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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Moving Beyond Trade-offs : Exploring the linkage between Financial Return and Social Impact

Appelqvist, David, Paulsson, Maja January 2020 (has links)
Background:  A growing momentum around the potential of impact investing to contribute to development in both environmental and social sustainability has challenged the way business is operating, offering solutions for both the people and planet. Previous studies have claimed that trade-offs between purpose and profit are inevitable in order to successfully achieve sustainability goals, which requires practitioners in the financial discipline to invent new investment approaches to manage dual outcomes. Here, it becomes evident to move beyond trade-offs to avoid that one goal outperforms the other, considered as a vital question to address towards a new investment paradigm.  Purpose:  This study aims to explore the nexus between social impact and financial return, and thus understand the different factors that enable managers in the impact investing industry to successfully manage the trade-offs between pursuing dual values.     Method:  An interpretivist approach is followed throughout the study with an exploratory nature that is used to analyze two company cases. In total, two participants were interviewed through qualitative and semi-structured questions; two managers in the impact investing field.   Conclusion:  The findings reveal the interconnection of impact measurement, values and impact management. The authors have derived a model that graphically represents the Impact-Return Nexus Model (IRNM) which enhances the impact awareness and long-term value creation. The result of this study shows how the synergy between social impact and financial return will improve the performance on both sides. Accordingly, the cases present that a nuanced impact-approach tends to scale both impact and profits.
52

Dynamics of Hydro-power Development in Nepal: Water-Energy-Food Security Prospect

Neupane, Jaya Lal January 2022 (has links)
This thesis concerns with water, energy, and food (WEF) security in Nepal in relation to hydropower development. Hydropower is challenging to WEF security in three ways: First, the focus is only on energy generation which overlooks the impacts on land, forest, water and biodiversity. Second, the hydropowerprojects are being built in the tributaries of transboundary rivers where local, national and international interests and priorities intersect because these rivers are sources of the economy; water, energy, food commodities; and other ecosystems services. Third, discourses on renewable energy, sustainable development and climate change portray hydropower as a promising renewable energy source as other renewable energy sources hold very less potential in Nepal. In this context, this thesis evaluates if the benefit-sharing approach can be a solution to overcome problems related to the implementation of hydropower which challenges WEF security. Therefore, the study adoptsWEF Nexus Framework and Benefit-sharing Framework to evaluate the challenges and possibilities for rising WEF security minimizing the hydropower-induced trade-offs. The study finds hydropower development in Nepal is rapid and haphazard which merely conceives trade-offs between energy production and other benefits. But benefit-sharing practice, though it is still in its nascent phase, has positively impacted WEF security primarily at the local level, mainly by providing irrigation and drinking water facilities, rural electrification, and agriculture-related livelihood training and support. However, a well-planned benefit-sharing approach as an integral part of hydropower development is lacking which foils equitable distribution of benefits among stakeholders across all levels and smooth implementation o f hydropower projects to enhance the sustainability of hydropower.
53

Does Geographic Variation in Thermal Tolerance in Daphnia Represent Trade-Offs or Conditional Neutrality?

Coggins, B. L., Pearson, A. C., Yampolsky, Lev Y. 01 May 2021 (has links)
Geographic variation in thermal tolerance in Daphnia seems to represent genetic load at the loci specifically responsible for heat tolerance resulting from conditional neutrality. We see no evidence of trade-offs between fitness-related traits at 25 °C vs. 10 °C or between two algal diets across Daphnia magna clones from a variety of locations representing the opposite ends of the distribution of long-term heat tolerance. Likewise, we found no evidence of within-environment trade-offs between heat tolerance and fitness-related traits in any of the environments. Neither short-term and long-term heat tolerance shows any consistent relationship with lipid fluorescence polarization and lipid peroxidation across clones or environments. Pervasive positive correlations between fitness-related traits indicate differences in genetic load rather than trade-off based local adaptation or thermal specialization. For heat tolerance such differences may be caused by either relaxation of stabilizing selection due to lower exposure to high temperature extremes, i.e., conditional neutrality, or by small effective population size followed by the recent range expansion.
54

The Relations Among Cultural Values, Ethnicity, And Job Choice Trade-off Preferences

Isenhour, Linda 01 January 2006 (has links)
Researchers in human resource management (HRM) have long been concerned with the attraction and retention of organizational members (Breaugh, 1992; Rynes, 1991; Vroom, 1966). However, as the U.S. work force has become more diverse (U.S. Census Bureau, 2000), the need to consider how issues of cultural diversity are related to the recruitment process has become increasingly important. For example, although past research has investigated relations among individuals' values, personality, and job choice preferences, no research has examined the job choice trade-off preferences of culturally diverse individuals. Moreover, researchers have not examined explicit job choice trade-off preferences involving job and organizational factors, even though expectancy theory-based models of recruitment implicitly suggest that individuals make trade-offs among valent job and organizational factors. Therefore, the purpose of the current research was to examine the relations among individuals' (a) cultural values (power distance, Protestant Ethic-earnings, Protestant Ethic-upward striving), (b) ethnicity (European-American, Hispanic-American), and (c) their job choice trade-off preferences for organizational prestige over pay using Thurstone's (1927, 1931) law of comparative judgment method. Study 1 served as a pilot of the procedure and measures. Based on the results of Study 1, changes were made to improve reliability of measures prior to Study 2. Study 2 tested hypothesized relations among cultural values, ethnicity, and job choice trade-off preferences for organizational prestige over pay. Results from Study 2 showed that power distance cultural values were related positively to job choice trade-off preferences for organizational prestige over pay and that Protestant Ethic-earnings cultural values were related negatively to job choice trade-off preferences for organizational prestige over pay. In addition, Hispanic-Americans were more likely than European-Americans to prefer job choice trade-offs for organizational prestige over pay. However, Protestant Ethic-upward striving cultural values were unrelated to job choice trade-off preferences for organizational prestige over pay. Moreover, ethnicity was unrelated to power distance cultural values, Protestant Ethic-earning cultural values, or Protestant Ethic-upward striving cultural values. Study results suggest that including cultural values and ethnicity in future recruitment research can enhance the understanding of individuals' job choice preferences and provide practitioners with information to attract multicultural job applicants.
55

THE COST OF HORMESIS / TRADE-OFFS IN AN ENERGETICALLY CONSTRAINED ENVIRONMENT: EMBRYONIC DEVELOPMENT OF THE LAKE WHITEFISH (COREGONUS CLUPEAFORMIS)

Mitz, Charles W. January 2016 (has links)
L'exposition à des niveaux faibles de radiation ionisante est connue pour déclencher une réponse adaptative qui inclut la stimulation immunitaire et l'augmentation des effets protecteurs à long terme incluant l’amélioration de la détection et la réparation de dégâts causés à l’ADN, la croissance renforcée et la longévité. Tandis que les aspects hormetique de la réponse adaptative augmentent clairement la santé physique en présence de stress environnementaux, ils doivent la diminuer dans des conditions environnementales normales parce que les mécanismes biologiques responsables ne sont pas maintenus dans un état amélioré, mais exigent plutôt une certaine forme d'exposition sensibilisante. Il a été suggéré que la stimulation de la réponse adaptative pourrait être métaboliquement coûteuse cependant aucune mesure directe du coût métabolique de la croissance stimulée de radiation a été précédemment essayée. Cette thèse a évalué si la croissance stimulée de radiation du grand corégone (Coregonus clupeaformis) est accompagnée par un compromis dans l'efficacité métabolique ou par une augmentation durable de demandes énergiques. L'exposition à un régime fractionné de radiation ionisante d'une source de 137Cs s’est avéré stimuler considérablement la croissance dans des embryons du grand corégone comparés aux contrôles avec une augmentation correspondante de la consommation de jaune. Cependant, les mesures d'efficacité métabolique utilisant une série de temps de poids secs non préservés ont montré que la croissance stimulée était non-accompagnée par une réduction de l'efficacité métabolique. Une température moyenne exponentiellement transformée a été utilisée comme un point de référence quantitative pour évaluer la vulnérabilité du développement des embryons du grand corégone à la disparité phénologique. Le temps d’éclosion différait des prédictions de références sous des régimes thermiques asymétriquement variables. Les écarts ont été attribués aux embryons grandissant à dans un stade plus avancée de développement sous des températures basses. Le terme heterograde est proposé pour décrire la dépendance thermique dans l'étape d’éclosion qui peut avoir évolué comme un mécanisme pour synchroniser l’éclosion de larves viables pour l'augmentation de la densité de zooplancton qui accompagne le débâcle printanière Un modèle de prédiction incorporant l’éclosion heterograde a permis une amélioration significative dans l’exactitude des prédictions comparé aux modèles précédents. L'efficacité énergique a une importance particulière pour le grand corégone comme il a une des périodes d'incubation naturelles les plus longues pour un poisson d'eau douce, avec des températures d'incubation les plus basses et avec des œufs seulement 10 % de la taille de la plupart des salmonidés non-coregonine. L'évolution de mécanismes pour synchroniser l’éclosion au démantèlement de couverture de glace hivernale met en évidence la vulnérabilité du grand corégone à la disparité phénologique et ce par le développement accéléré qui cause l’éclosion asynchrone des embryons avec le démantèlement de la couverture de glace d'hiver ou par une augmentation durable de demandes énergiques qui augmentent leur vulnérabilité à la famine. L'absence de compromis mesurable dans l'efficacité métabolique indique ce dernier comme un coût général plausible de hormesis. / Exposure to low levels of ionizing radiation is known to trigger an adaptive response that includes immune stimulation and the up-regulation of long-lasting protective effects including improved detection and repair of DNA damage, enhanced growth, and longevity. While the hormetic aspects of the adaptive response clearly increase fitness in the presence of environmental stresses, they must decrease fitness under normal environmental conditions because the responsible biological mechanisms are not maintained in an upregulated state but rather require some form of sensitizing exposure. It has been suggested that stimulation of the adaptive response could be metabolically costly however no direct measurement of the metabolic cost of radiation stimulated growth has been previously attempted. This thesis assessed whether radiation-stimulated growth in the lake whitefish (Coregonus clupeaformis) is accompanied by a trade-off in metabolic efficiency, or by a sustained increase in energetic demands. Exposure to a fractionated regime of ionizing radiation from a 137Cs source was found to significantly stimulate growth in lake whitefish embryos compared to controls with a corresponding increase in yolk consumption. However, measurements of metabolic efficiency using a time series of unpreserved dry weights showed that the stimulated growth was unaccompanied by a reduction in metabolic efficiency. An exponentially transformed mean temperature was used as a quantitative baseline to assess the vulnerability of developing whitefish embryos to phenological mismatch. Hatch timing was found to deviate from baseline predictions under asymmetrically variable thermal regimes. The deviations were attributed to the embryos growing to a more advanced stage of development at low temperatures. The term heterograde is proposed to describe the thermal dependency of hatching stage which may have evolved as a mechanism to synchronize the hatching of viable larvae to the increase of zooplankton density that accompanies spring break-up. A predictive model incorporating heterograde hatching yielded a significant improvement in predictive accuracy over previous models. Energetic efficiency is of particular importance to the lake whitefish as it has one of the longest natural incubation periods of any freshwater fish, at some of the lowest incubation temperatures, and with eggs only 10% the size of most non-coregonine salmonids. The evolution of mechanisms to synchronize hatching to the break-up of winter ice cover highlights the vulnerability of the lake whitefish to phenological mismatch whether through accelerated development that causes embryos to hatch asynchronously with the break-up of winter ice cover, or through a sustained increase in energetic demands that increases their vulnerability to starvation. The absence of any measurable trade-off in metabolic efficiency points to the latter as a plausible general cost of hormesis. / Dissertation / Doctor of Philosophy (PhD)
56

Security and Performance Engineering of Scalable Cognitive Radio Networks. Sensing, Performance and Security Modelling and Analysis of ’Optimal’ Trade-offs for Detection of Attacks and Congestion Control in Scalable Cognitive Radio Networks

Chuku, Ejike E. January 2019 (has links)
A Cognitive Radio Network (CRN) is a technology that allows unlicensed users to utilise licensed spectrum by detecting an idle band through sensing. How- ever, most research studies on CRNs have been carried out without considering the impact of sensing on the performance and security of CRNs. Sensing is essential for secondary users (SUs) to get hold of free band without interfering with the signal generated by primary users (PUs). However, excessive sensing time for the detection of free spectrum for SUs as well as extended periods of CRNs in an insecure state have adverse effects on network performance. Moreover, a CRN is very vulnerable to attacks as a result of its wireless nature and other unique characteristics such as spectrum sensing and sharing. These attacks may attempt to eavesdrop or modify the contents of packets being transmitted and they could also deny legitimate users the opportunity to use the band, leading to underutilization of the spectrum space. In this context, it is often challenging to differentiate between networks under Denial of Service (DoS) attacks from those networks experiencing congestion. This thesis employs a novel Stochastic Activity Network (SAN) model as an effective analytic tool to represent and study sensing vs performance vs security trade-offs in CRNs. Specifically, an investigation is carried out focusing on sensing vs security vs performance trade-offs, leading to the optimization of the spectrum band’s usage. Moreover, consideration is given either when a CRN experiencing congestion and or it is under attack. Consequently, the data delivery ratio (PDR) is employed to determine if the network is under DoS attack or experiencing congestion. In this context, packet loss probability, queue length and throughput of the transmitter are often used to measure the PDR with reference to interarrival times of PUs. Furthermore, this thesis takes into consideration the impact of scalability on the performance of the CRN. Due to the unpredictable nature of PUsactivities on the spectrum, it is imperative for SUs to swiftly utilize the band as soon as it becomes available. Unfortunately, the CRN models proposed in literature are static and unable to respond effectively to changes in service demands. To this end, a numerical simulation experiment is carried out to determine the impact of scalability towards the enhancement of nodal CRN sensing, security and performance. Atthe instant the band becomes idle and there are requests by SUs waiting for encryption and transmission, additional resources are dynamically released in order to largely utilize the spectrum space before the reappearance of PUs. These additional resources make the same service provision, such as encryption and intrusion detection, as the initial resources. To this end,SAN model is proposed in order to investigate the impact of scalability on the performance of CRN. Typical numerical simulation experiments are carried out, based on the application of the Mobius Petri Net Package to determine the performance of scalable CRNs (SCRNs) in comparison with unscalable CRNs (UCRNs) and associated interpretations are made.
57

Mechanisms and Evolution of Iridescent Feather Colors in Birds

Eliason, Chad M. 11 September 2014 (has links)
No description available.
58

The Stability of Lytic Sulfolobus Viruses

Gazi, Khaled S. January 2017 (has links)
No description available.
59

Residential Location Decisions: Heterogeneity and the Trade-off between Location and Housing Quality

Kim, Moon-Jeong 25 August 2010 (has links)
No description available.
60

Two Issues in Premise Plumbing: Contamination Intrusion at Service Line and Choosing Alternative Plumbing Material

Lee, Juneseok 01 May 2008 (has links)
Worldwide water distribution infrastructure system is old and deteriorating. A water system with its myriad appurtenances (including pumps and valves and tanks) is susceptible to hydraulic transients resulting in high and low pressure waves alternatively passing through the network. While both low and high pressure events structurally tax the already weak system, there is copious evidence indicating intrusion of contaminants into the drinking water pipes from the pipe's exterior environment due to low pressure events associated with water hammer phenomenon. These contaminants enter into the drinking water as the home plumbing system is a passive recipient from the water main. While the major (municipal) system is readily recognized as a vast infrastructure system of nearly 1,409,800 km of piping within the United States, the minor (plumbing) system that is at least 5 to 10 times larger is generally not well analyzed. In this study, an experimental plumbing rig was designed and implemented that replicates the range of pressures encountered in actual minor water distribution systems. This research addresses how a pressure transient triggered within a house and from municipal systems can impact the service line with a possible suction effect. Experimental results on low pressure events and the accompanying numerical modeling showed good agreement. The experiment also enabled visualization of the various pressure transient phenomena. It is demonstrated that hydraulic transients triggered from water mains result in low pressures events (up to -10 psig) in service lines which can allow possible intrusion of microbial and chemical contaminants at the service line. Structural integrity of service line and hydraulic integrity at water mains should be maintained to minimize any public health risks. In the USA, about 90% of residential drinking water plumbing systems use copper pipes. Pinhole leaks in copper plumbing pipes have become a nationwide concern because these leaks cause property damage, lower property values, and result in possibility of adversely affecting homeowners' insurance coverage. In addition, resulting mold damage may cause health concerns. This research also addresses the concerns of the affected homeowners by enabling them to decide on whether to continue to repair or replace their plumbing system, the factors to be considered in a replacement decision, and the type of material to use for replacement. Plastic pipes such as PEX (cross-linked polyethylene), CPVC (Chlorinated Polyvinyl Chloride), and copper are considered in present analysis. Other alternatives include an epoxy coating technique on the existing piping systems, without the need to tear into walls. Multiple attributes of a plumbing system including cost (material plus labor charges), taste and odor impacts, potential for corrosion, longevity of the pipe system, fire retardance, convenience of installation or replacement, plumber or general contractor's opinions or expertise, and proven record in the market are considered. Attributes and material rankings are formalized within the framework of the preference elicitation tools namely AHP (Analytical Hierarchical Process). Surveys are conducted with selected homeowners in pinhole leak prone area in Southeastern US Community to observe their revealed and stated preferences. Participants' overall preference tradeoffs are reported in addition to comparing their revealed and stated preferences. Health effects, taste and odor of water turned out to be the most important factors from the survey. In real life, however, homeowners were not well aware of these safety issues related with plumbing materials. It is recommended that water professionals should work on bridging the gap between public perception and research results related to major and minor systems. / Ph. D.

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