In antibiotic therapy design, conventional wisdom holds that higher antibiotic dosages always leads to the observation of fewer bacterial cells, resulting in a monotonic decay in cell number as a function of increasing antibiotic dose; accordingly, throughout this thesis, we will call this phenomenon a monotone dose-response profile. When we analysed the evolution of antibiotic resistance mediated by the multi-drug efflux pump AcrAB-TolC in Escherichia coli to study if such a monotone dose-response is maintained at all times, our analysis showed that higher dosages can, in fact, lead to higher bacterial loads. This is because selection for drug resistance is mediated by the duplication of the genes, AcrAB-TolC, that encode the aforementioned efflux pump. As explained in detail below, our work highlights the idea that Darwinian selection on additional copies of AcrAB-TolC is a non-linear function of antibiotic dose and that the observed transition from monotone to non-monotone dose-response is a consequence of AcrAB-TolC being strongly selected at very specific dosages. We term this phenomenon an ‘evolutionary hotspot’. Next, we extended the above experimental system to solid media to study how selection on resistance mediated by AcrAB-TolC leads to a ‘spatio-genomic patterning’ effect that we call a ‘bullseye’. Using a bespoke culture device developed as part of this PhD, we show that spatial selection on resistance also depends non-linearly on the distance of the cell from an antibiotic source, and that the non-linearity can be multi-modal as a function of distance, and therefore also of antibiotic dose. This result also contradicts the aforementioned principle that higher antibiotic dosages necessarily lead to fewer bacterial cells. Following on from this, we then studied the ability of microbial competitors for resources to modulate the antibiotic sensitivity of a particular strain of E. coli, namely Tets , using a range of multi-species experiments. We measured the sensitivity to antibiotics of Tets both with, and without, one bacterial or fungal competitor. When that competitor was equally sensitive to the antibiotic, we observed that Tets was less sensitive to it, in part due to an ‘antibiotic sinking’ effect carried out by the competitor strain. However, when the competitor was not sensitive to the antibiotic, Tets was, accordingly, more sensitive than in the absence of competition. In this latter case, the competitor seemed to reduce the growth of Tets by carbon theft as part of a phenomenon known as ‘competitive suppression’. Moreover, this ecological effect is one that synergises with the action of the antibiotic. Finally, we turned to a study of an ecological trade-off motivated by ribosome-binding antibiotics. So, by manipulating the content of ribosomal RNA in the E. coli cell, a large and essential molecule that is bound by antibiotics such as tetracycline or erythromycin, we could subsequently manipulate what is known as a metabolic trade-off between growth rate and growth yield. The latter is the number of cells produced per molecule of carbon found in the extracellular environment of the bacterial population. Using glucose as carbon source we therefore constructed an empirical fitness landscape that shows how the optimum number of ribosomal rRNA operons depends on extracellular glucose concentration. Whilst this study does not relate directly to the presence of an antibiotic, it does show that by altering the number of operons in a manner that is known to affect antibiotic susceptibility, we can also mediate important growth parameters like cell yield, aka efficiency, and growth rate.

Bakgrund: Företag söker ständigt nya sätt att designa effektivare flödeskedjor och för att säkerställa lönsamhet eftersträvas en minskning av kostnader inom produktion, transport och lager. Då lagerrelaterade kostnader står för en stor del av företags totala logistikkostnader har det kommit att stå i fokus för kostnadsminskande aktiviteter. Att minska kostnaderna relaterade till lager och samtidigt erhålla en önskad servicegrad benämns lagerstyrning. Ett sätt att uppnå bättre lagerstyrning är att lokalisera slöseri som kan finnas inom dagens styrning. Detta kan göras genom att upprätta en processkartläggning för att därigenom lokalisera och minimera eller eliminera det slöseri som identifieras genom olika förbättringsåtgärder. Syfte: Syftet med denna avhandling är att beskriva Gotlandsäggs nuvarande lagerstyrning av äggförpackningar och vilka kostnader det leder till för företaget. Därefter kommer eventuella slöserier i den nuvarande lagerstyrningen av äggförpackningar att identifieras för att sedan lägga fram förslag för hur lagerstyrningen kan förbättras med målet att minska kostnaderna för företaget samtidigt som önskad servicenivå uppnås. Metod: Studien är en kvalitativ fallstudie på företaget Gotlandsägg ABs förpackningsanläggning i Ruda. Denna har antagit en deduktiv forskningsansats med ett positivistiskt synsätt. Datainsamling har gjorts av både primärdata i form av strukturerade, semistrukturerade och ostrukturerade intervjuer med personal på Gotlandsägg samt sekundärdata som samlats in från Gotlandsäggs system, Linnéuniversitetets databas och tillgänglig litteratur. Slutsats: Studien har beskrivit Gotlandsäggs nuvarande påfyllningsprocess av äggförpackningar genom att upprätta en processkartläggning och fastställt den definierbara årliga kostnaden för lagerstyrningen. Den nuvarande styrningen innebär att förpackningar lagerhålls länge och därmed binder kapital vilket ökar lagerföringskostnaderna. Genom kartläggningen identifierades slöseri i form av en aktivitet som inte var värdeskapande, nyttjandet av ett manuellt lagersaldo, samt slöseri i form av väntan på digitalt lagersaldo och väntan på manuella beräkningar inför beordring. Gotlandsäggs onödiga lagerhållning fastställdes även som ett slöseri och orsakerna till de olika slöserierna identifierades och presenterades i olika Ishikawadiagram. Förbättringsförslagen som studien resulterade i innebar att avskaffa det manuella lagersaldot och att möjliggöra direkt tillgång av det digitala lagersaldot på förpackningsanläggningen i Ruda. Genom att investera i ett system kopplat till det digitala lagersaldot där beräkningarna inför beordring görs automatiskt skulle slöseriet i form av väntan minska. En excelmodell togs även fram som en förbättringsåtgärd till dess att en investering i ett automatiskt system kan göras. För påfyllningar rekommenderades Gotlandsägg att fortsätta beordra fulla transporter men med lägre kvantiteter för varje enskild artikel. En ABC-klassificering genomfördes därför för att underlätta styrningen genom att fokusera på de artiklar som binder mest kapital. Vidare rekommenderades tillämpningen av en högre lagerränta för att undvika onödig lagerhållning i framtiden. / Background: Companies are constantly seeking new ways to design more efficient supply chains and, to ensure profitability, seeks to reduce the costs of production, transportation and inventory. Because inventory related costs account for a large part of the company's total logistics costs, it has come to be the focus of many cost reduction activities. To reduce costs related to inventory while obtaining a desired service level is referred to as inventory control. One way to achieve better inventory control is to locate waste that may exist in the current control. This can be done by establishing a process mapping in order to identify and minimize or eliminate the waste that was identified by giving suggestions of improvement. Purpose: The purpose of this study is to describe Gotlandsägg’s current inventory control of packages for eggs and what costs it results in. Possible waste is then identified in the current inventory control of packages to further on present suggestions on how the inventory control can improve with the goal of reducing costs while still achieve a desired service level. Method: The following essay is a qualitative case study, performed on the company Gotlandsägg AB's packaging plant in Ruda. The study has adopted a deductive standpoint with a positivistic approach. The collection of data contains both primary data, which have been collected through unstructured, structured and semi-structured interviews with staff of Gotlandägg, and secondary data that have been collected from Gotlandsäggs intern systems, Linnaeus University's database and other available literature. v Conclusion: The study has described Gotlandsäggs current replenishment process of their packages for eggs by establishing a process mapping and determined the definable annual cost of inventory management. The current inventory control leads to that the packages are stored for a long time and therefore results in large amounts of tied up capital which increases inventory carrying costs. The process mapping further defined waste in a form of activity that did not create any value to the process, the use of manual inventory levels, as well as waste in the form of waiting for the digital inventory balance and manual calculations to be made before ordering could be performed. Gotlandsägg’s excessive inventory was also identified as a type of waste and the reasons for the types of waste was presented in different Ishikawa-diagrams. The suggestions for improvements concluded to eliminate the manual inventory levels and to allow direct access of the digital inventory levels at the packaging plant in Ruda. By investing in a system that is linked to the inventory levels, where calculations for ordering are made automatically, the waste of waiting could be minimized. An excel model was developed as an improvement until investments in an automated system can be made. For the refills of items, its recommended to control the packaging types in different ways but that all articles should be ordered in minimum order quantity as far as possible. As regarding transport, Gotlandsägg should continue to order full transports but with lower quantities of each article. An ABC-classification was therefore carried out to facilitate the control and to focus on the articles responsible for the most tied up capital. It was also recommended to adopt a higher inventory rate to avoid excessive inventory in the future.

No description available.

Thesis advisor: Elizabeth Kensinger / Thesis advisor: Katherine Mickley / Current research suggests that viewing complex scenes composed of a background and a negative, centralized image results in an emotion-induced memory trade-off. This trade-off is often characterized by high rates of memory accuracy for negative central images at the expense of a neutral background. In the present study, I explored whether the same trade-off effect is present for positive emotional stimuli. Therefore, when viewing complex scenes composed of a background and a positive central image, do people tend to remember the positive image more than they do the background? I examined two related research questions: (1) will positive scene components elicit an emotional memory trade-off effect? and (2) how does the passage of time, with and without sleep, influence positive scene components in comparison to negative scene components? Participants were separated into a sleep group and a wake group. The experiment consisted of two parts: the first was a viewing of 90 compound scenes and the second included a memory recognition test. Although the trade-off effect was present for negative valence items as well as positive objects, no main group effect was found. In other words, the emotional memory trade-off effect was not enhanced with sleep. / Thesis (BA) — Boston College, 2010. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Psychology Honors Program. / Discipline: Psychology.

<p>I rinnande vatten, så som bäckar och åar, har Gammarus pulex en viktig ställning i näringsväven. Arten bidrar till att bryta ner organiskt material och göra energin i detta tillgänglig för andra organismer. G. pulex är dessutom en viktig föda för ett stort antal predatorer. Flera studier visar att G. pulex reagerar på olika temperaturer. Tillväxthastighet, livslängd, reproduktion, aktivitet och syreförbrukning är exempel på karaktärer som påverkas av temperaturen. Ingen studie har tidigare behandlat om anläggningen av exokutikula påverkas av temperaturen. En höjd temperatur ökar tillväxthastigheten och detta skulle kunna ge minskade resurser till generering av exokutikula, såkallad ”trade off”. Min studie syftar till att undersöka hur G. pulex tvingas fördela sina resurser mellan tillväxt och exokutikulans tjocklek i förhållande till förändrade temperaturförhållande. Till undersökningen användes 80 djur från två naturliga system med en genomsnittlig temperaturskillnad på 1,9ºC. Säsongsvariation mellan höst och vinter studerades utifrån samma lokaler. Exokutikulans tjocklek mättes och kroppslängden användes som storleksreferens. Statistisk analys gjordes av kvoten exokutikulatjocklek/kroppslängd och ingen signifikant skillnad hittades mellan de olika grupperna. Denna studie visar att ingen ”trade off” finns mellan exokutikulans tjocklek och tillväxt hos G. pulex, varken i de två systemen, eller p.g.a. säsongsvariation, höst och vinter. Detta kan bero på Amfipoders möjligheter att återanvända kalcium för uppbyggnad av en ny exokutikula samt eventuell god tillgång på resurser. Dessutom ger en höjd metabolism vid ökad temperatur ökade möjligheter till en snabb generering av en ny exokutikula. Vidare studier bör göras i både naturliga och artificiella miljöer för att vidare undersöka en eventuell ”trade off” mellan tillväxt och exokutikula.</p>

I rinnande vatten, så som bäckar och åar, har Gammarus pulex en viktig ställning i näringsväven. Arten bidrar till att bryta ner organiskt material och göra energin i detta tillgänglig för andra organismer. G. pulex är dessutom en viktig föda för ett stort antal predatorer. Flera studier visar att G. pulex reagerar på olika temperaturer. Tillväxthastighet, livslängd, reproduktion, aktivitet och syreförbrukning är exempel på karaktärer som påverkas av temperaturen. Ingen studie har tidigare behandlat om anläggningen av exokutikula påverkas av temperaturen. En höjd temperatur ökar tillväxthastigheten och detta skulle kunna ge minskade resurser till generering av exokutikula, såkallad ”trade off”. Min studie syftar till att undersöka hur G. pulex tvingas fördela sina resurser mellan tillväxt och exokutikulans tjocklek i förhållande till förändrade temperaturförhållande. Till undersökningen användes 80 djur från två naturliga system med en genomsnittlig temperaturskillnad på 1,9ºC. Säsongsvariation mellan höst och vinter studerades utifrån samma lokaler. Exokutikulans tjocklek mättes och kroppslängden användes som storleksreferens. Statistisk analys gjordes av kvoten exokutikulatjocklek/kroppslängd och ingen signifikant skillnad hittades mellan de olika grupperna. Denna studie visar att ingen ”trade off” finns mellan exokutikulans tjocklek och tillväxt hos G. pulex, varken i de två systemen, eller p.g.a. säsongsvariation, höst och vinter. Detta kan bero på Amfipoders möjligheter att återanvända kalcium för uppbyggnad av en ny exokutikula samt eventuell god tillgång på resurser. Dessutom ger en höjd metabolism vid ökad temperatur ökade möjligheter till en snabb generering av en ny exokutikula. Vidare studier bör göras i både naturliga och artificiella miljöer för att vidare undersöka en eventuell ”trade off” mellan tillväxt och exokutikula.

I studied nest characteristics, breeding dispersal, and nest defence behaviour of Northern Flickers (<i>Colaptes auratus</i>, hereafter flickers) in central interior British Columbia with respect to nest predation. My research focused on three questions: (1) Are there nest characteristics associated with the risk of nest predation and nest loss to European Starlings (<i>Sturnus vulgaris</i>)? (2) Does nest predation influence breeding dispersal? (3) Do parental attributes influence nest defence behaviour? <p> An examination of flicker nest-site characteristics at five spatial scales revealed that nests were safer from mammalian predators (N=81) when they were higher, concealed by vegetation, farther from continuous coniferous forest blocks, and contained fewer conifers within the nesting clump. Proximity to conifers increased predation risk, but nests safe from competitors (N=18) were closer to coniferous forest blocks and contained a higher percentage of conifers in the nesting clump. Flickers face a trade-off between being safe from predators and safe from competitors. <p> Nesting success did not influence between-year breeding dispersal by 159 male or 76 female flickers. Because nests and forest clumps were not predictably safe from predators, benefits of dispersing likely outweigh costs. Other factors such as mate-switching, nest ectoparasites, and a fluctuating food source may play larger roles in dispersal than nest predation. Within years, 73% of pairs switched nest sites after their first attempt failed due to predation (N=37); however, there was no reproductive advantage for these pairs compared to pairs that remained at their original nest. Stressful encounters with predators involving nest defence may trigger dispersal, although it seems to offer no greater nest success. Of 24 flicker pairs presented with a control model before egg-laying, 3 pairs abandoned their nest, whereas 4 out of 24 pairs presented with a squirrel model abandoned their nest. This suggests that a one-time encounter with a nest predator is not a sufficient deterrent against continued nesting. Rather, costs of finding and excavating or renovating a new cavity may cause individuals to tolerate some risk in nesting at a location with an active predator. <p> In experimental trials (N=94), intensity of nest defence behaviour against a model predator was not related to the sex, age, body size, and body condition of the defending adult(s). The sexes may have behaved similarly because they are similar in size and have similar survival patterns. Costs and benefits of nest defence for flickers of different ages may also be equal because flickers are relatively short-lived and their survival rate is not linked with age. Brood size of the defending adult was also unrelated to the intensity of nest defence. If flickers have adjusted their clutch size in relation to the number of young for which they can optimally provide care, then no effects of brood size on nest defence behaviour should be recorded, as was the case here.</p>

Employing a design solution can satisfy some requirements while having negative side-effects on some other software requirements and project objectives. Ultimately, selecting a design solution among multiple options involves making trade-offs among competing requirements. These trade-offs, especially at the early stages of software development, are often hard to identify or quantify, and can be subjective. Security is one critical requirement among many, which can cause critical trade-offs and severe costs. Damages from security attacks can be overwhelming and the costs increase every year. The threat of vulnerabilities and their exploitation by potential adversaries calls for careful analysis of security risks and trade-offs that security solutions impose, from the viewpoints of both defenders and attackers. Since software developers and analysts are usually not security experts, detecting potential threats within software systems can be problematic. Even when threats are known, the risk factors, either the probability of a successful attack or the resulting damage of a successful attack, are not always known or numerically measurable. In this situation, selecting proper security solutions can be challenging, when mitigating impacts and side-effects of solutions are often not quantifiable. This thesis addresses such challenges in identifying and making trade-offs among security and other system requirements and stakeholders' goals. This work introduces a framework for identifying and modeling security risks and requirements trade-offs. The central idea in this thesis is analyzing security requirements on the basis of predicting software vulnerabilities, weaknesses or flaws that can be exploited to break into the system. Vulnerabilities and exploitation scenarios are specified within goal-oriented requirements models of the system. This approach enables analysis of vulnerability exploitations and their impacts on the running system. The structure of goal-oriented security requirements models enables tracing the ultimate impacts of the exploitations on high-level goals of stakeholders and design objectives. In order to evaluate the risk of vulnerabilities, this framework intertwines the Common Vulnerability Scoring System (CVSS) with security requirements risk assessment. The proposed framework provides a decision aid method that takes into the account risks, competing requirements, security solutions, their impacts on risks, and their side-effects on other requirements, to aid decision makers to select a solution among alternative security solutions. The proposed decision analysis method helps analysts to make requirements trade-offs systematically, in the absence of quantitative data, or when a mixture of both quantitative and qualitative data are available.

Employing a design solution can satisfy some requirements while having negative side-effects on some other software requirements and project objectives. Ultimately, selecting a design solution among multiple options involves making trade-offs among competing requirements. These trade-offs, especially at the early stages of software development, are often hard to identify or quantify, and can be subjective. Security is one critical requirement among many, which can cause critical trade-offs and severe costs. Damages from security attacks can be overwhelming and the costs increase every year. The threat of vulnerabilities and their exploitation by potential adversaries calls for careful analysis of security risks and trade-offs that security solutions impose, from the viewpoints of both defenders and attackers. Since software developers and analysts are usually not security experts, detecting potential threats within software systems can be problematic. Even when threats are known, the risk factors, either the probability of a successful attack or the resulting damage of a successful attack, are not always known or numerically measurable. In this situation, selecting proper security solutions can be challenging, when mitigating impacts and side-effects of solutions are often not quantifiable. This thesis addresses such challenges in identifying and making trade-offs among security and other system requirements and stakeholders' goals. This work introduces a framework for identifying and modeling security risks and requirements trade-offs. The central idea in this thesis is analyzing security requirements on the basis of predicting software vulnerabilities, weaknesses or flaws that can be exploited to break into the system. Vulnerabilities and exploitation scenarios are specified within goal-oriented requirements models of the system. This approach enables analysis of vulnerability exploitations and their impacts on the running system. The structure of goal-oriented security requirements models enables tracing the ultimate impacts of the exploitations on high-level goals of stakeholders and design objectives. In order to evaluate the risk of vulnerabilities, this framework intertwines the Common Vulnerability Scoring System (CVSS) with security requirements risk assessment. The proposed framework provides a decision aid method that takes into the account risks, competing requirements, security solutions, their impacts on risks, and their side-effects on other requirements, to aid decision makers to select a solution among alternative security solutions. The proposed decision analysis method helps analysts to make requirements trade-offs systematically, in the absence of quantitative data, or when a mixture of both quantitative and qualitative data are available.

Syftet med denna studie är att utifrån teoretiska ansatser och tidigare forskning som rör kapitalstruktur, visa om de tre valda finansiella företagsegenskaperna förklarar kapitalstrukturen i små onoterade svenska företag. De teoretiska ansatser som testas är främst pecking-order och trade-off. En kvantitativ ansats har använts i uppsatsen där sex hypoteser bildats utifrån de teoretiska ansatserna. Uppsatsen är av positivistisk karaktär och har en deduktiv ansats. Analysen baseras på både enkla och multipla regressionsanalyser av nyckeltal som beräknades från material som hämtats i årsredovisningar från de 220 utvalda företagen. Samtliga av de utvalda företagen slumpades fram från en lista över små företag som ej är registrerade på någon börslista. Resultaten indikerar att de teoretiska ansatserna som utformats för att förklara kapitalstrukturen i stora företag inte förklarar densamma för svenska små företag. Det finns samband som stödjer de teoretiska ansatserna och hypoteserna men förklaringsgraderna för de finansiella företagsegenskaperna i relation till skuldsättningen i företagen påvisar att sambanden är svaga. / The purpose of this study is to use theoretical approaches and previous research related to capital structure to show if the three selected firm characteristics explain the capital structure of small unlisted Swedish firms. The theories that are tested are primarily Pecking-order theory and the Trade-off theory. A quantitative approach has been used in our thesis where six hypotheses are formed according to the theoretical approaches. The thesis has a positivistic research philosophy and a deductive approach. The analysis is based on both simple and multiple regression analyzes that were calculated from the material obtained in the annual reports of the 220 selected firms. All of the selected firms were randomly chosen from a list of small businesses that are not listed on any exchange list. The results indicate that the theoretical approaches developed to describe the choice of capital structure of large firms do not explain the same for Swedish small businesses. However, there are relationships that support the theoretical approaches and hypotheses, but the coefficient of determination for the explanatory firm characteristics related to small firms leverage indicate that the correlation is weak. The study provides a snapshot of the relationship between leverage and the selected explanatory firm characteristics: asset structure, profitability and growth, based on firms´ annual reports for the year 2011.