Climate cost uncertainty, retrofit cost uncertainty, and infrastructure closedown : a framework for analysis

Large and energy-intensive infrastructure investments with long life times have substantial implications for climate policy. This study focuses on options to scale down energy consumption and carbon emissions now and in the future, and on the costs of doing so. Two ways carbon emissions can be reduced post-investment include retrofitting the infrastructure, or closing it down. Generally, the presence of bulky infrastructure investments makes it more costly to reduce emissions later. Moreover, when expected energy and environmental costs are continually rising, inherent biases in the selection processes for infrastructure investments lead to excessive energy intensity in such investments. Thus great care must be taken when choosing the energy intensity of the infrastructure at the time of investment. Simulations indicate that optimally exercising the retrofit option, when it is available, reduces ex ante expected energy consumption relative to the no-option case. Total energy plus retrofit costs can also be substantially reduced, the more so the larger is ex ante cost uncertainty. However, the availability of the retrofit option also leads to a more energy intensive initial infrastructure choice; this offsets some, but usually not all, of the gains from options for subsequent retrofitting.Energy Production and Transportation,Transport Economics Policy&Planning,Climate Change Mitigation and Green House Gases,Climate Change Economics,Environment and Energy Efficiency

A Hybrid Quantum Search Engine: A Fast Quantum Algorithm for Multiple Matches

In this paper we will present a quantum algorithm which works very efficiently in case of multiple matches within the search space and in the case of few matches, the algorithm performs classically. This allows us to propose a hybrid quantum search engine that integrates Grover's algorithm and the proposed algorithm here to have general performance better that any pure classical or quantum search algorithm.Comment: 26 pages, 8 Figure

A Precessing Ring Model for Low-Frequency Quasi-periodic Oscillations

We develop a simple physical model to describe the most common type of low-frequency quasi-periodic oscillations (QPOs) seen in a number of accreting black hole systems, as well as the shape of the relativistically broadened iron emission lines that often appear simultaneously in such sources. The model is based on an inclined ring of hot gas that orbits the black hole along geodesic trajectories. For spinning black holes, this ring will precess around the spin axis of the black hole at the Lense-Thirring (``frame-dragging'') frequency. Using a relativistic ray-tracing code, we calculate X-ray light curves and observed energy spectra as a function of the radius and tilt angle of the ring, the spin magnitude, and the inclination of the black hole. The model predicts higher-amplitude QPOs for systems with high inclinations, as seen in a growing number of black hole binary systems. We find that the Rossi X-ray Timing Explorer observations of low-frequency QPOs in GRS 1915+105 are consistent with a ring of radius R ~ 10M orbiting a black hole with spin a/M ~0.5 and inclination angle of i ~ 70 deg. Finally, we describe how future X-ray missions may be able to use simultaneous timing and spectroscopic observations to measure the black hole spin and probe the inner-most regions of the accretion disk.Comment: Accepted to ApJ, 22 pages, 7 figure

Whose outcomes are they anyway? Report of the pilot evaluation of a joint service\ud

Health and social care partnership working is often predicated on the notion that it improves outcomes for service users. Yet there is a lack of evidence linking partnerships to changes in outcomes. Against this background, the Health Services Management Centre at the University of Birmingham designed the Partnership Outcomes Evaluation Toolkit (POET) specifically to evaluate health and social care partnerships in terms of service user outcomes. This paper reports on the field testing of POET with Sandwell Integrated Support Service. This research provided a number of interesting insights into this service, and indicated some dissonance between staff and service user and carer expectations

Infrastructure investments under uncertainty with the possibility of retrofit : theory and simulations

Investments in large, long-lived, energy-intensive infrastructure investments using fossil fuels increase longer-term energy use and greenhouse gas emissions, unless the plant is shut down early or undergoes costly retrofit later. These investments will depend on expectations of retrofit costs and future energy costs, including energy cost increases from tighter controls on carbon emissions. Simulation analysis shows that the retrofit option can significantly reduce anticipated future energy consumption as of the time of initial investment, and total future energy plus retrofit costs. The more uncertain are the costs, the greater the value of this option. However, the future retrofit option also induces more energy-intensive infrastructure choices, partly offsetting the direct effect of having the option on anticipated energy use. Efficient, forward-looking infrastructure investments have high potential for reducing long-term energy consumption. Particularly if energy prices are expected to rise, however, the potential for reduced energy consumption will be eroded if expectations of energy prices do not include environmental costs or future retrofit possibilities and technologies are not adequately developed.Energy Production and Transportation,Climate Change Economics,Climate Change Mitigation and Green House Gases,Environment and Energy Efficiency,Energy and Environment

A detailed study of the 5 Hz quasi-periodic oscillations in the bright X-ray transient and black-hole candidate GRS 1739-278

We present a detailed study of the 5 Hz quasi-periodic oscillation (QPO) recently discovered in the bright X-ray transient and black-hole candidate GRS 1739-278 (Borozdin & Trudolyubov 2000) during a Rossi X-ray Timing Explorer observation taken on 1996 March 31. In total 6.6 ksec of on-source data were obtained, divided in two data sets of 3.4 and 3.2 ksec which were separated by 2.6 ksec. The 5 Hz QPO was only present during the second data set. The QPO increased in strength from below 2% rms amplitude for photon energies below 4 keV to ~5% rms amplitude for energies above 10 keV. The soft QPO photons (below 5 keV) lagged the hard ones (above 10 keV) by almost 1.5 radian. Besides the QPO fundamental, its first overtone was detected. The strength of the overtone increased with photon energy (from <2% rms below 5 keV to ~8% rms above 10 keV). Although the limited statistics did not allow for an accurate determination of the lags of the first overtone, indications are that also for this QPO the soft photons lagged the hard ones. When the 5 Hz QPO was not detected (i.e., during the first part of the observation), a broad noise component was found for photon energies below 10 keV but it became almost a true QPO (with a Q value of ~1.9) above that energy, with a frequency of ~3 Hz. Its hard photons preceded the soft ones in a way reminiscent of the 5 Hz QPO, strongly suggesting that both features are physically related. We discuss our finding in the frame work of low-frequency QPOs and their properties in BHCs.Comment: Accepted for publication in MNRAS, 2 August 200

Chandra grating spectroscopy of the Be/X-ray binary 1A 0535+262

We present Chandra HETGS spectroscopy of the Be/X-ray binary 1A 0535+262 obtained during the 2009/2010 giant outburst. These are the first CCD grating spectra of this type of system during a giant outburst. Our spectra reveal a number of lines including a narrow Fe K_alpha emission line with a FWHM of ~ 5000 km s^-1. For the first time, we detect the presence of a highly ionized outflow in a Be/X-ray binary. Assuming that the line is He-like Fe XXV, fits with a simple Gaussian imply an outflow velocity of ~ 1500 km s^-1. However, self-consistent photoionization modeling with XSTAR suggests that Fe XXIII-XXIV must also contribute. In this case, an outflow velocity of ~ 3000 km s^-1 is implied. These results are discussed in the context of the accretion flow in Be-star, neutron star, and black hole X-ray binaries.Comment: 7 pages, 4 figures, formatted using emulateapj.cls. Accepted for publication in Ap

Essays in Visual History: Making Use of the International Mission Photography Archive

An extraordinary resource for comparative research in the humanities can be found in the historical images that comprise the International Mission Photography Archive (IMPA). The 62,000 photographs presently in the database represent cultures across Africa, India, China, Korea, Japan, Oceania, the Caribbean, and Papua New Guinea. The requested NEH Level 1 start-up grant will support a workshop devoted to the design of a series of visual essays authored by accomplished scholars who will use images from IMPA to explore topics in their areas of expertise. Called Essays in Visual History, the series will be hosted by the USC Digital Library and featured on the website of the Center for Religion and Civic Culture (CRCC). The workshop will explore relationships with other publication initiatives at USC, specifically those under development by the Center for Transformative Scholarship and The Alliance for Networking Visual Culture, which offer opportunities to maximize the visibility of the of the proposed series