Integral multidisciplinary rehabilitation treatment planning

This paper presents a methodology to plan treatments for rehabilitation outpatients. These patients require a series of treatments by therapists from various disciplines. In current practice, when treatments are planned, a lack of coordination between the different disciplines, along with a failure to plan the entire treatment plan at once, often occurs. This situation jeopardizes both the quality of care and the logistical performance. The multidisciplinary nature of the rehabilitation process complicates planning and control. An integral treatment planning methodology, based on an integer linear programming (ILP) formulation, ensures continuity of the rehabilitation process while simultaneously controlling seven performance indicators including access times, combination appointments, and therapist utilization. We apply our approach to the rehabilitation outpatient clinic of the Academic Medical Center (AMC) in Amsterdam, the Netherlands. Based on the results of this case, we are convinced that our approach can be valuable for decision-making support in resource capacity planning and control at many rehabilitation outpatient clinics. The developed model will be part of the new hospital information system of the AMC

Flexible nurse staffing based on hourly bed census predictions

Workload on nursing wards depends highly on patient arrivals and patient lengths of stay, which are both inherently variable. Predicting this workload and staffing nurses accordingly is essential for guaranteeing quality of care in a cost effective manner. This paper introduces a stochastic method that uses hourly census predictions to derive efficient nurse staffing policies. The generic analytic approach minimizes staffing levels while satisfying so-called nurse-to-patient ratios. In particular, we explore the potential of flexible staffing policies which allow hospitals to dynamically respond to their fluctuating patient population by employing float nurses. The method is applied to a case study of the surgical inpatient clinic of the Academic Medical Center (AMC) Amsterdam. This case study demonstrates the method's potential to study the complex interaction between staffing requirements and several interrelated planning issues such as case mix, care unit partitioning and size, and surgical block planning. Inspired by the numerical results, the AMC decided that this flexible nurse staffing methodology will be incorporated in the redesign of the inpatient care operations during the upcoming years

Integral resource capacity planning for inpatient care services based on hourly bed census predictions

The design and operations of inpatient care facilities are typically largely historically shaped. A better match with the changing environment is often possible, and even inevitable due to the pressure on hospital budgets. Effectively organizing inpatient care requires simultaneous consideration of several interrelated planning issues. Also, coordination with upstream departments like the operating theater and the emergency department is much-needed. We present a generic analytical approach to predict bed census on nursing wards by hour, as a function of the Master Surgical Schedule (MSS) and arrival patterns of emergency patients. Along these predictions, insight is gained on the impact of strategic (i.e., case mix, care unit size, care unit partitioning), tactical (i.e., allocation of operating room time, misplacement rules), and operational decisions (i.e., time of admission/discharge). The method is used in the Academic Medical Center Amsterdam as a decision support tool in a complete redesign of the inpatient care operations

Initial spare parts assortment decision making for rolling stock maintenance: a structured approach

Design for maintenance and maintenance operations become increasingly important in recent years. In the capital-intensive industry, maintenance expenditures can add up to several times the initial investment. In order to be competitive in their business, owners and users of these capital goods have to take into account the total life cycle cost at investment (the lifespan of a train is about 30 years), the renewal decisions for their installations and the logistic management of the spare parts. Erroneous or unstructured initial spare parts assortment decision-making part of the logistic management can lead to undesired downtime and increases the risk of obsolete or unavailable components. Decision making is further complicated by non- existent data in the early design phase and several information management problems. Based on a case study at NedTrain (the largest maintainer of rolling stock in the Netherlands) and literature review a Decision Support Model to structure and to improve the initial spare part assortment for the rolling stock maintenance is proposed

Lifetime impact identification for continuous improvement of wind farm performance

To become profitable, the cost of offshore windfarms must be reduced. Optimization of the Operations & Maintenance process offers a great potential for cost reductions, especially for existing windfarm. As Continuous Improvement may deliver these cost reductions, this paper aims at fostering CI in the offshore wind industry. In order to identify where to focus CI efforts, we turn to the theory of Asset Life Cycle Management which shows that a shared multidisciplinary understanding of the complete lifetime of a windfarm is critical. Based on a case study at a leading offshore wind farm company, it is concluded that the Lifetime Impact Identification Analysis delivers such a shared understanding by bringing employees from different backgrounds together. Based on this understanding, CI priorities can be set and management may become proactive instead of having to do ‘fire-fighting’

Electron transport through the nitrogenase enzyme complex of Azotobacter vinelandii

In Chapter VII (Discussion) the current thoughts as they were accepted in 1980 about the electron transport within the nitrogenase complex are summarized. The starting points and ideas about the subject of this thesis are also given. In this way, Chapter VII can be considered both as a summary and as a discussion for the scientific interested reader. For those, who are less familiar with this kind of research, the following summary gives the results of this study which emerge in the different chapters.In the biological N-cycle, the fixation of atmospheric dinitrogen is a key reaction. The enzyme nitrogenase catalyzes the reduction of dinitrogen to ammonia. The structure and function of nitrogenase isolated from different organisms is very similar, so most conclusions drawn from experiments with one particular nitrogenase can be extended to other nitrogenases as well. In this thesis experiments are described with nitrogenase from Azotobactervinelandii .The enzyme is invitro easily separated into two components, both essential for activity. The smallest component is called the Fe- protein and its function seems to be restricted to reduce specifically the bigger component, the MoFe-protein. This electron transfer only occurs when MgATP is present and MgATP is hydroylzed to MgADP and Pi during electron transfer. The actual reaction, the reduction of dinitrogen to ammonia, takes place on the MoFe-protein.Both proteins have iron/sulphur clusters, structures consisting of alternating iron and sulphide atoms, where the necessary electrons can be stored. The Fe-protein is thought to have only one iron/sulphur cluster of the [4Fe-4S] type, which is also found in ferredoxins. This kind of cluster can take up or donate only one electron.Although the experiments, which give rise to this hypothesis, seem very convincing, there are also observations described in literature which are not compatible with the view of one [4Fe-4S] cluster per molecule Fe-protein and a one electron donor/acceptor behaviour in redox reactions.This discrepancy is also present in this thesis. In chapter H for instance, redox reactions are described where the redox state of the Fe-protein is followed by means of EPR spectroscopy and by the activity of the intact enzyme complex. From the results obtained it can be concluded that possibly two electrons are involved in the redox reaction of Fe-protein with the MoFe protein. The experiments described in chapter III confirm this view. In these experiments the number of electrons Is determined which can be accepted by oxidized Fe-protein. In stopped-flow experiments dyeoxidized Fe-protein could accept two electrons from reduced methyl viologen. Since it is possible that the Fe-protein is over-oxidized by dyes, also the physiologically oxidized Fe-protein has been used. Also in this case the results obtained are more compatible with the view that Fe-protein behaves as a two electron donor/acceptor.Because of the fact that a [4Fe-4S] cluster can only react as a one electron redox centre, we examined our Fe-protein preparations by means of Proton Induced X-ray Emission Spectroscopy (PIXES) on the presence of other metal ions which could function as an electron acceptor. No other metals than Fe could be detected. But we found a much higher iron content than could be expected by assuming one [4Fe-4S] cluster. This gave rise to a thorough analysis of the iron/sulphide content of Fe-protein (chapter IV). The maximum number of iron and sulphide atoms found per molecule was eight. This combined with the results of Mössbauer experiments which indicate that all iron atoms are in an equal configuration, gave rise to the view that probably two [4Fe-4S] clusters are present in active Fe-protein.In chapter V, it was shown that the growth conditions determine the iron/sulphide content of isolated Fe-protein. During this investigation the maximum number of iron and sulphide atoms per molecule Fe-protein was six and not eight. The discrepancy between the values reported in chapters IV and V are discussed in chapter V.Mössbauer spectroscopy experiments were not restricted to the Fe-protein, but also the MoFe-protein has been subject of examination. The importance of our results are not only restricted to the fact that the specific activity of the protein sample used is much higher than that of others, but also the processing of the primary data has been altered. This resulted in a different ratio of Fe to Mo of the FeMo-cofactor of MoFe-protein. Due to this fact the composition of the other iron/sulphur clusters present in MoFe-protein is now questionable.It is clear that the work described in this thesis has not solved the problem of the composition and structure of the metal- sulphide clusters present in the nitrogenase proteins. Beside the described experiments which may lead to the discovery of the true nature of these clusters, an Important aspect is that the general accepted dogma that the structure of the metal-sulphide clusters of nitrogenase has been solved is questioned and reopened the reserach towards a better understanding of the structures and function of these clusters

Tunneling in Fractional Quantum Mechanics

We study the tunneling through delta and double delta potentials in fractional quantum mechanics. After solving the fractional Schr\"odinger equation for these potentials, we calculate the corresponding reflection and transmission coefficients. These coefficients have a very interesting behaviour. In particular, we can have zero energy tunneling when the order of the Riesz fractional derivative is different from 2. For both potentials, the zero energy limit of the transmission coefficient is given by $\mathcal{T}_0 = \cos^2{\pi/\alpha}$, where $\alpha$ is the order of the derivative ($1 < \alpha \leq 2$).Comment: 21 pages, 3 figures. Revised version; accepted for publication in Journal of Physics A: Mathematical and Theoretica

Kwaliteit van champignons : geremde hoedopening en meer smaak

Het doel is te komen tot een praktisch toepasbare methode en protocollen om op het bed componenten toe te dienen die effect hebben op remming van de hoedopening en verhoging van smaak tijdens de naoogst-fase. Het idee is bij voorkeur vlak voor de oogst jasmonaten toe te dienen en na te gaan of hoedopeningsremming wordt bereikt in de naoogst fase. In de wetenschappelijke literatuur wordt melding gemaakt van het feit dat toedienen van een voorloper in de biosynthese van de belangrijkste smaakcomponent, 1-octen-3-ol, meer van deze smaakcomponent wordt aangemaakt en de smaak intenser wordt. Dit is aangetoond bij extracten van champignon voor toepassing in de levensmiddelenindustrie als toevoeging van champignonaroma (patent van Nestlé, Zwitserland) en in vloeibare mycelium cultures