68 research outputs found
An Analytical Model to Determine the Required Charge near Zero Crossings for Zero Voltage Switching on Single-Stage Isolated Three Phase AC/DC Series Resonant Converter
The single-stage isolated three phase AC to DC series resonant converter with optimal trajectory control technique ensures zero voltage switching for all switching events. Zero voltage switching can be achieved through the utilization of resonant current to charge or discharge parasitic and parallel capacitances of the switching node. However, near zero crossings of the resonant current, the resonant current may not be sufficient to completely charge or discharge the parasitic and parallel capacitances. In this research, an analytical model is presented and experimentally verified to determine the required charge near zero crossings for zero voltage switching in the single-stage isolated three phase AC to DC series resonant converte
Rauch-Tung-Striebel Smoother for Position Estimation of Short-Stroke Reluctance Actuators
This article presents a novel state estimator for short-stroke reluctance actuators, intended for soft-landing control applications in which the position cannot be measured in real time. One of the most important contributions regards the system modeling for the estimator. The discrete state of the hybrid system is treated as an input. Moreover, the model is simplified to facilitate the identification of parameters and the implementation of the estimator. Thus, auxiliary variables are added to the state vector in order to indirectly account for modeling errors. Another important contribution is the state estimation approach. It is based on the Rauch–Tung–Striebel fixed-interval smoother, which allows refining past data from later observations. Numerous simulations are performed to analyze and compare the proposal and several alternatives. In addition, experimental testing is presented to evaluate and validate the estimator. As the simulated and experimental analyses demonstrate, the combined effect of the novel additions results in significantly smaller estimation errors of position and velocity
Electrocardiography monitoring system and method
Systems and methods for electrocardiography monitoring use multiple capacitive sensors in order to determine reliable measurements of electrophysiological information of a patient. Relative coupling strength and/or reliability is used to select dynamically which sensors to use in order to determine, in particular, an electrocardiogram of the patient.</p
Plasma from septic shock patients induces loss of muscle protein
Contains fulltext :
97225.pdf (publisher's version ) (Open Access
The non-compact elliptic genus: mock or modular
We analyze various perspectives on the elliptic genus of non-compact
supersymmetric coset conformal field theories with central charge larger than
three. We calculate the holomorphic part of the elliptic genus via a free field
description of the model, and show that it agrees with algebraic expectations.
The holomorphic part of the elliptic genus is directly related to an
Appell-Lerch sum and behaves anomalously under modular transformation
properties. We analyze the origin of the anomaly by calculating the elliptic
genus through a path integral in a coset conformal field theory. The path
integral codes both the holomorphic part of the elliptic genus, and a
non-holomorphic remainder that finds its origin in the continuous spectrum of
the non-compact model. The remainder term can be shown to agree with a function
that mathematicians introduced to parameterize the difference between mock
theta functions and Jacobi forms. The holomorphic part of the elliptic genus
thus has a path integral completion which renders it non-holomorphic and
modular.Comment: 13 page
Nutritional psychiatry:towards improving mental health by what you eat
Does it matter what we eat for our mental health? Accumulating data suggests that this may indeed be the case and that diet and nutrition are not only critical for human physiology and body composition, but also have significant effects on mood and mental wellbeing. While the determining factors of mental health are complex, increasing evidence indicates a strong association between a poor diet and the exacerbation of mood disorders, including anxiety and depression, as well as other neuropsychiatric conditions. There are common beliefs about the health effects of certain foods that are not supported by solid evidence and the scientific evidence demonstrating the unequivocal link between nutrition and mental health is only beginning to emerge. Current epidemiological data on nutrition and mental health do not provide information about causality or underlying mechanisms. Future studies should focus on elucidating mechanism. Randomized controlled trials should be of high quality, adequately powered and geared towards the advancement of knowledge from population-based observations towards personalized nutrition. Here, we provide an overview of the emerging field of nutritional psychiatry, exploring the scientific evidence exemplifying the importance of a well-balanced diet for mental health. We conclude that an experimental medicine approach and a mechanistic understanding is required to provide solid evidence on which future policies on diet and nutrition for mental health can be based
Onderzoek naar langdurig werklozen en snelle werkhervatters:een vergelijking op harde en zachte arbeidsmarktfactoren
What is a chiral 2d CFT? And what does it have to do with extremal black holes?
The near horizon limit of the extremal BTZ black hole is a``self-dual
orbifold'' of AdS_3. This geometry has a null circle on its boundary, and thus
the dual field theory is a Discrete Light Cone Quantized (DLCQ) two dimensional
CFT. The same geometry can be compactified to two dimensions giving AdS_2 with
a constant electric field. The kinematics of the DLCQ show that in a consistent
quantum theory of gravity in these backgrounds there can be no dynamics in
AdS_2, which is consistent with older ideas about instabilities in this space.
We show how the necessary boundary conditions eliminating AdS_2 fluctuations
can be implemented, leaving one copy of a Virasoro algebra as the asymptotic
symmetry group. Our considerations clarify some aspects of the chiral CFTs
appearing in proposed dual descriptions of the near-horizon degrees of freedom
of extremal black holes.Comment: 21 pages, no fig. v2: references added, minor improvement
Concentration of antibodies against Porphyromonas gingivalis is increased before the onset of symptoms of rheumatoid arthritis
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