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Impact of Biochar Amendment, Hydraulic Retention Time, and Influent Concentration on N and P Removal in Horizontal Flow-Through BioreactorsColeman, Brady S. 19 January 2018 (has links)
The advent of industrial, fertilizer-intensive agriculture during the 20th century has promoted export of anthropogenic nutrients, spurring degradation of ecosystem biodiversity and water quality. Exported nitrogen and phosphorus are recognized drivers of this deterioration, and require management. In the mid-1990s, denitrifying bioreactors (DNBRs), a subsurface, edge-of-field best management practice (BMP) that intercepts and treats agricultural drainage by supporting nitrate-attenuating denitrification with a saturated, carbon-filled substrate, were developed. Since then, their utility has expanded, and recent studies have unearthed biochar's capability to stimulate simultaneous nitrate (NO3--N) and phosphate (PO43--P) removal in DNBRs. This study investigated biochar's potential as an amendment to the traditional woodchip media by conducting nine, five-day trials on twelve laboratory-scale, horizontal flow-through DNBR columns. Three media types were tested: woodchips (W), 90% woodchips and 10% biochar (B10), and 70% woodchips and 30% biochar (B30). Simulated agricultural drainage with four unique concentration combinations of 16.1 and 4.5 mg L-1 NO3--N and 1.9 and 0.6 mg L-1 PO43--P was delivered at hydraulic retention times (HRTs) of 3, 6, and 12 h. Mean NO3--N removal efficiencies ranged from 16.9%-93.7%, and media type was insignificant at low influent NO3--N concentrations, but B30 was the most effective at high influent NO3--N concentrations. Mean PO43--P removal efficiencies ranged from -122.0%-74.9%, with B10 and B30 significantly worse than W at removing PO43--P. These findings corroborate previous work indicating boosted NO3--N removal with biochar, but contradict studies upholding PO43--P-removing capabilities. / Master of Science
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Performance Analysis of an Urban Stormwater Best Management Practice RetrofitSimko, Andrew Jack 22 September 2014 (has links)
Historically, the primary objective of traditional stormwater best management practices (BMPs) was to attenuate peak runoff discharges from urban areas. There has been growing demand to construct BMPs that improve stormwater runoff quality to reduce pollutant loading into downstream water bodies. A BMP located in Herndon, Virginia was retrofitted in 2009. Previously a dry detention pond, the new BMP design contains permanent wet pools as well as elements of Low Impact Development practices. A performance analysis was conducted on the retrofit to determine if the BMP was removing pollutants from stormwater runoff. Two mass-based methods were utilized for the performance analysis: the Summation of Loads Method and Effluent Probability Method. The Kaplan-Meier method and Robust Regression on ordered statistics (ROS) were used to make it possible to include censored datasets in the analysis. Analysis with the SOL method showed removal of suspended sediment, nitrogen, iron, and copper. Export of dissolved solids, phosphorus, organic carbon, and manganese was observed. The results of the Effluent Probability Method showed statistically significant reductions of sediment, iron, and copper across the entire range of monitored storm event sizes (p-value≤0.05). There was no statistical difference between the influent and effluent loads of nitrogen. Negative performance of dissolved solids, phosphorus, organic carbon, and manganese were observed for the entire range of monitored storm event sizes. The results of both methods indicated that the BMP retrofit is effectively removing sediment but failing to achieve significant nutrient reductions. This may be due to the creation of anoxic conditions from the oxygen demand of the micropool sediments and microbial degradation of vegetation within the BMP. Removal of the sediment bed and harvesting of the vegetation would likely improve the performance of the BMP. / Master of Science
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Assessing Landowner Level Costs for Riparian Forest Buffer System Adoption on Farms in Virginia's Chesapeake Bay WatershedSmith, Clifton Lee Jr. 18 August 1998 (has links)
Riparian Forest Buffer Systems contribute to non-point source pollution control and improve the physical and trophic qualities of streams. There is a limited understanding of the full range of costs incurred when implementing a RFBS. Establishment costs will vary with the site characteristics. The amount of forgone income will vary with the current land-use. RFBS enterprises may yield returns that partially or fully offset forgone income. Section A discusses the physical characteristics and functions of RFBS in the Chesapeake Bay Watershed. Section A argues that RFBS design and site characteristics alter the physical ability of RFBS to produce environmental services. Altering design specifications may come at little environmental loss but might greatly reduce landowner costs. Section B describes a decision support system that can provide landowners and policy makers with financial information on the site specific changes in costs that occur as RFBS designs are altered. Section C utilizes the decision support system software to simulate the common design and site characteristics found within the Chesapeake Bay Watershed of Virginia. Generalizations are drawn concerning reduction efficiencies of a RFBS based on the physical characteristics of the regions. Section D discusses government policies and incentive programs, as well as additional private income opportunities, that may influence the cost and adoption of RFBS. Findings revealed a range of annual per acre cost of adoption between $140.09 rising to a positive return of $124.79, depending on assumptions of site characteristics, land-use, and supplemental financial incentives. / Master of Science
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The appropriation of ideas, concepts and models by management practitionersRobinson, Laurence January 2010 (has links)
During the second half of the 20th century there has been both a burgeoning intellectual interest in business and management as a topic and an exponential growth in the formal study of business and management as an academic subject. Indeed by the end of the century it was estimated that worldwide there were 8,000 business schools and more than 13 million students of business and management. In addition, it was estimated that worldwide annual expenditure on university level business and management education had reached US $15 billion (The Global Foundation for Management Education, 2008). However, despite this there is a lack of clarity regarding both the scale and the nature of the influence that academic scholarship exerts over managers. Accordingly this research study has sought to investigate the appropriation of ideas, theories, concepts and models by management practitioners. The thesis has reviewed and evaluated the two most obvious, most established and most influential potential explanations. These were diffusion of innovations (Rogers, 1962) and fashion theory (Abrahamson, 1991 & 1996; Abrahamson & Fairchild, 1999). It has been concluded that whilst both these potential explanations provided important insights, neither was able to provide a comprehensive theoretical foundation for this research study. Accordingly, a much broader range of pertinent scholarship was reviewed and evaluated. This included, but is not limited to, the scholarship that is associated with learning by adults (Dewey, 1933; Bartlett, 1967; Schank & Abelson, 1976; Mezirow, 1977). Although this additional scholarship provided a further range of potential explanations, the extent to which any of these would be found within the particular setting of management practitioners remained unclear. In addition, the literature review highlighted a number of unresolved debates regarding issues such as (i) whether management was a science or an applied science; (ii) whether it was a craft or a profession; (iii) whether in reality there were fashionable trends in management practice or whether in fact such practices were remarkably stable; and (iv) whether management theoreticians, gurus and consultants actually exerted significant influence over management practitioners. The literature review also highlighted methodological concerns relating to the use of citation analysis as a proxy for primary information regarding managerial practice. Hence, this research is situated in a gap which is delineated by the unresolved issues that are associated with both diffusion theory and fashion theory; the applicability of the broader range of scholarship to a management setting; the unresolved debates within this field of interest and the need to obtain primary information relating to management practice, rather than being dependant upon citation analysis. The research study has utilised qualitative data and inductive reasoning to examine these matters and the overarching research philosophy has been that of realism (Ritchie & Lewis, 2003). Ultimately, 39 semi-structured, recorded interviews were undertaken using the critical incident technique (Flanagan, 1954). Collectively these interviews lasted for 35 hours and obtained information relating to 160 critical incidents. The verbatim transcripts of the interviews totalled 350,000 words. A case study analysis of this data was undertaken to examine the decision making of the interviewees in relation to some of their most challenging managerial situations. This analysis concluded that for the ‘generality’ of these interviewees; theory played little, or no, overt part in their decision making. The data was also subjected to a content analysis using a bespoke compendium of 450 ‘terms’ that represented the development of theorising about management over the whole of the 20th century. This analysis concluded that the influence of the 20th century’s management theoreticians over these interviewees was weak. Finally, the possibility that any such influence might be a covert, rather than an overt; phenomenon was examined using both the insights of intertextuality (Allen, 2000; Bazerman, 2004) and the framework analysis technique (Ritchie, Spencer & O’Connor, 2003). This analysis demonstrated that the discourse, dialogue and language of these interviewees could be indexed to four domains; (i) the theoretical; (ii) the conceptual; (iii) the tactical; and (iv) the practical. The intertextual indexing outcomes were corroborated both by substantial extracts from the verbatim interview transcripts and by three unrelated strands of scholarship. These were (i) adaptive memory systems (Schacter, 2001); (ii) the realities of management (Carlson, 1954; Stewart, 1983; Mintzberg, 1989) and (iii) the role of concepts and conceptual thinking in nursing (McFarlane, 1977; Gordon, 1998; Orem, 2001). On this basis it has been concluded that management can be characterised as a conceptual discipline; that in its essential nature management is at least as conceptual as it is either theoretical or practical; and that managers appropriate concepts and ideas, rather than theories and models per se.
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The impacts of human land-use change on avian diversity and associated ecosystem functionsBregman, Tom P. January 2014 (has links)
Understanding the impacts of land-use change on biodiversity and the ecosystem services that it provides is of great importance given unprecedented growth of the human population. Past studies attempting to explore these impacts have described the overall structure of communities (i.e. species richness and trait diversity) across gradients of local scale degradation and fragmentation, and have sought to identify whether the loss of species following land-use change is non-random. Yet, despite a wealth of research we still lack a generalised understanding of how land-use change impacts on traits responsible for determining species sensitivity and their role within ecosystems, particularly for vertebrates. Moreover, despite the importance of niche-based processes in the assembly of communities, we have not yet elucidated whether these are important in mediating the collapse of communities in human-dominated landscapes. To fill these existing research gaps, I collated comprehensive avian species inventories from fragmented and degraded forests and compared their structure with communities existing in continuous forests. In Chapter 2, I tested whether sensitivity of species to forest fragmentation varies between the temperate zone and the tropics and whether there are key differences in the size of fragments required to maintain ecosystem processes in these regions. I found that sensitivity to fragmentation varies according to functional group and body mass, with the prevalence of insectivores and large frugivores declining in relation to fragment size, particularly in tropical fragments smaller than 100 ha. In Chapter 3, I tested whether functional diversity and the mean position of trait diversity of insectivores and frugivores, changed across a gradient of intensifying land-use change. I found a decline in the functional diversity of forest species and a shift in the mean community traits for both forest and non-forest species. In Chapter 4, I tested whether the structure of tropical bird communities are influenced by species interactions in a fragmented landscape. I found increasing over-dispersion in functional and phylogenetic trait relatedness among species with decreasing fragment size, suggesting that competitive interactions are important in the disassembly of avian communities. In Chapter 5, I modelled the impact of forest cover change on ecosystem function across the Brazilian Amazon, focusing on seed dispersal by birds. Furthermore, I tested whether ecosystem function declined linearly with decreased forest cover after accounting for differences in the underlying pools of species. I found the lowest levels of functional diversity along the southern arc of deforestation and that the dispersal of large seeds showed some resilience to declining forest cover. Taken together, my results suggest that the loss of species from communities in degraded and fragmented landscapes is strongly non-random. Insectivores and large frugivores are most sensitive to land-use change, with species located in the densest parts of trait space being most threatened by a decline in forest patch size, suggesting that species interactions regulate the collapse of avian diversity in human-modified forests. I conclude that land-use change has important implications for the provisioning of ecosystem services, including seed dispersal and the control of insect herbivores. The impact of future land-use change is likely to be mediated by the composition of the original pool of species and the amount of redundancy in the ecosystem services that they provide. I discuss the relevance of my findings to land-use management strategies and policy interventions, and in particular conclude that these should, where possible, maintain pristine forest patches above 1000 ha, improve connectivity among habitat patches, and ensure greater protection for logged and burnt forests. Future studies should focus on clarifying the link between shifts in vertebrate community structure and the functioning of forest ecosystems.
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An analysis of alternative soil, nutrient, and water management strategies.Smith, Craig Matthew January 1900 (has links)
Doctor of Philosophy / Department of Agricultural Economics / Jeffery R. Williams / The two topics addressed in this dissertation are both related to surface water quality. Reservoir sedimentation and water quality trading are examined from economic and environmental perspectives. Each topic and the resulting policy implications are relevant to stakeholders at the local, state, and federal levels.
Reservoir sedimentation has been recognized as a major environmental, social, and economic issue in much of the Midwestern US. There is an effort to focus public and private funds to achieve the greatest return on the investment from soil erosion and sediment reduction strategies. How can physiographical and economic relationships within the watershed be quantified in such a way to provide insights into the selection of alternative management strategies? This study focuses on answering that question by integrating a physically-based watershed model with an economic analysis of alternative sedimentation reduction strategies for the case of Tuttle Creek Lake located in northeastern Kansas.
Several key finding of this study are that both physiographical and economic factors must be considered for cost-effective conservation to occur. Considering these factors and targeting BMP implementation from 8 to 23 times more cost-effective than random implementation. If targeting cannot be done effectively or if “intangible” costs of BMP implementation are too large, dredging is likely to be more cost-effective. While this research compares the cost-effectiveness of various BMP implementation approaches in Kansas with dredging, the benefits associated with each of these strategies is not addressed.
While there is substantial evidence that nonpoint sources have lower nutrient reduction costs than point sources, experience with water quality trading (WQT) reveals a common theme: little or no trading activity. These outcomes suggest the presence of obstacles to trading that were not recognized in the design of existing programs.
To examine the ways that various market imperfections may impact the performance of a WQT market, an agent-based model is constructed, which simulates a hypothetical point-nonpoint market. This study first presents an overview of the concepts and simulation modeling technique used and then analyzes the effects of two prominent market impediments identified in the WQT literature: information levels and trading ratios.
The results imply that if market designers feel that only a limited number of trades will be consummated, creating an institution that provides accessible information about buyers’ prices is preferred to providing information about sellers’ prices. Overall, more information is always better, but it becomes less important with higher trading ratios.
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Assessing Phosphorus Sources with Synoptic Sampling in the Surface Waters of a Mixed-Use, Montane WatershedPearce, Austin Willis 01 May 2017 (has links)
Few elements in surface waters are monitored as closely as phosphorus (P) due to its role in the eutrophication and degradation of surface waters. Limiting P mobilization from source areas is, therefore, a central goal of water quality protection plans. But the work of locating sources in mixed-use watersheds is challenged by the spatial and temporal variability of critical source areas (CSAs) of P. Synoptic sampling is a proven method for capturing the spatial variation of water quality parameters in surface waters, though it's not often used to track temporal dynamics across the same study area. Phosphorus fractionation is an analytical method that divides the total P (TP) in water into fractions, which for this study included total dissolved P (TDP), particulate P (PP), dissolved reactive P (DRP), and dissolved organic P (DOP). The objective of this study was to demonstrate the utility of combining temporally repeated synoptic sampling with simple P fractionation as a unique strategy for locating and characterizing CSAs of P. Seven synoptic sampling campaigns were conducted over a two-year period (March 2015 – July 2016) in a rural, montane watershed in north central Utah, USA. In each campaign, we sampled 18 sites across three tributaries (Main Creek, Spring Creek, and Little Hobble Creek) during three distinct, annual hydrologic periods (rising flow, peak flow, and baseflow). Temporal repetition clearly identified the rising flow period as the period with greatest P loading in the watershed. Combining repeated synoptic sampling and P fractionation successfully identified CSAs of P and most probable transfer pathways. Specifically, stream segments along lower Spring Creek and Main Creek were associated with the greatest increases of PP loads during periods of rising flow and peak flow. In the same time periods, the greatest DOP loads stemmed from forested areas as well as areas in the lower watershed associated with winter grazing of cattle. The watershed exhibited a significant background concentration of DRP from groundwater-driven subsurface sources in the lower half of the watershed that persisted year-round. These assessments can be used to develop management practices that limit various P loads from these respective critical source areas. The characterization of CSAs could not have been made using only a traditional synoptic sampling approach. This study demonstrated that the combination of repeated synoptic sampling and P fractionation can be an effective technique for locating and characterizing critical P source areas in order to guide best management practices that improve surface water quality.
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Making Mobile Meaning : expectations and experiences of mobile computing usefulness in construction site management practiceLöfgren, Alexander January 2008 (has links)
During the last decade, anticipated and realized benefits of mobile and wireless information and communication technology (ICT) for different business purposes have been widely explored and evaluated. Also, the significance of ‘user acceptance’ mechanisms through ‘perceived usefulness’ of ICT applications has gained broad recognition among business organizations in developing and adopting new ICT capabilities. However, even though technology usefulness is regularly highlighted as an important factor in ICT projects, there is often a lack of understanding of what the concept involves in the practical work context of the actual users, and how to deal with the issues of usefulness in organizational ICT development processes. This doctoral thesis covers a 1,5 year case study of a mobile computing development project at a Swedish international construction enterprise. The company’s mobile ICT venture addressed the deficient ICT use situation of management practitioners in construction site operations. The study portrays the overall socially shaped development process of the chosen technology and its evolving issues of usefulness for existing construction site management practice. The perceived usefulness of mobile computing tools among the ‘user-practitioners’ is described as emergence of ‘meaningful use’ based on initial expectations and actual experiences of the technology in their situated fieldwork context. The studied case depicts the ongoing and open-ended conversational nature of understanding adequate ICT requirements in work practice, and the negotiation of mobile computing technology design properties between users and developers over time towards the alignment of diverse personal, professional and organizational needs and purposes of ICT use. The studied introduction of mobile computing technology in construction site management fieldwork practice serves as an illustrative actual example of how to interpret, understand and approach issues of usefulness and user acceptance of ICT resources in operative work contexts when managing ICT development processes in organizations. / QC 20100825
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Effectiveness of a collaborative case management education program for Taiwanese public health nursesLiu, Wen-I January 2007 (has links)
Taiwanese health authorities are increasingly applying case management as a health care delivery strategy in the community. However, most Taiwanese public health nurses (PHNs) do not receive case management education because there are few education programs available. Several limitations in existing evaluative studies of case management continuing education programs were identified. These methodological weaknesses limit the conclusions that can be drawn about the effectiveness of these education programs. Hence, the purpose of this study was to develop, implement and evaluate a collaborative case management continuing education program for Taiwanese PHNs. The study was divided into three phases, with an expanded theoretical framework used to guide the program development, implementation and evaluation. Phase One conducted focus group discussions in order to assess the educational needs of Taiwanese PHNs. Phase Two developed a collaborative education program based on the findings of a literature review and the needs assessment. The initial program was evaluated by an expert panel and pilot testing was undertaken. Phase Three implemented and evaluated the program using an experimental research design and mixed evaluation methods. Three outcome levels were assessed, namely reaction, learning and performance by examining changes in PHNs' case management knowledge, skills and practice. The participants in the study were PHNs employed in health centres in Taipei City. The program itself involved 16 hours of workshops through four half-day sessions, conducted every two weeks during the participants' work time and at their workplace. Two types of data, focus group data and questionnaire data, were collected during the course of the study. The focus groups were conducted before and after the program delivery, for the needs assessment and program evaluation, using a subset of the participants. The focus groups were moderated by the researcher, who used a focus group discussion guide to collect data. The other data set was collected using self-report questionnaires. The participants were randomly allocated into two groups using cluster sampling, the experimental and comparison groups. Both groups were given questionnaires before the education program commenced, and then again eight weeks after the program was completed. For ethical considerations, PHNs in the comparison group also received the same program after data collection. The results revealed that the majority of participants were satisfied with the program. The education intervention significantly improved PHNs' case management knowledge, performance skills confidence, preparedness for case manager role activities, frequency of using case management skills, and frequency of using these role activities. A number of changes in case management practice were reported, in particular that the participants tended to follow the case management process more often and focus more on the quality of case management. This study was guided by an integrated theoretical framework, and used a clustered randomised controlled design to assess the effectiveness of the program across multiple levels of outcomes, hence addressing the design deficits identified in the prior evaluative studies. This study therefore provides an important contribution to the fields of nursing and case management by developing, implementing and evaluating a case management education program. Additionally, the program itself offers an evidence-based educational experience for PHNs and provides a new tool for nursing education in the context of Taiwan.
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Entre discours stratégique et pratique organisationnelle : une mise en intrigue de la gestion des connaissances dans la Branche Ciment / Between strategic discourse and organizational practice : an emplotment of knowledge management in the Cement DivisionCorbett, Isabelle 17 November 2009 (has links)
Les travaux autour de l’instrumentation gestionnaire sont le point d’entrée de cette recherche (Moisdon et al., 1997 ; Hatchuel et Weil, 1992 ; David, 1996, 1998). Nous nous intéressons à la coévolution d’une pratique de gestion, le knowledge management (KM), et d’une organisation. En résumant nos questions de recherche par la formule : « comment peuton faire du KM ? », nous interrogeons à la fois les différentes approches possibles de la gestion des connaissances, mais aussi les raisons qui conduisent une organisation à adopter le KM. Pour ce faire, nous menons une analyse multi-niveaux qui tient compte du contexte institutionnel, organisationnel et interindividuel. Dans ce cadre, nous mobilisons plusieurs littératures - institutionnalisme, outils de gestion, modes de consommation, théories managériales des organisations multinationales, régulation sociale - afin de parvenir à une compréhension globale des dynamiques d’un dispositif de gestion des connaissances au sein d’une organisation. Les dynamiques du dispositif de gestion sont étudiées à travers la mise en intrigue (Ricoeur, 1983) de la gestion des connaissances dans la Branche Ciment du groupe Lafarge. L’intrigue - pourquoi le KM ? - s’articule autour des enjeux stratégiques de l’industrie cimentière et de l’organisation de la fonction d’expertise technique. .Elle est le prélude aux différents récits qui content l’histoire du KM dans la Branche Ciment selon différentes perspectives spatiales et temporelles. A l’issue de cette recherche, il s’avère que le rôle principal du dispositif de gestion des connaissances est celui d’accroître la légitimité de l’entreprise vis-à-vis de son environnement externe et interne. Le dispositif KM est un outil au service d’un centre fort, qui se veut détenteur des connaissances. Nous avons documenté le basculement du dispositif de gestion fondé sur une logique de personnalisation, de gestion des compétences et d’autonomie vers une logique de codification, de gestion de l’information et de prescription. Le dispositif, figé dans une régulation de contrôle, se heurte à la régulation autonome des membres de l’organisation qui s’exprime à travers la résistance à la codification. Le conflit entre ces deux régulations entraîne une crise qui se traduit notamment par le mal-être des experts. Cependant le découplage soigneusement maintenu entre le dispositif de gestion des connaissances et l’activité réelle des opérations permet le maintien du statuquo. Au final, le cas de la Branche Ciment illustre un cas de domination stratégique. En l’absence de régulation conjointe, c’est le découplage entre discours et pratique qui assure la survie du modèle d’organisation. / This research takes the literature on management tools (Moisdon et al., 1997 ; Hatchuel et Weil, 1992 ; David, 1996, 1998) as a starting point. I focus on the co-evolution of a management practice in-use (Jarzabkowski, 2004), here Knowledge Management (KM) and an organisation. My research deals with the question « How can we do KM ? ». This refers to the different approaches for managing knowledge as well as to the different reasons that lead an organisation to adopt KM practices and tools. A multi-level analysis, combining the institutional, organisational and inter-individual contexts, is carried out. This framework calls upon various theories: institutionalism, management tools, managerial theories of the multinational corporation, social regulation (Reynaud, 1989), thus broadening our understanding of the dynamics of a management practice in-use within an organisation. The concept of emplotment (Ricoeur, 1983) is used to study the dynamics of KM within the Cement Division of the Lafarge group. The main plot - why KM? - brings forward the strategic context of the cement industry and the organisation of the technical expertise function. This plot is the starting-point for the different stories of KM in the Cement Division, which are told from different perspectives in time and space. The main results of this research show that Knowledge Management is mainly used to increase the firm’s legitimacy both towards external and internal stakeholders. KM is a tool in the hands of strong headquarters that claim to be the ultimate knowledge owner. Thus, I related the switch of KM from a perspective based on personalisation, competencies management and autonomy to a perspective focusing on codification, information management and prescription. Resistance to codification highlights the conflict between KM, set in a control mode (régulation de contrôle) and the employee’s will for autonomy (régulation autonome). The tension between these two types of regulation leads to a crisis as can be seen through the growing sense of unease among the experts. In the end however, such tensions do not interfere with the daily run of operations as KM is decoupled from ongoing activity. Thus, the story of the Cement Division is a case of strategic domination. In the absence of a joint regulation (régulation conjointe), decoupling discourse from practice allows the survival of the organizational model.
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