The Genetic Basis of Adaptation and Speciation in Benthic and Limnetic Threespine Stickleback (Gasterosterus aculeatus)

Sympatrische benthische (am Grund des Sees lebende) und limnische (im offenen Wasser lebende) Stichlinge entwickelten sich unabhängig voneinander in fünf Seen in Britisch-Kolumbien, Kanada. Da sie sich an unterschiedliche Nischen in ihrem Lebensraum anpassten, divergierten der benthische und limnische Stichlingsökotyp in ihrer Morphologie. Diese Evolution des benthischen und limnischen Stichlingsökotyps fand parallel in allen fünf Seen statt. Die Stichlinge dieser Seen bieten somit ein exzellentes Modell zur Untersuchung, welche Rolle die natürlicher Selektion bei der Speziation und der Anpassung spielt. Obwohl die Ökologie der Speziation und der Anpassung der benthischen und limnischen Stichlinge ausführlich untersucht wurde, fehlen bislang die genetischen Grundlagen dieser Mechanismen. Ich verwendete Gesamt-Genom-Sequenzierung, um die Speziation und Anpassung von benthischen und limnischen Stichlingen in vier Seen (Paxton Lake, Priest Lake, Little Quarry Lake, Enos Lake) in Britisch-Kolumbien, Kanada, zu untersuchen. Benthische und limnische Stichlinge aller vier Seen zeigen parallele genetische Divergenz. Benthische und limnische Stichlingsökotypen waren stark divergierender natürlicher Selektion ausgesetzt, bei der abgeleitete und angestammte Allele in jeweils einer der Stichlingsökotypen selektiv favorisiert wurden. Im benthischen Ökotyp wurden erheblich mehr Genomregionen selektiert als im limnischen Ökotyp. Indem ich unterschiedliche statistische Ansätze kombinierte, identifizierte ich mit noch nie dagewesener Auflösung Genomregionen, die zur Anpassung des benthischen und limnischen Ökotyps beitragen. Dies ermöglicht mir die Identifizierung und Charakterisierung von Genen, die für die Anpassung der Ökotypen wichtige phänotypische Merkmale und biologische Prozesse kontrollieren. Durch die Verwendung von high-density genetischen Markern, die durch die Sequenzierung des gesamten Genoms generiert wurden, untersuchte ich die Abstammung der benthischen und limnischen Ökotypen und leitete daraus ein demographisches Modell für die benthischen und limnischen Stichlinge im Paxton Lake ab. Die benthischen und limnischen Stichlinge im Paxton Lake entstanden durch allopratrische Speziation gefolgt xii von sekundärem Kontakt, wobei die Populationsgröße jeweils vor 5.000 und 7.000 Jahren reduziert wurde. Ich verwendete RNA-Sequenzierung, um die Divergenz in der Genexpression zwischen dem benthischen und limnischen Ökotyp im Paxton Lake zu erforschen und deckte auf, dass genetische Veränderungen in cis-regulierenden Elementen eine wichtige Rolle in der Anpassung von benthischen und limnischen Ökotypen spielte. Bisherige Studien zeigten, dass benthische und limnische Stichlingsökotypen im Enos Lake auf Grund von erhöhter Hybridisierung in einen Hybridschwarm „kollabiert“ waren. Die genetischen Grundlagen dieses Prozess sind jedoch größtenteils unbekannt. Durch Untersuchung der Gesamt-Genom-Sequenzierdaten zeigte ich, dass der Zusammenfall des Artenpaars im Enos Lake früher begann als bisher vorhergesagt wurde. Einige Genomregionen wurden bei diesem Prozess homogenisiert, andere nicht. Letzteres ist möglicherweise auf anhaltende divergente Selektion und/oder geringe Rekombinationsraten dieser Regionen zurückzuführen

Factors Influencing Implementation of Rural Electrification Programme in Kenya: A Case of Kieni East Sub County, Nyeri County

The Government of Kenya through numerous policies and programmes have come up with the rural electrification programmes which is to play a crucial role in the provision of electricity to rural areas in a bid to spur human, social and economic development in the Country. The purpose of this study was to determine the factors influencing the implementation of rural electrification programme in Kieni East Sub County, Nyeri County. The study adopted a descriptive survey research design. The target population of the study was 4289 households and 10 Rural Electrification Authority Team in Kieni East Sub County. Simple random sampling and Purposive sampling was used to select a sample of 94 households and 5 Rural Electrification Authority Officials. The data was collected through structured questionnaires. Reliability of the questionnaires and validity was tested through piloting. Ethics in research was observed and responses were handled with utmost confidentiality, while the study ensured fair gender representation of respondents. The data was analyzed using through descriptives and presented through tables and graphs. The study found that funding, cost of electricity, alternative sources of power and demand affected implementation of Rural Electrification Programme to a great extent. Thus, these factors play a key role in determining the success of the implementation of Rural Electrification Programme in Kieni East Sub County. The study recommended that subsidizing of consumer connections cost, wiring material cost and unit cost of energy should be lowered and also provision of incentives for investments in alternative power sources such as allocation of sufficient funds and timely disbursement for implementation of grid extension in Kieni East should be encouraged by involving policy makers and the government in formulation of policies favorable for the implementation of Rural Electrification Programme in rural areas of Kenya. The study suggests that further studies should be carried out on the influence of institutional factors on the implementation of rural electrification programs in Kenya

Influence of Drought Mitigation Strategies on Food Security: A Case of Laikipia East, Laikipia County, Kenya

Achieving food security in the Kenyan ASALs during droughts is a constant challenge. Reactive approaches to drought-risk management have been ineffective and poorly coordinated leading to vulnerability of households to food insecurity despite adoption of Hyogo Framework of Action 2005-2015 (HFA). HFA recommends continuous systematic planning and management of drought risk, as it should be anticipated and planned for, in its manifest phases of normalcy, early stage, alert and emergency periods each with specific mitigation activities. The study with special reference to Laikipia East Sub-County revealed that majority of households were aware of drought mitigation strategies which influenced household food security but these were poorly coordinated, late, insufficient and lacked sufficient funding. The study also found out that household participation was low in implementation. The study recommends more capacity building on drought mitigation strategies, timely planning for drought to ensure coordinated response to drought especially in human and livestock relief projects. Finally the study recommends involvement of technical field officials and local leaders as they are better placed to identify working strategies and rightful targeting

Deep Cascade Multi-task Learning for Slot Filling in Online Shopping Assistant

Slot filling is a critical task in natural language understanding (NLU) for dialog systems. State-of-the-art approaches treat it as a sequence labeling problem and adopt such models as BiLSTM-CRF. While these models work relatively well on standard benchmark datasets, they face challenges in the context of E-commerce where the slot labels are more informative and carry richer expressions. In this work, inspired by the unique structure of E-commerce knowledge base, we propose a novel multi-task model with cascade and residual connections, which jointly learns segment tagging, named entity tagging and slot filling. Experiments show the effectiveness of the proposed cascade and residual structures. Our model has a 14.6% advantage in F1 score over the strong baseline methods on a new Chinese E-commerce shopping assistant dataset, while achieving competitive accuracies on a standard dataset. Furthermore, online test deployed on such dominant E-commerce platform shows 130% improvement on accuracy of understanding user utterances. Our model has already gone into production in the E-commerce platform.Comment: AAAI 201

Synchronized and mixed outbreaks of coupled recurrent epidemics

Epidemic spreading has been studied for a long time and most of them are focused on the growing aspect of a single epidemic outbreak. Recently, we extended the study to the case of recurrent epidemics (Sci. Rep. 5, 16010 (2015)) but limited only to a single network. We here report from the real data of coupled regions or cities that the recurrent epidemics in two coupled networks are closely related to each other and can show either synchronized outbreak pattern where outbreaks occur simultaneously in both networks or mixed outbreak pattern where outbreaks occur in one network but do not in another one. To reveal the underlying mechanism, we present a two-layered network model of coupled recurrent epidemics to reproduce the synchronized and mixed outbreak patterns. We show that the synchronized outbreak pattern is preferred to be triggered in two coupled networks with the same average degree while the mixed outbreak pattern is likely to show for the case with different average degrees. Further, we show that the coupling between the two layers tends to suppress the mixed outbreak pattern but enhance the synchronized outbreak pattern. A theoretical analysis based on microscopic Markov-chain approach is presented to explain the numerical results. This finding opens a new window for studying the recurrent epidemics in multi-layered networks

Synchronized and mixed outbreaks of coupled recurrent epidemics

Epidemic spreading has been studied for a long time and most of them are focused on the growing aspect of a single epidemic outbreak. Recently, we extended the study to the case of recurrent epidemics (Sci. Rep. 5, 16010 (2015)) but limited only to a single network. We here report from the real data of coupled regions or cities that the recurrent epidemics in two coupled networks are closely related to each other and can show either synchronized outbreak pattern where outbreaks occur simultaneously in both networks or mixed outbreak pattern where outbreaks occur in one network but do not in another one. To reveal the underlying mechanism, we present a two-layered network model of coupled recurrent epidemics to reproduce the synchronized and mixed outbreak patterns. We show that the synchronized outbreak pattern is preferred to be triggered in two coupled networks with the same average degree while the mixed outbreak pattern is likely to show for the case with different average degrees. Further, we show that the coupling between the two layers tends to suppress the mixed outbreak pattern but enhance the synchronized outbreak pattern. A theoretical analysis based on microscopic Markov-chain approach is presented to explain the numerical results. This finding opens a new window for studying the recurrent epidemics in multi-layered networks