The Starburst Nature of Lyman-Break Galaxies: Testing UV Extinction with X-rays

We derive the bolometric to X-ray correlation for a local sample of normal and starburst galaxies and use it, in combination with several UV reddening schemes, to predict the 2--8 keV X-ray luminosity for a sample of 24 Lyman-break galaxies in the HDF/CDF-N. We find that the mean X-ray luminosity, as predicted from the Meurer UV reddening relation for starburst galaxies, agrees extremely well with the Brandt stacking analysis. This provides additional evidence that Lyman-break galaxies can be considered as scaled-up local starbursts and that the locally derived starburst UV reddening relation may be a reasonable tool for estimating the UV extinction at high redshift. Our analysis shows that the Lyman-break sample can not have far-IR to far-UV flux ratios similar to nearby ULIGs, as this would predict a mean X-ray luminosity 100 times larger than observed, as well as far-IR luminosities large enough to be detected in the sub-mm. We calculate the UV reddening expected from the Calzetti effective starburst attenuation curve and the radiative transfer models of Witt & Gordon for low metallicity dust in a shell geometry with homogeneous or clumpy dust distributions and find that all are consistent with the observed X-ray emission. Finally, we show that the mean X-ray luminosity of the sample would be under predicted by a factor of 6 if the the far-UV is unattenuated by dust.Comment: 7 pages, 3 figures. Accepted for publication in A

Fisheries and Marine Officers recreational fishing survey: 1998/99 – 2009/10

Throughout Western Australia Fisheries and Marine Officers (FMOs) play a vital role in ensuring the sustainability of fish resources. Since July 1998, in the course of their other compliance activities, FMOs have collected information from recreational fishers on their catch and fishing trip. The primary objective of this report was to summarise the data collected by FMOs and ascertain the effectiveness of the convenience (i.e. unstructured) sampling technique for determining trends in recreational fishing patterns throughout Western Australia. Recreational fishing data was collected by FMOs during 6 629 land-based and boat-based patrols completed between 1998/99 – 2009/10, mostly within the West Coast bioregion

Physiological Response to Feeding in Little Penguins

© 2006 by The University of Chicago.Specific dynamic action (SDA), the increase in metabolic rate above resting levels that accompanies the processes of digestion and assimilation of food, can form a substantial part of the daily energy budget of free-ranging animals. We measured heart rate (fH) and rate of oxygen consumption ( ) in 12 little penguins while they digested a meal of sardines in order to determine whether they show specific dynamic action. In contrast to some studies of other penguin species, little penguins showed a substantial SDA, the magnitude of which was proportional to the size of the meal. The energy utilized in SDA was equivalent to 13.4% of the available energy content of the fish. Furthermore, animals such as penguins that forage in a cold environment will probably expend further energy in heating their food to body temperature to facilitate efficient digestion. It is estimated that this additional energy expenditure was equivalent to 1.6%-2.3% of the available energy content of the fish, depending on the time of year and therefore the temperature of the water. Changes in fH during digestion were qualitatively similar to those in , implying that there were no substantial circulatory adjustments during digestion and that the relationship between fH and in penguins is unaffected by digestive state

Optically Pumped Electron Spin Filter

This paper reports the first experimental demonstration of an optically pumped electron spin filter. Unpolarized electrons produced in a cold-cathode discharge drift through a mixture of spin-polarized Rb and a nitrogen or helium buffer gas. Through spin-exchange collisions with the Rb, the drifting electrons become polarized along the optical pumping axis. We study the role of the buffer gas in both the optical pumping and the spin transfer to the free electrons. This spin filter produces electron beams with currents and polarizations comparable to first-generation GaAs polarized electron sources

From NCLB to ESSA: Implications for Teacher Preparation and Policy

With the 2001 reauthorization of the Elementary and Secondary Education Act (ESEA), the term highly qualified teacher (HQT) became an important component of teacher licensure, including for special educators. However, when ESEA was reauthorized in 2015 as the Every Student Succeeds Act (ESSA), the highly qualified regulations were removed. The purpose of this study was to look back at the historical record of policy implementation of HQT and compare the record across states to provide implications for teacher preparation and licensure policy in the era of ESSA. This was accomplished through a review of the history of special education teacher licensure and completion of a comprehensive analysis of state licensure requirements under the Individuals with Disabilities Education Improvement Act. Despite a general consistency across three domains (i.e., degree, examination, and licensure) of the highly qualified statute, inconsistencies among states at both the elementary and secondary levels of special educator licensure may yield significant challenges related to the impact of teacher quality on student outcomes. Better understanding of these challenges is important as policymakers will be better able to make decisions regarding what teachers need to know prior to entering the field to meet students’ needs and generate student achievement

Low-Mach-number turbulence in interstellar gas revealed by radio polarization gradients

The interstellar medium of the Milky Way is multi-phase, magnetized and turbulent. Turbulence in the interstellar medium produces a global cascade of random gas motions, spanning scales ranging from 100 parsecs to 1000 kilometres. Fundamental parameters of interstellar turbulence such as the sonic Mach number (the speed of sound) have been difficult to determine because observations have lacked the sensitivity and resolution to directly image the small-scale structure associated with turbulent motion. Observations of linear polarization and Faraday rotation in radio emission from the Milky Way have identified unusual polarized structures that often have no counterparts in the total radiation intensity or at other wavelengths, and whose physical significance has been unclear. Here we report that the gradient of the Stokes vector (Q,U), where Q and U are parameters describing the polarization state of radiation, provides an image of magnetized turbulence in diffuse ionized gas, manifested as a complex filamentary web of discontinuities in gas density and magnetic field. Through comparison with simulations, we demonstrate that turbulence in the warm ionized medium has a relatively low sonic Mach number, M_s <~ 2. The development of statistical tools for the analysis of polarization gradients will allow accurate determinations of the Mach number, Reynolds number and magnetic field strength in interstellar turbulence over a wide range of conditions.Comment: 5 pages, 3 figures, published in Nature on 13 Oct 201

Contributors to the December Issue/Notes

Notes by Warren A. Deahl, W. J. Rafferty, Timothy M. Green, Bernard F. Grainey, and Jerome Gold

Contributors to the December Issue/Notes

Notes by Warren A. Deahl, W. J. Rafferty, Timothy M. Green, Bernard F. Grainey, and Jerome Gold

Contributors to the May Issue/Notes

Notes by William B. Lawless, Timothy M. Green, Thomas J. Mitchell, John D. Ryan, Charles Boynton, John R. Baty, and Theodore P. Frericks