Thesis (MPA) --University of Limpopo, 2010 / Rural households have always faced a variety of risks which rendered them vulnerable to poverty; hence, they have continuously adopted different risk-spreading strategies aimed at reducing and/or de-concentrating the risks that they face. However, there is always a chance that risk-spreading strategies adopted by rural households could intensify or increase the levels of vulnerability to poverty, because most of them are too informal and ineffective. The study examines different risks that households in the rural areas face, including their implication for levels of vulnerability to poverty. The effects of risk-spreading strategies on household level of vulnerability are analysed using a sample of 100 households from Tsianda village. The survey results reflect that a variety of risks faced in the village have a cumulative effect on households’ vulnerability to poverty. However, the risk-spreading strategies appear to be more helpful for the better-off households than for the poor, because the former experience short-term risks whereas the latter face apparently multiple perpetual risks. The village’s political, social, economic, cultural, institutional, technological and environmental contexts seem to perpetuate the status quo against the efforts of the poor households. The study concludes that the political,social, economic, cultural, institutional, technological and environmental contexts in the rural area have a huge impact on the concentration of risks that households face, the risk-spreading that they adopt and also their level of vulnerability to poverty. Hence, the poorer households’ risk-spreading strategies are not effective to reduce and de-concentrate the risks; moreover theyintroduce them to new risks and high level of vulnerability to poverty. / University of Limpopo

<p>Water is the most consumed foodstuff around the world. Therefore it is very important to analyze possible faecal contamination of water, and Enterococci are an indicator for that. They are also used as an indicator for possible faecal contamination in food. Normally you find Enterococci in the intestines of humans and animals, but Enterococci can also give infections like urinary tract infection.</p><p>In this study, varying number of colonies and colours of Enterococci on different media were evaluated. The purpose was to investigate if three different methods would give the same numbers of colonies. Another interesting perspective was to investigate if one medium could be used for two methods. Membrane filter techniques and surface spreading techniques were used to detect Enterococci. These methods were compared with a most probable number method.</p><p>None of the strains showed an optimal result on all media, however one medium, ChromoCult, showed good results for all investigated strains.</p>

<p>Integrins are a protein family of cell surface receptors, expressed in all cell types in the human body, except the red blood cells. Besides their importance in mediating physical connections with the surrounding environment, the integrin family members are also vital signalling mediators. They have no intrinsic kinase activity; instead the signals are transduced through conformational changes. </p><p>In this thesis, work is presented which is focused on molecular mechanisms of integrin signal transduction. The signal transduction was first studied from a structural point of view, determining the transmembrane domain borders of a few selected integrin family members and ruling out a signalling model involving a “piston-like” movement. </p><p>Then, downstream signalling events involved in the beta1 integrin-induced activation of Akt via the PI3kinase family were characterized. Our results identify a novel pathway for PI3K/Akt activation by beta1 integrins, which is independent of focal adhesion kinase (FAK), Src and EGF receptor. Furthermore, both beta1 integrins and EGF receptors induced phosphorylation of Akt at the regulatory sites Thr308 and Ser473, but only EGF receptor stimulation induced tyrosine phosphorylation of Akt.</p><p>Finally, signals from beta1 integrins underlying the morphologic changes during cell spreading were studied. A rapid integrin-induced cell spreading dependent on actin polymerisation was observed by using total internal reflection fluorescence (TIRF) microscopy. This integrin-induced actin polymerisation was shown to be dependent on PI3K p110alpha catalytic subunit and to involve the conserved Lys756 in the beta1-integrin membrane proximal part.</p>

A new method is proposed for correctly modeling the long range interaction between a fluid and a bounding wall in atomistic simulations. This method incorporates the molecular structure of the solid substrate while allowing for a finite interaction cutoff by making a proper estimation of long range correction for the fluid-wall interaction. The method is then applied to a molecular dynamic simulation of a spreading droplet. Conparison to simulations using several other previously used methods shows that the long range correction can be significant in some circumstances. / Singapore-MIT Alliance (SMA)

In this thesis, the properties of nonlinear disordered one dimensional lattices is investigated. Part I gives an introduction to the phenomenon of Anderson Localization, the Discrete Nonlinear Schroedinger Equation and its properties as well as the generalization of this model by introducing the nonlinear index α. In Part II, the spreading behavior of initially localized states in large, disordered chains due to nonlinearity is studied. Therefore, different methods to measure localization are discussed and the structural entropy as a measure for the peak structure of probability distributions is introduced. Finally, the spreading exponent for several nonlinear indices is determined numerically and compared with analytical approximations. Part III deals with the thermalization in short disordered chains. First, the term thermalization and its application to the system in use is explained. Then, results of numerical simulations on this topic are presented where the focus lies especially on the energy dependence of the thermalization properties. A connection with so-called breathers is drawn. / In dieser Arbeit wird das Verhalten nichtlinearer Ketten mit Zufallspotential untersucht. Teil I enthaelt eine Einfuehrung in das Phaenomen der Anderson Lokalisierung, die Diskrete Nichtlineare Schroedinger Gleichung und ihren Eigenschaften sowie die verwendete Verallgemeinerung des Modells durch Einfuehrung eines Nichtlinearitaets-Indizes α. In Teil II wird das Ausbreitungsverhalten von lokalisierten Zustaenden in langen, ungeordneten Ketten durch die Nichtlinearitaet untersucht. Dazu werden zuerst verschiedene Lokalisierungsmaße besprochen und außerdem die strukturelle Entropie als Messgroeße der Peakstruktur eingefuehrt. Im Anschluss wird der Ausbreitungskoeffzient fuer verschiedene Nichtlinearitaets-Indizes bestimmt und mit analytischen Absch¨tzungen verglichen. Teil III behandelt schließlich die Thermalisierung in kurzen, ungeordneten Ketten. Dabei wird zuerst der Begriff Thermalisierung in dem verwendeten Zusammenhang erklaert. Danach erfolgt eine numerische Analyse von Thermalisierungseigenschaften lokalisierter Anfangszustaende, wobei die Energieabhaengigkeit besondere Beachtung genießt. Eine Verbindung mit sogenannten Breathers wird dargelegt.

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Integrins are a protein family of cell surface receptors, expressed in all cell types in the human body, except the red blood cells. Besides their importance in mediating physical connections with the surrounding environment, the integrin family members are also vital signalling mediators. They have no intrinsic kinase activity; instead the signals are transduced through conformational changes. In this thesis, work is presented which is focused on molecular mechanisms of integrin signal transduction. The signal transduction was first studied from a structural point of view, determining the transmembrane domain borders of a few selected integrin family members and ruling out a signalling model involving a “piston-like” movement. Then, downstream signalling events involved in the beta1 integrin-induced activation of Akt via the PI3kinase family were characterized. Our results identify a novel pathway for PI3K/Akt activation by beta1 integrins, which is independent of focal adhesion kinase (FAK), Src and EGF receptor. Furthermore, both beta1 integrins and EGF receptors induced phosphorylation of Akt at the regulatory sites Thr308 and Ser473, but only EGF receptor stimulation induced tyrosine phosphorylation of Akt. Finally, signals from beta1 integrins underlying the morphologic changes during cell spreading were studied. A rapid integrin-induced cell spreading dependent on actin polymerisation was observed by using total internal reflection fluorescence (TIRF) microscopy. This integrin-induced actin polymerisation was shown to be dependent on PI3K p110alpha catalytic subunit and to involve the conserved Lys756 in the beta1-integrin membrane proximal part.

Water is the most consumed foodstuff around the world. Therefore it is very important to analyze possible faecal contamination of water, and Enterococci are an indicator for that. They are also used as an indicator for possible faecal contamination in food. Normally you find Enterococci in the intestines of humans and animals, but Enterococci can also give infections like urinary tract infection. In this study, varying number of colonies and colours of Enterococci on different media were evaluated. The purpose was to investigate if three different methods would give the same numbers of colonies. Another interesting perspective was to investigate if one medium could be used for two methods. Membrane filter techniques and surface spreading techniques were used to detect Enterococci. These methods were compared with a most probable number method. None of the strains showed an optimal result on all media, however one medium, ChromoCult, showed good results for all investigated strains.

Smittsamma sjukdomar kostar det svenska samhället enorma summor varje år. Behandlingen av smittade patienter har tidigare uppskattats till 5-10 miljarder svenska kronor årligen. Vidare estimeras de förebyggande åtgärderna kosta samhället runt en miljard svenska kronor. Detta betyder att det finns en ekonomisk drivkraft för att reducera antalet smittade patienter inom vården, speciellt de fall som är orsakade av resistenta bakterier. Samtidigt pågår det en debatt om resistenta bakterier och antibiotikaförbrukningen i både forskning och media. Resistenta bakterier kan bli ett hot mot vår framtid om vi inte minskar antibiotikaförbrukningen och vidtar åtgärder för att förhindra smittspridning. Om antalet personer som blir smittade av resistenta bakterier kan reduceras minskar även antibiotikaförbrukningen som i sin tur leder till att färre bakterier utvecklar ett resistensmönster för antibiotika. Detta betyder att det är viktigt att studera och effektivisera hanteringen av smittsamma patienter.   För att reducera antalet smittade patienter måste förebyggande åtgärder vidtas och smittkällan måste kartläggas vid ett upptäckt fall av en smitta. Svensk sjukvård arbetar idag aktivt med smitthantering. Detta begrepp omfattar upptäckt, kontroll och spårning av smitta. Uppdragsgivaren till detta examensarbete, Cambio Healthcare Systems, saknar en fullständig bild över hur smitthanteringen egentligen går till på ett sjukhus. Deras målsättning är att utveckla ett IT-system som kan underlätta smitthanteringsprocessen. Denna studie syftar till att kartlägga informationsflödet vid smitthanteringsprocessen och identifiera de inblandade aktörernas ansvarsområden och skyldigheter enligt regelverket. Vidare syftar arbetet till att presentera åtgärdsförslag som kan minska de identifierade riskerna och effektivisera smitthanteringsprocessen av resistenta bakterier.   För att kartlägga smitthanteringsprocessen genomfördes en fallstudie av ett svenskt universitetssjukhus under våren 2013. Aktörer som studerades var det mikrobiologiska laboratoriet, vårdhygien, smittskyddsenheten, smittskyddsinstitutet samt läkare och sjuksköterskor vid två avdelningar på sjukhuset. Datainsamlingen består av intervjuer, observationer och dokument.   Resultatet av fallstudien visade att smitthanteringsprocessen är ett komplext system med ett omfattande informationsflöde. Huvudaktörerna är vårdhygien, sjukvårdspersonalen och det mikrobiologiska laboratoriet. De är viktiga eftersom deras praktiska handlande är avgörande för att smitthanteringen genomförs. Smittskyddsenheten är inblandad till viss del, men tillhör inte huvudaktörerna. Studien visade även att smittskyddsinstitutet inte hade någon framträdande roll i smitthanteringsprocessen av resistenta bakterier på sjukhuset.   Ansvarsfördelningen är till viss del styrd av smittskyddslagen och enligt denna lag har den behandlande läkaren en central roll i processen. I verkligheten är läkarens roll mindre framträdande vid smittspårningen, vanligtvis delegerar läkaren uppgifter till sjuksköterskor eller till vårdhygien. Mycket av kommunikationen mellan aktörerna är muntlig och detta innebär att ett flertal risker kan uppstå. Vid identifieringen av risker för hela processen konstaterades det att de flesta risker kan uppstå på grund av den mänskliga faktorn, ofta i kombination med användandet av ett otillräckligt datasystem. Åtgärdsförslagen för att effektivisera processen fokuserar därför på att minimera de identifierade riskerna med hjälp av framtida IT-system.   Slutsatsen av studien är att det finns ett stort behov av IT-lösningar för att effektivisera smitthanteringsprocessen av resistenta bakterier. Min rekommendation är att Cambio Healthcare Systems AB bör fokusera på att utveckla ett system för att digitalisera arkiveringen av beläggningslistorna och spåra patientflöden tillbaka i tiden i Cosmic då detta är ett starkt önskemål från kunderna. En annan viktig åtgärd är att utveckla smittspecifika checklistor som visas på datorn i samband med att läkaren får ett positivt provsvar. Slutligen rekommenderar jag Cambio Healthcare Systems AB att utveckla ett smittlarm som kan integreras med deras befintliga whiteboardtavla som nyligen lanserades. / Infectious diseases are a major cost item for the Swedish society. The treatment of infected patients has previously been estimated to 5-10 billion SEK annually and preventive actions cost the Swedish society around one billion SEK every year. Therefore, there are strong economic incentives to reduce the number of infected patients in care, particularly cases caused by resistant bacteria. There is an ongoing debate in both media and research about bacterial resistance and antibiotic consumption. Resistant bacteria can be a threat to our future if we do not reduce the consumption of antibiotics and take measure against infection spreading. If it is possible to reduce the number of resistant bacteria infected patients in the future it enables a decline in antibiotic consumption. This in turn leads to a decreased quantity of bacteria that is able to develop a resistance pattern to antibiotic. Thus, it is highly motivated to study and streamline the process of infection control.   Preventive measures must be taken and the source of the infection must be identified in order to reduce the number of infected patients. The Swedish health care sector is currently working actively with infection control. The concept of infection control encloses the detection, the control and the tracing of the infection. The requestor of this master thesis, Cambio Healthcare Systems AB, does not have a complete picture of the process of the infection control. Their goal is to develop an IT system to facilitate the process of infection control. This study aims to map the information flow of the process and to identify the involved actors’ field of responsibility and obligations according to the law. Further, this thesis aims to present action proposals that can reduce the identified risks and streamline the infection control of resistant bacteria.   A case study of a Swedish university hospital was performed in the spring of 2013 in order to map the process of infection control. The investigated actors were the microbiological laboratory, the local health protection unit (Vårdhygien), the unit of infection control at a regional level (Smittskyddsenheten), the Swedish Institute of Infectious Disease Control (Smittskyddsinstitutet) and physicians and nurses at two hospital departments. The data collection consists of interviews, observations and documents.   The result of this case study shows that the process of infection control is a complex system with an extensive flow of information. The main actors are the local health protection unit, the microbiological laboratory and the medical staff. Their practical actions are essential for the process of infection control. The unit of infection control at a regional level is involved to some extent, but does not belong to the main actors. Furthermore, the study showed that the Swedish Institute of Infectious Disease Control does not have a prominent role in the process at the hospital.   The division of responsibilities is to some extent controlled by the law. According to the law, the physician in charge has a central role in the process of infection control. However, the physician’s role in reality is less prominent. Usually, the physician delegates the tasks to the other actors such as nurses or to the local health protection unit. The communication between the actors is mainly oral and this can cause risks. Most of the identified risks occurred due to human error, often in combination with use of an insufficient IT-system. Therefore, the proposed actions to streamline the process focus on minimizing the identified risks with help of future IT solutions.   The conclusion of this study is that there is a strong demand for IT solutions to streamline the process of infection control of resistant bacteria. My recommendation is that Cambio Healthcare Systems AB should focus on developing a system to digitalize the archiving of the occupancy lists, which also enables tracing the flow of patients back in time. This is a request from several health care professionals. Another important proposed action is to develop a checklist that is specific for every infection disease. Simultaneously as the physician receives the positive test results, this checklist will appear on the physician’s screen. Finally, I recommend Cambio Healthcare Systems AB to develop an alarm to infection diseases that can be integrated with their existing whiteboards that were recently introduced to the market.

A shuman beings, we are continuously struggling to comprehend the mechanism of dierent natural systems. Many times, we face a complex system where the emergent properties of the system at a global level can not be explained by a simple aggregation of the system's components at the micro-level. To better understand the macroscopic system eects, we try to model microscopic events and their interactions. In order to do so, we rely on specialized tools to connect local mechanisms with global phenomena. One such tool is network theory. Networks provide a powerful way of modeling and analyzing complex systems based on interacting elements. The interaction pattern links the elements of the system together and provides a structure that controls how information permeates throughout the system. For example, the passing of information about job opportunities in a society depends on how social ties are organized. The interaction pattern, therefore, often is essential for reconstructing and understanding the global-scale properties of the system. In this thesis, I describe tools and models of network theory that we use and develop to analyze the organization of social or transportation systems. More specifically, we explore complex networks by asking two general questions: First, which mechanistic theoretical models can better explain network formation or spreading processes on networks? And second, what are the signi cant functional units of real networks? For modeling, for example, we introduce a simple agent-based model that considers interacting agents in dynamic networks that in the quest for information generate groups. With the model, we found that the network and the agents' perception are interchangeable; the global network structure and the local information pathways are so entangled that one can be recovered from the other one. For investigating signi cant functional units of a system, we detect, model, and analyze signi cant communities of the network. Previously introduced methods of significance analysis suer from oversimpli ed sampling schemes. We have remedied their shortcomings by proposing two dierent approaches: rst by introducing link prediction and second by using more data when they are available. With link prediction, we can detect statistically signi cant communities in large sparse networks. We test this method on real networks, the sparse network of the European Court of Justice case law, for example, to detect signi cant and insigni cant areas of law. In the presence of large data, on the other hand, we can investigate how underlying assumptions of each method aect the results of the signi cance analysis. We used this approach to investigate dierent methods for detecting signi cant communities of time-evolving networks. We found that, when we highlight and summarize important structural changes in a network, the methods that maintain more dependencies in signi cance analysis can predict structural changes earlier. In summary, we have tried to model the systems with as simple rules as possible to better understand the global properties of the system. We always found that maintaing information about the network structure is essential for explaining important phenomena on the global scale. We conclude that the interaction pattern between interconnected units, the network, is crucial for understanding the global behavior of complex systems because it keeps the system integrated. And remember, everything is connected, albeit not always directly.