Oscillating Neutrinos from the Galactic Center

It has recently been demonstrated that the $\gamma$-ray emission spectrum of the EGRET-identified, central Galactic source 2EG J1746-2852 can be well fitted by positing that these photons are generated by the decay of $\pi^0$'s produced in p-p scattering at or near an energizing shock. Such scattering also produces charged pions which decay leptonically.The ratio of $\gamma$-rays to neutrinos generated by the central Galactic source may be accurately determined and a well-defined and potentially-measurable high energy neutrino flux at Earth is unavoidable. An opportunity, therefore, to detect neutrino oscillations over an unprecedented scale is offered by this source. In this paper we assess the prospects for such an observation with the generation of neutrino \v{C}erenkov telescopes now in the planning stage. We determine that the next generation of detectors may find an oscillation signature in the Galactic Center (GC) signal.Comment: 45 pages, LaTeX, uses ApJ style, some minor revisions, this final version to be published in ApJ

Measuring the Black Hole Spin in Sgr A*

The polarized mm/sub-mm radiation from Sgr A* is apparently produced by a Keplerian structure whose peak emission occurs within several Schwarzschild radii (r_S=2GM/c^2) of the black hole. The Chandra X-ray counterpart, if confirmed, is presumably the self-Comptonized component from this region. In this paper, we suggest that sub-mm timing observations could yield a signal corresponding to the period P_0 of the marginally stable orbit, and therefore point directly to the black hole's spin a. Sgr A*'s mass is now known to be (2.6\pm 0.2)\times 10^6 M_\odot (an unusually accurate value for supermassive black hole candidates), for which 2.7 min<P_0<36 min, depending on the value of a and whether the Keplerian flow is prograde or retrograde. A Schwarzschild black hole (a=0) should have P_0 ~ 20 min. The identification of the orbital frequency with the innermost stable circular orbit is made feasible by the transition from optically thick to thin emission at sub-mm wavelengths. With stratification in the emitter, the peak of the sub-mm bump in Sgr A*'s spectrum is thus produced at the smallest radius. We caution, however, that theoretical uncertainties in the structure of the emission region may still produce some ambiguity in the timing signal. Given that Sgr A*'s flux at $\nu\sim 1$ mm is several Jy, these periods should lie within the temporal-resolving capability of sub-mm telescopes using bolometric detectors. A determination of P_0 should provide not only a value of a, but it should also define the angular momentum vector of the orbiting gas in relation to the black hole's spin axis. In addition, since the X-ray flux detected by Chandra appears to be the self-Comptonized mm to sub-mm component, these temporal fluctuations may also be evident in the X-ray signal.Comment: 15 pages, 1 figures. Accepted for publication in ApJ Letter

SAT based Enforcement of Domotic Effects in Smart Environments

The emergence of economically viable and efficient sensor technology provided impetus to the development of smart devices (or appliances). Modern smart environments are equipped with a multitude of smart devices and sensors, aimed at delivering intelligent services to the users of smart environments. The presence of these diverse smart devices has raised a major problem of managing environments. A rising solution to the problem is the modeling of user goals and intentions, and then interacting with the environments using user defined goals. `Domotic Effects' is a user goal modeling framework, which provides Ambient Intelligence (AmI) designers and integrators with an abstract layer that enables the definition of generic goals in a smart environment, in a declarative way, which can be used to design and develop intelligent applications. The high-level nature of domotic effects also allows the residents to program their personal space as they see fit: they can define different achievement criteria for a particular generic goal, e.g., by defining a combination of devices having some particular states, by using domain-specific custom operators. This paper describes an approach for the automatic enforcement of domotic effects in case of the Boolean application domain, suitable for intelligent monitoring and control in domotic environments. Effect enforcement is the ability to determine device configurations that can achieve a set of generic goals (domotic effects). The paper also presents an architecture to implement the enforcement of Boolean domotic effects, and results obtained from carried out experiments prove the feasibility of the proposed approach and highlight the responsiveness of the implemented effect enforcement architectur

Proper Size of the Visible Universe in FRW Metrics with Constant Spacetime Curvature

In this paper, we continue to examine the fundamental basis for the Friedmann-Robertson-Walker (FRW) metric and its application to cosmology, specifically addressing the question: What is the proper size of the visible universe? There are several ways of answering the question of size, though often with an incomplete understanding of how far light has actually traveled in reaching us today from the most remote sources. The difficulty usually arises from an inconsistent use of the coordinates, or an over-interpretation of the physical meaning of quantities such as the so-called proper distance R(t)=a(t)r, written in terms of the (unchanging) co-moving radius r and the universal expansion factor a(t). In this paper, we use the five non-trivial FRW metrics with constant spacetime curvature (i.e., the static FRW metrics, but excluding Minkowski) to prove that in static FRW spacetimes in which expansion began from an initial signularity, the visible universe today has a proper size equal to R_h(t_0/2), i.e., the gravitational horizon at half its current age. The exceptions are de Sitter and Lanczos, whose contents had pre-existing positions away from the origin. In so doing, we confirm earlier results showing the same phenomenon in a broad range of cosmologies, including LCDM, based on the numerical integration of null geodesic equations through an FRW metric.Comment: Accepted for publication in Classical and Quantum Gravit

Benchmarking Technical and Cost Factors in Forest Felling and Processing Operations in Different Global Regions during the Period 2013-2014

In a global bioeconomy, benchmarking costs is essential in the evaluation of current forest harvesting systems and addressing decisions on the most efficient supply chains for available forest resources. Benchmarking cost rates in forestry is challenging, due to a lack of harmonized terminology and difficulties in collecting information on comparable forest technologies. This study provides a first-time series of cost factors to be used when modeling and evaluating the cost competitiveness of forest felling and processing operations on a global scale. It is based on an expert survey using a standardized method of data collection. This benchmarking identifies and updates the knowledge of technical and socio-economic factors capable of influencing the cost rates of forest felling and processing operations across different regions. This study is expected to act as a reference for larger investigations, and for regular updates, with the aim to provide current data that can be used by forest practitioners and decision makers for improving their cost efficiency and for designing future supply systems more effectively

Accretion Disk Evolution With Wind Infall I. General Solution and Application to Sgr A*

The evolution of an accretion disk can be influenced significantly by the deposition of mass and angular momentum by an infalling Bondi-Hoyle wind. Such a mass influx impacts the long-term behavior of the disk by providing additional sources of viscosity and heating. In this paper, we derive and solve the disk equations when these effects are taken into account. We present a survey of models with various wind configurations and demonstrate that the disk spectrum may then differ substantially from that of a standard alpha-disk. In particular, it is likely that a wind-fed disk has a significant infrared bump due to the deposition of energy in its outer region. We apply some of the results of our calculations to the Galactic Center black hole candidate Sgr A* and show that if a fossil disk is present in this source, it must have a very low viscosity parameter (alpha<10^-4) and the Bondi-Hoyle wind must be accreting with a very high specific angular momentum to prevent it from circularizing in the inner disk region where its impact would be most noticeable.Comment: accepted for The Astrophysical Journal, AAS LaTex, 20 pages, also available at http://www.astro.umd.edu/~hfalcke/publications.html#wintercep

DynNav: Toward Open and Interoperable Dynamic Navigation Services

So far, navigation devices, including navigation apps for smartphones, have been proprietary and closed. A new scenario is emerging with the Open Mobile Alliance Dynamic Navigation Enabler, which lets developers create novel navigation services characterized by openness and interoperability across different information providers

2D continuous spectrum of shear Alfven waves in the presence of a magnetic island

The radial structure of the continuous spectrum of shear Alfven modes is calculated in the presence of a magnetic island in tokamak plasmas. Modes with the same helicity of the magnetic island are considered in a slab model approximation. In this framework, with an appropriate rotation of the coordinates the problem reduces to 2 dimensions. Geometrical effects due to the shape of the flux surface's cross section are retained to all orders. On the other hand, we keep only curvature effects responsible of the beta induced gap in the low-frequency part of the continuous spectrum. New continuum accumulation points are found at the O-point of the magnetic island. The beta-induced Alfven Eigenmodes (BAE) continuum accumulation point is found to be positioned at the separatrix flux surface. The most remarkable result is the nonlinear modification of the BAE continuum accumulation point frequency

Anomalous scaling due to correlations: Limit theorems and self-similar processes

We derive theorems which outline explicit mechanisms by which anomalous scaling for the probability density function of the sum of many correlated random variables asymptotically prevails. The results characterize general anomalous scaling forms, justify their universal character, and specify universality domains in the spaces of joint probability density functions of the summand variables. These density functions are assumed to be invariant under arbitrary permutations of their arguments. Examples from the theory of critical phenomena are discussed. The novel notion of stability implied by the limit theorems also allows us to define sequences of random variables whose sum satisfies anomalous scaling for any finite number of summands. If regarded as developing in time, the stochastic processes described by these variables are non-Markovian generalizations of Gaussian processes with uncorrelated increments, and provide, e.g., explicit realizations of a recently proposed model of index evolution in finance.Comment: Through text revision. 15 pages, 3 figure

Matching matrix elements and shower evolution for top-quark production in hadronic collisions

We study the matching of multijet matrix elements and shower evolution in the case of top production in hadronic collisions at the Tevatron and at the LHC. We present the results of the matching algorithm implemented in the ALPGEN Monte Carlo generator, and compare them with results obtained at the parton level, and with the predictions of the MC@NLO approach. We highlight the consistency of the matching algorithm when applied to these final states, and the excellent agreement obtained with MC@NLO for most inclusive quantities. We nevertheless identify also a remarkable difference in the rapidity spectrum of the leading jet accompanying the top quark pair, and comment on the likely origin of this discrepancy.Comment: 22 pages, 13 figures, 5 tables. JHEP styl