Multi-impurity adsorption model for modeling crystal purity and shape evolution during crystallization processes in impure media

Peer reviewed

High-Resolution In Situ Oxygen-Argon Studies of Surface Biological and Physical Processes in the Polar Oceans

The Arctic Ocean and Western Antarctic Peninsula (WAP) are the fastest warming regions on the planet and are undergoing rapid climate and ecosystem changes. Until we can fully resolve the coupling between biological and physical processes we cannot predict how warming will influence carbon cycling and ecosystem function and structure in these sensitive and climactically important regions. My dissertation centers on the use of high-resolution measurements of surface dissolved gases, primarily O2 and Ar, as tracers or physical and biological functioning that we measure underway using an optode and Equilibrator Inlet Mass Spectrometry (EIMS). Total O2 measurements are common throughout the historical and autonomous record but are influenced by biological (net metabolic balance) and physical (temperature, salinity, pressure changes, ice melt/freeze, mixing, bubbles and diffusive gas exchange) processes. We use Ar, an inert gas with similar solubility properties to O2, to devolve distinct records of biological (O2/Ar) and physical (Ar) oxygen. These high-resolution measurements that expose intersystem coupling and submesoscale variability were central to studies in the Arctic Ocean, WAP and open Southern Ocean that make up this dissertation.

Key findings of this work include the documentation of under ice and ice-edge blooms and basin scale net sea ice freeze/melt processes in the Arctic Ocean. In the WAP O2 and pCO2 are both biologically driven and net community production (NCP) variability is controlled by Fe and light availability tied to glacial and sea ice meltwater input. Further, we present a feasibility study that shows the ability to use modeled Ar to derive NCP from total O2 records. This approach has the potential to unlock critical carbon flux estimates from historical and autonomous O2 measurements in the global oceans.

Understanding the work of the city manager

The managerial behaviour approach to understanding managerial work has developed from research over the course of fifty years. The approach represents a marked departure from mainstream (and still prevalent) management approaches that depict management as a set of general composite functions. The managerial behaviour approach is distinctive in its empirical research background, object, focus and methodology. Its objective is to provide the simple answer to the complex question: what do managers do? However, the emphasis in the studies on managerial behaviour represents a limitation in so far as a context for locating and judging that behaviour is largely absent (Hales, 1986). This paper presents the results of initial research into managers operating in a different and largely neglected context - city councils. The research uses Mintzberg’s (1973) concept of behavioural roles as an analytical tool to explain and understand what city managers do. This study assesses whether these roles adequately capture the important features of managerial work in the city council. It is argued that while Mintzberg’s role framework is useful, structured observation alone does not adequately address the complexities of environments and styles of managers or the cognitive processes of managers. However, by integrating this approach with an appreciation of context and cognitive processes and how they can influence or affect managerial behaviour, we develop a more realistic description of what managers actually do and why they do it.

Is conscious awareness needed for all working memory processes?

Stein and colleagues argue there is no yet conclusive evidence for nonconscious working memory (WM) and that is critical to probe WM while ensuring null sensitivity to memory cues. While this stringent approach reduces the likelihood of nonconscious signaling for WM, we discuss existing work meeting this null sensitivity criteria, and, related work on nonconscious cognition in keeping with WM/awareness dissociations on the basis of a functional operational definition of WM. Further, because it is likely that WM is a nonunitary functional construct and visual awareness a gradual phenomenon, we propose that delineating the neural mechanisms for distinct WM types across different levels of awareness may prove the most fruitful approach for understanding the interplay between WM and consciousness.

Simulating Business Processes of Manufacturing SMEs on the Cloud

Simulating the efficiency of business processes could reveal crucial bottlenecks for manufacturing companies and could lead to significant optimizations resulting in decreased time to market, more efficient resource utilization, and larger profit. While such business optimization software is widely utilized by larger companies, SMEs typically do not have the required expertise and resources to efficiently exploit these advantages. The aim of this work is to explore how simulation software vendors and consultancies can extend their portfolio to SMEs by providing business process optimization based on a cloud computing platform. By executing simulation runs on the cloud, software vendors and associated business consultancies can get access to large computing power and data storage capacity on demand, run large simulation scenarios on behalf of their clients, analyze simulation results, and advise their clients regarding process optimization. The solution is mutually beneficial for both vendor/consultant and the end-user SME. End-user companies will only pay for the service without requiring large upfront costs for software licenses and expensive hardware. Software vendors can extend their business towards the SME market with potentially huge benefits.

Reconceptualising International Intervention: Statebuilding, ‘Organic Processes’ and the Limits of Causal Knowledge

This article examines the transformation in the conceptual understanding of international intervention over the last two decades. It suggests that this conceptual shift can be usefully interrogated through its imbrication within broader epistemological shifts highlighting the limits of causal knowledge claims: heuristically framed in this article in terms of the shift from policy interventions within the problematic of causation to those concerned with the management of effects. In this shift, the means and mechanisms of international intervention have been transformed, no longer focused on the universal application of Western causal knowledge through policy interventions but rather on the effects of specific and unique local and organic processes at work in societies themselves. The focus on effects takes the conceptualisation of intervention out of the traditional terminological lexicon of International Relations theory and instead recasts problems in increasingly organicised ways, suggesting that artificial or hubristic attempts at socio-political intervention should be excluded or minimised.

Female employment from the household. Towards a comprehensive analysis of work-life articulation

Research on women’s employment has proliferated over recent decades, often under a perspective that conceptualizes female labour market activity as independent of male presences and absences in the productive and reproductive spheres. In the face of these approaches, the article argues the need to focus on the couple as the unit of analysis of work-life articulation. After referring to the main theoretical arguments that, from a gender perspective within labour studies, have pointed out the relevance of placing the household as the central space for the analysis of the sexual division of labour, the article reviews different empirical contributions that have incorporated such perspective in the international literature. Next, the state of the art in the Spanish literature is presented, before arguing the desirability of applying such framework of analysis to the study of employment and care work in Spanish households, which are at present undergoing major transformations.

Questioning the merits and demerits of electronic communication in Social Work

This paper examines the social dynamics of electronic exchanges in the human services, particularly in social work. It focuses on the observable effects that email and texting have on the linguistic, relational and clinical rather than managerial aspects of the profession. It highlights how electronic communication is affecting professionals in their practice and learners as they become acculturated to social work. What are the gains and losses of the broad use of electronic devices in daily lay and professional, verbal and non-verbal communication? Will our current situation be seriously detrimental to the demeanor of future practitioners, their use of language, and their ability to establish close personal relationships? The paper analyzes social work linguistic and behavioral changes in light of the growth of electronic communication and offers a summary of merits and demerits viewed through a prism emerging from Baron’s (2000) analysis of human communication.

What's in it for us? A case study research about micro sense making processes through the eyes of front line employees, during culture change implementation

Abstract How employees make sense of change is a very complex process. Recently, academics have neglected to research sense making activities in a micro culture implementation context, through the eyes of front line employees. In contrast to a macro view, a micro perspective limits researchers to only look at an individual, departmental or group level. By doing so, we can zoom in on the details of sense making processes that employees use in their daily work life. A macro (organisational) view is based on the notion that there is a general integrated culture that can be found in all organisational units and departments. It is assumed that culture can be researched by using the entire organisation as one single research entity. This thesis challenges this assumption. In case of planned change it is usually the management community who are in charge of the change intervention. Because of their formal hierarchical position, they have the power to abort or initiate change programs. It is perhaps therefore that researchers tend to be focused on the management community rather than on lower level organisational members, such as front line employees. Apart from the micro view, scholars also neglected to research culture change implementation through the eyes of front line employees. This thesis is an attempt to fill these two gaps that currently exists in academic change management publications. The main research question is therefore: From a micro point of view how do front-line employees make sense of the impact of culture change, during the implementation phase? This thesis starts with a literature review which exposes the two main gaps. The most important outcome of this review is that only 2% of the research articles dealt with culture implementation, through the eyes of front line employees. A conceptual research model is built on the integrated sense making theory of Weber and Manning (2001) and the micro variables of Raelin and Cataldo (2011). These theories emphasize elements of sense making in a daily working context. It is likely that front line employees can identify themselves with research elements such as tasks, skills practices, involvement and behaviour. Front line employees were selected, because as lower level organisational members they are usually the change recipients. They are further away from the change initiating scene (usually the management of an organisation) and form a potential sense making ‘hotspot’ that could provide new academic insights. In order to carry out the primary research, two case organisations were selected in the leisure industry. A participative case study research method was chosen. This meant that the researcher worked in the concerning departments of the case organisations. The goal was to observe and interview front line employees, while they were performing their jobs. The most important advantage of this approach is that the researcher temporarily becomes one with the organisation and is therefore able to acquire both formal and informal narratives that front line employees use during sense making activities. It was found that front line employees make sense of organisational change by using a practical approach. They make sense of the change program by carrying out new tasks, developing new skills and sharing best practices. The most noticeable conclusion was that sense making activities predominantly take place at an individual level in relation to change acceptance. Organisational members tend to create a mental equation in order to weigh the advantages against the disadvantages. They evaluate whether the concerning change program is beneficial to them or not. For future research a sense making scheme model is suggested that is based on two methods: an introspection and an action method.

Designing Massive Open Online Learning Processes: The importance of the social element

This is a pre-print for personal use only. Please refer to the Springer website for the official, published version http://www.springer.com/978-3-662-52923-2

Work Extraction and Energy Storage in the Dicke Model

We study work extraction from the Dicke model achieved using simple unitary cyclic transformations keeping into account both a non optimal unitary protocol, and the energetic cost of creating the initial state. By analyzing the role of entanglement, we find that highly entangled states can be inefficient for energy storage when considering the energetic cost of creating the state. Such surprising result holds notwithstanding the fact that the criticality of the model at hand can sensibly improve the extraction of work. While showing the advantages of using a many-body system for work extraction, our results demonstrate that entanglement is not necessarily advantageous for energy storage purposes, when non optimal processes are considered. Our work shows the importance of better understanding the complex interconnections between non-equilibrium thermodynamics of quantum systems and correlations among their subparts.

Catalytic Processes Mediated by Metal−Organic Frameworks : Reactivity and Mechanistic Studies

The present thesis describes the development of heterogeneous catalytic methodologies using metal−organic frameworks (MOFs) as porous matrices for supporting transition metal catalysts. A wide spectrum of chemical reactions is covered. Following the introductory section (Chapter 1), the results are divided between one descriptive part (Chapter 2) and four experimental parts (Chapters 3–6). Chapter 2 provides a detailed account of MOFs and their role in heterogeneous catalysis. Specific synthesis methods and characterization techniques that may be unfamiliar to organic chemists are illustrated based on examples from this work. Pd-catalyzed heterogeneous C−C coupling and C−H functionalization reactions are studied in Chapter 3, with focus on their practical utility. A vast functional group tolerance is reported, allowing access to substrates of relevance for the pharmaceutical industry. Issues concerning the recyclability of MOF-supported catalysts, leaching and operation under continuous flow are discussed in detail. The following chapter explores puzzling questions regarding the nature of the catalytically active species and the pathways of deactivation for Pd@MOF catalysts. These questions are addressed through detailed mechanistic investigations which include in situ XRD and XAS data acquisition. For this purpose a custom reaction cell is also described in Chapter 4. The scope of Pd@MOF-catalyzed reactions is expanded in Chapter 5. A strategy for boosting the thermal and chemical robustness of MOF crystals is presented. Pd@MOF catalysts are coated with a protecting SiO2 layer, which improves their mechanical properties without impeding diffusion. The resulting nanocomposite is better suited to withstand the harsh conditions of aerobic oxidation reactions. In this chapter, the influence of the nanoparticles’ geometry over the catalyst’s selectivity is also investigated. While Chapters 3–5 dealt with Pd-catalyzed processes, Chapter 6 introduces hybrid materials based on first-row transition metals. Their reactivity is explored towards light-driven water splitting. The heterogenization process leads to stabilized active sites, facilitating the spectroscopic probing of intermediates in the catalytic cycle.

Navigating the Self in Diverse Work Contexts

Navigating the self is critical for working in a diverse world, in which different identities interact in social space. This chapter presents five theoretical perspectives on how individuals navigate the self in diverse organizational contexts—social identity, critical identity, (role) identity, narrative-as-identity, and identity work. We review these five prominent theoretical perspectives on identity processes in diverse contexts to explicate various ways in which individuals actively participate in the co-construction of their identities in diverse contexts. As a next step in research, identity, diversity, and relationship scholars are encouraged to inquire into the generativity of proposed tactics for navigating the self in order to identify pathways for cultivating more positive identities in diverse work settings. The examination of positive relational identities is considered a promising path for further inquiry in this domain.

Fibronectin/phosphorylcholine coatings on fluorocarboned surfaces: a study upon adsorption and grafting processes

Depuis ces dernières décennies, le domaine des biomatériaux a connu un essor considérable, évoluant de simples prothèses aux dispositifs les plus complexes pouvant détenir une bioactivité spécifique. Outre, le progrès en science des matériaux et une meilleure compréhension des systèmes biologiques a offert la possibilité de créer des matériaux synthétiques pouvant moduler et stimuler une réponse biologique déterminée, tout en améliorant considérablement la performance clinique des biomatériaux. En ce qui concerne les dispositifs cardiovasculaires, divers recouvrements ont été développés et étudiés dans le but de modifier les propriétés de surface et d’améliorer l’efficacité clinique des tuteurs. En effet, lorsqu’un dispositif médical est implanté dans le corps humain, son succès clinique est fortement influencé par les premières interactions que sa surface établit avec les tissus et les fluides biologiques environnants. Le recouvrement à la surface de biomatériaux par diverses molécules ayant des propriétés complémentaires constitue une approche intéressante pour atteindre différentes cibles biologiques et orienter la réponse de l’hôte. De ce fait, l’élucidation de l’interaction entre les différentes molécules composant les recouvrements est pertinente pour prédire la conservation de leurs propriétés biologiques spécifiques. Dans ce travail, des recouvrements pour des applications cardiovasculaires ont été créés, composés de deux molécules ayant des propriétés biologiques complémentaires : la fibronectine (FN) afin de promouvoir l’endothélialisation et la phosphorylcholine (PRC) pour favoriser l’hémocompatibilité. Des techniques d’adsorption et de greffage ont été appliquées pour créer différents recouvrements de ces deux biomolécules sur un polymère fluorocarboné déposé par traitement plasma sur un substrat en acier inoxydable. Dans un premier temps, des films de polytétrafluoroéthylène (PTFE) ont été utilisés en tant que surface modèle afin d’explorer l’interaction de la PRC et de la FN avec les surfaces fluorocarbonées ainsi qu’avec des cellules endothéliales et du sang. La stabilité des recouvrements de FN sur l’acier inoxydable a été étudiée par déformation, mais également par des essais statiques et dynamiques sous-flux. Les recouvrements ont été caractérisés par Spectroscopie Photoéléctronique par Rayons X, immunomarquage, angle de contact, Microscopie Électronique de Balayage, Microscopie de Force Atomique et Spectrométrie de Masse à Ionisation Secondaire à Temps de Vol (imagerie et profilage en profondeur). Des tests d’hémocompatibilité ont été effectués et l’interaction des cellules endothéliales avec les recouvrements a également été évaluée. La FN greffée a présenté des recouvrements plus denses et homogènes alors que la PRC quant à elle, a montré une meilleure homogénéité lorsqu’elle était adsorbée. La caractérisation de la surface des échantillons contenant FN/PRC a été corrélée aux propriétés biologiques et les recouvrements pour lesquels la FN a été greffée suivie de l’adsorption de la PRC ont présenté les meilleurs résultats pour des applications cardiovasculaires : la promotion de l’endothélialisation et des propriétés d’hémocompatibilité. Concernant les tests de stabilité, les recouvrements de FN greffée ont présenté une plus grande stabilité et densité que dans le cas de l’adsorption. En effet, la pertinence de présenter des investigations des essais sous-flux versus des essais statiques ainsi que la comparaison des différentes stratégies pour créer des recouvrements a été mis en évidence. D’autres expériences sont nécessaires pour étudier la stabilité des recouvrements de PRC et de mieux prédire son interaction avec des tissus in vivo.

Undersampled Critical Branching Processes on Small-World and Random Networks Fail to Reproduce the Statistics of Spike Avalanches

The power-law size distributions obtained experimentally for neuronal avalanches are an important evidence of criticality in the brain. This evidence is supported by the fact that a critical branching process exhibits the same exponent t~3=2. Models at criticality have been employed to mimic avalanche propagation and explain the statistics observed experimentally. However, a crucial aspect of neuronal recordings has been almost completely neglected in the models: undersampling. While in a typical multielectrode array hundreds of neurons are recorded, in the same area of neuronal tissue tens of thousands of neurons can be found. Here we investigate the consequences of undersampling in models with three different topologies (two-dimensional, small-world and random network) and three different dynamical regimes (subcritical, critical and supercritical). We found that undersampling modifies avalanche size distributions, extinguishing the power laws observed in critical systems. Distributions from subcritical systems are also modified, but the shape of the undersampled distributions is more similar to that of a fully sampled system. Undersampled supercritical systems can recover the general characteristics of the fully sampled version, provided that enough neurons are measured. Undersampling in two-dimensional and small-world networks leads to similar effects, while the random network is insensitive to sampling density due to the lack of a well-defined neighborhood. We conjecture that neuronal avalanches recorded from local field potentials avoid undersampling effects due to the nature of this signal, but the same does not hold for spike avalanches. We conclude that undersampled branching-process-like models in these topologies fail to reproduce the statistics of spike avalanches.