Population dynamics in Korogwe : demographic surveillance system (DSS) in Tanga Region, Tanzania

A demographic surveillance system (DSS) is commonly used to generate and handle longitudinal follow-up data relating to demographic and health related events in a specified area. In the Korogwe DSS site, information on vital events such as births, deaths and migration has been collected since the establishment of the site in 2005. The aim was to establish demographic and epidemiological indices so as to assist in the evaluation of health related interventions

QRA with respect to domino effects and property damage

In 1996 the European Union adopted the Seveso II Directive. The Directive stated actions to be taken in the process industry in order to prevent and limit the impact of serious chemical accidents. In the Directive it is clearly stated that domino effects shall be considered, but the level of detail required is not specified. Due to that fact and the high degree of complexity linked to domino effects, these aspects are mostly dealt with in a qualitative manner. Such approach leads to subjective assessments and is highly dependent on simplified assumptions, leading to results that may be questionable. Thus, it would be beneficial to develop a method that incorporates the risk of domino effects in a quantitative risk analysis (QRA), which has been the aim of this thesis. The method was developed based on a literature review of existing research. Focus was on integrating domino effects as a natural part of a QRA without compromising the timeframe associated to a QRA. The developed method has been applied in a case study of an oil refinery in order to evaluate how well it is applicable in practise. During the case study, the method has proven to enable the risk of property damage with regard to domino effects to be quantitatively analysed. The results from the case study, evidence the importance of taking domino effects into consideration in QRAs, as the risk may be underestimated if not

Electrical coupling of superparamagnetic tunnel junctions mediated by spin-transfer-torques

In this work, the effect of electrical coupling on stochastic switching of two in-plane superparamagnetic tunnel junctions (SMTJs) is studied, using experimental measurements as well as simulations. The coupling mechanism relies on the spin-transfer-torque (STT) effect, which enables the manipulation of the state probability of an SMTJ. Through the investigation of time-lagged cross-correlation, the strength and direction of the coupling are determined. In particular, the characteristic state probability transfer curve of each SMTJ leads to the emergence of a similarity or dissimilarity effect. The cross-correlation as a function of applied source voltage reveals that the strongest coupling occurs for high positive voltages for our SMTJs. In addition, we show state tuneability as well as coupling control by the applied voltage. The experimental findings of the cross-correlation are in agreement with our simulation results

Embedding Phylogenetic Trees in Networks of Low Treewidth

Given a rooted, binary phylogenetic network and a rooted, binary phylogenetic tree, can the tree be embedded into the network? This problem, called Tree Containment, arises when validating networks constructed by phylogenetic inference methods. We present the first algorithm for (rooted) Tree Containment using the treewidth t of the input network N as parameter, showing that the problem can be solved in 2O(t2) |N| time and space.Optimizatio

Phylogenetic incongruence through the lens of Monadic Second Order logic

International audienceWithin the field of phylogenetics there is growing interest in measures for summarising the dissimilarity, or incongruence, of two or more phylogenetic trees. Many of these measures are NP-hard to compute and this has stimulated a considerable volume of research into fixed parameter tractable algorithms. In this article we use Monadic Second Order logic to give alternative, compact proofs of fixed parameter tractability for several well-known incongruence measures. In doing so we wish to demonstrate the considerable potential of MSOL - machinery still largely unknown outside the algorithmic graph theory community - within phylogenetics. A crucial component of this work is the observation that many measures, when bounded, imply the existence of an agreement forest of bounded size, which in turn implies that an auxiliary graph structure, the display graph, has bounded treewidth. It is this bound on treewidth that makes the machinery of MSOL available for proving fixed parameter tractability

Invading the Occupied Niche: How a Parasitic Copepod of Introduced Oysters Can Expel a Congener From Native Mussels

In species introductions, non-native species are often confronted with new niches occupied by more specialized natives, and for introduced parasites this conflict can be amplified because they also face novel hosts. Despite these obstacles, invasions of introduced parasites occur frequently, but the mechanisms that facilitate parasite invasion success are only rarely explored. Here, we investigated how the parasitic copepod Mytilicola orientalis, that recently spilled over from its principal host - the Pacific oyster Crassostrea gigas, managed to invade the niche of blue mussel Mytilus edulis intestines, which is densely occupied by its specialist congener, Mytilicola intestinalis. From field observations demonstrating invasion dynamics in nature, we designed a series of experiments addressing potential mechanisms facilitating a successful occupation of the new niche. As expected the specialist M. intestinalis can only infect mussel hosts, but displayed higher infection success there than M. orientalis in both principal host species combined. In the absence of direct competitive interactions M. orientalis compensated its lower infection success (1) by recurrent spill-over from its high-fitness reservoir oyster host, and (2) by active aggregation interference enhancing its own mating success while limiting that of M. intestinalis. The introduced parasite could thus avoid direct competition by changing its own epidemiology and indirectly decreasing the reproductive success of its competitor in the new host. Such mechanisms outside of direct competition have seldom been considered, but are crucial to understand invasion success, parasite host range and community assembly in the context of species introductions

En studie om årsaksfaktorer til valg av spillselskap

Da vi skrev denne oppgaven om pengespillmarkedet, var målet vårt å indentifisere hvilke faktorer som påvirket unge mennesker mellom 18-26 år, og deres valg av spillselskap. Vi har gjennom oppgaven benyttet oss av både kvalitativ og kvantitativ metode, der de kvalitative dybdeintervjuene ble gjennomført for å fremskaffe variabler som vi ville bruke til en kvantitativ undersøkelse. Vi har også gjennom oppgaven brukt den eldre generasjon mennesker fra 50 år og oppover, som et sammenligningsgrunnlag for å besvare problemstillingen: “Hvilke faktorer påvirker unge menneskers valg av spillselskap?” Den teoretiske gjennomgangen består først av en ekstern markedsanalyse i form av en PESTELanalyse. Dette for å gi leserne en bredere forståelse av hvordan pengespillmarkedet i Norge er bygget opp. Deretter vil det i teorien være hovedfokus på den generelle beslutningsprosessen av Schiffman, Kanuk og Hansen, som kan tydeliggjøre hvilke prosesser en forbruker gjennomgår før, under og etter et kjøp. I form av hypoteser hadde vi teorier om hvilke faktorer som påvirker valg av spillselskap blant unge mennesker, og gjennom våre undersøkelser ser vi tendenser til at spesielt årsaksfaktorene “insentiver”, “produktsortiment”, “samfunnsnyttighet”, “anbefalinger” og “markedskommunikasjon” har en betydning for hvilket spillselskap som blir valgt. Videre vil vi i diskusjonsdelen drøfte funnene fra spørreundersøkelsen opp mot relevant teori, samt sette funnene våre inn i en større sammenheng via beslutningsprosessen. Tendensene vi har funnet i denne utredningen kan ikke brukes som en konklusjon for problemstillingen vår, men heller brukes som et grunnlag for videre forskning innenfor temaet

Modulation of Myelopoiesis Progenitors Is an Integral Component of Trained Immunity

Trained innate immunity fosters a sustained favorable response of myeloid cells to a secondary challenge, despite their short lifespan in circulation. We thus hypothesized that trained immunity acts via modulation of hematopoietic stem and progenitor cells (HSPCs). Administration of β-glucan (prototypical trained-immunity-inducing agonist) to mice induced expansion of progenitors of the myeloid lineage, which was associated with elevated signaling by innate immune mediators, such as IL-1β and granulocyte-macrophage colony-stimulating factor (GM-CSF), and with adaptations in glucose metabolism and cholesterol biosynthesis. The trained-immunity-related increase in myelopoiesis resulted in a beneficial response to secondary LPS challenge and protection from chemotherapy-induced myelosuppression in mice. Therefore, modulation of myeloid progenitors in the bone marrow is an integral component of trained immunity, which to date, was considered to involve functional changes of mature myeloid cells in the periphery

Protective immune trajectories in early viral containment of non-pneumonic SARS-CoV-2 infection

The antiviral immune response to SARS-CoV-2 infection can limit viral spread and prevent development of pneumonic COVID-19. However, the protective immunological response associated with successful viral containment in the upper airways remains unclear. Here, we combine a multi-omics approach with longitudinal sampling to reveal temporally resolved protective immune signatures in non-pneumonic and ambulatory SARS-CoV-2 infected patients and associate specific immune trajectories with upper airway viral containment. We see a distinct systemic rather than local immune state associated with viral containment, characterized by interferon stimulated gene (ISG) upregulation across circulating immune cell subsets in non-pneumonic SARS-CoV2 infection. We report reduced cytotoxic potential of Natural Killer (NK) and T cells, and an immune-modulatory monocyte phenotype associated with protective immunity in COVID-19. Together, we show protective immune trajectories in SARS-CoV2 infection, which have important implications for patient prognosis and the development of immunomodulatory therapies