7,055 research outputs found
Perceptually smooth timbral guides by state-space analysis of phase-vocoder parameters
Sculptor is a phase-vocoder-based package of programs
that allows users to explore timbral manipulation
of sound in real time. It is the product
of a research program seeking ultimately to perform
gestural capture by analysis of the sound a
performer makes using a conventional instrument.
Since the phase-vocoder output is of high dimensionality —
typically more than 1,000 channels per
analysis frame—mapping phase-vocoder output to
appropriate input parameters for a synthesizer is
only feasible in theory
NGC 1866: First Spectroscopic Detection of Fast Rotating Stars in a Young LMC Cluster
High-resolution spectroscopic observations were taken of 29 extended main
sequence turn-off (eMSTO) stars in the young (200 Myr) LMC cluster, NGC
1866 using the Michigan/Magellan Fiber System and MSpec spectrograph on the
Magellan-Clay 6.5-m telescope. These spectra reveal the first direct detection
of rapidly rotating stars whose presence has only been inferred from
photometric studies. The eMSTO stars exhibit H-alpha emission (indicative of
Be-star decretion disks), others have shallow broad H-alpha absorption
(consistent with rotation 150 km s), or deep H-alpha core
absorption signaling lower rotation velocities (150 km s ).
The spectra appear consistent with two populations of stars - one rapidly
rotating, and the other, younger and slowly rotating.Comment: 9 pages, 4 figures, Accepted for publication in ApJ Letter
Validation of a Dietary Screening Tool in a Middle-Aged Appalachian Population
Proactive nutrition screening is an effective public health strategy for identifying and targeting individuals who could benefit from making dietary improvements for primary and secondary prevention of disease. The Dietary Screening Tool (DST) was developed and validated to assess nutritional risk among rural older adults. The purpose of this study was to evaluate the utility and validity of the DST to identify nutritional risk in middle-aged adults. This cross-sectional study in middle-aged adults (45–64 year olds, n = 87) who reside in Appalachia, examined nutritional status using an online health survey, biochemical measures, anthropometry, and three representative 24-h dietary recalls. The Healthy Eating Index (HEI) was calculated to describe overall diet quality. Adults identified by the DST with a nutrition risk had lower HEI scores (50 vs. 64, p \u3c 0.001) and were much more likely to also be considered at dietary risk by the HEI (OR 11.6; 3.2–42.6) when compared to those not at risk. Those at risk had higher energy-adjusted total fat, saturated fat, and added sugar intakes and lower intakes of dietary fiber, and several micronutrients than those classified as not at risk by the DST. Similarly, the at-risk group had significantly lower serum levels of α-carotene, β-carotene, cryptoxanthin, lutein, and zeaxanthin but did not differ in retinol or methylmalonic acid compared with those not at risk. The DST is a valid tool to identify middle-aged adults with nutritional risk
Validation of a Dietary Screening Tool in a Middle-Aged Appalachian Population
Proactive nutrition screening is an effective public health strategy for identifying and targeting individuals who could benefit from making dietary improvements for primary and secondary prevention of disease. The Dietary Screening Tool (DST) was developed and validated to assess nutritional risk among rural older adults. The purpose of this study was to evaluate the utility and validity of the DST to identify nutritional risk in middle-aged adults. This cross-sectional study in middle-aged adults (45–64 year olds, n = 87) who reside in Appalachia, examined nutritional status using an online health survey, biochemical measures, anthropometry, and three representative 24-h dietary recalls. The Healthy Eating Index (HEI) was calculated to describe overall diet quality. Adults identified by the DST with a nutrition risk had lower HEI scores (50 vs. 64, p \u3c 0.001) and were much more likely to also be considered at dietary risk by the HEI (OR 11.6; 3.2–42.6) when compared to those not at risk. Those at risk had higher energy-adjusted total fat, saturated fat, and added sugar intakes and lower intakes of dietary fiber, and several micronutrients than those classified as not at risk by the DST. Similarly, the at-risk group had significantly lower serum levels of α-carotene, β-carotene, cryptoxanthin, lutein, and zeaxanthin but did not differ in retinol or methylmalonic acid compared with those not at risk. The DST is a valid tool to identify middle-aged adults with nutritional risk
Exoplanet properties from Lick, Keck and AAT
Doppler-shift measurements with a remarkable precision of Δλ/λ=3×10-9, corresponding to velocities of 1 m s-1, have been made repeatedly of 2500 stars located within 300 light years. The observed gravitational perturbations of the stars have revealed 250 orbiting planets, with 27 that cross in front of the host star, blocking a fraction of the starlight to allow measurement of the planet's mass, radius and density. Two new discoveries are the first good analog of Jupiter (HD 154345b) and the first system of five planets (55 Cancri). The predominantly eccentric orbits of exoplanets probably result from planet planet gravitational interactions or angular momentum exchange by mean-motion resonances. The planet mass distribution ranges from ~15 MJUP to as low as ~5 MEarth and rises toward lower masses as dN/dM~M-1.1. The distribution with orbital distance, a, rises (in logarithmic intervals) as dN/d log a~a+0.4. Extrapolation and integration suggests that 19% of all Sun-like stars harbor a gas-giant planet within 20 AU, but there remains considerable incompleteness for large orbits. Beyond 20 AU, the occurrence of gas-giant planets may be less than a few per cent as protoplanetary disk material there has lower densities and is vulnerable to destruction. Jupiter-mass planets occur more commonly around more massive stars than low mass stars. The transit of the Neptune-mass planet, Gliese 436b, yields a density of 1.55 g cm-3 suggesting that its interior has an iron silicate core surrounded by an envelope of water ice and an outer H He shell. Planets with masses as low as five Earth-masses may be commonly composed of iron nickel, rock and water along with significant amounts of H and He, making the term 'super-Earth' misleading. The transiting planet HD147506b has high orbital eccentricity but no significant orbital inclination to the line of sight, presenting a puzzle about its history. Its orbit together with the mean motion resonances of 4 of the 22 multi-planet systems provides further evidence for the role of planet planet interactions in shaping planetary architectures
Scallop swimming kinematics and muscle performance: modelling the effects of "within-animal" variation in temperature sensitivity
Escape behaviour was investigated in Queen scallops (Aequipecten opercularis) acclimated to 5, 10 or 15 degrees C and tested at their acclimation temperature. Scallops are active molluscs, able to escape from predators by jet-propelled swimming using a striated muscle working in opposition to an elastic hinge ligament. The first cycle of the escape response was recorded using high-speed video ( 250 Hz) and whole-animal velocity and acceleration determined. Muscle shortening velocity, force and power output were calculated using measurements of valve movement and jet area, and a simple biomechanical model. The average shortening speed of the adductor muscle had a Q(10) of 2.04, significantly reducing the duration of the jetting phase of the cycle with increased temperature. Muscle lengthening velocity and the overall duration of the clap cycle were changed little over the range 5 - 15 degrees C, as these parameters were controlled by the relatively temperature-insensitive, hinge ligament. Improvements in the average power output of the adductor muscle over the first clap cycle ( 222 vs. 139 W kg(-1) wet mass at 15 and 5 degrees C respectively) were not translated into proportional increases in overall swimming velocity, which was only 32% higher at 15 degrees C ( 0.37m s(-1)) than 5 degrees C (0.28 m s(-1))
AGB Sodium Abundances in the Globular Cluster 47 Tucanae (NGC 104)
A recent analysis comparing the [Na/Fe] distributions of red giant branch
(RGB) and asymptotic giant branch (AGB) stars in the Galactic globular cluster
NGC 6752 found that the ratio of Na-poor to Na-rich stars changes from 30:70 on
the RGB to 100:0 on the AGB. The surprising paucity of Na-rich stars on the AGB
in NGC 6752 warrants additional investigations to determine if the failure of a
significant fraction of stars to ascend the AGB is an attribute common to all
globular clusters. Therefore, we present radial velocities, [Fe/H], and [Na/Fe]
abundances for 35 AGB stars in the Galactic globular cluster 47 Tucanae (47
Tuc; NGC 104), and compare the AGB [Na/Fe] distribution with a similar RGB
sample published previously. The abundances and velocities were derived from
high resolution spectra obtained with the Michigan/Magellan Fiber System (M2FS)
and MSpec spectrograph on the Magellan-Clay 6.5m telescope. We find the average
heliocentric radial velocity and [Fe/H] values to be =-18.56 km s^-1
(sigma=10.21 km s^-1) and =-0.68 (sigma=0.08), respectively, in
agreement with previous literature estimates. The average [Na/Fe] abundance is
0.12 dex lower in the 47 Tuc AGB sample compared to the RGB sample, and the
ratio of Na-poor to Na-rich stars is 63:37 on the AGB and 45:55 on the RGB.
However, in contrast to NGC 6752, the two 47 Tuc populations have nearly
identical [Na/Fe] dispersion and interquartile range values. The data presented
here suggest that only a small fraction <20% of Na-rich stars in 47 Tuc may
fail to ascend the AGB. Regardless of the cause for the lower average [Na/Fe]
abundance in AGB stars, we find that Na-poor stars and at least some Na-rich
stars in 47 Tuc evolve through the early AGB phase. [abridged]Comment: Accepted for publication in the Astronomical Journal; 15 pages; 8
figures; 4 table
Implementation of the Combined--Nonlinear Condensation Transformation
We discuss several applications of the recently proposed combined
nonlinear-condensation transformation (CNCT) for the evaluation of slowly
convergent, nonalternating series. These include certain statistical
distributions which are of importance in linguistics, statistical-mechanics
theory, and biophysics (statistical analysis of DNA sequences). We also discuss
applications of the transformation in experimental mathematics, and we briefly
expand on further applications in theoretical physics. Finally, we discuss a
related Mathematica program for the computation of Lerch's transcendent.Comment: 23 pages, 1 table, 1 figure (Comput. Phys. Commun., in press
Low State, Phase-Resolved IR Spectroscopy of VV Puppis
We present phase-resolved low resolution and higher resolution -band
spectroscopy of the polar VV Pup. All observations were obtained when VV Pup
was in a low accretion state having a K magnitude near 15. The low resolution
observations reveal cyclotron emission in the band during some phases,
consistent with an origin near the active 30.5 MG pole on the white dwarf. The
secondary in VV Pup appears to be a normal M7V star and we find that the
and band fluxes are entirely due to this star at all orbital phases during
the low accretion state. We use our higher resolution Keck spectroscopy to
produce the first -band radial velocity curve for VV Pup. Our orbital
solution yields =414 km sec and leads to mass estimates of
M=0.730.05 M and M=0.100.02 M. We find
that the mass accretion rates during the normal low states of the polars VV
Pup, EF Eri, and EQ Cet are near 10 M yr. The fact
that \.M is not zero in low state polars indicates active secondary stars in
these binary systems, including the sub-stellar donor star present in EF Eri.Comment: Accepted in Astronomical Journal 5 figure
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