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An observation of the 1S-3S and 1S-3D two-photon transitions in an atomic hydrogen beam using direct frequency-comb spectroscopy in a Doppler-free arrangement is reported. The measurements of these transition frequencies may be used for an improved determination of the Rydberg constant and the 1S Lamb shift and could shed light on the current discrepancy in the determination of the proton charge radius. Concurrently, a frequency comb well-suited for high-precision, Doppler-free spectroscopy in the deep ultraviolet (DUV) wavelength region is demonstrated.

We identify a systematic present in two-photon direct frequency comb spectroscopy (DFCS) which is a result of chirped laser pulses and is amanifestation of the first-order Doppler effect. We carefully analyze this systematic and propose methods for its mitigation within the context of our measurement of the hydrogen 1S-3S transition. We also report on our determination of the absolute frequency of this transition, which is comparable to a previous measurement using continuous-wave spectroscopy [O. Arnoult et al., Eur. Phys. J. D 60, 243 (2010)], but was obtained with a different experimental method.

Background Although this effect is well known, tailored treatment methods have not yet been broadly adopted. The aim of this study was to identify those patient characteristics that most influence the impairment of quality of life and thus to identify those patients who need and can benefit most from specific intervention treatment. Methods 1879 cancer patients were given the EORTC QLQ C-30 questionnaire at the beginning and end of their inpatient rehabilitation. Patients’ scores were compared to those of 2081 healthy adults (Schwarz and Hinz, Eur J Cancer 37:1345–1351, 2001). Furthermore, differences in quality of life corresponding to sex, age, tumor site, TNM stage, interval between diagnosis and rehabilitation, and therapy method were examined. Results Compared to the healthy population, the study group showed a decreased quality of life in all analyzed domains. This difference diminished with increasing age. Women reported a lower quality of life then men in general. Patients with prostate cancer showed the least impairment in several domains. Patients having undergone chemotherapy as well as radiotherapy were impaired the most. Surprisingly, TNM stage and interval between diagnosis and rehabilitation did not significantly influence quality of life. Global quality of life and all functional domains significantly improved after a 3-week rehabilitation program. Conclusions Despite an individualized and increasingly better tolerable therapy, the quality of life of cancer patients is still considerably impaired. However, systematic screening of psychosocial aspects of cancer, e.g. quality of life, could enable improved intervention. peerReviewed

Thanks to the high peak intensities of ultrashort pulse trains that make up an optical frequency comb, conversion to much shorter wavelengths is readily available. Therefore direct frequency comb spectroscopy may offer the possibility of extending high-resolution spectroscopy to spectral regions that are unexplored so far. In this work, we investigate the impact of a chirp, i.e., a varying frequency across the pulses, on the excitation rate obtainable with two-photon direct frequency comb spectroscopy. Using the cesium $6 {}^{2}{S}_{1/2}$-$8 {}^{2}{S}_{1/2}$ two-photon transition at $822$ nm, we show that destructive interference of various quantum paths reduces the excitation rate with the inverse of the time bandwidth product of the exciting pulses.

Increasingly computer assisted techniques are used for history matching reservoir models. Such methods will become indispensable in view of the increasing amount of information generated by intelligent wells, in which case manual interpretation becomes too time consuming. Also, with the increasing possibilities for controlling a reservoir, a better prediction of the reservoir behavior is very important. A technique that has received considerable attention lately is the Ensemble Kalman Filter (EnKF), which is a sequential updating technique based on the Bayesian notion of updating prior information with observations (measurements). The EnKF has already been proven to be useful for history matching of real fields. Some of the advantages of the EnKF are its sequential nature, the large number of parameters that can be estimated (10000+) and the fact that an uncertainty estimate is generated. The most important and time consuming step for anyone wanting to do a history match with the EnKF is creating the initial ensemble including defining all the proper initial uncertainties. This paper presents an integrated workflow for creating an initial ensemble for a channelized reservoir and updating the ensemble sequentially using the EnKF. The resulting ensemble of history matched models is then used to predict the expected production and associated uncertainty for a new production strategy. The quality of the prediction is compared to the predictions from a model which was history matched manually. The improved predictive capabilities of the models which were history matched with the EnKF allows for better optimization of the production strategy for the complex channel geometry. Moreover, the updated uncertainty estimate shows the risks involved with some of the newly proposed wells, which allows for better decision making.

Within the research framework of the "Integrated System Approach Petroleum Production" (ISAPP) knowledge center of TNO, TU Delft and Shell, the necessity of taking the interaction between dynamic reservoir and dynamic well behavior into account when optimizing a producing asset is investigated. To simulate dynamic phenomena in the well and in the reservoir, a dynamic multiphase well simulation tool (OLGA) and a dynamic multiphase reservoir simulator (MoReS) have been used. Both simulators have been coupled using an explicit scheme. The dynamic well simulator, the dynamic reservoir simulator and the coupled dynamic well-reservoir simulator have been used to simulate a realistic test case which consists of a horizontal well with three inflow sections located in a thin oil rim. A number of scenarios are investigated that play a crucial role during different stages of the well's lifetime: naturally occurring phenomena, e.g. coning, and production dynamics, e.g. shut-in. The results of dynamic well simulations, dynamic reservoir simulations and coupled well-reservoir simulations are presented and an overview is given of the cases where the results of the coupled simulations are significantly more accurate in comparison to stand-alone well or reservoir simulations. For gas coning it is shown that the coupled simulator has much faster pressure transients after gas breakthrough than the dynamic reservoir simulator. Therefore, the coupled well-reservoir simulator should be used to simulate gas breakthrough and to optimize production using gas coning control. For small time scale phenomena, order of less then one day, the well and reservoir transients overlap. Simulations show that the coupled simulator is essential for an accurate prediction of the well-reservoir interaction during these small time scale phenomena.