Lyme-borreliose : ook in Nederland

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A permanent magnet trap for buffer gas cooled atoms

Achieving precise control over an array of ultracold molecules would provide a unique tool-set for carrying out quantum simulations and quantum computations, as a result of the molecules' rich internal structure. To realise this aim, the molecules have to be cooled and trapped. This is much more difficult for molecules than for atoms due to their complex internal structure. This thesis presents preliminary work towards realising a versatile, permanent magnet trap for buffer gas cooled molecules. Atoms are used throughout to test the feasibility of the trap, as they are easier to produce and detect. Two novel methods for trapping buffer gas cooled atoms in a permanent magnet trap are investigated. The first of these involves trapping the atoms directly from a cryogenic buffer gas cooled ablation plume. Dy atoms, with a magnetic moment of 10µB, are trapped with a lifetime of 800±30 μs, thought to be limited by collisions with a high density of background buffer gas atoms remaining in the trap region. Information gained from the direct trapping experiments motivated the design of a second trapping set-up. Here, a beam of Dy atoms is first extracted from a cryogenic buffer gas source, and when this beam reaches the trapping region, a fraction of the atoms are stopped through collisions with cold helium gas present in the trapping region. This second method reduces the density of buffer gas required in the trap region. The trap lifetime achieved in this arrangement of 810±40 μs is no longer than in the direct trapping experiments, but this arrangement is much more stable and repeatable. The lifetime here is also thought to be limited by collisions with background buffer gas atoms.Open Acces

Gravity measurement, processing and evaluation: Test cases de Peel and South-Limburg

This thesis is meant to give a general overview of the process of the measurement and the adjustment of a gravity network and the computation of some output parameters of gravimetry: gravity values, gravity anomalies and mean block anomalies. In Chapter 1 a short overview of developments in gravimetry, globally and in the Netherlands, until now is given. Chapter 2 deals with the basic theory of relative gravity measurements and gives a description of the most commonly used instrument, the LaCoste and Romberg gravimeter. The surveys done in the scope of this study are described in Chapter 3. Chapter 4 gives a more detailed impression of the adjustment procedure and the results of the adjustment. In Chapter 5 a closer look is taken at the more geophysical side of gravimetry: gravity reduction, the computation of anomalies and the correlation with elevation. Chapter 6 deals with the interpolation of gravity and the covariance of gravity anomalies.Civil Engineering and Geoscience

Importrisico van meticilline-resistente staphylococcus aureus en maatregelen bij terugkeer van patiënten uit het buitenland

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Outbreak of Amoxicillin-Resistant Haemophilus influenzae Type B: Variable Number of Tandem Repeats as Novel Molecular Markers

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