Fundamental and financial influences on the co-movement of oil and gas prices

As speculative flows into commodity futures are expected to link commodity prices more strongly to equity indices, we investigate whether this process also creates increased correlations amongst the commodities themselves. Considering U.S. oil and gas futures, we investigate whether common factors, derived from a large international data set of real and nominal macroeconomic variables by means of the large approximate factor models methodology, are able to explain both returns and whether, beyond these fundamental common factors, the residuals remain correlated. We further investigate a possible explanation for this residual correlation by using some proxies for trading intensity derived from CFTC publicly available data, showing most notably that the proxy for speculation in the oil market increases the oil-gas correlation. We thus identify the central role of financial activities in shaping the link between oil and gas returns

Detectability of Microwave Background Polarization

[NOTE: Previous versions of this paper (both on astro-ph and published in Phys. Rev. D) contain results that are in error. The power spectra C_l were normalized incorrectly by a factor of 2 pi. All observing times in detector-years in those versions are too large by a factor of 2 pi. The main place these numbers appear is on the vertical axes of Figures 4 and 5. Note that because all calculations were based on the same power spectra, all conclusions pertaining to comparisons of different techniques remain unchanged. This error has been corrected in the present version of the paper. An erratum is being sent to Phys. Rev. D. I apologize for the error.] Using a Fisher-matrix formalism, we calculate the required sensitivities and observing times for an experiment to measure the amplitudes of both E and B components as a function of sky coverage, taking full account of the fact that the two components cannot be perfectly separated in an incomplete sky map. We also present a simple approximation scheme that accounts for mixing of E and B components in computing predicted errors in the E-component power spectrum amplitude. In an experiment with small sky coverage, mixing of the two components increases the difficulty of detecting the subdominant B component by a factor of two or more in observing time; however, for larger survey sizes the effect of mixing is less pronounced. Surprisingly, mixing of E and B components can enhance the detectability of the E component by increasing the effective number of independent modes that probe this componentComment: Previous versions of this paper contained results that were in error. The present version on astro-ph has been corrected, and an erratum is being submitted. See abstract for detail

Cluster Analysis and Topoclimate Modeling to Examine Bristlecone Pine Tree-ring Growth Signals in the Great Basin, USA

Tree rings have long been used to make inferences about the environmental factors that influence tree growth. Great Basin bristlecone pine is a long-lived species and valuable dendroclimatic resource, but often with mixed growth signals; in many cases, not all trees at one location are limited by the same environmental variable. Past work has identified an elevational threshold below the upper treeline above which trees are limited by temperature, and below which trees tend to be moisture limited. This study identifies a similar threshold in terms of temperature instead of elevation through fine-scale topoclimatic modeling, which uses a suite of topographic and temperature-sensor data to predict temperatures across landscapes. We sampled trees near the upper limit of growth at four high-elevation locations in the Great Basin region, USA, and used cluster analysis to find dual-signal patterns in radial growth. We observed dual-signal patterns in ring widths at two of those sites, with the signals mimicking temperature and precipitation patterns. Trees in temperature-sensitive clusters grew in colder areas, while moisture-sensitive cluster trees grew in warmer areas. We found thresholds between temperatureand moisture-sensitivity ranging from 7.4 °C to 8°C growing season mean temperature. Our findings allow for a better physiological understanding of bristlecone pine growth, and seek to improve the accuracy of climate reconstructions

VLTI/MIDI 10 micron interferometry of the forming massive star W33A

We report on resolved interferometric observations with VLTI/MIDI of the massive young stellar object (MYSO) W33A. The MIDI observations deliver spectrally dispersed visibilities with values between 0.03 and 0.06, for a baseline of 45m over the wavelength range 8-13 micron. The visibilities indicate that W33A has a FWHM size of approximately 120AU (0.030'') at 8 micron which increases to 240AU at 13 micron, scales previously unexplored among MYSOs. This observed trend is consistent with the temperature falling off with distance. 1D dust radiative transfer models are simultaneously fit to the visibility spectrum, the strong silicate feature and the shape of the mid infrared spectral energy distribution (SED). For any powerlaw density distribution, we find that the sizes (as implied by the visibilities) and the stellar luminosity are incompatible. A reduction to a third of W33A's previously adopted luminosity is required to match the visibilities; such a reduction is consistent with new high resolution 70 micron data from Spitzer's MIPSGAL survey. We obtain best fits for models with shallow dust density distributions of r^(-0.5) and r^(-1.0) and for increased optical depth in the silicate feature produced by decreasing the ISM ratio of graphite to silicates and using optical grain properties by Ossenkopf et al. (1992).Comment: 4 pages, 4 figures. Accepted for ApJ letter

The Virtual Astronomical Observatory: Re-engineering access to astronomical data

The US Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the US coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within the US National Virtual Observatory, and summarizes its main accomplishments. These accomplishments include the development of both scripting toolkits that allow scientists to incorporate VO data directly into their reduction and analysis environments and high-level science applications for data discovery, integration, analysis, and catalog cross-comparison. Working with the international community, and based on the experience from the software development, the VAO was a major contributor to international standards within the International Virtual Observatory Alliance. The VAO also demonstrated how an operational virtual observatory could be deployed, providing a robust operational environment in which VO services worldwide were routinely checked for aliveness and compliance with international standards. Finally, the VAO engaged in community outreach, developing a comprehensive web site with on-line tutorials, announcements, links to both US and internationally developed tools and services, and exhibits and hands-on training at annual meetings of the American Astronomical Society and through summer schools and community days. All digital products of the VAO Project, including software, documentation, and tutorials, are stored in a repository for community access. The enduring legacy of the VAO is an increasing expectation that new telescopes and facilities incorporate VO capabilities during the design of their data management systems

The variation in capacity remunerations requirements in European electricity markets

This paper provides the first EU wide analysis of the variation in Capacity Remuneration Requirements throughout Europe which aim to resolve the “missing money” problems in various member states. The findings of this analysis point to an asymmetric investment case for gas-fired peaking power plants throughout the EU. Under the assumptions of the European Commission Reference Scenario, pan-European power optimisation and investment models are specified for 2030. The results show that future investment in gas generators will depend on the availability of capacity payments. Capacity remuneration mechanisms can provide this “missing money”, but we show that capacity remuneration requirements vary considerably across countries. We consider and model the impacts of country specific climate policy targets, sovereign risk, capital allowances, corporate taxes and future gas network tariffs on investor returns and therefore remuneration requirements. In the context of harmonised energy trading, this raises questions of how generation adequacy should be achieved, particularly in the context of higher penetrations of renewables

Cosmic structure formation in Hybrid Inflation models

A wide class of inflationary models, known as Hybrid Inflation models, may produce topological defects during a phase transition at the end of the inflationary epoch. We point out that, if the energy scale of these defects is close to that of Grand Unification, then their effect on cosmic structure formation and the generation of microwave background anisotropies cannot be ignored. Therefore, it is possible for structure to be seeded by a combination of the adiabatic perturbations produced during inflation and active isocurvature perturbations produced by defects. Since the two mechanisms are uncorrelated the power spectra can be computed by a weighted average of the individual contributions. We investigate the possible observational consequences of this with reference to general Hybrid Inflation models and also a specific model based on Supergravity. These mixed perturbation scenarios have some novel observational consequences and these are discussed qualitatively.Comment: 22 Page

Three flavor neutrino oscillation analysis of the Superkamiokande atmospheric neutrino data

Superkamiokande atmospheric neutrino data for 535 days are analyzed in the framework of three flavor oscillations with mass hierarchy. It is shown that the best fit point is very close to the pure maximal $\nu_\mu\leftrightarrow\nu_\tau$ case and $\Delta m^2 \simeq 7\times10^{-3}$ eV$^2$. The allowed region at 90 %CL is given and the implications to the long baseline experiments are briefly discussed.Comment: 8 pages + 1 Table + 28 PostScript figures updated using 535 day dat

Foreground removal from WMAP 7yr polarization maps using an MLP neural network

One of the fundamental problems in extracting the cosmic microwave background signal (CMB) from millimeter/submillimeter observations is the pollution by emission from the Milky Way: synchrotron, free-free, and thermal dust emission. To extract the fundamental cosmological parameters from CMB signal, it is mandatory to minimize this pollution since it will create systematic errors in the CMB power spectra. In previous investigations, it has been demonstrated that the neural network method provide high quality CMB maps from temperature data. Here the analysis is extended to polarization maps. As a concrete example, the WMAP 7-year polarization data, the most reliable determination of the polarization properties of the CMB, has been analysed. The analysis has adopted the frequency maps, noise models, window functions and the foreground models as provided by the WMAP Team, and no auxiliary data is included. Within this framework it is demonstrated that the network can extract the CMB polarization signal with no sign of pollution by the polarized foregrounds. The errors in the derived polarization power spectra are improved compared to the errors derived by the WMAP Team.Comment: Accepted for publication in Astrophysics & Space Scienc

Differential Impact of Calcium and Vitamin D on Body Composition Changes in Post-Menopausal Women Following a Restricted Energy Diet and Exercise Program

Vitamin D and calcium supplementation have been posited to improve body composition and different formulations of calcium may impact bioavailability. However, data are lacking regarding the combinatorial effects of exercise, diet, and calcium and/or vitamin D supplementation on body composition changes in post-menopausal women. Herein, 128 post-menopausal women (51.3 ± 4.5 years, 36.4 ± 5.7 kg/m2, 46.2 ± 4.5% fat) were assigned to diet and supplement groups while participating in a supervised circuit-style resistance-training program (3 d/week) over a 14-week period. Diet groups included: (1) normal diet (CTL), (2) a low-calorie, higher protein diet (LCHP; 1600 kcal/day, 15% carbohydrates, 55% protein, 30% fat), and (3) a low-calorie, higher carbohydrate diet (LCHC; 1600 kcal/day, 55% carbohydrates, 15% protein, 30% fat). Supplement groups consisted of: (1) maltodextrin (PLA), (2) 800 mg/day of calcium carbonate (Ca), and (3) 800 mg/day of calcium citrate and malate and 400 IU/day of vitamin D (Ca+D). Fasting blood samples, body composition, resting energy expenditure, aerobic capacity, muscular strength and endurance measures were assessed. Data were analyzed by mixed factorial ANOVA with repeated measures and presented as mean change from baseline [95% CI]. Exercise training promoted significant improvements in strength, peak aerobic capacity, and blood lipids. Dieting resulted in greater losses of body mass (CTL −0.4 ± 2.4; LCHC −5.1 ± 4.2; LCHP −3.8 ± 4.2 kg) and fat mass (CTL −1.4 ± 1.8; LCHC −3.7 ± 3.7; LCHP −3.4 ± 3.4 kg). When compared to LCHC-PLA, the LCHC + Ca combination led to greater losses in body mass (PLA −4.1 [−6.1, −2.1], Ca −6.4 [−8.1, −4.7], Ca+D −4.4 [−6.4, −2.5] kg). In comparison to LCHC-Ca, the LCHC-Ca+D led to an improved maintenance of fat-free mass (PLA −0.3 [−1.4, 0.7], Ca −1.4 [−2.3, −0.5], Ca+D 0.4 [−0.6, 1.5] kg) and a greater loss of body fat (PLA −2.3 [−3.4, −1.1], Ca −1.3 [−2.3, −0.3], Ca+D −3.6 [−4.8, −2.5]%). Alternatively, no significant differences in weight loss or body composition resulted when adding Ca or Ca+D to the LCHP regimen in comparison to when PLA was added to the LCHP diet. When combined with an energy-restricted, higher carbohydrate diet, adding 800 mg of Ca carbonate stimulated greater body mass loss compared to when a PLA was added. Alternatively, adding Ca+D to the LCHC diet promoted greater% fat changes and attenuation of fat-free mass loss. Our results expand upon current literature regarding the impact of calcium supplementation with dieting and regular exercise. This data highlights that different forms of calcium in combination with an energy restricted, higher carbohydrate diet may trigger changes in body mass or body composition while no impact of calcium supplementation was observed when participants followed an energy restricted, higher protein diet