Temperature-based metallicity measurements at z=0.8: direct calibration of strong-line diagnostics at intermediate redshift

We present the first direct calibration of strong-line metallicity diagnostics at significant cosmological distances using a sample at z=0.8 drawn from the DEEP2 Galaxy Redshift Survey. Oxygen and neon abundances are derived from measurements of electron temperature and density. We directly compare various commonly used relations between gas-phase metallicity and strong line ratios of O, Ne, and H at z=0.8 and z=0. There is no evolution with redshift at high precision ($\Delta \log{\mathrm{O/H}} = -0.01\pm0.03$, $\Delta \log{\mathrm{Ne/O}} = 0.01 \pm 0.01$). O, Ne, and H line ratios follow the same locus at z=0.8 as at z=0 with $\lesssim$0.02 dex evolution and low scatter ($\lesssim$0.04 dex). This suggests little or no evolution in physical conditions of HII regions at fixed oxygen abundance, in contrast to models which invoke more extreme properties at high redshifts. We speculate that offsets observed in the [N II]/H$\alpha$ versus [O III]/H$\beta$ diagram at high redshift are therefore due to [NII] emission, likely as a result of relatively high N/O abundance. If this is indeed the case, then nitrogen-based metallicity diagnostics suffer from systematic errors at high redshift. Our findings indicate that locally calibrated abundance diagnostics based on alpha-capture elements can be reliably applied at z$\simeq$1 and possibly at much higher redshifts. This constitutes the first firm basis for the widespread use of empirical calibrations in high redshift metallicity studies.Comment: 14 pages, 10 figures, accepted to Ap

Geospatial modeling approach to monument construction using Michigan from A.D. 1000–1600 as a case study

Building monuments was one way that past societies reconfigured their landscapes in response to shifting social and ecological factors. Understanding the connections between those factors and monument construction is critical, especially when multiple types of monuments were constructed across the same landscape. Geospatial technologies enable past cultural activities and environmental variables to be examined together at large scales. Many geospatial modeling approaches, however, are not designed for presence-only (occurrence) data, which can be limiting given that many archaeological site records are presence only. We use maximum entropy modeling (MaxEnt), which works with presence-only data, to predict the distribution of monuments across large landscapes, and we analyze MaxEnt output to quantify the contributions of spatioenvironmental variables to predicted distributions. We apply our approach to co-occurring Late Precontact (ca. A.D. 1000–1600) monuments in Michigan: (i) mounds and (ii) earthwork enclosures. Many of these features have been destroyed by modern development, and therefore, we conducted archival research to develop our monument occurrence database. We modeled each monument type separately using the same input variables. Analyzing variable contribution to MaxEnt output, we show that mound and enclosure landscape suitability was driven by contrasting variables. Proximity to inland lakes was key to mound placement, and proximity to rivers was key to sacred enclosures. This juxtaposition suggests that mounds met local needs for resource procurement success, whereas enclosures filled broader regional needs for intergroup exchange and shared ritual. Our study shows how MaxEnt can be used to develop sophisticated models of past cultural processes, including monument building, with imperfect, limited, presence-only data

Support for Drought Response and Community Preparedness: Filling the Gaps between Plans and Action

This chapter examines which levels of government handle various aspects of drought, as well as interactions between levels of government, providing examples from states across the western United States. It also takes a look at aspects of drought that fall outside traditional lines of authority and disciplinary boundaries. As part of a discussion on how states support local drought response, the chapter details and contrasts how California and Colorado track public water supply restrictions, and describes Colorado’s process for incorporating input from river basins across the state into its water plan. Case studies focus on drought planning in the Klamath River and Upper Colorado River basins through the lens of collaborative environmental planning. The chapter concludes that drought planning will be more effective as more states coordinate and align goals and policies at multiple levels of government

FRAMING CRAFT AND PERFORMANCE IN HYBRID PUPPETRY WORKSHOPS

Prototyping Puppets combines craft and performance in a puppet making STEM workshop for informal learning. We report on its final evaluation in two events (n=10 and n=13) to show how the design addressed black boxing of technology through a craft-centric approach and successfully engaged different student populations through an educational framing that included performance practice. The informal learning workshops are aimed at 5th grade level students and cover CSTA and NCSS learning objectives. First, the problem space is laid out and the approach of the project introduced. Second, the design realization is briefly covered. Third, the final evaluation of the design in two workshop conditions is presented using qualitative as well as quantitative data. Students showed self-perceived   increases particularly in their attitudes toward technology. These results are discussed before we report on the adaptation of the workshop for different conditions to illustrate the flexibility of the basic set up

What Constitutes An Effective Human Resources Curriculum?

What constitutes an effective university curriculum in human resources management? In an effort to answer this question, the authors reviewed the research literature on human resources curricula, comparing, contrasting and synthesizing the recommendations that have been offered in recent studies. Although a number of scholars have addressed this issue from a variety of perspectives and offer many noteworthy points for consideration, the review of the research literature indicates that a definitive answer to the question of curriculum content has not yet been found. The authors summarize the recent research, categorizing studies in terms of type pf research (empirical versus conceptual), nature of subjects in empirical studies (executives, HR practitioners, recent graduates of HR program), gratitude versus undergraduate program focus, and focus of the course of study (professional versus educational) in order to identify the current state of knowledge and fruitful avenues for future research. They provide a useful source of information for those charged with creating and maintaining quality human resources education programs, and for those who intend to research the topic further

An Ionization Cone in the Dwarf Starburst Galaxy NGC 5253

There are few observational constraints on how the escape of ionizing photons from starburst galaxies depends on galactic parameters. Here, we report on the first major detection of an ionization cone in NGC 5253, a nearby starburst galaxy. This high-excitation feature is identified by mapping the emission-line ratios in the galaxy using [S III] lambda 9069, [S II] lambda 6716, and H_alpha narrow-band images from the Maryland-Magellan Tunable Filter at Las Campanas Observatory. The ionization cone appears optically thin, which is suggestive of the escape of ionizing photons. The cone morphology is narrow with an estimated solid angle covering just 3% of 4pi steradians, and the young, massive clusters of the nuclear starburst can easily generate the radiation required to ionize the cone. Although less likely, we cannot rule out the possibility of an obscured AGN source. An echelle spectrum along the minor axis shows complex kinematics that are consistent with outflow activity. The narrow morphology of the ionization cone supports the scenario that an orientation bias contributes to the difficulty in detecting Lyman continuum emission from starbursts and Lyman break galaxies.Comment: 5 pages, 4 figures, Accepted to ApJ Letter

The Valuation of Distressed Companies - A Conceptual Framework

It is often crucial to ascertain the value of a distressed company. Those interested in the company’s undertaking require this information to determine what should be done with the company’s business, and how the value in the company’s estate should be distributed amongst them. In this article, addressed primarily to the parties to corporate reorganisation proceedings in the UK and their advisers, we provide a conceptual framework within which these questions might be answered. The first part of the article identifies the bases on which a company’s business might be valued. Drawing upon economic theory, empirical evidence, and the sophisticated principles evolved by US courts with long experience of dealing with such issues, it explains the circumstances in which one or other of these bases might appropriately be adopted. The onset of corporate distress creates unique additional problems in attempting business valuations, whether carried out in a court context or out of court. Focusing particularly on the incentives of those interested in the outcome of reorganisation proceedings, the article seeks to distinguish between the ‘structural’ and the ‘strategic’ factors giving rise to these problems, and explains how these might impact upon the valuation process. It then draws on the US jurisprudence on business valuation to outline three methods for putting a value on a ‘going concern’. It is submitted that the principles developed by US courts will prove helpful and persuasive as UK courts grapple more and more frequently with valuation issues. The second part of the article consists of a detailed analysis of the recent judgment of the English High Court in In re MyTravel Group Plc, which is employed as a case study in the application of the conceptual framework laid down in the first part