Historical Origins of Environment Sustainability in the German Chemical Industry, 1950s-1980s

This working paper examines the growth of corporate environmentalism in the West German chemical industry between the 1950s and the 1980s. It focuses on two companies, Bayer and Henkel and traces the evolution of their environmental strategies in response to growing evidence of pollution and resulting political pressures. Although German business has been regarded as pioneering corporate environmentalism, this study reveals major commonalities between the German and American chemical industries until the 1970s, when the two German firms diverged from their American counterparts in using public relations strategies not only to contain fallout from criticism, but also as opportunities for changes in corporate culture. The working paper finds no evidence for variety of capitalism explanations why German firms should have been early in their sustainability strategies, partly because of the importance of regional as opposed to national influences, but the study is supportive of organizational sociology theories which have identified the importance of visibility in corporate green strategies

Long-term variability of AGN at hard X-rays

Variability at all observed wavelengths is a distinctive property of AGN. Hard X-rays provide us with a view of the innermost regions of AGN, mostly unbiased by absorption along the line of sight. Swift/BAT offers the unique opportunity to follow, on time scales of days to years and with a regular sampling, the 14-195 keV emission of the largest AGN sample available up to date for this kind of investigation. We study the amplitude of the variations, and their dependence on sub-class and on energy, for a sample of 110 radio quiet and radio loud AGN selected from the BAT 58-month survey. About 80% of the AGN in the sample are found to exhibit significant variability on months to years time scales, radio loud sources being the most variable. The amplitude of the variations and their energy dependence are incompatible with variability being driven at hard X-rays by changes of the absorption column density. In general, the variations in the 14-24 and 35-100 keV bands are well correlated, suggesting a common origin of the variability across the BAT energy band. However, radio quiet AGN display on average 10% larger variations at 14-24 keV than at 35-100 keV and a softer-when-brighter behavior for most of the Seyfert galaxies with detectable spectral variability on month time scale. In addition, sources with harder spectra are found to be more variable than softer ones. These properties are generally consistent with a variable power law continuum, in flux and shape, pivoting at energies >~ 50 keV, to which a constant reflection component is superposed. When the same time scales are considered, the timing properties of AGN at hard X-rays are comparable to those at lower energies, with at least some of the differences possibly ascribable to components contributing differently in the two energy domains (e.g., reflection, absorption).Comment: 17 pages, 11 figures, accepted for publication in A&

Multiwavelength campaign on Mrk 509: testing realistic comptonization models

Mrk 509 was observed by XMM-Newton and INTEGRAL in October/November 2009, with one observation every four days for a total of ten observations. Each observation has been fitted with a realistic thermal Comptonization model for the continuum emission. Prompted by the correlation between the UV and soft X-ray flux, we used a thermal Comptonization component for the soft X-ray excess. The UV to X-ray/gamma-ray emission of Mrk 509 can be well fitted by these components, pointing to the existence of a hot (kT ∼ 100 keV), optically-thin (τ ∼ 0.5) corona producing the primary continuum. In contrast, the soft X-ray component requires a warm (kT ∼ 1 keV), optically-thick (τ ∼ 10-20) plasma. Estimates of the amplification ratio for this warm plasma support a configuration relatively close to the “theoretical” configuration of a slab corona above a passive disk. This plasma could be the warm upper layer of the accretion disk. In contrast, the hot corona has a more photon-starved geometry. The high temperature (∼ 100 eV) of the soft-photon field entering and cooling it favors a localization of the hot corona in the inner flow. This soft-photon field could be part of the comptonized emission produced by the warm plasma

Multiwavelength campaign on Mrk 509 XII. Broad band spectral analysis

(Abridged) The simultaneous UV to X-rays/gamma rays data obtained during the multi-wavelength XMM/INTEGRAL campaign on the Seyfert 1 Mrk 509 are used in this paper and tested against physically motivated broad band models. Each observation has been fitted with a realistic thermal comptonisation model for the continuum emission. Prompted by the correlation between the UV and soft X-ray flux, we use a thermal comptonisation component for the soft X-ray excess. The UV to X-rays/gamma-rays emission of Mrk 509 can be well fitted by these components. The presence of a relatively hard high-energy spectrum points to the existence of a hot (kT~100 keV), optically-thin (tau~0.5) corona producing the primary continuum. On the contrary, the soft X-ray component requires a warm (kT~1 keV), optically-thick (tau~15) plasma. Estimates of the amplification ratio for this warm plasma support a configuration close to the "theoretical" configuration of a slab corona above a passive disk. An interesting consequence is the weak luminosity-dependence of its emission, a possible explanation of the roughly constant spectral shape of the soft X-ray excess seen in AGNs. The temperature (~ 3 eV) and flux of the soft-photon field entering and cooling the warm plasma suggests that it covers the accretion disk down to a transition radius $R_{tr}$ of 10-20 $R_g$. This plasma could be the warm upper layer of the accretion disk. On the contrary the hot corona has a more photon-starved geometry. The high temperature ($\sim$ 100 eV) of the soft-photon field entering and cooling it favors a localization of the hot corona in the inner flow. This soft-photon field could be part of the comptonised emission produced by the warm plasma. In this framework, the change in the geometry (i.e. $R_{tr}$) could explain most of the observed flux and spectral variability.Comment: 19 pages, 14 figures. Accepted for publication in A&

Sex differences in mathematics and reading achievement are inversely related: within- and across-nation assessment of 10 years of PISA data

We analyzed one decade of data collected by the Programme for International Student Assessment (PISA), including the mathematics and reading performance of nearly 1.5 million 15 year olds in 75 countries. Across nations, boys scored higher than girls in mathematics, but lower than girls in reading. The sex difference in reading was three times as large as in mathematics. There was considerable variation in the extent of the sex differences between nations. There are countries without a sex difference in mathematics performance, and in some countries girls scored higher than boys. Boys scored lower in reading in all nations in all four PISA assessments (2000, 2003, 2006, 2009). Contrary to several previous studies, we found no evidence that the sex differences were related to nations’ gender equality indicators. Further, paradoxically, sex differences in mathematics were consistently and strongly inversely correlated with sex differences in reading: Countries with a smaller sex difference in mathematics had a larger sex difference in reading and vice versa. We demonstrate that this was not merely a between-nation, but also a within-nation effect. This effect is related to relative changes in these sex differences across the performance continuum: We did not find a sex difference in mathematics among the lowest performing students, but this is where the sex difference in reading was largest. In contrast, the sex difference in mathematics was largest among the higher performing students, and this is where the sex difference in reading was smallest. The implication is that if policy makers decide that changes in these sex differences are desired, different approaches will be needed to achieve this for reading and mathematics. Interventions that focus on high-achieving girls in mathematics and on low achieving boys in reading are likely to yield the strongest educational benefits

The reprocessing features in the X-ray spectrum of the NELG MCG-5-23-16

We present results from the spectral analysis of the Seyfert 1.9 galaxy MCG-5-23-16, based on ASCA, BeppoSAX, Chandra and XMM-Newton observations. The spectrum of this object shows a complex iron Kalpha emission line, which is best modeled by a superposition of a narrow and a broad (possibly relativistic) iron line, together with a Compton reflection component. Comparing results from all (six) available observations, we do not find any significant variation in the flux of both line components. The moderate flux continuum variability (about 25% difference between the brightest and faintest states), however, does not permit us to infer much about the location of the line-emitting material. The amount of Compton reflection is lower than expected from the total iron line EW, implying either an iron overabundance or that one of the two line components (most likely the narrow one) originates in Compton-thin matter.Comment: Accepted for publication in A&

BeppoSAX view of NGC 526A: a Seyfert 1.9 galaxy with a flat spectrum

In the present work we report the BeppoSAX observation of the Seyfert 1.9 galaxy NGC 526A in the band 0.1-150 keV. The high energy instrument onboard, PDS, has succeeded in measuring for the first time the spectrum of this source in the 13-150 keV range. The combined analysis of all Narrow Field Instruments provides a power law spectral index of ~ 1.6 and confirms the flat spectral nature of this source. Although NGC 526A varies strongly in the 2-10 keV over period of months/years, its spectral shape remains constant over these timescales. An Fe K-alpha line, characterized by a complex structure, has been detected in the 6-7 keV range. The line, which has an equivalent width of 120 eV, is not compatible with being produced in an absorbing torus with N_H ~ 10^22 cm^-2, but most likely originates by reflection in an accretion disk viewed at an intermediate inclination angle of ~ 42 deg. The reflection component is however small (R < 0.7) and so it is not sufficient to steepen the spectrum to photon index values more typical of AGNs. Instead, we find that the data are more consistent with a flat power law spectrum cut-off at around 100 keV plus a small reflection component which could explain the observed iron line. Thus NGC 526A is the only bona-fide Seyfert 2 galaxy which maintains a "flat spectrum" even when broad band data are considered: in this sense its properties, with respect to the general class of Seyfert 2's, are analogous to those of NGC 4151 with respect to the vast majority of Seyfert 1's.Comment: 8 pages, 6 PostScript figures, Latex manuscript, new A&A file style included, accepted for publication on Astronomy and Astrophysic

Multiwavelength campaign on Mrk 509. I. Variability and spectral energy distribution

(Abridged) Active galactic nuclei show a wealth of interesting physical processes, some of which are poorly understood. We want to address a number of open questions, including the location and physics of the outflow from AGN, the nature of the continuum emission, the geometry and physical state of the X-ray broad emission line region, the Fe-K line complex, the metal abundances of the nucleus and finally the interstellar medium of our own Galaxy. We study one of the best targets for these aims, the Seyfert 1 galaxy Mrk 509 with a multiwavelength campaign using five satellites (XMM-Newton, INTEGRAL, Chandra, HST and Swift) and two ground-based facilities (WHT and PAIRITEL). Our observations cover more than five decades in frequency, from 2 um to 200 keV. The combination of high-resolution spectroscopy and time variability allows us to disentangle and study the different components. Our campaign covers 100 days from September to December 2009, and is centred on a simultaneous set of deep XMM-Newton and INTEGRAL observations with regular time intervals, spanning seven weeks. We obtain a continuous light curve in the X-ray and UV band, showing a strong, up to 60% flux increase in the soft X-ray band during the three weeks in the middle of our deepest monitoring campaign, and which is correlated with an enhancement of the UV flux. This allows us to study the time evolution of the continuum and the outflow. By stacking the observations, we have also obtained one of the best X-ray and UV spectra of a Seyfert galaxy ever obtained. In this paper we also study the effects of the spectral energy distribution (SED) that we obtained on the photo-ionisation equilibrium. Thanks to our broad-band coverage, uncertainties on the SED do not strongly affect the determination of this equilibrium.Comment: 10 pages, 5 figures, 2 tables. Accepted for publication in Astronomy & Astrophysic