The geometry and ionization structure of the wind in the eclipsing nova-like variables RW Tri and UX UMa

The UV spectra of nova-like variables are dominated by emission from the accretion disk, modified by scattering in a wind emanating from the disk. Here, we model the spectra of RW Tri and UX UMa, the only two eclipsing nova-like variables which have been observed with the Hubble Space Telescope in the far-ultraviolet, in an attempt to constrain the geometry and the ionization structure of their winds. Using our Monte Carlo radiative transfer code, we computed spectra for simply parameterized axisymmetric biconical outflow models and were able to find plausible models for both systems. These reproduce the primary UV resonance lines-N v, Si iv, and C iv-in the observed spectra in and out of eclipse. The distribution of these ions in the wind models is similar in both cases as is the extent of the primary scattering regions in which these lines are formed. The inferred mass-loss rates are 6%-8% of the mass accretion rates for the systems. We discuss the implication of our point models for our understanding of accretion disk winds in cataclysmic variables. © 2010. The American Astronomical Society. All rights reserved.

Momentum Trading in New York Stock Exchange (NYSE) Energy Stocks

This paper investigates whether the momentum effect exists in the NYSE energy sector. Momentum is defined as the strategy that buys (sells) these stocks that are best (worst) performers, over a pre-specified past period of time (the 'look-back' period), by constructing equally weighted portfolios. Different momentum strategies are obtained by changing the number of stocks included in these portfolios, as well as the look-back period. Next, their performance is compared against two benchmarks: the equally weighted portfolio consisting of most stocks in the NYSE energy index and the market portfolio, and the S&P500 index. The results indicate that the momentum effect is strongly present in the energy sector, and leads to highly profitable portfolios, improving the risk-reward measures and easily outperforming both benchmarks.

Air pollutant contamination and acidification of surface waters in the North York Moors, UK: Multi-proxy evidence from the sediments of a moorland pool

Despite the extensive geographical range of palaeolimnological studies designed to assess the extent of surface water acidification in the United Kingdom during the 1980s, little attention was paid to the status of surface waters in the North York Moors (NYM). In this paper, we present sediment core data from a moorland pool in the NYM that provide a record of air pollution contamination and surface water acidification. The 41-cm-long core was divided into three lithostratigraphic units. The lower two comprise peaty soils and peats, respectively, that date to between approximately 8080 and 6740 cal. BP. The uppermost unit comprises peaty lake muds dating from between approximately ad 1790 and the present day (ad 2006). The lower two units contain pollen dominated by forest taxa, whereas the uppermost unit contains pollen indicative of open landscape conditions similar to those of the present. Heavy metal, spheroidal carbonaceous particle, mineral magnetics and stable isotope analysis of the upper sediments show clear evidence of contamination by air pollutants derived from fossil-fuel combustion over the last c. 150years, and diatom analysis indicates that the naturally acidic pool became more acidic during the 20th century. We conclude that the exceptionally acidic surface waters of the pool at present (pH=c. 4.1) are the result of a long history of air pollution and not because of naturally acidic local conditions. We argue that the highly acidic surface waters elsewhere in the NYM are similarly acidified and that the lack of evidence of significant recovery from acidification, despite major reductions in the emissions of acidic gases that have taken place over the last c. 30years, indicates the continuing influence of pollutant sulphur stored in catchment peats, a legacy of over 150years of acid deposition.

Multidrug transporter proteins of the major facilitator superfamily: not only for drug efflux

Multidrug resistance in prokaryotes is due primarily to efflux of offending antimicrobials from the cell by representatives of several different families of integral membrane transporter proteins. Clearly, in evolutionary terms, these proteins did not arise specifically to pump human-made antimicrobials out of the cell and thereby confer resistance. Despite this, often only their role in antibiotic resistance is characterised and highlighted.
In recent years, however, a transition from the traditional anthropocentric perception of antibiotic resistance mechanisms in microorganisms has occurred, with naturally produced antimicrobials now generally regarded as physiologically important signalling molecules or sources of nutrition for bacteria rather than antimicrobial agents, and bacterial multidrug efflux proteins not merely as a defensive response to antimicrobials but as important players in fundamental physiological processes such as cellular homeostasis.
This emerging perspective supports the notion that a better understanding of the complexities of infection and multidrug resistance in bacteria can be achieved via a more detailed understanding of those physiological processes. In this chapter, we review the ‘true’ physiological roles of multidrug efflux proteins of the largest non-ATP-hydrolysing family of membrane transporters, the major facilitator superfamily, and explore the evidence for their function in processes such as pH and metal homeostasis, import and export of metabolites and biofilm formation

Exceptionally Long Distance Transport of Volcanic Ash: Implications for Stratigraphy, Hazards and the Sourcing of Distal Tephra Deposits

Cryptotephras (tephra not visible to the naked eye) form the foundation of the tephrostratigraphic frameworks used in Europe to date and correlate widely distributed geologic, paleoenvironmental and archaeological records. Pyne-O'Donnell et al. (2012) established the potential for developing a similar crypto-tephrostratigraphy across eastern North America by identifying multiple tephra, including the White River Ash (east; WRAe), St. Helens We and East Lake, in a peat core located in Newfoundland. Following on from this work, several ongoing projects have examined additional peat cores from Michigan, New York State, Maine, Nova Scotia and Newfoundland to build a tephrostratigraphic framework for this region. Using the precedent set by recent research by Jensen et al.(in press) that correlated the Alaskan WRAe to the European cryptotephra AD860B, unknown tephras identified in this work were not necessarily assumed to be from "expected" source areas (e.g. the Cascades). Here we present several examples of the preservation of tephra layers with an intercontinental distribution (i.e. WRAe and Ksudach 1), from relatively small magnitude events (i.e. St. Helens layer T, Mono Crater), and the first example of a Mexican ash in the NE (Volcan Ceboruco, Jala pumice). There are several implications of the identification of these units. These far-travelled ashes: (1) highlight the need to consider "ultra" distal source volcanoes for unknown cryptotephra deposits,. (2) present an opportunity for physical volcanologists to examine why some eruptions have an exceptional distribution of ash that is not necessarily controlled by the magnitude of the event. (3) complicate the idea of using tephrostratigraphic frameworks to understand the frequency of eruptions towards aiding hazard planning and prediction (e.g. Swindles et al., 2011). (4) show that there is a real potential to link tropical and mid to high-latitude paleoenvironmental records. Jensen et al. (in press) Transatlantic correlation of the Alaskan White River Ash. Geology. Pyne-O'Donnell et al. (2012). High-precision ultra-distal Holocene tephrochronology in North America. Quaternary Science Reviews, 52, 6-11. Swindles et al. (2011). A 7000 yr perspective on volcanic ash clouds affecting northern Europe. Geology, 39, 887-890.

Understanding Risk: Contributions from the Journal of Risk and Governance

During recent years, news headlines have been rife with criticisms of the risk management practices of public and private sector entities. These criticisms have often been accompanied by calls for greater transparency in the way government entities manage risks and communicate dangers to the public. Similarly, in the private sector, the internationalisation of economic activity has heightened concerns over the potential adverse implications of mismanagement and financial scandals, and has led to calls for greater regulation and supervision. While the responses of public sector agencies and private sector actors to these challenges have differed, they share a common acknowledgement that effective governance relies on the pro-active identification, assessment, and management of risks as well as appropriate regulatory frameworks.

This edited book covers a number of divergent topics illustrating the emergence of several novel themes in the area of economic and social risks. As a communality, these novel themes relate to the complexity in which human activity in this late stage of capitalist development is embedded. This risk-generating complexity, in turn, can be observed at several levels, including workplace hazards, governance problems within the private sector or the intersection between public and private, and in relation to the economic risks faced by larger entities such as national governments.

The Unusually Luminous Extragalactic Nova SN 2010U

We present observations of the unusual optical transient SN 2010U, including spectra taken 1.03 days to 15.3 days after maximum light that identify it as a fast and luminous Fe II type nova. Our multi-band light curve traces the fast decline (t 2 = 3.5 ± 0.3 days) from maximum light (MV = -10.2 ± 0.1 mag), placing SN 2010U in the top 0.5% of the most luminous novae ever observed. We find typical ejecta velocities of ≈1100 km s-1 and that SN 2010U shares many spectral and photometric characteristics with two other fast and luminous Fe II type novae, including Nova LMC 1991 and M31N-2007-11d. For the extreme luminosity of this nova, the maximum magnitude versus rate of decline relationship indicates a massive white dwarf (WD) progenitor with a low pre-outburst accretion rate. However, this prediction is in conflict with emerging theories of nova populations, which predict that luminous novae from massive WDs should preferentially exhibit an alternate spectral type (He/N) near maximum light.

Understanding Risk: Recent Contributions from the Journal of Risk and Governance

Following on from the format of the previous Book Understanding Risk: Contributions from the Journal of Risk and Governance, this collection of recent contributions (including work by the editor) this book is divided in three sections .  The first section examines issues relating to corporate governance in the private sector, with emphasis being placed on issues of 'Board Decision Making,' Earnings Management and Audit Committee Effectiveness'  and ' Corporate Governance Failures.'  These contributions are complemented by the second sections which looks at governance and risk issues affecting the public sector, with a focus being places on 'Public Private Partnerships' and regulation of activities in the Life Sciences.'  Section three focuses on societal risk management in relation to health, safety and the environment.  In this context, contributions are presented in relation to major debates surrounding 'Rising Trends in Cancer Cases,' dilemmas surrounding 'Medical Self Help,' 'Mental Health Policy' and the use of 'Information Technology in Health Care.'

Foreign Direct Investment and Country Risk::Is There Evidence of 'Malign Investment in the Former Soviet States'

This paper examines the relationship between concepts of MNE bargaining power and broader concepts of political power. It notes that the analysis of MNE bargaining power presents a number of puzzles from the perspective of political theory. These puzzles arise, in part, from the fact that the overlap between traditional concepts of MNE bargaining power and broader concepts of political power is only a partial one. Despite these problems, it is suggested that political- theory-based approaches can add realism to our understanding of bargaining power.

Oil and Dependency::The Case of Kazakhstan

Following the collapse of the Soviet Union in 1991, the newly independent oil-rich country of Kazakhstan has become a major recipient of foreign direct investment (FDI). Although international organisations such as the IMF and UNCTAD have claimed that FDI could be considered an engine in the transition from state socialism and as a powerful force for integration of this region into the global economy; this investment also poses significant risks to Kazakhstan. These risks fall into two broad categories: The first category can be broadly described as issues associated with the “resource curse” or the “Dutch Disease”. The term Dutch Disease describes a situation where booming demand in oil exporting countries, due to high oil revenues, leads to shift of an economy’s productive resources from the tradeable sector to the non-tradeable sector. The second category is associated with the over-dependency of oil exporting countries on a relatively small number of large multinational corporations (MNCs). This over-dependency can lead to a situation where licenses and concessions are granted at less favourable conditions than if they were auctioned in an efficient market. Examining the licensing policy of the Kazakhstani Energy and Mineral Resource Ministry, this paper notes that the latter issue of over-dependency has become less of a risk due to deliberate efforts to diversify investment relationships. Notwithstanding this situation there is some evidence that it remains difficult for oil exporting nations such as Kazakhstan to ensure that oil revenues are channelled into sustainable economic development.

Risk in Private Finance Initiative Projects::A Public Sector Perspective

The management of public sector risk is increasingly seen as a priority area of UK government policy. This has been highlighted recently by the Prime Minister Gordon Brown who stated that “the issue of public risk is one of the most challenging areas of policy-making for any government” (Strategic Risk, 2008). In response to these challenges, the UK Prime Minister has appointed a new body - the Risk and Regulation Advisory Council (RRAC) which is tasked with improving the way risk to the public is understood and managed. One area of particular concern with regard to the governance of public sector risks involves projects procured via the Private Finance Initiative (PFI). These projects involve long-term contracts, complex multi-party interactions and thus create various risks to public sector clients. Today, most PFI actors acknowledge the potentially adverse effects of these risks and make an effort to prevent or mitigate undesirable results. As a consequence, issues of risk allocation, risk transfer and risk management have become central to the PFI procurement process. This paper provides an overview of the risk categories and risk types which are relevant to the public sector in PFI projects. It analyses risk as a feature of uncertain future project-related events and examines potential pitfalls which can be associated with PFI risk management on the basis of a case study of a high-profile PFI hospital in Scotland. The paper concludes that, despite the trend towards diminished risk profiles during the operational phase, the public sector continues to be exposed to significant risks when engaging in PFI-based procurement.