Long-Term Oil Price Forecasts: A New Perspective on Oil and the Macroeconomy

We examine how future real GDP growth relates to changes in the forecasted longterm average of discounted real oil prices and to changes in unanticipated fluctuations of real oil prices around the forecasts. Forecasts are conducted using a state-space oil market model, in which global real economic activity and real oil prices share a common stochastic trend. Changes in unanticipated fluctuations and changes in the forecasted longterm average of discounted real oil prices sum to real oil price changes. We find that these two components have distinctly different relationships with future real GDP growth. Positive and negative changes in the unanticipated fluctuations of real oil prices correlate with asymmetric responses of future real GDP growth. In comparison, changes in the forecasted long-term average are smaller in magnitude but are more influential on real GDP. Persistent upward revisions of forecasts in the 2000s had a substantial negative impact on real GDP growth, according to our estimates

Relativistic X-ray Lines from the Inner Accretion Disks Around Black Holes

Relativistic X-ray emission lines from the inner accretion disk around black holes are reviewed. Recent observations with the Chandra X-ray Observatory, X-ray Multi-Mirror Mission-Newton, and Suzaku are revealing these lines to be good probes of strong gravitational effects. A number of important observational and theoretical developments are highlighted, including evidence of black hole spin and effects such as gravitational light bending, the detection of relativistic lines in stellar-mass black holes, and evidence of orbital-timescale line flux variability. In addition, the robustness of the relativistic disk lines against absorption, scattering, and continuum effects is discussed. Finally, prospects for improved measures of black hole spin and understanding the spin history of supermassive black holes in the context of black hole-galaxy co-evolution are presented. The best data and most rigorous results strongly suggest that relativistic X-ray disk lines can drive future explorations of General Relativity and disk physics.Comment: 40 pages, includes color figures, to appear in ARAA, vol 45, in pres

Optimality in DNA repair

Peer reviewedPublisher PD

X-ray Properties of Black-Hole Binaries

We review the properties and behavior X-ray binaries that contain an accreting black hole. The larger majority of such systems are X-ray transients, and many of them were observed in daily pointings with RXTE throughout the course of their outbursts. The complex evolution of these sources is described in terms of common behavior patterns illustrated with comprehensive overview diagrams for six selected systems. Central to this comparison are three X-ray states of accretion, which are reviewed and defined quantitatively. Each state yields phenomena that arise in strong gravitational fields. We sketch a scenario for the potential impact of black hole observations on physics and discuss a current frontier topic: the measurement of black hole spin.Comment: 39 pages, 12 figures, ARAA, vol. 44, in pres

The magnetic nature of disk accretion onto black holes

Although disk accretion onto compact objects - white dwarfs, neutron stars, and black holes - is central to much of high energy astrophysics, the mechanisms which enable this process have remained observationally elusive. Accretion disks must transfer angular momentum for matter to travel radially inward onto the compact object. Internal viscosity from magnetic processes and disk winds can in principle both transfer angular momentum, but hitherto we lacked evidence that either occurs. Here we report that an X-ray-absorbing wind discovered in an observation of the stellar-mass black hole binary GRO J1655-40 must be powered by a magnetic process that can also drive accretion through the disk. Detailed spectral analysis and modeling of the wind shows that it can only be powered by pressure generated by magnetic viscosity internal to the disk or magnetocentrifugal forces. This result demonstrates that disk accretion onto black holes is a fundamentally magnetic process.Comment: 15 pages, 2 color figures, accepted for publication in Nature. Supplemental materials may be obtained by clicking http://www.astro.lsa.umich.edu/~jonmm/nature1655.p

A super massive black hole binary in 3C66B: future observational perspectives

Supermassive black hole binaries (SMBHBs) may exist in the centers of galaxies and active galactic nuclei (AGN) and are expected to be fairly common in the Universe as a consequence of merging processes between galaxies. The existence of SMBHBs can be probed by looking for double nuclei in galaxy centers or, more easily, detecting periodic behavior in the observed radio light curves. In a recent paper, Sudou et al. \cite{sudou2003} announced the first direct observation of an SMBHB. Using VLBI observations they found that the unresolved radio core of the radio galaxy 3C66B shows a well defined elliptical motion with a period of $1.05\pm 0.03$ yrs, implying the presence of a couple of massive black holes in the center of the galaxy. In the present paper we study the astrophysical implications of the existence of such an SMBHB in 3C66B. In particular we focus on the information that can be obtained from detecting a signal periodicity either in the $X$-ray and/or $\gamma$-ray light curves as a consequence of the motion of the black holes. These observations could be used to extract further information on the physical parameters of the SMBHB and partially solve the system parameter degeneracy. The detection of the gravitational wave spectrum emitted by such system may be used to completely determine the physical parameters of the binary system.Comment: 8 pages, 8 figures, in Press on Astronomy & Astrophysic

A new and integrated hydro-economic accounting and analytical framework for water resources: A case study for North China

Water is a critical issue in China for a variety of reasons. China is poor of water resources with 2300 m3 of per capita availability, which is less than of the world average. This is exacerbated by regional differences; e.g. North China's water availability is only about 271 m3 of per capita value, which is only of the world's average. Furthermore, pollution contributes to water scarcity and is a major source for diseases, particularly for the poor. The Ministry of Hydrology [1997. China's Regional Water Bullets. Water Resource and Hydro-power Publishing House, Beijing, China] reports that about 65–80% of rivers in North China no longer support any economic activities. Previous studies have emphasized the amount of water withdrawn but rarely take water quality into consideration. The quality of the return flows usually changes; the water quality being lower than the water flows that entered the production process initially. It is especially important to measure the impacts of wastewater to the hydro-ecosystem. Thus, water consumption should not only account for the amount of water inputs but also the amount of water contaminated in the hydro-ecosystem by the discharged wastewater. In this paper we present a new accounting and analytical approach based on economic input–output modelling combined with a mass balanced hydrological model that links interactions in the economic system with interactions in the hydrological system. We thus follow the tradition of integrated economic–ecologic input–output modelling. Our hydro-economic accounting framework and analysis tool allows tracking water consumption on the input side, water pollution leaving the economic system and water flows passing through the hydrological system thus enabling us to deal with water resources of different qualities. Following this method, the results illustrate that North China requires 96% of its annual available water, including both water inputs for the economy and contaminated water that is ineligible for any uses

Bis(diethyl­enetriamine-κ3 N,N′,N′′)nickel(II) bis­(1,2-dicyanoethene-1,2-dithiolato-κ2 S,S′)nickel(II)

The title compound, [Ni(C4H13N3)2][Ni(C4N2S2)2], has been synthesized by the reaction of Ni(ClO4)2·6H2O, diethyl­enetriamine (deta) and Na2[Ni(mnt)2] [mnt = maleonitrile­dithiol­ate(2-)] in methanol. The structure is composed of a [Ni(deta)2]2+ cation and a [Ni(mnt)2]2− anion. The coordination geometry of the NiII ion in the cation is slightly distorted octa­hedral, defined by six N atoms from two deta ligands, while the NiII ion in the anion is four-coordinated by four S atoms from two mnt ligands in a slightly distorted square-planar geometry. The cations and anions are connected by N—H⋯N hydrogen bonds

Measurements of the Proton-Neutron Correlation in Deuteron Breakup at 260 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Narrow-band imaging pattern classification in oral cavity

Narrow-band imaging is widely used in the diagnostic work-up of oral lesions. Different oral subsites present three epithelial types (1, 2a and 2b), each with a different structure and function. The aim of this study was to analyse and describe the different vascular patterns seen on narrow-band imaging according to oral epithelial type and histology