First results of the XI Groups Project: Studying an unbiased sample of galaxy groups

X-ray observations of hot, intergalactic gas in galaxy groups provide a useful means of characterizing the global properties of groups. However, X-ray studies of large group samples have typically involved very shallow X-ray exposures or have been based on rather heterogeneous samples. Here we present the first results of the XI (XMM/IMACS) Groups Project, a study targeting, for the first time, a redshift-selected, statistically unbiased sample of galaxy groups using deep X-ray data. Combining this with radio observations of cold gas and optical imaging and spectroscopy of the galaxy population, the project aims to advance the understanding of how the properties and dynamics of group galaxies relate to global group properties. Here, X-ray and optical data of the first four galaxy groups observed as part of the project are presented. In two of the groups we detect diffuse emission with a luminosity of L_X ~ 10^41 erg/s, among the lowest found for any X-ray detected group thus far, with a comparable upper limit for the other two. Compared to typical X-ray selected groups of similar velocity dispersion, these four systems are all surprisingly X-ray faint. We discuss possible explanations for the lack of significant X-ray emission in the groups, concluding that these systems are most likely collapsing for the first time. Our results strongly suggest that, unlike our current optically selected sample, previous X-ray selected group samples represented a biased picture of the group population. This underlines the necessity of a study of this kind, if one is to reach an unbiased census of the properties of galaxy groups and the distribution of baryons in the Universe.Comment: 14 pages, 8 figures, accepted for publication in MNRA

Anomalous subdiffusion with multispecies linear reaction dynamics

We have introduced a set of coupled fractional reaction-diffusion equations to model a multispecies system undergoing anomalous subdiffusion with linear reaction dynamics. The model equations are derived from a mesoscopic continuous time random walk formulation of anomalously diffusing species with linear mean field reaction kinetics. The effect of reactions is manifest in reaction modified spatiotemporal diffusion operators as well as in additive mean field reaction terms. One consequence of the nonseparability of reaction and subdiffusion terms is that the governing evolution equation for the concentration of one particular species may include both reactive and diffusive contributions from other species. The general solution is derived for the multispecies system and some particular special cases involving both irreversible and reversible reaction dynamics are analyzed in detail. We have carried out Monte Carlo simulations corresponding to these special cases and we find excellent agreement with theory

Nonsubjective priors via predictive relative entropy regret

We explore the construction of nonsubjective prior distributions in Bayesian statistics via a posterior predictive relative entropy regret criterion. We carry out a minimax analysis based on a derived asymptotic predictive loss function and show that this approach to prior construction has a number of attractive features. The approach here differs from previous work that uses either prior or posterior relative entropy regret in that we consider predictive performance in relation to alternative nondegenerate prior distributions. The theory is illustrated with an analysis of some specific examples.Comment: Published at http://dx.doi.org/10.1214/009053605000000804 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

The Volatility Trend of Protosolar and Terrestrial Elemental Abundances

We present new estimates of protosolar elemental abundances based on an improved combination of solar photospheric abundances and CI chondritic abundances. These new estimates indicate CI chondrites and solar abundances are consistent for 60 elements. We compare our new protosolar abundances with our recent estimates of bulk Earth composition (normalized to aluminium), thereby quantifying the devolatilization in going from the solar nebula to the formation of the Earth. The quantification yields a linear trend $\log(f) = \alpha\log(T_C) + \beta$, where $f$ is the Earth-to-Sun abundance ratio and $T_C$ is the 50$\%$ condensation temperature of elements. The best fit coefficients are: $\alpha = 3.676\pm 0.142$ and $\beta = -11.556\pm 0.436$. The quantification of these parameters constrains models of devolatilization processes. For example, the coefficients $\alpha$ and $\beta$ determine a critical devolatilization temperature for the Earth $T_{\mathrm{D}}(\mathrm{E}) = 1391 \pm 15$ K. The terrestrial abundances of elements with $T_{C} < T_{\mathrm{D}}(\mathrm{E})$ are depleted compared with solar abundances, whereas the terrestrial abundances of elements with $T_{C} > T_{\mathrm{D}}(\mathrm{E})$ are indistinguishable from solar abundances. The terrestrial abundance of Hg ($T_C$ = 252 K) appears anomalously high under the assumption that solar and CI chondrite Hg abundances are identical. To resolve this anomaly, we propose that CI chondrites have been depleted in Hg relative to the Sun by a factor of $13\pm7$. We use the best-fit volatility trend to derive the fractional distribution of carbon and oxygen between volatile and refractory components ($f_\mathrm{vol}$, $f_\mathrm{ref}$). We find ($0.91\pm 0.08$, $0.09 \pm 0.08$) for carbon and ($0.80 \pm 0.04$, $0.20 \pm 0.04$) for oxygen.Comment: Accepted for publication in Icarus. 28 pages, 12 figures, 5 tables. Compared to v1, the results and conclusion are the same, while discussion of results and implications is expanded considerabl

Investigation in optimisation of accuracy with non-contact systems by influencing variable processes

The use of 3D scanning systems is becoming increasingly popular and an essential tool for manufacturers for inspection and measurement. With such systems being utilised on the manufacturing shop floor due to their portability and ease of use, it is no doubt that such systems are designed to address a variety of users whom, with minimal training can operate the equipment. Due to continuing demands of high-quality products there is the need for manufacturers of 3D scanning systems to develop technologies that deliver fast and accurate information. However, one of the key challenges lies not in the training of people to use the equipment, but to develop engineers who can produce traceable, accurate and precise results with a declared statement of confidence quantifying the quality of the measurement. This statement of the quality of the output results relies on employing a set of workflow actions that involve planning, capture, processing and analysis, and finally output. This paper sets out to show how the results from a set of workflow actions from different categories of 3D scanning devices affects the quality of output

The Share Price Effects of Dividend Taxes and Tax Imputation Credits

We examine the hypothesis that dividend taxes are capitalized into share prices by focusing on investors' implicit valuations of retained earnings versus paid-in equity. Retained earnings are distributable as taxable dividends, whereas paid-in equity is distributable as a tax-free return of capital. Consistent with dividend tax capitalization, firm-level results for the United States indicate that accumulated retained earnings are valued less per unit than contributed capital. In addition, differences in dividend tax rates across U.S. tax regimes are associated with predictable differences in the magnitude of the implied tax discount for retained earnings, as are differences in dividend tax rates across Australia, Japan, France, Germany, and the United Kingdom.

Predicting the Adoption of Digital Printing in the Label Printing Industry: A Reasoned Action Study

The package printing industry is a vibrant and growing industry and digital printing technology is improving quickly--yet the adoption of digital printing has not fully penetrated the label printing market, a subset of packaging, and digital printing has seen slower adoption in its decade-long history in labels than expected. This research attempts to explain why this may be the case by understanding the factors affecting the intention to adopt digital printing. This study utilizes Fishbein and Ajzen\u27s Theory of Planned Behavior (TPB) in a cross-sectional survey of individuals in a decision-making role in label printing companies. The study was intended to gather timely, descriptive information to understand the adoption of digital printing for commercial production in the label printing industry in the next 12 months. The study attempts to measure a dependent variable, the Intention to adopt and the following independent variables: Attitude, Subjective Norm, and Perceived Behavioral Control. Questionnaire instruments were mailed to 260 companies, of which 51 responded, a response rate of nearly 19%, and of those, 31 qualified for data analysis. A high percentage (86%) of the respondents represented companies with fewer than 50 employees. The results of the research indicate that the outlook on digital printing technologies remains optimistic, however, those in charge of the adoption are concerned about budget within the next 12 months. The customer, sales, and marketing are the most influential groups supporting the adoption, contrasted with the president, and owners/shareholders with the most reserved view. The normative referents in the organization were shown to have the highest degree of influence and effect on Intention, illustrating the clarity of that construct in this specific research context. The discussion of the results covers three themes relevant to digital adoption in labels: budgetary concerns, customer-driven demands, and optimization of the production of sold goods

Life Cycle Assessment as a Tool for Green Manufacturing Education

The design and production of engineering products that have a reduced impact on the environment and human health has increasingly become a strategic goal of corporations. Consequently, starting engineers will need to be educated in green design techniques. One method that is particularly attractive to engineers is Life Cycle Assessment (LCA). LCA is an objective approach to evaluating the environmental burden of a product, process or activity by identifying and quantifying material and energy usage and waste outputs at every life stage. LCA involves three steps: identification of scope of analysis, life cycle inventory, and impact analysis. Such an approach has two attractive features for engineers. First, it is a rational and quantitative process that is easily appreciated by engineers. Second, because it examines all stages of the life cycle, it allows engineers to easily identify what design or process improvements will lead to the greatest reduction in environmental impact. The present paper will describe a laboratory experience used in a senior level materials and process selection design course developed by the author. The project involves conducting a LCA analysis on a telephone as part of a redesign of the phone to reduce its environmental impact. Students begin the project by dismantling the phone and taking inventory of the materials contained within the phone. This information is used to determine the energy consumed in production of the phone. Information is also provided regarding energy consumption in the distribution, use and disposal of the phone. Students are then asked to examine a variety of different design and process changes and determine the relative change in environmental impact resulting from these changes. The paper will discuss the LCA approach (including streamlined LCA), details of the laboratory project, student outcomes and suggestions for improving the project