WISE J104915.57-531906.1 is the nearest brown dwarf binary to our solar system, consisting of two brown dwarfs in the L/T transition: Luhman 16A and B. In this paper, we present the first map of Luhman 16A, and maps of Luhman 16B for two epochs. Our maps were created by applying Aeolus, a Markov-Chain Monte Carlo code that maps the top-of-the-atmosphere (TOA) structure of brown dwarf and other ultracool atmospheres, to light curves of Luhman 16A and B using the Hubble Space Telescope's G141 and G102 grisms. Aeolus retrieved three or four spots in the TOA of Luhman 16A and B, with a surface coverage of 19%-32% (depending on an assumed rotational period of 5 hr or 8 hr) or 21%-38.5% (depending on the observational epoch), respectively. The brightness temperature of the spots of the best-fit models was similar to 200 K hotter than the background TOA. We compared our Luhman 16B map with the only previously published map. Interestingly, our map contained a large TOA spot that was cooler (Delta T similar to 51 K) than the background, which lay at low latitudes, in agreement with the previous Luhman 16B map. Finally, we report the detection of a feature reappearing in Luhman 16B light curves that are separated by tens of hundreds of rotations from each other. We speculate that this feature is related to TOA structures of Luhman 16B.

Previous measurements of heat redistribution efficiency (the ability to transport energy from a planet's highly irradiated dayside to its eternally dark nightside) show considerable variation between exoplanets. Theoretical models predict a positive correlation between heat redistribution efficiency and temperature for tidally locked planets; however, recent Hubble Space Telescope (HST) WASP-43b spectroscopic phase curve results are inconsistent with current predictions. Using the Spitzer Space Telescope, we obtained a total of three phase curve observations of WASP-43b (P = 0.813 days) at 3.6 and 4.5. mu m. The first 3.6. mu m visit exhibits spurious nightside emission that requires invoking unphysical conditions in our cloud-free atmospheric retrievals. The two other visits exhibit strong day-night contrasts that are consistent with the HST data. To reconcile the departure from theoretical predictions, WASP-43b would need to have a high-altitude, nightside cloud/haze layer blocking its thermal emission. Clouds/hazes could be produced within the planet's cool, nearly retrograde mid-latitude flows before dispersing across its nightside at high altitudes. Since mid-latitude flows only materialize in fast-rotating (less than or similar to 1 day) planets, this may explain an observed trend connecting measured day-night contrast with planet rotation rate that matches all current Spitzer phase curve results. Combining independent planetary emission measurements from multiple phases, we obtain a precise dayside hemisphere H2O abundance (2.5 x 10(-5)-1.1 x 10(-4) at 1 sigma confidence) and, assuming chemical equilibrium and a scaled solar abundance pattern, we derive a corresponding metallicity estimate that is consistent with being solar (0.4-1.7). Using the retrieved global CO+CO2 abundance under the same assumptions, we estimate a comparable metallicity of 0.3-1.7x solar. This is the first time that precise abundance and metallicity constraints have been determined from multiple molecular tracers for a transiting exoplanet.

Samples including surface sediments and seawaters were collected from eighteen ports of Pingtung County. The objective of this study were to understand sources of organotin pollution and to monitor the organotin pollution of these fishing ports by analying with gas chromatography-flame photometric detection (GC-FPD). ¡@The results showed that butyltins were the major components of organotin pollution of the fishing ports investigated. The concentrations of MBT, DBT, TBT and MPT in seawaters varied between 3.9~51.6 ng/L as tin, ND~15.2 ng/L as tin, ND~23.9 ng/L as tin and 2.1~7.2 ng/L as tin. The concentrations of MBT, DBT, TBT and MPT in surface sediments varied between 67~332 ng/g as tin, 17.6~325 ng/g as tin, 26~420 ng/g as tin and ND~43.7 ng/g as tin. ¡@The contents of organotin compounds were relevant to the number of fishing craft and the frequency of fishery activities. Distribution of organotin compounds between seawaters and surface sediments in these fishing ports were correlational. Phenyltin was detected only in a few ports, probably due to the sewage discharge from the nearby villages. The concentrations of organotin compounds observed in this study are lower than most of the reported values from foreign ports. In comparison with the previous studies in the same areas, organotin concentrations have dropped significantly. These observations are attributed to the effective control over the utilization of organotin compounds by the authorities.

Accurate measurement of stallion spermatozoal concentration is important to equine breeding operations. The hemacytometer is considered the standard for measuring spermatozoal concentration but is time consuming and may be imprecise. The flow cytometer is considered precise and accurate, but only practical for research purposes due to sample preparation time and high cost. Photometric systems are commonly used but can be inaccurate outside a relatively narrow concentration range and can be rendered inaccurate in the presence of contaminants. A new instrument, the NucleoCounter SP-100 is reported to enumerate spermatozoa at wider concentration ranges and can identify spermatozoa in opaque semen extenders. Epididymal, neat (raw) ejaculates, and ejaculates diluted in various semen extenders were analyzed with the NucleoCounter, the Densimeter, the Spermacue, flow cytometric and hemacytometric methods. Results were compared statistically by: 1) regression analysis, 2) the agreement of two instruments, whereby the difference in values between two instruments was plotted on the y-axis against the mean of those values on the x-axis [26] and 3) a modified method that measured the percentage deviation, whereby the percentage (of the difference in values between two instruments divided by the mean) of the same two values was plotted on the y-axis against the mean value of the two instruments on the x-axis. The NucleoCounter showed more agreement with both the flow cytometer and hemacytometer for epididymal, neat ejaculated and extended spermatozoa over a range of concentrations than the Densimeter or the Spermacue. The NucleoCounter showed more agreement with the flow cytometer for epididymal and neat ejaculated spermatozoa and more agreement with the hemacytometer for spermatozoa diluted in semen extenders. The Spermacue showed the least agreement with both standards for all spermatozoal comparisons. All coefficients of variation for the flow cytometer, hemacytometer and NucleoCounter were >10% for all spermatozoal comparisons. This study indicates that the NucleoCounter shows more agreement with the flow cytometer and hemacytometer than photometric systems when evaluated with epididymal, neat ejaculated and extended spermatozoa. The instrument is also more repeatable than either photometric system, but may be cost-prohibitive for some operations.

We present results studying the distribution and properties of the diffuse dust in the Milky Way Galaxy using large optical surveys—specifically, the Sloan Digital Sky Survey (SDSS) and the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1). This work has resulted in accurate measurements of dust reddening in regions of low extinction over large regions of sky. We present maps of reddening from dust covering the footprint of the SDSS, which covers one quarter of the sky. We present preliminary maps of dust covering the Pan-STARRS1 footprint, which covers three-quarters of the sky, including most of the plane of our Galaxy. We use these maps of dust to decisively exclude some simple parameterizations of dust extinction (Cardelli et al., 1989) in favor of others (Fitzpatrick, 1999). We show that the extinction predicted by the widely-used far-infrared dust map of Schlegel et al. (1998) is overestimated by 18%, and recalibrate that map using our extinction measurements. We further map variation in the properties of the dust, as indicated by variation in the amount of extinction relative to the amout of far-infrared dust extinction, and by variation in the ratio of dust extinction at different frequencies. We confirm these results by measuring reddening using two independent techniques and data sets, the SDSS photometry and spectroscopy. We further present the photometric calibration of the Pan-STARRS1 data—a necessary step to studying the dust with that ongoing survey. We achieve photometric precision unprecedented in a large optical survey, accurate to better than 1%. We additionally show the suitability of the calibrated photometry for studying the distribution of dust. Finally, we present preliminary three-dimensional maps of the dust in the Galaxy using our calibrated data from Pan-STARRS1. These maps will provide by far the most extensive information yet achieved about the three-dimensional distribution of extinction in the Galaxy. / Physics

No description available.

Micropalaeontology, a discipline that contributes to climate research and hydrocarbon exploration, is driven by the taxonomic analysis of huge volumes of microfossils. Unfortunately, this repetitive analysis is a serious bottleneck to progress because it depends on the scarce time of experts. These issues propel research into computerized taxonomic analysis, including a promising new approach called computer-aided microfossil identification. However, the existing computer-aided system relies on image-based representations, which severely limits its ability to discriminate specimens. These limitations motivate using computer vision to support richer video and shape-based representations, which is the focus of this thesis. An important contribution is a scheme to localize, capture, and extract video and shape-based representations from large microfossil batches. These representations encapsulate information across multiple lighting conditions. In addition, the thesis describes a method based on photometric stereo to correct misalignments in images of the same object illuminated from different directions. Not only does this correction benefit the application at hand, but it can also benefit a variety of other applications. The thesis also introduces a visual-surface reconstruction method based on maximum likelihood estimation, which constructs usable depth maps even from extraordinarily noisy images. State of the art methods lack this capability. By freeing classification from the bounds imposed by images, these contributions significantly advance computerized microfossil identification toward the ultimate goal of a practical and reliable tool for high-throughput taxonomic analysis. / Digital Signals and Image Processing

We demonstrate a path to hitherto unachievable differential photometric precisions from the ground, both in the optical and near-infrared (NIR), using custom-fabricated beam-shaping diffusers produced using specialized nanofabrication techniques. Such diffusers mold the focal plane image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, imperfect guiding, and telescope-induced variable aberrations seen in defocusing. This PSF reshaping significantly increases the achievable dynamic range of our observations, increasing our observing efficiency and thus better averages over scintillation. Diffusers work in both collimated and converging beams. We present diffuser-assisted optical observations demonstrating 62(-16)(+26) ppm precision in 30 minute bins on a nearby bright star 16 Cygni A (V = 5.95) using the ARC 3.5 m telescope-within a factor of similar to 2 of Kepler's photometric precision on the same star. We also show a transit of WASP-85-Ab (V = 11.2) and TRES-3b (V = 12.4), where the residuals bin down to 180(-41)(+66) ppm in 30 minute bins for WASP-85-Ab-a factor of similar to 4 of the precision achieved by the K2 mission on this target-and to 101 ppm for TRES-3b. In the NIR, where diffusers may provide even more significant improvements over the current state of the art, our preliminary tests demonstrated 137(-36)(+64) ppm precision for a K-S = 10.8 star on the 200 inch. Hale Telescope. These photometric precisions match or surpass the expected photometric precisions of TESS for the same magnitude range. This technology is inexpensive, scalable, easily adaptable, and can have an important and immediate impact on the observations of transits and secondary eclipses of exoplanets.

We use the deep CANDELS observations in the GOODS North and South fields to revisit the correlations between stellar mass (M-*), star formation rate (SFR) and morphology, and to introduce a fourth dimension, the mass-weighted stellar age, in galaxies at 1.2 < z < 4. We do this by making new measures of M-*, SFR, and stellar age thanks to an improved SED fitting procedure that allows various star formation history for each galaxy. Like others, we find that the slope of the main sequence (MS) of star formation in the (M-*; SFR) plane bends at high mass. We observe clear morphological differences among galaxies across the MS, which also correlate with stellar age. At all redshifts, galaxies that are quenching or quenched, and thus old, have high Sigma(1) (the projected density within the central 1 kpc), while younger, star-forming galaxies span a much broader range of Sigma(1), which includes the high values observed for quenched galaxies, but also extends to much lower values. As galaxies age and quench, the stellar age and the dispersion of Sigma(1) for fixed values of M* shows two different regimes: one at the low-mass end, where quenching might be driven by causes external to the galaxies; the other at the high-mass end, where quenching is driven by internal causes, very likely the mass given the low scatter of Sigma(1) (mass quenching). We suggest that the monotonic increase of central density as galaxies grow is one manifestation of a more general phenomenon of structural transformation that galaxies undergo as they evolve.

In the last decade, over a million stars were monitored to detect transiting planets. Manual interpretation of potential exoplanet candidates is labour intensive and subject to human error, the results of which are difficult to quantify. Here we present a new method of detecting exoplanet candidates in large planetary search projects that, unlike current methods, uses a neural network. Neural networks, also called 'deep learning' or 'deep nets', are designed to give a computer perception into a specific problem by training it to recognize patterns. Unlike past transit detection algorithms, deep nets learn to recognize planet features instead of relying on hand-coded metrics that humans perceive as the most representative. Our convolutional neural network is capable of detecting Earth-like exoplanets in noisy time series data with a greater accuracy than a least-squares method. Deep nets are highly generalizable allowing data to be evaluated from different time series after interpolation without compromising performance. As validated by our deep net analysis of Kepler light curves, we detect periodic transits consistent with the true period without any model fitting. Our study indicates that machine learning will facilitate the characterization of exoplanets in future analysis of large astronomy data sets.