3,317 research outputs found
Determining optimal cadence for an individual road cyclist from field data
The cadence that maximises power output developed at the crank by an individual cyclist is conventionally determined using a laboratory test. The purpose of this study was two-fold: (i) to show that such a cadence, which we call the optimal cadence, can be determined using power output, heart-rate, and cadence measured in the field and (ii) to describe methodology to do so. For an individual cyclist's sessions, power output is related to cadence and the elicited heart-rate using a non-linear regression model. Optimal cadences are found for two riders (83 and 70 revolutions per minute, respectively); these cadences are similar to the riders’ preferred cadences (82–92?rpm and 65–75?rpm). Power output reduces by approximately 6% for cadences 20?rpm above or below optimum. Our methodology can be used by a rider to determine an optimal cadence without laboratory testing intervention: the rider will need to collect power output, heart-rate, and cadence measurements from training and racing sessions over an extended period (>6 months); ride at a range of cadences within those sessions; and calculate his/her optimal cadence using the methodology described or a software tool that implements it
Recombinant human epoetin beta in the treatment of chemotherapy-related anemia
Anemia is a common complication of systemic anti-cancer treatment. In this context epoetin beta, like other erythropoiesis-stimulating agents (ESAs), has demonstrable efficacy in raising Hb concentration and reducing the requirement for red cell transfusion. Consequently ESA therapy has gained increasing prominence in the management of chemotherapy-related anemia. However, recent trial data have suggested a higher rate of thromboembolic events, enhanced tumor progression and reduced survival in some patients with cancer who receive ESA therapy. In response, regulatory authorities have mandated increasingly restrictive label changes. In light of these new developments we consider the current role of epoetin beta in the management of chemotherapy-related anemia
A mathematical model to determine optimum cadence for an individual cyclist using power output, heart rate and cadence data collected in the field
We aim to develop a methodology to determine individual optimum cadences for competitive cyclists using field data. Cadence is the number of pedal crank revolutions per minute or pedalling rate. Currently athletes tend to select a cadence intuitively (choosing a gear that permits a cadence that feels comfortable), with some advice from coaches. Literature defines optimum cadence based on gross efficiency. However only power output, heart rate and cadence measurements from the field are available to us. Hence we determine an optimum cadence as the cadence that minimises heart rate for a given power output. In so doing we consider heart rate a reasonable proxy for gross efficiency. We fit statistical models of power output, heart rate amd cadence, with heart rate lagged behind changes in power output, at various lags (though we believe 30 seconds is appropriate). We consider the effect of fatigue on optimum cadence through calculation of training impulses or TRIMPs, but do not consider the effects of fitness, gradient, or whether athletes are standing or sitting. Optimum cadences are found for two athletes (83 and 70 revolutions per minute respectively); these cadences are similar to athletes’ preferred cadences (82-92 and 65-75 rpm respectively). Optimum cadences do not vary by power output or heart rate in our study, and are relatively insensitive to TRIMP. Power output reduces by approximately 2% for cadences 10 rpm above or below optimum. The methodology we propose can be implemented by a wide range of competitive cyclists to calculate optimum cadence; cyclists need to collect power output, heart rate and cadence measurements from training sessions over an extended period (>6 months), and ride at a range of cadences within those sessions. Cyclists and their coaches can re-calculate optimum cadence, say every 6 months, to take account of possible changes in fitness
Neural network interpolation of the magnetic field for the LISA Pathfinder Diagnostics Subsystem
LISA Pathfinder is a science and technology demonstrator of the European
Space Agency within the framework of its LISA mission, which aims to be the
first space-borne gravitational wave observatory. The payload of LISA
Pathfinder is the so-called LISA Technology Package, which is designed to
measure relative accelerations between two test masses in nominal free fall.
Its disturbances are monitored and dealt by the diagnostics subsystem. This
subsystem consists of several modules, and one of these is the magnetic
diagnostics system, which includes a set of four tri-axial fluxgate
magnetometers, intended to measure with high precision the magnetic field at
the positions of the test masses. However, since the magnetometers are located
far from the positions of the test masses, the magnetic field at their
positions must be interpolated. It has been recently shown that because there
are not enough magnetic channels, classical interpolation methods fail to
derive reliable measurements at the positions of the test masses, while neural
network interpolation can provide the required measurements at the desired
accuracy. In this paper we expand these studies and we assess the reliability
and robustness of the neural network interpolation scheme for variations of the
locations and possible offsets of the magnetometers, as well as for changes in
environmental conditions. We find that neural networks are robust enough to
derive accurate measurements of the magnetic field at the positions of the test
masses in most circumstances
Spatially valid proprioceptive cues improve the detection of a visual stimulus
Vision and proprioception are the main sensory modalities that convey hand location and direction of movement. Fusion of these sensory signals into a single robust percept is now well documented. However, it is not known whether these modalities also interact in the spatial allocation of attention, which has been demonstrated for other modality pairings. The aim of this study was to test whether proprioceptive signals can spatially cue a visual target to improve its detection. Participants were instructed to use a planar manipulandum in a forward reaching action and determine during this movement whether a near-threshold visual target appeared at either of two lateral positions. The target presentation was followed by a masking stimulus, which made its possible location unambiguous, but not its presence. Proprioceptive cues were given by applying a brief lateral force to the participant’s arm, either in the same direction (validly cued) or in the opposite direction (invalidly cued) to the on-screen location of the mask. The d′ detection rate of the target increased when the direction of proprioceptive stimulus was compatible with the location of the visual target compared to when it was incompatible. These results suggest that proprioception influences the allocation of attention in visual spac
Quantum Non-demolition Detection of Single Microwave Photons in a Circuit
Thorough control of quantum measurement is key to the development of quantum
information technologies. Many measurements are destructive, removing more
information from the system than they obtain. Quantum non-demolition (QND)
measurements allow repeated measurements that give the same eigenvalue. They
could be used for several quantum information processing tasks such as error
correction, preparation by measurement, and one-way quantum computing.
Achieving QND measurements of photons is especially challenging because the
detector must be completely transparent to the photons while still acquiring
information about them. Recent progress in manipulating microwave photons in
superconducting circuits has increased demand for a QND detector which operates
in the gigahertz frequency range. Here we demonstrate a QND detection scheme
which measures the number of photons inside a high quality-factor microwave
cavity on a chip. This scheme maps a photon number onto a qubit state in a
single-shot via qubit-photon logic gates. We verify the operation of the device
by analyzing the average correlations of repeated measurements, and show that
it is 90% QND. It differs from previously reported detectors because its
sensitivity is strongly selective to chosen photon number states. This scheme
could be used to monitor the state of a photon-based memory in a quantum
computer.Comment: 5 pages, 4 figures, includes supplementary materia
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