Martin Linder

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We have evaluated the performance of two classes of probabilistic models for substitution rate variation over phylogenetic trees. In the first class, branch rates are considered to be independent and identically distributed (i.i.d.) stochastic variables. Three versions with respect to the underlying distribution (Gamma, Inverse Gaussian, and LogNormal) are(More)
The combination of liquid chromatography and mass spectrometry (LC-MS) has been established to complement gas chromatography (GC)-MS in the analysis of non-volatile and labile drugs in complex materials. The possibilities of LC-MS in the pharmaceutical industry for the analysis of drug substances and dosage forms, metabolism studies and the elucidation of(More)
The introduced electrospray (ESP) technique combined with quadrupole mass spectrometry (MS) was applied for the trace residue detection (10 ppb) of commonly administered beta-lactam antibiotics in bovine milk. Because of the widespread use of penicillin G, ampicillin, amoxicillin, cephapirin, cloxacillin, and ceftiofur in veterinary medicine, these six(More)
The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth andNeptune—all unknown in the Solar System.Observations to date have shown that our Solar(More)
The aim of this study was to investigate the applicability of the distance correction parameter (DCP) integrated to the case-based prediction system CONSTUD to reduce the effect of spatial autocorrelation of training data in machine learning process. To achieve this, calculated similarity between observations is decreased by the so-called distance(More)
The Moran model is used in population genetics as a simple way to describe the stochastic evolution of a biological population. The model assumes that the population has a fixed size N and that it evolves through random reproduction events, in which one individual dies and is replaced by a newborn. Parents of the newborn individual are chosen at random from(More)
Vibration-free miniature Joule-Thomson (JT) coolers are of interest for cooling small optical detectors for future space missions. The European Space Agency is interested in on-chip detector cooling for the temperature range 70¶K¶-¶250¶K. This is the topic of a new project at the University of Twente. In this project, the focus is on the integration of(More)
The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT will be able(More)
At the University of Twente, a 14.5 K hydrogen-based sorption cooler is under development. It can be used as a stand-alone 14.5 K cooler, or as a precooler, e.g., in combination with a 4 K heliumbased sorption cooler. The advantage of sorption coolers is the absence of moving parts and, as a result, their vibration-free operation and, potentially, a very(More)
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