Local u'g'r'i'z' Standard Stars in the Chandra Deep Field-South

Because several observing programs are underway in various spectral regimes to explore the Chandra Deep Field South (CDF-S), the value of local photometric standards is obvious. As part of an NOAO Surveys Program to establish u'g'r'i'z' standard stars in the southern hemisphere, we have observed the central region of the CDF-S to create local standards for use by other investigators using these filters. As a courtesy, we present the CDF-S standards to the public now, although the main program will not finish until mid-2005.Comment: Accepted by AJ (scheduled for October 2003 issue). 26 pages, 5 tables, 5 figures. High resolution version of Figure 7 available at http://home.fnal.gov/~dtucker/Southern_ugriz/index.htm

In Pursuit of Good & Gold: Data Observations of Employee Ownership & Impact Investment

A startup\u27s path to self-sustaining profitability is risky and hard, and most do not make it. Venture capital (VC) investors try to improve these odds with contractual terms that focus and sharpen employees\u27 incentives to pursue gold. If the employees and investors expect the startup to balance the goal of profitability with another goal - the goal of good - the risks are likely to both grow and multiply. They grow to the extent that profits are threatened, and they multiply to the extent that balancing competing goals adds a dimension to the incentive problem. In this Article, we explore contracting terms specific to impact investing funds and their portfolio companies. We observe one possible private ordering mechanism to balance and align interests to serve both goals: employee ownership. Traditional VC investments confront contracting challenges as the portfolio companies and investors balance their interests, which may not align. The VC contracting literature identifies several agency costs that contractual terms can address. Contracts can help attract the right employees, then encourage them to work, stay, and share their best ideas. But, the existing literature addresses traditional agency costs with respect to the pursuit of a single monetary goal. Impact investment funds that balance monetary goals, short-term or long, with other goals may strike a different balance in negotiating with companies. We examine how the introduction of new motivations and interests into a precarious negotiation process shapes contracting outcomes. We address this question empirically by analyzing the role of employee stock ownership in impact investment fund contracts when investing in targeted portfolio companies. That a startup\u27s employees might receive shares and options is uncontroversial. Indeed, this appears in many ways to be fundamental to today\u27s startup culture. Might impact investors mandate that employees own shares as a means to balance dual goals? That is the key question for our analysis

Boston Hospitality Review: Fall 2016

The Heart of Successful Hotels: Going Beyond the Monopoly Game Strategy By Joseph Khairallah and Andrea Foster -- Fragments of the Past By Peter Szende and Annie Holcombe -- Hospitality Branding in the Age of the Millennial By Allen Adamson and Chekitan S. Dev -- In 2017 What Will a Restaurant Actually Be? A New Taxonomy By Christopher Muller -- The Unreal Thing: Faux Heritage at Disney By Bradford Hudson -- An Insider’s Look at the 2016 Philadelphia Democratic National Convention: Hospitality and Inclusion at Work By Erin Tucker, Leora Halpern Lanz, and Juan Lesme

North American Vegetation Dynamics Observed with Multi-Resolution Satellite Data

North American vegetation has been discovered to be a net carbon sink, with atypical behavior of drawing down more carbon from the atmosphere during the past century. It has been suggested that the Northern Hemisphere will respond favorably to climate warming by enhancing productivity and reducing the impact of fossil fuel emissions into the atmosphere. Many investigations are currently underway to understand and identify mechanisms of storage so they might be actively managed to offset carbon emissions which have detrimental consequences to the functioning of ecosystems and human well being. This paper used a time series of satellite data from multiple sensors at multiple resolutions over the past thlrty years to identify and understand mechanisms of change to vegetation productivity throughout North America. We found that humans had a marked impact to vegetation growth in half of the six selected study regions which cover greater than two million km2. We found climatic influences of increasing temperatures, and longer growing seasons with reduced snow cover in the northern regions of North America with forest fire recovery in the Northern coniferous forests of Canada. The Mid-latitudes had more direct land cover changes induced by humans coupled with climatic influences such as severe drought and altered production strategies of rain-fed agriculture in the upper Midwest, expansion of irrigated agriculture in the lower Midwest, and insect outbreaks followed by subsequent logging in the upper Northeast. Vegetation growth over long time periods (20+ years) in North America appears to be associated with long term climate change but most of the marked changes appear to be associated with climate variability on decadal and shorter time scales along with direct human land cover conversions. Our results document regional land cover land use change and climatic influences that have altered continental scale vegetation dynamics in North America

MG1-688432: A Peculiar Variable System

The short period variable star MG1-688432 has been discovered to exhibit occasional extremely high energy optical outbursts as high as 10^31 joules. Outbursts are typically of several hours duration. These events are often highly structured, resembling sequential associated releases of energy. Twenty years of time sequence photometry is presented, indicating a basic sinusoidal light curve of mean period 6.65d, with some phase shifting and long-term temporal trends in amplitude and mean brightness. Spectroscopy reveals a peculiar star, best resembling a K3 subgiant that has evolved off the main sequence moderately red-ward of the giant branch. Spectroscopic and radial velocity analyses indicate a binary system orbiting its barycenter with an unseen companion to the K3IV primary. This is not an eclipsing system with the inclination of the orbit precluding eclipse by the secondary. The system is at a distance of 1.5kpc and analysis of GAIA observations leads to the conclusion that the HR diagram position of MG1-688432 is established by an intrinsic feature of the system, most likely either the stellar evolutionary state of the observed star or the presence of small (non-gray) dust within the system. Two mechanisms that might give rise to the system are 1) impacts with tidally disrupted planetary debris, and 2) magnetically induced chromospheric activity. An intriguing idea that requires further investigation suggests that the unseen companion is perhaps a white dwarf star which has encountered a planet and tidally shredded it to produce a debris and dust veil that modulates the brightness of the primary.Comment: 74 pages, 36 figures, submitted to Astrophysical Journal Supplemen

A Bright Submillimeter Source in the Bullet Cluster (1E0657--56) Field Detected with BLAST

We present the 250, 350, and 500 micron detection of bright submillimeter emission in the direction of the Bullet Cluster measured by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST). The 500 micron centroid is coincident with an AzTEC 1.1 mm point-source detection at a position close to the peak lensing magnification produced by the cluster. However, the 250 micron and 350 micron centroids are elongated and shifted toward the south with a differential shift between bands that cannot be explained by pointing uncertainties. We therefore conclude that the BLAST detection is likely contaminated by emission from foreground galaxies associated with the Bullet Cluster. The submillimeter redshift estimate based on 250-1100 micron photometry at the position of the AzTEC source is z_phot = 2.9 (+0.6 -0.3), consistent with the infrared color redshift estimation of the most likely IRAC counterpart. These flux densities indicate an apparent far-infrared luminosity of L_FIR = 2E13 Lsun. When the amplification due to the gravitational lensing of the cluster is removed, the intrinsic far-infrared luminosity of the source is found to be L_FIR <= 10^12 Lsun, consistent with typical luminous infrared galaxies.Comment: Accepted for publication in the Astrophysical Journal. Maps are available at http://blastexperiment.info

Over half of the far-infrared background light comes from galaxies at z >= 1.2

Submillimetre surveys during the past decade have discovered a population of luminous, high-redshift, dusty starburst galaxies. In the redshift range 1 <= z <= 4, these massive submillimetre galaxies go through a phase characterized by optically obscured star formation at rates several hundred times that in the local Universe. Half of the starlight from this highly energetic process is absorbed and thermally re-radiated by clouds of dust at temperatures near 30 K with spectral energy distributions peaking at 100 microns in the rest frame. At 1 <= z <= 4, the peak is redshifted to wavelengths between 200 and 500 microns. The cumulative effect of these galaxies is to yield extragalactic optical and far-infrared backgrounds with approximately equal energy densities. Since the initial detection of the far-infrared background (FIRB), higher-resolution experiments have sought to decompose this integrated radiation into the contributions from individual galaxies. Here we report the results of an extragalactic survey at 250, 350 and 500 microns. Combining our results at 500 microns with those at 24 microns, we determine that all of the FIRB comes from individual galaxies, with galaxies at z >= 1.2 accounting for 70 per cent of it. As expected, at the longest wavelengths the signal is dominated by ultraluminous galaxies at z > 1.Comment: Accepted to Nature. Maps available at http://blastexperiment.info