A Calibrated Measurement of the Near-IR Continuum Sky Brightness Using Magellan/FIRE

We characterize the near-IR sky background from 308 observations with the FIRE spectrograph at Magellan. A subset of 105 observations selected to minimize lunar and thermal effects gives a continuous, median spectrum from 0.83 to 2.5 microns which we present in electronic form. The data are used to characterize the broadband continuum emission between atmospheric OH features and correlate its properties with observing conditions such as lunar angle and time of night. We find that the moon contributes significantly to the inter-line continuum in the Y and J bands whereas the observed H band continuum is dominated by the blended Lorentzian wings of multiple OH line profiles even at R=6000. Lunar effects may be mitigated in Y and J through careful scheduling of observations, but the most ambitious near-IR programs will benefit from allocation during dark observing time if those observations are not limited by read noise. In Y and J our measured continuum exceeds space-based average estimates of the Zodiacal light, but it is not readily identified with known terrestrial foregrounds. If further measurements confirm such a fundamental background, it would impact requirements for OH-suppressed instruments operating in this regime.Comment: 25 pages, 11 figures, accepted to PAS

Near-Infrared InGaAs Detectors for Background-limited Imaging and Photometry

Originally designed for night-vision equipment, InGaAs detectors are beginning to achieve background-limited performance in broadband imaging from the ground. The lower cost of these detectors can enable multi-band instruments, arrays of small telescopes, and large focal planes that would be uneconomical with high-performance HgCdTe detectors. We developed a camera to operate the FLIR AP1121 sensor using deep thermoelectric cooling and up-the-ramp sampling to minimize noise. We measured a dark current of 163$~e$- s$^{-1}$ pix$^{-1}$, a read noise of 87$~e$- up-the-ramp, and a well depth of 80k$~e$-. Laboratory photometric testing achieved a stability of 230 ppm hr$^{-1/2}$, which would be required for detecting exoplanet transits. InGaAs detectors are also applicable to other branches of near-infrared time-domain astronomy, ranging from brown dwarf weather to gravitational wave follow-up.Comment: Submitted to Proc. SPIE, Astronomical Telescopes + Instrumentation (2014

Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry

We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (<1 m) telescopes capable of precise (<1 mmag) infrared photometry of relatively bright targets. The camera is constructed around the 640x512 pixel APS640C sensor built by FLIR Electro-Optical Components. We designed custom analog-to-digital electronics for maximum stability and minimum noise. The InGaAs dark current halves with every 7 deg C of cooling, and we reduce it to 840 e-/s/pixel (with a pixel-to-pixel variation of +/-200 e-/s/pixel) by cooling the array to -20 deg C. Beyond this point, glow from the readout dominates. The single-sample read noise of 149 e- is reduced to 54 e- through up-the-ramp sampling. Laboratory testing with a star field generated by a lenslet array shows that 2-star differential photometry is possible to a precision of 631 +/-205 ppm (0.68 mmag) hr^-0.5 at a flux of 2.4E4 e-/s. Employing three comparison stars and de-correlating reference signals further improves the precision to 483 +/-161 ppm (0.52 mmag) hr^-0.5. Photometric observations of HD80606 and HD80607 (J=7.7 and 7.8) in the Y band shows that differential photometry to a precision of 415 ppm (0.45 mmag) hr^-0.5 is achieved with an effective telescope aperture of 0.25 m. Next-generation InGaAs detectors should indeed enable Poisson-limited photometry of brighter dwarfs with particular advantage for late-M and L types. In addition, one might acquire near-infrared photometry simultaneously with optical photometry or radial velocity measurements to maximize the return of exoplanet searches with small telescopes.Comment: Accepted to PAS

Treating depression: Psychiatric consultation in cardiology

Depression is the most common psychiatric disorder in coronary artery disease, and it can worsen cardiac outcomes. Also, cardiac disease predisposes patients to the development of depression. Assessment of depression is an important part of ongoing patient contacts. It can be easily done through the regular use of a self-report screening tool and the clinical interview. Treatment can consist of antidepressant use, psychotherapy and mindfulness-based group therapy. The antidepressants known as the selective serotonin reuptake inhibitors can generally be used safely in cardiac patients. They are a mainstay in the treatment of moderate to severe depression. Individual cognitive-behavioral therapy can treat milder forms of depression and can augment antidepressant use in more severe cases. Mindfulness-based group therapy can provide patients with additional means of handling distress while offering social contact and support, both of which are important in the treatment of depression. The use of consulting psychiatric services offers the cardiologist a collaborative team approach when treating patients with depressive illnesses

Background-Limited Imaging in the Near-Infrared with Warm InGaAs Sensors: Applications for Time-Domain Astronomy

We describe test observations made with a customized 640 x 512 pixel Indium Gallium Arsenide (InGaAs) prototype astronomical camera on the 100" DuPont telescope. This is the first test of InGaAs as a cost-effective alternative to HgCdTe for research-grade astronomical observations. The camera exhibits an instrument background of 113 e-/sec/pixel (dark + thermal) at an operating temperature of -40C for the sensor, maintained by a simple thermo-electric cooler. The optical train and mechanical structure float at ambient temperature with no cold stop, in contrast to most IR instruments which must be cooled to mitigate thermal backgrounds. Measurements of the night sky using a reimager with plate scale of 0.4 arc seconds / pixel show that the sky flux in Y is comparable to the dark current. At J the sky brightness exceeds dark current by a factor of four, and hence dominates the noise budget. The sensor read noise of ~43e- falls below sky+dark noise for exposures of t>7 seconds in Y and 3.5 seconds in J. We present test observations of several selected science targets, including high-significance detections of a lensed Type Ia supernova, a type IIb supernova, and a z=6.3 quasar. Deeper images are obtained for two local galaxies monitored for IR transients, and a galaxy cluster at z=0.87. Finally, we observe a partial transit of the hot JupiterHATS34b, demonstrating the photometric stability required over several hours to detect a 1.2% transit depth at high significance. A tiling of available larger-format sensors would produce an IR survey instrument with significant cost savings relative to HgCdTe-based cameras, if one is willing to forego the K band. Such a camera would be sensitive for a week or more to isotropic emission from r-process kilonova ejecta similar to that observed in GW170817, over the full 190 Mpc horizon of Advanced LIGO's design sensitivity for neutron star mergers.Comment: 13 pages, 12 figures, submitted to A

Expanding Access to Consumer Health Information: A Multi-Institutional Collaboration

A partnership between an academic library, a public library system, and an area health education center meet a critical information need in a rural region of southeast Georgia

THE IDENTIFICATION OF z -DROPOUTS IN PAN-STARRS1: THREE QUASARS AT 6.5< z < 6.7

Luminous distant quasars are unique probes of the high-redshift intergalactic medium (IGM) and of the growth of massive galaxies and black holes in the early universe. Absorption due to neutral hydrogen in the IGM makes quasars beyond a redshift of z ≃ 6.5 very faint in the optical z band, thus locating quasars at higher redshifts requires large surveys that are sensitive above 1 micron. We report the discovery of three new z > 6.5 quasars, corresponding to an age of the universe of 6.5 quasars from four to seven. The quasars have redshifts of z = 6.50, 6.52, and 6.66, and include the brightest z-dropout quasar reported to date, PSO J036.5078 + 03.0498 with M[subscript 1450] = -27.4. We obtained near-infrared spectroscopy for the quasars, and from the Mg ii line, we estimate that the central black holes have masses between 5 × 10[superscript 8] and 4 × 10[superscript 9] M[subscript ʘ] and are accreting close to the Eddington limit (L[subscript Bol]/L[subscript Edd] = 0.13 - 1.2). We investigate the ionized regions around the quasars and find near-zone radii of R[subscript NZ] = 1.5 - 5.2 proper Mpc, confirming the trend of decreasing near-zone sizes with increasing redshift found for quasars at 5.7 < z < 6.4. By combining R[subscript NZ] of the PS1 quasars with those of 5.7 < z < 7.1 quasars in the literature, we derive a luminosity-corrected redshift evolution of R[subscript NZ,corrected] = (7.2 ± 0.2) - (6.1 ± 0.7) x (z - 6) Mpc. However, the large spread in R[subscript NZ] in the new quasars implies a wide range in quasar ages and/or a large variation in the neutral hydrogen fraction along different lines of sight.National Science Foundation (U.S.) (Grant AST-1109915

Plasma Leptin Levels and Incidence of Heart Failure, Cardiovascular Disease, and Total Mortality in Elderly Individuals

OBJECTIVE: Obesity predisposes individuals to congestive heart failure (CHF) and cardiovascular disease (CVD). Leptin regulates energy homeostasis, is elevated in obesity, and influences ventricular and vascular remodeling. We tested the hypothesis that leptin levels are associated with greater risk of CHF, CVD, and mortality in elderly individuals. RESEARCH DESIGN AND METHODS: We evaluated 818 elderly (mean age 79 years, 62% women) Framingham Study participants attending a routine examination at which plasma leptin was assayed. RESULTS: Leptin levels were higher in women and strongly correlated with BMI (P < 0.0001). On follow-up (mean 8.0 years), 129 (of 775 free of CHF) participants developed CHF, 187 (of 532 free of CVD) experienced a first CVD event, and 391 individuals died. In multivariable Cox regression models adjusting for established risk factors, log-leptin was positively associated with incidence of CHF and CVD (hazard ratio [HR] per SD increment 1.26 [95% CI 1.03–1.55] and 1.28 [1.09–1.50], respectively). Additional adjustment for BMI nullified the association with CHF (0.97 [0.75–1.24]) but only modestly attenuated the relation to CVD incidence (1.23 [1.00–1.51], P = 0.052). We observed a nonlinear, U-shaped relation between log-leptin and mortality (P = 0.005 for quadratic term) with greater risk of death evident at both low and high leptin levels. CONCLUSIONS: In our moderate-sized community-based elderly sample, higher circulating leptin levels were associated with a greater risk of CHF and CVD, but leptin did not provide incremental prognostic information beyond BMI. Additional investigations are warranted to elucidate the U-shaped relation of leptin to mortality.National Institutes of Health's National Heart, Lung, and Blood Institute (N01-HC25195, N01-HV28178, K24-HL04334, R01-DK080739

Constraints on Type Ia Supernova Progenitor Companions from Early Ultraviolet Observations with Swift

We compare early ultraviolet (UV) observations of Type Ia Supernovae (SNe Ia) with theoretical predictions for the brightness of the shock associated with the collision between SN ejecta and a companion star. Our simple method is independent of the intrinsic flux from the SN and treats the flux observed with the Swift/Ultra-Violet Optical Telescope (UVOT) as conservative upper limits on the shock brightness. Comparing this limit with the predicted flux for various shock models, we constrain the geometry of the SN progenitor-companion system. We find the model of a 1 M_sun red supergiant companion in Roche lobe overflow to be excluded at a 95% confidence level for most individual SNe for all but the most unfavorable viewing angles. For the sample of 12 SNe taken together, the upper limits on the viewing angle are inconsistent with the expected distribution of viewing angles for RG stars as the majority of companions with high confidence. The separation distance constraints do allow MS companions. A better understanding of the UV flux arising from the SN itself as well as continued UV observations of young SNe Ia will further constrain the possible progenitors of SNe Ia.Comment: accepted versio

Capabilities development and deployment activities in born global B-to-B firms for early entry into international markets

This paper sets out to understand how entrepreneurial founders of born global firms acquire, transform and deploy new knowledge resources for early internationalization. Adopting a dynamic capabilities view and using a sample of high-tech B-to-B firms, we report that the new firm’s early entry into international markets is executed through three transitionary phases. Founders transform the operational capabilities they endow to the firm, develop dynamic capabilities for use in opportunity exploitation, and deploy these to develop knowledge-intensive products that they take to chosen niche markets. The paper contributes to the B-to-B global marketing literature by uniting it with born global and INV internationalization research, and elucidating the three phases through which founders manage early internationalization. The roles played by entrepreneurial founders and particular capabilities are discussed