Using High-resolution Optical Spectra to Measure Intrinsic Properties of Low-mass Stars: New Properties for KOI-314 and GJ 3470

We construct high signal-to-noise "template" spectra by co-adding hundreds of spectra of nearby dwarfs spanning K7 to M4, taken with Keck/HIRES as part of the California Planet Search. We identify several spectral regions in the visible (370-800 nm) that are sensitive to the stellar luminosity and metallicity. We use these regions to develop a spectral calibration method to measure the mass, metallicity, and distance of low-mass stars, without the requirement of geometric parallaxes. Testing our method on a sample of nearby M dwarfs, we show that we can reproduce stellar masses to about 8%-10%, metallicity to ~0.15 dex, and distance to 11%. We were able to make use of HIRES spectra obtained as part of the radial velocity monitoring of the star KOI-314 to derive a new mass estimate of 0.57 ± 0.05 M_☉, a radius of 0.54 ± 0.05 R_☉, a metallicity, [Fe/H], of –0.28 ± 0.10, and a distance of 66.5 ± 7.3 pc. Using HARPS archival data and combining our spectral method with constraints from transit observations, we are also able to derive the stellar properties of GJ 3470, a transiting planet hosting M dwarf. We estimate a mass of 0.53 ± 0.05 M_☉, a radius of 0.50 ± 0.05 R_☉, a metallicity, [Fe/H], of 0.12 ± 0.12, and a distance of 29.9±_(3.4)^(3.7)pc

Sequential coronagraphic low-order wavefront control

Coronagraphs are highly sensitive to wavefront errors, with performance degrading rapidly in the presence of low-order aberrations. Correcting these aberrations at the coronagraphic focal plane is key to optimal performance. We present two new methods based on the sequential phase diversity approach of the "Fast and Furious" algorithm that can correct low-order aberrations through a coronagraph. The first, called "2 Fast 2 Furious," is an extension of Fast and Furious to all coronagraphs with even symmetry. The second, "Tokyo Drift," uses a deep learning approach and works with general coronagraphic systems, including those with complex phase masks. Both algorithms have 100% science uptime and require effectively no diversity frames or additional hardware beyond the deformable mirror and science camera, making them suitable for many high contrast imaging systems. We present theory, simulations, and preliminary lab results demonstrating their performance.Comment: 15 pages, 10 figures, AO4ELT7 conference proceeding

Frequency-sensitivity and magnitude-sensitivity in decision-making : predictions of a theoretical model-based study

We theoretically study decision-making behaviour in a model-based analysis related to binary choices with pulsed stimuli. Assuming a strong coupling between external stimulus and its internal representation, we argue that the frequency of external periodic stimuli represents an important degree of freedom in decision-making which may modulate behavioural responses. We consider various different stimulus conditions, including varying overall magnitudes and magnitude ratios as well as varying overall frequencies and frequency ratios, and different duty cycles of the pulsed stimuli. Decision time distributions, mean decision times and choice probabilities are simulated and compared for two different models—a leaky competing accumulator model and a diffusion-type model with multiplicative noise. Our results reveal an interplay between the sensitivity of the model systems to both frequency and magnitude of the stimuli. In particular, we find that periodic stimuli may shape the decision time distributions resulting from both models by resembling the frequencies of the pulsed stimuli. We obtain significant frequency-sensitive effects on mean decision time and choice probability for a range of overall frequencies and frequency ratios. Our simulation analysis makes testable predictions that frequencies comparable with typical sensory processing and decision-making timescales may influence choice and response times in perceptual decisions. A possible experimental implementation is proposed

The High-Flux Backscattering Spectrometer at the NIST Center for Neutron Research

We describe the design and current performance of the high-flux backscattering spectrometer located at the NIST Center for Neutron Research. The design incorporates several state-of-the-art neutron optical devices to achieve the highest flux on sample possible while maintaining an energy resolution of less than 1mueV. Foremost among these is a novel phase-space transformation chopper that significantly reduces the mismatch between the beam divergences of the primary and secondary parts of the instrument. This resolves a long-standing problem of backscattering spectrometers, and produces a relative gain in neutron flux of 4.2. A high-speed Doppler-driven monochromator system has been built that is capable of achieving energy transfers of up to +-50mueV, thereby extending the dynamic range of this type of spectrometer by more than a factor of two over that of other reactor-based backscattering instruments

Salmon at River\u27s End: The Role of the Estuary in the Decline and Recovery of Columbia River salmon

The continued decline of Columbia River salmon (Oncorhynchus spp.) populations has long focused concerns on habitat changes upriver, particularly the effects of large hydroelectric dams. Increasing evidence that ocean conditions strongly influence salmon production, however, has raised questions about the importance of the estuarine environment to salmon and whether the hydropower system has affected estuarine-rearing habitats. In response to Northwest Power Planning Council recommendations, we initiated a review of what is known about the effects of the hydroelectric system on the hydrology, habitats, and ecology of the Columbia River estuary. Our goal was to develop recommendations for improving estuarine conditions or to identify research that may be needed before appropriate salmon-management changes can be defined. Our review and analyses addressed four major questions: (1) What habitats and processes support native salmon populations during the estuarine phase of their life cycle? (2) Have changes to the estuary had a significant role in salmon decline? (3) What have been the impacts of flow regulation on the hydrology, habitat, and biological interactions in the estuarine ecosystem? (4) What estuarine conditions are necessary to maintain salmonid diversity in the Columbia River basin

REF 2028 initial decisions survey. UKAPA response

The four UK higher education funding bodies (Research England, SFC, HEFCW and DfE (NI) are publishing key decisions on the high-level design of the next research assessment exercise and outlining issues for further consultation. These decisions represent a shift towards a broader and more holistic approach to research assessment. This survey is hosted by Research England (part of UKRI) on behalf of the four UK funding bodies. The survey is available as a downloadable PDF for convenience (see below). This is the response from UKAPA (United Kingdom Association for Public Administration - the Learned Society for PA

Effect of Salt on Phosphorylcholine-based Zwitterionic Polymer Brushes.

A quantitative investigation of the responses of surface-grown biocompatible brushes of poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) to different types of salt has been carried out using ellipsometry, quartz crystal microbalance (QCM) measurements, and friction force microscopy. Both cations and anions of varying valency over a wide range of concentrations were examined. Ellipsometry shows that the height of the brushes is largely independent of the ionic strength, confirming that the degree of swelling of the polymer is independent of the ionic character of the medium. In contrast, QCM measurements reveal significant changes in mass and dissipation to the PMPC brush layer, suggesting that ions bind to phosphorylcholine (PC) groups in PMPC molecules, which results in changes in the stiffness of the brush layer, and the binding affinity varies with salt type. Nanotribological measurements made using friction force microscopy show that the coefficient of friction decreases with increasing ionic strength for a variety of salts, supporting the conclusion drawn from QCM measurements. It is proposed that the binding of ions to the PMPC molecules does not change their hydration state, and hence the height of the surface-grown polymeric brushes. However, the balance of the intra- and intermolecular interactions is strongly dependent upon the ionic character of the medium between the hydrated chains, modulating the interactions between the zwitterionic PC pendant groups and, consequently, the stiffness of the PMPC molecules in the brush layer

Ethnic Comparison of Weight Loss in Trial of Nonpharmacologic Interventions in the Elderly

https://onlinelibrary.wiley.com/doi/epdf/10.1038/oby.2002.1

Correspondence between Scale Morphometrics and Scale and Otolith Chemistry for Interpreting Juvenile Salmon Life Histories

Fish scales have long been used to reconstruct fine-scale habitat transitions such as the movement of juvenile fish from freshwater, estuary, and ocean environments. Despite the importance of life history information to fisheries management and conservation, few studies have validated that scale morphology accurately describes fish movement between these habitats. Therefore, we tested the accuracy of using scale morphometric criteria to identify the movement of juvenile Chinook Salmon Oncorhynchus tshawytscha from freshwater to marine portions of the Columbia River estuary by comparing scale morphometric classification, scale chemistry, and otolith chemistry. Nearly one-half of all fish collected in the saline portion of the estuary and approximately one-quarter in the freshwater portion exhibited morphometric patterns (i.e., scale checks and intermediate growth) often associated with periods of estuary rearing. Depending upon the criteria used to define scale checks, otolith chemical results indicated that 33–53% of fish would have been misclassified as estuary residents based solely on their scale patterns. Moreover, many individuals who had resided in strontium-rich estuary water did not form a visible check (37%) on their scales to coincide with estuary entry. We estimated from otolith chemistry that these fish had either entered at or near the size at which scale formation occurs (35–42 mm) or had recently migrated to the saline portion of the estuary (<30 d) before new scale material could be formed and calcified. Scale chemistry alone was a good indicator of entrance into the saline portion of the estuary. Scale chemistry responded to the strontium-enriched salt water, and explained 86% of the variation found in otolith chemistry. Scale morphometric classification did not provide the fine-scale resolution that scale and, even more so, otolith chemistry provided for describing the proportion of juvenile Chinook salmon using the saline portion of the Columbia River estuary