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Sample records for models downy woodpecker

  1. Genetic signals of demographic expansion in Downy Woodpecker (Picoides pubescens after the last North American glacial maximum.

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    Paulo C Pulgarín-R

    Full Text Available The glacial cycles of the Pleistocene have been recognized as important, large-scale historical processes that strongly influenced the demographic patterns and genetic structure of many species. Here we present evidence of a postglacial expansion for the Downy Woodpecker (Picoides pubescens, a common member of the forest bird communities in North America with a continental distribution. DNA sequences from the mitochondrial tRNA-Lys, and ATPase 6 and 8 genes, and microsatellite data from seven variable loci were combined with a species distribution model (SDM to infer possible historical scenarios for this species after the last glacial maximum. Analyses of Downy Woodpeckers from 23 geographic areas suggested little differentiation, shallow genealogical relationships, and limited population structure across the species' range. Microsatellites, which have higher resolution and are able to detect recent differences, revealed two geographic groups where populations along the eastern edge of the Rocky Mountains (Montana, Utah, Colorado, and southern Alberta were genetically isolated from the rest of the sampled populations. Mitochondrial DNA, an important marker to detect historical patterns, recovered only one group. However, populations in Idaho and southeast BC contained high haplotype diversity and, in general were characterized by the absence of the most common mtDNA haplotype. The SDM suggested several areas in the southern US as containing suitable Downy Woodpecker habitat during the LGM. The lack of considerable geographic structure and the starburst haplotype network, combined with several population genetic tests, suggest a scenario of demographic expansion during the last part of Pleistocene and early Holocene.

  2. Transferability of habitat suitability models for nesting woodpeckers associated with wildfire

    Science.gov (United States)

    Quresh S. Latif; Vicki Saab; Jeff P. Hollenbeck; Jonathan G. Dudley

    2016-01-01

    Following wildfire, forest managers are challenged with meeting both socioeconomic demands (e.g., salvage logging) and mandates requiring habitat conservation for disturbance-associated wildlife (e.g., woodpeckers). Habitat suitability models for nesting woodpeckers can be informative, but tests of model transferability are needed to understand how broadly...

  3. Development of a disease risk prediction model for downy mildew (Peronospora sparsa) in boysenberry.

    Science.gov (United States)

    Kim, Kwang Soo; Beresford, Robert M; Walter, Monika

    2014-01-01

    Downy mildew caused by Peronospora sparsa has resulted in serious production losses in boysenberry (Rubus hybrid), blackberry (Rubus fruticosus), and rose (Rosa sp.) in New Zealand, Mexico, and the United States and the United Kingdom, respectively. Development of a model to predict downy mildew risk would facilitate development and implementation of a disease warning system for efficient fungicide spray application in the crops affected by this disease. Because detailed disease observation data were not available, a two-step approach was applied to develop an empirical risk prediction model for P. sparsa. To identify the weather patterns associated with a high incidence of downy mildew berry infections (dryberry disease) and derive parameters for the empirical model, classification and regression tree (CART) analysis was performed. Then, fuzzy sets were applied to develop a simple model to predict the disease risk based on the parameters derived from the CART analysis. High-risk seasons with a boysenberry downy mildew incidence >10% coincided with months when the number of hours per day with temperature of 15 to 20°C averaged >9.8 over the month and the number of days with rainfall in the month was >38.7%. The Fuzzy Peronospora Sparsa (FPS) model, developed using fuzzy sets, defined relationships among high-risk events, temperature, and rainfall conditions. In a validation study, the FPS model provided correct identification of both seasons with high downy mildew risk for boysenberry, blackberry, and rose and low risk in seasons when no disease was observed. As a result, the FPS model had a significant degree of agreement between predicted and observed risks of downy mildew for those crops (P = 0.002).

  4. Epidemiology and population biology of pseudoperonospora cubensis: a model system for management of downy mildews

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    The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of disease outbreaks. Dispersal potential of th...

  5. Improving inferences from short-term ecological studies with Bayesian hierarchical modeling: white-headed woodpeckers in managed forests.

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    Linden, Daniel W; Roloff, Gary J

    2015-08-01

    Pilot studies are often used to design short-term research projects and long-term ecological monitoring programs, but data are sometimes discarded when they do not match the eventual survey design. Bayesian hierarchical modeling provides a convenient framework for integrating multiple data sources while explicitly separating sample variation into observation and ecological state processes. Such an approach can better estimate state uncertainty and improve inferences from short-term studies in dynamic systems. We used a dynamic multistate occupancy model to estimate the probabilities of occurrence and nesting for white-headed woodpeckers Picoides albolarvatus in recent harvest units within managed forests of northern California, USA. Our objectives were to examine how occupancy states and state transitions were related to forest management practices, and how the probabilities changed over time. Using Gibbs variable selection, we made inferences using multiple model structures and generated model-averaged estimates. Probabilities of white-headed woodpecker occurrence and nesting were high in 2009 and 2010, and the probability that nesting persisted at a site was positively related to the snag density in harvest units. Prior-year nesting resulted in higher probabilities of subsequent occurrence and nesting. We demonstrate the benefit of forest management practices that increase the density of retained snags in harvest units for providing white-headed woodpecker nesting habitat. While including an additional year of data from our pilot study did not drastically alter management recommendations, it changed the interpretation of the mechanism behind the observed dynamics. Bayesian hierarchical modeling has the potential to maximize the utility of studies based on small sample sizes while fully accounting for measurement error and both estimation and model uncertainty, thereby improving the ability of observational data to inform conservation and management strategies.

  6. Integration of Long-Term Research into a GIS Based Landscape Habitat Model for the Red-Cockaded Woodpecker

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    Franzreb, K.; Lloyd, F.T.

    2000-10-01

    The red cockaded woodpecker has been intensively studied since 1985 when the population was on the verge of extinction. The population decline is primarily the result of timber harvesting prior to 1950 and restricted burning. Construction of artificial cavities, translocations, competitor control, and removal of hardwood mid-story has provided suitable habitat. Since 1985, the population has increased from 4 to 99 birds. A GIS model is being developed to simulate the development of habitat at SRS in relation to management and existing vegetation.

  7. Predicting the risk of cucurbit downy mildew in the eastern United States using an integrated aerobiological model

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    Neufeld, K. N.; Keinath, A. P.; Gugino, B. K.; McGrath, M. T.; Sikora, E. J.; Miller, S. A.; Ivey, M. L.; Langston, D. B.; Dutta, B.; Keever, T.; Sims, A.; Ojiambo, P. S.

    2017-11-01

    Cucurbit downy mildew caused by the obligate oomycete, Pseudoperonospora cubensis, is considered one of the most economically important diseases of cucurbits worldwide. In the continental United States, the pathogen overwinters in southern Florida and along the coast of the Gulf of Mexico. Outbreaks of the disease in northern states occur annually via long-distance aerial transport of sporangia from infected source fields. An integrated aerobiological modeling system has been developed to predict the risk of disease occurrence and to facilitate timely use of fungicides for disease management. The forecasting system, which combines information on known inoculum sources, long-distance atmospheric spore transport and spore deposition modules, was tested to determine its accuracy in predicting risk of disease outbreak. Rainwater samples at disease monitoring sites in Alabama, Georgia, Louisiana, New York, North Carolina, Ohio, Pennsylvania and South Carolina were collected weekly from planting to the first appearance of symptoms at the field sites during the 2013, 2014, and 2015 growing seasons. A conventional PCR assay with primers specific to P. cubensis was used to detect the presence of sporangia in rain water samples. Disease forecasts were monitored and recorded for each site after each rain event until initial disease symptoms appeared. The pathogen was detected in 38 of the 187 rainwater samples collected during the study period. The forecasting system correctly predicted the risk of disease outbreak based on the presence of sporangia or appearance of initial disease symptoms with an overall accuracy rate of 66 and 75%, respectively. In addition, the probability that the forecasting system correctly classified the presence or absence of disease was ≥ 73%. The true skill statistic calculated based on the appearance of disease symptoms in cucurbit field plantings ranged from 0.42 to 0.58, indicating that the disease forecasting system had an acceptable to good

  8. Global variation in woodpecker species richness shaped by tree availability

    DEFF Research Database (Denmark)

    Ilsøe, Sigrid Kistrup; Kissling, W. Daniel; Fjeldså, Jon

    2017-01-01

    heterogeneity and biogeographical region. We further used structural equation models to test for direct and indirect effects of predictor variables. Results: There was a strong positive relationship between woodpecker species richness and current tree cover and annual precipitation, respectively. Precipitation...... a negative indirect effect on woodpecker species richness. Main conclusions: Global species richness of woodpeckers is primarily shaped by current tree cover and precipitation, reflecting a strong biotic association between woodpeckers and trees. Human influence can have a negative effect on woodpecker...... diversity when humans reduce tree availability. Hence, woodpeckers exemplify how broad-scale diversity patterns are predominantly shaped by a biotic factor, and how climate and human influence can have indirect effects on animal biodiversity via the effects on tree availability and forest cover....

  9. Sequencing of the Litchi Downy Blight Pathogen Reveals It Is a Phytophthora Species With Downy Mildew-Like Characteristics.

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    Ye, Wenwu; Wang, Yang; Shen, Danyu; Li, Delong; Pu, Tianhuizi; Jiang, Zide; Zhang, Zhengguang; Zheng, Xiaobo; Tyler, Brett M; Wang, Yuanchao

    2016-07-01

    On the basis of its downy mildew-like morphology, the litchi downy blight pathogen was previously named Peronophythora litchii. Recently, however, it was proposed to transfer this pathogen to Phytophthora clade 4. To better characterize this unusual oomycete species and important fruit pathogen, we obtained the genome sequence of Phytophthora litchii and compared it to those from other oomycete species. P. litchii has a small genome with tightly spaced genes. On the basis of a multilocus phylogenetic analysis, the placement of P. litchii in the genus Phytophthora is strongly supported. Effector proteins predicted included 245 RxLR, 30 necrosis-and-ethylene-inducing protein-like, and 14 crinkler proteins. The typical motifs, phylogenies, and activities of these effectors were typical for a Phytophthora species. However, like the genome features of the analyzed downy mildews, P. litchii exhibited a streamlined genome with a relatively small number of genes in both core and species-specific protein families. The low GC content and slight codon preferences of P. litchii sequences were similar to those of the analyzed downy mildews and a subset of Phytophthora species. Taken together, these observations suggest that P. litchii is a Phytophthora pathogen that is in the process of acquiring downy mildew-like genomic and morphological features. Thus P. litchii may provide a novel model for investigating morphological development and genomic adaptation in oomycete pathogens.

  10. Evaluating habitat suitability models for nesting white-headed woodpeckers in unburned forest

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    Quresh S. Latif; Victoria A. Saab; Kim Mellen-Mclean; Jonathan G. Dudley

    2015-01-01

    Habitat suitability models can provide guidelines for species conservation by predicting where species of interest are likely to occur. Presence-only models are widely used but typically provide only relative indices of habitat suitability (HSIs), necessitating rigorous evaluation often using independently collected presence-absence data. We refined and evaluated...

  11. Using satellite and airborne LiDAR to model woodpecker habitat occupancy at the landscape scale

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    Lee A. Vierling; Kerri T. Vierling; Patrick Adam; Andrew T. Hudak

    2013-01-01

    Incorporating vertical vegetation structure into models of animal distributions can improve understanding of the patterns and processes governing habitat selection. LiDAR can provide such structural information, but these data are typically collected via aircraft and thus are limited in spatial extent. Our objective was to explore the utility of satellite-based LiDAR...

  12. Red-cockaded Woodpecker Picoides borealis Microhabitat Characteristics and Reproductive Success in a Loblolly-Shortleaf Pine Forest

    Science.gov (United States)

    Wood, Douglas R.; Burger, L. Wesley; Vilella, Francisco

    2014-01-01

    We investigated the relationship between red-cockaded woodpecker (Picoides borealis) reproductive success and microhabitat characteristics in a southeastern loblolly (Pinus taeda) and shortleaf (P. echinata) pine forest. From 1997 to 1999, we recorded reproductive success parameters of 41 red-cockaded woodpecker groups at the Bienville National Forest, Mississippi. Microhabitat characteristics were measured for each group during the nesting season. Logistic regression identified understory vegetation height and small nesting season home range size as predictors of red-cockaded woodpecker nest attempts. Linear regression models identified several variables as predictors of red-cockaded woodpecker reproductive success including group density, reduced hardwood component, small nesting season home range size, and shorter foraging distances. Red-cockaded woodpecker reproductive success was correlated with habitat and behavioral characteristics that emphasize high quality habitat. By providing high quality foraging habitat during the nesting season, red-cockaded woodpeckers can successfully reproduce within small home ranges.

  13. Why do woodpeckers resist head impact injury: a biomechanical investigation.

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    Lizhen Wang

    Full Text Available Head injury is a leading cause of morbidity and death in both industrialized and developing countries. It is estimated that brain injuries account for 15% of the burden of fatalities and disabilities, and represent the leading cause of death in young adults. Brain injury may be caused by an impact or a sudden change in the linear and/or angular velocity of the head. However, the woodpecker does not experience any head injury at the high speed of 6-7 m/s with a deceleration of 1000 g when it drums a tree trunk. It is still not known how woodpeckers protect their brain from impact injury. In order to investigate this, two synchronous high-speed video systems were used to observe the pecking process, and the force sensor was used to measure the peck force. The mechanical properties and macro/micro morphological structure in woodpecker's head were investigated using a mechanical testing system and micro-CT scanning. Finite element (FE models of the woodpecker's head were established to study the dynamic intracranial responses. The result showed that macro/micro morphology of cranial bone and beak can be recognized as a major contributor to non-impact-injuries. This biomechanical analysis makes it possible to visualize events during woodpecker pecking and may inspire new approaches to prevention and treatment of human head injury.

  14. Urbanization level and woodland size are major drivers of woodpecker species richness and abundance.

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    Myczko, Lukasz; Rosin, Zuzanna M; Skórka, Piotr; Tryjanowski, Piotr

    2014-01-01

    Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland) in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species.

  15. Urbanization level and woodland size are major drivers of woodpecker species richness and abundance.

    Directory of Open Access Journals (Sweden)

    Lukasz Myczko

    Full Text Available Urbanization is a process globally responsible for loss of biodiversity and for biological homogenization. Urbanization may have a direct negative impact on species behaviour and indirect effects on species populations through alterations of their habitats, for example patch size and habitat quality. Woodpeckers are species potentially susceptible to urbanization. These birds are mostly forest specialists and the development of urban areas in former forests may be an important factor influencing their richness and abundance, but documented examples are rare. In this study we investigated how woodpeckers responded to changes in forest habitats as a consequence of urbanization, namely size and isolation of habitat patches, and other within-patch characteristics. We selected 42 woodland patches in a gradient from a semi-natural rural landscape to the city centre of Poznań (Western Poland in spring 2010. Both species richness and abundance of woodpeckers correlated positively to woodland patch area and negatively to increasing urbanization. Abundance of woodpeckers was also positively correlated with shrub cover and percentage of deciduous tree species. Furthermore, species richness and abundance of woodpeckers were highest at moderate values of canopy openness. Ordination analyses confirmed that urbanization level and woodland patch area were variables contributing most to species abundance in the woodpecker community. Similar results were obtained in presence-absence models for particular species. Thus, to sustain woodpecker species within cities it is important to keep woodland patches large, multi-layered and rich in deciduous tree species.

  16. How does a woodpecker work? An impact dynamics approach

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    Liu, Yuzhe; Qiu, Xinming; Yu, Tongxi; Tao, Jiawei; Cheng, Ze

    2015-04-01

    To understand how a woodpecker is able accelerate its head to such a high velocity in a short amount of time, a multi-rigid-segment model of a woodpecker's body is established in this study. Based on the skeletal specimen of the woodpecker and several videos of woodpeckers pecking, the parameters of a three-degree-of-freedom system are determined. The high velocity of the head is found to be the result of a whipping effect, which could be affected by muscle torque and tendon stiffness. The mechanism of whipping is analyzed by comparing the response of a hinged rod to that of a rigid rod. Depending on the parameters, the dynamic behavior of a hinged rod is classified into three response modes. Of these, a high free-end velocity could be achieved in mode II. The model is then generalized to a multihinge condition, and the free-end velocity is found to increase with hinge number, which explains the high free-end velocity resulting from whipping. Furthermore, the effects of some other factors, such as damping and mass distribution, on the velocity are also discussed.

  17. Distributional changes and range predictions of downy brome (Bromus tectorum) in Rocky Mountain National Park

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    Bromberg, J.E.; Kumar, S.; Brown, C.S.; Stohlgren, T.J.

    2011-01-01

    Downy brome (Bromus tectorum L.), an invasive winter annual grass, may be increasing in extent and abundance at high elevations in the western United States. This would pose a great threat to high-elevation plant communities and resources. However, data to track this species in high-elevation environments are limited. To address changes in the distribution and abundance of downy brome and the factors most associated with its occurrence, we used field sampling and statistical methods, and niche modeling. In 2007, we resampled plots from two vegetation surveys in Rocky Mountain National Park for presence and cover of downy brome. One survey was established in 1993 and had been resampled in 1999. The other survey was established in 1996 and had not been resampled until our study. Although not all comparisons between years demonstrated significant changes in downy brome abundance, its mean cover increased nearly fivefold from 1993 (0.7%) to 2007 (3.6%) in one of the two vegetation surveys (P = 0.06). Although the average cover of downy brome within the second survey appeared to be increasing from 1996 to 2007, this slight change from 0.5% to 1.2% was not statistically significant (P = 0.24). Downy brome was present in 50% more plots in 1999 than in 1993 (P = 0.02) in the first survey. In the second survey, downy brome was present in 30% more plots in 2007 than in 1996 (P = 0.08). Maxent, a species-environmental matching model, was generally able to predict occurrences of downy brome, as new locations were in the ranges predicted by earlier generated models. The model found that distance to roads, elevation, and vegetation community influenced the predictions most. The strong response of downy brome to interannual environmental variability makes detecting change challenging, especially with small sample sizes. However, our results suggest that the area in which downy brome occurs is likely increasing in Rocky Mountain National Park through increased frequency and cover

  18. Experimental reintroduction of red-cockaded woodpeckers

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    D. Craig Rudolph; Richard N. Conner; Dawn K. Carrie; Richard R. Schaefer

    1992-01-01

    The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to the pine forests of the southeastern United States (Jackson 1971). Deforestation and habitat alteration have severely affected Red-cockaded Woodpecker populations; current populations are isolated and most are declining (Jackson 1971, Lennartz et al. 1983, Conner and Rudolph 1989, Costa...

  19. Factors affecting breeding season survival of Red-Headed Woodpeckers in South Carolina.

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    Kilgo, John, C.; Vukovich, Mark

    2011-11-18

    Red-headed woodpecker (Melanerpes erythrocephalus) populations have declined in the United States and Canada over the past 40 years. However, few demographic studies have been published on the species and none have addressed adult survival. During 2006-2007, we estimated survival probabilities of 80 radio-tagged red-headed woodpeckers during the breeding season in mature loblolly pine (Pinus taeda) forests in South Carolina. We used known-fate models in Program MARK to estimate survival within and between years and to evaluate the effects of foliar cover (number of available cover patches), snag density treatment (high density vs. low density), and sex and age of woodpeckers. Weekly survival probabilities followed a quadratic time trend, being lowest during mid-summer, which coincided with the late nestling and fledgling period. Avian predation, particularly by Cooper's (Accipiter cooperii) and sharp-shinned hawks (A. striatus), accounted for 85% of all mortalities. Our best-supported model estimated an 18-week breeding season survival probability of 0.72 (95% CI = 0.54-0.85) and indicated that the number of cover patches interacted with sex of woodpeckers to affect survival; females with few available cover patches had a lower probability of survival than either males or females with more cover patches. At the median number of cover patches available (n = 6), breeding season survival of females was 0.82 (95% CI = 0.54-0.94) and of males was 0.60 (95% CI = 0.42-0.76). The number of cover patches available to woodpeckers appeared in all 3 of our top models predicting weekly survival, providing further evidence that woodpecker survival was positively associated with availability of cover. Woodpecker survival was not associated with snag density. Our results suggest that protection of {ge}0.7 cover patches per ha during vegetation control activities in mature pine forests will benefit survival of this Partners In Flight Watch List species.

  20. Treating downy brome with herbicide and seeding with native shrubs

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    Suzanne Owen; Carolyn Sieg

    2011-01-01

    Downy brome or cheatgrass (Bromus tectorum L.) is one of the most invasive and widespread exotic plants in North America. Downy brome can reduce soil nutrient availability, alter native plant community composition, and increase fire frequencies. The effectiveness of Plateau® imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty...

  1. Global population decline of the Great Slaty Woodpecker (Mulleripicus pulverulentus)

    NARCIS (Netherlands)

    Lammertink, M.; Prawiradilaga, D.M.; Setiorini, U.; Zaw Naing, T.; Duckworth, J.W.; Menken, S.B.J.

    2009-01-01

    The Great Slaty Woodpecker (Mulleripicus pulverulentus) of South and Southeast Asia, the third largest woodpecker species in the world, is currently in the IUCN Red List category of Least Concern. This woodpecker appears associated with old-growth forests, and the rapid reductions in forest cover

  2. Downy Brome: evidence for soil engineering

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    Bromus tectorum L. (downy brome, cheatgrass) is an invasive Eurasian grass largely responsible for landscape level conversion of sagebrush/bunchgrass communities to annual grass dominance. We tested the hypothesis that B. tectorum alters or “engineers” the soil to favor its growth. The hypothesis wa...

  3. Genetic dissection of Lactuca saligna nonhost resistance to downy mildew at various lettuce developmental stages

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    Zhang, N.; Lindhout, P.; Niks, R.E.; Jeuken, M.J.W.

    2009-01-01

    This study used the pathosystem of lettuce (Lactuca spp.) and downy mildew (Bremia lactucae) as a model to investigate the inheritance of nonhost resistance, and focused on the contribution of quantitative trait loci (QTLs) to nonhost resistance at various developmental stages in the lettuce life

  4. Analysis of microsatellites from the transcriptome of downy mildew pathogens and their application for characterization of Pseudoperonospora populations

    Directory of Open Access Journals (Sweden)

    Emma C. Wallace

    2017-05-01

    Full Text Available Downy mildew pathogens affect several economically important crops worldwide but, due to their obligate nature, few genetic resources are available for genomic and population analyses. Draft genomes for emergent downy mildew pathogens such as the oomycete Pseudoperonospora cubensis, causal agent of cucurbit downy mildew, have been published and can be used to perform comparative genomic analysis and develop tools such as microsatellites to characterize pathogen population structure. We used bioinformatics to identify 2,738 microsatellites in the P. cubensis predicted transcriptome and evaluate them for transferability to the hop downy mildew pathogen, Pseudoperonospora humuli, since no draft genome is available for this species. We also compared the microsatellite repertoire of P. cubensis to that of the model organism Hyaloperonospora arabidopsidis, which causes downy mildew in Arabidopsis. Although trends in frequency of motif-type were similar, the percentage of SSRs identified from P. cubensis transcripts differed significantly from H. arabidopsidis. The majority of a subset of microsatellites selected for laboratory validation (92% produced a product in P. cubensis isolates, and 83 microsatellites demonstrated transferability to P. humuli. Eleven microsatellites were found to be polymorphic and consistently amplified in P. cubensis isolates. Analysis of Pseudoperonospora isolates from diverse hosts and locations revealed higher diversity in P. cubensis compared to P. humuli isolates. These microsatellites will be useful in efforts to better understand relationships within Pseudoperonospora species and P. cubensis on a population level.

  5. Phenology of exotic invasive weeds associated with downy brome

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    The exotic and highly invasive annual grass downy brome (Bromus tectorum) has invaded millions of hectares of rangelands throughout the Intermountain West. Downy brome increases the chance, rate, season and spread of wildfires, resulting in the destruction of native plant communities and the wildli...

  6. Population level response of downy brome to soil growing medium

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    Downy brome (Bromus tectorum) is the most ubiquitous exotic invasive weed in the Intermountain West. A major issue for management is the extreme generalist plastic nature of downy brome. We hypothesized that soil growing medium would effect all measured response variables representing some degree of...

  7. Integrated management of downy brome in winter wheat

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    Downy brome (Bromus tectorum L.), also known as cheatgrass, was introduced into North America from the Mediterranean area of Europe. It was first identified in the eastern United States in 1861, and by 1914 this invasive weed had spread throughout the continent. Downy brome is adapted to climates wi...

  8. Downy brome seed ecology: From flower to emergence

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    Downy brome (Bromus tectorum) seed is very common in seed banks throughout Great Basin rangelands. Previously, using a soil bioassay method, we tested 100 separate sites within the Great Basin (1000 samples) to measure downy brome seed bank densities. The locations differed greatly by precipitation,...

  9. Epidemiology and control of spinach downy mildew in coastal California

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    The most serious threat to global fresh market spinach production is spinach downy mildew, caused by the obligate biotrophic pathogen, Peronospora effusa. Downy mildew causes yellow chlorotic lesions on spinach leaf tissue, often accompanied by abundant sporulation on the undersides of leaves. Very ...

  10. Tapping the woodpecker tree for evolutionary insight.

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    Shakya, Subir B; Fuchs, Jérôme; Pons, Jean-Marc; Sheldon, Frederick H

    2017-11-01

    Molecular phylogenetic studies of woodpeckers (Picidae) have generally focused on relationships within specific clades or have sampled sparsely across the family. We compared DNA sequences of six loci from 203 of the 217 recognized species of woodpeckers to construct a comprehensive tree of intrafamilial relationships. We recovered many known, but also numerous unknown, relationships among clades and species. We found, for example, that the three picine tribes are related as follows (Picini, (Campephilini, Melanerpini)) and that the genus Dinopium is paraphyletic. We used the tree to analyze rates of diversification and biogeographic patterns within the family. Diversification rate increased on two occasions during woodpecker history. We also tested diversification rates between temperate and tropical species but found no significant difference. Biogeographic analysis supported an Old World origin of the family and identified at least six independent cases of New World-Old World sister relationships. In light of the tree, we discuss how convergence, mimicry, and potential cases of hybridization have complicated woodpecker taxonomy. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Looking out for the pileated woodpecker.

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    Noreen Parks

    2009-01-01

    The pileated woodpecker is a species of conservation concern and a keystone species in mature and old forests of the Pacific Northwest. In the Blue Mountains of northeast Oregon, researchers from the PNW Research Station in La Grande, Oregon, studied the effects of natural and human-caused disturbance on pileated populations and their habitat over a period spanning...

  12. Burning and chopping for woodpeckers and wiregrass?

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    Joan L. Walker; Brian P. van Eerden; David Robinson; Mike Hausch

    2004-01-01

    To restore red-cockaded woodpecker habitat managers must reduce hardwoods while maintaining native ground cover. Fire, chemical, and mechanical methods are used alone or in combination to reduce oaks. Previous studies have reported selected single treatment effects (e.g., Outcalt and Lewis 1990, Robbins and Myers 1992, Glitzenstein et al. 1995, Provencher et al. 2001...

  13. Diagnosis method of cucumber downy mildew with NIR hyperspectral imaging

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    Tian, Youwen; Li, Tianlai; Zhang, Lin; Zhang, Xiaodong

    2011-11-01

    This study was carried out to develop a hyperspectral imaging system in the near infrared (NIR) region (900-1700 nm) to diagnose cucumber downy mildew. Hyperspectral images were acquired from each diseased cucumber leaf samples with downy mildew and then their spectral data were extracted. Spectral data were analyzed using principal component analysis (PCA) to reduce the high dimensionality of the data and for selecting some important wavelengths. Out of 256 wavelengths, only two wavelengths (1426 and 1626nm) of first PC were selected as the optimum wavelengths for the diagnosis of cucumber downy mildew. The data analysis showed that it is possible to diagnose cucumber downy mildew with few numbers of wavelengths on the basis of their statistical image features and histogram features. The results revealed the potentiality of NIR hyperspectral imaging as an objective and non-destructive method for the authentication and diagnosis of cucumber downy mildew.

  14. AFLP studies on downy-mildew-resistant and downy-mildew ...

    Indian Academy of Sciences (India)

    Downy mildew (DM) caused by Peronospora arborescens, is a serious disease in opium poppy (Papaver somniferum), which has a world-wide spread. The establishment of DM-resistant cultivars appears to be a sustainable way to control the disease. In this paper, we present the results of a study aimed at the identification ...

  15. AFLP studies on downy-mildew-resistant and downy-mildew ...

    Indian Academy of Sciences (India)

    between DM-resistant and DM-susceptible opium poppy genotypes and development of DM-resistant opium poppy genotype- specific AFLP ... Keywords. AFLP; disease resistance; DNA markers; downy mildew; Papaver somniferum; Peronospora arborescens. ...... 1996 Identification of molecular markers in soybean.

  16. Downy mildews on ornamental plants and their control.

    Science.gov (United States)

    Skrzypczak, C

    2006-01-01

    Among downy mildews occurring on ornamentals in Poland the most dangerous are downy mildew of rose and downy mildew of German statice (Tartarian statice). Downy mildew of rose caused by Peronospora sparsa Berk. is a serious threat to commercial cultivation of cut roses, especially grown under plastic tunnels. Peronospora statices Lobik casual agent of German statice downy mildew can causes the total losses in the second year of statice cultivation more than 70%. Both pathogens are very difficult to control. Effectiveness of azoxystrobine, cymoxanil + famoxate, mancozeb, phosethyl aluminium, phosethyl aluminium + fenamidone, propamocarb in the control of P. sparsa and P. statices was presented. In the control of statice downy mildew none of tested compounds was able to control satisfactory the pathogen. Relatively the best results were obtained with mixture of fenamidone (88 microg/cm3) and phosethyl AL (1334 microg/cm3). In the control of rose downy mildew, the best results were obtained with phosethyl Al at concentration 1600 microg/cm3.

  17. Studies on the reproductive biology of downy brome (Bromus tectorum)

    International Nuclear Information System (INIS)

    Richardson, J.M.

    1986-01-01

    The ability of downy brome to successfully infest crop lands is partially due to its prolific nature. To better understand its reproductive biology, studies investigating (1) effects of temperature and photoperiod on flowering, (2) prevention of downy brome seed information with herbicides, and (3) effects of drought on reproduction, were conducted. Seedling vernalization was more effective than seed vernalization in promoting downy brome flowering. Vernalizing imbibed downy brome caryopses at 3 C for 0 to 30 days did not induce rapid flowering. Downy brome seedlings were exposed to six photoperiod/temperature treatments. After transfer to long days, plants from the short da/3 C treatment flowered within 30 days. DPX-Y6202 and fluazifop-butyl were tested for their ability to prevent seed formation in downy brome. Fluazifop-butyl prevented seed formation over a wider range of application rates and growth stages than did DPX-Y6202. Seed production was prevented most readily by herbicide applications made early in the reproductive cycle. Translocation of radiolabel was greater with 14 C-fluazifop-butyl than with 14 C-DPX-Y6202, particularly into developing spikelets. Microautoradiographic techniques were used to identify mechanisms involved in the prevention of downy brome seed formation by these herbicides. Tissue localization of both herbicides was similar. The highest concentration of radiolabel was found in developing pollen grains, suggesting that the herbicides prevented seed formation by interrupting pollen development or function. Water stress reduced apparent photosynthesis and increased diffusive resistance of flag leaves

  18. Forest habitat loss, fragmentation, and red-cockaded woodpecker populations

    Science.gov (United States)

    Richard N. Conner; D. Craig Rudolph

    1991-01-01

    Loss of mature forest habitat was measured around Red-cockaded Woodpecker (Picoides borealis) cavity tree clusters (colonies) in three National Forests in eastern Texas. Forest removal results in a loss of foraging habitat and causes habitat fragmentation of the remaining mature forest. Habitat loss was negatively associated with woodpecker group size in small...

  19. Population trends of red-cockaded woodpeckers in Texas

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph

    2006-01-01

    tracked population trends of Red-cockaded Woodpeckers (Picoides borealis) in eastern Texas from 1983 through 2004. After declining precipitously during the 1980s, woodpecker population trends on federal lands (National Forests and Grasslands in Texas, but excluding the Big Thicket National Preserve) increased between 1990 and 2000, and have been...

  20. Effects of gypsy moth outbreaks on North American woodpeckers

    Science.gov (United States)

    Walter D. Koenig; Eric L. Walters; Andrew M. Liebhold

    2011-01-01

    We examined the effects of the introduced gypsy moth (Lymantria dispar) on seven species of North American woodpeckers by matching spatially explicit data on gypsy moth outbreaks with data on breeding and wintering populations. In general, we detected modest effects during outbreaks: during the breeding season one species, the Red-headed Woodpecker...

  1. Foraging ecology of pileated woodpeckers in coastal forests of Washington.

    Science.gov (United States)

    C.M. Raley; K.B. Aubry

    2006-01-01

    Providing habitat for pileated woodpeckers in the Pacific Northwest has been a key component of forest management strategies for over 20 years. We investigated the diet of pileated woodpeckers, and selection by birds of both individual structure and site characteristics for foraging. Birds foraged amost exclusively in closed-canopy habitats and selected relatively tall...

  2. Relative importance of social factors, conspecific density, and forest structure on space use by the endangered Red-cockaded Woodpecker: A new consideration for habitat restoration

    Energy Technology Data Exchange (ETDEWEB)

    Garabedian, James E. [Fisheries, Wildlife, and Conservation Biology Program, North Carolina State University, Raleigh, North Carolina, USA; Moorman, Christopher E. [Fisheries, Wildlife, and Conservation Biology Program, North Carolina State University, Raleigh, North Carolina, USA; Peterson, M. Nils [Fisheries, Wildlife, and Conservation Biology Program, North Carolina State University, Raleigh, North Carolina, USA; Kilgo, John C. [Southern Research Station, USDA Forest Service, Savannah River, New Ellenton, South Carolina, USA

    2018-03-14

    Understanding how the interplay between social behaviors and habitat structure influences space use is important for conservation of birds in restored habitat. We integrated fine-grained LiDAR-derived habitat data, spatial distribution of cavity trees, and spatially explicit behavioral observations in a multi-scale model to determine the relative importance of conspecific density, intraspecific interactions, and the distribution of cavities on space use by Red-cockaded Woodpeckers (Picoides borealis) on 2 sites in South Carolina, USA. We evaluated candidate models using information theoretic methods. Top scale-specific models included effects of conspecific density and number of cavity tree starts within 200 m of Red-cockaded Woodpecker foraging locations, and effects of the number of intraspecific interactions within 400 m of Red-cockaded Woodpecker foraging locations. The top multi-scale model for 22 of 34 Red-cockaded Woodpecker groups included covariates for the number of groups within 200 m of foraging locations and LiDARderived habitat with moderate densities of large pines (Pinus spp.) and minimal hardwood overstory. These results indicate distribution of neighboring groups was the most important predictor of space use once a minimal set of structural habitat thresholds was reached, and that placing recruitment clusters as little as 400 m from foraging partitions of neighboring groups may promote establishment of new breeding groups in unoccupied habitat. The presence of neighboring groups likely provides cues to foraging Red-cockaded Woodpeckers that facilitate prospecting prior to juvenile dispersal and, to a lesser extent, indicates high-quality forage resources. Careful consideration of local distribution of neighboring groups in potential habitat may improve managers’ ability to increase Red-cockaded Woodpecker density on restored landscapes and mitigate isolation of Red-cockaded Woodpecker groups, a problem that negatively affects fitness across the

  3. Range-Wide Meta-Analysis of Red-Cockaded Woodpecker Foraging Habitat Suitability

    Science.gov (United States)

    2013-12-31

    facilitate recovery and increase population sizes. The standard for managed stability, on the other hand, was not designed to increase population size, but to... designate these categories. Eglin AFB provided us with Eglin Model scores in the form of a geodatabase that covered the study site. Space use analysis...the niche gestalt of the red-cockaded woodpecker in longleaf pine forests. Ecological Applications 11:854-870. Koper, N., and M. Manseau. 2009

  4. The sunflower downy mildew pathogen Plasmopara halstedii.

    Science.gov (United States)

    Gascuel, Quentin; Martinez, Yves; Boniface, Marie-Claude; Vear, Felicity; Pichon, Magalie; Godiard, Laurence

    2015-02-01

    Downy mildew of sunflower is caused by Plasmopara halstedii (Farlow) Berlese & de Toni. Plasmopara halstedii is an obligate biotrophic oomycete pathogen that attacks annual Helianthus species and cultivated sunflower, Helianthus annuus. Depending on the sunflower developmental stage at which infection occurs, the characteristic symptoms range from young seedling death, plant dwarfing, leaf bleaching and sporulation to the production of infertile flowers. Downy mildew attacks can have a great economic impact on sunflower crops, and several Pl resistance genes are present in cultivars to protect them against the disease. Nevertheless, some of these resistances have been overcome by the occurrence of novel isolates of the pathogen showing increased virulence. A better characterization of P. halstedii infection and dissemination mechanisms, and the identification of the molecular basis of the interaction with sunflower, is a prerequisite to efficiently fight this pathogen. This review summarizes what is currently known about P. halstedii, provides new insights into its infection cycle on resistant and susceptible sunflower lines using scanning electron and light microscopy imaging, and sheds light on the pathogenicity factors of P. halstedii obtained from recent molecular data. Kingdom Stramenopila; Phylum Oomycota; Class Oomycetes; Order Peronosporales; Family Peronosporaceae; Genus Plasmopara; Species Plasmopara halstedii. Sunflower seedling damping off, dwarfing of the plant, bleaching of leaves, starting from veins, and visible white sporulation, initially on the lower side of cotyledons and leaves. Plasmopara halstedii infection may severely impact sunflower seed yield. In spring, germination of overwintered sexual oospores leads to sunflower root infection. Intercellular hyphae are responsible for systemic plant colonization and the induction of disease symptoms. Under humid and fresh conditions, dissemination structures are produced by the pathogen on all

  5. The upside of the emerald ash borer catastrophe: a feast for woodpeckers

    Science.gov (United States)

    David Cappaert; Deborah McCullough; Therese Poland

    2005-01-01

    Under the most favorable conditions, woodpeckers reduce larval EAB density as effectively as the best pesticides. Woodpeckers work over the entire core region for free and are always more popular than spray trucks.

  6. Density and abundance of black-backed woodpeckers in a Ponderosa pine ecosystem

    Science.gov (United States)

    Sean R. Mohren; Mark A. Rumble; Stanley H. Anderson

    2014-01-01

    Black-backed woodpeckers (Picoides arcticus) are usually associated with forest disturbance resulting in recently killed trees. While black-backed woodpeckers are attracted to areas affected by these disturbances, in the Black Hills they exist during interim disturbance periods in largely undisturbed forests. In 2012, a petition for listing black-backed woodpeckers in...

  7. AFLP studies on downy-mildew-resistant and downy-mildew-susceptible genotypes of opium poppy.

    Science.gov (United States)

    Dubey, Mukesh K; Shasany, Ajit K; Dhawan, Om P; Shukla, Ashutosh K; Khanuja, Suman P S

    2010-04-01

    Downy mildew (DM) caused by Peronospora arborescens, is a serious disease in opium poppy (Papaver somniferum), which has a world-wide spread. The establishment of DM-resistant cultivars appears to be a sustainable way to control the In this paper, we present the results of a study aimed at the identification of amplified fragment length polymorphism (AFLP) markers for DM-resistance in opium poppy. Three opium poppy genotypes (inbred over about 10 years): Pps-1 (DM-resistant), Jawahar-16 (DM-susceptible) and H-9 (DM-susceptible) were crossed in a diallel manner and the F(1) progeny along with the parents were subjected to AFLP analysis of chloroplast (cp) and nuclear DNA with seven and nine EcoRI / MseI primer combinations, respectively. cpDNA AFLP analysis identified 24 Pps-1 (DM-resistant)-specific unique fragments that were found to be maternally inherited in both the crosses, Pps-1 x Jawahar-16 and Pps-1 x H-9. In the case of nuclear DNA AFLP analysis, it was found that 17 fragments inherited from Pps-1 were common to the reciprocal crosses of both (i) Pps-1 and Jawahar-16 as well as (ii) Pps-1 and H-9. This is the first molecular investigation on the identification of polymorphism between DM-resistant and DM-susceptible opium poppy genotypes and development of DM-resistant opium poppy genotypespecific AFLP markers. These AFLP markers could be used in future genetic studies for analysis of linkage to the downy mildew resistance trait.

  8. Downy mildew: a serious disease threat to rose health worldwide

    Science.gov (United States)

    Peronospora sparsa is a downy mildew-causing oomycete that can infect roses, blackberries and other members of the rose family. During the last 20 years, this disease has become a serious problem for rose growers in the U.S. and worldwide. While much is known about the disease and its treatment, inc...

  9. Comparison of three fungicide spray advisories for lettuce downy mildew

    NARCIS (Netherlands)

    Wu, B.M.; Subbarao, K.V.; Bruggen, van A.H.C.; Koike, S.T.

    2001-01-01

    Lettuce growers in coastal California have relied mainly on protective fungicide sprays to control downy mildew. Thus, timing of sprays before infection is critical for optimal results. A leaf-wetness-driven, infection-based advisory system, previously developed, did not always perform

  10. Postharvest tillage reduces Downy Brome infestations in winter wheat

    Science.gov (United States)

    In the Pacific Northwest, downy brome continues to infest winter wheat producing regions especially in low-rainfall areas where the winter wheat-summer fallow rotation is the dominate production system. In Washington, a study was conducted for 2 years at each of two locations in the winter wheat -su...

  11. Multiple origins of downy mildews and mito-nuclear discordance within the paraphyletic genus Phytophthora

    Science.gov (United States)

    Choudhury, Robin A.; Mehl, Heather K.; Blomquist, Cheryl L.; McRoberts, Neil; Rizzo, David M.

    2018-01-01

    Phylogenetic relationships between thirteen species of downy mildew and 103 species of Phytophthora (plant-pathogenic oomycetes) were investigated with two nuclear and four mitochondrial loci, using several likelihood-based approaches. Three Phytophthora taxa and all downy mildew taxa were excluded from the previously recognized subgeneric clades of Phytophthora, though all were strongly supported within the paraphyletic genus. Downy mildews appear to be polyphyletic, with graminicolous downy mildews (GDM), brassicolous downy mildews (BDM) and downy mildews with colored conidia (DMCC) forming a clade with the previously unplaced Phytophthora taxon totara; downy mildews with pyriform haustoria (DMPH) were placed in their own clade with affinities to the obligate biotrophic P. cyperi. Results suggest the recognition of four additional clades within Phytophthora, but few relationships between clades could be resolved. Trees containing all twenty extant downy mildew genera were produced by adding partial coverage of seventeen additional downy mildew taxa; these trees supported the monophyly of the BDMs, DMCCs and DMPHs but suggested that the GDMs are paraphyletic in respect to the BDMs or polyphyletic. Incongruence between nuclear-only and mitochondrial-only trees suggests introgression may have occurred between several clades, particularly those containing biotrophs, questioning whether obligate biotrophic parasitism and other traits with polyphyletic distributions arose independently or were horizontally transferred. Phylogenetic approaches may be limited in their ability to resolve some of the complex relationships between the “subgeneric” clades of Phytophthora, which include twenty downy mildew genera and hundreds of species. PMID:29529094

  12. Current and Future Dynamics of the Red-Cockaded Woodpecker Population Inhabiting the Savannah River National Environmental Research Park: Managing For Population Growth

    International Nuclear Information System (INIS)

    Walters, J.R.; Taylor, T.B.; Daniels, S.J.; Crowder, L.B.; Pridd, J.A.

    2001-01-01

    Research aimed to study the dynamics of the SRS population of Red-Cockaded woodpecker and compare to those of other populations to identify factors limiting population growth; recruitment clusters were evaluated to determine what properties of individual cavity trees, surrounding habitat and the surrounding landscape might limit occupancy through natural dispersal. A spatial simulation model was used to project expected dispersal rates and population growth under current conditions and compare those estimates to observed dispersal and population growth. Red cockaded woodpecker populations at SRS are stable considering size. Research reveals that closer placement of recruitment clusters to active territories would produce higher growth rates while decreasing management intensity

  13. Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce

    Science.gov (United States)

    Simko, Ivan; Atallah, Amy J.; Ochoa, Oswaldo E.; Antonise, Rudie; Galeano, Carlos H.; Truco, Maria Jose; Michelmore, Richard W.

    2013-01-01

    Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in the 18th and 19th centuries, respectively, have high levels of quantitative resistance to downy mildew. We developed a population of recombinant inbred lines (RILs) originating from a cross between these two legacy cultivars, constructed a linkage map, and identified two QTLs for resistance on linkage groups 2 (qDM2.1) and 5 (qDM5.1) that determined resistance under field conditions in California and the Netherlands. The same QTLs determined delayed sporulation at the seedling stage in laboratory experiments. Alleles conferring elevated resistance at both QTLs originate from cultivar Iceberg. An additional QTL on linkage group 9 (qDM9.1) was detected through simultaneous analysis of all experiments with mixed-model approach. Alleles for elevated resistance at this locus originate from cultivar Grand Rapids. PMID:24096732

  14. Resistance Against Basil Downy Mildew in Ocimum Species.

    Science.gov (United States)

    Ben-Naim, Yariv; Falach, Lidan; Cohen, Yigal

    2015-06-01

    Downy mildew, caused by the oomycete Peronospora belbahrii, is a devastating disease of sweet basil. In this study, 113 accessions of Ocimum species (83 Plant Introduction entries and 30 commercial entries) were tested for resistance against downy mildew at the seedling stage in growth chambers, and during three seasons, in the field. Most entries belonging to O. basilicum were highly susceptible whereas most entries belonging to O. americanum, O. kilimanadascharicum, O. gratissimum, O. campechianum, or O. tenuiflorum were highly resistant at both the seedling stage and the field. Twenty-seven highly resistant individual plants were each crossed with the susceptible sweet basil 'Peri', and the F1 progeny plants were examined for disease resistance. The F1 plants of two crosses were highly resistant, F1 plants of 24 crosses were moderately resistant, and F1 plants of one cross were susceptible, suggesting full, partial, or no dominance of the resistance gene(s), respectively. These data confirm the feasibility of producing downy mildew-resistant cultivars of sweet basil by crossing with wild Ocimum species.

  15. Search efforts for ivory-billed woodpecker in South Carolina

    Science.gov (United States)

    Matthew Moskwik; Theresa Thom; Laurel M. Barnhill; Craig Watson; Jennifer Koches; John Kilgo; Bill Hulslander; Colette Degarady; Gary. Peters

    2013-01-01

    Following the reported rediscovery of Campephilus principalis (Ivory-billed Woodpecker) in Arkansas, we initiated searches in South Carolina in February 2006, with additional searches in the winter and spring of 2006–2007 and 2007–2008, concentrating in the Congaree, Santee, and Pee Dee river basins. We accrued a cumulative total of 8893 survey hours...

  16. Returning succession to downy brome dominated rangelands: roadblocks to perennial grass establishment

    Science.gov (United States)

    The most common cause of successional retrogression in the Great Basin is wildfires fueled by downy brome (Bromus tectorum). Downy brome invasion has reduced fire intervals from an estimated 60-100 years down to 5-10 years. Our previous research found that establishment of long-lived perennial grass...

  17. Rehabilitating downy brome (Bromus tectorum)-invaded scrublands using imazapic and seeding with native shrubs

    Science.gov (United States)

    Suzanne M. Owen; Carolyn Hull Sieg; Catherine A. Gehring

    2011-01-01

    Rehabilitation of downy brome-infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to...

  18. Identification of QTLs conferring resistance to downy mildew in legacy cultivars of lettuce

    Science.gov (United States)

    Many cultivars of lettuce (Lactuca sativa L.), the most popular leafy vegetable, are susceptible to downy mildew disease caused by Bremia lactucae. Cultivars Iceberg and Grand Rapids that were released in 18th and 19th century, respectively, have high levels of quantitative resistance to downy milde...

  19. The Conservation Value of Traditional Rural Landscapes: The Case of Woodpeckers in Transylvania, Romania.

    Directory of Open Access Journals (Sweden)

    Ine Dorresteijn

    Full Text Available Land use change is a major threat to global biodiversity. Forest species face the dual threats of deforestation and intensification of forest management. In regions where forests are under threat, rural landscapes that retain structural components of mature forests potentially provide valuable additional habitat for some forest species. Here, we illustrate the habitat value of traditional wood pastures for a woodpecker assemblage of six species in southern Transylvania, Romania. Wood pastures are created by long-term stable silvo-pastoral management practices, and are composed of open grassland with scattered large, old trees. Because of their demanding habitat requirements, woodpeckers share habitat with many other bird species, and have been considered as possible indicator species for bird species diversity. We first compared woodpecker assemblages between forests and wood pastures. Second, we grouped features of wood pastures into three spatial contexts and addressed how these features related to the occurrence of three woodpecker species that are formally protected. Woodpecker species composition, but not the number of species, differed between forests and wood pastures, with the green woodpecker occurring more commonly in wood pastures, and the lesser spotted woodpecker more commonly in forests. Within wood pastures, the intermediate context (especially surrounding forest cover best explained the presence of the grey-headed and middle spotted woodpecker. By contrast, variables describing local vegetation structure and characteristics of the surrounding landscape did not affect woodpecker occurrence in wood pastures. In contrast to many other parts of Europe, in which several species of woodpeckers have declined, the traditional rural landscape of Transylvania continues to provide habitat for several woodpecker species, both in forests and wood pastures. Given the apparent habitat value of wood pastures for woodpeckers we recommend wood

  20. The Conservation Value of Traditional Rural Landscapes: The Case of Woodpeckers in Transylvania, Romania

    Science.gov (United States)

    Dorresteijn, Ine; Hartel, Tibor; Hanspach, Jan; von Wehrden, Henrik; Fischer, Joern

    2013-01-01

    Land use change is a major threat to global biodiversity. Forest species face the dual threats of deforestation and intensification of forest management. In regions where forests are under threat, rural landscapes that retain structural components of mature forests potentially provide valuable additional habitat for some forest species. Here, we illustrate the habitat value of traditional wood pastures for a woodpecker assemblage of six species in southern Transylvania, Romania. Wood pastures are created by long-term stable silvo-pastoral management practices, and are composed of open grassland with scattered large, old trees. Because of their demanding habitat requirements, woodpeckers share habitat with many other bird species, and have been considered as possible indicator species for bird species diversity. We first compared woodpecker assemblages between forests and wood pastures. Second, we grouped features of wood pastures into three spatial contexts and addressed how these features related to the occurrence of three woodpecker species that are formally protected. Woodpecker species composition, but not the number of species, differed between forests and wood pastures, with the green woodpecker occurring more commonly in wood pastures, and the lesser spotted woodpecker more commonly in forests. Within wood pastures, the intermediate context (especially surrounding forest cover) best explained the presence of the grey-headed and middle spotted woodpecker. By contrast, variables describing local vegetation structure and characteristics of the surrounding landscape did not affect woodpecker occurrence in wood pastures. In contrast to many other parts of Europe, in which several species of woodpeckers have declined, the traditional rural landscape of Transylvania continues to provide habitat for several woodpecker species, both in forests and wood pastures. Given the apparent habitat value of wood pastures for woodpeckers we recommend wood pastures be explicitly

  1. When is an "Extinct" Species Really Extinct? Gauging the Search Efforts for Hawaiian Forest Birds and the Ivory-Billed Woodpecker

    Directory of Open Access Journals (Sweden)

    J. Michael. Scott

    2008-12-01

    Full Text Available Rare species, particularly those in inaccessible habitat, can go years without being observed. If we are to allocate conservation resources appropriately to conserving such species, it is important to be able to distinguish "rare" from "extinct." Criteria for designating extinction, however, tend to be arbitrary or vaguely defined. This designation should not be made unless the search effort has been sufficient to yield a high degree of confidence that the species is in fact absent. We develop models to assess the probability of extinction and the search effort necessary to detect an individual in a small population. We apply these models to searches for nine potentially extinct Hawaiian forest birds and for the Ivory-billed Woodpecker (Campephilus principalis in intensively searched areas in Arkansas. The Hawaiian forest bird survey was extensive, providing excellent information on population sizes and habitat associations of species encountered during the survey. Nonetheless, we conclude that the survey effort was not sufficient to conclude extinction (p > 0.90 for populations of 10 or fewer individuals for those species that were not encountered during surveys. In contrast, our analysis for Ivory-billed Woodpeckers suggests that, unless there were actually two or fewer birds present, the search effort was sufficient to conclude (p > 0.95 that Ivory-billed woodpeckers were not present in the intensively searched area. If one assumes distributions other than uniform, there is a greater chance that Ivory-billed Woodpeckers may persist in the intensively searched areas. Conclusions regarding occupancy of suitable habitat throughout the rest of the former range will require similarly intensive survey efforts. The degree of confidence in the absence of the Ivory-billed Woodpecker depended in part on our assumptions about the distribution of birds in the search area. For species with limited detection distance and small populations, a massive search

  2. Does red-cockaded woodpecker excavation of resin wells increase risk of bark beetle infestation of cavity trees?

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph; William G. Ross; David L. Kulhavy; Robert N. Coulson

    2001-01-01

    The red-cockaded woodpecker (Picoides borealis) is unique among North American woodpeckers in that it nests and roosts almost exclusively in living pines (Pinus spp.) The red-cockaded woodpecker makes daily excavations at small wounds, termed "resin wells," around the cavity entrance and on the bole of the cavity tree...

  3. Quantifying the impact of woodpecker predation on population dynamics of the emerald ash borer (Agrilus planipennis).

    Science.gov (United States)

    Jennings, David E; Gould, Juli R; Vandenberg, John D; Duan, Jian J; Shrewsbury, Paula M

    2013-01-01

    The emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle that has killed millions of ash trees (Fraxinus spp.) since it was accidentally introduced to North America in the 1990s. Understanding how predators such as woodpeckers (Picidae) affect the population dynamics of EAB should enable us to more effectively manage the spread of this beetle, and toward this end we combined two experimental approaches to elucidate the relative importance of woodpecker predation on EAB populations. First, we examined wild populations of EAB in ash trees in New York, with each tree having a section screened to exclude woodpeckers. Second, we established experimental cohorts of EAB in ash trees in Maryland, and the cohorts on half of these trees were caged to exclude woodpeckers. The following spring these trees were debarked and the fates of the EAB larvae were determined. We found that trees from which woodpeckers were excluded consistently had significantly lower levels of predation, and that woodpecker predation comprised a greater source of mortality at sites with a more established wild infestation of EAB. Additionally, there was a considerable difference between New York and Maryland in the effect that woodpecker predation had on EAB population growth, suggesting that predation alone may not be a substantial factor in controlling EAB. In our experimental cohorts we also observed that trees from which woodpeckers were excluded had a significantly higher level of parasitism. The lower level of parasitism on EAB larvae found when exposed to woodpeckers has implications for EAB biological control, suggesting that it might be prudent to exclude woodpeckers from trees when attempting to establish parasitoid populations. Future studies may include utilizing EAB larval cohorts with a range of densities to explore the functional response of woodpeckers.

  4. Detection probabilities of woodpecker nests in mixed conifer forests in Oregon

    Science.gov (United States)

    Robin E. Russell; Victoria A. Saab; Jay J. Rotella; Jonathan G. Dudley

    2009-01-01

    Accurate estimates of Black-backed (Picoides arcticus) and Hairy Woodpecker (P. villosus) nests and nest survival rates in post-fire landscapes provide land managers with information on the relative importance of burned forests to nesting woodpeckers. We conducted multiple-observer surveys in burned and unburned mixed coniferous forests in Oregon to identify important...

  5. Red-cockaded woodpecker cavity-tree damage by Hurricane Rita: an evaluation of contributing factors

    Science.gov (United States)

    Ben Bainbridge; Kristen A. Baum; Daniel Saenz; Cory K. Adams

    2011-01-01

    Picoides borealis (Red-cockaded Woodpecker) is an endangered species inhabiting pine savannas of the southeastern United States. Because the intensity of hurricanes striking the southeastern United States is likely to increase as global temperatures rise, it is important to identify factors contributing to hurricane damage to Red-cockaded Woodpecker cavity-trees. Our...

  6. Evidence Suggesting that Ivory-billed Woodpeckers (Campephilus principalis Exist in Florida

    Directory of Open Access Journals (Sweden)

    Daniel J. Mennill

    2006-12-01

    Full Text Available The Ivory-billed Woodpecker (Campephilus principalis disappeared from the forests of southeastern North America in the early 20th Century and for more than 50 years has been widely considered extinct. On 21 May 2005, we detected a bird that we identified as an Ivory-billed Woodpecker in the mature swamp forest along the Choctawhatchee River in the panhandle of Florida. During a subsequent year of research, members of our small search team observed birds that we identified as Ivory-billed Woodpeckers on 14 occasions. We heard sounds that matched descriptions of Ivory-billed Woodpecker acoustic signals on 41 occasions. We recorded 99 putative double knocks and 210 putative kent calls. We located cavities in the size range reported for Ivory-billed Woodpeckers and larger than those of Pileated Woodpeckers (Dryocopus pileatus that have been reported in the literature or that we measured in Alabama. We documented unique foraging signs consistent with the feeding behavior of Ivory-billed Woodpeckers. Our evidence suggests that Ivory-billed Woodpeckers may be present in the forests along the Choctawhatchee River and warrants an expanded search of this bottomland forest habitat.

  7. Red-cockaded woodpecker nutritional status in relation to habitat: Evidence from ptilochronology and body mass

    Science.gov (United States)

    Richard R. Schaefer; D. Craig Rudolph; Richard N. Conner; Daniel Saenz

    2004-01-01

    Sexual divergence in foraging behavior exhibited by red-cockaded woodpeckers (Picoides borealis) should reduce intersexual competition for foraging sites. Males tend to forage at greater heights and on smaller stem diameters than females. It is well known that red-cockaded woodpeckers have an aversion to a well-developed stratum of midstory...

  8. Heart rot hotel: fungal communities in red-cockaded woodpecker excavations

    Science.gov (United States)

    Michelle A. Jusino; Daniel L. Lindner; Mark T. Banik; Jeffrey R. Walters

    2015-01-01

    Tree-cavity excavators such as woodpeckers are ecosystem engineers that have potentially complex but poorly documented associations with wood decay fungi. Fungi facilitate cavity excavation by preparing and modifying excavation sites for cavity excavators. Associations between fungi and endangered red-cockaded woodpeckers (RCWs) are particularly interesting because...

  9. Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels.

    Energy Technology Data Exchange (ETDEWEB)

    Loeb, Susan C; Ruth, Deanna L

    2004-12-31

    Loeb, Susan C., and Deanna L. Ruth. 2004. Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 8. Cavities, Cavity Trees, and Cavity Communities. Pp 501-502. Abstract: Southern flying squirrels can significantly impact red-cockaded woodpecker reproductive success (Laves and Loeb 1999). Thus exclusion or removal of flying squirrels from red-cockaded woodpecker cavities and clusters may be warranted in small woodpecker populations (U.S. Fish and Wildlife Service 2003). However, development of effective and efficient protocols for southern flying squirrel control requires an understanding of the seasonal dynamics of southern flying squirrel cavity use. Most studies of southern flying squirrel use of red-cockaded woodpecker cavities have been conducted during spring (e.g., Harlow and Lennartz 1983, Rudolph et al. 1990a, Loeb 1993) and no studies have examined the effects of long term flying squirrel control on subsequent cavity use. The objectives of this study were to determine: (1) whether flying squirrel use of red-cockaded woodpecker cavities varies with season or cavity type, and (2) the long term effect of continuous squirrel removal.

  10. Drill, baby, drill: the influence of woodpeckers on post-fire vertebrate communities through cavity excavation

    Science.gov (United States)

    Gina L. Tarbill; Patricia N. Manley; Angela M. White

    2015-01-01

    Several studies have addressed the importance of woodpeckers as ecological engineers in forests due to their excavation of cavities. Although research in green, unburned forests has identified the influence of different excavators on secondary use by cavity-dependent species, little is known about the relative importance of cavities created by woodpeckers in recently...

  11. Red-Cockaded Woodpecker male/female foraging differences in young forest stands

    Science.gov (United States)

    Kathleen E. Franzreb

    2010-01-01

    The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinusspp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in...

  12. Foraging-habitat selection of Black-backed Woodpeckers in forest burns of southwestern Idaho

    Science.gov (United States)

    Jonathan G. Dudley; Victoria A. Saab; Jeffrey P. Hollenbeck

    2012-01-01

    We examined foraging-habitat selection of Black-backed Woodpeckers (Picoides arcticus) in burned forests of southwestern Idaho during 2000 and 2002 (6 and 8 years following wildfire). This woodpecker responds positively to large-scale fire disturbances and may be at risk from logging and post-fire management. With 100 radio-locations of four adult males, we used...

  13. Habitat use and avoidance by foraging red-cockaded woodpeckers in east Texas

    Science.gov (United States)

    John N. Macey; D. Brent Burt; Daniel Saenz; Richard N. Conner

    2016-01-01

    Picoides borealis (Red-cockaded Woodpecker) is an endangered bird endemic to the Pinus (pine) ecosystems of the southeastern US. Mature pine savannahs with a minimal midstory and lush herbaceous groundcover represent high-quality habitat. This study examines the foraging-habitat patterns of Red-cockaded Woodpeckers in East...

  14. Woodpecker-inspired shock isolation by microgranular bed

    International Nuclear Information System (INIS)

    Yoon, Sang-Hee; Roh, Jin-Eep; Kim, Ki Lyug

    2009-01-01

    This paper presents a woodpecker-inspired shock isolation (SI) using a microgranular bed to protect micromachined electronic devices (MEDs) for high-g military applications where mechanical excitations reach up to tens of thousands of gs and several hundreds of kHz. The shock isolating phenomenon in the microgranular bed within a metal housing, biomimetically inspired from a spongy bone within a skull of the woodpecker, controls unwanted high-frequency mechanical excitations so that their adverse effects on the embedded MEDs are kept within acceptable limit. The microgranular bed composed of close-packed microglass beads reduces the mechanical excitations transmitted to the MEDs through kinetic energy absorption. Two kinds of tests, a laboratory test and a 60 mm air-gun test, have been made. The laboratory test using a vibration exciter up to 25 kHz has demonstrated that the cut-off frequency (2.2-15.8 kHz) and roll-off steepness (-155.0 to -78.7 dB decade -1 ) are inversely proportional to the diameter of the close-packed microglass beads (68-875 μm), whereas the vibration absorptivity (0.23-0.87) is proportional. The 60 mm air-gun test under high-g environments of up to 60 000 g has verified that the woodpecker-inspired SI is superior in improving the shock survivability of the MEDs to the conventional one using hard resin.

  15. Habitat preferences of foraging red-cockaded woodpeckers at the Savannah River Site, South Carolina.

    Energy Technology Data Exchange (ETDEWEB)

    Franzreb, Kathleen, E.

    2004-12-31

    Franzreb, Kathleen, E. 2004. Habitat preferences of foraging red-cockaded woodpeckers at the Savannah River Site, South Carolina. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 9. Habitat Management and Habitat Relationships. Pp 553-561. Abstract: I constructed a foraging study to examine habitat use of red-cockaded woodpeckers at the Savannah River Site, South Carolina. Because much of the land had been harvested in the late 1940s and early 1950s prior to being sold to the Department of Energy, the available habitat largely consisted of younger trees (e.g., less than 40 years old). From 1992 to 1995, I examined the foraging behavior and reproductive success of 7 groups of red-cockaded woodpeckers.

  16. Two species of Gelechioidea (Lepidoptera) from Southeast Asia associated with downy rose myrtle, Rhodomyrtus tomentosa (Myrtaceae)

    Science.gov (United States)

    Two species of Gelechioidea (Lepidoptera), Metharmostis multilineata Adamski, n. sp. (Cosmopterigidae), and Idiophantis soreuta Meyrick, 1906 (Gelechiidae), were collected in southeastern Asia for evaluation as potential biocontrol agents against downy rose myrtle, Rhodomyrtus tomentosa (Aiton) Hass...

  17. Assessment of Downy mildew Resistance (Peronospora farinosa) in a Quinoa (Chenopodium quinoa Willd.) Germplasm

    OpenAIRE

    Manal Mhada; BrahimEzzahiri; Ouafae Benlhabib

    2014-01-01

    Seventy-nine accessions, including two local wild species (Chenopodium album and C. murale) and several cultivated quinoa lines developed through recurrent selection in Morocco were screened for their resistance against Peronospora farinose, the causal agent of downy mildew disease. The method of artificial inoculation on detached healthy leaves taken from the middle stage of the plant was used. Screened accessions showed different levels of quantitative resistance to downy mildew as they wer...

  18. A first linkage map and downy mildew resistance QTL discovery for sweet basil (Ocimum basilicum) facilitated by double digestion restriction site associated DNA sequencing (ddRADseq).

    Science.gov (United States)

    Pyne, Robert; Honig, Josh; Vaiciunas, Jennifer; Koroch, Adolfina; Wyenandt, Christian; Bonos, Stacy; Simon, James

    2017-01-01

    Limited understanding of sweet basil (Ocimum basilicum L.) genetics and genome structure has reduced efficiency of breeding strategies. This is evidenced by the rapid, worldwide dissemination of basil downy mildew (Peronospora belbahrii) in the absence of resistant cultivars. In an effort to improve available genetic resources, expressed sequence tag simple sequence repeat (EST-SSR) and single nucleotide polymorphism (SNP) markers were developed and used to genotype the MRI x SB22 F2 mapping population, which segregates for response to downy mildew. SNP markers were generated from genomic sequences derived from double digestion restriction site associated DNA sequencing (ddRADseq). Disomic segregation was observed in both SNP and EST-SSR markers providing evidence of an O. basilicum allotetraploid genome structure and allowing for subsequent analysis of the mapping population as a diploid intercross. A dense linkage map was constructed using 42 EST-SSR and 1,847 SNP markers spanning 3,030.9 cM. Multiple quantitative trait loci (QTL) model (MQM) analysis identified three QTL that explained 37-55% of phenotypic variance associated with downy mildew response across three environments. A single major QTL, dm11.1 explained 21-28% of phenotypic variance and demonstrated dominant gene action. Two minor QTL dm9.1 and dm14.1 explained 5-16% and 4-18% of phenotypic variance, respectively. Evidence is provided for an additive effect between the two minor QTL and the major QTL dm11.1 increasing downy mildew susceptibility. Results indicate that ddRADseq-facilitated SNP and SSR marker genotyping is an effective approach for mapping the sweet basil genome.

  19. Allelopathic effects of leaf and corm water extract of saffron (Crocus sativus L. on germination and seedling growth of flixweed (Descurainia sophia L. and downy brome (Bromus tectorum L.

    Directory of Open Access Journals (Sweden)

    Zeinab Alipoor

    2015-04-01

    Full Text Available This study was conducted in two factorial experiment based on completely randomized design with three replications at research laboratory of faculty of agriculture in University of Birjand in 2013. Factors included saffron organs at 2 levels (leaves and corms and water extract concentrations at 5 levels (0, 0.5, 1, 1.5 and 2 percent.The allelopathic effects of saffron leaves and corms on seed germination and seedling growth characteristics of flixweed (Descurainia sophia L. and downy brome (Bromus tectorum L. were studied in two separate experiments. Results indicated lowest seed germination percentage of downy brome and flixweed were observed at concentration of 2% of corm extract (by 65% and 66% reduce compared to control, respectively. The rate of germination of downy brome decreased (by 71% compared to control with concentration of 2% of leaf extract but the rate of germination on flixweed was not significantly affected by extract concentrations. Different concentrations of leaf and corm extracts significantly decreased length and weight of plumule and radicals of two weeds. A logistic model provided a successful estimation of relationship between leaf water extract and germination percentage of two weeds. Based on orthogonal comparison tests, the allelopathic inhibition effects of saffron leaves and corms were more on downy brome and flixweed, respectively.

  20. Diet of Nesting Red-Cockaded Woodpecker at Three Locations

    Energy Technology Data Exchange (ETDEWEB)

    Hanula, J.L.; Lipcomb, D.; Franzreb, K.E.; Loeb, S.C.

    1998-12-03

    The authors studied diets of nestling red-cockaded woodpeckers for two years on three sites in South Carolina and Georgia. Cameras recorded 33 different types of prey. Wood roaches were the most common, amounting to 50% of the prey. In addition, blueberries and saw fly larvae were collected by birds. Snail shells were also collected. Morista's index of diet overlap ranged from 0.94 to 0.99 for breeding males and females. We conclude that nestling diets are similar across the region.

  1. Availability and abundance of prey for the red-cockaded woodpecker.

    Energy Technology Data Exchange (ETDEWEB)

    Hanula, James, L.; Horn, Scott

    2004-12-31

    Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 11. Prey, Fire, and Community Ecology. Pp 633-645. Abstract: Over a 10-year period we investigated red-cockaded woodpecker (Picoides borealis) prey use, sources of prey, prey distribution within trees and stands, and how forest management decisions affect prey abundance in South Carolina, Alabama, Georgia and Florida. Cameras were operated at 31 nest cavities to record nest visits with prey in 4 locations that ranged in foraging habitat from pine stands established in old fields to an old-growth stand in South Georgia. Examination of nearly 12,000 photographs recorded over 5 years revealed that, although red-cockaded woodpeckers used over 40 arthropods for food, the majority of the nestling diet is comprised of a relatively small number of common arthropods.

  2. Assessment of Training Noise Impacts on the Red-Cockaded Woodpecker: 1999 Results

    National Research Council Canada - National Science Library

    Delaney, David

    2000-01-01

    .... Increased importance has been placed on determining how noise affects these species. This report presents second year results of a multiyear study to determine the effects of certain kinds of training noise on the endangered Red-cockaded Woodpecker...

  3. The effect of using a "soft" release on translocation success of red-cockaded woodpeckers.

    Energy Technology Data Exchange (ETDEWEB)

    Franzreb, Kathleen, E.

    2004-12-31

    Franzreb, Kathleen, E. 2004 The effect of using a "soft" release on translocation success of red-cockaded woodpeckers. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 6. Translocation. Pp 301-306. Abstract: Translocations of the endangered red-cockaded woodpecker have been conducted since 1986 to enhance critically small subpopulations, to minimize the likelihood of local extirpations, and to reduce the adverse effects of fragmentation and isolation among existing populations. Such attempts have had mixed success. This article compares "hard" releases with a "soft" release technique where the birds are temporarily interned in a large aviary at the release point for a period of 9 to 14 days.

  4. Effects of soil amendments on germination and emergence of downy brome (Bromus tectorum) and Hilaria jamesii

    Science.gov (United States)

    Belnap, J.; Sherrod, S.K.; Miller, M.E.

    2003-01-01

    Downy brome is an introduced Mediterranean annual grass that now dominates millions of hectares of western U.S. rangelands. The presence of this grass has eliminated many native species and accelerated wildfire cycles. The objective of this study was to identify soil additives that allowed germination but inhibited emergence of downy brome, while not affecting germination or emergence of the native perennial grass Hilaria jamesii. On the basis of data from previous studies, we focused on additives that altered the availability of soil nitrogen (N), phosphorus (P), and potassium (K). Most water-soluble treatments inhibited downy brome germination and emergence. We attribute the inhibitory effects of these treatments to excessive salinity and ion-specific effects of the additives themselves. An exception to this was oxalic acid, which showed no effect. Most water-insoluble treatments had no effect in soils with high P but did have an effect in soils with low P. Zeolite was effective regardless of P level, probably due to the high amounts of Na+ it added to the soil solution. Most treatments at higher concentrations resulted in lower downy brome emergence rates in soils currently dominated by downy brome than in uninvaded (but theoretically invadable) Hilaria soils. This difference is possibly attributable to inherent differences in labile soil P. In Stipa soils, where Stipa spp. grow, but which are generally considered to be uninvadable by downy brome, additions of high amounts of N resulted in lower emergence. This may have been an effect of NH4 + interference with uptake of K or other cations or toxicity of high N. We also saw a positive relationship between downy brome emergence and pH in Stipa soils. Hilaria development parameters were not as susceptible to the treatments, regardless of concentration, as downy brome. Our results suggest that there are additions that may be effective management tools for inhibiting downy brome in calcareous soils, including (1

  5. The response of adult red-cockaded woodpeckers to a fallen nestling

    Science.gov (United States)

    Richard R. Schaefer; D. Craig Rudolph; Richard N. Conner

    1991-01-01

    The response of adult Red-cockaded Woodpeckers to a fallen nestling- On 31 May 1990, while watching a pair of Red-cockaded Woodpeckers (Picoides borealis) feeding two 20- day-old nestlings, we observed the following behavior. At 6:30 DST, the adult male flew to the entrance of the nest cavity with prey. He did not immediately offer the prey to the...

  6. Intra-annual variation in habitat choice by an endemic woodpecker: Implications for forest management and conservation

    Science.gov (United States)

    Garcia-del-Rey, Eduardo; Fernández-Palacios, José María; Muñoz, Pascual Gil

    2009-09-01

    The Canary Islands great spotted woodpecker Dendrocopos major canariensis is an endemic bird restricted to the Pinus canariensis forests of Tenerife and Gran Canaria. Classification tree models were applied to explore the relationship of the occurrence of this picid and habitat variables between two contrasting periods (breeding vs. non-breeding seasons) and for the entire annual cycle. During the reproductive period the availability of mature trees (DBH > 60 cm), and snags (dead trees), for nesting and roosting, characterize the breeding territory. Outside the breeding season the choice of locations was driven by a tree cover larger than 28.5% and the presence of trees taller than 8.5 m on average, a pattern explained by the availability of pine seeds in the cones of well-developed canopies, and less so by predation risk. Overall, during the annual cycle, well-developed canopy sites influenced the presence of this picidae (tree cover > 38%) and on more open sites ( 60 cm) became the second most important predictor of occurrence. We suggest that food abundance and availability could be the ultimate factor explaining the intra-annual variation observed, with the availability of snags being an important factor during nesting. In the range of this endemic, we recommend selective cuts in pine plantations, to allow the trees to set seed and improve their crops, minimizing the elimination of snags, and killing some large pine trees if the priority is to expand the distributional range of the woodpecker.

  7. Plasmopara viticola: a review of knowledge on downy mildew of grapevine and effective disease management

    Directory of Open Access Journals (Sweden)

    Cesare GESSLER

    2011-05-01

    Full Text Available Normal 0 14 false false false IT ZH-TW X-NONE MicrosoftInternetExplorer4 The oomycete Plasmopara viticola is native to North America and was accidentally introduced into Europe at the end of the 19th century, where it caused widespread damage to the grape industry. Since that time, the damage caused by this plant pathogen has generally been controlled with multiple fungicide applications. Modern fungicides applied as prescribed by weather-based warning systems can effectively prevent any damage that might be caused. Alternatives to chemical treatments, such as the use of biocontrol agents or resistant cultivars, currently play a marginal role in controlling this disease. Until the middle of last century, research efforts were mainly concentrated on optimizing the application of copper fungicides and developing new molecules and formulations for controlling the disease. During the second half of the last century, highly efficient products for control were available, so research efforts moved toward optimizing and minimizing chemical control, mostly through the use of weather-based warning systems based on complex biological models. In the last 20 years, parallel to the development of technologies for genomic and transcriptomic analyses, host-pathogen interactions and population genetics have captured the interest of researchers in this field. Breeding for resistance against downy mildew has always coexisted with chemical control. However, the results of these breeding programmes have traditionally been cultivated only in marginal areas and organic production systems. This review traces the history of European knowledge of P. viticola.

  8. Injection of 2,4-D to remove hardwood midstory within red-cockaded woodpecker colony areas

    Science.gov (United States)

    Richard N. Conner

    1989-01-01

    Red-cockaded woodpecker (Picoides borealis) colonies on the Angelina National Forest were monitored from 1984 to 1986, after hardwoods on the site had been injected with the herbicide 2,4-D. The herbicide effectively reduced the hardwood midstory; however, possible toxicity to woodpeckers and cavity tree mortality are problems associated with the...

  9. Heterothallism in Peronospora farinosa f.sp. chenopodii, the causal agent of downy mildew of quinoa (Chenopodium quinoa).

    Science.gov (United States)

    Danielsen, S

    2001-01-01

    Heterothallism in Peronospora farinosa f.sp. chenopodii, the causal agent of downy mildew of quinoa (Chenopodium quinoa) is reported for the first time. Downy mildew is the most important disease of this crop in the Andean region. Eight single-lesion isolates from different regions in Peru and Bolivia were crossed in all possible combinations using a detached leaf assay, to determine the mating system of the downy mildew pathogen. The presence of two mating types, P1 and P2, was revealed showing that P. farinosa f.sp. chenopodii is heterothallic. It is suggested that frequent sexual reproduction is an important evolutionary force in this pathogen in South America.

  10. Downy mildew on coleus (Plectranthus scutellarioides) caused by Peronospora belbahrii sensu lato in Tennessee

    Science.gov (United States)

    Coleus (Plectranthus scutellarioides [syn. = Solenostemon scutellarioides]) is a popular ornamental plant in the mint family (Lamiaceae), prized for its colorful and showy foliage. In August 2015, disease symptoms typical of downy mildew were observed at two sites in Nashville, Tennessee: (i) at the...

  11. a survey of sorghum downy mildew in sorghum in the sudano

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. An extensive survey was conducted across the 13 states constituting the Sudan and Sahel savanna agro-ecological zones of Nigeria to determine the occurrence and distribution of sorghum downy mildew in sorghum during the 2008 growing season. The survey was conducted at two different stages of the ...

  12. Effect of detergent on the quantification of grapevine downy mildew Sporangia from leaf discs

    Science.gov (United States)

    Grapevine downy mildew (DM), caused by the oomycete Plasmopara viticola (Berk. & Curt.) Berlese & de Toni, is a major disease, especially in humid viticultural areas. Development of resistant cultivars is an important objective for grapevine breeding. In order to establish a reliable and inexpensive...

  13. Is Pyrenophora semeniperda the cause of downy brome (Bromus tectorum) die-offs?

    Science.gov (United States)

    Owen W. Baughman; Susan E. Meyer

    2013-01-01

    Downy brome (cheatgrass) is a highly successful, exotic, winter annual invader in semi-arid western North America, forming near-monocultures across many landscapes. A frequent but poorly understood phenomenon in these heavily invaded areas is periodic 'die-off' or complete stand failure. The fungal pathogen Pyrenophora semeniperda is abundant in cheatgrass...

  14. The ghost of outcrossing past in downy brome, an inbreeding annual grass

    Science.gov (United States)

    Susan E. Meyer; Sudeep Ghimire; Samuel Decker; Keith R. Merrill; Craig E. Coleman

    2013-01-01

    We investigated the frequency of outcrossing in downy brome (Bromus tectorum L.), a cleistogamous weedy annual grass, in both common garden and wild populations, using microsatellite and single nucleotide polymorphic (SNP) markers. In the common garden study, 25 lines with strongly contrasting genotypes were planted in close proximity. We fingerprinted 10 seed progeny...

  15. Post-fire Downy Brome (Bromus tectorum) invasion at high elevation in Wyoming

    Science.gov (United States)

    The invasive annual grass downy brome is the most ubiquitous weed in sagebrush systems of western North America. The center of invasion has largely been the Great Basin region, but there is an increasing abundance and distribution in the Rocky Mountain States. We evaluated post-fire vegetation chang...

  16. Soil engineering facilitates Downy brome (Bromus tectorum L.) growth - A case study

    Science.gov (United States)

    Some exotic plants are able to engineer new host soils and engender characteristics that potentially increase their growth. We hypothesized that this positive feedback may be a facet in the competitiveness of the exotic annual grass downy brome. Using rhizotrons in the greenhouse, we compared the gr...

  17. A survey of sorghum downy mildew in sorghum in the Sudano ...

    African Journals Online (AJOL)

    An extensive survey was conducted across the 13 states constituting the Sudan and Sahel savanna agro-ecological zones of Nigeria to determine the occurrence and distribution of sorghum downy mildew in sorghum during the 2008 growing season. The survey was conducted at two different stages of the crop ...

  18. Effector identification in the lettuce downy mildew Bremia lactucae by massively parallel transcriptome sequencing

    NARCIS (Netherlands)

    Stassen, J.H.; Seidl, M.F.; Vergeer, P.W.; Nijman, I.J.; Snel, B.; Cuppen, E.; van den Ackerveken, G.

    2012-01-01

    Lettuce downy mildew (Bremia lactucae) is a rapidly adapting oomycete pathogen affecting commercial lettuce cultivation. Oomycetes are known to use a diverse arsenal of secreted proteins (effectors) to manipulate their hosts. Two classes of effector are known to be translocated by the host: the

  19. Assessing the vulnerability of sorghum converted lines to anthracnose and downy mildew infection

    Science.gov (United States)

    A total of 59 converted sorghum lines and six checks were evaluated for resistance to two foliar fungal diseases, anthracnose and downy mildew (SDM) in 2008 and 2009 growing seasons at the Texas A&M AgriLife Research Farm, College Station, Texas. In 2008, 23 lines exhibited resistance (35%), 29 sus...

  20. Advances in diagnostics of downy mildews: Lessons learned from other oomycetes and future challenges

    Science.gov (United States)

    Early detection of downy mildews in the environment is critical to establish pathogen presence and identity, determine fungicide resistance, and understand how pathogen populations disperse. Knowing when and where pathogens emerge is also important for identifying critical control points to restrict...

  1. Basil Downy Mildew (Peronospora belbahrii): Discoveries and Challenges Relative to Its Control.

    Science.gov (United States)

    Wyenandt, Christian A; Simon, James E; Pyne, Robert M; Homa, Kathryn; McGrath, Margaret T; Zhang, Shouan; Raid, Richard N; Ma, Li-Jun; Wick, Robert; Guo, Li; Madeiras, Angela

    2015-07-01

    Basil (Ocimum spp.) is one of the most economically important and widely grown herbs in the world. Basil downy mildew, caused by Peronospora belbahrii, has become an important disease in sweet basil (O. basilicum) production worldwide in the past decade. Global sweet basil production is at significant risk to basil downy mildew because of the lack of genetic resistance and the ability of the pathogen to be distributed on infested seed. Controlling the disease is challenging and consequently many crops have been lost. In the past few years, plant breeding efforts have been made to identify germplasm that can be used to introduce downy mildew resistance genes into commercial sweet basils while ensuring that resistant plants have the correct phenotype, aroma, and tastes needed for market acceptability. Fungicide efficacy studies have been conducted to evaluate current and newly developed conventional and organic fungicides for its management with limited success. This review explores the current efforts and progress being made in understanding basil downy mildew and its control.

  2. Process-based management approaches for salt desert shrublands dominated by downy brome

    Science.gov (United States)

    Downy brome grass (Bromus tectorum L.) invasion has severely altered key ecological processes such as disturbance regimes, soil nutrient cycling, community assembly, and successional pathways in semi-arid Great Basin salt desert shrublands. Restoring the structure and function of these severly alte...

  3. Effector identification in the lettuce downy mildew Bremia lactucae by massively parallel transcriptome sequencing.

    Science.gov (United States)

    Stassen, Joost H M; Seidl, Michael F; Vergeer, Pim W J; Nijman, Isaäc J; Snel, Berend; Cuppen, Edwin; Van den Ackerveken, Guido

    2012-09-01

    Lettuce downy mildew (Bremia lactucae) is a rapidly adapting oomycete pathogen affecting commercial lettuce cultivation. Oomycetes are known to use a diverse arsenal of secreted proteins (effectors) to manipulate their hosts. Two classes of effector are known to be translocated by the host: the RXLRs and Crinklers. To gain insight into the repertoire of effectors used by B. lactucae to manipulate its host, we performed massively parallel sequencing of cDNA derived from B. lactucae spores and infected lettuce (Lactuca sativa) seedlings. From over 2.3 million 454 GS FLX reads, 59 618 contigs were assembled representing both plant and pathogen transcripts. Of these, 19 663 contigs were determined to be of B. lactucae origin as they matched pathogen genome sequences (SOLiD) that were obtained from >270 million reads of spore-derived genomic DNA. After correction of cDNA sequencing errors with SOLiD data, translation into protein models and filtering, 16 372 protein models remained, 1023 of which were predicted to be secreted. This secretome included elicitins, necrosis and ethylene-inducing peptide 1-like proteins, glucanase inhibitors and lectins, and was enriched in cysteine-rich proteins. Candidate host-translocated effectors included 78 protein models with RXLR effector features. In addition, we found indications for an unknown number of Crinkler-like sequences. Similarity clustering of secreted proteins revealed additional effector candidates. We provide a first look at the transcriptome of B. lactucae and its encoded effector arsenal. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

  4. Rediscovering the King of Woodpeckers: Exploring the Implications

    Directory of Open Access Journals (Sweden)

    Jeffrey R. Walters

    2005-12-01

    Full Text Available The Ivory-billed Woodpecker has long held a special place in the psyche of North American conservation, eliciting unusually colorful prose, even from scientists, as an icon of the wild. The reverence in which it was held did little to slow the habitat loss that led to its apparent extinction 60 years ago. A consequence of the emotion and attention associated with the amazing rediscovery of this species is that conservation biologists will be under considerable pressure to make good on this "second chance." This poses a challenge to conservation paradigms that has important political consequences. First, the decline of the species is due to habitat loss, recovery from which has been much more seldom achieved than recovery from declines due to impacts on vital rates. This challenge is exacerbated by the enormous area requirements of the species. Second, the species at best exists as a critically small population. It will be difficult to make the case that a viable population can be established without undermining the small population paradigm that underlies conservation strategies for many other species. This has already resulted in some political backlash. Conservation of this species is best based on the one point of clear scientific consensus, that habitat is limiting, but this may result in additional political backlash because of conflicts with other land uses.

  5. Occurrence patterns of Black-backed Woodpeckers in green forest of the Sierra Nevada Mountains, California, USA.

    Directory of Open Access Journals (Sweden)

    Alissa M. Fogg

    2014-12-01

    Full Text Available Black-backed Woodpeckers (Picoides arcticus are a rare habitat specialist typically found in moderate and high severity burned forest throughout its range. It also inhabits green forest but little is known about occurrence and habitat use patterns outside of burned areas, especially in the Sierra Nevada of California, USA. We used point count and playback surveys to detect Black-backed Woodpeckers during 2011 - 2013 on 460 transects on 10 national forest units. We defined green forest as areas that had not burned at moderate or high severity since 1991 and were more than 2 km from areas burned at moderate or high severity within the previous eight years (n = 386 transects. We used occupancy models to examine green forest habitat associations and found positive relationships with elevation, latitude, northern aspects, number of snags, tree diameter, lodgepole pine (Pinus contorta forest, and a negative relationship with slope. Estimated occupancy in green forest was higher than previously understood (0.21. In addition site colonization and extinction probability in green forest were low (0.05 and 0.19, respectively and suggest that many of the individuals detected in green forest were not just actively dispersing across the landscape in search of burned areas, but were occupying relatively stable home ranges. The association with high elevation and lodgepole pine forest may increase their exposure to climate change as these elevation forest types are predicted to decrease in extent over the next century. Although density is high in burned forest, green forest covers significantly more area in the Sierra Nevada and should be considered in efforts to conserve this rare species.

  6. Nest-site selection and nest survival of Lewis's woodpecker in aspen riparian woodlands

    Science.gov (United States)

    Karen R. Newlon; Victoria A. Saab

    2011-01-01

    Riparian woodlands of aspen (Populus tremuloides) provide valuable breeding habitat for several cavity-nesting birds. Although anecdotal information for this habitat is available for Lewis's Woodpecker (Melanerpes lewis), no study has previously examined the importance of aspen woodlands to this species' breeding biology. From 2002 to 2004, we monitored 76...

  7. Texas ratsnake predation on southern flying squirrels in red-cockaded woodpecker cavities

    Science.gov (United States)

    D. Craig Rudolph; Richard R. Schaefer; Josh B. Pierce; Dan Saenz; Richard N. Conner

    2009-01-01

    Elaphe spp. (ratsnakes) are frequent predators on cavity-nesting birds and other vertebrates, including Glaucomys volans (Southern Flying Squirrels). They are known predators of Picoides borealis (Red-cockaded Woodpeckers), especially during the nestling phase. Picoides borealis cavities are frequently occupied by Southern Flying Squirrels, often several squirrels per...

  8. Experimental evidence of a symbiosis between red-cockaded woodpeckers and fungi

    Science.gov (United States)

    Michelle A. Jusino; Daniel L. Lindner; Mark T. Banik; Kevin R. Rose; Jeffrey R. Walters

    2016-01-01

    Primary cavity excavators, such as woodpeckers, are ecosystem engineers in many systems. Associations between cavity excavators and fungi have long been hypothesized to facilitate cavity excavation, but these relationships have not been experimentally verified. Fungi may help excavators by softening wood, while excavators may facilitate fungal dispersal. Here we...

  9. Consumption of Mullerian Bodies by Golden-olive Woodpecker (Colaptes rubiginosus) in Nicaragua's Highlands

    Science.gov (United States)

    M.A. Torrez; Wayne Arendt; L. Diaz

    2016-01-01

    The Golden-olive Woodpecker is a generalist species found in a wide range of habitats, being particularly common in coffee plantations within Nicaraguan cloud forests. Observations of an individual feeding at the base of Cecropia leaves revealed it was consuming Mullerian bodies that the Cecropia produces to feed Azteca ants as part of a host-inhabitant mutualistic...

  10. Monitoring interactions between red-cockaded woodpeckers and southern flying squirrels

    Science.gov (United States)

    Thomas S. Risch; Susan C. Loeb

    2004-01-01

    Although several studies have suggested that southern flying squirrels (Glaucomys volans) may have a signif- icant negative impact on red-cockaded woodpeckers (Picoides borealis) (Loeb and Hooper 1997, Laves and Loeb 1999), the nature of the interactions between the species remains unclear. Particularly lacking are data that address if southern flying squirrels...

  11. Acorns and acorn woodpeckers: ups and downs in a long-term relationship

    Science.gov (United States)

    Walter D. Koenig; Eric L. Walters; Johannes M.H. Knops; William J. Carmen

    2015-01-01

    Acorn woodpeckers are one of the most conspicuous and abundant birds in California oak forests due to their unique dependence on acorns, a food resource eaten directly and stored in specialized structures on their territories for later use when acorns are no longer present on trees. Parallel long-term studies of the demography and behavior of this species and of...

  12. Temporal dynamics of woodpecker predation on the invasive emerald ash borer (Agrilus planipennis) in North America

    Science.gov (United States)

    Woodpeckers (Picidae) are among the most prevalent natural enemies attacking the invasive emerald ash borer (EAB), Agrilus planipennis Fairmaire, in North America, but there can be considerable variation in the levels of EAB predation on ash trees (Oleaceae: Fraxinus) within and between sites as wel...

  13. Habitat Characteristics of Active and Abandoned Red-Cockaded Woodpecker Colonies

    Science.gov (United States)

    Susan C. Loeb; William D. Pepper; Arlene T. Doyle

    1992-01-01

    Active red-cockaded woodpecker (Picoides borealis) colonies in the Piedmont of Georgia are mature pine stands (mean age = 87 ± 1 yr old) with relatively sparse midstories (mean basal area = 31 ± 3 ft2/ac). Active and abandoned colony sites have similar overstory characteristics, but midstories are significantly denser in...

  14. Effects of radio transmitters on the behavior of Red-headed Woodpeckers.

    Energy Technology Data Exchange (ETDEWEB)

    Vukovich, Mark; Kilgo, John, C.

    2009-05-01

    ABSTRACT. Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior of and use of cavities byRed-headedWoodpeckers (Melanerpes erythrocephalus). Using backpack harnesses, we attached 2.1-g transmitter packages that averaged 3.1% of body weight (range = 2.5–3.6%) to Red-headed Woodpeckers. We observed both radio-tagged (N = 23) and nonradio-tagged (N = 28) woodpeckers and determined the percentage of time spent engaged in each of five behaviors: flight, foraging, perching, preening, and territorial behavior. We found no difference between the two groups in the percentage of time engaged in each behavior. In addition, we found that transmitters had no apparent effect on use of cavities for roosting by radio-tagged woodpeckers (N = 25).We conclude that backpack transmitters weighing less than 3.6% of body weight had no impact on either their behavior or their ability to use cavities.

  15. Systematic review of the influence of foraging habitat on red-cockaded woodpecker reproductive success

    Science.gov (United States)

    James E. Garabedian; Christopher E. Moorman; M. Nils Peterson; John C. Kilgo

    2014-01-01

    Relationships between foraging habitat and reproductive success provide compelling evidence of the contribution of specific vegetative features to foraging habitat quality, a potentially limiting factor for many animal populations. For example, foraging habitat quality likely will gain importance in the recovery of the threatened red-cockaded woodpecker Picoides...

  16. Temperature effect on rose downy mildew development under environmental controlled conditions

    OpenAIRE

    Filgueira D., Juan José; Zambrano, Angélica

    2014-01-01

    The rose downy mildew disease, caused by Peronospora sparsa Berkeley, is one of the most important that affect rose crops in Colombia. To manage this disease, flower growers must deal with high-costs due to the excessive application of fungicides, but without good results. Studies on P. sparsa behavior have shown its narrow relationship with environmental conditions. In this study, the temperature effect was evaluated during the infection and sporulation of P. sparsa in Charlotte leaflets, a ...

  17. Control of litchi downy blight by zeamines produced by Dickeya zeae

    OpenAIRE

    Liao, Lisheng; Zhou, Jianuan; Wang, Huishan; He, Fei; Liu, Shiyin; Jiang, Zide; Chen, Shaohua; Zhang, Lian-Hui

    2015-01-01

    Zeamines (ZMS), a class of polyamine-polyketide-nonribosomal peptide produced by bacterial isolate Dickeya zeae, were shown recently to be potent antibiotics against some bacterial pathogens. In this study, the results indicated that ZMS showed antifungal activity against Peronophythora litchii and other fungal pathogens. The activity of ZMS against the oomycete pathogen P. litchi, which causes the devastating litchi downy blight, was further investigated under in vitro and in vivo conditions...

  18. Monitoring the infective process of the downy mildew causal agent within micropropagated rose plants

    Directory of Open Access Journals (Sweden)

    Sonia Yamile Gómez

    2012-08-01

    Full Text Available Downy mildew in the rose caused by a species of the Peronospora genus is a very restrictive disease for the Colombian greenhouse rose production. The damage observed in the susceptible varieties of commercial rose include symptoms affect young steams and tiny leaves causing reddish and brown spots and defoliation; leading to 10% production losses. The infective behavior of this pathogen was studied with the aim of increasing the knowledge about the biology of the rose downy mildew. The study of the infective process was performed on the Charlotte variety using micropropagated roses inoculated with suspensions of sporangia. A germinal tube was observed during the germination process, it came from a lateral papilla and reached up to 300 microns in length. During this study, the ability of the pathogen to use vascular sieves as communication systems within the plant was determined. Oogonia and antheridia were also observed inside the epidermal cells, and oospores inside the parenchymal tissue close to xylem vessels. To the best of our knowledge, these sexual structures have not been reported on in Colombia before. This study verifies the ability of the downy mildew causal agent to move through the xylem vessels and produce sexual structures, such as oogonia, antheridia and oospores within those tissues.

  19. Daytime Solar Heating Controls Downy Mildew Peronospora belbahrii in Sweet Basil.

    Directory of Open Access Journals (Sweden)

    Yigal Cohen

    Full Text Available The biotrophic oomycete Peronospora belbahrii causes a devastating downy mildew disease in sweet basil. Due to the lack of resistant cultivars current control measures rely heavily on fungicides. However, resistance to fungicides and strict regulation on their deployment greatly restrict their use. Here we report on a 'green' method to control this disease. Growth chamber studies showed that P. belbahrii could hardly withstand exposure to high temperatures; exposure of spores, infected leaves, or infected plants to 35-45 °C for 6-9 hours suppressed its survival. Therefore, daytime solar heating was employed in the field to control the downy mildew disease it causes in basil. Covering growth houses of sweet basil already infected with downy mildew with transparent infra-red-impermeable, transparent polyethylene sheets raised the daily maximal temperature during sunny hours by 11-22 °C reaching 40-58 °C (greenhouse effect. Such coverage, applied for a few hours during 1-3 consecutive days, had a detrimental effect on the survival of P. belbahrii: killing the pathogen and/or suppressing disease progress while enhancing growth of the host basil plants.

  20. Daytime Solar Heating Controls Downy Mildew Peronospora belbahrii in Sweet Basil.

    Science.gov (United States)

    Cohen, Yigal; Rubin, Avia E

    2015-01-01

    The biotrophic oomycete Peronospora belbahrii causes a devastating downy mildew disease in sweet basil. Due to the lack of resistant cultivars current control measures rely heavily on fungicides. However, resistance to fungicides and strict regulation on their deployment greatly restrict their use. Here we report on a 'green' method to control this disease. Growth chamber studies showed that P. belbahrii could hardly withstand exposure to high temperatures; exposure of spores, infected leaves, or infected plants to 35-45 °C for 6-9 hours suppressed its survival. Therefore, daytime solar heating was employed in the field to control the downy mildew disease it causes in basil. Covering growth houses of sweet basil already infected with downy mildew with transparent infra-red-impermeable, transparent polyethylene sheets raised the daily maximal temperature during sunny hours by 11-22 °C reaching 40-58 °C (greenhouse effect). Such coverage, applied for a few hours during 1-3 consecutive days, had a detrimental effect on the survival of P. belbahrii: killing the pathogen and/or suppressing disease progress while enhancing growth of the host basil plants.

  1. Red-cockaded woodpecker colony status and trends on the Angelina, Davy Crockett and Sabine national forests

    Science.gov (United States)

    Richard N. Conner; D. Craig Rudolph

    1989-01-01

    Abundant hardwood midstory, colony isolation, and habitat fragmentation are believed to be the causes for severe population declines of red-cockaded woodpeckers on three national forests in eastern Texas.

  2. Systematic review of the influence of foraging habitat on red-cockaded woodpecker reproductive success.

    Energy Technology Data Exchange (ETDEWEB)

    Garabedian, James E. [North Carolina State University

    2014-04-01

    Relationships between foraging habitat and reproductive success provide compelling evidence of the contribution of specific vegetative features to foraging habitat quality, a potentially limiting factor for many animal populations. For example, foraging habitat quality likely will gain importance in the recovery of the threatened red-cockaded woodpecker Picoides borealis (RCW) in the USA as immediate nesting constraints are mitigated. Several researchers have characterized resource selection by foraging RCWs, but emerging research linking reproductive success (e.g. clutch size, nestling and fledgling production, and group size) and foraging habitat features has yet to be synthesized. Therefore, we reviewed peer-refereed scientific literature and technical resources (e.g. books, symposia proceedings, and technical reports) that examined RCW foraging ecology, foraging habitat, or demography to evaluate evidence for effects of the key foraging habitat features described in the species’ recovery plan on group reproductive success. Fitness-based habitat models suggest foraging habitat with low to intermediate pine Pinus spp. densities, presence of large and old pines, minimal midstory development, and herbaceous groundcover support more productive RCW groups. However, the relationships between some foraging habitat features and RCW reproductive success are not well supported by empirical data. In addition, few regression models account for > 30% of variation in reproductive success, and unstandardized multiple and simple linear regression coefficient estimates typically range from -0.100 to 0.100, suggesting ancillary variables and perhaps indirect mechanisms influence reproductive success. These findings suggest additional research is needed to address uncertainty in relationships between foraging habitat features and RCW reproductive success and in the mechanisms underlying those relationships.

  3. A Risk-Based Approach to Evaluating Wildlife Demographics for Management in a Changing Climate: A Case Study of the Lewis's Woodpecker

    Science.gov (United States)

    Towler, Erin; Saab, Victoria A.; Sojda, Richard S.; Dickinson, Katherine; Bruyère, Cindy L.; Newlon, Karen R.

    2012-12-01

    Given the projected threat that climate change poses to biodiversity, the need for proactive response efforts is clear. However, integrating uncertain climate change information into conservation planning is challenging, and more explicit guidance is needed. To this end, this article provides a specific example of how a risk-based approach can be used to incorporate a species' response to climate into conservation decisions. This is shown by taking advantage of species' response (i.e., impact) models that have been developed for a well-studied bird species of conservation concern. Specifically, we examine the current and potential impact of climate on nest survival of the Lewis's Woodpecker ( Melanerpes lewis) in two different habitats. To address climate uncertainty, climate scenarios are developed by manipulating historical weather observations to create ensembles (i.e., multiple sequences of daily weather) that reflect historical variability and potential climate change. These ensembles allow for a probabilistic evaluation of the risk posed to Lewis's Woodpecker nest survival and are used in two demographic analyses. First, the relative value of each habitat is compared in terms of nest survival, and second, the likelihood of exceeding a critical population threshold is examined. By embedding the analyses in a risk framework, we show how management choices can be made to be commensurate with a defined level of acceptable risk. The results can be used to inform habitat prioritization and are discussed in the context of an economic framework for evaluating trade-offs between management alternatives.

  4. A risk-based approach to evaluating wildlife demographics for management in a changing climate: A case study of the Lewis's Woodpecker

    Science.gov (United States)

    Towler, Erin; Saab, Victoria A.; Sojda, Richard S.; Dickinson, Katherine; Bruyere, Cindy L.; Newlon, Karen R.

    2012-01-01

    Given the projected threat that climate change poses to biodiversity, the need for proactive response efforts is clear. However, integrating uncertain climate change information into conservation planning is challenging, and more explicit guidance is needed. To this end, this article provides a specific example of how a risk-based approach can be used to incorporate a species' response to climate into conservation decisions. This is shown by taking advantage of species' response (i.e., impact) models that have been developed for a well-studied bird species of conservation concern. Specifically, we examine the current and potential impact of climate on nest survival of the Lewis's Woodpecker (Melanerpes lewis) in two different habitats. To address climate uncertainty, climate scenarios are developed by manipulating historical weather observations to create ensembles (i.e., multiple sequences of daily weather) that reflect historical variability and potential climate change. These ensembles allow for a probabilistic evaluation of the risk posed to Lewis's Woodpecker nest survival and are used in two demographic analyses. First, the relative value of each habitat is compared in terms of nest survival, and second, the likelihood of exceeding a critical population threshold is examined. By embedding the analyses in a risk framework, we show how management choices can be made to be commensurate with a defined level of acceptable risk. The results can be used to inform habitat prioritization and are discussed in the context of an economic framework for evaluating trade-offs between management alternatives.

  5. Nitric oxide donor seed priming enhances defense responses and induces resistance against pearl millet downy mildew disease

    DEFF Research Database (Denmark)

    Manjunatha, G.; Raj, S. Niranjan; Shetty, Nandini Prasad

    2008-01-01

    experiments with NO donors showed no adverse effect either on the host or pathogen. Aqueous SNP seed treatment with or without polyethylene glycol (PEG) priming was the most effective in inducing the host resistance against downy mildew both under greenhouse and field conditions. Potassium Ferrocyanide......Nitric oxide (NO) donors Nitroso-R-Salt, 2-Nitroso-1-Naphthol and Sodium Nitro Prusside (SNP) were evaluated for their effectiveness in protecting pearl millet [(Pennisetum glaucum L.) R. Br.] plants against downy mildew disease caused by Sclerospora graminicola [(Sacc). Schroet]. Optimization......, a structural analog of NO donor lacking NO moiety failed to protect the pearl millet plants from downy mildew indicating a role for NO in induced host resistance. Spatio-temporal studies corroborated that the protection offered by NO donor treatment was systemic in nature and a minimum of 3-day time gap...

  6. Correlations between the contents of phytic acid and inorganic phosphorous and downy mildew resistance of corn inbred lines

    Directory of Open Access Journals (Sweden)

    Pantipa Na Chiangmai

    2015-10-01

    Full Text Available Seeds of corn inbred lines collected at the National Corn and Sorghum Research Center (NCSRC, Kasetsart University, were analyzed to determine the contents of phytic acid (PA and inorganic phosphorous (InP. These 28 and 29 inbred lines were cultivated at the NCSRC (in the 2008 late rainy season and 2009 early rainy season to evaluate their resistance to corn downy mildew caused by Peronosclerospora sorghi. Results showed that the values of the PA, InP contents and downy mildew infection were statistically different among these inbred lines in both seasons. However, there were no correlations between the contents of either PA or InP and downy mildew infection.

  7. Simple sequence repeat markers useful for sorghum downy mildew (Peronosclerospora sorghi and related species

    Directory of Open Access Journals (Sweden)

    Odvody Gary N

    2008-11-01

    Full Text Available Abstract Background A recent outbreak of sorghum downy mildew in Texas has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically point out the need for simply scored markers in order to differentiate among isolates and species, and to study the population structure within these obligate oomycetes. Here we present the initial results from the use of a biotin capture method to discover, clone and develop PCR primers that permit the use of simple sequence repeats (microsatellites to detect differences at the DNA level. Results Among the 55 primers pairs designed from clones from pathotype 3 of P. sorghi, 36 flanked microsatellite loci containing simple repeats, including 28 (55% with dinucleotide repeats and 6 (11% with trinucleotide repeats. A total of 22 microsatellites with CA/AC or GT/TG repeats were the most abundant (40% and GA/AG or CT/TC types contribute 15% in our collection. When used to amplify DNA from 19 isolates from P. sorghi, as well as from 5 related species that cause downy mildew on other hosts, the number of different bands detected for each SSR primer pair using a LI-COR- DNA Analyzer ranged from two to eight. Successful cross-amplification for 12 primer pairs studied in detail using DNA from downy mildews that attack maize (P. maydis & P. philippinensis, sugar cane (P. sacchari, pearl millet (Sclerospora graminicola and rose (Peronospora sparsa indicate that the flanking regions are conserved in all these species. A total of 15 SSR amplicons unique to P. philippinensis (one of the potential threats to US maize production were detected, and these have potential for development of diagnostic tests. A total of 260 alleles were obtained using 54 microsatellites primer combinations, with an average of 4.8 polymorphic markers per SSR across 34

  8. Simple sequence repeat markers useful for sorghum downy mildew (Peronosclerospora sorghi) and related species.

    Science.gov (United States)

    Perumal, Ramasamy; Nimmakayala, Padmavathi; Erattaimuthu, Saradha R; No, Eun-Gyu; Reddy, Umesh K; Prom, Louis K; Odvody, Gary N; Luster, Douglas G; Magill, Clint W

    2008-11-29

    A recent outbreak of sorghum downy mildew in Texas has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically point out the need for simply scored markers in order to differentiate among isolates and species, and to study the population structure within these obligate oomycetes. Here we present the initial results from the use of a biotin capture method to discover, clone and develop PCR primers that permit the use of simple sequence repeats (microsatellites) to detect differences at the DNA level. Among the 55 primers pairs designed from clones from pathotype 3 of P. sorghi, 36 flanked microsatellite loci containing simple repeats, including 28 (55%) with dinucleotide repeats and 6 (11%) with trinucleotide repeats. A total of 22 microsatellites with CA/AC or GT/TG repeats were the most abundant (40%) and GA/AG or CT/TC types contribute 15% in our collection. When used to amplify DNA from 19 isolates from P. sorghi, as well as from 5 related species that cause downy mildew on other hosts, the number of different bands detected for each SSR primer pair using a LI-COR- DNA Analyzer ranged from two to eight. Successful cross-amplification for 12 primer pairs studied in detail using DNA from downy mildews that attack maize (P. maydis & P. philippinensis), sugar cane (P. sacchari), pearl millet (Sclerospora graminicola) and rose (Peronospora sparsa) indicate that the flanking regions are conserved in all these species. A total of 15 SSR amplicons unique to P. philippinensis (one of the potential threats to US maize production) were detected, and these have potential for development of diagnostic tests. A total of 260 alleles were obtained using 54 microsatellites primer combinations, with an average of 4.8 polymorphic markers per SSR across 34 Peronosclerospora, Peronospora and Sclerospora

  9. Functional visual sensitivity to ultraviolet wavelengths in the Pileated Woodpecker (Dryocopus pileatus), and its influence on foraging substrate selection

    Science.gov (United States)

    O'Daniels, Sean T.; Kesler, Dylan C.; Mihail, Jeanne D.; Webb, Elisabeth B.; Werner, Scott J.

    2017-01-01

    Most diurnal birds are presumed visually sensitive to near ultraviolet (UV) wavelengths, however, controlled behavioral studies investigating UV sensitivity remain few. Although woodpeckers are important as primary cavity excavators and nuisance animals, published work on their visual systems is limited. We developed a novel foraging-based behavioral assay designed to test UV sensitivity in the Pileated Woodpecker (Dryocopus pileatus). We acclimated 21 wild-caught woodpeckers to foraging for frozen mealworms within 1.2 m sections of peeled cedar (Thuja spp.) poles. We then tested the functional significance of UV cues by placing frozen mealworms behind UV-reflective covers, UV-absorptive covers, or decayed red pine substrates within the same 1.2 m poles in independent experiments. Behavioral responses were greater toward both UV-reflective and UV-absorptive substrates in three experiments. Study subjects therefore reliably differentiated and attended to two distinct UV conditions of a foraging substrate. Cue-naïve subjects showed a preference for UV-absorptive substrates, suggesting that woodpeckers may be pre-disposed to foraging from such substrates. Behavioral responses were greater toward decayed pine substrates (UV-reflective) than sound pine substrates suggesting that decayed pine can be a useful foraging cue. The finding that cue-naïve subjects selected UV-absorbing foraging substrates has implications for ecological interactions of woodpeckers with fungi. Woodpeckers transport fungal spores, and communication methods analogous to those of plant-pollinator mutualisms (i.e. UV-absorbing patterns) may have evolved to support woodpecker-fungus mutualisms.

  10. Relationship of Course Woody Debris to Red-Cockaded Woodpecker Prey Diversity and Abundance

    Energy Technology Data Exchange (ETDEWEB)

    Horn, G.S.

    1999-09-03

    The abundance of diversity of prey commonly used by the red-cockaded woodpecker were monitored in experimental plots in which course woody debris was manipulated. In one treatment, all the woody debris over four inches was removed. In the second treatment, the natural amount of mortality remained intact. The overall diversity of prey was unaffected; however, wood roaches were significantly reduced by removal of woody debris. The latter suggests that intensive utilizations or harvesting practices may reduce foraging.

  11. Red-cockaded woodpecker male/female foraging differences in young forest stands.

    Energy Technology Data Exchange (ETDEWEB)

    Franzreb, Kathleen, E.

    2010-07-01

    ABSTRACT The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinus spp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in contrast to earlier foraging behavior studies that focused on more mature forest. The Redcockaded Woodpecker at the Savannah River site is intensively managed including monitoring, translocation, and installation of artificial cavity inserts for roosting and nesting. Over a 3-year period, 6,407 foraging observations covering seven woodpecker family groups were recorded during all seasons of the year and all times of day. The most striking differences occurred in foraging method (males usually scaled [45% of observations] and females mostly probed [47%]),substrate used (females had a stronger preference [93%] for the trunk than males [79%]), and foraging height from the ground (mean 6 SE foraging height was higher for males [11.1 6 0.5 m] than females [9.8 6 0.5 m]). Niche overlap between males and females was lowest for substrate (85.6%) and foraging height (87.8%), and highest for tree species (99.0%), tree condition (98.3%), and tree height (96.4%). Both males and females preferred to forage in older, large pine trees. The habitat available at the Savannah River Site was considerably younger than at most other locations, but the pattern of male/female habitat partitioning observed was similar to that documented elsewhere within the range attesting to the species’ ability to adjust behaviorally.

  12. The red-cockaded woodpecker on the Savannah River Site: Aspects of reproductive success.

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Peter A; Imm, Donald, W.; Jarvis, William L

    2004-12-31

    Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 5. Status and Trends of Populations. Pp 224-229. Abstract: The red-cockaded woodpecker (Picoides borealis) population on the Savannah River Site has been closely monitored and studied over the last 17 years. In 1985, the USDA Forest Service Southern Research Station was given responsibility to study and manage this population in an effort to prevent its extirpation. In December 1985, there were only 4 individuals on the site: 1 pair and 2 solitary males. The population had increased to a total of 175 individuals in 42 active clusters in 2002. Although this represents a very successful recovery effort, there has been substantial annual variation in nesting survival from banding to fledging. Data were analyzed to more completely understand the factors affecting reproduction. No significant effects of age of the breeding male and female, years paired, number of helpers, habitat quality, number of nestings, and time of nest initiation were found when comparing reproductive success in 117 nesting attempts from 1999 to 2002. However, the number of neighboring groups had a direct effect on mortality rates, possibly demonstrating the importance of cluster spacing.

  13. The Potential for Long-Term Sustainability in Seminatural Forestry: A Broad Perspective Based on Woodpecker Populations

    Science.gov (United States)

    Lõhmus, Asko; Nellis, Renno; Pullerits, Mirjam; Leivits, Meelis

    2016-03-01

    We assessed ecological sustainability of seminatural forestry by analyzing 80-year dynamics and the current distribution of all woodpecker species in Estonia. We found that, despite the clear-cutting-based forestry system, woodpeckers inhabited commercial seminatural forests in substantial numbers, including the species generally considered vulnerable to timber harvesting. The only negative trend, a drastic decline in the Green Woodpecker, paralleled the loss of seminatural, wooded grasslands and is mostly an issue for landscape planning and agricultural land use. Major silvicultural factors supporting other species in commercial forests include natural regeneration with multiple native tree species and deadwood abundance. In such context, the main role of protected areas is to provide ecological resilience; however, we estimated that the current strict reserves could further double their carrying capacities for woodpeckers through successional recovery and, perhaps, active restoration. The long time series used were instrumental in detecting unexpected dynamics and the impacts of climatically extreme years. We conclude that (1) seminatural forestry can serve as a basis for reconciling timber harvesting and biodiversity protection at the landscape scale, given appropriate attention to key structures and landscape zoning and (2) woodpeckers represent a biological indicator system for the sustainability of forest landscapes in Europe.

  14. Foraging behavior of pileated woodpeckers in partial cut and uncut bottomland hardwood forest

    Science.gov (United States)

    Newell, P.; King, Sammy L.; Kaller, Michael D.

    2009-01-01

    In bottomland hardwood forests, partial cutting techniques are increasingly advocated and used to create habitat for priority wildlife like Louisiana black bear (Ursus americanus luteolus), white-tailed deer (Odocoileus virginianus), and Neotropical migrants. Although partial cutting may be beneficial to some species, those that use dead wood may be negatively affected since large diameter and poor quality trees (deformed, moribund, or dead) are rare, but normally targeted for removal. On the other hand, partial cutting can create dead wood if logging slash is left on-site. We studied foraging behavior of pileated woodpeckers (Dryocopus pileatus) in one- and two-year-old partial cuts designed to benefit priority species and in uncut forest during winter, spring, and summer of 2006 and 2007 in Louisiana. Males and females did not differ in their use of tree species, dbh class, decay class, foraging height, use of foraging tactics or substrate types; however, males foraged on larger substrates than females. In both partial cut and uncut forest, standing live trees were most frequently used (83% compared to 14% for standing dead trees and 3% for coarse woody debris); however, dead trees were selected (i.e. used out of proportion to availability). Overcup oak (Quercus lyrata) and bitter pecan (Carya aquatica) were also selected and sugarberry (Celtis laevigata) avoided. Pileated woodpeckers selected trees >= 50 cm dbh and avoided trees in smaller dbh classes (10-20 cm). Density of selected foraging substrates was the same in partial cut and uncut forest. Of the foraging substrates, woodpeckers spent 54% of foraging time on live branches and boles, 37% on dead branches and boles, and 9% on vines. Of the foraging tactics, the highest proportion of foraging time was spent excavating (58%), followed by pecking (14%), gleaning (14%), scaling (7%), berry-eating (4%), and probing (3%). Woodpecker use of foraging tactics and substrates, and foraging height and substrate

  15. The relative effects of habitat loss and fragmentation on population genetic variation in the red-cockaded woodpecker (Picoides borealis).

    Science.gov (United States)

    Bruggeman, Douglas J; Wiegand, Thorsten; Fernández, Néstor

    2010-09-01

    The relative influence of habitat loss, fragmentation and matrix heterogeneity on the viability of populations is a critical area of conservation research that remains unresolved. Using simulation modelling, we provide an analysis of the influence both patch size and patch isolation have on abundance, effective population size (N(e)) and F(ST). An individual-based, spatially explicit population model based on 15 years of field work on the red-cockaded woodpecker (Picoides borealis) was applied to different landscape configurations. The variation in landscape patterns was summarized using spatial statistics based on O-ring statistics. By regressing demographic and genetics attributes that emerged across the landscape treatments against proportion of total habitat and O-ring statistics, we show that O-ring statistics provide an explicit link between population processes, habitat area, and critical thresholds of fragmentation that affect those processes. Spatial distances among land cover classes that affect biological processes translated into critical scales at which the measures of landscape structure correlated best with genetic indices. Therefore our study infers pattern from process, which contrasts with past studies of landscape genetics. We found that population genetic structure was more strongly affected by fragmentation than population size, which suggests that examining only population size may limit recognition of fragmentation effects that erode genetic variation. If effective population size is used to set recovery goals for endangered species, then habitat fragmentation effects may be sufficiently strong to prevent evaluation of recovery based on the ratio of census:effective population size alone.

  16. Discovery of a New Fungicide Candidate through Lead Optimization of Pyrimidinamine Derivatives and Its Activity against Cucumber Downy Mildew.

    Science.gov (United States)

    Guan, Aiying; Wang, Mingan; Yang, Jinlong; Wang, Lizeng; Xie, Yong; Lan, Jie; Liu, Changling

    2017-12-13

    Downy mildew is one of the most highly destructive of the diseases that cause damage to fruits and vegetables. Because of the continual development of resistance, it is important to discover new fungicides with different modes of action from existing fungicides for the control of downy mildew. This study is a continuation of our previous work on the novel pyrimidinamine lead compound, 9, and includes field trials for the identification of the optimal candidate. A new compound, 1c, was obtained, which gave a lower EC 50 value (0.10 mg/L) against downy mildew than lead compound 9 (0.19 mg/L) and the commercial fungicides diflumetorim, dimethomorph, and cyazofamid (1.01-23.06 mg/L). Compound 1c displayed similar broad-spectrum fungicidal activity to compound 9 but better field efficacy than compound 9, cyazofamid, and flumorph. The present work indicates that pyrimidinamine compound 1c is a candidate for further development as a commercial fungicide for the control of downy mildew.

  17. Large-scale downy brome treatments alter plant-soil relationships and promote perennial grasses in salt desert shrublands

    Science.gov (United States)

    The interrelationship between invasive annual grass abundance and soil resource availability varies spatially and temporally within ecosystems and may be altered by land treatments. We evaluated these relationships in two salt desert landscapes where the local abundance of Bromus tectorum L. (downy...

  18. Downy Brome (Bromus tectorum L. and Broadleaf Weed Control in Winter Wheat with Acetolactate Synthase-Inhibiting Herbicides

    Directory of Open Access Journals (Sweden)

    Patrick W. Geier

    2013-04-01

    Full Text Available A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS-inhibiting herbicides for downy brome (Bromus tectorum L. and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, propoxycarbazone-Na at 44 g ai ha−1, premixed propoxycarbazone-Na & mesosulfuron-methyl at 27 g ai ha−1, and sulfosulfuron at 35 g ai ha−1. The herbicides were applied postemergence in fall and spring seasons. Averaged over time of application, no herbicide controlled downy brome more than 78% in any year. When downy brome densities were high, control was less than 60%. Pyroxsulam controlled downy brome greater than or similar to other herbicides tested. Flixweed (Descurainia sophia L., blue mustard [Chorispora tenella (Pallas DC.], and henbit (Lamium amplexicaule L. control did not differ among herbicide treatments. All herbicides tested controlled flixweed and blue mustard at least 87% and 94%, respectively. However, none of the herbicides controlled henbit more than 73%. Fall herbicide applications improved weed control compared to early spring applications; improvement ranged from 3% to 31% depending on the weed species. Henbit control was greatly decreased by delaying herbicide applications until spring compared to fall applications (49% vs. 80% control. Herbicide injury was observed in only two instances. The injury was ≤13% with no difference between herbicides and the injury did not impact final plant height or grain yield.

  19. Using next-generation sequencing to develop molecular diagnostics for Pseudoperonospora cubensis, the cucurbit downy mildew pathogen

    Science.gov (United States)

    Advances in Next Generation Sequencing (NGS) allow for rapid development of genomics resources needed to generate molecular diagnostics assays for infectious agents. NGS approaches are particularly helpful for organisms that cannot be cultured, such as the downy mildew pathogens, a group of biotrop...

  20. Nutritional improvement of the rose handling Peronospora Sparsa Berkeley, causal agent of downy mildew

    International Nuclear Information System (INIS)

    Castillo Carlos Fernando; Alvarez Elizabeth; Gomez Eduardo; Llano, German A; Castano Zapata, Jairo

    2010-01-01

    Nutritional solutions, silica, resistance, downy mildew. The downy mildew (Peronospora sparsa), is one of the most important diseases of rose in Colombia, causing losses up to 8%. The objective of this research was to determine a preventive control of the disease, through the improvement of the nutritional balance of the plant. The first phase, involved the effect of different concentrations of N, K, Ca, B and Mn, on the incidence and severity of the disease, and in the second one, the evaluation of the best five treatments of the first phase. The treatments were applied to the varieties Charlotte, Classy and Malibu during 4 weeks, using a splitting plot design with six replications. After one month the plants were inoculated with the fungus at a concentration of 3x104 sporangia mL.The results of the area under the disease progress curve (AUDPC), showed that the plants of Charlotte with 200 ppm of Si had the lowest expression of the disease. In Classy, the best treatment was the standard solution, demonstrating that the effects of the treatments depend of the variety. Charlotte and Malibu showed susceptibility, while Classy, partial resistance to the disease.

  1. Transcriptome and Small RNAome Dynamics during a Resistant and Susceptible Interaction between Cucumber and Downy Mildew

    Directory of Open Access Journals (Sweden)

    Alyssa Burkhardt

    2016-03-01

    Full Text Available Cucumber ( L. downy mildew, caused by the obligate oomycete pathogen (Berk. and Curt. Rostov., is the primary factor limiting cucumber production. Although sources of resistance have been identified, such as plant introduction line PI 197088, the genes and processes involved in mediating resistance are still unknown. In the current study, we conducted a comprehensive transcriptome and small RNAome analysis of a resistant (PI 197088 and susceptible (‘Vlaspik’ cucumber during a time course of infection using Illumina sequencing. We identified significantly differentially expressed (DE genes within and between resistant and susceptible cucumber leaves over a time course of infection. Weighted gene correlation network analyses (WGCNA created coexpression modules containing genes with unique expression patterns between Vlaspik and PI 197088. Recurring data trends indicated that resistance to cucumber downy mildew is associated with earlier response to the pathogen, hormone signaling, and regulation of nutrient supply. Candidate resistance genes were identified from multiple transcriptome analyses and literature support. Additionally, parallel sequencing of small RNAs (sRNAs from cucumber and during the infection time course was used to identify and quantify novel and existing microRNA (miRNA in both species. Predicted miRNA targets of cucumber transcripts suggest a complex interconnectedness of gene expression regulation in this plant–pathogen system. This work bioinformatically uncovered gene expression patterns involved in the mediation of or response to resistance. Herein, we provide the foundation for future work to validate candidate resistance genes and miRNA-based regulation proposed in this study.

  2. Control of downy mildew in greenhouse-grown cucumbers using blue photoselective polyethylene sheets

    International Nuclear Information System (INIS)

    Reuveni, R.; Raviv, M.

    1997-01-01

    Six types of polyethylene sheets with or without a blue pigment, having an absorption peak at the yellow part of the spectrum (580 nm), in combination with three levels of UV-B (280 to 320 nm) absorbance, were investigated for their effects on sporangial production and colonization of Pseudoperonospora cubensis on cucumbers in growth chambers. The effect of these photoselective sheets on the epidemiology of downy mildew in greenhouse-grown cucumbers has been investigated in several locations. The addition of the blue pigment to the films resulted in a significant inhibition of colonization and sporangial production of P. cubensis, whereas filtration of the UV spectrum enhanced the colonization but had no effect on the sporangial production. The appearance of the first symptom-bearing plants was delayed under the blue covers, and consequently, a significant reduction in the disease incidence of downy mildew was recorded under all blue sheets at each corresponding level of UV-B transmittance in five different field experiments through four seasons. Regardless of the differences in disease incidence, there were no significant differences among the yields that were obtained under the various sheets, probably due to the lower photosynthetically active radiation transmissivity of the blue films. The optimal features required for a desirable commercial sheet are discussed

  3. Morphological and molecular characterization of the causal agent of downy mildew on Quinoa (Chenopodium quinoa).

    Science.gov (United States)

    Choi, Young-Joon; Danielsen, Solveig; Lübeck, Mette; Hong, Seung-Beom; Delhey, Rolf; Shin, Hyeon-Dong

    2010-05-01

    Downy mildew is an economically important and widespread disease in quinoa (Chenopodium quinoa) growing areas. Although in many studies Peronospora farinosa is most commonly regarded as the causal agent of the disease, identification and classification of the pathogen remain still uncertain due to its taxonomic confusion. Thirty-six Peronospora isolates from quinoa with different geographic origins including Argentina, Bolivia, Denmark, Ecuador, and Peru were morphologically and molecularly compared with Peronospora species from other Chenopodium species. The morphology of three herbarium specimens was similar to that of P. variabilis, which originated from C. album, characterized by flexuous to curved ultimate branchlets and pedicellated conidia. Phylogenetic analysis based on ITS rDNA sequences also placed the quinoa pathogen within the same clade as P. variabilis. Within the ITS rDNA sequences of the quinoa pathogens, two base substitutions were found, which separated the majority of the Danish isolates from isolates from South America, but no sequence difference was found among the isolates from different cultivars of quinoa. The present results indicate that the pathogen responsible for the quinoa downy mildew is identical to Peronospora variabilis and that it should not be lumped with P. farinosa as claimed previously by most studies.

  4. The Role of Wildfire, Prescribed Fire, and Mountain Pine Beetle Infestations on the Population Dynamics of Black-Backed Woodpeckers in the Black Hills, South Dakota

    Science.gov (United States)

    Rota, Christopher T.; Millspaugh, Joshua J.; Rumble, Mark A.; Lehman, Chad P.; Kesler, Dylan C.

    2014-01-01

    Wildfire and mountain pine beetle infestations are naturally occurring disturbances in western North American forests. Black-backed woodpeckers (Picoides arcticus) are emblematic of the role these disturbances play in creating wildlife habitat, since they are strongly associated with recently-killed forests. However, management practices aimed at reducing the economic impact of natural disturbances can result in habitat loss for this species. Although black-backed woodpeckers occupy habitats created by wildfire, prescribed fire, and mountain pine beetle infestations, the relative value of these habitats remains unknown. We studied habitat-specific adult and juvenile survival probabilities and reproductive rates between April 2008 and August 2012 in the Black Hills, South Dakota. We estimated habitat-specific adult and juvenile survival probability with Bayesian multi-state models and habitat-specific reproductive success with Bayesian nest survival models. We calculated asymptotic population growth rates from estimated demographic rates with matrix projection models. Adult and juvenile survival and nest success were highest in habitat created by summer wildfire, intermediate in MPB infestations, and lowest in habitat created by fall prescribed fire. Mean posterior distributions of population growth rates indicated growing populations in habitat created by summer wildfire and declining populations in fall prescribed fire and mountain pine beetle infestations. Our finding that population growth rates were positive only in habitat created by summer wildfire underscores the need to maintain early post-wildfire habitat across the landscape. The lower growth rates in fall prescribed fire and MPB infestations may be attributed to differences in predator communities and food resources relative to summer wildfire. PMID:24736502

  5. The role of wildfire, prescribed fire, and mountain pine beetle infestations on the population dynamics of black-backed woodpeckers in the black hills, South Dakota.

    Directory of Open Access Journals (Sweden)

    Christopher T Rota

    Full Text Available Wildfire and mountain pine beetle infestations are naturally occurring disturbances in western North American forests. Black-backed woodpeckers (Picoides arcticus are emblematic of the role these disturbances play in creating wildlife habitat, since they are strongly associated with recently-killed forests. However, management practices aimed at reducing the economic impact of natural disturbances can result in habitat loss for this species. Although black-backed woodpeckers occupy habitats created by wildfire, prescribed fire, and mountain pine beetle infestations, the relative value of these habitats remains unknown. We studied habitat-specific adult and juvenile survival probabilities and reproductive rates between April 2008 and August 2012 in the Black Hills, South Dakota. We estimated habitat-specific adult and juvenile survival probability with Bayesian multi-state models and habitat-specific reproductive success with Bayesian nest survival models. We calculated asymptotic population growth rates from estimated demographic rates with matrix projection models. Adult and juvenile survival and nest success were highest in habitat created by summer wildfire, intermediate in MPB infestations, and lowest in habitat created by fall prescribed fire. Mean posterior distributions of population growth rates indicated growing populations in habitat created by summer wildfire and declining populations in fall prescribed fire and mountain pine beetle infestations. Our finding that population growth rates were positive only in habitat created by summer wildfire underscores the need to maintain early post-wildfire habitat across the landscape. The lower growth rates in fall prescribed fire and MPB infestations may be attributed to differences in predator communities and food resources relative to summer wildfire.

  6. The role of wildfire, prescribed fire, and mountain pine beetle infestations on the population dynamics of black-backed woodpeckers in the black hills, South Dakota.

    Science.gov (United States)

    Rota, Christopher T; Millspaugh, Joshua J; Rumble, Mark A; Lehman, Chad P; Kesler, Dylan C

    2014-01-01

    Wildfire and mountain pine beetle infestations are naturally occurring disturbances in western North American forests. Black-backed woodpeckers (Picoides arcticus) are emblematic of the role these disturbances play in creating wildlife habitat, since they are strongly associated with recently-killed forests. However, management practices aimed at reducing the economic impact of natural disturbances can result in habitat loss for this species. Although black-backed woodpeckers occupy habitats created by wildfire, prescribed fire, and mountain pine beetle infestations, the relative value of these habitats remains unknown. We studied habitat-specific adult and juvenile survival probabilities and reproductive rates between April 2008 and August 2012 in the Black Hills, South Dakota. We estimated habitat-specific adult and juvenile survival probability with Bayesian multi-state models and habitat-specific reproductive success with Bayesian nest survival models. We calculated asymptotic population growth rates from estimated demographic rates with matrix projection models. Adult and juvenile survival and nest success were highest in habitat created by summer wildfire, intermediate in MPB infestations, and lowest in habitat created by fall prescribed fire. Mean posterior distributions of population growth rates indicated growing populations in habitat created by summer wildfire and declining populations in fall prescribed fire and mountain pine beetle infestations. Our finding that population growth rates were positive only in habitat created by summer wildfire underscores the need to maintain early post-wildfire habitat across the landscape. The lower growth rates in fall prescribed fire and MPB infestations may be attributed to differences in predator communities and food resources relative to summer wildfire.

  7. Resurgence of Pseudoperonospora cubensis: The Causal Agent of Cucurbit Downy Mildew.

    Science.gov (United States)

    Cohen, Yigal; Van den Langenberg, Kyle M; Wehner, Todd C; Ojiambo, Peter S; Hausbeck, Mary; Quesada-Ocampo, Lina M; Lebeda, Aleš; Sierotzki, Helge; Gisi, Ulrich

    2015-07-01

    The downy mildew pathogen, Pseudoperonospora cubensis, which infects plant species in the family Cucurbitaceae, has undergone major changes during the last decade. Disease severity and epidemics are far more destructive than previously reported, and new genotypes, races, pathotypes, and mating types of the pathogen have been discovered in populations from around the globe as a result of the resurgence of the disease. Consequently, disease control through host plant resistance and fungicide applications has become more complex. This resurgence of P. cubensis offers challenges to scientists in many research areas including pathogen biology, epidemiology and dispersal, population structure and population genetics, host preference, host-pathogen interactions and gene expression, genetic host plant resistance, inheritance of host and fungicide resistance, and chemical disease control. This review serves to summarize the current status of this major pathogen and to guide future management and research efforts within this pathosystem.

  8. Comparative effects of glyphosate and atrazine in chloroplast ultrastructure of wheat and downy brome

    International Nuclear Information System (INIS)

    Auge, R.M.; Gealy, D.R.; Ogg, A.G.; Franceschi, V.R.

    1987-01-01

    Developing and mature leaves of winter wheat (Triticum aestivum L. var. Daws) and the weed species downy brome (Bromus tectorum L.) were subjected to 10 mM (foliar application) and 1 mM (root application) herbicide solutions. Glyphosate (N-(phosphonomethyl) glycine) and atrazine (2-chloro-4-(ethyl-amino)-6-(isopropylamino)-s-triazine) were prepared in a carrier composed of 5% soybean oil concentrate, 35% acetone and 60% water. Penetration experiments with 3 H-labelled herbicides assessed what percentage of herbicide entered leaves, and microautoradiography was used to determine qualitatively how much herbicide was present in the sections viewed with TEM. Tissue was excised at 4, 18, 62 and 200 hours, and then either freeze-substituted or fixed chemically. Ultrastructural effects of each herbicide on chloroplasts from leaves of newly-germinated seedlings and of well-tillered plants are depicted and discussed. Temporal differences in response of chloroplasts to each herbicide are noted

  9. White blister rusts and downy mildews from bajaur agency fata, with some new records from pakistan

    International Nuclear Information System (INIS)

    Haq, M.A.; Shahzad, S.

    2015-01-01

    In a species diversity study of Oomycyctes of Bajaur Agency FATA, Pakistan, infection of white blister rusts and downy mildews recorded on three cultivated and four wild plants. Capsella bursa-pastoris showed mixed infection of Albugo candida and Hyaloperonospora parasitica (syn: Peronospora parasitica). Similarly, A. candida and H. brassicae (syn: P. brassicae) parasitized Brassica campestris. Wilsoniana portulacae (syn: Albugo portulacae) and W. occidentalis com. nov. (syn: Albugo occidentalis) recovered from Portulaca oleracea and Spinacia oleracea, respectively. Bremia taraxaci, B. sonchicola and B. saussureae recorded on Taraxicum officinale, Sonchus sp., and Saussurea sp., respectively. All these obligate parasites are new records from Bajaur Agency, while H. parasitica, W. occidentalis, B. taraxaci, and B. saussureae on the mentioned hosts are new records from Pakistan. (author)

  10. Forest landscapes: Their effect on the interaction of the southern pine beetle and red-cockaded woodpecker

    Science.gov (United States)

    Robert N. Coulson; Maria D. Guzman; Karen Skordinski; Jeffrey W. Fitzgerald; Richard N. Conner; D. Craig Rudolph; Forrest L. Oliveria; Douglas F. Wunneburger; Paul E. Pulley

    1999-01-01

    The nature of the interaction of the southern pine beetle and red-cockaded woodpecker was investidgated using spatially explicit information on the structure of a forest landscape mosiac and knowledge of the behavior of the two organisms. This interaction is the basis for defind functional heterogeneity - how an organism perceives and responds to the elements forming...

  11. Implications of home-range estimation in the management of red-cockaded woodpeckers in South Carolina

    Science.gov (United States)

    Kathleen E. Franzreb

    2006-01-01

    I undertook a behavioral study to determine red-cockaded woodpecker (Picoides borealis) home-range size at the Savannah River Site, South Carolina, USA. In this location, because much of the timber was harvested in the late 1940s and early 1950s, the available habitat largely consisted of younger trees (e.g., less than 45 years old), not generally...

  12. Foraging plasticity by a keystone excavator, the white-headed woodpecker, in managed forests: Are there consequences for productivity?

    Science.gov (United States)

    Teresa J. Lorenz; Kerri T. Vierling; Jeffrey M. Kozma; Janet E. Millard

    2016-01-01

    Information on the foraging ecology of animals is important for conservation and management, particularly for keystone species whose presence affects ecosystem health. We examined foraging by an at-risk cavity excavator, the white-headed woodpecker (Picoides albolarvatus). The foraging needs of this species are used to inform management of...

  13. Between-year breeding dispersal by White-headed Woodpeckers: A caution about using color bands to estimate survival

    Science.gov (United States)

    Teresa J Lorenz

    2016-01-01

    Between-year breeding dispersal has not been previously documented in White-headed Woodpeckers (Picoides albolarvatus). Therefore, resightings of color-banded adults on previous years’ breeding territories have been considered a means of estimating annual adult survival. From 2013 to 2015, I observed 2 cases of between-year breeding dispersal by...

  14. Use of a barbed tool by an adult and a juvenile woodpecker finch (Cactospiza pallida).

    Science.gov (United States)

    Sabine, Tebbich; Irmgard, Teschke; Erica, Cartmill; Sophia, Stankewitz

    2012-02-01

    Here we describe the modification and use of a new tool type in the woodpecker finch (Cactospiza pallida). This species is known to habitually use twigs or cactus spines to extract arthropods out of tree holes. We observed an adult and a juvenile bird using several barbed twigs from introduced blackberry bushes (Rubus niveus) which the adult bird had first modified by removing leaves and side twigs. The barbs of blackberry tools provide a novel functional feature not present in tools made from native plants and de-leafing of twigs never has been observed before. Both birds were observed using several of these tools to extract prey from under the bark of the native scalesia tree (Scalesia penduculta). They oriented the twigs such that the barbs pointed towards themselves; this rendered the barbs functional as they could be used to drag prey out of a crevice. The juvenile bird first watched the adult using the tool and then used the tool that the adult bird had left under the bark at the same location and in the same way as the adult. Our observation highlights the fact that opportunities for the transmission of social information do occur in the wild and indicates that woodpecker finches are flexible in their choice of tool material and tool modification. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Temporal variability and cooperative breeding: testing the bet-hedging hypothesis in the acorn woodpecker.

    Science.gov (United States)

    Koenig, Walter D; Walters, Eric L

    2015-10-07

    Cooperative breeding is generally considered an adaptation to ecological constraints on dispersal and independent breeding, usually due to limited breeding opportunities. Although benefits of cooperative breeding are typically thought of in terms of increased mean reproductive success, it has recently been proposed that this phenomenon may be a bet-hedging strategy that reduces variance in reproductive success (fecundity variance) in populations living in highly variable environments. We tested this hypothesis using long-term data on the polygynandrous acorn woodpecker (Melanerpes formicivorus). In general, fecundity variance decreased with increasing sociality, at least when controlling for annual variation in ecological conditions. Nonetheless, decreased fecundity variance was insufficient to compensate for reduced per capita reproductive success of larger, more social groups, which typically suffered lower estimated mean fitness. We did, however, find evidence that sociality in the form of larger group size resulted in increased fitness in years following a small acorn crop due to reduced fecundity variance. Bet-hedging, although not the factor driving sociality in general, may play a role in driving acorn woodpecker group living when acorns are scarce and ecological conditions are poor. © 2015 The Author(s).

  16. Biological Assessment of the Effects of the Proposed Revision of the 1996 Management Guidelines for the Red-cockaded Woodpecker on Army Installations

    National Research Council Canada - National Science Library

    Hayden, Timothy J

    2007-01-01

    In 1996, in an effort to meet conservation obligations under the Endangered Species Act, the Army revised earlier programmatic guidance for management of Red-cockaded Woodpeckers (RCW) on Army lands...

  17. Evaluating red-cockaded woodpeckers for exposure to West Nile Virus and blood parasites

    Science.gov (United States)

    Dusek, Robert J.; Richardson, D.; Egstad, Kristina F.; Heisey, Dennis M.

    2006-01-01

    A marked decline in the Picoides borealis (Red-cockaded Woodpecker [RCW]) population at Noxubee National Wildlife Refuge, MS, was observed in 2002. Demographic changes - including absence of hatch-year birds, decreases in size of known groups, and loss of known groups-were identified during annual fall surveys and are uncharacteristic of RCW populations. In 2003, a serosurvey of 28 adult RCWs was conducted to investigate the presence of West Nile virus (WNV) exposure in the population, possibly providing insight into whether WNV may have been responsible for this decline. Blood smears were also examined from these birds for blood parasites. We found no evidence of West Nile virus exposure or blood parasites in any of the RCWs sampled. Further monitoring of the RCW population and WNV activity in other species at Noxubee NWR is recommended to further evaluate the potential role of WNV and blood parasites in their decline.

  18. FUNGITOXICITY OF ESSENTIAL OILS ON PLASMOPARA VITICOLA,CAUSAL AGENT OF GRAPEVINE DOWNY MILDEW

    Directory of Open Access Journals (Sweden)

    RÉGIS DE OLIVEIRA FIALHO

    2017-10-01

    Full Text Available ABSTRACT This study aimed to evaluate the fungitoxic (antifungal effect of seven essential oils on Plasmopara viticola, the causal agent of grapevine downy mildew. The cinnamon, eucalyptus globulus, marjoram, melaleuca, peppermint, oregano and white thyme essential oils were compared with the mancozeb + metalaxyl-M fungicide. Three experiments were conducted to evaluate the effect of essential oils on spore germination. The first experiment evaluated the effect of direct contact of essential oils on the pathogen; the second evaluated the effect of volatile compounds on the pathogen and the third assessed the behavior of essential oils, when applied to vine leaves in field conditions, on the pathogen. All essential oils inhibited the spores’ germination, but in varying degrees, in addition, presenting fungistatic activity. All the essential oils showed chemical instability when the incubation time or the interval between products application where increased, all oils decrease antifungal activity percentage. Noteworthy, the cinnamon and the eucalyptus globulus essential oils were the most fungitoxic (antifungal on P. viticola.

  19. Nutritional improvement of the rose handling Peronospora Sparsa Berkeley, causal agent of downy mildew

    International Nuclear Information System (INIS)

    Castillo, Carlos Fernando; Alvarez, Elizabeth; Gomez, Eduardo; Llano, German; Castano Zapata, Jairo

    2010-01-01

    The downy mildew (Peronospora sparsa), is one of the most important diseases of rose in Colombia, causing losses up to 8%. The objective of this research was to determine a preventive control of the disease, through the improvement of the nutritional balance of the plant. The first phase, involved the effect of different concentrations of N, K, Ca, B and Mn, on the incidence and severity of the disease, and in the second one, the evaluation of the best five treatments of the first phase. The treatments were applied to the varieties Charlotte, Classy and Malibu during 4 weeks, using a splitting plot design with six replications. After one month the plants were inoculated with the fungus at a concentration of 3x104 sporangia mL. The results of the area under the disease progress curve (AUDPC), showed that the plants of Charlotte with 200 ppm of Si had the lowest expression of the disease. In Classy, the best treatment was the standard solution, demonstrating that the effects of the treatments depend of the variety. Charlotte and Malibu showed susceptibility, while Classy, partial resistance to the disease.

  20. Temperature effect on rose downy mildew development under environmental controlled conditions

    Directory of Open Access Journals (Sweden)

    Juan José Filgueira D.

    2014-04-01

    Full Text Available The rose downy mildew disease, caused by Peronospora sparsa Berkeley, is one of the most important that affect rose crops in Colombia. To manage this disease, flower growers must deal with high-costs due to the excessive application of fungicides, but without good results. Studies on P. sparsa behavior have shown its narrow relationship with environmental conditions. In this study, the temperature effect was evaluated during the infection and sporulation of P. sparsa in Charlotte leaflets, a susceptible commercial variety, through an environmental controlled conditions system. Infection and sporulation were observed at different temperatures in a range of from 4 to 40°C. Infection with the absence of or very low sporulation was observed at 4°C. The most favorable pathogen responses were between 15 and 18°C in terms of inoculum concentration and sporulation percentage. There was no infection or leaflet change above 35°C. According to the results, sporulation can occur from 4 to 33°C, confirming the fact that P. sparsa is able to reproduce throughout a wide temperature range.

  1. The ghost of outcrossing past in downy brome, an inbreeding annual grass.

    Science.gov (United States)

    Meyer, Susan E; Ghimire, Sudeep; Decker, Samuel; Merrill, Keith R; Coleman, Craig E

    2013-01-01

    We investigated the frequency of outcrossing in downy brome (Bromus tectorum L.), a cleistogamous weedy annual grass, in both common garden and wild populations, using microsatellite and single nucleotide polymorphic (SNP) markers. In the common garden study, 25 lines with strongly contrasting genotypes were planted in close proximity. We fingerprinted 10 seed progeny from 8 individuals of each line and detected 15 first-generation heterozygotes for a t-value (corrected for cryptic crosses) of 0.0082. Different genotypes were significantly overrepresented as maternal versus paternal parents of heterozygotes, suggesting gender-function-dependent genetic control of outcrossing rates. In 4 wild populations (>300 individuals each), expected heterozygosity ranged from 0.149 to 0.336, whereas t-values ranged from 0.0027 to 0.0133, indicating high levels of both genetic diversity and inbreeding. Up to a third of the individuals in each population belonged to groups with identical or nearly identical SNP genotypes, whereas many of the remaining individuals were members of loose clusters of apparently related plants that probably represent descendants from past outcrossing events. Strict inbreeding in some lineages within a population with occasional outcrossing in others may be related to positive selection on adaptive syndromes associated with specific inbreeding lineages, or possibly to among-lineage differences in genetic regulation of outcrossing.

  2. Control of litchi downy blight by zeamines produced by Dickeya zeae.

    Science.gov (United States)

    Liao, Lisheng; Zhou, Jianuan; Wang, Huishan; He, Fei; Liu, Shiyin; Jiang, Zide; Chen, Shaohua; Zhang, Lian-Hui

    2015-10-26

    Zeamines (ZMS), a class of polyamine-polyketide-nonribosomal peptide produced by bacterial isolate Dickeya zeae, were shown recently to be potent antibiotics against some bacterial pathogens. In this study, the results indicated that ZMS showed antifungal activity against Peronophythora litchii and other fungal pathogens. The activity of ZMS against the oomycete pathogen P. litchi, which causes the devastating litchi downy blight, was further investigated under in vitro and in vivo conditions. ZMS displayed potent inhibitory activity against the mycelial growth and sporangia germination of P. litchii. At a concentration of 2 μg/mL, about 99% of the sporangia germination was inhibited. Scanning electron microscopy and transmission electron microscopy analyses showed that treatment with ZMS could cause substantial damages to the oomycete endomembrane system. Furthermore, treatment of litchi fruits with ZMS solution significantly (P < 0.05) reduced the fruits decay and peel browning caused by P. litchii infection during storage at 28 °C. Taken together, our results provide useful clues on the antifungal mechanisms of ZMS, and highlight the promising potentials of ZMS as a fungicide, which in particular, may be useful for prevention and control of litchi fruits decay and browning caused by P. litchii infection during storage and transportation.

  3. Concordant genetic structure in two species of woodpecker distributed across the primary West African biogeographic barriers.

    Science.gov (United States)

    Fuchs, Jérôme; Bowie, Rauri C K

    2015-07-01

    The lowland forests of western and central tropical Africa are separated by several potential biogeographic barriers to dispersal for forest adapted vertebrates. The two primary barriers are (1) the Dahomey Gap, a savanna corridor that reaches the coast of southern Ghana, Togo and Benin, and separates the West African rainforest into the Upper (Ghana west to Guinea) and Lower Guinea (Nigeria to Uganda and Angola) forest blocks, and (2) the Lower Niger River, a large delta that separates Western and Eastern Nigeria. Previous studies on terrestrial vertebrates (lizards, mammals and birds) have highlighted a genetic break in the Dahomey Gap/Lower Niger River area although the relative importance of each barrier has not been assessed due to limitations in geographic sampling. We compared the phylogeographic history of two co-distributed sister-species of woodpeckers (Campethera caroli and C. nivosa) using data from three loci representing all inheritance modes. Our analyses revealed that both the Dahomey Gap and possibly the Lower Niger River acted as strong biogeographic barriers for the two woodpecker species, with the Lower Niger River being the first barrier to have formed, leading to three distinct populations of C. nivosa. Our divergence time analyses revealed that both these biogeographic barriers formed during the Pleistocene, supporting the Pleistocene refuge hypothesis, with the Dahomey Gap likely appearing about 0.5 myr BP. No genetic structure was recovered among sampled populations in either the Upper or the Lower Guinea Forest Block for both species, despite the considerable geographic area covered. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Ecological Risk Assessment of the Effects of Military Fog Oil Obscurant Smoke on the Red-cockaded Woodpecker

    Science.gov (United States)

    2005-01-01

    possible that any observed reductions in biomass are caused by a disruption of the symbiotic fungal endophyte associations that many perennial grasses...support. Unfortunately, no data are available on the effects of fog oil on soil fungi . Microbial Effects From a taxonomic and apparently...Stephen F. Austin State University, Nacogdoches, TX. . Conner, R.N. and B.A. Locke. 1982. Fungi and Red-cockaded Woodpecker cavity trees. Wilson

  5. Phenotypic and molecular characterization of 18 Bulgarian newly bred grapevine varieties in relation to their resistance to downy mildew

    Directory of Open Access Journals (Sweden)

    Kalin Kosev

    2017-01-01

    Full Text Available Eighteen Bulgarian newly bred grapevine varieties obtained by interspecific crossing were analysed through microsatellite markers in order to determine their genetic identity as well as the presence of resistance-related alleles linked to Rpv3, Rpv10 and Rpv12 loci. The levels of resistance of the investigated cultivars to downy mildew were assessed by leaf disk assay and were scored according to OIV descriptor 452. Seven isolates of Plasmopara viticola collected in different regions of Bulgaria were characterized and discriminated with seven microsatellite markers and were used in the assays. Analysis of variance showed significant differences in resistance to downy mildew among the analysed varieties. A clear correlation between the presence of particular Rpvs and the level of resistance was determined. Five cultivars, ‘Droujba’, ‘Garant’ and ‘Plevenska rosa’ harbouring Rpv3 and Rpv12, ‘Kajlashki rubin’ harbouring Rpv12 and ‘Slava’, Rpv10 and Rpv3, showed high level of resistance with mean OIV452 values ranging from 6.5 to 8.25 over all seven P. viticola isolates. The level of resistance of the remaining 14 cultivars, which carry only Rpv3 inherited from cultivar Villard Blanc, was found to vary significantly among the isolates with mean OIV452 values between 1.75 and 4.8 over all used P. viticola isolates. The results obtained in this study favoured five genotypes remarkable for their high resistance to downy mildew and very good quality of grape and wine. These varieties represent a valuable material for pyramiding of resistance through marker-assisted selection.

  6. Pl(17) is a novel gene independent of known downy mildew resistance genes in the cultivated sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Qi, L L; Long, Y M; Jan, C C; Ma, G J; Gulya, T J

    2015-04-01

    Pl 17, a novel downy mildew resistance gene independent of known downy mildew resistance genes in sunflowers, was genetically mapped to linkage group 4 of the sunflower genome. Downy mildew (DM), caused by Plasmopara halstedii (Farl.). Berl. et de Toni, is one of the serious sunflower diseases in the world due to its high virulence and the variability of the pathogen. DM resistance in the USDA inbred line, HA 458, has been shown to be effective against all virulent races of P. halstedii currently identified in the USA. To determine the chromosomal location of this resistance, 186 F 2:3 families derived from a cross of HA 458 with HA 234 were phenotyped for their resistance to race 734 of P. halstedii. The segregation ratio of the population supported that the resistance was controlled by a single dominant gene, Pl 17. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) primers were used to identify molecular markers linked to Pl 17. Bulked segregant analysis using 849 SSR markers located Pl 17 to linkage group (LG) 4, which is the first DM gene discovered in this linkage group. An F2 population of 186 individuals was screened with polymorphic SSR and SNP primers from LG4. Two flanking markers, SNP SFW04052 and SSR ORS963, delineated Pl 17 in an interval of 3.0 cM. The markers linked to Pl 17 were validated in a BC3 population. A search for the physical location of flanking markers in sunflower genome sequences revealed that the Pl 17 region had a recombination frequency of 0.59 Mb/cM, which was a fourfold higher recombination rate relative to the genomic average. This region can be considered amenable to molecular manipulation for further map-based cloning of Pl 17.

  7. Effect of Pseudomonas spp on infection of Peronosporaparasitica (Pers. Fr), the pathogen of downy mildew on Chinese cabbage

    Science.gov (United States)

    Damiri, N.; Mulawarman; Umayah, A.; Agustin, S. E.; Rahmiyah, M.

    2018-01-01

    This research was conducted to study the effect of the application of Pseudomonasspp on infection of Peronosporaparasitica (Pers. Fr), the pathogen of Downy mildew on Chinese cabbage. The research was conducted in the laboratory and greenhouse Department of Plant Pests and Diseases Faculty of Agriculture Sriwijaya University, Inderalaya, OganIlir South Sumatra Indonesia. The research was conducted in the laboratory and greenhouse Department of Plant Pests and Diseases Faculty of Agriculture Sriwijaya University, Inderalaya, Ogan Ilir South Sumatra Indonesia. The research was conducted using Completely Randomized Design with ten treatments including control. ie: isolate A, Isolate B, isolate C, isolate D, isolate E, isolate F, isolate G, isolate H, isolate I and control. Each treatment consists of four replications. Results of the study showed that the application of Pseudomonas spp. can suppress the infection of P. parasitica on Chinese cabbage. The lowest disease intensity was shown by treatment C (isolate Pseudomonas sp.) which was significantly different from control. The best treatment in suppressing disease severity of downy mildew on chinese cabbage was isolate H which had disease severity of 37.07 percent, which was significantly different from control and other treatment.

  8. Comparison of Red-Cockaded Woodpecker (Piciodes borealis) Nestling Diet in Old-Growth and Old-Field Longleaf Pine (Pinus palustris)

    Energy Technology Data Exchange (ETDEWEB)

    Hanula, J.L.; Engstrom, R.T.

    1999-10-01

    Automatic cameras were used to record adult woodpecker diets in old-growth and old-field longleaf pine in the South. Roaches were the number one prey for the woodpeckers based on either biomass or numbers. The latter ranged from 37% to 57% of the prey numbers and 55%-73% of the biomass. Morisita's index of similarity between old-field and old growth varied from 0.89 to 0.95. The authors conclude that the prey base is similar in both conditions and that old-growth provides similar foraging habitat.

  9. Historical introgression of the downy mildew resistance gene Rpv12 from the Asian species Vitis amurensis into grapevine varieties.

    Directory of Open Access Journals (Sweden)

    Silvia Venuti

    Full Text Available The Amur grape (Vitis amurensis Rupr. thrives naturally in cool climates of Northeast Asia. Resistance against the introduced pathogen Plasmopara viticola is common among wild ecotypes that were propagated from Manchuria into Chinese vineyards or collected by Soviet botanists in Siberia, and used for the introgression of resistance into wine grapes (Vitis vinifera L.. A QTL analysis revealed a dominant gene Rpv12 that explained 79% of the phenotypic variance for downy mildew resistance and was inherited independently of other resistance genes. A Mendelian component of resistance-a hypersensitive response in leaves challenged with P. viticola-was mapped in an interval of 0.2 cM containing an array of coiled-coil NB-LRR genes on chromosome 14. We sequenced 10-kb genic regions in the Rpv12(+ haplotype and identified polymorphisms in 12 varieties of V. vinifera using next-generation sequencing. The combination of two SNPs in single-copy genes flanking the NB-LRR cluster distinguished the resistant haplotype from all others found in 200 accessions of V. vinifera, V. amurensis, and V. amurensis x V. vinifera crosses. The Rpv12(+ haplotype is shared by 15 varieties, the most ancestral of which are the century-old 'Zarja severa' and 'Michurinets'. Before this knowledge, the chromosome segment around Rpv12(+ became introgressed, shortened, and pyramided with another downy mildew resistance gene from North American grapevines (Rpv3 only by phenotypic selection. Rpv12(+ has an additive effect with Rpv3(+ to protect vines against natural infections, and confers foliar resistance to strains that are virulent on Rpv3(+ plants.

  10. Resistance to Downy Mildew in Lettuce 'La Brillante' is Conferred by Dm50 Gene and Multiple QTL.

    Science.gov (United States)

    Simko, Ivan; Ochoa, Oswaldo E; Pel, Mathieu A; Tsuchida, Cayla; Font I Forcada, Carolina; Hayes, Ryan J; Truco, Maria-Jose; Antonise, Rudie; Galeano, Carlos H; Michelmore, Richard W

    2015-09-01

    Many cultivars of lettuce (Lactuca sativa L.) are susceptible to downy mildew, a nearly globally ubiquitous disease caused by Bremia lactucae. We previously determined that Batavia type cultivar 'La Brillante' has a high level of field resistance to the disease in California. Testing of a mapping population developed from a cross between 'Salinas 88' and La Brillante in multiple field and laboratory experiments revealed that at least five loci conferred resistance in La Brillante. The presence of a new dominant resistance gene (designated Dm50) that confers complete resistance to specific isolates was detected in laboratory tests of seedlings inoculated with multiple diverse isolates. Dm50 is located in the major resistance cluster on linkage group 2 that contains at least eight major, dominant Dm genes conferring resistance to downy mildew. However, this Dm gene is ineffective against the isolates of B. lactucae prevalent in the field in California and the Netherlands. A quantitative trait locus (QTL) located at the Dm50 chromosomal region (qDM2.2) was detected, though, when the amount of disease was evaluated a month before plants reached harvest maturity. Four additional QTL for resistance to B. lactucae were identified on linkage groups 4 (qDM4.1 and qDM4.2), 7 (qDM7.1), and 9 (qDM9.2). The largest effect was associated with qDM7.1 (up to 32.9% of the total phenotypic variance) that determined resistance in multiple field experiments. Markers identified in the present study will facilitate introduction of these resistance loci into commercial cultivars of lettuce.

  11. Habitat selection and reproductive success of Lewis's Woodpecker (Melanerpes lewis at its northern limit.

    Directory of Open Access Journals (Sweden)

    Xiang Zhu

    Full Text Available Lewis's Woodpecker (Melanerpes lewis has experienced population declines in both Canada and the United States and in 2010 was assigned a national listing of threatened in Canada. We conducted a two-year study (2004-2005 of this species at its northern range limit, the South Okanagan Valley in British Columbia, Canada. Our main objective was to determine whether the habitat features that influenced nest-site selection also predicted nest success, or whether other factors (e.g. cavity dimensions, clutch initiation date or time of season were more important. Nest tree decay class, density of suitable cavities and total basal area of large trees were the best predictors of nest-site selection, but these factors were unrelated to nesting success. Estimates of demographic parameters (mean ± SE included daily nest survival rate (0.988±0.003, years combined, nest success (0.52±0.08, clutch size (5.00±0.14 eggs, female fledglings per successful nest (1.31±0.11, and annual productivity (0.68±0.12 female fledglings per nest per year. Although higher nest survival was associated with both early and late initiated clutches, early-initiated clutches allowed birds to gain the highest annual productivity as early clutches were larger. Nests in deep cavities with small entrances experienced lower predation risk especially during the peak period of nest predation. We concluded that nest-site selection can be predicted by a number of easily measured habitat variables, whereas nest success depended on complicated ecological interactions among nest predators, breeding behaviors, and cavity features. Thus, habitat-based conservation strategies should also consider ecological factors that may not be well predicted by habitat.

  12. Doses of ash from carbonized rice husk on the incidence and damage of thrips, downy mildew severity and yield of onion under organic system

    Directory of Open Access Journals (Sweden)

    Paulo Antonio de Souza Gonçalves

    2017-10-01

    Full Text Available The objective of this study was to evaluate the effect of ash from carbonized rice husk on the incidence and damage of thrips, downy mildew severity, yield, onion postharvest performance and chemical characteristics of the soil in organic system. The study was conducted in the field at Epagri, Experimental Station of Ituporanga, Santa Catarina State, Brazil. The cultivar used was Epagri 362 Crioula Alto Vale. The treatments were doses of carbonized rice husk ash 5 t ha-1, 10 t ha-1, 15 t ha-1 and untreated check. Randomized blocks design with five replications was used. The treatments do not affect the incidence and damage of thrips, downy mildew severity, leaf potassium content, yield and onion postharvest yield. Doses of ash influence the content of potassium in the soil in a positive quadratic relation and does not change the pH, organic matter, P, Ca, Al, Mg, and Na.

  13. Alternatives to copper-based treatments for the control of grapevine downy mildew (Plasmopara viticola): 5-year synthesis of trials in France and Italy

    OpenAIRE

    Parveaud, Claude-Eric; Gomez, Christelle; Chovelon, Marc; Lambion, Jérôme; Dagostin, Silvia; Pertot, Ilaria

    2010-01-01

    The objective of the UE-funded program REPCO (FP6) was to identify new alternatives to copper fungicides in organic farming. Two pathogens have been considered: grapevine downy mildew (Plasmopara viticola) and apple scab (Venturia inaequalis). Research on grapevine was carried out by GRAB (Avignon, France) and FEM-IASMA (San Michele all’Adige, Italy). Trials were carried out under natural conditions in order to test reduced doses of copper and copper-free alternatives. Five-year trials proved...

  14. Optimisation of downy mildew (Plasmopara viticola) control in organic viticulture with low copper doses, new copper formulations and plant strengtheners, results of four years of on farm research

    OpenAIRE

    Hofmann, U.; Heibertshausen, D.; Baus-Reichel, O.; Berkelmann-Loehnertz, B.

    2008-01-01

    In three different wine growing regions in Germany, due to weather and infection conditions several fungicide (copper formulations) and plant strengtheners (Myco-Sin VIN®, Kendal®, Frutogard ®) applications against downy mildew are required in order to obtain satisfactory disease control. Results of the four years of on farm trials confirmed good efficacy of the copper based substances like copper hydroxide, partly in combination with two or three applications of potassium phosphonate, new co...

  15. Molecular detection of Peronospora variabilis in quinoa seeds and phylogeny of the quinoa downy mildew pathogen in South America and the United States

    OpenAIRE

    Testen, Anna L.; M. Jimenez-Gasco; Ochoa, J.B.; Backman, Paul A.

    2014-01-01

    Metadata only record As Quinoa production increases in response to growing global demand for the crop, it is necessary to develop improved production practices that will support sustainable production. To that end, this paper examines the ability of the Bacillus species of bacteria to colonize quinoa and to promote quinoa growth, and seeks to identify source of inoculum for Peronospora variabilis, the cause of the quinoa downy mildow disease. Bacillus populations isolated from Pennsylvania...

  16. Molecular detection of Peronospora variabilis in quinoa seed and phylogeny of the quinoa downy mildew pathogen in South America and the United States.

    Science.gov (United States)

    Testen, Anna L; del Mar Jiménez-Gasco, María; Ochoa, José B; Backman, Paul A

    2014-04-01

    Quinoa (Chenopodium quinoa) is an important export of the Andean region, and its key disease is quinoa downy mildew, caused by Peronospora variabilis. P. variabilis oospores can be seedborne and rapid methods to detect seedborne P. variabilis have not been developed. In this research, a polymerase chain reaction (PCR)-based detection method was developed to detect seedborne P. variabilis and a sequencing-based method was used to validate the PCR-based method. P. variabilis was detected in 31 of 33 quinoa seed lots using the PCR-based method and in 32 of 33 quinoa seed lots using the sequencing-based method. Thirty-one of the quinoa seed lots tested in this study were sold for human consumption, with seed originating from six different countries. Internal transcribed spacer (ITS) and cytochrome c oxidase subunit 2 (COX2) phylogenies were examined to determine whether geographical differences occurred in P. variabilis populations originating from Ecuador, Bolivia, and the United States. No geographical differences were observed in the ITS-derived phylogeny but the COX2 phylogeny indicated that geographical differences existed between U.S. and South American samples. Both ITS and COX2 phylogenies supported the existence of a Peronospora sp., distinct from P. variabilis, that causes systemic-like downy mildew symptoms on quinoa in Ecuador. The results of these studies allow for a better understanding of P. variabilis populations in South America and identified a new causal agent for quinoa downy mildew. The PCR-based seed detection method allows for the development of P. variabilis-free quinoa seed, which may prove important for management of quinoa downy mildew.

  17. Genotyping-by-sequencing targeting of a novel downy mildew resistance gene Pl 20 from wild Helianthus argophyllus for sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Ma, G J; Markell, S G; Song, Q J; Qi, L L

    2017-07-01

    Genotyping-by-sequencing revealed a new downy mildew resistance gene, Pl 20 , from wild Helianthus argophyllus located on linkage group 8 of the sunflower genome and closely linked to SNP markers that facilitate the marker-assisted selection of resistance genes. Downy mildew (DM), caused by Plasmopara halstedii, is one of the most devastating and yield-limiting diseases of sunflower. Downy mildew resistance identified in wild Helianthus argophyllus accession PI 494578 was determined to be effective against the predominant and virulent races of P. halstedii occurring in the United States. The evaluation of 114 BC 1 F 2:3 families derived from the cross between HA 89 and PI 494578 against P. halstedii race 734 revealed that single dominant gene controls downy mildew resistance in the population. Genotyping-by-sequencing analysis conducted in the BC 1 F 2 population indicated that the DM resistance gene derived from wild H. argophyllus PI 494578 is located on the upper end of the linkage group (LG) 8 of the sunflower genome, as was determined single nucleotide polymorphism (SNP) markers associated with DM resistance. Analysis of 11 additional SNP markers previously mapped to this region revealed that the resistance gene, named Pl 20 , co-segregated with four markers, SFW02745, SFW09076, S8_11272025, and S8_11272046, and is flanked by SFW04358 and S8_100385559 at an interval of 1.8 cM. The newly discovered P. halstedii resistance gene has been introgressed from wild species into cultivated sunflower to provide a novel gene with DM resistance. The homozygous resistant individuals were selected from BC 2 F 2 progenies with the use of markers linked to the Pl 20 gene, and these lines should benefit the sunflower community for Helianthus improvement.

  18. Genetics and mapping of a novel downy mildew resistance gene, Pl(18), introgressed from wild Helianthus argophyllus into cultivated sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Qi, L L; Foley, M E; Cai, X W; Gulya, T J

    2016-04-01

    A novel downy mildew resistance gene, Pl(18), was introgressed from wild Helianthus argophyllus into cultivated sunflower and genetically mapped to linkage group 2 of the sunflower genome. The new germplasm, HA-DM1, carrying Pl(18) has been released to the public. Sunflower downy mildew (DM) is considered to be the most destructive foliar disease that has spread to every major sunflower-growing country of the world, except Australia. A new dominant downy mildew resistance gene (Pl 18) transferred from wild Helianthus argophyllus (PI 494573) into cultivated sunflower was mapped to linkage group (LG) 2 of the sunflower genome using bulked segregant analysis with 869 simple sequence repeat (SSR) markers. Phenotyping 142 BC1F2:3 families derived from the cross of HA 89 and H. argophyllus confirmed the single gene inheritance of resistance. Since no other Pl gene has been mapped to LG2, this gene was novel and designated as Pl (18). SSR markers CRT214 and ORS203 flanked Pl(18) at a genetic distance of 1.1 and 0.4 cM, respectively. Forty-six single nucleotide polymorphism (SNP) markers that cover the Pl(18) region were surveyed for saturation mapping of the region. Six co-segregating SNP markers were 1.2 cM distal to Pl(18), and another four co-segregating SNP markers were 0.9 cM proximal to Pl(18). The new BC2F4-derived germplasm, HA-DM1, carrying Pl(18) has been released to the public. This new line is highly resistant to all Plasmopara halstedii races identified in the USA providing breeders with an effective new source of resistance against downy mildew in sunflower. The molecular markers that were developed will be especially useful in marker-assisted selection and pyramiding of Pl resistance genes because of their close proximity to the gene and the availability of high-throughput SNP detection assays.

  19. Discovery and introgression of the wild sunflower-derived novel downy mildew resistance gene Pl 19 in confection sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Zhang, Z W; Ma, G J; Zhao, J; Markell, S G; Qi, L L

    2017-01-01

    A new downy mildew resistance gene, Pl 19 , was identified from wild Helianthus annuus accession PI 435414, introduced to confection sunflower, and genetically mapped to linkage group 4 of the sunflower genome. Wild Helianthus annuus accession PI 435414 exhibited resistance to downy mildew, which is one of the most destructive diseases to sunflower production globally. Evaluation of the 140 BC 1 F 2:3 families derived from the cross of CMS CONFSCLB1 and PI 435414 against Plasmopara halstedii race 734 revealed that a single dominant gene controls downy mildew resistance in the population. Bulked segregant analysis conducted in the BC 1 F 2 population with 860 simple sequence repeat (SSR) markers indicated that the resistance derived from wild H. annuus was associated with SSR markers located on linkage group (LG) 4 of the sunflower genome. To map and tag this resistance locus, designated Pl 19 , 140 BC 1 F 2 individuals were used to construct a linkage map of the gene region. Two SSR markers, ORS963 and HT298, were linked to Pl 19 within a distance of 4.7 cM. After screening 27 additional single nucleotide polymorphism (SNP) markers previously mapped to this region, two flanking SNP markers, NSA_003564 and NSA_006089, were identified as surrounding the Pl 19 gene at a distance of 0.6 cM from each side. Genetic analysis indicated that Pl 19 is different from Pl 17 , which had previously been mapped to LG4, but is closely linked to Pl 17 . This new gene is highly effective against the most predominant and virulent races of P. halstedii currently identified in North America and is the first downy mildew resistance gene that has been transferred to confection sunflower. The selected resistant germplasm derived from homozygous BC 2 F 3 progeny provides a novel gene for use in confection sunflower breeding programs.

  20. Identification and characterization of potential NBS-encoding resistance genes and induction kinetics of a putative candidate gene associated with downy mildew resistance in Cucumis

    Directory of Open Access Journals (Sweden)

    Wan Hongjian

    2010-08-01

    Full Text Available Abstract Background Due to the variation and mutation of the races of Pseudoperonospora cubensis, downy mildew has in recent years become the most devastating leaf disease of cucumber worldwide. Novel resistance to downy mildew has been identified in the wild Cucumis species, C. hystrix Chakr. After the successful hybridization between C. hystrix and cultivated cucumber (C. sativus L., an introgression line (IL5211S was identified as highly resistant to downy mildew. Nucleotide-binding site and leucine-rich repeat (NBS-LRR genes are the largest class of disease resistance genes cloned from plant with highly conserved domains, which can be used to facilitate the isolation of candidate genes associated with downy mildew resistance in IL5211S. Results Degenerate primers that were designed based on the conserved motifs in the NBS domain of resistance (R proteins were used to isolate NBS-type sequences from IL5211S. A total of 28 sequences were identified and named as cucumber (C. sativus = CS resistance gene analogs as CSRGAs. Polygenetic analyses separated these sequences into four different classes. Quantitative real-time polymerase chain reaction (qRT-PCR analysis showed that these CSRGAs expressed at different levels in leaves, roots, and stems. In addition, introgression from C. hystrix induced expression of the partial CSRGAs in cultivated cucumber, especially CSRGA23, increased four-fold when compared to the backcross parent CC3. Furthermore, the expression of CSRGA23 under P. cubensis infection and abiotic stresses was also analyzed at different time points. Results showed that the P. cubensis treatment and four tested abiotic stimuli, MeJA, SA, ABA, and H2O2, triggered a significant induction of CSRGA23 within 72 h of inoculation. The results indicate that CSRGA23 may play a critical role in protecting cucumber against P. cubensis through a signaling the pathway triggered by these molecules. Conclusions Four classes of NBS-type RGAs were

  1. QTL mapping for downy mildew resistance in cucumber via bulked segregant analysis using next-generation sequencing and conventional methods.

    Science.gov (United States)

    Win, Khin Thanda; Vegas, Juan; Zhang, Chunying; Song, Kihwan; Lee, Sanghyeob

    2017-01-01

    QTL mapping using NGS-assisted BSA was successfully applied to an F 2 population for downy mildew resistance in cucumber. QTLs detected by NGS-assisted BSA were confirmed by conventional QTL analysis. Downy mildew (DM), caused by Pseudoperonospora cubensis, is one of the most destructive foliar diseases in cucumber. QTL mapping is a fundamental approach for understanding the genetic inheritance of DM resistance in cucumber. Recently, many studies have reported that a combination of bulked segregant analysis (BSA) and next-generation sequencing (NGS) can be a rapid and cost-effective way of mapping QTLs. In this study, we applied NGS-assisted BSA to QTL mapping of DM resistance in cucumber and confirmed the results by conventional QTL analysis. By sequencing two DNA pools each consisting of ten individuals showing high resistance and susceptibility to DM from a F 2 population, we identified single nucleotide polymorphisms (SNPs) between the two pools. We employed a statistical method for QTL mapping based on these SNPs. Five QTLs, dm2.2, dm4.1, dm5.1, dm5.2, and dm6.1, were detected and dm2.2 showed the largest effect on DM resistance. Conventional QTL analysis using the F 2 confirmed dm2.2 (R 2  = 10.8-24 %) and dm5.2 (R 2  = 14-27.2 %) as major QTLs and dm4.1 (R 2  = 8 %) as two minor QTLs, but could not detect dm5.1 and dm6.1. A new QTL on chromosome 2, dm2.1 (R 2  = 28.2 %) was detected by the conventional QTL method using an F 3 population. This study demonstrated the effectiveness of NGS-assisted BSA for mapping QTLs conferring DM resistance in cucumber and revealed the unique genetic inheritance of DM resistance in this population through two distinct major QTLs on chromosome 2 that mainly harbor DM resistance.

  2. Habitat quantity of Red-cockaded Woodpecker Picoides borealis (Aves: Piciformes: Picidae in its former historic landscape near the Big Thicket National Preserve, Texas, USA

    Directory of Open Access Journals (Sweden)

    Vivek Thapa

    2016-01-01

    Full Text Available We quantified pine-forested habitat suitable for Red-cockaded Woodpecker Picoides borealis in the former historic range of the species to assess the potential for possible re-colonization.  We used a remotely-sensed image and geographic information systems (GIS to create a land-use/land (LU/LC binary cover map, from which we calculated the habitat suitability index (HSI based on an estimated home range of 50ha.  A sensitivity analysis revealed the necessity for more data to make an accurate estimate, but our analysis of landscape metrics indicates more than 930ha of suitable habitat patches.  These patches are heavily fragmented and mostly located on private lands.  They can be assessed for understory and herbaceous vegetation and can be restored for possible re-establishment of approximately 18 groups/colonies of Red-cockaded Woodpeckers

  3. Specimen-based modeling, stopping rules, and the extinction of the Ivory-Billed Woodpecker

    DEFF Research Database (Denmark)

    Gotelli, Nicholas J.; Chao, Anne; Colwell, Robert K.

    2012-01-01

    Assessing species survival status is an essential component of conservation programs. We devised a new statistical method for estimating the probability of species persistence from the temporal sequence of collection dates of museum specimens. To complement this approach, we developed quantitative...... (Campephilus principalis), long assumed to have become extinct in the United States in the 1950s, but reportedly rediscovered in 2004. We analyzed the temporal pattern of the collection dates of 239 geo-referenced museum specimens collected throughout the southeastern United States from 1853 to 1932...

  4. Enhancement of downy mildew disease resistance in pearl millet by the G_app7 bioactive compound produced by Ganoderma applanatum.

    Science.gov (United States)

    Jogaiah, Sudisha; Shetty, Hunthrike Shekar; Ito, Shin-Ichi; Tran, Lam-Son Phan

    2016-08-01

    Pearl millet (Pennisetum glaucum) stands sixth among the most important cereal crops grown in the semi-arid and arid regions of the world. The downy mildew disease caused by Sclerospora graminicola, an oomycete pathogen, has been recognized as a major biotic constraint in pearl millet production. On the other hand, basidiomycetes are known to produce a large number of antimicrobial metabolites, providing a good source of anti-oomycete agrochemicals. Here, we report the discovery and efficacy of a compound, named G_app7, purified from Ganoderma applanatum on inhibition of growth and development of S. graminicola, as well as the effects of seed treatment with G_app7 on protection of pearl millet from downy mildew. G_app7 consistently demonstrated remarkable effects against S. graminicola by recording significant inhibition of sporangium formation (41.4%), zoospore release (77.5%) and zoospore motility (91%). Analyses of G_app7 compound using two-dimensional nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry revealed its close resemblance to metominostrobin, a derivative of strobilurin group of fungicides. Furthermore, the G_app7 was shown to stably maintain the inhibitory effects at different temperatures between 25 and 80 °C. In addition, the anti-oomycete activity of G_app7 was fairly stable for a period of at least 12 months at 4 °C and was only completely lost after being autoclaved. Seed treatment with G_app7 resulted in a significant increase in disease protection (63%) under greenhouse conditions compared with water control. The identification and isolation of this novel and functional anti-oomycete compound from G. applanatum provide a considerable agrochemical importance for plant protection against downy mildew in an environmentally safe and economical manner. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Proteomic analysis of elicitation of downy mildew disease resistance in pearl millet by seed priming with β-aminobutyric acid and Pseudomonas fluorescens.

    Science.gov (United States)

    Anup, Chandra Pal; Melvin, Prasad; Shilpa, Nataraj; Gandhi, Mayuri Nalin; Jadhav, Manali; Ali, Hussain; Kini, Kukkundoor Ramachandra

    2015-04-29

    Downy mildew is one of the severe diseases of pearl millet, globally affecting its commercial production. Priming of seeds of a susceptible cultivar of pearl millet with β-aminobutyric acid (BABA) and Pseudomonas fluorescens has reduced the downy mildew disease incidence level under field studies. In the current study, proteomic approach was used to elucidate the poorly studied resistance mechanism in these elicitor primed pearl millet seeds in response to Sclerospora graminicola infection. 2DE-MS/MS based proteomic approach revealed that majority of the 63 differentially accumulated (p≤0.05) proteins associated with energy and metabolism followed by stress and defense category. Multivariate statistics disclosed that infection caused by the pathogen rather than elicitor treatment had a major influence on the dynamics of protein abundance. Mechanism of priming mediated by BABA and P. fluorescens were different from each other as evident by the protein abundance profile of hierarchical clustering analysis. Over-representation of proteins pertaining to glucose metabolism suggests that seed priming ensures plant protection against disease without compromising its normal growth and development. In addition the study forms a basis for future investigation by functional analysis of these differentially accumulated proteins to further unravel the resistance mechanism of elicitor primed plant against the S. graminicola. The study is based on the comparative proteomic analysis between BABA and P. fluorescens mediated resistance in pearl millet, in response to downy mildew causing biotroph - S. graminicola. To our knowledge, this article is the first to report on seedling proteome of pearl millet whose genome is not yet sequenced. In addition, the study also provides clue for the plausible antagonistic cross-talk that might exist between jasmonic acid signaling and salicylic acid signaling in SAR and ISR mediated resistance by BABA and P. fluorescens against the downy

  6. Expression Profiling during Arabidopsis/Downy Mildew Interaction Reveals a Highly-Expressed Effector That Attenuates Responses to Salicylic Acid

    Science.gov (United States)

    Asai, Shuta; Caillaud, Marie-Cécile; Furzer, Oliver J.; Ishaque, Naveed; Wirthmueller, Lennart; Fabro, Georgina; Shirasu, Ken; Jones, Jonathan D. G.

    2014-01-01

    Plants have evolved strong innate immunity mechanisms, but successful pathogens evade or suppress plant immunity via effectors delivered into the plant cell. Hyaloperonospora arabidopsidis (Hpa) causes downy mildew on Arabidopsis thaliana, and a genome sequence is available for isolate Emoy2. Here, we exploit the availability of genome sequences for Hpa and Arabidopsis to measure gene-expression changes in both Hpa and Arabidopsis simultaneously during infection. Using a high-throughput cDNA tag sequencing method, we reveal expression patterns of Hpa predicted effectors and Arabidopsis genes in compatible and incompatible interactions, and promoter elements associated with Hpa genes expressed during infection. By resequencing Hpa isolate Waco9, we found it evades Arabidopsis resistance gene RPP1 through deletion of the cognate recognized effector ATR1. Arabidopsis salicylic acid (SA)-responsive genes including PR1 were activated not only at early time points in the incompatible interaction but also at late time points in the compatible interaction. By histochemical analysis, we found that Hpa suppresses SA-inducible PR1 expression, specifically in the haustoriated cells into which host-translocated effectors are delivered, but not in non-haustoriated adjacent cells. Finally, we found a highly-expressed Hpa effector candidate that suppresses responsiveness to SA. As this approach can be easily applied to host-pathogen interactions for which both host and pathogen genome sequences are available, this work opens the door towards transcriptome studies in infection biology that should help unravel pathogen infection strategies and the mechanisms by which host defense responses are overcome. PMID:25329884

  7. Over-expression of VvWRKY1 in grapevines induces expression of jasmonic acid pathway-related genes and confers higher tolerance to the downy mildew.

    Directory of Open Access Journals (Sweden)

    Chloé Marchive

    Full Text Available Most WRKY transcription factors activate expression of defence genes in a salicylic acid- and/or jasmonic acid-dependent signalling pathway. We previously identified a WRKY gene, VvWRKY1, which is able to enhance tolerance to fungal pathogens when it is overexpressed in tobacco. The present work analyzes the effects of VvWRKY1 overexpression in grapevine. Microarray analysis showed that genes encoding defence-related proteins were up-regulated in the leaves of transgenic 35S::VvWRKY1 grapevines. Quantitative RT-PCR analysis confirmed that three genes putatively involved in jasmonic acid signalling pathway were overexpressed in the transgenic grapes. The ability of VvWRKY1 to trans-activate the promoters of these genes was demonstrated by transient expression in grape protoplasts. The resistance to the causal agent of downy mildew, Plasmopara viticola, was enhanced in the transgenic plants. These results show that VvWRKY1 can increase resistance of grapevine against the downy mildew through transcriptional reprogramming leading to activation of the jasmonic acid signalling pathway.

  8. RXLR and CRN Effectors from the Sunflower Downy Mildew Pathogen Plasmopara halstedii Induce Hypersensitive-Like Responses in Resistant Sunflower Lines

    Science.gov (United States)

    Gascuel, Quentin; Buendia, Luis; Pecrix, Yann; Blanchet, Nicolas; Muños, Stéphane; Vear, Felicity; Godiard, Laurence

    2016-01-01

    Plasmopara halstedii is an obligate biotrophic oomycete causing downy mildew disease on sunflower, Helianthus annuus, an economically important oil crop. Severe symptoms of the disease (e.g., plant dwarfism, leaf bleaching, sporulation and production of infertile flower) strongly impair seed yield. Pl resistance genes conferring resistance to specific P. halstedii pathotypes were located on sunflower genetic map but yet not cloned. They are present in cultivated lines to protect them against downy mildew disease. Among the 16 different P. halstedii pathotypes recorded in France, pathotype 710 is frequently found, and therefore continuously controlled in sunflower by different Pl genes. High-throughput sequencing of cDNA from P. halstedii led us to identify potential effectors with the characteristic RXLR or CRN motifs described in other oomycetes. Expression of six P. halstedii putative effectors, five RXLR and one CRN, was analyzed by qRT-PCR in pathogen spores and in the pathogen infecting sunflower leaves and selected for functional analyses. We developed a new method for transient expression in sunflower plant leaves and showed for the first time subcellular localization of P. halstedii effectors fused to a fluorescent protein in sunflower leaf cells. Overexpression of the CRN and of 3 RXLR effectors induced hypersensitive-like cell death reactions in some sunflower near-isogenic lines resistant to pathotype 710 and not in susceptible corresponding lines, suggesting they could be involved in Pl loci-mediated resistances. PMID:28066456

  9. Specific in planta recognition of two GKLR proteins of the downy mildew Bremia lactucae revealed in a large effector screen in lettuce.

    Science.gov (United States)

    Stassen, Joost H M; den Boer, Erik; Vergeer, Pim W J; Andel, Annemiek; Ellendorff, Ursula; Pelgrom, Koen; Pel, Mathieu; Schut, Johan; Zonneveld, Olaf; Jeuken, Marieke J W; Van den Ackerveken, Guido

    2013-11-01

    Breeding lettuce (Lactuca sativa) for resistance to the downy mildew pathogen Bremia lactucae is mainly achieved by introgression of dominant downy mildew resistance (Dm) genes. New Bremia races quickly render Dm genes ineffective, possibly by mutation of recognized host-translocated effectors or by suppression of effector-triggered immunity. We have previously identified 34 potential RXLR(-like) effector proteins of B. lactucae that were here tested for specific recognition within a collection of 129 B. lactucae-resistant Lactuca lines. Two effectors triggered a hypersensitive response: BLG01 in 52 lines, predominantly L. saligna, and BLG03 in two L. sativa lines containing Dm2 resistance. The N-terminal sequences of BLG01 and BLG03, containing the signal peptide and GKLR variant of the RXLR translocation motif, are not required for in planta recognition but function in effector delivery. The locus responsible for BLG01 recognition maps to the bottom of lettuce chromosome 9, whereas recognition of BLG03 maps in the RGC2 cluster on chromosome 2. Lactuca lines that recognize the BLG effectors are not resistant to Bremia isolate Bl:24 that expresses both BLG genes, suggesting that Bl:24 can suppress the triggered immune responses. In contrast, lettuce segregants displaying Dm2-mediated resistance to Bremia isolate Bl:5 are responsive to BLG03, suggesting that BLG03 is a candidate Avr2 protein.

  10. Coping with uncertainty: woodpecker finches (Cactospiza pallida from an unpredictable habitat are more flexible than birds from a stable habitat.

    Directory of Open Access Journals (Sweden)

    Sabine Tebbich

    Full Text Available Behavioural flexibility is thought to be a major factor in evolution. It may facilitate the discovery and exploitation of new resources, which in turn may expose populations to novel selective forces and facilitate adaptive radiation. Darwin's finches are a textbook example of adaptive radiation. They are fast learners and show a range of unusual foraging techniques, probably as a result of their flexibility. In this study we aimed to test whether variability of the environment is correlated with flexibility. We compared woodpecker finches from a dry area (hereafter, Arid Zone, where food availability is variable, with individuals from a cloud forest (hereafter, Scalesia zone where food abundance is stable. As parameters for flexibility, we measured neophilia and neophobia, which are two aspects of reaction to novelty, reversal learning and problem-solving. We found no differences in performance on a problem-solving task but, in line with our prediction, individuals from the Arid Zone were significantly faster reversal learners and more neophilic than their conspecifics from the Scalesia zone. The latter result supports the notion that environmental variability drives flexibility. In contrast to our prediction, Arid Zone birds were even more neophobic than birds from the Scalesia Zone. The latter result could be the consequence of differences in predation pressure between the two vegetation zones.

  11. Extrapair paternity and maternity in the three-toed woodpecker, Picoides tridactylus: insights from microsatellite-based parentage analysis.

    Directory of Open Access Journals (Sweden)

    Meng-Hua Li

    2009-11-01

    Full Text Available Molecular techniques have revealed that avian mating systems are more diverse and complex than previously thought. We used microsatellite markers to determine genetic parentage, the prevalence of extrapair paternity and quasi-parasitism (i.e. situations where a male's extrapair mate lay in his nest in a socially monogamous population of three-toed woodpeckers (Picoides tridactylus in southern Finland. A total of 129 adults and nestlings, representing 5-9 families annually from 2004-2007, were genotyped at up to ten microsatellite loci. The results of genetic assignment tests confirmed that monogamous parentage characterized the majority (84.6%, 22/26 of broods, and that most (93.8%, 75/80 nestlings were the offspring of their social parents. Two of 80 nestlings (2.5% in two of 26 broods (7.7% were sired by extrapair males and quasi-parasitism occurred in 3.8% (3/80 of nestlings and 7.7% (2/26 of broods. Hence, the levels of extrapair parentage were low, possibly because both genetic polygyny and polyandry are constrained by the high paternal effort required for parental care. The co-occurrence of low levels of extrapair paternity and quasi-parasitism are discussed in light of ecological and behavioural factors characterizing the species biology.

  12. Extrapair paternity and maternity in the three-toed woodpecker, Picoides tridactylus: insights from microsatellite-based parentage analysis.

    Science.gov (United States)

    Li, Meng-Hua; Välimäki, Kaisa; Piha, Markus; Pakkala, Timo; Merilä, Juha

    2009-11-18

    Molecular techniques have revealed that avian mating systems are more diverse and complex than previously thought. We used microsatellite markers to determine genetic parentage, the prevalence of extrapair paternity and quasi-parasitism (i.e. situations where a male's extrapair mate lay in his nest) in a socially monogamous population of three-toed woodpeckers (Picoides tridactylus) in southern Finland. A total of 129 adults and nestlings, representing 5-9 families annually from 2004-2007, were genotyped at up to ten microsatellite loci. The results of genetic assignment tests confirmed that monogamous parentage characterized the majority (84.6%, 22/26) of broods, and that most (93.8%, 75/80) nestlings were the offspring of their social parents. Two of 80 nestlings (2.5%) in two of 26 broods (7.7%) were sired by extrapair males and quasi-parasitism occurred in 3.8% (3/80) of nestlings and 7.7% (2/26) of broods. Hence, the levels of extrapair parentage were low, possibly because both genetic polygyny and polyandry are constrained by the high paternal effort required for parental care. The co-occurrence of low levels of extrapair paternity and quasi-parasitism are discussed in light of ecological and behavioural factors characterizing the species biology.

  13. Detection of Verticillium wilt of olive trees and downy mildew of opium poppy using hyperspectral and thermal UAV imagery

    Science.gov (United States)

    Calderón Madrid, Rocío; Navas Cortés, Juan Antonio; Montes Borrego, Miguel; Landa del Castillo, Blanca Beatriz; Lucena León, Carlos; Jesús Zarco Tejada, Pablo

    2014-05-01

    The present study explored the use of high-resolution thermal, multispectral and hyperspectral imagery as indicators of the infections caused by Verticillium wilt (VW) in olive trees and downy mildew (DM) in opium poppy fields. VW, caused by the soil-borne fungus Verticillium dahliae, and DM, caused by the biotrophic obligate oomycete Peronospora arborescens, are the most economically limiting diseases of olive trees and opium poppy, respectively, worldwide. V. dahliae infects the plant by the roots and colonizes its vascular system, blocking water flow and eventually inducing water stress. P. arborescens colonizes the mesophyll, appearing the first symptoms as small chlorotic leaf lesions, which can evolve to curled and thickened tissues and systemic infections that become deformed and necrotic as the disease develops. The work conducted to detect VW and DM infection consisted on the acquisition of time series of airborne thermal, multispectral and hyperspectral imagery using 2-m and 5-m wingspan electric Unmanned Aerial Vehicles (UAVs) in spring and summer of three consecutive years (2009 to 2011) for VW detection and on three dates in spring of 2009 for DM detection. Two 7-ha commercial olive orchards naturally infected with V. dahliae and two opium poppy field plots artificially infected by P. arborescens were flown. Concurrently to the airborne campaigns, olive orchards and opium poppy fields were assessed "in situ" to assess actual VW severity and DM incidence. Furthermore, field measurements were conducted at leaf and crown level. The field results related to VW detection showed a significant increase in crown temperature (Tc) minus air temperature (Ta) and a decrease in leaf stomatal conductance (G) as VW severity increased. This reduction in G was associated with a significant increase in the Photochemical Reflectance Index (PRI570) and a decrease in chlorophyll fluorescence. DM asymptomatic leaves showed significantly higher NDVI and lower green/red index

  14. Coupling Spore Traps and Quantitative PCR Assays for Detection of the Downy Mildew Pathogens of Spinach (Peronospora effusa) and Beet (P. schachtii)

    Science.gov (United States)

    Klosterman, Steven J.; Anchieta, Amy; McRoberts, Neil; Koike, Steven T.; Subbarao, Krishna V.; Voglmayr, Hermann; Choi, Young-Joon; Thines, Marco; Martin, Frank N.

    2016-01-01

    Downy mildew of spinach (Spinacia oleracea), caused by Peronospora effusa, is a production constraint on production worldwide, including in California, where the majority of U.S. spinach is grown. The aim of this study was to develop a real-time quantitative polymerase chain reaction (qPCR) assay for detection of airborne inoculum of P. effusa in California. Among oomycete ribosomal DNA (rDNA) sequences examined for assay development, the highest nucleotide sequence identity was observed between rDNA sequences of P. effusa and P. schachtii, the cause of downy mildew on sugar beet and Swiss chard in the leaf beet group (Beta vulgaris subsp. vulgaris). Single-nucleotide polymorphisms were detected between P. effusa and P. schachtii in the 18S rDNA regions for design of P. effusa- and P. schachtii-specific TaqMan probes and reverse primers. An allele-specific probe and primer amplification method was applied to determine the frequency of both P. effusa and P. schachtii rDNA target sequences in pooled DNA samples, enabling quantification of rDNA of P. effusa from impaction spore trap samples collected from spinach production fields. The rDNA copy numbers of P. effusa were, on average, ≈3,300-fold higher from trap samples collected near an infected field compared with those levels recorded at a site without a nearby spinach field. In combination with disease-conducive weather forecasting, application of the assays may be helpful to time fungicide applications for disease management. PMID:24964150

  15. Disentangling Peronospora on Papaver: Phylogenetics, Taxonomy, Nomenclature and Host Range of Downy Mildew of Opium Poppy (Papaver somniferum) and Related Species

    Science.gov (United States)

    Voglmayr, Hermann; Montes-Borrego, Miguel; Landa, Blanca B.

    2014-01-01

    Based on sequence data from ITS rDNA, cox1 and cox2, six Peronospora species are recognised as phylogenetically distinct on various Papaver species. The host ranges of the four already described species P. arborescens, P. argemones, P. cristata and P. meconopsidis are clarified. Based on sequence data and morphology, two new species, P. apula and P. somniferi, are described from Papaver apulum and P. somniferum, respectively. The second Peronospora species parasitizing Papaver somniferum, that was only recently recorded as Peronospora cristata from Tasmania, is shown to represent a distinct taxon, P. meconopsidis, originally described from Meconopsis cambrica. It is shown that P. meconopsidis on Papaver somniferum is also present and widespread in Europe and Asia, but has been overlooked due to confusion with P. somniferi and due to less prominent, localized disease symptoms. Oospores are reported for the first time for P. meconopsidis from Asian collections on Papaver somniferum. Morphological descriptions, illustrations and a key are provided for all described Peronospora species on Papaver. cox1 and cox2 sequence data are confirmed as equally good barcoding loci for reliable Peronospora species identification, whereas ITS rDNA does sometimes not resolve species boundaries. Molecular phylogenetic data reveal high host specificity of Peronospora on Papaver, which has the important phytopathological implication that wild Papaver spp. cannot play any role as primary inoculum source for downy mildew epidemics in cultivated opium poppy crops. PMID:24806292

  16. Relationship of coarse woody debris to arthropod Availability for Red-Cockaded Woodpeckers and other bark-foraging birds on loblolly pine boles.

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Scott; Hanula, James, L.

    2008-04-01

    Abstract This study determined if short-term removal of coarse woody debris would reduce prey available to red-cockaded woodpeckers (Picoides borealis Vieillot) and other bark-foraging birds at the Savannah River Site in Aiken and Barnwell counties, SC. All coarse woody debris was removed from four 9-ha plots of mature loblolly pine (Pinus taeda L.) in 1997 and again in 1998. We sampled arthropods in coarse woody debris removal and control stands using crawl traps that captured arthropods crawling up tree boles, burlap bands wrapped around trees, and cardboard panels placed on the ground. We captured 27 orders and 172 families of arthropods in crawl traps whereas 20 arthropod orders were observed under burlap bands and cardboard panels. The most abundant insects collected from crawl traps were aphids (Homoptera: Aphididae) and ants (Hymenoptera: Forrnicidae). The greatest biomass was in the wood cockroaches (Blattaria: Blattellidae), caterpillars (Lepidoptera) in the Family Noctuidae, and adult weevils (Coleoptera: Curculionidae). The most common group observed underneath cardboard panels was lsoptera (termites), and the most common taxon under burlap bands was wood cockroaches. Overall, arthropod abundance and biomass captured in crawl traps was similar in control and removal plots. In contrast, we observed more arthropods under burlap bands (mean & SE; 3,021.5 k 348.6, P= 0.03) and cardboard panels (3,537.25 k 432.4, P= 0.04) in plots with coarse woody debris compared with burlap bands (2325 + 171.3) and cardboard panels (2439.75 + 288.9) in plots where coarse woody debris was removed. Regression analyses showed that abundance beneath cardboard panels was positively correlated with abundance beneath burlap bands demonstrating the link between abundance on the ground with that on trees. Our results demonstrate that short-term removal of coarse woody debris from pine forests reduced overall arthropod availability to bark-foraging birds.

  17. Ensemble modeling to predict habitat suitability for a large-scale disturbance specialist.

    Science.gov (United States)

    Latif, Quresh S; Saab, Victoria A; Dudley, Jonathan G; Hollenbeck, Jeff P

    2013-11-01

    To conserve habitat for disturbance specialist species, ecologists must identify where individuals will likely settle in newly disturbed areas. Habitat suitability models can predict which sites at new disturbances will most likely attract specialists. Without validation data from newly disturbed areas, however, the best approach for maximizing predictive accuracy can be unclear (Northwestern U.S.A.). We predicted habitat suitability for nesting Black-backed Woodpeckers (Picoides arcticus; a burned-forest specialist) at 20 recently (≤6 years postwildfire) burned locations in Montana using models calibrated with data from three locations in Washington, Oregon, and Idaho. We developed 8 models using three techniques (weighted logistic regression, Maxent, and Mahalanobis D (2) models) and various combinations of four environmental variables describing burn severity, the north-south orientation of topographic slope, and prefire canopy cover. After translating model predictions into binary classifications (0 = low suitability to unsuitable, 1 = high to moderate suitability), we compiled "ensemble predictions," consisting of the number of models (0-8) predicting any given site as highly suitable. The suitability status for 40% of the area burned by eastside Montana wildfires was consistent across models and therefore robust to uncertainty in the relative accuracy of particular models and in alternative ecological hypotheses they described. Ensemble predictions exhibited two desirable properties: (1) a positive relationship with apparent rates of nest occurrence at calibration locations and (2) declining model agreement outside surveyed environments consistent with our reduced confidence in novel (i.e., "no-analogue") environments. Areas of disagreement among models suggested where future surveys could help validate and refine models for an improved understanding of Black-backed Woodpecker nesting habitat relationships. Ensemble predictions presented here can help guide

  18. Development and dissection of diagnostic SNP markers for the downy mildew resistance genes Pl Arg and Pl 8 and maker-assisted gene pyramiding in sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Qi, L L; Talukder, Z I; Hulke, B S; Foley, M E

    2017-06-01

    Diagnostic DNA markers are an invaluable resource in breeding programs for successful introgression and pyramiding of disease resistance genes. Resistance to downy mildew (DM) disease in sunflower is mediated by Pl genes which are known to be effective against the causal fungus, Plasmopara halstedii. Two DM resistance genes, Pl Arg and Pl 8 , are highly effective against P. halstedii races in the USA, and have been previously mapped to the sunflower linkage groups (LGs) 1 and 13, respectively, using simple sequence repeat (SSR) markers. In this study, we developed high-density single nucleotide polymorphism (SNP) maps encompassing the Pl arg and Pl 8 genes and identified diagnostic SNP markers closely linked to these genes. The specificity of the diagnostic markers was validated in a highly diverse panel of 548 sunflower lines. Dissection of a large marker cluster co-segregated with Pl Arg revealed that the closest SNP markers NSA_007595 and NSA_001835 delimited Pl Arg to an interval of 2.83 Mb on the LG1 physical map. The SNP markers SFW01497 and SFW06597 delimited Pl 8 to an interval of 2.85 Mb on the LG13 physical map. We also developed sunflower lines with homozygous, three gene pyramids carrying Pl Arg , Pl 8 , and the sunflower rust resistance gene R 12 using the linked SNP markers from a segregating F 2 population of RHA 340 (carrying Pl 8 )/RHA 464 (carrying Pl Arg and R 12 ). The high-throughput diagnostic SNP markers developed in this study will facilitate marker-assisted selection breeding, and the pyramided sunflower lines will provide durable resistance to downy mildew and rust diseases.

  19. A nested-polymerase chain reaction protocol for detection and population biology studies of Peronospora arborescens, the downy mildew pathogen of opium poppy, using herbarium specimens and asymptomatic, fresh plant tissues.

    Science.gov (United States)

    Montes-Borrego, Miguel; Muñoz Ledesma, Francisco J; Jiménez-Díaz, Rafael M; Landa, Blanca B

    2009-01-01

    A sensitive nested-polymerase chain reaction (PCR) protocol was developed using either of two primer pairs that improves the in planta detection of Peronospora arborescens DNA. The new protocol represented an increase in sensitivity of 100- to 1,000-fold of detection of the oomycete in opium poppy tissue compared with the detection limit of single PCR using the same primer pairs. The new protocol allowed amplification of 5 to 0.5 fg of Peronospora arborescens DNA mixed with Papaver somniferum DNA. The protocol proved useful for amplifying Peronospora arborescens DNA from 96-year-old herbarium specimens of Papaver spp. and to demonstrate that asymptomatic, systemic infections by Peronospora arborescens can occur in wild Papaver spp. as well as in cultivated opium poppy. Also, the increase in sensitivity of the protocol made possible the detection of seedborne Peronospora arborescens in commercial opium poppy seed stocks in Spain with a high frequency, which poses a threat for pathogen spread. Direct sequencing of purified amplicons allowed alignment of a Peronospora arborescens internal transcribed spacer (ITS) ribosomal DNA (rDNA) sequence up to 730-bp long when combining the sequences obtained with the two primer sets. Maximum parsimony analysis of amplified Peronospora arborescens ITS rDNA sequences from specimens of Papaver dubium, P. hybridum, P. rhoeas, and P. somniferum from different countries indicated for the first time that a degree of host specificity may exist within populations of Peronospora arborescens. The reported protocol will be useful for epidemiological and biogeographical studies of downy mildew diseases as well as to unravel misclassification of Peronospora arborescens and Peronospora cristata, the reported causal agents of the opium poppy downy mildew disease.

  20. Reaction of melon genotypes to the gummy stem blight and the downy mildew Reação de genótipos de melão ao crestamento gomoso e ao míldio

    Directory of Open Access Journals (Sweden)

    Gil R dos Santos

    2009-06-01

    Full Text Available The gummy stem blight (Didymella bryoniae and the downy mildew (Pseudoperonospora cubensis are two foremost melon (Cucumis melo diseases, considering their effects on yield and fruit quality. Despite the importance of such diseases, relatively few studies have been done so far on the identification of resistance sources to D. bryoniae and P. cubensis in Brazil. This work aimed at evaluating the resistance of commercial melon genotypes to the gummy stem blight and the downy mildew. Firstly, the most aggressive and representative D. bryoniae isolate was selected. Subsequently, the resistance of 86 melon genotypes to stem infection was studied upon greenhouse conditions by inoculating with the previously selected isolate. Afterwards, the resistance to mildew and leaf infection by D. bryoniae of 28 melon genotypes was evaluated in the field, under natural infection. In the greenhouse, all 86 melon genotypes were infected and showed stem infection symptoms caused by D. bryoniae four days after inoculation. Nevertheless, a significant variation on the resistance levels of the melon genotypes was found. Under field conditions and natural inoculation, genotypes Taslaki and Sary Juliabi were the most susceptible to leaf infection by D. bryoniae, significantly differing from the other genotypes. The lowest levels of susceptibility were identified in genotypes Perlita Busle S1, Valenciano Elíptico, Glaver, MR1, and 2526. All genotypes were susceptible to the downy mildew, albeit differing in susceptibility levels.O crestamento gomoso do caule (Didymella bryoniae e o míldio (Pseudoperonospora cubensis estão entre as principais doenças do meloeiro (Cucumis melo ocasionando redução da produtividade e da qualidade dos frutos. Apesar da importância dessas doenças, são poucos os trabalhos envolvendo a identificação de fontes de resistência a D. bryoniae e a P. cubensis no Brasil. O objetivo deste trabalho foi avaliar a resistência de gen

  1. Use of cccupancy models to evaluate expert knowledge-based species-habitat relationships

    Science.gov (United States)

    Iglecia, Monica N.; Collazo, Jaime A.; McKerrow, Alexa

    2012-01-01

    Expert knowledge-based species-habitat relationships are used extensively to guide conservation planning, particularly when data are scarce. Purported relationships describe the initial state of knowledge, but are rarely tested. We assessed support in the data for suitability rankings of vegetation types based on expert knowledge for three terrestrial avian species in the South Atlantic Coastal Plain of the United States. Experts used published studies, natural history, survey data, and field experience to rank vegetation types as optimal, suitable, and marginal. We used single-season occupancy models, coupled with land cover and Breeding Bird Survey data, to examine the hypothesis that patterns of occupancy conformed to species-habitat suitability rankings purported by experts. Purported habitat suitability was validated for two of three species. As predicted for the Eastern Wood-Pewee (Contopus virens) and Brown-headed Nuthatch (Sitta pusilla), occupancy was strongly influenced by vegetation types classified as “optimal habitat” by the species suitability rankings for nuthatches and wood-pewees. Contrary to predictions, Red-headed Woodpecker (Melanerpes erythrocephalus) models that included vegetation types as covariates received similar support by the data as models without vegetation types. For all three species, occupancy was also related to sampling latitude. Our results suggest that covariates representing other habitat requirements might be necessary to model occurrence of generalist species like the woodpecker. The modeling approach described herein provides a means to test expert knowledge-based species-habitat relationships, and hence, help guide conservation planning.

  2. Use of Occupancy Models to Evaluate Expert Knowledge-based Species-Habitat Relationships

    Directory of Open Access Journals (Sweden)

    Monica N. Iglecia

    2012-12-01

    Full Text Available Expert knowledge-based species-habitat relationships are used extensively to guide conservation planning, particularly when data are scarce. Purported relationships describe the initial state of knowledge, but are rarely tested. We assessed support in the data for suitability rankings of vegetation types based on expert knowledge for three terrestrial avian species in the South Atlantic Coastal Plain of the United States. Experts used published studies, natural history, survey data, and field experience to rank vegetation types as optimal, suitable, and marginal. We used single-season occupancy models, coupled with land cover and Breeding Bird Survey data, to examine the hypothesis that patterns of occupancy conformed to species-habitat suitability rankings purported by experts. Purported habitat suitability was validated for two of three species. As predicted for the Eastern Wood-Pewee (Contopus virens and Brown-headed Nuthatch (Sitta pusilla, occupancy was strongly influenced by vegetation types classified as "optimal habitat" by the species suitability rankings for nuthatches and wood-pewees. Contrary to predictions, Red-headed Woodpecker (Melanerpes erythrocephalus models that included vegetation types as covariates received similar support by the data as models without vegetation types. For all three species, occupancy was also related to sampling latitude. Our results suggest that covariates representing other habitat requirements might be necessary to model occurrence of generalist species like the woodpecker. The modeling approach described herein provides a means to test expert knowledge-based species-habitat relationships, and hence, help guide conservation planning.

  3. Application and validation of a warning system for grapevine downy mildew controlusing fungicides Aplicação e validação de um sistema de aviso para o controle do míldio da videira, com fungicidas

    Directory of Open Access Journals (Sweden)

    Erlei Melo Reis

    2013-03-01

    Full Text Available Most warning systems for plant disease control are based on Vinho, in Bento Gonçalves - RS, during the growing seasons 2000/ weather models dependent on the relationships between leaf wetness 01, 2002/03 and 2003/2004, using the grape cultivar Isabel. The duration and mean air temperature in this period considering the conventional system used by local growers was compared with the target disease intensity. For the development of a warning system to new warning system by using different cumulative daily disease severity control grapevine downy mildew, the equation generated by Lalancette values (CDDSV as the criterion to schedule fungicide application and et al. (7 was used. This equation was employed to elaborate a critical reapplication. In experiments conducted in 2003/04, CDDSV of 12 - period table and program a computerized device, which records, though 14 showed promising to schedule the first spraying and the interval electronic sensors, leaf wetness duration, mean temperature in this between fungicide applications, reducing by 37.5% the number of period and automatically calculates the daily value of probability of applications and maintaining the same control efficiency in leaves infection occurrence. The system was validated at Embrapa Uva e and bunches, similarly to the conventional system.A maioria dos sistemas de aviso para o controle de doenças de O sistema foi validado na Embrapa Uva e Vinho, em Bento Gonçalves plantas utilizam como fundamento o modelo climático baseado - RS, conduzido nas safras agrícolas de 2000/01, 2002/03 e 2003/ nas interações entre a duração do molhamento foliar e a 2004 utilizando-se o cultivar Isabel. O sistema convencional utilizado temperatura média nesse período sobre a intensidade da doença pelos produtores foi comparado com o modelo de aviso utilizando alvo. No desenvolvimento de um modelo de aviso para o controle como critério indicador do momento para a aplicação e reaplicação do m

  4. Dead Trees Bring Life to Forest Critters

    Science.gov (United States)

    Thomas Nicholls; Mike Ostry

    2003-01-01

    What good is a dying or dead tree in a forest? Dead and dying trees don't awe us with their beauty; they just stand or lie there on the forest floor, offering no promise of lumber or other wood products we need. But if we look more closely at such trees, we may see lots of life in them: a raccoon family huddled in a burrow, a downy woodpecker excavating another...

  5. Six Downie Nocturnes - for viola and piano

    OpenAIRE

    Lancaster, David

    2013-01-01

    This music comprises three pairs of highly contrasted miniatures; I have separated each movement from its ‘companion’ in order to explore possible relationships between the different pairs (in spite of the stark contrasts between them) and to fracture the natural continuity of the music.\\ud \\ud The outer pieces are a sustained chorale, plaintive and largely undecorated. The second and fourth Nocturnes are a small tribute to Elliott Carter who had died while I was at work on this commission. W...

  6. Influência das condições climáticas sobre a eficácia de fungicidas empregados para o controle do míldio em Vitis vinifera Effect of environmental conditions on efficacy of fungicides to downy mildew control in Vitis vinifera

    Directory of Open Access Journals (Sweden)

    Ana Beatriz Costa Czermainski

    2004-02-01

    Full Text Available Um dos fatores a serem manejados para a máxima produtividade de um vinhedo é o míldio, doença causada por Plasmopara viticola, que afeta regiões produtoras de uva do mundo inteiro. No Brasil, são necessárias diversas aplicações de fungicida para seu controle. Diferentes princípios ativos são encontrados no mercado. Com base em resultados de ensaios de fungicidas para controle do míldio em Vitis vinifera conduzidos em 1995 e 1996, foi analisada a influência dos fatores climáticos temperatura do ar, precipitação e umidade relativa do ar sobre a eficácia dos produtos disponíveis. Os experimentos foram instalados na Embrapa Uva e Vinho, sobre a cv. Tannat, conduzida no sistema espaldeira. A análise dos fatores ambientais apontou períodos de infecções primárias e secundárias. A maior ocorrência de chuvas e alta umidade relativa do ar foram determinantes da maior severidade do míldio no ano de 1996. A análise da incidência e do índice de intensidade de doença em folhas e em cachos, indicou maior eficácia dos fungicidas cymoxanil + mancozeb, metalaxil + mancozeb e dithianona, nos dois anos. Os princípios ativos cúpricos - oxicloreto de cobre, isolado ou combinado com mancozeb, e sulfato de cobre - não foram eficazes para controlar o míldio nos cachos sob condições climáticas favoráveis à doença.One of the factors to be managed for maximum vineyard productivity is the downy mildew, disease caused by Plasmopara viticola that affects grape production in many parts of the world. In Brazil, several fungicide applications for its control are necessary. Different active ingredients are available on the market. The influence of climatic factors (air temperature, rainfall and relative humidity on fungicide efficacy in Vitis vinifera was analyzed using results of fungicide trials for downy mildew control as a base. The experiments were carried out at Embrapa Uva e Vinho with the cv. Tannat conducted on vertical trellis

  7. Modeling the Effects of Land Use on the Quality of Water, Air, Noise, and Habitat for a Five-County Region in Georgia

    Directory of Open Access Journals (Sweden)

    Virginia H. Dale

    2008-06-01

    Full Text Available A computer simulation model, the Regional Simulator (RSim, was constructed to project how land-use changes affect the quality of water, air, noise, and habitat of species of special concern. RSim was designed to simulate these environmental impacts for five counties in Georgia that surround and include Fort Benning. The model combines existing data and modeling approaches to simulate the effects of land-cover changes on: nutrient export by hydrological unit; peak 8-h average ozone concentrations; noise caused by small arms and blasts; and habitat changes for the rare Red-cockaded Woodpecker (Picoides borealis and gopher tortoise (Gopherus polyphemus. The model also includes submodules for urban growth, new urbanization influenced by existing roads, nonurban land cover transitions, and a new military training area under development at Fort Benning. The model was run under scenarios of business as usual (BAU and greatly increased urban growth for the region. The projections show that the effects of high urban growth will likely differ from those of BAU for noise and nitrogen and phosphorus loadings to surface water, but not for peak airborne ozone concentrations, at least in the absence of associated increases in industry and transportation use or technology changes. In both scenarios, no effects of urban growth are anticipated for existing populations of the federally endangered Red-cockaded Woodpecker. In contrast, habitat for gopher tortoise in the five-county region is projected to decline by 5 and 40% in the BAU and high urban growth scenarios, respectively. RSim is designed to assess the relative environmental impacts of planned activities both inside and outside military installations and to address concerns related to encroachment and transboundary influences.

  8. Novas raças de Bremia lactucae, agente causador do míldio da alface, identificadas no estado de São Paulo New races of Bremia lactucae, causal agent of lettuce downy mildew, identified in São Paulo state, Brazil

    Directory of Open Access Journals (Sweden)

    Jean de O Souza

    2011-09-01

    Full Text Available O objetivo deste trabalho foi relatar o surgimento de raças de Bremia lactucae, agente causal do míldio nas principais regiões produtoras de alface do estado de São Paulo. O estudo foi realizado no Laboratório de Melhoramento Genético de Hortaliças do Departamento de Produção Vegetal da UNESP, Campus de Jaboticabal. No período de 2006 e 2007, foram coletados 36 isolados de B. lactucae de diferentes regiões produtoras de alface no estado. Para identificação das raças foram utilizadas as cultivares diferenciadoras conforme o código "Sextet". Foram identificadas três novas raças, SPBl:02, SPBl:03 e SPBl:04 com os referidos comportamentos do fungo: (63/31/19/00, (63/63/19/00 e (63/63/03/00. Os genes Dm-14, Dm-17, Dm-18, Dm-37 e Dm-38 conferem resistência a essas novas raças identificadas.The objective of this paper was to report new races of lettuce downy mildew causal agent Bremia lactucae in São Paulo State. The study was carried out in the laboratory of Crop Genetics in the Department of Crop Science at the college of Agricultural and Veterinary Sciences, Jaboticabal campus. A total of 36 isolates of B. lactucae was collected in different regions. The identification of races was based on compatibility reaction on the differential cultivars of the "Sextet". Three new races of B. lactucae, SPBl:02 (63/31/19/00, SPBl:03 (63/63/19/00 and SPBl:04 (63/63/03/00 were identified according to "Sextet" code. Genes Dm-14, Dm-17, Dm-18, Dm-37 and Dm-38 confer resistance to these new races identified.

  9. Aplicação foliar de tratamentos para o controle do míldio e da podridão-de-escamas de bulbos de cebola Foliar spray of treatments in the control of downy mildew and bulb rot in onion

    Directory of Open Access Journals (Sweden)

    João Américo Wordell Filho

    2007-12-01

    Full Text Available Em experimento de campo, avaliou-se o efeito da aplicação foliar de tratamentos para o controle do míldio (Peronospora destructor e da podridão de bulbos (Burkholderia cepacia de cebola: testemunha, clorotalonil/metalaxyl + clorotalonil, fosfito de potássio, fertilizante foliar (03-00-16, N-P-K, calda bordalesa, calda bordalesa/fosfito de potássio, acibenzolar-S-methyl, pulverizados semanalmente; extrato de alga (Ulva fasciata e ulvana, aplicados a cada 7, 14 e 21 dias. Somente a pulverização semanal com fungicidas sintéticos ou com o fertilizante (03-00-16; 400 mL de p.c./100 L foi capaz de reduzir significativamente a severidade do míldio, em 60 ou 23%, respectivamente, em relação à testemunha não pulverizada, sem aumentar o rendimento de bulbos. O tratamento com fertilizantes ricos em potássio resultou em maior incidência da podridão de bulbos armazenados por cinco meses. O conteúdo de açúcares solúveis e incidência da podridão de bulbos de cebola foram correlacionados significativamente (-0,629, p A field experiment was carried out to evaluate the effect of foliar sprays with the following treatments on the downy mildew (Peronospora destructor and bulb rot (Burkholderia cepacia in onions: non-treated control, fungicide chlorotalonil/metalaxyl + chlorotalonil, potassium phosphite, foliar fertilizer (03-00-16, N-P-K, bordeaux mixture, bordeaux mixture/potassium phosphite, acibenzolar-S-methyl weekly applied; extract of alga Ulva fasciata and ulvan sprayed every 7, 14 and 21 days. Only the weekly spraying of fungicides and fertilizer (03-00-16, 400 mL/100 L significantly reduced the mildew severity by 60 and 23%, respectively, but did not increase the bulb yield. The foliar application of potassium rich fertilizers resulted in a higher incidence of rotten bulbs after 5 months in storage. Soluble sugar content and rot incidence of onion bulbs were significantly correlated (-0,629, p < 0,05.

  10. Detecção e variabilidade de Plasmopara halstedii no Brasil e avaliação da resistência de genótipos de girassol ao míldio Detection and variability of Plasmopara halstedii in Brazil and resistance of sunflower genotypes to downy mildew

    Directory of Open Access Journals (Sweden)

    Regina Maria Villas Bôas de Campos Leite

    2007-12-01

    Full Text Available Este trabalho foi conduzido com o objetivo de identificar a raça fisiológica de Plasmopara halstedii que ocorreu em plantas de girassol coletadas no campo experimental da Embrapa Soja, Londrina, PR, em 1998, 2001 e 2002 e avaliar a reação de genótipos de girassol ao míldio. Plântulas de girassol das diferenciadoras de raças e das cultivares foram inoculadas com suspensão de zoosporângios do patógeno e foram plantadas em caixas contendo areia autoclavada. As plântulas foram mantidas em câmara climatizada, com temperatura controlada em 21ºC, por 11 dias. Em seguida, as plantas foram aspergidas intensamente com água destilada, cobertas com saco plástico e mantidas no escuro, a 18ºC. No dia seguinte, foi observada a presença de esporulação nos cotilédones. As plantas que apresentaram esporulação foram consideradas suscetíveis e as sem esporulação foram resistentes. O resultado indicou tratar-se da raça 330 (antiga raça 7 americana, nas três ocasiões. Os genótipos de girassol Embrapa 122, BRS 191 e as cultivares de girassol ornamental BRS Capri M, BRS Encanto M, BRS Oásis, BRS Paixão M, BRS Pesqueiro M, BRS Refúgio M, BRS Saudade M e BRS Saudade U e seus respectivos parentais foram suscetíveis a P. halstedii raça 330. Os genótipos AGROBEL 910, AGROBEL 920, AGROBEL 960, AGROBEL 965, C11, EXP38, M734, M742 e RUMBOSOL 91 foram resistentes à raça 330 do patógeno e podem ser indicados aos agricultores para uso em regiões de risco de ocorrência da doença.This research was carried out for identifying the physiological race of Plasmopara halstedii occurring in sunflower at the experimental field of Embrapa Soybean, Londrina, PR, Brazil, in 1998, 2001 and 2002 by evaluating the reaction of sunflower genotypes inoculated with downy mildew pathogen. Sunflower seedlings of the differentials set to identify races and of the cultivars were inoculated by immersion in zoosporangia suspension and were grown in autoclaved

  11. Effects of leaf area of downy oak (Quercus pubescens Willd ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-18

    Aug 18, 2009 ... On the other hand, the light energy that is held by a leaf depends on the size of the leaf area (leaf surface). The measure of the leaf surface area (l.a.) is total leaf surface area of the plant (m2). The ratio between the total surface leaf area of a plant and the land area it covers (m2/ha or m2/m2) at a certain ...

  12. Atahualpa's revenge: the spread of quinoa downy mildew

    OpenAIRE

    Testen, Anna L.; Backman, Paul A.

    2011-01-01

    Metadata only record The Andean crop quinoa, Chenopodium quinoa, has gained popularity in recent years due to its nutritious seed and desirable agricultural traits, such as its tolerance to drought and high saline soils. Prized by the Inca, quinoa is now highly desirable to health conscious consumers in North America and Europe. Quinoa also has interesting applications to plant pathology, including being a “universal” virus host as well as its production of antimicrobial compounds. Quinoa ...

  13. Prediction of biological sensors appearance with ARIMA models as a tool for Integrated Pest Management protocols.

    Science.gov (United States)

    Fernández-González, María; Ramos-Valcárcel, David; Aira, María Jesús; Rodríguez-Rajo, Francisco Javier

    2016-01-01

    Powdery mildew caused by Uncinula necator and Downy mildew produced by Plasmopara viticola are the most common diseases in the North-West Spain vineyards. Knowledge of airborne spore concentrations could be a useful tool in the Integrated Pest Management protocols in order to reduce the number of pesticide treatments, applied only when there is a real risk of infection. The study was carried out in a vineyard of the D. O. Ribeiro, in the North-West Spain, during the grapevine active period 2004-2012. A Hirts-type volumetric spore-trap was used for the aerobiological monitoring. During the study period the annual total U. necator spores amount ranged from the 578 spores registered in 2007 to the 4,145 spores sampled during 2008. The highest annual total P. viticola spores quantity was observed in 2010 (1,548 spores) and the lowest in 2005 (210 spores). In order to forecast the concentration of fungal spores, ARIMA models were elaborated. The most accurate models were an ARIMA (3.1.3) for U. necator and (1.0.3) for P. viticola. The possibility to forecast the spore presence 72 hours in advance open an important horizon for optimizing the organization of the harvest processes in the vineyard.

  14. Modelling

    CERN Document Server

    Spädtke, P

    2013-01-01

    Modeling of technical machines became a standard technique since computer became powerful enough to handle the amount of data relevant to the specific system. Simulation of an existing physical device requires the knowledge of all relevant quantities. Electric fields given by the surrounding boundary as well as magnetic fields caused by coils or permanent magnets have to be known. Internal sources for both fields are sometimes taken into account, such as space charge forces or the internal magnetic field of a moving bunch of charged particles. Used solver routines are briefly described and some bench-marking is shown to estimate necessary computing times for different problems. Different types of charged particle sources will be shown together with a suitable model to describe the physical model. Electron guns are covered as well as different ion sources (volume ion sources, laser ion sources, Penning ion sources, electron resonance ion sources, and H$^-$-sources) together with some remarks on beam transport.

  15. Modeling the effects of environmental disturbance on wildlife communities: Avian responses to prescribed fire

    Science.gov (United States)

    Russell, R.E.; Royle, J. Andrew; Saab, V.A.; Lehmkuhl, J.F.; Block, W.M.; Sauer, J.R.

    2009-01-01

    Prescribed fire is a management tool used to reduce fuel loads on public lands in forested areas in the western United States. Identifying the impacts of prescribed fire on bird communities in ponderosa pine (Pinus ponderosa) forests is necessary for providing land management agencies with information regarding the effects of fuel reduction on sensitive, threatened, and migratory bird species. Recent developments in occupancy modeling have established a framework for quantifying the impacts of management practices on wildlife community dynamics. We describe a Bayesian hierarchical model of multi-species occupancy accounting for detection probability, and we demonstrate the model's usefulness for identifying effects of habitat disturbances on wildlife communities. Advantages to using the model include the ability to estimate the effects of environmental impacts on rare or elusive species, the intuitive nature of the modeling, the incorporation of detection probability, the estimation of parameter uncertainty, the flexibility of the model to suit a variety of experimental designs, and the composite estimate of the response that applies to the collection of observed species as opposed to merely a small subset of common species. Our modeling of the impacts of prescribed fire on avian communities in a ponderosa pine forest in Washington indicate that prescribed fire treatments result in increased occupancy rates for several bark-insectivore, cavity-nesting species including a management species of interest, Black-backed Woodpeckers (Picoides arcticus). Three aerial insectivore species, and the ground insectivore, American Robin (Turdus migratorius), also responded positively to prescribed fire, whereas three foliage insectivores and two seed specialists, Clark's Nutcracker (Nucifraga columbiana) and the Pine Siskin (Carduelis pinus), declined following treatments. Land management agencies interested in determining the effects of habitat manipulations on wildlife

  16. Modeling the effects of environmental disturbance on wildlife communities: avian responses to prescribed fire.

    Science.gov (United States)

    Russell, Robin E; Royle, J Andrew; Saab, Victoria A; Lehmkuhl, John F; Block, William M; Sauer, John R

    2009-07-01

    Prescribed fire is a management tool used to reduce fuel loads on public lands in forested areas in the western United States. Identifying the impacts of prescribed fire on bird communities in ponderosa pine (Pinus ponderosa) forests is necessary for providing land management agencies with information regarding the effects of fuel reduction on sensitive, threatened, and migratory bird species. Recent developments in occupancy modeling have established a framework for quantifying the impacts of management practices on wildlife community dynamics. We describe a Bayesian hierarchical model of multi-species occupancy accounting for detection probability, and we demonstrate the model's usefulness for identifying effects of habitat disturbances on wildlife communities. Advantages to using the model include the ability to estimate the effects of environmental impacts on rare or elusive species, the intuitive nature of the modeling, the incorporation of detection probability, the estimation of parameter uncertainty, the flexibility of the model to suit a variety of experimental designs, and the composite estimate of the response that applies to the collection of observed species as opposed to merely a small subset of common species. Our modeling of the impacts of prescribed fire on avian communities in a ponderosa pine forest in Washington indicate that prescribed fire treatments result in increased occupancy rates for several bark-insectivore, cavity-nesting species including a management species of interest, Black-backed Woodpeckers (Picoides arcticus). Three aerial insectivore species, and the ground insectivore, American Robin (Turdus migratorius), also responded positively to prescribed fire, whereas three foliage insectivores and two seed specialists, Clark's Nutcracker (Nucifraga columbiana) and the Pine Siskin (Carduelis pinus), declined following treatments. Land management agencies interested in determining the effects of habitat manipulations on wildlife

  17. Habitat Evaluation Procedures (HEP) Report : Hellsgate Project, 1999-2000 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Matthew

    2000-05-01

    A Habitat Evaluation Procedure (HEP) study was conducted on lands acquired and/or managed (4,568 acres total) by the Hellsgate Big Game Winter Range Wildlife Mitigation Project (Hellsgate project) to mitigate some of the losses associated with the original construction and operation of Grand Coulee Dam and inundation of habitats behind the dams. Three separate properties, totaling 2,224 acres were purchased in 1998. One property composed of two separate parcels, mostly grassland lies southeast of the town of Nespelem in Okanogan County (770 acres) and was formerly called the Hinman property. The former Hinman property lies within an area the Tribes have set aside for the protection and preservation of the sharp-tailed grouse (Agency Butte unit). This special management area minus the Hinman acquisition contains 2,388 acres in a long-term lease with the Tribes. The second property lies just south of the Silver Creek turnoff (Ferry County) and is bisected by the Hellsgate Road (part of the Friedlander unit). This parcel contains 60 acres of riparian and conifer forest cover. The third property (now named the Sand Hills unit) acquired for mitigation (1,394 acres) lies within the Hellsgate Reserve in Ferry County. This new acquisition links two existing mitigation parcels (the old Sand Hills parcels and the Lundstrum Flat parcel, all former Kuehne purchases) together forming one large unit. HEP team members included individuals from the Colville Confederated Tribes Fish and Wildlife Department (CTCR), Washington Department of Fish and Wildlife (WDFW), and Bureau of Land Management (BLM). The HEP team conducted a baseline habitat survey using the following HEP species models: mule deer (Odocoileus hemionus), mink (Mustela vison), downy woodpecker (Picoides pubescens), bobcat (Lynx rufus), yellow warbler (Dendroica petechia), and sharp-tailed grouse (Tympanuchus phasianellus columbianus). HEP analysis and results are discussed within the body of the text. The cover types

  18. Focus expansion and stability of the spread parameter estimate of the power law model for dispersal gradients.

    Science.gov (United States)

    Ojiambo, Peter S; Gent, David H; Mehra, Lucky K; Christie, David; Magarey, Roger

    2017-01-01

    Empirical and mechanistic modeling indicate that pathogens transmitted via aerially dispersed inoculum follow a power law, resulting in dispersive epidemic waves. The spread parameter ( b ) of the power law model, which is an indicator of the distance of the epidemic wave front from an initial focus per unit time, has been found to be approximately 2 for several animal and plant diseases over a wide range of spatial scales under conditions favorable for disease spread. Although disease spread and epidemic expansion can be influenced by several factors, the stability of the parameter b over multiple epidemic years has not been determined. Additionally, the size of the initial epidemic area is expected to be strongly related to the final epidemic extent for epidemics, but the stability of this relationship is also not well established. Here, empirical data of cucurbit downy mildew epidemics collected from 2008 to 2014 were analyzed using a spatio-temporal model of disease spread that incorporates logistic growth in time with a power law function for dispersal. Final epidemic extent ranged from 4.16 ×10 8 km 2 in 2012 to 6.44 ×10 8 km 2 in 2009. Current epidemic extent became significantly associated ( P  power law model. These results suggest that the spread parameter b may not be stable over multiple epidemic years. However, b  ≈ 2 may be considered the lower limit of the distance traveled by epidemic wave-fronts for aerially transmitted pathogens that follow a power law dispersal function.

  19. Mapping and spatial-temporal modeling of Bromus tectorum invasion in central Utah

    Science.gov (United States)

    Jin, Zhenyu

    Cheatgrass, or Downy Brome, is an exotic winter annual weed native to the Mediterranean region. Since its introduction to the U.S., it has become a significant weed and aggressive invader of sagebrush, pinion-juniper, and other shrub communities, where it can completely out-compete native grasses and shrubs. In this research, remotely sensed data combined with field collected data are used to investigate the distribution of the cheatgrass in Central Utah, to characterize the trend of the NDVI time-series of cheatgrass, and to construct a spatially explicit population-based model to simulate the spatial-temporal dynamics of the cheatgrass. This research proposes a method for mapping the canopy closure of invasive species using remotely sensed data acquired at different dates. Different invasive species have their own distinguished phenologies and the satellite images in different dates could be used to capture the phenology. The results of cheatgrass abundance prediction have a good fit with the field data for both linear regression and regression tree models, although the regression tree model has better performance than the linear regression model. To characterize the trend of NDVI time-series of cheatgrass, a novel smoothing algorithm named RMMEH is presented in this research to overcome some drawbacks of many other algorithms. By comparing the performance of RMMEH in smoothing a 16-day composite of the MODIS NDVI time-series with that of two other methods, which are the 4253EH, twice and the MVI, we have found that RMMEH not only keeps the original valid NDVI points, but also effectively removes the spurious spikes. The reconstructed NDVI time-series of different land covers are of higher quality and have smoother temporal trend. To simulate the spatial-temporal dynamics of cheatgrass, a spatially explicit population-based model is built applying remotely sensed data. The comparison between the model output and the ground truth of cheatgrass closure demonstrates

  20. Columbia River wildlife mitigation habitat evaluation procedures report: Scotch Creek Wildlife Area, Berg Brothers, and Douglas County pygmy rabbit projects

    International Nuclear Information System (INIS)

    Ashley, P.R.; Ratassepp, J.; Berger, M.; Judd, S.L.

    1997-01-01

    This Habitat Evaluation Procedure study was conducted to determine baseline habitat units (HUs) on the Scotch Creek, Mineral Hill, Pogue Mountain, Chesaw and Tunk Valley Habitat Areas (collectively known as the Scotch Creek Wildlife Area) in Okanogan County, Sagebrush Flat and the Dormaler property in Douglas County, and the Berg Brothers ranch located in Okanogan County within the Colville Reservation. A HEP team comprised of individuals from the Washington Department of Fish and Wildlife, the Confederated Tribes of the Colville Reservation, and the Natural Resources Conservation Service (Appendix A) conducted baseline habitat surveys using the following HEP evaluation species: mule deer (Odocoileus hemionus), sharp-tailed grouse (Tympanuchus phasianellus), pygmy rabbit (Brachylagus idahoensis), white-tailed deer (Odocoileus virginiana), mink (Mustela vison), Canada goose (Branta canadensis), downy woodpecker (Picoides pubescens), Lewis woodpecker (Melanerpes lewis), and Yellow warbler (Dendroica petechia). Results of the HEP analysis are listed below. General ratings (poor, marginal, fair, etc.,) are described in Appendix B. Mule deer habitat was marginal lacking diversity and quantify of suitable browse species. Sharp-tailed grouse habitat was marginal lacking residual nesting cover and suitable winter habitat Pygmy rabbit habitat was in fair condition except for the Dormaier property which was rated marginal due to excessive shrub canopy closure at some sites. This report is an analysis of baseline habitat conditions on mitigation project lands and provides estimated habitat units for mitigation crediting purposes. In addition, information from this document could be used by wildlife habitat managers to develop management strategies for specific project sites

  1. Columbia River Wildlife Mitigation Habitat Evaluation Procedures Report / Scotch Creek Wildlife Area, Berg Brothers, and Douglas County Pygmy Rabbit Projects.

    Energy Technology Data Exchange (ETDEWEB)

    Ashley, Paul R.

    1997-01-01

    This Habitat Evaluation Procedure study was conducted to determine baseline habitat units (HUs) on the Scotch Creek, Mineral Hill, Pogue Mountain, Chesaw and Tunk Valley Habitat Areas (collectively known as the Scotch Creek Wildlife Area) in Okanogan County, Sagebrush Flat and the Dormaler property in Douglas County, and the Berg Brothers ranch located in Okanogan County within the Colville Reservation. A HEP team comprised of individuals from the Washington Department of Fish and Wildlife, the Confederated Tribes of the Colville Reservation, and the Natural Resources Conservation Service (Appendix A) conducted baseline habitat surveys using the following HEP evaluation species: mule deer (Odocoileus hemionus), sharp-tailed grouse (Tympanuchus phasianellus), pygmy rabbit (Brachylagus idahoensis), white-tailed deer (Odocoileus virginiana), mink (Mustela vison), Canada goose (Branta canadensis), downy woodpecker (Picoides pubescens), Lewis woodpecker (Melanerpes lewis), and Yellow warbler (Dendroica petechia). Results of the HEP analysis are listed below. General ratings (poor, marginal, fair, etc.,) are described in Appendix B. Mule deer habitat was marginal lacking diversity and quantify of suitable browse species. Sharp-tailed grouse habitat was marginal lacking residual nesting cover and suitable winter habitat Pygmy rabbit habitat was in fair condition except for the Dormaier property which was rated marginal due to excessive shrub canopy closure at some sites. This report is an analysis of baseline habitat conditions on mitigation project lands and provides estimated habitat units for mitigation crediting purposes. In addition, information from this document could be used by wildlife habitat managers to develop management strategies for specific project sites.

  2. Habitat Evaluation Procedures (HEP) Report; Iskuulpa Wildlife Mitigation and Watershed Project, Technical Report 1998-2003.

    Energy Technology Data Exchange (ETDEWEB)

    Quaempts, Eric

    2003-01-01

    U.S. Fish and Wildlife Service (USFWS) Habitat Evaluation Procedures (HEP) were used to determine the number of habitat units credited to evaluate lands acquired and leased in Eskuulpa Watershed, a Confederated Tribes of the Umatilla Indian Reservation watershed and wildlife mitigation project. The project is designed to partially credit habitat losses incurred by BPA for the construction of the John Day and McNary hydroelectric facilities on the Columbia River. Upland and riparian forest, upland and riparian shrub, and grasslands cover types were included in the evaluation. Indicator species included downy woodpecker (Picuides puhescens), black-capped chickadee (Pams atricopillus), blue grouse (Beadragapus obscurus), great blue heron (Ardea herodias), yellow warbler (Dendroica petschia), mink (Mustela vison), and Western meadowlark (Sturnello neglects). Habitat surveys were conducted in 1998 and 1999 in accordance with published HEP protocols and included 55,500 feet of transects, 678 m2 plots, and 243 one-tenth-acre plots. Between 123.9 and f 0,794.4 acres were evaluated for each indicator species. Derived habitat suitability indices were multiplied by corresponding cover-type acreages to determine the number of habitat units for each species. The total habitat units credited to BPA for the Iskuulpa Watershed Project and its seven indicator species is 4,567.8 habitat units. Factors limiting habitat suitability are related to the direct, indirect, and cumulative effects of past livestock grazing, road construction, and timber harvest, which have simplified the structure, composition, and diversity of native plant communities. Alternatives for protecting and improving habitat suitability include exclusion of livestock grazing or implementation of restoration grazing schemes, road de-commissioning, reforestation, large woody debris additions to floodplains, control of competing and unwanted vegetation, reestablishing displaced or reduced native vegetation species

  3. First Report of Peronospora digitalidis causing downy mildew disease on foxglove in Oregon

    Science.gov (United States)

    Foxglove (Digitalis purpurea) is a biennial plant in the Plantaginaceae family. Widely cultivated as a striking flowering ornamental plant, foxglove is also a source of toxic cardiac glycosides that may be fatal if ingested at high doses, or used pharmaceutically to treat human heart failure. In the...

  4. Downy mildew of Double Knock Out® rose caused by Peronospora sparsa in Maryland

    Science.gov (United States)

    Roses are one of the most popular and economically important ornamental plants worldwide. In the last 17 years, Knock Out® roses (Rosa x 'Radtko') have been widely used in public and private gardens across the U.S. due to their disease resistance, self-cleaning, drought tolerance and multiple-bloomi...

  5. Risk assessment: progress of quarantine biocontrol research on Chinese Tallow, Melaleuca, and Downy Rose Myrtle

    Science.gov (United States)

    Risk assessments of two biocontrol candidates for Chinese tallow, Triadica sebifera (Euphoriales: Euphorbiaceae), and one for Melaleuca, Melaleuca quinquenervia (Myrtales: Myrtaceae), were conducted during 2009 and continuing into 2010 by USDA scientists located at the Florida Department of Agricul...

  6. Molecular aspects of plant disease susceptibility: Arabidopsis genes affecting downy mildew infection

    NARCIS (Netherlands)

    Lapin, D.

    2013-01-01

    Interactions of plants with pathogenic microorganisms are influenced by multiple biotic and abiotic factors. The host immune system can detect pathogens and restrict their growth and development, but also non-immunity related host factors and processes can contribute to pathogenesis by attracting

  7. State of sorghum downy mildew in maize in the Sudan and sahel ...

    African Journals Online (AJOL)

    2008 growing season following a planned–two time survey across the Sudan and the Sahel savanna agro-ecological zones of Nigeria. The occurrence of the disease was investigated in 102 and 120 farmers' fields in 34 and 40 locations in the first and second surveys respectively. Average incidence (%) of the disease was ...

  8. Enhanced fire-related traits may contribute to the invasiveness of Downy Brome (Bromus tectorum)

    Science.gov (United States)

    Although several invasive species have induced changes to the fire regime of invaded ecosystems, potential intraspecific shifts in fire-related traits that might enhance their invasion success, have never been addressed. We assumed that traits conferring persistence and competitiveness in post-fire ...

  9. Effects of growth regulator herbicide on downy brome (Bromus tectorum) seed production

    Science.gov (United States)

    Previous research showed growth regulator herbicides, such as picloram and aminopyralid, have a sterilizing effect on Japanese brome (Bromus japonicus Thunb.) that can reduce this invasive annual grass’s seed production nearly 100%. This suggests growth regulators might be used to control invasive ...

  10. Suppression of downy brome by red clover as a cover crop

    Science.gov (United States)

    Weeds are one of the primary obstacles to successful organic farming. Organic producers till to control weeds, but soil health is being damaged by the extensive tillage. Therefore, organic producers are interested in reducing the amount of tillage in their production systems. This study examined t...

  11. Downy brome control and impacts on perennial grass abundance: a systematic review spanning 64 years

    Science.gov (United States)

    Given the high cost of restoration and the underlying assumption that reducing annual grass abundance is a necessary precursor to rangeland restoration in the Intermountain West, USA, we sought to identify limitations and strengths of annual grass and woody plant reduction methods and refine future ...

  12. Leg deformation during imaginal ecdysis in the downy emerald, Cordulia aenea (Odonata, Corduliidae).

    Science.gov (United States)

    Frantsevich, Leonid; Frantsevich, Ludmilla

    2018-04-01

    A dragonfly larva migrates from the water to the shore, perches on a plant stem and grasps it with strongly flexed legs. Adult legs inside the larval exoskeleton fit to the larval legs joint-to-joint. The adult emerges with stretched legs. During the molt, an imaginal leg must follow all the angles in exuvial joints. In turn, larval apodemes are withdrawn from imaginal legs. We visualized transient shapes of the imaginal legs by the instant fixation of insects at different moments of the molt, photographed isolated exuvial legs with the imaginal legs inside and then removed the exuvial sheath. Instant shapes of the imaginal tibia show sharp intrapodomere bends copying the angle in the larval femoro-tibial joint. The site of bending shifts distad during the molt. This is possible if the imaginal leg is pliable. The same problem of leg squeezing is also common in hemimetabolous insects as well as in other arthropods, whereas holometabolous insects overcome problems of a tight confinement either by using leg pliability in other ways but not squeezing (cyclorrhaphan flies, mosquitoes) or by pulling hardened legs out without change of their pupal zigzag configuration (moths, ants, honey bees). The pupal legs are not intended to grasp any external substrate. Copyright © 2018 Elsevier GmbH. All rights reserved.

  13. Incorporation of temperature and solar radiation thresholds to modify a lettuce downy mildew warning system

    NARCIS (Netherlands)

    Wu, B.M.; Bruggen, van A.H.C.; Subbarao, K.V.; Scherm, H.

    2002-01-01

    The effect of temperature on infection of lettuce by Bremia lactucae was investigated in controlled environment studies and in the field. In controlled conditions, lettuce seedlings inoculated with B. lactucae were incubated at 15, 20, 25, or 30°C during a 4-h wet period immediately after

  14. OUTBREAK OF MAIZE DOWNY MILDEW (Sclerophthora macrospora IN SLOVENIA IN 1999

    Directory of Open Access Journals (Sweden)

    Stanislav Trdan

    2000-12-01

    Full Text Available In 1999 a pronounced infection of maize with fungus Sclerophthora macrospora occurred in Slovenia, especially in its north-eastern and eastern regions. Symptoms, typical for infection with this fungus, were found on app. 1800 ha, which means on about 2.5 % of the acreage on which maize is grown. The infected plants were found only on those fields, or parts of those fields, which were flooded for some time soon after sowing or emergence of the crop. The percentage of the plants infected by the fungus was between 5 and 90 %, depending on the type of soil. This article presents different disease causing fungi, their taxonomy, and deals in detail with the species Sclerophthora macrospora, the only disease causing organism under our growing conditions. The article deals with hosts of the fungus, typical symptoms of the disease on maize (“crazy top”, pathogen biology, the mode of infection, its survival under unfavorable conditions, and possible protection against the infection. The article also describes the actual situation in Slovenia, and adds a comment on possible regular occurrences of this disease in future.

  15. Molecular approaches for biosurveillance of the cucurbit downy mildew pathogen, Pseudoperonospora cubensis

    Science.gov (United States)

    Globalization has allowed for rapid movement of plant pathogens that threaten food security. Successful disease management largely depends in timely and accurate detection of plant pathogens causing epidemics. Thus, biosurveillance of epidemic plant pathogens such as Pseudoperonospora cubensis, the ...

  16. state of sorghum downy mildew in maize in the sudan and sahel ...

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... Southern guinea savanna and the forest zones of. Nigeria where the mean annual rainfall was 1200-. 1800 mm (Olanya et al., 1993, Bock, 1995). However, maize plants infected with sorghum/maize strains were found only in the Northern guinea savannah zone where mean annual rainfall was 1200-1300 ...

  17. Focus expansion and stability of the spread parameter estimate of the power law model for dispersal gradients

    Directory of Open Access Journals (Sweden)

    Peter S. Ojiambo

    2017-06-01

    Full Text Available Empirical and mechanistic modeling indicate that pathogens transmitted via aerially dispersed inoculum follow a power law, resulting in dispersive epidemic waves. The spread parameter (b of the power law model, which is an indicator of the distance of the epidemic wave front from an initial focus per unit time, has been found to be approximately 2 for several animal and plant diseases over a wide range of spatial scales under conditions favorable for disease spread. Although disease spread and epidemic expansion can be influenced by several factors, the stability of the parameter b over multiple epidemic years has not been determined. Additionally, the size of the initial epidemic area is expected to be strongly related to the final epidemic extent for epidemics, but the stability of this relationship is also not well established. Here, empirical data of cucurbit downy mildew epidemics collected from 2008 to 2014 were analyzed using a spatio-temporal model of disease spread that incorporates logistic growth in time with a power law function for dispersal. Final epidemic extent ranged from 4.16 ×108 km2 in 2012 to 6.44 ×108 km2 in 2009. Current epidemic extent became significantly associated (P < 0.0332; 0.56 < R2 < 0.99 with final epidemic area beginning near the end of April, with the association increasing monotonically to 1.0 by the end of the epidemic season in July. The position of the epidemic wave-front became exponentially more distant with time, and epidemic velocity increased linearly with distance. Slopes from the temporal and spatial regression models varied with about a 2.5-fold range across epidemic years. Estimates of b varied substantially ranging from 1.51 to 4.16 across epidemic years. We observed a significant b ×time (or distance interaction (P < 0.05 for epidemic years where data were well described by the power law model. These results suggest that the spread parameter b may not be stable over multiple epidemic

  18. Habitat Evaluation Procedures (HEP) Report; Precious Lands Wildlife Management Area, Technical Report 2000-2003.

    Energy Technology Data Exchange (ETDEWEB)

    Kozusko, Shana

    2003-12-01

    The Nez Perce Tribe (NPT) currently manages a 15,325 acre parcel of land known as the Precious Lands Wildlife Management Area that was purchased as mitigation for losses incurred by construction of the four lower Snake River dams. The Management Area is located in northern Wallowa County, Oregon and southern Asotin County, Washington (Figure 1). It is divided into three management parcels--the Buford parcel is located on Buford Creek and straddles the WA-OR state line, and the Tamarack and Basin parcels are contiguous to each other and located between the Joseph Creek and Cottonwood Creek drainages in Wallowa County, OR. The project was developed under the Pacific Northwest Electric Power Planning and Conservation Act of 1980 (P.L. 96-501), with funding from the Bonneville Power Administration (BPA). The acreage protected under this contract will be credited to BPA as habitat permanently dedicated to wildlife and wildlife mitigation. A modeling strategy known as Habitat Evaluation Procedure (HEP) was developed by the U.S. Fish and Wildlife Service and adopted by BPA as a habitat equivalency accounting system. Nine wildlife species models were used to evaluate distinct cover type features and provide a measure of habitat quality. Models measure a wide range of life requisite variables for each species and monitor overall trends in vegetation community health and diversity. One product of HEP is an evaluation of habitat quality expressed in Habitat Units (HUs). This HU accounting system is used to determine the amount of credit BPA receives for mitigation lands. After construction of the four lower Snake River dams, a HEP loss assessment was conducted to determine how many Habitat Units were inundated behind the dams. Twelve target species were used in that evaluation: Canada goose, mallard, river otter, downy woodpecker, song sparrow, yellow warbler, marsh wren, western meadowlark, chukar, ring-necked pheasant, California quail, and mule deer. The U.S. Army Corp of

  19. Using an agent-based model to examine forest management outcomes in a fire-prone landscape in Oregon, USA

    Directory of Open Access Journals (Sweden)

    Thomas A. Spies

    2017-03-01

    Full Text Available Fire-prone landscapes present many challenges for both managers and policy makers in developing adaptive behaviors and institutions. We used a coupled human and natural systems framework and an agent-based landscape model to examine how alternative management scenarios affect fire and ecosystem services metrics in a fire-prone multiownership landscape in the eastern Cascades of Oregon. Our model incorporated existing models of vegetation succession and fire spread and information from original empirical studies of landowner decision making. Our findings indicate that alternative management strategies can have variable effects on landscape outcomes over 50 years for fire, socioeconomic, and ecosystem services metrics. For example, scenarios with federal restoration treatments had slightly less high-severity fire than a scenario without treatment; exposure of homes in the wildland-urban interface to fire was also slightly less with restoration treatments compared to no management. Treatments appeared to be more effective at reducing high-severity fire in years with more fire than in years with less fire. Under the current management scenario, timber production could be maintained for at least 50 years on federal lands. Under an accelerated restoration scenario, timber production fell because of a shortage of areas meeting current stand structure treatment targets. Trade-offs between restoration outcomes (e.g., open forests with large fire-resistant trees and habitat for species that require dense older forests were evident. For example, the proportional area of nesting habitat for northern spotted owl (Strix occidentalis was somewhat less after 50 years under the restoration scenarios than under no management. However, the amount of resilient older forest structure and habitat for white-headed woodpecker (Leuconotopicus albolarvatus was higher after 50 years under active management. More carbon was stored on this landscape without management than

  20. Effects of radio transmitters on the behavior of Red-headed Woodpeckers

    Science.gov (United States)

    Mark Vukovich; John C. Kilgo

    2009-01-01

    Previous studies have revealed that radio-transmitters may affect bird behaviors, including feeding rates, foraging behavior, vigilance, and preening behavior. In addition, depending on the method of attachment, transmitters can potentially affect the ability of cavity-nesting birds to use cavities. Our objective was to evaluate effects of transmitters on the behavior...

  1. Woodpecker use and fall rates of snags created by killing ponderosa pine infected with dwarf mistletoe.

    Science.gov (United States)

    Catherine G. Parks; David A. Conklin; Larry Bednar; Helen. Maffei

    1999-01-01

    Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) killed as part of a forest management project to reduce dwarf mistletoe (Arceuthobium sp.) in the Gila National Forest, New Mexico, were evaluated for wildlife value. One hundred and two dwarf mistletoe-infected trees were killed by basal burning, basal girdling, or by a...

  2. 75 FR 41886 - Recovery Plan for the Ivory-billed Woodpecker (Campephilus principalis)

    Science.gov (United States)

    2010-07-19

    ... ecosystems is a primary goal of our threatened and endangered species program. To help guide the recovery... focuses on learning more about the species' status and ecology, including documenting known locations and.... Analyze viability of any existing populations (numbers, breeding success, population genetics, and ecology...

  3. Scientific Method & Evolutionary Theory Elucidated by the Ivory-Billed Woodpecker Story

    Science.gov (United States)

    Krupa, James J.

    2014-01-01

    Large, introductory, nonmajors biology classes present challenges when trying to encourage class discussion to help reinforce important concepts. Lively in-class discussion involving hundreds of students is more successful when a relevant story told with passion is used to introduce a topic. In my courses, each semester begins with thorough…

  4. An Exploration of the Effects of Genetic Drift on the Endangered Red-Cockaded Woodpecker

    Science.gov (United States)

    2006-03-01

    catkin and conelet production must coincide to successfully reproduce pinecones (Boyer, 1990). Longleaf pine begins producing pinecones from 20 to...30 years of age (Michigan Tech University, 2003). The pinecone may contain 15 to 50 seeds (Boyer, 1990). After reaching maturity, the pinecone ... pinecones will not develop until the end of the third growing season (Lawson, 1990). Although some abnormal cases exist, shortleaf pine does not bear

  5. Apparent foraging success reflects habitat quality in an irruptive species, the Black-backed Woodpecker

    Science.gov (United States)

    Christopher T. Rota; Mark A. Rumble; Chad P. Lehman; Dylan C. Kesler; Joshua J. Millspaugh

    2015-01-01

    Dramatic fluctuations in food resources are a key feature of many habitats, and many species have evolved a movement strategy to exploit food resources that are unpredictable in space and time. The availability of food resources may be a particularly strong determinant of habitat quality for irruptive bird species. We studied the apparent foraging success of Black-...

  6. Modeling ecotoxicity impacts in vineyard production: Addressing spatial differentiation for copper fungicides

    DEFF Research Database (Denmark)

    Peña, Nancy; Antón, Assumpció; Kamilaris, Andreas

    2018-01-01

    the toxicity-related characterization of copper-based fungicides (Cu) for LCA studies. Potential freshwater ecotoxicity impacts of 12 active ingredients used to control downy mildew in European vineyards were quantified and compared. Soil ecotoxicity impacts were calculated for specific soil chemistries...... the 12 studied active ingredients. With the inclusion of spatial differentiation, Cu toxicity potentials vary 3 orders of magnitude, making variation according to water archetypes potentially relevant. In the case of non-calcareous soils ecotoxicity characterization, the variability of Cu impacts...

  7. Behavioral evidence for fruit odor discrimination and sympatric host races of Rhagoletis pomonella flies in the western United States

    Science.gov (United States)

    The recent shift of Rhagoletis pomonella (Diptera: Tephritidae) from its native host downy hawthorn, Crataegus mollis, to introduced domesticated apple, Malus domestica, in the eastern U.S. is a model for sympatric host race formation. However, the fly is also present in the western U.S. where it ma...

  8. Model(ing) Law

    DEFF Research Database (Denmark)

    Carlson, Kerstin

    The International Criminal Tribunal for the former Yugoslavia (ICTY) was the first and most celebrated of a wave of international criminal tribunals (ICTs) built in the 1990s designed to advance liberalism through international criminal law. Model(ing) Justice examines the case law of the ICTY...

  9. Models and role models

    NARCIS (Netherlands)

    ten Cate, J.M.

    2015-01-01

    Developing experimental models to understand dental caries has been the theme in our research group. Our first, the pH-cycling model, was developed to investigate the chemical reactions in enamel or dentine, which lead to dental caries. It aimed to leverage our understanding of the fluoride mode of

  10. First report of Peronospora sp. causing downy mildew disease on Geum sp. in the northeastern United States

    Science.gov (United States)

    Plants in the genus Geum are clump-forming perennials in the family Rosaceae. Known for long bloom times and the ability to attract pollinators, Geum hybrids are popular ornamental plants commonly grown in borders and rock gardens (Brickell & Cathey, 2004). In early April 2017, the entire crop of Ge...

  11. Raw hulled shredded acorns from Downy Oak (Quercus pubescens) in the diet of pigs: effects on digestibility and faeces characteristics.

    Science.gov (United States)

    Cappai, M G; Wolf, P; Rust, P; Pinna, W; Kamphues, J

    2013-05-01

    Faeces quality and composition are both of interest to veterinary practitioners dealing with pigs' health and disturbances in the alimentary tract, especially in free-range situations. In the Mediterranean basin, acorns are used as a starch source for fattening pigs, yet little information is available on how that affects faecal quality and digestibility. Therefore, a combined diet containing ripe hulled shredded acorns vs. a pelleted complete diet for finishers was evaluated for the digestibility and faecal consistency. The trial involved eight crossbred pigs, and a matched-pair approach was used to divide animals into two groups, which were fed with two different diets: acorns group (A): n = 4, 70% ripe hulled shredded acorns + 30% pelleted complete diet combined, as fed; control group (C): n = 4, 100% pelleted complete feed. The pigs were housed individually and fed the experimental diets for 8 days; daily feed intake and faeces amounts were recorded and faeces quality assessed. The digestibility of organic matter (OM) and starch of the two diets, as well as of pure acorns, were calculated and compared. Daily feed consumption was significantly higher in group A, but the mean dry matter intake (DMI) per pig was similar in both groups. Dark, firm and consistent faeces were reported for each pig from group A in comparison with group B, whose faeces were paler and softer. Digestibility of OM and starch were lower in group A than in group B (67.8 ± 3.4 vs. 83.9 ± 1.1 and 82.5 ± 3.4 vs. 92.3 ± 2.1 respectively): total tract digestibility of native starch from pure acorns was calculated at 77%. The peculiar consistency of faeces was related to macroscopic acorn hulls, constantly detected in the faeces of all animals sampled in group A. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

  12. First report of Ser653Asn mutation endowing high-level resistance to imazamox in downy brome (Bromus tectorum L.).

    Science.gov (United States)

    Kumar, Vipan; Jha, Prashant

    2017-12-01

    Bromus tectorum L. is one of the most troublesome grass weed species in cropland and non-cropland areas of the northwestern USA. In summer 2016, a B. tectroum accession (R) that survived imazamox at the field-use rate (44 g ha -1 ) in an imidazolinone-tolerant (IMI-tolerant or Clearfield™) winter wheat field was collected from a wheat field in Carter County, MT, USA. The aim of this study was to determine the resistance profile of the B. tectroum R accession to imazamox and other ALS inhibitors, and investigate the mechanism of resistance to imazamox. The R B. tectorum accession had a high-level resistance (110.1-fold) to imazamox (IMI) and low to moderate-levels cross-resistance to pyroxsulam (TP) (4.6-fold) and propoxycarbazone (SCT) (13.9-fold). The R accession was susceptible to sulfosulfuron (SU) and quizalofop and clethodim (ACCase inhibitors), paraquat (PS I inhibitor), glyphosate (EPSPS inhibitor) and glufosinate (GS inhibitor). Sequence analysis of the ALS gene revealed a single, target-site Ser653Asn mutation in R plants. Pretreatment of malathion followed by imazamox at 44 or 88 g ha -1 did not reverse the resistance phenotype. This is the first report of evolution of cross-resistance to ALS-inhibiting herbicides in B. tectorum. A single-point mutation, Ser653Asn, was identified, conferring the high-level resistance to imazamox. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Distribution of downy mildew (Bremia Lactucae Regel) resistances in a genebank collection of lettuce and its wild relatives

    NARCIS (Netherlands)

    Treuren, van R.; Arend, van der A.J.M.; Schut, J.W.

    2013-01-01

    Genebanks serve as a rich source of diversity that can be exploited for crop improvement. However, large numbers of accessions usually have to be evaluated to find material with the characters of interest, and therefore, enhanced trait information can facilitate the more efficient selection of

  14. Computing Integrated Ratings from Heterogeneous Phenotypic Assessments: A Case Study of Lettuce Postharvest Quality and Downy Mildew Resistance

    Science.gov (United States)

    Comparing performance of a large number of accessions simultaneously is not always possible. Typically, only subsets of all accessions are tested in separate trials with only some (or none) of the accessions overlapping between subsets. Using standard statistical approaches to combine data from such...

  15. Additions to the Ethiopian bird atlas: 126 new records from 14 atlas ...

    African Journals Online (AJOL)

    Brown (Meyer's) Parrot Poicephalus meyeri. Seen or heard daily in open woodland and riverine forest ... Grey Woodpecker (Grey-headed Woodpecker) Dendropicos (goertae) spodocephalus. Ash & Atkins (2009) treats African Grey Woodpecker D. goertae and Grey-headed. Woodpecker D. spodocephalus as conspecific.

  16. Cognitive modeling

    OpenAIRE

    Zandbelt, Bram

    2017-01-01

    Introductory presentation on cognitive modeling for the course ‘Cognitive control’ of the MSc program Cognitive Neuroscience at Radboud University. It addresses basic questions, such as 'What is a model?', 'Why use models?', and 'How to use models?'

  17. Modelling the models

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    By analysing the production of mesons in the forward region of LHC proton-proton collisions, the LHCf collaboration has provided key information needed to calibrate extremely high-energy cosmic ray models.   Average transverse momentum (pT) as a function of rapidity loss ∆y. Black dots represent LHCf data and the red diamonds represent SPS experiment UA7 results. The predictions of hadronic interaction models are shown by open boxes (sibyll 2.1), open circles (qgsjet II-03) and open triangles (epos 1.99). Among these models, epos 1.99 shows the best overall agreement with the LHCf data. LHCf is dedicated to the measurement of neutral particles emitted at extremely small angles in the very forward region of LHC collisions. Two imaging calorimeters – Arm1 and Arm2 – take data 140 m either side of the ATLAS interaction point. “The physics goal of this type of analysis is to provide data for calibrating the hadron interaction models – the well-known &...

  18. Modelling Practice

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    This chapter deals with the practicalities of building, testing, deploying and maintaining models. It gives specific advice for each phase of the modelling cycle. To do this, a modelling framework is introduced which covers: problem and model definition; model conceptualization; model data...... requirements; model construction; model solution; model verification; model validation and finally model deployment and maintenance. Within the adopted methodology, each step is discussedthrough the consideration of key issues and questions relevant to the modelling activity. Practical advice, based on many...... years of experience is providing in directing the reader in their activities.Traps and pitfalls are discussed and strategies also given to improve model development towards “fit-for-purpose” models. The emphasis in this chapter is the adoption and exercise of a modelling methodology that has proven very...

  19. Habitat Evaluation Procedures (HEP) Report : Rainwater Wildlife Area, 1998-2001 Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Childs, Allen

    2004-01-01

    The 8,768 acre Rainwater Wildlife Area was acquired in September 1998 by the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) through an agreement with Bonneville Power Administration (BPA) to partially offset habitat losses associated with construction of the John Day and McNary hydroelectric facilities on the mainstem Columbia River. U.S. Fish and Wildlife Service (USFWS) Habitat Evaluation Procedures (HEP) were used to determine the number of habitat units credited to BPA for acquired lands. Upland and riparian forest, upland and riparian shrub, and grassland rover types are evaluated in this study. Targeted wildlife species include downy woodpecker (Picoides pubescens), black-capped chickadee (Parus atricopillus), blue grouse (Dendragapus obscurus), great blue heron (Ardea herodias), yellow warbler (Dendroica petechia), mink (Mustela vison), and Western meadowlark (Sturnella neglects). Habitat surveys were conducted in 1998 and 1999 in accordance with published HEP protocols and included 65,300, 594m{sup 2} plots, and 112 one-tenth-acre plots. Between 153.3 and 7,187.46 acres were evaluated for each target wildlife mitigation species. Derived habitat suitability indices were multiplied by corresponding cover-type acreages to determine the number of habitat units for each species. The total baseline habitat units credited to BPA for the Rainwater Wildlife Area and its seven target species is 5,185.3 habitat units. Factors limiting habitat suitability are related to the direct, indirect, and cumulative effects of past livestock grazing, road construction, and timber harvest which have simplified the structure, composition, and diversity of native plant communities. Alternatives for protecting and improving habitat suitability include exclusion of livestock grazing, road de-commissioning/obliteration, reforestation and thinning, control of competing and unwanted vegetation (including noxious weeds), reestablishing displaced or reduced native

  20. STRUCTURAL MODELLING

    Directory of Open Access Journals (Sweden)

    Tea Ya. Danelyan

    2014-01-01

    Full Text Available The article states the general principles of structural modeling in aspect of the theory of systems and gives the interrelation with other types of modeling to adjust them to the main directions of modeling. Mathematical methods of structural modeling, in particular method of expert evaluations are considered.

  1. (HEV) Model

    African Journals Online (AJOL)

    Moatez Billah HARIDA

    The use of the simulator “Hybrid Electrical Vehicle Model Balances Fidelity and. Speed (HEVMBFS)” and the global control strategy make it possible to achieve encouraging results. Key words: Series parallel hybrid vehicle - nonlinear model - linear model - Diesel engine - Engine modelling -. HEV simulator - Predictive ...

  2. Constitutive Models

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Piccolo, Chiara; Heitzig, Martina

    2011-01-01

    This chapter presents various types of constitutive models and their applications. There are 3 aspects dealt with in this chapter, namely: creation and solution of property models, the application of parameter estimation and finally application examples of constitutive models. A systematic...... procedure is introduced for the analysis and solution of property models. Models that capture and represent the temperature dependent behaviour of physical properties are introduced, as well as equation of state models (EOS) such as the SRK EOS. Modelling of liquid phase activity coefficients are also...

  3. Model theory

    CERN Document Server

    Chang, CC

    2012-01-01

    Model theory deals with a branch of mathematical logic showing connections between a formal language and its interpretations or models. This is the first and most successful textbook in logical model theory. Extensively updated and corrected in 1990 to accommodate developments in model theoretic methods - including classification theory and nonstandard analysis - the third edition added entirely new sections, exercises, and references. Each chapter introduces an individual method and discusses specific applications. Basic methods of constructing models include constants, elementary chains, Sko

  4. Black woodpecker Dryocopus martius (L., 1758 distribution, abundance, habitatuse and breeding performance in a recentlycolonized region in SW Europe

    Directory of Open Access Journals (Sweden)

    Olano, M., Aierbe, T., Beñaran, H., Hurtado, R., Ugarte, Urruzola, A., Vázquez, J., Ansorregi, F., Galdos, A. ... [et al.

    2015-01-01

    localidades potenciales utilizando inventarios forestales, y cada localidad fue visitada durante el periodo enero-marzo. Las localidades ocupadas se consideraron “dominios vitales reproductivos” cuando se pudo comprobar el emparejamiento o la nidificación, o cuando se registró presencia de individuos en un mínimo de tres visitas consecutivas. Se vigiló el desarrollo de la reproducción en nidos activos durante mayo y junio. Se detectaron y cartografiaron 21 "dominios vitales reproductivos", distribuidos fundamentalmente a lo largo de las franjas oriental y meridional del área de estudio. Las determinantes ambientales relacionadas positivamente con la presencia de "dominios vitales reproductivos" fueron elevada cobertura arbolada, estructura madura, superficies de haya Fagus sylvatica, bosque mixto caducifolio y pino laricio Pinus nigra, y parcelas forestales poco fragmentadas. Las plantaciones de pino de Monterrey P. radiata y las alturas bajas del arbolado se seleccionaron negativamente. Las parcelas de alimentación preferidas incluyeron proporciones de roble americano Quercus rubra y plantaciones de pino laricio. Se detectaron trece nidos activos. Todos los nidos salvo dos fueron excavados en hayas. El éxito de cría fue elevado (92% pero la tasa de vuelo (1.8 estuvo por debajo de los promedios descritos en Europa, lo que podría indicar limitaciones intrínsecas en esta población periférica.

  5. Shortleaf pine-bluestem restoration for red-cockaded woodpeckers in the Ouachita Mountains: Implications for other taxa

    Science.gov (United States)

    Ronald E. Thill; D. Craig Rudolph; Nancy E. Koerth

    2004-01-01

    The more xeric south- and west-facing slopes of the Ouachita Mountains of west-central Arkansas once supported fire-maintained shortleaf pine (Pinus echinata) forests with a well-developed herbaceous understory. Fire suppression following the original harvest of these forests resulted in forests with increasingly abundant woody vegetation in the...

  6. Managing Loblolly Pine (Pinus taeda) Stands for the Restoration of Red-cockaded Woodpecker (Picoides borealis) Habitat

    Science.gov (United States)

    2014-03-01

    nutrients are often limiting in forest systems and constituted the fertilizer amendment treatment. In gap plots, we tested for effects of gap position on... constitute or imply its endorsement, recommendation, or favoring by the Department of Defense. ii TABLE OF CONTENTS Page LIST OF...Graminoid Perennial 2 Smilax rotundifolia Shrub/vine Perennial 2 LowBA Callicarpa americana Shrub Perennial 2 Clearcut Quercus marilandica Tree

  7. Galactic models

    International Nuclear Information System (INIS)

    Buchler, J.R.; Gottesman, S.T.; Hunter, J.H. Jr.

    1990-01-01

    Various papers on galactic models are presented. Individual topics addressed include: observations relating to galactic mass distributions; the structure of the Galaxy; mass distribution in spiral galaxies; rotation curves of spiral galaxies in clusters; grand design, multiple arm, and flocculent spiral galaxies; observations of barred spirals; ringed galaxies; elliptical galaxies; the modal approach to models of galaxies; self-consistent models of spiral galaxies; dynamical models of spiral galaxies; N-body models. Also discussed are: two-component models of galaxies; simulations of cloudy, gaseous galactic disks; numerical experiments on the stability of hot stellar systems; instabilities of slowly rotating galaxies; spiral structure as a recurrent instability; model gas flows in selected barred spiral galaxies; bar shapes and orbital stochasticity; three-dimensional models; polar ring galaxies; dynamical models of polar rings

  8. Interface models

    DEFF Research Database (Denmark)

    Ravn, Anders P.; Staunstrup, Jørgen

    1994-01-01

    This paper proposes a model for specifying interfaces between concurrently executing modules of a computing system. The model does not prescribe a particular type of communication protocol and is aimed at describing interfaces between both software and hardware modules or a combination of the two....... The model describes both functional and timing properties of an interface...

  9. Hydrological models are mediating models

    Science.gov (United States)

    Babel, L. V.; Karssenberg, D.

    2013-08-01

    Despite the increasing role of models in hydrological research and decision-making processes, only few accounts of the nature and function of models exist in hydrology. Earlier considerations have traditionally been conducted while making a clear distinction between physically-based and conceptual models. A new philosophical account, primarily based on the fields of physics and economics, transcends classes of models and scientific disciplines by considering models as "mediators" between theory and observations. The core of this approach lies in identifying models as (1) being only partially dependent on theory and observations, (2) integrating non-deductive elements in their construction, and (3) carrying the role of instruments of scientific enquiry about both theory and the world. The applicability of this approach to hydrology is evaluated in the present article. Three widely used hydrological models, each showing a different degree of apparent physicality, are confronted to the main characteristics of the "mediating models" concept. We argue that irrespective of their kind, hydrological models depend on both theory and observations, rather than merely on one of these two domains. Their construction is additionally involving a large number of miscellaneous, external ingredients, such as past experiences, model objectives, knowledge and preferences of the modeller, as well as hardware and software resources. We show that hydrological models convey the role of instruments in scientific practice by mediating between theory and the world. It results from these considerations that the traditional distinction between physically-based and conceptual models is necessarily too simplistic and refers at best to the stage at which theory and observations are steering model construction. The large variety of ingredients involved in model construction would deserve closer attention, for being rarely explicitly presented in peer-reviewed literature. We believe that devoting

  10. ICRF modelling

    International Nuclear Information System (INIS)

    Phillips, C.K.

    1985-12-01

    This lecture provides a survey of the methods used to model fast magnetosonic wave coupling, propagation, and absorption in tokamaks. The validity and limitations of three distinct types of modelling codes, which will be contrasted, include discrete models which utilize ray tracing techniques, approximate continuous field models based on a parabolic approximation of the wave equation, and full field models derived using finite difference techniques. Inclusion of mode conversion effects in these models and modification of the minority distribution function will also be discussed. The lecture will conclude with a presentation of time-dependent global transport simulations of ICRF-heated tokamak discharges obtained in conjunction with the ICRF modelling codes. 52 refs., 15 figs

  11. Modelling in Business Model design

    NARCIS (Netherlands)

    Simonse, W.L.

    2013-01-01

    It appears that business model design might not always produce a design or model as the expected result. However when designers are involved, a visual model or artefact is produced. To assist strategic managers in thinking about how they can act, the designers challenge is to combine strategy and

  12. Ventilation Model

    International Nuclear Information System (INIS)

    Yang, H.

    1999-01-01

    The purpose of this analysis and model report (AMR) for the Ventilation Model is to analyze the effects of pre-closure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts and provide heat removal data to support EBS design. It will also provide input data (initial conditions, and time varying boundary conditions) for the EBS post-closure performance assessment and the EBS Water Distribution and Removal Process Model. The objective of the analysis is to develop, describe, and apply calculation methods and models that can be used to predict thermal conditions within emplacement drifts under forced ventilation during the pre-closure period. The scope of this analysis includes: (1) Provide a general description of effects and heat transfer process of emplacement drift ventilation. (2) Develop a modeling approach to simulate the impacts of pre-closure ventilation on the thermal conditions in emplacement drifts. (3) Identify and document inputs to be used for modeling emplacement ventilation. (4) Perform calculations of temperatures and heat removal in the emplacement drift. (5) Address general considerations of the effect of water/moisture removal by ventilation on the repository thermal conditions. The numerical modeling in this document will be limited to heat-only modeling and calculations. Only a preliminary assessment of the heat/moisture ventilation effects and modeling method will be performed in this revision. Modeling of moisture effects on heat removal and emplacement drift temperature may be performed in the future

  13. Turbulence modelling

    International Nuclear Information System (INIS)

    Laurence, D.

    1997-01-01

    This paper is an introduction course in modelling turbulent thermohydraulics, aimed at computational fluid dynamics users. No specific knowledge other than the Navier Stokes equations is required beforehand. Chapter I (which those who are not beginners can skip) provides basic ideas on turbulence physics and is taken up in a textbook prepared by the teaching team of the ENPC (Benque, Viollet). Chapter II describes turbulent viscosity type modelling and the 2k-ε two equations model. It provides details of the channel flow case and the boundary conditions. Chapter III describes the 'standard' (R ij -ε) Reynolds tensions transport model and introduces more recent models called 'feasible'. A second paper deals with heat transfer and the effects of gravity, and returns to the Reynolds stress transport model. (author)

  14. Mathematical modelling

    CERN Document Server

    2016-01-01

    This book provides a thorough introduction to the challenge of applying mathematics in real-world scenarios. Modelling tasks rarely involve well-defined categories, and they often require multidisciplinary input from mathematics, physics, computer sciences, or engineering. In keeping with this spirit of modelling, the book includes a wealth of cross-references between the chapters and frequently points to the real-world context. The book combines classical approaches to modelling with novel areas such as soft computing methods, inverse problems, and model uncertainty. Attention is also paid to the interaction between models, data and the use of mathematical software. The reader will find a broad selection of theoretical tools for practicing industrial mathematics, including the analysis of continuum models, probabilistic and discrete phenomena, and asymptotic and sensitivity analysis.

  15. Modelling Overview

    DEFF Research Database (Denmark)

    Larsen, Lars Bjørn; Vesterager, Johan

    sharing many of the characteristics of a virtual enterprise. This extended enterprise will have the following characteristics: The extended enterprise is focused on satisfying the current customer requirement so that it has a limited life expectancy, but should be capable of being recreated to deal....... One or more units from beyond the network may complement the extended enterprise. The common reference model for this extended enterprise will utilise GERAM (Generalised Enterprise Reference Architecture and Methodology) to provide an architectural framework for the modelling carried out within......This report provides an overview of the existing models of global manufacturing, describes the required modelling views and associated methods and identifies tools, which can provide support for this modelling activity.The model adopted for global manufacturing is that of an extended enterprise...

  16. Mathematical modelling

    DEFF Research Database (Denmark)

    Blomhøj, Morten

    2004-01-01

    modelling, however, can be seen as a practice of teaching that place the relation between real life and mathematics into the centre of teaching and learning mathematics, and this is relevant at all levels. Modelling activities may motivate the learning process and help the learner to establish cognitive......Developing competences for setting up, analysing and criticising mathematical models are normally seen as relevant only from and above upper secondary level. The general belief among teachers is that modelling activities presuppose conceptual understanding of the mathematics involved. Mathematical...... roots for the construction of important mathematical concepts. In addition competences for setting up, analysing and criticising modelling processes and the possible use of models is a formative aim in this own right for mathematics teaching in general education. The paper presents a theoretical...

  17. Event Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2001-01-01

    The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics. We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...... be characterized by their occurrence times and the participating books and borrowers. When we characterize events as information objects we focus on concepts like information structures. When viewed as change agents events are phenomena that trigger change. For example, when borrow event occurs books are moved...

  18. Model : making

    OpenAIRE

    Bottle, Neil

    2013-01-01

    The Model : making exhibition was curated by Brian Kennedy in collaboration with Allies & Morrison in September 2013. For the London Design Festival, the Model : making exhibition looked at the increased use of new technologies by both craft-makers and architectural model makers. In both practices traditional ways of making by hand are increasingly being combined with the latest technologies of digital imaging, laser cutting, CNC machining and 3D printing. This exhibition focussed on ...

  19. Spherical models

    CERN Document Server

    Wenninger, Magnus J

    2012-01-01

    Well-illustrated, practical approach to creating star-faced spherical forms that can serve as basic structures for geodesic domes. Complete instructions for making models from circular bands of paper with just a ruler and compass. Discusses tessellation, or tiling, and how to make spherical models of the semiregular solids and concludes with a discussion of the relationship of polyhedra to geodesic domes and directions for building models of domes. "". . . very pleasant reading."" - Science. 1979 edition.

  20. Modeling Documents with Event Model

    Directory of Open Access Journals (Sweden)

    Longhui Wang

    2015-08-01

    Full Text Available Currently deep learning has made great breakthroughs in visual and speech processing, mainly because it draws lessons from the hierarchical mode that brain deals with images and speech. In the field of NLP, a topic model is one of the important ways for modeling documents. Topic models are built on a generative model that clearly does not match the way humans write. In this paper, we propose Event Model, which is unsupervised and based on the language processing mechanism of neurolinguistics, to model documents. In Event Model, documents are descriptions of concrete or abstract events seen, heard, or sensed by people and words are objects in the events. Event Model has two stages: word learning and dimensionality reduction. Word learning is to learn semantics of words based on deep learning. Dimensionality reduction is the process that representing a document as a low dimensional vector by a linear mode that is completely different from topic models. Event Model achieves state-of-the-art results on document retrieval tasks.

  1. Didactical modelling

    DEFF Research Database (Denmark)

    Højgaard, Tomas; Hansen, Rune

    The purpose of this paper is to introduce Didactical Modelling as a research methodology in mathematics education. We compare the methodology with other approaches and argue that Didactical Modelling has its own specificity. We discuss the methodological “why” and explain why we find it useful...... to construct this approach in mathematics education research....

  2. Virtual modeling

    NARCIS (Netherlands)

    Flores, J.; Kiss, S.; Cano, P.; Nijholt, Antinus; Zwiers, Jakob

    2003-01-01

    We concentrate our efforts on building virtual modelling environments where the content creator uses controls (widgets) as an interactive adjustment modality for the properties of the edited objects. Besides the advantage of being an on-line modelling approach (visualised just like any other on-line

  3. Animal models

    DEFF Research Database (Denmark)

    Gøtze, Jens Peter; Krentz, Andrew

    2014-01-01

    In this issue of Cardiovascular Endocrinology, we are proud to present a broad and dedicated spectrum of reviews on animal models in cardiovascular disease. The reviews cover most aspects of animal models in science from basic differences and similarities between small animals and the human...

  4. Education models

    NARCIS (Netherlands)

    Poortman, Sybilla; Sloep, Peter

    2006-01-01

    Educational models describes a case study on a complex learning object. Possibilities are investigated for using this learning object, which is based on a particular educational model, outside of its original context. Furthermore, this study provides advice that might lead to an increase in

  5. Modeling Sunspots

    Science.gov (United States)

    Oh, Phil Seok; Oh, Sung Jin

    2013-01-01

    Modeling in science has been studied by education researchers for decades and is now being applied broadly in school. It is among the scientific practices featured in the "Next Generation Science Standards" ("NGSS") (Achieve Inc. 2013). This article describes modeling activities in an extracurricular science club in a high…

  6. Battery Modeling

    NARCIS (Netherlands)

    Jongerden, M.R.; Haverkort, Boudewijn R.H.M.

    2008-01-01

    The use of mobile devices is often limited by the capacity of the employed batteries. The battery lifetime determines how long one can use a device. Battery modeling can help to predict, and possibly extend this lifetime. Many different battery models have been developed over the years. However,

  7. VENTILATION MODEL

    International Nuclear Information System (INIS)

    V. Chipman

    2002-01-01

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses

  8. Modelling Constructs

    DEFF Research Database (Denmark)

    Kindler, Ekkart

    2009-01-01

    , these notations have been extended in order to increase expressiveness and to be more competitive. This resulted in an increasing number of notations and formalisms for modelling business processes and in an increase of the different modelling constructs provided by modelling notations, which makes it difficult......There are many different notations and formalisms for modelling business processes and workflows. These notations and formalisms have been introduced with different purposes and objectives. Later, influenced by other notations, comparisons with other tools, or by standardization efforts...... to compare modelling notations and to make transformations between them. One of the reasons is that, in each notation, the new concepts are introduced in a different way by extending the already existing constructs. In this chapter, we go the opposite direction: We show that it is possible to add most...

  9. OSPREY Model

    Energy Technology Data Exchange (ETDEWEB)

    Veronica J. Rutledge

    2013-01-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of off-gas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data is obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data and parameters were input into the adsorption model to develop models specific for krypton adsorption. The same can be done for iodine, xenon, and tritium. The model will be validated with experimental breakthrough curves. Customers will be given access to

  10. Modeling Applications.

    Science.gov (United States)

    McMEEKIN, Thomas A; Ross, Thomas

    1996-12-01

    The concept of predictive microbiology has developed rapidly through the initial phases of experimental design and model development and the subsequent phase of model validation. A fully validated model represents a general rule which may be brought to bear on particular cases. For some microorganism/food combinations, sufficient confidence now exists to indicate substantial benefits to the food industry from use of predictive models. Several types of devices are available to monitor and record environmental conditions (particularly temperature). These "environmental histories" can be interpreted, using predictive models, in terms of microbial proliferation. The current challenge is to provide systems for the collection and interpretation of environmental information which combine ease of use, reliability, and security, providing the industrial user with the ability to make informed and precise decisions regarding the quality and safety of foods. Many specific applications for predictive modeling can be developed from a basis of understanding the inherent qualities of a fully validated model. These include increased precision and confidence in predictions based on accumulation of quantitative data, objective and rapid assessment of the effect of environmental conditions on microbial proliferation, and flexibility in monitoring the relative contribution of component parts of processing, distribution, and storage systems for assurance of shelf life and safety.

  11. A Model for Math Modeling

    Science.gov (United States)

    Lin, Tony; Erfan, Sasan

    2016-01-01

    Mathematical modeling is an open-ended research subject where no definite answers exist for any problem. Math modeling enables thinking outside the box to connect different fields of studies together including statistics, algebra, calculus, matrices, programming and scientific writing. As an integral part of society, it is the foundation for many…

  12. Modeling complexes of modeled proteins.

    Science.gov (United States)

    Anishchenko, Ivan; Kundrotas, Petras J; Vakser, Ilya A

    2017-03-01

    Structural characterization of proteins is essential for understanding life processes at the molecular level. However, only a fraction of known proteins have experimentally determined structures. This fraction is even smaller for protein-protein complexes. Thus, structural modeling of protein-protein interactions (docking) primarily has to rely on modeled structures of the individual proteins, which typically are less accurate than the experimentally determined ones. Such "double" modeling is the Grand Challenge of structural reconstruction of the interactome. Yet it remains so far largely untested in a systematic way. We present a comprehensive validation of template-based and free docking on a set of 165 complexes, where each protein model has six levels of structural accuracy, from 1 to 6 Å C α RMSD. Many template-based docking predictions fall into acceptable quality category, according to the CAPRI criteria, even for highly inaccurate proteins (5-6 Å RMSD), although the number of such models (and, consequently, the docking success rate) drops significantly for models with RMSD > 4 Å. The results show that the existing docking methodologies can be successfully applied to protein models with a broad range of structural accuracy, and the template-based docking is much less sensitive to inaccuracies of protein models than the free docking. Proteins 2017; 85:470-478. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  13. RNICE Model

    DEFF Research Database (Denmark)

    Pedersen, Mogens Jin; Stritch, Justin Michael

    2018-01-01

    contributes knowledge about a social phenomenon and advances knowledge in the public administration and management literatures. The RNICE model provides a vehicle for researchers who seek to evaluate or demonstrate the value of a replication study systematically. We illustrate the practical application...... research. Recently, scholars have issued calls for more replication, but academic reflections on when replication adds substantive value to public administration and management research are needed. This concise article presents a conceptual model, RNICE, for assessing when and how a replication study...... of the model using two previously published replication studies as examples....

  14. Correct Models

    OpenAIRE

    Blacher, René

    2010-01-01

    Ce rapport complete les deux rapports précédents et apporte une explication plus simple aux résultats précédents : à savoir la preuve que les suites obtenues sont aléatoires.; In previous reports, we have show how to transform a text $y_n$ in a random sequence by using functions of Fibonacci $T_q$. Now, in this report, we obtain a clearer result by proving that $T_q(y_n)$ has the IID model as correct model. But, it is necessary to define correctly a correct model. Then, we study also this pro...

  15. Paleoclimate Modeling

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Computer simulations of past climate. Variables provided as model output are described by parameter keyword. In some cases the parameter keywords are a subset of all...

  16. Anchor Modeling

    Science.gov (United States)

    Regardt, Olle; Rönnbäck, Lars; Bergholtz, Maria; Johannesson, Paul; Wohed, Petia

    Maintaining and evolving data warehouses is a complex, error prone, and time consuming activity. The main reason for this state of affairs is that the environment of a data warehouse is in constant change, while the warehouse itself needs to provide a stable and consistent interface to information spanning extended periods of time. In this paper, we propose a modeling technique for data warehousing, called anchor modeling, that offers non-destructive extensibility mechanisms, thereby enabling robust and flexible management of changes in source systems. A key benefit of anchor modeling is that changes in a data warehouse environment only require extensions, not modifications, to the data warehouse. This ensures that existing data warehouse applications will remain unaffected by the evolution of the data warehouse, i.e. existing views and functions will not have to be modified as a result of changes in the warehouse model.

  17. Linear Models

    CERN Document Server

    Searle, Shayle R

    2012-01-01

    This 1971 classic on linear models is once again available--as a Wiley Classics Library Edition. It features material that can be understood by any statistician who understands matrix algebra and basic statistical methods.

  18. Environmental Modeling

    Science.gov (United States)

    EPA's modeling community is working to gain insights into certain parts of a physical, biological, economic, or social system by conducting environmental assessments for Agency decision making to complex environmental issues.

  19. Quark models

    International Nuclear Information System (INIS)

    Rosner, J.L.

    1981-01-01

    This paper invites experimenters to consider the wide variety of tests suggested by the new aspects of quark models since the discovery of charm and beauty, and nonrelativistic models. Colors and flavours are counted and combined into hadrons. The current quark zoo is summarized. Models and theoretical background are studied under: qualitative QCD: strings and bags, potential models, relativistic effects, electromagnetic transitions, gluon emissions, and single quark transition descriptions. Hadrons containing quarks known before 1974 (i.e. that can be made of ''light'' quarks u, d, and s) are treated in Section III, while those containing charmed quarks and beauty (b) quarks are discussed in Section IV. Unfolding the properties of the sixth quark from information on its hadrons is seen as a future application of the methods used in this study

  20. Model theory

    CERN Document Server

    Hodges, Wilfrid

    1993-01-01

    An up-to-date and integrated introduction to model theory, designed to be used for graduate courses (for students who are familiar with first-order logic), and as a reference for more experienced logicians and mathematicians.

  1. Numerical models

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.; Manoj, N.T.

    developed most of the above models. This is a good approximation to simulate horizontal distribution of active and passive variables. The future challenge lies in developing capability to simulate the distribution in the vertical....

  2. Composite models

    International Nuclear Information System (INIS)

    Peccei, R.D.

    If quarks and leptons are composite, it should be possible eventually to calculate their mass spectrum and understand the reasons for the observed family replications, questions which lie beyond the standard model. Alas, all experimental evidence to date points towards quark and lepton elemenarity with the typical momentum scale Λsub(comp), beyond which effects of inner structure may be seen, probably being greater than ITeV. One supersymmetric preon model explained provides a new dynamical alternative for obtaining light fermions which is that these states are quasi Goldstone fermions. This, and similar models are discussed. Although quasi Goldstone fermions provide an answer to the 0sup(th)-order question of composite models the questions of how masses and families are generated remain unanswered. (U.K.)

  3. Ventilation models

    Science.gov (United States)

    Skaaret, Eimund

    Calculation procedures, used in the design of ventilating systems, which are especially suited for displacement ventilation in addition to linking it to mixing ventilation, are addressed. The two zone flow model is considered and the steady state and transient solutions are addressed. Different methods of supplying air are discussed, and different types of air flow are considered: piston flow, plane flow and radial flow. An evaluation model for ventilation systems is presented.

  4. Maturity Models

    DEFF Research Database (Denmark)

    Lasrado, Lester Allan; Vatrapu, Ravi

    2016-01-01

    effects, unicausal reduction, and case specificity. Based on the developments in set theoretical thinking in social sciences and employing methods like Qualitative Comparative Analysis (QCA), Necessary Condition Analysis (NCA), and set visualization techniques, in this position paper, we propose...... and demonstrate a new approach to maturity models in the domain of Information Systems. This position paper describes the set-theoretical approach to maturity models, presents current results and outlines future research work....

  5. Accelerated life models modeling and statistical analysis

    CERN Document Server

    Bagdonavicius, Vilijandas

    2001-01-01

    Failure Time DistributionsIntroductionParametric Classes of Failure Time DistributionsAccelerated Life ModelsIntroductionGeneralized Sedyakin's ModelAccelerated Failure Time ModelProportional Hazards ModelGeneralized Proportional Hazards ModelsGeneralized Additive and Additive-Multiplicative Hazards ModelsChanging Shape and Scale ModelsGeneralizationsModels Including Switch-Up and Cycling EffectsHeredity HypothesisSummaryAccelerated Degradation ModelsIntroductionDegradation ModelsModeling the Influence of Explanatory Varia

  6. Model uncertainty: Probabilities for models?

    International Nuclear Information System (INIS)

    Winkler, R.L.

    1994-01-01

    Like any other type of uncertainty, model uncertainty should be treated in terms of probabilities. The question is how to do this. The most commonly-used approach has a drawback related to the interpretation of the probabilities assigned to the models. If we step back and look at the big picture, asking what the appropriate focus of the model uncertainty question should be in the context of risk and decision analysis, we see that a different probabilistic approach makes more sense, although it raise some implementation questions. Current work that is underway to address these questions looks very promising

  7. Winter Responses of Forest Birds to Habitat Corridors and Gaps

    Directory of Open Access Journals (Sweden)

    Colleen Cassady St. Clair

    1998-12-01

    Full Text Available Forest fragmentation and habitat loss may disrupt the movement or dispersal of forest-dwelling birds. Despite much interest in the severity of these effects and ways of mitigating them, little is known about actual movement patterns in different habitat types. We studied the movement of wintering resident birds, lured by playbacks of mobbing calls, to compare the willingness of forest birds to travel various distances in continuous forest, along narrow corridors (fencerows, and across gaps in forest cover. We also quantified the willingness of Black-capped Chickadees (Poecile atricapillus to cross gaps when alternative forested detour routes were available. All species were less likely to respond to the calls as distance increased to 200 m, although White-breasted Nuthatches (Sitta carolinensis and Hairy Woodpeckers (Picoides villosus were generally less likely to respond than chickadees and Downy Woodpeckers (P. pubescens. Chickadees were as likely to travel in corridors as in continuous forest, but were less likely to cross gaps as the gap distance increased. The other species were less willing to travel in corridors and gaps relative to forest, and the differences among habitats also increased with distance. For chickadees, gap-crossing decisions in the presence of forested detours varied over the range of distances that we tested, and were primarily influenced by detour efficiency (the length of the shortcut relative to the available detour. Over short distances, birds used forested detours, regardless of their efficiency. As absolute distances increased, birds tended to employ larger shortcuts in the open when detour efficiency was low or initial distance in the open was high, but they limited their distance from the nearest forest edge to 25 m. Thus, chickadees were unwilling to cross gaps of > 50 m when they had forested alternatives, yet they sometimes crossed gaps as large as 200 m when no such choice existed. Our results suggest that

  8. Mechanistic models

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, S.B.

    1990-09-01

    Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) ``interaction`` of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.

  9. Mechanistic models

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, S.B.

    1990-09-01

    Several models and theories are reviewed that incorporate the idea of radiation-induced lesions (repairable and/or irreparable) that can be related to molecular lesions in the DNA molecule. Usually the DNA double-strand or chromatin break is suggested as the critical lesion. In the models, the shoulder on the low-LET survival curve is hypothesized as being due to one (or more) of the following three mechanisms: (1) interaction'' of lesions produced by statistically independent particle tracks; (2) nonlinear (i.e., linear-quadratic) increase in the yield of initial lesions, and (3) saturation of repair processes at high dose. Comparisons are made between the various approaches. Several significant advances in model development are discussed; in particular, a description of the matrix formulation of the Markov versions of the RMR and LPL models is given. The more advanced theories have incorporated statistical fluctuations in various aspects of the energy-loss and lesion-formation process. An important direction is the inclusion of physical and chemical processes into the formulations by incorporating relevant track structure theory (Monte Carlo track simulations) and chemical reactions of radiation-induced radicals. At the biological end, identification of repair genes and how they operate as well as a better understanding of how DNA misjoinings lead to lethal chromosome aberrations are needed for appropriate inclusion into the theories. More effort is necessary to model the complex end point of radiation-induced carcinogenesis.

  10. Reflectance Modeling

    Science.gov (United States)

    Smith, J. A.; Cooper, K.; Randolph, M.

    1984-01-01

    A classical description of the one dimensional radiative transfer treatment of vegetation canopies was completed and the results were tested against measured prairie (blue grama) and agricultural canopies (soybean). Phase functions are calculated in terms of directly measurable biophysical characteristics of the canopy medium. While the phase functions tend to exhibit backscattering anisotropy, their exact behavior is somewhat more complex and wavelength dependent. A Monte Carlo model was developed that treats soil surfaces with large periodic variations in three dimensions. A photon-ray tracing technology is used. Currently, the rough soil surface is described by analytic functions and appropriate geometric calculations performed. A bidirectional reflectance distribution function is calculated and, hence, available for other atmospheric or canopy reflectance models as a lower boundary condition. This technique is used together with an adding model to calculate several cases where Lambertian leaves possessing anisotropic leaf angle distributions yield non-Lambertian reflectance; similar behavior is exhibited for simulated soil surfaces.

  11. Mathematical modeling

    CERN Document Server

    Eck, Christof; Knabner, Peter

    2017-01-01

    Mathematical models are the decisive tool to explain and predict phenomena in the natural and engineering sciences. With this book readers will learn to derive mathematical models which help to understand real world phenomena. At the same time a wealth of important examples for the abstract concepts treated in the curriculum of mathematics degrees are given. An essential feature of this book is that mathematical structures are used as an ordering principle and not the fields of application. Methods from linear algebra, analysis and the theory of ordinary and partial differential equations are thoroughly introduced and applied in the modeling process. Examples of applications in the fields electrical networks, chemical reaction dynamics, population dynamics, fluid dynamics, elasticity theory and crystal growth are treated comprehensively.

  12. Modelling language

    CERN Document Server

    Cardey, Sylviane

    2013-01-01

    In response to the need for reliable results from natural language processing, this book presents an original way of decomposing a language(s) in a microscopic manner by means of intra/inter‑language norms and divergences, going progressively from languages as systems to the linguistic, mathematical and computational models, which being based on a constructive approach are inherently traceable. Languages are described with their elements aggregating or repelling each other to form viable interrelated micro‑systems. The abstract model, which contrary to the current state of the art works in int

  13. Molecular modeling

    Directory of Open Access Journals (Sweden)

    Aarti Sharma

    2009-01-01

    Full Text Available The use of computational chemistry in the development of novel pharmaceuticals is becoming an increasingly important tool. In the past, drugs were simply screened for effectiveness. The recent advances in computing power and the exponential growth of the knowledge of protein structures have made it possible for organic compounds to be tailored to decrease the harmful side effects and increase the potency. This article provides a detailed description of the techniques employed in molecular modeling. Molecular modeling is a rapidly developing discipline, and has been supported by the dramatic improvements in computer hardware and software in recent years.

  14. Supernova models

    International Nuclear Information System (INIS)

    Woosley, S.E.; Weaver, T.A.

    1980-01-01

    Recent progress in understanding the observed properties of Type I supernovae as a consequence of the thermonuclear detonation of white dwarf stars and the ensuing decay of the 56 Ni produced therein is reviewed. Within the context of this model for Type I explosions and the 1978 model for Type II explosions, the expected nucleosynthesis and gamma-line spectra from both kinds of supernovae are presented. Finally, a qualitatively new approach to the problem of massive star death and Type II supernovae based upon a combination of rotation and thermonuclear burning is discussed

  15. Cadastral Modeling

    DEFF Research Database (Denmark)

    Stubkjær, Erik

    2005-01-01

    to the modeling of an industrial sector, as it aims at rendering the basic concepts that relate to the domain of real estate and the pertinent human activities. The palpable objects are pieces of land and buildings, documents, data stores and archives, as well as persons in their diverse roles as owners, holders...... to land. The paper advances the position that cadastral modeling has to include not only the physical objects, agents, and information sets of the domain, but also the objectives or requirements of cadastral systems....

  16. (SSE) model

    African Journals Online (AJOL)

    Simple analytic polynomials have been proposed for estimating solar radiation in the traditional Northern, Central and Southern regions of Malawi. There is a strong agreement between the polynomials and the SSE model with R2 values of 0.988, 0.989 and 0.989 and root mean square errors of 0.061, 0.057 and 0.062 ...

  17. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...

  18. Markov model

    Indian Academy of Sciences (India)

    pattern of the watershed LULC, leading to an accretive linear growth of agricultural and settlement areas. The annual rate of ... thereby advocates for better agricultural practices with additional energy subsidy to arrest further forest loss and LULC ...... automaton model and GIS: Long-term urban growth pre- diction for San ...

  19. Cheating models

    DEFF Research Database (Denmark)

    Arnoldi, Jakob

    The article discusses the use of algorithmic models for so-called High Frequency Trading (HFT) in finance. HFT is controversial yet widespread in modern financial markets. It is a form of automated trading technology which critics among other things claim can lead to market manipulation. Drawing ...

  20. Entrepreneurship Models.

    Science.gov (United States)

    Finger Lakes Regional Education Center for Economic Development, Mount Morris, NY.

    This guide describes seven model programs that were developed by the Finger Lakes Regional Center for Economic Development (New York) to meet the training needs of female and minority entrepreneurs to help their businesses survive and grow and to assist disabled and dislocated workers and youth in beginning small businesses. The first three models…

  1. The Model

    DEFF Research Database (Denmark)

    About the reconstruction of Palle Nielsen's (f. 1942) work The Model from 1968: a gigantic playground for children in the museum, where they can freely romp about, climb in ropes, crawl on wooden structures, work with tools, jump in foam rubber, paint with finger paints and dress up in costumes....

  2. Model Checking

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 7. Model Checking - Automated Verification of Computational Systems. Madhavan Mukund. General Article Volume 14 Issue 7 July 2009 pp 667-681. Fulltext. Click here to view fulltext PDF. Permanent link:

  3. Successful modeling?

    Science.gov (United States)

    Lomnitz, Cinna

    Tichelaar and Ruff [1989] propose to “estimate model variance in complicated geophysical problems,” including the determination of focal depth in earthquakes, by means of unconventional statistical methods such as bootstrapping. They are successful insofar as they are able to duplicate the results from more conventional procedures.

  4. Molecular Modeling

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 5. Molecular Modeling: A Powerful Tool for Drug Design and Molecular Docking. Rama Rao Nadendla. General Article Volume 9 Issue 5 May 2004 pp 51-60. Fulltext. Click here to view fulltext PDF. Permanent link:

  5. Turbulence Model

    DEFF Research Database (Denmark)

    Nielsen, Mogens Peter; Shui, Wan; Johansson, Jens

    2011-01-01

    term with stresses depending linearly on the strain rates. This term takes into account the transfer of linear momentum from one part of the fluid to another. Besides there is another term, which takes into account the transfer of angular momentum. Thus the model implies a new definition of turbulence...

  6. Model-reduced inverse modeling

    NARCIS (Netherlands)

    Vermeulen, P.T.M.

    2006-01-01

    Although faster computers have been developed in recent years, they tend to be used to solve even more detailed problems. In many cases this will yield enormous models that can not be solved within acceptable time constraints. Therefore, there is a need for alternative methods that simulate such

  7. Building Models and Building Modelling

    DEFF Research Database (Denmark)

    Jørgensen, Kaj; Skauge, Jørn

    2008-01-01

    I rapportens indledende kapitel beskrives de primære begreber vedrørende bygningsmodeller og nogle fundamentale forhold vedrørende computerbaseret modulering bliver opstillet. Desuden bliver forskellen mellem tegneprogrammer og bygnings­model­lerings­programmer beskrevet. Vigtige aspekter om comp...

  8. Molecular Modelling

    Directory of Open Access Journals (Sweden)

    Aarti Sharma

    2009-12-01

    Full Text Available

    The use of computational chemistry in the development of novel pharmaceuticals is becoming an increasingly important
    tool. In the past, drugs were simply screened for effectiveness. The recent advances in computing power and
    the exponential growth of the knowledge of protein structures have made it possible for organic compounds to tailored to
    decrease harmful side effects and increase the potency. This article provides a detailed description of the techniques
    employed in molecular modeling. Molecular modelling is a rapidly developing discipline, and has been supported from
    the dramatic improvements in computer hardware and software in recent years.

  9. Acyclic models

    CERN Document Server

    Barr, Michael

    2002-01-01

    Acyclic models is a method heavily used to analyze and compare various homology and cohomology theories appearing in topology and algebra. This book is the first attempt to put together in a concise form this important technique and to include all the necessary background. It presents a brief introduction to category theory and homological algebra. The author then gives the background of the theory of differential modules and chain complexes over an abelian category to state the main acyclic models theorem, generalizing and systemizing the earlier material. This is then applied to various cohomology theories in algebra and topology. The volume could be used as a text for a course that combines homological algebra and algebraic topology. Required background includes a standard course in abstract algebra and some knowledge of topology. The volume contains many exercises. It is also suitable as a reference work for researchers.

  10. RNICE Model

    DEFF Research Database (Denmark)

    Pedersen, Mogens Jin; Stritch, Justin Michael

    2018-01-01

    Replication studies relate to the scientific principle of replicability and serve the significant purpose of providing supporting (or contradicting) evidence regarding the existence of a phenomenon. However, replication has never been an integral part of public administration and management...... research. Recently, scholars have issued calls for more replication, but academic reflections on when replication adds substantive value to public administration and management research are needed. This concise article presents a conceptual model, RNICE, for assessing when and how a replication study...... contributes knowledge about a social phenomenon and advances knowledge in the public administration and management literatures. The RNICE model provides a vehicle for researchers who seek to evaluate or demonstrate the value of a replication study systematically. We illustrate the practical application...

  11. Persistent Modelling

    DEFF Research Database (Denmark)

    2012-01-01

    on this subject, this book makes essential reading for anyone considering new ways of thinking about architecture. In drawing upon both historical and contemporary perspectives this book provides evidence of the ways in which relations between representation and the represented continue to be reconsidered......The relationship between representation and the represented is examined here through the notion of persistent modelling. This notion is not novel to the activity of architectural design if it is considered as describing a continued active and iterative engagement with design concerns – an evident...... characteristic of architectural practice. But the persistence in persistent modelling can also be understood to apply in other ways, reflecting and anticipating extended roles for representation. This book identifies three principle areas in which these extensions are becoming apparent within contemporary...

  12. Persistent Modelling

    DEFF Research Database (Denmark)

    on this subject, this book makes essential reading for anyone considering new ways of thinking about architecture. In drawing upon both historical and contemporary perspectives this book provides evidence of the ways in which relations between representation and the represented continue to be reconsidered......The relationship between representation and the represented is examined here through the notion of persistent modelling. This notion is not novel to the activity of architectural design if it is considered as describing a continued active and iterative engagement with design concerns – an evident...... characteristic of architectural practice. But the persistence in persistent modelling can also be understood to apply in other ways, reflecting and anticipating extended roles for representation. This book identifies three principle areas in which these extensions are becoming apparent within contemporary...

  13. Modeling Minds

    DEFF Research Database (Denmark)

    Michael, John

    others' minds. Then (2), in order to bring to light some possible justifications, as well as hazards and criticisms of the methodology of looking time tests, I will take a closer look at the concept of folk psychology and will focus on the idea that folk psychology involves using oneself as a model...... of other people in order to predict and understand their behavior. Finally (3), I will discuss the historical location and significance of the emergence of looking time tests...

  14. Hydroballistics Modeling

    Science.gov (United States)

    1975-01-01

    detailed rendered visible in his photographs by streams of photographs of spheres entering the water small bubbles from electrolysis . So far as is...of the cavity is opaque or, brined wihile the sphere wats still in the oil. At if translucent, the contrast between thle jet and about the time the...and brass, for example) should be so model velocity scale according to Equation 1.18, selected that electrolysis is not a problem. the addition of

  15. Biomimetic modelling.

    OpenAIRE

    Vincent, Julian F V

    2003-01-01

    Biomimetics is seen as a path from biology to engineering. The only path from engineering to biology in current use is the application of engineering concepts and models to biological systems. However, there is another pathway: the verification of biological mechanisms by manufacture, leading to an iterative process between biology and engineering in which the new understanding that the engineering implementation of a biological system can bring is fed back into biology, allowing a more compl...

  16. Modelling Behaviour

    DEFF Research Database (Denmark)

    This book reflects and expands on the current trend in the building industry to understand, simulate and ultimately design buildings by taking into consideration the interlinked elements and forces that act on them. This approach overcomes the traditional, exclusive focus on building tasks, while....... The chapter authors were invited speakers at the 5th Symposium "Modelling Behaviour", which took place at the CITA in Copenhagen in September 2015....

  17. Combustor Modelling

    Science.gov (United States)

    1980-02-01

    a teuto 014aceo 0-oiuato 4 ajj 210- I 14 *Experiments l~~lamCID - l2 C15 model+ Aida ditane &Gray medium K .2 a Experiments hont target n-IO a0 deawa...possibilita di valutazione dello scambio termico in focolai di caldaie per ricaldamento"I Atti E Rassegna Tecnica Societa ingegneri e arc~hitetti in Torino

  18. Persistent Modelling

    DEFF Research Database (Denmark)

    practice: the duration of active influence that representation can hold in relation to the represented; the means, methods and media through which representations are constructed and used; and what it is that is being represented. Featuring contributions from some of the world’s most advanced thinkers....... It also provides critical insight into the use of contemporary modelling tools and methods, together with an examination of the implications their use has within the territories of architectural design, realisation and experience....

  19. Ozone modeling

    International Nuclear Information System (INIS)

    McIllvaine, C.M.

    1994-01-01

    Exhaust gases from power plants that burn fossil fuels contain concentrations of sulfur dioxide (SO 2 ), nitric oxide (NO), particulate matter, hydrocarbon compounds and trace metals. Estimated emissions from the operation of a hypothetical 500 MW coal-fired power plant are given. Ozone is considered a secondary pollutant, since it is not emitted directly into the atmosphere but is formed from other air pollutants, specifically, nitrogen oxides (NO), and non-methane organic compounds (NMOQ) in the presence of sunlight. (NMOC are sometimes referred to as hydrocarbons, HC, or volatile organic compounds, VOC, and they may or may not include methane). Additionally, ozone formation Alternative is a function of the ratio of NMOC concentrations to NO x concentrations. A typical ozone isopleth is shown, generated with the Empirical Kinetic Modeling Approach (EKMA) option of the Environmental Protection Agency's (EPA) Ozone Isopleth Plotting Mechanism (OZIPM-4) model. Ozone isopleth diagrams, originally generated with smog chamber data, are more commonly generated with photochemical reaction mechanisms and tested against smog chamber data. The shape of the isopleth curves is a function of the region (i.e. background conditions) where ozone concentrations are simulated. The location of an ozone concentration on the isopleth diagram is defined by the ratio of NMOC and NO x coordinates of the point, known as the NMOC/NO x ratio. Results obtained by the described model are presented

  20. Modeling biomembranes.

    Energy Technology Data Exchange (ETDEWEB)

    Plimpton, Steven James; Heffernan, Julieanne; Sasaki, Darryl Yoshio; Frischknecht, Amalie Lucile; Stevens, Mark Jackson; Frink, Laura J. Douglas

    2005-11-01

    Understanding the properties and behavior of biomembranes is fundamental to many biological processes and technologies. Microdomains in biomembranes or ''lipid rafts'' are now known to be an integral part of cell signaling, vesicle formation, fusion processes, protein trafficking, and viral and toxin infection processes. Understanding how microdomains form, how they depend on membrane constituents, and how they act not only has biological implications, but also will impact Sandia's effort in development of membranes that structurally adapt to their environment in a controlled manner. To provide such understanding, we created physically-based models of biomembranes. Molecular dynamics (MD) simulations and classical density functional theory (DFT) calculations using these models were applied to phenomena such as microdomain formation, membrane fusion, pattern formation, and protein insertion. Because lipid dynamics and self-organization in membranes occur on length and time scales beyond atomistic MD, we used coarse-grained models of double tail lipid molecules that spontaneously self-assemble into bilayers. DFT provided equilibrium information on membrane structure. Experimental work was performed to further help elucidate the fundamental membrane organization principles.

  1. Weed-Suppressive Soil Bacteria to Reduce Cheatgrass and Improve Vegetation Diversity on ITD Rights-of-Way

    Science.gov (United States)

    2017-06-01

    Transportation departments are challenged by the invasion of downy brome (cheatgrass) and medusahead. The reduction of downy brome (cheat grass) by Weed Suppressive Bacteria (WSB) Pseudomonas fluorescens strain ACK55 was evaluated on roadsides of I-8...

  2. Object Modeling and Building Information Modeling

    OpenAIRE

    Auråen, Hege; Gjemdal, Hanne

    2016-01-01

    The main part of this thesis is an online course (Small Private Online Course) entitled "Introduction to Object Modeling and Building Information Modeling". This supplementary report clarifies the choices made in the process of developing the course. The course examines the basic concepts of object modeling, modeling techniques and a modeling language ​​(UML). Further, building information modeling (BIM) is presented as a modeling process, and the object modeling concepts in the BIM softw...

  3. DTN Modeling in OPNET Modeler

    Directory of Open Access Journals (Sweden)

    PAPAJ Jan

    2014-05-01

    Full Text Available Traditional wireless networks use the concept of the point-to-point forwarding inherited from reliable wired networks which seems to be not ideal for wireless environment. New emerging applications and networks operate mostly disconnected. So-called Delay-Tolerant networks (DTNs are receiving increasing attentions from both academia and industry. DTNs introduced a store-carry-and-forward concept solving the problem of intermittent connectivity. Behavior of such networks is verified by real models, computer simulation or combination of the both approaches. Computer simulation has become the primary and cost effective tool for evaluating the performance of the DTNs. OPNET modeler is our target simulation tool and we wanted to spread OPNET’s simulation opportunity towards DTN. We implemented bundle protocol to OPNET modeler allowing simulate cases based on bundle concept as epidemic forwarding which relies on flooding the network with messages and the forwarding algorithm based on the history of past encounters (PRoPHET. The implementation details will be provided in article.

  4. Model integration and a theory of models

    OpenAIRE

    Dolk, Daniel R.; Kottemann, Jeffrey E.

    1993-01-01

    Model integration extends the scope of model management to include the dimension of manipulation as well. This invariably leads to comparisons with database theory. Model integration is viewed from four perspectives: Organizational, definitional, procedural, and implementational. Strategic modeling is discussed as the organizational motivation for model integration. Schema and process integration are examined as the logical and manipulation counterparts of model integr...

  5. Model Checking Algorithms for Markov Reward Models

    NARCIS (Netherlands)

    Cloth, Lucia; Cloth, L.

    2006-01-01

    Model checking Markov reward models unites two different approaches of model-based system validation. On the one hand, Markov reward models have a long tradition in model-based performance and dependability evaluation. On the other hand, a formal method like model checking allows for the precise

  6. Modelling Defiguration

    DEFF Research Database (Denmark)

    Bork Petersen, Franziska

    2013-01-01

    focus centres on how the catwalk scenography evokes a ‘defiguration’ of the walking models and to what effect. Vibskov’s mobile catwalk draws attention to the walk, which is a key element of models’ performance but which usually functions in fashion shows merely to present clothes in the most...... catwalks. Vibskov’s catwalk induces what the dance scholar Gabriele Brandstetter has labelled a ‘defigurative choregoraphy’: a straying from definitions, which exist in ballet as in other movement-based genres, of how a figure should move and appear (1998). The catwalk scenography in this instance...

  7. Students' Models of Curve Fitting: A Models and Modeling Perspective

    Science.gov (United States)

    Gupta, Shweta

    2010-01-01

    The Models and Modeling Perspectives (MMP) has evolved out of research that began 26 years ago. MMP researchers use Model Eliciting Activities (MEAs) to elicit students' mental models. In this study MMP was used as the conceptual framework to investigate the nature of students' models of curve fitting in a problem-solving environment consisting of…

  8. Growth response of downy birch (Betula pubescens) to moisture treatment at an cut-over peat bog in the Šumava Mts., Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Lanta, Vojtěch; Hazuková, I.

    2005-01-01

    Roč. 42, - (2005), s. 247-256 ISSN 0003-3847 R&D Projects: GA ČR GD206/03/H034 Institutional research plan: CEZ:AV0Z6005908 Keywords : Betula pubescens * cut-over peatland * increment Subject RIV: EF - Botanics Impact factor: 0.315, year: 2005

  9. ALEPH model

    CERN Multimedia

    1989-01-01

    A wooden model of the ALEPH experiment and its cavern. ALEPH was one of 4 experiments at CERN's 27km Large Electron Positron collider (LEP) that ran from 1989 to 2000. During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the Large Hadron Collider in the same tunnel. The cavern and detector are in separate locations - the cavern is stored at CERN and the detector is temporarily on display in Glasgow physics department. Both are available for loan.

  10. The IMACLIM model; Le modele IMACLIM

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This document provides annexes to the IMACLIM model which propose an actualized description of IMACLIM, model allowing the design of an evaluation tool of the greenhouse gases reduction policies. The model is described in a version coupled with the POLES, technical and economical model of the energy industry. Notations, equations, sources, processing and specifications are proposed and detailed. (A.L.B.)

  11. Building Mental Models by Dissecting Physical Models

    Science.gov (United States)

    Srivastava, Anveshna

    2016-01-01

    When students build physical models from prefabricated components to learn about model systems, there is an implicit trade-off between the physical degrees of freedom in building the model and the intensity of instructor supervision needed. Models that are too flexible, permitting multiple possible constructions require greater supervision to…

  12. Atmospheric Models/Global Atmospheric Modeling

    Science.gov (United States)

    1998-09-30

    Atmospheric Models /Global Atmospheric Modeling Timothy F. Hogan Naval Research Laboratory Monterey, CA 93943-5502 phone: (831) 656-4705 fax: (831...to 00-00-1998 4. TITLE AND SUBTITLE Atmospheric Models /Global Atmospheric Modeling 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...initialization of increments, improved cloud prediction, and improved surface fluxes) have been transition to 6.4 (Global Atmospheric Models , PE 0603207N, X-0513

  13. Models in architectural design

    OpenAIRE

    Pauwels, Pieter

    2017-01-01

    Whereas architects and construction specialists used to rely mainly on sketches and physical models as representations of their own cognitive design models, they rely now more and more on computer models. Parametric models, generative models, as-built models, building information models (BIM), and so forth, they are used daily by any practitioner in architectural design and construction. Although processes of abstraction and the actual architectural model-based reasoning itself of course rema...

  14. Rotating universe models

    International Nuclear Information System (INIS)

    Tozini, A.V.

    1984-01-01

    A review is made of some properties of the rotating Universe models. Godel's model is identified as a generalized filted model. Some properties of new solutions of the Einstein's equations, which are rotating non-stationary Universe models, are presented and analyzed. These models have the Godel's model as a particular case. Non-stationary cosmological models are found which are a generalization of the Godel's metrics in an analogous way in which Friedmann is to the Einstein's model. (L.C.) [pt

  15. Wake Expansion Models

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    Different models of wake expansion are presented in this chapter: the 1D momentum theory model, the cylinder analog model and Theodorsen’s model. Far wake models such as the ones from Frandsen or Rathmann or only briefly mentioned. The different models are compared to each other. Results from...

  16. Model Manipulation for End-User Modelers

    DEFF Research Database (Denmark)

    Acretoaie, Vlad

    End-user modelers are domain experts who create and use models as part of their work. They are typically not Software Engineers, and have little or no programming and meta-modeling experience. However, using model manipulation languages developed in the context of Model-Driven Engineering often...... of these proposals. To achieve its first goal, the thesis presents the findings of a Systematic Mapping Study showing that human factors topics are scarcely and relatively poorly addressed in model transformation research. Motivated by these findings, the thesis explores the requirements of end-user modelers......, and transformations using their modeling notation and editor of choice. The VM* languages are implemented via a single execution engine, the VM* Runtime, built on top of the Henshin graph-based transformation engine. This approach combines the benefits of flexibility, maturity, and formality. To simplify model editor...

  17. Model-to-model interface for multiscale materials modeling

    Energy Technology Data Exchange (ETDEWEB)

    Antonelli, Perry Edward [Iowa State Univ., Ames, IA (United States)

    2017-12-17

    A low-level model-to-model interface is presented that will enable independent models to be linked into an integrated system of models. The interface is based on a standard set of functions that contain appropriate export and import schemas that enable models to be linked with no changes to the models themselves. These ideas are presented in the context of a specific multiscale material problem that couples atomistic-based molecular dynamics calculations to continuum calculations of fluid ow. These simulations will be used to examine the influence of interactions of the fluid with an adjacent solid on the fluid ow. The interface will also be examined by adding it to an already existing modeling code, Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) and comparing it with our own molecular dynamics code.

  18. Concept Modeling vs. Data modeling in Practice

    DEFF Research Database (Denmark)

    Madsen, Bodil Nistrup; Erdman Thomsen, Hanne

    2015-01-01

    This chapter shows the usefulness of terminological concept modeling as a first step in data modeling. First, we introduce terminological concept modeling with terminological ontologies, i.e. concept systems enriched with characteristics modeled as feature specifications. This enables a formal...... account of the inheritance of characteristics and allows us to introduce a number of principles and constraints which render concept modeling more coherent than earlier approaches. Second, we explain how terminological ontologies can be used as the basis for developing conceptual and logical data models...

  19. Cognitive models embedded in system simulation models

    International Nuclear Information System (INIS)

    Siegel, A.I.; Wolf, J.J.

    1982-01-01

    If we are to discuss and consider cognitive models, we must first come to grips with two questions: (1) What is cognition; (2) What is a model. Presumably, the answers to these questions can provide a basis for defining a cognitive model. Accordingly, this paper first places these two questions into perspective. Then, cognitive models are set within the context of computer simulation models and a number of computer simulations of cognitive processes are described. Finally, pervasive issues are discussed vis-a-vis cognitive modeling in the computer simulation context

  20. Business Model Innovation

    OpenAIRE

    Dodgson, Mark; Gann, David; Phillips, Nelson; Massa, Lorenzo; Tucci, Christopher

    2014-01-01

    The chapter offers a broad review of the literature at the nexus between Business Models and innovation studies, and examines the notion of Business Model Innovation in three different situations: Business Model Design in newly formed organizations, Business Model Reconfiguration in incumbent firms, and Business Model Innovation in the broad context of sustainability. Tools and perspectives to make sense of Business Models and support managers and entrepreneurs in dealing with Business Model ...

  1. Air Quality Dispersion Modeling - Alternative Models

    Science.gov (United States)

    Models, not listed in Appendix W, that can be used in regulatory applications with case-by-case justification to the Reviewing Authority as noted in Section 3.2, Use of Alternative Models, in Appendix W.

  2. Wake modelling combining mesoscale and microscale models

    DEFF Research Database (Denmark)

    Badger, Jake; Volker, Patrick; Prospathospoulos, J.

    2013-01-01

    parameterizations are demonstrated in theWeather Research and Forecasting mesoscale model (WRF) in an idealized atmospheric flow. The model framework is the Horns Rev I wind farm experiencing an 7.97 m/s wind from 269.4o. Three of the four parameterizations use thrust output from the CRESflow-NS microscale model......In this paper the basis for introducing thrust information from microscale wake models into mesocale model wake parameterizations will be described. A classification system for the different types of mesoscale wake parameterizations is suggested and outlined. Four different mesoscale wake....... The characteristics of the mesoscale wake that developed from the four parameterizations are examined. In addition the mesoscale model wakes are compared to measurement data from Horns Rev I. Overall it is seen as an advantage to incorporate microscale model data in mesocale model wake parameterizations....

  3. A Model of Trusted Measurement Model

    OpenAIRE

    Ma Zhili; Wang Zhihao; Dai Liang; Zhu Xiaoqin

    2017-01-01

    A model of Trusted Measurement supporting behavior measurement based on trusted connection architecture (TCA) with three entities and three levels is proposed, and a frame to illustrate the model is given. The model synthesizes three trusted measurement dimensions including trusted identity, trusted status and trusted behavior, satisfies the essential requirements of trusted measurement, and unified the TCA with three entities and three levels.

  4. Molecular Models: Construction of Models with Magnets

    Directory of Open Access Journals (Sweden)

    Kalinovčić P.

    2015-07-01

    Full Text Available Molecular models are indispensable tools in teaching chemistry. Beside their high price, commercially available models are generally too small for classroom demonstration. This paper suggests how to make space-filling (callote models from Styrofoam with magnetic balls as connectors and disc magnets for showing molecular polarity

  5. Target Scattering Metrics: Model-Model and Model Data comparisons

    Science.gov (United States)

    2017-12-13

    be suitable for input to classification schemes. The investigated metrics are then applied to model-data comparisons. INTRODUCTION Metrics for...stainless steel replica of artillery shell Table 7. Targets used in the TIER simulations for the metrics study. C. Four Potential Metrics: Four...Four metrics were investigated. The metric, based on 2D cross-correlation, is typically used in classification algorithms. Model-model comparisons

  6. Modelling binary data

    CERN Document Server

    Collett, David

    2002-01-01

    INTRODUCTION Some Examples The Scope of this Book Use of Statistical Software STATISTICAL INFERENCE FOR BINARY DATA The Binomial Distribution Inference about the Success Probability Comparison of Two Proportions Comparison of Two or More Proportions MODELS FOR BINARY AND BINOMIAL DATA Statistical Modelling Linear Models Methods of Estimation Fitting Linear Models to Binomial Data Models for Binomial Response Data The Linear Logistic Model Fitting the Linear Logistic Model to Binomial Data Goodness of Fit of a Linear Logistic Model Comparing Linear Logistic Models Linear Trend in Proportions Comparing Stimulus-Response Relationships Non-Convergence and Overfitting Some other Goodness of Fit Statistics Strategy for Model Selection Predicting a Binary Response Probability BIOASSAY AND SOME OTHER APPLICATIONS The Tolerance Distribution Estimating an Effective Dose Relative Potency Natural Response Non-Linear Logistic Regression Models Applications of the Complementary Log-Log Model MODEL CHECKING Definition of Re...

  7. Modelling of Hydraulic Robot

    DEFF Research Database (Denmark)

    Madsen, Henrik; Zhou, Jianjun; Hansen, Lars Henrik

    1997-01-01

    This paper describes a case study of identifying the physical model (or the grey box model) of a hydraulic test robot. The obtained model is intended to provide a basis for model-based control of the robot. The physical model is formulated in continuous time and is derived by application...

  8. Automated data model evaluation

    International Nuclear Information System (INIS)

    Kazi, Zoltan; Kazi, Ljubica; Radulovic, Biljana

    2012-01-01

    Modeling process is essential phase within information systems development and implementation. This paper presents methods and techniques for analysis and evaluation of data model correctness. Recent methodologies and development results regarding automation of the process of model correctness analysis and relations with ontology tools has been presented. Key words: Database modeling, Data model correctness, Evaluation

  9. Elastic Appearance Models

    DEFF Research Database (Denmark)

    Hansen, Mads Fogtmann; Fagertun, Jens; Larsen, Rasmus

    2011-01-01

    This paper presents a fusion of the active appearance model (AAM) and the Riemannian elasticity framework which yields a non-linear shape model and a linear texture model – the active elastic appearance model (EAM). The non-linear elasticity shape model is more flexible than the usual linear subs...

  10. Forest-fire models

    Science.gov (United States)

    Haiganoush Preisler; Alan Ager

    2013-01-01

    For applied mathematicians forest fire models refer mainly to a non-linear dynamic system often used to simulate spread of fire. For forest managers forest fire models may pertain to any of the three phases of fire management: prefire planning (fire risk models), fire suppression (fire behavior models), and postfire evaluation (fire effects and economic models). In...

  11. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  12. From Numeric Models to Granular System Modeling

    Directory of Open Access Journals (Sweden)

    Witold Pedrycz

    2015-03-01

    To make this study self-contained, we briefly recall the key concepts of granular computing and demonstrate how this conceptual framework and its algorithmic fundamentals give rise to granular models. We discuss several representative formal setups used in describing and processing information granules including fuzzy sets, rough sets, and interval calculus. Key architectures of models dwell upon relationships among information granules. We demonstrate how information granularity and its optimization can be regarded as an important design asset to be exploited in system modeling and giving rise to granular models. With this regard, an important category of rule-based models along with their granular enrichments is studied in detail.

  13. Geologic Framework Model Analysis Model Report

    International Nuclear Information System (INIS)

    Clayton, R.

    2000-01-01

    The purpose of this report is to document the Geologic Framework Model (GFM), Version 3.1 (GFM3.1) with regard to data input, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, qualification status of the model, and the differences between Version 3.1 and previous versions. The GFM represents a three-dimensional interpretation of the stratigraphy and structural features of the location of the potential Yucca Mountain radioactive waste repository. The GFM encompasses an area of 65 square miles (170 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the GFM were chosen to encompass the most widely distributed set of exploratory boreholes (the Water Table or WT series) and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. The GFM was constructed from geologic map and borehole data. Additional information from measured stratigraphy sections, gravity profiles, and seismic profiles was also considered. This interim change notice (ICN) was prepared in accordance with the Technical Work Plan for the Integrated Site Model Process Model Report Revision 01 (CRWMS M and O 2000). The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and

  14. Geologic Framework Model Analysis Model Report

    Energy Technology Data Exchange (ETDEWEB)

    R. Clayton

    2000-12-19

    The purpose of this report is to document the Geologic Framework Model (GFM), Version 3.1 (GFM3.1) with regard to data input, modeling methods, assumptions, uncertainties, limitations, and validation of the model results, qualification status of the model, and the differences between Version 3.1 and previous versions. The GFM represents a three-dimensional interpretation of the stratigraphy and structural features of the location of the potential Yucca Mountain radioactive waste repository. The GFM encompasses an area of 65 square miles (170 square kilometers) and a volume of 185 cubic miles (771 cubic kilometers). The boundaries of the GFM were chosen to encompass the most widely distributed set of exploratory boreholes (the Water Table or WT series) and to provide a geologic framework over the area of interest for hydrologic flow and radionuclide transport modeling through the unsaturated zone (UZ). The depth of the model is constrained by the inferred depth of the Tertiary-Paleozoic unconformity. The GFM was constructed from geologic map and borehole data. Additional information from measured stratigraphy sections, gravity profiles, and seismic profiles was also considered. This interim change notice (ICN) was prepared in accordance with the Technical Work Plan for the Integrated Site Model Process Model Report Revision 01 (CRWMS M&O 2000). The constraints, caveats, and limitations associated with this model are discussed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and the

  15. Mathematical Modeling Using MATLAB

    National Research Council Canada - National Science Library

    Phillips, Donovan

    1998-01-01

    .... Mathematical Modeling Using MA MATLAB acts as a companion resource to A First Course in Mathematical Modeling with the goal of guiding the reader to a fuller understanding of the modeling process...

  16. Energy modelling software

    CSIR Research Space (South Africa)

    Osburn, L

    2010-01-01

    Full Text Available The construction industry has turned to energy modelling in order to assist them in reducing the amount of energy consumed by buildings. However, while the energy loads of buildings can be accurately modelled, energy models often under...

  17. Multivariate GARCH models

    DEFF Research Database (Denmark)

    Silvennoinen, Annastiina; Teräsvirta, Timo

    This article contains a review of multivariate GARCH models. Most common GARCH models are presented and their properties considered. This also includes nonparametric and semiparametric models. Existing specification and misspecification tests are discussed. Finally, there is an empirical example...

  18. N-Gram models

    NARCIS (Netherlands)

    Hiemstra, Djoerd; Liu, Ling; Tamer Özsu, M.

    2017-01-01

    In language modeling, n-gram models are probabilistic models of text that use some limited amount of history, or word dependencies, where n refers to the number of words that participate in the dependence relation.

  19. Business Model Canvas

    OpenAIRE

    Souza, D', Austin

    2013-01-01

    Presentatie gegeven op 13 mei 2013 op de bijeenkomst "Business Model Canvas Challenge Assen". Het Business Model Canvas is ontworpen door Alex Osterwalder. Het model werkt zeer overzichtelijk en bestaat uit negen bouwstenen.

  20. Wildfire Risk Main Model

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — The model combines three modeled fire behavior parameters (rate of spread, flame length, crown fire potential) and one modeled ecological health measure (fire regime...

  1. Lapse Rate Modeling

    DEFF Research Database (Denmark)

    De Giovanni, Domenico

    prepayment models for mortgage backed securities, this paper builds a Rational Expectation (RE) model describing the policyholders' behavior in lapsing the contract. A market model with stochastic interest rates is considered, and the pricing is carried out through numerical approximation...

  2. Lapse rate modeling

    DEFF Research Database (Denmark)

    De Giovanni, Domenico

    2010-01-01

    prepayment models for mortgage backed securities, this paper builds a Rational Expectation (RE) model describing the policyholders' behavior in lapsing the contract. A market model with stochastic interest rates is considered, and the pricing is carried out through numerical approximation...

  3. Quintessence Model Building

    OpenAIRE

    Brax, P.; Martin, J.; Riazuelo, A.

    2001-01-01

    A short review of some of the aspects of quintessence model building is presented. We emphasize the role of tracking models and their possible supersymmetric origin. A short review of some of the aspects of quintessence model building is presented. We emphasize the role of tracking models and their possible supersymmetric origin. A short review of some of the aspects of quintessence model building is presented. We emphasize the role of tracking models and their possible supersymmetric o...

  4. Computational neurogenetic modeling

    CERN Document Server

    Benuskova, Lubica

    2010-01-01

    Computational Neurogenetic Modeling is a student text, introducing the scope and problems of a new scientific discipline - Computational Neurogenetic Modeling (CNGM). CNGM is concerned with the study and development of dynamic neuronal models for modeling brain functions with respect to genes and dynamic interactions between genes. These include neural network models and their integration with gene network models. This new area brings together knowledge from various scientific disciplines, such as computer and information science, neuroscience and cognitive science, genetics and molecular biol

  5. Overuse Injury Assessment Model

    National Research Council Canada - National Science Library

    Stuhmiller, James H; Shen, Weixin; Sih, Bryant

    2005-01-01

    .... Previously, we developed a preliminary model that predicted the stress fracture rate and used biomechanical modeling, nonlinear optimization for muscle force, and bone structural analysis to estimate...

  6. Multilevel modeling using R

    CERN Document Server

    Finch, W Holmes; Kelley, Ken

    2014-01-01

    A powerful tool for analyzing nested designs in a variety of fields, multilevel/hierarchical modeling allows researchers to account for data collected at multiple levels. Multilevel Modeling Using R provides you with a helpful guide to conducting multilevel data modeling using the R software environment.After reviewing standard linear models, the authors present the basics of multilevel models and explain how to fit these models using R. They then show how to employ multilevel modeling with longitudinal data and demonstrate the valuable graphical options in R. The book also describes models fo

  7. Cosmological models without singularities

    International Nuclear Information System (INIS)

    Petry, W.

    1981-01-01

    A previously studied theory of gravitation in flat space-time is applied to homogeneous and isotropic cosmological models. There exist two different classes of models without singularities: (i) ever-expanding models, (ii) oscillating models. The first class contains models with hot big bang. For these models there exist at the beginning of the universe-in contrast to Einstein's theory-very high but finite densities of matter and radiation with a big bang of very short duration. After short time these models pass into the homogeneous and isotropic models of Einstein's theory with spatial curvature equal to zero and cosmological constant ALPHA >= O. (author)

  8. Validated dynamic flow model

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2011-01-01

    model structure suggested by University of Lund the WP4 leader. This particular model structure has the advantages that it fits better into the control design frame work used by WP3-4 compared to the model structures previously developed in WP2. The different model structures are first summarised....... Then issues dealing with optimal experimental design is considered. Finally the parameters are estimated in the chosen static and dynamic models and a validation is performed. Two of the static models, one of them the additive model, explains the data well. In case of dynamic models the suggested additive...

  9. Environmental Modeling Center

    Data.gov (United States)

    Federal Laboratory Consortium — The Environmental Modeling Center provides the computational tools to perform geostatistical analysis, to model ground water and atmospheric releases for comparison...

  10. TRACKING CLIMATE MODELS

    Data.gov (United States)

    National Aeronautics and Space Administration — CLAIRE MONTELEONI*, GAVIN SCHMIDT, AND SHAILESH SAROHA* Climate models are complex mathematical models designed by meteorologists, geophysicists, and climate...

  11. Regularized Structural Equation Modeling

    Science.gov (United States)

    Jacobucci, Ross; Grimm, Kevin J.; McArdle, John J.

    2016-01-01

    A new method is proposed that extends the use of regularization in both lasso and ridge regression to structural equation models. The method is termed regularized structural equation modeling (RegSEM). RegSEM penalizes specific parameters in structural equation models, with the goal of creating easier to understand and simpler models. Although regularization has gained wide adoption in regression, very little has transferred to models with latent variables. By adding penalties to specific parameters in a structural equation model, researchers have a high level of flexibility in reducing model complexity, overcoming poor fitting models, and the creation of models that are more likely to generalize to new samples. The proposed method was evaluated through a simulation study, two illustrative examples involving a measurement model, and one empirical example involving the structural part of the model to demonstrate RegSEM’s utility. PMID:27398019

  12. Integrated Site Model Process Model Report

    International Nuclear Information System (INIS)

    Booth, T.

    2000-01-01

    The Integrated Site Model (ISM) provides a framework for discussing the geologic features and properties of Yucca Mountain, which is being evaluated as a potential site for a geologic repository for the disposal of nuclear waste. The ISM is important to the evaluation of the site because it provides 3-D portrayals of site geologic, rock property, and mineralogic characteristics and their spatial variabilities. The ISM is not a single discrete model; rather, it is a set of static representations that provide three-dimensional (3-D), computer representations of site geology, selected hydrologic and rock properties, and mineralogic-characteristics data. These representations are manifested in three separate model components of the ISM: the Geologic Framework Model (GFM), the Rock Properties Model (RPM), and the Mineralogic Model (MM). The GFM provides a representation of the 3-D stratigraphy and geologic structure. Based on the framework provided by the GFM, the RPM and MM provide spatial simulations of the rock and hydrologic properties, and mineralogy, respectively. Functional summaries of the component models and their respective output are provided in Section 1.4. Each of the component models of the ISM considers different specific aspects of the site geologic setting. Each model was developed using unique methodologies and inputs, and the determination of the modeled units for each of the components is dependent on the requirements of that component. Therefore, while the ISM represents the integration of the rock properties and mineralogy into a geologic framework, the discussion of ISM construction and results is most appropriately presented in terms of the three separate components. This Process Model Report (PMR) summarizes the individual component models of the ISM (the GFM, RPM, and MM) and describes how the three components are constructed and combined to form the ISM

  13. Better models are more effectively connected models

    Science.gov (United States)

    Nunes, João Pedro; Bielders, Charles; Darboux, Frederic; Fiener, Peter; Finger, David; Turnbull-Lloyd, Laura; Wainwright, John

    2016-04-01

    The concept of hydrologic and geomorphologic connectivity describes the processes and pathways which link sources (e.g. rainfall, snow and ice melt, springs, eroded areas and barren lands) to accumulation areas (e.g. foot slopes, streams, aquifers, reservoirs), and the spatial variations thereof. There are many examples of hydrological and sediment connectivity on a watershed scale; in consequence, a process-based understanding of connectivity is crucial to help managers understand their systems and adopt adequate measures for flood prevention, pollution mitigation and soil protection, among others. Modelling is often used as a tool to understand and predict fluxes within a catchment by complementing observations with model results. Catchment models should therefore be able to reproduce the linkages, and thus the connectivity of water and sediment fluxes within the systems under simulation. In modelling, a high level of spatial and temporal detail is desirable to ensure taking into account a maximum number of components, which then enables connectivity to emerge from the simulated structures and functions. However, computational constraints and, in many cases, lack of data prevent the representation of all relevant processes and spatial/temporal variability in most models. In most cases, therefore, the level of detail selected for modelling is too coarse to represent the system in a way in which connectivity can emerge; a problem which can be circumvented by representing fine-scale structures and processes within coarser scale models using a variety of approaches. This poster focuses on the results of ongoing discussions on modelling connectivity held during several workshops within COST Action Connecteur. It assesses the current state of the art of incorporating the concept of connectivity in hydrological and sediment models, as well as the attitudes of modellers towards this issue. The discussion will focus on the different approaches through which connectivity

  14. Modelling bankruptcy prediction models in Slovak companies

    Directory of Open Access Journals (Sweden)

    Kovacova Maria

    2017-01-01

    Full Text Available An intensive research from academics and practitioners has been provided regarding models for bankruptcy prediction and credit risk management. In spite of numerous researches focusing on forecasting bankruptcy using traditional statistics techniques (e.g. discriminant analysis and logistic regression and early artificial intelligence models (e.g. artificial neural networks, there is a trend for transition to machine learning models (support vector machines, bagging, boosting, and random forest to predict bankruptcy one year prior to the event. Comparing the performance of this with unconventional approach with results obtained by discriminant analysis, logistic regression, and neural networks application, it has been found that bagging, boosting, and random forest models outperform the others techniques, and that all prediction accuracy in the testing sample improves when the additional variables are included. On the other side the prediction accuracy of old and well known bankruptcy prediction models is quiet high. Therefore, we aim to analyse these in some way old models on the dataset of Slovak companies to validate their prediction ability in specific conditions. Furthermore, these models will be modelled according to new trends by calculating the influence of elimination of selected variables on the overall prediction ability of these models.

  15. Generalized latent variable modeling multilevel, longitudinal, and structural equation models

    CERN Document Server

    Skrondal, Anders; Rabe-Hesketh, Sophia

    2004-01-01

    This book unifies and extends latent variable models, including multilevel or generalized linear mixed models, longitudinal or panel models, item response or factor models, latent class or finite mixture models, and structural equation models.

  16. Biosphere Model Report

    International Nuclear Information System (INIS)

    M. A. Wasiolek

    2003-01-01

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), the TSPA-LA. The ERMYN model provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs), the reference biosphere, the human receptor, and assumptions (Section 6.2 and Section 6.3); (3) Building a mathematical model using the biosphere conceptual model and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN model compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN model by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); and (8) Validating the ERMYN model by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7)

  17. Biosphere Model Report

    Energy Technology Data Exchange (ETDEWEB)

    D. W. Wu

    2003-07-16

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), the TSPA-LA. The ERMYN model provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs), the reference biosphere, the human receptor, and assumptions (Section 6.2 and Section 6.3); (3) Building a mathematical model using the biosphere conceptual model and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN model compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN model by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); and (8) Validating the ERMYN model by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

  18. Biosphere Model Report

    Energy Technology Data Exchange (ETDEWEB)

    M. A. Wasiolek

    2003-10-27

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), the TSPA-LA. The ERMYN model provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs), the reference biosphere, the human receptor, and assumptions (Section 6.2 and Section 6.3); (3) Building a mathematical model using the biosphere conceptual model and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN model compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN model by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); and (8) Validating the ERMYN model by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

  19. Lumped Thermal Household Model

    DEFF Research Database (Denmark)

    Biegel, Benjamin; Andersen, Palle; Stoustrup, Jakob

    2013-01-01

    a lumped model approach as an alternative to the individual models. In the lumped model, the portfolio is seen as baseline consumption superimposed with an ideal storage of limited power and energy capacity. The benefit of such a lumped model is that the computational effort of flexibility optimization...

  20. The Moody Mask Model

    DEFF Research Database (Denmark)

    Larsen, Bjarke Alexander; Andkjær, Kasper Ingdahl; Schoenau-Fog, Henrik

    2015-01-01

    This paper proposes a new relation model, called "The Moody Mask model", for Interactive Digital Storytelling (IDS), based on Franceso Osborne's "Mask Model" from 2011. This, mixed with some elements from Chris Crawford's Personality Models, is a system designed for dynamic interaction between ch...

  1. The Model Confidence Set

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger; Nason, James M.

    The paper introduces the model confidence set (MCS) and applies it to the selection of models. A MCS is a set of models that is constructed such that it will contain the best model with a given level of confidence. The MCS is in this sense analogous to a confidence interval for a parameter. The MCS...

  2. AIDS Epidemiological models

    Science.gov (United States)

    Rahmani, Fouad Lazhar

    2010-11-01

    The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].

  3. Numerical Modelling of Streams

    DEFF Research Database (Denmark)

    Vestergaard, Kristian

    In recent years there has been a sharp increase in the use of numerical water quality models. Numeric water quality modeling can be divided into three steps: Hydrodynamic modeling for the determination of stream flow and water levels. Modelling of transport and dispersion of a conservative...

  4. A Model for Conversation

    DEFF Research Database (Denmark)

    Ayres, Phil

    2012-01-01

    This essay discusses models. It examines what models are, the roles models perform and suggests various intentions that underlie their construction and use. It discusses how models act as a conversational partner, and how they support various forms of conversation within the conversational activity...

  5. Generic Market Models

    NARCIS (Netherlands)

    R. Pietersz (Raoul); M. van Regenmortel

    2005-01-01

    textabstractCurrently, there are two market models for valuation and risk management of interest rate derivatives, the LIBOR and swap market models. In this paper, we introduce arbitrage-free constant maturity swap (CMS) market models and generic market models featuring forward rates that span

  6. Modeling the Accidental Deaths

    Directory of Open Access Journals (Sweden)

    Mariyam Hafeez

    2008-01-01

    Full Text Available The model for accidental deaths in the city of Lahore has been developed by using a class of Generalized Linear Models. Various link functions have been used in developing the model. The diagnostic checks have been carried out to see the validity of the fitted model.

  7. Cultural Resource Predictive Modeling

    Science.gov (United States)

    2017-10-01

    refining formal, inductive predictive models is the quality of the archaeological and environmental data. To build models efficiently, relevant...geomorphology, and historic information . Lessons Learned: The original model was focused on the identification of prehistoric resources. This...system but uses predictive modeling informally . For example, there is no probability for buried archaeological deposits on the Burton Mesa, but there is

  8. Modelling Railway Interlocking Systems

    DEFF Research Database (Denmark)

    Lindegaard, Morten Peter; Viuf, P.; Haxthausen, Anne Elisabeth

    2000-01-01

    In this report we present a model of interlocking systems, and describe how the model may be validated by simulation. Station topologies are modelled by graphs in which the nodes denote track segments, and the edges denote connectivity for train traÆc. Points and signals are modelled by annotatio...

  9. Lumped-parameter models

    Energy Technology Data Exchange (ETDEWEB)

    Ibsen, Lars Bo; Liingaard, M.

    2006-12-15

    A lumped-parameter model represents the frequency dependent soil-structure interaction of a massless foundation placed on or embedded into an unbounded soil domain. In this technical report the steps of establishing a lumped-parameter model are presented. Following sections are included in this report: Static and dynamic formulation, Simple lumped-parameter models and Advanced lumped-parameter models. (au)

  10. Comparing Active Vision Models

    NARCIS (Netherlands)

    Croon, G.C.H.E. de; Sprinkhuizen-Kuyper, I.G.; Postma, E.O.

    2009-01-01

    Active vision models can simplify visual tasks, provided that they can select sensible actions given incoming sensory inputs. Many active vision models have been proposed, but a comparative evaluation of these models is lacking. We present a comparison of active vision models from two different

  11. Comparing active vision models

    NARCIS (Netherlands)

    Croon, G.C.H.E. de; Sprinkhuizen-Kuyper, I.G.; Postma, E.O.

    2009-01-01

    Active vision models can simplify visual tasks, provided that they can select sensible actions given incoming sensory inputs. Many active vision models have been proposed, but a comparative evaluation of these models is lacking. We present a comparison of active vision models from two different

  12. White Paper on Modelling

    NARCIS (Netherlands)

    Van Bloemendaal, Karen; Dijkema, Gerard P.J.; Woerdman, Edwin; Jong, Mattheus

    2015-01-01

    This White Paper provides an overview of the modelling approaches adopted by the project partners in the EDGaR project 'Understanding Gas Sector Intra- and Inter- Market interactions' (UGSIIMI). The paper addresses three types of models: complementarity modelling, agent-based modelling and property

  13. A Model for Conversation

    DEFF Research Database (Denmark)

    Ayres, Phil

    2012-01-01

    This essay discusses models. It examines what models are, the roles models perform and suggests various intentions that underlie their construction and use. It discusses how models act as a conversational partner, and how they support various forms of conversation within the conversational activity...... of design. Three distinctions are drawn through which to develop this discussion of models in an architectural context. An examination of these distinctions serves to nuance particular characteristics and roles of models, the modelling activity itself and those engaged in it....

  14. Wastewater treatment models

    DEFF Research Database (Denmark)

    Gernaey, Krist; Sin, Gürkan

    2011-01-01

    The state-of-the-art level reached in modeling wastewater treatment plants (WWTPs) is reported. For suspended growth systems, WWTP models have evolved from simple description of biological removal of organic carbon and nitrogen in aeration tanks (ASM1 in 1987) to more advanced levels including...... of WWTP modeling by linking the wastewater treatment line with the sludge handling line in one modeling platform. Application of WWTP models is currently rather time consuming and thus expensive due to the high model complexity, and requires a great deal of process knowledge and modeling expertise...

  15. Wastewater Treatment Models

    DEFF Research Database (Denmark)

    Gernaey, Krist; Sin, Gürkan

    2008-01-01

    The state-of-the-art level reached in modeling wastewater treatment plants (WWTPs) is reported. For suspended growth systems, WWTP models have evolved from simple description of biological removal of organic carbon and nitrogen in aeration tanks (ASM1 in 1987) to more advanced levels including...... the practice of WWTP modeling by linking the wastewater treatment line with the sludge handling line in one modeling platform. Application of WWTP models is currently rather time consuming and thus expensive due to the high model complexity, and requires a great deal of process knowledge and modeling expertise...

  16. Applied stochastic modelling

    CERN Document Server

    Morgan, Byron JT; Tanner, Martin Abba; Carlin, Bradley P

    2008-01-01

    Introduction and Examples Introduction Examples of data sets Basic Model Fitting Introduction Maximum-likelihood estimation for a geometric model Maximum-likelihood for the beta-geometric model Modelling polyspermy Which model? What is a model for? Mechanistic models Function Optimisation Introduction MATLAB: graphs and finite differences Deterministic search methods Stochastic search methods Accuracy and a hybrid approach Basic Likelihood ToolsIntroduction Estimating standard errors and correlations Looking at surfaces: profile log-likelihoods Confidence regions from profiles Hypothesis testing in model selectionScore and Wald tests Classical goodness of fit Model selection biasGeneral Principles Introduction Parameterisation Parameter redundancy Boundary estimates Regression and influence The EM algorithm Alternative methods of model fitting Non-regular problemsSimulation Techniques Introduction Simulating random variables Integral estimation Verification Monte Carlo inference Estimating sampling distributi...

  17. The Hospitable Meal Model

    DEFF Research Database (Denmark)

    Justesen, Lise; Overgaard, Svend Skafte

    2017-01-01

    -ended approach towards meal experiences. The underlying purpose of The Hospitable Meal Model is to provide the basis for creating value for the individuals involved in institutional meal services. The Hospitable Meal Model was developed on the basis of an empirical study on hospital meal experiences explored......This article presents an analytical model that aims to conceptualize how meal experiences are framed when taking into account a dynamic understanding of hospitality: the meal model is named The Hospitable Meal Model. The idea behind The Hospitable Meal Model is to present a conceptual model...... that can serve as a frame for developing hospitable meal competencies among professionals working within the area of institutional foodservices as well as a conceptual model for analysing meal experiences. The Hospitable Meal Model transcends and transforms existing meal models by presenting a more open...

  18. Calibrated Properties Model

    Energy Technology Data Exchange (ETDEWEB)

    C. Ahlers; H. Liu

    2000-03-12

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

  19. Calibrated Properties Model

    Energy Technology Data Exchange (ETDEWEB)

    C.F. Ahlers, H.H. Liu

    2001-12-18

    The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the AMR Development Plan for U0035 Calibrated Properties Model REV00 (CRWMS M&O 1999c). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions.

  20. The Hospitable Meal Model

    DEFF Research Database (Denmark)

    Justesen, Lise; Overgaard, Svend Skafte

    2017-01-01

    This article presents an analytical model that aims to conceptualize how meal experiences are framed when taking into account a dynamic understanding of hospitality: the meal model is named The Hospitable Meal Model. The idea behind The Hospitable Meal Model is to present a conceptual model...... that can serve as a frame for developing hospitable meal competencies among professionals working within the area of institutional foodservices as well as a conceptual model for analysing meal experiences. The Hospitable Meal Model transcends and transforms existing meal models by presenting a more open......-ended approach towards meal experiences. The underlying purpose of The Hospitable Meal Model is to provide the basis for creating value for the individuals involved in institutional meal services. The Hospitable Meal Model was developed on the basis of an empirical study on hospital meal experiences explored...

  1. MulensModel: Microlensing light curves modeling

    Science.gov (United States)

    Poleski, Radoslaw; Yee, Jennifer

    2018-03-01

    MulensModel calculates light curves of microlensing events. Both single and binary lens events are modeled and various higher-order effects can be included: extended source (with limb-darkening), annual microlensing parallax, and satellite microlensing parallax. The code is object-oriented and written in Python3, and requires AstroPy (ascl:1304.002).

  2. Business Models and Business Model Innovation

    DEFF Research Database (Denmark)

    Foss, Nicolai J.; Saebi, Tina

    2018-01-01

    While research on business models and business model innovation continue to exhibit growth, the field is still, even after more than two decades of research, characterized by a striking lack of cumulative theorizing and an opportunistic borrowing of more or less related ideas from neighbouring...

  3. EMC Simulation and Modeling

    Science.gov (United States)

    Takahashi, Takehiro; Schibuya, Noboru

    The EMC simulation is now widely used in design stage of electronic equipment to reduce electromagnetic noise. As the calculated electromagnetic behaviors of the EMC simulator depends on the inputted EMC model of the equipment, the modeling technique is important to obtain effective results. In this paper, simple outline of the EMC simulator and EMC model are described. Some modeling techniques of EMC simulation are also described with an example of the EMC model which is shield box with aperture.

  4. Phenomenology of inflationary models

    Science.gov (United States)

    Olyaei, Abbas

    2018-01-01

    There are many inflationary models compatible with observational data. One can investigate inflationary models by looking at their general features, which are common in most of the models. Here we have investigated some of the single-field models without considering their origin in order to find the phenomenology of them. We have shown how to adjust the simple harmonic oscillator model in order to be in good agreement with observational data.

  5. Multilevel statistical models

    CERN Document Server

    Goldstein, Harvey

    2011-01-01

    This book provides a clear introduction to this important area of statistics. The author provides a wide of coverage of different kinds of multilevel models, and how to interpret different statistical methodologies and algorithms applied to such models. This 4th edition reflects the growth and interest in this area and is updated to include new chapters on multilevel models with mixed response types, smoothing and multilevel data, models with correlated random effects and modeling with variance.

  6. Latent classification models

    DEFF Research Database (Denmark)

    Langseth, Helge; Nielsen, Thomas Dyhre

    2005-01-01

    parametric family ofdistributions.  In this paper we propose a new set of models forclassification in continuous domains, termed latent classificationmodels. The latent classification model can roughly be seen ascombining the \\NB model with a mixture of factor analyzers,thereby relaxing the assumptions...... classification model, and wedemonstrate empirically that the accuracy of the proposed model issignificantly higher than the accuracy of other probabilisticclassifiers....

  7. Geochemistry Model Validation Report: External Accumulation Model

    Energy Technology Data Exchange (ETDEWEB)

    K. Zarrabi

    2001-09-27

    The purpose of this Analysis and Modeling Report (AMR) is to validate the External Accumulation Model that predicts accumulation of fissile materials in fractures and lithophysae in the rock beneath a degrading waste package (WP) in the potential monitored geologic repository at Yucca Mountain. (Lithophysae are voids in the rock having concentric shells of finely crystalline alkali feldspar, quartz, and other materials that were formed due to entrapped gas that later escaped, DOE 1998, p. A-25.) The intended use of this model is to estimate the quantities of external accumulation of fissile material for use in external criticality risk assessments for different types of degrading WPs: U.S. Department of Energy (DOE) Spent Nuclear Fuel (SNF) codisposed with High Level Waste (HLW) glass, commercial SNF, and Immobilized Plutonium Ceramic (Pu-ceramic) codisposed with HLW glass. The scope of the model validation is to (1) describe the model and the parameters used to develop the model, (2) provide rationale for selection of the parameters by comparisons with measured values, and (3) demonstrate that the parameters chosen are the most conservative selection for external criticality risk calculations. To demonstrate the applicability of the model, a Pu-ceramic WP is used as an example. The model begins with a source term from separately documented EQ6 calculations; where the source term is defined as the composition versus time of the water flowing out of a breached waste package (WP). Next, PHREEQC, is used to simulate the transport and interaction of the source term with the resident water and fractured tuff below the repository. In these simulations the primary mechanism for accumulation is mixing of the high pH, actinide-laden source term with resident water; thus lowering the pH values sufficiently for fissile minerals to become insoluble and precipitate. In the final section of the model, the outputs from PHREEQC, are processed to produce mass of accumulation

  8. Geochemistry Model Validation Report: External Accumulation Model

    International Nuclear Information System (INIS)

    Zarrabi, K.

    2001-01-01

    The purpose of this Analysis and Modeling Report (AMR) is to validate the External Accumulation Model that predicts accumulation of fissile materials in fractures and lithophysae in the rock beneath a degrading waste package (WP) in the potential monitored geologic repository at Yucca Mountain. (Lithophysae are voids in the rock having concentric shells of finely crystalline alkali feldspar, quartz, and other materials that were formed due to entrapped gas that later escaped, DOE 1998, p. A-25.) The intended use of this model is to estimate the quantities of external accumulation of fissile material for use in external criticality risk assessments for different types of degrading WPs: U.S. Department of Energy (DOE) Spent Nuclear Fuel (SNF) codisposed with High Level Waste (HLW) glass, commercial SNF, and Immobilized Plutonium Ceramic (Pu-ceramic) codisposed with HLW glass. The scope of the model validation is to (1) describe the model and the parameters used to develop the model, (2) provide rationale for selection of the parameters by comparisons with measured values, and (3) demonstrate that the parameters chosen are the most conservative selection for external criticality risk calculations. To demonstrate the applicability of the model, a Pu-ceramic WP is used as an example. The model begins with a source term from separately documented EQ6 calculations; where the source term is defined as the composition versus time of the water flowing out of a breached waste package (WP). Next, PHREEQC, is used to simulate the transport and interaction of the source term with the resident water and fractured tuff below the repository. In these simulations the primary mechanism for accumulation is mixing of the high pH, actinide-laden source term with resident water; thus lowering the pH values sufficiently for fissile minerals to become insoluble and precipitate. In the final section of the model, the outputs from PHREEQC, are processed to produce mass of accumulation

  9. Crop rotation modelling - A European model intercomparison

    DEFF Research Database (Denmark)

    Kollas, Chris; Kersebaum, Kurt C; Nendel, Claas

    2015-01-01

    crop growth simulation models to predict yields in crop rotations at five sites across Europe under minimal calibration. Crop rotations encompassed 301 seasons of ten crop types common to European agriculture and a diverse set of treatments (irrigation, fertilisation, CO2 concentration, soil types...... accurately than main crops (cereals). The majority of models performed better for the treatments of increased CO2 and nitrogen fertilisation than for irrigation and soil-related treatments. The yield simulation of the multi-model ensemble reduced the error compared to single-model simulations. The low degree...... representation of crop rotations, further research is required to synthesise existing knowledge of the physiology of intermediate crops and of carry-over effects from the preceding to the following crop, and to implement/improve the modelling of processes that condition these effects....

  10. Modelling of an homogeneous equilibrium mixture model

    International Nuclear Information System (INIS)

    Bernard-Champmartin, A.; Poujade, O.; Mathiaud, J.; Mathiaud, J.; Ghidaglia, J.M.

    2014-01-01

    We present here a model for two phase flows which is simpler than the 6-equations models (with two densities, two velocities, two temperatures) but more accurate than the standard mixture models with 4 equations (with two densities, one velocity and one temperature). We are interested in the case when the two-phases have been interacting long enough for the drag force to be small but still not negligible. The so-called Homogeneous Equilibrium Mixture Model (HEM) that we present is dealing with both mixture and relative quantities, allowing in particular to follow both a mixture velocity and a relative velocity. This relative velocity is not tracked by a conservation law but by a closure law (drift relation), whose expression is related to the drag force terms of the two-phase flow. After the derivation of the model, a stability analysis and numerical experiments are presented. (authors)

  11. Model Reduction in Groundwater Modeling and Management

    Science.gov (United States)

    Siade, A. J.; Kendall, D. R.; Putti, M.; Yeh, W. W.

    2008-12-01

    Groundwater management requires the development and implementation of mathematical models that, through simulation, evaluate the effects of anthropogenic impacts on an aquifer system. To obtain high levels of accuracy, one must incorporate high levels of complexity, resulting in computationally demanding models. This study provides a methodology for solving groundwater management problems with reduced computational effort by replacing the large, complex numerical model with a significantly smaller, simpler approximation. This is achieved via Proper Orthogonal Decomposition (POD), where the goal is to project the larger model solution space onto a smaller or reduced subspace in which the management problem will be solved, achieving reductions in computation time of up to three orders of magnitude. Once the solution is obtained in the reduced space with acceptable accuracy, it is then projected back to the full model space. A major challenge when using this method is the definition of the reduced solution subspace. In POD, this subspace is defined based on samples or snapshots taken at specific times from the solution of the full model. In this work we determine when snapshots should be taken on the basis of the exponential behavior of the governing partial differential equation. This selection strategy is then generalized for any groundwater model by obtaining and using the optimal snapshot selection for a simplified, dimensionless model. Protocols are developed to allow the snapshot selection results of the simplified, dimensionless model to be transferred to that of a complex, heterogeneous model with any geometry. The proposed methodology is finally applied to a basin in the Oristano Plain located in the Sardinia Island, Italy.

  12. Model Validation Status Review

    International Nuclear Information System (INIS)

    E.L. Hardin

    2001-01-01

    The primary objective for the Model Validation Status Review was to perform a one-time evaluation of model validation associated with the analysis/model reports (AMRs) containing model input to total-system performance assessment (TSPA) for the Yucca Mountain site recommendation (SR). This review was performed in response to Corrective Action Request BSC-01-C-01 (Clark 2001, Krisha 2001) pursuant to Quality Assurance review findings of an adverse trend in model validation deficiency. The review findings in this report provide the following information which defines the extent of model validation deficiency and the corrective action needed: (1) AMRs that contain or support models are identified, and conversely, for each model the supporting documentation is identified. (2) The use for each model is determined based on whether the output is used directly for TSPA-SR, or for screening (exclusion) of features, events, and processes (FEPs), and the nature of the model output. (3) Two approaches are used to evaluate the extent to which the validation for each model is compliant with AP-3.10Q (Analyses and Models). The approaches differ in regard to whether model validation is achieved within individual AMRs as originally intended, or whether model validation could be readily achieved by incorporating information from other sources. (4) Recommendations are presented for changes to the AMRs, and additional model development activities or data collection, that will remedy model validation review findings, in support of licensing activities. The Model Validation Status Review emphasized those AMRs that support TSPA-SR (CRWMS M and O 2000bl and 2000bm). A series of workshops and teleconferences was held to discuss and integrate the review findings. The review encompassed 125 AMRs (Table 1) plus certain other supporting documents and data needed to assess model validity. The AMRs were grouped in 21 model areas representing the modeling of processes affecting the natural and

  13. Model Validation Status Review

    Energy Technology Data Exchange (ETDEWEB)

    E.L. Hardin

    2001-11-28

    The primary objective for the Model Validation Status Review was to perform a one-time evaluation of model validation associated with the analysis/model reports (AMRs) containing model input to total-system performance assessment (TSPA) for the Yucca Mountain site recommendation (SR). This review was performed in response to Corrective Action Request BSC-01-C-01 (Clark 2001, Krisha 2001) pursuant to Quality Assurance review findings of an adverse trend in model validation deficiency. The review findings in this report provide the following information which defines the extent of model validation deficiency and the corrective action needed: (1) AMRs that contain or support models are identified, and conversely, for each model the supporting documentation is identified. (2) The use for each model is determined based on whether the output is used directly for TSPA-SR, or for screening (exclusion) of features, events, and processes (FEPs), and the nature of the model output. (3) Two approaches are used to evaluate the extent to which the validation for each model is compliant with AP-3.10Q (Analyses and Models). The approaches differ in regard to whether model validation is achieved within individual AMRs as originally intended, or whether model validation could be readily achieved by incorporating information from other sources. (4) Recommendations are presented for changes to the AMRs, and additional model development activities or data collection, that will remedy model validation review findings, in support of licensing activities. The Model Validation Status Review emphasized those AMRs that support TSPA-SR (CRWMS M&O 2000bl and 2000bm). A series of workshops and teleconferences was held to discuss and integrate the review findings. The review encompassed 125 AMRs (Table 1) plus certain other supporting documents and data needed to assess model validity. The AMRs were grouped in 21 model areas representing the modeling of processes affecting the natural and

  14. Modeling for Battery Prognostics

    Science.gov (United States)

    Kulkarni, Chetan S.; Goebel, Kai; Khasin, Michael; Hogge, Edward; Quach, Patrick

    2017-01-01

    For any battery-powered vehicles (be it unmanned aerial vehicles, small passenger aircraft, or assets in exoplanetary operations) to operate at maximum efficiency and reliability, it is critical to monitor battery health as well performance and to predict end of discharge (EOD) and end of useful life (EOL). To fulfil these needs, it is important to capture the battery's inherent characteristics as well as operational knowledge in the form of models that can be used by monitoring, diagnostic, and prognostic algorithms. Several battery modeling methodologies have been developed in last few years as the understanding of underlying electrochemical mechanics has been advancing. The models can generally be classified as empirical models, electrochemical engineering models, multi-physics models, and molecular/atomist. Empirical models are based on fitting certain functions to past experimental data, without making use of any physicochemical principles. Electrical circuit equivalent models are an example of such empirical models. Electrochemical engineering models are typically continuum models that include electrochemical kinetics and transport phenomena. Each model has its advantages and disadvantages. The former type of model has the advantage of being computationally efficient, but has limited accuracy and robustness, due to the approximations used in developed model, and as a result of such approximations, cannot represent aging well. The latter type of model has the advantage of being very accurate, but is often computationally inefficient, having to solve complex sets of partial differential equations, and thus not suited well for online prognostic applications. In addition both multi-physics and atomist models are computationally expensive hence are even less suited to online application An electrochemistry-based model of Li-ion batteries has been developed, that captures crucial electrochemical processes, captures effects of aging, is computationally efficient

  15. Dimension of linear models

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    1996-01-01

    Determination of the proper dimension of a given linear model is one of the most important tasks in the applied modeling work. We consider here eight criteria that can be used to determine the dimension of the model, or equivalently, the number of components to use in the model. Four of these cri......Determination of the proper dimension of a given linear model is one of the most important tasks in the applied modeling work. We consider here eight criteria that can be used to determine the dimension of the model, or equivalently, the number of components to use in the model. Four...... the basic problems in determining the dimension of linear models. Then each of the eight measures are treated. The results are illustrated by examples....

  16. Product and Process Modelling

    DEFF Research Database (Denmark)

    Cameron, Ian T.; Gani, Rafiqul

    This book covers the area of product and process modelling via a case study approach. It addresses a wide range of modelling applications with emphasis on modelling methodology and the subsequent in-depth analysis of mathematical models to gain insight via structural aspects of the models....... These approaches are put into the context of life cycle modelling, where multiscale and multiform modelling is increasingly prevalent in the 21st century. The book commences with a discussion of modern product and process modelling theory and practice followed by a series of case studies drawn from a variety...... to biotechnology applications, food, polymer and human health application areas. The book highlights to important nature of modern product and process modelling in the decision making processes across the life cycle. As such it provides an important resource for students, researchers and industrial practitioners....

  17. Modeling volatility using state space models.

    Science.gov (United States)

    Timmer, J; Weigend, A S

    1997-08-01

    In time series problems, noise can be divided into two categories: dynamic noise which drives the process, and observational noise which is added in the measurement process, but does not influence future values of the system. In this framework, we show that empirical volatilities (the squared relative returns of prices) exhibit a significant amount of observational noise. To model and predict their time evolution adequately, we estimate state space models that explicitly include observational noise. We obtain relaxation times for shocks in the logarithm of volatility ranging from three weeks (for foreign exchange) to three to five months (for stock indices). In most cases, a two-dimensional hidden state is required to yield residuals that are consistent with white noise. We compare these results with ordinary autoregressive models (without a hidden state) and find that autoregressive models underestimate the relaxation times by about two orders of magnitude since they do not distinguish between observational and dynamic noise. This new interpretation of the dynamics of volatility in terms of relaxators in a state space model carries over to stochastic volatility models and to GARCH models, and is useful for several problems in finance, including risk management and the pricing of derivative securities. Data sets used: Olsen & Associates high frequency DEM/USD foreign exchange rates (8 years). Nikkei 225 index (40 years). Dow Jones Industrial Average (25 years).

  18. Mixed species flocking of tits (Parus spp.): a field experiment.

    Science.gov (United States)

    Székely, T; Szép, T; Juhász, T

    1989-03-01

    We tested two general models of flocking behaviour, namely the antipredation model and foraging efficiency model on mixed-species tit flocks (Parus spp.). After food addition the size of mixed-species flocks was significantly less than in the control samples. In the presence of extra food significantly more birds were observed either in monospecific flocks or solitary, than during the control observations. In the presence of a living predator the birds foraged in larger mixed-specifies flocks than during the control observations. In addition, the social behaviour of Great Spotted Woodpecker, Middle Spotted Woodpecker and Nuthatch shifted to mixed-specific flocking. The size of monospecific flocks was independent of both treatments. The density of birds increased significantly after food addition, while in the predator presence the birds tended to leave the forest. These results support the view that both the antipredation model and foraging efficiency model seem to be valid for mixed-species flocking. However, in the case of monospecific flocks, the territory maintenance could be the most important factor.

  19. Empirical Model Building Data, Models, and Reality

    CERN Document Server

    Thompson, James R

    2011-01-01

    Praise for the First Edition "This...novel and highly stimulating book, which emphasizes solving real problems...should be widely read. It will have a positive and lasting effect on the teaching of modeling and statistics in general." - Short Book Reviews This new edition features developments and real-world examples that showcase essential empirical modeling techniques Successful empirical model building is founded on the relationship between data and approximate representations of the real systems that generated that data. As a result, it is essential for researchers who construct these m

  20. Zephyr - the prediction models

    DEFF Research Database (Denmark)

    Nielsen, Torben Skov; Madsen, Henrik; Nielsen, Henrik Aalborg

    2001-01-01

    utilities as partners and users. The new models are evaluated for five wind farms in Denmark as well as one wind farm in Spain. It is shown that the predictions based on conditional parametric models are superior to the predictions obatined by state-of-the-art parametric models.......This paper briefly describes new models and methods for predicationg the wind power output from wind farms. The system is being developed in a project which has the research organization Risø and the department of Informatics and Mathematical Modelling (IMM) as the modelling team and all the Danish...

  1. Models of light nuclei

    International Nuclear Information System (INIS)

    Harvey, M.; Khanna, F.C.

    1975-01-01

    The general problem of what constitutes a physical model and what is known about the free nucleon-nucleon interaction are considered. A time independent formulation of the basic equations is chosen. Construction of the average field in which particles move in a general independent particle model is developed, concentrating on problems of defining the average spherical single particle field for any given nucleus, and methods for construction of effective residual interactions and other physical operators. Deformed shell models and both spherical and deformed harmonic oscillator models are discussed in detail, and connections between spherical and deformed shell models are analyzed. A section on cluster models is included. 11 tables, 21 figures

  2. Building Thermal Models

    Science.gov (United States)

    Peabody, Hume L.

    2017-01-01

    This presentation is meant to be an overview of the model building process It is based on typical techniques (Monte Carlo Ray Tracing for radiation exchange, Lumped Parameter, Finite Difference for thermal solution) used by the aerospace industry This is not intended to be a "How to Use ThermalDesktop" course. It is intended to be a "How to Build Thermal Models" course and the techniques will be demonstrated using the capabilities of ThermalDesktop (TD). Other codes may or may not have similar capabilities. The General Model Building Process can be broken into four top level steps: 1. Build Model; 2. Check Model; 3. Execute Model; 4. Verify Results.

  3. Microsoft tabular modeling cookbook

    CERN Document Server

    Braak, Paul te

    2013-01-01

    This book follows a cookbook style with recipes explaining the steps for developing analytic data using Business Intelligence Semantic Models.This book is designed for developers who wish to develop powerful and dynamic models for users as well as those who are responsible for the administration of models in corporate environments. It is also targeted at analysts and users of Excel who wish to advance their knowledge of Excel through the development of tabular models or who wish to analyze data through tabular modeling techniques. We assume no prior knowledge of tabular modeling

  4. Five models of capitalism

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Bresser-Pereira

    2012-03-01

    Full Text Available Besides analyzing capitalist societies historically and thinking of them in terms of phases or stages, we may compare different models or varieties of capitalism. In this paper I survey the literature on this subject, and distinguish the classification that has a production or business approach from those that use a mainly political criterion. I identify five forms of capitalism: among the rich countries, the liberal democratic or Anglo-Saxon model, the social or European model, and the endogenous social integration or Japanese model; among developing countries, I distinguish the Asian developmental model from the liberal-dependent model that characterizes most other developing countries, including Brazil.

  5. Holographic twin Higgs model.

    Science.gov (United States)

    Geller, Michael; Telem, Ofri

    2015-05-15

    We present the first realization of a "twin Higgs" model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary "mirror" sector at the sigma model scale f and not by the composite states at m_{KK}, naturally allowing for m_{KK} beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

  6. Biosphere Model Report

    Energy Technology Data Exchange (ETDEWEB)

    D.W. Wu; A.J. Smith

    2004-11-08

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), TSPA-LA. The ERMYN provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs) (Section 6.2), the reference biosphere (Section 6.1.1), the human receptor (Section 6.1.2), and approximations (Sections 6.3.1.4 and 6.3.2.4); (3) Building a mathematical model using the biosphere conceptual model (Section 6.3) and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); (8) Validating the ERMYN by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7).

  7. Biosphere Model Report

    International Nuclear Information System (INIS)

    D.W. Wu; A.J. Smith

    2004-01-01

    The purpose of this report is to document the biosphere model, the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), which describes radionuclide transport processes in the biosphere and associated human exposure that may arise as the result of radionuclide release from the geologic repository at Yucca Mountain. The biosphere model is one of the process models that support the Yucca Mountain Project (YMP) Total System Performance Assessment (TSPA) for the license application (LA), TSPA-LA. The ERMYN provides the capability of performing human radiation dose assessments. This report documents the biosphere model, which includes: (1) Describing the reference biosphere, human receptor, exposure scenarios, and primary radionuclides for each exposure scenario (Section 6.1); (2) Developing a biosphere conceptual model using site-specific features, events, and processes (FEPs) (Section 6.2), the reference biosphere (Section 6.1.1), the human receptor (Section 6.1.2), and approximations (Sections 6.3.1.4 and 6.3.2.4); (3) Building a mathematical model using the biosphere conceptual model (Section 6.3) and published biosphere models (Sections 6.4 and 6.5); (4) Summarizing input parameters for the mathematical model, including the uncertainty associated with input values (Section 6.6); (5) Identifying improvements in the ERMYN compared with the model used in previous biosphere modeling (Section 6.7); (6) Constructing an ERMYN implementation tool (model) based on the biosphere mathematical model using GoldSim stochastic simulation software (Sections 6.8 and 6.9); (7) Verifying the ERMYN by comparing output from the software with hand calculations to ensure that the GoldSim implementation is correct (Section 6.10); (8) Validating the ERMYN by corroborating it with published biosphere models; comparing conceptual models, mathematical models, and numerical results (Section 7)

  8. Modelling of Innovation Diffusion

    Directory of Open Access Journals (Sweden)

    Arkadiusz Kijek

    2010-01-01

    Full Text Available Since the publication of the Bass model in 1969, research on the modelling of the diffusion of innovation resulted in a vast body of scientific literature consisting of articles, books, and studies of real-world applications of this model. The main objective of the diffusion model is to describe a pattern of spread of innovation among potential adopters in terms of a mathematical function of time. This paper assesses the state-of-the-art in mathematical models of innovation diffusion and procedures for estimating their parameters. Moreover, theoretical issues related to the models presented are supplemented with empirical research. The purpose of the research is to explore the extent to which the diffusion of broadband Internet users in 29 OECD countries can be adequately described by three diffusion models, i.e. the Bass model, logistic model and dynamic model. The results of this research are ambiguous and do not indicate which model best describes the diffusion pattern of broadband Internet users but in terms of the results presented, in most cases the dynamic model is inappropriate for describing the diffusion pattern. Issues related to the further development of innovation diffusion models are discussed and some recommendations are given. (original abstract

  9. Lie Markov models.

    Science.gov (United States)

    Sumner, J G; Fernández-Sánchez, J; Jarvis, P D

    2012-04-07

    Recent work has discussed the importance of multiplicative closure for the Markov models used in phylogenetics. For continuous-time Markov chains, a sufficient condition for multiplicative closure of a model class is ensured by demanding that the set of rate-matrices belonging to the model class form a Lie algebra. It is the case that some well-known Markov models do form Lie algebras and we refer to such models as "Lie Markov models". However it is also the case that some other well-known Markov models unequivocally do not form Lie algebras (GTR being the most conspicuous example). In this paper, we will discuss how to generate Lie Markov models by demanding that the models have certain symmetries under nucleotide permutations. We show that the Lie Markov models include, and hence provide a unifying concept for, "group-based" and "equivariant" models. For each of two and four character states, the full list of Lie Markov models with maximal symmetry is presented and shown to include interesting examples that are neither group-based nor equivariant. We also argue that our scheme is pleasing in the context of applied phylogenetics, as, for a given symmetry of nucleotide substitution, it provides a natural hierarchy of models with increasing number of parameters. We also note that our methods are applicable to any application of continuous-time Markov chains beyond the initial motivations we take from phylogenetics. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  10. Integrated Medical Model – Chest Injury Model

    Data.gov (United States)

    National Aeronautics and Space Administration — The Exploration Medical Capability (ExMC) Element of NASA's Human Research Program (HRP) developed the Integrated Medical Model (IMM) to forecast the resources...

  11. Traffic & safety statewide model and GIS modeling.

    Science.gov (United States)

    2012-07-01

    Several steps have been taken over the past two years to advance the Utah Department of Transportation (UDOT) safety initiative. Previous research projects began the development of a hierarchical Bayesian model to analyze crashes on Utah roadways. De...

  12. Nonlinear Modeling by Assembling Piecewise Linear Models

    Science.gov (United States)

    Yao, Weigang; Liou, Meng-Sing

    2013-01-01

    To preserve nonlinearity of a full order system over a parameters range of interest, we propose a simple modeling approach by assembling a set of piecewise local solutions, including the first-order Taylor series terms expanded about some sampling states. The work by Rewienski and White inspired our use of piecewise linear local solutions. The assembly of these local approximations is accomplished by assigning nonlinear weights, through radial basis functions in this study. The efficacy of the proposed procedure is validated for a two-dimensional airfoil moving at different Mach numbers and pitching motions, under which the flow exhibits prominent nonlinear behaviors. All results confirm that our nonlinear model is accurate and stable for predicting not only aerodynamic forces but also detailed flowfields. Moreover, the model is robustness-accurate for inputs considerably different from the base trajectory in form and magnitude. This modeling preserves nonlinearity of the problems considered in a rather simple and accurate manner.

  13. Solid Waste Projection Model: Model user's guide

    International Nuclear Information System (INIS)

    Stiles, D.L.; Crow, V.L.

    1990-08-01

    The Solid Waste Projection Model (SWPM) system is an analytical tool developed by Pacific Northwest Laboratory (PNL) for Westinghouse Hanford company (WHC) specifically to address solid waste management issues at the Hanford Central Waste Complex (HCWC). This document, one of six documents supporting the SWPM system, contains a description of the system and instructions for preparing to use SWPM and operating Version 1 of the model. 4 figs., 1 tab

  14. Modeling of System Families

    National Research Council Canada - National Science Library

    Feiler, Peter

    2007-01-01

    .... The Society of Automotive Engineers (SAE) Architecture Analysis & Design Language (AADL) is an industry-standard, architecture-modeling notation specifically designed to support a component- based approach to modeling embedded systems...

  15. Models in Action

    DEFF Research Database (Denmark)

    Juhl, Joakim

    This thesis is about mathematical modelling and technology development. While mathematical modelling has become widely deployed within a broad range of scientific practices, it has also gained a central position within technology development. The intersection of mathematical modelling......-efficiency project, this thesis presents an analysis of the central practices that materialised representative physical modelling and implemented operational regulation models. In order to show how the project’s representative modelling and technology development connected physical theory with concrete problems...... theoretical outset, the existing literature on simulation models, and the study’s methodological and empirical approach. The purpose of this thesis is to describe the central practices that developed regulation technology for industrial production processes and to analyse how mathematical modelling...

  16. CCF model comparison

    International Nuclear Information System (INIS)

    Pulkkinen, U.

    2004-04-01

    The report describes a simple comparison of two CCF-models, the ECLM, and the Beta-model. The objective of the comparison is to identify differences in the results of the models by applying the models in some simple test data cases. The comparison focuses mainly on theoretical aspects of the above mentioned CCF-models. The properties of the model parameter estimates in the data cases is also discussed. The practical aspects in using and estimating CCFmodels in real PSA context (e.g. the data interpretation, properties of computer tools, the model documentation) are not discussed in the report. Similarly, the qualitative CCF-analyses needed in using the models are not discussed in the report. (au)

  17. Modeling EERE deployment programs

    Energy Technology Data Exchange (ETDEWEB)

    Cort, K. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hostick, D. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Belzer, D. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Livingston, O. V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-11-01

    The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address possible improvements to the modeling process, and note gaps in knowledge for future research.

  18. Controlling Modelling Artifacts

    DEFF Research Database (Denmark)

    Smith, Michael James Andrew; Nielson, Flemming; Nielson, Hanne Riis

    2011-01-01

    the possible configurations of the system (for example, by counting the number of components in a certain state). We motivate our methodology with a case study of the LMAC protocol for wireless sensor networks. In particular, we investigate the accuracy of a recently proposed high-level model of LMAC......When analysing the performance of a complex system, we typically build abstract models that are small enough to analyse, but still capture the relevant details of the system. But it is difficult to know whether the model accurately describes the real system, or if its behaviour is due to modelling...... artifacts that were inadvertently introduced. In this paper, we propose a novel methodology to reason about modelling artifacts, given a detailed model and a highlevel (more abstract) model of the same system. By a series of automated abstraction steps, we lift the detailed model to the same state space...

  19. Modeling Fluid Structure Interaction

    National Research Council Canada - National Science Library

    Benaroya, Haym

    2000-01-01

    The principal goal of this program is on integrating experiments with analytical modeling to develop physics-based reduced-order analytical models of nonlinear fluid-structure interactions in articulated naval platforms...

  20. Consistent model driven architecture

    Science.gov (United States)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  1. Protein solubility modeling

    Science.gov (United States)

    Agena, S. M.; Pusey, M. L.; Bogle, I. D.

    1999-01-01

    A thermodynamic framework (UNIQUAC model with temperature dependent parameters) is applied to model the salt-induced protein crystallization equilibrium, i.e., protein solubility. The framework introduces a term for the solubility product describing protein transfer between the liquid and solid phase and a term for the solution behavior describing deviation from ideal solution. Protein solubility is modeled as a function of salt concentration and temperature for a four-component system consisting of a protein, pseudo solvent (water and buffer), cation, and anion (salt). Two different systems, lysozyme with sodium chloride and concanavalin A with ammonium sulfate, are investigated. Comparison of the modeled and experimental protein solubility data results in an average root mean square deviation of 5.8%, demonstrating that the model closely follows the experimental behavior. Model calculations and model parameters are reviewed to examine the model and protein crystallization process. Copyright 1999 John Wiley & Sons, Inc.

  2. Model and code development

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Progress in model and code development for reactor physics calculations is summarized. The codes included CINDER-10, PHROG, RAFFLE GAPP, DCFMR, RELAP/4, PARET, and KENO. Kinetics models for the PBF were developed

  3. LAT Background Models

    Data.gov (United States)

    National Aeronautics and Space Administration — The Galactic model is a spatial and spectral template. The model for the Galactic diffuse emission was developed using spectral line surveys of HI and CO (as a...

  4. World Magnetic Model 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO)...

  5. The ATLAS Analysis Model

    CERN Multimedia

    Amir Farbin

    The ATLAS Analysis Model is a continually developing vision of how to reconcile physics analysis requirements with the ATLAS offline software and computing model constraints. In the past year this vision has influenced the evolution of the ATLAS Event Data Model, the Athena software framework, and physics analysis tools. These developments, along with the October Analysis Model Workshop and the planning for CSC analyses have led to a rapid refinement of the ATLAS Analysis Model in the past few months. This article introduces some of the relevant issues and presents the current vision of the future ATLAS Analysis Model. Event Data Model The ATLAS Event Data Model (EDM) consists of several levels of details, each targeted for a specific set of tasks. For example the Event Summary Data (ESD) stores calorimeter cells and tracking system hits thereby permitting many calibration and alignment tasks, but will be only accessible at particular computing sites with potentially large latency. In contrast, the Analysis...

  6. World Magnetic Model 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO)...

  7. ASC Champ Orbit Model

    DEFF Research Database (Denmark)

    Riis, Troels; Jørgensen, John Leif

    1999-01-01

    This documents describes a test of the implementation of the ASC orbit model for the Champ satellite.......This documents describes a test of the implementation of the ASC orbit model for the Champ satellite....

  8. Laboratory of Biological Modeling

    Data.gov (United States)

    Federal Laboratory Consortium — The Laboratory of Biological Modeling is defined by both its methodologies and its areas of application. We use mathematical modeling in many forms and apply it to a...

  9. Bounding species distribution models

    Directory of Open Access Journals (Sweden)

    Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

    2011-10-01

    Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

  10. Bounding Species Distribution Models

    Science.gov (United States)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  11. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos

    2013-01-01

    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  12. Emissions Modeling Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Emissions Modeling Clearinghouse (EMCH) supports and promotes emissions modeling activities both internal and external to the EPA. Through this site, the EPA...

  13. Differential models in ecology

    International Nuclear Information System (INIS)

    Barco Gomez, Carlos; Barco Gomez, German

    2002-01-01

    The models mathematical writings with differential equations are used to describe the populational behavior through the time of the animal species. These models can be lineal or no lineal. The differential models for unique specie include the exponential pattern of Malthus and the logistical pattern of Verlhust. The lineal differential models to describe the interaction between two species include the competition relationships, predation and symbiosis

  14. Hierarchical Bass model

    Science.gov (United States)

    Tashiro, Tohru

    2014-03-01

    We propose a new model about diffusion of a product which includes a memory of how many adopters or advertisements a non-adopter met, where (non-)adopters mean people (not) possessing the product. This effect is lacking in the Bass model. As an application, we utilize the model to fit the iPod sales data, and so the better agreement is obtained than the Bass model.

  15. GARCH Modelling of Cryptocurrencies

    Directory of Open Access Journals (Sweden)

    Jeffrey Chu

    2017-10-01

    Full Text Available With the exception of Bitcoin, there appears to be little or no literature on GARCH modelling of cryptocurrencies. This paper provides the first GARCH modelling of the seven most popular cryptocurrencies. Twelve GARCH models are fitted to each cryptocurrency, and their fits are assessed in terms of five criteria. Conclusions are drawn on the best fitting models, forecasts and acceptability of value at risk estimates.

  16. Cloud Model Bat Algorithm

    OpenAIRE

    Yongquan Zhou; Jian Xie; Liangliang Li; Mingzhi Ma

    2014-01-01

    Bat algorithm (BA) is a novel stochastic global optimization algorithm. Cloud model is an effective tool in transforming between qualitative concepts and their quantitative representation. Based on the bat echolocation mechanism and excellent characteristics of cloud model on uncertainty knowledge representation, a new cloud model bat algorithm (CBA) is proposed. This paper focuses on remodeling echolocation model based on living and preying characteristics of bats, utilizing the transformati...

  17. Optimization modeling with spreadsheets

    CERN Document Server

    Baker, Kenneth R

    2015-01-01

    An accessible introduction to optimization analysis using spreadsheets Updated and revised, Optimization Modeling with Spreadsheets, Third Edition emphasizes model building skills in optimization analysis. By emphasizing both spreadsheet modeling and optimization tools in the freely available Microsoft® Office Excel® Solver, the book illustrates how to find solutions to real-world optimization problems without needing additional specialized software. The Third Edition includes many practical applications of optimization models as well as a systematic framework that il

  18. Artificial neural network modelling

    CERN Document Server

    Samarasinghe, Sandhya

    2016-01-01

    This book covers theoretical aspects as well as recent innovative applications of Artificial Neural networks (ANNs) in natural, environmental, biological, social, industrial and automated systems. It presents recent results of ANNs in modelling small, large and complex systems under three categories, namely, 1) Networks, Structure Optimisation, Robustness and Stochasticity 2) Advances in Modelling Biological and Environmental Systems and 3) Advances in Modelling Social and Economic Systems. The book aims at serving undergraduates, postgraduates and researchers in ANN computational modelling. .

  19. TENCompetence Domain Model

    NARCIS (Netherlands)

    2006-01-01

    This is the version 1.1 of the TENCompetence Domain Model (version 1.0 released at 19-6-2006; version 1.1 at 9-11-2008). It contains several files: a) a pdf with the model description, b) three jpg files with class models (also in the pdf), c) a MagicDraw zip file with the model itself, d) a release

  20. Photovoltaic sources modeling

    CERN Document Server

    Petrone, Giovanni; Spagnuolo, Giovanni

    2016-01-01

    This comprehensive guide surveys all available models for simulating a photovoltaic (PV) generator at different levels of granularity, from cell to system level, in uniform as well as in mismatched conditions. Providing a thorough comparison among the models, engineers have all the elements needed to choose the right PV array model for specific applications or environmental conditions matched with the model of the electronic circuit used to maximize the PV power production.

  1. Hierarchical Bass model

    International Nuclear Information System (INIS)

    Tashiro, Tohru

    2014-01-01

    We propose a new model about diffusion of a product which includes a memory of how many adopters or advertisements a non-adopter met, where (non-)adopters mean people (not) possessing the product. This effect is lacking in the Bass model. As an application, we utilize the model to fit the iPod sales data, and so the better agreement is obtained than the Bass model

  2. Calibrated Properties Model

    Energy Technology Data Exchange (ETDEWEB)

    J. Wang

    2003-06-24

    The purpose of this Model Report is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Office of Repository Development (ORD). The UZ contains the unsaturated rock layers overlying the repository and host unit, which constitute a natural barrier to flow, and the unsaturated rock layers below the repository which constitute a natural barrier to flow and transport. This work followed, and was planned in, ''Technical Work Plan (TWP) for: Performance Assessment Unsaturated Zone'' (BSC 2002 [160819], Section 1.10.8 [under Work Package (WP) AUZM06, Climate Infiltration and Flow], and Section I-1-1 [in Attachment I, Model Validation Plans]). In Section 4.2, four acceptance criteria (ACs) are identified for acceptance of this Model Report; only one of these (Section 4.2.1.3.6.3, AC 3) was identified in the TWP (BSC 2002 [160819], Table 3-1). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, and drift-scale and mountain-scale coupled-process models from the UZ Flow, Transport and Coupled Processes Department in the Natural Systems Subproject of the Performance Assessment (PA) Project. The Calibrated Properties Model output will also be used by the Engineered Barrier System Department in the Engineering Systems Subproject. The Calibrated Properties Model provides input through the UZ Model and other process models of natural and engineered systems to the Total System Performance Assessment (TSPA) models, in accord with the PA Strategy and Scope in the PA Project of the Bechtel SAIC Company, LLC (BSC). The UZ process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions. UZ flow is a TSPA model component.

  3. Making business models

    DEFF Research Database (Denmark)

    Gudiksen, Sune Klok; Poulsen, Søren Bolvig; Buur, Jacob

    2014-01-01

    Well-established companies are currently struggling to secure profits due to the pressure from new players' business models as they take advantage of communication technology and new business-model configurations. Because of this, the business model research field flourishes currently; however, t...... illustrates how the application of participatory business model design toolsets can open up discussions on alternative scenarios through improvisation, mock-up making and design game playing, before qualitative judgment on the most promising scenario is carried out....

  4. Model Checking Feature Interactions

    DEFF Research Database (Denmark)

    Le Guilly, Thibaut; Olsen, Petur; Pedersen, Thomas

    2015-01-01

    This paper presents an offline approach to analyzing feature interactions in embedded systems. The approach consists of a systematic process to gather the necessary information about system components and their models. The model is first specified in terms of predicates, before being refined to t...... to timed automata. The consistency of the model is verified at different development stages, and the correct linkage between the predicates and their semantic model is checked. The approach is illustrated on a use case from home automation....

  5. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

  6. Model description and evaluation of model performance: DOSDIM model

    International Nuclear Information System (INIS)

    Lewyckyj, N.; Zeevaert, T.

    1996-01-01

    DOSDIM was developed to assess the impact to man from routine and accidental atmospheric releases. It is a compartmental, deterministic, radiological model. For an accidental release, dynamic transfer are used in opposition to a routine release for which equilibrium transfer factors are used. Parameters values were chosen to be conservative. Transfer between compartments are described by first-order differential equations. 2 figs

  7. Produção fora de época da videira 'BRS Clara' sob cultivo protegido Out of season production of 'BRS Clara' seedless grape under protected cultivation

    Directory of Open Access Journals (Sweden)

    Larissa Abgariani Colombo

    2011-02-01

    study aimed to evaluate the out of season production of grapevine 'BRS Clara' on 'IAC 572 Jales' and 'IAC 766 Campinas' rootstocks, submitted to different types of protected cultivation. The randomized block design was used as a statistical model with four replications arranged in a factorial 7x2 (seven kinds of protected cultivation and two rootstocks. The treatments were: a. plastic screen without fungicides for downy mildew; b. plastic screen with fungicides for downy mildew (standard control of the region; c. plastic cover without fungicides for downy mildew; d. plastic cover and 50% of reduction of the standard fungicides for downy mildew; e. plastic cover and 75% of reduction for the standard fungicide mildew; f. plastic cover with phosphite and copper and; g. plastic cover without fungicides. The rootstocks 'IAC 766' and 'IAC 572' are suitable for the production of 'BRS Clara' in north of Parana state; the use of plastic cover allows a reduction up to 75% of the number of applications of fungicides in 'BRS Clara'; the plastic cover itself is not sufficient to prevent the occurrence of downy mildew in bunches under conditions of high humidity.

  8. Urban tree growth modeling

    Science.gov (United States)

    E. Gregory McPherson; Paula J. Peper

    2012-01-01

    This paper describes three long-term tree growth studies conducted to evaluate tree performance because repeated measurements of the same trees produce critical data for growth model calibration and validation. Several empirical and process-based approaches to modeling tree growth are reviewed. Modeling is more advanced in the fields of forestry and...

  9. Classifying variability modeling techniques

    NARCIS (Netherlands)

    Sinnema, Marco; Deelstra, Sybren

    Variability modeling is important for managing variability in software product families, especially during product derivation. In the past few years, several variability modeling techniques have been developed, each using its own concepts to model the variability provided by a product family. The

  10. Climate models and scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Fortelius, C.; Holopainen, E.; Kaurola, J.; Ruosteenoja, K.; Raeisaenen, J. [Helsinki Univ. (Finland). Dept. of Meteorology

    1996-12-31

    In recent years the modelling of interannual climate variability has been studied, the atmospheric energy and water cycles, and climate simulations with the ECHAM3 model. In addition, the climate simulations of several models have been compared with special emphasis in the area of northern Europe

  11. Rock Properties Model

    International Nuclear Information System (INIS)

    Lum, C.

    2004-01-01

    The purpose of this model report is to document the Rock Properties Model version 3.1 with regard to input data, model methods, assumptions, uncertainties and limitations of model results, and qualification status of the model. The report also documents the differences between the current and previous versions and validation of the model. The rock properties model provides mean matrix and lithophysae porosity, and the cross-correlated mean bulk density as direct input to the ''Saturated Zone Flow and Transport Model Abstraction'', MDL-NBS-HS-000021, REV 02 (BSC 2004 [DIRS 170042]). The constraints, caveats, and limitations associated with this model are discussed in Section 6.6 and 8.2. Model validation accomplished by corroboration with data not cited as direct input is discussed in Section 7. The revision of this model report was performed as part of activities being conducted under the ''Technical Work Plan for: The Integrated Site Model, Revision 05'' (BSC 2004 [DIRS 169635]). The purpose of this revision is to bring the report up to current procedural requirements and address the Regulatory Integration Team evaluation comments. The work plan describes the scope, objectives, tasks, methodology, and procedures for this process

  12. THE SLX MODEL

    NARCIS (Netherlands)

    Vega, Solmaria Halleck; Elhorst, J. Paul

    We provide a comprehensive overview of the strengths and weaknesses of different spatial econometric model specifications in terms of spillover effects. Based on this overview, we advocate taking the SLX model as point of departure in case a well-founded theory indicating which model is most

  13. Understandings of 'Modelling'

    DEFF Research Database (Denmark)

    Andresen, Mette

    2007-01-01

    -authentic modelling is also linked with the potentials of exploration of ready-made models as a forerunner for more authentic modelling processes. The discussion includes analysis of an episode of students? work in the classroom, which serves to illustrate how concept formation may be linked to explorations of a non...

  14. Modeling EERE Deployment Programs

    Energy Technology Data Exchange (ETDEWEB)

    Cort, K. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hostick, D. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Belzer, D. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Livingston, O. V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-11-01

    This report compiles information and conclusions gathered as part of the “Modeling EERE Deployment Programs” project. The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address possible improvements to the modeling process, and note gaps in knowledge in which future research is needed.

  15. Models of Business Internationalisation

    Directory of Open Access Journals (Sweden)

    Jurgita Vabinskaitė

    2011-04-01

    Full Text Available The study deals with the theoretical models of business internationalisation: the “Uppsala” Internationalisation Model, modified “Uppsala” model, the Eclectic Paradigm and analysis of transactional costs, Industrial Network approach, the Advantage Package and the Advantage Cycle.Article in Lithuanian

  16. Modelling: Nature and Use

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    Engineering of products and processes is increasingly “model-centric”. Models in their multitudinous forms are ubiquitous, being heavily used for a range of decision making activities across all life cycle phases. This chapter gives an overview of what is a model, the principal activities in the ...

  17. Ecological modeling for all

    OpenAIRE

    Christensen, V.; Pauly, D.

    1996-01-01

    A brief review of the status of the ECOPATH modeling approach and software is presented, with emphasis on the recent release of a Windows version (ECOPATH 3.0), which enables consideration of uncertainties, and sets the stage for simulation modeling using ECOSIM. Modeling of coral reefs is emphasized.

  18. Models selection and fitting

    International Nuclear Information System (INIS)

    Martin Llorente, F.

    1990-01-01

    The models of atmospheric pollutants dispersion are based in mathematic algorithms that describe the transport, diffusion, elimination and chemical reactions of atmospheric contaminants. These models operate with data of contaminants emission and make an estimation of quality air in the area. This model can be applied to several aspects of atmospheric contamination

  19. Loglinear Rasch model tests

    NARCIS (Netherlands)

    Kelderman, Hendrikus

    1984-01-01

    Existing statistical tests for the fit of the Rasch model have been criticized, because they are only sensitive to specific violations of its assumptions. Contingency table methods using loglinear models have been used to test various psychometric models. In this paper, the assumptions of the Rasch

  20. Modeling Epidemic Network Failures

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Fagertun, Anna Manolova

    2013-01-01

    This paper presents the implementation of a failure propagation model for transport networks when multiple failures occur resulting in an epidemic. We model the Susceptible Infected Disabled (SID) epidemic model and validate it by comparing it to analytical solutions. Furthermore, we evaluate...... to evaluate multiple epidemic scenarios in various network types....