vector-borne diseases is highly controversial. One of the principal points of debate is whether or not climate influences mosquito abundance, a key factor in disease transmission. Methods To test this hypothesis, we analysed ten years of data (2003–2012) from biweekly surveys to assess inter-annual and seasonal relationships between the abundance of seven mosquito species known to be pathogen vectors (West Nile virus, Usutu virus, dirofilariasis and Plasmodium sp.) and several climatic variables in two wetlands in SW Spain. Results Within-season abundance patterns were related to climatic variables (i.e. temperature, rainfall, tide heights, relative humidity and photoperiod) that varied according to the mosquito species in question. Rainfall during winter months was positively related to Culex pipiens and Ochlerotatus detritus annual abundances. Annual maximum temperatures were non-linearly related to annual Cx. pipiens abundance, while annual mean temperatures were positively related to annual Ochlerotatus caspius abundance. Finally, we modelled shifts in mosquito abundances using the A2 and B2 temperature and rainfall climate change scenarios for the period 2011–2100. While Oc. caspius, an important anthropophilic species, may increase in abundance, no changes are expected for Cx. pipiens or the salt-marsh mosquito Oc. detritus. Conclusions Our results highlight that the effects of climate are species-specific, place-specific and non-linear and that linear approaches will therefore overestimate the effect of climate change on mosquito abundances at high temperatures. Climate warming does not necessarily lead to an increase in mosquito abundance in natural Mediterranean wetlands and will affect, above all, species such as Oc. caspius whose numbers are not closely linked to rainfall and are influenced, rather, by local tidal patterns and temperatures. The final impact of changes in vector abundance on disease frequency

  18. The dynamic inducer as a cost-effective wind turbine system

    NASA Astrophysics Data System (ADS)

    Gyatt, G.; Zalay, A.

    The efficacy of dynamic inducer tip vanes, short airfoil sections attached perpendicularly at the outer end of wind turbine rotors, were investigated analytically and experimentally. The airfoil section is oriented to lift toward the center of the rotor, thereby forcing a greater flow toward the center of the actuator disk. Also, since the vortex shed by one tip vane posterior edge is exactly opposite in sign to the vortex produced at the anterior edge of the immediately preceeding vane, a synchronous state arises wherein drag on the tip vanes is eliminated. A numerical model was developed for the wind turbine power coefficient in a synchronous state. The simulation indicated that more kinetic energy than present in the actuator disk alone can be captured. Design features of the blades and fairing are described. Dynamic inducer WECS were projected to cost 20% less than equivalent conventional horizontal axis machines, while power augmentation can approach 70%, thus exceeding the Betz limit.

  19. The cost and cost-effectiveness of opportunistic screening for Chlamydia trachomatis in Ireland.

    PubMed

    Gillespie, Paddy; O'Neill, Ciaran; Adams, Elisabeth; Turner, Katherine; O'Donovan, Diarmuid; Brugha, Ruairi; Vaughan, Deirdre; O'Connell, Emer; Cormican, Martin; Balfe, Myles; Coleman, Claire; Fitzgerald, Margaret; Fleming, Catherine

    2012-04-01

    The objective of this study was to estimate the cost and cost-effectiveness of opportunistic screening for Chlamydia trachomatis in Ireland. Prospective cost analysis of an opportunistic screening programme delivered jointly in three types of healthcare facility in Ireland. Incremental cost-effectiveness analysis was performed using an existing dynamic modelling framework to compare screening to a control of no organised screening. A healthcare provider perspective was adopted with respect to costs and included the costs of screening and the costs of complications arising from untreated infection. Two outcome measures were examined: major outcomes averted, comprising cases of pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in women, neonatal conjunctivitis and pneumonia, and epididymitis in men; and quality-adjusted life-years (QALY) gained. Uncertainty was explored using sensitivity analyses and cost-effectiveness acceptability curves. The average cost per component of screening was estimated at €26 per offer, €66 per negative case, €152 per positive case and €74 per partner notified and treated. The modelled screening scenario was projected to be more effective and more costly than the control strategy. The incremental cost per major outcomes averted was €6093, and the incremental cost per QALY gained was €94,717. For cost-effectiveness threshold values of €45,000 per QALY gained and lower, the probability of the screening being cost effective was estimated at <1%. An opportunistic chlamydia screening programme, as modelled in this study, would be expensive to implement nationally and is unlikely to be judged cost effective by policy makers in Ireland.

  20. Differential effects of habitat complexity, predators and competitors on abundance of juvenile and adult coral reef fishes.

    PubMed

    Almany, Glenn R

    2004-09-01

    Greater structural complexity is often associated with greater abundance and diversity, perhaps because high complexity habitats reduce predation and competition. Using 16 spatially isolated live-coral reefs in the Bahamas, I examined how abundance of juvenile (recruit) and adult (non-recruit) fishes was affected by two factors: (1) structural habitat complexity and (2) the presence of predators and interference competitors. Manipulating the abundance of low and high complexity corals created two levels of habitat complexity, which was cross-factored with the presence or absence of resident predators (sea basses and moray eels) plus interference competitors (territorial damselfishes). Over 60 days, predators and competitors greatly reduced recruit abundance regardless of habitat complexity, but did not affect adult abundance. In contrast, increased habitat complexity had a strong positive effect on adult abundance and a weak positive effect on recruit abundance. Differential responses of recruits and adults may be related to the differential effects of habitat complexity on their primary predators. Sedentary recruits are likely most preyed upon by small resident predators that ambush prey, while larger adult fishes that forage widely and use reefs primarily for shelter are likely most preyed upon by large transient predators that chase prey. Increased habitat complexity may have inhibited foraging by transient predators but not resident predators. Results demonstrate the importance of habitat complexity to community dynamics, which is of concern given the accelerated degradation of habitats worldwide.

  1. The Potential Cost Effectiveness of Different Dengue Vaccination Programmes in Malaysia: A Value-Based Pricing Assessment Using Dynamic Transmission Mathematical Modelling.

    PubMed

    Shafie, Asrul Akmal; Yeo, Hui Yee; Coudeville, Laurent; Steinberg, Lucas; Gill, Balvinder Singh; Jahis, Rohani; Amar-Singh Hss

    2017-05-01

    Dengue disease poses a great economic burden in Malaysia. This study evaluated the cost effectiveness and impact of dengue vaccination in Malaysia from both provider and societal perspectives using a dynamic transmission mathematical model. The model incorporated sensitivity analyses, Malaysia-specific data, evidence from recent phase III studies and pooled efficacy and long-term safety data to refine the estimates from previous published studies. Unit costs were valued in $US, year 2013 values. Six vaccination programmes employing a three-dose schedule were identified as the most likely programmes to be implemented. In all programmes, vaccination produced positive benefits expressed as reductions in dengue cases, dengue-related deaths, life-years lost, disability-adjusted life-years and dengue treatment costs. Instead of incremental cost-effectiveness ratios (ICERs), we evaluated the cost effectiveness of the programmes by calculating the threshold prices for a highly cost-effective strategy [ICER <1 × gross domestic product (GDP) per capita] and a cost-effective strategy (ICER between 1 and 3 × GDP per capita). We found that vaccination may be cost effective up to a price of $US32.39 for programme 6 (highly cost effective up to $US14.15) and up to a price of $US100.59 for programme 1 (highly cost effective up to $US47.96) from the provider perspective. The cost-effectiveness analysis is sensitive to under-reporting, vaccine protection duration and model time horizon. Routine vaccination for a population aged 13 years with a catch-up cohort aged 14-30 years in targeted hotspot areas appears to be the best-value strategy among those investigated. Dengue vaccination is a potentially good investment if the purchaser can negotiate a price at or below the cost-effective threshold price.

  2. Quantum ring-polymer contraction method: Including nuclear quantum effects at no additional computational cost in comparison to ab initio molecular dynamics

    NASA Astrophysics Data System (ADS)

    John, Christopher; Spura, Thomas; Habershon, Scott; Kühne, Thomas D.

    2016-04-01

    We present a simple and accurate computational method which facilitates ab initio path-integral molecular dynamics simulations, where the quantum-mechanical nature of the nuclei is explicitly taken into account, at essentially no additional computational cost in comparison to the corresponding calculation using classical nuclei. The predictive power of the proposed quantum ring-polymer contraction method is demonstrated by computing various static and dynamic properties of liquid water at ambient conditions using density functional theory. This development will enable routine inclusion of nuclear quantum effects in ab initio molecular dynamics simulations of condensed-phase systems.

  3. Costs for switching partners reduce network dynamics but not cooperative behaviour

    PubMed Central

    Bednarik, Peter; Fehl, Katrin; Semmann, Dirk

    2014-01-01

    Social networks represent the structuring of interactions between group members. Above all, many interactions are profoundly cooperative in humans and other animals. In accordance with this natural observation, theoretical work demonstrates that certain network structures favour the evolution of cooperation. Yet, recent experimental evidence suggests that static networks do not enhance cooperative behaviour in humans. By contrast, dynamic networks do foster cooperation. However, costs associated with dynamism such as time or resource investments in finding and establishing new partnerships have been neglected so far. Here, we show that human participants are much less likely to break links when costs arise for building new links. Especially, when costs were high, the network was nearly static. Surprisingly, cooperation levels in Prisoner's Dilemma games were not affected by reduced dynamism in social networks. We conclude that the mere potential to quit collaborations is sufficient in humans to reach high levels of cooperative behaviour. Effects of self-structuring processes or assortment on the network played a minor role: participants simply adjusted their cooperative behaviour in response to the threats of losing a partner or of being expelled. PMID:25122233

  4. Comparison of harvest scenarios for the cost-effective suppression of Lake Trout in Swan Lake, Montana

    USGS Publications Warehouse

    Syslo, John M.; Guy, Christopher S.; Cox, Benjamin S.

    2013-01-01

    Given the large amount of resources required for long-term control or eradication projects, it is important to assess strategies and associated costs and outcomes before a particular plan is implemented. We developed a population model to assess the cost-effectiveness of mechanical removal strategies for suppressing long-term abundance of nonnative Lake Trout Salvelinus namaycush in Swan Lake, Montana. We examined the efficacy of targeting life stages (i.e., juveniles or adults) using temporally pulsed fishing effort for reducing abundance and program cost. Exploitation rates were high (0.80 for juveniles and 0.68 for adults) compared with other lakes in the western USA with Lake Trout suppression programs. Harvesting juveniles every year caused the population to decline, whereas harvesting only adults caused the population to increase above carrying capacity. Simultaneous harvest of juveniles and adults was required to cause the population to collapse (i.e., 95% reduction relative to unharvested abundance) with 95% confidence. The population could collapse within 15 years for a total program cost of US$1,578,480 using the most aggressive scenario. Substantial variation in cost existed among harvest scenarios for a given reduction in abundance; however, total program cost was minimized when collapse was rapid. Our approach provides a useful case study for evaluating long-term mechanical removal options for fish populations that are not likely to be eradicated.

  5. Combined effects of climate, predation, and density dependence on Greater and Lesser Scaup population dynamics

    USGS Publications Warehouse

    Ross, Beth E.; Hooten, Mevin B.; DeVink, Jean-Michel; Koons, David N.

    2015-01-01

    An understanding of species relationships is critical in the management and conservation of populations facing climate change, yet few studies address how climate alters species interactions and other population drivers. We use a long-term, broad-scale data set of relative abundance to examine the influence of climate, predators, and density dependence on the population dynamics of declining scaup (Aythya) species within the core of their breeding range. The state-space modeling approach we use applies to a wide range of wildlife species, especially populations monitored over broad spatiotemporal extents. Using this approach, we found that immediate snow cover extent in the preceding winter and spring had the strongest effects, with increases in mean snow cover extent having a positive effect on the local surveyed abundance of scaup. The direct effects of mesopredator abundance on scaup population dynamics were weaker, but the results still indicated a potential interactive process between climate and food web dynamics (mesopredators, alternative prey, and scaup). By considering climate variables and other potential effects on population dynamics, and using a rigorous estimation framework, we provide insight into complex ecological processes for guiding conservation and policy actions aimed at mitigating and reversing the decline of scaup.

  6. Thaumarchaeal amoA and nirK Gene Abundance Patterns Reveal Spatiotemporal Dynamics of Ammonia-oxidizing Archaeal Populations in Monterey Bay, CA

    NASA Astrophysics Data System (ADS)

    Tolar, B. B.; Reji, L.; Smith, J. M.; Chavez, F.; Francis, C.

    2016-12-01

    Thaumarchaeaota are among the most abundant microorganisms on the planet, and are significant players in the global nitrogen cycle. All cultivated members of the phylum are capable of performing the first and rate-limiting step of nitrification - the aerobic oxidation of ammonia to nitrite. In marine environments, ammonia-oxidizing archaea (AOA) have been found to greatly outnumber their bacterial counterparts. However, much about their ecology remains largely unknown. Monterey Bay, a non-estuarine embayment on the central California coast, is an ideal site for studying the dynamics of natural thaumarchaeal assemblages, given the highly dynamic nature of the Bay waters with seasonal upwelling episodes and the associated steep gradients in environmental variables. In the present study, we examined thaumarchaeal population dynamics in the upper Monterey Bay water column (0-500 m) using multiple molecular markers. Following high-resolution spatiotemporal sampling (i.e., up to 10 depths sampled monthly over a period of 2 years) at two stations in the Bay, we quantified thaumarchaeal functional genes - the ammonia monooxygenase (amoA) gene and its `shallow' and `deep' marine ecotypes, and variants of the marine nitrite reductase (nirK) gene. The abundances of both genes were regressed against environmental variables to gain insights into factors shaping their spatiotemporal dynamics in the Bay. Gene abundances at both stations varied with depth and season, with winter months generally having several orders of magnitude greater abundances. Statistical analyses point to differential controls on the gene abundances, with depth and temperature potentially being the major environmental determinants of thaumarchaeal population size. Our results also highlight the importance of employing multiple marker genes to gain a more highly resolved picture of thaumarchaeal population dynamics in complex environmental systems such as the coastal ocean.

  7. Contrasting effects of temperature and precipitation change on amphibian phenology, abundance and performance.

    PubMed

    Ficetola, Gentile Francesco; Maiorano, Luigi

    2016-07-01

    Climate change is determining a generalized phenological advancement, and amphibians are among the taxa showing the strongest phenological responsiveness to warming temperatures. Amphibians are strongly influenced by climate change, but we do not have a clear picture of how climate influences important parameters of amphibian populations, such as abundance, survival, breeding success and morphology. Furthermore, the relative impact of temperature and precipitation change remains underappreciated. We used Bayesian meta-analysis and meta-regression to quantify the impact of temperature and precipitation change on amphibian phenology, abundance, individual features and performance. We obtained effect sizes from studies performed in five continents. Temperature increase was the major driver of phenological advancement, while the impact of precipitation on phenology was weak. Conversely, population dynamics was mostly determined by precipitation: negative trends were associated with drying regimes. The impact of precipitation on abundance was particularly strong in tropical areas, while the importance of temperature was feeble. Both temperature and precipitation influenced parameters representing breeding performance, morphology, developmental rate and survival, but the response was highly heterogeneous among species. For instance, warming temperature increased body size in some species, and decreased size in others. Similarly, rainy periods increased survival of some species and reduced the survival of others. Our study showed contrasting impacts of temperature and precipitation changes on amphibian populations. Both climatic parameters strongly influenced amphibian performance, but temperature was the major determinant of the phenological changes, while precipitation had the major role on population dynamics, with alarming declines associated with drying trends.

  8. A dynamic model for costing disaster mitigation policies.

    PubMed

    Altay, Nezih; Prasad, Sameer; Tata, Jasmine

    2013-07-01

    The optimal level of investment in mitigation strategies is usually difficult to ascertain in the context of disaster planning. This research develops a model to provide such direction by relying on cost of quality literature. This paper begins by introducing a static approach inspired by Joseph M. Juran's cost of quality management model (Juran, 1951) to demonstrate the non-linear trade-offs in disaster management expenditure. Next it presents a dynamic model that includes the impact of dynamic interactions of the changing level of risk, the cost of living, and the learning/investments that may alter over time. It illustrates that there is an optimal point that minimises the total cost of disaster management, and that this optimal point moves as governments learn from experience or as states get richer. It is hoped that the propositions contained herein will help policymakers to plan, evaluate, and justify voluntary disaster mitigation expenditures. © 2013 The Author(s). Journal compilation © Overseas Development Institute, 2013.

  9. The RAVE-on Catalog of Stellar Atmospheric Parameters and Chemical Abundances for Chemo-dynamic Studies in the Gaia Era

    NASA Astrophysics Data System (ADS)

    Casey, Andrew R.; Hawkins, Keith; Hogg, David W.; Ness, Melissa; Rix, Hans-Walter; Kordopatis, Georges; Kunder, Andrea; Steinmetz, Matthias; Koposov, Sergey; Enke, Harry; Sanders, Jason; Gilmore, Gerry; Zwitter, Tomaž; Freeman, Kenneth C.; Casagrande, Luca; Matijevič, Gal; Seabroke, George; Bienaymé, Olivier; Bland-Hawthorn, Joss; Gibson, Brad K.; Grebel, Eva K.; Helmi, Amina; Munari, Ulisse; Navarro, Julio F.; Reid, Warren; Siebert, Arnaud; Wyse, Rosemary

    2017-05-01

    The orbits, atmospheric parameters, chemical abundances, and ages of individual stars in the Milky Way provide the most comprehensive illustration of galaxy formation available. The Tycho-Gaia Astrometric Solution (TGAS) will deliver astrometric parameters for the largest ever sample of Milky Way stars, though its full potential cannot be realized without the addition of complementary spectroscopy. Among existing spectroscopic surveys, the RAdial Velocity Experiment (RAVE) has the largest overlap with TGAS (≳200,000 stars). We present a data-driven re-analysis of 520,781 RAVE spectra using The Cannon. For red giants, we build our model using high-fidelity APOGEE stellar parameters and abundances for stars that overlap with RAVE. For main sequence and sub-giant stars, our model uses stellar parameters from the K2/EPIC. We derive and validate effective temperature T eff, surface gravity log g, and chemical abundances of up to seven elements (O, Mg, Al, Si, Ca, Fe, and Ni). We report a total of 1,685,851 elemental abundances with a typical precision of 0.07 dex, a substantial improvement over previous RAVE data releases. The synthesis of RAVE-on and TGAS is the most powerful data set for chemo-dynamic analyses of the Milky Way ever produced.

  10. Temporal Dynamics of Abundance and Composition of Nitrogen-Fixing Communities across Agricultural Soils

    PubMed Central

    Pereira e Silva, Michele C.; Schloter-Hai, Brigitte; Schloter, Michael; van Elsas, Jan Dirk; Salles, Joana Falcão

    2013-01-01

    Background Despite the fact that the fixation of nitrogen is one of the most significant nutrient processes in the terrestrial ecosystem, a thorough study of the spatial and temporal patterns in the abundance and distribution of N-fixing communities has been missing so far. Methodology/Principal Findings In order to understand the dynamics of diazotrophic communities and their resilience to external changes, we quantified the abundance and characterized the bacterial community structures based on the nifH gene, using real-time PCR, PCR-DGGE and 454-pyrosequencing, across four representative Dutch soils during one growing season. In general, higher nifH gene copy numbers were observed in soils with higher pH than in those with lower pH, but lower numbers were related to increased nitrate and ammonium levels. Results from nifH gene pyrosequencing confirmed the observed PCR-DGGE patterns, which indicated that the N fixers are highly dynamic across time, shifting around 60%. Forward selection on CCA analysis identified N availability as the main driver of these variations, as well as of the evenness of the communities, leading to very unequal communities. Moreover, deep sequencing of the nifH gene revealed that sandy soils (B and D) had the lowest percentage of shared OTUs across time, compared with clayey soils (G and K), indicating the presence of a community under constant change. Cosmopolitan nifH species (present throughout the season) were affiliated with Bradyrhizobium , Azospirillum and Methylocistis, whereas other species increased their abundances progressively over time, when appropriate conditions were met, as was notably the case for Paenibacilus and Burkholderia. Conclusions Our study provides the first in-depth pyrosequencing analysis of the N-fixing community at both spatial and temporal scales, providing insights into the cosmopolitan and specific portions of the nitrogen fixing bacterial communities in soil. PMID:24058578

  11. Social costs enforce honesty of a dynamic signal of motivation.

    PubMed

    Ligon, Russell A; McGraw, Kevin J

    2016-10-26

    Understanding the processes that promote signal reliability may provide important insights into the evolution of diverse signalling strategies among species. The signals that animals use to communicate must comprise mechanisms that prohibit or punish dishonesty, and social costs of dishonesty have been demonstrated for several fixed morphological signals (e.g. colour badges of birds and wasps). The costs maintaining the honesty of dynamic signals, which are more flexible and potentially cheatable, are unknown. Using an experimental manipulation of the dynamic visual signals used by male veiled chameleons (Chamaeleo calyptratus) during aggressive interactions, we tested the idea that the honesty of rapid colour change signals is maintained by social costs. Our results reveal that social costs are an important mechanism maintaining the honesty of these dynamic colour signals-'dishonest' chameleons whose experimentally manipulated coloration was incongruent with their contest behaviour received more physical aggression than 'honest' individuals. This is the first demonstration, to the best our knowledge, that the honesty of a dynamic signal of motivation-physiological colour change-can be maintained by the social costliness of dishonesty. Behavioural responses of signal receivers, irrespective of any specific detection mechanisms, therefore prevent chameleon cheaters from prospering. © 2016 The Author(s).

  12. Social costs enforce honesty of a dynamic signal of motivation

    PubMed Central

    McGraw, Kevin J.

    2016-01-01

    Understanding the processes that promote signal reliability may provide important insights into the evolution of diverse signalling strategies among species. The signals that animals use to communicate must comprise mechanisms that prohibit or punish dishonesty, and social costs of dishonesty have been demonstrated for several fixed morphological signals (e.g. colour badges of birds and wasps). The costs maintaining the honesty of dynamic signals, which are more flexible and potentially cheatable, are unknown. Using an experimental manipulation of the dynamic visual signals used by male veiled chameleons (Chamaeleo calyptratus) during aggressive interactions, we tested the idea that the honesty of rapid colour change signals is maintained by social costs. Our results reveal that social costs are an important mechanism maintaining the honesty of these dynamic colour signals—‘dishonest’ chameleons whose experimentally manipulated coloration was incongruent with their contest behaviour received more physical aggression than ‘honest’ individuals. This is the first demonstration, to the best our knowledge, that the honesty of a dynamic signal of motivation—physiological colour change—can be maintained by the social costliness of dishonesty. Behavioural responses of signal receivers, irrespective of any specific detection mechanisms, therefore prevent chameleon cheaters from prospering. PMID:27798310

  13. Cognitive cost as dynamic allocation of energetic resources

    PubMed Central

    Christie, S. Thomas; Schrater, Paul

    2015-01-01

    While it is widely recognized that thinking is somehow costly, involving cognitive effort and producing mental fatigue, these costs have alternatively been assumed to exist, treated as the brain's assessment of lost opportunities, or suggested to be metabolic but with implausible biological bases. We present a model of cognitive cost based on the novel idea that the brain senses and plans for longer-term allocation of metabolic resources by purposively conserving brain activity. We identify several distinct ways the brain might control its metabolic output, and show how a control-theoretic model that models decision-making with an energy budget can explain cognitive effort avoidance in terms of an optimal allocation of limited energetic resources. The model accounts for both subject responsiveness to reward and the detrimental effects of hypoglycemia on cognitive function. A critical component of the model is using astrocytic glycogen as a plausible basis for limited energetic reserves. Glycogen acts as an energy buffer that can temporarily support high neural activity beyond the rate supported by blood glucose supply. The published dynamics of glycogen depletion and repletion are consonant with a broad array of phenomena associated with cognitive cost. Our model thus subsumes both the “cost/benefit” and “limited resource” models of cognitive cost while retaining valuable contributions of each. We discuss how the rational control of metabolic resources could underpin the control of attention, working memory, cognitive look ahead, and model-free vs. model-based policy learning. PMID:26379482

  14. Cognitive cost as dynamic allocation of energetic resources.

    PubMed

    Christie, S Thomas; Schrater, Paul

    2015-01-01

    While it is widely recognized that thinking is somehow costly, involving cognitive effort and producing mental fatigue, these costs have alternatively been assumed to exist, treated as the brain's assessment of lost opportunities, or suggested to be metabolic but with implausible biological bases. We present a model of cognitive cost based on the novel idea that the brain senses and plans for longer-term allocation of metabolic resources by purposively conserving brain activity. We identify several distinct ways the brain might control its metabolic output, and show how a control-theoretic model that models decision-making with an energy budget can explain cognitive effort avoidance in terms of an optimal allocation of limited energetic resources. The model accounts for both subject responsiveness to reward and the detrimental effects of hypoglycemia on cognitive function. A critical component of the model is using astrocytic glycogen as a plausible basis for limited energetic reserves. Glycogen acts as an energy buffer that can temporarily support high neural activity beyond the rate supported by blood glucose supply. The published dynamics of glycogen depletion and repletion are consonant with a broad array of phenomena associated with cognitive cost. Our model thus subsumes both the "cost/benefit" and "limited resource" models of cognitive cost while retaining valuable contributions of each. We discuss how the rational control of metabolic resources could underpin the control of attention, working memory, cognitive look ahead, and model-free vs. model-based policy learning.

  15. Counteracting wetland overgrowth increases breeding and staging bird abundances

    NASA Astrophysics Data System (ADS)

    Lehikoinen, Petteri; Lehikoinen, Aleksi; Mikkola-Roos, Markku; Jaatinen, Kim

    2017-01-01

    Human actions have led to loss and degradation of wetlands, impairing their suitability as habitat especially for waterbirds. Such negative effects may be mitigated through habitat management. To date scientific evidence regarding the impacts of these actions remains scarce. We studied guild specific abundances of breeding and staging birds in response to habitat management on 15 Finnish wetlands. In this study management actions comprised several means of vegetation removal to thwart overgrowth. Management cost efficiency was assessed by examining the association between site-specific costs and bird abundances. Several bird guilds exhibited positive connections with both habitat management as well as with invested funds. Most importantly, however, red-listed species and species with special conservation concern as outlined by the EU showed positive correlations with management actions, underlining the conservation value of wetland management. The results suggest that grazing was especially efficient in restoring overgrown wetlands. As a whole this study makes it clear that wetland habitat management constitutes a feasible conservation tool. The marked association between invested funds and bird abundance may prove to be a valuable tool for decision makers when balancing costs and impact of conservation measures against one another.

  16. Quantifying temporal trends in fisheries abundance using Bayesian dynamic linear models: A case study of riverine Smallmouth Bass populations

    USGS Publications Warehouse

    Schall, Megan K.; Blazer, Vicki S.; Lorantas, Robert M.; Smith, Geoffrey; Mullican, John E.; Keplinger, Brandon J.; Wagner, Tyler

    2018-01-01

    Detecting temporal changes in fish abundance is an essential component of fisheries management. Because of the need to understand short‐term and nonlinear changes in fish abundance, traditional linear models may not provide adequate information for management decisions. This study highlights the utility of Bayesian dynamic linear models (DLMs) as a tool for quantifying temporal dynamics in fish abundance. To achieve this goal, we quantified temporal trends of Smallmouth Bass Micropterus dolomieu catch per effort (CPE) from rivers in the mid‐Atlantic states, and we calculated annual probabilities of decline from the posterior distributions of annual rates of change in CPE. We were interested in annual declines because of recent concerns about fish health in portions of the study area. In general, periods of decline were greatest within the Susquehanna River basin, Pennsylvania. The declines in CPE began in the late 1990s—prior to observations of fish health problems—and began to stabilize toward the end of the time series (2011). In contrast, many of the other rivers investigated did not have the same magnitude or duration of decline in CPE. Bayesian DLMs provide information about annual changes in abundance that can inform management and are easily communicated with managers and stakeholders.

  17. Controlling Healthcare Costs: Just Cost Effectiveness or "Just" Cost Effectiveness?

    PubMed

    Fleck, Leonard M

    2018-04-01

    Meeting healthcare needs is a matter of social justice. Healthcare needs are virtually limitless; however, resources, such as money, for meeting those needs, are limited. How then should we (just and caring citizens and policymakers in such a society) decide which needs must be met as a matter of justice with those limited resources? One reasonable response would be that we should use cost effectiveness as our primary criterion for making those choices. This article argues instead that cost-effectiveness considerations must be constrained by considerations of healthcare justice. The goal of this article will be to provide a preliminary account of how we might distinguish just from unjust or insufficiently just applications of cost-effectiveness analysis to some healthcare rationing problems; specifically, problems related to extraordinarily expensive targeted cancer therapies. Unconstrained compassionate appeals for resources for the medically least well-off cancer patients will be neither just nor cost effective.

  18. Effect of land cover, habitat fragmentation and ant colonies on the distribution and abundance of shrews in southern California

    USGS Publications Warehouse

    Laakkonen, Juha; Fisher, Robert N.; Case, Ted J.

    2001-01-01

    Because effects of habitat fragmentation and anthropogenic disturbance on native animals have been relatively little studied in arid areas and in insectivores, we investigated the roles of different land covers, habitat fragmentation and ant colonies on the distribution and abundance of shrews, Notiosorex crawfordi and Sorex ornatus, in southern California.Notiosorex crawfordi was the numerically dominant species (trap-success rate 0·52) occurring in 21 of the 22 study sites in 85% of the 286 pitfall arrays used in this study.Sorex ornatus was captured in 14 of the sites, in 52% of the arrays with a total trap-success rate of 0·2. Neither of the species was found in one of the sites.The population dynamics of the two shrew species were relatively synchronous during the 4–5-year study; the peak densities usually occurred during the spring. Precipitation had a significant positive effect, and maximum temperature a significant negative effect on the trap-success rate of S. ornatus.Occurrence and abundance of shrews varied significantly between sites and years but the size of the landscape or the study site had no effect on the abundance of shrews. The amount of urban edge had no significant effect on the captures of shrews but increased edge allows invasion of the Argentine ants, which had a highly significant negative impact on the abundance of N. crawfordi.At the trap array level, the percentage of coastal sage scrub flora had a significant positive, and the percentage of other flora had a significant negative effect on the abundance of N. crawfordi. The mean canopy height and the abundance of N. crawfordi had a significant positive effect on the occurrence of S. ornatus.Our study suggests that the loss of native coastal sage scrub flora and increasing presence of Argentine ant colonies may significantly effect the distribution and abundance of N. crawfordi. The very low overall population densities of both shrew species in most study sites make both species

  19. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    PubMed

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  20. Fear in grasslands: the effect of Eurasian kestrels on skylark abundances

    NASA Astrophysics Data System (ADS)

    Martínez-Padilla, Jesús; Fargallo, Juan A.

    2008-05-01

    Predation has received considerable theoretical and empirical support in population regulation. The effect of predators, however, could be achieved in direct (killing) or indirect effects (such as displacement). In this paper, we explored the relationship between Eurasian kestrels Falco tinnunculus and skylarks Alauda arvensis in Mediterranean grasslands. First, we analysed the presence of skylarks in the kestrel diet over 9 years. We also compared a grassland area of experimentally increased kestrel density and a second grassland as control area to evaluate the direct or indirect effect on skylark abundance. We also considered two different habitats, grazed and ungrazed plots. If skylark abundance decreased as the kestrel breeding season progressed in high-density kestrel area compared with the control area, it would suggest a direct effect (predator hypothesis). If skylark abundance remains constant in both areas of contrasting kestrel density, it would suggest that skylarks avoid kestrels (avoidance hypothesis). We found that skylark abundance decreased in the kestrel area from the beginning of kestrel nest-box installation to recent years. The rate of skylark consumption decreased in a 9-year period as kestrel abundance increased, although the total amount skylark consumption did not show a decreasing trend. In addition, skylarks were more abundant in the kestrel-free area than in the kestrel area. Finally, we found that skylark abundance did not change through the kestrel breeding period in relation to grazing. We suggest that an increased breeding density of kestrels during their breeding period may force the skylarks to breed in other areas, which may explain the decline of their abundance.

  1. Costs and cost-effectiveness of periviable care.

    PubMed

    Caughey, Aaron B; Burchfield, David J

    2014-02-01

    With increasing concerns regarding rapidly expanding healthcare costs, cost-effectiveness analysis allows assessment of whether marginal gains from new technology are worth the increased costs. Particular methodologic issues related to cost and cost-effectiveness analysis in the area of neonatal and periviable care include how costs are estimated, such as the use of charges and whether long-term costs are included; the challenges of measuring utilities; and whether to use a maternal, neonatal, or dual perspective in such analyses. A number of studies over the past three decades have examined the costs and the cost-effectiveness of neonatal and periviable care. Broadly, while neonatal care is costly, it is also cost effective as it produces both life-years and quality-adjusted life-years (QALYs). However, as the gestational age of the neonate decreases, the costs increase and the cost-effectiveness threshold is harder to achieve. In the periviable range of gestational age (22-24 weeks of gestation), whether the care is cost effective is questionable and is dependent on the perspective. Understanding the methodology and salient issues of cost-effectiveness analysis is critical for researchers, editors, and clinicians to accurately interpret results of the growing body of cost-effectiveness studies related to the care of periviable pregnancies and neonates. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Population dynamics and the ecological stability of obligate pollination mutualisms

    USGS Publications Warehouse

    Holland, J. Nathaniel; DeAngelis, Donald L.

    2001-01-01

    Mutualistic interactions almost always produce both costs and benefits for each of the interacting species. It is the difference between gross benefits and costs that determines the net benefit and the per-capita effect on each of the interacting populations. For example, the net benefit of obligate pollinators, such as yucca and senita moths, to plants is determined by the difference between the number of ovules fertilized from moth pollination and the number of ovules eaten by the pollinator's larvae. It is clear that if pollinator populations are large, then, because many eggs are laid, costs to plants are large, whereas, if pollinator populations are small, gross benefits are low due to lack of pollination. Even though the size and dynamics of the pollinator population are likely to be crucial, their importance has been neglected in the investigation of mechanisms, such as selective fruit abortion, that can limit costs and increase net benefits. Here, we suggest that both the population size and dynamics of pollinators are important in determining the net benefits to plants, and that fruit abortion can significantly affect these. We develop a model of mutualism between populations of plants and their pollinating seed-predators to explore the ecological consequences of fruit abortion on pollinator population dynamics and the net effect on plants. We demonstrate that the benefit to a plant population is unimodal as a function of pollinator abundance, relative to the abundance of flowers. Both selective abortion of fruit with eggs and random abortion of fruit, without reference to whether they have eggs or not, can limit pollinator population size. This can increase the net benefits to the plant population by limiting the number of eggs laid, if the pollination rate remains high. However, fruit abortion can possibly destabilize the pollinator population, with negative consequences for the plant population.

  3. Multitrophic interactions mediate the effects of climate change on herbivore abundance.

    PubMed

    Robinson, Ayla; Inouye, David W; Ogilvie, Jane E; Mooney, Emily H

    2017-10-01

    Climate change can influence the abundance of insect herbivores through direct and indirect mechanisms. In this study, we evaluated multitrophic drivers of herbivore abundance for an aphid species (Aphis helianthi) in a subalpine food web consisting of a host plant (Ligusticum porteri), mutualist ants and predatory lygus bugs (Lygus spp.). We used a model-selection approach to determine which climate and host plant cues best predict year-to-year variation in insect phenology and abundance observed over 6 years. We complemented this observational study with experiments that determined how elevated temperature interacts with (1) host plant phenology and (2) the ant-aphid mutualism to determine aphid abundance. We found date of snowmelt to be the best predictor of yearly abundance of aphid and lygus bug abundance but the direction of this effect differed. Aphids achieved lower abundances in early snowmelt years likely due to increased abundance of lygus bug predators in these years. Elevating temperature of L. porteri flowering stalks reduced their quality as hosts for aphid populations. However, warming aphid colonies on host plants of similar quality increased population growth rates. Importantly, this effect was apparent even in the absence of ants. While we observed fewer ants tending colonies at elevated temperatures, these colonies also had reduced numbers of lygus bug predators. This suggests that mutualism with ants becomes less significant as temperature increases, which contrasts other ant-hemipteran systems. Our observational and experimental results show the importance of multitrophic species interactions for predicting the effect of climate change on the abundances of herbivores.

  4. Accuracy and cost-effectiveness of dynamic contrast-enhanced CT in the characterisation of solitary pulmonary nodules-the SPUtNIk study.

    PubMed

    Qureshi, N R; Rintoul, R C; Miles, K A; George, S; Harris, S; Madden, J; Cozens, K; Little, L A; Eichhorst, K; Jones, J; Moate, P; McClement, C; Pike, L; Sinclair, D; Wong, W L; Shekhdar, J; Eaton, R; Shah, A; Brindle, L; Peebles, C; Banerjee, A; Dizdarevic, S; Han, S; Poon, F W; Groves, A M; Kurban, L; Frew, A J; Callister, M E; Crosbie, P; Gleeson, F V; Karunasaagarar, K; Kankam, O; Gilbert, F J

    2016-01-01

    Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrast-enhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently. The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) ( 18 FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for 18 FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs. Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals. ISRCTN30784948; Pre-results.

  5. Dynamic nonrobotic telemicroscopy via skype: A cost effective solution to teleconsultation.

    PubMed

    Sirintrapun, Sahussapont J; Cimic, Adela

    2012-01-01

    Skype is a peer to peer software application that has been historically used for voice and video calls, instant messaging, and file transfer over the Internet. Few studies are available using Skype specifically for telepathology. Our aim is to show that dynamic nonrobotic teleconsultation is possible and even effective via means of a standard microscope camera capable of live acquisition, Skype, an established broad band internet connection, and experienced pathologists. Both the consulting "sending" pathologist and consultant "receiving" pathologist are reasonably experienced general surgical pathologists at junior attending level with several years of experience in sign out. Forty-five cases were chosen encompassing a broad range of surgical pathology specimens. The cases were prospectively evaluated with the consultant diagnosis used as a preliminary pathologic impression with the final diagnosis being confirmation. Versions of Skype 5.0 and above were used along with established broadband internet connections, usually between academic medical institutions. Forty of forty-five cases (89%) were essentially concordant. In four of forty-five cases (9%), the consulting impression gave a differential, but favored an entity which did not match the final diagnosis. Only one case (2%) did the consulting impression not match the final diagnosis; a discordant opinion. The image quality via Skype screen sharing option is excellent. Essentially no lag time was seen. We have shown in our small pilot study that Skype is an effective cost-efficient means for teleconsultation, particularly in the setting of entity-related differential diagnoses in surgical pathology and when both the consulting and consultant pathologists are reasonably experienced.

  6. Species abundance distribution and population dynamics in a two-community model of neutral ecology

    NASA Astrophysics Data System (ADS)

    Vallade, M.; Houchmandzadeh, B.

    2006-11-01

    Explicit formulas for the steady-state distribution of species in two interconnected communities of arbitrary sizes are derived in the framework of Hubbell’s neutral model of biodiversity. Migrations of seeds from both communities as well as mutations in both of them are taken into account. These results generalize those previously obtained for the “island-continent” model and they allow an analysis of the influence of the ratio of the sizes of the two communities on the dominance/diversity equilibrium. Exact expressions for species abundance distributions are deduced from a master equation for the joint probability distribution of species in the two communities. Moreover, an approximate self-consistent solution is derived. It corresponds to a generalization of previous results and it proves to be accurate over a broad range of parameters. The dynamical correlations between the abundances of a species in both communities are also discussed.

  7. Can a Costly Intervention Be Cost-effective?

    PubMed Central

    Foster, E. Michael; Jones, Damon

    2009-01-01

    Objectives To examine the cost-effectiveness of the Fast Track intervention, a multi-year, multi-component intervention designed to reduce violence among at-risk children. A previous report documented the favorable effect of intervention on the highest-risk group of ninth-graders diagnosed with conduct disorder, as well as self-reported delinquency. The current report addressed the cost-effectiveness of the intervention for these measures of program impact. Design Costs of the intervention were estimated using program budgets. Incremental cost-effectiveness ratios were computed to determine the cost per unit of improvement in the 3 outcomes measured in the 10th year of the study. Results Examination of the total sample showed that the intervention was not cost-effective at likely levels of policymakers' willingness to pay for the key outcomes. Subsequent analysis of those most at risk, however, showed that the intervention likely was cost-effective given specified willingness-to-pay criteria. Conclusions Results indicate that the intervention is cost-effective for the children at highest risk. From a policy standpoint, this finding is encouraging because such children are likely to generate higher costs for society over their lifetimes. However, substantial barriers to cost-effectiveness remain, such as the ability to effectively identify and recruit such higher-risk children in future implementations. PMID:17088509

  8. Model implementation for dynamic computation of system cost

    NASA Astrophysics Data System (ADS)

    Levri, J.; Vaccari, D.

    The Advanced Life Support (ALS) Program metric is the ratio of the equivalent system mass (ESM) of a mission based on International Space Station (ISS) technology to the ESM of that same mission based on ALS technology. ESM is a mission cost analog that converts the volume, power, cooling and crewtime requirements of a mission into mass units to compute an estimate of the life support system emplacement cost. Traditionally, ESM has been computed statically, using nominal values for system sizing. However, computation of ESM with static, nominal sizing estimates cannot capture the peak sizing requirements driven by system dynamics. In this paper, a dynamic model for a near-term Mars mission is described. The model is implemented in Matlab/Simulink' for the purpose of dynamically computing ESM. This paper provides a general overview of the crew, food, biomass, waste, water and air blocks in the Simulink' model. Dynamic simulations of the life support system track mass flow, volume and crewtime needs, as well as power and cooling requirement profiles. The mission's ESM is computed, based upon simulation responses. Ultimately, computed ESM values for various system architectures will feed into an optimization search (non-derivative) algorithm to predict parameter combinations that result in reduced objective function values.

  9. Density-dependent effects of omnivorous stream crayfish on benthic trophic dynamics

    USGS Publications Warehouse

    Ludlam, J.P.; Banks, B. T.; Magoulick, Daniel D.

    2015-01-01

    Crayfish are abundant and important consumers in aquatic food webs and crayfish invasions have demonstrated strong effects of crayfish on multiple trophic levels. Density may be an important factor determining the role of omnivorous crayfish in benthic communities, especially if density alters the strength of trophic interactions. The effect of crayfish density on a simple benthic food web using ceramic tiles was examined in three treatments (crayfish exclusion cage, cage control (open to crayfish), and exposed ceramic tiles) in mesocosms stocked with 6, 12, or 18 crayfish·m-2. We hypothesized that at low densities crayfish consumption of herbivorous chironomids would increase algal abundance, but at high densities crayfish would reduce both periphyton and invertebrates. In the experiment, periphyton and chironomid abundance increased with declining crayfish biomass on day 30 but not day 15. The magnitude of crayfish effects on day 15 periphyton chlorophyll a abundance increased with crayfish biomass, but crayfish effects on day 30 periphyton chlorophyll a or chironomid biomass did not increase with crayfish biomass. In this experiment there was little evidence for a trophic cascade at low crayfish densities and strong omnivory by crayfish dominated trophic dynamics.

  10. Spatial-Temporal Survey and Occupancy-Abundance Modeling To Predict Bacterial Community Dynamics in the Drinking Water Microbiome

    PubMed Central

    Pinto, Ameet J.; Schroeder, Joanna; Lunn, Mary; Sloan, William

    2014-01-01

    ABSTRACT Bacterial communities migrate continuously from the drinking water treatment plant through the drinking water distribution system and into our built environment. Understanding bacterial dynamics in the distribution system is critical to ensuring that safe drinking water is being supplied to customers. We present a 15-month survey of bacterial community dynamics in the drinking water system of Ann Arbor, MI. By sampling the water leaving the treatment plant and at nine points in the distribution system, we show that the bacterial community spatial dynamics of distance decay and dispersivity conform to the layout of the drinking water distribution system. However, the patterns in spatial dynamics were weaker than those for the temporal trends, which exhibited seasonal cycling correlating with temperature and source water use patterns and also demonstrated reproducibility on an annual time scale. The temporal trends were driven by two seasonal bacterial clusters consisting of multiple taxa with different networks of association within the larger drinking water bacterial community. Finally, we show that the Ann Arbor data set robustly conforms to previously described interspecific occupancy abundance models that link the relative abundance of a taxon to the frequency of its detection. Relying on these insights, we propose a predictive framework for microbial management in drinking water systems. Further, we recommend that long-term microbial observatories that collect high-resolution, spatially distributed, multiyear time series of community composition and environmental variables be established to enable the development and testing of the predictive framework. PMID:24865557

  11. Stronger warming effects on microbial abundances in colder regions

    PubMed Central

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-01-01

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra, and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our findings therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions. PMID:26658882

  12. Properties of six short-period massive binaries: A study of the effects of binarity on surface chemical abundances

    NASA Astrophysics Data System (ADS)

    Martins, F.; Mahy, L.; Hervé, A.

    2017-11-01

    Context. A significant percentage of massive stars are found in multiple systems. The effect of binarity on stellar evolution is poorly constrained. In particular, the role of tides and mass transfer on surface chemical abundances is not constrained observationally. Aims: The aim of this study is to investigate the effect of binarity on the stellar properties and surface abundances of massive binaries. Methods: We performed a spectroscopic analysis of six Galactic massive binaries. We obtained the spectra of individual components via a spectral disentangling method and subsequently analyzed these spectra by means of atmosphere models. The stellar parameters and CNO surface abundances were determined. Results: Most of these six systems are comprised of main-sequence stars. Three systems are detached, two are in contact, and no information is available for the sixth system. For 11 out of the 12 stars studied, the surface abundances are only mildly affected by stellar evolution and mixing. The surface abundances are not different from those of single stars within the uncertainties. The secondary of XZ Cep is strongly chemically enriched. Considering previous determinations of surface abundances in massive binary systems suggests that the effect of tides on chemical mixing is limited, whereas the mass transfer and removal of outer layers of the mass donor leads to the appearance of chemically processed material at the surface, although this is not systematic. The evolutionary masses of the components of our six systems are on average 16.5% higher than the dynamical masses. Some systems seem to have reached synchronization, while others may still be in a transitory phase. Based on observations made with the SOPHIE spectrograph on the 1.93 m telescope at Observatoire de Haute-Provence (OHP, CNRS/AMU), France.

  13. Developing a Low-Cost Force Treadmill via Dynamic Modeling.

    PubMed

    Hong, Chih-Yuan; Guo, Lan-Yuen; Song, Rong; Nagurka, Mark L; Sung, Jia-Li; Yen, Chen-Wen

    2017-01-01

    By incorporating force transducers into treadmills, force platform-instrumented treadmills (commonly called force treadmills) can collect large amounts of gait data and enable the ground reaction force (GRF) to be calculated. However, the high cost of force treadmills has limited their adoption. This paper proposes a low-cost force treadmill system with force sensors installed underneath a standard exercise treadmill. It identifies and compensates for the force transmission dynamics from the actual GRF applied on the treadmill track surface to the force transmitted to the force sensors underneath the treadmill body. This study also proposes a testing procedure to assess the GRF measurement accuracy of force treadmills. Using this procedure in estimating the GRF of "walk-on-the-spot motion," it was found that the total harmonic distortion of the tested force treadmill system was about 1.69%, demonstrating the effectiveness of the approach.

  14. Identifying Cost-Effective Dynamic Policies to Control Epidemics

    PubMed Central

    Yaesoubi, Reza; Cohen, Ted

    2016-01-01

    We describe a mathematical decision model for identifying dynamic health policies for controlling epidemics. These dynamic policies aim to select the best current intervention based on accumulating epidemic data and the availability of resources at each decision point. We propose an algorithm to approximate dynamic policies that optimize the population’s net health benefit, a performance measure which accounts for both health and monetary outcomes. We further illustrate how dynamic policies can be defined and optimized for the control of a novel viral pathogen, where a policy maker must decide (i) when to employ or lift a transmission-reducing intervention (e.g. school closure) and (ii) how to prioritize population members for vaccination when a limited quantity of vaccines first become available. Within the context of this application, we demonstrate that dynamic policies can produce higher net health benefit than more commonly described static policies that specify a pre-determined sequence of interventions to employ throughout epidemics. PMID:27449759

  15. Dynamic nonrobotic telemicroscopy via skype: A cost effective solution to teleconsultation

    PubMed Central

    Sirintrapun, Sahussapont J.; Cimic, Adela

    2012-01-01

    Context: Skype is a peer to peer software application that has been historically used for voice and video calls, instant messaging, and file transfer over the Internet. Few studies are available using Skype specifically for telepathology. Aims: Our aim is to show that dynamic nonrobotic teleconsultation is possible and even effective via means of a standard microscope camera capable of live acquisition, Skype, an established broad band internet connection, and experienced pathologists. Settings and Design: Both the consulting “sending” pathologist and consultant “receiving” pathologist are reasonably experienced general surgical pathologists at junior attending level with several years of experience in sign out. Forty-five cases were chosen encompassing a broad range of surgical pathology specimens. The cases were prospectively evaluated with the consultant diagnosis used as a preliminary pathologic impression with the final diagnosis being confirmation. Materials and Methods: Versions of Skype 5.0 and above were used along with established broadband internet connections, usually between academic medical institutions. Results: Forty of forty-five cases (89%) were essentially concordant. In four of forty-five cases (9%), the consulting impression gave a differential, but favored an entity which did not match the final diagnosis. Only one case (2%) did the consulting impression not match the final diagnosis; a discordant opinion. Conclusions: The image quality via Skype screen sharing option is excellent. Essentially no lag time was seen. We have shown in our small pilot study that Skype is an effective cost-efficient means for teleconsultation, particularly in the setting of entity-related differential diagnoses in surgical pathology and when both the consulting and consultant pathologists are reasonably experienced. PMID:23024887

  16. Dynamics of Viral Abundance and Diversity in a Sphagnum-Dominated Peatland: Temporal Fluctuations Prevail Over Habitat.

    PubMed

    Ballaud, Flore; Dufresne, Alexis; Francez, André-Jean; Colombet, Jonathan; Sime-Ngando, Télesphore; Quaiser, Achim

    2015-01-01

    Viruses impact microbial activity and carbon cycling in various environments, but their diversity and ecological importance in Sphagnum-peatlands are unknown. Abundances of viral particles and prokaryotes were monitored bi-monthly at a fen and a bog at two different layers of the peat surface. Viral particle abundance ranged from 1.7 x 10(6) to 5.6 x 10(8) particles mL(-1), and did not differ between fen and bog but showed seasonal fluctuations. These fluctuations were positively correlated with prokaryote abundance and dissolved organic carbon, and negatively correlated with water-table height and dissolved oxygen. Using shotgun metagenomics we observed a shift in viral diversity between winter/spring and summer/autumn, indicating a seasonal succession of viral communities, mainly driven by weather-related environmental changes. Based on the seasonal asynchrony between viral and microbial diversity, we hypothesize a seasonal shift in the active microbial communities associated with a shift from lysogenic to lytic lifestyles. Our results suggest that temporal variations of environmental conditions rather than current habitat differences control the dynamics of virus-host interactions in Sphagnum-dominated peatlands.

  17. Stronger warming effects on microbial abundances in colder regions

    DOE PAGES

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; ...

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra,more » and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our results therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.« less

  18. Non-additive benefit or cost? Disentangling the indirect effects that occur when plants bearing extrafloral nectaries and honeydew-producing insects share exotic ant mutualists.

    PubMed

    Savage, Amy M; Rudgers, Jennifer A

    2013-06-01

    In complex communities, organisms often form mutualisms with multiple different partners simultaneously. Non-additive effects may emerge among species linked by these positive interactions. Ants commonly participate in mutualisms with both honeydew-producing insects (HPI) and their extrafloral nectary (EFN)-bearing host plants. Consequently, HPI and EFN-bearing plants may experience non-additive benefits or costs when these groups co-occur. The outcomes of these interactions are likely to be influenced by variation in preferences among ants for honeydew vs. nectar. In this study, a test was made for non-additive effects on HPI and EFN-bearing plants resulting from sharing exotic ant guards. Preferences of the dominant exotic ant species for nectar vs. honeydew resources were also examined. Ant access, HPI and nectar availability were manipulated on the EFN-bearing shrub, Morinda citrifolia, and ant and HPI abundances, herbivory and plant growth were assessed. Ant-tending behaviours toward HPI across an experimental gradient of nectar availability were also tracked in order to investigate mechanisms underlying ant responses. The dominant ant species, Anoplolepis gracilipes, differed from less invasive ants in response to multiple mutualists, with reductions in plot-wide abundances when nectar was reduced, but no response to HPI reduction. Conversely, at sites where A. gracilipes was absent or rare, abundances of less invasive ants increased when nectar was reduced, but declined when HPI were reduced. Non-additive benefits were found at sites dominated by A. gracilipes, but only for M. citrifolia plants. Responses of HPI at these sites supported predictions of the non-additive cost model. Interestingly, the opposite non-additive patterns emerged at sites dominated by other ants. It was demonstrated that strong non-additive benefits and costs can both occur when a plant and herbivore share mutualist partners. These findings suggest that broadening the community

  19. Non-additive benefit or cost? Disentangling the indirect effects that occur when plants bearing extrafloral nectaries and honeydew-producing insects share exotic ant mutualists

    PubMed Central

    Savage, Amy M.; Rudgers, Jennifer A.

    2013-01-01

    Background and Aims In complex communities, organisms often form mutualisms with multiple different partners simultaneously. Non-additive effects may emerge among species linked by these positive interactions. Ants commonly participate in mutualisms with both honeydew-producing insects (HPI) and their extrafloral nectary (EFN)-bearing host plants. Consequently, HPI and EFN-bearing plants may experience non-additive benefits or costs when these groups co-occur. The outcomes of these interactions are likely to be influenced by variation in preferences among ants for honeydew vs. nectar. In this study, a test was made for non-additive effects on HPI and EFN-bearing plants resulting from sharing exotic ant guards. Preferences of the dominant exotic ant species for nectar vs. honeydew resources were also examined. Methods Ant access, HPI and nectar availability were manipulated on the EFN-bearing shrub, Morinda citrifolia, and ant and HPI abundances, herbivory and plant growth were assessed. Ant-tending behaviours toward HPI across an experimental gradient of nectar availability were also tracked in order to investigate mechanisms underlying ant responses. Key Results The dominant ant species, Anoplolepis gracilipes, differed from less invasive ants in response to multiple mutualists, with reductions in plot-wide abundances when nectar was reduced, but no response to HPI reduction. Conversely, at sites where A. gracilipes was absent or rare, abundances of less invasive ants increased when nectar was reduced, but declined when HPI were reduced. Non-additive benefits were found at sites dominated by A. gracilipes, but only for M. citrifolia plants. Responses of HPI at these sites supported predictions of the non-additive cost model. Interestingly, the opposite non-additive patterns emerged at sites dominated by other ants. Conclusions It was demonstrated that strong non-additive benefits and costs can both occur when a plant and herbivore share mutualist partners. These

  20. Accuracy and cost-effectiveness of dynamic contrast-enhanced CT in the characterisation of solitary pulmonary nodules—the SPUtNIk study

    PubMed Central

    Qureshi, N R; Rintoul, R C; Miles, K A; George, S; Harris, S; Madden, J; Cozens, K; Little, L A; Eichhorst, K; Jones, J; Moate, P; McClement, C; Pike, L; Sinclair, D; Wong, W L; Shekhdar, J; Eaton, R; Shah, A; Brindle, L; Peebles, C; Banerjee, A; Dizdarevic, S; Han, S; Poon, F W; Groves, A M; Kurban, L; Frew, A J; Callister, M E; Crosbie, P; Gleeson, F V; Karunasaagarar, K; Kankam, O; Gilbert, F J

    2016-01-01

    Introduction Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrast-enhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently. Methods and analysis The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) (18FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for 18FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs. Ethics and dissemination Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals. Trial registration number ISRCTN30784948; Pre-results. PMID:27843550

  1. Dynamic modelling of costs and health consequences of school closure during an influenza pandemic

    PubMed Central

    2012-01-01

    Background The purpose of this article is to evaluate the cost-effectiveness of school closure during a potential influenza pandemic and to examine the trade-off between costs and health benefits for school closure involving different target groups and different closure durations. Methods We developed two models: a dynamic disease model capturing the spread of influenza and an economic model capturing the costs and benefits of school closure. Decisions were based on quality-adjusted life years gained using incremental cost-effectiveness ratios. The disease model is an age-structured SEIR compartmental model based on the population of Oslo. We studied the costs and benefits of school closure by varying the age targets (kindergarten, primary school, secondary school) and closure durations (1–10 weeks), given pandemics with basic reproductive number of 1.5, 2.0 or 2.5. Results The cost-effectiveness of school closure varies depending on the target group, duration and whether indirect costs are considered. Using a case fatality rate (CFR) of 0.1-0.2% and with current cost-effectiveness threshold for Norway, closing secondary school is the only cost-effective strategy, when indirect costs are included. The most cost-effective strategies would be closing secondary schools for 8 weeks if R0=1.5, 6 weeks if R0=2.0, and 4 weeks if R0= 2.5. For severe pandemics with case fatality rates of 1-2%, similar to the Spanish flu, or when indirect costs are disregarded, the optimal strategy is closing kindergarten, primary and secondary school for extended periods of time. For a pandemic with 2009 H1N1 characteristics (mild severity and low transmissibility), closing schools would not be cost-effective, regardless of the age target of school children. Conclusions School closure has moderate impact on the epidemic’s scope, but the resulting disruption to society imposes a potentially great cost in terms of lost productivity from parents’ work absenteeism. PMID:23140513

  2. Dynamic cost shifting in hospitals: evidence from the 1980s and 1990s.

    PubMed

    Clement, J P

    The purpose of this paper is to determine whether dynamic cost shifting occurred among acute care hospitals during the period from the early 1980s to the early 1990s and, if so, whether market factors affected the ability to shift costs. Evidence from this study of California acute care hospitals during three time intervals shows that the hospital did practice dynamic cost shifting, but that their ability to shift costs decreased over time. Surprisingly, hospital competition and HMO penetration did not influence cost shifting. However, increasing HMO penetration (measured as the HMO percentage of hospital discharges) did decrease both net prices and costs for the early part of the study, but later was associated with increases in both.

  3. Temperature drives abundance fluctuations, but spatial dynamics is constrained by landscape configuration: Implications for climate-driven range shift in a butterfly.

    PubMed

    Fourcade, Yoan; Ranius, Thomas; Öckinger, Erik

    2017-10-01

    Prediction of species distributions in an altered climate requires knowledge on how global- and local-scale factors interact to limit their current distributions. Such knowledge can be gained through studies of spatial population dynamics at climatic range margins. Here, using a butterfly (Pyrgus armoricanus) as model species, we first predicted based on species distribution modelling that its climatically suitable habitats currently extend north of its realized range. Projecting the model into scenarios of future climate, we showed that the distribution of climatically suitable habitats may shift northward by an additional 400 km in the future. Second, we used a 13-year monitoring dataset including the majority of all habitat patches at the species northern range margin to assess the synergetic impact of temperature fluctuations and spatial distribution of habitat, microclimatic conditions and habitat quality, on abundance and colonization-extinction dynamics. The fluctuation in abundance between years was almost entirely determined by the variation in temperature during the species larval development. In contrast, colonization and extinction dynamics were better explained by patch area, between-patch connectivity and host plant density. This suggests that the response of the species to future climate change may be limited by future land use and how its host plants respond to climate change. It is, thus, probable that dispersal limitation will prevent P. armoricanus from reaching its potential future distribution. We argue that models of range dynamics should consider the factors influencing metapopulation dynamics, especially at the range edges, and not only broad-scale climate. It includes factors acting at the scale of habitat patches such as habitat quality and microclimate and landscape-scale factors such as the spatial configuration of potentially suitable patches. Knowledge of population dynamics under various environmental conditions, and the

  4. Range-wide effects of breeding- and nonbreeding-season climate on the abundance of a Neotropical migrant songbird.

    PubMed

    Wilson, Scott; LaDeau, Shannon L; Tøttrup, Anders P; Marra, Peter P

    2011-09-01

    Geographic variation in the population dynamics of a species can result from regional variability in climate and how it affects reproduction and survival. Identifying such effects for migratory birds requires the integration of population models with knowledge of migratory connectivity between breeding and nonbreeding areas. We used Bayesian hierarchical models with 26 years of Breeding Bird Survey data (1982-2007) to investigate the impacts of breeding- and nonbreeding-season climate on abundance of American Redstarts (Setophaga ruticilla) across the species range. We focused on 15 populations defined by Bird Conservation Regions, and we included variation across routes and observers as well as temporal trends and climate effects. American Redstart populations that breed in eastern North America showed increased abundance following winters with higher plant productivity in the Caribbean where they are expected to overwinter. In contrast, western breeding populations showed little response to conditions in their expected wintering areas in west Mexico, perhaps reflecting lower migratory connectivity or differential effects of winter rainfall on individuals across the species range. Unlike the case with winter climate, we found few effects of temperature prior to arrival in spring (March-April) or during the nesting period (May-June) on abundance the following year. Eight populations showed significant changes in abundance, with the steepest declines in the Atlantic Northern Forest (-3.4%/yr) and the greatest increases in the Prairie Hardwood Transition (4%/yr). This study emphasizes how the effects of climate on populations of migratory birds are context dependent and can vary depending on geographic location and the period of the annual cycle. Such knowledge is essential for predicting regional variation in how populations of a species might vary in their response to climate change.

  5. Effect of Game Management on Wild Red-Legged Partridge Abundance

    PubMed Central

    Díaz-Fernández, Silvia; Arroyo, Beatriz; Casas, Fabián; Martinez-Haro, Monica; Viñuela, Javier

    2013-01-01

    The reduction of game and fish populations has increased investment in management practices. Hunting and fishing managers use several tools to maximize harvest. Managers need to know the impact their management has on wild populations. This issue is especially important to improve management efficacy and biodiversity conservation. We used questionnaires and field bird surveys in 48 hunting estates to assess whether red-legged partridge Alectoris rufa young/adult ratio and summer abundance were related to the intensity of management (provision of supplementary food and water, predator control and releases of farm-bred partridges), harvest intensity or habitat in Central Spain. We hypothesized that partridge abundance would be higher where management practices were applied more intensively. Variation in young/adult ratio among estates was best explained by habitat, year and some management practices. Density of feeders and water points had a positive relationship with this ratio, while the density of partridges released and magpies controlled were negatively related to it. The variables with greatest relative importance were feeders, releases and year. Variations in post-breeding red-legged partridge abundance among estates were best explained by habitat, year, the same management variables that influenced young/adult ratio, and harvest intensity. Harvest intensity was negatively related to partridge abundance. The other management variables had the same type of relationship with abundance as with young/adult ratio, except magpie control. Variables with greatest relative importance were habitat, feeders, water points, releases and harvest intensity. Our study suggests that management had an overall important effect on post-breeding partridge abundance. However, this effect varied among tools, as some had the desired effect (increase in partridge abundance), whereas others did not or even had a negative relationship (such as release of farm-reared birds) and can be

  6. Effectiveness and Cost of Insecticide-Treated Bed Nets and Indoor Residual Spraying for the Control of Cutaneous Leishmaniasis: A Cluster-Randomized Control Trial in Morocco

    PubMed Central

    Faraj, Chafika; Yukich, Joshua; Adlaoui, El Bachir; Wahabi, Rachid; Mnzava, Abraham Peter; Kaddaf, Mustapha; El Idrissi, Abderrahmane Laamrani; Ameur, Btissam; Kleinschmidt, Immo

    2016-01-01

    Cutaneous leishmaniasis (CL) remains an important public health problem in Morocco. A cluster-randomized trial was conducted with the following three study arms: 1) long-lasting insecticide-treated nets (LLINs) plus standard of care environmental management (SoC-EM), 2) indoor residual spraying (IRS) with α-cypermethrin plus SoC-EM, and 3) SoC-EM alone. Incidence of new CL cases by passive and active case detection, sandfly abundance, and cost and cost-effectiveness was compared between study arms over 5 years. Incidence of CL and sandfly abundance were significantly lower in the IRS arm compared with SoC-EM (CL incidence rate ratio = 0.32, 95% confidence interval [CI] = 0.15–0.69, P = 0.005 and sandfly abundance ratio = 0.39, 95% CI = 0.18–0.85, P = 0.022). Reductions in the LLIN arm of the study were not significant, possibly due to poor compliance. IRS was effective and more cost-effective for the prevention of CL in Morocco. PMID:26811431

  7. Absolute quantification of microbial taxon abundances.

    PubMed

    Props, Ruben; Kerckhof, Frederiek-Maarten; Rubbens, Peter; De Vrieze, Jo; Hernandez Sanabria, Emma; Waegeman, Willem; Monsieurs, Pieter; Hammes, Frederik; Boon, Nico

    2017-02-01

    High-throughput amplicon sequencing has become a well-established approach for microbial community profiling. Correlating shifts in the relative abundances of bacterial taxa with environmental gradients is the goal of many microbiome surveys. As the abundances generated by this technology are semi-quantitative by definition, the observed dynamics may not accurately reflect those of the actual taxon densities. We combined the sequencing approach (16S rRNA gene) with robust single-cell enumeration technologies (flow cytometry) to quantify the absolute taxon abundances. A detailed longitudinal analysis of the absolute abundances resulted in distinct abundance profiles that were less ambiguous and expressed in units that can be directly compared across studies. We further provide evidence that the enrichment of taxa (increase in relative abundance) does not necessarily relate to the outgrowth of taxa (increase in absolute abundance). Our results highlight that both relative and absolute abundances should be considered for a comprehensive biological interpretation of microbiome surveys.

  8. Future costs in cost effectiveness analysis.

    PubMed

    Lee, Robert H

    2008-07-01

    This paper resolves several controversies in CEA. Generalizing [Garber, A.M., Phelps, C.E., 1997. Economic foundations of cost-effectiveness analysis. Journal of Health Economics 16 (1), 1-31], the paper shows accounting for unrelated future costs distorts decision making. After replicating [Meltzer, D., 1997. Accounting for future costs in medical cost-effectiveness analysis. Journal of Health Economics 16 (1), 33-64] quite different conclusion that unrelated future costs should be included in CEA, the paper shows that Meltzer's findings result from modeling the budget constraint as an annuity, which is problematic. The paper also shows that related costs should be included in CEA. This holds for a variety of models, including a health maximization model. CEA should treat costs in the manner recommended by Garber and Phelps.

  9. Cost-effectiveness of treating multidrug-resistant tuberculosis.

    PubMed

    Resch, Stephen C; Salomon, Joshua A; Murray, Megan; Weinstein, Milton C

    2006-07-01

    Despite the existence of effective drug treatments, tuberculosis (TB) causes 2 million deaths annually worldwide. Effective treatment is complicated by multidrug-resistant TB (MDR TB) strains that respond only to second-line drugs. We projected the health benefits and cost-effectiveness of using drug susceptibility testing and second-line drugs in a lower-middle-income setting with high levels of MDR TB. We developed a dynamic state-transition model of TB. In a base case analysis, the model was calibrated to approximate the TB epidemic in Peru, a setting with a smear-positive TB incidence of 120 per 100,000 and 4.5% MDR TB among prevalent cases. Secondary analyses considered other settings. The following strategies were evaluated: first-line drugs administered under directly observed therapy (DOTS), locally standardized second-line drugs for previously treated cases (STR1), locally standardized second-line drugs for previously treated cases with test-confirmed MDR TB (STR2), comprehensive drug susceptibility testing and individualized treatment for previously treated cases (ITR1), and comprehensive drug susceptibility testing and individualized treatment for all cases (ITR2). Outcomes were costs per TB death averted and costs per quality-adjusted life year (QALY) gained. We found that strategies incorporating the use of second-line drug regimens following first-line treatment failure were highly cost-effective compared to strategies using first-line drugs only. In our base case, standardized second-line treatment for confirmed MDR TB cases (STR2) had an incremental cost-effectiveness ratio of 720 dollars per QALY (8,700 dollars per averted death) compared to DOTS. Individualized second-line drug treatment for MDR TB following first-line failure (ITR1) provided more benefit at an incremental cost of 990 dollars per QALY (12,000 dollars per averted death) compared to STR2. A more aggressive version of the individualized treatment strategy (ITR2), in which both new

  10. The effects of coastal development on sponge abundance, diversity, and community composition on Jamaican coral reefs.

    PubMed

    Stubler, Amber D; Duckworth, Alan R; Peterson, Bradley J

    2015-07-15

    Over the past decade, development along the northern coast of Jamaica has accelerated, resulting in elevated levels of sedimentation on adjacent reefs. To understand the effects of this development on sponge community dynamics, we conducted surveys at three locations with varying degrees of adjacent coastal development to quantify species richness, abundance and diversity at two depths (8-10 m and 15-18 m). Sediment accumulation rate, total suspended solids and other water quality parameters were also quantified. The sponge community at the location with the least coastal development and anthropogenic influence was often significantly different from the other two locations, and exhibited higher sponge abundance, richness, and diversity. Sponge community composition and size distribution were statistically different among locations. This study provides correlative evidence that coastal development affects aspects of sponge community ecology, although the precise mechanisms are still unclear. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Costs, effects and cost-effectiveness of breast cancer control in Ghana.

    PubMed

    Zelle, Sten G; Nyarko, Kofi M; Bosu, William K; Aikins, Moses; Niëns, Laurens M; Lauer, Jeremy A; Sepulveda, Cecilia R; Hontelez, Jan A C; Baltussen, Rob

    2012-08-01

    Breast cancer control in Ghana is characterised by low awareness, late-stage treatment and poor survival. In settings with severely constrained health resources, there is a need to spend money wisely. To achieve this and to guide policy makers in their selection of interventions, this study systematically compares costs and effects of breast cancer control interventions in Ghana. We used a mathematical model to estimate costs and health effects of breast cancer interventions in Ghana from the healthcare perspective. Analyses were based on the WHO-CHOICE method, with health effects expressed in disability-adjusted life years (DALYs), costs in 2009 US dollars (US$) and cost-effectiveness ratios (CERs) in US$ per DALY averted. Analyses were based on local demographic, epidemiological and economic data, to the extent these data were available. Biennial screening by clinical breast examination (CBE) of women aged 40-69 years, in combination with treatment of all stages, seems the most cost-effective intervention (costing $1299 per DALY averted). The intervention is also economically attractive according to international standards on cost-effectiveness. Mass media awareness raising (MAR) is the second best option (costing $1364 per DALY averted). Mammography screening of women of aged 40-69 years (costing $12,908 per DALY averted) cannot be considered cost-effective. Both CBE screening and MAR seem economically attractive interventions. Given the uncertainty about the effectiveness of these interventions, only their phased introduction, carefully monitored and evaluated, is warranted. Moreover, their implementation is only meaningful if the capacity of basic cancer diagnostic, referral and treatment and possibly palliative services is simultaneously improved. © 2012 Blackwell Publishing Ltd.

  12. Population dynamics and potential of fisheries stock enhancement: practical theory for assessment and policy analysis.

    PubMed

    Lorenzen, Kai

    2005-01-29

    The population dynamics of fisheries stock enhancement, and its potential for generating benefits over and above those obtainable from optimal exploitation of wild stocks alone are poorly understood and highly controversial. I review pertinent knowledge of fish population biology, and extend the dynamic pool theory of fishing to stock enhancement by unpacking recruitment, incorporating regulation in the recruited stock, and accounting for biological differences between wild and hatchery fish. I then analyse the dynamics of stock enhancement and its potential role in fisheries management, using the candidate stock of North Sea sole as an example and considering economic as well as biological criteria. Enhancement through release of recruits or advanced juveniles is predicted to increase total yield and stock abundance, but reduce abundance of the naturally recruited stock component through compensatory responses or overfishing. Economic feasibility of enhancement is subject to strong constraints, including trade-offs between the costs of fishing and hatchery releases. Costs of hatchery fish strongly influence optimal policy, which may range from no enhancement at high cost to high levels of stocking and fishing effort at low cost. Release of genetically maladapted fish reduces the effectiveness of enhancement, and is most detrimental overall if fitness of hatchery fish is only moderately compromised. As a temporary measure for the rebuilding of depleted stocks, enhancement cannot substitute for effort limitation, and is advantageous as an auxiliary measure only if the population has been reduced to a very low proportion of its unexploited biomass. Quantitative analysis of population dynamics is central to the responsible use of stock enhancement in fisheries management, and the necessary tools are available.

  13. Cascading top-down effects of changing oceanic predator abundances.

    PubMed

    Baum, Julia K; Worm, Boris

    2009-07-01

    1. Top-down control can be an important determinant of ecosystem structure and function, but in oceanic ecosystems, where cascading effects of predator depletions, recoveries, and invasions could be significant, such effects had rarely been demonstrated until recently. 2. Here we synthesize the evidence for oceanic top-down control that has emerged over the last decade, focusing on large, high trophic-level predators inhabiting continental shelves, seas, and the open ocean. 3. In these ecosystems, where controlled manipulations are largely infeasible, 'pseudo-experimental' analyses of predator-prey interactions that treat independent predator populations as 'replicates', and temporal or spatial contrasts in predator populations and climate as 'treatments', are increasingly employed to help disentangle predator effects from environmental variation and noise. 4. Substantial reductions in marine mammals, sharks, and piscivorous fishes have led to mesopredator and invertebrate predator increases. Conversely, abundant oceanic predators have suppressed prey abundances. Predation has also inhibited recovery of depleted species, sometimes through predator-prey role reversals. Trophic cascades have been initiated by oceanic predators linking to neritic food webs, but seem inconsistent in the pelagic realm with effects often attenuating at plankton. 5. Top-down control is not uniformly strong in the ocean, and appears contingent on the intensity and nature of perturbations to predator abundances. Predator diversity may dampen cascading effects except where nonselective fisheries deplete entire predator functional groups. In other cases, simultaneous exploitation of predator and prey can inhibit prey responses. Explicit consideration of anthropogenic modifications to oceanic foodwebs should help inform predictions about trophic control. 6. Synthesis and applications. Oceanic top-down control can have important socio-economic, conservation, and management implications as

  14. A systematic review of the cost and cost-effectiveness of electronic discharge communications

    PubMed Central

    Sevick, Laura K; Esmail, Rosmin; Tang, Karen; Lorenzetti, Diane L; Ronksley, Paul; James, Matthew; Santana, Maria; Ghali, William A; Clement, Fiona

    2017-01-01

    Background The transition between acute care and community care can be a vulnerable period in a patients’ treatment due to the potential for postdischarge adverse events. The vulnerability of this period has been attributed to factors related to the miscommunication between hospital-based and community-based physicians. Electronic discharge communication has been proposed as one solution to bridge this communication gap. Prior to widespread implementation of these tools, the costs and benefits should be considered. Objective To establish the cost and cost-effectiveness of electronic discharge communications compared with traditional discharge systems for individuals who have completed care with one provider and are transitioning care to a new provider. Methods We conducted a systematic review of the published literature, using best practices, to identify economic evaluations/cost analyses of electronic discharge communication tools. Inclusion criteria were: (1) economic analysis and (2) electronic discharge communication tool as the intervention. Quality of each article was assessed, and data were summarised using a component-based analysis. Results One thousand unique abstracts were identified, and 57 full-text articles were assessed for eligibility. Four studies met final inclusion criteria. These studies varied in their primary objectives, methodology, costs reported and outcomes. All of the studies were of low to good quality. Three of the studies reported a cost-effectiveness measure ranging from an incremental daily cost of decreasing average discharge note completion by 1 day of $0.331 (2003 Canadian), a cost per page per discharge letter of €9.51 and a dynamic net present value of €31.1 million for a 5-year implementation of the intervention. None of the identified studies considered clinically meaningful patient or quality outcomes. Discussion Economic analyses of electronic discharge communications are scarcely reported, and with inconsistent

  15. A systematic review of the cost and cost-effectiveness of electronic discharge communications.

    PubMed

    Sevick, Laura K; Esmail, Rosmin; Tang, Karen; Lorenzetti, Diane L; Ronksley, Paul; James, Matthew; Santana, Maria; Ghali, William A; Clement, Fiona

    2017-07-02

    The transition between acute care and community care can be a vulnerable period in a patients' treatment due to the potential for postdischarge adverse events. The vulnerability of this period has been attributed to factors related to the miscommunication between hospital-based and community-based physicians. Electronic discharge communication has been proposed as one solution to bridge this communication gap. Prior to widespread implementation of these tools, the costs and benefits should be considered. To establish the cost and cost-effectiveness of electronic discharge communications compared with traditional discharge systems for individuals who have completed care with one provider and are transitioning care to a new provider. We conducted a systematic review of the published literature, using best practices, to identify economic evaluations/cost analyses of electronic discharge communication tools. Inclusion criteria were: (1) economic analysis and (2) electronic discharge communication tool as the intervention. Quality of each article was assessed, and data were summarised using a component-based analysis. One thousand unique abstracts were identified, and 57 full-text articles were assessed for eligibility. Four studies met final inclusion criteria. These studies varied in their primary objectives, methodology, costs reported and outcomes. All of the studies were of low to good quality. Three of the studies reported a cost-effectiveness measure ranging from an incremental daily cost of decreasing average discharge note completion by 1 day of $0.331 (2003 Canadian), a cost per page per discharge letter of €9.51 and a dynamic net present value of €31.1 million for a 5-year implementation of the intervention. None of the identified studies considered clinically meaningful patient or quality outcomes. Economic analyses of electronic discharge communications are scarcely reported, and with inconsistent methodology and outcomes. Further studies are needed

  16. Patterns of rare and abundant marine microbial eukaryotes.

    PubMed

    Logares, Ramiro; Audic, Stéphane; Bass, David; Bittner, Lucie; Boutte, Christophe; Christen, Richard; Claverie, Jean-Michel; Decelle, Johan; Dolan, John R; Dunthorn, Micah; Edvardsen, Bente; Gobet, Angélique; Kooistra, Wiebe H C F; Mahé, Frédéric; Not, Fabrice; Ogata, Hiroyuki; Pawlowski, Jan; Pernice, Massimo C; Romac, Sarah; Shalchian-Tabrizi, Kamran; Simon, Nathalie; Stoeck, Thorsten; Santini, Sébastien; Siano, Raffaele; Wincker, Patrick; Zingone, Adriana; Richards, Thomas A; de Vargas, Colomban; Massana, Ramon

    2014-04-14

    Biological communities are normally composed of a few abundant and many rare species. This pattern is particularly prominent in microbial communities, in which most constituent taxa are usually extremely rare. Although abundant and rare subcommunities may present intrinsic characteristics that could be crucial for understanding community dynamics and ecosystem functioning, microbiologists normally do not differentiate between them. Here, we investigate abundant and rare subcommunities of marine microbial eukaryotes, a crucial group of organisms that remains among the least-explored biodiversity components of the biosphere. We surveyed surface waters of six separate coastal locations in Europe, independently considering the picoplankton, nanoplankton, and microplankton/mesoplankton organismal size fractions. Deep Illumina sequencing of the 18S rRNA indicated that the abundant regional community was mostly structured by organismal size fraction, whereas the rare regional community was mainly structured by geographic origin. However, some abundant and rare taxa presented similar biogeography, pointing to spatiotemporal structure in the rare microeukaryote biosphere. Abundant and rare subcommunities presented regular proportions across samples, indicating similar species-abundance distributions despite taxonomic compositional variation. Several taxa were abundant in one location and rare in other locations, suggesting large oscillations in abundance. The substantial amount of metabolically active lineages found in the rare biosphere suggests that this subcommunity constitutes a diversity reservoir that can respond rapidly to environmental change. We propose that marine planktonic microeukaryote assemblages incorporate dynamic and metabolically active abundant and rare subcommunities, with contrasting structuring patterns but fairly regular proportions, across space and time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Potential retention effect at fish farms boosts zooplankton abundance

    NASA Astrophysics Data System (ADS)

    Fernandez-Jover, D.; Toledo-Guedes, K.; Valero-Rodríguez, J. M.; Fernandez-Gonzalez, V.; Sanchez-Jerez, P.

    2016-11-01

    Coastal aquaculture activities influence wild macrofauna in natural environments due to the introduction of artificial structures, such as floating cages, that provide structural complexity in the pelagic system. This alters the abundance and distribution of the affected species and also their feeding behaviour and diet. Despite this, the effects of coastal aquaculture on zooplankton assemblages and the potential changes in their abundance and distribution remain largely unstudied. Traditional plankton sampling hauls between the farm mooring systems entail some practical difficulties. As an alternative, light traps were deployed at 2 farms in the SW Mediterranean during a whole warm season. Total zooplankton capture by traps at farms was higher than at control locations on every sampling night. It ranged from 3 to 10 times higher for the taxonomic groups: bivalvia, cladocera, cumacea, fish early-life-stages, gastropoda, polychaeta and tanaidacea; 10-20 times higher for amphipoda, chaetognatha, isopoda, mysidacea and ostracoda, and 22 times higher for copepoda and the crustacean juvenile stages zoea and megalopa. Permutational analysis showed significant differences for the most abundant zooplankton groups (copepoda, crustacean larvae, chaetognatha, cladocera, mysidacea and polychaeta). This marked incremental increase in zooplankton taxa at farms was consistent, irrespective of the changing environmental variables registered every night. Reasons for the greater abundance of zooplankton at farms are discussed, although results suggest a retention effect caused by cage structures rather than active attraction through physical or chemical cues.

  18. Methods of cost-effectiveness analysis in the evaluation of new antipsychotics: implications for schizophrenia treatment.

    PubMed

    Neumann, P J

    1999-01-01

    Because health care payers are increasingly interested in learning whether new treatments offer value for money, there has been an abundance of research into the cost-effectiveness of pharmacologic therapies in the United States. In the past few years, a number of studies comparing the cost-effectiveness of the conventional neuroleptics with that of the atypical antipsychotics have been published. Cost-effectiveness analyses show the relationship between the resources used (costs) and the health benefits achieved (effects) for a health or medical intervention compared with an alternative strategy. Ideally, the analyses can help decision makers improve the health of the population by better allocating society's limited health care resources. However, the extent to which cost-effectiveness data are actually used in decision making is unclear. The analyses are sometimes viewed with skepticism, in part because studies differ in their methodological approaches. Recently, the U.S. Panel on Cost-Effectiveness in Health and Medicine offered recommendations for standard methodological practices, which may help improve the quality of studies and the acceptability of the approach in the future. The issue is particularly important in light of new legislation governing how the Food and Drug Administration will regulate promotional claims made by drug companies regarding health economic information.

  19. Effects of conifer release with glyphosate on summer forage abundance for deer in Maine

    USGS Publications Warehouse

    Vreeland, J.K.; Servello, F.A.; Griffith, B.

    1998-01-01

    Effects of conifer release with glyphosate on summer forage availability for large herbivores in northern forests have received relatively little study. We determined effects of glyphosate treatment of clearcuts on abundance of summer foods for white-tailed deer (Odocoileus virginianus) at 1 and 7-10 years posttreatment. We measured the abundance (percent cover in a 0- to 1.8-m height stratum) of five forage classes for deer (leaves of deciduous trees, leaves of deciduous shrubs, forbs, grasses, ferns) on 12 clearcuts (six treated, six untreated) to determine 1-year effects and on 10 clearcuts (five treated, five untreated) to determine 7- to 10-year effects. Abundance of leaves of deciduous trees was greater on untreated sites (38 versus 11%) at 1 year posttreatment, but the difference was less (18 versus 12%) at 7-10 years posttreatment (age x treatment interaction, P = 0.005). Leaves of deciduous shrubs exhibited a similar pattern. Abundance of forbs was similar (13-14%) at 1 year posttreatment but greater on treated sites (29 versus 15%) at 7-10 years posttreatment (P = 0.03). Grasses and ferns were less abundant than other forage classes. Overall, glyphosate application initially decreased the abundance of leaves of deciduous trees and shrubs used as food in summer, but the longer term positive effects on forb abundance may result in little net change in overall habitat value.

  20. How to Appropriately Extrapolate Costs and Utilities in Cost-Effectiveness Analysis.

    PubMed

    Bojke, Laura; Manca, Andrea; Asaria, Miqdad; Mahon, Ronan; Ren, Shijie; Palmer, Stephen

    2017-08-01

    Costs and utilities are key inputs into any cost-effectiveness analysis. Their estimates are typically derived from individual patient-level data collected as part of clinical studies the follow-up duration of which is often too short to allow a robust quantification of the likely costs and benefits a technology will yield over the patient's entire lifetime. In the absence of long-term data, some form of temporal extrapolation-to project short-term evidence over a longer time horizon-is required. Temporal extrapolation inevitably involves assumptions regarding the behaviour of the quantities of interest beyond the time horizon supported by the clinical evidence. Unfortunately, the implications for decisions made on the basis of evidence derived following this practice and the degree of uncertainty surrounding the validity of any assumptions made are often not fully appreciated. The issue is compounded by the absence of methodological guidance concerning the extrapolation of non-time-to-event outcomes such as costs and utilities. This paper considers current approaches to predict long-term costs and utilities, highlights some of the challenges with the existing methods, and provides recommendations for future applications. It finds that, typically, economic evaluation models employ a simplistic approach to temporal extrapolation of costs and utilities. For instance, their parameters (e.g. mean) are typically assumed to be homogeneous with respect to both time and patients' characteristics. Furthermore, costs and utilities have often been modelled to follow the dynamics of the associated time-to-event outcomes. However, cost and utility estimates may be more nuanced, and it is important to ensure extrapolation is carried out appropriately for these parameters.

  1. [Effect of flooding time on community structure and abundance of Geobacteraceae in paddy soil].

    PubMed

    You, Jiaohua; Xia, Shuhong; Wang, Baoli; Qu, Dong

    2011-06-01

    The dynamic characteristics of community structure and relative abundance of Geobacteraceae were investigated to understand their response to microbial iron (III) reducing in flooded paddy soil. The paddy soil was incubated anaerobically and the amount of Fe(II) was determined during the flooding incubation. We retrieved Geobacteraceae sequences from clone libraries constructed for different time points (1 h and day 1, 5, 10, 20 and 30) after flooding of the paddy soil. The diversity and community structure were analyzed by using RFLP method, and the relative abundance of Geobacteraceae was detected by real-time PCR. Microbial reduction of iron (III) changed greatly in early time and was stable after incubated for 20 d in paddy soil. The largest iron reduction potential was 10.16 mg/g with a Vmax of 1.064 mg/(g x d) at the time of 4.84 d whereas this process achieved plateau after 20 days flooding. Diversity of Geobacteraceae, given by alpha indices, fluctuated during the flooding incubation. Two peaks of diversity were observed in treatments of 5 d and 20 d respectively, while significant low diversity appeared in samples of 10 d and 30 d. Beta indices described the differences between community structures of Geobacteraceae and hence reflected the variation of the flooding situation over time. In all samples, 10 RFLP-based preponderant types were found, which fell into clade 1 and clade 2 of Geobacteraceae. The relative abundance of Geobacteraceae was the lowest in 1 d (1.20% ) and the highest in 20 d (4.54%). The dynamic variation of Geobacteraceae diversity, community structure and abundance are closely related to microbial iron (III) reducing in flooding paddy soil.

  2. Cost-effectiveness evaluation of quadrivalent influenza vaccines for seasonal influenza prevention: a dynamic modeling study of Canada and the United Kingdom.

    PubMed

    Thommes, Edward W; Ismaila, Afisi; Chit, Ayman; Meier, Genevieve; Bauch, Christopher T

    2015-10-27

    The adoption of quadrivalent influenza vaccine (QIV) to replace trivalent influenza vaccine (TIV) in immunization programs is growing worldwide, thus helping to address the problem of influenza B lineage mismatch. However, the price per dose of QIV is higher than that of TIV. In such circumstances, cost-effectiveness analyses provide important and relevant information to inform national health recommendations and implementation decisions. This analysis assessed potential vaccine impacts and cost-effectiveness of a country-wide switch from TIV to QIV, in Canada and the UK, from a third-party payer perspective. An age-stratified, dynamic four-strain transmission model which incorporates strain interaction, transmission-rate seasonality and age-specific mixing in the population was used. Model input data were obtained from published literature and online databases. In Canada, we evaluated a switch from TIV to QIV in the entire population. For the UK, we considered two strategies: Children aged 2-17 years who receive the live-attenuated influenza vaccine (LAIV) switch to the quadrivalent formulation (QLAIV), while individuals aged > 18 years switch from TIV to QIV. Two different vaccination uptake scenarios in children (UK1 and UK2, which differ in the vaccine uptake level) were considered. Health and cost outcomes for both vaccination strategies, and the cost-effectiveness of switching from TIV/LAIV to QIV/QLAIV, were estimated from the payer perspective. For Canada and the UK, cost and outcomes were discounted using 5 % and 3.5 % per year, respectively. Overall, in an average influenza season, our model predicts that a nationwide switch from TIV to QIV would prevent 4.6 % influenza cases, 4.9 % general practitioner (GP) visits, 5.7 % each of emergency room (ER) visits and hospitalizations, and 6.8 % deaths in Canada. In the UK (UK1/UK2), implementing QIV would prevent 1.4 %/1.8 % of influenza cases, 1.6 %/2.0 % each of GP and ER visits, 1.5 %/1.9 % of

  3. Model implementation for dynamic computation of system cost for advanced life support

    NASA Technical Reports Server (NTRS)

    Levri, J. A.; Vaccari, D. A.

    2004-01-01

    Life support system designs for long-duration space missions have a multitude of requirements drivers, such as mission objectives, political considerations, cost, crew wellness, inherent mission attributes, as well as many other influences. Evaluation of requirements satisfaction can be difficult, particularly at an early stage of mission design. Because launch cost is a critical factor and relatively easy to quantify, it is a point of focus in early mission design. The method used to determine launch cost influences the accuracy of the estimate. This paper discusses the appropriateness of dynamic mission simulation in estimating the launch cost of a life support system. This paper also provides an abbreviated example of a dynamic simulation life support model and possible ways in which such a model might be utilized for design improvement. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  4. Effects of landscape anthropization on mosquito community composition and abundance

    NASA Astrophysics Data System (ADS)

    Ferraguti, Martina; Martínez-de La Puente, Josué; Roiz, David; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

    2016-07-01

    Anthropogenic landscape transformation has an important effect on vector-borne pathogen transmission. However, the effects of urbanization on mosquito communities are still only poorly known. Here, we evaluate how land-use characteristics are related to the abundance and community composition of mosquitoes in an area with endemic circulation of numerous mosquito-borne pathogens. We collected 340 829 female mosquitoes belonging to 13 species at 45 localities spatially grouped in 15 trios formed by 1 urban, 1 rural and 1 natural area. Mosquito abundance and species richness were greater in natural and rural areas than in urban areas. Environmental factors including land use, vegetation and hydrological characteristics were related to mosquito abundance and community composition. Given the differing competences of each species in pathogen transmission, these results provide valuable information on the transmission potential of mosquito-borne pathogens that will be of great use in public and animal health management by allowing, for instance, the identification of the priority areas for pathogen surveillance and vector control.

  5. Effects of landscape anthropization on mosquito community composition and abundance

    PubMed Central

    Ferraguti, Martina; Martínez-de la Puente, Josué; Roiz, David; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

    2016-01-01

    Anthropogenic landscape transformation has an important effect on vector-borne pathogen transmission. However, the effects of urbanization on mosquito communities are still only poorly known. Here, we evaluate how land-use characteristics are related to the abundance and community composition of mosquitoes in an area with endemic circulation of numerous mosquito-borne pathogens. We collected 340 829 female mosquitoes belonging to 13 species at 45 localities spatially grouped in 15 trios formed by 1 urban, 1 rural and 1 natural area. Mosquito abundance and species richness were greater in natural and rural areas than in urban areas. Environmental factors including land use, vegetation and hydrological characteristics were related to mosquito abundance and community composition. Given the differing competences of each species in pathogen transmission, these results provide valuable information on the transmission potential of mosquito-borne pathogens that will be of great use in public and animal health management by allowing, for instance, the identification of the priority areas for pathogen surveillance and vector control. PMID:27373794

  6. A Low-Cost Data Acquisition System for Automobile Dynamics Applications

    PubMed Central

    González, Alejandro; Vinolas, Jordi

    2018-01-01

    This project addresses the need for the implementation of low-cost acquisition technology in the field of vehicle engineering: the design, development, manufacture, and verification of a low-cost Arduino-based data acquisition platform to be used in <80 Hz data acquisition in vehicle dynamics, using low-cost accelerometers. In addition to this, a comparative study is carried out of professional vibration acquisition technologies and low-cost systems, obtaining optimum results for low- and medium-frequency operations with an error of 2.19% on road tests. It is therefore concluded that these technologies are applicable to the automobile industry, thereby allowing the project costs to be reduced and thus facilitating access to this kind of research that requires limited resources. PMID:29382039

  7. A Low-Cost Data Acquisition System for Automobile Dynamics Applications.

    PubMed

    González, Alejandro; Olazagoitia, José Luis; Vinolas, Jordi

    2018-01-27

    This project addresses the need for the implementation of low-cost acquisition technology in the field of vehicle engineering: the design, development, manufacture, and verification of a low-cost Arduino-based data acquisition platform to be used in <80 Hz data acquisition in vehicle dynamics, using low-cost accelerometers. In addition to this, a comparative study is carried out of professional vibration acquisition technologies and low-cost systems, obtaining optimum results for low- and medium-frequency operations with an error of 2.19% on road tests. It is therefore concluded that these technologies are applicable to the automobile industry, thereby allowing the project costs to be reduced and thus facilitating access to this kind of research that requires limited resources.

  8. General methodology: Costing, budgeting, and techniques for benefit-cost and cost-effectiveness analysis

    NASA Technical Reports Server (NTRS)

    Stretchberry, D. M.; Hein, G. F.

    1972-01-01

    The general concepts of costing, budgeting, and benefit-cost ratio and cost-effectiveness analysis are discussed. The three common methods of costing are presented. Budgeting distributions are discussed. The use of discounting procedures is outlined. The benefit-cost ratio and cost-effectiveness analysis is defined and their current application to NASA planning is pointed out. Specific practices and techniques are discussed, and actual costing and budgeting procedures are outlined. The recommended method of calculating benefit-cost ratios is described. A standardized method of cost-effectiveness analysis and long-range planning are also discussed.

  9. Re-evaluation of the cost-effectiveness and effects of childhood rotavirus vaccination in Norway.

    PubMed

    Hansen Edwards, Christina; de Blasio, Birgitte Freiesleben; Salamanca, Beatriz Valcárcel; Flem, Elmira

    2017-01-01

    Rotavirus vaccination was included into the Norwegian childhood immunisation programme in 2014. Before implementation, rotavirus vaccination was found to be cost-effective from a societal perspective, but not from a healthcare perspective. Since introduction, new data on the incidence and economic effects of rotavirus disease have become available. We assessed early epidemiological effects of the rotavirus vaccination programme and re-evaluated its cost-effectiveness in Norway for the years 2015-2019. Using a dynamic transmission model, we compared the epidemiological effects of the ongoing two-dose vaccination programme with Rotarix®, and a hypothetical 3-dose programme with RotaTeq® with no vaccination. A baseline cost of € 54 per fully vaccinated child was used. Cost-effectiveness was computed from a healthcare and societal perspective, using a decision analytical model. Data on healthcare use and costs, productivity losses and health utilities were based on published and own estimates. Uncertainty was accounted for in one-way, multi-way, and probabilistic sensitivity analyses. During 2015-2019, 114,658 home care cases, 34,571 primary care cases, 7,381 severe cases, and 2 deaths associated with rotavirus disease were avoided due to vaccination. Under baseline assumptions vaccination was cost-effective from a healthcare perspective with a cost per QALY of € 47,447 for Rotarix® and € 52,709 for RotaTeq®. The break-even price was € 70 for Rotarix® and € 67 for RotaTeq®. Vaccination was cost-saving from the societal perspective, and also from a healthcare perspective for vaccine prices below € 25 and € 22 per vaccinated child for Rotarix® and RotaTeq®, respectively. Ongoing childhood rotavirus vaccination in Norway has reduced the rotavirus disease burden substantially, and is cost-effective compared with no vaccination.

  10. Inferring invasive species abundance using removal data from management actions

    USGS Publications Warehouse

    Davis, Amy J.; Hooten, Mevin B.; Miller, Ryan S.; Farnsworth, Matthew L.; Lewis, Jesse S.; Moxcey, Michael; Pepin, Kim M.

    2016-01-01

    Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480–19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small (<50) the effective removal rate needed to accurately estimates abundances was considerably higher (0.70). Based on our post-validation method, 78% of our site/time frame estimates were accurate. To use this modeling framework it is important to have multiple removals (more than three) within a time frame during which demographic changes are minimized (i.e., a closed population; ≤3 months for feral swine). Our results show that the probability of accurately estimating abundance from this model improves with increased sampling effort (8+ flight hours across the 3-month window is best) and increased removal rate. Based on the inverse relationship between inaccurate abundances and

  11. Inferring invasive species abundance using removal data from management actions.

    PubMed

    Davis, Amy J; Hooten, Mevin B; Miller, Ryan S; Farnsworth, Matthew L; Lewis, Jesse; Moxcey, Michael; Pepin, Kim M

    2016-10-01

    Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480-19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small (<50) the effective removal rate needed to accurately estimates abundances was considerably higher (0.70). Based on our post-validation method, 78% of our site/time frame estimates were accurate. To use this modeling framework it is important to have multiple removals (more than three) within a time frame during which demographic changes are minimized (i.e., a closed population; ≤3 months for feral swine). Our results show that the probability of accurately estimating abundance from this model improves with increased sampling effort (8+ flight hours across the 3-month window is best) and increased removal rate. Based on the inverse relationship between inaccurate abundances and

  12. Implications of Abundant Gas and Oil for Climate Forcing

    NASA Astrophysics Data System (ADS)

    Edmonds, J.

    2015-12-01

    Perhaps the most important development in the field of energy over the past decade has been the advent of technologies that enable the production of larger volumes of natural gas and oil at lower cost. The availability of more abundant gas and oil is reshaping the global energy system, with implications for both evolving emissions of CO2 and other climate forcers. More abundant gas and oil will also transform the character of greenhouse gas emissions mitigation. We review recent findings regarding the impact of abundant gas and oil for climate forcing and the challenge of emissions mitigation. We find strong evidence that, absent policies to limits its penetration against renewable energy, abundant gas has little observable impact on CO2 emissions, and tends to increase overall climate forcing, though the latter finding is subject to substantial uncertainty. The presence of abundant gas also affects emissions mitigation. There is relatively little literature exploring the implication of expanded gas availability on the difficulty in meeting emissions mitigation goals. However, preliminary results indicate that on global scales abundant gas does not substantially affect the cost of emissions mitigation, even though natural gas could have an expanded role in emissions mitigation scenarios as compared with scenarios in which natural gas is less abundant.

  13. Mechanisms driving postfire abundance of a generalist mammal

    Treesearch

    R. Zwolak; D. E. Pearson; Y. K. Ortega; E. E. Crone

    2012-01-01

    Changes in vertebrate abundance following disturbance are commonly attributed to shifts in food resources or predation pressure, but underlying mechanisms have rarely been tested. We examined four hypotheses for the commonly reported increase in abundance of deer mouse (Peromyscus maniculatus (Wagner, 1845)) following forest fires: source-sink dynamics, decreased...

  14. Effects of an invasive plant on population dynamics in toads.

    PubMed

    Greenberg, Daniel A; Green, David M

    2013-10-01

    When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline. © 2013 Society for Conservation Biology.

  15. Controls of picophytoplankton abundance and composition in a highly dynamic marine system, the Northern Alboran Sea (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Amorim, Ana L.; León, Pablo; Mercado, Jesús M.; Cortés, Dolores; Gómez, Francisco; Putzeys, Sebastien; Salles, Soluna; Yebra, Lidia

    2016-06-01

    The Alboran Sea is a highly dynamic basin which exhibits a high spatio-temporal variability of hydrographic structures (e.g. fronts, gyres, coastal upwellings). This work compares the abundance and composition of picophytoplankton observed across the northern Alboran Sea among eleven cruises between 2008 and 2012 using flow cytometry. We evaluate the seasonal and longitudinal variability of picophytoplankton on the basis of the circulation regimes at a regional scale and explore the presence of cyanobacteria ecotypes in the basin. The maximal abundances obtained for Prochlorococcus, Synechococcus and picoeukaryotes (12.7 × 104, 13.9 × 104 and 8.6 × 104 cells mL- 1 respectively) were consistent with those reported for other adjacent marine areas. Seasonal changes in the abundance of the three picophytoplankton groups were highly significant although they did not match the patterns described for other coastal waters. Higher abundances of Prochlorococcus were obtained in autumn-winter while Synechococcus and picoeukaryotes exhibited a different seasonal abundance pattern depending on the sector (e.g. Synechococcus showed higher abundance in summer in the west sector and during winter in the eastern study area). Additionally, conspicuous longitudinal gradients were observed for Prochlorococcus and Synechococcus, with Prochlorococcus decreasing from west to east and Synechococcus following the opposite pattern. The analysis of environmental variables (i.e. temperature, salinity and inorganic nutrients) and cell abundances indicates that Prochlorococcus preferred high salinity and nitrate to phosphate ratio. On the contrary, temperature did not seem to play a role in Prochlorococcus distribution as it was numerically important during the whole seasonal cycle. Variability in Synechococcus abundance could not be explained by changes in any environmental variable suggesting that different ecotypes were sampled during the surveys. In particular, our data would indicate

  16. Tangled nature model of evolutionary dynamics reconsidered: Structural and dynamical effects of trait inheritance

    NASA Astrophysics Data System (ADS)

    Andersen, Christian Walther; Sibani, Paolo

    2016-05-01

    Based on the stochastic dynamics of interacting agents which reproduce, mutate, and die, the tangled nature model (TNM) describes key emergent features of biological and cultural ecosystems' evolution. While trait inheritance is not included in many applications, i.e., the interactions of an agent and those of its mutated offspring are taken to be uncorrelated, in the family of TNMs introduced in this work correlations of varying strength are parametrized by a positive integer K . We first show that the interactions generated by our rule are nearly independent of K . Consequently, the structural and dynamical effects of trait inheritance can be studied independently of effects related to the form of the interactions. We then show that changing K strengthens the core structure of the ecology, leads to population abundance distributions better approximated by log-normal probability densities, and increases the probability that a species extant at time tw also survives at t >tw . Finally, survival probabilities of species are shown to decay as powers of the ratio t /tw , a so-called pure aging behavior usually seen in glassy systems of physical origin. We find a quantitative dynamical effect of trait inheritance, namely, that increasing the value of K numerically decreases the decay exponent of the species survival probability.

  17. Tangled nature model of evolutionary dynamics reconsidered: Structural and dynamical effects of trait inheritance.

    PubMed

    Andersen, Christian Walther; Sibani, Paolo

    2016-05-01

    Based on the stochastic dynamics of interacting agents which reproduce, mutate, and die, the tangled nature model (TNM) describes key emergent features of biological and cultural ecosystems' evolution. While trait inheritance is not included in many applications, i.e., the interactions of an agent and those of its mutated offspring are taken to be uncorrelated, in the family of TNMs introduced in this work correlations of varying strength are parametrized by a positive integer K. We first show that the interactions generated by our rule are nearly independent of K. Consequently, the structural and dynamical effects of trait inheritance can be studied independently of effects related to the form of the interactions. We then show that changing K strengthens the core structure of the ecology, leads to population abundance distributions better approximated by log-normal probability densities, and increases the probability that a species extant at time t_{w} also survives at t>t_{w}. Finally, survival probabilities of species are shown to decay as powers of the ratio t/t_{w}, a so-called pure aging behavior usually seen in glassy systems of physical origin. We find a quantitative dynamical effect of trait inheritance, namely, that increasing the value of K numerically decreases the decay exponent of the species survival probability.

  18. Costs and Cost-Effectiveness of Plasmodium vivax Control

    PubMed Central

    White, Michael T.; Yeung, Shunmay; Patouillard, Edith; Cibulskis, Richard

    2016-01-01

    The continued success of efforts to reduce the global malaria burden will require sustained funding for interventions specifically targeting Plasmodium vivax. The optimal use of limited financial resources necessitates cost and cost-effectiveness analyses of strategies for diagnosing and treating P. vivax and vector control tools. Herein, we review the existing published evidence on the costs and cost-effectiveness of interventions for controlling P. vivax, identifying nine studies focused on diagnosis and treatment and seven studies focused on vector control. Although many of the results from the much more extensive P. falciparum literature can be applied to P. vivax, it is not always possible to extrapolate results from P. falciparum–specific cost-effectiveness analyses. Notably, there is a need for additional studies to evaluate the potential cost-effectiveness of radical cure with primaquine for the prevention of P. vivax relapses with glucose-6-phosphate dehydrogenase testing. PMID:28025283

  19. The cost of different types of lameness in dairy cows calculated by dynamic programming.

    PubMed

    Cha, E; Hertl, J A; Bar, D; Gröhn, Y T

    2010-10-01

    Traditionally, studies which placed a monetary value on the effect of lameness have calculated the costs at the herd level and rarely have they been specific to different types of lameness. These costs which have been calculated from former studies are not particularly useful for farmers in making economically optimal decisions depending on individual cow characteristics. The objective of this study was to calculate the cost of different types of lameness at the individual cow level and thereby identify the optimal management decision for each of three representative lameness diagnoses. This model would provide a more informed decision making process in lameness management for maximal economic profitability. We made modifications to an existing dynamic optimization and simulation model, studying the effects of various factors (incidence of lameness, milk loss, pregnancy rate and treatment cost) on the cost of different types of lameness. The average cost per case (US$) of sole ulcer, digital dermatitis and foot rot were 216.07, 132.96 and 120.70, respectively. It was recommended that 97.3% of foot rot cases, 95.5% of digital dermatitis cases and 92.3% of sole ulcer cases be treated. The main contributor to the total cost per case of sole ulcer was milk loss (38%), treatment cost for digital dermatitis (42%) and the effect of decreased fertility for foot rot (50%). This model affords versatility as it allows for parameters such as production costs, economic values and disease frequencies to be altered. Therefore, cost estimates are the direct outcome of the farm specific parameters entered into the model. Thus, this model can provide farmers economically optimal guidelines specific to their individual cows suffering from different types of lameness. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Costs and Cost-Effectiveness of Plasmodium vivax Control.

    PubMed

    White, Michael T; Yeung, Shunmay; Patouillard, Edith; Cibulskis, Richard

    2016-12-28

    The continued success of efforts to reduce the global malaria burden will require sustained funding for interventions specifically targeting Plasmodium vivax The optimal use of limited financial resources necessitates cost and cost-effectiveness analyses of strategies for diagnosing and treating P. vivax and vector control tools. Herein, we review the existing published evidence on the costs and cost-effectiveness of interventions for controlling P. vivax, identifying nine studies focused on diagnosis and treatment and seven studies focused on vector control. Although many of the results from the much more extensive P. falciparum literature can be applied to P. vivax, it is not always possible to extrapolate results from P. falciparum-specific cost-effectiveness analyses. Notably, there is a need for additional studies to evaluate the potential cost-effectiveness of radical cure with primaquine for the prevention of P. vivax relapses with glucose-6-phosphate dehydrogenase testing. © The American Society of Tropical Medicine and Hygiene.

  1. A System Dynamics Approach to Understanding Cost and Revenue Interactions in the Community College Financial System.

    ERIC Educational Resources Information Center

    Howard, James E.

    After identifying the components of a community college financial system as enrollment, costs, revenues and tuition, this paper addresses the need for a system dynamics analysis of a California community college district. This systems approach would assess the possible effects of alternative policies on the characteristic behavior modes of the…

  2. Retrospective cost-effectiveness analyses for polio vaccination in the United States.

    PubMed

    Thompson, Kimberly M; Tebbens, Radboud J Duintjer

    2006-12-01

    The history of polio vaccination in the United States spans 50 years and includes different phases of the disease, multiple vaccines, and a sustained significant commitment of resources. We estimated cost-effectiveness ratios and assessed the net benefits of polio vaccination applicable at various points in time from the societal perspective and we discounted these back to appropriate points in time. We reconstructed vaccine price data from available sources and used these to retrospectively estimate the total costs of the U.S. historical polio vaccination strategies (all costs reported in year 2002 dollars). We estimate that the United States invested approximately US dollars 35 billion (1955 net present value, discount rate of 3%) in polio vaccines between 1955 and 2005 and will invest approximately US dollars 1.4 billion (1955 net present value, or US dollars 6.3 billion in 2006 net present value) between 2006 and 2015 assuming a policy of continued use of inactivated poliovirus vaccine (IPV) for routine vaccination. The historical and future investments translate into over 1.7 billion vaccinations that prevent approximately 1.1 million cases of paralytic polio and over 160,000 deaths (1955 net present values of approximately 480,000 cases and 73,000 deaths). Due to treatment cost savings, the investment implies net benefits of approximately US dollars 180 billion (1955 net present value), even without incorporating the intangible costs of suffering and death and of averted fear. Retrospectively, the U.S. investment in polio vaccination represents a highly valuable, cost-saving public health program. Observed changes in the cost-effectiveness ratio estimates over time suggest the need for living economic models for interventions that appropriately change with time. This article also demonstrates that estimates of cost-effectiveness ratios at any single time point may fail to adequately consider the context of the investment made to date and the importance of

  3. Cost, cost-efficiency and cost-effectiveness of integrated family planning and HIV services.

    PubMed

    Shade, Starley B; Kevany, Sebastian; Onono, Maricianah; Ochieng, George; Steinfeld, Rachel L; Grossman, Daniel; Newmann, Sara J; Blat, Cinthia; Bukusi, Elizabeth A; Cohen, Craig R

    2013-10-01

    To evaluate costs, cost-efficiency and cost-effectiveness of integration of family planning into HIV services. Integration of family planning services into HIV care and treatment clinics. A cluster-randomized trial. Twelve health facilities in Nyanza, Kenya were randomized to integrate family planning into HIV care and treatment; six health facilities were randomized to (nonintegrated) standard-of-care with separately delivered family planning and HIV services. We assessed costs, cost-efficiency (cost per additional use of more effective family planning), and cost-effectiveness (cost per pregnancy averted) associated with the first year of integration of family planning into HIV care. More effective family planning methods included oral and injectable contraceptives, subdermal implants, intrauterine device, and female and male sterilization. We collected cost data through interviews with study staff and review of financial records to determine costs of service integration. Integration of services was associated with an average marginal cost of $841 per site and $48 per female patient. Average overall and marginal costs of integration were associated with personnel costs [initial ($1003 vs. $872) and refresher ($498 vs. $330) training, mentoring ($1175 vs. $902) and supervision ($1694 vs. $1636)], with fewer resources required for other fixed ($18 vs. $0) and recurring expenses ($471 vs. $287). Integration was associated with a marginal cost of $65 for each additional use of more effective family planning and $1368 for each pregnancy averted. Integration of family planning and HIV services is feasible, inexpensive to implement, and cost-efficient in the Kenyan setting, and thus supports current Kenyan integration policy.

  4. Climate change effects on soil microarthropod abundance and community structure

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kardol, Paul; Reynolds, W. Nicholas; Norby, Richard J

    2011-01-01

    Long-term ecosystem responses to climate change strongly depend on how the soil subsystem and its inhabitants respond to these perturbations. Using open-top chambers, we studied the response of soil microarthropods to single and combined effects of ambient and elevated atmospheric [CO{sub 2}], ambient and elevated temperatures and changes in precipitation in constructed old-fields in Tennessee, USA. Microarthropods were assessed five years after treatments were initiated and samples were collected in both November and June. Across treatments, mites and collembola were the most dominant microarthropod groups collected. We did not detect any treatment effects on microarthropod abundance. In November, but notmore » in June, microarthropod richness, however, was affected by the climate change treatments. In November, total microarthropod richness was lower in dry than in wet treatments, and in ambient temperature treatments, richness was higher under elevated [CO{sub 2}] than under ambient [CO{sub 2}]. Differential responses of individual taxa to the climate change treatments resulted in shifts in community composition. In general, the precipitation and warming treatments explained most of the variation in community composition. Across treatments, we found that collembola abundance and richness were positively related to soil moisture content, and that negative relationships between collembola abundance and richness and soil temperature could be explained by temperature-related shifts in soil moisture content. Our data demonstrate how simultaneously acting climate change factors can affect the structure of soil microarthropod communities in old-field ecosystems. Overall, changes in soil moisture content, either as direct effect of changes in precipitation or as indirect effect of warming or elevated [CO{sub 2}], had a larger impact on microarthropod communities than did the direct effects of the warming and elevated [CO{sub 2}] treatments. Moisture-induced shifts in

  5. The effects of environmental factors on daytime sandeel distribution and abundance on the Dogger Bank

    NASA Astrophysics Data System (ADS)

    van der Kooij, Jeroen; Scott, Beth E.; Mackinson, Steven

    2008-10-01

    Spring distribution and abundance of lesser sandeels during the day were linked to zooplankton densities, seabed substrate and various hydrographic factors using small scale empirical data collected in two areas on the Dogger Bank in 2004, 2005 and 2006. The results of a two-step generalized additive model (GAM) suggested that suitable seabed substrate and temperature best explain sandeel distribution (presence/absence) and that sandeel abundance (given presence) was best described by a model that included bottom temperature, difference between surface and bottom temperature and surface salinity. The current study suggests that suitable seabed substrate explains sandeel distribution in the water column. Bottom temperature and surface salinity also played an important role in explaining distribution and abundance, and we speculate that sandeels favour hydrographically dynamic areas. Contrary to our hypothesis sandeels were not strongly associated with areas of high zooplankton density. We speculate that in early spring on the western Dogger Bank plankton is still patchily distributed and that sandeels only emerge from the seabed when feeding conditions near their night-time burrowing habitat are optimal. The results also suggested that when abundance is over a threshold level, the number of sandeel schools increased rather than the schools becoming bigger. This relationship between patchiness and abundance has implications for mortality rates and hence fisheries management.

  6. Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System

    DTIC Science & Technology

    2013-03-01

    scheme. The mechatronics of the maneuver system was provided. The suitability of this design for survival at gun launch was assessed through...Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System by Frank Fresconi, Ilmars Celmins, Mark Ilg, and James...5069 ARL-TR-6363 March 2013 Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System Frank Fresconi, Ilmars

  7. Variations in cost calculations in spine surgery cost-effectiveness research.

    PubMed

    Alvin, Matthew D; Miller, Jacob A; Lubelski, Daniel; Rosenbaum, Benjamin P; Abdullah, Kalil G; Whitmore, Robert G; Benzel, Edward C; Mroz, Thomas E

    2014-06-01

    Cost-effectiveness research in spine surgery has been a prominent focus over the last decade. However, there has yet to be a standardized method developed for calculation of costs in such studies. This lack of a standardized costing methodology may lead to conflicting conclusions on the cost-effectiveness of an intervention for a specific diagnosis. The primary objective of this study was to systematically review all cost-effectiveness studies published on spine surgery and compare and contrast various costing methodologies used. The authors performed a systematic review of the cost-effectiveness literature related to spine surgery. All cost-effectiveness analyses pertaining to spine surgery were identified using the cost-effectiveness analysis registry database of the Tufts Medical Center Institute for Clinical Research and Health Policy, and the MEDLINE database. Each article was reviewed to determine the study subject, methodology, and results. Data were collected from each study, including costs, interventions, cost calculation method, perspective of cost calculation, and definitions of direct and indirect costs if available. Thirty-seven cost-effectiveness studies on spine surgery were included in the present study. Twenty-seven (73%) of the studies involved the lumbar spine and the remaining 10 (27%) involved the cervical spine. Of the 37 studies, 13 (35%) used Medicare reimbursements, 12 (32%) used a case-costing database, 3 (8%) used cost-to-charge ratios (CCRs), 2 (5%) used a combination of Medicare reimbursements and CCRs, 3 (8%) used the United Kingdom National Health Service reimbursement system, 2 (5%) used a Dutch reimbursement system, 1 (3%) used the United Kingdom Department of Health data, and 1 (3%) used the Tricare Military Reimbursement system. Nineteen (51%) studies completed their cost analysis from the societal perspective, 11 (30%) from the hospital perspective, and 7 (19%) from the payer perspective. Of those studies with a societal

  8. Potential cost-effectiveness of supervised injection facilities in Toronto and Ottawa, Canada.

    PubMed

    Enns, Eva A; Zaric, Gregory S; Strike, Carol J; Jairam, Jennifer A; Kolla, Gillian; Bayoumi, Ahmed M

    2016-03-01

    Supervised injection facilities (legally sanctioned spaces for supervised consumption of illicitly obtained drugs) are controversial public health interventions. We determined the optimal number of facilities in two Canadian cities using health economic methods. Dynamic compartmental model of HIV and hepatitis C transmission through sexual contact and sharing of drug use equipment. Toronto and Ottawa, Canada. Simulated population of each city. Zero to five supervised injection facilities. Direct health-care costs and quality-adjusted life-years (QALYs) over 20 years, discounted at 5% per year; incremental cost-effectiveness ratios. In Toronto, one facility cost $4.1 million and resulted in a gain of 385 QALYs over 20 years, for an incremental cost-effectiveness ratio (ICER) of $10,763 per QALY [95% credible interval (95CrI): cost-saving to $278,311]. Establishing one facility in Ottawa had an ICER of $6127 per QALY (95CrI: cost-saving to $179,272). At a $50,000 per QALY threshold, three facilities would be cost-effective in Toronto and two in Ottawa. The probability that establishing three, four, or five facilities in Toronto was cost-effective was 17, 21, and 41%, respectively. Establishing one, two, or three facilities in Ottawa was cost-effective with 13, 35, and 41% probability, respectively. Establishing no facility was unlikely to be the most cost-effective option (14% in Toronto and 10% in Ottawa). In both cities, results were robust if the reduction in needle-sharing among clients of the facilities was at least 50% and fixed operating costs were less than $2.0 million. Using a $50,000 per quality-adjusted life-years threshold for cost-effectiveness, it is likely to be cost-effective to establish at least three legally sanctioned spaces for supervised injection of illicitly obtained drugs in Toronto, Canada and two in Ottawa, Canada. © 2015 Society for the Study of Addiction.

  9. Primer selection impacts specific population abundances but not community dynamics in a monthly time-series 16S rRNA gene amplicon analysis of coastal marine bacterioplankton.

    PubMed

    Wear, Emma K; Wilbanks, Elizabeth G; Nelson, Craig E; Carlson, Craig A

    2018-03-09

    Primers targeting the 16S small subunit ribosomal RNA marker gene, used to characterize bacterial and archaeal communities, have recently been re-evaluated for marine planktonic habitats. To investigate whether primer selection affects the ecological interpretation of bacterioplankton populations and community dynamics, amplicon sequencing with four primer sets targeting several hypervariable regions of the 16S rRNA gene was conducted on both mock communities constructed from cloned 16S rRNA genes and a time-series of DNA samples from the temperate coastal Santa Barbara Channel. Ecological interpretations of community structure (delineation of depth and seasonality, correlations with environmental factors) were similar across primer sets, while population dynamics varied. We observed substantial differences in relative abundances of taxa known to be poorly resolved by some primer sets, such as Thaumarchaeota and SAR11, and unexpected taxa including Roseobacter clades. Though the magnitude of relative abundances of common OTUs differed between primer sets, the relative abundances of the OTUs were nonetheless strongly correlated. We do not endorse one primer set but rather enumerate strengths and weaknesses to facilitate selection appropriate to a system or experimental goal. While 16S rRNA gene primer bias suggests caution in assessing quantitative population dynamics, community dynamics appear robust across studies using different primers. © 2018 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. Longitudinal patterns in flathead catfish relative abundance and length at age within a large river: Effects of an urban gradient

    USGS Publications Warehouse

    Paukert, C.P.; Makinster, A.S.

    2009-01-01

    We investigated the spatial variation of flathead catfish (Pylodictis olivaris) relative abundance and growth in the 274 km long Kansas River to determine if population dynamics of catfish are related to urbanization. Electrofishing was conducted at 462 random sites throughout the river in summer, 2005-2006 to collect fish. Relative abundance of age 1 fish (???200mm), subadult (>200-400mm) and adult fish (>400 mm) ranged from 0.34 to 14.67 fish h-1, mean length at age 1 was 165 (range: 128-195) mm total length (TL) and mean length at age 3 was 376 mm TL (range: 293-419mm TL). The proportion of land use within 200 m of the river edge was between 0 and 0.54 urban. River reaches with high relative abundance of age 1 flathead catfish had high relative abundance of subadult and adult catfish. River reaches with fast flathead catfish growth to age 1 had fast growth to age 3. High urban land use and riprap in the riparian area were evident in river reaches near the heavily populated Kansas City and Topeka, Kansas, USA. Reaches with increased number of log jams and islands had decreased riparian agriculture. Areas of low urbanization had faster flathead catfish growth (r = 0.67, p = 0.005). Relative abundance of flathead catfish was higher in more agricultural areas (r = -0.57, p = 0.02). Changes in land use in riverine environments may alter population dynamics of a fish species within a river. Spatial differences in population dynamics need to be considered when evaluating riverine fish populations. Published in 2008 by John Wiley & Sons Ltd.

  11. Low-cost, efficient wireless intelligent sensors (LEWIS) measuring real-time reference-free dynamic displacements

    NASA Astrophysics Data System (ADS)

    Ozdagli, A. I.; Liu, B.; Moreu, F.

    2018-07-01

    According to railroad managers, displacement of railroad bridges under service loads is an important parameter in the condition assessment and performance evaluation. However, measuring bridge responses in the field is often costly and labor-intensive. This paper proposes a low-cost, efficient wireless intelligent sensor (LEWIS) platform that can compute in real-time the dynamic transverse displacements of railroad bridges under service loads. This sensing platform drives on an open-source Arduino ecosystem and combines low-cost microcontrollers with affordable accelerometers and wireless transmission modules. The proposed LEWIS system is designed to reconstruct dynamic displacements from acceleration measurements onboard, eliminating the need for offline post-processing, and to transmit the data in real-time to a base station where the inspector at the bridge can see the displacements while the train is crossing, or to a remote office if so desired by internet. Researchers validated the effectiveness of the new LEWIS by conducting a series of laboratory experiments. A shake table setup simulated transverse bridge displacements measured on the field and excited the proposed platform, a commercially available wired expensive accelerometer, and reference LVDT displacement sensor. The responses obtained from the wireless system were compared to the displacements reconstructed from commercial accelerometer readings and the reference LVDT. The results of the laboratory experiments demonstrate that the proposed system is capable of reconstructing transverse displacements of railroad bridges under revenue service traffic accurately and transmitting the data in real-time wirelessly. In conclusion, the platform presented in this paper can be used in the performance assessment of railroad bridge network cost-effectively and accurately. Future work includes collecting real-time reference-free displacements of one railroad bridge in Colorado under train crossings to further

  12. Time-driven activity-based costing: A dynamic value assessment model in pediatric appendicitis.

    PubMed

    Yu, Yangyang R; Abbas, Paulette I; Smith, Carolyn M; Carberry, Kathleen E; Ren, Hui; Patel, Binita; Nuchtern, Jed G; Lopez, Monica E

    2017-06-01

    Healthcare reform policies are emphasizing value-based healthcare delivery. We hypothesize that time-driven activity-based costing (TDABC) can be used to appraise healthcare interventions in pediatric appendicitis. Triage-based standing delegation orders, surgical advanced practice providers, and a same-day discharge protocol were implemented to target deficiencies identified in our initial TDABC model. Post-intervention process maps for a hospital episode were created using electronic time stamp data for simple appendicitis cases during February to March 2016. Total personnel and consumable costs were determined using TDABC methodology. The post-intervention TDABC model featured 6 phases of care, 33 processes, and 19 personnel types. Our interventions reduced duration and costs in the emergency department (-41min, -$23) and pre-operative floor (-57min, -$18). While post-anesthesia care unit duration and costs increased (+224min, +$41), the same-day discharge protocol eliminated post-operative floor costs (-$306). Our model incorporating all three interventions reduced total direct costs by 11% ($2753.39 to $2447.68) and duration of hospitalization by 51% (1984min to 966min). Time-driven activity-based costing can dynamically model changes in our healthcare delivery as a result of process improvement interventions. It is an effective tool to continuously assess the impact of these interventions on the value of appendicitis care. II, Type of study: Economic Analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Developing a cost effective rock bed thermal energy storage system: Design and modelling

    NASA Astrophysics Data System (ADS)

    Laubscher, Hendrik Frederik; von Backström, Theodor Willem; Dinter, Frank

    2017-06-01

    Thermal energy storage is an integral part of the drive for low cost of concentrated solar power (CSP). Storage of thermal energy enables CSP plants to provide base load power. Alternative, cheaper concepts for storing thermal energy have been conceptually proposed in previous studies. Using rocks as a storage medium and air as a heat transfer fluid, the proposed concept offers the potential of lower cost storage because of the abundance and affordability of rocks. A packed rock bed thermal energy storage (TES) concept is investigated and a design for an experimental rig is done. This paper describes the design and modelling of an experimental test facility for a cost effective packed rock bed thermal energy storage system. Cost effective, simplified designs for the different subsystems of an experimental setup are developed based on the availability of materials and equipment. Modelling of this design to predict the thermal performance of the TES system is covered in this study. If the concept under consideration proves to be successful, a design that is scalable and commercially viable can be proposed for further development of an industrial thermal energy storage system.

  14. Abundance and distribution of Corallorhiza odontorhiza reflect variations in climate and ectomycorrhizae

    Treesearch

    Melissa K. McCormick; Dennis F. Whigham; John P. O' Neill; Janie J. Becker; Sarah Werner; Hanne N. Rasmussen; Thomas D. Bruns; D. Lee Taylor

    2009-01-01

    The abundance and reproductive activity of orchids have been linked to variations in weather conditions, but few investigators have examined the relationships between orchid flowering dynamics and the distribution and abundance of mycorrhizal fungi. We quantified the abundance of flowering individuals of Corallorhiza odontorhiza, a...

  15. NEON AND OXYGEN ABUNDANCES AND ABUNDANCE RATIO IN THE SOLAR CORONA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Landi, E.; Testa, P., E-mail: elandi@umich.edu

    2015-02-20

    In this work we determine the Ne/O abundance ratio from Solar and Heliospheric Observatory (SOHO)/Solar Ultraviolet Measurement of Emitted Radiation (SUMER) off-disk observations of quiescent streamers over the 1996-2008 period. We find that the Ne/O ratio is approximately constant over solar cycle 23 from 1996 to 2005, at a value of 0.099 ± 0.017; this value is lower than the transition region determinations from the quiet Sun used to infer the neon photospheric abundance from the oxygen photospheric abundance. Also, the Ne/O ratio we determined from SUMER is in excellent agreement with in situ determinations from ACE/SWICS. In 2005-2008, the Ne/O abundancemore » ratio increased with time and reached 0.25 ± 0.05, following the same trend found in the slowest wind analyzed by ACE/SWICS. Further, we measure the absolute abundance in the corona for both oxygen and neon from the data set of 1996 November 22, obtaining A {sub o} = 8.99 ± 0.04 and A {sub Ne} = 7.92 ± 0.03, and we find that both elements are affected by the first ionization potential (FIP) effect, with oxygen being enhanced by a factor of 1.4-2.1 over its photospheric abundance, and neon being changed by a factor of 0.75-1.20. We conclude that the Ne/O ratio is not constant in the solar atmosphere, both in time and at different heights, and that it cannot be reliably used to infer the neon abundance in the photosphere. Also, we argue that the FIP effect was less effective during the minimum of solar cycle 24, and that the Ne/O = 0.25 ± 0.05 value measured at that time is closer to the true photospheric value, leading to a neon photospheric abundance larger than assumed by ≈40%. We discuss the implications of these results for the solar abundance problem, for the FIP effect, and for the identification of the source regions of the solar wind.« less

  16. Wood thrush nest success and post-fledging survival across a temporal pulse of small mammal abundance in an oak forest.

    PubMed

    Schmidt, Kenneth A; Rush, Scott A; Ostfeld, Richard S

    2008-07-01

    1. Synchronized mass production of seed crops, such as acorns, produces a resource pulse that may have far-reaching consequences for songbird populations through its effects on avian predators. Seed production in these forests represents only the first of several pulsed events. Secondary pulses emerge as mast-consuming rodents numerically respond to seed production and tertiary pulses emerge as generalist predators, such as raptors, numerically respond to rodents. In turn, these two groups reduce nest productivity and juvenile survivorship 1 and 2 years, respectively, after the initial pulse in seed production. 2. At our study site in south-eastern New York, USA, autumn acorn abundance (primary pulse) largely determines rodent abundance (secondary pulse) the following spring. We tested the hypotheses that the population dynamics of a shrub-nesting passerine (wood thrush Hylocichla mustelina), is influenced by rodents through the: (a) direct effect of predation by rodents; (b) indirect effect of rodents on the abundance of raptors (tertiary pulse); and (c) indirect effect of rodent abundance on raptor diet. The latter specifically hypothesizes that a crash in the rodent population in the wake of region-wide failure of acorn production leads to an extreme diet shift in raptors that increases post-fledging mortality in birds. 3. We conducted a 3-year study to examine variation in wood thrush nest success and fledgling survival, using radio telemetry, across a pulse of rodent abundance (i.e. low, medium and high). We also updated and reanalysed regional wood thrush population growth rates as a function of the annual variation in rodent abundance. 4. Fledgling survivorship, but not nest success, varied in relation to annual rodent abundance. Raptors and eastern chipmunks Tamias striatus were the most commonly identified predators on fledglings. Fledgling survivorship was greatest at intermediate rodent abundance consistent with a shift in raptor diet. Regional rate of

  17. Mutation dynamics and fitness effects followed in single cells.

    PubMed

    Robert, Lydia; Ollion, Jean; Robert, Jerome; Song, Xiaohu; Matic, Ivan; Elez, Marina

    2018-03-16

    Mutations have been investigated for more than a century but remain difficult to observe directly in single cells, which limits the characterization of their dynamics and fitness effects. By combining microfluidics, time-lapse imaging, and a fluorescent tag of the mismatch repair system in Escherichia coli , we visualized the emergence of mutations in single cells, revealing Poissonian dynamics. Concomitantly, we tracked the growth and life span of single cells, accumulating ~20,000 mutations genome-wide over hundreds of generations. This analysis revealed that 1% of mutations were lethal; nonlethal mutations displayed a heavy-tailed distribution of fitness effects and were dominated by quasi-neutral mutations with an average cost of 0.3%. Our approach has enabled the investigation of single-cell individuality in mutation rate, mutation fitness costs, and mutation interactions. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  18. A Departmental Cost-Effectiveness Model.

    ERIC Educational Resources Information Center

    Holleman, Thomas, Jr.

    In establishing a departmental cost-effectiveness model, the traditional cost-effectiveness model was discussed and equipped with a distant and deflation equation for both benefits and costs. Next, the economics of costing was examined and program costing procedures developed. Then, the model construct was described as it was structured around the…

  19. Modeling species-abundance relationships in multi-species collections

    USGS Publications Warehouse

    Peng, S.; Yin, Z.; Ren, H.; Guo, Q.

    2003-01-01

    Species-abundance relationship is one of the most fundamental aspects of community ecology. Since Motomura first developed the geometric series model to describe the feature of community structure, ecologists have developed many other models to fit the species-abundance data in communities. These models can be classified into empirical and theoretical ones, including (1) statistical models, i.e., negative binomial distribution (and its extension), log-series distribution (and its extension), geometric distribution, lognormal distribution, Poisson-lognormal distribution, (2) niche models, i.e., geometric series, broken stick, overlapping niche, particulate niche, random assortment, dominance pre-emption, dominance decay, random fraction, weighted random fraction, composite niche, Zipf or Zipf-Mandelbrot model, and (3) dynamic models describing community dynamics and restrictive function of environment on community. These models have different characteristics and fit species-abundance data in various communities or collections. Among them, log-series distribution, lognormal distribution, geometric series, and broken stick model have been most widely used.

  20. Affordability and cost-effectiveness: decision-making on the cost-effectiveness plane.

    PubMed

    Sendi, P P; Briggs, A H

    2001-10-01

    Much recent research interest has focused on handling uncertainty in cost-effectiveness analysis and in particular the calculation of confidence intervals for incremental cost-effectiveness ratios (ICERs). Problems of interpretation when ICERs are negative have led to two important and related developments: the use of the net-benefit statistic and the presentation of uncertainty in cost-effectiveness analysis using acceptability curves. However, neither of these developments directly addresses the problem that decision-makers are constrained by a fixed-budget and may not be able to fund new, more expensive interventions, even if they have been shown to represent good value for money. In response to this limitation, the authors introduce the 'affordability curve' which reflects the probability that a programme is affordable for a wide range of threshold budgets. The authors argue that the joint probability an intervention is affordable and cost-effective is more useful for decision-making since it captures both dimensions of the decision problem faced by those responsible for health service budgets. Copyright 2001 John Wiley & Sons, Ltd.

  1. Estimating the spatial scales of landscape effects on abundance

    Treesearch

    Richard Chandler; Jeffrey Hepinstall-Cymerman

    2016-01-01

    Spatial variation in abundance is influenced by local- and landscape-level environmental variables, but modeling landscape effects is challenging because the spatial scales of the relationships are unknown. Current approaches involve buffering survey locations with polygons of various sizes and using model selection to identify the best scale. The buffering...

  2. Biosimilar medicines and cost-effectiveness

    PubMed Central

    Simoens, Steven

    2011-01-01

    Given that biosimilars are agents that are similar but not identical to the reference biopharmaceutical, this study aims to introduce and describe specific issues related to the economic evaluation of biosimilars by focusing on the relative costs, relative effectiveness, and cost-effectiveness of biosimilars. Economic evaluation assesses the cost-effectiveness of a medicine by comparing the costs and outcomes of a medicine with those of a relevant comparator. The assessment of cost-effectiveness of a biosimilar is complicated by the fact that evidence needed to obtain marketing authorization from a registration authority does not always correspond to the data requirements of a reimbursement authority. In particular, this relates to the availability of adequately powered equivalence or noninferiority studies, the need for comparative data about the effectiveness in a real-world setting rather than the efficacy in a structured setting, and the use of health outcome measures instead of surrogate endpoints. As a biosimilar is likely to be less expensive than the comparator (eg, the reference biopharmaceutical), the assessment of the cost-effectiveness of a biosimilar depends on the relative effectiveness. If appropriately designed and powered clinical studies demonstrate equivalent effectiveness between a biosimilar and the comparator, then a cost-minimization analysis identifies the least expensive medicine. If there are differences in the effectiveness of a biosimilar and the comparator, other techniques of economic evaluation need to be employed, such as cost-effectiveness analysis or cost-utility analysis. Given that there may be uncertainty surrounding the long-term safety (ie, risk of immunogenicity and rare adverse events) and effectiveness of a biosimilar, the cost-effectiveness of a biosimilar needs to be calculated at multiple time points throughout the life cycle of the product. PMID:21935330

  3. Seasonal dynamics in community structure, abundance, body size and sex ratio in two species of Neotropical annual fishes.

    PubMed

    Lanés, L E K; Godoy, R S; Maltchik, L; Polačik, M; Blažek, R; Vrtílek, M; Reichard, M

    2016-11-01

    Seven ephemeral pools on the coastal plain of southern Brazil were found to be inhabited by three annual and 22 non-annual fish species. Two common annual species (Austrolebias minuano and Cynopoecilus fulgens) exhibited clear seasonal dynamics, with the appearance of young fishes in the austral autumn (May to June) and a decline in abundance over the seasonal cycle. The third annual species, Austrolebias wolterstorffii, was rare. No seasonal dynamics were observed in non-annual fishes. The relative abundance of non-annual fishes compared with annual fishes increased over the seasonal cycle, but they coexisted widely. The size structure of annual fishes suggested the presence of a single age cohort in most pools though a second age cohort was registered in one pool in August, coinciding with a large flooding. Strong sexual dimorphism in body size was found in C. fulgens throughout the seasonal cycle, while no sexual dimorphism in body size was found in A. minuano. Female-biased sex ratios were recorded in both common annual fish species in the last three sampling dates (in spring), but not during the first two sampling dates (in winter). The natural lifespan of annual fishes was <8 months. Annual fishes disappeared before habitat desiccation in half of the pools, while non-annual fishes were still present. © 2016 The Fisheries Society of the British Isles.

  4. Effect of environment and fallow period on Cosmopolites sordidus population dynamics at the landscape scale.

    PubMed

    Duyck, P-F; Dortel, E; Vinatier, F; Gaujoux, E; Carval, D; Tixier, P

    2012-10-01

    Understanding how the population dynamics of insect pests are affected by environmental factors and agricultural practices is important for pest management. To investigate how the abundance of the banana weevil, Cosmopolites sordidus (Coleoptera: Curculionidae), is related to environmental factors and the length of the fallow period in Martinique, we developed an extensive data set (18,130 observations of weevil abundance obtained with pheromone traps plus associated environmental data) and analysed it with generalized mixed-effects models. At the island scale, C. sordidus abundance was positively related to mean temperature and negatively related to mean rainfall but was not related to soil type. The number of insects trapped was highest during the driest months of the year. Abundance of C. sordidus decreased as the duration of the preceding fallow period increased. The latter finding is inconsistent with the view that fallow-generated decomposing banana tissue is an important resource for larvae that leads to an increase in the pest population. The results are consistent with the view that fallows, in association with pheromone traps, are effective for the control of the banana weevil.

  5. Locally optimal control under unknown dynamics with learnt cost function: application to industrial robot positioning

    NASA Astrophysics Data System (ADS)

    Guérin, Joris; Gibaru, Olivier; Thiery, Stéphane; Nyiri, Eric

    2017-01-01

    Recent methods of Reinforcement Learning have enabled to solve difficult, high dimensional, robotic tasks under unknown dynamics using iterative Linear Quadratic Gaussian control theory. These algorithms are based on building a local time-varying linear model of the dynamics from data gathered through interaction with the environment. In such tasks, the cost function is often expressed directly in terms of the state and control variables so that it can be locally quadratized to run the algorithm. If the cost is expressed in terms of other variables, a model is required to compute the cost function from the variables manipulated. We propose a method to learn the cost function directly from the data, in the same way as for the dynamics. This way, the cost function can be defined in terms of any measurable quantity and thus can be chosen more appropriately for the task to be carried out. With our method, any sensor information can be used to design the cost function. We demonstrate the efficiency of this method through simulating, with the V-REP software, the learning of a Cartesian positioning task on several industrial robots with different characteristics. The robots are controlled in joint space and no model is provided a priori. Our results are compared with another model free technique, consisting in writing the cost function as a state variable.

  6. Abundance and size distribution dynamics of abyssal epibenthic megafauna in the northeast Pacific.

    PubMed

    Ruhl, Henry A

    2007-05-01

    The importance of interannual variation in deep-sea abundances is now becoming recognized. There is, however, relatively little known about what processes dominate the observed fluctuations. The abundance and size distribution of the megabenthos have been examined here using a towed camera system at a deep-sea station in the northeast Pacific (Station M) from 1989 to 2004. This 16-year study included 52 roughly seasonal transects averaging 1.2 km in length with over 35600 photographic frames analyzed. Mobile epibenthic megafauna at 4100 m depth have exhibited interannual scale changes in abundance from one to three orders of magnitude. Increases in abundance have now been significantly linked to decreases in mean body size, suggesting that accruals in abundance probably result from the recruitment of young individuals. Examinations of size-frequency histograms indicate several possible recruitment events. Shifts in size-frequency distributions were also used to make basic estimations of individual growth rates from 1 to 6 mm/month, depending on the taxon. Regional intensification in reproduction followed by recruitment within the study area could explain the majority of observed accruals in abundance. Although some adult migration is certainly probable in accounting for local variation in abundances, the slow movements of benthic life stages restrict regional migrations for most taxa. Negative competitive interactions and survivorship may explain the precipitous declines of some taxa. This and other studies have shown that abundances from protozoans to large benthic invertebrates and fishes all have undergone significant fluctuations in abundance at Station M over periods of weeks to years.

  7. Concentrations of environmental DNA (eDNA) reflect spawning salmon abundance at fine spatial and temporal scales

    USGS Publications Warehouse

    Tillotson, Michael D.; Kelly, Ryan P.; Duda, Jeff; Hoy, Marshal S.; Kralj, James; Quinn, Thomas P.

    2018-01-01

    Developing fast, cost-effective assessments of wild animal abundance is an important goal for many researchers, and environmental DNA (eDNA) holds much promise for this purpose. However, the quantitative relationship between species abundance and the amount of DNA present in the environment is likely to vary substantially among taxa and with ecological context. Here, we report a strong quantitative relationship between eDNA concentration and the abundance of spawning sockeye salmon in a small stream in Alaska, USA, where we took temporally- and spatially-replicated samples during the spawning period. This high-resolution dataset suggests that (1) eDNA concentrations vary significantly day-to-day, and likely within hours, in the context of the dynamic biological event of a salmon spawning season; (2) eDNA, as detected by species-specific quantitative PCR probes, seems to be conserved over short distances (tens of meters) in running water, but degrade quickly over larger scales (ca. 1.5 km); and (3) factors other than the mere presence of live, individual fish — such as location within the stream, live/dead ratio, and water temperature — can affect the eDNA-biomass correlation in space or time. A multivariate model incorporating both biotic and abiotic variables accounted for over 75% of the eDNA variance observed, suggesting that where a system is well-characterized, it may be possible to predict species' abundance from eDNA surveys, although we underscore that species- and system-specific variables are likely to limit the generality of any given quantitative model. Nevertheless, these findings provide an important step toward quantitative applications of eDNA in conservation and management.

  8. Design and development of a cost effective plantar pressure distribution analysis system for the dynamically moving feet.

    PubMed

    Karkokli, R; McConville, K M Valter

    2006-01-01

    This paper portrays the design and instrumentation of a low cost plantar pressure analysis system, suitable for clinical podiatry. The system measures plantar pressure between the foot and shoe during dynamic movement in real-time, which can be used in clinical gait analysis. It contains a pressure sensing insole which the patient can insert in his/her shoe, and user-friendly software to graph and analyze the data. Applications include occupational health and safety, research and private practice.

  9. Impact on total population health and societal cost, and the implication on the actual cost-effectiveness of including tumour necrosis factor-α antagonists in management of ankylosing spondylitis: a dynamic population modelling study.

    PubMed

    Tran-Duy, An; Boonen, Annelies; van de Laar, Mart A F J; Severens, Johan L

    2015-01-01

    Sequential treatment of ankylosing spondylitis (AS) that includes tumour necrosis factor-α antagonists (anti-TNF agents) has been applied in most of the Western countries. Existing cost-effectiveness (CE) models almost exclusively presented the incremental CE of anti-TNF agents using a closed cohort while budget impact studies are mainly lacking. Notwithstanding, information on impact on total population health and societal budget as well as on actual incremental CE for a given decision time span are important for decision makers. This study aimed at quantifying, for different decision time spans starting from January 1, 2014 in the Dutch society, (1) impact of sequential drug treatment strategies without and with inclusion of anti-TNF agents (Strategies 1 and 2, respectively) on total population health and societal cost, and (2) the actual incremental CE of Strategy 2 compared to Strategy 1. Dynamic population modelling was used to capture total population health and cost, and the actual incremental CE. Distinguishing the prevalent AS population on January 1, 2014 and the incident AS cohorts in the subsequent 20 years, the model tracked individually an actual number of AS patients until death or end of the simulation time. During the simulation, data on patient characteristics, history of drug use, costs and health at discrete time points were generated. In Strategy 1, five nonsteroidal anti-inflammatory drugs (NSAIDs) were available but anti-TNF agents withdrawn. In Strategy 2, five NSAIDs and two anti-TNF agents continued to be available. The predicted size of the prevalent AS population in the Dutch society varied within the range of 67,145-69,957 with 44-46 % of the patients receiving anti-TNF agents over the period 2014-2034. The use of anti-TNF agents resulted in an increase in the annual drug costs (168.54-205.28 million Euros), but at the same time caused a decrease in the annual productivity costs (12.58-31.21 million Euros) and in annual costs of

  10. Effects of polycyclic aromatic hydrocarbons on microbial community structure and PAH ring hydroxylating dioxygenase gene abundance in soil.

    PubMed

    Sawulski, Przemyslaw; Clipson, Nicholas; Doyle, Evelyn

    2014-11-01

    Development of successful bioremediation strategies for environments contaminated with recalcitrant pollutants requires in-depth knowledge of the microorganisms and microbial processes involved in degradation. The response of soil microbial communities to three polycyclic aromatic hydrocarbons, phenanthrene (3-ring), fluoranthene (4-ring) and benzo(a)pyrene (5-ring), was examined. Profiles of bacterial, archaeal and fungal communities were generated using molecular fingerprinting techniques (TRFLP, ARISA) and multivariate statistical tools were employed to interpret the effect of PAHs on community dynamics and composition. The extent and rate of PAH removal was directly related to the chemical structure, with the 5-ring PAH benzo(a)pyrene degraded more slowly than phenathrene or fluoranthene. Bacterial, archaeal and fungal communities were all significantly affected by PAH amendment, time and their interaction. Based on analysis of clone libraries, Actinobacteria appeared to dominate in fluoranthene amended soil, although they also represented a significant portion of the diversity in phenanthrene amended and unamended soils. In addition there appeared to be more γ-Proteobacteria and less Bacteroidetes in soil amended with either PAH compared to the control. The soil bacterial community clearly possessed the potential to degrade PAHs as evidenced by the abundance of PAH ring hydroxylating (PAH-RHDα) genes from both gram negative (GN) and gram positive (GP) bacteria in PAH-amended and control soils. Although the dioxygenase gene from GP bacteria was less abundant in soil than the gene associated with GN bacteria, significant (p < 0.001) increases in the abundance of the GP PAH-RHDα gene were observed during phenanthrene and fluoranthene degradation, whereas there was no significant difference in the abundance of the GN PAH-RHDα gene during the course of the experiment. Few studies to-date have examined the effect of pollutants on more than one microbial

  11. [Cost-effectiveness of addiction care].

    PubMed

    Suijkerbuijk, A W M; van Gils, P F; Greeven, P G J; de Wit, G A

    2015-01-01

    A large number of interventions are available for the treatment of addiction. Professionals need to know about the effectiveness and cost-effectiveness of interventions so they can prioritise appropriate interventions for the treatment of addiction. To provide an overview of the scientific literature on the cost-effectiveness of addiction treatment for alcohol- and drug-abusers. We searched the databases Medline and Centre for Reviews and Dissemination. To be relevant for our study, articles had to focus on interventions in the health-care setting, have a Western context and have a health-related outcome measure such as quality adjusted life years (QALY). Twenty-nine studies met our inclusion criteria: 15 for alcohol and 14 for drugs. The studies on alcohol addiction related mainly to brief interventions. They proved to be cost-saving or had a favourable incremental cost-effectiveness ratio (ICER), remaining below the threshold of € 20,000 per QALY. The studies on drug addiction all involved pharmacotherapeutic interventions. In the case of 10 out of 14 interventions, the ICER was less than € 20,000 per QALY. Almost all of the interventions studied were cost-saving or cost-effective. Many studies consider only health-care costs. Additional research, for instance using a social cost-benefit analysis, could provide more details about the costs of addiction and about the impact that an intervention could have in these/the costs.

  12. Cost and cost-effectiveness of nationwide school-based helminth control in Uganda

    PubMed Central

    BROOKER, SIMON; KABATEREINE, NARCIS B; FLEMING, FIONA; DEVLIN, NANCY

    2009-01-01

    Estimates of cost and cost-effectiveness are typically based on a limited number of small-scale studies with no investigation of the existence of economies to scale or intra-country variation in cost and cost-effectiveness. This information gap hinders the efficient allocation of health care resources and the ability to generalize estimates to other settings. The current study investigates the intra-country variation in the cost and cost-effectiveness of nationwide school-based treatment of helminth (worm) infection in Uganda. Programme cost data were collected through semi-structured interviews with districts officials and from accounting records in six of the 23 intervention districts. Both financial and economic costs were assessed. Costs were estimated on the basis of cost in US$ per schoolchild treated and an incremental cost effectiveness ratio (cost in US$ per case of anaemia averted) was used to evaluate programme cost-effectiveness. Sensitivity analysis was performed to assess the effect of discount rate and drug price. The overall economic cost per child treated in the six districts was US$ 0.54 and the cost-effectiveness was US$ 3.19 per case of anaemia averted. Analysis indicated that estimates of both cost and cost-effectiveness differ markedly with the total number of children which received treatment, indicating economies of scale. There was also substantial variation between districts in the cost per individual treated (US$ 0.41-0.91) and cost per anaemia case averted (US$ 1.70-9.51). Independent variables were shown to be statistically associated with both sets of estimates. This study highlights the potential bias in transferring data across settings without understanding the nature of observed variations. PMID:18024966

  13. Putative Effect of Aquifer Recharge on the Abundance and Taxonomic Composition of Endemic Microbial Communities

    PubMed Central

    Sibley, Cally A.; Hutson, John L.; Mitchell, James G.

    2015-01-01

    Drought events and the overexploitation of freshwater resources have led to the increased need to manage groundwater reserves. Aquifer storage and recovery (ASR), whereby artificial water is injected into aquifers for storage, is one of the proposed methods by which freshwater supplies can be increased. Microbial clogging following injection, however, is a major issue. Here, during laboratory simulations of ASR, we used flow cytometry and bar-coded pyrosequencing to investigate changes in microbial abundance and community dynamics. Bacterial abundance ranged from 5.0 × 104 to 1.4 × 107 cells ml-1 before the addition of synthetic wastewater. Following wastewater addition, a 25-fold decrease in abundance was observed, coinciding with a 12-fold increase in viral abundance. Taxa shifted from an overrepresentation of Sphingomonadales, Sphingobacteriales, Rhodospirillales, Caulobacterales, Legionellales, Bacillales, Fusobacteriales and Verrucomicrobiales prior to the addition of synthetic wastewater to Burkholderiales, Actinomycetales, Pseudomonadales, Xanthomonadales, Rhodobacterales, Thizobiales and Thiotrichales following the addition of synthetic wastewater. Furthermore, a significant difference in overall taxonomic composition between the groundwater samples before and after the addition of synthetic wastewater was observed, with water samples exhibiting more similarity to sediment samples after wastewater was added. Collectively, these results suggest that ASR may alter the taxonomic composition of endemic microbial communities and that complete profiles of groundwater properties, including microbial community abundance and composition need to be taken into consideration when selecting aquifers for ASR practices. PMID:26083532

  14. Post-Hurricane Successional Dynamics in Abundance and Diversity of Canopy Arthropods in a Tropical Rainforest.

    PubMed

    Schowalter, T D; Willig, M R; Presley, S J

    2017-02-01

    We quantified long-term successional trajectories of canopy arthropods on six tree species in a tropical rainforest ecosystem in the Luquillo Mountains of Puerto Rico that experienced repeated hurricane-induced disturbances during the 19-yr study (1991-2009). We expected: 1) differential performances of arthropod species to result in taxon- or guild-specific responses; 2) differences in initial conditions to result in distinct successional responses to each hurricane; and 3) the legacy of hurricane-created gaps to persist despite subsequent disturbances. At least one significant effect of gap, time after hurricane, or their interaction occurred for 53 of 116 analyses of taxon abundance, 31 of 84 analyses of guild abundance, and 21 of 60 analyses of biodiversity (e.g., richness, evenness, dominance, and rarity). Significant responses were ∼60% more common for time after hurricane than for gap creation, indicating that temporal changes in habitat during recovery were of primary importance. Both increases and decreases in abundance or diversity occurred in response to each factor. Guild-level responses were probably driven by changes in the abundance of resources on which they rely. For example, detritivores were most abundant soon after hurricanes when litter resources were elevated, whereas sap-suckers were most abundant in gaps where new foliage growth was the greatest. The legacy of canopy gaps created by Hurricane Hugo persisted for at least 19 yr, despite droughts and other hurricanes of various intensities that caused forest damage. This reinforces the need to consider historical legacies when seeking to understand responses to disturbance. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Distribution of Health Effects and Cost-effectiveness of Varicella Vaccination are Shaped by the Impact on Herpes Zoster.

    PubMed

    van Lier, Alies; Lugnér, Anna; Opstelten, Wim; Jochemsen, Petra; Wallinga, Jacco; Schellevis, François; Sanders, Elisabeth; de Melker, Hester; van Boven, Michiel

    2015-10-01

    Varicella zoster virus (VZV) is the etiological agent of varicella and herpes zoster (HZ). It has been hypothesised that immune boosting of latently infected persons by contact with varicella reduces the probability of HZ. If true, universal varicella vaccination may increase HZ incidence due to reduced VZV circulation. To inform decision-making, we conduct cost-effectiveness analyses of varicella vaccination, including effects on HZ. Effects of varicella vaccination are simulated with a dynamic transmission model, parameterised with Dutch VZV seroprevalence and HZ incidence data, and linked to an economic model. We consider vaccination scenarios that differ by whether or not they include immune boosting, and reactivation of vaccine virus. Varicella incidence decreases after introduction of vaccination, while HZ incidence may increase or decrease depending on whether or not immune boosting is present. Without immune boosting, vaccination is expected to be cost-effective or even cost-saving. With immune boosting, vaccination at 95% coverage is not expected to be cost-effective, and may even cause net health losses. Cost-effectiveness of varicella vaccination depends strongly on the impact on HZ and the economic time horizon. Our findings reveal ethical dilemmas as varicella vaccination may result in unequal distribution of health effects between generations.

  16. Separating direct and indirect effects of global change: a population dynamic modeling approach using readily available field data.

    PubMed

    Farrer, Emily C; Ashton, Isabel W; Knape, Jonas; Suding, Katharine N

    2014-04-01

    Two sources of complexity make predicting plant community response to global change particularly challenging. First, realistic global change scenarios involve multiple drivers of environmental change that can interact with one another to produce non-additive effects. Second, in addition to these direct effects, global change drivers can indirectly affect plants by modifying species interactions. In order to tackle both of these challenges, we propose a novel population modeling approach, requiring only measurements of abundance and climate over time. To demonstrate the applicability of this approach, we model population dynamics of eight abundant plant species in a multifactorial global change experiment in alpine tundra where we manipulated nitrogen, precipitation, and temperature over 7 years. We test whether indirect and interactive effects are important to population dynamics and whether explicitly incorporating species interactions can change predictions when models are forecast under future climate change scenarios. For three of the eight species, population dynamics were best explained by direct effect models, for one species neither direct nor indirect effects were important, and for the other four species indirect effects mattered. Overall, global change had negative effects on species population growth, although species responded to different global change drivers, and single-factor effects were slightly more common than interactive direct effects. When the fitted population dynamic models were extrapolated under changing climatic conditions to the end of the century, forecasts of community dynamics and diversity loss were largely similar using direct effect models that do not explicitly incorporate species interactions or best-fit models; however, inclusion of species interactions was important in refining the predictions for two of the species. The modeling approach proposed here is a powerful way of analyzing readily available datasets which should be

  17. Cost-effectiveness of canine vaccination to prevent human rabies in rural Tanzania.

    PubMed

    Fitzpatrick, Meagan C; Hampson, Katie; Cleaveland, Sarah; Mzimbiri, Imam; Lankester, Felix; Lembo, Tiziana; Meyers, Lauren A; Paltiel, A David; Galvani, Alison P

    2014-01-21

    The annual mortality rate of human rabies in rural Africa is 3.6 deaths per 100 000 persons. Rabies can be prevented with prompt postexposure prophylaxis, but this is costly and often inaccessible in rural Africa. Because 99% of human exposures occur through rabid dogs, canine vaccination also prevents transmission of rabies to humans. To evaluate the cost-effectiveness of rabies control through annual canine vaccination campaigns in rural sub-Saharan Africa. We model transmission dynamics in dogs and wildlife and assess empirical uncertainty in the biological variables to make probability-based evaluations of cost-effectiveness. Epidemiologic variables from a contact-tracing study and literature and cost data from ongoing vaccination campaigns. Two districts of rural Tanzania: Ngorongoro and Serengeti. 10 years. Health policymaker. Vaccination coverage ranging from 0% to 95% in increments of 5%. Life-years for health outcomes and 2010 U.S. dollars for economic outcomes. Annual canine vaccination campaigns were very cost-effective in both districts compared with no canine vaccination. In Serengeti, annual campaigns with as much as 70% coverage were cost-saving. Across a wide range of variable assumptions and levels of societal willingness to pay for life-years, the optimal vaccination coverage for Serengeti was 70%. In Ngorongoro, although optimal coverage depended on willingness to pay, vaccination campaigns were always cost-effective and lifesaving and therefore preferred. Canine vaccination was very cost-effective in both districts, but there was greater uncertainty about the optimal coverage in Ngorongoro. Annual canine rabies vaccination campaigns conferred extraordinary value and dramatically reduced the health burden of rabies. National Institutes of Health.

  18. The Interpersonal Sunk-Cost Effect.

    PubMed

    Olivola, Christopher Y

    2018-05-01

    The sunk-cost fallacy-pursuing an inferior alternative merely because we have previously invested significant, but nonrecoverable, resources in it-represents a striking violation of rational decision making. Whereas theoretical accounts and empirical examinations of the sunk-cost effect have generally been based on the assumption that it is a purely intrapersonal phenomenon (i.e., solely driven by one's own past investments), the present research demonstrates that it is also an interpersonal effect (i.e., people will alter their choices in response to other people's past investments). Across eight experiments ( N = 6,076) covering diverse scenarios, I documented sunk-cost effects when the costs are borne by someone other than the decision maker. Moreover, the interpersonal sunk-cost effect is not moderated by social closeness or whether other people observe their sunk costs being "honored." These findings uncover a previously undocumented bias, reveal that the sunk-cost effect is a much broader phenomenon than previously thought, and pose interesting challenges for existing accounts of this fascinating human tendency.

  19. Health economic studies: an introduction to cost-benefit, cost-effectiveness, and cost-utility analyses.

    PubMed

    Angevine, Peter D; Berven, Sigurd

    2014-10-15

    Narrative overview. To provide clinicians with a basic understanding of economic studies, including cost-benefit, cost-effectiveness, and cost-utility analyses. As decisions regarding public health policy, insurance reimbursement, and patient care incorporate factors other than traditional outcomes such as satisfaction or symptom resolution, health economic studies are increasingly prominent in the literature. This trend will likely continue, and it is therefore important for clinicians to have a fundamental understanding of the common types of economic studies and be able to read them critically. In this brief article, the basic concepts of economic studies and the differences between cost-benefit, cost-effectiveness, and cost-utility studies are discussed. An overview of the field of health economic analysis is presented. Cost-benefit, cost-effectiveness, and cost-utility studies all integrate cost and outcome data into a decision analysis model. These different types of studies are distinguished mainly by the way in which outcomes are valued. Obtaining accurate cost data is often difficult and can limit the generalizability of a study. With a basic understanding of health economic analysis, clinicians can be informed consumers of these important studies.

  20. The effect of dams and seasons on malaria incidence and anopheles abundance in Ethiopia

    PubMed Central

    2013-01-01

    Background Reservoirs created by damming rivers are often believed to increase malaria incidence risk and/or stretch the period of malaria transmission. In this paper, we report the effects of a mega hydropower dam on P. falciparum malaria incidence in Ethiopia. Methods A longitudinal cohort study was conducted over a period of 2 years to determine Plasmodium falciparum malaria incidence among children less than 10 years of age living near a mega hydropower dam in Ethiopia. A total of 2080 children from 16 villages located at different distances from a hydropower dam were followed up from 2008 to 2010 using active detection of cases based on weekly house to house visits. Of this cohort of children, 951 (48.09%) were females and 1059 (51.91%) were males, with a median age of 5 years. Malaria vectors were simultaneously surveyed in all the 16 study villages. Frailty models were used to explore associations between time-to-malaria and potential risk factors, whereas, mixed-effects Poisson regression models were used to assess the effect of different covariates on anopheline abundance. Results Overall, 548 (26.86%) children experienced at least one clinical malaria episode during the follow up period with mean incidence rate of 14.26 cases/1000 child-months at risk (95% CI: 12.16 - 16.36). P. falciparum malaria incidence showed no statistically significant association with distance from the dam reservoir (p = 0.32). However, P. falciparum incidence varied significantly between seasons (p < 0.01). The malaria vector, Anopheles arabiensis, was however more abundant in villages nearer to the dam reservoir. Conclusions P. falciparum malaria incidence dynamics were more influenced by seasonal drivers than by the dam reservoir itself. The findings could have implications in timing optimal malaria control interventions and in developing an early warning system in Ethiopia. PMID:23566411

  1. Good research practices for measuring drug costs in cost-effectiveness analyses: a societal perspective: the ISPOR Drug Cost Task Force report--Part II.

    PubMed

    Garrison, Louis P; Mansley, Edward C; Abbott, Thomas A; Bresnahan, Brian W; Hay, Joel W; Smeeding, James

    2010-01-01

    Major guidelines regarding the application of cost-effectiveness analysis (CEA) have recommended the common and widespread use of the "societal perspective" for purposes of consistency and comparability. The objective of this Task Force subgroup report (one of six reports from the International Society for Pharmacoeconomics and Outcomes Research [ISPOR] Task Force on Good Research Practices-Use of Drug Costs for Cost Effectiveness Analysis [Drug Cost Task Force (DCTF)]) was to review the definition of this perspective, assess its specific application in measuring drug costs, identify any limitations in theory or practice, and make recommendations regarding potential improvements. Key articles, books, and reports in the methodological literature were reviewed, summarized, and integrated into a draft review and report. This draft report was posted for review and comment by ISPOR membership. Numerous comments and suggestions were received, and the report was revised in response to them. The societal perspective can be defined by three conditions: 1) the inclusion of time costs, 2) the use of opportunity costs, and 3) the use of community preferences. In practice, very few, if any, published CEAs have met all of these conditions, though many claim to have taken a societal perspective. Branded drug costs have typically used actual acquisition cost rather than the much lower social opportunity costs that would reflect only short-run manufacturing and distribution costs. This practice is understandable, pragmatic, and useful to current decision-makers. Nevertheless, this use of CEA focuses on static rather than dynamic efficacy and overlooks the related incentives for innovation. Our key recommendation is that current CEA practice acknowledge and embrace this limitation by adopting a new standard for the reference case as one of a "limited societal" or "health systems" perspective, using acquisition drug prices while including indirect costs and community preferences. The

  2. Cost-effectiveness of routine varicella vaccination using the measles, mumps, rubella and varicella vaccine in France: an economic analysis based on a dynamic transmission model for varicella and herpes zoster.

    PubMed

    Littlewood, Kavi J; Ouwens, Mario J N M; Sauboin, Christophe; Tehard, Bertrand; Alain, Sophie; Denis, François

    2015-04-01

    Each year in France, varicella and zoster affect large numbers of children and adults, resulting in medical visits, hospitalizations for varicella- and zoster-related complications, and societal costs. Disease prevention by varicella vaccination is feasible, wherein a plausible option involves replacing the combined measles, mumps, and rubella (MMR) vaccine with the combined MMR and varicella (MMRV) vaccine. This study aimed to: (1) assess the cost-effectiveness of adding routine varicella vaccination through MMRV, using different vaccination strategies in France; and (2) address key uncertainties, such as the economic consequences of breakthrough varicella cases, the waning of vaccine-conferred protection, vaccination coverage, and indirect costs. Based on the outputs of a dynamic transmission model that used data on epidemiology and costs from France, a cost-effectiveness model was built. A conservative approach was taken regarding the impact of varicella vaccination on zoster incidence by assuming the validity of the hypothesis of an age-specific boosting of immunity against varicella. The model determined that routine MMRV vaccination is expected to be a cost-effective option, considering a cost-effectiveness threshold of €20,000 per quality-adjusted life-year saved; routine vaccination was cost-saving from the societal perspective. Results were driven by a large decrease in varicella incidence despite a temporary initial increase in the number of zoster cases due to the assumption of exogenous boosting. In the scenario analyses, despite moderate changes in assumptions about incidence and costs, varicella vaccination remained a cost-effective option for France. Routine vaccination with MMRV was associated with high gains in quality-adjusted life-years, substantial reduction in the occurrences of varicella- and zoster-related complications, and few deaths due to varicella. Routine MMRV vaccination is also expected to provide reductions in costs related to

  3. Proprietary hospitals in cost containment.

    PubMed

    Jones, D A

    1985-08-23

    Any effort to control the rise in health care costs must start with analyzing the causes, which are really quite simple. Most cost control efforts fail because they do not address the causes. The causes are large subsidies in several forms that send a false message that health care is free and should be used abundantly, and expansive reimbursement programs that reward inefficient providers with higher payments. This combination of demand stimulation and cost-plus reimbursement produced the world's most expensive health care delivery system and strident calls for reform. A long overdue change in public policy took effect October 1, 1983, when Medicare payments moved from cost-plus reimbursement to fixed, prospectively determined prices. Because it addressed one of the causes of medical inflation, this change has been effective in slowing the rise in Medicare expenditures. Sponsorship of a hospital is not a determinant of its cost-effectiveness. There are examples of efficient and inefficient hospitals in both the voluntary and the investor-owned or taxpaying hospitals. The determining factor is the will of management to keep costs under control.

  4. Modeling habitat and environmental factors affecting mosquito abundance in Chesapeake, Virginia

    NASA Astrophysics Data System (ADS)

    Bellows, Alan Scott

    The models I present in this dissertation were designed to enable mosquito control agencies in the mid-Atlantic region that oversee large jurisdictions to rapidly track the spatial and temporal distributions of mosquito species, especially those species known to be vectors of eastern equine encephalitis and West Nile virus. I was able to keep these models streamlined, user-friendly, and not cost-prohibitive using empirically based digital data to analyze mosquito-abundance patterns in real landscapes. This research is presented in three major chapters: (II) a series of semi-static habitat suitability indices (HSI) grounded on well-documented associations between mosquito abundance and environmental variables, (III) a dynamic model for predicting both spatial and temporal mosquito abundance based on a topographic soil moisture index and recent weather patterns, and (IV) a set of protocols laid out to aid mosquito control agencies for the use of these models. The HSIs (Chapter II) were based on relationships of mosquitoes to digital surrogates of soil moisture and vegetation characteristics. These models grouped mosquitoes species derived from similarities in habitat requirements, life-cycle type, and vector competence. Quantification of relationships was determined using multiple linear regression models. As in Chapter II, relationships between mosquito abundance and environmental factors in Chapter III were quantified using regression models. However, because this model was, in part, a function of changes in weather patterns, it enables the prediction of both 'where' and 'when' mosquito outbreaks are likely to occur. This model is distinctive among similar studies in the literature because of my use of NOAA's NEXRAD Doppler radar (3-hr precipitation accumulation data) to quantify the spatial and temporal distributions in precipitation accumulation. \\ Chapter IV is unique among the chapters in this dissertation because in lieu of presenting new research, it

  5. Public health impact and cost effectiveness of routine childhood vaccination for hepatitis a in Jordan: a dynamic model approach.

    PubMed

    Hayajneh, Wail A; Daniels, Vincent J; James, Cerise K; Kanıbir, Muhammet Nabi; Pilsbury, Matthew; Marks, Morgan; Goveia, Michelle G; Elbasha, Elamin H; Dasbach, Erik; Acosta, Camilo J

    2018-03-07

    As the socioeconomic conditions in Jordan have improved over recent decades the disease and economic burden of Hepatitis A has increased. The purpose of this study is to assess the potential health and economic impact of a two-dose hepatitis A vaccine program covering one-year old children in Jordan. We adapted an age-structured population model of hepatitis A transmission dynamics to project the epidemiologic and economic impact of vaccinating one-year old children for 50 years in Jordan. The epidemiologic model was calibrated using local data on hepatitis A in Jordan. These data included seroprevalence and incidence data from the Jordan Ministry of Health as well as hospitalization data from King Abdullah University Hospital in Irbid, Jordan. We assumed 90% of all children would be vaccinated with the two-dose regimen by two years of age. The economic evaluation adopted a societal perspective and measured benefits using the quality-adjusted life-year (QALY). The modeled vaccination program reduced the incidence of hepatitis A in Jordan by 99%, 50 years after its introduction. The model projected 4.26 million avoided hepatitis A infections, 1.42 million outpatient visits, 22,475 hospitalizations, 508 fulminant cases, 95 liver transplants, and 76 deaths over a 50 year time horizon. In addition, we found, over a 50 year time horizon, the vaccination program would gain 37,502 QALYs and save over $42.6 million in total costs. The vaccination program became cost-saving within 6 years of its introduction and was highly cost-effective during the first 5 years. A vaccination program covering one-year old children is projected to be a cost-saving intervention that will significantly reduce the public health and economic burden of hepatitis A in Jordan.

  6. Cost-effectiveness analysis in markets with high fixed costs.

    PubMed

    Cutler, David M; Ericson, Keith M Marzilli

    2010-01-01

    We consider how to conduct cost-effectiveness analysis when the social cost of a resource differs from the posted price. From the social perspective, the true cost of a medical intervention is the marginal cost of delivering another unit of a treatment, plus the social cost (deadweight loss) of raising the revenue to fund the treatment. We focus on pharmaceutical prices, which have high markups over marginal cost due to the monopoly power granted to pharmaceutical companies when drugs are under patent. We find that the social cost of a branded drug is approximately one-half the market price when the treatment is paid for by a public insurance plan and one-third the market price for mandated coverage by private insurance. We illustrate the importance of correctly accounting for social costs using two examples: coverage for statin drugs and approval for a drug to treat kidney cancer (sorafenib). In each case, we show that the correct social perspective for cost-effectiveness analysis would be more lenient than researcher recommendations.

  7. Costs and cost-effectiveness of pediatric inguinal hernia repair in Uganda.

    PubMed

    Eeson, Gareth; Birabwa-Male, Doreen; Pennington, Mark; Blair, Geoffrey K

    2015-02-01

    Surgically treatable diseases contribute approximately 11% of disability-adjusted life years (DALYs) worldwide yet they remain a neglected public health priority in low- and middle-income countries (LMICs). Pediatric inguinal hernia is the most common congenital abnormality in newborns and a major cause of morbidity and mortality yet elective repair remains largely unavailable in LMICs. This study is aimed to determine the costs and cost-effectiveness of pediatric inguinal hernia repair (PIHR) in a low-resource setting. Medical costs of consecutive elective PIHRs were recorded prospectively at two centers in Uganda. Decision modeling was used to compare two different treatment scenarios (adoption of PIHR and non-adoption) from a provider perspective. A Markov model was constructed to estimate health outcomes under each scenario. The robustness of the cost-effectiveness results in the base case analysis was tested in one-way and probabilistic sensitivity analysis. The primary outcome of interest was cost per DALY averted by the intervention. Sixty-nine PIHRs were performed in 65 children (mean age 3.6 years). Mean cost per procedure was $86.68 US (95% CI 83.1-90.2 USD) and averted an average of 5.7 DALYs each. Incremental cost-effectiveness ratio was $12.41 per DALY averted. The probability of cost-effectiveness was 95% at a cost-effectiveness threshold of $35 per averted DALY. Results were robust to sensitivity analysis under all considered scenarios. Elective PIHR is highly cost-effective for the treatment and prevention of complications of hernia disease even in low-resource settings. PIHR should be prioritized in LMICs alongside other cost-effective interventions.

  8. Can a costly intervention be cost-effective?: An analysis of violence prevention.

    PubMed

    Foster, E Michael; Jones, Damon

    2006-11-01

    To examine the cost-effectiveness of the Fast Track intervention, a multi-year, multi-component intervention designed to reduce violence among at-risk children. A previous report documented the favorable effect of intervention on the highest-risk group of ninth-graders diagnosed with conduct disorder, as well as self-reported delinquency. The current report addressed the cost-effectiveness of the intervention for these measures of program impact. Costs of the intervention were estimated using program budgets. Incremental cost-effectiveness ratios were computed to determine the cost per unit of improvement in the 3 outcomes measured in the 10th year of the study. Examination of the total sample showed that the intervention was not cost-effective at likely levels of policymakers' willingness to pay for the key outcomes. Subsequent analysis of those most at risk, however, showed that the intervention likely was cost-effective given specified willingness-to-pay criteria. Results indicate that the intervention is cost-effective for the children at highest risk. From a policy standpoint, this finding is encouraging because such children are likely to generate higher costs for society over their lifetimes. However, substantial barriers to cost-effectiveness remain, such as the ability to effectively identify and recruit such higher-risk children in future implementations.

  9. Probing surface hydrogen bonding and dynamics by natural abundance, multidimensional, 17O DNP-NMR spectroscopy

    DOE PAGES

    Perras, Frederic A.; Chaudhary, Umesh; Slowing, Igor I.; ...

    2016-05-06

    Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy is increasingly being used as a tool for the atomic-level characterization of surface sites. DNP surface-enhanced SSNMR spectroscopy of materials has, however, been limited to studying relatively receptive nuclei, and the particularly rare 17O nuclide, which is of great interest for materials science, has not been utilized. We demonstrate that advanced 17O SSNMR experiments can be performed on surface species at natural isotopic abundance using DNP. We use 17O DNP surface-enhanced 2D SSNMR to measure 17O{ 1H} HETCOR spectra as well as dipolar oscillations on a series of thermally treatedmore » mesoporous silica nanoparticle samples having different pore diameters. These experiments allow for a nonintrusive and unambiguous characterization of hydrogen bonding and dynamics at the surface of the material; no other single experiment can give such details about the interactions at the surface. Lastly, our data show that, upon drying, strongly hydrogen-bonded surface silanols, whose motions are greatly restricted by the interaction when compared to lone silanols, are selectively dehydroxylated.« less

  10. Effectiveness and Cost-Effectiveness of Antidepressants in Primary Care: A Multiple Treatment Comparison Meta-Analysis and Cost-Effectiveness Model

    PubMed Central

    Ramsberg, Joakim; Asseburg, Christian; Henriksson, Martin

    2012-01-01

    Objective To determine effectiveness and cost-effectiveness over a one-year time horizon of pharmacological first line treatment in primary care for patients with moderate to severe depression. Design A multiple treatment comparison meta-analysis was employed to determine the relative efficacy in terms of remission of 10 antidepressants (citalopram, duloxetine escitalopram, fluoxetine, fluvoxamine mirtazapine, paroxetine, reboxetine, sertraline and venlafaxine). The estimated remission rates were then applied in a decision-analytic model in order to estimate costs and quality of life with different treatments at one year. Data Sources Meta-analyses of remission rates from randomised controlled trials, and cost and quality-of-life data from published sources. Results The most favourable pharmacological treatment in terms of remission was escitalopram with an 8- to 12-week probability of remission of 0.47. Despite a high acquisition cost, this clinical effectiveness translated into escitalopram being both more effective and having a lower total cost than all other comparators from a societal perspective. From a healthcare perspective, the cost per QALY of escitalopram was €3732 compared with venlafaxine. Conclusion Of the investigated antidepressants, escitalopram has the highest probability of remission and is the most effective and cost-effective pharmacological treatment in a primary care setting, when evaluated over a one year time-horizon. Small differences in remission rates may be important when assessing costs and cost-effectiveness of antidepressants. PMID:22876296

  11. Costs and cost-effectiveness of malaria control interventions - a systematic review

    PubMed Central

    2011-01-01

    Background The control and elimination of malaria requires expanded coverage of and access to effective malaria control interventions such as insecticide-treated nets (ITNs), indoor residual spraying (IRS), intermittent preventive treatment (IPT), diagnostic testing and appropriate treatment. Decisions on how to scale up the coverage of these interventions need to be based on evidence of programme effectiveness, equity and cost-effectiveness. Methods A systematic review of the published literature on the costs and cost-effectiveness of malaria interventions was undertaken. All costs and cost-effectiveness ratios were inflated to 2009 USD to allow comparison of the costs and benefits of several different interventions through various delivery channels, across different geographical regions and from varying costing perspectives. Results Fifty-five studies of the costs and forty three studies of the cost-effectiveness of malaria interventions were identified, 78% of which were undertaken in sub-Saharan Africa, 18% in Asia and 4% in South America. The median financial cost of protecting one person for one year was $2.20 (range $0.88-$9.54) for ITNs, $6.70 (range $2.22-$12.85) for IRS, $0.60 (range $0.48-$1.08) for IPT in infants, $4.03 (range $1.25-$11.80) for IPT in children, and $2.06 (range $0.47-$3.36) for IPT in pregnant women. The median financial cost of diagnosing a case of malaria was $4.32 (range $0.34-$9.34). The median financial cost of treating an episode of uncomplicated malaria was $5.84 (range $2.36-$23.65) and the median financial cost of treating an episode of severe malaria was $30.26 (range $15.64-$137.87). Economies of scale were observed in the implementation of ITNs, IRS and IPT, with lower unit costs reported in studies with larger numbers of beneficiaries. From a provider perspective, the median incremental cost effectiveness ratio per disability adjusted life year averted was $27 (range $8.15-$110) for ITNs, $143 (range $135-$150) for IRS, and

  12. Infrastructure features outperform environmental variables explaining rabbit abundance around motorways.

    PubMed

    Planillo, Aimara; Malo, Juan E

    2018-01-01

    Human disturbance is widespread across landscapes in the form of roads that alter wildlife populations. Knowing which road features are responsible for the species response and their relevance in comparison with environmental variables will provide useful information for effective conservation measures. We sampled relative abundance of European rabbits, a very widespread species, in motorway verges at regional scale, in an area with large variability in environmental and infrastructure conditions. Environmental variables included vegetation structure, plant productivity, distance to water sources, and altitude. Infrastructure characteristics were the type of vegetation in verges, verge width, traffic volume, and the presence of embankments. We performed a variance partitioning analysis to determine the relative importance of two sets of variables on rabbit abundance. Additionally, we identified the most important variables and their effects model averaging after model selection by AICc on hypothesis-based models. As a group, infrastructure features explained four times more variability in rabbit abundance than environmental variables, being the effects of the former critical in motorway stretches located in altered landscapes with no available habitat for rabbits, such as agricultural fields. Model selection and Akaike weights showed that verge width and traffic volume are the most important variables explaining rabbit abundance index, with positive and negative effects, respectively. In the light of these results, the response of species to the infrastructure can be modulated through the modification of motorway features, being some of them manageable in the design phase. The identification of such features leads to suggestions for improvement through low-cost corrective measures and conservation plans. As a general indication, keeping motorway verges less than 10 m wide will prevent high densities of rabbits and avoid the unwanted effects that rabbit populations

  13. The invasive ant, Solenopsis invicta, reduces herpetofauna richness and abundance

    USGS Publications Warehouse

    Allen, Craig R.; Birge, Hannah E.; Slater, J.; Wiggers, E.

    2017-01-01

    Amphibians and reptiles are declining globally. One potential cause of this decline includes impacts resulting from co-occurrence with non-native red imported fire ant, Solenopsis invicta. Although a growing body of anecdotal and observational evidence from laboratory experiments supports this hypothesis, there remains a lack of field scale manipulations testing the effect of fire ants on reptile and amphibian communities. We addressed this gap by measuring reptile and amphibian (“herpetofauna”) community response to successful fire ant reductions over the course of 2 years following hydramethylnon application to five 100–200 ha plots in southeastern coastal South Carolina. By assessing changes in relative abundance and species richness of herpetofauna in response to fire ant reductions, we were able to assess whether some species were particularly vulnerable to fire ant presence, and whether this sensitivity manifested at the community level. We found that herpetofauna abundance and species richness responded positively to fire ant reductions. Our results document that even moderate populations of red imported fire ants decrease both the abundance and diversity of herpetofauna. Given global herpetofauna population declines and continued spread of fire ants, there is urgency to understand the impacts of fire ants beyond anecdotal and singles species studies. Our results provides the first community level investigation addressing these dynamics, by manipulating fire ant abundance to reveal a response in herpetofauna species abundance and richness.

  14. Cost-Utility of Quadrivalent Versus Trivalent Influenza Vaccine in Germany, Using an Individual-Based Dynamic Transmission Model.

    PubMed

    Dolk, Christiaan; Eichner, Martin; Welte, Robert; Anastassopoulou, Anastassia; Van Bellinghen, Laure-Anne; Poulsen Nautrup, Barbara; Van Vlaenderen, Ilse; Schmidt-Ott, Ruprecht; Schwehm, Markus; Postma, Maarten

    2016-12-01

    Seasonal influenza infection is primarily caused by circulation of two influenza A strain subtypes and strains from two B lineages that vary each year. Trivalent influenza vaccine (TIV) contains only one of the two B-lineage strains, resulting in mismatches between vaccine strains and the predominant circulating B lineage. Quadrivalent influenza vaccine (QIV) includes both B-lineage strains. The objective was to estimate the cost-utility of introducing QIV to replace TIV in Germany. An individual-based dynamic transmission model (4Flu) using German data was used to provide realistic estimates of the impact of TIV and QIV on age-specific influenza infections. Cases were linked to health and economic outcomes to calculate the cost-utility of QIV versus TIV, from both a societal and payer perspective. Costs and effects were discounted at 3.0 and 1.5 % respectively, with 2014 as the base year. Univariate and probabilistic sensitivity analyses were conducted. Using QIV instead of TIV resulted in additional quality-adjusted life-years (QALYs) and cost savings from the societal perspective (i.e. it represents the dominant strategy) and an incremental cost-utility ratio (ICUR) of €14,461 per QALY from a healthcare payer perspective. In all univariate analyses, QIV remained cost-effective (ICUR <€50,000). In probabilistic sensitivity analyses, QIV was cost-effective in >98 and >99 % of the simulations from the societal and payer perspective, respectively. This analysis suggests that QIV in Germany would provide additional health gains while being cost-saving to society or costing €14,461 per QALY gained from the healthcare payer perspective, compared with TIV.

  15. A Decision Tool that Combines Discrete Event Software Process Models with System Dynamics Pieces for Software Development Cost Estimation and Analysis

    NASA Technical Reports Server (NTRS)

    Mizell, Carolyn Barrett; Malone, Linda

    2007-01-01

    The development process for a large software development project is very complex and dependent on many variables that are dynamic and interrelated. Factors such as size, productivity and defect injection rates will have substantial impact on the project in terms of cost and schedule. These factors can be affected by the intricacies of the process itself as well as human behavior because the process is very labor intensive. The complex nature of the development process can be investigated with software development process models that utilize discrete event simulation to analyze the effects of process changes. The organizational environment and its effects on the workforce can be analyzed with system dynamics that utilizes continuous simulation. Each has unique strengths and the benefits of both types can be exploited by combining a system dynamics model and a discrete event process model. This paper will demonstrate how the two types of models can be combined to investigate the impacts of human resource interactions on productivity and ultimately on cost and schedule.

  16. The Value of Heterogeneity for Cost-Effectiveness Subgroup Analysis

    PubMed Central

    Manca, Andrea; Claxton, Karl; Sculpher, Mark J.

    2014-01-01

    This article develops a general framework to guide the use of subgroup cost-effectiveness analysis for decision making in a collectively funded health system. In doing so, it addresses 2 key policy questions, namely, the identification and selection of subgroups, while distinguishing 2 sources of potential value associated with heterogeneity. These are 1) the value of revealing the factors associated with heterogeneity in costs and outcomes using existing evidence (static value) and 2) the value of acquiring further subgroup-related evidence to resolve the uncertainty given the current understanding of heterogeneity (dynamic value). Consideration of these 2 sources of value can guide subgroup-specific treatment decisions and inform whether further research should be conducted to resolve uncertainty to explain variability in costs and outcomes. We apply the proposed methods to a cost-effectiveness analysis for the management of patients with acute coronary syndrome. This study presents the expected net benefits under current and perfect information when subgroups are defined based on the use and combination of 6 binary covariates. The results of the case study confirm the theoretical expectations. As more subgroups are considered, the marginal net benefit gains obtained under the current information show diminishing marginal returns, and the expected value of perfect information shows a decreasing trend. We present a suggested algorithm that synthesizes the results to guide policy. PMID:24944196

  17. Application of Graph Theory to Cost-Effective Fire Protection of Chemical Plants During Domino Effects.

    PubMed

    Khakzad, Nima; Landucci, Gabriele; Reniers, Genserik

    2017-09-01

    In the present study, we have introduced a methodology based on graph theory and multicriteria decision analysis for cost-effective fire protection of chemical plants subject to fire-induced domino effects. By modeling domino effects in chemical plants as a directed graph, the graph centrality measures such as out-closeness and betweenness scores can be used to identify the installations playing a key role in initiating and propagating potential domino effects. It is demonstrated that active fire protection of installations with the highest out-closeness score and passive fire protection of installations with the highest betweenness score are the most effective strategies for reducing the vulnerability of chemical plants to fire-induced domino effects. We have employed a dynamic graph analysis to investigate the impact of both the availability and the degradation of fire protection measures over time on the vulnerability of chemical plants. The results obtained from the graph analysis can further be prioritized using multicriteria decision analysis techniques such as the method of reference point to find the most cost-effective fire protection strategy. © 2016 Society for Risk Analysis.

  18. The costs and cost-effectiveness of an integrated sepsis treatment protocol.

    PubMed

    Talmor, Daniel; Greenberg, Dan; Howell, Michael D; Lisbon, Alan; Novack, Victor; Shapiro, Nathan

    2008-04-01

    Sepsis is associated with high mortality and treatment costs. International guidelines recommend the implementation of integrated sepsis protocols; however, the true cost and cost-effectiveness of these are unknown. To assess the cost-effectiveness of an integrated sepsis protocol, as compared with conventional care. Prospective cohort study of consecutive patients presenting with septic shock and enrolled in the institution's integrated sepsis protocol. Clinical and economic outcomes were compared with a historical control cohort. Beth Israel Deaconess Medical Center. Overall, 79 patients presenting to the emergency department with septic shock in the treatment cohort and 51 patients in the control group. An integrated sepsis treatment protocol incorporating empirical antibiotics, early goal-directed therapy, intensive insulin therapy, lung-protective ventilation, and consideration for drotrecogin alfa and steroid therapy. In-hospital treatment costs were collected using the hospital's detailed accounting system. The cost-effectiveness analysis was performed from the perspective of the healthcare system using a lifetime horizon. The primary end point for the cost-effectiveness analysis was the incremental cost per quality-adjusted life year gained. Mortality in the treatment group was 20.3% vs. 29.4% in the control group (p = .23). Implementing an integrated sepsis protocol resulted in a mean increase in cost of approximately $8,800 per patient, largely driven by increased intensive care unit length of stay. Life expectancy and quality-adjusted life years were higher in the treatment group; 0.78 and 0.54, respectively. The protocol was associated with an incremental cost of $11,274 per life-year saved and a cost of $16,309 per quality-adjusted life year gained. In patients with septic shock, an integrated sepsis protocol, although not cost-saving, appears to be cost-effective and compares very favorably to other commonly delivered acute care interventions.

  19. Synergetic Effect of Dy2O3 and Ca Co-Dopants towards Enhanced Coercivity of Rare Earth Abundant RE-Fe-B Magnets.

    PubMed

    Li, Yingfei; Tian, Na; Fan, Xiaodong; You, Caiyin; Pei, Wenli; Cheng, Zhenxiang

    2017-12-13

    Low coercivity is the main disadvantage of RE-Fe-B permanent magnets containing highly abundant rare earths (RE: La, Ce) from the application point of view, even though they exhibit many cost and resource advantages. In this work, an industrial mixed rare earth alloy (RE 100  = La 30.6 Ce 50.2 Pr 6.4 Nd 12.8 ) with a high amount of the more abundant elements was adopted to fabricate RE-Fe-B permanent magnets by means of mechanical alloying accompanied by post-annealing. A synergetic effect towards enhancing the coercivity was observed after co-doping with Dy 2 O 3 and Ca, with the coercivity increasing from 2.44 kOe to 11.43 kOe for co-dopant percentages of 7 wt.% Dy 2 O 3  + 2.3 wt.% Ca. Through analysis of the phase constituents and microstructure, it was determined that part of the Dy atoms entered the matrix of RE 2 Fe 14 B phase to enhance the magnetocrystalline anisotropy; due to the reductive effect of Ca on Dy 2 O 3 , nanocrystals of Dy-rich RE 2 Fe 14 B were present throughout the matrix, which could increase the resistance to domain wall movement. These are the dominant factors behind the improvement of the coercivity of the RE-Fe-B magnets with highly abundant RE elements.

  20. Long-term healthcare cost reduction with Intensive Short-term Dynamic Psychotherapy in a tertiary psychiatric service.

    PubMed

    Abbass, Allan; Kisely, Steve; Rasic, Daniel; Town, Joel M; Johansson, Robert

    2015-05-01

    To evaluate whether a mixed population of patients treated with Intensive Short-term Dynamic Psychotherapy (ISTDP) would exhibit reduced healthcare costs in long-term follow-up. A quasi-experimental design was employed in which data on pre- and post-treatment healthcare cost were compared for all ISTDP cases treated in a tertiary care service over a nine year period. Observed cost changes were compared with those of a control group of patients referred but never treated. Physician and hospital costs were compared to treatment cost estimates and normal population cost figures. 1082 patients were included; 890 treated cases for a broad range of somatic and psychiatric disorders and 192 controls. The treatment averaged 7.3 sessions and measures of symptoms and interpersonal problems significantly improved. The average cost reduction per treated case was $12,628 over 3 follow-up years: this compared favorably with the estimated treatment cost of $708 per patient. Significant differences were seen between groups for follow-up hospital costs. ISTDP in this setting appears to facilitate reductions in healthcare costs, supporting the notion that brief dynamic psychotherapy provided in a tertiary setting can be beneficial to health care systems overall. CLINICALTRIALS. NCT01924715. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. The flying classroom - a cost effective integrated approach to learning and teaching flight dynamics

    NASA Astrophysics Data System (ADS)

    Bromfield, Michael A.; Belberov, Aleksandar

    2017-11-01

    In the UK, the Royal Aeronautical Society recommends the inclusion of practical flight exercises for accredited undergraduate aerospace engineering programmes to enhance learning and student experience. The majority of academic institutions teaching aerospace in the UK separate the theory and practice of flight dynamics with students attending a series of lectures supplemented by an intensive one-day flight exercise. Performance and/or handling qualities flight tests are performed in a dedicated aircraft fitted with specialist equipment for the recording and presentation of flight data. This paper describes an innovative approach to better integrate theory and practice and the use of portable Commercial-off-The-Shelf (COTS) technologies to enable a range of standard, unmodified aircraft to be used. The integration of theory and practice has enriched learning and teaching, improved coursework grades and the student experience. The use of COTS and unmodified aircraft has reduced costs and enabled increased student participation.

  2. Cost-effectiveness thresholds: pros and cons.

    PubMed

    Bertram, Melanie Y; Lauer, Jeremy A; De Joncheere, Kees; Edejer, Tessa; Hutubessy, Raymond; Kieny, Marie-Paule; Hill, Suzanne R

    2016-12-01

    Cost-effectiveness analysis is used to compare the costs and outcomes of alternative policy options. Each resulting cost-effectiveness ratio represents the magnitude of additional health gained per additional unit of resources spent. Cost-effectiveness thresholds allow cost-effectiveness ratios that represent good or very good value for money to be identified. In 2001, the World Health Organization's Commission on Macroeconomics in Health suggested cost-effectiveness thresholds based on multiples of a country's per-capita gross domestic product (GDP). In some contexts, in choosing which health interventions to fund and which not to fund, these thresholds have been used as decision rules. However, experience with the use of such GDP-based thresholds in decision-making processes at country level shows them to lack country specificity and this - in addition to uncertainty in the modelled cost-effectiveness ratios - can lead to the wrong decision on how to spend health-care resources. Cost-effectiveness information should be used alongside other considerations - e.g. budget impact and feasibility considerations - in a transparent decision-making process, rather than in isolation based on a single threshold value. Although cost-effectiveness ratios are undoubtedly informative in assessing value for money, countries should be encouraged to develop a context-specific process for decision-making that is supported by legislation, has stakeholder buy-in, for example the involvement of civil society organizations and patient groups, and is transparent, consistent and fair.

  3. Vaccination strategies for future influenza pandemics: a severity-based cost effectiveness analysis

    PubMed Central

    2013-01-01

    increased rates of vaccination further improved effectiveness and cost effectiveness. Conclusions The effectiveness and cost effectiveness consequences of the time-critical interplay of pandemic dynamics, vaccine availability and intervention timing has been quantified. For moderate and extreme pandemics, vaccination combined with rapidly activated antiviral and social distancing interventions of sufficient duration is cost effective from the perspective of life years saved. PMID:23398722

  4. Vaccination strategies for future influenza pandemics: a severity-based cost effectiveness analysis.

    PubMed

    Kelso, Joel K; Halder, Nilimesh; Milne, George J

    2013-02-11

    further improved effectiveness and cost effectiveness. The effectiveness and cost effectiveness consequences of the time-critical interplay of pandemic dynamics, vaccine availability and intervention timing has been quantified. For moderate and extreme pandemics, vaccination combined with rapidly activated antiviral and social distancing interventions of sufficient duration is cost effective from the perspective of life years saved.

  5. Projected effects of Climate-change-induced flow alterations on stream macroinvertebrate abundances.

    PubMed

    Kakouei, Karan; Kiesel, Jens; Domisch, Sami; Irving, Katie S; Jähnig, Sonja C; Kail, Jochem

    2018-03-01

    Global change has the potential to affect river flow conditions which are fundamental determinants of physical habitats. Predictions of the effects of flow alterations on aquatic biota have mostly been assessed based on species ecological traits (e.g., current preferences), which are difficult to link to quantitative discharge data. Alternatively, we used empirically derived predictive relationships for species' response to flow to assess the effect of flow alterations due to climate change in two contrasting central European river catchments. Predictive relationships were set up for 294 individual species based on (1) abundance data from 223 sampling sites in the Kinzig lower-mountainous catchment and 67 sites in the Treene lowland catchment, and (2) flow conditions at these sites described by five flow metrics quantifying the duration, frequency, magnitude, timing and rate of flow events using present-day gauging data. Species' abundances were predicted for three periods: (1) baseline (1998-2017), (2) horizon 2050 (2046-2065) and (3) horizon 2090 (2080-2099) based on these empirical relationships and using high-resolution modeled discharge data for the present and future climate conditions. We compared the differences in predicted abundances among periods for individual species at each site, where the percent change served as a proxy to assess the potential species responses to flow alterations. Climate change was predicted to most strongly affect the low-flow conditions, leading to decreased abundances of species up to -42%. Finally combining the response of all species over all metrics indicated increasing overall species assemblage responses in 98% of the studied river reaches in both projected horizons and were significantly larger in the lower-mountainous Kinzig compared to the lowland Treene catchment. Such quantitative analyses of freshwater taxa responses to flow alterations provide valuable tools for predicting potential climate-change impacts on species

  6. Abundance models improve spatial and temporal prioritization of conservation resources.

    PubMed

    Johnston, Alison; Fink, Daniel; Reynolds, Mark D; Hochachka, Wesley M; Sullivan, Brian L; Bruns, Nicholas E; Hallstein, Eric; Merrifield, Matt S; Matsumoto, Sandi; Kelling, Steve

    2015-10-01

    Conservation prioritization requires knowledge about organism distribution and density. This information is often inferred from models that estimate the probability of species occurrence rather than from models that estimate species abundance, because abundance data are harder to obtain and model. However, occurrence and abundance may not display similar patterns and therefore development of robust, scalable, abundance models is critical to ensuring that scarce conservation resources are applied where they can have the greatest benefits. Motivated by a dynamic land conservation program, we develop and assess a general method for modeling relative abundance using citizen science monitoring data. Weekly estimates of relative abundance and occurrence were compared for prioritizing times and locations of conservation actions for migratory waterbird species in California, USA. We found that abundance estimates consistently provided better rankings of observed counts than occurrence estimates. Additionally, the relationship between abundance and occurrence was nonlinear and varied by species and season. Across species, locations prioritized by occurrence models had only 10-58% overlap with locations prioritized by abundance models, highlighting that occurrence models will not typically identify the locations of highest abundance that are vital for conservation of populations.

  7. Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

    PubMed

    Turley, Nash E; Johnson, Marc T J

    2015-07-01

    Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6× larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology.

  8. Climate influences on the cost-effectiveness of vector-based interventions against malaria in elimination scenarios

    PubMed Central

    Parham, Paul E.; Hughes, Dyfrig A.

    2015-01-01

    Despite the dependence of mosquito population dynamics on environmental conditions, the associated impact of climate and climate change on present and future malaria remains an area of ongoing debate and uncertainty. Here, we develop a novel integration of mosquito, transmission and economic modelling to assess whether the cost-effectiveness of indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) against Plasmodium falciparum transmission by Anopheles gambiae s.s. mosquitoes depends on climatic conditions in low endemicity scenarios. We find that although temperature and rainfall affect the cost-effectiveness of IRS and/or LLIN scale-up, whether this is sufficient to influence policy depends on local endemicity, existing interventions, host immune response to infection and the emergence rate of insecticide resistance. For the scenarios considered, IRS is found to be more cost-effective than LLINs for the same level of scale-up, and both are more cost-effective at lower mean precipitation and higher variability in precipitation and temperature. We also find that the dependence of peak transmission on mean temperature translates into optimal temperatures for vector-based intervention cost-effectiveness. Further cost-effectiveness analysis that accounts for country-specific epidemiological and environmental heterogeneities is required to assess optimal intervention scale-up for elimination and better understand future transmission trends under climate change. PMID:25688017

  9. Experimentally reducing species abundance indirectly affects food web structure and robustness.

    PubMed

    Barbosa, Milton; Fernandes, G Wilson; Lewis, Owen T; Morris, Rebecca J

    2017-03-01

    Studies on the robustness of ecological communities suggest that the loss or reduction in abundance of individual species can lead to secondary and cascading extinctions. However, most such studies have been simulation-based analyses of the effect of primary extinction on food web structure. In a field experiment we tested the direct and indirect effects of reducing the abundance of a common species, focusing on the diverse and self-contained assemblage of arthropods associated with an abundant Brazilian shrub, Baccharis dracunculifolia D.C. (Asteraceae). Over a 5-month period we experimentally reduced the abundance of Baccharopelma dracunculifoliae (Sternorrhyncha: Psyllidae), the commonest galling species associated with B. dracunculifolia, in 15 replicate plots paired with 15 control plots. We investigated direct effects of the manipulation on parasitoids attacking B. dracunculifoliae, as well as indirect effects (mediated via a third species or through the environment) on 10 other galler species and 50 associated parasitoid species. The experimental manipulation significantly increased parasitism on B. dracunculifoliae in the treatment plots, but did not significantly alter either the species richness or abundance of other galler species. Compared to control plots, food webs in manipulated plots had significantly lower values of weighted connectance, interaction evenness and robustness (measured as simulated tolerance to secondary extinction), even when B. dracunculifoliae was excluded from calculations. Parasitoid species were almost entirely specialized to individual galler species, so the observed effects of the manipulation on food web structure could not have propagated via the documented trophic links. Instead, they must have spread either through trophic links not included in the webs (e.g. shared predators) or non-trophically (e.g. through changes in habitat availability). Our results highlight that the inclusion of both trophic and non

  10. Long-term effectiveness and cost-effectiveness of smoking cessation interventions in patients with COPD.

    PubMed

    Hoogendoorn, Martine; Feenstra, Talitha L; Hoogenveen, Rudolf T; Rutten-van Mölken, Maureen P M H

    2010-08-01

    The aim of this study was to estimate the long-term (cost-) effectiveness of smoking cessation interventions for patients with chronic obstructive pulmonary disease (COPD). A systematic review was performed of randomised controlled trials on smoking cessation interventions in patients with COPD reporting 12-month biochemical validated abstinence rates. The different interventions were grouped into four categories: usual care, minimal counselling, intensive counselling and intensive counselling + pharmacotherapy ('pharmacotherapy'). For each category the average 12-month continuous abstinence rate and intervention costs were estimated. A dynamic population model for COPD was used to project the long-term (cost-) effectiveness (25 years) of 1-year implementation of the interventions for 50% of the patients with COPD who smoked compared with usual care. Uncertainty and one-way sensitivity analyses were performed for variations in the calculation of the abstinence rates, the type of projection, intervention costs and discount rates. Nine studies were selected. The average 12-month continuous abstinence rates were estimated to be 1.4% for usual care, 2.6% for minimal counselling, 6.0% for intensive counselling and 12.3% for pharmacotherapy. Compared with usual care, the costs per quality-adjusted life year (QALY) gained for minimal counselling, intensive counselling and pharmacotherapy were euro 16 900, euro 8200 and euro 2400, respectively. The results were most sensitive to variations in the estimation of the abstinence rates and discount rates. Compared with usual care, intensive counselling and pharmacotherapy resulted in low costs per QALY gained with ratios comparable to results for smoking cessation in the general population. Compared with intensive counselling, pharmacotherapy was cost saving and dominated the other interventions.

  11. Microbial dynamics during harmful dinoflagellate Ostreopsis cf. ovata growth: Bacterial succession and viral abundance pattern.

    PubMed

    Guidi, Flavio; Pezzolesi, Laura; Vanucci, Silvana

    2018-02-27

    Algal-bacterial interactions play a major role in shaping diversity of algal associated bacterial communities. Temporal variation in bacterial phylogenetic composition reflects changes of these complex interactions which occur during the algal growth cycle as well as throughout the lifetime of algal blooms. Viruses are also known to cause shifts in bacterial community diversity which could affect algal bloom phases. This study investigated on changes of bacterial and viral abundances, bacterial physiological status, and on bacterial successional pattern associated with the harmful benthic dinoflagellate Ostreopsis cf. ovata in batch cultures over the algal growth cycle. Bacterial community phylogenetic structure was assessed by 16S rRNA gene ION torrent sequencing. A comparison between bacterial community retrieved in cultures and that one co-occurring in situ during the development of the O. cf. ovata bloom from where the algal strain was isolated was also reported. Bacterial community growth was characterized by a biphasic pattern with the highest contributions (~60%) of highly active bacteria found at the two bacterial exponential growth steps. An alphaproteobacterial consortium composed by the Rhodobacteraceae Dinoroseobacter (22.2%-35.4%) and Roseovarius (5.7%-18.3%), together with Oceanicaulis (14.2-40.3%), was strongly associated with O. cf. ovata over the algal growth. The Rhodobacteraceae members encompassed phylotypes with an assessed mutualistic-pathogenic bimodal behavior. Fabibacter (0.7%-25.2%), Labrenzia (5.6%-24.3%), and Dietzia (0.04%-1.7%) were relevant at the stationary phase. Overall, the successional pattern and the metabolic and functional traits of the bacterial community retrieved in culture mirror those ones underpinning O. cf. ovata bloom dynamics in field. Viral abundances increased synoptically with bacterial abundances during the first bacterial exponential growth step while being stationary during the second step. Microbial trends

  12. Abundance estimation and conservation biology

    USGS Publications Warehouse

    Nichols, J.D.; MacKenzie, D.I.

    2004-01-01

    should be focused on relationships between demographic processes such as survival and recruitment, the two quantities responsible for changes in abundance, rather than simply on the magnitudes of these quantities. They describe a type of Jolly–Seber capture–recapture model that permits inference about the underlying relationship between per capita recruitment rates and survival rates (Link & Barker, this volume). Implementation used Bayesian Markov Chain Monte Carlo methods and appeared to work well, yielding inferences about the relationship between recruitment and survival that were robust to selection of prior distribution. We believe that readers will find their arguments compelling, and we expect to see increased use of hierarchical modeling approaches in capture–recapture and related fields. Otto (presentation without paper) also recommended use of hierarchical models in analysis of multiple data sources dealing with population dynamics of North American mallards. He integrated survival inferences from ringing data, abundance information from aerial survey data, and recruitment information based on age ratios from a harvest survey. He used a Leslie matrix population projection model as an integrating framework and obtained estimates of breeding population size using all data.Otto’s approach also permitted inference about biases in estimated quantities. As with the work of Link & Barker (2004), we find Otto’s recommendation to use hierarchical models to integrate data from multiple sources to be very compelling. Alisauskas et al. (2004) report results of an analysis of capture–recapture data for a askatchewan population of white–winged scoters. They used the approach of Pradel (1996) to estimate population growth rate (See the PDF) directly. Estimates for 1975–1985 were quite low, but estimates for the recent period, 2000–2003,increased to values > 1. Parameter estimates for seniority, survival and per capita recruitment (Pradel, 1996) led to the

  13. Examining the patterns and dynamics of species abundance distributions in succession of forest communities by model selection.

    PubMed

    Yin, Zuo-Yun; Zeng, Lu; Luo, Shao-Ming; Chen, Ping; He, Xiao; Guo, Wei; Li, Bailian

    2018-01-01

    There are a few common species and many rare species in a biological community or a multi-species collection in given space and time. This hollow distribution curve is called species abundance distribution (SAD). Few studies have examined the patterns and dynamics of SADs during the succession of forest communities by model selection. This study explored whether the communities in different successional stages followed different SAD models and whether there existed a best SAD model to reveal their intrinsic quantitative features of structure and dynamics in succession. The abundance (the number of individuals) of each vascular plant was surveyed by quadrat sampling method from the tree, shrub and herb layers in two typical communities (i.e., the evergreen needle- and broad-leaved mixed forest and the monsoon evergreen broad-leaved forest) in southern subtropical Dinghushan Biosphere Reserve, South China. The sites of two forest communities in different successional stages are both 1 ha in area. We collected seven widely representative SAD models with obviously different function forms and transformed them into the same octave (log2) scale. These models are simultaneously confronted with eight datasets from four layers of two communities, and their goodness-of-fits to the data were evaluated by the chi-squared test, the adjusted coefficient of determination and the information criteria. The results indicated that: (1) the logCauchy model followed all the datasets and was the best among seven models; (2) the fitness of each model to the data was not directly related to the successional stage of forest community; (3) according to the SAD curves predicted by the best model (i.e., the logCauchy), the proportion of rare species decreased but that of common ones increased in the upper layers with succession, while the reverse was true in the lower layers; and (4) the difference of the SADs increased between the upper and the lower layers with succession. We concluded that

  14. Examining the patterns and dynamics of species abundance distributions in succession of forest communities by model selection

    PubMed Central

    Luo, Shao-Ming; Chen, Ping; He, Xiao; Guo, Wei; Li, Bailian

    2018-01-01

    There are a few common species and many rare species in a biological community or a multi-species collection in given space and time. This hollow distribution curve is called species abundance distribution (SAD). Few studies have examined the patterns and dynamics of SADs during the succession of forest communities by model selection. This study explored whether the communities in different successional stages followed different SAD models and whether there existed a best SAD model to reveal their intrinsic quantitative features of structure and dynamics in succession. The abundance (the number of individuals) of each vascular plant was surveyed by quadrat sampling method from the tree, shrub and herb layers in two typical communities (i.e., the evergreen needle- and broad-leaved mixed forest and the monsoon evergreen broad-leaved forest) in southern subtropical Dinghushan Biosphere Reserve, South China. The sites of two forest communities in different successional stages are both 1 ha in area. We collected seven widely representative SAD models with obviously different function forms and transformed them into the same octave (log2) scale. These models are simultaneously confronted with eight datasets from four layers of two communities, and their goodness-of-fits to the data were evaluated by the chi-squared test, the adjusted coefficient of determination and the information criteria. The results indicated that: (1) the logCauchy model followed all the datasets and was the best among seven models; (2) the fitness of each model to the data was not directly related to the successional stage of forest community; (3) according to the SAD curves predicted by the best model (i.e., the logCauchy), the proportion of rare species decreased but that of common ones increased in the upper layers with succession, while the reverse was true in the lower layers; and (4) the difference of the SADs increased between the upper and the lower layers with succession. We concluded that

  15. Anomalous abundances of solar energetic particles and coronal gas: Coulomb effects and First Ionization Potential (FIP) ordering

    NASA Technical Reports Server (NTRS)

    Mullan, D. J.

    1985-01-01

    The first ionization potential (FIP) ordering of elemental abundances in solar energetic particles and in the corona which can both be explained Coulomb effects is discussed. Solar energetic particles (SEP) and coronal gas have anomalous abundances relative to the photosphere. The anomalies are similar in both cases: which led to the conclusion that SEP acceleration is not selective, but merely preserves the source abundances. It is argued that SEP acceleration can be selective, because identical selectivity operates to determine the coronal abundances. The abundance anomalies are ordered by first ionization potential (FIP).

  16. Seasonal abundance of the navel orangeworm, Amyelois transitella, in figs and the effect of peripheral aerosol dispensers on sexual communication.

    PubMed

    Burks, Charles S; Brandl, David G

    2004-01-01

    We used flight traps baited with unmated female navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae) to examine, over two growing seasons, seasonal changes in the abundance of males in fig orchards and the impact of release of 48 mg per ha per day of the pheromone component (Z,Z)-11,13-hexadecadienal from peripherally-located timed-release dispensers on the ability of males to find unmated females within 16-ha treatment plots. Material was placed out and mating disruption was commenced at the beginning of April in the first year, and at the beginning of July the second year. This technique effectively prevented males from finding females in female-baited traps placed throughout the plot. Navel orangeworm abundance was high in figs during the first and third flight, but lower in June and July during the second flight. Since Calimyrna figs are not susceptible to attack by navel orangeworm until mid-to-late July, these findings suggest that materials cost can be reduced by beginning treatment later. Implications for insect pest management in figs and other California crops are discussed.

  17. Seasonal abundance of the navel orangeworm, Amyelois transitella, in figs and the effect of peripheral aerosol dispensers on sexual communication

    PubMed Central

    Burks, Charles S.; Brandl, David G.

    2004-01-01

    We used flight traps baited with unmated female navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae) to examine, over two growing seasons, seasonal changes in the abundance of males in fig orchards and the impact of release of 48 mg per ha per day of the pheromone component (Z,Z)-11,13-hexadecadienal from peripherally-located timed-release dispensers on the ability of males to find unmated females within 16-ha treatment plots. Material was placed out and mating disruption was commenced at the beginning of April in the first year, and at the beginning of July the second year. This technique effectively prevented males from finding females in female-baited traps placed throughout the plot. Navel orangeworm abundance was high in figs during the first and third flight, but lower in June and July during the second flight. Since Calimyrna figs are not susceptible to attack by navel orangeworm until mid-to-late July, these findings suggest that materials cost can be reduced by beginning treatment later. Implications for insect pest management in figs and other California crops are discussed. PMID:15861255

  18. The cost-effectiveness of harm reduction.

    PubMed

    Wilson, David P; Donald, Braedon; Shattock, Andrew J; Wilson, David; Fraser-Hurt, Nicole

    2015-02-01

    HIV prevalence worldwide among people who inject drugs (PWID) is around 19%. Harm reduction for PWID includes needle-syringe programs (NSPs) and opioid substitution therapy (OST) but often coupled with antiretroviral therapy (ART) for people living with HIV. Numerous studies have examined the effectiveness of each harm reduction strategy. This commentary discusses the evidence of effectiveness of the packages of harm reduction services and their cost-effectiveness with respect to HIV-related outcomes as well as estimate resources required to meet global and regional coverage targets. NSPs have been shown to be safe and very effective in reducing HIV transmission in diverse settings; there are many historical and very recent examples in diverse settings where the absence of, or reduction in, NSPs have resulted in exploding HIV epidemics compared to controlled epidemics with NSP implementation. NSPs are relatively inexpensive to implement and highly cost-effective according to commonly used willingness-to-pay thresholds. There is strong evidence that substitution therapy is effective, reducing the risk of HIV acquisition by 54% on average among PWID. OST is relatively expensive to implement when only HIV outcomes are considered; other societal benefits substantially improve the cost-effectiveness ratios to be highly favourable. Many studies have shown that ART is cost-effective for keeping people alive but there is only weak supportive, but growing evidence, of the additional effectiveness and cost-effectiveness of ART as prevention among PWID. Packages of combined harm reduction approaches are highly likely to be more effective and cost-effective than partial approaches. The coverage of harm reduction programs remains extremely low across the world. The total annual costs of scaling up each of the harm reduction strategies from current coverage levels, by region, to meet WHO guideline coverage targets are high with ART greatest, followed by OST and then NSPs. But

  19. Cost-Effective Fuel Treatment Planning

    NASA Astrophysics Data System (ADS)

    Kreitler, J.; Thompson, M.; Vaillant, N.

    2014-12-01

    The cost of fighting large wildland fires in the western United States has grown dramatically over the past decade. This trend will likely continue with growth of the WUI into fire prone ecosystems, dangerous fuel conditions from decades of fire suppression, and a potentially increasing effect from prolonged drought and climate change. Fuel treatments are often considered the primary pre-fire mechanism to reduce the exposure of values at risk to wildland fire, and a growing suite of fire models and tools are employed to prioritize where treatments could mitigate wildland fire damages. Assessments using the likelihood and consequence of fire are critical because funds are insufficient to reduce risk on all lands needing treatment, therefore prioritization is required to maximize the effectiveness of fuel treatment budgets. Cost-effectiveness, doing the most good per dollar, would seem to be an important fuel treatment metric, yet studies or plans that prioritize fuel treatments using costs or cost-effectiveness measures are absent from the literature. Therefore, to explore the effect of using costs in fuel treatment planning we test four prioritization algorithms designed to reduce risk in a case study examining fuel treatments on the Sisters Ranger District of central Oregon. For benefits we model sediment retention and standing biomass, and measure the effectiveness of each algorithm by comparing the differences among treatment and no treat alternative scenarios. Our objective is to maximize the averted loss of net benefits subject to a representative fuel treatment budget. We model costs across the study landscape using the My Fuel Treatment Planner software, tree list data, local mill prices, and GIS-measured site characteristics. We use fire simulations to generate burn probabilities, and estimate fire intensity as conditional flame length at each pixel. Two prioritization algorithms target treatments based on cost-effectiveness and show improvements over those

  20. Antiviral agents for influenza: a comparison of cost-effectiveness data.

    PubMed

    Lynd, Larry D; Goeree, Ron; O'Brien, Bernie J

    2005-01-01

    in all studies consistently reported a strong influence of the population prevalence or diagnostic accuracy of influenza on the cost effectiveness of all strategies. Baseline influenza prevalence varied widely between studies, ranging from 15% to 68%. There was also a wide variation in the assumption about the disutility of influenza (ranging from -0.137 to -0.983 for the elderly requiring hospitalisation), which also impacted the cost effectiveness. Given the variation in the ICERs of antiviral treatment and prophylaxis, the uncertainty around many model parameters, and the dynamic nature of influenza from year to year, one can only conclude that antiviral treatment or prophylaxis for influenza is likely to be more cost effective in specific populations at specific times during the influenza season, and during influenza seasons when the population prevalence reaches epidemic levels or there is mismatch between the vaccine and the circulating virus.

  1. Ion propulsion cost effectivity

    NASA Technical Reports Server (NTRS)

    Zafran, S.; Biess, J. J.

    1978-01-01

    Ion propulsion modules employing 8-cm thrusters and 30-cm thrusters were studied for Multimission Modular Spacecraft (MMS) applications. Recurring and nonrecurring cost elements were generated for these modules. As a result, ion propulsion cost drivers were identified to be Shuttle charges, solar array, power processing, and thruster costs. Cost effective design approaches included short length module configurations, array power sharing, operation at reduced thruster input power, simplified power processing units, and power processor output switching. The MMS mission model employed indicated that nonrecurring costs have to be shared with other programs unless the mission model grows. Extended performance missions exhibited the greatest benefits when compared with monopropellant hydrazine propulsion.

  2. Is AF Ablation Cost Effective?

    PubMed Central

    Martin-Doyle, William; Reynolds, Matthew R.

    2010-01-01

    The use of catheter ablation to treat AF is increasing rapidly, but there is presently an incomplete understanding of its cost-effectiveness. AF ablation procedures involve significant up-front expenditures, but multiple randomized trials have demonstrated that ablation is more effective than antiarrhythmic drugs at maintaining sinus rhythm in a second-line and possibly first-line rhythm control setting. Although truly long-term data are limited, ablation, as compared with antiarrrhythmic drugs, also appears associated with improved symptoms and quality of life and a reduction in downstream hospitalization and other health care resource utilization. Several groups have developed cost effectiveness models comparing AF ablation primarily to antiarrhythmic drugs and the model results suggest that ablation likely falls within the range generally accepted as cost-effective in developed nations. This paper will review available information on the cost-effectiveness of catheter ablation for the treatment of atrial fibrillation, and discuss continued areas of uncertainty where further research is required. PMID:20936083

  3. Effects of weather on the abundance and distribution on populations of 103 breeding bird species across the United States

    NASA Astrophysics Data System (ADS)

    Allstadt, A. J.; Gorzo, J.; Bateman, B. L.; Heglund, P. J.; Pidgeon, A. M.; Thogmartin, W.; Vavrus, S. J.; Radeloff, V.

    2016-12-01

    Often, fewer birds are often observed in an area experiencing extreme weather, as local populations tend to leave an area (via out-migration or concentration in refugia) or experience a change in population size (via mortality or reduced fecundity). Further, weather patterns are often coherent over large areas so unsuitable weather may threaten large portions of an entire species range simultaneously. However, beyond a few iconic irruptive species, rarely have studies applied both the necessary scale and sensitivity required to assess avian population responses over entire species range. Here, we examined the effects of pre-breeding season weather on the distribution and abundances of 103 North American bird species from the late 1966-2010 using observed abundance records from the Breeding Bird Survey. We compared abundances with measures of drought and temperature over each species' range, and with three atmospheric teleconnections that describe large-scale circulation patterns influencing conditions on the ground. More than 90% of the species responded to at least one of our five weather variables. Grassland bird species tended to be most responsive to weather conditions and forest birds the least, though we found relations among all habitat types. For most species, the response was movement rather than large effects on the overall population size. Maps of these responses indicate that concentration and out-migration are both common strategies for coping with challenging weather conditions across a species range. The dynamic distribution of many bird species makes clear the need to account for temporal variability in conservation planning, as areas that are less important for a species' breeding success in most years may be very important in years with abnormal weather conditions.

  4. Cost-effectiveness of hepatitis C virus antiviral treatment for injection drug user populations.

    PubMed

    Martin, Natasha K; Vickerman, Peter; Miners, Alec; Foster, Graham R; Hutchinson, Sharon J; Goldberg, David J; Hickman, Matthew

    2012-01-01

    Injecting drug use is the main risk of hepatitis C virus (HCV) transmission in most developed countries. HCV antiviral treatment (peginterferon-α + ribavirin) has been shown to be cost-effective for patients with no reinfection risk. We examined the cost-effectiveness of providing antiviral treatment for injecting drug users (IDUs) as compared with treating ex/non-IDUs or no treatment. A dynamic model of HCV transmission and disease progression was developed, incorporating: a fixed number of antiviral treatments allocated at the mild HCV stage over 10 years, no retreatment after treatment failure, potential reinfection, and three baseline IDU HCV chronic prevalence scenarios (20%, 40%, and 60%). We performed a probabilistic cost-utility analysis estimating long-term costs and outcomes measured in quality adjusted life years (QALYs) and calculating the incremental cost-effectiveness ratio (ICER) comparing treating IDUs, ex/non-IDUs, or no treatment. Antiviral treatment for IDUs is the most cost-effective option in the 20% and 40% baseline chronic prevalence settings, with ICERs compared with no treatment of £ 521 and £ 2,539 per QALY saved, respectively. Treatment of ex/non-IDUs is dominated in these scenarios. At 60% baseline prevalence, treating ex/non-IDUs is slightly more likely to be the more cost-effective option (with an ICER compared with no treatment of £ 6,803), and treating IDUs dominated due to high reinfection. A sensitivity analysis indicates these rankings hold even when IDU sustained viral response rates as compared with ex/non-IDUs are halved. Despite the possibility of reinfection, the model suggests providing antiviral treatment to IDUs is the most cost-effective policy option in chronic prevalence scenarios less than 60%. Further research on how HCV treatment for injectors can be scaled up and its impact on prevalence is warranted. Copyright © 2011 American Association for the Study of Liver Diseases.

  5. Impact and cost-effectiveness of chlamydia testing in Scotland: a mathematical modelling study.

    PubMed

    Looker, Katharine J; Wallace, Lesley A; Turner, Katherine M E

    2015-01-15

    Chlamydia is the most common sexually transmitted bacterial infection in Scotland, and is associated with potentially serious reproductive outcomes, including pelvic inflammatory disease (PID) and tubal factor infertility (TFI) in women. Chlamydia testing in Scotland is currently targeted towards symptomatic individuals, individuals at high risk of existing undetected infection, and young people. The cost-effectiveness of testing and treatment to prevent PID and TFI in Scotland is uncertain. A compartmental deterministic dynamic model of chlamydia infection in 15-24 year olds in Scotland was developed. The model was used to estimate the impact of a change in testing strategy from baseline (16.8% overall testing coverage; 0.4 partners notified and tested/treated per treated positive index) on PID and TFI cases. Cost-effectiveness calculations informed by best-available estimates of the quality-adjusted life years (QALYs) lost due to PID and TFI were also performed. Increasing overall testing coverage by 50% from baseline to 25.2% is estimated to result in 21% fewer cases in young women each year (PID: 703 fewer; TFI: 88 fewer). A 50% decrease to 8.4% would result in 20% more PID (669 additional) and TFI (84 additional) cases occurring annually. The cost per QALY gained of current testing activities compared to no testing is £40,034, which is above the £20,000-£30,000 cost-effectiveness threshold. However, calculations are hampered by lack of reliable data. Any increase in partner notification from baseline would be cost-effective (incremental cost per QALY gained for a partner notification efficacy of 1 compared to baseline: £5,119), and would increase the cost-effectiveness of current testing strategy compared to no testing, with threshold cost-effectiveness reached at a partner notification efficacy of 1.5. However, there is uncertainty in the extent to which partner notification is currently done, and hence the amount by which it could potentially be

  6. North American Brant: Effects of changes in habitat and climate on population dynamics

    USGS Publications Warehouse

    Ward, David H.; Reed, Austin; Sedinger, James S.; Black, Jeffrey M.; Derksen, Dirk V.; Castelli, Paul M.

    2005-01-01

    We describe the importance of key habitats used by four nesting populations of nearctic brant (Branta bernicla) and discuss the potential relationship between changes in these habitats and population dynamics of brant. Nearctic brant, in contrast to most geese, rely on marine habitats and native intertidal plants during the non-breeding season, particularly the seagrass, Zostera, and the macroalgae, Ulva. Atlantic and Eastern High Arctic brant have experienced the greatest degradation of their winter habitats (northeastern United States and Ireland, respectively) and have also shown the most plasticity in feeding behavior. Black and Western High Arctic brant of the Pacific Flyway are the most dependent on Zostera, and are undergoing a shift in winter distribution that is likely related to climate change and its associated effects on Zostera dynamics. Variation in breeding propensity of Black Brant associated with winter location and climate strongly suggests that food abundance on the wintering grounds directly affects reproductive performance in these geese. In summer, salt marshes, especially those containing Carex and Puccinellia, are key habitats for raising young, while lake shorelines with fine freshwater grasses and sedges are important for molting birds. Availability and abundance of salt marshes has a direct effect on growth and recruitment of goslings and ultimately, plays an important role in regulating size of local brant populations. ?? 2005 Blackwell Publishing Ltd.

  7. Uncoupling the Effects of Seed Predation and Seed Dispersal by Granivorous Ants on Plant Population Dynamics

    PubMed Central

    Arnan, Xavier; Molowny-Horas, Roberto; Rodrigo, Anselm; Retana, Javier

    2012-01-01

    Secondary seed dispersal is an important plant-animal interaction, which is central to understanding plant population and community dynamics. Very little information is still available on the effects of dispersal on plant demography and, particularly, for ant-seed dispersal interactions. As many other interactions, seed dispersal by animals involves costs (seed predation) and benefits (seed dispersal), the balance of which determines the outcome of the interaction. Separate quantification of each of them is essential in order to understand the effects of this interaction. To address this issue, we have successfully separated and analyzed the costs and benefits of seed dispersal by seed-harvesting ants on the plant population dynamics of three shrub species with different traits. To that aim a stochastic, spatially-explicit individually-based simulation model has been implemented based on actual data sets. The results from our simulation model agree with theoretical models of plant response dependent on seed dispersal, for one plant species, and ant-mediated seed predation, for another one. In these cases, model predictions were close to the observed values at field. Nonetheless, these ecological processes did not affect in anyway a third species, for which the model predictions were far from the observed values. This indicates that the balance between costs and benefits associated to secondary seed dispersal is clearly related to specific traits. This study is one of the first works that analyze tradeoffs of secondary seed dispersal on plant population dynamics, by disentangling the effects of related costs and benefits. We suggest analyzing the effects of interactions on population dynamics as opposed to merely analyzing the partners and their interaction strength. PMID:22880125

  8. In Search of Cost-Effective Schools.

    ERIC Educational Resources Information Center

    Raywid, Mary Anne; Shaheen, Thomas A.

    1994-01-01

    Examines major cost-effectiveness proposals, describing developments that highlight concerns over making schools cost effective. The article discusses ways to blend the concerns of educational quality, equity, and costs (district consolidations, shared service and facilities arrangements, new accountability strategies, new information systems,…

  9. How rebates, copayments, and administration costs affect the cost-effectiveness of osteoporosis therapies.

    PubMed

    Ferko, Nicole C; Borisova, Natalie; Airia, Parisa; Grima, Daniel T; Thompson, Melissa F

    2012-11-01

    Because of rising drug expenditures, cost considerations have become essential, necessitating the requirement for cost-effectiveness analyses for managed care organizations (MCOs). The study objective is to examine the impact of various drug-cost components, in addition to wholesale acquisition cost (WAC), on the cost-effectiveness of osteoporosis therapies. A Markov model of osteoporosis was used to exemplify different drug cost scenarios. We examined the effect of varying rebates for oral bisphosphonates--risedronate and ibandronate--as well as considering the impact of varying copayments and administration costs for intravenous zoledronate. The population modeled was 1,000 American women, > or = 50 years with osteoporosis. Patients were followed for 1 year to reflect an annual budget review of formularies by MCOs. The cost of therapy was based on an adjusted WAC, and is referred to as net drug cost. The total annual cost incurred by an MCO for each drug regimen was calculated using the net drug cost and fracture cost. We estimated cost on a quality adjusted life year (QALY) basis. When considering different rebates, results for risedronate versus ibandronate vary from cost-savings (i.e., costs less and more effective) to approximately $70,000 per QALY. With no risedronate rebate, an ibandronate rebate of approximately 65% is required before cost per QALY surpasses $50,000. With rebates greater than 25% for risedronate, irrespective of ibandronate rebates, results become cost-saving. Results also showed the magnitude of cost savings to the MCO varied by as much as 65% when considering no administration cost and the highest coinsurance rate for zoledronate. Our study showed that cost-effectiveness varies considerably when factors in addition to the WAC are considered. This paper provides recommendations for pharmaceutical manufacturers and MCOs when developing and interpreting such analyses.

  10. Costs and cost-effectiveness of delivering intermittent preventive treatment through schools in western Kenya

    PubMed Central

    Temperley, Matilda; Mueller, Dirk H; Njagi, J Kiambo; Akhwale, Willis; Clarke, Siân E; Jukes, Matthew CH; Estambale, Benson BA; Brooker, Simon

    2008-01-01

    Background Awareness of the potential impact of malaria among school-age children has stimulated investigation into malaria interventions that can be delivered through schools. However, little evidence is available on the costs and cost-effectiveness of intervention options. This paper evaluates the costs and cost-effectiveness of intermittent preventive treatment (IPT) as delivered by teachers in schools in western Kenya. Methods Information on actual drug and non-drug associated costs were collected from expenditure and salary records, government budgets and interviews with key district and national officials. Effectiveness data were derived from a cluster-randomised-controlled trial of IPT where a single dose of sulphadoxine-pyrimethamine and three daily doses of amodiaquine were provided three times in year (once termly). Both financial and economic costs were estimated from a provider perspective, and effectiveness was estimated in terms of anaemia cases averted. A sensitivity analysis was conducted to assess the impact of key assumptions on estimated cost-effectiveness. Results The delivery of IPT by teachers was estimated to cost US$ 1.88 per child treated per year, with drug and teacher training costs constituting the largest cost components. Set-up costs accounted for 13.2% of overall costs (equivalent to US$ 0.25 per child) whilst recurrent costs accounted for 86.8% (US$ 1.63 per child per year). The estimated cost per anaemia case averted was US$ 29.84 and the cost per case of Plasmodium falciparum parasitaemia averted was US$ 5.36, respectively. The cost per case of anaemia averted ranged between US$ 24.60 and 40.32 when the prices of antimalarial drugs and delivery costs were varied. Cost-effectiveness was most influenced by effectiveness of IPT and the background prevalence of anaemia. In settings where 30% and 50% of schoolchildren were anaemic, cost-effectiveness ratios were US$ 12.53 and 7.52, respectively. Conclusion This study provides the first

  11. Scale-dependent effects of nonnative plant invasion on host-seeking tick abundance

    PubMed Central

    Adalsteinsson, Solny A.; D’Amico, Vincent; Shriver, W. Gregory; Brisson, Dustin; Buler, Jeffrey J.

    2016-01-01

    Nonnative, invasive shrubs can affect human disease risk through direct and indirect effects on vector populations. Multiflora rose (Rosa multiflora) is a common invader within eastern deciduous forests where tick-borne disease (e.g. Lyme disease) rates are high. We tested whether R. multiflora invasion affects blacklegged tick (Ixodes scapularis) abundance, and at what scale. We sampled host-seeking ticks at two spatial scales: fine-scale, within R. multiflora-invaded forest fragments; and patch scale, among R. multiflora-invaded and R. multiflora-free forest fragments. At a fine scale, we trapped 2.3 times more ticks under R. multiflora compared to paired traps 25 m away from R. multiflora. At the patch scale, we trapped 3.2 times as many ticks in R. multiflora-free forests compared to R. multiflora-invaded forests. Thus, ticks are concentrated beneath R. multiflora within invaded forests, but uninvaded forests support significantly more ticks. Among all covariates tested, leaf litter volume was the best predictor of tick abundance; at the patch scale, R. multiflora-invaded forests had less leaf litter than uninvaded forests. We suggest that leaf litter availability at the patch-scale plays a greater role in constraining tick abundance than the fine-scale, positive effect of invasive shrubs. PMID:27088044

  12. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

    PubMed

    Garzke, Jessica; Hansen, Thomas; Ismar, Stefanie M H; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.

  13. Indirect effects of predators control herbivore richness and abundance in a benthic eelgrass (Zostera marina) mesograzer community.

    PubMed

    Amundrud, Sarah L; Srivastava, Diane S; O'Connor, Mary I

    2015-07-01

    Herbivore communities can be sensitive to changes in predator pressure (top-down effects) and resource availability (bottom-up effects) in a wide range of systems. However, it remains unclear whether such top-down and bottom-up effects reflect direct impacts of predators and/or resources on herbivores, or are indirect, reflecting altered interactions among herbivore species. We quantified direct and indirect effects of bottom-up and top-down processes on an eelgrass (Zostera marina) herbivore assemblage. In a field experiment, we factorially manipulated water column nutrients (with Osmocote(™) slow-release fertilizer) and predation pressure (with predator exclusion cages) and measured the effects on herbivore abundance, richness and beta diversity. We examined likely mechanisms of community responses by statistically exploring the response of individual herbivore species to trophic manipulations. Predators increased herbivore richness and total abundance, in both cases through indirect shifts in community composition. Increases in richness occurred through predator suppression of common gammarid amphipod species (Monocorophium acherusicum and Photis brevipes), permitting the inclusion of rarer gammarid species (Aoroides columbiae and Pontogeneia rostrata). Increased total herbivore abundance reflected increased abundance of a caprellid amphipod species (Caprella sp.), concurrent with declines in the abundance of other common species. Furthermore, predators decreased beta diversity by decreasing variability in Caprella sp. abundance among habitat patches. Osmocote(™) fertilization increased nutrient concentrations locally, but nutrients dissipated to background levels within 3 m of the fertilizer. Nutrient addition weakly affected the herbivore assemblage, not affecting richness and increasing total abundance by increasing one herbivore species (Caprella sp.). Nutrient addition did not affect beta diversity. We demonstrated that assemblage-level effects of

  14. Effect of climate-ocean changes on the abundance of Pacific saury.

    PubMed

    Gong, Yeong; Suh, Young Sang

    2013-01-01

    Effects of ocean climate changes on the population structure and abundance of Pacific saury (Cololabis sira) were investigated on the basis of climate indices, sea surface temperature (SST) anomalies, catch and body size information from the Tsushima Warm Current (TWC) region (Yellow Sea, East China Sea and East/Japan Sea) during the period 1950-2010. It is suggested that oceanic regime shifts in the early 1970s, late 1980s and late 1990s occurred in the TWC region in winter, but the regime shifts in the mid-1970s and in the late 1980s were not evident in the spring SST anomaly series. The abundance and body size of Pacific saury fluctuated in association with the winter oceanic changes in the TWC region. The catch rates and abundance of large size saury were far bellow average during their northward migrations in the TWC region in the years with abnormally cool winters (e.g., 1963, 1970, 1977, 1981-1989 and 2006) and above average in the years with warm winters. These patterns demonstrate decadal-scale variations together with large inter-annual fluctuations in the structure and abundance of Pacific saury in association with the climatic-oceanic changes. These results, along with an alternation of dominant pelagic fish species, indicate the status of the saury population in the TWC region is in good condition, similar to that in the Kuroshio-Oyashio Current (KOC) region during the warm regime after the late 1980s climate regime shift.

  15. Climate influences on the cost-effectiveness of vector-based interventions against malaria in elimination scenarios.

    PubMed

    Parham, Paul E; Hughes, Dyfrig A

    2015-04-05

    Despite the dependence of mosquito population dynamics on environmental conditions, the associated impact of climate and climate change on present and future malaria remains an area of ongoing debate and uncertainty. Here, we develop a novel integration of mosquito, transmission and economic modelling to assess whether the cost-effectiveness of indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) against Plasmodium falciparum transmission by Anopheles gambiae s.s. mosquitoes depends on climatic conditions in low endemicity scenarios. We find that although temperature and rainfall affect the cost-effectiveness of IRS and/or LLIN scale-up, whether this is sufficient to influence policy depends on local endemicity, existing interventions, host immune response to infection and the emergence rate of insecticide resistance. For the scenarios considered, IRS is found to be more cost-effective than LLINs for the same level of scale-up, and both are more cost-effective at lower mean precipitation and higher variability in precipitation and temperature. We also find that the dependence of peak transmission on mean temperature translates into optimal temperatures for vector-based intervention cost-effectiveness. Further cost-effectiveness analysis that accounts for country-specific epidemiological and environmental heterogeneities is required to assess optimal intervention scale-up for elimination and better understand future transmission trends under climate change. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  16. Cost-effectiveness Analysis for Technology Acquisition.

    PubMed

    Chakravarty, A; Naware, S S

    2008-01-01

    In a developing country with limited resources, it is important to utilize the total cost visibility approach over the entire life-cycle of the technology and then analyse alternative options for acquiring technology. The present study analysed cost-effectiveness of an "In-house" magnetic resonance imaging (MRI) scan facility of a large service hospital against outsourcing possibilities. Cost per unit scan was calculated by operating costing method and break-even volume was calculated. Then life-cycle cost analysis was performed to enable total cost visibility of the MRI scan in both "In-house" and "outsourcing of facility" configuration. Finally, cost-effectiveness analysis was performed to identify the more acceptable decision option. Total cost for performing unit MRI scan was found to be Rs 3,875 for scans without contrast and Rs 4,129 with contrast. On life-cycle cost analysis, net present value (NPV) of the "In-house" configuration was found to be Rs-(4,09,06,265) while that of "outsourcing of facility" configuration was Rs-(5,70,23,315). Subsequently, cost-effectiveness analysis across eight Figures of Merit showed the "In-house" facility to be the more acceptable option for the system. Every decision for acquiring high-end technology must be subjected to life-cycle cost analysis.

  17. Effect from low-level exposure of oxytetracycline on abundance of tetracycline resistance genes in arable soils.

    PubMed

    Shentu, Jia-Li; Zhang, Kun; Shen, Dong-Sheng; Wang, Mei-Zhen; Feng, Hua-Jun

    2015-09-01

    To evaluate the effect from low-level exposure of antibiotics on the abundance of antibiotic resistance genes, unpolluted arable soils were treated with oxytetracycline (OTC)-containing manure, with OTC (0, 2, 20, or 70 μg kg(-1)) added every 2 weeks on 10 occasions. Six tetracycline resistance genes [TRGs-tet(A), tet(L), tet(M), tet(Q), tet(O), and tet(W)] and the 16S ribosomal RNA (rRNA) gene were monitored using real-time quantitative polymerase chain reaction. The relative abundance of tet(A), tet(L), tet(M), and tet(Q) genes in soil increased 10-1000 times after application of OTC-containing manure. Tet(A) abundance per unit of residual OTC on day 140 was 1.53-4.42 times higher than that on day 28, while tet(L) abundance was 1.04-1.74 times higher. Treatment with >40 μg kg(-1) OTC significantly increased abundance of tet(A) and tet(L), while tet(M) and tet(Q) abundance was positively correlated (R (2) = 0.965 and 0.932, p < 0.01) with residual OTC concentrations. There was a significant accumulation of TRGs associated with low-level OTC exposure in arable soils. Besides OTC residual, the effects from exposure time and application frequencies should also be considered to limit the increase in abundance of tet(A) and tet(L).

  18. Temporal trends in arthropod abundances after the transition to organic farming in paddy fields.

    PubMed

    Tsutsui, Masaru H; Kobayashi, Kazuhiko; Miyashita, Tadashi

    2018-01-01

    Organic farming aims to reduce the effect on the ecosystem and enhance biodiversity in agricultural areas, but the long-term effectiveness of its application is unclear. Assessments have rarely included various taxonomic groups with different ecological and economic roles. In paddy fields with different numbers of years elapsed since the transition from conventional to organic farming, we investigated changes in the abundance of insect pests, generalist predators, and species of conservation concern. The abundance of various arthropods exhibited diverse trends with respect to years elapsed since the transition to organic farming. Larval lepidopterans, Tetragnatha spiders, and some planthoppers and stink bugs showed non-linear increases over time, eventually reaching saturation, such as the abundance increasing for several years and then becoming stable after 10 years. This pattern can be explained by the effects of residual pesticides, the lag time of soil mineralization, and dispersal limitation. A damselfly (Ischnura asiatica) did not show a particular trend over time, probably due to its rapid immigration from source habitats. Unexpectedly, both planthoppers and some leafhoppers exhibited gradual decreases over time. As their abundances were negatively related to the abundance of Tetragnatha spiders, increased predation by natural enemies might gradually decrease these insect populations. These results suggest that the consideration of time-dependent responses of organisms is essential for the evaluation of the costs and benefits of organic farming, and such evaluations could provide a basis for guidelines regarding the length of time for organic farming to restore biodiversity or the economic subsidy needed to compensate for pest damage.

  19. Temporal trends in arthropod abundances after the transition to organic farming in paddy fields

    PubMed Central

    Tsutsui, Masaru H.; Kobayashi, Kazuhiko

    2018-01-01

    Organic farming aims to reduce the effect on the ecosystem and enhance biodiversity in agricultural areas, but the long-term effectiveness of its application is unclear. Assessments have rarely included various taxonomic groups with different ecological and economic roles. In paddy fields with different numbers of years elapsed since the transition from conventional to organic farming, we investigated changes in the abundance of insect pests, generalist predators, and species of conservation concern. The abundance of various arthropods exhibited diverse trends with respect to years elapsed since the transition to organic farming. Larval lepidopterans, Tetragnatha spiders, and some planthoppers and stink bugs showed non-linear increases over time, eventually reaching saturation, such as the abundance increasing for several years and then becoming stable after 10 years. This pattern can be explained by the effects of residual pesticides, the lag time of soil mineralization, and dispersal limitation. A damselfly (Ischnura asiatica) did not show a particular trend over time, probably due to its rapid immigration from source habitats. Unexpectedly, both planthoppers and some leafhoppers exhibited gradual decreases over time. As their abundances were negatively related to the abundance of Tetragnatha spiders, increased predation by natural enemies might gradually decrease these insect populations. These results suggest that the consideration of time-dependent responses of organisms is essential for the evaluation of the costs and benefits of organic farming, and such evaluations could provide a basis for guidelines regarding the length of time for organic farming to restore biodiversity or the economic subsidy needed to compensate for pest damage. PMID:29324809

  20. Passive sampling: A cost-effective method for understanding antibiotic fate, behaviour and impact.

    PubMed

    Chen, Chang-Er; Zhang, Hao; Ying, Guang-Guo; Zhou, Li-Jun; Jones, Kevin C

    2015-12-01

    The occurrence of antibiotics in the environment has raised much concern in recent years. Understanding their release, fate and behaviour in the environment is vital to assess potential risks. In this study, a novel passive water sampler - diffusion gradients in thin-films for organics (o-DGT) - was employed to assess the occurrence and removal of antibiotics in two waste water treatment plants (WWTPs) - one in China and the other in the United Kingdom (UK). Of the targeted compounds, 11 of 19 were detected in the Chinese WWTP (ND-200ng/L) and 10 of 40 were found in the UK plant (ND-1380ng/L). Florfenicol, lincomycin, ofloxacin and roxithromycin were most abundant in the Chinese WWTP (influent), while anhydrous erythromycin, ciprofloxacin, trimethoprim, ofloxacin and sulfapyridine were the most abundant in the UK influent samples. Estimated Chinese and UK consumption data are used to interpret the results. Neither of the WWTPs was very effective at removing antibiotics: ~40-50% (overall) was removed by the two plants, with the rest being discharged into the receiving rivers. This is the first study using o-DGT to assess the occurrence and removal of antibiotics in WWTPs. o-DGT is a useful, cost-effective tool to assess WWTP performance and can highlight the effectiveness of treatment steps, which can be applied to wastewater based epidemiology studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Comparative effectiveness and cost-effectiveness of the implantable miniature telescope.

    PubMed

    Brown, Gary C; Brown, Melissa M; Lieske, Heidi B; Lieske, Philip A; Brown, Kathryn S; Lane, Stephen S

    2011-09-01

    To assess the preference-based comparative effectiveness (human value gain) and the cost-utility (cost-effectiveness) of a telescope prosthesis (implantable miniature telescope) for the treatment of end-stage, age-related macular degeneration (AMD). A value-based medicine, second-eye model, cost-utility analysis was performed to quantify the comparative effectiveness and cost-effectiveness of therapy with the telescope prosthesis. Published, evidence-based data from the IMT002 Study Group clinical trial. Ophthalmic utilities were obtained from a validated cohort of >1000 patients with ocular diseases. Comparative effectiveness data were converted from visual acuity to utility (value-based) format. The incremental costs (Medicare) of therapy versus no therapy were integrated with the value gain conferred by the telescope prosthesis to assess its average cost-utility. The incremental value gains and incremental costs of therapy referent to (1) a fellow eye cohort and (2) a fellow eye cohort of those who underwent intra-study cataract surgery were integrated in incremental cost-utility analyses. All value outcomes and costs were discounted at a 3% annual rate, as per the Panel on Cost-Effectiveness in Health and Medicine. Comparative effectiveness was quantified using the (1) quality-adjusted life-year (QALY) gain and (2) percent human value gain (improvement in quality of life). The QALY gain was integrated with incremental costs into the cost-utility ratio ($/QALY, or US dollars expended per QALY gained). The mean, discounted QALY gain associated with use of the telescope prosthesis over 12 years was 0.7577. When the QALY loss of 0.0004 attributable to the adverse events was factored into the model, the final QALY gain was 0.7573. This resulted in a 12.5% quality of life gain for the average patient during the 12 years of the model. The average cost-utility versus no therapy for use of the telescope prosthesis was $14389/QALY. The incremental cost-utility referent

  2. Cost-effectiveness analysis: role and implications.

    PubMed

    Marsden, G; Wonderling, D

    2013-03-01

    Cost-effectiveness analysis (CEA) is often misperceived to be a cost-cutting exercise. The intention of CEA is not to identify and implement cheap technologies, but rather those which offer maximum health gain, subject to available funds. Such analysis is crucial for decision making in health care, as tight budget constraints mean spending in one area of healthcare displaces spending elsewhere. Therefore in order to achieve the greatest health gain for the overall population, treatments must be selected which provide the greatest health gain within the available funds. The relevance of CEA in health care systems is explained, using varicose vein treatment in the UK NHS as an example. Treatment for varicose veins is often not commissioned to at a local level, most likely because it is misperceived to be a cosmetic problem. However, this view does not take into account the impact of quality of life. CEA balances costs against a quantitative measure of health related quality of life, and could therefore be used to determine whether it is cost-effective to provide varicose vein treatment. The current literature on the cost-effectiveness of varicose vein treatment is reviewed, and an overview of cost-effectiveness principles is provided. Concepts such as economic modelling, incremental cost-effectiveness ratios (ICERs), net monetary benefit (NMB) and sensitivity analysis are explained, using examples relevant to varicose veins where appropriate. This article explains how, far from cutting costs and sacrificing patient health, CEA provides a useful tool to maximise the health of the population in the face of ever tightening budget constraints. CEA could be used to compare the cost-effectiveness of the various treatment options for varicose veins, and efficiencies realised.

  3. Cost-Effectiveness and Cost-Utility of Internet-Based Computer Tailoring for Smoking Cessation

    PubMed Central

    Evers, Silvia MAA; de Vries, Hein; Hoving, Ciska

    2013-01-01

    Background Although effective smoking cessation interventions exist, information is limited about their cost-effectiveness and cost-utility. Objective To assess the cost-effectiveness and cost-utility of an Internet-based multiple computer-tailored smoking cessation program and tailored counseling by practice nurses working in Dutch general practices compared with an Internet-based multiple computer-tailored program only and care as usual. Methods The economic evaluation was embedded in a randomized controlled trial, for which 91 practice nurses recruited 414 eligible smokers. Smokers were randomized to receive multiple tailoring and counseling (n=163), multiple tailoring only (n=132), or usual care (n=119). Self-reported cost and quality of life were assessed during a 12-month follow-up period. Prolonged abstinence and 24-hour and 7-day point prevalence abstinence were assessed at 12-month follow-up. The trial-based economic evaluation was conducted from a societal perspective. Uncertainty was accounted for by bootstrapping (1000 times) and sensitivity analyses. Results No significant differences were found between the intervention arms with regard to baseline characteristics or effects on abstinence, quality of life, and addiction level. However, participants in the multiple tailoring and counseling group reported significantly more annual health care–related costs than participants in the usual care group. Cost-effectiveness analysis, using prolonged abstinence as the outcome measure, showed that the mere multiple computer-tailored program had the highest probability of being cost-effective. Compared with usual care, in this group €5100 had to be paid for each additional abstinent participant. With regard to cost-utility analyses, using quality of life as the outcome measure, usual care was probably most efficient. Conclusions To our knowledge, this was the first study to determine the cost-effectiveness and cost-utility of an Internet-based smoking

  4. Cost-Effectiveness and Cost-Reduction in United States Colleges and Universities.

    ERIC Educational Resources Information Center

    Miller, Richard I.; Miller, Peggy M.

    1991-01-01

    The relationship in college administration between cost effectiveness/cost reduction and planning, management, and evaluation is explored, and approaches to cost accounting and financial ratio analysis are discussed. It is concluded that it is important to emphasize institutional mission and people rather than cost containment and productivity.…

  5. Cost-Effectiveness Analysis of Universal Influenza Vaccination: Application of Susceptible-Infectious-Complication-Recovery Model.

    PubMed

    Yang, Kuen-Cheh; Hung, Hui-Fang; Chen, Meng-Kan; Chen, Li-Sheng; Fann, Jean Ching-Yuan; Chiu, Sherry Yueh-Hsia; Yen, Amy-Ming Fang; Huang, Kuo-Chin; Chen, Hsiu-Hsi; Wang, Sen-Te

    2018-06-12

    Despite the fact that vaccination is an effective primary prevention strategy for containing influenza outbreak, health policymakers show great concern over enormous costs involved in universal immunization particularly when resources are limited. We conducted a two-arm cost-effectiveness analysis (CEA) that takes into account the aspect of herd immunity, using a study cohort that was composed of 100,000 residents with the make-up of demographic characteristics identical to those of the underlying population in Taipei County, Taiwan, during the epidemic influenza season of 2001-2002. The parameters embedded in the dynamic process of infection were estimated by the application of the newly proposed susceptible-infection-complication-recovery model to the empirical data in order to compute the number of deaths and complications averted due to universal vaccination compared to non-vaccination. Incremental cost-effectiveness ratios (ICERs) and cost-effectiveness acceptability curve (CEAC) given maximum amount of willingness-to-pay (WTP) were calculated to delineate the results of the two-arm CEA. Incremental costs involved in the vaccinated group as opposed to the unvaccinated group was $1,195 for reducing one additional complication and $805 for averting one additional death, allowing for herd immunity. The corresponding figures were higher for the results without considering herd immunity. Given the ceiling ratio of willingness-to-pay (WTP) equal to $10,000 (approximately two-thirds of the GDP), the probability of being cost-effective for vaccination was 100% and 96.7% for averting death and complications, respectively. Universal vaccination against seasonal influenza was very cost-effective particularly when herd immunity is considered. The probability of being cost-effective was almost certain given the maximum amount of WTP within two-thirds of the GDP. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Empirical evidence that metabolic theory describes the temperature dependency of within-host parasite dynamics.

    PubMed

    Kirk, Devin; Jones, Natalie; Peacock, Stephanie; Phillips, Jessica; Molnár, Péter K; Krkošek, Martin; Luijckx, Pepijn

    2018-02-01

    The complexity of host-parasite interactions makes it difficult to predict how host-parasite systems will respond to climate change. In particular, host and parasite traits such as survival and virulence may have distinct temperature dependencies that must be integrated into models of disease dynamics. Using experimental data from Daphnia magna and a microsporidian parasite, we fitted a mechanistic model of the within-host parasite population dynamics. Model parameters comprising host aging and mortality, as well as parasite growth, virulence, and equilibrium abundance, were specified by relationships arising from the metabolic theory of ecology. The model effectively predicts host survival, parasite growth, and the cost of infection across temperature while using less than half the parameters compared to modeling temperatures discretely. Our results serve as a proof of concept that linking simple metabolic models with a mechanistic host-parasite framework can be used to predict temperature responses of parasite population dynamics at the within-host level.

  7. Empirical evidence that metabolic theory describes the temperature dependency of within-host parasite dynamics

    PubMed Central

    Jones, Natalie; Peacock, Stephanie; Phillips, Jessica; Molnár, Péter K.; Krkošek, Martin; Luijckx, Pepijn

    2018-01-01

    The complexity of host–parasite interactions makes it difficult to predict how host–parasite systems will respond to climate change. In particular, host and parasite traits such as survival and virulence may have distinct temperature dependencies that must be integrated into models of disease dynamics. Using experimental data from Daphnia magna and a microsporidian parasite, we fitted a mechanistic model of the within-host parasite population dynamics. Model parameters comprising host aging and mortality, as well as parasite growth, virulence, and equilibrium abundance, were specified by relationships arising from the metabolic theory of ecology. The model effectively predicts host survival, parasite growth, and the cost of infection across temperature while using less than half the parameters compared to modeling temperatures discretely. Our results serve as a proof of concept that linking simple metabolic models with a mechanistic host–parasite framework can be used to predict temperature responses of parasite population dynamics at the within-host level. PMID:29415043

  8. Assessing the costs, benefits, cost-effectiveness, and cost-benefit of psychological assessment: we should, we can, and here's how.

    PubMed

    Yates, Brian T; Taub, Jennifer

    2003-12-01

    To the extent that assessment improves the effectiveness of treatment, prevention, or other services, it can be said to be effective. If an assessment is as effective as alternatives for improving treatment and less costly, it can be said to be cost-effective. If that improvement in the effectiveness of the service is monetary or monetizable, the assessment can be judged beneficial. And, if the sum of monetary and monetizable benefits of assessment exceeds the sum of the costs of treatment, the assessment can be said to be cost-beneficial. An overview of cost-related issues is followed by practical strategies that researchers and administrators can use to measure incremental costs, incremental effectiveness, and incremental benefits of adding psychological assessments to other psychological interventions.

  9. The cost and cost-effectiveness of gender-responsive interventions for HIV: a systematic review.

    PubMed

    Remme, Michelle; Siapka, Mariana; Vassall, Anna; Heise, Lori; Jacobi, Jantine; Ahumada, Claudia; Gay, Jill; Watts, Charlotte

    2014-01-01

    Harmful gender norms and inequalities, including gender-based violence, are important structural barriers to effective HIV programming. We assess current evidence on what forms of gender-responsive intervention may enhance the effectiveness of basic HIV programmes and be cost-effective. Effective intervention models were identified from an existing evidence review ("what works for women"). Based on this, we conducted a systematic review of published and grey literature on the costs and cost-effectiveness of each intervention identified. Where possible, we compared incremental costs and effects. Our effectiveness search identified 36 publications, reporting on the effectiveness of 22 HIV interventions with a gender focus. Of these, 11 types of interventions had a corresponding/comparable costing or cost-effectiveness study. The findings suggest that couple counselling for the prevention of vertical transmission; gender empowerment, community mobilization, and female condom promotion for female sex workers; expanded female condom distribution for the general population; and post-exposure HIV prophylaxis for rape survivors are cost-effective HIV interventions. Cash transfers for schoolgirls and school support for orphan girls may also be cost-effective in generalized epidemic settings. There has been limited research to assess the cost-effectiveness of interventions that seek to address women's needs and transform harmful gender norms. Our review identified several promising, cost-effective interventions that merit consideration as critical enablers in HIV investment approaches, as well as highlight that broader gender and development interventions can have positive HIV impacts. By no means an exhaustive package, these represent a first set of interventions to be included in the investment framework.

  10. On the statistical mechanics of species abundance distributions.

    PubMed

    Bowler, Michael G; Kelly, Colleen K

    2012-09-01

    A central issue in ecology is that of the factors determining the relative abundance of species within a natural community. The proper application of the principles of statistical physics to species abundance distributions (SADs) shows that simple ecological properties could account for the near universal features observed. These properties are (i) a limit on the number of individuals in an ecological guild and (ii) per capita birth and death rates. They underpin the neutral theory of Hubbell (2001), the master equation approach of Volkov et al. (2003, 2005) and the idiosyncratic (extreme niche) theory of Pueyo et al. (2007); they result in an underlying log series SAD, regardless of neutral or niche dynamics. The success of statistical mechanics in this application implies that communities are in dynamic equilibrium and hence that niches must be flexible and that temporal fluctuations on all sorts of scales are likely to be important in community structure. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Costs and cost-effectiveness of community health workers: evidence from a literature review.

    PubMed

    Vaughan, Kelsey; Kok, Maryse C; Witter, Sophie; Dieleman, Marjolein

    2015-09-01

    This study sought to synthesize and critically review evidence on costs and cost-effectiveness of community health worker (CHW) programmes in low- and middle-income countries (LMICs) to inform policy dialogue around their role in health systems. From a larger systematic review on effectiveness and factors influencing performance of close-to-community providers, complemented by a supplementary search in PubMed, we did an exploratory review of a subset of papers (32 published primary studies and 4 reviews from the period January 2003-July 2015) about the costs and cost-effectiveness of CHWs. Studies were assessed using a data extraction matrix including methodological approach and findings. Existing evidence suggests that, compared with standard care, using CHWs in health programmes can be a cost-effective intervention in LMICs, particularly for tuberculosis, but also - although evidence is weaker - in other areas such as reproductive, maternal, newborn and child health (RMNCH) and malaria. Notwithstanding important caveats about the heterogeneity of the studies and their methodological limitations, findings reinforce the hypothesis that CHWs may represent, in some settings, a cost-effective approach for the delivery of essential health services. The less conclusive evidence about the cost-effectiveness of CHWs in other areas may reflect that these areas have been evaluated less (and less rigorously) than others, rather than an actual difference in cost-effectiveness in the various service delivery areas or interventions. Methodologically, areas for further development include how to properly assess costs from a societal perspective rather than just through the lens of the cost to government and accounting for non-tangible costs and non-health benefits commonly associated with CHWs.

  12. Cost-effectiveness of vaccination against herpes zoster.

    PubMed

    de Boer, Pieter T; Wilschut, Jan C; Postma, Maarten J

    2014-01-01

    Herpes zoster (HZ) is a common disease among elderly, which may develop into a severe pain syndrome labeled postherpetic neuralgia (PHN). A live-attenuated varicella zoster virus vaccine has been shown to be effective in reducing the incidence and burden of illness of HZ and PHN, providing the opportunity to prevent significant health-related and financial consequences of HZ. In this review, we summarize the available literature on cost-effectiveness of HZ vaccination and discuss critical parameters for cost-effectiveness results. A search in PubMed and EMBASE was performed to identify full cost-effectiveness studies published before April 2013. Fourteen cost-effectiveness studies were included, all performed in western countries. All studies evaluated cost-effectiveness among elderly above 50 years and used costs per quality-adjusted life year (QALY) gained as primary outcome. The vast majority of studies showed vaccination of 60- to 75-year-old individuals to be cost-effective, when duration of vaccine efficacy was longer than 10 years. Duration of vaccine efficacy, vaccine price, HZ incidence, HZ incidence and discount rates were influential to the incremental cost-effectiveness ratio (ICER). HZ vaccination may be a worthwhile intervention from a cost-effectiveness point of view. More extensive reporting on methodology and more detailed results of sensitivity analyses would be desirable to address uncertainty and to guarantee optimal comparability between studies, for example regarding model structure, discounting, vaccine characteristics and loss of quality of life due to HZ and PHN.

  13. Cost-effectiveness of vaccination against herpes zoster

    PubMed Central

    de Boer, Pieter T; Wilschut, Jan C; Postma, Maarten J

    2014-01-01

    Herpes zoster (HZ) is a common disease among elderly, which may develop into a severe pain syndrome labeled postherpetic neuralgia (PHN). A live-attenuated varicella zoster virus vaccine has been shown to be effective in reducing the incidence and burden of illness of HZ and PHN, providing the opportunity to prevent significant health-related and financial consequences of HZ. In this review, we summarize the available literature on cost-effectiveness of HZ vaccination and discuss critical parameters for cost-effectiveness results. A search in PubMed and EMBASE was performed to identify full cost-effectiveness studies published before April 2013. Fourteen cost-effectiveness studies were included, all performed in western countries. All studies evaluated cost-effectiveness among elderly above 50 years and used costs per quality-adjusted life year (QALY) gained as primary outcome. The vast majority of studies showed vaccination of 60- to 75-year-old individuals to be cost-effective, when duration of vaccine efficacy was longer than 10 years. Duration of vaccine efficacy, vaccine price, HZ incidence, HZ incidence and discount rates were influential to the incremental cost-effectiveness ratio (ICER). HZ vaccination may be a worthwhile intervention from a cost-effectiveness point of view. More extensive reporting on methodology and more detailed results of sensitivity analyses would be desirable to address uncertainty and to guarantee optimal comparability between studies, for example regarding model structure, discounting, vaccine characteristics and loss of quality of life due to HZ and PHN. PMID:25424815

  14. Economics of infection control surveillance technology: cost-effective or just cost?

    PubMed

    Furuno, Jon P; Schweizer, Marin L; McGregor, Jessina C; Perencevich, Eli N

    2008-04-01

    Previous studies have suggested that informatics tools, such as automated alert and decision support systems, may increase the efficiency and quality of infection control surveillance. However, little is known about the cost-effectiveness of these tools. We focus on 2 types of economic analyses that have utility in assessing infection control interventions (cost-effectiveness analysis and business-case analysis) and review the available literature on the economics of computerized infection control surveillance systems. Previous studies on the effectiveness of computerized infection control surveillance have been limited to assessments of whether these tools increase the sensitivity and specificity of surveillance over traditional methods. Furthermore, we identified only 2 studies that assessed the costs associated with computerized infection control surveillance. Thus, it remains unknown whether computerized infection control surveillance systems are cost-effective and whether use of these systems improves patient outcomes. The existing data are insufficient to allow for a summary conclusion on the cost-effectiveness of infection control surveillance technology. All future studies of computerized infection control surveillance systems should aim to collect outcomes and economic data to inform decision making and assist hospitals with completing business-cases analyses.

  15. Bayesian models for cost-effectiveness analysis in the presence of structural zero costs

    PubMed Central

    Baio, Gianluca

    2014-01-01

    Bayesian modelling for cost-effectiveness data has received much attention in both the health economics and the statistical literature, in recent years. Cost-effectiveness data are characterised by a relatively complex structure of relationships linking a suitable measure of clinical benefit (e.g. quality-adjusted life years) and the associated costs. Simplifying assumptions, such as (bivariate) normality of the underlying distributions, are usually not granted, particularly for the cost variable, which is characterised by markedly skewed distributions. In addition, individual-level data sets are often characterised by the presence of structural zeros in the cost variable. Hurdle models can be used to account for the presence of excess zeros in a distribution and have been applied in the context of cost data. We extend their application to cost-effectiveness data, defining a full Bayesian specification, which consists of a model for the individual probability of null costs, a marginal model for the costs and a conditional model for the measure of effectiveness (given the observed costs). We presented the model using a working example to describe its main features. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd. PMID:24343868

  16. Bayesian models for cost-effectiveness analysis in the presence of structural zero costs.

    PubMed

    Baio, Gianluca

    2014-05-20

    Bayesian modelling for cost-effectiveness data has received much attention in both the health economics and the statistical literature, in recent years. Cost-effectiveness data are characterised by a relatively complex structure of relationships linking a suitable measure of clinical benefit (e.g. quality-adjusted life years) and the associated costs. Simplifying assumptions, such as (bivariate) normality of the underlying distributions, are usually not granted, particularly for the cost variable, which is characterised by markedly skewed distributions. In addition, individual-level data sets are often characterised by the presence of structural zeros in the cost variable. Hurdle models can be used to account for the presence of excess zeros in a distribution and have been applied in the context of cost data. We extend their application to cost-effectiveness data, defining a full Bayesian specification, which consists of a model for the individual probability of null costs, a marginal model for the costs and a conditional model for the measure of effectiveness (given the observed costs). We presented the model using a working example to describe its main features. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd.

  17. Cost-effectiveness Analysis with Influence Diagrams.

    PubMed

    Arias, M; Díez, F J

    2015-01-01

    Cost-effectiveness analysis (CEA) is used increasingly in medicine to determine whether the health benefit of an intervention is worth the economic cost. Decision trees, the standard decision modeling technique for non-temporal domains, can only perform CEA for very small problems. To develop a method for CEA in problems involving several dozen variables. We explain how to build influence diagrams (IDs) that explicitly represent cost and effectiveness. We propose an algorithm for evaluating cost-effectiveness IDs directly, i.e., without expanding an equivalent decision tree. The evaluation of an ID returns a set of intervals for the willingness to pay - separated by cost-effectiveness thresholds - and, for each interval, the cost, the effectiveness, and the optimal intervention. The algorithm that evaluates the ID directly is in general much more efficient than the brute-force method, which is in turn more efficient than the expansion of an equivalent decision tree. Using OpenMarkov, an open-source software tool that implements this algorithm, we have been able to perform CEAs on several IDs whose equivalent decision trees contain millions of branches. IDs can perform CEA on large problems that cannot be analyzed with decision trees.

  18. Impact of pre-application treatment on municipal sludge composition, soil dynamics of antibiotic resistance genes, and abundance of antibiotic-resistance genes on vegetables at harvest.

    PubMed

    Lau, Calvin Ho-Fung; Li, Bing; Zhang, Tong; Tien, Yuan-Ching; Scott, Andrew; Murray, Roger; Sabourin, Lyne; Lapen, David R; Duenk, Peter; Topp, Edward

    2017-06-01

    In many jurisdictions sludge recovered from the sewage treatment process is a valued fertilizer for crop production. Pre-treatment of sewage sludge prior to land application offers the potential to abate enteric microorganisms that carry genes conferring resistance to antibiotics. Pre-treatment practices that accomplish this should have the desirable effect of reducing the risk of contamination of crops or adjacent water with antibiotic resistance genes carried in these materials. In the present study, we obtained municipal sludge that had been subjected to one of five treatments. There were, anaerobic-digestion or aerobic-digestion, in both instances with and without dewatering; and heat-treatment and pelletization. Each of the five types of biosolids was applied to an agricultural field at commercial rates, following which lettuce, carrots and radishes were planted. Based on qPCR, the estimated antibiotic gene loading rates were comparable with each of the five biosolids. However, the gene abundance in soil following application of the pelletized biosolids was anomalously lower than expected. Following application, the abundance of antibiotic resistance genes decreased in a generally coherent fashion, except sul1 which increased in abundance during the growing season in the soil fertilized with pelletized biosolids. Based on qPCR and high throughput sequencing evidence for transfer of antibiotic resistance genes from the biosolids to the vegetables at harvest was weak. Clostridia were more abundant in soils receiving any of the biosolids except the pelletized. Overall, the behavior of antibiotic resistance genes in soils receiving aerobically or anaerobically-digested biosolids was consistent and coherent with previous studies. However, dynamics of antibiotic resistance genes in soils receiving the heat treated pelletized biosolids were very different, and the underlying mechanisms merit investigation. Crown Copyright © 2017. Published by Elsevier B.V. All

  19. Effect of Fertilizer-P application on the relative abundance of nitrogen cycle genes in a phosphorus limited paddy soil from subtropical region

    NASA Astrophysics Data System (ADS)

    Ge, Tida; Wei, Xiaomeng; Wu, Jinshui

    2017-04-01

    The addition of phosphorus to P-limited soils has been shown to cause a marked increase in the loss of gaseous N. The reasons for this remain unclear but linked nutrient cycling in the rhizosphere (C:N:P) leading to enhanced nitrification and denitrification have been proposed. We investigated the impact of adding P to P-limited soils on the dynamics of soil N-cycle functional genes. Rice seedlings were planted in P poor soils and incubated under different water conditions with or without P application. The abundance of ammonia-oxidizing bacteria and archaea in the rhizosphere and bulk soil were quantified by Real Time PCR (qPCR) using amoA gene abundance. Results showed that P addition resulted in a decrease in soil NH4+ content and a reduction in the the abundance of ammonia-oxidizing bacteria (AOB). There was little measurable effect on ammonia-oxidizing archaea (AOA). As expected from the marked increase in gaseous N loss, the relative abundances of the four functional genes (narG nirK, nirS, nosZ) increased following P application. This is thought to be a consequence of reducing the impact of P limitation on denitrifying bacteria in the bulk soil. The experimental design used allowed us to deteremine whether the gene responses to P addition in the rhizosphere (where the molar ratios of C:N:P were expected to differ) were different from those of the bulk soil. This 'rhizosphere effect' was weakened for ammonia oxidizing functional genes and enhanced for denitrifying funcational genes by P application, resulted in a greater abundance of AOB (amoA gene) and lower amounts of nirK, nirS and nosZ in rhizosphere soil. The work reported here shows the impact of available P in regulating gaseous N loss from soil and demonstrates the importance of stoichiometry and balanced nutrient availability on the fertilization and management of agricultural soils.

  20. Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content

    PubMed Central

    Hansen, Thomas; Ismar, Stefanie M. H.; Sommer, Ulrich

    2016-01-01

    Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1–5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts. PMID:27224476

  1. Re-evaluating cost effectiveness of universal meningitis vaccination (Bexsero) in England: modelling study.

    PubMed

    Christensen, Hannah; Trotter, Caroline L; Hickman, Matthew; Edmunds, W John

    2014-10-09

    To use mathematical and economic models to predict the epidemiological and economic impact of vaccination with Bexsero, designed to protect against group B meningococcal disease, to help inform vaccine policy in the United Kingdom. Modelling study. England. People aged 0-99. Incremental impact of introductory vaccine strategies simulated with a transmission dynamic model of meningococcal infection and vaccination including potential herd effects. Model parameters included recent evidence on the vaccine characteristics, disease burden, costs of care, litigation costs, and loss of quality of life from disease, including impacts on family and network members. The health impact of vaccination was assessed through cases averted and quality adjusted life years (QALYs) gained. Cases averted and cost per QALY gained through vaccination; programmes were deemed cost effective against a willingness to pay of £20,000 (€25,420, $32,677) per QALY gained from an NHS and personal and social services perspective. In the short term, case reduction is greatest with routine infant immunisation (26.3% of cases averted in the first five years). This strategy could be cost effective at £3 (€3.8, $4.9) a vaccine dose, given several favourable assumptions and the use of a quality of life adjustment factor. If the vaccine can disrupt meningococcal transmission more cases are prevented in the long term with an infant and adolescent combined programme (51.8% after 30 years), which could be cost effective at £4 a vaccine dose. Assuming the vaccine reduces acquisition by 30%, adolescent vaccination alone is the most favourable strategy economically, but takes more than 20 years to substantially reduce the number of cases. Routine infant vaccination is the most effective short term strategy and could be cost effective with a low vaccine price. Critically, if the vaccine reduces carriage acquisition in teenagers, the combination of infant and adolescent vaccination could result in

  2. Cost and Cost-effectiveness of Students for Nutrition and Exercise (SNaX)

    PubMed Central

    Ladapo, Joseph A.; Bogart, Laura M.; Klein, David J.; Cowgill, Burton O.; Uyeda, Kimberly; Binkle, David G.; Stevens, Elizabeth R.; Schuster, Mark A.

    2015-01-01

    Objective To examine the cost and cost-effectiveness of implementing Students for Nutrition and eXercise (SNaX), a 5-week middle-school-based obesity-prevention intervention combining school-wide environmental changes, multimedia, encouragement to eat healthy school cafeteria foods, and peer-led education. Methods Five intervention and five control middle schools (mean enrollment = 1,520 students) from the Los Angeles Unified School District participated in a randomized controlled trial of SNaX. Acquisition costs for materials and time and wage data for employees involved in implementing the program were used to estimate fixed and variable costs. Cost-effectiveness was determined using the ratio of variable costs to program efficacy outcomes. Results The costs of implementing the program over 5 weeks were $5,433.26 per school in fixed costs and $2.11 per student in variable costs, equaling a total cost of $8,637.17 per school, or $0.23 per student per day. This investment yielded significant increases in the proportion of students served fruit and lunch and a significant decrease in the proportion of students buying snacks. The cost-effectiveness of the program, per student over 5 weeks, was $1.20 per additional fruit served during meals, $8.43 per additional full-priced lunch served, $2.11 per additional reduced-price/free lunch served, and $1.69 per reduction in snacks sold. Conclusions SNaX demonstrated the feasibility and cost-effectiveness of a middle-school-based obesity-prevention intervention combining school-wide environmental changes, multimedia, encouragement to eat healthy school cafeteria foods, and peer-led education. Its cost is modest and unlikely to be a significant barrier to adoption for many schools considering its implementation. PMID:26427719

  3. THE EFFECTS OF INITIAL ABUNDANCES ON NITROGEN IN PROTOPLANETARY DISKS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schwarz, Kamber R.; Bergin, Edwin A.

    2014-12-20

    The dominant form of nitrogen provided to most solar system bodies is currently unknown, though available measurements show that the detected nitrogen in solar system rocks and ices is depleted with respect to solar abundances and the interstellar medium. We use a detailed chemical/physical model of the chemical evolution of a protoplanetary disk to explore the evolution and abundance of nitrogen-bearing molecules. Based on this model, we analyze how initial chemical abundances provided as either gas or ice during the early stages of disk formation influence which species become the dominant nitrogen bearers at later stages. We find that amore » disk with the majority of its initial nitrogen in either atomic or molecular nitrogen is later dominated by atomic and molecular nitrogen as well as NH{sub 3} and HCN ices, where the dominant species varies with disk radius. When nitrogen is initially in gaseous ammonia, it later becomes trapped in ammonia ice except in the outer disk where atomic nitrogen dominates. For a disk with the initial nitrogen in the form of ammonia ice, the nitrogen remains trapped in the ice as NH{sub 3} at later stages. The model in which most of the initial nitrogen is placed in atomic N best matches the ammonia abundances observed in comets. Furthermore, the initial state of nitrogen influences the abundance of N{sub 2}H{sup +}, which has been detected in protoplanetary disks. Strong N{sub 2}H{sup +} emission is found to be indicative of an N{sub 2} abundance greater than n{sub N{sub 2}}/n{sub H{sub 2}}>10{sup −6} in addition to tracing the CO snow line. Our models also indicate that NO is potentially detectable, with lower N gas abundances leading to higher NO abundances.« less

  4. The cost and cost-effectiveness of gender-responsive interventions for HIV: a systematic review

    PubMed Central

    Remme, Michelle; Siapka, Mariana; Vassall, Anna; Heise, Lori; Jacobi, Jantine; Ahumada, Claudia; Gay, Jill; Watts, Charlotte

    2014-01-01

    Introduction Harmful gender norms and inequalities, including gender-based violence, are important structural barriers to effective HIV programming. We assess current evidence on what forms of gender-responsive intervention may enhance the effectiveness of basic HIV programmes and be cost-effective. Methods Effective intervention models were identified from an existing evidence review (“what works for women”). Based on this, we conducted a systematic review of published and grey literature on the costs and cost-effectiveness of each intervention identified. Where possible, we compared incremental costs and effects. Results Our effectiveness search identified 36 publications, reporting on the effectiveness of 22 HIV interventions with a gender focus. Of these, 11 types of interventions had a corresponding/comparable costing or cost-effectiveness study. The findings suggest that couple counselling for the prevention of vertical transmission; gender empowerment, community mobilization, and female condom promotion for female sex workers; expanded female condom distribution for the general population; and post-exposure HIV prophylaxis for rape survivors are cost-effective HIV interventions. Cash transfers for schoolgirls and school support for orphan girls may also be cost-effective in generalized epidemic settings. Conclusions There has been limited research to assess the cost-effectiveness of interventions that seek to address women's needs and transform harmful gender norms. Our review identified several promising, cost-effective interventions that merit consideration as critical enablers in HIV investment approaches, as well as highlight that broader gender and development interventions can have positive HIV impacts. By no means an exhaustive package, these represent a first set of interventions to be included in the investment framework. PMID:25373519

  5. Comparative effectiveness and cost-effectiveness analyses frequently agree on value.

    PubMed

    Glick, Henry A; McElligott, Sean; Pauly, Mark V; Willke, Richard J; Bergquist, Henry; Doshi, Jalpa; Fleisher, Lee A; Kinosian, Bruce; Perfetto, Eleanor; Polsky, Daniel E; Schwartz, J Sanford

    2015-05-01

    The Patient-Centered Outcomes Research Institute, known as PCORI, was established by Congress as part of the Affordable Care Act (ACA) to promote evidence-based treatment. Provisions of the ACA prohibit the use of a cost-effectiveness analysis threshold and quality-adjusted life-years (QALYs) in PCORI comparative effectiveness studies, which has been understood as a prohibition on support for PCORI's conducting conventional cost-effectiveness analyses. This constraint complicates evidence-based choices where incremental improvements in outcomes are achieved at increased costs of care. How frequently this limitation inhibits efficient cost containment, also a goal of the ACA, depends on how often more effective treatment is not cost-effective relative to less effective treatment. We examined the largest database of studies of comparisons of effectiveness and cost-effectiveness to see how often there is disagreement between the more effective treatment and the cost-effective treatment, for various thresholds that may define good value. We found that under the benchmark assumption, disagreement between the two types of analyses occurs in 19 percent of cases. Disagreement is more likely to occur if a treatment intervention is musculoskeletal and less likely to occur if it is surgical or involves secondary prevention, or if the study was funded by a pharmaceutical company. Project HOPE—The People-to-People Health Foundation, Inc.

  6. The effect of peatland drainage and restoration on Odonata species richness and abundance.

    PubMed

    Elo, Merja; Penttinen, Jouni; Kotiaho, Janne S

    2015-04-09

    Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration efforts. Here, we studied how abundance and species richness of Odonata (dragonflies and damselflies) respond to restoration. We sampled larvae in three sites (restored, drained, pristine) on each of 12 different study areas. We sampled Odonata larvae before restoration (n = 12), during the first (n = 10) and the third (n = 7) year after restoration and used generalized linear mixed models to analyze the effect of restoration. Drained sites had lower abundance and species richness than pristine sites. During the third year after restoration both abundance and species richness had risen in restored sites. Our results show that Odonata suffer from drainage, but seem to benefit from peatland restoration and are able to colonize newly formed water pools already within three years after restoration.

  7. Cost-Effectiveness and Cost-Benefit Analysis: Confronting the Problem of Choice.

    ERIC Educational Resources Information Center

    Clardy, Alan

    Cost-effectiveness analysis and cost-benefit analysis are two related yet distinct methods to help decision makers choose the best course of action from among competing alternatives. For both types of analysis, costs are computed similarly. Costs may be reduced to present value amounts for multi-year programs, and parameters may be altered to show…

  8. Spatial and seasonal dynamic of abundance and distribution of guanaco and livestock: insights from using density surface and null models.

    PubMed

    Schroeder, Natalia M; Matteucci, Silvia D; Moreno, Pablo G; Gregorio, Pablo; Ovejero, Ramiro; Taraborelli, Paula; Carmanchahi, Pablo D

    2014-01-01

    Monitoring species abundance and distribution is a prerequisite when assessing species status and population viability, a difficult task to achieve for large herbivores at ecologically meaningful scales. Co-occurrence patterns can be used to infer mechanisms of community organization (such as biotic interactions), although it has been traditionally applied to binary presence/absence data. Here, we combine density surface and null models of abundance data as a novel approach to analyze the spatial and seasonal dynamics of abundance and distribution of guanacos (Lama guanicoe) and domestic herbivores in northern Patagonia, in order to visually and analytically compare the dispersion and co-occurrence pattern of ungulates. We found a marked seasonal pattern in abundance and spatial distribution of L. guanicoe. The guanaco population reached its maximum annual size and spatial dispersion in spring-summer, decreasing up to 6.5 times in size and occupying few sites of the study area in fall-winter. These results are evidence of the seasonal migration process of guanaco populations, an increasingly rare event for terrestrial mammals worldwide. The maximum number of guanacos estimated for spring (25,951) is higher than the total population size (10,000) 20 years ago, probably due to both counting methodology and population growth. Livestock were mostly distributed near human settlements, as expected by the sedentary management practiced by local people. Herbivore distribution was non-random; i.e., guanaco and livestock abundances co-varied negatively in all seasons, more than expected by chance. Segregation degree of guanaco and small-livestock (goats and sheep) was comparatively stronger than that of guanaco and large-livestock, suggesting a competition mechanism between ecologically similar herbivores, although various environmental factors could also contribute to habitat segregation. The new and compelling combination of methods used here is highly useful for

  9. Hospital pharmacy decisions, cost containment, and the use of cost-effectiveness analysis.

    PubMed

    Sloan, F A; Whetten-Goldstein, K; Wilson, A

    1997-08-01

    The key hypothesis of the study was that hospital pharmacies under the pressure of managed care would be more likely to adopt process innovations to assure less costly and more cost-effective provision of care. We conducted a survey of 103 hospitals and analyzed secondary data on cost and staffing. Compared to the size of the reduction in length of stay, changes in the way that a day of care is delivered appear to be minor, even in areas with substantial managed care share. The vast majority of hospitals surveyed had implemented some form of therapeutic interchange and generic substitution. Most hospitals used some drug utilization guidelines, but as of mid 1995 these were not yet important management tools for hospital pharmacies. To our knowledge, ours was the first survey to investigate the link between hospital formularies and use of cost-effectiveness analysis. At most cost-effectiveness was a minor tool in pharmaceutical decision making in hospitals at present. We could determine no differences in use of such analyses by managed care market share in the hospital's market share. One impediment to the use of cost-effectiveness studies was the lack of timeliness of studies. Other stated reasons for not using cost-effectiveness analysis more often were: lack of information on hospitalized patients and hence on the potential cost offsets accruing to the hospital: lack of independent sponsorship, and inadequate expertise in economic evaluation.

  10. The cost-effectiveness of life-saving interventions in Japan. Do chemical regulations cost too much?

    PubMed

    Kishimoto, Atsuo; Oka, Tosihiro; Nakanishi, Junko

    2003-10-01

    This paper compares the cost-effectiveness of life-saving interventions in Japan, based on information collected from the health, safety and environmental literature. More than 50 life-saving interventions are analyzed. Cost-effectiveness is defined as the cost per life-year saved or as the cost per quality-adjusted life-year saved. Finding a large cost-effectiveness disparity between chemical controls and health care intervention, we raise the question of whether chemical regulations cost society too much. We point out the limitations of this study and propose a way to improve the incorporation of morbidity effects in cost-effectiveness analysis.

  11. Linking quality of care and training costs: cost-effectiveness in health professions education.

    PubMed

    Tolsgaard, Martin G; Tabor, Ann; Madsen, Mette E; Wulff, Camilla B; Dyre, Liv; Ringsted, Charlotte; Nørgaard, Lone N

    2015-12-01

    To provide a model for conducting cost-effectiveness analyses in medical education. The model was based on a randomised trial examining the effects of training midwives to perform cervical length measurement (CLM) as compared with obstetricians on patients' waiting times. (CLM), as compared with obstetricians. The model included four steps: (i) gathering data on training outcomes, (ii) assessing total costs and effects, (iii) calculating the incremental cost-effectiveness ratio (ICER) and (iv) estimating cost-effectiveness probability for different willingness to pay (WTP) values. To provide a model example, we conducted a randomised cost-effectiveness trial. Midwives were randomised to CLM training (midwife-performed CLMs) or no training (initial management by midwife, and CLM performed by obstetrician). Intervention-group participants underwent simulation-based and clinical training until they were proficient. During the following 6 months, waiting times from arrival to admission or discharge were recorded for women who presented with symptoms of pre-term labour. Outcomes for women managed by intervention and control-group participants were compared. These data were then used for the remaining steps of the cost-effectiveness model. Intervention-group participants needed a mean 268.2 (95% confidence interval [CI], 140.2-392.2) minutes of simulator training and a mean 7.3 (95% CI, 4.4-10.3) supervised scans to attain proficiency. Women who were scanned by intervention-group participants had significantly reduced waiting time compared with those managed by the control group (n = 65; mean difference, 36.6 [95% CI 7.3-65.8] minutes; p = 0.008), which corresponded to an ICER of 0.45 EUR minute(-1) . For WTP values less than EUR 0.26 minute(-1) , obstetrician-performed CLM was the most cost-effective strategy, whereas midwife-performed CLM was cost-effective for WTP values above EUR 0.73 minute(-1) . Cost-effectiveness models can be used to link quality of care to

  12. The cost-effectiveness of NBPTS teacher certification.

    PubMed

    Yeh, Stuart S

    2010-06-01

    A cost-effectiveness analysis of the National Board for Professional Teaching Standards (NBPTS) program suggests that Board certification is less cost-effective than a range of alternative approaches for raising student achievement, including comprehensive school reform, class size reduction, a 10% increase in per pupil expenditure, the use of value-added statistical methods to identify effective teachers, and the implementation of systems where student performance in math and reading is rapidly assessed 2-5 times per week. The most cost-effective approach, rapid assessment, is three magnitudes as cost-effective as Board certification.

  13. On the patterns of abundance and diversity of macrolichens of Chopta-Tunganath in the Garhwal Himalaya.

    PubMed

    Negi, H R

    2000-12-01

    A total of 3211 colonies of macrolichens, from twelve 50 m x 10 m plots distributed across four macrohabitat (vegetation) types between 1500 m-3700 m in the Chopta-Tunganath landscape of the Garhwal Himalaya, yielded 13 families with 15 genera and 85 species. Lobaria retigera stood out as a broad-niched generalist species with moderate levels of abundance in all the three major microhabitats, viz. rock, soil and wood across 83% of all the plots sampled, whereas Umbilicaria indica emerged as an abundantly occurring specialist confined to rock substrates. Heterodermia incana and Leptogium javanicum appeared to be rare members of the community as they were encountered only once during the field survey. Woody microhabitats turned out to be richer than rock and soil substrates for macrolichens. Amongst the macrohabitats, middle altitude (2500-2800 m) Quercus forest was richest in species and genera followed by high altitude (2900-3200 m) Rhododendron forest, higher altitude grasslands (3300-3700 m) and then the lower elevation (1500 m) Quercus forest. Species, genus and family level alpha- as well as beta-diversities were significantly correlated with each other, implying that higher taxonomic ranks such as genera may be used as surrogates for species thus facilitating cost- and time-effective periodic monitoring of the biodiversity of macrolichens. Dynamics of the diversity of lichen communities in relation to various forms of environmental disturbance including livestock grazing and tourism as dominant land use activities in the higher Himalaya need further research.

  14. When is critical care medicine cost-effective? A systematic review of the cost-effectiveness literature.

    PubMed

    Talmor, Daniel; Shapiro, Nathan; Greenberg, Dan; Stone, Patricia W; Neumann, Peter J

    2006-11-01

    Receiving care in an intensive care unit can greatly influence patients' survival and quality of life. Such treatments can, however, be extremely resource intensive. Therefore, it is increasingly important to understand the costs and consequences associated with interventions aimed at reducing mortality and morbidity of critically ill patients. Cost-effectiveness analyses (CEAs) have become increasingly common to aid decisions about the allocation of scarce healthcare resources. To identify published original CEAs presenting cost/quality-adjusted life year or cost/life-year ratios for treatments used in intensive care units, to summarize the results in an accessible format, and to identify areas in critical care medicine that merit further economic evaluation. We conducted a systematic search of the English-language literature for original CEAs of critical care interventions published from 1993 through 2003. We collected data on the target population, therapy or program, study results, analytic methods employed, and the cost-effectiveness ratios presented. We identified 19 CEAs published through 2003 with 48 cost-effectiveness ratios pertaining to treatment of severe sepsis, acute respiratory failure, and general critical care interventions. These ratios ranged from cost saving to 958,423 US dollars/quality-adjusted life year and from 1,150 to 575,054 US dollars/life year gained. Many studies reported favorable cost-effectiveness profiles (i.e., below 50,000 US dollars/life year or quality-adjusted life year). Specific interventions such as activated protein C for patients with severe sepsis have been shown to provide good value for money. However, overall there is a paucity of CEA literature on the management of the critically ill, and further high-quality CEA is needed. In particular, research should focus on costly interventions such as 24-hr intensivist availability, early goal-directed therapy, and renal replacement therapy. Recent guidelines for the conduct

  15. The cost of preventing undernutrition: cost, cost-efficiency and cost-effectiveness of three cash-based interventions on nutrition outcomes in Dadu, Pakistan.

    PubMed

    Trenouth, Lani; Colbourn, Timothy; Fenn, Bridget; Pietzsch, Silke; Myatt, Mark; Puett, Chloe

    2018-07-01

    Cash-based interventions (CBIs) increasingly are being used to deliver humanitarian assistance and there is growing interest in the cost-effectiveness of cash transfers for preventing undernutrition in emergency contexts. The objectives of this study were to assess the costs, cost-efficiency and cost-effectiveness in achieving nutrition outcomes of three CBIs in southern Pakistan: a 'double cash' (DC) transfer, a 'standard cash' (SC) transfer and a 'fresh food voucher' (FFV) transfer. Cash and FFVs were provided to poor households with children aged 6-48 months for 6 months in 2015. The SC and FFV interventions provided $14 monthly and the DC provided $28 monthly. Cost data were collected via institutional accounting records, interviews, programme observation, document review and household survey. Cost-effectiveness was assessed as cost per case of wasting, stunting and disability-adjusted life year (DALY) averted. Beneficiary costs were higher for the cash groups than the voucher group. Net total cost transfer ratios (TCTRs) were estimated as 1.82 for DC, 2.82 for SC and 2.73 for FFV. Yet, despite the higher operational costs, the FFV TCTR was lower than the SC TCTR when incorporating the participation cost to households, demonstrating the relevance of including beneficiary costs in cost-efficiency estimations. The DC intervention achieved a reduction in wasting, at $4865 per case averted; neither the SC nor the FFV interventions reduced wasting. The cost per case of stunting averted was $1290 for DC, $882 for SC and $883 for FFV. The cost per DALY averted was $641 for DC, $434 for SC and $563 for FFV without discounting or age weighting. These interventions are highly cost-effective by international thresholds. While it is debatable whether these resource requirements represent a feasible or sustainable investment given low health expenditures in Pakistan, these findings may provide justification for continuing Pakistan's investment in national social safety

  16. Experimental Beetle Metapopulations Respond Positively to Dynamic Landscapes and Reduced Connectivity

    PubMed Central

    Govindan, Byju N.; Swihart, Robert K.

    2012-01-01

    Interactive effects of multiple environmental factors on metapopulation dynamics have received scant attention. We designed a laboratory study to test hypotheses regarding interactive effects of factors affecting the metapopulation dynamics of red flour beetle, Tribolium castaneum. Within a four-patch landscape we modified resource level (constant and diminishing), patch connectivity (high and low) and patch configuration (static and dynamic) to conduct a 23 factorial experiment, consisting of 8 metapopulations, each with 3 replicates. For comparison, two control populations consisting of isolated and static subpopulations were provided with resources at constant or diminishing levels. Longitudinal data from 22 tri-weekly counts of beetle abundance were analyzed using Bayesian Poisson generalized linear mixed models to estimate additive and interactive effects of factors affecting abundance. Constant resource levels, low connectivity and dynamic patches yielded greater levels of adult beetle abundance. For a given resource level, frequency of colonization exceeded extinction in landscapes with dynamic patches when connectivity was low, thereby promoting greater patch occupancy. Negative density dependence of pupae on adults occurred and was stronger in landscapes with low connectivity and constant resources; these metapopulations also demonstrated greatest stability. Metapopulations in control landscapes went extinct quickly, denoting lower persistence than comparable landscapes with low connectivity. When landscape carrying capacity was constant, habitat destruction coupled with low connectivity created asynchronous local dynamics and refugia within which cannibalism of pupae was reduced. Increasing connectivity may be counter-productive and habitat destruction/recreation may be beneficial to species in some contexts. PMID:22509314

  17. Is the societal approach wide enough to include relatives? Incorporating relatives' costs and effects in a cost-effectiveness analysis.

    PubMed

    Davidson, Thomas; Levin, Lars-Ake

    2010-01-01

    It is important for economic evaluations in healthcare to cover all relevant information. However, many existing evaluations fall short of this goal, as they fail to include all the costs and effects for the relatives of a disabled or sick individual. The objective of this study was to analyse how relatives' costs and effects could be measured, valued and incorporated into a cost-effectiveness analysis. In this article, we discuss the theories underlying cost-effectiveness analyses in the healthcare arena; the general conclusion is that it is hard to find theoretical arguments for excluding relatives' costs and effects if a societal perspective is used. We argue that the cost of informal care should be calculated according to the opportunity cost method. To capture relatives' effects, we construct a new term, the R-QALY weight, which is defined as the effect on relatives' QALY weight of being related to a disabled or sick individual. We examine methods for measuring, valuing and incorporating the R-QALY weights. One suggested method is to estimate R-QALYs and incorporate them together with the patient's QALY in the analysis. However, there is no well established method as yet that can create R-QALY weights. One difficulty with measuring R-QALY weights using existing instruments is that these instruments are rarely focused on relative-related aspects. Even if generic quality-of-life instruments do cover some aspects relevant to relatives and caregivers, they may miss important aspects and potential altruistic preferences. A further development and validation of the existing caregiving instruments used for eliciting utility weights would therefore be beneficial for this area, as would further studies on the use of time trade-off or Standard Gamble methods for valuing R-QALY weights. Another potential method is to use the contingent valuation method to find a monetary value for all the relatives' costs and effects. Because cost-effectiveness analyses are used for

  18. Is robotic surgery cost-effective: yes.

    PubMed

    Liberman, Daniel; Trinh, Quoc-Dien; Jeldres, Claudio; Zorn, Kevin C

    2012-01-01

    With the expanding use of new technology in the treatment of clinically localized prostate cancer (PCa), the financial burden on the healthcare system and the individual has been important. Robotics offer many potential advantages to the surgeon and the patient. We assessed the potential cost-effectiveness of robotics in urological surgery and performed a comparative cost analysis with respect to other potential treatment modalities. The direct and indirect costs of purchasing, maintaining, and operating the robot must be compared to alternatives in treatment of localized PCa. Some expanding technologies including intensity-modulated radiation therapy are significantly more expensive than robotic surgery. Furthermore, the benefits of robotics including decreased length of stay and return to work are considerable and must be measured when evaluating its cost-effectiveness. Robot-assisted laparoscopic surgery comes at a high cost but can become cost-effective in mostly high-volume centers with high-volume surgeons. The device when utilized to its maximum potential and with eventual market-driven competition can become affordable.

  19. Forest bat population dynamics over 14 years at a climate refuge: Effects of timber harvesting and weather extremes

    PubMed Central

    Chidel, Mark; Law, Peter R.

    2018-01-01

    Long-term data are needed to explore the interaction of weather extremes with habitat alteration; in particular, can ‘refugia’ buffer population dynamics against climate change and are they robust to disturbances such as timber harvesting. Because forest bats are good indicators of ecosystem health, we used 14 years (1999–2012) of mark-recapture data from a suite of small tree-hollow roosting bats to estimate survival, abundance and body condition in harvested and unharvested forest and over extreme El Niño and La Niña weather events in southeastern Australia. Trapping was replicated within an experimental forest, located in a climate refuge, with different timber harvesting treatments. We trapped foraging bats and banded 3043 with a 32% retrap rate. Mark-recapture analyses allowed for dependence of survival on time, species, sex, logging treatment and for transients. A large portion of the population remained resident, with a maximum time to recapture of nine years. The effect of logging history (unlogged vs 16–30 years post-logging regrowth) on apparent survival was minor and species specific, with no detectable effect for two species, a positive effect for one and negative for the other. There was no effect of logging history on abundance or body condition for any of these species. Apparent survival of residents was not strongly influenced by weather variation (except for the smallest species), unlike previous studies outside of refugia. Despite annual variation in abundance and body condition across the 14 years of the study, no relationship with extreme weather was evident. The location of our study area in a climate refuge potentially buffered bat population dynamics from extreme weather. These results support the value of climate refugia in mitigating climate change impacts, though the lack of an external control highlights the need for further studies on the functioning of climate refugia. Relatively stable population dynamics were not compromised

  20. Forest bat population dynamics over 14 years at a climate refuge: Effects of timber harvesting and weather extremes.

    PubMed

    Law, Bradley S; Chidel, Mark; Law, Peter R

    2018-01-01

    Long-term data are needed to explore the interaction of weather extremes with habitat alteration; in particular, can 'refugia' buffer population dynamics against climate change and are they robust to disturbances such as timber harvesting. Because forest bats are good indicators of ecosystem health, we used 14 years (1999-2012) of mark-recapture data from a suite of small tree-hollow roosting bats to estimate survival, abundance and body condition in harvested and unharvested forest and over extreme El Niño and La Niña weather events in southeastern Australia. Trapping was replicated within an experimental forest, located in a climate refuge, with different timber harvesting treatments. We trapped foraging bats and banded 3043 with a 32% retrap rate. Mark-recapture analyses allowed for dependence of survival on time, species, sex, logging treatment and for transients. A large portion of the population remained resident, with a maximum time to recapture of nine years. The effect of logging history (unlogged vs 16-30 years post-logging regrowth) on apparent survival was minor and species specific, with no detectable effect for two species, a positive effect for one and negative for the other. There was no effect of logging history on abundance or body condition for any of these species. Apparent survival of residents was not strongly influenced by weather variation (except for the smallest species), unlike previous studies outside of refugia. Despite annual variation in abundance and body condition across the 14 years of the study, no relationship with extreme weather was evident. The location of our study area in a climate refuge potentially buffered bat population dynamics from extreme weather. These results support the value of climate refugia in mitigating climate change impacts, though the lack of an external control highlights the need for further studies on the functioning of climate refugia. Relatively stable population dynamics were not compromised by

  1. Position Estimation for Projectiles Using Low-cost Sensors and Flight Dynamics

    DTIC Science & Technology

    2012-04-01

    GPS/INS Loose-coupling Parameter Estimation ............................................................6 2.6 Extended Kalman Filter ...environment using low-cost measurement devices and projectile flight dynamics. An extended Kalman filter (EKF) was developed to blend accelerometer...kGPSIbias B GPSIkGPSIbias B GPSIGPSIbias B aρaρa ,,1,,, 1    (15) 7 2.6 Extended Kalman Filter A sequential EKF was used to combine

  2. Cost-effectiveness and the socialization of health care.

    PubMed

    Musgrove, P

    1995-01-01

    The more health care is socialized, the more cost-effectiveness is an appropriate criterion for expenditure. Utility-maximizing individuals, facing divisibility of health care purchases and declining marginal health gains, and complete information about probable health improvements, should buy health care according to its cost-effectiveness. Absent these features, individual health spending will not be cost-effective; and in any case, differences in personal utilities and risk aversion will not lead to the same ranking of health care interventions for everyone. Private insurance frees consumers from concern for cost, which undermines cost-effectiveness, but lets them emphasize effectiveness, which favors value for money. This is most important for costly and cost-effective interventions, especially for poor people. Cost-effectiveness is more appropriate and easier to achieve under second-party insurance. More complete socialization of health care, via public finance, can yield greater efficiency by making insurance compulsory. Cost-effectiveness is also more attractive when taxpayers subsidize others' care: needs (effectiveness) take precedence over wants (utility). The gain in effectiveness may be greater, and the welfare loss from Pareto non-optimality smaller, in poor countries than in rich ones.

  3. The comparative effectiveness and cost-effectiveness of vitreoretinal interventions.

    PubMed

    Brown, Melissa M; Brown, Gary C; Brown, Heidi C; Irwin, Blair; Brown, Kathryn S

    2008-05-01

    The comparative effectiveness of medical interventions has recently been emphasized in the literature, typically for interventions in a similar class. Value-based medicine, the practice of medicine based on the value (improvement in quality of life and/or length of life) conferred by medical interventions, allows a measure of comparative effectiveness of interventions across all of health care, no matter how disparate. This report discusses recent comparative effectiveness studies in the vitreoretinal literature. Vitreoretinal interventions have good to excellent comparative effectiveness compared with commonly utilized interventions across health care, such as treatment for osteoporosis and hyperlipidemia. They also tend to be cost-effective when an upper limit of $100 000/quality-adjusted life-year is utilized. Value can be measured using either or both of two outcomes - the quality-adjusted life-year gain and/or the percentage improvement in value - both of which allow for an evaluation of comparative effectiveness, which can be compared on the same scale for every intervention. This value can also be integrated with costs using the outcome of dollars expended per quality-adjusted life-year ($/quality-adjusted life-year, or the cost-utility ratio), which allows a comparison of cost-effectiveness across all interventions. The majority of vitreoretinal interventions confer considerable value and are cost-effective.

  4. Cross-correlation map analyses show weather variation influences on mosquito abundance patterns in Saginaw County, Michigan, 1989-2005.

    PubMed

    Chuang, Ting-Wu; Ionides, Edward L; Knepper, Randall G; Stanuszek, William W; Walker, Edward D; Wilson, Mark L

    2012-07-01

    Weather is important determinant of mosquito abundance that, in turn, influences vectorborne disease dynamics. In temperate regions, transmission generally is seasonal as mosquito abundance and behavior varies with temperature, precipitation, and other meteorological factors. We investigated how such factors affected species-specific mosquito abundance patterns in Saginaw County, MI, during a 17-yr period. Systematic sampling was undertaken at 22 trapping sites from May to September, during 1989-2005, for 19,228 trap-nights and 300,770 mosquitoes in total. Aedes vexans (Meigen), Culex pipiens L. and Culex restuans Theobald, the most abundant species, were analyzed. Weather data included local daily maximum temperature, minimum temperature, total precipitation, and average relative humidity. In addition to standard statistical methods, cross-correlation mapping was used to evaluate temporal associations with various lag periods between weather variables and species-specific mosquito abundances. Overall, the average number of mosquitoes was 4.90 per trap-night for Ae. vexans, 2.12 for Cx. pipiens, and 1.23 for Cx. restuans. Statistical analysis of the considerable temporal variability in species-specific abundances indicated that precipitation and relative humidity 1 wk prior were significantly positively associated with Ae. vexans, whereas elevated maximum temperature had a negative effect during summer. Cx. pipiens abundance was positively influenced by the preceding minimum temperature in the early season but negatively associated with precipitation during summer and with maximum temperature in July and August. Cx. restuans showed the least weather association, with only relative humidity 2-24 d prior being linked positively during late spring-early summer. The recently developed analytical method applied in this study could enhance our understanding of the influences of weather variability on mosquito population dynamics.

  5. Cost-effectiveness of rotavirus vaccination in Albania.

    PubMed

    Ahmeti, Albana; Preza, Iria; Simaku, Artan; Nelaj, Erida; Clark, Andrew David; Felix Garcia, Ana Gabriela; Lara, Carlos; Hoestlandt, Céline; Blau, Julia; Bino, Silvia

    2015-05-07

    Rotavirus vaccines have been introduced in several European countries but can represent a considerable cost, particularly for countries that do not qualify for any external financial support. This study aimed to evaluate the cost-effectiveness of introducing rotavirus vaccination into Albania's national immunization program and to inform national decision-making by improving national capacity to conduct economic evaluations of new vaccines. The TRIVAC model was used to assess vaccine impact and cost-effectiveness. The model estimated health and economic outcomes attributed to 10 successive vaccinated birth cohorts (2013-2022) from a government and societal perspective. Epidemiological and economic data used in the model were based on national cost studies, and surveillance data, as well as estimates from the scientific literature. Cost-effectiveness was estimated for both the monovalent (RV1) and pentavalent vaccines (RV5). A multivariate scenario analysis (SA) was performed to evaluate the uncertainty around the incremental cost-effectiveness ratios (ICERs). With 3% discounting of costs and health benefits over the period 2013-2022, rotavirus vaccination in Albania could avert 51,172 outpatient visits, 14,200 hospitalizations, 27 deaths, 950 disability-adjusted life-years (DALYs), and gain 801 life-years. When both vaccines were compared to no vaccination, the discounted cost per DALY averted was US$ 2008 for RV1 and US$ 5047 for RV5 from a government perspective. From the societal perspective the values were US$ 517 and US$ 3556, respectively. From both the perspectives, the introduction of rotavirus vaccine to the Albanian immunization schedule is either cost-effective or highly cost-effective for a range of plausible scenarios. In most scenarios, including the base-case scenario, the discounted cost per DALY averted was less than three times the gross domestic product (GDP) per capita. However, rotavirus vaccination was not cost-effective when rotavirus cases

  6. Models of Experimentally Derived Competitive Effects Predict Biogeographical Differences in the Abundance of Invasive and Native Plant Species

    PubMed Central

    Xiao, Sa; Ni, Guangyan; Callaway, Ragan M.

    2013-01-01

    Mono-dominance by invasive species provides opportunities to explore determinants of plant distributions and abundance; however, linking mechanistic results from small scale experiments to patterns in nature is difficult. We used experimentally derived competitive effects of an invader in North America, Acroptilon repens, on species with which it co-occurs in its native range of Uzbekistan and on species with which it occurs in its non-native ranges in North America, in individual-based models. We found that competitive effects yielded relative abundances of Acroptilon and other species in models that were qualitatively similar to those observed in the field in the two ranges. In its non-native range, Acroptilon can occur in nearly pure monocultures at local scales, whereas such nearly pure stands of Acroptilon appear to be much less common in its native range. Experimentally derived competitive effects of Acroptilon on other species predicted Acroptilon to be 4–9 times more proportionally abundant than natives in the North American models, but proportionally equal to or less than the abundance of natives in the Eurasian models. Our results suggest a novel way to integrate complex combinations of interactions simultaneously, and that biogeographical differences in the competitive effects of an invader correspond well with biogeographical differences in abundance and impact. PMID:24265701

  7. Cost-effectiveness of monitoring free flaps.

    PubMed

    Subramaniam, Shiva; Sharp, David; Jardim, Christopher; Batstone, Martin D

    2016-06-01

    Methods of free flap monitoring have become more sophisticated and expensive. This study aims to determine the cost of free flap monitoring and examine its cost effectiveness. We examined a group of patients who had had free flaps to the head and neck over a two-year period, and combined these results with costs obtained from business managers and staff. There were 132 free flaps with a success rate of 99%. The cost of monitoring was Aus $193/flap. Clinical monitoring during this time period cost Aus$25 476 and did not lead to the salvage of any free flaps. Cost equivalence is reached between monitoring and not monitoring only at a failure rate of 15.8%. This is to our knowledge the first study to calculate the cost of clinical monitoring of free flaps, and to examine its cost-effectiveness. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. All rights reserved.

  8. Cost-effectiveness of root caries preventive treatments.

    PubMed

    Schwendicke, Falk; Göstemeyer, Gerd

    2017-01-01

    With a growing number of individuals retaining their teeth lifelong, often with periodontitis-induced root surface exposure, there is the need for cost-effective management strategies for root caries lesions. The present study aimed to assess the cost-effectiveness of root caries preventive treatments. Patients were simulated over 10 years using a Markov model. Four treatments were compared: No treatment, daily 225-800ppm fluoride rinses, chlorhexidine (CHX) varnish (2×/year), silver diamine fluoride (SDF) varnish (2×/year). Data from a systematic review were submitted to network meta-analysis for inferring relative efficacies of treatments. The health outcome was years of teeth being free of root caries. A mixed public-private payer perspective within 2016 German healthcare was taken, with costs being estimated from fee item catalogues or based on market prices. Populations with different numbers of teeth and tooth-level risks were modelled. Monte-Carlo microsimulations, univariate- and probabilistic sensitivity analyses were performed. In populations with 16 teeth at risk and low tooth-level risk for root caries, providing no preventive treatment was least costly, but also least effective (130 Euro, 144 years). SDF ranked next, being more costly (180 Euro), but also more effective (151 years). Payers willing to invest 8.30 Euro per root caries-free tooth-year found SDF most cost-effective. CHX varnish and fluoride rinse were not cost-effective. In populations with more teeth and high tooth-level risk, SDF was the most effective and least costly option. Root caries preventive treatments (like SDF) are effective and might even be cost-saving in high risk populations. Application of SDF can be recommended as a cost-saving treatment for prevention of root caries in patients with high risk of root caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Toward cost-effective solar energy use.

    PubMed

    Lewis, Nathan S

    2007-02-09

    At present, solar energy conversion technologies face cost and scalability hurdles in the technologies required for a complete energy system. To provide a truly widespread primary energy source, solar energy must be captured, converted, and stored in a cost-effective fashion. New developments in nanotechnology, biotechnology, and the materials and physical sciences may enable step-change approaches to cost-effective, globally scalable systems for solar energy use.

  10. Effects of effluent water on the abundance of cowpea insect pests.

    PubMed

    Tiroesele, Bamphitlhi; Sitwane, Monametsi; Obopile, M; Ullah, Muhammad Irfan; Ali, Sajjad

    2017-10-03

    Botswana experiences low and unreliable rainfall. Thus, the use of effluent water in agriculture is increasingly important. Insect damage is the major constraint for cowpea grain production in the most cowpea-producing lands. We investigated the effects of effluent water on insect pest abundance on cowpea (Vigna unguiculata) under field conditions. The experiment was laid out in a randomized complete block design with 100, 75, 50, and 25% of effluent water and 0% (control-clean tap water) treatments. Treatments with 100% effluent water resulted in a significant increase in insect pest populations as compared with the control. These results show that the use of effluent water to irrigate crops may increase incidence, abundance, and damage caused by insect pests possibly by decreasing plant vigor. The use of effluent water in agriculture should be addressed in a wise way.

  11. OXYGEN ABUNDANCES IN CEPHEIDS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Luck, R. E.; Andrievsky, S. M.; Korotin, S. N.

    2013-07-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTEmore » analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.« less

  12. The cost and management of different types of clinical mastitis in dairy cows estimated by dynamic programming.

    PubMed

    Cha, E; Bar, D; Hertl, J A; Tauer, L W; Bennett, G; González, R N; Schukken, Y H; Welcome, F L; Gröhn, Y T

    2011-09-01

    The objective of this study was to estimate the cost of 3 different types of clinical mastitis (CM) (caused by gram-positive bacteria, gram-negative bacteria, and other organisms) at the individual cow level and thereby identify the economically optimal management decision for each type of mastitis. We made modifications to an existing dynamic optimization and simulation model, studying the effects of various factors (incidence of CM, milk loss, pregnancy rate, and treatment cost) on the cost of different types of CM. The average costs per case (US$) of gram-positive, gram-negative, and other CM were $133.73, $211.03, and $95.31, respectively. This model provided a more informed decision-making process in CM management for optimal economic profitability and determined that 93.1% of gram-positive CM cases, 93.1% of gram-negative CM cases, and 94.6% of other CM cases should be treated. The main contributor to the total cost per case was treatment cost for gram-positive CM (51.5% of the total cost per case), milk loss for gram-negative CM (72.4%), and treatment cost for other CM (49.2%). The model affords versatility as it allows for parameters such as production costs, economic values, and disease frequencies to be altered. Therefore, cost estimates are the direct outcome of the farm-specific parameters entered into the model. Thus, this model can provide farmers economically optimal guidelines specific to their individual cows suffering from different types of CM. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Cost-effectiveness of screening for HIV in primary care: a health economics modelling analysis.

    PubMed

    Baggaley, Rebecca F; Irvine, Michael A; Leber, Werner; Cambiano, Valentina; Figueroa, Jose; McMullen, Heather; Anderson, Jane; Santos, Andreia C; Terris-Prestholt, Fern; Miners, Alec; Hollingsworth, T Déirdre; Griffiths, Chris J

    2017-10-01

    Early HIV diagnosis reduces morbidity, mortality, the probability of onward transmission, and their associated costs, but might increase cost because of earlier initiation of antiretroviral treatment (ART). We investigated this trade-off by estimating the cost-effectiveness of HIV screening in primary care. We modelled the effect of the four-times higher diagnosis rate observed in the intervention arm of the RHIVA2 randomised controlled trial done in Hackney, London (UK), a borough with high HIV prevalence (≥0·2% adult prevalence). We constructed a dynamic, compartmental model representing incidence of infection and the effect of screening for HIV in general practices in Hackney. We assessed cost-effectiveness of the RHIVA2 trial by fitting model diagnosis rates to the trial data, parameterising with epidemiological and behavioural data from the literature when required, using trial testing costs and projecting future costs of treatment. Over a 40 year time horizon, incremental cost-effectiveness ratios were £22 201 (95% credible interval 12 662-132 452) per quality-adjusted life-year (QALY) gained, £372 207 (268 162-1 903 385) per death averted, and £628 874 (434 902-4 740 724) per HIV transmission averted. Under this model scenario, with UK cost data, RHIVA2 would reach the upper National Institute for Health and Care Excellence cost-effectiveness threshold (about £30 000 per QALY gained) after 33 years. Scenarios using cost data from Canada (which indicate prolonged and even higher health-care costs for patients diagnosed late) suggest this threshold could be reached in as little as 13 years. Screening for HIV in primary care has important public health benefits as well as clinical benefits. We predict it to be cost-effective in the UK in the medium term. However, this intervention might be cost-effective far sooner, and even cost-saving, in settings where long-term health-care costs of late-diagnosed patients in high

  14. Effect of cattle exclosures on Columbia Spotted Frog abundance

    USGS Publications Warehouse

    Adams, Michael J.; Pearl, Christopher; Chambert, Thierry; Mccreary, Brome; Galvan, Stephanie; Rowe, Jennifer

    2018-01-01

    Livestock grazing is an important land use in the western USA and can have positive or negative effects on amphibians. Columbia Spotted Frog (Rana luteiventris) often use ponds that provide water for cattle. We conducted a long-term manipulative study on US Forest Service land in northeastern Oregon to determine the effects of full and partial exclosures that limited cattle access to ponds used by frogs. We found weak evidence of a short-term increase in abundance that did not differ between full and partial exclosures and that diminished with continuing exclusion of cattle. The benefit of exclosures was small relative to the overall decline in breeding numbers that we documented. This suggests that some protection can provide a short-term boost to populations.

  15. Scaling up integrated prevention campaigns for global health: costs and cost-effectiveness in 70 countries

    PubMed Central

    Marseille, Elliot; Jiwani, Aliya; Raut, Abhishek; Verguet, Stéphane; Walson, Judd; Kahn, James G

    2014-01-01

    Objective This study estimated the health impact, cost and cost-effectiveness of an integrated prevention campaign (IPC) focused on diarrhoea, malaria and HIV in 70 countries ranked by per capita disability-adjusted life-year (DALY) burden for the three diseases. Methods We constructed a deterministic cost-effectiveness model portraying an IPC combining counselling and testing, cotrimoxazole prophylaxis, referral to treatment and condom distribution for HIV prevention; bed nets for malaria prevention; and provision of household water filters for diarrhoea prevention. We developed a mix of empirical and modelled cost and health impact estimates applied to all 70 countries. One-way, multiway and scenario sensitivity analyses were conducted to document the strength of our findings. We used a healthcare payer's perspective, discounted costs and DALYs at 3% per year and denominated cost in 2012 US dollars. Primary and secondary outcomes The primary outcome was cost-effectiveness expressed as net cost per DALY averted. Other outcomes included cost of the IPC; net IPC costs adjusted for averted and additional medical costs and DALYs averted. Results Implementation of the IPC in the 10 most cost-effective countries at 15% population coverage would cost US$583 million over 3 years (adjusted costs of US$398 million), averting 8.0 million DALYs. Extending IPC programmes to all 70 of the identified high-burden countries at 15% coverage would cost an adjusted US$51.3 billion and avert 78.7 million DALYs. Incremental cost-effectiveness ranged from US$49 per DALY averted for the 10 countries with the most favourable cost-effectiveness to US$119, US$181, US$335, US$1692 and US$8340 per DALY averted as each successive group of 10 countries is added ordered by decreasing cost-effectiveness. Conclusions IPC appears cost-effective in many settings, and has the potential to substantially reduce the burden of disease in resource-poor countries. This study increases confidence that IPC

  16. Abundance, survival, recruitment and effectiveness of sterilization of free-roaming dogs: A capture and recapture study in Brazil

    PubMed Central

    Struchiner, Claudio José; Werneck, Guilherme Loureiro; Teixeira Neto, Rafael Gonçalves; Tonelli, Gabriel Barbosa; de Carvalho Júnior, Clóvis Gomes; Ribeiro, Renata Aparecida Nascimento; da Silva, Eduardo Sérgio

    2017-01-01

    The existence of free-roaming dogs raises important issues in animal welfare and in public health. A proper understanding of these animals’ ecology is useful as a necessary input to plan strategies to control these populations. The present study addresses the population dynamics and the effectiveness of the sterilization of unrestricted dogs using capture and recapture procedures suitable for open animal populations. Every two months, over a period of 14 months, we captured, tagged, released and recaptured dogs in two regions in a city in the southeast region of Brazil. In one of these regions the animals were also sterilized. Both regions had similar social, environmental and demographic features. We estimated the presence of 148 females and 227 males during the period of study. The average dog:man ratio was 1 dog for each 42 and 51 human beings, in the areas without and with sterilization, respectively. The animal population size increased in both regions, due mainly to the abandonment of domestic dogs. Mortality rate decreased throughout the study period. Survival probabilities did not differ between genders, but males entered the population in higher numbers. There were no differences in abundance, survival and recruitment between the regions, indicating that sterilization did not affect the population dynamics. Our findings indicate that the observed animal dynamics were influenced by density-independent factors, and that sterilization might not be a viable and effective strategy in regions where availability of resources is low and animal abandonment rates are high. Furthermore, the high demographic turnover rates observed render the canine free-roaming population younger, thus more susceptible to diseases, especially to rabies and leishmaniasis. We conclude by stressing the importance of implementing educational programs to promote responsible animal ownership and effective strategies against abandonment practices. PMID:29091961

  17. Abundance, survival, recruitment and effectiveness of sterilization of free-roaming dogs: A capture and recapture study in Brazil.

    PubMed

    Belo, Vinícius Silva; Struchiner, Claudio José; Werneck, Guilherme Loureiro; Teixeira Neto, Rafael Gonçalves; Tonelli, Gabriel Barbosa; de Carvalho Júnior, Clóvis Gomes; Ribeiro, Renata Aparecida Nascimento; da Silva, Eduardo Sérgio

    2017-01-01

    The existence of free-roaming dogs raises important issues in animal welfare and in public health. A proper understanding of these animals' ecology is useful as a necessary input to plan strategies to control these populations. The present study addresses the population dynamics and the effectiveness of the sterilization of unrestricted dogs using capture and recapture procedures suitable for open animal populations. Every two months, over a period of 14 months, we captured, tagged, released and recaptured dogs in two regions in a city in the southeast region of Brazil. In one of these regions the animals were also sterilized. Both regions had similar social, environmental and demographic features. We estimated the presence of 148 females and 227 males during the period of study. The average dog:man ratio was 1 dog for each 42 and 51 human beings, in the areas without and with sterilization, respectively. The animal population size increased in both regions, due mainly to the abandonment of domestic dogs. Mortality rate decreased throughout the study period. Survival probabilities did not differ between genders, but males entered the population in higher numbers. There were no differences in abundance, survival and recruitment between the regions, indicating that sterilization did not affect the population dynamics. Our findings indicate that the observed animal dynamics were influenced by density-independent factors, and that sterilization might not be a viable and effective strategy in regions where availability of resources is low and animal abandonment rates are high. Furthermore, the high demographic turnover rates observed render the canine free-roaming population younger, thus more susceptible to diseases, especially to rabies and leishmaniasis. We conclude by stressing the importance of implementing educational programs to promote responsible animal ownership and effective strategies against abandonment practices.

  18. A cost-effectiveness model to personalize antiviral therapy in naive patients with genotype 1 chronic hepatitis C.

    PubMed

    Iannazzo, Sergio; Colombatto, Piero; Ricco, Gabriele; Oliveri, Filippo; Bonino, Ferruccio; Brunetto, Maurizia R

    2015-03-01

    Rapid virologic response is the best predictor of sustained virologic response with dual therapy in genotype-1 chronic hepatitis C, and its evaluation was proposed to tailor triple therapy in F0-F2 patients. Bio-mathematical modelling of viral dynamics during dual therapy has potentially higher accuracy than rapid virologic in the identification of patients who will eventually achieve sustained response. Study's objective was the cost-effectiveness analysis of a personalized therapy in naïve F0-F2 patients with chronic hepatitis C based on a bio-mathematical model (model-guided strategy) rather than on rapid virologic response (guideline-guided strategy). A deterministic bio-mathematical model of the infected cell dynamics was validated in a cohort of 135 patients treated with dual therapy. A decision-analytic economic model was then developed to compare model-guided and guideline-guided strategies in the Italian setting. The outcomes of the cost-effectiveness analysis with model-guided and guideline-guided strategy were 19.1-19.4 and 18.9-19.3 quality-adjusted-life-years. Total per-patient lifetime costs were €25,200-€26,000 with model-guided strategy and €28,800-€29,900 with guideline-guided strategy. When comparing model-guided with guideline-guided strategy the former resulted more effective and less costly. The adoption of the bio-mathematical predictive criterion has the potential to improve the cost-effectiveness of a personalized therapy for chronic hepatitis C, reserving triple therapy for those patients who really need it. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  19. Cost-effectiveness of dryland forest restoration evaluated by spatial analysis of ecosystem services.

    PubMed

    Birch, Jennifer C; Newton, Adrian C; Aquino, Claudia Alvarez; Cantarello, Elena; Echeverría, Cristian; Kitzberger, Thomas; Schiappacasse, Ignacio; Garavito, Natalia Tejedor

    2010-12-14

    Although ecological restoration is widely used to combat environmental degradation, very few studies have evaluated the cost-effectiveness of this approach. We examine the potential impact of forest restoration on the value of multiple ecosystem services across four dryland areas in Latin America, by estimating the net value of ecosystem service benefits under different reforestation scenarios. The values of selected ecosystem services were mapped under each scenario, supported by the use of a spatially explicit model of forest dynamics. We explored the economic potential of a change in land use from livestock grazing to restored native forest using different discount rates and performed a cost-benefit analysis of three restoration scenarios. Results show that passive restoration is cost-effective for all study areas on the basis of the services analyzed, whereas the benefits from active restoration are generally outweighed by the relatively high costs involved. These findings were found to be relatively insensitive to discount rate but were sensitive to the market value of carbon. Substantial variation in values was recorded between study areas, demonstrating that ecosystem service values are strongly context specific. However, spatial analysis enabled localized areas of net benefits to be identified, indicating the value of this approach for identifying the relative costs and benefits of restoration interventions across a landscape.

  20. [Effects of biochar application on the abundance and structure of ammonia-oxidizer communities in coal-mining area.

    PubMed

    Liu, Yuan; Zhu, Ji Rong; Wu, Yu Chen; Shu, Liang Zuo

    2017-10-01

    As a new type of soil amendment, biochar can effectively improve soil fertility, structure and soil nitrogen transformation. We studied the effects of biochar application on soil properties, abundance and community structure of ammonia oxidizer in coal-mining area. The results showed that the biochar application significantly increased contents of soil NH4+-N, total nitrogen, available phosphorus and potassium. Compared with the control, no change in the abundance of ammonia-oxidizing archaea (AOA) was found under biochar treatment, but there was a significant increase in the abundance of ammonia-oxidizing bacteria (AOB). The analysis of T-RFLP profiles showed that biochar significantly increased the diversity indexes of AOA and AOB, and altered the community structure of both AOA and AOB. Improved soil nutrients as well as increased abundance and diversity of ammonia-oxidizing community to some extent indicated the potential of biochar application in reclamation of coal-mining area soil.

  1. Google Haul Out: Earth Observation Imagery and Digital Aerial Surveys in Coastal Wildlife Management and Abundance Estimation

    PubMed Central

    Moxley, Jerry H.; Bogomolni, Andrea; Hammill, Mike O.; Moore, Kathleen M. T.; Polito, Michael J.; Sette, Lisa; Sharp, W. Brian; Waring, Gordon T.; Gilbert, James R.; Halpin, Patrick N.; Johnston, David W.

    2017-01-01

    Abstract As the sampling frequency and resolution of Earth observation imagery increase, there are growing opportunities for novel applications in population monitoring. New methods are required to apply established analytical approaches to data collected from new observation platforms (e.g., satellites and unmanned aerial vehicles). Here, we present a method that estimates regional seasonal abundances for an understudied and growing population of gray seals (Halichoerus grypus) in southeastern Massachusetts, using opportunistic observations in Google Earth imagery. Abundance estimates are derived from digital aerial survey counts by adapting established correction-based analyses with telemetry behavioral observation to quantify survey biases. The result is a first regional understanding of gray seal abundance in the northeast US through opportunistic Earth observation imagery and repurposed animal telemetry data. As species observation data from Earth observation imagery become more ubiquitous, such methods provide a robust, adaptable, and cost-effective solution to monitoring animal colonies and understanding species abundances. PMID:29599542

  2. Google Haul Out: Earth Observation Imagery and Digital Aerial Surveys in Coastal Wildlife Management and Abundance Estimation.

    PubMed

    Moxley, Jerry H; Bogomolni, Andrea; Hammill, Mike O; Moore, Kathleen M T; Polito, Michael J; Sette, Lisa; Sharp, W Brian; Waring, Gordon T; Gilbert, James R; Halpin, Patrick N; Johnston, David W

    2017-08-01

    As the sampling frequency and resolution of Earth observation imagery increase, there are growing opportunities for novel applications in population monitoring. New methods are required to apply established analytical approaches to data collected from new observation platforms (e.g., satellites and unmanned aerial vehicles). Here, we present a method that estimates regional seasonal abundances for an understudied and growing population of gray seals (Halichoerus grypus) in southeastern Massachusetts, using opportunistic observations in Google Earth imagery. Abundance estimates are derived from digital aerial survey counts by adapting established correction-based analyses with telemetry behavioral observation to quantify survey biases. The result is a first regional understanding of gray seal abundance in the northeast US through opportunistic Earth observation imagery and repurposed animal telemetry data. As species observation data from Earth observation imagery become more ubiquitous, such methods provide a robust, adaptable, and cost-effective solution to monitoring animal colonies and understanding species abundances.

  3. RED SUPERGIANT STARS AS COSMIC ABUNDANCE PROBES: NLTE EFFECTS IN J-BAND IRON AND TITANIUM LINES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bergemann, Maria; Kudritzki, Rolf-Peter; Lind, Karin

    2012-06-01

    Detailed non-LTE (NLTE) calculations for red supergiant (RSG) stars are presented to investigate the influence of NLTE on the formation of atomic iron and titanium lines in the J band. With their enormous brightness at J band RSG stars are ideal probes of cosmic abundances. Recent LTE studies have found that metallicities accurate to 0.15 dex can be determined from medium-resolution spectroscopy of individual RSGs in galaxies as distant as 10 Mpc. The NLTE results obtained in this investigation support these findings. NLTE abundance corrections for iron are smaller than 0.05 dex for effective temperatures between 3400 K and 4200more » K and 0.1 dex at 4400 K. For titanium the NLTE abundance corrections vary smoothly between -0.4 dex and +0.2 dex as a function of effective temperature. For both elements, the corrections also depend on stellar gravity and metallicity. The physical reasons behind the NLTE corrections and the consequences for extragalactic J-band abundance studies are discussed.« less

  4. Cost-effectiveness of tubal patency tests.

    PubMed

    Verhoeve, H R; Moolenaar, L M; Hompes, P; van der Veen, F; Mol, B W J

    2013-04-01

    Guidelines are not in agreement on the most effective diagnostic scenario for tubal patency testing; therefore, we evaluated the cost-effectiveness of invasive tubal testing in subfertile couples compared with no testing and treatment. Cost-effectiveness analysis. Decision analytic framework. Computer-simulated cohort of subfertile women. We evaluated six scenarios: (1) no tests and no treatment; (2) immediate treatment without tubal testing; (3) delayed treatment without tubal testing; (4) hysterosalpingogram (HSG), followed by immediate or delayed treatment, according to diagnosis (tailored treatment); (5) HSG and a diagnostic laparoscopy (DL) in case HSG does not prove tubal patency, followed by tailored treatment; and (6) DL followed by tailored treatment. Expected cumulative live births after 3 years. Secondary outcomes were cost per couple and the incremental cost-effectiveness ratio. For a 30-year-old woman with otherwise unexplained subfertility for 12 months, 3-year cumulative live birth rates were 51.8, 78.1, 78.4, 78.4, 78.6 and 78.4%, and costs per couple were €0, €6968, €5063, €5410, €5405 and €6163 for scenarios 1, 2, 3, 4, 5 and 6, respectively. The incremental cost-effectiveness ratios compared with scenario 1 (reference strategy), were €26,541, €19,046, €20,372, €20,150 and €23,184 for scenarios 2, 3, 4, 5 and 6, respectively. Sensitivity analysis showed the model to be robust over a wide range of values for the variables. The most cost-effective scenario is to perform no diagnostic tubal tests and to delay in vitro fertilisation (IVF) treatment for at least 12 months for women younger than 38 years old, and to perform no tubal tests and start immediate IVF treatment from the age of 39 years. If an invasive diagnostic test is planned, HSG followed by tailored treatment, or a DL if HSG shows no tubal patency, is more cost-effective than DL. © 2013 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2013

  5. A Systematic Review of Cost-Effectiveness Studies Reporting Cost-per-DALY Averted

    PubMed Central

    Neumann, Peter J.; Thorat, Teja; Zhong, Yue; Anderson, Jordan; Farquhar, Megan; Salem, Mark; Sandberg, Eileen; Saret, Cayla J.; Wilkinson, Colby; Cohen, Joshua T.

    2016-01-01

    Introduction Calculating the cost per disability-adjusted life years (DALYs) averted associated with interventions is an increasing popular means of assessing the cost-effectiveness of strategies to improve population health. However, there has been no systematic attempt to characterize the literature and its evolution. Methods We conducted a systematic review of cost-effectiveness studies reporting cost-per-DALY averted from 2000 through 2015. We developed the Global Health Cost-Effectiveness Analysis (GHCEA) Registry, a repository of English-language cost-per-DALY averted studies indexed in PubMed. To identify candidate studies, we searched PubMed for articles with titles or abstracts containing the phrases “disability-adjusted” or “DALY”. Two reviewers with training in health economics independently reviewed each article selected in our abstract review, gathering information using a standardized data collection form. We summarized descriptive characteristics on study methodology: e.g., intervention type, country of study, study funder, study perspective, along with methodological and reporting practices over two time periods: 2000–2009 and 2010–2015. We analyzed the types of costs included in analyses, the study quality on a scale from 1 (low) to 7 (high), and examined the correlation between diseases researched and the burden of disease in different world regions. Results We identified 479 cost-per-DALY averted studies published from 2000 through 2015. Studies from Sub-Saharan Africa comprised the largest portion of published studies. The disease areas most commonly studied were communicable, maternal, neonatal, and nutritional disorders (67%), followed by non-communicable diseases (28%). A high proportion of studies evaluated primary prevention strategies (59%). Pharmaceutical interventions were commonly assessed (32%) followed by immunizations (28%). Adherence to good practices for conducting and reporting cost-effectiveness analysis varied

  6. Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM. I. Observed abundance gradients in dense clouds

    NASA Astrophysics Data System (ADS)

    Ruaud, M.; Wakelam, V.; Gratier, P.; Bonnell, I. A.

    2018-04-01

    Aim. We study the effect of large scale dynamics on the molecular composition of the dense interstellar medium during the transition between diffuse to dense clouds. Methods: We followed the formation of dense clouds (on sub-parsec scales) through the dynamics of the interstellar medium at galactic scales. We used results from smoothed particle hydrodynamics (SPH) simulations from which we extracted physical parameters that are used as inputs for our full gas-grain chemical model. In these simulations, the evolution of the interstellar matter is followed for 50 Myr. The warm low-density interstellar medium gas flows into spiral arms where orbit crowding produces the shock formation of dense clouds, which are held together temporarily by the external pressure. Results: We show that depending on the physical history of each SPH particle, the molecular composition of the modeled dense clouds presents a high dispersion in the computed abundances even if the local physical properties are similar. We find that carbon chains are the most affected species and show that these differences are directly connected to differences in (1) the electronic fraction, (2) the C/O ratio, and (3) the local physical conditions. We argue that differences in the dynamical evolution of the gas that formed dense clouds could account for the molecular diversity observed between and within these clouds. Conclusions: This study shows the importance of past physical conditions in establishing the chemical composition of the dense medium.

  7. The cost of preventing undernutrition: cost, cost-efficiency and cost-effectiveness of three cash-based interventions on nutrition outcomes in Dadu, Pakistan

    PubMed Central

    Trenouth, Lani; Colbourn, Timothy; Fenn, Bridget; Pietzsch, Silke; Myatt, Mark; Puett, Chloe

    2018-01-01

    Abstract Cash-based interventions (CBIs) increasingly are being used to deliver humanitarian assistance and there is growing interest in the cost-effectiveness of cash transfers for preventing undernutrition in emergency contexts. The objectives of this study were to assess the costs, cost-efficiency and cost-effectiveness in achieving nutrition outcomes of three CBIs in southern Pakistan: a ‘double cash’ (DC) transfer, a ‘standard cash’ (SC) transfer and a ‘fresh food voucher’ (FFV) transfer. Cash and FFVs were provided to poor households with children aged 6–48 months for 6 months in 2015. The SC and FFV interventions provided $14 monthly and the DC provided $28 monthly. Cost data were collected via institutional accounting records, interviews, programme observation, document review and household survey. Cost-effectiveness was assessed as cost per case of wasting, stunting and disability-adjusted life year (DALY) averted. Beneficiary costs were higher for the cash groups than the voucher group. Net total cost transfer ratios (TCTRs) were estimated as 1.82 for DC, 2.82 for SC and 2.73 for FFV. Yet, despite the higher operational costs, the FFV TCTR was lower than the SC TCTR when incorporating the participation cost to households, demonstrating the relevance of including beneficiary costs in cost-efficiency estimations. The DC intervention achieved a reduction in wasting, at $4865 per case averted; neither the SC nor the FFV interventions reduced wasting. The cost per case of stunting averted was $1290 for DC, $882 for SC and $883 for FFV. The cost per DALY averted was $641 for DC, $434 for SC and $563 for FFV without discounting or age weighting. These interventions are highly cost-effective by international thresholds. While it is debatable whether these resource requirements represent a feasible or sustainable investment given low health expenditures in Pakistan, these findings may provide justification for continuing Pakistan’s investment in

  8. Comparative costs and cost-effectiveness of behavioural interventions as part of HIV prevention strategies.

    PubMed

    Hsu, Justine; Zinsou, Cyprien; Parkhurst, Justin; N'Dour, Marguerite; Foyet, Léger; Mueller, Dirk H

    2013-01-01

    Behavioural interventions have been widely integrated in HIV/AIDS social marketing prevention strategies and are considered valuable in settings with high levels of risk behaviours and low levels of HIV/AIDS awareness. Despite their widespread application, there is a lack of economic evaluations comparing different behaviour change communication methods. This paper analyses the costs to increase awareness and the cost-effectiveness to influence behaviour change for five interventions in Benin. Cost and cost-effectiveness analyses used economic costs and primary effectiveness data drawn from surveys. Costs were collected for provider inputs required to implement the interventions in 2009 and analysed by 'person reached'. Cost-effectiveness was analysed by 'person reporting systematic condom use'. Sensitivity analyses were performed on all uncertain variables and major assumptions. Cost-per-person reached varies by method, with public outreach events the least costly (US$2.29) and billboards the most costly (US$25.07). Influence on reported behaviour was limited: only three of the five interventions were found to have a significant statistical correlation with reported condom use (i.e. magazines, radio broadcasts, public outreach events). Cost-effectiveness ratios per person reporting systematic condom use resulted in the following ranking: magazines, radio and public outreach events. Sensitivity analyses indicate rankings are insensitive to variation of key parameters although ratios must be interpreted with caution. This analysis suggests that while individual interventions are an attractive use of resources to raise awareness, this may not translate into a cost-effective impact on behaviour change. The study found that the extensive reach of public outreach events did not seem to influence behaviour change as cost-effectively when compared with magazines or radio broadcasts. Behavioural interventions are context-specific and their effectiveness influenced by a

  9. Cost Effectiveness in Evaluation Technical Assistance: Different Aspects of Measuring Cost and Outcomes.

    ERIC Educational Resources Information Center

    Estes, Gary D.

    The paper focuses on the Title I Evaluation Technical Assistance Centers to illustrate issues of measuring costs and deciding on outcome criteria before promoting "cost-effective" approaches. Effects are illustrated for varying resource allocations among personnel, travel, materials, and phone costs as a function of emphasizing…

  10. Current temporal trends in moth abundance are counter to predicted effects of climate change in an assemblage of subarctic forest moths.

    PubMed

    Hunter, Mark D; Kozlov, Mikhail V; Itämies, Juhani; Pulliainen, Erkki; Bäck, Jaana; Kyrö, Ella-Maria; Niemelä, Pekka

    2014-06-01

    Changes in climate are influencing the distribution and abundance of the world's biota, with significant consequences for biological diversity and ecosystem processes. Recent work has raised concern that populations of moths and butterflies (Lepidoptera) may be particularly susceptible to population declines under environmental change. Moreover, effects of climate change may be especially pronounced in high latitude ecosystems. Here, we examine population dynamics in an assemblage of subarctic forest moths in Finnish Lapland to assess current trajectories of population change. Moth counts were made continuously over a period of 32 years using light traps. From 456 species recorded, 80 were sufficiently abundant for detailed analyses of their population dynamics. Climate records indicated rapid increases in temperature and winter precipitation at our study site during the sampling period. However, 90% of moth populations were stable (57%) or increasing (33%) over the same period of study. Nonetheless, current population trends do not appear to reflect positive responses to climate change. Rather, time-series models illustrated that the per capita rates of change of moth species were more frequently associated negatively than positively with climate change variables, even as their populations were increasing. For example, the per capita rates of change of 35% of microlepidoptera were associated negatively with climate change variables. Moth life-history traits were not generally strong predictors of current population change or associations with climate change variables. However, 60% of moth species that fed as larvae on resources other than living vascular plants (e.g. litter, lichen, mosses) were associated negatively with climate change variables in time-series models, suggesting that such species may be particularly vulnerable to climate change. Overall, populations of subarctic forest moths in Finland are performing better than expected, and their populations

  11. Impact and cost-effectiveness of snail control to achieve disease control targets for schistosomiasis.

    PubMed

    Lo, Nathan C; Gurarie, David; Yoon, Nara; Coulibaly, Jean T; Bendavid, Eran; Andrews, Jason R; King, Charles H

    2018-01-23

    Schistosomiasis is a parasitic disease that affects over 240 million people globally. To improve population-level disease control, there is growing interest in adding chemical-based snail control interventions to interrupt the lifecycle of Schistosoma in its snail host to reduce parasite transmission. However, this approach is not widely implemented, and given environmental concerns, the optimal conditions for when snail control is appropriate are unclear. We assessed the potential impact and cost-effectiveness of various snail control strategies. We extended previously published dynamic, age-structured transmission and cost-effectiveness models to simulate mass drug administration (MDA) and focal snail control interventions against Schistosoma haematobium across a range of low-prevalence (5-20%) and high-prevalence (25-50%) rural Kenyan communities. We simulated strategies over a 10-year period of MDA targeting school children or entire communities, snail control, and combined strategies. We measured incremental cost-effectiveness in 2016 US dollars per disability-adjusted life year and defined a strategy as optimally cost-effective when maximizing health gains (averted disability-adjusted life years) with an incremental cost-effectiveness below a Kenya-specific economic threshold. In both low- and high-prevalence settings, community-wide MDA with additional snail control reduced total disability by an additional 40% compared with school-based MDA alone. The optimally cost-effective scenario included the addition of snail control to MDA in over 95% of simulations. These results support inclusion of snail control in global guidelines and national schistosomiasis control strategies for optimal disease control, especially in settings with high prevalence, "hot spots" of transmission, and noncompliance to MDA. Copyright © 2018 the Author(s). Published by PNAS.

  12. Impact and cost-effectiveness of snail control to achieve disease control targets for schistosomiasis

    PubMed Central

    Yoon, Nara; Coulibaly, Jean T.; Bendavid, Eran; Andrews, Jason R.; King, Charles H.

    2018-01-01

    Schistosomiasis is a parasitic disease that affects over 240 million people globally. To improve population-level disease control, there is growing interest in adding chemical-based snail control interventions to interrupt the lifecycle of Schistosoma in its snail host to reduce parasite transmission. However, this approach is not widely implemented, and given environmental concerns, the optimal conditions for when snail control is appropriate are unclear. We assessed the potential impact and cost-effectiveness of various snail control strategies. We extended previously published dynamic, age-structured transmission and cost-effectiveness models to simulate mass drug administration (MDA) and focal snail control interventions against Schistosoma haematobium across a range of low-prevalence (5–20%) and high-prevalence (25–50%) rural Kenyan communities. We simulated strategies over a 10-year period of MDA targeting school children or entire communities, snail control, and combined strategies. We measured incremental cost-effectiveness in 2016 US dollars per disability-adjusted life year and defined a strategy as optimally cost-effective when maximizing health gains (averted disability-adjusted life years) with an incremental cost-effectiveness below a Kenya-specific economic threshold. In both low- and high-prevalence settings, community-wide MDA with additional snail control reduced total disability by an additional 40% compared with school-based MDA alone. The optimally cost-effective scenario included the addition of snail control to MDA in over 95% of simulations. These results support inclusion of snail control in global guidelines and national schistosomiasis control strategies for optimal disease control, especially in settings with high prevalence, “hot spots” of transmission, and noncompliance to MDA. PMID:29301964

  13. Spatiotemporal heterogeneity in prey abundance and vulnerability shapes the foraging tactics of an omnivore

    USGS Publications Warehouse

    Rayl, Nathaniel; Bastille-Rousseau, Guillaume; Organ, John F.; Mumma, Matthew; Mahoney, Shane P.; Soulliere, Colleen; Lewis, Keith; Otto, Robert; Murray, Dennis; Waits, Lisette; Fuller, Todd

    2018-01-01

    Prey abundance and prey vulnerability vary across space and time, but we know little about how they mediate predator–prey interactions and predator foraging tactics. To evaluate the interplay between prey abundance, prey vulnerability and predator space use, we examined patterns of black bear (Ursus americanus) predation of caribou (Rangifer tarandus) neonates in Newfoundland, Canada using data from 317 collared individuals (9 bears, 34 adult female caribou, 274 caribou calves).During the caribou calving season, we predicted that landscape features would influence calf vulnerability to bear predation, and that bears would actively hunt calves by selecting areas associated with increased calf vulnerability. Further, we hypothesized that bears would dynamically adjust their foraging tactics in response to spatiotemporal changes in calf abundance and vulnerability (collectively, calf availability). Accordingly, we expected bears to actively hunt calves when they were most abundant and vulnerable, but switch to foraging on other resources as calf availability declined.As predicted, landscape heterogeneity influenced risk of mortality, and bears displayed the strongest selection for areas where they were most likely to kill calves, which suggested they were actively hunting caribou. Initially, the per‐capita rate at which bears killed calves followed a type‐I functional response, but as the calving season progressed and calf vulnerability declined, kill rates dissociated from calf abundance. In support of our hypothesis, bears adjusted their foraging tactics when they were less efficient at catching calves, highlighting the influence that predation phenology may have on predator space use. Contrary to our expectations, however, bears appeared to continue to hunt caribou as calf availability declined, but switched from a tactic of selecting areas of increased calf vulnerability to a tactic that maximized encounter rates with calves.Our results reveal that

  14. Cost-effectiveness acceptability curves revisited.

    PubMed

    Al, Maiwenn J

    2013-02-01

    Since the introduction of the cost-effectiveness acceptability curve (CEAC) in 1994, its use as a method to describe uncertainty around incremental cost-effectiveness ratios (ICERs) has steadily increased. In this paper, first the construction and interpretation of the CEAC is explained, both in the context of modelling studies and in the context of cost-effectiveness (CE) studies alongside clinical trials. Additionally, this paper reviews the advantages and limitations of the CEAC. Many of the perceived limitations can be attributed to the practice of interpreting the CEAC as a decision rule while it was not developed as such. It is argued that the CEAC is still a useful tool in describing and quantifying uncertainty around the ICER, especially in combination with other tools such as plots on the CE plane and value-of-information analysis.

  15. Synergistic Effects of Marine Reserves and Harvest Controls on the Abundance and Catch Dynamics of a Coral Reef Fishery.

    PubMed

    Hopf, Jess K; Jones, Geoffrey P; Williamson, David H; Connolly, Sean R

    2016-06-20

    Marine no-take reserves, where fishing and other extractive activities are prohibited, have well-established conservation benefits [1], yet their impacts on fisheries remains contentious [2-4]. For fishery species, reserves are often implemented alongside more conventional harvest strategies, including catch and size limits [2, 5]. However, catch and fish abundances observed post-intervention are often attributed to reserves, without explicitly estimating the potential contribution of concurrent management interventions [2, 3, 6-9]. Here we test a metapopulation model against observed fishery [10] and population [11] data for an important coral reef fishery (coral trout; Plectropomus spp.) in Australia's Great Barrier Reef Marine Park (GBRMP) to evaluate how the combined increase in reserve area [12] and reduction in fishing effort [13, 14] in 2004 influenced changes in fish stocks and the commercial fishery. We found that declines in catch, increases in catch rates, and increases in biomass since 2004 were substantially attributable to the integration of direct effort controls with the rezoning, rather than the rezoning alone. The combined management approach was estimated to have been more productive for fish and fisheries than if the rezoning had occurred alone and comparable to what would have been obtained with effort controls alone. Sensitivity analyses indicate that the direct effort controls prevented initial decreases in catch per unit effort that would have otherwise occurred with the rezoning. Our findings demonstrate that by concurrently restructuring the fishery, the conservation benefits of reserves were enhanced and the fishery cost of rezoning the reserve network was socialized, mitigating negative impacts on individual fishers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Gedanken Experiments in Educational Cost Effectiveness

    ERIC Educational Resources Information Center

    Brudner, Harvey J.

    1978-01-01

    Discusses the effectiveness of cost determining techniques in education. The areas discussed are: education and management; cost-effectiveness models; figures of merit determination; and the implications as they relate to the areas of audio-visual and computer educational technology. (Author/GA)

  17. Cost-inclusive evaluation: a banquet of approaches for including costs, benefits, and cost-effectiveness and cost-benefit analyses in your next evaluation.

    PubMed

    Yates, Brian T

    2009-02-01

    An introduction to the special issue on cost-inclusive evaluation, providing a brief history of the use of costs, benefits, cost-effectiveness, and cost-benefit analyses in the evaluation of human services. Two tables present brief glossaries of terms and analyses common in cost-inclusive program evaluation.

  18. Cost-effectiveness of treating normal tension glaucoma.

    PubMed

    Li, Emmy Y; Tham, Clement C; Chi, Stanley C; Lam, Dennis S

    2013-05-13

    To assess the long-term cost-effectiveness of treating normal tension glaucoma (NTG). A Markov decision-analytic health model was developed to determine the cost-effectiveness of treating NTG with IOP lowering therapy to prevent progressive visual field loss. Transitional probabilities were derived from the Collaborative Normal Tension Glaucoma Study and cost data obtained from the literature and the Medicare fee schedule. Incremental cost-effectiveness ratios (ICER) of treating all patients with NTG and treating selected individuals with risk factors for disease progression were determined using Monte Carlo simulation. Sensitivity analyses were performed by varying the cost of consultations, medications, laser/surgery, and adjusting utility loss from progressed states. The ICER of treating all patients with NTG over a 10-year period was United States (US) $34,225 per quality-adjusted life year (QALY). The ICER would be reduced when treatment was offered selectively to those with risk factors for disease progression. The ICER for treating NTG patients with disc hemorrhage, migraine, and those who were female were US $24,350, US $25,533, and US $27,000 per QALY, respectively. The cost-effectiveness of treating all NTG patients in this model was sensitive to cost fluctuation of medications, choice of utility score associated with disease progression, and insensitive to cost of consultations and laser/surgery. It is cost-effective, in the long-term, to offer IOP lowering therapy, aiming for a 30% reduction from the baseline, to all NTG patients. The incremental cost-effectiveness ratio of treating all patients with normal tension glaucoma over a 10-year period was $34,225 per quality-adjusted life year and should be offered to individuals in need.

  19. Cost-effective treatment for the couple with infertility.

    PubMed

    Van Voorhis, B J; Syrop, C H

    2000-12-01

    Although the evaluation of cost-effective approaches to infertility treatment remains in its infancy, several important principles have emerged from the initial studies in this field. Currently, in treating couples with infertility without tubal disease or severe male-factor infertility, the most cost-effective approach is to start with IUI or superovulation-IUI treatments before resorting to IVF procedures. The woman's age and number of sperm present for insemination are significant factors influencing cost-effectiveness. The influence of certain diagnoses on the cost-effectiveness of infertility treatments requires further study. Even when accounting for the costs associated with multiple gestations and premature deliveries, the cost of IVF decreases within the range of other cost-effective medical procedures and decreases to less than the willingness to pay for these procedures. Indeed, for patients with severe tubal disease, IVF has been found to be more cost-effective than surgical repair. The cost-effectiveness of IVF will likely improve as success rates show continued improvements over the course of time. In addition, usefulness of embryo selection and practices to reduce the likelihood of high-order multiple pregnancies, without reductions in pregnancy rates, will significantly impact cost-effectiveness. The exclusion of infertility treatments from insurance plans is unfortunate and accentuates the importance of physicians understanding the economics of infertility treatment with costs that are often passed directly to the patient. The erroneous economic policies and judgments that have led to inequities in access to infertility health care should not be tolerated.

  20. A low-cost solution for documenting distribution and abundance of endangered marine fauna and impacts from fisheries

    PubMed Central

    Das, Himansu; Davis, Patricia; Hines, Ellen; Kwan, Donna; Marsh, Helene; Ponnampalam, Louisa; Reynolds, John

    2017-01-01

    Fisheries bycatch is a widespread and serious issue that leads to declines of many important and threatened marine species. However, documenting the distribution, abundance, population trends and threats to sparse populations of marine species is often beyond the capacity of developing countries because such work is complex, time consuming and often extremely expensive. We have developed a flexible tool to document spatial distribution and population trends for dugongs and other marine species in the form of an interview questionnaire supported by a structured data upload sheet and a comprehensive project manual. Recognising the effort invested in getting interviewers to remote locations, the questionnaire is comprehensive, but low cost. The questionnaire has already been deployed in 18 countries across the Indo-Pacific region. Project teams spent an average of USD 5,000 per country and obtained large data sets on dugong distribution, trends, catch and bycatch, and threat overlaps. Findings indicated that >50% of respondents had never seen dugongs and that 20% had seen a single dugong in their lifetimes despite living and fishing in areas of known or suspected dugong habitat, suggesting that dugongs occurred in low numbers. Only 3% of respondents had seen mother and calf pairs, indicative of low reproductive output. Dugong hunting was still common in several countries. Gillnets and hook and line were the most common fishing gears, with the greatest mortality caused by gillnets. The questionnaire has also been used to study manatees in the Caribbean, coastal cetaceans along the eastern Gulf of Thailand and western Peninsular Malaysia, and river dolphins in Peru. This questionnaire is a powerful tool for studying distribution and relative abundance for marine species and fishery pressures, and determining potential conservation hotspot areas. We provide the questionnaire and supporting documents for open-access use by the scientific and conservation communities. PMID

  1. A low-cost solution for documenting distribution and abundance of endangered marine fauna and impacts from fisheries.

    PubMed

    Pilcher, Nicolas J; Adulyanukosol, Kanjana; Das, Himansu; Davis, Patricia; Hines, Ellen; Kwan, Donna; Marsh, Helene; Ponnampalam, Louisa; Reynolds, John

    2017-01-01

    Fisheries bycatch is a widespread and serious issue that leads to declines of many important and threatened marine species. However, documenting the distribution, abundance, population trends and threats to sparse populations of marine species is often beyond the capacity of developing countries because such work is complex, time consuming and often extremely expensive. We have developed a flexible tool to document spatial distribution and population trends for dugongs and other marine species in the form of an interview questionnaire supported by a structured data upload sheet and a comprehensive project manual. Recognising the effort invested in getting interviewers to remote locations, the questionnaire is comprehensive, but low cost. The questionnaire has already been deployed in 18 countries across the Indo-Pacific region. Project teams spent an average of USD 5,000 per country and obtained large data sets on dugong distribution, trends, catch and bycatch, and threat overlaps. Findings indicated that >50% of respondents had never seen dugongs and that 20% had seen a single dugong in their lifetimes despite living and fishing in areas of known or suspected dugong habitat, suggesting that dugongs occurred in low numbers. Only 3% of respondents had seen mother and calf pairs, indicative of low reproductive output. Dugong hunting was still common in several countries. Gillnets and hook and line were the most common fishing gears, with the greatest mortality caused by gillnets. The questionnaire has also been used to study manatees in the Caribbean, coastal cetaceans along the eastern Gulf of Thailand and western Peninsular Malaysia, and river dolphins in Peru. This questionnaire is a powerful tool for studying distribution and relative abundance for marine species and fishery pressures, and determining potential conservation hotspot areas. We provide the questionnaire and supporting documents for open-access use by the scientific and conservation communities.

  2. 49 CFR 639.21 - Determination of cost-effectiveness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Determination of cost-effectiveness. 639.21... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CAPITAL LEASES Cost-Effectiveness § 639.21 Determination of cost...-effectiveness comparison as described in this subpart, it may ask FTA to approve an alternate form of cost...

  3. Cost Effectiveness of Hybrid Solar Powerplants

    NASA Technical Reports Server (NTRS)

    Wen, L. C.; Steele, H. L.

    1983-01-01

    Report discusses cost effectiveness of high-temperature thermal storage system for representative parabolic dish solar powerplant. Economic viability of thermal storage system assesses; cost and performance projections made; cost of electricity generated by solar power plant also calculated.

  4. Cost-Effectiveness of Mass Dog Vaccination Campaigns against Rabies in Flores Island, Indonesia.

    PubMed

    Wera, E; Mourits, M C M; Siko, M M; Hogeveen, H

    2017-12-01

    A dynamic deterministic simulation model was developed to determine the cost-effectiveness of different mass dog vaccination strategies against rabies in a dog population representative of a typical village on Flores Island. Cost-effectiveness was measured as public cost per averted dog-rabies case. Simulations started with the introduction of one infectious dog into a susceptible dog population of 399 dogs and subsequently ran for a period of 10 years. The base scenario represented a situation without any control intervention. Evaluated vaccination strategies were as follows: annual vaccination campaigns with short-acting vaccine (immunity duration of 52 weeks) (AV_52), annual campaigns with long-acting vaccine (immunity duration of 156 weeks) (AV_156), biannual campaigns with short-acting vaccine (BV_52) and once-in-2-years campaigns with long-acting vaccine (O2V_156). The effectiveness of the vaccination strategies was simulated for vaccination coverages of 50% and 70%. Cumulative results were reported for the 10-year simulation period. The base scenario resulted in three epidemic waves, with a total of 1274 dog-rabies cases. The public cost of applying AV_52 at a coverage of 50% was US$5342 for a village. This strategy was unfavourable compared to other strategies, as it was costly and ineffective in controlling the epidemic. The costs of AV_52 at a coverage of 70% and AV_156 at a coverage of 70% were, respectively, US$3646 and US$3716, equivalent to US$3.00 and US$3.17 per averted dog-rabies case. Increasing the coverage of AV_156 from 50% to 70% reduced the number of cases by 7% and reduced the cost by US$1452, resulting in a cost-effectiveness ratio of US$1.81 per averted dog-rabies case. This simulation model provides an effective tool to explore the public cost-effectiveness of mass dog vaccination strategies in Flores Island. Insights obtained from the simulation results are useful for animal health authorities to support decision-making in rabies

  5. Are the Formation and Abundances of Metal-poor Stars the Result of Dust Dynamics?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hopkins, Philip F.; Conroy, Charlie, E-mail: phopkins@caltech.edu

    Large dust grains can fluctuate dramatically in their local density, relative to the gas, in neutral turbulent disks. Small, high-redshift galaxies (before reionization) represent ideal environments for this process. We show via simple arguments and simulations that order-of-magnitude fluctuations are expected in local abundances of large grains (>100 Å) under these conditions. This can have important consequences for star formation and stellar metal abundances in extremely metal-poor stars. Low-mass stars can form in dust-enhanced regions almost immediately after some dust forms even if the galaxy-average metallicity is too low for fragmentation to occur. We argue that the metal abundances ofmore » these “promoted” stars may contain interesting signatures as the CNO abundances (concentrated in large carbonaceous grains and ices) and Mg and Si (in large silicate grains) can be enhanced and/or fluctuate almost independently. Remarkably, the otherwise puzzling abundance patterns of some metal-poor stars can be well fit by standard IMF-averaged core-collapse SNe yields if we allow for fluctuating local dust-to-gas ratios. We also show that the observed log-normal distribution of enhancements in pure SNe yields, shows very large enhancements and variations up to factors of ≳100 as expected in the dust-promoted model, preferentially in the [C/Fe]-enhanced metal-poor stars. Together, this suggests that (1) dust exists in second-generation star formation, (2) local dust-to-gas ratio fluctuations occur in protogalaxies and can be important for star formation, and (3) the light element abundances of these stars may be affected by the local chemistry of dust where they formed, rather than directly tracing nucleosynthesis from earlier populations.« less

  6. Effectiveness and Cost Effectiveness of Oral Pre-Exposure Prophylaxis in a Portfolio of Prevention Programs for Injection Drug Users in Mixed HIV Epidemics

    PubMed Central

    Alistar, Sabina S.; Owens, Douglas K.; Brandeau, Margaret L.

    2014-01-01

    Background Pre-exposure prophylaxis with oral antiretroviral treatment (oral PrEP) for HIV-uninfected injection drug users (IDUs) is potentially useful in controlling HIV epidemics with a significant injection drug use component. We estimated the effectiveness and cost effectiveness of strategies for using oral PrEP in various combinations with methadone maintenance treatment (MMT) and antiretroviral treatment (ART) in Ukraine, a representative case for mixed HIV epidemics. Methods and Findings We developed a dynamic compartmental model of the HIV epidemic in a population of non-IDUs, IDUs who inject opiates, and IDUs in MMT, adding an oral PrEP program (tenofovir/emtricitabine, 49% susceptibility reduction) for uninfected IDUs. We analyzed intervention portfolios consisting of oral PrEP (25% or 50% of uninfected IDUs), MMT (25% of IDUs), and ART (80% of all eligible patients). We measured health care costs, quality-adjusted life years (QALYs), HIV prevalence, HIV infections averted, and incremental cost effectiveness. A combination of PrEP for 50% of IDUs and MMT lowered HIV prevalence the most in both IDUs and the general population. ART combined with MMT and PrEP (50% access) averted the most infections (14,267). For a PrEP cost of $950, the most cost-effective strategy was MMT, at $520/QALY gained versus no intervention. The next most cost-effective strategy consisted of MMT and ART, costing $1,000/QALY gained compared to MMT alone. Further adding PrEP (25% access) was also cost effective by World Health Organization standards, at $1,700/QALY gained. PrEP alone became as cost effective as MMT at a cost of $650, and cost saving at $370 or less. Conclusions Oral PrEP for IDUs can be part of an effective and cost-effective strategy to control HIV in regions where injection drug use is a significant driver of the epidemic. Where budgets are limited, focusing on MMT and ART access should be the priority, unless PrEP has low cost. PMID:24489747

  7. Scaling up integrated prevention campaigns for global health: costs and cost-effectiveness in 70 countries.

    PubMed

    Marseille, Elliot; Jiwani, Aliya; Raut, Abhishek; Verguet, Stéphane; Walson, Judd; Kahn, James G

    2014-06-26

    This study estimated the health impact, cost and cost-effectiveness of an integrated prevention campaign (IPC) focused on diarrhoea, malaria and HIV in 70 countries ranked by per capita disability-adjusted life-year (DALY) burden for the three diseases. We constructed a deterministic cost-effectiveness model portraying an IPC combining counselling and testing, cotrimoxazole prophylaxis, referral to treatment and condom distribution for HIV prevention; bed nets for malaria prevention; and provision of household water filters for diarrhoea prevention. We developed a mix of empirical and modelled cost and health impact estimates applied to all 70 countries. One-way, multiway and scenario sensitivity analyses were conducted to document the strength of our findings. We used a healthcare payer's perspective, discounted costs and DALYs at 3% per year and denominated cost in 2012 US dollars. The primary outcome was cost-effectiveness expressed as net cost per DALY averted. Other outcomes included cost of the IPC; net IPC costs adjusted for averted and additional medical costs and DALYs averted. Implementation of the IPC in the 10 most cost-effective countries at 15% population coverage would cost US$583 million over 3 years (adjusted costs of US$398 million), averting 8.0 million DALYs. Extending IPC programmes to all 70 of the identified high-burden countries at 15% coverage would cost an adjusted US$51.3 billion and avert 78.7 million DALYs. Incremental cost-effectiveness ranged from US$49 per DALY averted for the 10 countries with the most favourable cost-effectiveness to US$119, US$181, US$335, US$1692 and US$8340 per DALY averted as each successive group of 10 countries is added ordered by decreasing cost-effectiveness. IPC appears cost-effective in many settings, and has the potential to substantially reduce the burden of disease in resource-poor countries. This study increases confidence that IPC can be an important new approach for enhancing global health

  8. Weed management practices affect the diversity and relative abundance of physic nut mites.

    PubMed

    Saraiva, Althiéris de Sousa; Sarmento, Renato A; Erasmo, Eduardo A L; Pedro-Neto, Marçal; de Souza, Danival José; Teodoro, Adenir V; Silva, Daniella G

    2015-03-01

    Crop management practices determine weed community, which in turn may influence patterns of diversity and abundance of associated arthropods. This study aimed to evaluate whether local weed management practices influence the diversity and relative abundance of phytophagous and predatory mites, as well as mites with undefined feeding habits--of the families Oribatidae and Acaridae--in a physic nut (Jatropha curcas L.) plantation subjected to (1) within-row herbicide spraying and between-row mowing; (2) within-row herbicide spraying and no between-row mowing; (3) within-row weeding and between-row mowing; (4) within-row weeding and no between-row mowing; and (5) unmanaged (control). The herbicide used was glyphosate. Herbicide treatments resulted in higher diversity and relative abundance of predatory mites and mites with undefined feeding habit on physic nut shrubs. This was probably due to the toxic effects of the herbicide on mites or to removal of weeds. Within-row herbicide spraying combined with between-row mowing was the treatment that most contributed to this effect. Our results show that within-row weeds harbor important species of predatory mites and mites with undefined feeding habit. However, the dynamics of such mites in the system can be changed according to the weed management practice applied. Among the predatory mites of the family Phytoseiidae Amblydromalus sp. was the most abundant, whereas Brevipalpus phoenicis was the most frequent phytophagous mite and an unidentified oribatid species was the most frequent mite with undefined feeding habit.

  9. The cost diary: a method to measure direct and indirect costs in cost-effectiveness research.

    PubMed

    Goossens, M E; Rutten-van Mölken, M P; Vlaeyen, J W; van der Linden, S M

    2000-07-01

    From a societal perspective long-term clinical trials or follow-up studies should preferably not only include an evaluation of the health effect for the patient, but also an economic evaluation. In order to yield comprehensive medical and nonmedical resource use data, we at least partly depend on respondents' recall for collecting these costing data. A patient cost diary was developed in order to estimate total resource use, expenses, and lost production due to illness and treatment. We applied the cost diary in two randomized clinical trials evaluating the cost-effectiveness of behavioral rehabilitation in 205 fibromyalgia and chronic low back pain patients. The use of the diary was evaluated, studying the feasibility, the influence of the period of data collection on the results, and some aspects of validity. Eighty-five percent of the patients completed at least one diary and in total 68% of the diaries were returned. Although the results for the three alternative periods of data collection (keeping the diary 1 week every month, 2 weeks every 2 months, or a full year) were not significantly different, they were only moderately correlated. Finally, self-reported specialist care contacts were generally in agreement with data from an insurance company. However, for physiotherapy contacts there were differences between the self-reported and insurance data. This study shows how the cost diary might be used successfully in cost-effectiveness studies.

  10. Cost and Cost-Effectiveness of Students for Nutrition and eXercise (SNaX).

    PubMed

    Ladapo, Joseph A; Bogart, Laura M; Klein, David J; Cowgill, Burton O; Uyeda, Kimberly; Binkle, David G; Stevens, Elizabeth R; Schuster, Mark A

    2016-04-01

    To examine the cost and cost-effectiveness of implementing Students for Nutrition and eXercise (SNaX), a 5-week middle school-based obesity-prevention intervention combining school-wide environmental changes, multimedia, encouragement to eat healthy school cafeteria foods, and peer-led education. Five intervention and 5 control middle schools (mean enrollment, 1520 students) from the Los Angeles Unified School District participated in a randomized controlled trial of SNaX. Acquisition costs for materials and time and wage data for employees involved in implementing the program were used to estimate fixed and variable costs. Cost-effectiveness was determined using the ratio of variable costs to program efficacy outcomes. The costs of implementing the program over 5 weeks were $5433.26 per school in fixed costs and $2.11 per student in variable costs, equaling a total cost of $8637.17 per school, or $0.23 per student per day. This investment yielded significant increases in the proportion of students served fruit and lunch and a significant decrease in the proportion of students buying snacks. The cost-effectiveness of the program, per student over 5 weeks, was $1.20 per additional fruit served during meals, $8.43 per additional full-priced lunch served, $2.11 per additional reduced-price/free lunch served, and $1.69 per reduction in snacks sold. SNaX demonstrated the feasibility and cost-effectiveness of a middle school-based obesity-prevention intervention combining school-wide environmental changes, multimedia, encouragement to eat healthy school cafeteria foods, and peer-led education. Its cost is modest and unlikely to be a significant barrier to adoption for many schools considering its implementation. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  11. Cost-effectiveness analysis of sandhill crane habitat management

    USGS Publications Warehouse

    Kessler, Andrew C.; Merchant, James W.; Shultz, Steven D.; Allen, Craig R.

    2013-01-01

    Invasive species often threaten native wildlife populations and strain the budgets of agencies charged with wildlife management. We demonstrate the potential of cost-effectiveness analysis to improve the efficiency and value of efforts to enhance sandhill crane (Grus canadensis) roosting habitat. We focus on the central Platte River in Nebraska (USA), a region of international ecological importance for migrating avian species including sandhill cranes. Cost-effectiveness analysis is a valuation process designed to compare alternative actions based on the cost of achieving a pre-determined objective. We estimated costs for removal of invasive vegetation using geographic information system simulations and calculated benefits as the increase in area of sandhill crane roosting habitat. We generated cost effectiveness values for removing invasive vegetation on 7 land parcels and for the entire central Platte River to compare the cost-effectiveness of management at specific sites and for the central Platte River landscape. Median cost effectiveness values for the 7 land parcels evaluated suggest that costs for creating 1 additional hectare of sandhill crane roosting habitat totaled US $1,595. By contrast, we found that creating an additional hectare of sandhill crane roosting habitat could cost as much as US $12,010 for some areas in the central Platte River, indicating substantial cost savings can be achieved by using a cost effectiveness analysis to target specific land parcels for management. Cost-effectiveness analysis, used in conjunction with geographic information systems, can provide decision-makers with a new tool for identifying the most economically efficient allocation of resources to achieve habitat management goals.

  12. Interannual bumble bee abundance is driven by indirect climate effects on floral resource phenology.

    PubMed

    Ogilvie, Jane E; Griffin, Sean R; Gezon, Zachariah J; Inouye, Brian D; Underwood, Nora; Inouye, David W; Irwin, Rebecca E

    2017-12-01

    Climate change can influence consumer populations both directly, by affecting survival and reproduction, and indirectly, by altering resources. However, little is known about the relative importance of direct and indirect effects, particularly for species important to ecosystem functioning, like pollinators. We used structural equation modelling to test the importance of direct and indirect (via floral resources) climate effects on the interannual abundance of three subalpine bumble bee species. In addition, we used long-term data to examine how climate and floral resources have changed over time. Over 8 years, bee abundances were driven primarily by the indirect effects of climate on the temporal distribution of floral resources. Over 43 years, aspects of floral phenology changed in ways that indicate species-specific effects on bees. Our study suggests that climate-driven alterations in floral resource phenology can play a critical role in governing bee population responses to global change. © 2017 John Wiley & Sons Ltd/CNRS.

  13. Disease dynamics and costly punishment can foster socially imposed monogamy.

    PubMed

    Bauch, Chris T; McElreath, Richard

    2016-04-05

    Socially imposed monogamy in humans is an evolutionary puzzle because it requires costly punishment by those who impose the norm. Moreover, most societies were--and are--polygynous; yet many larger human societies transitioned from polygyny to socially imposed monogamy beginning with the advent of agriculture and larger residential groups. We use a simulation model to explore how interactions between group size, sexually transmitted infection (STI) dynamics and social norms can explain the timing and emergence of socially imposed monogamy. Polygyny dominates when groups are too small to sustain STIs. However, in larger groups, STIs become endemic (especially in concurrent polygynist networks) and have an impact on fertility, thereby mediating multilevel selection. Punishment of polygynists improves monogamist fitness within groups by reducing their STI exposure, and between groups by enabling punishing monogamist groups to outcompete polygynists. This suggests pathways for the emergence of socially imposed monogamy, and enriches our understanding of costly punishment evolution.

  14. Disease dynamics and costly punishment can foster socially imposed monogamy

    PubMed Central

    Bauch, Chris T.; McElreath, Richard

    2016-01-01

    Socially imposed monogamy in humans is an evolutionary puzzle because it requires costly punishment by those who impose the norm. Moreover, most societies were—and are—polygynous; yet many larger human societies transitioned from polygyny to socially imposed monogamy beginning with the advent of agriculture and larger residential groups. We use a simulation model to explore how interactions between group size, sexually transmitted infection (STI) dynamics and social norms can explain the timing and emergence of socially imposed monogamy. Polygyny dominates when groups are too small to sustain STIs. However, in larger groups, STIs become endemic (especially in concurrent polygynist networks) and have an impact on fertility, thereby mediating multilevel selection. Punishment of polygynists improves monogamist fitness within groups by reducing their STI exposure, and between groups by enabling punishing monogamist groups to outcompete polygynists. This suggests pathways for the emergence of socially imposed monogamy, and enriches our understanding of costly punishment evolution. PMID:27044573

  15. Costs of diarrheal disease and the cost-effectiveness of a rotavirus vaccination program in kyrgyzstan.

    PubMed

    Flem, Elmira T; Latipov, Renat; Nurmatov, Zuridin S; Xue, Yiting; Kasymbekova, Kaliya T; Rheingans, Richard D

    2009-11-01

    We examined the cost-effectiveness of a rotavirus immunization program in Kyrgyzstan, a country eligible for vaccine funding from the GAVI Alliance. We estimated the burden of rotavirus disease and its economic consequences by using national and international data. A cost-effectiveness analysis was conducted from government and societal perspectives, along with a range of 1-way sensitivity analyses. Rotavirus-related hospitalizations and outpatient visits cost US$580,864 annually, of which $421,658 (73%) is direct medical costs and $159,206 (27%) is nonmedical and indirect costs. With 95% coverage, vaccination could prevent 75% of rotavirus-related hospitalizations and deaths and 56% of outpatient visits and could avert $386,193 (66%) in total costs annually. The medical break-even price at which averted direct medical costs equal vaccination costs is $0.65/dose; the societal break-even price is $1.14/dose for a 2-dose regimen. At the current GAVI Alliance-subsidized vaccine price of $0.60/course, rotavirus vaccination is cost-saving for the government. Vaccination is cost-effective at a vaccine price $9.41/dose, according to the cost-effectiveness standard set by the 2002 World Health Report. Addition of rotavirus vaccines to childhood immunization in Kyrgyzstan could substantially reduce disease burden and associated costs. Vaccination would be cost-effective from the national perspective at a vaccine price $9.41 per dose.

  16. The Potential Cost-Effectiveness of Amblyopia Screening Programs

    PubMed Central

    Rein, David B.; Wittenborn, John S.; Zhang, Xinzhi; Song, Michael; Saaddine, Jinan B.

    2013-01-01

    Background To estimate the incremental cost-effectiveness of amblyopia screening at preschool and kindergarten, we compared the costs and benefits of 3 amblyopia screening scenarios to no screening and to each other: (1) acuity/stereopsis (A/S) screening at kindergarten, (2) A/S screening at preschool and kindergarten, and (3) photoscreening at preschool and A/S screening at kindergarten. Methods We programmed a probabilistic microsimulation model of amblyopia natural history and response to treatment with screening costs and outcomes estimated from 2 state programs. We calculated the probability that no screening and each of the 3 interventions were most cost-effective per incremental quality-adjusted life year (QALY) gained and case avoided. Results Assuming a minimal 0.01 utility loss from monocular vision loss, no screening was most cost-effective with a willingness to pay (WTP) of less than $16,000 per QALY gained. A/S screening at kindergarten alone was most cost-effective between a WTP of $17,000 and $21,000. A/S screening at preschool and kindergarten was most cost-effective between a WTP of $22,000 and $75,000, and photoscreening at preschool and A/S screening at kindergarten was most cost-effective at a WTP greater than $75,000. Cost-effectiveness substantially improved when assuming a greater utility loss. All scenarios were cost-effective when assuming a WTP of $10,500 per case of amblyopia cured. Conclusions All 3 screening interventions evaluated are likely to be considered cost-effective relative to many other potential public health programs. The choice of screening option depends on budgetary resources and the value placed on monocular vision loss prevention by funding agencies. PMID:21877675

  17. Cost-Effectiveness Analysis of Morcellation Hysterectomy for Myomas.

    PubMed

    Bortoletto, Pietro; Einerson, Brett D; Miller, Emily S; Milad, Magdy P

    2015-01-01

    To estimate the cost-effectiveness of eliminating morcellation in the surgical treatment of leiomyomas from a societal perspective. Cost-effectiveness analysis. Not applicable. A theoretical cohort of women undergoing hysterectomy for myoma disease large enough to require morcellation. None. None. A decision analysis model was constructed using probabilities, costs, and utility data from published sources. A cost-effectiveness analysis analyzing both quality-adjusted life years (QALYs) and cases of disseminated cancer was performed to determine the incremental cost-effectiveness ratio (ICER) of eliminating morcellation as a tool in the surgical treatment of leiomyomas. Costs and utilities were discounted using standard methodology. The base case included health care system costs and costs incurred by the patient for surgery-related disability. One-way sensitivity analyses were performed to assess the effect of various assumptions. The cost to prevent 1 case of disseminated cancer was $10 540 832. A strategy of nonmorcellation hysterectomy via laparotomy costed more ($30 359.92 vs $20 853.15) and yielded more QALYs (21.284 vs 21.280) relative to morcellation hysterectomy. The ICER for nonmorcellation hysterectomy compared with morcellation hysterectomy was $2 184 172 per QALY. Health care costs (prolonged hospitalizations) and costs to patients of prolonged time away from work were the primary drivers of cost differential between the 2 strategies. Even when the incidence of occult sarcoma in leiomyoma surgery was ranged to twice that reported in the literature (.98%), the ICER for nonmorcellation hysterectomy was $644 393.30. Eliminating morcellation hysterectomy as a treatment for myomas is not cost-effective under a wide variety of probability and cost assumptions. Performing laparotomy for all patients who might otherwise be candidates for morcellation hysterectomy is a costly policy from a societal perspective. Copyright © 2015 AAGL. Published by Elsevier Inc

  18. Cost-effectiveness of strategies to enhance mammography use.

    PubMed

    Fishman, P; Taplin, S; Meyer, D; Barlow, W

    2000-01-01

    To estimate the cost-effectiveness of three strategies to increase breast cancer screening with mammography (reminder postcard, reminder telephone call, and motivational telephone call). Cost accounting for each strategy followed by cost-effectiveness analysis. DATA SOURCE FOR EFFECTIVENESS: Randomized trial of three strategies conducted at Group Health Cooperative of Puget Sound (GHC). Women 50 to 79 years of age who were enrolled in GHC's breast cancer screening program who did not schedule screening mammography within 2 months after it was recommended by letter. Health plan. Marginal cost-effectiveness of each additional woman screened. Because of its high cost (about $26 per call) and intermediate effectiveness, the motivational call was the least cost-effective strategy. If it was assumed that 50% of the women who scheduled mammography after receiving the reminder postcard would have scheduled mammography within 10 months even without it, marginal cost-effectiveness for the postcard among all women was $22 per woman screened versus $92 for the reminder call. Among women with no previous mammography, the marginal cost-effectiveness for the postcard was $70 versus $100 for the reminder call. Among women with no previous mammography, the choice between the reminder postcard and the reminder call was sensitive to assumptions about the percentage of women expected to receive mammography in the absence of other promotional strategies. A simple reminder postcard is the most cost-effective way to increase mammography. Choices about how to promote mammography will ultimately depend on plan values and willingness to invest in promotional strategies that increase participation at higher unit costs.

  19. 42 CFR 457.1015 - Cost-effectiveness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Cost-effectiveness. 457.1015 Section 457.1015 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Waivers: General Provisions § 457.1015 Cost-effectiveness. (a) Definition. For purposes of this subpart...

  20. Axiomatic foundations for cost-effectiveness analysis.

    PubMed

    Canning, David

    2013-12-01

    We show that individual utilities can be measured in units of healthy life years. Social preferences over these life metric utilities are assumed to satisfy the Pareto principle, anonymity, and invariance to a change in origin. These axioms generate a utilitarian social welfare function implying the use of cost-effectiveness analysis in ordering health projects, based on maximizing the healthy years equivalents gained from a fixed health budget. For projects outside the health sector, our cost-effectiveness axioms imply a form of cost-benefit analysis where both costs and benefits are measured in equivalent healthy life years. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Cost and cost-effectiveness of tuberculosis treatment shortening: a model-based analysis.

    PubMed

    Gomez, G B; Dowdy, D W; Bastos, M L; Zwerling, A; Sweeney, S; Foster, N; Trajman, A; Islam, M A; Kapiga, S; Sinanovic, E; Knight, G M; White, R G; Wells, W A; Cobelens, F G; Vassall, A

    2016-12-01

    Despite improvements in treatment success rates for tuberculosis (TB), current six-month regimen duration remains a challenge for many National TB Programmes, health systems, and patients. There is increasing investment in the development of shortened regimens with a number of candidates in phase 3 trials. We developed an individual-based decision analytic model to assess the cost-effectiveness of a hypothetical four-month regimen for first-line treatment of TB, assuming non-inferiority to current regimens of six-month duration. The model was populated using extensive, empirically-collected data to estimate the economic impact on both health systems and patients of regimen shortening for first-line TB treatment in South Africa, Brazil, Bangladesh, and Tanzania. We explicitly considered 'real world' constraints such as sub-optimal guideline adherence. From a societal perspective, a shortened regimen, priced at USD1 per day, could be a cost-saving option in South Africa, Brazil, and Tanzania, but would not be cost-effective in Bangladesh when compared to one gross domestic product (GDP) per capita. Incorporating 'real world' constraints reduces cost-effectiveness. Patient-incurred costs could be reduced in all settings. From a health service perspective, increased drug costs need to be balanced against decreased delivery costs. The new regimen would remain a cost-effective option, when compared to each countries' GDP per capita, even if new drugs cost up to USD7.5 and USD53.8 per day in South Africa and Brazil; this threshold was above USD1 in Tanzania and under USD1 in Bangladesh. Reducing the duration of first-line TB treatment has the potential for substantial economic gains from a patient perspective. The potential economic gains for health services may also be important, but will be context-specific and dependent on the appropriate pricing of any new regimen.

  2. [Cost-effectiveness of laparoscopic versus open cholecystectomy].

    PubMed

    Fajardo, Roosevelt; Valenzuela, José Ignacio; Olaya, Sandra Catalina; Quintero, Gustavo; Carrasquilla, Gabriel; Pinzón, Carlos Eduardo; López, Catalina; Ramírez, Juan Camilo

    2011-01-01

    Cholecystectomy has been the subject of several clinical and cost comparison studies. The results of open or laparoscopy cholecystectomy were compared in terms of cost and effectiveness from the perspective of health care institutions and from that of the patients. The cost-effectiveness study was undertaken at two university hospitals in Bogotá, Colombia. The approach was to select the type of cholecystectomy retrospectively and then assess the result prospectively. The cost analysis used the combined approach of micro-costs and daily average cost. Patient resource consumption was gathered from the time of surgery room entry to time of discharge. A sample of 376 patients with cholelithiasis/cystitis (May 2005-June 2006) was selected--156 underwent open cholecystectomy and 220 underwent laparoscopic cholecystectomy. The following data were tabulated: (1) frequency of complications and mortality, post-surgical hospital stay, (2) reincorporation to daily activities, (3) surgery duration, (4) direct medical costs, (5) costs to the patient, and (6) mean and incremental cost-effectiveness ratios. Frequency of complications was 13.5% for open cholecystectomy and 6.4% for laparoscopic cholecystectomy (p=0.02); hospital stay was longer in open cholecystectomy than in laparoscopic cholecystectomy (p=0.003) as well as the reincorporation to daily activities reported by the patients (p<0.001). The duration of open cholecystectomy was 22 min longer than laparoscopic cholecystectomy (p<0.001). The average cost of laparoscopic cholecystectomy was lower than open cholecystectomy and laparoscopic cholecystectomy was more cost-effective than open cholecystectomy (US$ 995 vs. US$ 1,048, respectively). The patient out-of-pocket expenses were greater in open cholecystectomy compared to laparoscopic cholecystectomy (p=0.015). Mortality was zero. The open laparoscopy procedure was associated with longer hospital stays, where as the cholecystectomy procedure required a longer surgical

  3. Some Observations on Cost-Effectiveness Analysis in Education.

    ERIC Educational Resources Information Center

    Geske, Terry G.

    1979-01-01

    The general nature of cost-effectiveness analysis is discussed, analytical frameworks for conducting cost-effectiveness studies are described, and some of the problems inherent in measuring educational costs and in assessing program effectiveness are addressed. (Author/IRT)

  4. Cost-effective conservation planning: lessons from economics.

    PubMed

    Duke, Joshua M; Dundas, Steven J; Messer, Kent D

    2013-08-15

    Economists advocate that the billions of public dollars spent on conservation be allocated to achieve the largest possible social benefit. This is "cost-effective conservation"-a process that incorporates both monetized benefits and costs. Though controversial, cost-effective conservation is poorly understood and rarely implemented by planners. Drawing from the largest publicly financed conservation programs in the United States, this paper seeks to improve the communication from economists to planners and to overcome resistance to cost-effective conservation. Fifteen practical lessons are distilled, including the negative implications of limiting selection with political constraints, using nonmonetized benefit measures or benefit indices, ignoring development risk, using incomplete cost measures, employing cost measures sequentially, and using benefit indices to capture costs. The paper highlights interrelationships between benefits and complications such as capitalization and intertemporal planning. The paper concludes by identifying the challenges at the research frontier, including incentive problems associated with adverse selection, additionality, and slippage. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. A Review on Cost-Effectiveness and Cost-Utility of Psychosocial Care in Cancer Patients

    PubMed Central

    Jansen, Femke; van Zwieten, Valesca; Coupé, Veerle M. H.; Leemans, C. René; Verdonck-de Leeuw, Irma M.

    2016-01-01

    Several psychosocial care interventions have been found effective in improving psychosocial outcomes in cancer patients. At present, there is increasingly being asked for information on the value for money of this type of intervention. This review therefore evaluates current evidence from studies investigating cost-effectiveness or cost-utility of psychosocial care in cancer patients. A systematic search was conducted in PubMed and Web of Science yielding 539 unique records, of which 11 studies were included in the study. Studies were mainly performed in breast cancer populations or mixed cancer populations. Studied interventions included collaborative care (four studies), group interventions (four studies), individual psychological support (two studies), and individual psycho-education (one study). Seven studies assessed the cost-utility of psychosocial care (based on quality-adjusted-life-years) while three studies investigated its cost-effectiveness (based on profile of mood states [mood], Revised Impact of Events Scale [distress], 12-Item Health Survey [mental health], or Fear of Progression Questionnaire [fear of cancer progression]). One study did both. Costs included were intervention costs (three studies), intervention and direct medical costs (five studies), or intervention, direct medical, and direct nonmedical costs (three studies). In general, results indicated that psychosocial care is likely to be cost-effective at different, potentially acceptable, willingness-to-pay thresholds. Further research should be performed to provide more clear information as to which psychosocial care interventions are most cost-effective and for whom. In addition, more research should be performed encompassing potential important cost drivers from a societal perspective, such as productivity losses or informal care costs, in the analyses. PMID:27981151

  6. Sunspots, Starspots, and Elemental Abundances

    NASA Astrophysics Data System (ADS)

    Doschek, George A.; Warren, Harry P.

    2017-08-01

    The composition of plasma in solar and stellar atmospheres is not fixed, but varies from feature to feature. These variations are organized by the First Ionization Potential (FIP) of the element. Solar measurements often indicate that low FIP elements (< 10eV, such as Fe, Si, Mg) are enriched by factors of 3-4 in the corona relative to high FIP elements (>10 eV, such as C, N, O, Ar, He) compared to abundances in the photosphere. Stellar observations have also shown similar enrichments. An inverse FIP effect, where the low FIP elements are depleted, has been observed in stellar coronae of stars believed to have large starspots in their photospheres. The abundances are important for determining radiative loss rates in models, tracing the origin of the slow solar wind, and for understanding wave propagation in the chromosphere and corona. Recently, inverse FIP effects have been discovered in the Sun (Doschek, Warren, & Feldman 2015, ApJ, 808, L7) from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The inverse FIP regions seem always to be near sunspots and cover only a very small area (characteristic length = a few arcseconds). However, in pursuing the search for inverse FIP regions, we have found that in some sunspot groups the coronal abundance at a temperature of 3-4 MK can be near photospheric over much larger areas of the sun near the sunspots (e.g., 6,000 arcsec2). Also, sometimes the abundances at 3-4 MK are in between coronal and photospheric values. This can occur in small areas of an active region. It is predicted (Laming 2015, Sol. Phys., 12, 2) that the FIP effect should be highly variable in the corona. Several examples of coronal abundance variations are presented. Our work indicates that a comprehensive re-investigation of solar abundances is highly desirable. This work is supported by a NASA Hinode grant.

  7. Sustainable Phosphorus Loadings from Effective and Cost-Effective Phosphorus Management Around the Baltic Sea

    PubMed Central

    Bryhn, Andreas C.

    2009-01-01

    Nutrient over-enrichment of the Baltic Sea, accompanied by intensified algal blooms and decreasing water clarity, has aroused widespread concern in the surrounding countries during the last four decades. This work has used a well-tested dynamic mass-balance model to investigate which decrease in total phosphorus loading would be required to meet the environmental goal to restore the trophic state in the Baltic Sea to pre-1960s levels. Furthermore, the extent to which various abatement options may decrease the phosphorus loading in a cost-effective manner has been studied. Upgrading urban sewage treatment in the catchment could, alone or in combination with banning phosphates in detergents, be sufficient to meet the set environmental goal, at an estimated annual basin-wide cost of 0.21–0.43 billion euro. Such a plan would potentially decrease the total phosphorus loading to the Baltic Sea with 6,650–10,200 tonnes per year. PMID:19412551

  8. Cost Effective Prototyping

    NASA Technical Reports Server (NTRS)

    Wickman, Jerry L.; Kundu, Nikhil K.

    1996-01-01

    This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

  9. Clinical Benefits, Costs, and Cost-Effectiveness of Neonatal Intensive Care in Mexico

    PubMed Central

    Profit, Jochen; Lee, Diana; Zupancic, John A.; Papile, LuAnn; Gutierrez, Cristina; Goldie, Sue J.; Gonzalez-Pier, Eduardo; Salomon, Joshua A.

    2010-01-01

    Background Neonatal intensive care improves survival, but is associated with high costs and disability amongst survivors. Recent health reform in Mexico launched a new subsidized insurance program, necessitating informed choices on the different interventions that might be covered by the program, including neonatal intensive care. The purpose of this study was to estimate the clinical outcomes, costs, and cost-effectiveness of neonatal intensive care in Mexico. Methods and Findings A cost-effectiveness analysis was conducted using a decision analytic model of health and economic outcomes following preterm birth. Model parameters governing health outcomes were estimated from Mexican vital registration and hospital discharge databases, supplemented with meta-analyses and systematic reviews from the published literature. Costs were estimated on the basis of data provided by the Ministry of Health in Mexico and World Health Organization price lists, supplemented with published studies from other countries as needed. The model estimated changes in clinical outcomes, life expectancy, disability-free life expectancy, lifetime costs, disability-adjusted life years (DALYs), and incremental cost-effectiveness ratios (ICERs) for neonatal intensive care compared to no intensive care. Uncertainty around the results was characterized using one-way sensitivity analyses and a multivariate probabilistic sensitivity analysis. In the base-case analysis, neonatal intensive care for infants born at 24–26, 27–29, and 30–33 weeks gestational age prolonged life expectancy by 28, 43, and 34 years and averted 9, 15, and 12 DALYs, at incremental costs per infant of US$11,400, US$9,500, and US$3,000, respectively, compared to an alternative of no intensive care. The ICERs of neonatal intensive care at 24–26, 27–29, and 30–33 weeks were US$1,200, US$650, and US$240, per DALY averted, respectively. The findings were robust to variation in parameter values over wide ranges in

  10. Examining the cost-effectiveness of cancer screening promotion.

    PubMed

    Andersen, M Robyn; Urban, Nicole; Ramsey, Scott; Briss, Peter A

    2004-09-01

    Cost-effectiveness analyses (CEAs) can help to quantify the contribution of the promotion of a screening program to increased participation in screening. The cost-effectiveness (C/E) of screening promotion depends in large part on the endpoints of interest. At the most fundamental level, the C/E of a strategy for promoting screening would focus on the attendance rate, or cost per person screened, and the C/E would be influenced by the costs of promotion, as well as by the size and responsiveness of the target population. In addition, the costs of screening promotion (measured as the cost per additional participant in screening) can be included in a CEA estimate of the screening technology. In this case, depending on the efficacy of the screening test and the costs and influence of the promotion, the C/E of screening may improve or become poorer. In the current study, the authors reviewed the literature on the C/E of cancer screening promotion. The following lessons were learned regarding the C/E of screening and its promotion: 1) high-quality information on the C/E of screening is increasingly available; 2) cost-effective promotion of screening is dependent on cost-effective screening strategies; 3) quality-of-life effects may be important in assessing the overall C/E of screening programs; 4) research efforts aimed at identifying cost-effective approaches to screening promotion are useful but sparse; 5) C/E studies should be better incorporated into well designed effectiveness research efforts; 6) variations in C/E according to intervention characteristics, population characteristics, and context should be evaluated in greater depth; 7) the long-term effects of screening promotion are critical to assessing C/E; 8) the effects of promotion on costs of screening must be better understood; and 9) CEA must be interpreted in light of other information. The authors showed that CEA can be a valuable tool for understanding the merits of health promotion interventions and

  11. Cost-effectiveness of Lung Cancer Screening in Canada.

    PubMed

    Goffin, John R; Flanagan, William M; Miller, Anthony B; Fitzgerald, Natalie R; Memon, Saima; Wolfson, Michael C; Evans, William K

    2015-09-01

    The US National Lung Screening Trial supports screening for lung cancer among smokers using low-dose computed tomographic (LDCT) scans. The cost-effectiveness of screening in a publically funded health care system remains a concern. To assess the cost-effectiveness of LDCT scan screening for lung cancer within the Canadian health care system. The Cancer Risk Management Model (CRMM) simulated individual lives within the Canadian population from 2014 to 2034, incorporating cancer risk, disease management, outcome, and cost data. Smokers and former smokers eligible for lung cancer screening (30 pack-year smoking history, ages 55-74 years, for the reference scenario) were modeled, and performance parameters were calibrated to the National Lung Screening Trial (NLST). The reference screening scenario assumes annual scans to age 75 years, 60% participation by 10 years, 70% adherence to screening, and unchanged smoking rates. The CRMM outputs are aggregated, and costs (2008 Canadian dollars) and life-years are discounted 3% annually. The incremental cost-effectiveness ratio. Compared with no screening, the reference scenario saved 51,000 quality-adjusted life-years (QALY) and had an incremental cost-effectiveness ratio of CaD $52,000/QALY. If smoking history is modeled for 20 or 40 pack-years, incremental cost-effectiveness ratios of CaD $62,000 and CaD $43,000/QALY, respectively, were generated. Changes in participation rates altered life years saved but not the incremental cost-effectiveness ratio, while the incremental cost-effectiveness ratio is sensitive to changes in adherence. An adjunct smoking cessation program improving the quit rate by 22.5% improves the incremental cost-effectiveness ratio to CaD $24,000/QALY. Lung cancer screening with LDCT appears cost-effective in the publicly funded Canadian health care system. An adjunct smoking cessation program has the potential to improve outcomes.

  12. Hemiparasite abundance in an alpine treeline ecotone increases in response to atmospheric CO(2) enrichment.

    PubMed

    Hättenschwiler, Stephan; Zumbrunn, Thomas

    2006-02-01

    Populations of the annual hemiparasites Melampyrum pratense L. and Melampyrum sylvaticum L. were studied at the treeline in the Swiss Alps after 3 years of in situ CO(2) enrichment. The total density of Melampyrum doubled to an average of 44 individuals per square meter at elevated CO(2) compared to ambient CO(2). In response to elevated CO(2), the height of the more abundant and more evenly distributed M. pratense increased by 20%, the number of seeds per fruit by 21%, and the total seed dry mass per fruit by 27%, but the individual seed size did not change. These results suggest that rising atmospheric CO(2) may stimulate the reproductive output and increase the abundance of Melampyrum in the alpine treeline ecotone. Because hemiparasites can have important effects on community dynamics and ecosystem processes, notably the N cycle, changing Melampyrum abundance may potentially influence the functioning of alpine ecosystems in a future CO(2)-rich atmosphere.

  13. The bliss (not the problem) of motor abundance (not redundancy).

    PubMed

    Latash, Mark L

    2012-03-01

    Motor control is an area of natural science exploring how the nervous system interacts with other body parts and the environment to produce purposeful, coordinated actions. A central problem of motor control-the problem of motor redundancy-was formulated by Nikolai Bernstein as the problem of elimination of redundant degrees-of-freedom. Traditionally, this problem has been addressed using optimization methods based on a variety of cost functions. This review draws attention to a body of recent findings suggesting that the problem has been formulated incorrectly. An alternative view has been suggested as the principle of abundance, which considers the apparently redundant degrees-of-freedom as useful and even vital for many aspects of motor behavior. Over the past 10 years, dozens of publications have provided support for this view based on the ideas of synergic control, computational apparatus of the uncontrolled manifold hypothesis, and the equilibrium-point (referent configuration) hypothesis. In particular, large amounts of "good variance"-variance in the space of elements that has no effect on the overall performance-have been documented across a variety of natural actions. "Good variance" helps an abundant system to deal with secondary tasks and unexpected perturbations; its amount shows adaptive modulation across a variety of conditions. These data support the view that there is no problem of motor redundancy; there is bliss of motor abundance.

  14. Disentangling the effects of climate, density dependence, and harvest on an iconic large herbivore's population dynamics.

    PubMed

    Koons, David N; Colchero, Fernando; Hersey, Kent; Gimenez, Olivier

    2015-06-01

    Understanding the relative effects of climate, harvest, and density dependence on population dynamics is critical for guiding sound population management, especially for ungulates in arid and semiarid environments experiencing climate change. To address these issues for bison in southern Utah, USA, we applied a Bayesian state-space model to a 72-yr time series of abundance counts. While accounting for known harvest (as well as live removal) from the population, we found that the bison population in southern Utah exhibited a strong potential to grow from low density (β0 = 0.26; Bayesian credible interval based on 95% of the highest posterior density [BCI] = 0.19-0.33), and weak but statistically significant density dependence (β1 = -0.02, BCI = -0.04 to -0.004). Early spring temperatures also had strong positive effects on population growth (Pfat1 = 0.09, BCI = 0.04-0.14), much more so than precipitation and other temperature-related variables (model weight > three times more than that for other climate variables). Although we hypothesized that harvest is the primary driving force of bison population dynamics in southern Utah, our elasticity analysis indicated that changes in early spring temperature could have a greater relative effect on equilibrium abundance than either harvest or. the strength of density dependence. Our findings highlight the utility of incorporating elasticity analyses into state-space population models, and the need to include climatic processes in wildlife management policies and planning.

  15. Inorganic and organic fertilizers impact the abundance and proportion of antibiotic resistance and integron-integrase genes in agricultural grassland soil.

    PubMed

    Nõlvak, Hiie; Truu, Marika; Kanger, Kärt; Tampere, Mailiis; Espenberg, Mikk; Loit, Evelin; Raave, Henn; Truu, Jaak

    2016-08-15

    Soil fertilization with animal manure or its digestate may facilitate an important antibiotic resistance dissemination route from anthropogenic sources to the environment. This study examines the effect of mineral fertilizer (NH4NO3), cattle slurry and cattle slurry digestate amendment on the abundance and proportion dynamics of five antibiotic resistance genes (ARGs) and two classes of integron-integrase genes (intI1 and intI2) in agricultural grassland soil. Fertilization was performed thrice throughout one vegetation period. The targeted ARGs (sul1, tetA, blaCTX-M, blaOXA2 and qnrS) encode resistance to several major antibiotic classes used in veterinary medicine such as sulfonamides, tetracycline, cephalosporins, penicillin and fluoroquinolones, respectively. The non-fertilized grassland soil contained a stable background of tetA, blaCTX-M and sul1 genes. The type of applied fertilizer significantly affected ARGs and integron-integrase genes abundances and proportions in the bacterial community (p<0.001 in both cases), explaining 67.04% of the abundance and 42.95% of the proportion variations in the grassland soil. Both cattle slurry and cattle slurry digestate proved to be considerable sources of ARGs, especially sul1, as well as integron-integrases. Sul1, intI1 and intI2 levels in grassland soil were elevated in response to each organic fertilizer's application event, but this increase was followed by a stage of decrease, suggesting that microbes possessing these genes were predominantly entrained into soil via cattle slurry or its digestate application and had somewhat limited survival potential in a soil environment. However, the abundance of these three target genes did not decrease to a background level by the end of the study period. TetA was most abundant in mineral fertilizer treated soil and blaCTX-M in cattle slurry digestate amended soil. Despite significantly different abundances, the abundance dynamics of bacteria possessing these genes were

  16. Challenging official health cost estimates: an alternative view that incorporates the behavioural and economic effects of policy changes.

    PubMed

    Robbins, A; Robbins, G

    1992-01-01

    Cost estimates of health care policy changes are extremely important. Historically, however, the US government has done a poor job in projecting the actual cost of new health care programmes. These projections have been inaccurate primarily because government forecasters use 'static' methods that fail to incorporate the change in people's behaviour as a direct result of a new policy. In contrast, 'dynamic' forecasts incorporate the behavioural effects of policy changes on individuals and the economy. Static and dynamic estimates can lead to different results for 4 areas of US health policy: (a) the Medicare Catastrophic Coverage Act; (b) mandated health benefits; (c) health insurance tax subsidies; and (d) national health insurance. Improving health care policy requires the adoption of dynamic estimation practices, periodic appraisals evaluating the accuracy of official estimates in relation to actual experience, and clear presentation of proposed policy changes and estimates to policymakers and the general public.

  17. Cost and effectiveness of lung lobectomy by video-assisted thoracic surgery for lung cancer

    PubMed Central

    Mafé, Juan J.; Planelles, Beatriz; Asensio, Santos; Cerezal, Jorge; Inda, María-del-Mar; Lacueva, Javier; Esteban, Maria-Dolores; Hernández, Luis; Martín, Concepción; Baschwitz, Benno

    2017-01-01

    Background Video-assisted thoracic surgery (VATS) emerged as a minimally invasive surgery for diseases in the field of thoracic surgery. We herein reviewed our experience on thoracoscopic lobectomy for early lung cancer and evaluated Health System use. Methods A cost-effectiveness study was performed comparing VATS vs. open thoracic surgery (OPEN) for lung cancer patients. Demographic data, tumor localization, dynamic pulmonary function tests [forced vital capacity (FVC), forced expiratory volume in one second (FEV1), diffusion capacity (DLCO) and maximal oxygen uptake (VO2max)], surgical approach, postoperative details, and complications were recorded and analyzed. Results One hundred seventeen patients underwent lung resection by VATS (n=42, 36%; age: 63±9 years old, 57% males) or OPEN (n=75, 64%; age: 61±11 years old, 73% males). Pulmonary function tests decreased just after surgery with a parallel increasing tendency during first 12 months. VATS group tended to recover FEV1 and FVC quicker with significantly less clinical and post-surgical complications (31% vs. 53%, P=0.015). Costs including surgery and associated hospital stay, complications and costs in the 12 months after surgery were significantly lower for VATS (P<0.05). Conclusions The VATS approach surgery allowed earlier recovery at a lower cost than OPEN with a better cost-effectiveness profile. PMID:28932560

  18. Dam removal increases American eel abundance in distant headwater streams

    USGS Publications Warehouse

    Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.

    2012-01-01

    American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (<300 mm TL). We hypothesize that restoring connectivity to headwater streams could increase eel population growth rates by increasing female eel numbers and fecundity. This study demonstrated that dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

  19. Does the use of efficacy or effectiveness evidence in cost-effectiveness analysis matter?

    PubMed

    Dilokthornsakul, Piyameth; Chaiyakunapruk, Nathorn; Campbell, Jonathan D

    2017-01-02

    To test the association of clinical evidence type, efficacy-based or effectiveness-based ("E"), versus whether or not asthma interventions' cost-effectiveness findings are favorable. We conducted a systematic review of PubMed, EMBASE, Tufts CEA registry, Cochrane CENTRAL, and the UK National Health Services Economic Evaluation Database from 2009 to 2014. All cost-effectiveness studies evaluating asthma medication(s) were included. Clinical evidence type, "E," was classified as efficacy-based if the evidence was from an explanatory randomized controlled trial(s) or meta-analysis, while evidence from pragmatic trial(s) or observational study(s) was classified as effectiveness-based. We defined three times the World Health Organization cost-effectiveness willingness-to-pay (WTP) threshold or less as a favorable cost-effectiveness finding. Logistic regression tested the likelihood of favorable versus unfavorable cost-effectiveness findings against the type of "E." 25 cost-effectiveness studies were included. Ten (40.0%) studies were effectiveness-based, yet 15 (60.0%) studies were efficacy-based. Of 17 studies using endpoints that could be compared to WTP threshold, 7 out of 8 (87.5%) effectiveness-based studies yielded favorable cost-effectiveness results, whereas 4 out of 9 (44.4%) efficacy-based studies yielded favorable cost-effectiveness results. The adjusted odds ratio was 15.12 (95% confidence interval; 0.59 to 388.75) for effectiveness-based versus efficacy-based achieving favorable cost-effectiveness findings. More asthma cost-effectiveness studies used efficacy-based evidence. Studies using effectiveness-based evidence trended toward being more likely to disseminate favorable cost-effective findings than those using efficacy. Health policy decision makers should pay attention to the type of clinical evidence used in cost-effectiveness studies for accurate interpretation and application.

  20. Effect of Ambipolar Diffusion on Ion Abundances in Contracting Protostellar Cores

    NASA Astrophysics Data System (ADS)

    Ciolek, Glenn E.; Mouschovias, Telemachos Ch.

    1998-09-01

    Numerical simulations and analytical solutions have established that ambipolar diffusion can reduce the dust-to-gas ratio in magnetically and thermally supercritical cores during the epoch of core formation. We study the effect that this has on the ion chemistry in contracting protostellar cores and present a simplified analytical method that allows one to calculate the ion power-law exponent k (≡d ln ni/d ln nn, where ni and nn are the ion and neutral densities, respectively) as a function of core density. We find that, as in earlier numerical simulations, no single value of k can adequately describe the ion abundance for nn <~ 109 cm-3, a result that is contrary to the ``canonical'' value of k = 1/2 found in previous static equilibrium chemistry calculations and often used to study the effect of ambipolar diffusion in interstellar clouds. For typical cloud and grain parameters, reduction of the abundance of grains results in k > 1/2 during the core formation epoch (densities <~105 cm-3). As a consequence, observations of the degree of ionization in cores could be used, in principle, to determine whether ambipolar diffusion is responsible for core formation in interstellar molecular clouds. For densities >>105 cm-3, k is generally <<1/2.

  1. Meta-analysis: abundance, behavior, and hydraulic energy shape biotic effects on sediment transport in streams.

    PubMed

    Albertson, L K; Allen, D C

    2015-05-01

    An increasing number of studies have emphasized the need to bridge the disciplines of ecology and geomorphology. A large number of case studies show that organisms can affect erosion, but a comprehensive understanding of biological impacts on sediment transport conditions is still lacking. We use meta-analysis to synthesize published data to quantify the effects of the abundance, body size, and behavior of organisms on erosion in streams. We also explore the influence of current velocity, discharge, and sediment grain size on the strength of biotic effects on erosion. We found that species that both increase erosion (destabilizers) and decrease erosion (stabilizers) can alter incipient sediment motion, sediment suspension, and sediment deposition above control conditions in which the organisms were not present. When abundance was directly manipulated, these biotic effects were consistently stronger in the higher abundance treatment, increasing effect sizes by 66%. Per capita effect size and per capita biomass were also consistently positively correlated. Fish and crustaceans were the most studied organisms, but aquatic insects increased the effect size by 550 x compared to other types of organisms after accounting for biomass. In streams with lower discharge and smaller grain sizes, we consistently found stronger biotic effects. Taken collectively, these findings provide synthetic evidence that biology can affect physical processes in streams, and these effects can be mediated by hydraulic energy. We suggest that future studies focus on understudied organisms, such as biofilms, conducting experiments under realistic field conditions, and developing hypotheses for the effect of biology on erosion and velocity currents in the context of restoration to better understand the forces that mediate physical disturbances in stream ecosystems.

  2. Dynamic Programming and Error Estimates for Stochastic Control Problems with Maximum Cost

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bokanowski, Olivier, E-mail: boka@math.jussieu.fr; Picarelli, Athena, E-mail: athena.picarelli@inria.fr; Zidani, Hasnaa, E-mail: hasnaa.zidani@ensta.fr

    2015-02-15

    This work is concerned with stochastic optimal control for a running maximum cost. A direct approach based on dynamic programming techniques is studied leading to the characterization of the value function as the unique viscosity solution of a second order Hamilton–Jacobi–Bellman (HJB) equation with an oblique derivative boundary condition. A general numerical scheme is proposed and a convergence result is provided. Error estimates are obtained for the semi-Lagrangian scheme. These results can apply to the case of lookback options in finance. Moreover, optimal control problems with maximum cost arise in the characterization of the reachable sets for a system ofmore » controlled stochastic differential equations. Some numerical simulations on examples of reachable analysis are included to illustrate our approach.« less

  3. Systematic Review of the Cost and Cost-Effectiveness of Rapid Endovascular Therapy for Acute Ischemic Stroke.

    PubMed

    Sevick, Laura K; Ghali, Sarah; Hill, Michael D; Danthurebandara, Vishva; Lorenzetti, Diane L; Noseworthy, Tom; Spackman, Eldon; Clement, Fiona

    2017-09-01

    Rapid endovascular therapy (EVT) is an emerging treatment option for acute ischemic stroke. Several economic evaluations have been published examining the cost-effectiveness of EVT, and many international bodies are currently making adoption decisions. The objective of this study was to establish the cost-effectiveness of EVT for ischemic stroke patients and to synthesize all the publicly available economic literature. A systematic review of the published literature was conducted to identify economic evaluations and cost analyses of EVT for acute ischemic stroke patients. Systematic review best practices were followed, and study quality was assessed. Four-hundred sixty-three articles were identified from electronic databases. After deduplication, abstract review, and full-text review, 17 studies were included. Seven of the studies were cost analyses, and 10 were cost-effectiveness studies. Generally, the cost analyses reported on the cost of the approach/procedure or the hospitalization costs associated with EVT. All of the cost-effectiveness studies reported a cost per quality-adjusted life year as the primary outcomes. Studies varied in regards to the costs considered, the perspective adopted, and the time horizon used. All the studies reported a cost per quality-adjusted life year of <$50 000 as the primary outcome. There is a robust body of evidence for the cost and cost-effectiveness of EVT. The cost analyses suggested that although EVT was associated with higher costs, it also resulted in improved patient outcomes. From the cost-effectiveness studies, EVT seems to be good value for money when a threshold of $50 000 per quality-adjusted life year gained is adopted. © 2017 American Heart Association, Inc.

  4. Cost-effectiveness and cost utility analysis of three pneumococcal conjugate vaccines in children of Peru.

    PubMed

    Gomez, Jorge Alberto; Tirado, Juan Carlos; Navarro Rojas, Aldo Amador; Castrejon Alba, Maria Mercedes; Topachevskyi, Oleksandr

    2013-10-30

    The clinical and economic burden associated with invasive and non-invasive pneumococcal and non-typeable Haemophilus influenzae (NTHi) diseases is substantial in the Latin America and Caribbean region, where pneumococcal vaccines have only been introduced to a few countries. This study analyzed the cost-effectiveness and cost utility of three different pneumococcal conjugate vaccines (PCVs) for Peru. A Markov model that simulated the disease processes in a birth cohort over a lifetime, within 1,128 month cycles was used to evaluate the cost-effectiveness of 10-valent pneumococcal NTHi protein D conjugate vaccine (PHiD-CV) and 7- and 13-valent PCVs (PCV-7 and PCV-13). Expected quality-adjusted life years (QALYs), cost-savings and incremental cost-effectiveness ratios (ICERs) were calculated. Without vaccination, pneumonia was associated with the greatest health economic burden (90% of QALYs lost and 63% of lifetime direct medical costs); while acute otitis media (AOM) was responsible for 1% of QALYs lost and 25% of direct medical costs. All vaccines were predicted to be cost-effective for Peru, with PHiD-CV being most cost-effective. PHiD-CV was predicted to generate 50 more QALYs gained and required a reduced investment (-US$ 3.4 million) versus PCV-13 (discounted data), and was therefore dominant and cost saving. The probabilistic sensitivity analysis showed that PHiD-CV generated more QALYs gained at a reduced cost than PCV-13 in 84% of the simulations and less QALYs gains at a reduced cost in 16%. Additional scenarios using different assumptions on vaccine efficacies based on previous evidence were explored, but no significant change in the overall cost-effective results were observed. The results of this modeling study predict that PCVs are likely to be a cost-effective strategy to help relieve the epidemiological and economic burden associated with pediatric pneumococcal and NTHi diseases for Peru. PHiD-CV is likely to be a dominant (better health gains at a

  5. Effects of microhabitat and land use on stream salamander abundance in the southwest Virginia coalfields

    USGS Publications Warehouse

    Sweeten, Sara E.; Ford, W. Mark

    2015-01-01

    Large-scale land uses such as residential wastewater discharge and coal mining practices, particularly surface coal extraction and associated valley fills, are of particular ecological concern in central Appalachia. Identification and quantification of both alterations across scales are a necessary first-step to mitigate negative consequences to biota. In central Appalachian headwater streams absent of fish, salamanders are the dominant, most abundant vertebrate predator providing a significant intermediate trophic role. Stream salamander species are considered to be sensitive to aquatic stressors and environmental alterations, and past research has shown linkages among microhabitat parameters, large-scale land use such as urbanization and logging with salamander abundances. However, little is known about these linkages in the coalfields of central Appalachia. In the summer of 2013, we visited 70 sites (sampled three times each) in the southwest Virginia coalfields to survey salamanders and quantify stream and riparian microhabitat parameters. Using an information-theoretic framework we compared the effects of microhabitat and large-scale land use on salamander abundances. Our findings indicate that dusky salamander (Desmognathus spp.) abundances are more correlated to microhabitat parameters such as canopy cover than to subwatershed land uses. Brook salamander (Eurycea spp.) abundances show strong negative associations to the suspended sediments and stream substrate embeddedness. Neither Desmognathus spp. nor Eurycea spp. abundances were influenced by water conductivity. These suggest protection or restoration of riparian habitats and erosion control is an important conservation component for maintaining stream salamanders in the mined landscapes of central Appalachia.

  6. Cost-effective hydrocele ablation.

    PubMed

    Fracchia, J A; Armenakas, N A; Kohan, A D

    1998-03-01

    The surgical repair of hydroceles can be relatively expensive in some cases in terms of costs and initial limitation of activity. We ascertain whether aspiration and sclerotherapy of hydroceles is a safe, efficient, cost-effective treatment modality in select patients. In 47 patients 51 hydroceles were treated in the office with aspiration and instillation of a sclerosing solution based on a sodium tetradecyl sulfate preparation. One treatment was done in 14 cases and 2 in the remainder. Medicare data for 1995 were used for charge analysis. The overall success rate was 61% (34 of 51 cases) with success defined as no perceptible ipsilateral scrotal fluid reaccumulation on palpation by a physician and complete patient satisfaction. The failure rate was 39% (17 cases) with failure defined as perceptible ipsilateral scrotal fluid reaccumulation on palpation by a physician and/or patient dissatisfaction. The charge differential of surgery versus aspiration and sclerotherapy was greater than 9:1. The aspiration and sclerotherapy technique that we used appears to be an efficacious, safe, cost-effective treatment modality in select patients with idiopathic hydroceles.

  7. Clonal growth and plant species abundance

    PubMed Central

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-01-01

    Background and Aims Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf–height–seed) traits and by actual performance in the botanical garden. Methods Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area – height – seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. Key Results After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Conclusions Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially

  8. Impacts of large herbivorous mammals on bird diversity and abundance in an African savanna.

    PubMed

    Ogada, D L; Gadd, M E; Ostfeld, R S; Young, T P; Keesing, F

    2008-05-01

    Large native mammals are declining dramatically in abundance across Africa, with strong impacts on both plant and animal community dynamics. However, the net effects of this large-scale loss in megafauna are poorly understood because responses by several ecologically important groups have not been assessed. We used a large-scale, replicated exclusion experiment in Kenya to investigate the impacts of different guilds of native and domestic large herbivores on the diversity and abundance of birds over a 2-year period. The exclusion of large herbivorous native mammals, including zebras (Equus burchelli), giraffes (Giraffa camelopardalis), elephants (Loxodonta africana), and buffalos (Syncerus caffer), increased the diversity of birds by 30%. Most of this effect was attributable to the absence of elephants and giraffes; these megaherbivores reduced both the canopy area of subdominant woody vegetation and the biomass of ground-dwelling arthropods, and both of these factors were good predictors of the diversity of birds. The canopy area of subdominant trees was positively correlated with the diversity of granivorous birds. The biomass of ground-dwelling arthropods was positively correlated with the diversity of insectivorous birds. Our results suggest that most native large herbivores are compatible with an abundant and diverse bird fauna, as are cattle if they are at a relatively low stocking rate. Future research should focus on determining the spatial arrangements and densities of megaherbivores that will optimize both megaherbivore abundance and bird diversity.

  9. Stellar Oxygen Abundances

    NASA Astrophysics Data System (ADS)

    King, Jeremy

    1994-04-01

    This dissertation addresses several issues concerning stellar oxygen abundances. The 7774 {\\AA} O I triplet equivalent widths of Abia & Rebolo [1989, AJ, 347, 186] for metal-poor dwarfs are found to be systematically too high. I also argue that current effective temperatures used in halo star abundance studies may be ~150 K too low. New color-Teff relations are derived for metal-poor stars. Using the revised Teff values and improved equivalent widths for the 7774A O I triplet, the mean [O/Fe] ratio for a handful of halo stars is found to be +0.52 with no dependence on Teff or [Fe/H]. Possible cosmological implications of the hotter Teff scale are discussed along with additional evidence supporting the need for a higher temperature scale for metal-poor stars. Our Teff scale leads to a Spite Li plateau value of N(Li)=2.28 +/- 0.09. A conservative minimal primordial value of N(Li)=2.35 is inferred. If errors in the observations and models are considered, consistency with standard models of Big Bang nucleosynthesis is still achieved with this larger Li abundance. The revised Teff scale raises the observed B/Be ratio of HD 140283 from 10 to 12, making its value more comfortably consistent with the production of the observed B and Be by ordinary spallation. Our Teff values are found to be in good agreement with values predicted from both the Victoria and Yale isochrone color-Teff relations. Thus, it appears likely that no changes in globular cluster ages would result. Next, we examine the location of the break in the [O/Fe] versus [Fe/H] plane in a quantitative fashion. Analysis of a relatively homogeneous data set does not favor any unique break point in the range -1.7 /= -3), in agreement with the new results for halo dwarfs. We find that the gap in the observed [O/H] distribution, noted by Wheeler et al

  10. Emotional effects of dynamic textures

    PubMed Central

    Toet, Alexander; Henselmans, Menno; Lucassen, Marcel P; Gevers, Theo

    2011-01-01

    This study explores the effects of various spatiotemporal dynamic texture characteristics on human emotions. The emotional experience of auditory (eg, music) and haptic repetitive patterns has been studied extensively. In contrast, the emotional experience of visual dynamic textures is still largely unknown, despite their natural ubiquity and increasing use in digital media. Participants watched a set of dynamic textures, representing either water or various different media, and self-reported their emotional experience. Motion complexity was found to have mildly relaxing and nondominant effects. In contrast, motion change complexity was found to be arousing and dominant. The speed of dynamics had arousing, dominant, and unpleasant effects. The amplitude of dynamics was also regarded as unpleasant. The regularity of the dynamics over the textures' area was found to be uninteresting, nondominant, mildly relaxing, and mildly pleasant. The spatial scale of the dynamics had an unpleasant, arousing, and dominant effect, which was larger for textures with diverse content than for water textures. For water textures, the effects of spatial contrast were arousing, dominant, interesting, and mildly unpleasant. None of these effects were observed for textures of diverse content. The current findings are relevant for the design and synthesis of affective multimedia content and for affective scene indexing and retrieval. PMID:23145257

  11. Cost-Effective Marine Protection - A Pragmatic Approach

    PubMed Central

    Oinonen, Soile; Hyytiäinen, Kari; Ahlvik, Lassi; Laamanen, Maria; Lehtoranta, Virpi; Salojärvi, Joona; Virtanen, Jarno

    2016-01-01

    This paper puts forward a framework for probabilistic and holistic cost-effectiveness analysis to provide support in selecting the least-cost set of measures to reach a multidimensional environmental objective. Following the principles of ecosystem-based management, the framework includes a flexible methodology for deriving and populating criteria for effectiveness and costs and analyzing complex ecological-economic trade-offs under uncertainty. The framework is applied in the development of the Finnish Programme of Measures (PoM) for reaching the targets of the EU Marine Strategy Framework Directive (MSFD). The numerical results demonstrate that substantial cost savings can be realized from careful consideration of the costs and multiple effects of management measures. If adopted, the proposed PoM would yield improvements in the state of the Baltic Sea, but the overall objective of the MSFD would not be reached by the target year of 2020; for various environmental and administrative reasons, it would take longer for most measures to take full effect. PMID:26751965

  12. Helping the Noncompliant Child: An Assessment of Program Costs and Cost-Effectiveness.

    PubMed

    Honeycutt, Amanda A; Khavjou, Olga A; Jones, Deborah J; Cuellar, Jessica; Forehand, Rex L

    2015-02-01

    Disruptive behavior disorders (DBD) in children can lead to delinquency in adolescence and antisocial behavior in adulthood. Several evidence-based behavioral parent training (BPT) programs have been created to treat early onset DBD. This paper focuses on one such program, Helping the Noncompliant Child (HNC), and provides detailed cost estimates from a recently completed pilot study for the HNC program. The study also assesses the average cost-effectiveness of the HNC program by combining program cost estimates with data on improvements in child participants' disruptive behavior. The cost and effectiveness estimates are based on implementation of HNC with low-income families. Investigators developed a Microsoft Excel-based costing instrument to collect data from therapists on their time spent delivering the HNC program. The instrument was designed using an activity-based costing approach, where each therapist reported program time by family, by date, and for each skill that the family was working to master. Combining labor and non-labor costs, it is estimated that delivering the HNC program costs an average of $501 per family from a payer perspective. It also costs an average of $13 to improve the Eyberg Child Behavior Inventory intensity score by 1 point for children whose families participated in the HNC pilot program. The cost of delivering the HNC program appears to compare favorably with the costs of similar BPT programs. These cost estimates are the first to be collected systematically and prospectively for HNC. Program managers may use these estimates to plan for the resources needed to fully implement HNC.

  13. The determinants of cost-effectiveness potential: an historical perspective on lipid-lowering therapies.

    PubMed

    Refoios Camejo, Rodrigo; McGrath, Clare; Miraldo, Marisa; Rutten, Frans

    2013-05-01

    %, contracting from 0.36 QALYs to 0.08 QALYs, which resulted in a saving of approximately 15 % of the costs related to cardiovascular events. The price of the drug mix used in the management of high blood cholesterol varied considerably across the years: the weighted average monthly price (in year 2007 values) started at approximately £14, peaked around £26 and progressively decreased to its minimum at £6.85 in 2010. As a consequence, the maximum price allowed by current cost-effectiveness rules for a new technology achieving the clinical target was found to decrease by a minimum of 80 % between 1990 and 2010. The analysis supports the hypothesis that the potential for cost effectiveness of new therapies is dependent on factors specific to each disease area and furthermore to sub-populations within disease areas. Despite a clinical need still existing, the results suggest that no more technologies are likely to be developed in certain disease areas based on their low perceived cost-effectiveness potential. This occurs without considering the immediate and future value of the effectiveness lost, which may depend on the technical difficulty of materializing future advancements, and ignores the permanent character of such a decision. The analysis suggests that a single, static and arbitrary cost-effectiveness threshold may not be sufficient to capture the drug-development dynamics occurring at the disease level and successfully direct research to the disease areas that are most valued by society.

  14. System Dynamics Modeling of Households' Electricity Consumption and Cost-Income Ratio: a Case Study of Latvia

    NASA Astrophysics Data System (ADS)

    Bariss, Uldis; Bazbauers, Gatis; Blumberga, Andra; Blumberga, Dagnija

    2017-11-01

    Increased energy efficiency of the building sector is high on the list of priorities for energy policy since better energy efficiency would help to reduce impact on climate change and increase security of energy supply. One aim of the present study was to find a relative effect of growth of demand for energy services due to changes in income, energy consumption per unit of demand due to technological development, changes in electricity price and household income on household electricity consumption in Latvia. The method applied included system dynamics modeling and data from a household survey regarding the relationship between electricity saving activities and the electricity cost-income ratio. The results revealed that, in direct contrast to the expected, a potential reduction of the electricity consumption is rather insensitive to electricity price and electricity cost-income ratio, and that the efficiency of technologies could be the main drivers for future electricity savings. The results suggest that support to advancement of technologies and faster replacement of inefficient ones rather than influencing the energy price could be effective energy policy measures. The model, developed in the study could be used in similar assessments in other countries.

  15. Using Cost-Effectiveness Tests to Design CHP Incentive Programs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tidball, Rick

    This paper examines the structure of cost-effectiveness tests to illustrate how they can accurately reflect the costs and benefits of CHP systems. This paper begins with a general background discussion on cost-effectiveness analysis of DER and then describes how cost-effectiveness tests can be applied to CHP. Cost-effectiveness results are then calculated and analyzed for CHP projects in five states: Arkansas, Colorado, Iowa, Maryland, and North Carolina. Based on the results obtained for these five states, this paper offers four considerations to inform regulators in the application of cost-effectiveness tests in developing CHP programs.

  16. Spatiotemporal heterogeneity in prey abundance and vulnerability shapes the foraging tactics of an omnivore.

    PubMed

    Rayl, Nathaniel D; Bastille-Rousseau, Guillaume; Organ, John F; Mumma, Matthew A; Mahoney, Shane P; Soulliere, Colleen E; Lewis, Keith P; Otto, Robert D; Murray, Dennis L; Waits, Lisette P; Fuller, Todd K

    2018-05-01

    Prey abundance and prey vulnerability vary across space and time, but we know little about how they mediate predator-prey interactions and predator foraging tactics. To evaluate the interplay between prey abundance, prey vulnerability and predator space use, we examined patterns of black bear (Ursus americanus) predation of caribou (Rangifer tarandus) neonates in Newfoundland, Canada using data from 317 collared individuals (9 bears, 34 adult female caribou, 274 caribou calves). During the caribou calving season, we predicted that landscape features would influence calf vulnerability to bear predation, and that bears would actively hunt calves by selecting areas associated with increased calf vulnerability. Further, we hypothesized that bears would dynamically adjust their foraging tactics in response to spatiotemporal changes in calf abundance and vulnerability (collectively, calf availability). Accordingly, we expected bears to actively hunt calves when they were most abundant and vulnerable, but switch to foraging on other resources as calf availability declined. As predicted, landscape heterogeneity influenced risk of mortality, and bears displayed the strongest selection for areas where they were most likely to kill calves, which suggested they were actively hunting caribou. Initially, the per-capita rate at which bears killed calves followed a type-I functional response, but as the calving season progressed and calf vulnerability declined, kill rates dissociated from calf abundance. In support of our hypothesis, bears adjusted their foraging tactics when they were less efficient at catching calves, highlighting the influence that predation phenology may have on predator space use. Contrary to our expectations, however, bears appeared to continue to hunt caribou as calf availability declined, but switched from a tactic of selecting areas of increased calf vulnerability to a tactic that maximized encounter rates with calves. Our results reveal that generalist

  17. Environmental DNA (eDNA) detects the invasive rusty crayfish Orconectes rusticus at low abundances.

    PubMed

    Dougherty, Matthew M; Larson, Eric R; Renshaw, Mark A; Gantz, Crysta A; Egan, Scott P; Erickson, Daniel M; Lodge, David M

    2016-06-01

    Early detection is invaluable for the cost-effective control and eradication of invasive species, yet many traditional sampling techniques are ineffective at the low population abundances found at the onset of the invasion process. Environmental DNA (eDNA) is a promising and sensitive tool for early detection of some invasive species, but its efficacy has not yet been evaluated for many taxonomic groups and habitat types.We evaluated the ability of eDNA to detect the invasive rusty crayfish Orconectes rusticus and to reflect patterns of its relative abundance, in upper Midwest, USA, inland lakes. We paired conventional baited trapping as a measure of crayfish relative abundance with water samples for eDNA, which were analysed in the laboratory with a qPCR assay. We modelled detection probability for O. rusticus eDNA using relative abundance and site characteristics as covariates and also tested the relationship between eDNA copy number and O. rusticus relative abundance.We detected O. rusticus eDNA in all lakes where this species was collected by trapping, down to low relative abundances, as well as in two lakes where trap catch was zero. Detection probability of O. rusticus eDNA was well predicted by relative abundance of this species and lake water clarity. However, there was poor correspondence between eDNA copy number and O. rusticus relative abundance estimated by trap catches. Synthesis and applications . Our study demonstrates a field and laboratory protocol for eDNA monitoring of crayfish invasions, with results of statistical models that provide guidance of sampling effort and detection probabilities for researchers in other regions and systems. We propose eDNA be included as a tool in surveillance for invasive or imperilled crayfishes and other benthic arthropods.

  18. 23 CFR 635.205 - Finding of cost effectiveness.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Finding of cost effectiveness. 635.205 Section 635.205... CONSTRUCTION AND MAINTENANCE Force Account Construction § 635.205 Finding of cost effectiveness. (a) It may be found cost effective for a State transportation department or county to undertake a federally financed...

  19. Coronae of Stars with Supersolar Elemental Abundances

    NASA Technical Reports Server (NTRS)

    Peretz, Uria; Behar, Ehud; Drake, Stephen A.

    2015-01-01

    Coronal elemental abundances are known to deviate from the photospheric values of their parent star, with the degree of deviation depending on the first ionization potential (FIP). This study focuses on the coronal composition of stars with supersolar photospheric abundances. We present the coronal abundances of six such stars: 11 LMi, iota Hor, HR 7291, tau Boo, and alpha Cen A and B. These stars all have high-statistics X-ray spectra, three of which are presented for the first time. The abundances we measured were obtained using the line-resolved spectra of the Reflection Grating Spectrometer (RGS) in conjunction with the higher throughput EPIC-pn camera spectra onboard the XMM-Newton observatory. A collisionally ionized plasma model with two or three temperature components is found to represent the spectra well. All elements are found to be consistently depleted in the coronae compared to their respective photospheres. For 11 LMi and tau Boo no FIP effect is present, while iota Hor, HR 7291, and alpha Cen A and B show a clear FIP trend. These conclusions hold whether the comparison is made with solar abundances or the individual stellar abundances. Unlike the solar corona, where low-FIP elements are enriched, in these stars the FIP effect is consistently due to a depletion of high-FIP elements with respect to actual photospheric abundances. A comparison with solar (instead of stellar) abundances yields the same fractionation trend as on the Sun. In both cases, a similar FIP bias is inferred, but different fractionation mechanisms need to be invoked.

  20. MEDIAN-BASED INCREMENTAL COST-EFFECTIVENESS RATIOS WITH CENSORED DATA

    PubMed Central

    Bang, Heejung; Zhao, Hongwei

    2016-01-01

    Cost-effectiveness is an essential part of treatment evaluation, in addition to effectiveness. In the cost-effectiveness analysis, a measure called the incremental cost-effectiveness ratio (ICER) is widely utilized, and the mean cost and the mean (quality-adjusted) life years have served as norms to summarize cost and effectiveness for a study population. Recently, the median-based ICER was proposed for complementary or sensitivity analysis purposes. In this paper, we extend this method when some data are censored. PMID:26010599

  1. Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird.

    PubMed

    Tomás, Gustavo; Merino, Santiago; Martínez-de la Puente, Josué; Moreno, Juan; Morales, Judith; Lobato, Elisa

    2008-05-01

    Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host-parasite associations.

  2. [Cost-effectiveness of oral cancer screening in Hungary].

    PubMed

    Vokó, Zoltán; Túri, Gergő; Zsólyom, Adriána

    2016-07-01

    The burden of oral cancer is high in Hungary. To study the cost-effectiveness of potential oral cancer screening in Hungary. Three strategies were compared: no introduction of screening, organized yearly screening for 40-year-old males in general medical practise, and opportunistic screening of high risk 40-year-old males in primary care. Local estimates of health utilities and costs of each health state and of the screening programmes were identified. The main outcomes were total costs, quality adjusted life years, and incremental cost-effectiveness ratios. Depending on the efficacy of the treatments of precancerous lesions and the participation rate, screening strategies are cost-effective over a 15-20 year time course. The opportunistic screening of high risk people is more cost-effective than the other strategies. Opportunistic screening of high risk people would be cost-effective in Hungary. The uncertainty about the efficacy of the treatments of precancerous lesions requires more research to support evidence based health policy making. Orv. Hetil., 2016, 157(29), 1161-1170.

  3. Incentives in the family II: behavioral dynamics and the evolution of non-costly signaling.

    PubMed

    Akçay, Erol

    2012-02-07

    In many biological and social interactions, individuals with private information have incentives to misrepresent their information. A prominent example is when offspring know their need or condition but the parents do not. Theory showed that signal costs can ensure truthful communication in such situations, but further studies have cast in doubt whether empirically measured costs are high enough to sustain honesty, and whether the costly signaling equilibrium represents a fitness advantage over non-signaling. Here, I tackle these issues with a model of signaling that takes place at the behavioral time-scale through dynamic responses of individuals to each other. I then embed this behavioral model in an evolutionary one that asks how the decision rules of the parent and offspring evolve in response to the trade-off between signal costs and the costs of provisioning. I find that a non-costly honest signaling equilibrium can evolve when relatedness between siblings is above a certain threshold. This threshold is lower when (i) offspring get satiated more quickly, (ii) the cost of provisioning to the parent escalates less rapidly, or (iii) the variation in offspring need is higher. These results provide a potential resolution to the apparent paradox of costly begging. I also discuss the relation between costly signaling and mechanism design theories. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Commentary: Demonstrating Cost-Effectiveness in Pediatric Psychology

    PubMed Central

    2014-01-01

    Objective Changes in the health care system and payment plans will likely require pediatric psychologists to illustrate the impact of their services. Cost-effectiveness analyses are one method of demonstrating the potential economic benefits of our services but are rarely used by pediatric psychologists. Method A hypothetical cost-effectiveness analysis was conducted, comparing the costs and outcomes between a behavioral adherence intervention and no intervention for youth with acute lymphoblastic leukemia. Results Results illustrate how pediatric psychologists can use cost-effectiveness analyses to demonstrate the economic impact of their work. Conclusions Efforts to conduct economic analyses could allow pediatric psychologists to advocate for their services. Implications and future directions are discussed. PMID:24752732

  5. THE CURIOUS CASE OF ELEMENTAL ABUNDANCE DIFFERENCES IN THE DUAL HOT JUPITER HOSTS WASP-94A AND B

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Teske, Johanna K.; Khanal, Sandhya; Ramírez, Ivan, E-mail: jteske@carnegiescience.edu

    Binary stars provide an ideal laboratory for investigating the potential effects of planet formation on stellar composition. Assuming that the stars formed in the same environment/from the same material, any compositional anomalies between binary components might indicate differences in how material was sequestered in planets, or accreted by the star in the process of planet formation. We present here a study of the elemental abundance differences between WASP-94A and B, a pair of stars that each host a hot Jupiter exoplanet. The two stars are very similar in spectral type (F8 and F9), and their ∼2700 au separation suggests that their protoplanetarymore » disks were likely not influenced by stellar interactions, but WASP-94Ab’s orbit—misaligned with the host star spin axis and likely retrograde—points toward a dynamically active formation mechanism, perhaps different from that of WASP-94Bb, which is not misaligned and has a nearly circular orbit. Based on our high-quality spectra and strictly relative abundance analysis, we detect a depletion of volatiles (∼−0.02 dex, on average) and enhancement of refractories (∼0.01 dex) in WASP-94A relative to B (standard errors are ∼0.005 dex). This is different from every other published case of binary host star abundances, in which either no significant abundance differences are reported or there is some degree of enhancement in all elements, including volatiles. Several scenarios that may explain the abundance trend are discussed, but none can be definitively accepted or rejected. Additional high-contrast imaging observations to search for companions that may be dynamically affecting the system, as well as a larger sample of binary host star studies, are needed to better understand the curious abundance trends we observe in WASP-94A and B.« less

  6. Cost minimisation analysis of provision of oxygen at home: are the Drug Tariff guidelines cost effective?

    PubMed Central

    Heaney, Liam G; McAllister, Denise; MacMahon, Joseph

    1999-01-01

    Objectives To determine the level of oxygen cylinder use at which it becomes more cost effective to provide oxygen by concentrator at home in Northern Ireland, and to examine potential cost savings if cylinder use above this level had been replaced by concentrator in 1996. Design Cost minimisation analysis. Setting Area health boards in Northern Ireland. Main outcome measures Cost effective cut off point for switch to provision of oxygen from cylinder to concentrator. Potential maximum and minimum savings in Northern Ireland (sensitivity analysis) owing to switch to more cost effective strategy on the basis of provision of cylinders in 1996. Results In Northern Ireland it is currently cost effective to provide oxygen by concentrator when the patient is using three or more cylinders per month independent of the duration of the prescription. More widespread use of concentrators at this level of provision is likely to lead to a cost saving. Conclusions The Drug Tariff prescribing guidelines, advocating that provision of oxygen by concentrator becomes cheaper when 21 cylinders are being used per month—are currently inaccurate in Northern Ireland. Regional health authorities should review their current arrangements for provision of oxygen at home and perform a cost analysis to determine at what level it becomes more cost effective to provide oxygen by concentrator. Key messagesThe current Drug Tariff prescribing guidelines are not cost effective for provision of oxygen at home in Northern IrelandIndividual prescriptions detailing frequency of usage and delivery costs should be recordedA switch to a more cost effective strategy is likely to result in a cost savingRegional health authorities should examinecurrent arrangements for provision of oxygen at home and should perform cost analyses PMID:10390453

  7. Effects of cost metric on cost-effectiveness of protected-area network design in urban landscapes.

    PubMed

    Burkhalter, J C; Lockwood, J L; Maslo, B; Fenn, K H; Leu, K

    2016-04-01

    A common goal in conservation planning is to acquire areas that are critical to realizing biodiversity goals in the most cost-effective manner. The way monetary acquisition costs are represented in such planning is an understudied but vital component to realizing cost efficiencies. We sought to design a protected-area network within a forested urban region that would protect 17 birds of conservation concern. We compared the total costs and spatial structure of the optimal protected-area networks produced using three acquisition-cost surrogates (area, agricultural land value, and tax-assessed land value). Using the tax-assessed land values there was a 73% and 78% cost savings relative to networks derived using area or agricultural land value, respectively. This cost reduction was due to the considerable heterogeneity in acquisition costs revealed in tax-assessed land values, especially for small land parcels, and the corresponding ability of the optimization algorithm to identify lower-cost parcels for inclusion that had equal value to our target species. Tax-assessed land values also reflected the strong spatial differences in acquisition costs (US$0.33/m(2)-$55/m(2)) and thus allowed the algorithm to avoid inclusion of high-cost parcels when possible. Our results add to a nascent but growing literature that suggests conservation planners must consider the cost surrogate they use when designing protected-area networks. We suggest that choosing cost surrogates that capture spatial- and size-dependent heterogeneity in acquisition costs may be relevant to establishing protected areas in urbanizing ecosystems. © 2015 Society for Conservation Biology.

  8. Cost-effectiveness of osteo-odonto keratoprosthesis in Singapore.

    PubMed

    Dong, Di; Tan, Anna; Mehta, Jodhbir S; Tan, Donald; Finkelstein, Eric Andrew

    2014-01-01

    To determine the long-term cost-effectiveness of osteo-odonto keratoprosthesis (OOKP) relative to no treatment among patients with end-stage corneal and ocular surface diseases in Singapore. Cost-effectiveness analysis based on data from a retrospective cohort study. From a health system perspective, we calculated the incremental cost-effectiveness ratio of OOKP treatment relative to no treatment over a 30-year horizon, based on data from a cohort of 23 patients who underwent OOKP surgery between 2004 and 2009 at Singapore National Eye Centre. Preoperative and postoperative vision-related quality-of-life values were estimated from patients' visual outcomes and were used to calculate the gain in quality-adjusted life years (QALYs) resulting from OOKP treatment. Unsubsidized costs for surgery, consultations, examinations, medications, follow-up visits, and treatments for complications were retrieved from patients' bills to estimate the total costs associated with OOKP treatment. Sensitivity analyses were conducted to test the robustness of the model. Over a 30-year period, OOKP treatment, compared with no treatment, improved QALYs by 3.991 among patients with end-stage corneal and ocular surface diseases at an additional cost of S$67 840 (US$55 150), resulting in an incremental cost-effectiveness ratio of S$17 000/QALY (US$13 820/QALY). Based on commonly cited cost-effectiveness benchmarks, the OOKP is a cost-effective treatment for patients with end-stage corneal and ocular surface diseases. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Preventing and Treating Peri-Implantitis: A Cost-Effectiveness Analysis.

    PubMed

    Schwendicke, Falk; Tu, Yu-Kang; Stolpe, Michael

    2015-09-01

    A large number of treatments for peri-implantitis are available, but their cost-effectiveness remains uncertain. This study evaluates the cost-effectiveness of preventing and treating peri-implantitis. A Markov model was constructed that followed each implant over 20 years. Supportive implant therapy (SIT) for managing peri-implant mucositis and preventing development of peri-implantitis was either provided or not. Risk of peri-implantitis was assumed to be affected by SIT and the patient's risk profile. If peri-implantitis occurred, 11 treatment strategies (non-surgical or surgical debridement alone or combined with adjunct therapies) were compared. Treatments and risk profiles determined disease progression. Modeling was performed based on systematically collected data. Primary outcomes were costs and proportion of lost implants, as assessed via Monte Carlo microsimulations. Not providing SIT and performing only non-surgical debridement was both least costly and least effective. The next best (more costly and effective) option was to provide SIT and perform surgical debridement (additional 0.89 euros per 1% fewer implants lost). The most effective option included bone grafts, membranes, and laser treatment (56 euros per 1%). For patients at high risk, the cost-effectiveness of SIT increased, whereas in low-risk groups, a cost-optimized strategy was cost-effective. Although clinical decision-making will be guided mainly by clinical condition, cost-effectiveness analyses might add another perspective. Based on these findings, an unambiguous comparative effectiveness ranking was not established. However, cost-effectiveness was predominantly determined by provision of SIT and initial treatment costs. Transferability of these findings to other healthcare systems needs further confirmation.

  10. Understanding Cost-Effectiveness of Energy Efficiency Programs

    EPA Pesticide Factsheets

    Discusses the five standard tests used to assess the cost-effectiveness of energy efficiency, how states are using these tests, and how the tests can be used to determine the cost-effectiveness of energy efficiency measures.

  11. An Evaluation of the AirCare Program Based on Cost-Benefit and Cost-Effectiveness Analyses

    ERIC Educational Resources Information Center

    Bi, Hsiaotao T.; Wang, Dianle

    2006-01-01

    A cost-benefit analysis of the AirCare program in the province of British Columbia on the basis of emissions cost factors from the literature showed a benefit outweighing the cost. Furthermore, a cost-effectiveness analysis comparing the AirCare program with a hybrid-car rebate program revealed that the AirCare program is more effective in…

  12. Cost-effectiveness and cost utility analysis of three pneumococcal conjugate vaccines in children of Peru

    PubMed Central

    2013-01-01

    Background The clinical and economic burden associated with invasive and non-invasive pneumococcal and non-typeable Haemophilus influenzae (NTHi) diseases is substantial in the Latin America and Caribbean region, where pneumococcal vaccines have only been introduced to a few countries. This study analyzed the cost-effectiveness and cost utility of three different pneumococcal conjugate vaccines (PCVs) for Peru. Methods A Markov model that simulated the disease processes in a birth cohort over a lifetime, within 1,128 month cycles was used to evaluate the cost-effectiveness of 10-valent pneumococcal NTHi protein D conjugate vaccine (PHiD-CV) and 7- and 13-valent PCVs (PCV-7 and PCV-13). Expected quality-adjusted life years (QALYs), cost-savings and incremental cost-effectiveness ratios (ICERs) were calculated. Results Without vaccination, pneumonia was associated with the greatest health economic burden (90% of QALYs lost and 63% of lifetime direct medical costs); while acute otitis media (AOM) was responsible for 1% of QALYs lost and 25% of direct medical costs. All vaccines were predicted to be cost-effective for Peru, with PHiD-CV being most cost-effective. PHiD-CV was predicted to generate 50 more QALYs gained and required a reduced investment (−US$ 3.4 million) versus PCV-13 (discounted data), and was therefore dominant and cost saving. The probabilistic sensitivity analysis showed that PHiD-CV generated more QALYs gained at a reduced cost than PCV-13 in 84% of the simulations and less QALYs gains at a reduced cost in 16%. Additional scenarios using different assumptions on vaccine efficacies based on previous evidence were explored, but no significant change in the overall cost-effective results were observed. Conclusions The results of this modeling study predict that PCVs are likely to be a cost-effective strategy to help relieve the epidemiological and economic burden associated with pediatric pneumococcal and NTHi diseases for Peru. PHiD-CV is likely

  13. Cost-effectiveness of antiplatelet drugs after percutaneous coronary intervention.

    PubMed

    Wisløff, Torbjørn; Atar, Dan

    2016-01-01

    Clopidogrel has, for long time, been accepted as the standard treatment for patients who have undergone a percutaneous coronary intervention (PCI). The introduction of prasugrel-and more recently, ticagrelor-has introduced a decision-making problem for clinicians and governments worldwide: to use the cheaper clopidogrel or the more effective, and also more expensive prasugrel or ticagrelor. We aim to give helpful contributions to this debate by analysing the cost-effectiveness of clopidogrel, prasugrel, and ticagrelor compared with each other. We modified a previously developed Markov model of cardiac disease progression. In the model, we followed up cohorts of patients who have recently had a PCI until 100 years or death. Possible events are revascularization, bleeding, acute myocardial infarction, and death. Our analysis shows that ticagrelor is cost-effective in 77% of simulations at an incremental cost-effectiveness ratio of €7700 compared with clopidogrel. Ticagrelor was also cost-effective against prasugrel at a cost-effectiveness ratio of €7800. Given a Norwegian cost-effectiveness threshold of €70 000, both comparisons appear to be clearly cost-effective in favour of ticagrelor. Ticagrelor is cost-effective compared with both clopidogrel and prasugrel for patients who have undergone a PCI.

  14. Cost-effectiveness analysis of total ankle arthroplasty.

    PubMed

    SooHoo, Nelson F; Kominski, Gerald

    2004-11-01

    There is renewed interest in total ankle arthroplasty as an alternative to ankle fusion in the treatment of end-stage ankle arthritis. Despite a lack of long-term data on the clinical outcomes associated with these implants, the use of ankle arthroplasty is expanding. The purpose of this cost-effectiveness analysis was to evaluate whether the currently available literature justifies the emerging use of total ankle arthroplasty. This study also identifies thresholds for the durability and function of ankle prostheses that, if met, would support more widespread dissemination of this new technology. A decision model was created for the treatment of ankle arthritis. The literature was reviewed to identify possible outcomes and their probabilities following ankle fusion and ankle arthroplasty. Each outcome was weighted for quality of life with use of a utility factor, and effectiveness was expressed in units of quality-adjusted life years. Gross costs were estimated from Medicare charge and reimbursement data for the relevant codes. The effect of the uncertainty of estimates of costs and effectiveness was assessed with sensitivity analysis. The reference case of our model assumed a ten-year duration of survival of the prosthesis, resulting in an incremental cost-effectiveness ratio for ankle arthroplasty of $18,419 per quality-adjusted life year gained. This reflects a gain of 0.52 quality-adjusted life years at a cost of $9578 when ankle arthroplasty is chosen over fusion. This ratio compares favorably with the cost-effectiveness of other medical and surgical interventions. Sensitivity analysis determined that the cost per quality-adjusted life year gained with ankle arthroplasty rises above $50,000 if the prosthesis is assumed to fail before seven years. Treatment options with ratios above $50,000 per quality-adjusted life year are commonly considered to have limited cost-effectiveness. This threshold is also crossed when the theoretical functional advantages of ankle

  15. [Screening for cancer - economic consideration and cost-effectiveness].

    PubMed

    Kjellberg, Jakob

    2014-06-09

    Cost-effectiveness analysis has become an accepted method to evaluate medical technology and allocate scarce health-care resources. Published decision analyses show that screening for cancer in general is cost-effective. However, cost-effectiveness analyses are only as good as the clinical data and the results are sensitive to the chosen methods and perspective of the analysis.

  16. The Cost-Effectiveness Analysis of Teleglaucoma Screening Device.

    PubMed

    Thomas, Sera; Hodge, William; Malvankar-Mehta, Monali

    2015-01-01

    Glaucoma is the leading cause of irreversible vision loss and costs the American economy $2.9 billion. Teleglaucoma remotely detects glaucoma improving access to ophthalmic care in rural areas. It helps manage glaucoma more efficiently to preserve vision and reduce healthcare costs. A cost-effectiveness analysis was conducted using healthcare provider or third-party payer perspective within rural Canada. The study population were patients at-risk of glaucoma which includes those with diabetes and/or hypertension, family history of glaucoma, adults older than 50 years, and concurrent ocular conditions in rural Alberta. Markov modelling was used to model glaucoma health states. Effectiveness was measured in Quality-Adjusted Life Years (QALYs) and costs were used in Canadian dollars. Using TreeAge Pro 2009, incremental cost-effectiveness ratios (ICER) were developed in dollars per QALYs. Deterministic and probabilistic sensitivity analyses were performed to assess the factors affecting cost-effectiveness. Teleglaucoma had a 20% increase in ophthalmologist-referral rate; it reduced patient travel times by 61 hours and physician wait times by 30% in comparison to in-person examination (standard of care). Teleglaucoma costs $872 per patient screened which was 80% less than in-person examination. Teleglaucoma had a greater incremental effectiveness providing an additional 0.12 QALY per patient examination. It was more sensitive (86.5%) and less specific (78.6%) than in-person examination. Teleglaucoma was more cost-effective than in-person examination with an ICER of-$27,460/QALY. This indicated that teleglaucoma will save $27, 460 for each additional QALY gained. Long term benefits showed teleglaucoma prevents 24% cases of glaucoma blindness after 30 years. Teleglaucoma demonstrated improved health outcomes, as well as, cost benefits. It increases access to ophthalmic care and improves healthcare service efficiency, specifically in rural areas. Teleglaucoma is more cost-effective

  17. Cost-effectiveness and Pricing of Antibacterial Drugs

    PubMed Central

    Verhoef, Talitha I; Morris, Stephen

    2015-01-01

    Growing resistance to antibacterial agents has increased the need for the development of new drugs to treat bacterial infections. Given increasing pressure on limited health budgets, it is important to study the cost-effectiveness of these drugs, as well as their safety and efficacy, to find out whether or not they provide value for money and should be reimbursed. In this article, we systematically reviewed 38 cost-effectiveness analyses of new antibacterial agents. Most studies showed the new antibacterial drugs were cost-effective compared to older generation drugs. Drug pricing is a complicated process, involving different stakeholders, and has a large influence on cost-effectiveness. Value-based pricing is a method to determine the price of a drug at which it can be cost-effective. It is currently unclear what the influence of value-based pricing will be on the prices of new antibacterial agents, but an important factor will be the definition of ‘value’, which as well as the impact of the drug on patient health might also include other factors such as wider social impact and the health impact of disease. PMID:25521641

  18. Cost-effectiveness and pricing of antibacterial drugs.

    PubMed

    Verhoef, Talitha I; Morris, Stephen

    2015-01-01

    Growing resistance to antibacterial agents has increased the need for the development of new drugs to treat bacterial infections. Given increasing pressure on limited health budgets, it is important to study the cost-effectiveness of these drugs, as well as their safety and efficacy, to find out whether or not they provide value for money and should be reimbursed. In this article, we systematically reviewed 38 cost-effectiveness analyses of new antibacterial agents. Most studies showed the new antibacterial drugs were cost-effective compared to older generation drugs. Drug pricing is a complicated process, involving different stakeholders, and has a large influence on cost-effectiveness. Value-based pricing is a method to determine the price of a drug at which it can be cost-effective. It is currently unclear what the influence of value-based pricing will be on the prices of new antibacterial agents, but an important factor will be the definition of 'value', which as well as the impact of the drug on patient health might also include other factors such as wider social impact and the health impact of disease. © 2015 The Authors. Chemical Biology & Drug Design Published by John Wiley & Sons Ltd.

  19. A systematic review of the cost and cost effectiveness of treatment for multidrug-resistant tuberculosis.

    PubMed

    Fitzpatrick, Christopher; Floyd, Katherine

    2012-01-01

    Around 0.4 million cases of multidrug-resistant tuberculosis (MDR-TB) occur each year. Only a small fraction of these cases are treated according to international guidelines. Evidence relevant to decisions about whether to scale-up treatment for MDR-TB includes cost and cost-effectiveness data. Up to 2010, no systematic review of this evidence has been available. Our objective was to conduct a systematic review of the cost and cost effectiveness of treatment for MDR-TB and synthesize the available data. We searched for papers published or prepared for publication in peer-review journals and grey literature using search terms in five languages: English, French, Portuguese, Russian and Spanish. From an initial set of 420 studies, four were included, from Peru, the Philippines, Estonia and Tomsk Oblast in the Russian Federation. Results on costs, effectiveness and cost effectiveness were extracted. Assessment of the quality of each economic evaluation was guided by two existing checklists around which there is broad consensus. Costs were adjusted to a common year of value (2005) to remove distortions caused by inflation, and calculated in two common currencies: $US and international dollars (I$), to standardize for purchasing power parity. Data from the four identified studies were then synthesized using probabilistic sensitivity analysis, to appraise the likely cost and cost effectiveness of MDR-TB treatment in other settings, relative to WHO benchmarks for assessing whether or not an intervention is cost effective. Best estimates are provided as means, with 5th and 95th percentiles of the distributions. The cost per patient for MDR-TB treatment in Estonia, Peru, the Philippines and Tomsk was $US10 880, $US2423, $US3613 and $US14 657, respectively. Best estimates of the cost per disability-adjusted life-year (DALY) averted were $US598 (I$960), $US163 (I$291), $US143 (I$255) and $US745 (I$1059), respectively. The main influences on costs were (i) the model of care

  20. Cost-effectiveness of pharmacological and psychosocial interventions for schizophrenia.

    PubMed

    Phanthunane, Pudtan; Vos, Theo; Whiteford, Harvey; Bertram, Melanie

    2011-05-13

    Information on cost-effectiveness of interventions to treat schizophrenia can assist health policy decision making, particularly given the lack of health resources in developing countries like Thailand. This study aims to determine the optimal treatment package, including drug and non-drug interventions, for schizophrenia in Thailand. A Markov model was used to evaluate the cost-effectiveness of typical antipsychotics, generic risperidone, olanzapine, clozapine and family interventions. Health outcomes were measured in disability adjusted life years. We evaluated intervention benefit by estimating a change in disease severity, taking into account potential side effects. Intervention costs included outpatient treatment costs, hospitalization costs as well as time and travel costs of patients and families. Uncertainty was evaluated using Monte Carlo simulation. A sensitivity analysis of the expected range cost of generic risperidone was undertaken. Generic risperidone is more cost-effective than typicals if it can be produced for less than 10 baht per 2 mg tablet. Risperidone was the cheapest treatment with higher drug costs offset by lower hospital costs in comparison to typicals. The most cost-effective combination of treatments was a combination of risperidone (dominant intervention). Adding family intervention has an incremental cost-effectiveness ratio of 1,900 baht/DALY with a 100% probability of a result less than a threshold for very cost-effective interventions of one times GDP or 110,000 baht per DALY. Treating the most severe one third of patients with clozapine instead of risperidone had an incremental cost-effectiveness ratio of 320,000 baht/DALY with just over 50% probability of a result below three times GDP per capita. There are good economic arguments to recommend generic risperidone as first line treatment in combination with family intervention. As the uncertainty interval indicates the addition of clozapine may be dominated and there are serious

  1. Costs and cost-effectiveness of vector control in Eritrea using insecticide-treated bed nets.

    PubMed

    Yukich, Joshua O; Zerom, Mehari; Ghebremeskel, Tewolde; Tediosi, Fabrizio; Lengeler, Christian

    2009-03-30

    While insecticide-treated nets (ITNs) are a recognized effective method for preventing malaria, there has been an extensive debate in recent years about the best large-scale implementation strategy. Implementation costs and cost-effectiveness are important elements to consider when planning ITN programmes, but so far little information on these aspects is available from national programmes. This study uses a standardized methodology, as part of a larger comparative study, to collect cost data and cost-effectiveness estimates from a large programme providing ITNs at the community level and ante-natal care facilities in Eritrea. This is a unique model of ITN implementation fully integrated into the public health system. Base case analysis results indicated that the average annual cost of ITN delivery (2005 USD 3.98) was very attractive when compared with past ITN delivery studies at different scales. Financing was largely from donor sources though the Eritrean government and net users also contributed funding. The intervention's cost-effectiveness was in a highly attractive range for sub-Saharan Africa. The cost per DALY averted was USD 13 - 44. The cost per death averted was USD 438-1449. Distribution of nets coincided with significant increases in coverage and usage of nets nationwide, approaching or exceeding international targets in some areas. ITNs can be cost-effectively delivered at a large scale in sub-Saharan Africa through a distribution system that is highly integrated into the health system. Operating and sustaining such a system still requires strong donor funding and support as well as a functional and extensive system of health facilities and community health workers already in place.

  2. Effects of Bubble-Mediated Processes on Nitrous Oxide Dynamics in Denitrifying Bioreactors

    NASA Astrophysics Data System (ADS)

    McGuire, P. M.; Falk, L. M.; Reid, M. C.

    2017-12-01

    To mitigate groundwater and surface water impacts of reactive nitrogen (N), agricultural and stormwater management practices can employ denitrifying bioreactors (DNBs) as low-cost solutions for enhancing N removal. Due to the variable nature of hydrologic events, DNBs experience dynamic flows which can impact physical and biological processes within the reactors and affect performance. A particular concern is incomplete denitrification, which can release the potent greenhouse gas nitrous oxide (N2O) to the atmosphere. This study aims to provide insight into the effects of varying hydrologic conditions upon the operation of DNBs by disentangling abiotic and biotic controls on denitrification and N2O dynamics within a laboratory-scale bioreactor. We hypothesize that under transient hydrologic flows, rising water levels lead to air entrapment and bubble formation within the DNB porous media. Mass transfer of oxygen (O2) between trapped gas and liquid phases creates aerobic microenvironments that can inhibit N2O reductase (NosZ) enzymes and lead to N2O accumulation. These bubbles also retard N2O transport and make N2O unavailable for biological reduction, further enhancing atmospheric fluxes when water levels fall. The laboratory-scale DNB permits measurements of longitudinal and vertical profiles of dissolved constituents as well as trace gas concentrations in the reactor headspace. We describe a set of experiments quantifying denitrification pathway biokinetics under steady-state and transient hydrologic conditions and evaluate the role of bubble-mediated processes in enhancing N2O accumulation and fluxes. We use sulfur hexafluoride and helium as dissolved gas tracers to examine the impact of bubble entrapment upon retarded gas transport and enhanced trace gas fluxes. A planar optode sensor within the bioreactor provides near-continuous 2-D profiles of dissolved O2 within the bioreactor and allows for identification of aerobic microenvironments. We use qPCR to

  3. Preliminary CALET Ultra Heavy Cosmic Ray Abundance Measurements

    NASA Astrophysics Data System (ADS)

    Rauch, Brian; CALET Collaboration

    2017-01-01

    The CALorimetric Electron Telescope (CALET) on the International Space Station (ISS) was launched August 19, 2015 and has been returning excellent data for over a year. The main calorimeter (CAL) on CALET measures the fluxes of high-energy electrons, nuclei and gamma rays. In addition to measuring the energy spectra of the more abundant cosmic-ray nuclei through 26Fe, CAL has the dynamic range to measure the abundances of the ultra-heavy (UH) cosmic-ray nuclei through 40Zr. In an anticipated 5 year mission on the ISS CALET will collect a UH data set with statistics comparable to that achieved with the first flight of the SuperTIGER balloon-borne instrument. The CALET space-based measurement has the advantage of not requiring corrections for atmospheric losses, and unlike other UH measurements the abundances of all nuclei from 1H through 40Zr are observed with the same instrument. We present preliminary CALET UH analysis results from the first year of operation. This research was supported by NASA at Washington University under Grant Number NNX11AE02G.

  4. Small-scale effects of thermal inflation on halo abundance at high-z, galaxy substructure abundance, and 21-cm power spectrum

    NASA Astrophysics Data System (ADS)

    Hong, Sungwook E.; Zoe, Heeseung; Ahn, Kyungjin

    2017-11-01

    We study the impact of thermal inflation on the formation of cosmological structures and present astrophysical observables which can be used to constrain and possibly probe the thermal inflation scenario. These are dark matter halo abundance at high redshifts, satellite galaxy abundance in the Milky Way, and fluctuation in the 21-cm radiation background before the epoch of reionization. The thermal inflation scenario leaves a characteristic signature on the matter power spectrum by boosting the amplitude at a specific wave number determined by the number of e-foldings during thermal inflation (N_{bc}), and strongly suppressing the amplitude for modes at smaller scales. For a reasonable range of parameter space, one of the consequences is the suppression of minihalo formation at high redshifts and that of satellite galaxies in the Milky Way. While this effect is substantial, it is degenerate with other cosmological or astrophysical effects. The power spectrum of the 21-cm background probes this impact more directly, and its observation may be the best way to constrain the thermal inflation scenario due to the characteristic signature in the power spectrum. The Square Kilometre Array (SKA) in phase 1 (SKA1) has sensitivity large enough to achieve this goal for models with N_{bc} ≳ 26 if a 10000-hr observation is performed. The final phase SKA, with anticipated sensitivity about an order of magnitude higher, seems more promising and will cover a wider parameter space.

  5. Forecasting the Cost-Effectiveness of Educational Incentives

    ERIC Educational Resources Information Center

    Abt, Clark C.

    1974-01-01

    A look at cost-effectiveness as the major characteristic for which to develop a forecasting method, because it encompasses concerns of most educators. It indicates relative costs and relative effectiveness, and provides a rational basis for optimal resource allocation. (Author)

  6. A review of cost-effectiveness, cost-containment and economics curricula in graduate medical education.

    PubMed

    Varkey, Prathibha; Murad, Mohammad H; Braun, Chad; Grall, Kristi J H; Saoji, Vivek

    2010-12-01

    Numerous studies performed over the last 30 years suggest that doctors have poor knowledge of the costs of medical care. In most graduate medical education programmes, trainees do not receive formal training in cost-effective medical practice. Comprehensive literature search of electronic bibliographic databases for articles that describe health economics, cost-containment and cost-effectiveness curricula in graduate medical education. Critical appraisal of the literature and qualitative description is presented. Heterogeneity of curricula precluded quantitative summary of data. We identified 40 articles that met the inclusion criteria for this review. Internal medicine residents were the targeted learners in 27 studies (68%); Family Medicine and Surgery residents were each targeted in five studies (13%); Rehabilitation, Paediatrics and Emergency Medicine residents were each targeted in one study. In general, the methodological quality of the included studies was poor to moderate and mostly targeted knowledge of health economics or cost-containment as opposed to targeting cost-effectiveness. In terms of describing the standard curricular components, studies sufficiently described the different educational strategies (e.g. didactics, interactive, experiential, self-directed) and the component of learner assessment, but lacked the description of other elements such as needs assessment and curriculum evaluation. Cost-effectiveness curricula in graduate medical education are lacking and clearly needed. © 2010 Blackwell Publishing Ltd.

  7. A Generic Simulation Model of the Relative Cost-Effectiveness of ICU Versus Step-Down (IMCU) Expansion.

    PubMed

    Mahmoudian-Dehkordi, Amin; Sadat, Somayeh

    2017-01-01

    Many jurisdictions are facing increased demand for intensive care. There are two long-term investment options: intensive care unit (ICU) versus step-down or intermediate care unit (IMCU) capacity expansion. Relative cost-effectiveness of the two investment strategies with regard to patient lives saved has not been studied to date. We expand a generic system dynamics simulation model of emergency patient flow in a typical hospital, populated with empirical evidence found in the medical and hospital administration literature, to estimate the long-term effects of expanding ICU versus IMCU beds on patient lives saved under a common assumption of 2.1% annual increase in hospital arrivals. Two alternative policies of expanding ICU by two beds versus introducing a two-bed IMCU are compared over a ten-year simulation period. Russel equation is used to calculate total cost of patients' hospitalization. Using two possible values for the ratio of ICU to IMCU cost per inpatient day and four possible values for the percentage of patients transferred from ICU to IMCU found in the literature, nine scenarios are compared against the baseline scenario of no capacity expansion. Expanding ICU capacity by two beds is demonstrated as the most cost-effective scenario with an incremental cost-effectiveness ratio of 3684 (US $) per life saved against the baseline scenario. Sensitivity analyses on the mortality rate of patients in IMCU, direct transfer of IMCU-destined patients to the ward upon completing required IMCU length of stay in the ICU, admission of IMCU patient to ICU, adding two ward beds, and changes in hospital size do not change the superiority of ICU expansion over other scenarios. In terms of operational costs, ICU beds are more cost effective for saving patients than IMCU beds. However, capital costs of setting up ICU versus IMCU beds should be considered for a complete economic analysis.

  8. The effectiveness and cost-effectiveness of a rural employer-based wellness program.

    PubMed

    Saleh, Shadi S; Alameddine, Mohamad S; Hill, Dan; Darney-Beuhler, Jessica; Morgan, Ann

    2010-01-01

    The cost-effectiveness of employer-based wellness programs has been previously investigated with favorable financial and nonfinancial outcomes being detected. However, these investigations have mainly focused on large employers in urban settings. Very few studies examined wellness programs offered in rural settings. This paper aims to explore the effectiveness and cost-effectiveness of a rural employer-based wellness program. Six rural employers were categorized into 3 groups: a control group and 2 intervention groups with varying degrees of wellness activities. Participants were asked to complete an annual health risk assessment (HRA) that addressed 16 wellness areas. At the conclusion of 4 years, HRA and effectiveness data were utilized to examine program effectiveness and combined with program costs to estimate cost-effectiveness. The "Coaching and Referral" group-the highest in intensity of participant engagement-exhibited superior improvement in several wellness areas and in percentage of employees with good health indicators compared to the control and the Trail Marker, lower-intensity intervention groups. However, the Trail Markers had more favorable cost-effectiveness ratios. Rural worksite wellness programs have shown great potential in their effectiveness and cost-effectiveness. Such programs need not be too aggressive, tedious, and costly to generate a favorable return for employers and funders. However, employers should be encouraged to experiment with different levels of wellness program intensities until a more favorable outcome can be realized.

  9. Rationale for cost-effective laboratory medicine.

    PubMed Central

    Robinson, A

    1994-01-01

    There is virtually universal consensus that the health care system in the United States is too expensive and that costs need to be limited. Similar to health care costs in general, clinical laboratory expenditures have increased rapidly as a result of increased utilization and inflationary trends within the national economy. Economic constraints require that a compromise be reached between individual welfare and limited societal resources. Public pressure and changing health care needs have precipitated both subtle and radical laboratory changes to more effectively use allocated resources. Responsibility for excessive laboratory use can be assigned primarily to the following four groups: practicing physicians, physicians in training, patients, and the clinical laboratory. The strategies to contain escalating health care costs have ranged from individualized physician education programs to government intervention. Laboratories have responded to the fiscal restraints imposed by prospective payment systems by attempting to reduce operational costs without adversely impacting quality. Although cost containment directed at misutilization and overutilization of existing services has conserved resources, to date, an effective cost control mechanism has yet to be identified and successfully implemented on a grand enough scale to significantly impact health care expenditures in the United States. PMID:8055467

  10. At what costs will screening with CT colonography be competitive? A cost-effectiveness approach.

    PubMed

    Lansdorp-Vogelaar, Iris; van Ballegooijen, Marjolein; Zauber, Ann G; Boer, Rob; Wilschut, Janneke; Habbema, J Dik F

    2009-03-01

    The costs of computed tomographic colonography (CTC) are not yet established for screening use. In our study, we estimated the threshold costs for which CTC screening would be a cost-effective alternative to colonoscopy for colorectal cancer (CRC) screening in the general population. We used the MISCAN-colon microsimulation model to estimate the costs and life-years gained of screening persons aged 50-80 years for 4 screening strategies: (i) optical colonoscopy; and CTC with referral to optical colonoscopy of (ii) any suspected polyp; (iii) a suspected polyp >or=6 mm and (iv) a suspected polyp >or=10 mm. For each of the 4 strategies, screen intervals of 5, 10, 15 and 20 years were considered. Subsequently, for each CTC strategy and interval, the threshold costs of CTC were calculated. We performed a sensitivity analysis to assess the effect of uncertain model parameters on the threshold costs. With equal costs ($662), optical colonoscopy dominated CTC screening. For CTC to gain similar life-years as colonoscopy screening every 10 years, it should be offered every 5 years with referral of polyps >or=6 mm. For this strategy to be as cost-effective as colonoscopy screening, the costs must not exceed $285 or 43% of colonoscopy costs (range in sensitivity analysis: 39-47%). With 25% higher adherence than colonoscopy, CTC threshold costs could be 71% of colonoscopy costs. Our estimate of 43% is considerably lower than previous estimates in literature, because previous studies only compared CTC screening to 10-yearly colonoscopy, where we compared to different intervals of colonoscopy screening.

  11. Cost Effectiveness Ratio: Evaluation Tool for Comparing the Effectiveness of Similar Extension Programs

    ERIC Educational Resources Information Center

    Jayaratne, K. S. U.

    2015-01-01

    Extension educators have been challenged to be cost effective in their educational programming. The cost effectiveness ratio is a versatile evaluation indicator for Extension educators to compare the cost of achieving a unit of outcomes or educating a client in similar educational programs. This article describes the cost effectiveness ratio and…

  12. Abundance of introduced species at home predicts abundance away in herbaceous communities

    USGS Publications Warehouse

    Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  13. Cost-effectiveness of Chlamydia antibody tests in subfertile women.

    PubMed

    Fiddelers, A A A; Land, J A; Voss, G; Kessels, A G H; Severens, J L

    2005-02-01

    For the evaluation of tubal function, Chlamydia antibody testing (CAT) has been introduced as a screening test. We compared six CAT screening strategies (five CAT tests and one combination of tests), with respect to their cost-effectiveness, by using IVF pregnancy rate as outcome measure. A decision analytic model was developed based on a source population of 1715 subfertile women. The model incorporates hysterosalpingography (HSG), laparoscopy and IVF. To calculate IVF pregnancy rates, costs, effects, cost-effectiveness and incremental costs per effect of the six different CAT screening strategies were determined. pELISA Medac turned out to be the most cost-effective CAT screening strategy (15 075 per IVF pregnancy), followed by MIF Anilabsystems (15 108). A combination of tests (pELISA Medac and MIF Anilabsystems; 15 127) did not improve the cost-effectiveness of the single strategies. Sensitivity analyses showed that the results are robust for changes in the baseline values of the model parameters. Only small differences were found between the screening strategies regarding the cost-effectiveness, although pELISA Medac was the most cost-effective strategy. Before introducing a particular CAT test into clinical practice, one should consider the effects and consequences of the entire screening strategy, instead of only the diagnostic accuracy of the test used.

  14. Cost-effectiveness of antiplatelet drugs after percutaneous coronary intervention

    PubMed Central

    Wisløff, Torbjørn; Atar, Dan

    2016-01-01

    Abstract Aims Clopidogrel has, for long time, been accepted as the standard treatment for patients who have undergone a percutaneous coronary intervention (PCI). The introduction of prasugrel—and more recently, ticagrelor—has introduced a decision-making problem for clinicians and governments worldwide: to use the cheaper clopidogrel or the more effective, and also more expensive prasugrel or ticagrelor. We aim to give helpful contributions to this debate by analysing the cost-effectiveness of clopidogrel, prasugrel, and ticagrelor compared with each other. Methods and results We modified a previously developed Markov model of cardiac disease progression. In the model, we followed up cohorts of patients who have recently had a PCI until 100 years or death. Possible events are revascularization, bleeding, acute myocardial infarction, and death. Our analysis shows that ticagrelor is cost-effective in 77% of simulations at an incremental cost-effectiveness ratio of €7700 compared with clopidogrel. Ticagrelor was also cost-effective against prasugrel at a cost-effectiveness ratio of €7800. Given a Norwegian cost-effectiveness threshold of €70 000, both comparisons appear to be clearly cost-effective in favour of ticagrelor. Conclusion Ticagrelor is cost-effective compared with both clopidogrel and prasugrel for patients who have undergone a PCI. PMID:29474586

  15. Cost-Effectiveness of Dengue Vaccination Programs in Brazil

    PubMed Central

    Shim, Eunha

    2017-01-01

    The first approved dengue vaccine, CYD-TDV, a chimeric, live-attenuated, tetravalent dengue virus vaccine, was recently licensed in 13 countries, including Brazil. In light of recent vaccine approval, we modeled the cost-effectiveness of potential vaccination policies mathematically based on data from recent vaccine efficacy trials that indicated that vaccine efficacy was lower in seronegative individuals than in seropositive individuals. In our analysis, we investigated several vaccination programs, including routine vaccination, with various vaccine coverage levels and those with and without large catch-up campaigns. As it is unclear whether the vaccine protects against infection or just against disease, our model incorporated both direct and indirect effects of vaccination. We found that in the presence of vaccine-induced indirect protection, the cost-effectiveness of dengue vaccination decreased with increasing vaccine coverage levels because the marginal returns of herd immunity decreases with vaccine coverage. All routine dengue vaccination programs that we considered were cost-effective, reducing dengue incidence significantly. Specifically, a routine dengue vaccination of 9-year-olds would be cost-effective when the cost of vaccination per individual is less than $262. Furthermore, the combination of routine vaccination and large catch-up campaigns resulted in a greater reduction of dengue burden (by up to 93%) than routine vaccination alone, making it a cost-effective intervention as long as the cost per course of vaccination is $255 or less. Our results show that dengue vaccination would be cost-effective in Brazil even with a relatively low vaccine efficacy in seronegative individuals. PMID:28500811

  16. Cost-effectiveness of treatment of diabetic macular edema.

    PubMed

    Pershing, Suzann; Enns, Eva A; Matesic, Brian; Owens, Douglas K; Goldhaber-Fiebert, Jeremy D

    2014-01-07

    Macular edema is the most common cause of vision loss among patients with diabetes. To determine the cost-effectiveness of different treatments of diabetic macular edema (DME). Markov model. Published literature and expert opinion. Patients with clinically significant DME. Lifetime. Societal. Laser treatment, intraocular injections of triamcinolone or a vascular endothelial growth factor (VEGF) inhibitor, or a combination of both. Discounted costs, gains in quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). All treatments except laser monotherapy substantially reduced costs, and all treatments except triamcinolone monotherapy increased QALYs. Laser treatment plus a VEGF inhibitor achieved the greatest benefit, gaining 0.56 QALYs at a cost of $6975 for an ICER of $12 410 per QALY compared with laser treatment plus triamcinolone. Monotherapy with a VEGF inhibitor achieved similar outcomes to combination therapy with laser treatment plus a VEGF inhibitor. Laser monotherapy and triamcinolone monotherapy were less effective and more costly than combination therapy. VEGF inhibitor monotherapy was sometimes preferred over laser treatment plus a VEGF inhibitor, depending on the reduction in quality of life with loss of visual acuity. When the VEGF inhibitor bevacizumab was as effective as ranibizumab, it was preferable because of its lower cost. Long-term outcome data for treated and untreated diseases are limited. The most effective treatment of DME is VEGF inhibitor injections with or without laser treatment. This therapy compares favorably with cost-effective interventions for other conditions. Agency for Healthcare Research and Quality.

  17. River Temperature Dynamics and Habitat Characteristics as Predictors of Salmonid Abundance using Fiber-Optic Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Gryczkowski, L.; Gallion, D.; Haeseker, S.; Bower, R.; Collier, M.; Selker, J. S.; Scherberg, J.; Henry, R.

    2011-12-01

    Salmonids require cool water for all life stages, including spawning and growth. Excessive water temperature causes reduced growth and increased disease and mortality. During the summer, salmonids seek local zones of cooler water as a refuge from elevated temperatures. They also prefer specific habitat features such as boulders and overhanging vegetation. The purpose of this study is to determine whether temperature dynamics or commonly measured fish habitat metrics best explain salmonid abundance. The study site was a 2-kilometer reach of the Walla Walla River near Milton-Freewater, OR, USA, which provides habitat for the salmonids chinook salmon (Oncorhynchus tshawytscha), steelhead/rainbow trout (Oncorhynchus mykiss), mountain whitefish (Prosopium williamsoni), and the endangered bull trout (Salvelinus confluentus). The Walla Walla River is listed as an impaired water body under section 303(d) of the Clean Water Act due to temperature. The associated total maximum daily load (TMDL) calls for temperatures to be below 18 °C at all times for salmonid rearing and migration; however, river temperatures surpassed 24 °C in parts of the study reach in 2009. The two largest factors contributing to the warmer water are reduced riparian vegetation, which decreases shading and increases direct solar radiation, and decreased summer flows caused by diversions and irrigation for agriculture. Fiber-optic distributed temperature sensing has emerged as a unique and powerful tool for ecological applications because of its high spatial and temporal resolution. In this study, meter-scale temperature measurements were obtained at 15-minute intervals along the length of the study reach, allowing for the detection and quantification of cold water inflows during the summer of 2009. The cold water inflows were classified as groundwater or hyporheic sources based on the diurnal temperature patterns. Snorkel surveys were conducted in mid-July and mid-August, 2009 to enumerate salmonid

  18. The evolution of cooperation by the Hankshaw effect.

    PubMed

    Hammarlund, Sarah P; Connelly, Brian D; Dickinson, Katherine J; Kerr, Benjamin

    2016-06-01

    The evolution of cooperation-costly behavior that benefits others-faces one clear obstacle. Namely, cooperators are always at a competitive disadvantage relative to defectors, individuals that reap the benefits, but evade the cost of cooperation. One solution to this problem involves genetic hitchhiking, where the allele encoding cooperation becomes linked to a beneficial mutation, allowing cooperation to rise in abundance. Here, we explore hitchhiking in the context of adaptation to a stressful environment by cooperators and defectors with spatially limited dispersal. Under such conditions, clustered cooperators reach higher local densities, thereby experiencing more mutational opportunities than defectors. Thus, the allele encoding cooperation has a greater probability of hitchhiking with alleles conferring stress adaptation. We label this probabilistic enhancement the "Hankshaw effect" after the character Sissy Hankshaw, whose anomalously large thumbs made her a singularly effective hitchhiker. Using an agent-based model, we reveal a broad set of conditions that allow the evolution of cooperation through this effect. Additionally, we show that spite, a costly behavior that harms others, can evolve by the Hankshaw effect. While in an unchanging environment these costly social behaviors have transient success, in a dynamic environment, cooperation and spite can persist indefinitely. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  19. Cost effectiveness and efficiency in assistive technology service delivery.

    PubMed

    Warren, C G

    1993-01-01

    In order to develop and maintain a viable service delivery program, the realities of cost effectiveness and cost efficiency in providing assistive technology must be addressed. Cost effectiveness relates to value of the outcome compared to the expenditures. Cost efficiency analyzes how a provider uses available resources to supply goods and services. This paper describes how basic business principles of benefit/cost analysis can be used to determine cost effectiveness. In addition, basic accounting principles are used to illustrate methods of evaluating a program's cost efficiency. Service providers are encouraged to measure their own program's effectiveness and efficiency (and potential viability) in light of current trends. This paper is meant to serve as a catalyst for continued dialogue on this topic.

  20. Modelling and Optimal Control of Typhoid Fever Disease with Cost-Effective Strategies.

    PubMed

    Tilahun, Getachew Teshome; Makinde, Oluwole Daniel; Malonza, David

    2017-01-01

    We propose and analyze a compartmental nonlinear deterministic mathematical model for the typhoid fever outbreak and optimal control strategies in a community with varying population. The model is studied qualitatively using stability theory of differential equations and the basic reproductive number that represents the epidemic indicator is obtained from the largest eigenvalue of the next-generation matrix. Both local and global asymptotic stability conditions for disease-free and endemic equilibria are determined. The model exhibits a forward transcritical bifurcation and the sensitivity analysis is performed. The optimal control problem is designed by applying Pontryagin maximum principle with three control strategies, namely, the prevention strategy through sanitation, proper hygiene, and vaccination; the treatment strategy through application of appropriate medicine; and the screening of the carriers. The cost functional accounts for the cost involved in prevention, screening, and treatment together with the total number of the infected persons averted. Numerical results for the typhoid outbreak dynamics and its optimal control revealed that a combination of prevention and treatment is the best cost-effective strategy to eradicate the disease.

  1. Effects of drainage-basin geomorphology on insectivorous bird abundance in temperate forests.

    PubMed

    Iwata, Tomoya; Urabe, Jotaro; Mitsuhashi, Hiromune

    2010-10-01

    Interfaces between terrestrial and stream ecosystems often enhance species diversity and population abundance of ecological communities beyond levels that would be expected separately from both the ecosystems. Nevertheless, no study has examined how stream configuration within a watershed influences the population of terrestrial predators at the drainage-basin scale. We examined the habitat and abundance relationships of forest insectivorous birds in eight drainage basins in a cool temperate forest of Japan during spring and summer. Each basin has different drainage-basin geomorphology, such as the density and frequency of stream channels. In spring, when terrestrial arthropod prey biomass is limited, insectivorous birds aggregated in habitats closer to streams, where emerging aquatic prey was abundant. Nevertheless, birds ceased to aggregate around streams in summer because terrestrial prey became plentiful. Watershed-scale analyses showed that drainage basins with longer stream channels per unit area sustained higher densities of insectivorous birds. Moreover, such effects of streams on birds continued from spring through summer, even though birds dispersed out of riparian areas in the summer. Although our data are from only a single year, our findings imply that physical modifications of stream channels may reduce populations of forest birds; thus, they emphasize the importance of landscape-based management approaches that consider both stream and forest ecosystems for watershed biodiversity conservation. © 2010 Society for Conservation Biology.

  2. Clonal growth and plant species abundance.

    PubMed

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-08-01

    Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf-height-seed) traits and by actual performance in the botanical garden. Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area - height - seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially underlying clonal growth effects on abundance. Garden

  3. Cost-effectiveness of microscopy of urethral smears for asymptomatic Mycoplasma genitalium urethritis in men in England.

    PubMed

    Sutton, Andrew J; Roberts, Tracy E; Jackson, Louise; Saunders, John; White, Peter J; Birger, Ruthie; Estcourt, Claudia

    2018-01-01

    The objective was to determine whether or not the limited use of urethral microscopy to diagnose asymptomatic and symptomatic non-chlamydial, non-gonococcal urethritis (NCNGU) in men is a cost-effective strategy to avert pelvic inflammatory disease (PID), ectopic pregnancy or infertility in female partners. Outputs from a transmission dynamic model of NCNGU in a population of 16-30 year olds in England simulating the number of consultations, PID cases and patients treated over time amongst others, were used along with secondary data to undertake a cost-effectiveness analysis carried out from a health care provider perspective. The main outcome measure was cost per case of PID averted. A secondary outcome measure was cost per major outcome averted, where a major outcome is a case of symptomatic PID, ectopic pregnancy, or infertility. Offering a limited number of asymptomatic men urethral microscopy was more effective than the current practice of no microscopy in terms of reducing the number of cases of PID with an incremental cost-effectiveness ratio of £15,700, meaning that an investment of £15,800 is required to avert one case of PID. For major outcomes averted, offering some asymptomatic men urethral microscopy was again found to be more effective than no microscopy, but here an investment of £49,900 is required to avert one major outcome. Testing asymptomatic men for NCNGU in a small number of genitourinary medicine settings in England is not cost-effective, and thus by maintaining the current practice of not offering this patient group microscopy, this continues to make savings for the health care provider.

  4. Cost-Effectiveness of Nitrogen Mitigation by Alternative ...

    EPA Pesticide Factsheets

    Household wastewater, especially from conventional septic systems, is a major contributor to nitrogen pollution. Alternative household wastewater management technologies provide similar sewerage management services but their life cycle costs and nitrogen flow implications remain uncertain. We seek to address two key questions: (1) what are the total costs, nitrogen mitigation potential, and cost-effectiveness of a range of conventional and alternative municipal wastewater treatment technologies, and (2) what uncertainties influence these outcomes, and how can we improve our understanding of these technologies? We estimate a household nitrogen mass balance for various household wastewater treatment systems and combine this mass balance with life cycle cost assessment to calculate the cost-effectiveness of nitrogen mitigation, which we define as nitrogen removed from the local watershed. We apply our methods to Falmouth, MA, where failing septic systems have caused heightened eutrophication in local receiving water bodies. We find that flushing and dry (composting) urine-diversion toilets paired with conventional septic systems for greywater management demonstrate the lowest life cycle cost and highest cost-effectiveness (dollars per kilogram of nitrogen removed from the watershed). Composting toilets and neighborhood-scale blackwater digesters are also attractive options in some cases, particularly best-case nitrogen mitigation; innovative/advanced septic system

  5. Cost-effectiveness of emergency contraception options over 1 year.

    PubMed

    Bellows, Brandon K; Tak, Casey R; Sanders, Jessica N; Turok, David K; Schwarz, Eleanor B

    2018-05-01

    The copper intrauterine device is the most effective form of emergency contraception and can also provide long-term contraception. The levonorgestrel intrauterine device has also been studied in combination with oral levonorgestrel for women seeking emergency contraception. However, intrauterine devices have higher up-front costs than oral methods, such as ulipristal acetate and levonorgestrel. Health care payers and decision makers (eg, health care insurers, government programs) with financial constraints must determine if the increased effectiveness of intrauterine device emergency contraception methods are worth the additional costs. We sought to compare the cost-effectiveness of 4 emergency contraception strategies-ulipristal acetate, oral levonorgestrel, copper intrauterine device, and oral levonorgestrel plus same-day levonorgestrel intrauterine device-over 1 year from a US payer perspective. Costs (2017 US dollars) and pregnancies were estimated over 1 year using a Markov model of 1000 women seeking emergency contraception. Every 28-day cycle, the model estimated the predicted number of pregnancy outcomes (ie, live birth, ectopic pregnancy, spontaneous abortion, or induced abortion) resulting from emergency contraception failure and subsequent contraception use. Model inputs were derived from published literature and national sources. An emergency contraception strategy was considered cost-effective if the incremental cost-effectiveness ratio (ie, the cost to prevent 1 additional pregnancy) was less than the weighted average cost of pregnancy outcomes in the United States ($5167). The incremental cost-effectiveness ratios and probability of being the most cost-effective emergency contraception strategy were calculated from 1000 probabilistic model iterations. One-way sensitivity analyses were used to examine uncertainty in the cost of emergency contraception, subsequent contraception, and pregnancy outcomes as well as the model probabilities. In 1000 women

  6. The activated sludge ecosystem contains a core community of abundant organisms

    PubMed Central

    Saunders, Aaron M; Albertsen, Mads; Vollertsen, Jes; Nielsen, Per H

    2016-01-01

    Understanding the microbial ecology of a system requires that the observed population dynamics can be linked to their metabolic functions. However, functional characterization is laborious and the choice of organisms should be prioritized to those that are frequently abundant (core) or transiently abundant, which are therefore putatively make the greatest contribution to carbon turnover in the system. We analyzed the microbial communities in 13 Danish wastewater treatment plants with nutrient removal in consecutive years and a single plant periodically over 6 years, using Illumina sequencing of 16S ribosomal RNA amplicons of the V4 region. The plants contained a core community of 63 abundant genus-level operational taxonomic units (OTUs) that made up 68% of the total reads. A core community consisting of abundant OTUs was also observed within the incoming wastewater to three plants. The net growth rate for individual OTUs was quantified using mass balance, and it was found that 10% of the total reads in the activated sludge were from slow or non-growing OTUs, and that their measured abundance was primarily because of immigration with the wastewater. Transiently abundant organisms were also identified. Among them the genus Nitrotoga (class Betaproteobacteria) was the most abundant putative nitrite oxidizer in a number of activated sludge plants, which challenges previous assumptions that Nitrospira (phylum Nitrospirae) are the primary nitrite-oxidizers in activated sludge systems with nutrient removal. PMID:26262816

  7. Boron Abundances in A and B-type Stars

    NASA Technical Reports Server (NTRS)

    Lambert, David L.

    1997-01-01

    Boron abundances in A- and B-type stars may be a successful way to track evolutionary effects in these hot stars. The light elements - Li, Be, and B - are tracers of exposure to temperatures more moderate than those in which the H-burning CN-cycle operates. Thus, any exposure of surface stellar layers to deeper layers will affect these light element abundances. Li and Be are used in this role in investigations of evolutionary processes in cool stars, but are not observable in hotter stars. An investigation of boron, however, is possible through the B II 1362 A resonance line. We have gathered high resolution spectra from the IUE database of A- and B-type stars near 10 solar mass for which nitrogen abundances have been determined. The B II 1362 A line is blended throughout; the temperature range of this program, requiring spectrum syntheses to recover the boron abundances. For no star could we synthesize the 1362 A region using the meteoritic/solar boron abundance of log e (B) = 2.88; a lower boron abundance was necessary which may reflect evolutionary effects (e.g., mass loss or mixing near the main-sequence), the natal composition of the star forming regions, or a systematic error in the analyses (e.g., non-LTE effects). Regardless of the initial boron abundance, and despite the possibility of non-LTE effects, it seems clear that boron is severely depleted in some stars. It may be that the nitrogen and boron abundances are anticorrelated, as would be expected from mixing between the H-burning and outer stellar layers. If, as we suspect, a residue of boron is present in the A-type supergiants, we may exclude a scenario in which mixing occurs continuously between the surface and the deep layers operating the CN-cycle. Further exploitation of the B II 1362 A line as an indicator of the evolutionary status of A- and B-type stars will require a larger stellar sample to be observed with higher signal-to-noise as attainable with the Hubble Space Telescope.

  8. Meta-analysis reveals that seed-applied neonicotinoids and pyrethroids have similar negative effects on abundance of arthropod natural enemies

    PubMed Central

    Tooker, John F.

    2016-01-01

    Background Seed-applied neonicotinoids are widely used in agriculture, yet their effects on non-target species remain incompletely understood. One important group of non-target species is arthropod natural enemies (predators and parasitoids), which contribute considerably to suppression of crop pests. We hypothesized that seed-applied neonicotinoids reduce natural-enemy abundance, but not as strongly as alternative insecticide options such as soil- and foliar-applied pyrethroids. Furthermore we hypothesized that seed-applied neonicotinoids affect natural enemies through a combination of toxin exposure and prey scarcity. Methods To test our hypotheses, we compiled datasets comprising observations from randomized field studies in North America and Europe that compared natural-enemy abundance in plots that were planted with seed-applied neonicotinoids to control plots that were either (1) managed without insecticides (20 studies, 56 site-years, 607 observations) or (2) managed with pyrethroid insecticides (eight studies, 15 site-years, 384 observations). Using the effect size Hedge’s d as the response variable, we used meta-regression to estimate the overall effect of seed-applied neonicotinoids on natural-enemy abundance and to test the influence of potential moderating factors. Results Seed-applied neonicotinoids reduced the abundance of arthropod natural enemies compared to untreated controls (d = −0.30 ± 0.10 [95% confidence interval]), and as predicted under toxin exposure this effect was stronger for insect than for non-insect taxa (QM = 8.70, df = 1, P = 0.003). Moreover, seed-applied neonicotinoids affected the abundance of arthropod natural enemies similarly to soil- or foliar-applied pyrethroids (d = 0.16 ± 0.42 or −0.02 ± 0.12; with or without one outlying study). Effect sizes were surprisingly consistent across both datasets (I2 = 2.7% for no-insecticide controls; I2 = 0% for pyrethroid controls), suggesting little moderating influence of

  9. Meta-analysis reveals that seed-applied neonicotinoids and pyrethroids have similar negative effects on abundance of arthropod natural enemies.

    PubMed

    Douglas, Margaret R; Tooker, John F

    2016-01-01

    Seed-applied neonicotinoids are widely used in agriculture, yet their effects on non-target species remain incompletely understood. One important group of non-target species is arthropod natural enemies (predators and parasitoids), which contribute considerably to suppression of crop pests. We hypothesized that seed-applied neonicotinoids reduce natural-enemy abundance, but not as strongly as alternative insecticide options such as soil- and foliar-applied pyrethroids. Furthermore we hypothesized that seed-applied neonicotinoids affect natural enemies through a combination of toxin exposure and prey scarcity. To test our hypotheses, we compiled datasets comprising observations from randomized field studies in North America and Europe that compared natural-enemy abundance in plots that were planted with seed-applied neonicotinoids to control plots that were either (1) managed without insecticides (20 studies, 56 site-years, 607 observations) or (2) managed with pyrethroid insecticides (eight studies, 15 site-years, 384 observations). Using the effect size Hedge's d as the response variable, we used meta-regression to estimate the overall effect of seed-applied neonicotinoids on natural-enemy abundance and to test the influence of potential moderating factors. Seed-applied neonicotinoids reduced the abundance of arthropod natural enemies compared to untreated controls ( d = -0.30 ± 0.10 [95% confidence interval]), and as predicted under toxin exposure this effect was stronger for insect than for non-insect taxa ( Q M = 8.70, df = 1, P = 0.003). Moreover, seed-applied neonicotinoids affected the abundance of arthropod natural enemies similarly to soil- or foliar-applied pyrethroids ( d = 0.16 ± 0.42 or -0.02 ± 0.12; with or without one outlying study). Effect sizes were surprisingly consistent across both datasets ( I 2  = 2.7% for no-insecticide controls; I 2  = 0% for pyrethroid controls), suggesting little moderating influence of crop species

  10. Recommendations for Conduct, Methodological Practices, and Reporting of Cost-effectiveness Analyses: Second Panel on Cost-Effectiveness in Health and Medicine.

    PubMed

    Sanders, Gillian D; Neumann, Peter J; Basu, Anirban; Brock, Dan W; Feeny, David; Krahn, Murray; Kuntz, Karen M; Meltzer, David O; Owens, Douglas K; Prosser, Lisa A; Salomon, Joshua A; Sculpher, Mark J; Trikalinos, Thomas A; Russell, Louise B; Siegel, Joanna E; Ganiats, Theodore G

    2016-09-13

    Since publication of the report by the Panel on Cost-Effectiveness in Health and Medicine in 1996, researchers have advanced the methods of cost-effectiveness analysis, and policy makers have experimented with its application. The need to deliver health care efficiently and the importance of using analytic techniques to understand the clinical and economic consequences of strategies to improve health have increased in recent years. To review the state of the field and provide recommendations to improve the quality of cost-effectiveness analyses. The intended audiences include researchers, government policy makers, public health officials, health care administrators, payers, businesses, clinicians, patients, and consumers. In 2012, the Second Panel on Cost-Effectiveness in Health and Medicine was formed and included 2 co-chairs, 13 members, and 3 additional members of a leadership group. These members were selected on the basis of their experience in the field to provide broad expertise in the design, conduct, and use of cost-effectiveness analyses. Over the next 3.5 years, the panel developed recommendations by consensus. These recommendations were then reviewed by invited external reviewers and through a public posting process. The concept of a "reference case" and a set of standard methodological practices that all cost-effectiveness analyses should follow to improve quality and comparability are recommended. All cost-effectiveness analyses should report 2 reference case analyses: one based on a health care sector perspective and another based on a societal perspective. The use of an "impact inventory," which is a structured table that contains consequences (both inside and outside the formal health care sector), intended to clarify the scope and boundaries of the 2 reference case analyses is also recommended. This special communication reviews these recommendations and others concerning the estimation of the consequences of interventions, the valuation of health

  11. The cost-effectiveness of infliximab in Crohn's disease.

    PubMed

    Smart, Claire; Selinger, Christian P

    2014-10-01

    Crohn's disease (CD) is a chronic inflammatory condition that can affect any part of the gastrointestinal tract. It leads to severe symptoms and reduced quality of life. Infliximab is a monoclonal antibody against TNF-α and is effective in treating moderate to severe CD. It is associated with high treatment costs, but subsequent reductions in hospitalisation and surgery have been reported. This review examines the evidence for the cost-effectiveness of infliximab for the treatment of CD. Studies have been found to be very heterogeneous depending on setting, costs assumed and clinical data. Within the UK setting infliximab has been found to be cost effective with increased costs of around £25,000 per quality adjusted life year gained.

  12. The value of heterogeneity for cost-effectiveness subgroup analysis: conceptual framework and application.

    PubMed

    Espinoza, Manuel A; Manca, Andrea; Claxton, Karl; Sculpher, Mark J

    2014-11-01

    This article develops a general framework to guide the use of subgroup cost-effectiveness analysis for decision making in a collectively funded health system. In doing so, it addresses 2 key policy questions, namely, the identification and selection of subgroups, while distinguishing 2 sources of potential value associated with heterogeneity. These are 1) the value of revealing the factors associated with heterogeneity in costs and outcomes using existing evidence (static value) and 2) the value of acquiring further subgroup-related evidence to resolve the uncertainty given the current understanding of heterogeneity (dynamic value). Consideration of these 2 sources of value can guide subgroup-specific treatment decisions and inform whether further research should be conducted to resolve uncertainty to explain variability in costs and outcomes. We apply the proposed methods to a cost-effectiveness analysis for the management of patients with acute coronary syndrome. This study presents the expected net benefits under current and perfect information when subgroups are defined based on the use and combination of 6 binary covariates. The results of the case study confirm the theoretical expectations. As more subgroups are considered, the marginal net benefit gains obtained under the current information show diminishing marginal returns, and the expected value of perfect information shows a decreasing trend. We present a suggested algorithm that synthesizes the results to guide policy. © The Author(s) 2014.

  13. Cost-effectiveness of dryland forest restoration evaluated by spatial analysis of ecosystem services

    PubMed Central

    Birch, Jennifer C.; Newton, Adrian C.; Aquino, Claudia Alvarez; Cantarello, Elena; Echeverría, Cristian; Kitzberger, Thomas; Schiappacasse, Ignacio; Garavito, Natalia Tejedor

    2010-01-01

    Although ecological restoration is widely used to combat environmental degradation, very few studies have evaluated the cost-effectiveness of this approach. We examine the potential impact of forest restoration on the value of multiple ecosystem services across four dryland areas in Latin America, by estimating the net value of ecosystem service benefits under different reforestation scenarios. The values of selected ecosystem services were mapped under each scenario, supported by the use of a spatially explicit model of forest dynamics. We explored the economic potential of a change in land use from livestock grazing to restored native forest using different discount rates and performed a cost–benefit analysis of three restoration scenarios. Results show that passive restoration is cost-effective for all study areas on the basis of the services analyzed, whereas the benefits from active restoration are generally outweighed by the relatively high costs involved. These findings were found to be relatively insensitive to discount rate but were sensitive to the market value of carbon. Substantial variation in values was recorded between study areas, demonstrating that ecosystem service values are strongly context specific. However, spatial analysis enabled localized areas of net benefits to be identified, indicating the value of this approach for identifying the relative costs and benefits of restoration interventions across a landscape. PMID:21106761

  14. 10 CFR 436.13 - Presuming cost-effectiveness results.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Presuming cost-effectiveness results. 436.13 Section 436.13 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.13 Presuming cost-effectiveness results. (a) If...

  15. 10 CFR 436.13 - Presuming cost-effectiveness results.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Presuming cost-effectiveness results. 436.13 Section 436.13 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.13 Presuming cost-effectiveness results. (a) If...

  16. 10 CFR 436.13 - Presuming cost-effectiveness results.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Presuming cost-effectiveness results. 436.13 Section 436.13 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.13 Presuming cost-effectiveness results. (a) If...

  17. 10 CFR 436.13 - Presuming cost-effectiveness results.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Presuming cost-effectiveness results. 436.13 Section 436.13 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methodology and Procedures for Life Cycle Cost Analyses § 436.13 Presuming cost-effectiveness results. (a) If...

  18. Is Taurolidine-citrate an effective and cost-effective hemodialysis catheter lock solution? A systematic review and cost- effectiveness analysis.

    PubMed

    Kavosi, Zahra; Sarikhani Khorrami, Maryam; Keshavarz, Khosro; Jafari, Abdosaleh; Hashemi Meshkini, Amir; Safaei, Hamid Reza; Nikfar, Shekoufeh

    2016-01-01

    Prevention of catheter-related infection is of prime importance,. However, because of the risks caused by the leakage of circulating antibiotics and development of resistance to antibiotics, they are replaced by lock solutions. The aim of this study was to evaluate the efficacy and cost- effectiveness of taurolidine-citrate as a hemodialysis catheter lock solution compared to other common alternatives in Iran. To evaluate the efficacy of taurolidine-citrate, a systematic review was conducted by searching electronic databases. The outcomes of interest for cost-effectiveness analysis were as follows: "Catheter-related bacteremia episodes"; "catheter-related bacteremia-free survival"; "catheter thrombosis rate" for efficacy evaluation and "reduction of catheter-related infection". For evidence synthesis, a meta-analysis was conducted on the extracted efficacy data. To evaluate the cost of treatments, direct medical costs were included, and the incremental cost-effectiveness ratio was calculated for each comparison. The payers' (patients and insurance companies) perspectives were used for cost analysis. After carrying out the systematic process, three articles were included in the analysis. Considering 95% confidence interval, the relative difference was -0.16 (-0.25 to -0.07) for catheterrelated bacteremia episode, indicating that the rate of catheter-related infections in hemodialysis patients who used taurolidine-citrate was 16% less than in those hemodialysis patients who received heparin. Considering 95% confidence interval, the relative difference was 0.13 (-0.06 0.32) for catheter thrombosis, showing that the rate of catheter-related thrombosis in hemodialysis patients who used taurolidine-citrate was 13% more than in hemodialysis patients who received heparin. The results of this analysis indicated that taurolidine-citrate, compared to heparin, was more effective in preventing catheter-related infection; therefore, it could be considered as a superior strategy

  19. The effects of urban warming on herbivore abundance and street tree condition.

    PubMed

    Dale, Adam G; Frank, Steven D

    2014-01-01

    Trees are essential to urban habitats because they provide services that benefit the environment and improve human health. Unfortunately, urban trees often have more herbivorous insect pests than rural trees but the mechanisms and consequences of these infestations are not well documented. Here, we examine how temperature affects the abundance of a scale insect, Melanaspis tenebricosa (Comstock) (Hemiptera: Diaspididae), on one of the most commonly planted street trees in the eastern U.S. Next, we examine how both pest abundance and temperature are associated with water stress, growth, and condition of 26 urban street trees. Although trees in the warmest urban sites grew the most, they were more water stressed and in worse condition than trees in cooler sites. Our analyses indicate that visible declines in tree condition were best explained by scale-insect infestation rather than temperature. To test the broader relevance of these results, we extend our analysis to a database of more than 2700 Raleigh, US street trees. Plotting these trees on a Landsat thermal image of Raleigh, we found that warmer sites had over 70% more trees in poor condition than those in cooler sites. Our results support previous studies linking warmer urban habitats to greater pest abundance and extend this association to show its effect on street tree condition. Our results suggest that street tree condition and ecosystem services may decline as urban expansion and global warming exacerbate the urban heat island effect. Although our non-probability sampling method limits our scope of inference, our results present a gloomy outlook for urban forests and emphasize the need for management tools. Existing urban tree inventories and thermal maps could be used to identify species that would be most suitable for urban conditions.

  20. Investigation of dynamic ground effect

    NASA Technical Reports Server (NTRS)

    Chang, Ray Chung; Muirhead, Vincent U.

    1987-01-01

    An experimental investigation of dynamic ground effect was conducted in the Univ. of Kansas wind tunnel using delta wings of 60, 70, 75 deg sweep; the XB-70 wing; and the F-104A wing. Both static and dynamic tests were made. Test data were compared to other test data, including dynamic flight test data of the XB-70 and F-104A. Limited flow visualization test were conducted. A significant dynamic effect was found for highly swept delta wings.

  1. Consumer-Operated Service Programs: monetary and donated costs and cost-effectiveness.

    PubMed

    Yates, Brian T; Mannix, Danyelle; Freed, Michael C; Campbell, Jean; Johnsen, Matthew; Jones, Kristine; Blyler, Crystal R

    2011-01-01

    Examine cost differences between Consumer Operated Service Programs (COSPs) as possibly determined by a) size of program, b) use of volunteers and other donated resources, c) cost-of-living differences between program locales, d) COSP model applied, and e) delivery system used to implement the COSP model. As part of a larger evaluation of COSP, data on operating costs, enrollments, and mobilization of donated resources were collected for eight programs representing three COSP models (drop-in centers, mutual support, and education/advocacy training). Because the 8 programs were operated in geographically diverse areas of the US, costs were examined with and without adjustment for differences in local cost of living. Because some COSPs use volunteers and other donated resources, costs were measured with and without these resources being monetized. Scale of operation also was considered as a mediating variable for differences in program costs. Cost per visit, cost per consumer per quarter, and total program cost were calculated separately for funds spent and for resources donated for each COSP. Differences between COSPs in cost per consumer and cost per visit seem better explained by economies of scale and delivery system used than by cost-of-living differences between program locations or COSP model. Given others' findings that different COSP models produce little variation in service effectiveness, minimize service costs by maximizing scale of operation while using a delivery system that allows staff and facilities resources to be increased or decreased quickly to match number of consumers seeking services.

  2. Cost and cost-effectiveness of community-based care for tuberculosis in Cape Town, South Africa.

    PubMed

    Sinanovic, E; Floyd, K; Dudley, L; Azevedo, V; Grant, R; Maher, D

    2003-09-01

    Guguletu and Nyanga areas of Cape Town, South Africa. To evaluate the affordability and cost-effectiveness of community involvement in tuberculosis (TB) care. A cost-effectiveness analysis comparing treatment for new smear-positive pulmonary and retreatment TB patients in two similar townships, one providing clinic-based-care with community-based observation options available for its TB patients (Guguletu) and one providing clinic-based care only, with no community-based observation of treatment (Nyanga). Costs were assessed from a societal perspective in 1997 US dollars, and cost-effectiveness was calculated as the cost per patient successfully treated. TB treatment in Guguletu was more cost-effective than TB treatment in Nyanga for both new and retreatment patients (dollars 726 vs. dollars 1201 and dollars 1419 vs. dollars 2058, respectively). This reflected both lower costs (dollars 495 vs. dollars 769 per patient treated for new cases; dollars 823 vs. dollars 1070 per patient treated for retreatment cases) and better treatment outcomes (successful treatment rate 68% vs. 64% and 58% vs. 52% for new and retreatment patients, respectively). Within Guguletu, community-based care was more than twice as cost-effective as clinic-based care (dollars 392 vs. dollars 1302 per patient successfully treated for new patients, and dollars 766 vs. dollars 2008 for retreatment patients), for similar reasons (e.g., for new cases, dollars 314 vs. dollars 703 per patient treated, successful treatment rate 80% vs. 54%). Community involvement in TB care can improve the affordability and cost-effectiveness of TB treatment in urban South Africa. Expansion in the Western Cape and in similar areas of the country is worthy of serious consideration by planners and policy-makers.

  3. A review of the costs and cost effectiveness of interventions in chronic kidney disease: implications for policy.

    PubMed

    Menzin, Joseph; Lines, Lisa M; Weiner, Daniel E; Neumann, Peter J; Nichols, Christine; Rodriguez, Lauren; Agodoa, Irene; Mayne, Tracy

    2011-10-01

    Given rising healthcare costs and a growing population of patients with chronic kidney disease (CKD), there is an urgent need to identify health interventions that provide good value for money. For this review, the English-language literature was searched for studies of interventions in CKD reporting an original incremental cost-utility (cost per QALY) or cost-effectiveness (cost per life-year) ratio. Published cost studies that did not report cost-effectiveness or cost-utility ratios were also reviewed. League tables were then created for both cost-utility and cost-effectiveness ratios to assess interventions in patients with stage 1-4 CKD, waitlist and transplant patients and those with end-stage renal disease (ESRD). In addition, the percentage of cost-saving or dominant interventions (those that save money and improve health) was compared across these three disease categories. A total of 84 studies were included, contributing 72 cost-utility ratios, 20 cost-effectiveness ratios and 42 other cost measures. Many of the interventions were dominant over the comparator, indicating better health outcomes and lower costs. For the three disease categories, the greatest number of dominant or cost-saving interventions was reported for stage 1-4 CKD patients, followed by waitlist and transplant recipients and those with ESRD (91%, 87% and 55% of studies reporting a dominant or cost-saving intervention, respectively). There is evidence of opportunities to lower costs in the treatment of patients with CKD, while either improving or maintaining the quality of care. In order to realize these cost savings, efforts will be required to promote and effectively implement changes in treatment practices.

  4. [Cost- effectiveness analysis of pneumococcal vaccination in Iceland].

    PubMed

    Björnsdóttir, Margrét

    2010-09-01

    Pneumococcus is a common cause of disease among children and the elderly. With the emergence of resistant serotypes, antibiotic treatment is getting limited. Many countries have therefore introduced a vaccination program among children against the most common serotypes. The aim of this study was to analyse cost-effectiveness of adding a vaccination program against pneumococcus in Iceland. A cost-effectiveness analysis was carried out from a societal perspective where the cost-effectiveness ratio ICER was estimated from the cost of each additional life and life year saved. The analyse was based on the year 2008 and all cost were calculated accordingly. The rate of 3% was used for net present-value calculation. Annual societal cost due to pneumococcus in Iceland was estimated to be 718.146.252 ISK if children would be vaccinated but 565.026.552 ISK if they would not be vaccinated. The additional cost due to the vaccination program was therefore 153.119.700 ISK . The vaccination program could save 0,669 lives among children aged 0-4 years old and 21.11 life years. The cost was 228.878.476 ISK for each additional life saved and 7.253.420 ISK for each additional life year saved. Given initial assumptions the results indicate that a vaccination programme against pneumococcal disease in Iceland would be cost effective.

  5. A cost-effectiveness evaluation of hospital discharge counseling by pharmacists.

    PubMed

    Chinthammit, Chanadda; Armstrong, Edward P; Warholak, Terri L

    2012-04-01

    This study estimated the cost-effectiveness of pharmacist discharge counseling on medication-related morbidity in both the high-risk elderly and general US population. A cost-effectiveness decision analytic model was developed using a health care system perspective based on published clinical trials. Costs included direct medical costs, and the effectiveness unit was patients discharged without suffering a subsequent adverse drug event. A systematic review of published studies was conducted to estimate variable probabilities in the cost-effectiveness model. To test the robustness of the results, a second-order probabilistic sensitivity analysis (Monte Carlo simulation) was used to run 10 000 cases through the model sampling across all distributions simultaneously. Pharmacist counseling at hospital discharge provided a small, but statistically significant, clinical improvement at a similar overall cost. Pharmacist counseling was cost saving in approximately 48% of scenarios and in the remaining scenarios had a low willingness-to-pay threshold for all scenarios being cost-effective. In addition, discharge counseling was more cost-effective in the high-risk elderly population compared to the general population. This cost-effectiveness analysis suggests that discharge counseling by pharmacists is quite cost-effective and estimated to be cost saving in over 48% of cases. High-risk elderly patients appear to especially benefit from these pharmacist services.

  6. Effects of copper on the abundance and diversity of ammonia oxidizers during dairy cattle manure composting.

    PubMed

    Yin, Yanan; Song, Wen; Gu, Jie; Zhang, Kaiyu; Qian, Xun; Zhang, Xin; Zhang, Yajun; Li, Yang; Wang, Xiaojuan

    2016-12-01

    This study investigated the effects of adding Cu(II) at two exposure levels (50 and 500mgkg -1 , i.e., Cu50 and Cu500 treatments, respectively) on the activity of ammonia-oxidizing microorganisms during dairy cattle manure composting. The results showed that the pH, NH 4 + -N, NO 3 - -N, and potential ammonia oxidation values were inhibited significantly by the addition of Cu(II). Furthermore, the abundances of the ammonia-oxidizing archaea (AOA) amoA gene and ammonia-oxidizing bacteria (AOB) amoA gene were determined by quantitative PCR, and their compositions were evaluated by denaturing gradient gel electrophoresis (DGGE). AOA was the dominant ammonia oxidizing microorganism, of which the abundance was much higher than AOB during composting. Cu50 and Cu500 had significant inhibitory effects on the abundance of the amoA gene. The DGGE profile and statistical analysis showed that Cu(II) changed the AOA and AOB community structure and diversity, where Nitrosomonas and Crenarchaeota dominated throughout the composting process. Copyright © 2016. Published by Elsevier Ltd.

  7. Ethical objections against including life-extension costs in cost-effectiveness analysis: a consistent approach.

    PubMed

    Gandjour, Afschin; Müller, Dirk

    2014-10-01

    One of the major ethical concerns regarding cost-effectiveness analysis in health care has been the inclusion of life-extension costs ("it is cheaper to let people die"). For this reason, many analysts have opted to rule out life-extension costs from the analysis. However, surprisingly little has been written in the health economics literature regarding this ethical concern and the resulting practice. The purpose of this work was to present a framework and potential solution for ethical objections against life-extension costs. This work found three levels of ethical concern: (i) with respect to all life-extension costs (disease-related and -unrelated); (ii) with respect to disease-unrelated costs only; and (iii) regarding disease-unrelated costs plus disease-related costs not influenced by the intervention. Excluding all life-extension costs for ethical reasons would require-for reasons of consistency-a simultaneous exclusion of savings from reducing morbidity. At the other extreme, excluding only disease-unrelated life-extension costs for ethical reasons would require-again for reasons of consistency-the exclusion of health gains due to treatment of unrelated diseases. Therefore, addressing ethical concerns regarding the inclusion of life-extension costs necessitates fundamental changes in the calculation of cost effectiveness.

  8. Cost-effectiveness of HPV vaccination in Belize.

    PubMed

    Walwyn, Leslie; Janusz, Cara Bess; Clark, Andrew David; Prieto, Elise; Waight, Eufemia; Largaespada, Natalia

    2015-05-07

    Among women in Belize, cervical cancer is both the leading cancer and the leading cause of cancer deaths. Both the quadrivalent and bivalent human papillomavirus (HPV) vaccines are licensed in Belize. The Ministry of Health of Belize convened a multidisciplinary team to estimate the costs, health benefits, and cost-effectiveness of adding an HPV vaccine to the national immunization schedule. The CERVIVAC cost-effectiveness model (Version 1.123) was used to assess the lifetime health and economic outcomes of vaccinating one cohort of girls aged 10 years against HPV. The comparator was no HPV vaccination. The PAHO Revolving Fund negotiated price of US$ 13.79 per dose was used (for the quadrivalent vaccine) and national data sources were used to define demography, cervical cancer incidence and mortality, cervical cancer treatment costs, and vaccine delivery costs. Estimates from international agencies were used in scenario analysis. In a cohort of ∼4000 Belizean girls tracked over a lifetime, HPV vaccination is estimated to prevent 69 new cases of cervical cancer (undiscounted), and 51 cervical cancer deaths (undiscounted). Considering the potential cervical cancer treatment costs and lost wages avoided by households (societal perspective), the cost per disability-adjusted life year (DALY) averted was estimated to be US$ 429. This increased to US$ 1320 when cervical cancer treatment costs and lost wages were excluded from the analysis. Both estimates are far below the gross domestic product (GDP) per capita of Belize (US$ 4795). The lifetime health care costs saved by the women and their families represent more than 60% of the investment cost needed by the Government for the vaccine. Routine HPV vaccination would be highly cost-effective in Belize. If affordable, efforts should be made to expedite the introduction of this vaccine into the Belizean national immunization program. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Long-term landscape change and bird abundance in Amazonian rainforest fragments.

    PubMed

    Stouffer, Philip C; Bierregaard, Richard O; Strong, Cheryl; Lovejoy, Thomas E

    2006-08-01

    The rainforests of the Amazon basin are being cut by humans at a rate >20,000 km2/year leading to smaller and more isolated patches of forest, with remaining fragments often in the range of 1-100 ha. We analyzed samples of understory birds collected over 20 years from a standardized mist-netting program in 1- to 100-ha rainforest fragments in a dynamic Amazonian landscape near Manaus, Brazil. Across bird guilds, the condition of second growth immediately surrounding fragments was often as important as fragment size or local forest cover in explaining variation in abundance. Some fragments surrounded by 100 m of open pasture showed reductions in insectivorous bird abundance of over 95%, even in landscapes dominated by continuous forest and old second growth. These extreme reductions may be typical throughout Amazonia in small (< or =10 ha), isolated fragments of rainforest. Abundance for some guilds returned to preisolation levels in 10- and 100-ha fragments connected to continuous forest by 20-year-old second growth. Our results show that the consequences of Amazonian forest loss cannot be accurately described without explicit consideration of vegetation dynamics in matrix habitat. Any dichotomous classification of the landscape into 'forest" and "nonforest" misses essential information about the matrix.

  10. Cost-effectiveness of a ROPS retrofit education campaign.

    PubMed

    Myers, M L; Cole, H P; Westneat, S C

    2004-05-01

    A community educational campaign implemented in two Kentucky counties was effective in influencing farmers to retrofit their tractors with rollover protective structures (ROPS) to protect tractor operators from injury in the event of an overturn. This article reports on the cost-effectiveness of this program in the two counties when compared to no program in a control county. A decision analysis indicated that it would be effective at averting 0.27 fatal and 1.53 nonfatal injuries over a 20-year period, and when this analysis was extended statewide, 7.0 fatal and 40 nonfatal injuries would be averted in Kentucky. Over the 20-year period, the cost-per-injury averted was calculated to be $172,657 at a 4% annual discount rate. This cost compared favorably with a national cost of $489,373 per injury averted despite the additional program cost in Kentucky. The principle reason for the increased cost-effectiveness of the Kentucky program was the three-fold higher propensity for tractors to overturn in Kentucky. The cost-per-injury averted in one of the two counties was $112,535. This lower cost was attributed principally to incentive awards financed locally for farmers to retrofit their tractors with ROPS.

  11. 10 CFR 436.13 - Presuming cost-effectiveness results.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Methodology and Procedures for Life Cycle Cost Analyses § 436.13 Presuming cost-effectiveness results. (a) If... life cycle cost-effective without further analysis. (b) A Federal agency may presume that an investment in an energy or water conservation measure retrofit to an existing Federal building is not life cycle...

  12. The Cost-Effectiveness Analysis of Teleglaucoma Screening Device

    PubMed Central

    Thomas, Sera

    2015-01-01

    Glaucoma is the leading cause of irreversible vision loss and costs the American economy $2.9 billion. Teleglaucoma remotely detects glaucoma improving access to ophthalmic care in rural areas. It helps manage glaucoma more efficiently to preserve vision and reduce healthcare costs. A cost-effectiveness analysis was conducted using healthcare provider or third-party payer perspective within rural Canada. The study population were patients at-risk of glaucoma which includes those with diabetes and/or hypertension, family history of glaucoma, adults older than 50 years, and concurrent ocular conditions in rural Alberta. Markov modelling was used to model glaucoma health states. Effectiveness was measured in Quality-Adjusted Life Years (QALYs) and costs were used in Canadian dollars. Using TreeAge Pro 2009, incremental cost-effectiveness ratios (ICER) were developed in dollars per QALYs. Deterministic and probabilistic sensitivity analyses were performed to assess the factors affecting cost-effectiveness. Teleglaucoma had a 20% increase in ophthalmologist-referral rate; it reduced patient travel times by 61 hours and physician wait times by 30% in comparison to in-person examination (standard of care). Teleglaucoma costs $872 per patient screened which was 80% less than in-person examination. Teleglaucoma had a greater incremental effectiveness providing an additional 0.12 QALY per patient examination. It was more sensitive (86.5%) and less specific (78.6%) than in-person examination. Teleglaucoma was more cost-effective than in-person examination with an ICER of-$27,460/QALY. This indicated that teleglaucoma will save $27, 460 for each additional QALY gained. Long term benefits showed teleglaucoma prevents 24% cases of glaucoma blindness after 30 years. Teleglaucoma demonstrated improved health outcomes, as well as, cost benefits. It increases access to ophthalmic care and improves healthcare service efficiency, specifically in rural areas. Teleglaucoma is more cost-effective

  13. Percutaneous Trigger Finger Release: A Cost-effectiveness Analysis.

    PubMed

    Gancarczyk, Stephanie M; Jang, Eugene S; Swart, Eric P; Makhni, Eric C; Kadiyala, Rajendra Kumar

    2016-07-01

    Percutaneous trigger finger releases (TFRs) performed in the office setting are becoming more prevalent. This study compares the costs of in-hospital open TFRs, open TFRs performed in ambulatory surgical centers (ASCs), and in-office percutaneous releases. An expected-value decision-analysis model was constructed from the payer perspective to estimate total costs of the three competing treatment strategies for TFR. Model parameters were estimated based on the best available literature and were tested using multiway sensitivity analysis. Percutaneous TFR performed in the office and then, if needed, revised open TFR performed in the ASC, was the most cost-effective strategy, with an attributed cost of $603. The cost associated with an initial open TFR performed in the ASC was approximately 7% higher. Initial open TFR performed in the hospital was the least cost-effective, with an attributed cost nearly twice that of primary percutaneous TFR. An initial attempt at percutaneous TFR is more cost-effective than an open TFR. Currently, only about 5% of TFRs are performed in the office; therefore, a substantial opportunity exists for cost savings in the future. Decision model level II.

  14. Applications of cost-effectiveness methodologies in behavioral medicine.

    PubMed

    Kaplan, Robert M; Groessl, Erik J

    2002-06-01

    In 1996, the Panel on Cost-Effectiveness in Health and Medicine developed standards for cost-effectiveness analysis. The standards include the use of a societal perspective, that treatments be evaluated in comparison with the best available alternative (rather than with no care at all), and that health benefits be expressed in standardized units. Guidelines for cost accounting were also offered. Among 24,562 references on cost-effectiveness in Medline between 1995 and 2000, only a handful were relevant to behavioral medicine. Only 19 studies published between 1983 and 2000 met criteria for further evaluation. Among analyses that were reported, only 2 studies were found consistent with the Panel's criteria for high-quality analyses, although more recent studies were more likely to meet methodological standards. There are substantial opportunities to advance behavioral medicine by performing standardized cost-effectiveness analyses.

  15. Effects of transgenic cry1Ie maize on non-lepidopteran pest abundance, diversity and community composition.

    PubMed

    Guo, Jingfei; He, Kanglai; Bai, Shuxiong; Zhang, Tiantao; Liu, Yunjun; Wang, Fuxin; Wang, Zhenying

    2016-12-01

    Non-lepidopteran pests are exposed to, and may be influenced by, Bt toxins when feeding on Bt maize that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt). In order to assess the potential effects of transgenic cry1Ie maize on non-lepidopteran pest species and ecological communities, a 2-year field study was conducted to compare the non-lepidopteran pest abundance, diversity and community composition between transgenic cry1Ie maize (Event IE09S034, Bt maize) and its near isoline (Zong 31, non-Bt maize) by whole plant inspections. Results showed that Bt maize had no effects on non-lepidopteran pest abundance and diversity (Shannon-Wiener diversity index, Simpson's diversity index, species richness, and Pielou's index). There was a significant effect of year and sampling time on those indices analyzed. Redundancy analysis indicated maize type, sampling time and year totally explained 20.43 % of the variance in the non-lepidopteran pest community composition, but no association was presented between maize type (Bt maize and non-Bt maize) and the variance. Nonmetric multidimensional scaling analysis showed that sampling time and year, rather than maize type had close relationship with the non-lepidopteran pest community composition. These results corroborated the hypothesis that, at least in the short-term, the transgenic cry1Ie maize had negligible effects on the non-lepidopteran pest abundance, diversity and community composition.

  16. Estimating abundance

    USGS Publications Warehouse

    Sutherland, Chris; Royle, Andy

    2016-01-01

    This chapter provides a non-technical overview of ‘closed population capture–recapture’ models, a class of well-established models that are widely applied in ecology, such as removal sampling, covariate models, and distance sampling. These methods are regularly adopted for studies of reptiles, in order to estimate abundance from counts of marked individuals while accounting for imperfect detection. Thus, the chapter describes some classic closed population models for estimating abundance, with considerations for some recent extensions that provide a spatial context for the estimation of abundance, and therefore density. Finally, the chapter suggests some software for use in data analysis, such as the Windows-based program MARK, and provides an example of estimating abundance and density of reptiles using an artificial cover object survey of Slow Worms (Anguis fragilis).

  17. Ecological communities with Lotka-Volterra dynamics

    NASA Astrophysics Data System (ADS)

    Bunin, Guy

    2017-04-01

    Ecological communities in heterogeneous environments assemble through the combined effect of species interaction and migration. Understanding the effect of these processes on the community properties is central to ecology. Here we study these processes for a single community subject to migration from a pool of species, with population dynamics described by the generalized Lotka-Volterra equations. We derive exact results for the phase diagram describing the dynamical behaviors, and for the diversity and species abundance distributions. A phase transition is found from a phase where a unique globally attractive fixed point exists to a phase where multiple dynamical attractors exist, leading to history-dependent community properties. The model is shown to possess a symmetry that also establishes a connection with other well-known models.

  18. Ecological communities with Lotka-Volterra dynamics.

    PubMed

    Bunin, Guy

    2017-04-01

    Ecological communities in heterogeneous environments assemble through the combined effect of species interaction and migration. Understanding the effect of these processes on the community properties is central to ecology. Here we study these processes for a single community subject to migration from a pool of species, with population dynamics described by the generalized Lotka-Volterra equations. We derive exact results for the phase diagram describing the dynamical behaviors, and for the diversity and species abundance distributions. A phase transition is found from a phase where a unique globally attractive fixed point exists to a phase where multiple dynamical attractors exist, leading to history-dependent community properties. The model is shown to possess a symmetry that also establishes a connection with other well-known models.

  19. Cost-Effective Stress Management Training.

    ERIC Educational Resources Information Center

    Shea, Gordon F.

    1980-01-01

    Stress management training can be a cost effective way to improve productivity and job performance. Among many relaxation techniques, the most effective in terms of teachability, participant motivation, and profitability are self-hypnosis, progressive relaxation, and transcendental meditation. (SK)

  20. Cost-Effectiveness of Old and New Technologies for Aneuploidy Screening.

    PubMed

    Sinkey, Rachel G; Odibo, Anthony O

    2016-06-01

    Cost-effectiveness analyses allow assessment of whether marginal gains from new technology are worth increased costs. Several studies have examined cost-effectiveness of Down syndrome (DS) screening and found it to be cost-effective. Noninvasive prenatal screening also appears to be cost-effective among high-risk women with respect to DS screening, but not for the general population. Chromosomal microarray (CMA) is a genetic sequencing method superior to but more expensive than karyotype. In light of CMAs greater ability to detect genetic abnormalities, it is cost-effective when used for prenatal diagnosis of an anomalous fetus. This article covers methodology and salient issues of cost-effectiveness. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Preceding crop affects soybean aphid abundance and predator-prey dynamics in soybean

    USDA-ARS?s Scientific Manuscript database

    Crop rotations alter the soil environment and physiology of the subsequent crop in ways that may affect herbivore abundance. Soybean aphids are a consistent pest of soybean throughout North America, but little work has focused on how preceding crops may affect aphid populations. In a replicated expe...

  2. The comparative effectiveness and cost-effectiveness of ranibizumab for neovascular macular degeneration revisited.

    PubMed

    Brown, Gary C; Brown, Melissa M; Lieske, Heidi B; Turpcu, Adam; Rajput, Yamina

    2017-01-01

    To compare a near decade of follow-up, newer control cohort data, use of both the societal and third party insurer cost perspectives, and integration of unilateral/bilateral therapy on the comparative effectiveness and cost-effectiveness of intravitreal ranibizumab therapy for neovascular, age-related macular degeneration (AMD). Value-Based Medicine ® , 12-year, combined-eye model, cost-utility analysis employing MARINA and HORIZON clinical trial data. Preference-based comparative effectiveness outcomes were quantified in (1) QALY (quality-adjusted life-year) gain, and (2) percent improvement in quality-of-life, while cost-effectiveness outcomes were quantified in (3) the cost-utility ratio (CUR) and financial return-on-investment (ROI) to society. Using MARINA and HORIZON trial data and a meta-analysis control cohort after 24 months, ranibizumab therapy conferred a combined-eye patient value (quality-of-life) gain of 16.3%, versus 10.4% found in 2006. The two-year direct ophthalmic medical cost for ranibizumab therapy was $46,450, a 33.8% real dollar decrease from 2006. The societal cost perspective CUR was -$242,920/QALY, indicating a $282,517 financial return-on-investment (ROI), or 12.3%/year to society for direct ophthalmic medical costs expended. The 3rd party insurer CUR ranged from $21,199/QALY utilizing all direct, medical costs, to $69,591/QALY using direct ophthalmic medical costs. Ranibizumab therapy for neovascular AMD in 2015, considering treatment of both eyes, conferred greater patient value gain (comparative effectiveness) and improved cost-effectiveness than in 2006, as well as a large monetary return-on-investment to the Gross Domestic Product and nation's wealth. The model herein integrates important novel features for neovascular age-related macular degeneration, vitreoretinal cost effectiveness analyses, including: (1) treatment of both eyes, (2) a long-term, untreated control cohort, and (3) the use of societal costs.

  3. Cost-effectiveness in fall prevention for older women.

    PubMed

    Hektoen, Liv F; Aas, Eline; Lurås, Hilde

    2009-08-01

    The aim of this study was to estimate the cost-effectiveness of implementing an exercise-based fall prevention programme for home-dwelling women in the > or = 80-year age group in Norway. The impact of the home-based individual exercise programme on the number of falls is based on a New Zealand study. On the basis of the cost estimates and the estimated reduction in the number of falls obtained with the chosen programme, we calculated the incremental costs and the incremental effect of the exercise programme as compared with no prevention. The calculation of the average healthcare cost of falling was based on assumptions regarding the distribution of fall injuries reported in the literature, four constructed representative case histories, assumptions regarding healthcare provision associated with the treatment of the specified cases, and estimated unit costs from Norwegian cost data. We calculated the average healthcare costs per fall for the first year. We found that the reduction in healthcare costs per individual for treating fall-related injuries was 1.85 times higher than the cost of implementing a fall prevention programme. The reduction in healthcare costs more than offset the cost of the prevention programme for women aged > or = 80 years living at home, which indicates that health authorities should increase their focus on prevention. The main intention of this article is to stipulate costs connected to falls among the elderly in a transparent way and visualize the whole cost picture. Cost-effectiveness analysis is a health policy tool that makes politicians and other makers of health policy conscious of this complexity.

  4. Modeling the relationship between water level, wild rice abundance, and waterfowl abundance at a central North American wetland

    USGS Publications Warehouse

    Aagaard, Kevin; Eash, Josh D.; Ford, Walt; Heglund, Patricia J.; McDowell, Michelle; Thogmartin, Wayne E.

    2018-01-01

    Recent evidence suggests wild rice (Zizania palustris), an important resource for migrating waterfowl, is declining in parts of central North America, providing motivation to rigorously quantify the relationship between waterfowl and wild rice. A hierarchical mixed-effects model was applied to data on waterfowl abundance for 16 species, wild rice stem density, and two measures of water depth (true water depth at vegetation sampling locations and water surface elevation). Results provide evidence for an effect of true water depth (TWD) on wild rice abundance (posterior mean estimate for TWD coefficient, β TWD = 0.92, 95% confidence interval = 0.11—1.74), but not for an effect of wild rice stem density or water surface elevation on local waterfowl abundance (posterior mean values for relevant parameters overlapped 0). Refined protocols for sampling design and more consistent sampling frequency to increase data quality should be pursued to overcome issues that may have obfuscated relationships evaluated here.

  5. Thresholds for the cost-effectiveness of interventions: alternative approaches.

    PubMed

    Marseille, Elliot; Larson, Bruce; Kazi, Dhruv S; Kahn, James G; Rosen, Sydney

    2015-02-01

    Many countries use the cost-effectiveness thresholds recommended by the World Health Organization's Choosing Interventions that are Cost-Effective project (WHO-CHOICE) when evaluating health interventions. This project sets the threshold for cost-effectiveness as the cost of the intervention per disability-adjusted life-year (DALY) averted less than three times the country's annual gross domestic product (GDP) per capita. Highly cost-effective interventions are defined as meeting a threshold per DALY averted of once the annual GDP per capita. We argue that reliance on these thresholds reduces the value of cost-effectiveness analyses and makes such analyses too blunt to be useful for most decision-making in the field of public health. Use of these thresholds has little theoretical justification, skirts the difficult but necessary ranking of the relative values of locally-applicable interventions and omits any consideration of what is truly affordable. The WHO-CHOICE thresholds set such a low bar for cost-effectiveness that very few interventions with evidence of efficacy can be ruled out. The thresholds have little value in assessing the trade-offs that decision-makers must confront. We present alternative approaches for applying cost-effectiveness criteria to choices in the allocation of health-care resources.

  6. Simple and cost-effective fluorescent labeling of 5-hydroxymethylcytosine

    NASA Astrophysics Data System (ADS)

    Shahal, Tamar; Green, Ori; Hananel, Uri; Michaeli, Yael; Shabat, Doron; Ebenstein, Yuval

    2016-12-01

    The nucleobase 5-hydroxymethylcytosine (5-hmC), a modified form of cytosine, is an important epigenetic mark related to regulation of gene expression. 5-hmC levels are highly dynamic during early development and are modulated during the progression of neurodegenerative disease and cancer. We describe a spectroscopic method for the global quantification of 5-hmC in genomic DNA. This method relies on the enzymatic glucosylation of 5-hmC, followed by a glucose oxidation step that results in the formation of aldehyde moieties that are covalently linked to a fluorescent reporter by oxime ligation. The fluorescence intensity of the labeled sample is directly proportional to its 5-hmC content. We show that this simple and cost-effective technique is suitable for quantification of 5-hmC content in different mouse tissues.

  7. Effect of atomic parameters on determination of aluminium abundance in atmospheres of late-type stars

    NASA Astrophysics Data System (ADS)

    Menzhevitski, V. S.; Shimanskaya, N. N.; Shimansky, V. V.; Kudryavtsev, D. O.

    2014-04-01

    We study the effect of the photoionization cross sections for the ground state of Al I on the inferred aluminium abundance in stellar atmospheres. We match the theoretical and observed line profiles of the resonance λλ 3944.01, 3961.52 Å and subordinate λλ 6696.03, 6698.68 Å doublets in high-resolution spectra of the metal-poor solar-type stars HD22879 and HD201889. We determine the parameters of these stars from their photometric and spectroscopic data. Our computations show that the profiles can be matched and a single aluminium abundance inferred simultaneously from both groups of spectral lines only with low photoionization cross sections (about 10-12 Mb). Larger cross sections (about 58-65 Mb) make such fits impossible. We therefore conclude that small photoionization cross sections should be preferred for the determination of aluminium abundances in metal-poor stars. We redetermine the aluminium abundances in the atmospheres of halo stars. The resulting abundances prove to be lower by 0.1-0.15 dex than our earlier determinations which does not affect the conclusions based on our earlier estimates. In particular, the NLTE [Al/Fe]-[Fe/H] dependence, on the whole, agrees only qualitatively with the results of theoretical predictions. Therefore further refinement of the theory of nuclear synthesis of aluminium in the process of the chemical evolution of the Galaxy remains a task of current importance.

  8. Cost-effective targeting of conservation investments to reduce the northern Gulf of Mexico hypoxic zone.

    PubMed

    Rabotyagov, Sergey S; Campbell, Todd D; White, Michael; Arnold, Jeffrey G; Atwood, Jay; Norfleet, M Lee; Kling, Catherine L; Gassman, Philip W; Valcu, Adriana; Richardson, Jeffrey; Turner, R Eugene; Rabalais, Nancy N

    2014-12-30

    A seasonally occurring summer hypoxic (low oxygen) zone in the northern Gulf of Mexico is the second largest in the world. Reductions in nutrients from agricultural cropland in its watershed are needed to reduce the hypoxic zone size to the national policy goal of 5,000 km(2) (as a 5-y running average) set by the national Gulf of Mexico Task Force's Action Plan. We develop an integrated assessment model linking the water quality effects of cropland conservation investment decisions on the more than 550 agricultural subwatersheds that deliver nutrients into the Gulf with a hypoxic zone model. We use this integrated assessment model to identify the most cost-effective subwatersheds to target for cropland conservation investments. We consider targeting of the location (which subwatersheds to treat) and the extent of conservation investment to undertake (how much cropland within a subwatershed to treat). We use process models to simulate the dynamics of the effects of cropland conservation investments on nutrient delivery to the Gulf and use an evolutionary algorithm to solve the optimization problem. Model results suggest that by targeting cropland conservation investments to the most cost-effective location and extent of coverage, the Action Plan goal of 5,000 km(2) can be achieved at a cost of $2.7 billion annually. A large set of cost-hypoxia tradeoffs is developed, ranging from the baseline to the nontargeted adoption of the most aggressive cropland conservation investments in all subwatersheds (estimated to reduce the hypoxic zone to less than 3,000 km(2) at a cost of $5.6 billion annually).

  9. The Cost-Effectiveness of NBPTS Teacher Certification

    ERIC Educational Resources Information Center

    Yeh, Stuart S.

    2010-01-01

    A cost-effectiveness analysis of the National Board for Professional Teaching Standards (NBPTS) program suggests that Board certification is less cost-effective than a range of alternative approaches for raising student achievement, including comprehensive school reform, class size reduction, a 10% increase in per pupil expenditure, the use of…

  10. A review of systematic reviews of the cost-effectiveness of hormone therapy, chemotherapy, and targeted therapy for breast cancer.

    PubMed

    Diaby, Vakaramoko; Tawk, Rima; Sanogo, Vassiki; Xiao, Hong; Montero, Alberto J

    2015-05-01

    Breast cancer is a global health concern. In fact, breast cancer is the primary cause of death among women worldwide and constitutes the most expensive malignancy to treat. As health care resources are finite, decisions regarding the adoption and coverage of breast cancer treatments are increasingly being based on "value for money," i.e., cost-effectiveness. As the evidence about the cost-effectiveness of breast cancer treatments is abundant, therefore difficult to navigate, systematic reviews of published systematic reviews offer the advantage of bringing together the results of separate systematic reviews in a single report. As a consequence, this paper presents an overview of systematic reviews of the cost-effectiveness of hormone therapy, chemotherapy, and targeted therapy for breast cancer to inform policy and reimbursement decision-making. A systematic review was conducted of published systematic reviews documenting cost-effectiveness analyses of breast cancer treatments from 2000 to 2014. Systematic reviews identified through a literature search of health and economic databases were independently assessed against inclusion and exclusion criteria. Systematic reviews of original evaluations were included only if they targeted breast cancer patients and specific breast cancer treatments (hormone therapy, chemotherapy, and targeted therapy only), documented incremental cost-effectiveness ratios, and were reported in the English language. The search strategy used a combination of these key words: "breast cancer," "systematic review/meta-analysis," and "cost-effectiveness/economics." Data were extracted using predefined extraction forms and qualitatively appraised using the assessment of multiple systematic reviews (AMSTAR) tool. The literature search resulted in 511 bibliographic records, of which ten met our inclusion criteria. Five reviews were conducted in the early-stage breast cancer setting and five reviews in the metastatic setting. In early-stage breast

  11. A review of systematic reviews of the cost-effectiveness of hormone therapy, chemotherapy, and targeted therapy for breast cancer

    PubMed Central

    Diaby, Vakaramoko; Xiao, Hong; Montero, Alberto J.

    2015-01-01

    Breast cancer is a global health concern. In fact, breast cancer is the primary cause of death among women worldwide and constitutes the most expensive malignancy to treat. As health care resources are finite, decisions regarding the adoption and coverage of breast cancer treatments are increasingly being based on “value for money,” i.e., cost-effectiveness. As the evidence about the cost-effectiveness of breast cancer treatments is abundant, therefore difficult to navigate, systematic reviews of published systematic reviews offer the advantage of bringing together the results of separate systematic reviews in a single report. As a consequence, this paper presents an overview of systematic reviews of the cost-effectiveness of hormone therapy, chemotherapy, and targeted therapy for breast cancer to inform policy and reimbursement decision-making. A systematic review was conducted of published systematic reviews documenting cost-effectiveness analyses of breast cancer treatments from 2000 to 2014. Systematic reviews identified through a literature search of health and economic databases were independently assessed against inclusion and exclusion criteria. Systematic reviews of original evaluations were included only if they targeted breast cancer patients and specific breast cancer treatments (hormone therapy, chemotherapy, and targeted therapy only), documented incremental cost-effectiveness ratios, and were reported in the English language. The search strategy used a combination of these key words: “breast cancer,” “systematic review/meta-analysis,” and “cost-effectiveness/economics.” Data were extracted using predefined extraction forms and qualitatively appraised using the assessment of multiple systematic reviews (AMSTAR) tool. The literature search resulted in 511 bibliographic records, of which ten met our inclusion criteria. Five reviews were conducted in the early-stage breast cancer setting and five reviews in the metastatic setting. In

  12. Commentary: demonstrating cost-effectiveness in pediatric psychology.

    PubMed

    McGrady, Meghan E

    2014-07-01

    Changes in the health care system and payment plans will likely require pediatric psychologists to illustrate the impact of their services. Cost-effectiveness analyses are one method of demonstrating the potential economic benefits of our services but are rarely used by pediatric psychologists. A hypothetical cost-effectiveness analysis was conducted, comparing the costs and outcomes between a behavioral adherence intervention and no intervention for youth with acute lymphoblastic leukemia. Results illustrate how pediatric psychologists can use cost-effectiveness analyses to demonstrate the economic impact of their work. Efforts to conduct economic analyses could allow pediatric psychologists to advocate for their services. Implications and future directions are discussed. © The Author 2014. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Economics of mycotoxins: evaluating costs to society and cost-effectiveness of interventions.

    PubMed

    2012-01-01

    The economic impacts of mycotoxins to human society can be thought of in two ways: (i) the direct market costs associated with lost trade or reduced revenues due to contaminated food or feed, and (ii) the human health losses from adverse effects associated with mycotoxin consumption. Losses related to markets occur within systems in which mycotoxins are being monitored in the food and feed supply. Food that has mycotoxin levels above a particular maximum allowable level is either rejected outright for sale or sold at a lower price for a different use. Such transactions can take place at local levels or at the level of trade among countries. Sometimes this can result in heavy economic losses for food producers, but the benefit of such monitoring systems is a lower risk of mycotoxins in the food supply. Losses related to health occur when mycotoxins are present in food at levels that can cause illness. In developed countries, such losses are often measured in terms of cost of illness; around the world, such losses are more frequently measured in terms of disability-adjusted life years (DALYs). It is also useful to assess the economics of interventions to reduce mycotoxins and their attendant health effects; the relative effectiveness of public health interventions can be assessed by estimating quality-adjusted life years (QALYs) associated with each intervention. Cost-effectiveness assessment can be conducted to compare the cost of implementing the intervention with the resulting benefits, in terms of either improved markets or improved human health. Aside from cost-effectiveness, however, it is also important to assess the technical feasibility of interventions, particularly in low-income countries, where funds and infrastructures are limited.

  14. The cost-effectiveness of psychotherapy

    PubMed Central

    Lazar, Susan G.; Gabbard, Glen O.

    1997-01-01

    Recent studies suggest that psychotherapy can be cost-effective, especially for certain patient populations. These patients include, among others, those with schizophrenia, those with borderline personality disorder, and certain child patients, as well as certain medical patients with concomitant psychiatric illness. In addition, several surveys and actuarial studies suggest better outcomes and cost savings are attained when psychotherapy is available as medically necessary without arbitrary restrictions. PMID:9292445

  15. Effects of reforestation on ammonia-oxidizing microbial community composition and abundance in subtropical acidic forest soils.

    PubMed

    Wu, Ruo-Nan; Meng, Han; Wang, Yong-Feng; Gu, Ji-Dong

    2018-06-01

    Forest ecosystems have great ecological values in mitigation of climate change and protection of biodiversity of flora and fauna; re-forestry is commonly used to enhance the sequestration of atmospheric CO 2 into forest storage biomass. Therefore, seasonal and spatial dynamics of the major microbial players in nitrification, ammonia-oxidizing archaea (AOA) and bacteria (AOB), in acidic soils of young and matured revegetated forests were investigated to elucidate the changes of microbial communities during forest restoration, and compared to delineate the patterns of community shifts under the influences of environmental factors. AOA were more abundant than AOB in both young and matured revegetated forest soils in both summer and winter seasons. In summer, however, the abundance of amoA-AOA decreased remarkably (p < 0.01), ranging from 1.90 (± 0.07) × 10 8 copies per gram dry soil in matured forest to 5.04 (± 0.43) × 10 8 copies per gram dry soil in young forest, and amoA-AOB was below detection limits to obtain any meaningful values. Moreover, exchangeable Al 3+ and organic matter were found to regulate the physiologically functional nitrifiers, especially AOA abundance in acidic forest soils. AOB community in winter showed stronger correlation with the restoration status of revegetated forests and AOA community dominated by Nitrosotalea devanaterra, in contrast, was more sensitive to the seasonal and spatial variations of environmental factors. These results enrich the current knowledge of nitrification during re-forestry and provide valuable information to developmental status of revegetated forests for management through microbial analysis.

  16. Costs and benefits of trap-neuter-release and euthanasia for removal of urban cats in Oahu, Hawaii.

    PubMed

    Lohr, Cheryl A; Cox, Linda J; Lepczyk, Christopher A

    2013-02-01

    Our goal was to determine whether it is more cost-effective to control feral cat abundance with trap-neuter-release programs or trap and euthanize programs. Using STELLA 7, systems modeling software, we modeled changes over 30 years in abundance of cats in a feral colony in response to each management method and the costs and benefits associated with each method . We included costs associated with providing food, veterinary care, and microchips to the colony cats and the cost of euthanasia, wages, and trapping equipment in the model. Due to a lack of data on predation rates and disease transmission by feral cats the only benefits incorporated into the analyses were reduced predation on Wedge-tailed Shearwaters (Puffinus pacificus). When no additional domestic cats were abandoned by owners and the trap and euthanize program removed 30,000 cats in the first year, the colony was extirpated in at least 75% of model simulations within the second year. It took 30 years for trap-neuter-release to extirpate the colony. When the cat population was supplemented with 10% of the initial population size per year, the colony returned to carrying capacity within 6 years and the trap and euthanize program had to be repeated, whereas trap-neuter-release never reduced the number of cats to near zero within the 30-year time frame of the model. The abandonment of domestic cats reduced the cost effectiveness of both trap-neuter-release and trap and euthanize. Trap-neuter-release was approximately twice as expensive to implement as a trap and euthanize program. Results of sensitivity analyses suggested trap-neuter-release programs that employ volunteers are still less cost-effective than trap and euthanize programs that employ paid professionals and that trap-neuter-release was only effective when the total number of colony cats in an area was below 1000. Reducing the rate of abandonment of domestic cats appears to be a more effective solution for reducing the abundance of feral cats.

  17. Cost-Effectiveness of School-Based Prevention of Cannabis Use.

    PubMed

    Deogan, Charlotte; Zarabi, Natalie; Stenström, Nils; Högberg, Pi; Skärstrand, Eva; Manrique-Garcia, Edison; Neovius, Kristian; Månsdotter, Anna

    2015-10-01

    Cannabis is the most frequently used illicit drug globally. Despite increasing evidence that cannabis use is associated with adverse health effects, the knowledge on preventative strategies is still limited. This study stemmed from a systematic review of effective prevention in which school-based programmes were identified as promising. The primary objective was to evaluate the cost effectiveness of Project ALERT (Adolescent, Learning, Experiences, Resistance, and Training), compared with ordinary ATOD (Alcohol, Tobacco, and Other Drug) education, among Swedish students in the eighth grade of compulsory school. The cost-effectiveness analysis was performed from the societal perspective with quality-adjusted life-years (QALYs) as an outcome (willingness-to-pay threshold €50,000) and follow-up periods from 1 year to a lifetime, considering a discounting rate of 3%, and with costs inflated to 2013 levels. A Markov model was constructed on the basis of the 'states' of single use, regular use, daily use and use of other illicit drugs, which were associated with 'complications' of psychosis, schizophrenia, traffic accidents, depression and amotivational syndrome. Health and cost consequences were linked to both states and complications. The programme was cost saving on the basis of evidence from the USA (ratio 1:1.1), and was cost effective (incremental cost-effectiveness ratio €22,384 per QALY) after reasonable adjustment for the Swedish context and with 20 years of follow-up. When the target group was restricted to boys who were neither studying nor working/doing work experience, the programme was cost effective after 9 years and cost saving (ratio 1:3.2) after 20 years. School-based prevention such as Project ALERT has the potential to be cost effective and to be cost saving if implemented in deprived areas. In the light of the shifting landscape regarding legalization of cannabis, it seems rational to continue the health economic analysis of prevention initiated

  18. Long-term change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean.

    PubMed

    Bailey, D M; Ruhl, H A; Smith, K L

    2006-03-01

    Food web structure, particularly the relative importance of bottom-up and top-down control of animal abundances, is poorly known for the Earth's largest habitats: the abyssal plains. A unique 15-yr time series of climate, productivity, particulate flux, and abundance of primary consumers (primarily echinoderms) and secondary consumers (fish) was examined to elucidate the response of trophic levels to temporal variation in one another. Towed camera sled deployments in the abyssal northeast Pacific (4100 m water depth) showed that annual mean numbers of the dominant fish genus (Coryphaenoides spp.) more than doubled over the period 1989-2004. Coryphaenoides spp. abundance was significantly correlated with total abundance of mobile epibenthic megafauna (echinoderms), with changes in fish abundance lagging behind changes in the echinoderms. Direct correlations between surface climate and fish abundances, and particulate organic carbon (POC) flux and fish abundances, were insignificant, which may be related to the varied response of the potential prey taxa to climate and POC flux. This study provides a rare opportunity to study the long-term dynamics of an unexploited marine fish population and suggests a dominant role for bottom-up control in this system.

  19. A cost-effectiveness comparison of embryo donation with oocyte donation.

    PubMed

    Finger, Reginald; Sommerfelt, Carol; Freeman, Melanie; Wilson, Carrie K; Wade, Amy; Daly, Douglas

    2010-02-01

    To compare the cost-effectiveness of embryo donation (ED) to that of oocyte donation (OD). Calculation of cost-effectiveness ratios (costs per outcome achieved) using data derived from clinical practices. In vitro fertilization centers and embryo donation programs. Infertile couples undergoing oocyte donation or embryo donation. Oocyte donation or embryo donation cycles. Cost-effectiveness ratios. For a single cycle, ED is approximately twice as cost-effective as OD, with a cost-effectiveness ratio of $21,990 per live delivery compared to 40,600 dollars. When strategies of up to three cycles (to achieve one live delivery) are used, ED costs 13,505 dollars per live delivery compared to 31,349 dollars for OD. Cost-effectiveness is a compelling reason for infertile couples to consider embryo donation. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  20. Cost effective technology

    NASA Astrophysics Data System (ADS)

    Miller, S. C.

    1989-09-01

    With relation to advanced technology for gas turbines, the overall process of product definition and development, concentrating particularly on the integration of activities between engineering design and manufacturing, is surveyed. The development of new philosophies in each of these spheres of activity is concluded to be cost effective technology and to make a highly significant contribution to the competitiveness and profitability of the industry.

  1. Supported employment: cost-effectiveness across six European sites

    PubMed Central

    Knapp, Martin; Patel, Anita; Curran, Claire; Latimer, Eric; Catty, Jocelyn; Becker, Thomas; Drake, Robert E; Fioritti, Angelo; Kilian, Reinhold; Lauber, Christoph; Rössler, Wulf; Tomov, Toma; van Busschbach, Jooske; Comas-Herrera, Adelina; White, Sarah; Wiersma, Durk; Burns, Tom

    2013-01-01

    A high proportion of people with severe mental health problems are unemployed but would like to work. Individual Placement and Support (IPS) offers a promising approach to establishing people in paid employment. In a randomized controlled trial across six European countries, we investigated the economic case for IPS for people with severe mental health problems compared to standard vocational rehabilitation. Individuals (n=312) were randomized to receive either IPS or standard vocational services and followed for 18 months. Service use and outcome data were collected. Cost-effectiveness analysis was conducted with two primary outcomes: additional days worked in competitive settings and additional percentage of individuals who worked at least 1 day. Analyses distinguished country effects. A partial cost-benefit analysis was also conducted. IPS produced better outcomes than alternative vocational services at lower cost overall to the health and social care systems. This pattern also held in disaggregated analyses for five of the six European sites. The inclusion of imputed values for missing cost data supported these findings. IPS would be viewed as more cost-effective than standard vocational services. Further analysis demonstrated cost-benefit arguments for IPS. Compared to standard vocational rehabilitation services, IPS is, therefore, probably cost-saving and almost certainly more cost-effective as a way to help people with severe mental health problems into competitive employment. PMID:23471803

  2. Cost-effectiveness of detecting and treating diabetic retinopathy.

    PubMed

    Javitt, J C; Aiello, L P

    1996-01-01

    To determine, from the health insurer's perspective, the cost of preventing vision loss in patients with diabetes mellitus through ophthalmologic screening and treatment and to calculate the cost-effectiveness of these interventions as compared with that of other medical interventions. Computer modeling, incorporating data from population-based epidemiologic studies and multicenter clinical trials. Monte Carlo simulation was used, combined with sensitivity analysis and present value analysis of cost savings. Screening and treatment of eye disease in patients with diabetes mellitus costs $3190 per quality-adjusted life-year (QALY) saved. This average cost is a weighted average (based on prevalence disease) of the cost-effectiveness of detecting and treating diabetic eye disease in those with insulin-dependent diabetes mellitus ($1996 per QALY), those with non-insulin-dependent diabetes mellitus (NIDDM) who use insulin for glycemic control ($2933 per QALY), and those with NIDDM who do not use insulin for glycemic control ($3530 per QALY). Our analysis indicates that prevention programs aimed at improving eye care for diabetic persons not only result in substantial federal budgetary savings but are highly cost-effective health investments for society. Ophthalmologic screening for diabetic persons is more cost-effective than many routinely provided health interventions. Because diabetic eye disease is the leading cause of new cases of blindness among working-age Americans, these results support the widespread use of screening and treatment for diabetic eye disease.

  3. An improved set of standards for finding cost for cost-effectiveness analysis.

    PubMed

    Barnett, Paul G

    2009-07-01

    Guidelines have helped standardize methods of cost-effectiveness analysis, allowing different interventions to be compared and enhancing the generalizability of study findings. There is agreement that all relevant services be valued from the societal perspective using a long-term time horizon and that more exact methods be used to cost services most affected by the study intervention. Guidelines are not specific enough with respect to costing methods, however. The literature was reviewed to identify the problems associated with the 4 principal methods of cost determination. Microcosting requires direct measurement and is ordinarily reserved to cost novel interventions. Analysts should include nonwage labor cost, person-level and institutional overhead, and the cost of development, set-up activities, supplies, space, and screening. Activity-based cost systems have promise of finding accurate costs of all services provided, but are not widely adopted. Quality must be evaluated and the generalizability of cost estimates to other settings must be considered. Administrative cost estimates, chiefly cost-adjusted charges, are widely used, but the analyst must consider items excluded from the available system. Gross costing methods determine quantity of services used and employ a unit cost. If the intervention will affect the characteristics of a service, the method should not assume that the service is homogeneous. Questions are posed for future reviews of the quality of costing methods. The analyst must avoid inappropriate assumptions, especially those that bias the analysis by exclusion of costs that are affected by the intervention under study.

  4. Cost-Effectiveness Analysis of Qsymia for Weight Loss.

    PubMed

    Finkelstein, Eric A; Kruger, Eliza; Karnawat, Sunil

    2015-07-01

    Phase 3 clinical trial results reveal that Qsymia is a clinically effective long-term treatment for obesity, but whether this treatment is cost-effective compared to a diet and lifestyle intervention has yet to be explored. To quantify the incremental cost-effectiveness of Qsymia (phentermine and topiramate extended-release) for health-related quality of life improvements. Estimates are based on cost and quality of life outcomes from a 56-week, multicenter, placebo-controlled, phase 3 clinical trial undertaken in 93 health centers in the US. Participants were overweight and obese adults (aged 18-70 years) with a body-mass index of 27-45 kg/m(2) and two or more comorbidities (hypertension, dyslipidemia, diabetes or pre-diabetes or abdominal obesity). The intervention was diet and lifestyle advice plus the recommended dose of Qsymia (phentermine 7.5 mg plus topiramate 46.0 mg) vs. control, which included diet and lifestyle advice plus placebo. The study was from the payer perspective. Costs included the prescription cost, medication cost offsets and physician appointment costs. Effectiveness was measured in terms of quality-adjusted life years gained (QALYs). The main outcome measure was incremental cost per QALY gained of the intervention relative to control. Our base-case model, in which participants take Qsymia for 1 year with benefits linearly decaying over the subsequent 2 years, generates an incremental cost-effectiveness ratio (ICER) of $48,340 per QALY gained. Using the base-case assumptions, probabilistic sensitivity analyses reveal that the ICER is below $50,000 per QALY in 54 % of simulations. However, results are highly dependent on the extent to which benefits are maintained post medication cessation. If benefits persist for only 1 year post cessation, the ICER increases to $74,480. Although base-case results suggest that Qsymia is cost-effective, this result hinges on the time on Qsymia and the extent to which benefits are maintained post

  5. Can delivery systems use cost-effectiveness analysis to reduce healthcare costs and improve value?

    PubMed

    Savitz, Lucy A; Savitz, Samuel T

    2016-01-01

    Understanding costs and ensuring that we demonstrate value in healthcare is a foundational presumption as we transform the way we deliver and pay for healthcare in the U.S. With a focus on population health and payment reforms underway, there is increased pressure to examine cost-effectiveness in healthcare delivery. Cost-effectiveness analysis (CEA) is a type of economic analysis comparing the costs and effects (i.e. health outcomes) of two or more treatment options. The result is expressed as a ratio where the denominator is the gain in health from a measure (e.g. years of life or quality-adjusted years of life) and the numerator is the incremental cost associated with that health gain. For higher cost interventions, the lower the ratio of costs to effects, the higher the value. While CEA is not new, the approach continues to be refined with enhanced statistical techniques and standardized methods. This article describes the CEA approach and also contrasts it to optional approaches, in order for readers to fully appreciate caveats and concerns. CEA as an economic evaluation tool can be easily misused owing to inappropriate assumptions, over reliance, and misapplication. Twelve issues to be considered in using CEA results to drive healthcare delivery decision-making are summarized. Appropriately recognizing both the strengths and the limitations of CEA is necessary for informed resource allocation in achieving the maximum value for healthcare services provided.

  6. The cost effectiveness of intracyctoplasmic sperm injection (ICSI).

    PubMed

    Hollingsworth, Bruce; Harris, Anthony; Mortimer, Duncan

    2007-12-01

    To estimate the incremental cost effectiveness of ICSI, and total costs for the population of Australia. Treatment effects for three patient groups were drawn from a published systematic review and meta-analysis of trials comparing fertilisation outcomes for ICSI. Incremental costs derived from resource-based costing of ICSI and existing practice comparators for each patient group. Incremental cost per live birth for patients unsuited to IVF is estimated between A$8,500 and 13,400. For the subnormal semen indication, cost per live birth could be as low as A$3,600, but in the worst case scenario, there would just be additional incremental costs of A$600 per procedure. Multiplying out the additional costs of ICSI over the relevant target populations in Australia gives potential total financial implications of over A$31 million per annum. While there are additional benefits from ICSI procedure, particularly for those with subnormal sperm, the additional cost for the health care system is substantial.

  7. Cost-effectiveness analysis of treatments for premenstrual dysphoric disorder.

    PubMed

    Rendas-Baum, Regina; Yang, Min; Gricar, Joseph; Wallenstein, Gene V

    2010-01-01

    Premenstrual syndrome (PMS) is reported to affect between 13% and 31% of women. Between 3% and 8% of women are reported to meet criteria for the more severe form of PMS, premenstrual dysphoric disorder (PMDD). Although PMDD has received increased attention in recent years, the cost effectiveness of treatments for PMDD remains unknown. To evaluate the cost effectiveness of the four medications with a US FDA-approved indication for PMDD: fluoxetine, sertraline, paroxetine and drospirenone plus ethinyl estradiol (DRSP/EE). A decision-analytic model was used to evaluate both direct costs (medication and physician visits) and clinical outcomes (treatment success, failure and discontinuation). Medication costs were based on average wholesale prices of branded products; physician visit costs were obtained from a claims database study of PMDD patients and the Agency for Healthcare Research and Quality. Clinical outcome probabilities were derived from published clinical trials in PMDD. The incremental cost-effectiveness ratio (ICER) was calculated using the difference in costs and percentage of successfully treated patients at 6 months. Deterministic and probabilistic sensitivity analyses were used to assess the impact of uncertainty in parameter estimates. Threshold values where a change in the cost-effective strategy occurred were identified using a net benefit framework. Starting therapy with DRSP/EE dominated both sertraline and paroxetine, but not fluoxetine. The estimated ICER of initiating treatment with fluoxetine relative to DRSP/EE was $US4385 per treatment success (year 2007 values). Cost-effectiveness acceptability curves revealed that for ceiling ratios>or=$US3450 per treatment success, fluoxetine had the highest probability (>or=0.37) of being the most cost-effective treatment, relative to the other options. The cost-effectiveness acceptability frontier further indicated that DRSP/EE remained the option with the highest expected net monetary benefit for

  8. Cost-effectiveness of pulse-echo ultrasonometry in osteoporosis management.

    PubMed

    Soini, Erkki; Riekkinen, Ossi; Kröger, Heikki; Mankinen, Petri; Hallinen, Taru; Karjalainen, Janne P

    2018-01-01

    Osteoporosis is asymptomatic morbidity of the elderly which develops slowly over several years. Osteoporosis diagnosis has typically involved Fracture Risk Assessment (FRAX) followed by dual energy X-ray absorptiometry (DXA) in specialist care. Point-of-care pulse-echo ultrasound (PEUS) was developed to overcome DXA-related access issues and to enable faster fracture prevention treatment (FPT) initiation. The objective of this study was to evaluate the cost-effectiveness of two proposed osteoporosis management (POMs: FRAX→PEUS-if-needed→DXA-if-needed→FPT-if-needed) pathways including PEUS compared with the current osteoporosis management (FRAX→DXA-if-needed→FPT-if-needed). Event-based probabilistic cost-utility model with 10-year duration for osteoporosis management was developed. The model consists of a decision tree for the screening, testing, and diagnosis phase and is followed by a Markov model for the estimation of incidence of four fracture types and mortality. Five clinically relevant patient cohorts (potential primary FPT in women aged 75 or 85 years, secondary FPT in women aged 65, 75, or 85 years) were modeled in the Finnish setting. Generic alendronate FPT was used for those diagnosed with osteoporosis, including persistence overtime. Discounted (3%/year) incremental cost-effectiveness ratio was the primary outcome. Discounted quality-adjusted life-years (QALYs), payer costs (year 2016 value) at per patient and population level, and cost-effectiveness acceptability frontiers were modeled as secondary outcomes. POMs were cost-effective in all patient subgroups with noteworthy mean per patient cost savings of €121/76 (ranges €107-132/52-96) depending on the scope of PEUS result interpretation (test and diagnose/test only, respectively) and negligible differences in QALYs gained in comparison with current osteoporosis management. In the cost-effectiveness acceptability frontiers, POMs had 95%-100% probability of cost-effectiveness with

  9. Prescribed fire and timber harvest effects on terrestrial salamander abundance, detectability, and microhabitat use

    Treesearch

    Katherine M. O' Donnell; Frank R. Thompson; Raymond D. Semlitsch

    2015-01-01

    Prescribed fire and timber harvest are anthropogenic disturbances that modify resource availability and ecosystem structure, and can affect wildlife both directly and indirectly. Terrestrial salamanders are effective indicators of forest health due to their high abundance and sensitivity to microclimatic conditions. Given their ecological importance, it is critical to...

  10. Cost-effectiveness model for prevention of early childhood caries.

    PubMed

    Ramos-Gomez, F J; Shepard, D S

    1999-07-01

    This study presents and illustrates a model that determines the cost-effectiveness of three successively more complete levels of preventive intervention (minimal, intermediate, and comprehensive) in treating dental caries in disadvantaged children up to 6 years of age. Using existing data on the costs of early childhood caries (ECC), the authors estimated the probable cost-effectiveness of each of the three preventive intervention levels by comparing treatment costs to prevention costs as applied to a typical low-income California child for five years. They found that, in general, prevention becomes cost-saving if at least 59 percent of carious lesions receive restorative treatment. Assuming an average restoration cost of $112 per surface, the model predicts cost savings of $66 to $73 in preventing a one-surface, carious lesion. Thus, all three levels of preventive intervention should be relatively cost-effective. Comprehensive intervention would provide the greatest oral health benefit; however, because more children would receive reparative care, overall program costs would rise even as per-child treatment costs decline.

  11. Temporal Changes Rather than Long-Term Repeated Burning Predominately Control the Shift in the Abundance of Soil Denitrifying Community in an Australian Sclerophyll Forest.

    PubMed

    Liu, Xian; Chen, C R; Hughes, J M; Wang, W J; Lewis, Tom

    2017-01-01

    To understand the temporal dynamics of soil bacterial denitrifying community in response to long-term prescribed burning and its resilience and recovery following a fire, a wet sclerophyll forest study site under two treatments (2 yearly burning (2YB) and no burning (NB)) and with 40-year-old burning history was used. Similar temporal patterns in the abundance of total (16S rRNA) and denitrifying (narG, nirK, nirS, nosZ) bacteria between two burning treatments revealed strong temporal influences. The magnitude of burning impacts on the abundance of 16S rRNA and denitrification genes was smaller compared with the impact of sampling time, but significant burning and temporal impacts were recorded for all (P < 0.001)-except for the nirS gene. Impacts of prescribed fire on the abundance of soil denitrifying community could be observed immediately after fire, and this impact diminished over a 24-month period prior to the next prescribed burning event. In conclusion, temporal changes govern the fluctuations of the abundance of soil denitrifying genes over the sampling period and the denitrifying community can recover after fire, suggesting that this community is resilient to the effects of prescribed burning. A combination of biotic and abiotic factors may account for the different temporal dynamics of denitrification gene abundance.

  12. Ecological evaluation of the abundance and effects of elk herbivory in Rocky Mountain National Park, Colorado, 1994-1999

    USGS Publications Warehouse

    Singer, Francis J.; Zeigenfuss, Linda C.

    2002-01-01

    Several National Park Service units in the Intermountain region possess a number of closely related management needs relative to the abundance of wild ungulates and their herbivory effects on plants and ecosystem processes. In 1993, the then National Biological Service (NBS) - now U.S. Geological Survey, Biological Resources Discipline (USGS, BRD)­ initiated a series of research studies in four park units in the Intermountain West., into the abundance and effects of ungulates on park ecosystems. Each of these parks received a number of similar research study elements including: (a) a number of new ungulate grazing exclosures (n = 12-21 exclosures per park); (b) aerial survey sightability models to estimate population sizes of ungulates; (e) measures of biomass production and consumption rates near the exclosures and across the landscape; (d) studies of the effects of the grazing on plant abundance, species diversity, and ecosystem effects; and (e) computer model simulations (SAVANNA) of the effects on the ecosystem and plant resources of different ungulate management scenarios. One park unit, Rocky Mountain National Park, Colorado, received funding from the U.S. Geological Survey (USGS, BRD) and parallel funding from NPS for an intensive research study of the effects of elk on the park ecosystems.

  13. Vaccinating women previously exposed to human papillomavirus: a cost-effectiveness analysis of the bivalent vaccine.

    PubMed

    Turner, Hugo C; Baussano, Iacopo; Garnett, Geoff P

    2013-01-01

    Recent trials have indicated that women with prior exposure to Human papillomavirus (HPV) subtypes 16/18 receive protection against reinfection from the HPV vaccines. However, many of the original models investigating the cost effectiveness of different vaccination strategies for the protection of cervical cancer assumed, based on the trial results at that time, that these women received no protection. We developed a deterministic, dynamic transmission model that incorporates the vaccine-induced protection of women with prior exposure to HPV. The model was used to estimate the cost effectiveness of progressively extending a vaccination programme using the bivalent vaccine to older age groups both with and without protection of women with prior exposure. We did this under a range of assumptions on the level of natural immunity. Our modelling projections indicate that including the protection of women with prior HPV exposure can have a profound effect on the cost effectiveness of vaccinating adults. The impact of this protection is inversely related to the level of natural immunity. Our results indicate that adult vaccination strategies should potentially be reassessed, and that it is important to include the protection of non-naive women previously infected with HPV in future studies. Furthermore, they also highlight the need for a more thorough investigation of this protection.

  14. Cost-Effectiveness of the Freeze-All Policy.

    PubMed

    Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

    2015-08-01

    To evaluate the cost-effectiveness of freeze-all cycles when compared to fresh embryo transfer. This was an observational study with a cost-effectiveness analysis. The analysis consisted of 530 intracytoplasmic sperm injection (ICSI) cycles in a private center in Brazil between January 2012 and December 2013. A total of 530 intracytoplasmic sperm injection (ICSI) cycles - 351 fresh embryo transfers and 179 freeze-all cycles - with a gonadotropin-releasing hormone (GnRH) antagonist protocol and day 3 embryo transfers. The pregnancy rate was 31.1% in the fresh group and 39.7% in the freeze-all group. We performed two scenario analyses for costs. In scenario 1, we included those costs associated with the ICSI cycle (monitoring during controlled ovarian stimulation [COS], oocyte retrieval, embryo transfer, IVF laboratory, and medical costs), embryo cryopreservation of supernumerary embryos, hormone measurements during COS and endometrial priming, medication use (during COS, endometrial priming, and luteal phase support), ultrasound scan for frozen- thawed embryo transfer (FET), obstetric ultrasounds, and miscarriage. The total cost (in USD) per pregnancy was statistically lower in the freeze-all cycles (19,156.73 ± 1,732.99) when compared to the fresh cycles (23,059.72 ± 2,347.02). Even in Scenario 2, when charging all of the patients in the freeze-all group for cryopreservation (regardless of supernumerary embryos) and for FET, the fresh cycles had a statistically significant increase in treatment costs per ongoing pregnancy. The results presented in this study suggest that the freeze-all policy is a cost-effective strategy when compared to fresh embryo transfer.

  15. Pheromone production, male abundance, body size, and the evolution of elaborate antennae in moths

    PubMed Central

    Symonds, Matthew RE; Johnson, Tamara L; Elgar, Mark A

    2012-01-01

    The males of some species of moths possess elaborate feathery antennae. It is widely assumed that these striking morphological features have evolved through selection for males with greater sensitivity to the female sex pheromone, which is typically released in minute quantities. Accordingly, females of species in which males have elaborate (i.e., pectinate, bipectinate, or quadripectinate) antennae should produce the smallest quantities of pheromone. Alternatively, antennal morphology may be associated with the chemical properties of the pheromone components, with elaborate antennae being associated with pheromones that diffuse more quickly (i.e., have lower molecular weights). Finally, antennal morphology may reflect population structure, with low population abundance selecting for higher sensitivity and hence more elaborate antennae. We conducted a phylogenetic comparative analysis to test these explanations using pheromone chemical data and trapping data for 152 moth species. Elaborate antennae are associated with larger body size (longer forewing length), which suggests a biological cost that smaller moth species cannot bear. Body size is also positively correlated with pheromone titre and negatively correlated with population abundance (estimated by male abundance). Removing the effects of body size revealed no association between the shape of antennae and either pheromone titre, male abundance, or mean molecular weight of the pheromone components. However, among species with elaborate antennae, longer antennae were typically associated with lower male abundances and pheromone compounds with lower molecular weight, suggesting that male distribution and a more rapidly diffusing female sex pheromone may influence the size but not the general shape of male antennae. PMID:22408739

  16. Depleting high-abundant and enriching low-abundant proteins in human serum: An evaluation of sample preparation methods using magnetic nanoparticle, chemical depletion and immunoaffinity techniques.

    PubMed

    de Jesus, Jemmyson Romário; da Silva Fernandes, Rafael; de Souza Pessôa, Gustavo; Raimundo, Ivo Milton; Arruda, Marco Aurélio Zezzi

    2017-08-01

    The efficiency of three different depletion methods to remove the most abundant proteins, enriching those human serum proteins with low abundance is checked to make more efficient the search and discovery of biomarkers. These methods utilize magnetic nanoparticles (MNPs), chemical reagents (sequential application of dithiothreitol and acetonitrile, DTT/ACN), and commercial apparatus based on immunoaffinity (ProteoMiner, PM). The comparison between methods shows significant removal of abundant protein, remaining in the supernatant at concentrations of 4.6±0.2, 3.6±0.1, and 3.3±0.2µgµL -1 (n=3) for MNPs, DTT/ACN and PM respectively, from a total protein content of 54µgµL -1 . Using GeLC-MS/MS analysis, MNPs depletion shows good efficiency in removing high molecular weight proteins (>80kDa). Due to the synergic effect between the reagents DTT and ACN, DTT/ACN-based depletion offers good performance in the depletion of thiol-rich proteins, such as albumin and transferrin (DTT action), as well as of high molecular weight proteins (ACN action). Furthermore, PM equalization confirms its efficiency in concentrating low-abundant proteins, decreasing the dynamic range of protein levels in human serum. Direct comparison between the treatments reveals 72 proteins identified when using MNP depletion (43 of them exclusively by this method), but only 20 proteins using DTT/ACN (seven exclusively by this method). Additionally, after PM treatment 30 proteins were identified, seven exclusively by this method. Thus, MNPs and DTT/ACN depletion can be simple, quick, cheap, and robust alternatives for immunochemistry-based protein depletion, providing a potential strategy in the search for disease biomarkers. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. New Earth-abundant Materials for Large-scale Solar Fuels Generation.

    PubMed

    Prabhakar, Rajiv Ramanujam; Cui, Wei; Tilley, S David

    2018-05-30

    The solar resource is immense, but the power density of light striking the Earth's surface is relatively dilute, necessitating large area solar conversion devices in order to harvest substantial amounts of power for renewable energy applications. In addition, energy storage is a key challenge for intermittent renewable resources such as solar and wind, which adds significant cost to these energies. As the majority of humanity's present-day energy consumption is based on fuels, an ideal solution is to generate renewable fuels from abundant resources such as sunlight and water. In this account, we detail our recent work towards generating highly efficient and stable Earth-abundant semiconducting materials for solar water splitting to generate renewable hydrogen fuel.

  18. Projection Effects of Large-scale Structures on Weak-lensing Peak Abundances

    NASA Astrophysics Data System (ADS)

    Yuan, Shuo; Liu, Xiangkun; Pan, Chuzhong; Wang, Qiao; Fan, Zuhui

    2018-04-01

    High peaks in weak lensing (WL) maps originate dominantly from the lensing effects of single massive halos. Their abundance is therefore closely related to the halo mass function and thus a powerful cosmological probe. However, besides individual massive halos, large-scale structures (LSS) along lines of sight also contribute to the peak signals. In this paper, with ray-tracing simulations, we investigate the LSS projection effects. We show that for current surveys with a large shape noise, the stochastic LSS effects are subdominant. For future WL surveys with source galaxies having a median redshift z med ∼ 1 or higher, however, they are significant. For the cosmological constraints derived from observed WL high-peak counts, severe biases can occur if the LSS effects are not taken into account properly. We extend the model of Fan et al. by incorporating the LSS projection effects into the theoretical considerations. By comparing with simulation results, we demonstrate the good performance of the improved model and its applicability in cosmological studies.

  19. A cost-effective method to prepare curcumin nanosuspensions with enhanced oral bioavailability.

    PubMed

    Wang, Yutong; Wang, Changyuan; Zhao, Jing; Ding, Yanfang; Li, Lei

    2017-01-01

    Nanosuspension is one of the most promising strategies to improve the oral bioavailability of insoluble drugs. The existing techniques applied to produce nanosuspensions are classified as "bottom-up" or "top-down" methods, or a combination of both. Curcumin (CUR), a Biopharmaceutics Classification System (BCS) class IV substance, is a promising drug candidate in view of its good bioactivity, but its use is limited due to its poor solubility and permeability. In the present study, CUR nanosuspensions were developed to enhance CUR oral bioavailability using a cost-effective method different from conventional techniques. The physicochemical properties of CUR nanosuspensions were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The crystalline state of CUR in different nanosuspensions analyzed using differential scanning calorimeter (DSC) and X-ray diffraction analysis (PXRD) confirmed its amorphous state. In vitro dissolution degree of the prepared CUR nanosuspensions using TPGS or Brij78 as stabilizer was greatly increased. Pharmacokinetic studies demonstrated that the oral bioavailability of CUR was increased 3.18 and 3.7 times after administration of CUR/TPGS nanosuspensions or CUR/Brij78 nanosuspensions, when compared with the administration of CUR suspension. CUR nanosuspensions produced by our cost-effective method could improve its oral bioavailability. In addition, the low-cost and time-saving method reported here is highly suitable for a fast and inexpensive preparation. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. The cost and cost-effectiveness of rapid testing strategies for yaws diagnosis and surveillance.

    PubMed

    Fitzpatrick, Christopher; Asiedu, Kingsley; Sands, Anita; Gonzalez Pena, Tita; Marks, Michael; Mitja, Oriol; Meheus, Filip; Van der Stuyft, Patrick

    2017-10-01

    Yaws is a non-venereal treponemal infection caused by Treponema pallidum subspecies pertenue. The disease is targeted by WHO for eradication by 2020. Rapid diagnostic tests (RDTs) are envisaged for confirmation of clinical cases during treatment campaigns and for certification of the interruption of transmission. Yaws testing requires both treponemal (trep) and non-treponemal (non-trep) assays for diagnosis of current infection. We evaluate a sequential testing strategy (using a treponemal RDT before a trep/non-trep RDT) in terms of cost and cost-effectiveness, relative to a single-assay combined testing strategy (using the trep/non-trep RDT alone), for two use cases: individual diagnosis and community surveillance. We use cohort decision analysis to examine the diagnostic and cost outcomes. We estimate cost and cost-effectiveness of the alternative testing strategies at different levels of prevalence of past/current infection and current infection under each use case. We take the perspective of the global yaws eradication programme. We calculate the total number of correct diagnoses for each strategy over a range of plausible prevalences. We employ probabilistic sensitivity analysis (PSA) to account for uncertainty and report 95% intervals. At current prices of the treponemal and trep/non-trep RDTs, the sequential strategy is cost-saving for individual diagnosis at prevalence of past/current infection less than 85% (81-90); it is cost-saving for surveillance at less than 100%. The threshold price of the trep/non-trep RDT (below which the sequential strategy would no longer be cost-saving) is US$ 1.08 (1.02-1.14) for individual diagnosis at high prevalence of past/current infection (51%) and US$ 0.54 (0.52-0.56) for community surveillance at low prevalence (15%). We find that the sequential strategy is cost-saving for both diagnosis and surveillance in most relevant settings. In the absence of evidence assessing relative performance (sensitivity and specificity