Ansätze zur Ordnungsreduktion von nichtlinearen Oszillatormodellen zur Anwendung im Schaltungsentwurf

Im Rahmen dieser Arbeit wird ein Konzept zur Ordnungsreduktion von höherdimensionalen nichtlinearen Oszillatormodellen vorgestellt. Hierbei werden zwei wesentliche Ziele verfolgt. Zum einen wird eine höherdimensionale Modellierung der Oszillatorschaltung verwendet. Hierdurch lassen sich die Einflüsse parasitärer Effekte sowie struktureller Erweiterungen auf das dynamische Verhalten des Systems berücksichtigen. Zum anderen wird durch eine anschließende Ordnungsreduktion über die Methode der Zentrumsmannigfaltigkeit eine zweidimensionale Systembeschreibung erzeugt, deren wesentliche Dynamik derjenigen des höherdimensionalen Systems entspricht. Durch diese, in der Ordnung reduzierte, nichtlineare und parameterabhängige Systembeschreibung wird die Anwendbarkeit nichtlinearer Analysemethoden ermöglicht bzw. vereinfacht. Mit der Anwendung der Andronov-Hopf-Bifurkationsanalyse auf das reduzierte System lässt sich eine Stabilitätsuntersuchung durchführen sowie die Amplitude und Frequenz aller Zustandsgrößen approximieren. Das vorgestellte Konzept wird anhand des Beispielsystems eines LC-Tank-VCOs durchgeführt. <br><br> In this paper, an order reduction technique for higher-dimensional nonlinear oscillator models, based on a center manifold approach, is presented. By modeling the oscillator circuit in the higher-dimensional state space, influences of parasitic elements and of structural extensions of the oscillator architecture on the dynamical system behavior can be examined. Using the proposed order reduction technique, a generalized second order model will be derived, which includes selected design parameters of the higher order model. By using an Andronov-Hopf bifurcation analysis, the reduced system can be studied with respect to stability as well as the amplitude and frequency of the individual state variables. The concept is applied to the design of LC-tank VCOs

The Academic Collaborative Center Older Adults:A description of co-creation between science, care practice and education with the aim to contribute to person-centered care for older adult

Long-term care for older adults is in transition. Organizations offering long-term care for older adults are expected to provide person-centered care (PCC) in a complex context, with older adults aging in place and participating in society for as long as possible, staff shortages and the slow adoption of technological solutions. To address these challenges, these organizations increasingly use scientific knowledge to evaluate and innovate long-term care. This paper describes how co-creation, in the sense of close, intensive, and equivalent collaboration between science, care practice, and education, is a key factor in the success of improving long-term care for older adults. Such co-creation is central in the Academic Collaborative Center (ACC) Older Adults of Tilburg University. In this ACC, Tilburg University has joined forces with ten organizations that provide care for older adults and CZ zorgkantoor to create both scientific knowledge and societal impact in order to improve the quality of person-centered care for older adults. In the Netherlands, a “zorgkantoor” arranges long-term (residential) care on behalf of the national government. A zorgkantoor makes agreements on cost and quality with care providers and helps people that are in need of care to decide what the best possible option in their situation is. The CZ zorgkantoor arranges the long-term (residential) care in the south and southwest of the Netherlands. This paper describes how we create scientific knowledge to contribute to the knowledge base of PCC for older adults by conducting social scientific research in which the perspectives of older adults are central. Subsequently, we show how we create societal impact by facilitating and stimulating the use of our scientific knowledge in daily care practice. In the closing section, our ambitions for the future are discussed

Tyrosine hydroxylase phosphorylation is under the control of serine 40

Tyrosine hydroxylase catalyzes the initial and rate-limiting step in the biosynthesis of the neurotransmitter dopamine. The phosphorylation state of Ser40 and Ser31 is believed to exert a direct effect on the enzymatic activity of tyrosine hydroxylase. Interestingly, some studies report that Ser31 phosphorylation affects Ser40 phosphorylation, while Ser40 phosphorylation has no effect on Ser31 phosphorylation, a process named hierarchical phosphorylation. Here, we provide a detailed investigation into the signal transduction mechanisms regulating Ser40 and Ser31 phosphorylation in dopaminergic mouse MN9D and Neuro2A cells. We find that cyclic nucleotide signaling drives Ser40 phosphorylation, and that Ser31 phosphorylation is strongly regulated by ERK signaling. Inhibition of ERK1/2 with UO126 or PD98059 reduced Ser31 phosphorylation, but surprisingly had no effect on Ser40 phosphorylation, contradicting a role for Ser31 in the regulation of Ser40. Moreover, to elucidate a possible hierarchical mechanism controlling tyrosine hydroxylase phosphorylation, we introduced tyrosine hydroxylase variants in Neuro2A mouse neuroblastoma cells that mimic either phosphorylated or unphosphorylated serine residues. When we introduced a Ser40Ala tyrosine hydroxylase variant, Ser31 phosphorylation was completely absent. Additionally, neither the tyrosine hydroxylase variant Ser31Asp, nor the variant Ser31Ala had any significant effect on basal Ser40 phosphorylation levels. These results suggest that tyrosine hydroxylase is not controlled by hierarchical phosphorylation in the sense that first Ser31 has to be phosphorylated and subsequently Ser40, but, conversely, that Ser40 phosphorylation is essential for Ser31 phosphorylation. Overall our study suggests that Ser40 is the crucial residue to target so as to modulate tyrosine hydroxylase activity

Safety risks among frail older people living at home in the Netherlands:A cross‐sectional study in a routine primary care sample

Frail older people face a range of problems and risks that could undermine their ability to live safely at home. A comprehensive overview of these risks, from a multidimensional perspective, is currently lacking. This study aims to examine the prevalence of risks in multiple domains of life among frail older people living at home. We used cross‐sectional data from 824 people aged 65 years and older, who received a comprehensive geriatric assessment (the interRAI Home Care [interRAI‐HC]) between 2014 and 2018, as part of routine care from 25 general practices in the region of West‐Friesland, the Netherlands. The interRAI‐HC identifies amenable risks related to people's clinical conditions, functioning, lifestyle and behaviour, and social and physical environment. Descriptive statistics were used to examine population characteristics (age, gender, marital status, living arrangements and presence of chronic conditions) and prevalence of risks. Most common risks were related to people's clinical conditions (i.e cardio‐respiratory health, urinary incontinence, pain), functioning (i.e. limitations in instrumental activities of daily living and mood) and social environment (i.e. limitations in informal care and social functioning). More than 80% of frail older people faced multiple risks, and often on multiple domains of life simultaneously. People experiencing multiple risks per person, and on multiple domains simultaneously, were more often widowed and living alone. The multidimensional character of risks among frail older people living at home implies that an integrated approach to care, comprising both health and social care, is necessary. Insight in the prevalence of these risks can give direction to care allocation decisions

'20 days protected learning' - students' experiences of an Overseas Nurses Programme - 4 years on: A retrospective survey

Background From September 2005 the Nursing and Midwifery Council (NMC) introduced new arrangements for the registration of non-EU overseas nurses which requires all applicants to undertake '20 days of protected learning' time in the UK and for some, a period of supervised practice. A survey was undertaken at Bournemouth University, which offers a '20 days protected learning only' programme, to elicit overseas nurses' demographic details, experiences in completing the programme and their 'final destinations' once registered. Methods An online survey was devised which contained a mixture of tick box and open ended questions which covered demographic details, views on the programme and final destinations This was uploaded to www.SurveyMonkey.com and sent out to nurses who had completed the Overseas Nurses Programme (ONP) with Bournemouth University (n=1050). Quantiative data were analysed using descriptive statistics and the qualitative data were coded and analysed using content analysis . Results There were 251 respondents (27.7% response rate). The typical 'profile' of a nurse who responded to the survey was female, aged 25-40 years and had been qualified for more than 5 years with a bachelors degree. The majority came from Australia on a 2 year working holiday visa and the key final destination in the UK, on registration with the NMC, was working for an agency. There were five key findings regarding experience of the programe. Of those surveyed 61.2% did not feel it necessary to undergo an ONP; 71.6% felt that they should be able to complete the programme on-line in their own country; 64.2% that the ONP should only contain information about delivery of healthcare in UK and Legal and professional (NMC) issues; 57% that European nurses should also undergo the same programme and sit an IELTS test; and 68.2% that the programme was too theory orientated; and should have links to practice (21%). Conclusions The NMC set the admissions criteria for entry to the register and Standards for an ONP. The findings of this survey raise issues regarding the percieved value and use of this approach for overseas nurses, and it may be helpful to take this into account when considering future policy

Unknown makes unloved:A case study on improving integrated health and social care in the Netherlands using a participatory approach

Many initiatives integrating health and social care have been implemented in order to provide adequate care and support to older people living at home. Further development of existing initiatives requires iterative processes of developing, implementing and evaluating improvements to current practice. This case study provides insight into the process of improving an existing integrated care initiative in the Netherlands. Using a participatory approach, researchers and local stakeholders collaborated to develop and implement activities to further improve collaboration between health and social care professionals. Improvement activities included interprofessional meetings focussing on reflection and mutual learning and workplace visits. Researchers evaluated the improvement process, using data triangulation of multiple qualitative and quantitative data sources. According to participating professionals, the improvement activities improved their communication and collaboration by establishing mutual understanding and trust. Enabling factors included the safe and informal setting in which the meetings took place and the personal relationships they developed during the project. Different organisational cultures and interests and a lack of ownership and accountability among managers hindered the improvement process, whereas issues such as staff shortages, time constraints and privacy regulations made it difficult to implement improvements on a larger scale. Still, the participatory approach encouraged the development of partnerships and shared goals on the level of both managers and professionals. This case study highlights that improving communication between professionals is an important first step in improving integrated care. In addition, it shows that a participatory approach, in which improvements are co-created and tailored to local priorities and needs, can help in the development of shared goals and trust between stakeholders with different perspectives. However, stakeholders' willingness and ability to participate in such an improvement process is challenged by many factors

The early evolution of young massive clusters: The kinematic history of NGC6611 / M16

In the first few Myr the massive stars dynamically interact, produce runaways and affect the initial binary population. Observing and interpreting the dynamics of young massive clusters is key to our understanding of the star formation process and predicting the outcome of stellar evolution. We have studied NGC6611 in the Eagle Nebula (M16), a young massive cluster hosting 19 O stars. We used Gaia EDR3 data to determine the membership, age, cluster dynamics and the kinematics of the massive stars including runaways. The membership analysis yields 137 members located at a mean distance of 1706 $\pm$ 7 pc. The colour - absolute magnitude diagram reveals a blue and a red population of pre-main-sequence stars, consistent with two distinct populations of stars. In line with earlier studies, the youngest population has a mean extinction $A_V$ = 3.6 $\pm$ 0.1 mag and an age = 1.3 $\pm$ 0.2 Myr, while the older population of stars has a mean extinction $A_V$ = 2.0 $\pm$ 0.1 mag and an age = 7.5 $\pm$ 0.4 Myr. The latter population is more spatially extended than the younger generation of stars. We argue that most of the OB stars belong to the younger population. We identify 8 runaways originating from the center of NGC6611, consistent with the dynamical ejection scenario. We show that ~ 50% of the O stars have velocities comparable to or greater than the escape velocity. These O stars can be traced back to the center of NGC6611 with kinematic ages ranging from 0 to 2 Myr. This suggests that dynamical interactions played an important role in the early evolution of NGC6611, which is surprising considering the low current stellar density. Comparing this to simulations of young massive clusters, the required initial radius of 0.1-0.5 pc is not consistent with that of NGC6611. The O stars could have initially formed in wide binaries and possibly harden through dynamical interactions.Comment: replaced with accepted version to A&A. 28 pages, 15 figure

Packing of elastic wires in spherical cavities

We investigate the morphologies and maximum packing density of thin wires packed into spherical cavities. Using simulations and experiments, we find that ordered as well as disordered structures emerge, depending on the amount of internal torsion. We find that the highest packing densities are achieved in low torsion packings for large systems, but in high torsion packings for small systems. An analysis of both situations is given in terms of energetics and comparison is made to analytical models of DNA packing in viral capsids.Comment: 4 page