J0811+4730: the most metal-poor star-forming dwarf galaxy known

We report the discovery of the most metal-poor dwarf star-forming galaxy (SFG) known to date, J0811+4730. This galaxy, at a redshift z=0.04444, has a Sloan Digital Sky Survey (SDSS) g-band absolute magnitude M_g = -15.41 mag. It was selected by inspecting the spectroscopic data base in the Data Release 13 (DR13) of the SDSS. LBT/MODS spectroscopic observations reveal its oxygen abundance to be 12 + log O/H = 6.98 +/- 0.02, the lowest ever observed for a SFG. J0811+4730 strongly deviates from the main-sequence defined by SFGs in the emission-line diagnostic diagrams and the metallicity - luminosity diagram. These differences are caused mainly by the extremely low oxygen abundance in J0811$+$4730, which is ~10 times lower than that in main-sequence SFGs with similar luminosities. By fitting the spectral energy distributions of the SDSS and LBT spectra, we derive a stellar mass of M* = 10^6.24 - 10^6.29 Msun (statistical uncertainties only), and we find that a considerable fraction of the galaxy stellar mass was formed during the most recent burst of star formation.Comment: 12 pages, 5 figures, accepted for publication in MNRA

Ancient technology and punctuated change: Detecting the emergence of the Edomite Kingdom in the Southern Levant.

While the punctuated equilibrium model has been employed in paleontological and archaeological research, it has rarely been applied for technological and social evolution in the Holocene. Using metallurgical technologies from the Wadi Arabah (Jordan/Israel) as a case study, we demonstrate a gradual technological development (13th-10th c. BCE) followed by a human agency-triggered punctuated "leap" (late-10th c. BCE) simultaneously across the entire region (an area of ~2000 km2). Here, we present an unparalleled, diachronic archaeometallurgical dataset focusing on elemental analysis of dozens of well-dated slag samples. Based on the results, we suggest punctuated equilibrium provides an innovative theoretical model for exploring ancient technological changes in relation to larger sociopolitical conditions-in the case at hand the emergence of biblical Edom-, exemplifying its potential for more general cross-cultural applications

Publish, Don\u27t Perish: Experienced Authors Share Ideas

In the past. many Extension agents and specialists didn\u27t think much about publish or perish. But with everchanging university administrators and policies, Extension workers now recognize the importance of publishing in refereed journals. Because of this, communication specialists are increasingly writing joumal articles and also are being asked to help subject-matter specialists and field agents prepare articles for publishing. Information gleaned from five Oregon State University faculty shows the importance of writing only about what interests you, getting to know others in your field, deciding where to market your work, seeking constructive criticism, and developing long-range strategies for publishing

The Residual Income Approach to Housing Affordability: The Theory and the Practice

The residual income approach to housing affordability is one that looks at what different household types can afford to spend on housing after taking into account the other necessary expenditures of living. It is an alternative to benchmark measures of affordability as used in social housing rent setting in Australia (the 25% rule) or assessing the overall affordability in the wider housing market (the 30/40 rule) as commonly used by a range of housing affordability researchers in Australia. This Positioning Paper does two things. Part A provides an overview, using existing literature, of the various semantic, substantive and definitional issues around the notion of affordability, leading to an argument in support of the soundness of the residual income approach. This overview is set in the historical contexts of discussions about affordability measures in the US, UK and Australia. Part B is methodological; it shows for various household types and income ranges, both for home purchase and rental, how the residual income method can be operationalised and its potential policy applications. This is still work in progress and there may be minor refinements to the method by the time of the production of the Final Report. However, we are confident that the method is sufficiently robust at this point to indicate its substantial potential as a problem identification and policy tool

The Residual Income Method: A New Lens on Housing Affordability and Market Behaviour

This study was designed to explore the viability of an alternative method of measuring affordability (the residual income method) to that of the ubiquitous 30 per cent benchmark method and to use this alternative method for enriching understanding around a range of affordability and housing market issues. The work has been exploratory but it does reveal both the potential and the limitations of the method. Put simply, the residual income method calculates how much is left over for housing rents or mortgage after relevant expenditure items for different household types have been taken into account. If there is insufficient left for rents and mortgages after meeting this budget standard, a household has an affordability problem. The basis for formulating such a measure for Australia was enabled by the development of indicative budget standards by the Social Policy Research Centre (SPRC) at the University of New South Wales (Saunders et al. 1998). They established a low cost budget standard (LCBS) and a modest cost budget standard (MCBS); the former might be seen as a minimum level of consumption in contemporary Australia, while the latter allows for a comfortable but far from luxurious lifestyle. Both have been used in this study, but with most emphasis on the LCBS, and have been indexed to relevant years by a composite index of the CPI minus housing component and of disposable Income. This Final Report is not an exhaustive treatment of the residual income method but is designed to illustrate its potential, relative to benchmark methods, for understanding a number of housing affordability related issues. And, while the subject matter could potentially be quite technical and detailed, the report aims to minimise the detail and concentrate on understanding and exemplification. The report has a number of objectives: 1. Use the residual income method to calculate the distribution of housing affordability in Australia in aggregate and for individual household types by tenure, income, state and other relevant variables in order to get some assessment of the scale and distribution of residual income affordability. This includes comparison with the ratio method, either the aggregate 30 per cent measure or the more targeted 30/40 ratio, that is, 30 per cent for the lowest 40 per cent of income earners. 2. Compare these aggregate Australian findings with those for the USA, as representing a form of benchmark to assess how badly or well Australia performs in terms of affordability. 3. Model the affordability capacity of case study households (single person, couple with two children) across a broad income range to provide a better understanding of how affordability constraints, as indicated by the residual income method, are potentially shaping the operation of housing markets. 4. Illustrate using the Melbourne and Adelaide home purchase markets what the residual income method suggests about the performance of these housing markets in terms of affordability. 5. Illustrate using the Melbourne rental market what the residual income method suggests about the performance of this housing market and associated submarkets in terms of affordability. 6. Test the appropriateness of the residual income method for social and affordable housing rent-setting policy and eligibility practices

The Residual Income Approach to Housing Affordability: The Theory and the Practice

The residual income approach to housing affordability is one that looks at what different household types can afford to spend on housing after taking into account the other necessary expenditures of living. It is an alternative to benchmark measures of affordability as used in social housing rent setting in Australia (the 25% rule) or assessing the overall affordability in the wider housing market (the 30/40 rule) as commonly used by a range of housing affordability researchers in Australia. This Positioning Paper does two things. Part A provides an overview, using existing literature, of the various semantic, substantive and definitional issues around the notion of affordability, leading to an argument in support of the soundness of the residual income approach. This overview is set in the historical contexts of discussions about affordability measures in the US, UK and Australia. Part B is methodological; it shows for various household types and income ranges, both for home purchase and rental, how the residual income method can be operationalised and its potential policy applications. This is still work in progress and there may be minor refinements to the method by the time of the production of the Final Report. However, we are confident that the method is sufficiently robust at this point to indicate its substantial potential as a problem identification and policy tool

A Widespread, Clumpy Starburst in the Isolated Ongoing Dwarf Galaxy Merger dm1647+21

Interactions between pairs of isolated dwarf galaxies provide a critical window into low-mass hierarchical, gas-dominated galaxy assembly and the buildup of stellar mass in low-metallicity systems. We present the first VLT/MUSE optical IFU observations of the interacting dwarf pair dm1647+21, selected from the TiNy Titans survey. The H$\alpha$ emission is widespread and corresponds to a total unobscured star formation rate (SFR) of 0.44 M$_{\odot}$ yr$^{-1}$, 2.7 times higher than the SFR inferred from SDSS data. The implied specific SFR (sSFR) for the system is elevated by more than an order of magnitude above non-interacting dwarfs in the same mass range. This increase is dominated by the lower-mass galaxy, which has a sSFR enhancement of $>$ 50. Examining the spatially-resolved maps of classic optical line diagnostics, we find the ISM excitation can be fully explained by star formation. The velocity field of the ionized gas is not consistent with simple rotation. Dynamical simulations indicate that the irregular velocity field and the stellar structure is consistent with the identification of this system as an ongoing interaction between two dwarf galaxies. The widespread, clumpy enhancements in star formation in this system point to important differences in the effect of mergers on dwarf galaxies, compared to massive galaxies: rather than the funneling of gas to the nucleus and giving rise to a nuclear starburst, starbursts in low-mass galaxy mergers may be triggered by large-scale ISM compression, and thus be more distributed.Comment: Accepted for publication in ApJ. 11 pages, 5 figures, 1 table. Figures slightly degraded to meet arXiv size restrictions. For more information about TiNy Titans see https://lavinia.as.arizona.edu/~tinytitans

Effect of Fluoride and Cobalt on Forming Enamel: Scanning Electron Microscope and X-Ray Microanalysis Study

The forming surfaces of enamel of rat incisors were examined by scanning electron microscope one hour after injection of either 5 mg/100 g body weight of sodium fluoride or 12 mg/100 g body weight of cobalt chloride. The cell debris from the surfaces of the separated incisors was either gently wiped off with soft facial tissues or chemically removed by treating with NaOH, NaOCl or trypsin. Best results to remove cell debris were obtained from 0.25% trypsin treatment. SEM studies revealed that the surface of the normal secretory enamel was characteristic in appearance with well-developed smooth prism outlines. In fluoride specimens the prism outlines were feathery in appearance, laced with protruding spine-shaped clusters of mineral crystals. In the case of cobalt treatment, prism outlines were less uniform and in some areas they were incomplete. The calcium concentration of surface enamel was significantly lower in the cobalt-treated specimens than those from control and fluoride-treated animals. The Ca:Mg ratio was also lower in cobalt-treated specimens as compared to control and fluoride-treated ones