Fidelity for imperfect postselection

We describe a simple measure of fidelity for mixed state postselecting devices. The measure is most appropriate for postselection where the task performed by the output is only effected by a specific state.Comment: 8 Pages, 8 Figure

Magnetic activity on AB Doradus: Temporal evolution of starspots and differential rotation from 1988 to 1994

Surface brightness maps for the young K0 dwarf AB Doradus are reconstructed from archival data sets for epochs spanning 1988 to 1994. By using the signal-to-noise enhancement technique of Least-Squares Deconvolution, our results show a greatly increased resolution of spot features than obtained in previously published surface brightness reconstructions. These images show that for the exception of epoch 1988.96, the starspot distributions are dominated by a long-lived polar cap, and short-lived low to high latitude features. The fragmented polar cap at epoch 1988.96 could indicate a change in the nature of the dynamo in the star. For the first time we measure differential rotation for epochs with sufficient phase coverage (1992.05, 1993.89, 1994.87). These measurements show variations on a timescale of at least one year, with the strongest surface differential rotation ever measured for AB Dor occurring in 1994.86. In conjunction with previous investigations, our results represent the first long-term analysis of the temporal evolution of differential rotation on active stars.Comment: accepted by MNRAS 18 pages 18 figure

Method for detecting coliform organisms

A method and apparatus are disclosed for determining the concentration of coliform bacteria in a sample. The sample containing the coliform bacteria is cultured in a liquid growth medium. The cultured bacteria produce hydrogen and the hydrogen is vented to a second cell containing a buffer solution in which the hydrogen dissolves. By measuring the potential change in the buffer solution caused by the hydrogen, as a function of time, the initial concentration of bacteria in the sample is determined. Alternatively, the potential change in the buffer solution can be compared with the potential change in the liquid growth medium to verify that the potential change in the liquid growth medium is produced primarily by the hydrogen gas produced by the coliform bacteria

Contemplative Practices: A Strategy to Improve Health and Reduce Disparities.

Health has many dimensions, and intolerance and lack of compassion may contribute to the poor health and disparities in our nation. Tolerance can convey an inherent paradox or dissonance that can be associated with stress. However, tolerance has a dimension of acceptance, an acknowledgement and acceptance of what "is" at the present moment, that can relieve tension associated with differing beliefs and practices. Compassionate consideration of others can be combined with acceptance to create harmony within and across individuals. In this article, we explore how contemplative practices can cultivate tolerance and compassion and contribute to improvements in individual and population health

Development of optical diaphragm deflection sensors

The objective of this project was to develop high-temperature pressure sensors using non-metallic components and optical sensing methods. The sensors are to operate over a temperature range from room temperature approx. 20C to 540C, to respond to internal pressure up to 690 kPa, to respond to external pressure up to 690 kPa, and to withstand external overpressure of 2070 kPa. Project tasks include evaluating sensing techniques and sensor systems. These efforts include materials and sensing method selection, sensor design, sensor fabrication, and sensor testing. Sensors are tested as a function of temperature, pressure, overpressure, and vibration. The project results show that high-temperature pressure sensors based on glass components and optical sensing methods are feasible. The microbend optical diaphragm deflection sensor exhibits the required sensitivity and stability for use as a pressure sensor with temperature compensation. for the microbend sensor, the 95% confidence level deviation of input pressure from the pressure calculated from the overall temperature-compensated calibration equation is 3.7% of full scale. The limitations of the sensors evaluated are primarily due to the restricted temperature range of suitable commercially available optical fibers and the problems associated with glass-to-metal pressure sealing over the entire testing temperature range

Surprisingly different star-spot distributions on the near equal-mass equal-rotation-rate stars in the M dwarf binary GJ 65 AB

We aim to understand how stellar parameters such as mass and rotation impact the distribution of star-spots on the stellar surface. To this purpose, we have used Doppler imaging to reconstruct the surface brightness distributions of three fully convective M dwarfs with similar rotation rates. We secured high cadence spectral time series observations of the 5.5 au separation binary GJ 65, comprising GJ 65A (M5.5V, Prot = 0.24 d) and GJ 65B (M6V, Prot = 0.23 d). We also present new observations of GJ 791.2A (M4.5V, Prot = 0.31 d). Observations of each star were made on two nights with UVES, covering a wavelength range from 0.64 - 1.03μm. The time series spectra reveal multiple line distortions that we interpret as cool star-spots and which are persistent on both nights suggesting stability on the time-scale of 3 d. Spots are recovered with resolutions down to 8.3° at the equator. The global spot distributions for GJ 791.2A are similar to observations made a year earlier. Similar high latitude and circumpolar spot structure is seen on GJ 791.2A and GJ 65A. However, they are surprisingly absent on GJ 65B, which instead reveals more extensive, larger, spots concentrated at intermediate latitudes. All three stars show small amplitude latitude-dependent rotation that is consistent with solid body rotation. We compare our measurements of differential rotation with previous Doppler imaging studies and discuss the results in the wider context of other observational estimates and recent theoretical predictions

Is it possible to detect planets around young active G and K dwarfs?

Theoretical predictions suggest that the distribution of planets in very young stars could be very different to that typically observed in Gyr old systems that are the current focus of radial velocity surveys. However, the detection of planets around young stars is hampered by the increased stellar activity associated with young stars, the signatures of which can bias the detection of planets. In this paper, we place realistic limitations on the possibilities for detecting planets around young active G and K dwarfs. The models of stellar activity based on tomographic imaging of the G dwarf HD 141943 and the K1 dwarf AB Dor also include contributions from plage and many small random starspots. Our results show that the increased stellar activity levels present on young solar-type stars strongly impacts the detection of Earth-mass and Jupiter-mass planets and that the degree of activity jitter is directly correlated with stellar v sin i. We also show that for G and K dwarfs, the distribution of activity in individual stars is more important than the differences in induced radial velocities as a function of spectral type. We conclude that Jupiter-mass planets can be detected close-in around fast-rotating young active stars, Neptune-mass planets around moderate rotators and that Super-Earths are only detectable around very slowly rotating stars. The effects of an increase in stellar activity jitter by observing younger stars can be compensated for by extending the observational base-line to at least 100 epochs.Peer reviewe

The relation between stellar magnetic field geometry and chromospheric activity cycles - I. The highly variable field of ɛ Eridani at activity minimum

The young and magnetically active K dwarf Epsilon Eridani exhibits a chromospheric activity cycle of about 3 years. Previous reconstructions of its large-scale magnetic field show strong variations at yearly epochs. To understand how Epsilon Eridani's large-scale magnetic field geometry evolves over its activity cycle we focus on high cadence observations spanning 5 months at its activity minimum. Over this timespan we reconstruct 3 maps of Epsilon Eridani's large-scale magnetic field using the tomographic technique of Zeeman Doppler Imaging. The results show that at the minimum of its cycle, Epsilon Eridani's large-scale field is more complex than the simple dipolar structure of the Sun and 61 Cyg A at minimum. Additionally we observe a surprisingly rapid regeneration of a strong axisymmetric toroidal field as Epsilon Eridani emerges from its S-index activity minimum. Our results show that all stars do not exhibit the same field geometry as the Sun and this will be an important constraint for the dynamo models of active solar-type stars

The influence of muscle pennation angle and cross-sectional area on contact forces in the ankle joint

Data about a muscle’s fibre pennation angle and physiological cross-sectional area are used in musculoskeletal modelling to estimate muscle forces, which are used to calculate joint contact forces. For the leg, muscle architecture data are derived from studies that measured pennation angle at the muscle surface, but not deep within it. Musculoskeletal models developed to estimate joint contact loads have usually been based on the mean values of pennation angle and physiological cross-sectional area. Therefore, the first aim of this study was to investigate differences between superficial and deep pennation angles within each muscle acting over the ankle and predict how differences may influence muscle forces calculated in musculoskeletal modelling. The second aim was to investigate how inter-subject variability in physiological cross-sectional area and pennation angle affects calculated ankle contact forces. Eight cadaveric legs were dissected to excise the muscles acting over the ankle. The mean surface and deep pennation angles, fibre length and physiological cross-sectional area were measured. Cluster analysis was applied to group the muscles according to their architectural characteristics. A previously validated OpenSim model was used to estimate ankle muscle forces and contact loads using architecture data from all eight limbs. The mean surface pennation angle for soleus was significantly greater (54%) than the mean deep pennation angle. Cluster analysis revealed three groups of muscles with similar architecture and function: deep plantarflexors and peroneals, superficial plantarflexors and dorsiflexors. Peak ankle contact force was predicted to occur before toe-off, with magnitude greater than five times bodyweight. Inter-specimen variability in contact force was smallest at peak force. These findings will help improve the development of experimental and computational musculoskeletal models by providing data to estimate force based on both surface and deep pennation angles. Inter-subject variability in muscle architecture affected ankle muscle and contact loads only slightly. The link between muscle architecture and function contributes to the understanding of the relationship between muscle structure and function