The effects of a lion (Panthera Leo) re-introduction on a resident cheetah (Acinonyx Jubatus) population In Mountain Zebra National Park, Eastern Cape, South Africa

The global decline of large (> 10 kg) carnivores has resulted in a variety of conservation measures being put into practice to prevent extinctions. The establishment of predator-proof fences around protected areas has been a successful tool for reducing human-predator conflict. Furthermore, the re-introduction of large carnivores into small (< 1 000 km²), enclosed reserves has aided in the conservation of many species. Cheetahs (Acinonyx jubatus) and lions (Panthera leo) have benefitted from such re-introductions. The re-introduction of cheetahs before lions into the Mountain Zebra National Park (MZNP) in the Eastern Cape Province of South Africa provided a unique opportunity to study the effects of lions on an already established cheetah population. Spatial data were downloaded remotely from GPS collared individuals (n=4) and cheetah kill data were collected using the GPS cluster method before (2012-2013) and after (2013-2014) the lion (n=3) re-introduction. The same methods were used for lion kill data collection once they had been re-introduced. In general, cheetah home range size did not change after the lion re-introduction. Cheetahs selected areas with a combination of open and closed vegetation covers, while lions selected either open or closed areas of vegetation covers. In addition, as vegetation cover became thicker, the presence of cheetahs decreased. The cheetahs preyed upon seven species before and 11 species after the lion re-introduction. Medium sized prey comprised the bulk of the cheetah diet with kudu (Tragelaphus strepsiceros) and springbok (Antidorcas marsupialis) being the preferred species both before and after the lion re-introduction. The lion diets consisted of medium to large sized prey, with the male lions selecting eland (Tragelaphus oryx) and buffalo (Syncerus caffer) and the lioness selecting red hartebeest (Alcelaphus buselaphus). The cheetahs had no significant dietary overlap with the lions and there was only one record of kleptoparasitism. The results of my study indicate that cheetahs are able to co-exist with lions when lions are at low densities in an enclosed reserve. The cheetahs did not experience landscape-level displacement because they made fine-scale adjustments to avoid lions within their environment. This adaptability may have important management implications for future re-introductions of cheetahs into enclosed game reserves

Quantitative approaches in support of the early development of T-cell redirecting therapies

T-cell redirecting therapies such as CD3-bispecific antibodies and CAR-T cells are promising assets in our fight against cancer. By redirecting T-cells towards tumour cells, these therapies induce efficient eradication of tumours. Many questions remain regarding their efficacy and safety in patients. The success of a drug candidate starts with nonclinical investigations before going into patients. This work focused on developing tools to improve the translatability of nonclinical research of T-cell redirecting therapies. In this work, a mechanistic in silico model was developed that integrates an in vitro dataset of the pharmacology of cibisatamab, a CD3-bispecific antibody. The model may serve as a tool in early development to explore and quantify the impact of target expression densities on the pharmacology of CD3-bispecifics. Also, this work proposed the collection of data over multiple time points and designed a new experimental setup and analysis that allows assessing the pharmacology in an unbiased and time-independent manner. As such, the kinetics of experimental readouts can be considered to make informed decisions about the development of the compound and assist in dose selection. Lastly, the work presents a fresh look on cytokine release syndrome and identifies drug-target disease related factors and individual risk factors as the root cause of CRS. It postulates a combination of mechanistic modelling with real world data to enable individualized risk assessment.Gerichtete T-Zell-Therapien sind ein vielversprechendes Mittel im Kampf gegen Krebs. Bei dieser Therapie werden T-Zellen auf Tumorzellen gerichtet, was zu einer hocheffizienten Abtötung des Tumors führt. Es bleiben viele Fragen bezüglich ihrer Wirksamkeit und Sicherheit offen. Der Erfolg eines Arzneimittels beginnt mit nichtklinischen Untersuchungen. Diese Dissertation konzentrierte sich auf die Entwicklung Instrumente zur Verbesserung der nichtklinischen Forschung von gerichtete T-Zell-Therapien. In dieser Dissertation wurde ein mechanistisches In-silico-Modell entwickelt, das einen in-vitro-Datensatz zur Pharmakologie von cibisatamab integriert. Das Modell kann als Werkzeug in der Entwicklung dienen, um die Auswirkungen der Targetdichten auf die Pharmakologie von CD3-bispezifischen Antikörpern zu quantifizieren. In dieser Dissertation wurde auch ein neuer Versuchsaufbau und Analyse entwickelt, die eine unverzerrte und zeitunabhängige Bewertung der pharmakologischen Aktivität ermöglicht. Auf diese Weise kann die Kinetik der Messwerte berücksichtigt werden. Dies ist von Bedeutung, um fundierte Entscheidungen über die Entwicklung der Wirkstoffe und die Dosisauswahl zu treffen. Schließlich wirft die Arbeit einen Blick auf das Cytokine Release Syndrome und identifiziert Risikofaktoren als Ursache für CRS und empfiehlt eine Kombination von Modellierung und real-world Daten zur Ermöglichung einer individuellen CRS Risikobewertung bei der Behandlung mit gerichteten T-Zell-Therapien

Optimization of constant power control of wind turbines to provide power reserves

In several countries, the wind power penetration increased tremendously in the last years. As the current wind turbines do not participate in frequency control nor reserve provision, this may compromise the proper functioning of the primary control and the provision of power reserves. If no actions are taken, increasing levels of wind penetration may result in serious problems concerning the stable operation of the power system. This paper focuses on the provision of power reserves by wind turbines. For this service, the constant power control strategy is chosen as control strategy, as it gives a constant power output and has the ability to provide power reserves. In this way, the wind turbine behaves more like a conventional power plant. The choice of the power reference value is crucial as it determines whether or not a stable operation of the wind turbine is possible and power reserves can be provided. In this paper, an algorithm is proposed to obtain the range of possible reference values. By means of simulations, the optimal reference value to provide power reserves with a single wind turbine is obtained. Also, reserve provision in a wind farm is investigated. It is shown that the provision of power reserves with wind turbines using the constant power strategy is possible, especially in wind farms

Contribution of a smart transformer in the local primary control of a microgrid

In order to enable an easy participation of microgrids in the electricity markets, the smart transformer (ST) concept has been developed. The ST controls the power exchange between a microgrid and the utility network by only controlling its microgrid side voltage, instead of the conventional arrangement where new set points are communicated to all microgrid elements. When the voltage-based droop (VBD) control is implemented in the DG units, loads and storage elements, all microgrid units automatically respond to this change of microgrid voltage by altering their power output or consumption. However, this reference value of power exchange is dependent on (day-ahead) predictions of both consumption and (renewable) power generation. Hence, when these predictions prove to be inaccurate, the ST will still control the power exchange, but with consequently large variations of the microgrid voltage from its nominal value. It is suggested to take the real-time microgrid voltage into account when determining the reference power of the ST. This is presented in this paper by extending the ST's control strategy with a VBD control, such that the ST can contribute in the primary control. Simulations are included to analyze this primary control of the ST combined with VBD control of the other microgrid elements

Emerging catalytic processes for the production of adipic acid

Research efforts to find more sustainable pathways for the synthesis of adipic acid have led to the introduction of new catalytic processes for producing this commodity chemical from alternative resources. With a focus on the performance of oxygen and hydrogen peroxide as preferred oxidants, this minireview summarizes recent advances made in the selective oxidation of cyclohexene, cyclohexane, cyclohexanone and n-hexane to adipic acid. Special attention is paid to the exploration of catalytic pathways involving lignocellulosic biomass-derived chemicals such as 5-hydroxymethylfurfural, D-glucose, γ-valerolactone and compounds representative of lignin and lignin-derived bio-oils.onds voor Wetenschappelijk Onderzoek--Vlaanderen (Postdoctoral Fellowship)Belgian American Educational Foundation, Inc.Fulbright Institute of International Relation