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Academic literature on the topic 'Attenuation factor'

Author: Grafiati

Published: 4 June 2021

Last updated: 31 May 2022

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Journal articles on the topic "Attenuation factor"

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Chen, Huaizhen. "Estimating elastic properties and attenuation factor from different frequency components of observed seismic data." Geophysical Journal International 220, no. 2 (October 21, 2019): 794–805. http://dx.doi.org/10.1093/gji/ggz476.

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SUMMARY Based on an attenuation model, we first express frequency-dependent P- and S-wave attenuation factors as a function of P-wave maximum attenuation factor, and then we re-express P- and S-wave velocities in anelastic media and derive frequency-dependent stiffness parameters in terms of P-wave maximum attenuation factor. Using the derived stiffness parameters, we propose frequency-dependent reflection coefficient in terms of P- and S-wave moduli at critical frequency and P-wave maximum attenuation factor for the case of an interface separating two attenuating media. Based on the derived reflection coefficient, we establish an approach to utilize different frequency components of observed seismic data to estimate elastic properties (P- and S-wave moduli and density) and attenuation factor, and following a Bayesian framework, we construct the objective function and an iterative method is employed to solve the inversion problem. Tests on synthetic data confirm that the proposed approach makes a stable and robust estimation of unknown parameters in the case of seismic data containing a moderate noise/error. Applying the proposed approach to a real data set illustrates that a reliable attenuation factor is obtained from observed seismic data, and the ability of distinguishing oil-bearing reservoirs is improved combining the estimated elastic properties and P-wave attenuation factor.

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Ribodetti, Alessandra, and Jean Virieux. "Asymptotic theory for imaging the attenuation factor Q." GEOPHYSICS 63, no. 5 (September 1998): 1767–78. http://dx.doi.org/10.1190/1.1444471.

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To describe accurately the propagation of elastic waves for characterizing and monitoring hydrocarbon reservoirs, as well as to obtain improved earth models, it is important to take into account seismic attenuation. We describe a method to estimate anelastic medium properties by a complete SH-waveform inversion. We use an optimization approach based on the iterative minimization of the mismatch between the seismic data and the computed response. To obtain a fast analytical imaging procedure, we include an asymptotic theory for attenuation in a linearized inverse scattering formulation. The forward modeling is solved by the Born approximation for a smooth and attenuative background medium. An asymptotic ray‐tracing method is used to calculate traveltime, amplitude, and attenuation between source, receiver, and scattering points. The resulting method is computationally efficient and allows for a variety of data‐ acquisition geometries, including those with redundant or incomplete source‐receiver coverage. Synthetic examples with realistic surface‐to‐surface geometry show an acceptable convergence in a few iterations when anomaly perturbations are less than 10% of the reference values and when associated diffracting structures are smaller than one‐tenth of the predominant seismic wavelength. Through there remains the fundamental trade‐off between density and shear modulus, the iterative asymptotic inversion is able to recover the elastic parameters (density and shear modulus) and the attenuation factor.

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Vavryčuk, Václav. "Weak anisotropy-attenuation parameters." GEOPHYSICS 74, no. 5 (September 2009): WB203—WB213. http://dx.doi.org/10.1190/1.3173154.

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Velocity anisotropy and attenuation in weakly anisotropic and weakly attenuating structures can be treated uniformly using weak anisotropy-attenuation (WAA) parameters. The WAA parameters are constructed in a way analogous to weak anisotropy (WA) parameters designed for weak elastic anisotropy. The WAA parameters generalize WA parameters by incorporating attenuation effects. They can be represented alternatively by one set of complex values or by two sets of real values. Assuming high-frequency waves and using the first-order perturbation theory, all basic wave quantities such as the slowness vector, the polarization vector, propagation velocity, attenuation, and the quality factor are linear functions of WAA parameters. Numerical modeling shows that perturbation equations have different accuracy for different wave quantities. The propagation velocity usually is calculated with high accuracy. However, the attenuation and quality factor can be reproduced with appreciably lower accuracy. This happens mostly when the strength of velocity anisotropy is higher than 10% and attenuation is moderate or weak [Formula: see text]. In this case, the errors of the attenuation or [Formula: see text]-factor can attain values comparable to the strength of anisotropy or even higher. A simple modification of the equations by including some higher-order perturbations improves accuracy by three to four times.

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Sadat, A., A. Haris, Haryono, A. Riyanto, and G. A. Dharmawan. "Seismic wave attenuation in carbonate rock and its implication to hydrocarbon-bearing reservoir identification, East Java, Indonesia." IOP Conference Series: Earth and Environmental Science 846, no. 1 (September 1, 2021): 012018. http://dx.doi.org/10.1088/1755-1315/846/1/012018.

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Abstract The heterogeneity of carbonate rock properties triggers propagated seismic wave to get some attenuations. This mechanism allows that attenuation can be applied in hydrocarbon exploration to identify lithology, porosity, fluid content and fracture identification. Unfortunately, to measure the degree of attenuation, the sophisticated tools and advanced processing technology are required. Thus, some methods were formulated to estimate attenuation. This study is aimed to estimate and compare attenuation from wireline log interpretation by using four different methods. The study is also supported by a series of exploration wells penetrating Kujung I Formation in northwestern edge of North East Java Basin, Indonesia. The result shows that only Qs from Zhang et al method is overestimate. P-wave quality factor of Klimentos and Zhang methods and scaled quality factor (SQp and SQs) method are sensitive to identify hydrocarbon. Furthermore, lithofacies also affects estimated rock quality factor. The novelty of study is to estimate and compare the attenuation from different method and review its result and application in hydrocarbon identification, especially for carbonate reservoir in North East Java basin, Indonesia. So that, a new understanding of attenuation characteristic in carbonate reservoir contributes to discriminate pore fluid identification in hydrocarbon exploration.

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Sadat, A., A. Haris, Haryono, A. Riyanto, and G. A. Dharmawan. "Seismic wave attenuation in carbonate rock and its implication to hydrocarbon-bearing reservoir identification, East Java, Indonesia." IOP Conference Series: Earth and Environmental Science 846, no. 1 (September 1, 2021): 012018. http://dx.doi.org/10.1088/1755-1315/846/1/012018.

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Abstract The heterogeneity of carbonate rock properties triggers propagated seismic wave to get some attenuations. This mechanism allows that attenuation can be applied in hydrocarbon exploration to identify lithology, porosity, fluid content and fracture identification. Unfortunately, to measure the degree of attenuation, the sophisticated tools and advanced processing technology are required. Thus, some methods were formulated to estimate attenuation. This study is aimed to estimate and compare attenuation from wireline log interpretation by using four different methods. The study is also supported by a series of exploration wells penetrating Kujung I Formation in northwestern edge of North East Java Basin, Indonesia. The result shows that only Qs from Zhang et al method is overestimate. P-wave quality factor of Klimentos and Zhang methods and scaled quality factor (SQp and SQs) method are sensitive to identify hydrocarbon. Furthermore, lithofacies also affects estimated rock quality factor. The novelty of study is to estimate and compare the attenuation from different method and review its result and application in hydrocarbon identification, especially for carbonate reservoir in North East Java basin, Indonesia. So that, a new understanding of attenuation characteristic in carbonate reservoir contributes to discriminate pore fluid identification in hydrocarbon exploration.

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Drwiła, Małgorzata, Miłosz Wcisło, Denis Anikiev, Leo Eisner, and Randy Keller. "Passive seismic measurement of seismic attenuation in Delaware Basin." Leading Edge 38, no. 2 (February 2019): 138–43. http://dx.doi.org/10.1190/tle38020138.1.

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Local earthquake activity can be employed to measure attenuation (the effective quality factor [Q]) and characterize production in the Delaware Basin, Texas, USA. To illustrate this, we employed data from the recently installed Texas Seismic Network (TexNet) seismic stations collected in the west Texas area between April 2017 and March 2018. Earthquake activity in the Delaware Basin has increased in comparison to the previous 20 years, which has resulted in numerous high-quality events suitable for this analysis. The high signal-to-noise ratio events were used to estimate effective Q factors using the peak frequency method on the sediments of the Delaware Basin. The effective attenuation of the sedimentary basin is 90 for P-waves and 140 for S-waves (both with uncertainty of approximately 30), indicating an unusually low attenuation (high Q) for S-waves relative to the P-waves. This is consistent with attenuation of a saturated sedimentary basin because the saturation results in less attenuation of S-waves. Additionally, we observe an increase of the effective Q factor with distance between the station and events consistent with rays sampling the deeper, less-attenuating, and less-saturated portions of the basin and even basement. Inverted effective attenuation coefficients were used to calculate moment magnitudes, which were consistent with those seen in the TexNet array.

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Lin, Dan, and Andrew Eng. "Ground Attenuation Factor Based on Measurements." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 3 (August 1, 2021): 3436–47. http://dx.doi.org/10.3397/in-2021-2405.

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Assumptions made on the ground types between sound sources and receivers can significantly impact the accuracy of environmental outdoor noise prediction. A guideline is provided in ISO 9613-2 and the value of ground factor ranges from 0 to 1, depending on the coverage of porous ground. For example, a ground absorption factor of 1 is suggested for grass ground covers. However, it is unclear if the suggested values are validated. The purpose of this study is to determine the sound absorption of different types of ground by measurements. Field noise measurements were made using an omnidirectional loudspeaker and two microphones on three different types of ground in a quiet neighborhood. One microphone was located 3ft from the loudspeaker to record near field sound levels in 1/3 and 1 octave bands every second. The other microphone was located a few hundred feet away to record far field sound in the same fashion as the near field microphone. The types of ground tested were concrete, grass, and grass with trees. Based on the measurement data, it was found that grass and trees absorb high frequency sound well and a ground factor of 1 may be used for 500Hz and up when using ISO 9613-2 methodology. However, at lower frequencies (125 Hz octave band and below), grassy ground reflects sound the same as concrete surfaces. Trees absorb more low frequency sound than grass, but less than ISO 9613-2 suggested.

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Behura, Jyoti, and Ilya Tsvankin. "Reflection coefficients in attenuative anisotropic media." GEOPHYSICS 74, no. 5 (September 2009): WB193—WB202. http://dx.doi.org/10.1190/1.3142874.

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Such reservoir rocks as tar sands are characterized by significant attenuation and, in some cases, attenuation anisotropy. Most existing attenuation studies are focused on plane-wave attenuation coefficients, which determine the amplitude decay along the raypath of seismic waves. Here we study the influence of attenuation on PP- and PS-wave reflection coefficients for anisotropic media with the main emphasis on transversely isotropic models with a vertical symmetry axis (VTI). Concise analytic solutions obtained by linearizing the exact plane-wave reflection coefficients are verified by numerical modeling. To make a substantial contribution to reflection coefficients, attenuation must be strong, with the quality factor [Formula: see text] not exceeding 10. For such highly attenuative media, it is also necessary to take attenuation anisotropy into account if the magnitude of the Thomsen-styleattenuation-anisotropy parameters is relatively large. In general, the linearized reflection coefficients in attenuative media include velocity-anisotropy parameters but have almost “isotropic” dependence on attenuation. Our formalism also helps evaluate the influence of the inhomogeneity angle (the angle between the real and imaginary parts of the slowness vector) on the reflection coefficients. A nonzero inhomogeneity angle of the incident wave introduces additional terms into the PP- and PS-wave reflection coefficients, which makes conventional amplitude-variation-with-offset (AVO) analysis inadequate for strongly attenuative media. For instance, an incident P-wave with a nonzero inhomogeneity angle generates a mode-converted PS-wave at normal incidence, even if both half-spaces have a horizontal symmetry plane. The developed linearized solutions can be used in AVO inversion for highly attenuative (e.g., gas-sand and heavy-oil) reservoirs.

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Huang, Shao Feng, Hong Ming Shen, and Jia Wang. "A New Method to Discriminate the Inrush Current Based on Prony Analysis." Advanced Materials Research 516-517 (May 2012): 1671–77. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1671.

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The main problem for transformer protection is still how to identify inrush current. The inrush current is likely to occur when the transformer is closed with no-load or when the voltage recovers after fault. False operation may take place for the inrush current is big enough. This paper takes prony analysis as tool to fit the current waveform, and finds that there are two attenuation factors in asymmetrical inrush current’s aperiodic component, one attenuation factor in fault current’s aperiodic component, zero attenuation factor in symmetrical inrush current’s aperiodic component. It is necessary to point out that the two attenuation factors in asymmetrical inrush current are very different in value. Thus, it is possible to identify the inrush current through the number of aperiodic component’s attenuation factor. A large number of MATLAB simulation results prove the method.

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Vavryčuk, Václav. "Ray velocity and ray attenuation in homogeneous anisotropic viscoelastic media." GEOPHYSICS 72, no. 6 (November 2007): D119—D127. http://dx.doi.org/10.1190/1.2768402.

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Asymptotic wave quantities such as ray velocity and ray attenuation are calculated in anisotropic viscoelastic media by using a stationary slowness vector. This vector generally is complex valued and inhomogeneous, and it predicts the complex energy velocity parallel to a ray. To compute the stationary slowness vector, one must find two independent, real-valued unit vectors that specify the directions of its real and imaginary parts. The slowness-vector inhomogeneity affects asymptotic wave quantities and complicates their computation. The critical quantities are attenuation and quality factor ([Formula: see text]-factor); these can vary significantly with the slowness-vector inhomogeneity. If the inhomogeneity is neglected, the attenuation and the [Formula: see text]-factor can be distorted distinctly by errors commensurate to the strength of the velocity anisotropy — as much as tens of percent for sedimentary rocks. The distortion applies to strongly as well as to weakly attenuative media. On the contrary, the ray velocity, which defines the wavefronts and physically corresponds to the energy velocity of a high-frequency signal propagating along a ray, is almost insensitive to the slowness-vector inhomogeneity. Hence, wavefronts can be calculated in a simplified way except for media with extremely strong anisotropy and attenuation.

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Dissertations / Theses on the topic "Attenuation factor"

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Augustin, Lauren Nicole. "Laboratory experiments and numerical modeling of wave attenuation through artificial vegetation." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2563.

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Mendes, Guilherme Martines Teixeira. "Construção e caracterização de linhagens de Salmonella enterica mutantes nos genes de IHF (Integral Host Factor)." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/310659.

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Orientador: Marcelo Brocchi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: O gênero Salmonella spp é formado por bacilos gram-negativos, que podem ser divididos em 3 espécies: S. enterica, S. bongori e S. subterranea. A maioria das sorovariedades patogênicas para o homem está incluída no subgrupo I da espécie S. enterica. A infecção por S. enterica inicia-se com a ingestão de água ou alimentos contaminados. Estes microrganismos são patógenos intracelulares facultativos e, uma vez ingeridos, apresentam a capacidade de aderir e invadir células da mucosa intestinal, preferencialmente células M. Uma vez ultrapassada a mucosa intestinal, S. enterica invade, persiste e prolifera no interior de vacúolos de células do sistema retículo endotelial podendo assim, alcançar diferentes órgãos e tecidos do hospedeiro, causando infecção sistêmica. Sendo assim, linhagens mutantes avirulentas, mas ainda capazes de causar infecção transitória, são boas candidatas a potenciais vacinas vivas orais. Tais mutantes são potenciais carreadores de proteínas heterólogas, compondo, assim, as chamadas vacinas multi-valentes. Que seja de nosso conhecimento, não existem mutantes atenuados de S. enterica desenvolvidos inteiramente no Brasil, havendo necessidade de pagamento de patentes a grupos estrangeiros para sua utilização. Em eucariotos, o DNA cromossômico bacteriano está associado a proteínas (histonas) formando o núcleo, enquanto em procariotos, estas proteínas são denominadas histona-like, formando um nucleóide. Dentre essas proteínas podemos citar a IHF (integration host factor), um heterodímero que controla ou influencia vários processos celulares, como a duplicação e recombinação do DNA, além de regular positiva ou negativamente a expressão de vários genes. Neste estudo, mutantes nulos para os genes himA e himD de IHF foram criados pela técnica de recombinação homóloga mediada pelo sistema ? Red (Datsenko e Wanner, 2000) e testados quanto a atenuação da virulência e capacidade de desencadear resposta imune efetiva e protetora contra a salmonelose murina. Os mutantes também foram caracterizados quanto a diversas características biológicas, como a capacidade de invasão e sobrevivência intracelular, resistência a radicais reativos de oxigênio e nitrogênio, ente outras, sendo os resultados comparados com as respectivas linhagens selvagens. Os mutantes himA e himD de S. enterica foram atenuados e capazes de induzir resposta imune protetora quando desafiados com doses elevadas da linhagem selvagem, indicando que estas linhagens recombinantes são potenciais candidatas a vacinais vivas orais
Abstract: The genus Salmonella sp is formed by gram-negative bacilli, which can be divided into 3 species: S. enterica, S. bongori and S. subterranea. The majority of the serovars pathogenic to humans is included in the subgroup I of the S. enterica species. The infection with S. enterica starts either the ingestion of contaminated water or food. These microorganisms are facultative intracellular pathogens and, once ingested, they have the capacity to adhere and invade cells of the intestinal mucosa, with preference for M cells. Then, S. enterica can invade and proliferate within vacuoles of immune cells, particularly macrophages, achieving different organs and tissues of the host, causing systemic infection. Mutant strains of S. enterica with attenuation of the virulence but that are still able to cause a transient infection, are good candidates for potential live oral vaccines. These mutants are also good carriers of heterologous antigens to cells of the immunological system, been able to induce an effective immunological response. To the best of our knowledge, no mutants of this type were developed in Brazil leading to the needed to pay royalties to foreign groups for their use. In prokaryotes the genomic DNA are associated with a number of proteins, the so called histone-like proteins, with structural and regulatory properties, forming the nucleoid. The IHF (Integration Host Factor) is one of the more abundant histone-like in prokaryotes. IHF is a heterodimeric DNA-binding protein that controls a number of cellular processes, such as DNA duplication and DNA recombination and also modulates the expression of different genes. In this work we constructed recombinant strains of S. enterica mutants for the himA and himD genes that encode for the IHF subunits using the ? Red system (Datsenko and Wanner, 2000) and tested for attenuation and immunogenicity. The mutant strains were also characterized and compared to the parental strains for other biological characteristics such as the capacity to invade and proliferate into eukaryotic cells and to survive to different stress conditions. The S. enterica himA and himD mutant strains were attenuated for virulence and able to induce a protective immunity against the wild type strain of S. enterica indicating that these recombinant strains are candidates to formulate a new live oral vaccine
Mestrado
Ciencias Basicas
Mestre em Clinica Medica

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Vláčil, Martin. "Nové trendy ve výzkumu a vývoji stínění ionizujícího záření." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413216.

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This thesis deals with the problem of shielding ionizing radiation which is a beam that has enough energy to ionize an atom or a molecule of an irradiated substance. This radiation can occur in nuclear facilities such as a nuclear power plant, a particle accelerator, or in X-rays in healthcare. Until now, standard shielding materials, most often lead or concrete, have been used to protect against ionizing radiation. New trends are therefore trying to replace these materials with lighter, more effective and harmless materials. The practical part is focused on measure the data to obtain the basic properties of shielding materials, such as the attenuation factor and the buildup factor. A measuring platform is described here, which can be used to measure the data needed to calculate the attenuation factor and the buildup factor. The measurement results are compared with tabular values to determine the accuracy of the measurements. Furthermore, the results of measurements of five concrete materials from the company MICo, spol. s r.o. To obtain theoretical values, the simulation program MCNP6 was used, in which it is possible to create a model of the measuring platform, which was used in practical measurements. Next the shielding material, source and detector are defined. The result lead again to the data needed to determine the attenuation factor. The results of measurement and simulation data in MCNP6 are evaluated and graphically processed into such a form that it is possible to compare the properties of shielding materials with each other.

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Kefi, Monia. "Coefficients d'attenuation et facteurs de diffusion atomique des elements 46 a 54 dans leur region k." Paris 6, 1988. http://www.theses.fr/1988PA066326.

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Mesure des coefficients d'attenuation des elements de numero atomique 46 a 54 dans le domaine 15 a 45 kev. Determination des parametres de la loi de variation empirique du coefficient d'attenuation en fonction de la longueur d'onde du rayonnement. Determination des facteurs de diffusion anomale vers l'avant, en utilisant la relation de dispersion

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Nunes, Bonnie Ives de Castro. "Estudo comparativo de abordagens de invers?o do fator de qualidade Q." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/18798.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Seismic wave dispersion and attenuation studies have become an important tool for lithology and fluid discrimination in hydrocarbon reservoirs. The processes associated to attenuation are complex and are encapsulated in a single quantitative description called quality factor (Q). The present dissertation has the objective of comparing different approaches of Q determination and is divided in two parts. Firstly, we made performance and robustness tests of three different approaches for Q determination in the frequency domain. They are: peak shift, centroid shift and spectral ratio. All these tests were performed in a three-layered model. In the suite of tests performed here, we varied the thickness, Q and inclination of the layers for propagation pulses with central frequency of 30, 40 and 60 Hz. We found that the centroid shift method is produces robust results for the entire su?te of tests. Secondly, we inverted for Q values using the peak and centroid shift methods using an sequential grid search algorithm. In this case, centroid shift method also produced more robust results than the peak shift method, despite being of slower convergence
Os estudos da dispers?o e da atenua??o das ondas s?smicas t?m se tornado uma ferramenta importante na discrimina??o das litologias e conte?do de fluidos em reservat?rios de hidrocarbonetos. Os processos associados ? atenua??o s?o complexos e sintetizados em uma ?nica descri??o quantitativa chamada fator de qualidade (Q). A presente disserta??o tem o objetivo de comparar diferentes aproxima??es para a determina??o de Q e ? dividido em duas partes. Primeiramente, fizemos um teste de performance e robustez de tr?s m?todos diferentes para a determina??o de Q no dom?nio da freq??ncia. S?o elas: deslocamento de pico, deslocamento de centr?ide e raz?o espectral. Todos os testes foram feitos em um modelo de tr?s camadas. O conjunto de testes aqui realizados consistia em variar a espessura da camada, Q e a inclina??o das camadas para a propaga??o dos pulsos com freq??ncias centrais de 30, 40 e 60 Hz. Pudemos determinar que o m?todo do deslocamento de centr?ide produz os resultados mais robustos para todo o conjunto de testes. Em segundo lugar, invertemos os valores de Q utilizando os m?todos de deslocamento de pico e de centr?ide utilizando um algoritmo de busca seq?encial. Neste caso, o m?todo de centr?ide tamb?m produziu os resultados mais robustos que o m?todo de deslocamento de picos, apesar de ter uma converg?ncia mais lenta

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Lindström, Jan. "Radioluminescence : A simple model for fluorescent layers." Licentiate thesis, Linköpings universitet, Medicinsk radiofysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70539.

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The aim of this thesis is to present a simple model for the radiation to light conversion processes in fluorescent layers as an aid in future developments and applications. Optimisation between sensitivity and spatial resolution for fluorescent layers in digital radiology is a delicate task where the extrinsic efficiency for various phosphors needs to be established for varying parameters. The extrinsic efficiency of a fluorescent layer can be expressed as the ratio of the light energy per unit area at the screen surface to the incident xray energy fluence. Particle size is a critical factor in determining the value of the extrinsic efficiency, but in most models it is not treated as an independent variable. Based on the definition of a light extinction factor (ξ), a model is proposed such that, knowing the intrinsic efficiency η, the particle size and the thickness of a certain make of screen, the extrinsic efficiency can be calculated for an extended range of particle sizes and / or screen thicknesses. The light extinction factor ξ is an optical parameter determined from experimental data on extrinsic efficiency. The proposed model is compared to established methods. Further experiments have confirmed the validity of the model. Monte-Carlo simulations have been utilised to refine the calculations of energy imparted to the phosphor by taking into account the escape of scattered and K-radiation generated in the screen and interface effects at the surfaces. The luminance was measured for a set of in-house manufactured screens of varying thicknesses and particle sizes. Utilising the proposed model, the corresponding calculated values deviated ± 14 %.within the studied range.

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Neves, Meiriele da Silva das 1990. "Caracterização fenotípica e molecular de linhagens atenuadas de Salmonella enterica Typhimurium = Phenotipic and molecular characterization of attenuated strains of Salmonella enterica Typhimurium." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316402.

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Orientador: Marcelo Brocchi
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O gênero Salmonella pertence à família Enterobacteriaceae que agrupa bacilos Gram-negativos, anaeróbios facultativos, fermentadores e geralmente flagelados. S. enterica é um dos patógenos de origem alimentar mais prevalente, sendo que infecções causadas por essa bactéria podem estar relacionadas a praticamente todos os tipos de alimentos. O trabalho foi proposto com o intuito de realizar a caracterização fenotípica e molecular de linhagens atenuadas de Salmonella enterica Typhimurium para genes codificadores de proteínas associadas ao nucleóide (NAPs Nucleoid associated Proteins). As características fenótipicas dos mutantes nulos de Salmonella enterica para os genes ihfA ou ihfB, codificadores das subunidades A e B de IHF, foram avaliadas através de crescimento in vitro, motilidade, sobrevivência frente ao estresse nutricional (sobrevivência em fase estacionária), sob condições ácidas, na presença de sais biliares e quanto à capacidade de invasão e sobrevivência em macrófagos (linhagem J774A.1). Testes de confirmação da atenuação e avaliação da capacidade de induzir proteção em caso de infecção por S. enterica foram realizados utilizando o modelo murino. Os mutantes não apresentaram diferença no crescimento in vitro e na capacidade de sobreviver na presença de sais biliares em comparação com a linhagem selvagem. As linhagens mutantes para os genes ihfA ou ihf ihf ihfB) apresentaram uma menor capacidade de sobrevivência sob condições ácidas quando comparadas com a linhagem selvagem. A motilidade dos mutantes simples também foi reduzida. Os mutantes simples e duplo apresentaram maior capacidade de sobreviver sob estresse nutricional quando comparados com a linhagem selvagem. O mutante para o gene ihfA e o duplo mutante apresentaram um aumento na capacidade de invadir macrófagos. ihf ihfB mostraram uma capacidade aumentada em sobreviver no interior de macrófagos quando comparadas com a linhagem selvagem. Os mutantes nulos viii de Salmonella enterica para os genes ihfA ou ihfB apresentam atenuação, em diferentes graus, quanto à virulência e apresentaram capacidade de induzir proteção no modelo murino de infecção por S. enterica. Esses resultados demonstram que essa proteína apresenta função relacionada com a virulência bacteriana, sendo um importante alvo de estudo na busca de linhagens atenuadas
Abstract: The genus Salmonella belongs to the Enterobacteriaceae family that comprises Gram-negative bacillus, facultative anaerobe, fermenting and generally flagellate. S. enterica is one of the most prevalent food-borne pathogen, and infections caused by this bacterium can be associated to almost all types of food. The work was proposed with the purpose of performing phenotypic and molecular characterization of attenuated strains of Salmonella enterica Typhimurium for genes encoding proteins associated with the nucleoid (NAPs - Nucleoid associated Proteins). The phenotypic characteristics of the null mutants of Salmonella enterica for genes ihfA or ihfB, encoding the A and B subunits of IHF, were evaluated by in vitro growth, motility, survival under nutritional stress (survival in the stationary phase), under acidic conditions, in the presence of bile salts and for the ability of invasion and survival in macrophages (J774A.1 strain). Attenuation tests and evaluation of the capacity to induce protection in case of infection by S. enterica were performed using the murine model. The mutants showed no difference in the in vitro growth and the ability to survive in the presence of bile salts in comparison with the wild type strain. The single mutant for ihfA or ihf ihf ihfB) showed decreased survival under acidic conditions when compared to the wild type strain. Motility of single mutants was also reduced. Single and double mutants showed higher ability to survive under nutritional stress when compared with the wild type strain. The mutant gene for ihfA and the double mutant showed an increased ability to invade ihf ihfB mutants showed an increased ability to survive within macrophages when compared with the wild type strain. Null mutants of Salmonella enterica for ihfA or ihfB genes exhibited attenuation, to varying degrees, for virulence and showed ability to induce protection in a murine model of infection by S. enterica. x These results demonstrate that this protein has function associated to bacterial virulence and is an important subject of study in search for attenuated strains
Mestrado
Genetica de Microorganismos
Mestra em Genética e Biologia Molecular

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Bottomley, Gregory Edward. "Modeling the dynamic behavior of rain attenuation." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/90918.

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This thesis addresses the problem of predicting satellite path rain fade duration statistics for an arbitrary location, frequency, elevation angle and polarization. It summarizes the development of a dynamic stochastic model. From this model a technique is derived for predicting fade duration statistics for one site using measured attenuation data at another site. This technique is evaluated by comparing predicted and experimental results for several locations, frequencies, elevation angles and polarizations.
M.S.

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Guo, Zhilin. "Understanding The Factors Influencing Contaminant Attenuation And Plume Persistence." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/578836.

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The phenomenon of plume persistence was observed for five federal Superfund sites by analysis of historical groundwater-withdrawal and contaminant-concentration data collected from long-term pump-and-treat operations. The potential factors contributing to plume persistence are generally recognized to include incomplete isolation of the source zone, permeability heterogeneity, well-field hydraulics, and non-ideal (rate-limited, nonlinear) desorption. However, the significance of each factor, especially the site-specific contribution is undetermined, which is very important for site development and management. One objective of this study is to quantify the impacts of different factors on mass-removal efficiency. Three-dimensional (3D) numerical models were used to simulate the impact of different well-field configurations on pump-and-treat mass removal. The relationship between reduction in contaminant mass discharge (CMDR) and mass removal (MR) was used as the metric to examine remediation efficiency. Results indicate that (1) even with effort to control the source, residual impact of source can still be a factor causing plume persistence, (2) the well-field configuration has a measurable impact on mass-removal efficiency, which can be muted by the influence of permeability heterogeneity, (3) in terms of permeability heterogeneity, both variance and correlation scale influence the overall mass-removal behavior, (4) the CMDR-MR relationship can be used to quantify the impacts of different factors on mass-removal efficiency at the plume scale. It has been recognized that the use of pump and treat for groundwater remediation will require many decades to attain site closure at most complex sites. Thus, monitored natural attenuation (MNA) and enhanced attenuation (EA) have been widely accepted as alternatives because of their lower cost and sustainable management for large, complex plumes. However, the planning and evaluation of MNA/EA applications require greater levels of characterization data than typically collected. Advanced, innovative methods are required to characterize specific attenuation processes and associated rates to evaluate the feasibility of MNA/EA. Contaminant elution and tracer (CET) tests have been proposed as one such advanced method. Another objective of this study is to investigate the use of modified well-field configurations to enhance the performance of CET tests to collect critical site-specific data that can be used to better delineate attenuation processes and quantify the associated rate coefficients. Three-dimensional numerical models were used to simulate the CET test with specific well-field configurations under different conditions. The results show that the CET test with a nested (two-couplet) well-field configuration can be used to characterize transport and attenuation processes by eliminating the impact of the surrounding plume. The results also show that applying select analytical mass-removal functions can be an efficient method for parameter estimation, as it does not require the use of mathematical transport modeling and does not require the attendant input data that are costly and time-consuming to obtain.

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Misirlisoy, Mine. "Suggestibility to false memories : contributing and attenuating factors /." Full text electronic version of this title, 2007. http://etd.lib.fsu.edu/theses/available/etd-06212007-154450.

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Thesis (Ph. D.)--Florida State University, 2007.
Advisor: Katinka Dijkstra, Florida State University, College of Arts and Sciences, Dept. of Psychology. Title and description from dissertation home page (viewed Oct. 2, 2007). Document formatted into pages; contains viii, 65 pages. Includes bibliographical references.

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Books on the topic "Attenuation factor"

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Stewart, B. M. Factors controlling the release and attenuation of contaminants in a sulfidic tailings impoundment. S.l: s.n, 1993.

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U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Regulatory Applications. and Oak Ridge National Laboratory, eds. New gamma-ray buildup factor data for point kernel calculations: ANS-6.4.3 standard reference data. Washington, DC: Division of Regulatory Applications, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1991.

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U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Regulatory Applications. and Oak Ridge National Laboratory, eds. New gamma-ray buildup factor data for point kernel calculations: ANS-6.4.3 standard reference data. Washington, DC: Division of Regulatory Applications, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1991.

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Munger, Kassandra L. The Epidemiology of Multiple Sclerosis: An Historical Perspective. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199937837.003.0080.

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The descriptive epidemiology has proved to be dynamic with attenuation of the latitude gradient, increase in incidence among women, and changes in the sex ratio over time, indicating that recent changes in environmental factors are responsible. Although we still do not know the causes of MS, or how to prevent it, the current evidence supports causal roles for EBV infection, vitamin D, and cigarette smoking.

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Book chapters on the topic "Attenuation factor"

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Weik, Martin H. "attenuation factor." In Computer Science and Communications Dictionary, 74. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_991.

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Weik, Martin H. "dispersion attenuation factor." In Computer Science and Communications Dictionary, 432. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/1-4020-0613-6_5288.

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Hu, Ren-jie, Guang-yu Zhang, and Li-ping Liao. "The Closeness Centrality Analysis of Fuzzy Social Network Based on Inversely Attenuation Factor." In Advances in Intelligent Systems and Computing, 457–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-38667-1_46.

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Satyam, Neelima, Shambhavi Dube, Raj Banerjee, Srijit Bandyopadhyay, G. R. Reddy, Suzette Payne, and Justin Coleman. "Determination of Anelastic Attenuation Factor (Q) and Decay Factor (K) from Ground Motion Records of the Intra-plate Region." In Developments in Geotechnical Engineering, 353–70. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7721-0_21.

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Raman, Rahul, Mrigakshi Das, Priya Sarmah, Subrata Kumar Dutta, Amarjit Saikia, and Pradip Kumar Sadhu. "Design and Analysis of Series Resonant Inverter-Based Induction Heating Equipment Employing Power Factor Correction for Harmonic Attenuation." In Recent Advances in Power Electronics and Drives, 499–510. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-8586-9_44.

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Schmerr, Lester W. "Material Attenuation and Efficiency Factors." In Fundamentals of Ultrasonic Nondestructive Evaluation, 283–304. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4899-0142-2_9.

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Blom, G., E. H. S. van Duin, and J. E. Vermaat. "Factors contributing to light attenuation in Lake Veluwe." In Lake Veluwe, a Macrophyte-dominated System under Eutrophication Stress, 158–74. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-2032-6_10.

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Steensma, G. J., and N. N. Biswas. "Frequency Dependent Characteristics of Coda Wave Quality Factor in Central and Southcentral Alaska." In Scattering and Attenuations of Seismic Waves, Part I, 295–307. Basel: Birkhäuser Basel, 1988. http://dx.doi.org/10.1007/978-3-0348-7722-0_16.

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Blessing, Heike, Markus Bareiss, Sinje Jankowski, Zao Dung Ling, Paul Carvey, Johannes Schwarz, and Alexander Storch. "Attenuation of Levodopa-Induced Toxicity in Primary Dopamine Neurons by Catechol-O-Methyltransferase Inhibition." In Neurotoxic Factors in Parkinson’s Disease and Related Disorders, 295–300. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-1269-1_28.

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Zheng, Mingpo, Zhifeng Liu, Ying Li, Tao Zhang, Jingjing Xu, and Yanhong Cheng. "Experimental Study on Influence Factors of Clamping Force Attenuation of Threaded Fastener." In Advances in Mechanical Design, 961–71. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7381-8_60.

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Conference papers on the topic "Attenuation factor"

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Khomenko, S. I., V. L. Kostina, I. M. Mytsenko, and A. N. Roenko. "UHF Radio Wave Attenuation Factor Database." In INTERNATIONAL SYMPOSIUM ON RAINFALL RATE AND RADIO WAVE PROPAGATION (ISRR '07). AIP, 2007. http://dx.doi.org/10.1063/1.2767034.

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Ohtsu, S., M. Mukai, S. Kobayas, K. Tanakajima, S. Kawashima, J. Kawano, and A. Maeda. "Analysis of correction factor for site attenuation." In 17th International Zurich Symposium on Electromagnetic Compatibility. IEEE, 2006. http://dx.doi.org/10.1109/emczur.2006.214976.

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Kong, X., and V. Solo. "Effects of attenuation factor on adaptive time delay estimation." In [Proceedings] ICASSP 91: 1991 International Conference on Acoustics, Speech, and Signal Processing. IEEE, 1991. http://dx.doi.org/10.1109/icassp.1991.150825.

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Bai, Wenling, Lilin Dan, Yue Xiao, and Shaoqian Li. "Attenuation Factor Analysis for OFDM Signals with Peak Cancellation." In 2009 IEEE 69th Vehicular Technology Conference Spring. IEEE, 2009. http://dx.doi.org/10.1109/vetecs.2009.5073408.

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Hu, G. Y., Z. J. Wang, J. Y. Zhang, N. Tian, H. C. Dong, and R. Z. Li. "Formation Quality Factor Estimation Based on Energy Attenuation Characteristics." In 79th EAGE Conference and Exhibition 2017. Netherlands: EAGE Publications BV, 2017. http://dx.doi.org/10.3997/2214-4609.201701331.

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Irani Mehr, M., and M. M. Abedi. "Random Noise Attenuation Using Variable Q-Factor Wavelet Transform." In 79th EAGE Conference and Exhibition 2017. Netherlands: EAGE Publications BV, 2017. http://dx.doi.org/10.3997/2214-4609.201701062.

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Maeda, Atsuya, and Shigeru Takeya. "New Correction Factor for High-Precision Open-Site Attenuation Calculation." In 1985 IEEE International Symposium on Electromagnetic Compatibility. IEEE, 1985. http://dx.doi.org/10.1109/isemc.1985.7566938.

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Kiani, A. "Energy Attenuation Analysis and Quality Factor in Direct Hydrocarbon Detection." In 72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010. European Association of Geoscientists & Engineers, 2010. http://dx.doi.org/10.3997/2214-4609.201401232.

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"Fingerprint database construction method based on optimized attenuation factor model." In 2017 2nd International Conference on Mechatronics and Information Technology. Francis Academic Press, 2017. http://dx.doi.org/10.25236/icmit.2017.40.

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Chen, Huaizhen, Junxiao Li, and Kristopher A. Innanen. "Inversion of seismic amplitudes for layer-weakness and attenuation factor." In First International Meeting for Applied Geoscience & Energy. Society of Exploration Geophysicists, 2021. http://dx.doi.org/10.1190/segam2021-3583367.1.

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Reports on the topic "Attenuation factor"

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VanDenberg, Carla. Mechanism of Growth Factor Attenuation of Cell Death in Chemotheraphy Treated Breast Cancer Cells. Fort Belvoir, VA: Defense Technical Information Center, August 2001. http://dx.doi.org/10.21236/ada400582.

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Van Den Berg, Carla. Mechanisms of Growth Factor Attenuation of Cell Death in Chemotherapy Treated Breast Cancer Cells. Fort Belvoir, VA: Defense Technical Information Center, August 2003. http://dx.doi.org/10.21236/ada424046.

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Van Den Berg, Carla. Mechanism of Growth Factor Attenuation of Cell Death in Chemotherapy Treated Breast Cancer Cells. Fort Belvoir, VA: Defense Technical Information Center, August 2000. http://dx.doi.org/10.21236/ada391062.

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Pete Lowry. Scoping Analysis of Source Term and Functional Containment Attenuation Factors. Office of Scientific and Technical Information (OSTI), October 2012. http://dx.doi.org/10.2172/1058087.

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Pete Lowry. Scoping Analysis of Source Term and Functional Containment Attenuation Factors. Office of Scientific and Technical Information (OSTI), February 2012. http://dx.doi.org/10.2172/1037782.

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Pete Lowry. Scoping Analysis of Source Term and Functional Containment Attenuation Factors. Office of Scientific and Technical Information (OSTI), January 2012. http://dx.doi.org/10.2172/1034817.

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Ron, Eliora, and Eugene Eugene Nester. Global functional genomics of plant cell transformation by agrobacterium. United States Department of Agriculture, March 2009. http://dx.doi.org/10.32747/2009.7695860.bard.

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The aim of this study was to carry out a global functional genomics analysis of plant cell transformation by Agrobacterium in order to define and characterize the physiology of Agrobacterium in the acidic environment of a wounded plant. We planed to study the proteome and transcriptome of Agrobacterium in response to a change in pH, from 7.2 to 5.5 and identify genes and circuits directly involved in this change. Bacteria-plant interactions involve a large number of global regulatory systems, which are essential for protection against new stressful conditions. The interaction of bacteria with their hosts has been previously studied by genetic-physiological methods. We wanted to make use of the new capabilities to study these interactions on a global scale, using transcription analysis (transcriptomics, microarrays) and proteomics (2D gel electrophoresis and mass spectrometry). The results provided extensive data on the functional genomics under conditions that partially mimic plant infection and – in addition - revealed some surprising and significant data. Thus, we identified the genes whose expression is modulated when Agrobacterium is grown under the acidic conditions found in the rhizosphere (pH 5.5), an essential environmental factor in Agrobacterium – plant interactions essential for induction of the virulence program by plant signal molecules. Among the 45 genes whose expression was significantly elevated, of special interest is the two-component chromosomally encoded system, ChvG/I which is involved in regulating acid inducible genes. A second exciting system under acid and ChvG/Icontrol is a secretion system for proteins, T6SS, encoded by 14 genes which appears to be important for Rhizobium leguminosarum nodule formation and nitrogen fixation and for virulence of Agrobacterium. The proteome analysis revealed that gamma aminobutyric acid (GABA), a metabolite secreted by wounded plants, induces the synthesis of an Agrobacterium lactonase which degrades the quorum sensing signal, N-acyl homoserine lactone (AHL), resulting in attenuation of virulence. In addition, through a transcriptomic analysis of Agrobacterium growing at the pH of the rhizosphere (pH=5.5), we demonstrated that salicylic acid (SA) a well-studied plant signal molecule important in plant defense, attenuates Agrobacterium virulence in two distinct ways - by down regulating the synthesis of the virulence (vir) genes required for the processing and transfer of the T-DNA and by inducing the same lactonase, which in turn degrades the AHL. Thus, GABA and SA with different molecular structures, induce the expression of these same genes. The identification of genes whose expression is modulated by conditions that mimic plant infection, as well as the identification of regulatory molecules that help control the early stages of infection, advance our understanding of this complex bacterial-plant interaction and has immediate potential applications to modify it. We expect that the data generated by our research will be used to develop novel strategies for the control of crown gall disease. Moreover, these results will also provide the basis for future biotechnological approaches that will use genetic manipulations to improve bacterial-plant interactions, leading to more efficient DNA transfer to recalcitrant plants and robust symbiosis. These advances will, in turn, contribute to plant protection by introducing genes for resistance against other bacteria, pests and environmental stress.

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Desiderati, Christopher. Carli Creek Regional Water Quality Project: Assessing Water Quality Improvement at an Urban Stormwater Constructed Wetland. Portland State University, 2022. http://dx.doi.org/10.15760/mem.78.

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Stormwater management is an ongoing challenge in the United States and the world at-large. As state and municipal agencies grapple with conflicting interests like encouraging land development, complying with permits to control stormwater discharges, “urban stream syndrome” effects, and charges to steward natural resources for the long-term, some agencies may turn to constructed wetlands (CWs) as aesthetically pleasing and functional natural analogs for attenuating pollution delivered by stormwater runoff to rivers and streams. Constructed wetlands retain pollutants via common physical, physicochemical, and biological principles such as settling, adsorption, or plant and algae uptake. The efficacy of constructed wetlands for pollutant attenuation varies depending on many factors such as flow rate, pollutant loading, maintenance practices, and design features. In 2018, the culmination of efforts by Clackamas Water Environment Services and others led to the opening of the Carli Creek Water Quality Project, a 15-acre constructed wetland adjacent to Carli Creek, a small, 3500-ft tributary of the Clackamas River in Clackamas County, OR. The combined creek and constructed wetland drain an industrialized, 438-acre, impervious catchment. The wetland consists of a linear series of a detention pond and three bioretention treatment cells, contributing a combined 1.8 acres of treatment area (a 1:243 ratio with the catchment) and 3.3 acre-feet of total runoff storage. In this study, raw pollutant concentrations in runoff were evaluated against International Stormwater BMP database benchmarks and Oregon Water Quality Criteria. Concentration and mass-based reductions were calculated for 10 specific pollutants and compared to daily precipitation totals from a nearby precipitation station. Mass-based reductions were generally higher for all pollutants, largely due to runoff volume reduction on the treatment terrace. Concentration-based reductions were highly variable, and suggested export of certain pollutants (e.g., ammonia), even when reporting on a mass-basis. Mass load reductions on the terrace for total dissolved solids, nitrate+nitrite, dissolved lead, and dissolved copper were 43.3 ± 10%, 41.9 ± 10%, 36.6 ± 13%, and 43.2 ± 16%, respectively. E. coli saw log-reductions ranging from -1.3 — 3.0 on the terrace, and -1.0 — 1.8 in the creek. Oregon Water Quality Criteria were consistently met at the two in-stream sites on Carli Creek for E. coli with one exception, and for dissolved cadmium, lead, zinc, and copper (with one exception for copper). However, dissolved total solids at the downstream Carli Creek site was above the Willamette River guidance value 100 mg/L roughly 71% of the time. The precipitation record during the study was useful for explaining certain pollutant reductions, as several mechanisms are driven by physical processes, however it was not definitive. The historic rain/snow/ice event in mid-February 2021 appeared to impact mass-based reductions for all metals. Qualitatively, precipitation seemed to have the largest effect on nutrient dynamics, specifically ammonia-nitrogen. Determining exact mechanisms of pollutant removals was outside the scope of this study. An improved flow record, more targeted storm sampling, or more comprehensive nutrient profiles could aid in answering important questions on dominant mechanisms of this new constructed wetland. This study is useful in establishing a framework and baseline for understanding this one-of-a-kind regional stormwater treatment project and pursuing further questions in the future.

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Brown Horowitz, Sigal, Eric L. Davis, and Axel Elling. Dissecting interactions between root-knot nematode effectors and lipid signaling involved in plant defense. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598167.bard.

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Root-knot nematodes, Meloidogynespp., are extremely destructive pathogens with a cosmopolitan distribution and a host range that affects most crops. Safety and environmental concerns related to the toxicity of nematicides along with a lack of natural resistance sources threaten most crops in Israel and the U.S. This emphasizes the need to identify genes and signal mechanisms that could provide novel nematode control tactics and resistance breeding targets. The sedentary root-knot nematode (RKN) Meloidogynespp. secrete effectors in a spatial and temporal manner to interfere with and mimic multiple physiological and morphological mechanisms, leading to modifications and reprogramming of the host cells' functions, resulted in construction and maintenance of nematodes' feeding sites. For successful parasitism, many effectors act as immunomodulators, aimed to manipulate and suppress immune defense signaling triggered upon nematode invasion. Plant development and defense rely mainly on hormone regulation. Herein, a metabolomic profiling of oxylipins and hormones composition of tomato roots were performed using LC-MS/MS, indicating a fluctuation in oxylipins profile in a compatible interaction. Moreover, further attention was given to uncover the implication of WRKYs transcription factors in regulating nematode development. In addition, in order to identify genes that might interact with the lipidomic defense pathway induced by oxylipins, a RNAseq was performed by exposing M. javanicasecond-stage juveniles to tomato protoplast, 9-HOT and 13-KOD oxylipins. This transcriptome generated a total of 4682 differentially expressed genes (DEGs). Being interested in effectors, we seek for DEGs carrying a predicted secretion signal peptide. Among the DEGs including signal peptide, several had homology with known effectors in other nematode species, other unknown potentially secreted proteins may have a role as root-knot nematodes' effectors which might interact with lipid signaling. The molecular interaction of LOX proteins with the Cyst nematode effectors illustrate the nematode strategy in manipulating plant lipid signals. The function of several other effectors in manipulating plant defense signals, as well as lipids signals, weakening cell walls, attenuating feeding site function and development are still being studied in depth for several novel effectors. As direct outcome of this project, the accumulating findings will be utilized to improve our understanding of the mechanisms governing critical life-cycle phases of the parasitic M. incognita RKN, thereby facilitating design of effective controls based on perturbation of nematode behavior—without producing harmful side effects. The knowledge from this study will promote genome editing strategies aimed at developing nematode resistance in tomato and other nematode-susceptible crop species in Israel and the United States.

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Gamma ray self attenuation correction factor study. Final report. Office of Scientific and Technical Information (OSTI), April 1993. http://dx.doi.org/10.2172/378898.

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