Relevant bibliographies by topics / Abundance models

Academic literature on the topic 'Abundance models'

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Published: 10 December 2022
Last updated: 29 January 2023

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Journal articles on the topic "Abundance models"

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Potts, Joanne M., and Jane Elith. "Comparing species abundance models." Ecological Modelling 199, no. 2 (November 2006): 153–63. http://dx.doi.org/10.1016/j.ecolmodel.2006.05.025.

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He, Fangliang, Kevin Gaston, and Jianguo Wu. "On species occupancy-abundance models." Écoscience 9, no. 1 (January 2002): 119–26. http://dx.doi.org/10.1080/11956860.2002.11682698.

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Chave, Jérôme, David Alonso, and Rampal S. Etienne. "Comparing models of species abundance." Nature 441, no. 7089 (May 2006): E1. http://dx.doi.org/10.1038/nature04826.

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Bi, S. L., T. D. Li, L. H. Li, and W. M. Yang. "SOLAR MODELS WITH REVISED ABUNDANCE." Astrophysical Journal 731, no. 2 (April 1, 2011): L42. http://dx.doi.org/10.1088/2041-8205/731/2/l42.

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Duff, Thomas J., Tina L. Bell, and Alan York. "Patterns of plant abundances in natural systems: is there value in modelling both species abundance and distribution?" Australian Journal of Botany 59, no. 8 (2011): 719. http://dx.doi.org/10.1071/bt11017.

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In plant ecology it is common to use biophysical models to predict species distribution; however, spatial quantitative models of plant species remain rare. In practice, occupancy models are often assumed to indicate habitant quality and are used as surrogate abundance models. This study assessed the potential value of quantitative models of plants for ecosystem management applications by assessing patterns of occupancy and abundance within two closely related understorey plant species, Xanthorrhoea australis and X. caespitosa. Vegetation quadrats were surveyed in Eucalyptus woodland and cover-abundances were assessed using a metric pin intersection technique. A zero inflated generalised additive modelling process was used to assess the relationship of species occupancies and cover-abundances to environmental properties. The models were applied to mapped environmental data to create spatial predictions of occupancy and cover-abundance. Both species shared several predictor variables, but differing responses to these variables resulted in mutually exclusive distributions. No significant correlation was observed between occupancy and cover-abundance for X. australis, but strong correlation was evident for X. caespitosa. The strength of the occupancy and abundance relationship was found to differ greatly between the two species and is therefore likely to be species specific. Occupancy models have been used successfully as proxies for habitat quality models of plant species; however where occupancy and abundance of plants are driven by different influences occupancy will be a poor surrogate for abundance. Outcomes may be improved if occupancy models are validated for abundance or quantitative models are developed and tested for individual species.
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Latham, M. Cecilia, A. David M. Latham, Nathan F. Webb, Nicole A. Mccutchen, and Stan Boutin. "Can Occupancy–Abundance Models Be Used to Monitor Wolf Abundance?" PLoS ONE 9, no. 7 (July 23, 2014): e102982. http://dx.doi.org/10.1371/journal.pone.0102982.

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Sequeira, Ana M. M., Camille Mellin, Hector M. Lozano-Montes, Jessica J. Meeuwig, Mathew A. Vanderklift, Michael D. E. Haywood, Russell C. Babcock, and M. Julian Caley. "Challenges of transferring models of fish abundance between coral reefs." PeerJ 6 (April 17, 2018): e4566. http://dx.doi.org/10.7717/peerj.4566.

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Reliable abundance estimates for species are fundamental in ecology, fisheries, and conservation. Consequently, predictive models able to provide reliable estimates for un- or poorly-surveyed locations would prove a valuable tool for management. Based on commonly used environmental and physical predictors, we developed predictive models of total fish abundance and of abundance by fish family for ten representative taxonomic families for the Great Barrier Reef (GBR) using multiple temporal scenarios. We then tested if models developed for the GBR (reference system) could predict fish abundances at Ningaloo Reef (NR; target system), i.e., if these GBR models could be successfully transferred to NR. Models of abundance by fish family resulted in improved performance (e.g., 44.1% <R2 < 50.6% for Acanthuridae) compared to total fish abundance (9% <R2 < 18.6%). However, in contrast with previous transferability obtained for similar models for fish species richness from the GBR to NR, transferability for these fish abundance models was poor. When compared with observations of fish abundance collected in NR, our transferability results had low validation scores (R2 < 6%,p > 0.05). High spatio-temporal variability of patterns in fish abundance at the family and population levels in both reef systems likely affected the transferability of these models. Inclusion of additional predictors with potential direct effects on abundance, such as local fishing effort or topographic complexity, may improve transferability of fish abundance models. However, observations of these local-scale predictors are often not available, and might thereby hinder studies on model transferability and its usefulness for conservation planning and management.
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Fabrizio, Mary C., Jonathan Raz, and Rajesh Ramanath Bandekar. "Using linear models with correlated errors to analyze changes in abundance of Lake Michigan fishes: 1973-1992." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 4 (April 1, 2000): 775–88. http://dx.doi.org/10.1139/f00-020.

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We examined annual changes in relative abundance of Lake Michigan fishes using linear models with correlated errors in space and time. Abundance of bloater (Coregonus hoyi), deepwater sculpin (Myoxocephalus thompsoni), slimy sculpin (Cottus cognatus), alewife (Alosa pseudoharengus), and rainbow smelt (Osmerus mordax) was monitored with bottom trawls at 10 discrete depths (between 18 and 110 m) off eight fixed ports from 1973 to 1992. The model describing abundance included fixed effects of year, port, depth, and interaction terms as well as quadratic and cubic effects of year and depth because changes in abundance were not strictly linear. Observed temporal trends in abundance varied with species and depth. Additionally, trends in alewife and slimy sculpin abundances depended on port. Cubic trends in the abundance of bloater and quadratic trends in deepwater sculpin and rainbow smelt abundances were similar among ports, permitting lakewide inferences for these species. Mean bloater abundance was low throughout the 1970s, increased during the 1980s, and reached high levels by 1990. Mean abundances of deepwater sculpin and rainbow smelt increased from 1973 to the mid-1980s and declined thereafter. The linear model with correlated errors can be readily applied to repeated-measures data from other fixed-station fishery surveys and is appropriate for data exhibiting spatial and temporal autocorrelations.
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Richer, M. G., M. L. McCall, and N. Arimoto. "Oxygen Abundances in Diffuse Ellipticals and the Metallicity-Luminosity Relation for Dwarf Galaxies." Symposium - International Astronomical Union 171 (1996): 439. http://dx.doi.org/10.1017/s0074180900233573.

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Using theoretical models of the planetary nebula populations in galaxies, we investigate whether the current oxygen abundances in bright planetary nebulae can be used to predict the oxygen abundance that persisted in the interstellar medium when star formation stopped. In all galaxies, these models predict that a gap develops between the abundances observed in bright planetary nebulae and those that persisted in the interstellar medium when star formation stopped. This abundance gap depends primarily upon the oxygen abundance achieved in the interstellar medium when star formation stopped, though it also has some sensitivity to the history of star formation. The gap is always less than 0.5dex in these models. For the Milky Way, the predicted abundance gap, 0.14dex, is identical to that observed. The abundance gap magnifies the abundance-related differences between diffuse ellipticals and dwarf irregulars found by Richer & McCall (1995, ApJ, 445, 642). Diffuse ellipticals are confirmed to have larger oxygen abundances than similarly luminous dwarf irregulars, and to have larger [O/Fe] ratios than dwarf irregulars with the same oxygen abundance. The simplest explanation for both of these observations is that diffuse ellipticals formed on shorter time scales than dwarf irregulars. Given this difference in the history of star formation, diffuse ellipticals cannot be the faded remnants of dwarf irregulars.
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PAULUCCI, L., and J. E. HORVATH. "NU-PROCESS IN EXOTIC MODELS." International Journal of Modern Physics D 19, no. 08n10 (August 2010): 1731–35. http://dx.doi.org/10.1142/s0218271810017238.

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The exact physical conditions generating the abundances of r-elements in environments such as supernovae explosions are still under debate. We evaluated the characteristics expected for the neutrino wind in the proposed model of type-II supernova driven by conversion of nuclear matter to strange matter. Neutrinos will change the final abundance of elements after freeze out of r-process nucleosynthesis, specially those close to mass peaks.
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Dissertations / Theses on the topic "Abundance models"

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Jensen, Adam G. "Updated interstellar abundance studies and implications for dust models." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3256457.

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Ensign, William E. "Multiple-scale habitat models of benthic fish abundance in riffles." Diss., Virginia Tech, 1995. http://hdl.handle.net/10919/38204.

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This dissertation examines the relationship between abundances of Roanoke darter, Roanoke logperch, and black jump rock and availability of stream habitat features at three spatial scales in two reaches of the Roanoke River, Virginia. The utility of underwater observation as a method of estimating benthic fish densities is also assessed. Distributions of perpendicular sighting distances indicate models assuming equal sighting probability are not appropriate for benthic species but distance sampling models assuming decreased sighting probability with increased distance from observers provide reasonable alternatives. Abundances estimated using two distance sampling models, a strip transect model, and a backpack electroshocker were strongly correlated. At the microhabitat scale (45 m² cells), differential use of depth, velocity, substrate, and siltation level by all three species during summer low flows was evident. Habitat use characteristics were not transferable, as depths and velocities associated with high fish densities varied between reaches. Univariate and multivariate habitat suitability indices gave similar rankings for combinations of the four habitat variables, but site suitabilities based on these indices were poor predictors of fish abundance. Habitat cells were not selected independently of surrounding habitat characteristics, as fish densities were highest in target cells adjacent to cells with preferred microhabitat characteristics. Roanoke darter and black jumprock abundances were highest at sites where preferred microhabitat patches were non-contiguous while contiguity had no effect on logperch abundance. Multiple regressions showed area of suitable habitat and patch contiguity accounted for 42 %, 34 %, and 33 % of variation in darter, logperch, and jumprock abundances, respectively. Estimates of area of target riffles, area of pools and riffles upstream and downstream of target riffles, and depth, velocity, and substrate characteristics of pools and riffles immediately upstream and downstream of target riffles were obtained. Fish densities were correlated with at least one measure of proximal habitat for all three species. Significant multiple regression models relating fish density to adjacent habitat unit characteristics were also obtained, but the explanatory power of adjacent unit variables varied among small, medium and large riffles and among species. In summary, fish abundance was related to habitat at all spatial scales but explanatory power was limited.
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Forney, Karin A. "Patterns of variability and environmental models of relative abundance for California cetaceans /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9823699.

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Blanchard, Monica R. "Using Network Models to Predict Steelhead Abundance, Middle Fork John Day, OR." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4477.

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In the management of threatened and endangered species, informed population estimates are essential to gage whether or not recovery goals are being met. In the case of Pacific salmonids, this evaluation often involves sampling a small subset of the population and scaling up to estimate larger distinct populations segments. This is made complicated by the fact that fish populations are not evenly distributed along riverscapes but respond to physical and biological stream properties at varying spatial extents. We used rapid assessment survey methods and the River Styles classification to explore fish-habitat relationships at a continuous network scale. Semi-continuous surveys were conducted across nine streams in the upper Middle Fork John Day River watershed and increased the number of sites surveyed eight-fold over other monitoring methods within the watershed. Using this increased sample size and continuous habitat metrics we improved watershed-wide steelhead (Oncorhynchus mykiss) abundance models. We first validated the distinctions among River Styles through a classification analysis using physical metrics measured at the rapid assessment sites. Overall classification accuracy, using a combination of reach and landscape scale metrics, was 88.3% and suggested that River Style classification was identifying variations in physical morphology within the watershed that was quantifiable at the reach scale. Leveraging the continuous River Styles classification of physical habitat and a continuous model of primary production improved the prediction of steelhead abundance across the network. Using random forest regressions, a model that included only habitat metrics resulted in R2 = 0.34, while using the continuous variables improved the model accuracy greatly to R2 = 0.65. Random forest allowed for further investigation into the predictor variables through the analysis of the partial dependence plots and identified a gross primary production threshold, below which production might be limiting steelhead populations. This method also identified the rarest River Style surveyed within the watershed, Confined-Valley Step Cascade, as the morphology that had the largest marginal effect on steelhead. The inherent physical properties and boundary conditions unique to each River Style has the potential to inform fish-habitat relationships across riverscapes and improve abundance estimates on a continuous spatial scale.
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Momal, Raphaëlle. "Network inference from incomplete abundance data Accounting for missing actors in interaction network inference from abundance data Tree‐based inference of species interaction networks from abundance data." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASM017.

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Les réseaux sont utilisés comme outils en microbiologie et en écologie pour représenter des relations entre espèces. Les modèles graphiques gaussiens sont le cadre mathématique dédié à l'inférence des réseaux de dépendances conditionnelles, qui permettent une séparation claires des effets directs et indirects. Cependant, les données observées sont souvent des comptages discrèts qui ne permettent pas l'utilisation de ce modèle. Cette thèse développe une méthodologie pour l'inférence de réseaux à partir de données d'abondance d'espèces. La méthode repose sur une exploration efficace et exhaustive de l'espace des arbres couvrants dans un espace latent des comptages observés, rendue possible par les propriétés algébriques de ces structures.Par ailleurs, il est probable que les comptages observés dépendent d'acteurs non mesurés (espèces ou covariable). Ce phénomène produit des arêtes supplémentaires dans le réseau marginal entre les espèces liées à l'acteur manquant dans le réseau complet, ce qui fausse la suite des analyses. Le second objectif de ce travail est de prendre en compte les acteurs manquants lors de l'inférence de réseau. Les paramètres du modèle proposé sont estimés par une approche variationnelle, qui fournit des éléments d'information pertinents à propos des données non observées
Networks are tools used to represent species relationships in microbiology and ecology. Gaussian Graphical Models provide with a mathematical framework for the inference of conditional dependency networks, which allow for a clear separation of direct and indirect effects. However observed data are often discrete counts and the inference cannot be directly performed with this model. This work develops a methodology for network inference from species observed abundances. The method relies on specific algebraic properties of spanning tree structures to perform an efficient and complete exploration of the space of spanning trees. The inference takes place in a latent space of the observed counts.Then, observed abundances are likely to depend on unmeasured actors (e.g. species or covariate). This results in spurious edges in the marginal network between the species linked to the latter in the complete network, causing inaccurate further analysis. The second objective of this work is to account for missing actors during network inference. To do so we adopt a variational approach yielding valuable insights about the missing actors
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Harris, Danielle V. "Estimating whale abundance using sparse hydrophone arrays." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3463.

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Passive acoustic monitoring has been used to investigate many aspects of marine mammal ecology, although methods to estimate absolute abundance and density using acoustic data have only been developed in recent years. The instrument configuration in an acoustic survey determines which abundance estimation methods can be used. Sparsely distributed arrays of instruments are useful because wide geographic areas can be covered. However, instrument spacing in sparse arrays is such that the same vocalisation will not be detected on multiple instruments, excluding the use of some abundance estimation methods. The aim of this thesis was to explore cetacean abundance and density estimation using novel sparse array datasets, applying existing methods where possible, or developing new approaches. The wealth of data collected by sparse arrays was demonstrated by analysing a 10-year dataset collected by the U.S. Navy's Sound Surveillance System in the north-east Atlantic. Spatial and temporal patterns of blue (Balaenoptera musculus) and fin whale (Balaenoptera physalus) vocal activity were investigated using generalised additive models. Distance sampling-based methods were applied to fin whale calls recorded by an array of Ocean Bottom Seismometers in the north-east Atlantic. Estimated call density was 993 calls/1000 km².hr⁻¹ (CV: 0.39). Animal density could not be estimated because the call rate was unknown. Further development of the call localisation method is required so the current density estimate may be biased. Furthermore, analysing a single day of data resulted in a high variance estimate. Finally, a new simulation-based method developed to estimate density from single hydrophones was applied to blue whale calls recorded in the northern Indian Ocean. Estimated call density was 3 calls/1000 km².hr⁻¹ (CV: 0.17). Again, density of whales could not be estimated as the vocalisation rate was unknown. Lack of biological knowledge poses the greatest limitation to abundance and density estimation using acoustic data.
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Ross, Beth E. "Assessing Changes in the Abundance of the Continental Population of Scaup Using a Hierarchical Spatio-Temporal Model." DigitalCommons@USU, 2012. http://digitalcommons.usu.edu/etd/1147.

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In ecological studies, the goal is often to describe and gain further insight into ecological processes underlying the data collected during observational studies. Because of the nature of observational data, it can often be difficult to separate the variation in the data from the underlying process or `state dynamics.' In order to better address this issue, it is becoming increasingly common for researchers to use hierarchical models. Hierarchical spatial, temporal, and spatio-temporal models allow for the simultaneous modeling of both first and second order processes, thus accounting for underlying autocorrelation in the system while still providing insight into overall spatial and temporal pattern. In this particular study, I use two species of interest, the lesser and greater scaup (Aythya affnis and Aythya marila), as an example of how hierarchical models can be utilized in wildlife management studies. Scaup are the most abundant and widespread diving duck in North America, and are important game species. Since 1978, the continental population of scaup has declined to levels that are 16% below the 1955-2010 average and 34% below the North American Waterfowl Management Plan goal. The greatest decline in abundance of scaup appears to be occurring in the western boreal forest, where populations may have depressed rates of reproductive success, survival, or both. In order to better understand the causes of the decline, and better understand the biology of scaup in general, a level of high importance has been placed on retrospective analyses that determine the spatial and temporal changes in population abundance. In order to implement Bayesian hierarchical models, I used a method called Integrated Nested Laplace Approximation (INLA) to approximate the posterior marginal distribution of the parameters of interest, rather than the more common Markov Chain Monte Carlo (MCMC) approach. Based on preliminary analysis, the data appeared to be overdispersed, containing a disproportionately high number of zeros along with a high variance relative to the mean. Thus, I considered two potential data models, the negative binomial and the zero-inflated negative binomial. Of these models, the zero-inflated negative binomial had the lowest DIC, thus inference was based on this model. Results from this model indicated that a large proportion of the strata were not decreasing (i.e., the estimated slope of the parameter was not significantly different from zero). However, there were important exceptions with strata in the northwest boreal forest and southern prairie parkland habitats. Several strata in the boreal forest habitat had negative slope estimates, indicating a decrease in breeding pairs, while some of the strata in the prairie parkland habitat had positive slope estimates, indicating an increase in this region. Additionally, from looking at plots of individual strata, it seems that the strata experiencing increases in breeding pairs are experiencing dramatic increases. Overall, my results support previous work indicating a decline in population abundance in the northern boreal forest of Canada, and additionally indicate that the population of scaup has increased rapidly in the prairie pothole region since 1957. Yet, by accounting for spatial and temporal autocorrelation in the data, it appears that declines in abundance are not as widespread as previously reported.
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Hanson, John Mark 1955. "Patterns of animal abundance in lakes : the role of competition in the fish-macroinvertebrate relationship." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71975.

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Data taken from the literature were used to develop and evaluate models predicting fish biomass and yield, crustacean zooplankton biomass, and profundal macrobenthos biomass in lakes. Total phosphorus concentration and macrobenthos biomass/mean depth were the best univariate predictors of fish biomass and yield. Phosphorus concentration was also the best predictor of zooplankton and macrobenthos biomass. In experiments testing for inter- and intraspecific competition, conducted in situ at densities based on measured natural fish densities, growth of yellow perch (Perca flavescens) and pumpkinseed (Lepomis gibbosus) reared alone was inversely related to density. Both species primarily ate macroinvertebrates when reared alone. When reared together: perch growth was significantly depressed compared to that of perch reared alone; pumpkinseed growth was equivalent to that of pumpkinseed reared alone; and the diet of perch changed to include food of inferior quality (microcrustaceans) in the presence of the superior competitor, pumpkinseed, whose diet did not change.
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DuFour, Mark R. "Quantification of Variability, Abundance, and Mortality of Maumee River Larval Walleye (Sander vitreus) Using Bayesian Hierarchical Models." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1351976817.

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Sampson, Mark Robert. "Modelling the distribution and abundance of several demersal fish species on the Agulhas Bank, South Africa." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1006207.

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The Agulhas Bank supports a speciose fish community, many of which are commercially important. Despite substantial research being conducted on aspects of their biology spatial aspects of their distribution and abundance in relation to environment parameters has been ignored. This study, therefore, addressed aspects related to the distribution and abundance of representative species on the Agulhas Bank within a Geographic Information System (GIS). Four candidate species were chosen due to their importance either in numbers or unit mass to the South African demersal trawl fishery. The species also shared morphological and taxonomic similarities. The candidate species chosen were the two Cape hake species, shallow-water hake Meluccius capensis, and deep-water hake Merluccius paradoxus, and the two pleuronectiform species being Agulhas sole Austroglossus pectoralis and redspotted tonguesole Cynoglossus zanzibarensis. The use of a GIS was appropriate and allowed for hidden spatial patterns be exposed and illustrated visually, while also facilitating the quantification of the relationships between distribution/abundance and certain environmental predictors using statistical methods The Department of Marine and Coastal Management, Cape Town, supplied biological data in the form of length frequency and biomass information from spring (AprillMay) and autumn (September/October) cruises conducted between 1986 and 1993 on the R. V. Africana. The Council for National Geoscience, Cape Town, supplied sediment data for the entire southern African coastline. Initial exploratory data analysis highlighted potential relationships between environmental variables and abundance for each specie's life-history stanzas. Variations in spatial distribution were found to be significantly different between each life-history stanzas within species. Fish density as a function of the additive effects of the various environmental parameters, including temperature, depth and sediment type, was assessed using a Poisson Generalized Additive Model (GAM), while distribution was analysed with a logistic GAM. A predictive logistic model was then created, taking into consideration the importance of the predictor variables for each species, allowing for predictive estimates to be made for each species by inputting environmental information within the study area. The importance of certain environmental variables influencing distribution and abundance were noted. General patterns indicated that sediment was the most important to both the distribution and abundance of the two pleuronectiform species and juvenile life-history stanzas, while the adult gadoids' distribution and abundance appeared to be depth dependent.
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Books on the topic "Abundance models"

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Sachs, Jeffrey. Natural resource abundance and economic growth. Cambridge, MA: National Bureau of Economic Research, 1995.

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Seber, G. A. F. The estimation of animal abundance and related parameters. 2nd ed. London: Edward Arnold, 1994.

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Kurucz, Robert L. Model stellar atmospheres and real stellar atmospheres and status of the ATLAS12 opacity sampling program and of new programs for Rosseland and for distribution function opacity. [Washington, DC: National Aeronautics and Space Administration, 1996.

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Bishop, James. Determination of hydrocarbon abundances and the strength of eddy mixing in the stratosphere of Neptune: Analysis of UVS solar occultation lightcurves : final report. Fairfax, VA: Computational Physics Incorporated, 1995.

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Bonar, Scott A. Methods for sampling the distribution and abundance of bull trout and Dolly Varden. Olympia, WA: Washington Dept. of Fish and Wildlife, Fish Management Program, Inland Fisheries Investigations, Resource Assessment Division, 1997.

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Bonar, Scott A. Methods for sampling the distribution and abundance of bull trout and Dolly Varden. Olympia, WA: Washington Dept. of Fish and Wildlife, 1997.

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Bonar, Scott A. Methods for sampling the distribution and abundance of bull trout and Dolly Varden. Olympia, WA: Washington Dept. of Fish and Wildlife, 1997.

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O'Donnell, C. F. J. Power to detect trends in abundance of long-tailed bats (Chalinolobus tuberculatus) using counts on line transects. Wellington, N.Z: Dept. of Conservation, 2003.

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Dambacher, Jeffrey M. The distribution and abundance of Great Basin redband trout: An application of variable probability sampling in a 1999 status review. Portland, Or: Fish Division, Oregon Dept. of Fish and Wildlife, 2001.

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Reisenbichler, Reginald Ruben. Use of spawner-recruit relations to evaluate the effect of degraded environment and increased fishing on the abundance of fall-run chinook salmon, Oncorhynchus tshawytscha, in several California streams. Seattle, WA: U.S. Fish and Wildlife Service, Seattle National Fishery Research Center, 1986.

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Book chapters on the topic "Abundance models"

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Hooten, Mevin B., and Trevor J. Hefley. "Abundance Models." In Bringing Bayesian Models to Life, 371–403. Boca Raton, FL : CRC Press, Taylor & Francis Group, 2019.: CRC Press, 2019. http://dx.doi.org/10.1201/9780429243653-24.

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Frigg, Roman. "Taming Abundance." In Models and Theories, 430–63. London: Routledge, 2022. http://dx.doi.org/10.4324/9781003285106-20.

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Harris, DeVerle P. "Geostatistical Crustal Abundance Resource Models." In Quantitative Analysis of Mineral and Energy Resources, 459–88. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-4029-1_27.

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Magurran, Anne E. "Diversity indices and species abundance models." In Ecological Diversity and Its Measurement, 7–45. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-015-7358-0_2.

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Maeder, André. "Chemical Abundances and Models of Wr Stars and Blue Supergiants." In Evolution of Stars: The Photospheric Abundance Connection, 221–33. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3416-3_20.

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Hammarbäck, G. "The Effects of Inhomogeneities in 3-D Models on Abundance Determinations." In Solar and Stellar Granulation, 567–69. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-0911-3_60.

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Gredel, R., E. F. van Dishoeck, and J. H. Black. "Abundance Of Ch+ in Translucent Molecular Clouds: Problems for Shock Models?" In Astrochemistry of Cosmic Phenomena, 153–54. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2761-5_34.

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Reames, Donald V. "Summary and Conclusions." In Solar Energetic Particles, 221–25. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-66402-2_10.

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AbstractIn this chapter we summarize our current understanding of SEPs, of properties of the sites of their origin and of the physical processes that accelerate or modify them. These processes can leave an indelible mark on the abundances of elements, isotopes, ionization states, anisotropies, energy spectra and time profiles of the SEPs. Transport of the ions to us along magnetic fields can impose new variations in large events or even enhance the visibility of the source parameters as the SEPs expand into the heliosphere. We lack physical models that can follow the complexity of SEP abundance variations.
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Adami, Chris, C. Titus Brown, and Michael R. Haggerty. "Abundance-distributions in artificial life and stochastic models: “age and area” revisited." In Advances in Artificial Life, 503–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/3-540-59496-5_321.

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Kumar, N. Samba, K. Ullas Karanth, James D. Nichols, Srinivas Vaidyanathan, Beth Gardner, and Jagdish Krishnaswamy. "Development of Hierarchical Spatial Models for Assessing Ungulate Abundance and Habitat Relationships." In Spatial Dynamics and Ecology of Large Ungulate Populations in Tropical Forests of India, 35–82. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6934-0_2.

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Conference papers on the topic "Abundance models"

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Houdek, G. "Asteroseismic helium abundance determination." In EQUATION-OF-STATE AND PHASE-TRANSITION ISSUES IN MODELS OF ORDINARY ASTROPHYSICAL MATTER. AIP, 2004. http://dx.doi.org/10.1063/1.1828405.

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Goel, Lavika, Daya Gupta, and Vinod Panchal. "Extended Species Abundance Models of Biogeography Based Optimization." In 2012 Fourth International Conference on Computational Intelligence, Modelling and Simulation (CIMSiM). IEEE, 2012. http://dx.doi.org/10.1109/cimsim.2012.30.

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Yang, Bin, Bin Wang, Zongmin Wu, and Qiyong Lu. "Abundance estimation for hyperspectral images based on bilinear mixture models." In 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS). IEEE, 2017. http://dx.doi.org/10.1109/igarss.2017.8127036.

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Walia, Gursimran Singh, and Jeffrey C. Carver. "Evaluation of capture-recapture models for estimating the abundance of naturally-occurring defects." In the Second ACM-IEEE international symposium. New York, New York, USA: ACM Press, 2008. http://dx.doi.org/10.1145/1414004.1414031.

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Matsumoto, Shigeki, Joe Sato, Masato Senami, Masato Yamanaka, and Shaaban Khalil. "Relic abundance of dark matter in universal extra dimension models with right-handed neutrinos." In THE DARK SIDE OF THE UNIVERSE: 4th International Workshop on the Dark Side of the Universe. AIP, 2009. http://dx.doi.org/10.1063/1.3131518.

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George, J. S. "The phosphorus/sulfur abundance ratio as a test of galactic cosmic-ray source models." In SOLAR AND GALACTIC COMPOSITION: A Joint SOHO/ACE Workshop. AIP, 2001. http://dx.doi.org/10.1063/1.1434009.

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Gupta, Daya, Lavika Goel, and Ashish Chopra. "Enhanced heuristic approach for Travelling Tournament Problem based on extended species abundance models of biogeography." In 2014 International Conference on Advances in Computing, Communications and Informatics (ICACCI). IEEE, 2014. http://dx.doi.org/10.1109/icacci.2014.6968336.

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Wesson, Elizabeth N., and Richard H. Rand. "Alternate Models of Replicator Dynamics." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-12046.

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Models of evolutionary dynamics are often approached via the replicator equation, which in its standard form is given by x.i=xifix-ϕ,i = 1,…, n, where xi is the frequency, or relative abundance, of strategy i, fi is its fitness, and ϕ=∑i=1nxifi is the average fitness. A game-theoretic aspect is introduced to the model via the payoff matrix A, where Ai,j is the expected payoff of i vs. j, by taking fi(x) = (A·x)i. This model is based on the exponential model of population growth, ẋi = xifi, with ϕ introduced in order both to hold the total population constant and to model competition between strategies. We analyze the dynamics of analogous models for the replicator equation of the form x.i=gxifi-ϕ, for selected growth functions g.
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Bazinet, Richard. "New methods using natural abundance carbon isotope ratio analysis to measure the turnover of docosahexaenoic acid in preclinical models." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/aloq1878.

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Recently, our laboratory has explored an alternative and cost-effective technique called compound-specific isotope analysis by gas-chromatography isotope ratio mass spectrometry that takes advantage of natural differences in carbon-13 content (13C/12C ratio or d13C) of the food supply to better understand tissue DHA metabolism. However, a lack of variation in the d13C of some molecules limits the methods utility. Here I will present two novel approaches that can be used to circumvent this limitation. Alpha-linolenic acid (ALA), is a well know precursor to docosahexaenoic acid, but it is difficult to find ALA from sources with different d13C. In the first study we fed mice DHA sourced from algae (enriched in carbon 13) chronically and then switched the mice to less enriched fatty acid sources including ALA from flaxseed oil, ALA and stearidonic acid (SDA) from ahiflower oil or DHA derived from fish oil. We show that DHA tissue turnover can be measured from dietary ALA, ALA and SDA or DHA. In the second study upon chronically feeding mice DHA obtained from fish oil we switched mice to a diet either spiked with a small amount (~0.03%) of uniformly labeled DHA to increase the d13C of DHA or to DHA derived from algae. Not only could we differentiate the sources of DHA in the tissues, but the different sources of DHA produced similar tissue half lives. In conclusion, limitations in the natural variance of d13C can be circumvented by changing the d13C content of metabolic products or by adding small amounts of labelled molecules to increase the d13C content.
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Borshcheva, E. V. "The three-phase astrochemical code: modeling of the molecular cloud composition." In Всероссийская с международным участием научная конференция студентов и молодых ученых, посвященная памяти Полины Евгеньевны Захаровой «Астрономия и исследование космического пространства». Ural University Press, 2021. http://dx.doi.org/10.15826/b978-5-7996-3229-8.21.

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We describe the implementation of a three-phase astrochemical model (gas + ice surface + bulk) based on the two-phase Presta code (gas + dust surface) and provide results for calculating the molecular cloud composition. The two- and three-phase models produce significantly different chemical compositions. In particular, CO ice abundance in the three-phase model shows good agreement with the observational data, unlike the two-phase model.
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Reports on the topic "Abundance models"

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Lenz, Mark. RV POSEIDON Fahrtbericht / Cruise Report POS536/Leg 1. GEOMAR, October 2020. http://dx.doi.org/10.3289/geomar_rep_ns_56_2020.

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DIPLANOAGAP: Distribution of Plastics in the North Atlantic Garbage Patch Ponta Delgada (Portugal) – Malaga (Spain) 17.08. – 12.09.2019 The expedition POS 536 is part of a multi-disciplinary research initiative of GEOMAR investigating the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus will be on the vertical transfer of plastic debris from the surface and near-surface waters to the deep sea and on the processes that mediate this transport. The obtained data will help to develop quantitative models that provide information about the level of plastic pollution in the different compartments of the open ocean (surface, water column, seafloor). Furthermore, the effects of plastic debris on marine organisms in the open ocean will be assessed. The cruise will provide data about the: (1) abundance of plastic debris with a minimum size of 100 μm as well as the composition of polymer types in the water column at different depths from the sea surface to the seafloor including the sediment, (2) abundance and composition of plastic debris in organic aggregates (“marine snow”), (3) in pelagic and benthic organisms (invertebrates and fish) and in fecal pellets, (4) abundance and the identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.
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O'Neill, H. B., S. A. Wolfe, and C. Duchesne. Ground ice map of Canada. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330294.

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This Open File presents national-scale mapping of ground ice conditions in Canada. The mapping depicts a first-order estimate of the combined volumetric percentage of excess ice in the top 5 m of permafrost from segregated, wedge, and relict ice. The estimates for the three ice types are based on modelling by O'Neill et al. (2019) (https://doi.org/10.5194/tc-13-753-2019), and informed by available published values of ground ice content and expert knowledge. The mapping offers an improved depiction of ground ice in Canada at a broad scale, incorporating current knowledge on the associations between geological and environmental conditions and ground ice type and abundance. It provides a foundation for hypothesis testing related to broad-scale controls on ground ice formation, preservation, and melt. Additional compilation of quantitative field data on ground ice and improvements to national-scale surficial geology mapping will allow further assessment and refinement of the representation of ground ice in Canada. Continued research will focus on improving the lateral and vertical representation of ground ice required for incorporation into Earth system models and decision-making. Spatial data files of the mapping are available as downloads with this Open File.
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Brenan, J. M., K. Woods, J. E. Mungall, and R. Weston. Origin of chromitites in the Esker Intrusive Complex, Ring of Fire Intrusive Suite, as revealed by chromite trace element chemistry and simple crystallization models. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328981.

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To better constrain the origin of the chromitites associated with the Esker Intrusive Complex (EIC) of the Ring of Fire Intrusive Suite (RoFIS), a total of 50 chromite-bearing samples from the Black Thor, Big Daddy, Blackbird, and Black Label chromite deposits have been analysed for major and trace elements. The samples represent three textural groups, as defined by the relative abundance of cumulate silicate phases and chromite. To provide deposit-specific partition coefficients for modeling, we also report on the results of laboratory experiments to measure olivine- and chromite-melt partitioning of V and Ga, which are two elements readily detectable in the chromites analysed. Comparison of the Cr/Cr+Al and Fe/Fe+Mg of the EIC chromites and compositions from previous experimental studies indicates overlap in Cr/Cr+Al between the natural samples and experiments done at &amp;gt;1400oC, but significant offset of the natural samples to higher Fe/Fe+Mg. This is interpreted to be the result of subsolidus Fe-Mg exchange between chromite and the silicate matrix. However, little change in Cr/Cr+Al from magmatic values, owing to the lack of an exchangeable reservoir for these elements. A comparison of the composition of the EIC chromites and a subset of samples from other tectonic settings reveals a strong similarity to chromites from the similarly-aged Munro Township komatiites. Partition coefficients for V and Ga are consistent with past results in that both elements are compatible in chromite (DV = 2-4; DGa ~ 3), and incompatible in olivine (DV = 0.01-0.14; DGa ~ 0.02), with values for V increasing with decreasing fO2. Simple fractional crystallization models that use these partition coefficients are developed that monitor the change in element behaviour based on the relative proportions of olivine to chromite in the crystallizing assemblage; from 'normal' cotectic proportions involving predominantly olivine, to chromite-only crystallization. Comparison of models to the natural chromite V-Ga array suggests that the overall positive correlation between these two elements is consistent with chromite formed from a Munro Township-like komatiitic magma crystallizing olivine and chromite in 'normal' cotectic proportions, with no evidence of the strong depletion in these elements expected for chromite-only crystallization. The V-Ga array can be explained if the initial magma responsible for chromite formation is slightly reduced with respect to the FMQ oxygen buffer (~FMQ- 0.5), and has assimilated up to ~20% of wall-rock banded iron formation or granodiorite. Despite the evidence for contamination, results indicate that the EIC chromitites crystallized from 'normal' cotectic proportions of olivine to chromite, and therefore no specific causative link is made between contamination and chromitite formation. Instead, the development of near- monomineralic chromite layers likely involves the preferential removal of olivine relative to chromite by physical segregation during magma flow. As suggested for some other chromitite-forming systems, the specific fluid dynamic regime during magma emplacement may therefore be responsible for crystal sorting and chromite accumulation.
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Shen, Jiajian, Tom Abel, Houjun Mo, and Ravi Sheth. An Excursion Set Model of the Cosmic Web: the Abundance of Sheets, Filaments And Halos. Office of Scientific and Technical Information (OSTI), January 2006. http://dx.doi.org/10.2172/878007.

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Spano, Christian, Paolo Natali, Charles Cannon, Suzanne Greene, Osvaldo Urzúa, Carlos Sucre, and Adriana Unzueta. Latin America and the Caribbean 2050: Becoming a Global Low-Carbon Metals and Solutions Hub. Inter-American Development Bank, July 2021. http://dx.doi.org/10.18235/0003412.

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This report evaluates scope 3 emissions along the copper and iron ore value chains and the opportunities that Latin America and the Caribbean (LAC) has to become a low carbon metals and solutions hub. The report presents four carbon emission scenarios that represent different sets of decisions for policy-makers and investors. Two scenarios fall short of aligning with Paris targets: (1) the business as usual (BaU) scenario with no further abatement action; and (2) a BaU scenario with the current level of emission reduction potential from players in the value chain (BaU Possible). The other two scenarios deliver the required carbon reductions to be compliant with the Paris Agreement by 2060, but through different strategies: (3) the BaU Paris scenario. where alignment with Paris targets is achieved by keeping BaU volumes and reducing carbon intensity per tonne of metal; and (4) the Decoupled scenario, where carbon intensity reductions are relaxed and compensated by a reduction in primary supply to align the value chain emissions to a Paris trajectory. All scenarios require LACs leaders to consider investments in low-carbon technology in different degrees. The report argues that, given its competitive position in the cost curve for copper and iron ore and an abundance of enabling factors for low carbon strategies, the region could become a key source of low carbon metals and solutions as long as it is proactive in adopting all the necessary measures from public sector and industry perspectives. Finally, the report concludes that myriad opportunities exist for LAC, including new business models, technologies and products, and that these could yield a greater economic and social contribution to the region than the BaU trajectories.
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O'Neill, H. B., S. A. Wolfe, and C. Duchesne. Preliminary modelling of ground ice abundance in the Slave Geological Province, Northwest Territories and Nunavut. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329815.

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New infrastructure corridors within the Slave Geological Province could provide transportation, electric, and communications links to mineral-rich areas of northern Canada, and connect southern highway systems and Arctic shipping routes. Relatively little information on permafrost and ground ice is available compared to other regions, particularly in the north of the corridor. Improved knowledge of permafrost and ground ice conditions is required to inform planning and management of infrastructure. Work within the Geological Survey of Canada's (GSC) GEM-GeoNorth program includes mapping periglacial terrain features, synthesizing existing permafrost and surficial data, and modelling ground ice conditions along the Yellowknife-Grays Bay corridor. Here we present initial modelling of ground ice abundance in the region using a methodology developed for the national scale Ground ice map of Canada (GIMC), and higher resolution surficial geology mapping. The results highlight the increased estimated abundance of potentially ice-rich deposits compared to the GIMC when using more detailed surficial geology as model inputs.
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Keeling, Ralph. Developing Model Constraints on Northern Extra-Tropical Carbon Cycling Based on measurements of the Abundance and Isotopic Composition of Atmospheric CO2. Office of Scientific and Technical Information (OSTI), December 2014. http://dx.doi.org/10.2172/1165340.

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Schetselaar, E. M., G. Bellefleur, and P. Hunt. Integrated analyses of density, P-wave velocity, lithogeochemistry, and mineralogy to investigate effects of hydrothermal alteration and metamorphism on seismic reflectivity: a summary of results from the Lalor volcanogenic massive-sulfide deposit, Snow Lake, Manitoba. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/327999.

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We present herein a summary of integrated data analyses aimed at investigating the effects of hydrothermal alteration on seismic reflectivity in the footwall of the Lalor volcanogenic massive-sulfide (VMS) deposit, Manitoba. Multivariate analyses of seismic rock properties, lithofacies, and hydrothermal alteration indices show an increase in P-wave velocity for altered volcanic and volcaniclastic lithofacies with respect to their least-altered equivalents. Scanning electron microscopy-energy dispersive X-ray spectrometry analyses of drill-core samples suggest that this P-wave velocity increase is due to the high abundance of high P-wave velocity aluminous minerals, including cordierite, Fe-Mg amphibole, and garnet, which in volcanic rocks are characteristic of VMS-associated hydrothermal alteration metamorphosed in the amphibolite facies. A seismic synthetic profile computed from a simple amphibolite-facies mineral assemblage model, consisting of mafic-felsic host rock contacts, a sulfide ore lens, and a discordant hydrothermal conduit, show enhanced seismic reflections at conduit-host rock contacts in comparison to the equivalent greenschist facies mineral assemblage model. Collectively our results suggest that VMS footwall hydrothermal alteration zones metamorphosed under middle- to upper-amphibolite facies conditions have enhanced potential for seismic detection.
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Kuster, K., C. M. Lesher, and M. G. Houlé. Geology and geochemistry of mafic and ultramafic bodies in the Shebandowan mine area, Wawa-Abitibi terrane: implications for Ni-Cu-(PGE) and Cr-(PGE) mineralization, Ontario and Quebec. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329394.

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The Shebandowan Ni-Cu-(PGE) deposit occurs in the Shebandowan greenstone belt in the Wawa-Abitibi terrane. This deposit is one of a few economic Ni-Cu-(PGE) deposits in the Superior Province and one of a very few deposits worldwide that contains both Ni-Cu-(PGE) and Cr-(PGE) mineralization. The mafic-ultramafic successions in the area comprise abundant flows and sills of tholeiitic basalt and lesser Al-undepleted komatiite (MgO &amp;gt;18 wt%, Al2O3/TiO2 = 15-25), the latter indicating separation from mantle sources at shallow levels. Siliceous high-Mg basalts (MgO 8-12 wt%, SiO2 &amp;gt; 53 wt%, TiO2 &amp;lt; 1.2 wt%, La/Sm[MN] &amp;lt; 1-2) are relatively abundant in the area and likely represent crustally contaminated komatiites. Ultramafic bodies in the Shebandowan mine area comprise at least three or four komatiitic sills (A-B, C, D) and at least two komatiitic flows (E, F), all of which are altered to serpentinites or talc-carbonate schists with relict igneous chromite and rare relict igneous orthopyroxene-clinopyroxene. Unit A-B contains pentlandite-pyrrhotite-chalcopyrite-pyrite-magnetite mineralization, occurring as massive sulfides, sulfide breccias, or stringers, and subeconomic chromite mineralization in contorted massive bands varying from a few millimetres up to 10 metres thick. The localization of massive and semi-massive Ni-Cu-(PGE) ores along the margins of Unit A and the paucity of disseminated and net-textured ores suggest tectonic mobilization. Chromite is typically zoned with Cr-Mg-Al-rich (chromite) cores and Fe-rich (ferrichromite/magnetite) rims due to alteration and/or metamorphism, but rarely contains amoeboid magnetite cores. The thickness of chromite in Unit B is too great to have crystallized in cotectic proportion from the komatiitic magma and a model involving dynamic upgrading of magnetite xenoliths derived from interflow oxide facies iron formations is being tested.
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Weinberg, Zwi G., Adegbola Adesogan, Itzhak Mizrahi, Shlomo Sela, Kwnag Jeong, and Diwakar Vyas. effect of selected lactic acid bacteria on the microbial composition and on the survival of pathogens in the rumen in context with their probiotic effects on ruminants. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598162.bard.

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This research project was performed in context of the apparent probiotic effect of selected lactic acid bacteria (LAB) silage inoculants on the performance of ruminants (improved feed intake, faster live-weight gain, higher milk yields and improved feed efficiency). The overall objective was to find out how LAB affect ruminant performance. The project included several “chapters” as follows: 1. The effect of LAB silage inoculants on the survival of detrimental bacteria in rumen fluid, in vitro study (Weinberg et al., The Volcani Center). An in vitro model was developed to study the interaction between selected LAB and an E. coli strain tagged with green fluorescence protein (GFP) in buffered RF. Results indicated that both LAB inoculants and E. coli survived in the RF for several days; both LAB inoculants and LAB-treated silages did not affect survival of E. coli in rumen fluid in vitro. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the performance of high-lactating cows (Weinberg et al., The Volcani Center). Treatments included control (no additive), Lacobacillusbuchneri40788 (LB), Lactobacillus plantarumMTD1 40027 (LP) and Pediococcuspentosaceus30168 (PP), each applied at 10⁶ cfu/g FM. The silages were included in the TMR of 32 high milking Holstein cows in a controlled feeding experiment. All baled silages were of good quality. The LB silage had the numerically highest acetic acid and were the most stable upon aerobic exposure. The cows fed the LB silages had the highest daily milk yields, percent milk fat and protein. The microbiome of baled wheat silages and changes during ensiling of wheat and corn (Sela et al., The Volcani Center). Bacterial community of the baled silages was dominated mainly of two genera in total, dominated by Lactobacillus and Clostridium_sensu_stricto_12 with 300 other genera at very low abundance. Fungal community was composed mainly of two genera in total, dominated by Candida and Monascuswith 20 other genera at very low abundance. In addition, changes in the microbiome during ensiling of wheat and corn with and without addition of L. plantarumMTD1 was studied in mini-silos. Overall 236 bacterial genera were identified in the fresh corn but after 3 months Lactobacillus outnumbered all other species by acquiring 95% of relative abundance. The wheat silage samples are still under analysis. The effect of applying LAB inoculants at ensiling on survival of E. coli O157:H7 in alfalfa and corn silages(Adesogan et al., University of Florida). E. coli (10⁵ cfu/g) was applied to fresh alfalfa and corn at ensiling with or without L. plantarumor L. buchneri. The pathogen was added again after about 3 moths at the beginning of an aerobic exposure period. The inoculants resulted in faster decrease in pH as compared with the control (no additives) or E. coli alone and therefore, the pathogen was eliminated faster from these silages. After aerobic exposure the pathogen was not detected in the LAB treated silages, whereas it was still present in the E. coli alone samples. 5. The effect of feeding corn silage treated with or without L. buchnerion shedding of E. coli O157:H7 by dairy cows (Adesogan et al., UFL). BARD Report - Project 4704 Page 2 of 12 Five hundred cows from the dairy herd of the University of Florida were screened for E. coli shedding, out of which 14 low and 13 high shedders were selected. These cows were fed a total mixed ration (TMR) which was inoculated with E. coli O157:H7 for 21 days. The TMR included corn silage treated with or without L. buchneri. The inoculated silages were more stable upon aerobic exposure than the control silages; the silage inoculant had no significant effect on any milk or cow blood parameters. However, the silage inoculant tended to reduce shedding of E. coli regardless of high or low shedders (p = 0.06). 6. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the rumen microbiome (Mizrahi et al., BGU). Rumen fluid was sampled throughout the feeding experiment in which inoculated wheat silages were included in the rations. Microbial DNA was subsequently purified from each sample and the 16S rRNA was sequenced, thus obtaining an overview of the microbiome and its dynamic changes for each experimental treatment. We observed an increase in OTU richness in the group which received the baled silage inoculated with Lactobacillus Plantarum(LP). In contrast the group fed Lactobacillus buchneri(LB) inoculated silage resulted in a significant decrease in richness. Lower OTU richness was recently associated in lactating cows with higher performance (Ben Shabatet al., 2016). No significant clustering could be observed between the different inoculation treatments and the control in non metric multi-dimentional scaling, suggesting that the effect of the treatments is not the result of an overall modulation of the microbiome composition but possibly the result of more discrete interactions. Significant phylum level changes in composition also indicates that no broad changes in taxa identity and composition occurred under any treatment A more discrete modulation could be observed in the fold change of several taxonomic groups (genus level analysis), unique to each treatment, before and after the treatment. Of particular interest is the LB treated group, in which several taxa significantly decreased in abundance. BARD Report - Project 4704 Page 3 of 12
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