Relaxation of the silver/silver iodide electrode in aqueous solution

The aim of this study is to detect and characterize relaxation processes on silver/silver iodide electrodes in aqueous electrolyte solution. The information obtained is to be used for an estimation of the consequences of similar processes on colloidal AgI particles during encounter.In chapter 1 a general introduction is given. It is explained how electrode kinetic data can be used to obtain insight in the dynamic aspects of the stability of the lyophobic colloids.Some fundamental properties of the Ag/AgI film electrode which are important in the interpretation of the relaxation measurements are described in chapter 2. The preparation of the electrode, the silver layer and the AgI film is described. The specific resistance of the AgI film was obtained from measurement of the electrode resistance and the thickness of the AgI film. An estimation of the roughness factor of the AgI surface is made using electron micrographs and results of other investigators who worked with the same type of electrodes.In chapter 3 the relaxation behaviour of the Ag/AgI electrode in 0.1 M KNO 3 solution is described. The used pulse technique, the experimental set-up and the method of analysis are treated. It is shown that there are two relaxation processes: a fast one on the Psec scale and a slower one on the wee scale. They are probably connected with charge transfer processes in the Ag/AgI and AgI/ electrolyte solution interface respectively. The standard exchange current density and the transfer coefficient for the slow relaxation of both the Ag + and the I - reaction are calculated. The double layer capacitances are also obtained and their values agree with the results of other studies.Relaxation measurements in various KNO 3 concentrations ' and various types of inert electrolyte are reported in chapter 4. One of the main conclusions is that the slow relaxation is not influenced by the concentration and nature of the inert electrolyte.In chapter 5 an attempt is made to interpret the results obtained with the electrodes in terms of relaxation processes occurring at interacting AgI sol particles. It is indicated that some of the possible relaxation processes are fast as compared with the process of encountering of two colloid particles.Diffuse double layer relaxation in the aqueous solution and migration of interstitial silver ions in the solid are examples of such fast processes. On the other hand, the transfer of potential determining ions (silver or iodide ions) through the Stem layer is a rather slow process with a time constant which is lower than the particle encountering time by a factor of about ten. Thus, in the case of silver iodide sols, exchange of charge between particle and solution will not occur. However, redistribution of charge in the region of short distance between the interacting particles is possible via the fast relaxation processes. Thus, the silver iodide colloid appears to be intermediate between the constant charge case and the constant potential case.<p/

Epidote U–Pb geochronology and isotope geochemistry to trace the hydration of the continental crust in orogens

This work investigates epidote veins in crystalline rocks to date fluid circulation in the granitic continental crust, and to gain insight into fluid pathways and sources. Fluids are crucial in the tectono-metamorphic evolution of rocks because they control deformation processes, mineral reactions and heat transfer. Earth’s continental crust is dominated by primarily water-poor granitic rocks. The observation that granitoids in many orogens (e.g., Alps, Himalayas) contain metamorphic hydrous minerals attests to the introduction of fluids into these primarily “dry” rocks. However, whether this occurred during prograde, peak or retrograde metamorphism is often unclear. One way to reconstruct the timing of fluid circulation is by dating veining events. In addition to time constraints, many vein-filling minerals return useful information regarding fluid sources and pathways by stable and radiogenic isotope geochemistry. We assess and demonstrate the potential of epidote [i.e., Ca2Al2(Al,Fe3+)Si3O12(OH)] in veins to date and trace hydration of the granitic continental crust of the Alps from Permian to Miocene times. Epidote U–Pb geochronology is made possible by combining U–Pb isotope measurements by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) with the Tera–Wasserburg diagram. This approach is suitable for high-initial Pb minerals like epidote, and it returns geologically meaningful ages dating the formation of epidote during veining. Allanite (i.e., REE-rich monoclinic epidote) is used as an LA-ICP-MS reference material with no noticeable matrix effects at the available analytical precision. This is a fundamental aspect of U–Pb dating by in-situ techniques, because no well-characterized epidote standard exists for U–Pb isotope analyses, and uncorrected matrix-effects cause grossly inaccurate U–Pb ages in high-initial Pb minerals. The application of this new protocol for epidote U–Pb dating to selected case studies establishes epidote as a powerful geochronometer and fluid tracer in the granitic continental crust. One group of investigated epidote-bearing veins are located in an inverted passive continental margin (i.e., Err nappe) in the eastern Swiss Alps. Surprisingly, in the Err nappe, such epidote veins formed in Late Cretaceous to Paleocene times during the compressional and extensional phases of the Eo-Alpine orogeny, and not during rifting. Epidote Pb–Sr isotope geochemistry reveals that the epidote-forming fluids interacted with carbonatic rocks during percolation into the crust along extensional faults, and O–H isotope data in epidote suggest that the fluids originated as modified seawater with the addition of a sedimentary-water component. The second group of studied epidote veins are from the Aar Massif, the inverted European passive continental margin. Here, epidote veins were produced by pre-orogenic Permian and syn-orogenic Miocene fluid circulation events. Hydrogen isotope data of Permian epidote indicates a meteoric origin for the Permian fluids, which likely percolated into the crust along rift-related normal faults and modified its hydrogen isotope composition interacting with syn-rift sediments. The combination of epidote U–Pb geochronology and Pb–Sr isotope geochemistry with microstructural analysis and trace element data also reveals epidote dissolution–precipitation processes during viscous granular flow in an epidote-quartz vein. Such processes are mediated by a combination of recycled and newly added fluids, whose mixed isotope composition is recorded by newly precipitated syn-kinematic epidote. This study demonstrates that epidote is an active participant in deformation processes in deforming polymineralic aggregates. This work demonstrates that the application of the newly developed protocol for epidote U–Pb dating, coupled with microstructural analysis, trace element data and isotope geochemistry, allows to characterize fluid circulation in inverted passive continental margins from rifting and across orogenic cycles. Epidote is ubiquitous in Earth’s crust: not only as metamorphic mineral, but also in ore deposits, in geothermal fields, and as alteration mineral in basalts and feldspars. The application of the tools presented here to epidote from other geological contexts may further establish this mineral as the key tracer of low-temperature fluid circulation

Efectos de estrés por calor sobre la performance de los cultivos y herramientas para el mejoramiento genético de tolerancia

Abiotic stress is one of the most common causes of crop deficit and loss and hence an important area of study. Moreover, concerns regarding global climate change over past decades mean the study of different abiotic stresses appears to be essential if its effects are to be mitigated. The current review covers the effects of heat stress on crop performance, the response crops make when subjected to this stress and the development of tools designed to breed for stress tolerant crops. Distinct levels of the problem are considered, from the morphological/anatomical, through the physiological and to the biochemical/molecular. The study of heat shock proteins (HSPs), quantitative trait loci (QTLs) identification and the relationship between metabolomics (OMICS) and heat stress are given special consideration.Considerando el estrés abiótico como una de las causas más comunes de déficit y las pérdidas de las cosechas resulta muy importante investigar a fondo esta temática. Por otra parte, teniendo en cuenta que los cambios climáticos globales son uno de los problemas que se enfrentan en las últimas décadas, el estudio de los diferentes tipos de estrés abiótico es esencial. La presente revisión se refiere a los efectos del estrés por calor sobre la performance de los cultivos, la respuesta generada por ellos sujetos a este estrés y el desarrollo de herramientas diseñadas para el mejoramiento genético de cultivos tolerantes al mismo. Se consideran distintos niveles de la problemática, desde lo morfológico/anatómico, a través de lo fisiológico y a lo bioquímico/molecular. Se presta especial consideración al estudio de las proteínas de choque térmico (HSPs), a la identificación de los loci de caracteres cuantitativos (QTLs) y a la relación entre la metabolómica (OMICS) y el estrés térmico

Heat stress effects on crop performance and tools for tolerance breeding

Abiotic stress is one of the most common causes of crop deficit and loss and hence an important area of study. Moreover, concerns regarding global climate change over past decades mean the study of different abiotic stresses appears to be essential if its effects are to be mitigated. The current review covers the effects of heat stress on crop performance, the response crops make when subjected to this stress and the development of tools designed to breed for stress tolerant crops. Distinct levels of the problem are considered, from the morphological/anatomical, through the physiological and to the biochemical/molecular. The study of heat shock proteins (HSPs), quantitative trait loci (QTLs) identification and the relationship between metabolomics (OMICS) and heat stress are given special consideration.Considerando el estrés abiótico como una de las causas más comunes de déficit y las pérdidas de las cosechas resulta muy importante investigar a fondo esta temática. Por otra parte, teniendo en cuenta que los cambios climáticos globales son uno de los problemas que se enfrentan en las últimas décadas, el estudio de los diferentes tipos de estrés abiótico es esencial. La presente revisión se refiere a los efectos del estrés por calor sobre la performance de los cultivos, la respuesta generada por ellos sujetos a este estrés y el desarrollo de herramientas diseñadas para el mejoramiento genético de cultivos tolerantes al mismo. Se consideran distintos niveles de la problemática, desde lo morfológico/anatómico, a través de lo fisiológico y a lo bioquímico/molecular. Se presta especial consideración al estudio de las proteínas de choque térmico (HSPs), a la identificación de los loci de caracteres cuantitativos (QTLs) y a la relación entre la metabolómica (OMICS) y el estrés térmico

Efectos de estrés por calor sobre la performance de los cultivos y herramientas para el mejoramiento genético de tolerancia

Abiotic stress is one of the most common causes of crop deficit and loss and hence an important area of study. Moreover, concerns regarding global climate change over past decades mean the study of different abiotic stresses appears to be essential if its effects are to be mitigated. The current review covers the effects of heat stress on crop performance, the response crops make when subjected to this stress and the development of tools designed to breed for stress tolerant crops. Distinct levels of the problem are considered, from the morphological/anatomical, through the physiological and to the biochemical/molecular. The study of heat shock proteins (HSPs), quantitative trait loci (QTLs) identification and the relationship between metabolomics (OMICS) and heat stress are given special consideration.Considerando el estrés abiótico como una de las causas más comunes de déficit y las pérdidas de las cosechas resulta muy importante investigar a fondo esta temática. Por otra parte, teniendo en cuenta que los cambios climáticos globales son uno de los problemas que se enfrentan en las últimas décadas, el estudio de los diferentes tipos de estrés abiótico es esencial. La presente revisión se refiere a los efectos del estrés por calor sobre la performance de los cultivos, la respuesta generada por ellos sujetos a este estrés y el desarrollo de herramientas diseñadas para el mejoramiento genético de cultivos tolerantes al mismo. Se consideran distintos niveles de la problemática, desde lo morfológico/anatómico, a través de lo fisiológico y a lo bioquímico/molecular. Se presta especial consideración al estudio de las proteínas de choque térmico (HSPs), a la identificación de los loci de caracteres cuantitativos (QTLs) y a la relación entre la metabolómica (OMICS) y el estrés térmico.Fil: Peverelli, M. Cecilia. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de AgronomíaFil: Rogers, W. John. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomí

Green branding effects on consumer response:examining a brand stereotype-based mechanism

Purpose This study aims to develop a comprehensive conceptual framework to investigate how green brand positioning strategies positively impact consumer response. It focusses on uncovering the causal mechanism in which such effect is mediated by brand stereotypes. Additionally, it outlines the moderating role of construal level in this formation process. Design/methodology/approach Three experimental studies were conducted to examine the hypotheses. Study 1 tests the positive influence of green brand positioning on consumer response. Study 2 tests the dual mediating effect of warmth and competence in the relationship between green brand positioning and consumer response. Study 3 further examines the moderating role of construal level in the effects of green brand positioning on brand stereotypes. Findings The findings reveal that green emotional positioning strategies are predominantly stereotyped as warm while green functional positioning strategies are predominantly stereotyped as competent. Both warm and competent mediate the effects of green brand positioning on consumer response. Furthermore, a congruency between green emotional positioning and high-level construal, as well as the match between green functional positioning and low-level construal, leads to more warmth and competence perception. Originality/value This study contributes to green brand management literature by proposing a brand stereotype-based mechanism to explain how green brand positioning strategies trigger consumers’ stereotyping process, leading to positive consumer response. This study also identifies the construal level as a moderating variable that impacts consumers’ warmth and competence perceptions towards two kinds of green brand positioning strategies. Managerially, the findings of this study provide managerial ideas for developing green branding strategies

Port of Rotterdam in Chinese Eyes

The Port of Rotterdam is a typical European organisation that undertakes several activities towards China annually and has a clear understanding of what it has to offer to its Chinese counterparts, but does not always succeed in achieving rapport with those counterparts. This paper studies the identity constructs of the Port of Rotterdam in a selected number of Chinese contexts (central ministries, main ports, etc.). The methodology is narrative analysis using corpora of texts compiled for each context. The core theoretical principle1 is that identity is not a property, but a process of ongoing interaction. The identity of A can only be established in a particular context, by observing the interaction between A and parties in that context. A will thus obtain multiple identities in multiple contexts. The results can be used by the Port of Rotterdam to improve the effectiveness of its delegations to China