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Littérature scientifique sur le sujet « Null Reactions »

Auteur : Grafiati

Publié le 29 mars 2025

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Articles de revues sur le sujet "Null Reactions"

Zhang-Liu, Yiran, Rolf Müller, Jens-Uwe Grooß, Sabine Robrecht, Bärbel Vogel, Abdul Mannan Zafar et Ralph Lehmann. « The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring ». Atmospheric Chemistry and Physics 24, n^o 22 (14 novembre 2024) : 12557–74. http://dx.doi.org/10.5194/acp-24-12557-2024.

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Abstract. Simulations of Antarctic chlorine and ozone chemistry in previous work show that in the core of the Antarctic vortex (16–18 km, 85–55 hPa, 390–430 K) HCl null cycles (initiated by reactions of Cl with CH4 and CH2O) are effective. These HCl null cycles cause both HCl molar mixing ratios to remain very low throughout Antarctic winter and spring. They cause ozone-destroying chlorine (ClOx) to remain enhanced so that rapid ozone depletion proceeds. Here we investigate the impact of the observed dehydration in Antarctica, which strongly reduces ice formation and the uptake of HNO3 from the gas phase; however the efficacy of HCl null cycles is not affected. Moreover, also when using the observed very low HCl molar mixing ratios in Antarctic winter as an initial value, HCl null cycles are efficient in maintaining low HCl (and high ClOx) throughout winter and spring. Further, the reaction CH3O2+ClO is important for the efficacy of the HCl null cycle initiated by the reaction CH4+Cl. Using the current kinetic recommendations instead of earlier ones has very little impact on the simulations. All simulations presented here for the core of the Antarctic vortex show extremely low minimum ozone values (below 50 ppb) in late September to early October in agreement with observations.

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Rezaee, Zabihollah, Phil Malone et Ghassem Homaifar. « An Assessment Of Event Study Methodologies Using Daily Stock Returns ». Journal of Applied Business Research (JABR) 8, n^o 1 (18 octobre 2011) : 78. http://dx.doi.org/10.19030/jabr.v8i1.6186.

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This paper examines Multinational Stock Price reactions to foreign currency translation, using three alternative residual methodologies. The results reveal that when a crude measure such as Mean Adjusted Return, which makes not explicit risk adjustments is used, the null hypothesis of zero abnormal return is rejected in three out of six events. However, market and risk adjusted residual returns reveal that the null hypothesis of zero abnormal return cannot be rejected.

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Klčová, Lenka, Daniela Mikulíková, Štefan Masár et Alžbeta Žofajová. « Evaluation Of Slovak Winter Wheat Quality In Terms Of Puroindoline Genes ». Agriculture (Polnohospodárstvo) 61, n^o 3 (1 septembre 2015) : 88–96. http://dx.doi.org/10.1515/agri-2015-0014.

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Abstract The grain hardness of 100 current and 24 old superior Slovak winter wheat cultivars was studied at molecular level. Using polymerase chain reactions (PCRs), normal and null alleles of both puroindoline Pina and Pinb genes were identified. Three different genotypes were found: 1) normal allele of both genes (dominant wild type with soft endosperm) − Pina-D1a/Pinb-D1a; 2) normal allele of the Pina gene and null allele of the Pinb gene – Pina-D1a/Pinb-D1b; and 3) null allele of the Pina gene and normal allele of the Pinb gene Pina-D1b/Pinb-D1a. No Slovak current as well as old wheat cultivar had together null allele of both puroindoline genes. The frequencies of wild-type Pinb-D1a and null Pinb-D1b allele in current cultivars were 62.0% and 38.0%, respectively, whilst in old cultivars, 8.3% and 91.7%, respectively. Regarding null allele Pina-D1b of puroindoline Pina gene, only in Rheia current cultivar, one was found. All other cultivars had wild-type Pina-D1a allele. Alacris, Alana, Axis, Balada, Blava, Bona Dea, Bruta, Charger, Hana, Ilona, IS Karpatia, Ludwig and Sulamit current cultivars were selected as donors of the null Pinb-D1b allele for molecular breeding in order to improve the grain hardness as important wheat quality trait. Statistically significant correlations between null Pinb-D1b allele and grain size as well as colour were found. In comparison with wild type, cultivars with this null allele have paler and longer grain with higher length-to-width ratio and lighter grain colour.

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Stenger, Drake C., Roy French et Frederick E. Gildow. « Complete Deletion of Wheat Streak Mosaic Virus HC-Pro : a Null Mutant Is Viable for Systemic Infection ». Journal of Virology 79, n^o 18 (15 septembre 2005) : 12077–80. http://dx.doi.org/10.1128/jvi.79.18.12077-12080.2005.

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ABSTRACT A Wheat streak mosaic virus (WSMV) genome lacking HC-Pro was constructed and confirmed by reverse transcription-PCR to systemically infect wheat, oat, and corn. Coupled in vitro transcription/translation reactions indicated that WSMV P1 proteinase cleaved the polyprotein at the P1/P3 junction of the HC-Pro null mutant. The WSMV HC-Pro null mutant was competent for virion formation, but the virus titer was reduced 4.5-fold relative to that of the wild type. Collectively, these results indicate that WSMV HC-Pro is dispensable for replication and movement, two essential processes that are disrupted by point and small-insertion mutations introduced into potyvirus HC-Pro.

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Moore, Angus K., et Darryl E. Granger. « Technical note : Altitude scaling of ³⁶Cl production from Fe ». Geochronology 6, n^o 4 (18 octobre 2024) : 541–52. http://dx.doi.org/10.5194/gchron-6-541-2024.

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Abstract. Cosmogenic nuclide production rates depend on the excitation functions of the underlying nuclear reactions and the intensity and energy spectrum of the cosmic-ray flux. The cosmic-ray energy spectrum shifts towards lower average energies with decreasing altitude (increasing atmospheric depth), so production rate scaling will differ for production reactions that have different energy sensitivities. Here, we assess the possibility of the unique scaling of 36Cl production from Fe by modeling changes in the 36ClFe/36ClK and 36ClFe/10Beqtz production ratios with altitude. We evaluate model predictions against measured 36Cl concentrations in magnetite and K-feldspar and 10Be concentrations in quartz from granitic rocks exposed across an elevation transect (ca. 1700–4300 ma.s.l.) in western North America. The data are broadly consistent with model predictions. The null hypothesis that 36ClFe/10Beqtz and 36ClFe/36ClK production ratios are invariant with altitude can be rejected at the 90 % confidence level. Thus, reaction-specific scaling factors will likely yield more accurate results than non-reaction-specific scaling factors when scaling 36Cl production in Fe-rich rocks and minerals.

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Kim, Sang-Heon, Sang-Hoon Kim, Ho Joo Yoon, Dong Ho Shin, Sung Soo Park, Youn-Seup Kim, Jae-Seuk Park et Young Koo Jee. « GSTT1 and GSTM1 null mutations and adverse reactions induced by antituberculosis drugs in Koreans ». Tuberculosis 90, n^o 1 (janvier 2010) : 39–43. http://dx.doi.org/10.1016/j.tube.2009.12.001.

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Doming, Luis R., et Mar Ríos-Gutiérrez. « A Useful Classification of Organic Reactions Based on the Flux of the Electron Density ». Scientiae Radices 2, n^o 1 (14 février 2023) : 1–24. http://dx.doi.org/10.58332/scirad2023v2i1a01.

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A useful classification of polar organic reactions in Forward Electron Density Flux (FEDF) and Reverse Electron Density Flux (REDF), based on the unambiguously analysis of the direction of the flux of the global electron density transfer (GEDT) at the transition state structures (TSs), has been recently proposed (RSC Adv. 2020, 10, 15394) within the Molecular Electron Density Theory. Further, non-polar reactions have been classified as Null Electron Density Flux (NEDF) (Eur. J. Org. Chem. 2020, 5938). This classification allows characterizing the nucleophilic/electrophilic species participating in polar reactions. Analysis of the electronic chemical potential m, and the electrophilicity w and nucleophilicity N indices, defined within Conceptual DFT, at the ground state (GS) of the reagents also permits to establish this classification of polar reactions.

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Economopoulos, Konstantinos P., Theodoros N. Sergentanis et Nikos F. Vlahos. « Glutathione S-transferase M1, T1, and P1 Polymorphisms and Ovarian Cancer Risk : A Meta-Analysis ». International Journal of Gynecologic Cancer 20, n^o 5 (juin 2010) : 732–37. http://dx.doi.org/10.1111/igc.0b013e3181dedeb5.

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Introduction:Cytosolic glutathione S-transferase (GST) comprises multiple isoenzymes that catalyze reactions between glutathione and lipophilic compounds with electrophilic centers, resulting in the neutralization of toxic compounds, xenobiotics, and products of oxidative stress. Several studies have examined whether GST polymorphisms (GSTM1 null/present genotype, GSTT1 null/present genotype, and GSTP1 Ile105Val) represent risk factors for ovarian cancer, as they all may denote reduced enzyme activity. This meta-analysis aimed to examine the associations between the aforementioned polymorphisms and ovarian cancer risk.Methods:The MEDLINE database was searched up to September 2009 using the appropriate terms. Case-control studies with no mutually overlapping populations were selected. Pooled odds ratios (ORs) were appropriately derived from fixed-effects or random-effects models. Meta-regression with publication year was also performed.Results:Eight studies regarding GSTM1 null polymorphism status (2357 cases and 3044 controls), 6 studies concerning GSTT1 null polymorphism (1923 cases and 2759 controls), and 3 studies on GSTP1 Ile105Val were included in the meta-analysis. The GSTM1 null genotype was not associated with an increased risk for ovarian cancer (pooled OR, 1.031; 95% confidence interval, 0.867-1.226; random effects). The GSTT1 null genotype was not associated with an increased ovarian cancer risk (pooled OR, 0.934; 95% confidence interval, 0.804-1.086; random effects); similarly, no significant associations were demonstrated for GSTP1 Ile105Val.Conclusions:The examined GSTM1, GSTT1, and GSTP1 genotype polymorphisms do not seem to confer any additional risk for ovarian cancer. Given that the studies included in this meta-analysis involve mainly white populations, these results cannot be extrapolated on other populations, and additional data are needed for future race-specific analyses.

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Zhang, Weifeng, Xueling Chen, Xingxing Chen, Jirui Li, Hui Wang, Xiaomiao Yan, Han Zha et al. « Fc–Fc interactions and immune inhibitory effects of IgG4 : implications for anti-PD-1 immunotherapies ». Journal for ImmunoTherapy of Cancer 12, n^o 6 (juin 2024) : e009034. http://dx.doi.org/10.1136/jitc-2024-009034.

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BackgroundThe majority of anti-programmed cell-death 1 (PD-1) monoclonal antibodies (mAbs) use S228P mutation IgG4 as the structural basis to avoid the activation of immune cells or complement. However, little attention has been paid to the Fc–Fc interactions between IgG4 and other IgG Fc fragments that could result in adverse effects. Fc-null IgG1 framework is a potential safer alternative to avoid the undesirable Fc–Fc interactions and Fc receptor binding derived effects observed with IgG4. This study provides a comprehensive evaluation of anti-PD-1 mAbs of these two frameworks.MethodsTrastuzumab and rituximab (both IgG1), wildtype IgG1 and IgG4 were immobilized on nitrocellulose membranes, coated to microplates and biosensor chips, and bound to tumor cells as targets for Fc–Fc interactions. Wildtype IgG1 and IgG4, anti-PD-1 mAb nivolumab (IgG4 S228P), penpulimab (Fc-null IgG1), and tislelizumab (Fc-null IgG4 S228P-R409K) were assessed for their binding reactions to the immobilized IgG proteins and quantitative kinetic data were obtained. To evaluate the effects of the two anti-PD-1 mAbs on immune responses mediated by trastuzumab and rituximab in the context of combination therapy, we employed classic immune models for antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement dependent cytotoxicity. Tumor-bearing mouse models, both wildtype and humanized, were used for in vivo investigation. Furthermore, we also examined the effects of IgG1 and IgG4 on diverse immune cell populationsResultsExperiments demonstrated that wildtype IgG4 and nivolumab bound to immobilized IgG through Fc–Fc interactions, diminishing antibody-dependent cell-mediated cytotoxicity and phagocytosis reactions. Quantitative analysis of kinetic parameters suggests that nivolumab and wildtype IgG4 exhibit comparable binding affinities to immobilized IgG1 in both non-denatured and denatured states. IgG4 exerted inhibitory effects on various immune cell types. Wildtype IgG4 and nivolumab both promoted tumor growth in wildtype mouse models. Conversely, wildtype IgG1, penpulimab, and tislelizumab did not show similar adverse effects.ConclusionsFc-null IgG1 represents a safer choice for anti-PD-1 immunotherapies by avoiding both the adverse Fc–Fc interactions and Fc-related immune inhibitory effects of IgG4. Fc-null IgG4 S228P-R409K and Fc-null IgG1 displayed similar structural properties and benefits. This study contributes to the understanding of immunotherapy resistance and the advancement of safer immune therapies for cancer.

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Jaramillo-Valverde, Luis, Kelly S. Levano, David D. Tarazona, Andres Vasquez-Dominguez, Anel Toledo-Nauto, Silvia Capristano, Cesar Sanchez, Eduardo Tarazona-Santos, Cesar Ugarte-Gil et Heinner Guio. « GSTT1/GSTM1 Genotype and Anti-Tuberculosis Drug-Induced Hepatotoxicity in Peruvian Patients ». International Journal of Molecular Sciences 23, n^o 19 (20 septembre 2022) : 11028. http://dx.doi.org/10.3390/ijms231911028.

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In Peru, 24,581 people were diagnosed with tuberculosis (TB) in 2020. Although TB treatments are effective, 3.4–13% are associated with significant adverse drug reactions (ADRs), with drug-induced liver injury (DILI) considered the most predominant. Among the first-line antituberculosis drugs, isoniazid (INH) is the main drug responsible for the appearance of DILI. In the liver, INH is metabolized by the enzymes N-acetyltransferase-2 (NAT2), cytochrome P450 2E1 (CYP2E1), and glutathione S-transferase (GST) with two isoforms, GSTT1 and GSTM1. Based on previous studies, we hypothesized that interactions between the GSTT1 and GSTM1 null genotypes induce DILI in TB patients. In this cross-sectional study of 377 participants who completed their anti-TB treatment, we genotyped by revealing the presence or absence of 215- and 480-bp bands of GSTM1 and GSTT1, respectively. We found that the prevalence of the GSTM1 genotype was 52.79% and 47.21% for presence and null, respectively, and for GSTT1 it was 69.76% and 30.24% for presence and null, respectively. Neither genotype was prevalent in the patients who developed DILI (n = 16). We did not confirm our hypothesis; however, we found that the combination of GSTM1 present genotype, GSTT1 null genotype, fast NAT2 acetylators, and CYP2E1 c1/c1 genotype had a significant risk for the development of ADR (OR 11; p = 0.017; 95% CI: (0.54–186.35)). We propose that the presence of the GSTM1 present genotype, GSTT1 null genotype, fast NAT2 acetylators, and CYP2E1 c1/c1 genotype in the Peruvian population could be considered a risk factor for the development of ADR due to therapeutic drug intake.

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Thèses sur le sujet "Null Reactions"

Zheng, Lianqing. « Statistical identification of metabolic reactions catalyzed by gene products of unknown function ». Diss., Kansas State University, 2013. http://hdl.handle.net/2097/15594.

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Doctor of Philosophy
Department of Statistics
Gary L. Gadbury
High-throughput metabolite analysis is an approach used by biologists seeking to identify the functions of genes. A mutation in a gene encoding an enzyme is expected to alter the level of the metabolites which serve as the enzyme’s reactant(s) (also known as substrate) and product(s). To find the function of a mutated gene, metabolite data from a wild-type organism and a mutant are compared and candidate reactants and products are identified. The screening principle is that the concentration of reactants will be higher and the concentration of products will be lower in the mutant than in wild type. This is because the mutation reduces the reaction between the reactant and the product in the mutant organism. Based upon this principle, we suggest a method to screen the possible lipid reactant and product pairs related to a mutation affecting an unknown reaction. Some numerical facts are given for the treatment means for the lipid pairs in each treatment group, and relations between the means are found for the paired lipids. A set of statistics from the relations between the means of the lipid pairs is derived. Reactant and product lipid pairs associated with specific mutations are used to assess the results. We have explored four methods using the test statistics to obtain a list of potential reactant-product pairs affected by the mutation. The first method uses the parametric bootstrap to obtain an empirical null distribution of the test statistic and a technique to identify a family of distributions and corresponding parameter estimates for modeling the null distribution. The second method uses a mixture of normal distributions to model the empirical bootstrap null. The third method uses a normal mixture model with multiple components to model the entire distribution of test statistics from all pairs of lipids. The argument is made that, for some cases, one of the model components is that for lipid pairs affected by the mutation while the other components model the null distribution. The fourth method uses a two-way ANOVA model with an interaction term to find the relations between the mean concentrations and the role of a lipid as a reactant or product in a specific lipid pair. The goal of all methods is to identify a list of findings by false discovery techniques. Finally a simulation technique is proposed to evaluate properties of statistical methods for identifying candidate reactant-product pairs.

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Sahim, Abderrahim. « Nouvelle approche basée sur Monte Carlo pour la modélisation des systèmes chimiquement réactifs : application à la pyrolyse de la biomasse lignocellulosique ». Electronic Thesis or Diss., Université de Toulouse (2023-....), 2025. http://www.theses.fr/2025TLSEP008.

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Une nouvelle approche stochastique basée sur le "Monte Carlo Formulation Intégrale" est présentée dans cette thèse pour modéliser la cinétique de dégradation de la biomasse lignocellulosique au cours de la pyrolyse. La pyrolyse, définie comme la dégradation thermique de la biomasse en absence de dioxygène, est un processus complexe impliquant des réactions primaires et secondaires influencées par les transferts de chaleur et de matière, avec des propriétés physiques de la biomasse qui varient en fonction de sa composition chimique. Cette complexité est accentuée par le couplage de divers phénomènes physiques et réactions chimiques. Pour y faire face, des méthodes statistiques de Monte Carlo sont adoptées, étant insensibles à la complexité des domaines d'intégration, ce qui les rend particulièrement adaptées à la simulation de tel procédé. Dans le premier cas d’étude, le couplage cinétique/cinétique en conditions isothermes a été exploré, en modélisant des réactions chimiques (en parallèle, successives et/ou réversibles) de premier ordre couplées. Le modèle cinétique a été formulé sous forme d'un système d’espérances couplées, et ce couplage a été traité à l'aide de la méthode de double randomisation. Des scénarios de raideur ont également été abordés en étant traités à l'aide d'un échantillonnage par importance, guidé par des approximations classiques telles que l'équilibre partiel et l'approximation des états quasi-stationnaires, permettant ainsi d'obtenir des résultats similaires aux solutions analytiques, tout en étendant la méthode à des schémas réactionnels plus complexes. Dans le deuxième cas d'étude, des conditions non-isothermes sont considérées. Il est supposé que la température et les constantes de vitesses sont connues et prescrites. Pour modéliser ce couplage entre la dynamique thermique et la cinétique, des algorithmes à réactions nulles sont introduits. Cette approche a été appliquée au modèle de Broido-Shafizadeh pour la pyrolyse de la cellulose, montrant qu'un algorithme à réactions nulles sans rejet est optimal pour les réactions simples, tandis qu'un algorithme avec rejet s'avère plus performant pour des schémas réactionnels avec des réactions couplées. Enfin, dans le troisième cas d’étude, cette approche a été étendue pour traiter le couplage thermique/cinétique non-linéaire avec un modèle thermique non-prescrit, formulé sous forme d'espérance. Ce cas présente un défi particulier en raison de la non-linéarité de la loi de couplage (loi d'Arrhenius). Une méthode permettant de contourner cette non-linéarité en utilisant les collisions nulles est proposée, et il est démontré que cette approche fournit des résultats comparables à ceux des solutions déterministes dans des cas simples. Cependant, elle nécessite encore des améliorations pour des scénarios plus complexes, en raison des coûts de calcul élevés et de la lenteur de convergence. La modélisation multi-échelle et multiphysique de la pyrolyse est contribué par cette thèse en abordant les principaux défis associés au couplage thermique/cinétique et à la non-linéarité. Des perspectives pour des recherches futures visant à améliorer ces méthodes pour des systèmes plus complexes sont également ouvertes
A new stochastic approach based on the "Monte Carlo Integral Formulation" is presented in this thesis to model the degradation kinetics of lignocellulosic biomass during pyrolysis. Pyrolysis, defined as the thermal degradation of biomass in the absence of dioxygen, is a complex process involving primary and secondary reactions influenced by heat and mass transfer, with physical properties of the biomass varying according to its chemical composition. This complexity is accentuated by the coupling of various physical phenomena and chemical reactions. To address this, Monte Carlo statistical methods are adopted, as they are insensitive to the complexity of the integration domains, making them particularly well-suited for the simulation of such processes. In the first case study, the kinetic/kinetic coupling under isothermal conditions was explored, modeling first-order coupled chemical reactions (in parallel, successive, and/or reversible). The kinetic model was formulated as a system of coupled expectations, and this coupling was addressed using the double randomization method. Stiffness scenarios were also tackled by using importance sampling, guided by classical approximations such as partial equilibrium and quasi-stationary state approximations, allowing results similar to analytical solutions to be obtained while extending the method to more complex reaction schemes. In the second case study, non-isothermal conditions are considered. It is assumed that the temperature and rate constants are known and prescribed. To model the coupling between thermal dynamics and kinetics, null-reaction algorithms are introduced. This approach was applied to the Broido-Shafizadeh model for cellulose pyrolysis, showing that a null-reaction algorithm without rejection is optimal for simple reactions, while an algorithm with rejection is found to perform better for reaction schemes with coupled reactions. Finally, in the third case study, this approach was extended to handle nonlinear thermal/kinetic coupling with a non-prescribed thermal model, formulated as an expectation. This case presents a particular challenge due to the non-linearity of the coupling law (Arrhenius law). A method to bypass this non-linearity using null collisions is proposed, and it is shown that this approach provides results comparable to deterministic solutions in simple cases. However, improvements are still required for more complex scenarios due to high computational costs and slow convergence. This thesis contributes to the multi-scale and multiphysics modeling of pyrolysis by addressing the main challenges associated with thermal/kinetic coupling and non-linearity. It also opens up perspectives for future research aimed at improving these methods for more complex systems

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Mahfoudhi, Imed. « Problèmes inverses de sources dans des équations de transport à coefficients variables ». Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00975168.

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Cette thèse porte sur l'étude de quelques questions liées à l'identifiabilité et l'identification d'un problème inverse non-linéaire de source. Il s'agit de l'identification d'une source ponctuelle dépendante du temps constituant le second membre d'une équation de type advection-dispersion-réaction à coefficients variables. Dans le cas monodimensionnel, la souplesse du modèle stationnaire nous a permis de développer des réponses théoriques concernant le nombre des capteurs nécessaires et leurs emplacements permettant d'identifier la source recherchée d'une façon unique. Ces résultats nous ont beaucoup aidés à définir la ligne de conduite à suivre afin d'apporter des réponses similaires pour le modèle transitoire. Quant au modèle bidimensionnel transitoire, en utilisant quelques résultats de nulle contrôlabilité frontière et des mesures de l'état sur la frontière sortie et de son flux sur la frontière entrée du domaine étudié, nous avons établi un théorème d'identifiabilité et une méthode d'identification permettant de localiser les deux coordonnées de la position de la source recherchée comme étant l'unique solution d'un système non-linéaire de deux équations, et de transformer l'identification de sa fonction de débit en la résolution d'un problème de déconvolution. La dernière partie de cette thèse discute la difficulté principale rencontrée dans ce genre de problèmes inverses à savoir la non identifiabilité d'une source dans sa forme abstraite, propose une alternative permettant de surmonter cette difficulté dans le cas particulier où le but est d'identifier le temps limite à partir duquel la source impliquée a cessé d'émettre, et donc ouvre la porte sur de nouveaux horizons.

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Božek, Michal. « Kondenzační parní turbína K55 ». Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417525.

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The main aim of this diploma thesis is design and calculation of steam condensing turbine with given parameters. In the first part is made calculation of heat balance scheme, which contains high and low pressure regeneration and turbine with total of 5 unregulated steam extraction. It is followed by calculation of regulating stage with impulse blading and calculation of stage part of turbine with reaction blades with total of 27 stages divided to 7 cones. Designes of regulating stage and stage part were checked by calculation of tensile and bending stress. In next parts are calculations of compensating piston and turbine seal system, design of radial and thrust bearings and in the last chapter is shown consumption characteristics of turbine. The designed turbine after optimization at nominal condition has power of 55013,02 kW with thermodynamic efficiency of 83,06 %. The reheat factor of turbine is 1,063. The diploma thesis is supplemented by a conceptual sectional drawing of turbine.

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Brezová, Gabriela. « Analýza způsobu reakce řidiče na náhlý podnět ». Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-446748.

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The diploma thesis deal with what ways drivers react to an unexpected stimulus. In the theoretical part, the analysis of the current state, reaction time, methods of reaction of the driver, stimuli from the environment and finally is being analyzed, the vehicle and its assistance systems. The analytical part of the diploma thesis was performed by driving tests, where it was found that the way the driver reacts from the distance to which they are obstructed and the speed of the vehicle. For that reason, a TTC dependency analysis was performed. It was found that drivers at low TTC values chose an obstacle in which they brake the need to move their foot from the accelerator pedal to the brake pedal and they have to brake sharply. At medium TTC values, drivers brake most often. In the case of a combination of conductors, they chose braking with avoiding at lower TTC values and avoiding with braking at medium TTC values. There was also a dependence of the method of reaction on driving experience. Inexperienced drivers rather choose braking, experienced drivers use combinations.

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Boldovjaková, Tatiana. « Post-polymerační modifikace polyolefinů pro přípravu hydroxylovaných makroiniciátorů ». Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-432943.

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The diploma thesis deals with post-polymerization hydroxylation of polypropylene in solid state. Regarding the literature review, polypropylene was hydroxylated by radical grafting in aqueous solution of potassium persulfate at 100 °C, under nitrogen atmosphere for 60 minutes. Hydroxylation of polypropylene was performed at different concentrations of potassium persulfate (1; 5; 10 mol. %) and two different water/potassium persulfate molar ratios. The effects of reaction system composition and reaction conditions on reaction efficiency, extent of side reactions, thermal and rheological properties of hydroxylated polypropylene were evaluated. The presence and concentration of hydroxyl groups on polypropylene surface was determined by structural analysis (FTIR, XPS), while the highest efficiency was achieved in the presence of nonionic wetting agents, using 10 mol. % potassium persulfate and at lower water/potassium persulfate molar ratio. Based on changes in polypropylene structure, the modification took place mainly in the amorphous phase of the polymer. In addition to hydroxylation, concurrent side reactions have been reported, in particular the oxidation of wetting agents and polypropylene, which has resulted in chain cleavage, reducing the average molecular weight of the polypropylene.

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Bucsuházy, Kateřina. « Analýza reakční doby dětí ». Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234437.

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This diploma thesis deals with children‘s reaction time. The theoretical part of this work describes children as vulnerable road users and discusses methods of measuring reaction time. The practical part presents some realized experiments refer to the children’s reaction time and their results evaluation.

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Černo, Lukáš. « Localizing reactions to globalization among Czech beer consumers and their relation to the phenomenon of identity crisis ». Master's thesis, Vysoká škola ekonomická v Praze, 2011. http://www.nusl.cz/ntk/nusl-124546.

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The goal of this thesis is to define what globalization is, how the people across the world react to it based on their local context, how the reactions change under the conditions of economic crises and finally how the reactions are reflected in consumption. I answer these goals both from the theoretical and practical perspective. Based on my review of theory I define globalization (1) in economic terms as a recurring phenomenon related to changing power structures of world economy when new economic centers emerge and (2) in cultural terms as localized human experience determined by both one's worldview and one's local circumstances. I further hypothesize that the worldview underlying this localized experience changes during economic crises from modernism to traditionalism and postmodernism. Since Consumption then reflects our worldview in a culturally specific way. In the practical part I further test these findings through a netnographic study focused on Czech beer enthusiasts. The key finding is that the beer enthusiasts express a need to return to traditional brewing methods. However, there appears to be no correlation between economic crisis and the emergence of traditionalism among beer enthusiasts but rather the traditionalism erupst due to clash between modernist worldview of beer enthusiasts and perceived destruction of beer industry by capitalism. Finally, the traditionalism doesn't seem to be replacing modernist worldview of beer enthusiasts but rather serves as a resource for this worldview.

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Dolejský, Lukáš. « Analýza vnitřního hluku vozidel a jeho vliv na aktivní bezpečnost ». Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-232763.

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Thesis is focused on the impact of the inside noise of the car on conditional driver safety, which is presented by reaction times on simulated stimulus. In introduction, there is a theoretical definition of the security of the vehicles, inside noise, and its methods of measurement. Practical part consists of description and realization of the measurements of the impact on the inside noise in the car on reaction time of drivers. Conclusion includes evaluations of the measurements and findings, which results from them.

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Becová, Lucia. « Měření parametrů lidského operátora ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400558.

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This work focuses on evaluating the parameters of the human operator as the driver of the vehicle simulator. In the first part, the thesis focuses on the examination of human operator parameters evaluation. In the second part of the thesis is a proposal of various scenarios focused on a specific area of measurement. At the end, the work focuses on the processing and evaluation of measured data obtained from the drivers tested.

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Chapitres de livres sur le sujet "Null Reactions"

Weiss, Avishai, Frederick Leve, Ilya V. Kolmanovsky et Moriba Jah. « Reaction Wheel Parameter Identification and Control through Receding Horizon-Based Null Motion Excitation ». Dans Advances in Estimation, Navigation, and Spacecraft Control, 477–94. Berlin, Heidelberg : Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44785-7_25.

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« Null Collision Monte Carlo Method : Gas Mixtures with Internal Degrees of Freedom and Chemical Reactions ». Dans Rarefied Gas Dynamics : Physical Phenomena, 25–39. Washington DC : American Institute of Aeronautics and Astronautics, 1989. http://dx.doi.org/10.2514/5.9781600865916.0025.0039.

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Tinker, Peter B., et Peter Nye. « Solute Interchange between Solid, Liquid, and Gas Phases in the Soil ». Dans Solute Movement in the Rhizosphere. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195124927.003.0007.

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We noted in chapter 1 that the concentration of solute in the soil solution is buffered by solute adsorbed on the soil surfaces. We also show in chapter 4 that the overall mobility of ions is related to their amounts and mobilities in the solid and solution. In this chapter, we focus on the soil solution concentration, primarily to show how the factors controlling it can be incorporated in models of the growth of crops and the leaching of nutrients or pollutants, such as those described in chapters 10 and 11. We examine the general principles governing the interchange of solutes between all phases in the soil, dealing first with inorganic ions, especially plant nutrients and heavy metals; and later with organic solutes, including biocides, which may also occur in the vapour phase. We also consider the reactions between metal ions and other organic or inorganic ions in solution to form complexes, such as CuOH+. The method of displacing the pore solution from a column of soil with ethanol, introduced by Ischtscherikow (1907), has been examined by Moss (1963, 1969). He found, in accord with theory (section 3.1.3), that the activity ratios (K)/(Ca + Mg)1/2 and (K)/(Ca)1/2 determined in the displaced solutions remained constant over considerable changes in soil moisture level to the point of saturation. He also found that the activity ratio (K)/(Ca + Mg)1/2 in the extracts from a wide range of soils agreed well with the activity ratio determined by the null point method of Beckett & Craig (1964). In this method, the soil is shaken with dilute CaCl2 solution containing graded amounts of potassium, and the activity ratio at which the soil does not gain or lose potassium to the solution is determined. Ethanol appears to displace solution from the fine as well as the coarse pores, and successive fractions, devoid of alcohol, have the same composition. For small samples of soil, it is more convenient to add a heavy liquid that is immiscible with water, and extract the solution by centrifuging (Kinniburgh & Miles 1983). Suction methods are useful for following changes in composition of moist soils. They should be used with care since they change the pressure of CO2 and hence the concentration of the bicarbonate ion.

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Dinh Van Phong et Nguyen Hai Nguyen. « A new approach of using null space of Jacobian matrix in simulation of multibody dynamics ». Dans Studies in Applied Electromagnetics and Mechanics. IOS Press, 2012. https://doi.org/10.3233/978-1-61499-092-5-44.

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Simulation of multibody systems is associated with deriving equations of motion and finding numerical solution of the equation. The combination of the differential equations and constraints yields index-3 differential-algebraic equations (DAE's) that are not, in general, easily solvable by standard integration schemes. Moreover at singular configurations, some methods can fail. This paper focuses on the discussion of two problems: determining the singular configurations and their neighborhood and overcoming the singularity smoothly. Overcoming the singularity is discussed with using the Principle of Compatibility, so far not well-known. In this principle the equations of motion are rewritten in the form which can be solved by numerical techniques smoothly, even over singular configurations without detector. The idea of this approach is introducing so-called generalized reaction forces which appear in the equations of motion system for the dynamical in comparison with the system without constraints. The formulation is proven to be more stable and accurate under repetitive meeting singular configurations. These generalized reaction forces can be determined by using the ideality condition of constraints which employs the null space of constraints imposed to the system. Some numerical experiments are carried out to verify the efficiency and speed of the approach.

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« The principle of the MAIEA technique depends on the binding of two antibodies made in different species to different determinants on the same membrane component to form of a tri-molecular complex [4]. Briefly, a murine monoclonal antibody (MAb) and human antibody are incubated simultaneously with red cells. Excess antibody is removed, the sensitized cells are solubilised with Triton, so the tri-molecular complex is released into solution. The complex is detected by an ELISA type assay. The tri-molecular complex is captured by an anti-mouse globulin precoated onto a microtitre plate. The human antibody is then detected by a peroxidase-conjugated anti-human IgG. A positive reaction gives a high absorbance value and a negative reaction gives a low absorbance value. A negative result is obtained when the antibodies used bind to different membrane components, so no tri-molecular complex is formed. A negative result is also obtained when the monoclonal antibody and human antibody compete for the same epitope. Results can be represented as ratios of absorbances for antigen positive to antigen negative cells or as bar charts. In these studies a murine anti-CR1 (E11) and human anti-Kna and other Knops system antibodies were used against antigen positive and antigen negative cells. Absorbances for antigen positive cells with anti-Kna, anti-McCa anti-Sla and anti-Yka were high and results for the antigen-negative cells were low [8]. Comparison of chymotrypsin treated Kn(a+) cells with Kn(a-) cells showed that chymotrypsin did indeed destroy Kna antigen ; chymotrypsin treated cells, therefore, were suitable cells to use as antigen negative cells when cells of rare phenotype were not available [8]. These reactions gave significantly positive ratios (Table I). In contrast, low absorbances were recorded for Cs(a+) and Cs(a-) cells with anti-Csa, the 1:1 ratio indicating a negative result (Table I). Serologically the Helgeson phenotype cells have a Knops null phenotype, all 4 antigens are negative but the antigens could be detected by flow cytometry and in immune precipitation [6,7]. Moulds and colleagues provided an explanation for this when they found that such cells did not completely lack CR1 but had a low copy number of CR1 molecules per cell [9]. Had it not been known already, the presence of Knops system antigens on Helgeson phenotype cells could have been deduced from the MAIEA results. The absorbance values for Helgeson phenotype cells were significantly higher than for antigen negative cells for Kna, McCa and Yka [8]. MAIEA has confirmed that Kna, McCa, Sla and Yka but not Csa are associated with the CR1 molecule in the red cell membrane and can detect weak expression of CR1 antigens on Helgeson phenotype cells [8]. MAIEA is useful for investigating problem antibodies suspected to be Knops system antibodies and can also be used to Knops phenotype cells with poor expression of Knops system antigens. » Dans Transfusion Immunology and Medicine, 189. CRC Press, 1995. http://dx.doi.org/10.1201/9781482273441-8.

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« roles of carrier proteins. The identification and usefulness of blood group antigens as markers will be described and possible explanations for their variation in expression will be discussed. Most red cell antigens have been investigated because they are clinically important [1]. The antibodies to some antigens have caused haemolytic disease of the newborn and/or transfusion reactions. Other antigens are involved in haemolytic anaemia and some are important in transplantation. Red cell antigens provided a tool for investigation of the red cell surface and for use as genetic, immunological and biochemical markers. More than 500 red cell antigens are serologically defined, about half of which have been officially recognised and have been numbered by the International Society of Blood Transfusion Working Party on Terminology for Red Cell Surface Antigens [2,3]. Antigens are divided into systems (antigens controlled by a locus or closely linked loci) and three holding files : collections (related antigens whose genetic relationship is unknown), antigens of high incidence or antigens of low incidence. THE MAIEA TECHNIQUE Sometimes if an antigen has a very high or a very low incidence it is hard to relate it to other antigens or to assign it to a system. Immunochemical studies and in the case of high incidence antigens, use of cells of rare phenotype can be informative and recently the MAIEA technique, monoclonal antibody specific immobilisation of erythrocyte antigens, has proved useful. MAIEA was an adaptation of a technique, MAIPA, frequently used for studying platelets. MAIEA can be used to assign red cells antigens, as recognised by human alloantisera, to particular components of the red cell membrane [4]. Location of antigens on specific red cell membrane components The Knops system consists of 4 high incidence antigens Kna, McCa, Sla and Yka with frequencies greater than 90% in populations tested. There is also a low incidence antigen Knb found in Whites [3]. The antibodies to these public antigens are difficult to identify serologically. The antigens show a wide variation of strength on different donor’s cells. There is a null phenotype, the Helgeson phenotype, which appears from serological tests to lack all 4 antigens [5]. Cells which lack one Knops antigen may have weakened expression of other Knops antigens. The mists about these serologically difficult antigens were cleared when Moulds et al [6] and Rao et al [7] independently showed that these antigens were carried on the CR1 (complement receptor 1, CD35) protein. The related antigen Csa was not located on CR1, so Csa and Csb were left in the Cost collection [3]. » Dans Transfusion Immunology and Medicine, 188. CRC Press, 1995. http://dx.doi.org/10.1201/9781482273441-7.

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Actes de conférences sur le sujet "Null Reactions"

Benabdallah, Assia, Farid Ammar Khodja et Cedric Dupaix. « Null-controllability of some reaction-diffusion systems with one control force ». Dans Control Systems : Theory, Numerics and Applications. Trieste, Italy : Sissa Medialab, 2006. http://dx.doi.org/10.22323/1.018.0006.

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Hinata, Ryotaro, et Dragomir N. Nenchev. « Balance Stabilization with Angular Momentum Damping Derived from the Reaction Null-Space ». Dans 2018 IEEE-RAS 18th International Conference on Humanoid Robots (Humanoids). IEEE, 2018. http://dx.doi.org/10.1109/humanoids.2018.8624933.

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Hara, Naoyuki, Yoichi Handa et Dragomir Nenchev. « End-link dynamics of redundant robotic limbs : The Reaction Null Space approach ». Dans 2012 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 2012. http://dx.doi.org/10.1109/icra.2012.6224627.

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Nishio, Akinori, Kentaro Takahashi et Dragomir Nenchev. « Balance Control of a Humanoid Robot Based on the Reaction Null Space Method ». Dans 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems. IEEE, 2006. http://dx.doi.org/10.1109/iros.2006.282408.

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Chuangfeng, Huai, Fang Yuefa et Guo Sheng. « Gait Design and Balance Control for the Biped Robot Based on Reaction Null-space Method ». Dans 2007 Chinese Control Conference. IEEE, 2006. http://dx.doi.org/10.1109/chicc.2006.4347226.

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Yuguchi, Yudai, Kenji Nagaoka et Kazuya Yoshida. « Verification of gait control based on reaction null-space for ground-gripping robot in microgravity ». Dans 2016 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 2016. http://dx.doi.org/10.1109/icra.2016.7487444.

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Jiao, Chunting, Bin Liang et Xueqian Wang. « Adaptive reaction null-space control of dual-arm space robot for post-capture of non-cooperative target ». Dans 2017 29th Chinese Control And Decision Conference (CCDC). IEEE, 2017. http://dx.doi.org/10.1109/ccdc.2017.7978151.

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Hidaka, Yuki, Kajun Nishizawa et Dragomir N. Nenchev. « Dynamic Stepping on Unknown Obstacles With Upper-Body Compliance and Angular Momentum Damping From the Reaction Null-Space ». Dans 2019 International Conference on Robotics and Automation (ICRA). IEEE, 2019. http://dx.doi.org/10.1109/icra.2019.8793832.

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Fontana, Giorgio. « Generation of Gravitational Waves with Nuclear Reactions ». Dans SPACE TECH.& APPLIC.INT.FORUM-STAIF 2006 : 10th Conf Thermophys Applic Microgravity ; 23rd Symp Space Nucl Pwr & Propulsion ; 4th Conf Human/Robotic Tech & Nat'l Vision for Space Explor. ; 4th Symp Space Coloniz. ; 3rd Symp on New Frontiers & Future Concepts. AIP, 2006. http://dx.doi.org/10.1063/1.2169308.

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Yagui, Marcela, et Luís Maia. « Data mining of social manifestations in Twitter : An ETL approach focused on sentiment analysis ». Dans XIII Simpósio Brasileiro de Sistemas de Informação. Sociedade Brasileira de Computação, 2017. http://dx.doi.org/10.5753/sbsi.2017.6019.

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The objective of this study was to analyze sentiments of users of online social network twitter to understand how people manifested toward the article published by the magazine Veja on 04-18-16 entitled "bela, recatada e do lar" (beautiful, demure and from home) in an attempt to understand how this behavior evolved in two weeks and to assess which events had aroused greater reaction from people. To this end, a data mining technique known as sentiment analysis was used with the help of the ETL (Extract, Transform and Load) methodology and the Naive Bayes probabilistic learning algorithm. Moreover, the null hypothesis was formulated and tested to see whether two events that took place during the collection period influenced, in fact, the polarity of analyzed sentiments in the generated database.

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Rapports d'organisations sur le sujet "Null Reactions"

Ajzenman, Nicolás, Lenin Balza, Hernan Bejarano, Camilo De Los Rios et Nicolás Gómez Parra. Seemingly irrelevant factors and willingness to block polluting investments. Inter-American Development Bank, décembre 2023. http://dx.doi.org/10.18235/0005369.

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Using an online multi-country video-vignette survey experiment, we measure bias against extractive industries and foreign firms in individuals perceptions and preferences related to industrial projects with potential economic benefits and environmental costs. Individuals face a hypothetical industrial investment project with a randomly assigned implementing firm, which varies in one or two dimensions: nationality (foreign or national), and industrial sector (extractive or generic). We elicit several incentivized and non-incentivized measures of acceptance of hypothetical investments. We find a precisely estimated null effect on willingness to pay to block the projects across experimental treatments: respondents express similar reactions to the same information independently of the firms origin or industrial sector.

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