An effective rotational mating scheme for inbreeding reduction in captive populations illustrated by the rare sheep breed

Within breeds and other captive populations, the risk of high inbreeding rates and loss of diversity can be high within (small) herds or subpopulations. When exchange of animals between different subpopulations is organised according to a rotational mating scheme, inbreeding rates can be restricted. Two such schemes, a breeding circle and a maximum avoidance of inbreeding scheme, are compared. In a breeding circle, flocks are organised in a circle where each flock serves as a donor flock for another flock, and the same donor–recipient combination is used in each breeding season. In the maximum inbreeding avoidance scheme, donor¿recipient combinations change each year so that the use of the same combination is postponed as long as possible. Data from the Kempisch Heideschaap were used with computer simulations to determine the long-term effects of different breeding schemes. Without exchanging rams between flocks, high inbreeding rates (>1.5% per year) occurred. Both rotational mating schemes reduced inbreeding rates to on average 0.16% per year and variation across flocks in inbreeding rates, caused by differences in flock size, almost disappeared. Inbreeding rates with maximum inbreeding avoidance were more variable than with a breeding circle. Moreover, a breeding circle is easier to implement and operate. Breeding circles are thus efficient and flexible and can also be efficient for other captive populations, such as zoo populations of endangered wild specie

Functional Analysis of Protein Interactions at Microtubule Tips

Due to a temporary embargo, Chapter 6 and Appendix B cannot yet be made available at RePub.Microtubules are a part of the cytoskeleton involved in many essential processes, such as intracellular transport of cargoes, cell migration, positioning of cellular organelles and formation of the mitotic spindle for chromosome segregation. The fast growing end of microtubules (the plus-end) can interact with specific microtubule plus-end binding proteins (also known as plus-end tracking proteins, or +TIPs). +TIPs participate in microtubule interactions with different cellular structures and control microtubule dynamics. This thesis describes the functional analysis of protein interactions at the microtubule plus-ends. The microtubule plus-end tracking protein CLIP-170 (cytoplasmic linker protein of 170 kDa) regulates its association with microtubules by changing its conformation. The folded head-to-tail conformation of CLIP-170 inhibits microtubule association and also interferes with the binding of dynactin and LIS1 to the CLIP-170 COOH terminus. The functional relationship of CLIP family members with three EB family members EB1, EB2 and EB3 is described. CLIPs bind directly to the COOH terminus of the E

Towards a systematic approach in hearing aid rehabilitation for adults

This dissertation undertakes an examination of hearing rehabilitation, weaving together the technical aspects of audiology with patient experiences. Focusing on adults using hearing aids, the research adopts a holistic approach, emphasizing the integration of Patient-Reported Outcome Measures (PROMs) with objective audiological findings. Through the analysis of retrospective data from over a thousand individuals and the employment of tools such as the “speech spatial and qualities of hearing scale” (SSQ) and the “Amsterdam Questionnaire for Auditory Impairments” (AVAB), the study identifies initial auditory disability as a main predictor of rehabilitation success. Additionally, factors such as age and prior experience with hearing aids are recognized as significant, while challenging some common assumptions about hearing aid selection and performance. Techniques like Real Ear Measurement (REM) are used to evaluate hearing aid effectiveness, stressing the importance of both objective and subjective measures. The findings advocate for a comprehensive approach that balances technical considerations with patient-centered care, offering insights that may contribute to more nuanced and individualized rehabilitation strategies. The study's results provide a measured perspective on the complex process of auditory rehabilitation, underscoring the importance of a multifaceted approach in enhancing patient outcomes

Dopant metrology in advanced FinFETs

Ultra-scaled FinFET transistors bear unique fingerprint-like device-to-device differences attributed to random single impurities. This paper describes how, through correlation of experimental data with multimillion atom tight-binding simulations using the NEMO 3-D code, it is possible to identify the impurity's chemical species and determine their concentration, local electric field and depth below the Si/SiO$_{\mathrm{2}}$ interface. The ability to model the excited states rather than just the ground state is the critical component of the analysis and allows the demonstration of a new approach to atomistic impurity metrology.Comment: 6 pages, 3 figure

Magnetic Field Probing of an SU(4) Kondo Resonance in a Single Atom Transistor

Semiconductor nano-devices have been scaled to the level that transport can be dominated by a single dopant atom. In the strong coupling case a Kondo effect is observed when one electron is bound to the atom. Here, we report on the spin as well as orbital Kondo ground state. We experimentally as well than theoretically show how we can tune a symmetry transition from a SU(4) ground state, a many body state that forms a spin as well as orbital singlet by virtual exchange with the leads, to a pure SU(2) orbital ground state, as a function of magnetic field. The small size and the s-like orbital symmetry of the ground state of the dopant, make it a model system in which the magnetic field only couples to the spin degree of freedom and allows for observation of this SU(4) to SU(2) transition.Comment: 12 pages, 10 figures, accepted for publication in Physical Review Letter

Engineered valley-orbit splittings in quantum confined nanostructures in silicon

An important challenge in silicon quantum electronics in the few electron regime is the potentially small energy gap between the ground and excited orbital states in 3D quantum confined nanostructures due to the multiple valley degeneracies of the conduction band present in silicon. Understanding the "valley-orbit" (VO) gap is essential for silicon qubits, as a large VO gap prevents leakage of the qubit states into a higher dimensional Hilbert space. The VO gap varies considerably depending on quantum confinement, and can be engineered by external electric fields. In this work we investigate VO splitting experimentally and theoretically in a range of confinement regimes. We report measurements of the VO splitting in silicon quantum dot and donor devices through excited state transport spectroscopy. These results are underpinned by large-scale atomistic tight-binding calculations involving over 1 million atoms to compute VO splittings as functions of electric fields, donor depths, and surface disorder. The results provide a comprehensive picture of the range of VO splittings that can be achieved through quantum engineering.Comment: 4 pages, 4 figure

Heterointerface effects on the charging energy of shallow D- ground state in silicon: the role of dielectric mismatch

Donor states in Si nanodevices can be strongly modified by nearby insulating barriers and metallic gates. We report here experimental results indicating a strong reduction in the charging energy of isolated As dopants in Si FinFETs relative to the bulk value. By studying the problem of two electrons bound to a shallow donor within the effective mass approach, we find that the measured small charging energy may be due to a combined effect of the insulator screening and the proximity of metallic gates.Comment: 7 pages, 6 figure