Science.gov

Sample records for 100-year time horizon

  1. Opening the 100-Year Window for Time-Domain Astronomy

    NASA Astrophysics Data System (ADS)

    Grindlay, Jonathan; Tang, Sumin; Los, Edward; Servillat, Mathieu

    2012-04-01

    The large-scale surveys such as PTF, CRTS and Pan-STARRS-1 that have emerged within the past 5 years or so employ digital databases and modern analysis tools to accentuate research into Time Domain Astronomy (TDA). Preparations are underway for LSST which, in another 6 years, will usher in the second decade of modern TDA. By that time the Digital Access to a Sky Century @ Harvard (DASCH) project will have made available to the community the full sky Historical TDA database and digitized images for a century (1890-1990) of coverage. We describe the current DASCH development and some initial results, and outline plans for the ``production scanning'' phase and data distribution which is to begin in 2012. That will open a 100-year window into temporal astrophysics, revealing rare transients and (especially) astrophysical phenomena that vary on time-scales of a decade. It will also provide context and archival comparisons for the deeper modern surveys.

  2. Spectroscopic Binaries: Towards the 100-Year Time Domain

    NASA Astrophysics Data System (ADS)

    Griffin, R. F.

    2012-04-01

    Good measurements of visual binary stars (position angle and angular separation) have been made for nearly 200 years. Radial-velocity observers have exhibited less patience; when the orbital periods of late-type stars in the catalogue published in 1978 are sorted into bins half a logarithmic unit wide, the modal bin is the one with periods between 3 and 10 days. The same treatment of the writer's orbits shows the modal bin to be the one between 1000 and 3000 days. Of course the spectroscopists cannot quickly catch up the 200 years that the visual observers have been going, but many spectroscopic orbits with periods of decades, and a few of the order of a century, have been published. Technical developments have also been made in `visual' orbit determination, and orbits with periods of only a few days have been determined for certain `visual' binaries. In principle, therefore, the time domains of visual and spectroscopic binaries now largely overlap. Overlap is essential, as it is only by combining both techniques that orbits can be determined in three dimensions, as is necessary for the important objective of determining stellar masses accurately. Nevertheless the actual overlap-objects with accurate measurements by both techniques-remains disappointingly small. There have, however, been unforeseen benefits from the observation of spectroscopic binaries that have unconventionally long orbital periods, not a few of which have proved to be interesting and significant objects in their own right. It has also been shown that binary membership is more common than was once thought (orbits have even been determined for some of the IAU standard radial-velocity stars!); a recent study of the radial velocities of K giants that had been monitored for 45 years found a binary incidence of 30%, whereas a figure of 13.7% was given as recently as 2005 for a similar group.

  3. The life and times of the LED - a 100-year history

    NASA Astrophysics Data System (ADS)

    Zheludev, Nikolay

    2007-04-01

    Many people believe that the LED was discovered by US researchers working in the 1960s. In fact, Henry Round at Marconi Labs noted the emission of light from a semiconductor diode 100 years ago and, independently, a forgotten Russian genius - Oleg Losev - discovered the LED.

  4. Tuskegee: 100 Years Later.

    ERIC Educational Resources Information Center

    Higgins, Renelda

    1981-01-01

    Reviews the history and accomplishments of Tuskegee Institute over the past 100 years. Highlights the role played by Booker T. Washington, and W. E. B. DuBois; discusses the career of the school's retiring president, Luther Foster. Provides information on the new president, Dr. Benjamin Payton, and discusses future directions for the college. (APM)

  5. Time Horizon and Social Scale in Communication

    NASA Astrophysics Data System (ADS)

    Krantz, D. H.

    2010-12-01

    In 2009 our center (CRED) published a first version of The Psychology of Climate Change Communication. In it, we attempted to summarize facts and concepts from psychological research that could help guide communication. While this work focused on climate change, most of the ideas are at least partly applicable for communication about a variety of natural hazards. Of the many examples in this guide, I mention three. Single-action bias is the human tendency to stop considering further actions that might be needed to deal with a given hazard, once a single action has been taken. Another example is the importance of group affiliation in motivating voluntary contributions to joint action. A third concerns the finding that group participation enhances understanding of probabilistic concepts and promotes action in the face of uncertainty. One current research direction, which goes beyond those included in the above publication, focuses on how time horizons arise in the thinking of individuals and groups, and how these time horizons might influence hazard preparedness. On the one hand, individuals sometimes appear impatient, organizations look for immediate results, and officials fail to look beyond the next election cycle. Yet under some laboratory conditions and in some subcultures, a longer time horizon is adopted. We are interested in how time horizon is influenced by group identity and by the very architecture of planning and decision making. Institutional changes, involving long-term contractual relationships among communities, developers, insurers, and governments, could greatly increase resilience in the face of natural hazards. Communication about hazards, in the context of such long-term contractual relationships might look very different from communication that is first initiated by immediate threat. Another new direction concerns the social scale of institutions and of communication about hazards. Traditionally, insurance contracts share risk among a large

  6. [100 years' of clinical electrocardiography].

    PubMed

    Bergovec, Mijo

    2003-01-01

    In 1903 Willem Einthoven published in Pflügers Arch his classic article on the investigation of human electrocardiogram by his string galvanometer. Many historians of medicine, Einthoven also marked that publication as the beginning of clinical electrocardiography. Many investigators like Galvani, Manteucci, Kölliker, Müller, Lipmann, Waller, Ader, Einthoven, Lewis, Wilson and others participated in creation and development of electrocardiogram. From that time electrocardiogram quickly became, and has remained the most essential diagnostic laboratory tool in investigation of heart diseases. The aim of this article is to remind us of the beginning of this part of cardiology 100 years ago. PMID:15209030

  7. NETL: The First 100 Years

    SciTech Connect

    2015-07-21

    The National Energy Technology Laboratory celebrates 100 years of innovative energy technology development. NETL has been a leader in energy technology development. This video takes a look back at the many accomplishments over the past 100 years. These advances benefit the American people, enhance our nation's energy security and protect our natural resources.

  8. Horizons versus singularities in spherically symmetric space-times

    SciTech Connect

    Bronnikov, K. A.; Elizalde, E.; Odintsov, S. D.; Zaslavskii, O. B.

    2008-09-15

    We discuss different kinds of Killing horizons possible in static, spherically symmetric configurations and recently classified as 'usual', 'naked', and 'truly naked' ones depending on the near-horizon behavior of transverse tidal forces acting on an extended body. We obtain the necessary conditions for the metric to be extensible beyond a horizon in terms of an arbitrary radial coordinate and show that all truly naked horizons, as well as many of those previously characterized as naked and even usual ones, do not admit an extension and therefore must be considered as singularities. Some examples are given, showing which kinds of matter are able to create specific space-times with different kinds of horizons, including truly naked ones. Among them are fluids with negative pressure and scalar fields with a particular behavior of the potential. We also discuss horizons and singularities in Kantowski-Sachs spherically symmetric cosmologies and present horizon regularity conditions in terms of an arbitrary time coordinate and proper (synchronous) time. It turns out that horizons of orders 2 and higher occur in infinite proper times in the past or future, but one-way communication with regions beyond such horizons is still possible.

  9. The WSMR Timing System: Toward New Horizons

    NASA Technical Reports Server (NTRS)

    Gilbert, William A.; Stimets, Bob

    1996-01-01

    In 1991, White Sands Missile Range (WSMR) initiated a modernization program for its range timing system. The main focus of this modernization program was to develop a system that was highly accurate, easy to maintain, and portable. The logical decision at the time was to develop a system based solely on Global Positioning System (GPS) technology. Since that time, wsmr has changed its philosophy on how GPS would be utilized for the timing system. This paper will describe WSMR's initial modernization plans for its range timing system and how certain events have led to a modification of these plans.

  10. Time Horizons, Discounting, and Intertemporal Choice

    ERIC Educational Resources Information Center

    Streich, Philip; Levy, Jack S.

    2007-01-01

    Although many decisions involve a stream of payoffs over time, political scientists have given little attention to how actors make the required tradeoffs between present and future payoffs, other than applying the standard exponential discounting model from economics. After summarizing the basic discounting model, we identify some of its leading…

  11. 100 years of Lewy pathology.

    PubMed

    Goedert, Michel; Spillantini, Maria Grazia; Del Tredici, Kelly; Braak, Heiko

    2013-01-01

    In 1817, James Parkinson described the symptoms of the shaking palsy, a disease that was subsequently defined in greater detail, and named after Parkinson, by Jean-Martin Charcot. Parkinson expected that the publication of his monograph would lead to a rapid elucidation of the anatomical substrate of the shaking palsy; in the event, this process took almost a century. In 1912, Fritz Heinrich Lewy identified the protein aggregates that define Parkinson disease (PD) in some brain regions outside the substantia nigra. In 1919, Konstantin Nikolaevich Tretiakoff found similar aggregates in the substantia nigra and named them after Lewy. In the 1990s, α-synuclein was identified as the main constituent of the Lewy pathology, and its aggregation was shown to be central to PD, dementia with Lewy bodies, and multiple system atrophy. In 2003, a staging scheme for idiopathic PD was introduced, according to which α-synuclein pathology originates in the dorsal motor nucleus of the vagal nerve and progresses from there to other brain regions, including the substantia nigra. In this article, we review the relevance of Lewy's discovery 100 years ago for the current understanding of PD and related disorders. PMID:23183883

  12. The AAS: Its Next 100 Years

    NASA Astrophysics Data System (ADS)

    Wolff, S.

    1999-05-01

    The AAS: Its Next Hundred Years "We are probably nearing the limit of all we can know about astronomy."-- Simon Newcomb, 1888. The best way to celebrate the centennial of the AAS is to look forward, not backward, and to begin planning for the next 100 years. However, predicting the future is even more difficult than it was in Newcomb's time. We live in an era characterized by an unprecedented rate of change in the kinds of scientific questions we ask, the tools we use to answer them, and the way we communicate our results. This talk will highlight some of the issues that we will face as a community during the next 10--but not the next 100!--years and suggests that the AAS has a fundamental role to play in shaping the community response to these issues.

  13. 100 years of Philips Research

    NASA Astrophysics Data System (ADS)

    van Delft, Dirk

    2014-03-01

    On Thursday 23 October 1913, a Dutch newspaper published the following advertisement: Hiring: A capable young scientist with a doctorate in physics. Must be a good experimenter. Letters containing information on age, life history and references may be submitted to Philips in Eindhoven. Two days later, a candidate applied: Gilles Holst. At that time, Holst was working in Leiden as an assistant to Heike Kamerlingh Onnes, a recent Nobel Prize winner.

  14. [Dermatitis artefacta 100 years ago].

    PubMed

    Heras-Mendaza, F

    2009-10-01

    In 1909, the Spanish dermatologist Juan de Azúa published a study of the main features of skin lesions in dermatitis artefacta. In the article, he paid particular attention to the psychological state of these patients, their family situation, and what they were hoping to gain with pathomimicry. Azúa directly confronted the patients with the diagnosis, which he demonstrated by applying an occlusive dressing. Written in a literary style typical of the times, the article includes the subjective impressions of Azúa, through which he manages to transmit a much more realistic image of these patients than that portrayed with the sterile language we tend to use in current medical literature. PMID:19775543

  15. Time machines with the compactly determined Cauchy horizon

    NASA Astrophysics Data System (ADS)

    Krasnikov, S.

    2014-07-01

    The building of a time machine, if possible at all, requires the relevant regions of spacetime to be compact (that is, physically speaking, free from sources of unpredictability such as infinities and singularities). Motivated by this argument we consider the spacetimes with the compactly determined Cauchy horizons (CDCHs), the defining property of which is the compactness of J-(U) ¯∩J+(S0), where U is an open subset of the Cauchy horizon and S0 is a Cauchy surface of the initial globally hyperbolic region Min. The following two facts are established: (1) Min has no globally hyperbolic maximal extension. This means that, by shaping appropriately a precompact portion of a globally hyperbolic region, one can force the Universe to produce either a closed causal curve, or a quasiregular singularity, whichever it abhors less. (2) Before a CDCH is formed a null geodesic appears which infinitely approaches the horizon returning again and again in the same—arbitrarily small—region. The energy of the photon moving on such a geodesic increases with each passage, or at least falls insufficiently fast. As a result, an observer located in the mentioned region would see a bunch of photons passing through his laboratory with the arbitrarily large total energy. We speculate that this phenomenon may have observable consequences.

  16. Age, Time, and Decision Making: From Processing Speed to Global Time Horizons

    PubMed Central

    Löckenhoff, Corinna E.

    2013-01-01

    Time and time perceptions are integral to decision making because any meaningful choice is embedded in a temporal context and requires the evaluation of future preferences and outcomes. The present review examines the influence of chronological age on time perceptions and horizons and discusses implications for decision making across the life span. Time influences and interacts with decision making in multiple ways. Specifically, this review examines the following topic areas: (1) processing speed and decision time, (2) internal clocks and time estimation, (3) mental representations of future time and intertemporal choice, and (4) global time horizons. For each aspect, patterns of age differences and implications for decision strategies and quality are discussed. The conclusion proposes frameworks to integrate different lines of research and identifies promising avenues for future inquiry. PMID:22023567

  17. 100 Years of the Physics of Diodes

    NASA Astrophysics Data System (ADS)

    Luginsland, John

    2013-10-01

    The Child-Langmuir Law (CL), discovered 100 years ago, gives the maximum current that can be transported across a planar diode in the steady state. As a quintessential example of the impact of space-charge shielding near a charged surface, it is central to the studies of high current diodes, such as high power microwave sources, vacuum microelectronics, electron and ion sources, and high current drivers used in high-energy density physics experiments. CL remains a touchstone of fundamental sheath physics, including contemporary studies of nano-scale quantum diodes and plasmonic devices. Its solid state analog is the Mott-Gurney law, governing the maximum charge injection in solids, such as organic materials and other dielectrics, which is important to energy devices, such as solar cells and light-emitting diodes. This paper reviews the important advances in the physics of diodes since the discovery of CL, including virtual cathode formation and extension of CL to multiple dimensions, to the quantum regime, and to ultrafast processes. We will review the influence of magnetic fields, multiple species in bipolar flow, electromagnetic and time dependent effects in both short pulse and high frequency THz limits, and single electron regimes. Transitions from various emission mechanisms (thermionic, field, and photo-emission) to the space charge limited state (CL) will be addressed, especially highlighting important simulation and experimental developments in selected contemporary areas of study. This talk will stress the fundamental physical links between the physics of beams to limiting currents in other areas, such as low temperature plasmas, laser plasmas, and space propulsion. Also emphasized is the role of non-equilibrium phenomena associated with materials and plasmas in close contact. Work supported by the Air Force Office of Scientific Research.

  18. Convergence: Human Intelligence The Next 100 Years

    ERIC Educational Resources Information Center

    Fluellen, Jerry E., Jr.

    2005-01-01

    How might human intelligence evolve over the next 100 years? This issue paper explores that idea. First, the paper summarizes five emerging perspectives about human intelligence: Howard Gardner's multiple intelligences theory, Robert Sternberg's triarchic theory of intelligence, Ellen Langer's mindfulness theory, David Perkins' learnable…

  19. Deepwater Horizon - Estimating surface oil volume distribution in real time

    NASA Astrophysics Data System (ADS)

    Lehr, B.; Simecek-Beatty, D.; Leifer, I.

    2011-12-01

    Spill responders to the Deepwater Horizon (DWH) oil spill required both the relative spatial distribution and total oil volume of the surface oil. The former was needed on a daily basis to plan and direct local surface recovery and treatment operations. The latter was needed less frequently to provide information for strategic response planning. Unfortunately, the standard spill observation methods were inadequate for an oil spill this size, and new, experimental, methods, were not ready to meet the operational demands of near real-time results. Traditional surface oil estimation tools for large spills include satellite-based sensors to define the spatial extent (but not thickness) of the oil, complemented with trained observers in small aircraft, sometimes supplemented by active or passive remote sensing equipment, to determine surface percent coverage of the 'thick' part of the slick, where the vast majority of the surface oil exists. These tools were also applied to DWH in the early days of the spill but the shear size of the spill prevented synoptic information of the surface slick through the use small aircraft. Also, satellite images of the spill, while large in number, varied considerably in image quality, requiring skilled interpretation of them to identify oil and eliminate false positives. Qualified staff to perform this task were soon in short supply. However, large spills are often events that overcome organizational inertia to the use of new technology. Two prime examples in DWH were the application of hyper-spectral scans from a high-altitude aircraft and more traditional fixed-wing aircraft using multi-spectral scans processed by use of a neural network to determine, respectively, absolute or relative oil thickness. But, with new technology, come new challenges. The hyper-spectral instrument required special viewing conditions that were not present on a daily basis and analysis infrastructure to process the data that was not available at the command

  20. Remembering Robert Goddard's vision 100 years later

    NASA Astrophysics Data System (ADS)

    Stern, David P.

    “Life, liberty, and the pursuit of happiness” —such are the goals of most of us.Yet a few always exist who feel called by a higher purpose. Society often owes them a great deal.Robert Hutchins Goddard, whose work made spaceflight possible, found his vision 100 years ago this October as a youth of 17. His family was staying on the farm of a relative, when he was asked to trim the branches of a cherry tree behind the barn.

  1. Vitamins: preparing for the next 100 years.

    PubMed

    Blumberg, Jeffrey B

    2012-10-01

    The insights gained from the last 100 years of vitamin research and applications have contributed substantially to our fundamental understanding of biology and importantly to the promotion of human health. There is no reason to think that the next 100 years will be any less fruitful if we are committed to preparing for them, particularly by changing four critical nutrition paradigms. First, we must move beyond the concept of preventing vitamin deficiencies and inadequacies to establishing health and, further, to creating optimal physiological functions. Each essential vitamin possesses different concentration thresholds for its variety of effects and the required balance necessary to achieving each has yet to be fully defined. Second, we must apply the research approaches and methods of “-omics,” systems biology, and imaging technologies to define the dynamic role of vitamins and their broad array of genomic, molecular, biochemical, and functional interactions. Such work is necessary to understand the multiplicity of vitamin actions and ultimately apply them directly at the level of the individual. Third, we must revise the concept of evidence-based nutrition away from its current hierarchical system to recognize in a comprehensive and integrated way the attributes of each type of approach to research. To adhere to a single gold standard of the randomized clinical trial ignores both how we have moved forward so productively during the last 100 years and the vital information to be gained from basic research and other human studies; further, it acts to stifle innovation in both scientific and regulatory affairs. Fourth, we must understand that changes in the supply and distribution of food during the next century are likely to be at least as dramatic as those which have occurred over this last one. For example, inevitable environmental constraints will require more food protein be derived from plant than animal sources, a shift that will directly impact the

  2. 75 FR 79961 - Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-21

    ... Gulf of Mexico Deepwater Horizon SONSat the FOSC's request. 75 FR 37712. The rule also confirmed that...; 2050-AG63 Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater.... Oil Spill Response Resources Return Time Several comments noted concerns about the return of assets...

  3. 75 FR 37712 - Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ...; 2050-AG63 Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon Oil Spill of National Significance (SONS) Response AGENCIES: Coast Guard, DHS, and Environmental... Environmental Protection Agency (EPA) temporary interim rule will suspend oil spill response time...

  4. An integral equation representation approach for valuing Russian options with a finite time horizon

    NASA Astrophysics Data System (ADS)

    Jeon, Junkee; Han, Heejae; Kim, Hyeonuk; Kang, Myungjoo

    2016-07-01

    In this paper, we first describe a general solution for the inhomogeneous Black-Scholes partial differential equation with mixed boundary conditions using Mellin transform techniques. Since Russian options with a finite time horizon are usually formulated into the inhomogeneous free-boundary Black-Scholes partial differential equation with a mixed boundary condition, we apply our method to Russian options and derive an integral equation satisfied by Russian options with a finite time horizon. Furthermore, we present some numerical solutions and plots of the integral equation using recursive integration methods and demonstrate the computational accuracy and efficiency of our method compared to other competing approaches.

  5. Horizons and non-local time evolution of quantum mechanical systems

    NASA Astrophysics Data System (ADS)

    Casadio, Roberto

    2015-04-01

    According to general relativity, trapping surfaces and horizons are classical causal structures that arise in systems with sharply defined energy and corresponding gravitational radius. The latter concept can be extended to a quantum mechanical matter state simply by means of the spectral decomposition, which allows one to define an associated "horizon wave-function". Since this auxiliary wave-function contains crucial information about the causal structure of space-time, a new proposal is formulated for the time evolution of quantum systems in order to account for the fundamental classical property that outer observers cannot receive signals from inside a horizon. The simple case of a massive free particle at rest is used throughout the paper as a toy model to illustrate the main ideas.

  6. The AOCS publications: a 100 year history

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The growth of societies and its associated publications is an indicator of how chemistry, a society such as AOCS, and the fats and oils industry have grown over time. During the late 18th century a shift from monographs to chemical periodicals occurred. Since then journals have been the preferred ...

  7. Parisian ruin over a finite-time horizon

    NASA Astrophysics Data System (ADS)

    Dębicki, Krzysztof; Hashorva, Enkelejd; Ji, LanPeng

    2016-03-01

    For a risk process $R_u(t)=u+ct-X(t), t\\ge 0$, where $u\\ge 0$ is the initial capital, $c>0$ is the premium rate and $X(t),t\\ge 0$ is an aggregate claim process, we investigate the probability of the Parisian ruin \\[ \\mathcal{P}_S(u,T_u)=\\mathbb{P}\\{\\inf_{t\\in[0,S]} \\sup_{s\\in[t,t+T_u]} R_u(s)<0\\}, \\] with a given positive constant $S$ and a positive measurable function $T_u$. We derive asymptotic expansion of $\\mathcal{P}_S(u,T_u)$, as $u\\to\\infty$, for the aggregate claim process $X$ modeled by Gaussian processes. As a by-product, we derive the exact tail asymptotics of the infimum of a standard Brownian motion with drift over a finite-time interval.

  8. Tunguska explosion- 100 years of the event

    NASA Astrophysics Data System (ADS)

    Pteancu, Mircea; Dragan, Dorian; Dohotariu, Ionel; Mafalda; Alimpie, Laurentiu; Monea, Cristian; Diaconu, Marius; Gaina, Alex; Stanescu, Octavian

    2008-06-01

    The authors discusse the Tunguska event, the well known explosion, which has occured 100 ago in the Central Siberia near the Podkamennaia Tunguska river. A number of the books and encyclopaediaes with reference to the event are reviewed. At the same time the last 2 hypotheses ennounced by prof. Ioan Nistor (gaseus Methan pouch) and prof. Edward Drobyshevsky (2H2 +O2 solid solution) are also discussed.

  9. Real-time beyond the horizon vessel detection

    NASA Astrophysics Data System (ADS)

    Roarty, Hugh J.; Smith, Michael; Glenn, Scott M.; Barrick, Donald E.

    2013-05-01

    The marine transportation system (MTS) is a vital component of the United States Economy. Waterborne cargo accounts for more than $742 billion of the nation's economy and creates employment for 13 million citizens. A disruption in this system would have far reaching consequences to the security of the country. The US National High Frequency radar network, which comprises 130 radar stations around the country, became operational in May 2009. It provides hourly measurements of surface currents to the US Coast Guard for search and rescue (SAR). This system has the capability of being a dual use system providing information for environmental monitoring as well as vessel position information for maritime security. Real time vessel detection has been implemented at two of the radar stations outside New York Harbor. Several experiments were conducted to see the amount vessel traffic that the radar could capture. The radars were able to detect a majority of the vessels that are reporting via the Automatic Identification System (AIS) as well as 30 percent of mid to large size vessels that are not reporting via AIS. The radars were able to detect vessels out to 60 km from the coast. The addition of a vessel detection capability to the National HF radar network will provide valuable information to maritime security sector. This dual use capability will fill a gap in the current surveillance of US coastal waters. It will also provide longer-range situational awareness necessary to detect and track smaller size vessels in the large vessel clutter.

  10. Nuclear and Radiochemistry: the First 100 Years

    NASA Astrophysics Data System (ADS)

    Friedlander, G.; Herrmann, G.

    This chapter gives a brief overview of the development of nuclear and radiochemistry from Mme. Curie's chemical isolation of radium toward the end of the twentieth century. The first four sections deal with fairly distinct time periods: (1) the pioneering years when the only radioactive materials available were the naturally occurring ones; (2) the decade of rapid growth and expansion of both the fundamental science and its applications following the discoveries of the neutron and artificial radioactivity; (3) the World War II period characterized by the intense exploration of nuclear fission and its ramifications; (4) what can be called the “golden era” - the 3 to 4 decades following World War II when nuclear science was generously supported and therefore flourished. In the final section, research trends pursued near the end of the century are briefly touched upon.

  11. World-sheet stability, space-time horizons and cosmic censorship

    NASA Astrophysics Data System (ADS)

    Pollock, M. D.

    2014-11-01

    Previously, we have analyzed the stability and supersymmetry of the heterotic superstring world sheet in the background Friedmann space-time generated by a perfect fluid with energy density ρ and pressure p = ( γ - 1) ρ. The world sheet is tachyon-free within the range 2/3 ≤ γ ≤ ∞, and globally supersymmetric in the Minkowski-space limit ρ = ∞, or when γ = 2/3, which is the equation of state for stringy matter and corresponds to the Milne universe, that expands along its apparent horizon. Here, this result is discussed in greater detail, particularly with regard to the question of horizon structure, cosmic censorship, the TCP theorem, and local world-sheet supersymmetry. Also, we consider the symmetric background space-time generated by a static, electrically (or magnetically) charged matter distribution of total mass and charge Q, and containing a radially directed macroscopic string. We find that the effective string mass m satisfies the inequality m 2 ≥ 0, signifying stability, provided that , which corresponds to the Reissner-Nordström black hole. The case of marginal string stability, m 2 = 0, is the extremal solution , which was shown by Gibbons and Hull to be supersymmetric, and has a marginal horizon. If , the horizon disappears, m 2 < 0, and the string becomes unstable.

  12. Forecasting geomagnetic activity at monthly and annual horizons: Time series models

    NASA Astrophysics Data System (ADS)

    Reikard, Gordon

    2015-10-01

    Most of the existing work on forecasting geomagnetic activity has been over short intervals, on the order of hours or days. However, it is also of interest to predict over longer horizons, ranging from months to years. Forecasting tests are run for the Aa index, which begins in 1868 and provides the longest continuous records of geomagnetic activity. This series is challenging to forecast. While it exhibits cycles at 11-22 years, the amplitude and period of the cycles varies over time. There is also evidence of discontinuous trending: the slope and direction of the trend change repeatedly. Further, at the monthly resolution, the data exhibits nonlinear variability, with intermittent large outliers. Several types of models are tested: regressions, neural networks, a frequency domain algorithm, and combined models. Forecasting tests are run at horizons of 1-11 years using the annual data, and 1-12 months using the monthly data. At the 1-year horizon, the mean errors are in the range of 13-17 percent while the median errors are in the range of 10-14 percent. The accuracy of the models deteriorates at longer horizons. At 5 years, the mean errors lie in the range of 21-23 percent, and at 11 years, 23-25 percent. At the 1 year horizon, the most accurate forecast is achieved by a combined model, but over longer horizons (2-11 years), the neural net dominates. At the monthly resolution, the mean errors are in the range of 17-19 percent at 1 month, while the median errors lie in a range of 14-17 percent. The mean error increases to 23-24 percent at 5 months, and 25 percent at 12 months. A model combining frequency and time domain methods is marginally better than regressions and neural networks alone, up to 11 months. The main conclusion is that geomagnetic activity can only be predicted to within a limited threshold of accuracy, over a given range of horizons. This is consistent with the finding of irregular trends and cycles in the annual data and nonlinear variability in

  13. 100 years of sedimentation study by the USGS

    USGS Publications Warehouse

    Glysson, G. Douglas

    1989-01-01

    On January 15, 1889, the U.S. Geological Survey began collecting sediment data on the Rio Grande at Embudo, New Mexico. During the past 100 years the U.S. Geological Survey's Water Resources Division (WRD) has collected daily sediment data at more than 1,200 sites. Projects have addressed the problems associated with reservoir construction, agricultural irrigation projects, energy production, and transport and deposition of pollutants sorbed to sediments. The Survey has been active as a charter member of the Federal Interagency Sediment Project and currently has three full-time hydrologists working on the project. The WRD's sediment-research projects have covered a wide variety of subjects from the fundamental theories of resistance to flow and sediment transport in alluvial channels to lunar erosion mechanisms.

  14. Revisiting the 100 Year Old Radioactivity Lectures of Frederick Soddy

    NASA Astrophysics Data System (ADS)

    Hampton, Christine

    2008-04-01

    Between 1908 and 1922, Frederick Soddy, MA., FRS (Dr. Lee`s Professor of Inorganic and Physical Chemistry, Univ. of Oxford) published four editions of a compendium of his experimental lectures delivered at the University of Glasgow, under the title ``The Interpretation of Radium, and the Structure of the Atom''. Professor Soddy taught his students about `radium writing' and the emanation of radium. He presented a radium clock designed by Professor Strutt; showed students `Pleochroic Halos'; and described the separation of `ionium' from its isotope, thorium. The process of constructing a cohesive logic to empirical observations of this newly discovered phenomenon of radioactivity was a challenging one. Some aspects did not stand the test of time. However, revisiting these lectures after 100 years gives us fascinating insight into the mental processes of the early pioneers in radioactivity.

  15. Continuous-Time Mean-Variance Portfolio Selection with Random Horizon

    SciTech Connect

    Yu, Zhiyong

    2013-12-15

    This paper examines the continuous-time mean-variance optimal portfolio selection problem with random market parameters and random time horizon. Treating this problem as a linearly constrained stochastic linear-quadratic optimal control problem, I explicitly derive the efficient portfolios and efficient frontier in closed forms based on the solutions of two backward stochastic differential equations. Some related issues such as a minimum variance portfolio and a mutual fund theorem are also addressed. All the results are markedly different from those in the problem with deterministic exit time. A key part of my analysis involves proving the global solvability of a stochastic Riccati equation, which is interesting in its own right.

  16. HORIZON SENSING

    SciTech Connect

    Larry G. Stolarczyk, Sc.D.

    2002-07-31

    Real-time horizon sensing (HS) on continuous mining (CM) machines is becoming an industry tool. Installation and testing of production-grade HS systems has been ongoing this quarter at Oxbow Mining Company, Monterey Coal Company (EXXON), FMC Trona, Twentymile Coal Company (RAG America), and SASOL Coal. Detailed monitoring of system function, user experience, and mining benefits is ongoing. All horizon sensor components have finished MSHA (United States) and IEC (International) certification.

  17. Technique for estimating depths of 100-year floods in Pennsylvania

    USGS Publications Warehouse

    Flippo, Herbert N., Jr.

    1990-01-01

    Techniques are developed for estimating 100-year flood depths in natural channels of unregulated Pennsylvania streams that drain less than 2,200 square miles. Equations and graphs are presented relating the depth of the 100-year flood above median stage and drainage area in five defined hydrologic areas in the State. Another graph defines the relation between drainage area and median depth of flow over the low point of riffles. Thus 100-year depths on riffles can be estimated by summing depth values derived from two simple relations.

  18. Incorporating a Time Horizon in Rate-of-Return Estimations: Discounted Cash Flow Model in Electric Transmission Rate Cases

    SciTech Connect

    Chatterjee, Bishu; Sharp, Peter A.

    2006-07-15

    Electric transmission and other rate cases use a form of the discounted cash flow model with a single long-term growth rate to estimate rates of return on equity. It cannot incorporate information about the appropriate time horizon for which analysts' estimates of earnings growth have predictive powers. Only a non-constant growth model can explicitly recognize the importance of the time horizon in an ROE calculation. (author)

  19. 100-Year Flood-It's All About Chance

    USGS Publications Warehouse

    Holmes, Jr., Robert R.; Dinicola, Karen

    2010-01-01

    In the 1960's, the United States government decided to use the 1-percent annual exceedance probability (AEP) flood as the basis for the National Flood Insurance Program. The 1-percent AEP flood was thought to be a fair balance between protecting the public and overly stringent regulation. Because the 1-percent AEP flood has a 1 in 100 chance of being equaled or exceeded in any 1 year, and it has an average recurrence interval of 100 years, it often is referred to as the '100-year flood'. The term '100-year flood' is part of the national lexicon, but is often a source of confusion by those not familiar with flood science and statistics. This poster is an attempt to explain the concept, probabilistic nature, and inherent uncertainties of the '100-year flood' to the layman.

  20. Mean-Variance Hedging on Uncertain Time Horizon in a Market with a Jump

    SciTech Connect

    Kharroubi, Idris; Lim, Thomas; Ngoupeyou, Armand

    2013-12-15

    In this work, we study the problem of mean-variance hedging with a random horizon T∧τ, where T is a deterministic constant and τ is a jump time of the underlying asset price process. We first formulate this problem as a stochastic control problem and relate it to a system of BSDEs with a jump. We then provide a verification theorem which gives the optimal strategy for the mean-variance hedging using the solution of the previous system of BSDEs. Finally, we prove that this system of BSDEs admits a solution via a decomposition approach coming from filtration enlargement theory.

  1. Optimal Consumption in a Brownian Model with Absorption and Finite Time Horizon

    SciTech Connect

    Grandits, Peter

    2013-04-15

    We construct {epsilon}-optimal strategies for the following control problem: Maximize E[{integral}{sub [0,{tau})}e{sup -{beta}s} dC{sub s}+e{sup -{beta}{tau}}X{sub {tau}}] , where X{sub t}=x+{mu}t+{sigma}W{sub t}-C{sub t}, {tau}{identical_to}inf{l_brace}t>0|X{sub t}=0{r_brace} Logical-And T, T>0 is a fixed finite time horizon, W{sub t} is standard Brownian motion, {mu}, {sigma} are constants, and C{sub t} describes accumulated consumption until time t. It is shown that {epsilon}-optimal strategies are given by barrier strategies with time-dependent barriers.

  2. [The 20th century: 100 years of misfortune and splendor].

    PubMed

    Urdaneta-Carruyo, Eliéxer

    2005-01-01

    The 20th century has been one of the most intense and convulsive periods in the History of humanity. A century of paradoxes and contrasts, it began with optimism, it witnessed the apocalypse of two world wars, and finished with unimaginable scientific progress that gave us a new civilization that we cannot yet grasp. In this century, significant events happened that shaped our time and projected their results toward an immediate future. Some of these were providential in understanding man's life, fighting against illnesses and prolonging life, and others were of undeniable social importance for humanity. Some knowledge was based on the work of others. Philosophy was embedded in mathematics, as was science in philosophy, while politics and the economy exercised so decisive an influence in our way of feeling and living that culture and society were affected to the core. Within that century the biggest technological revolution of all the time was also created, as transcendent as it was unimaginable, which put mankind on the road to the stars with the moon landing and in the process created the information society whose signature symbol, the internet, emerged as a new demiurge. However, the 20th century, with all its misfortune and splendor, paradoxes and contrasts, creation and destruction, was the most transcendent in the whole of history and it bequeaths to the future a promising horizon in the search for a renovated meaning of life and a yearning for peaceful coexistence for the whole humanity. PMID:15754756

  3. A receding horizon scheme for discrete-time polytopic linear parameter varying systems in networked architectures

    NASA Astrophysics Data System (ADS)

    Franzè, Giuseppe; Lucia, Walter; Tedesco, Francesco

    2014-12-01

    This paper proposes a Model Predictive Control (MPC) strategy to address regulation problems for constrained polytopic Linear Parameter Varying (LPV) systems subject to input and state constraints in which both plant measurements and command signals in the loop are sent through communication channels subject to time-varying delays (Networked Control System (NCS)). The results here proposed represent a significant extension to the LPV framework of a recent Receding Horizon Control (RHC) scheme developed for the so-called robust case. By exploiting the parameter availability, the pre-computed sequences of one- step controllable sets inner approximations are less conservative than the robust counterpart. The resulting framework guarantees asymptotic stability and constraints fulfilment regardless of plant uncertainties and time-delay occurrences. Finally, experimental results on a laboratory two-tank test-bed show the effectiveness of the proposed approach.

  4. Spring wheat gliadins: Have they changed in 100 years?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been many hard red spring (HRS) wheat cultivars released in North Dakota during the last 100 years. These cultivars have been improved for various characteristics such as, adaptation to weather conditions, high yield, and good milling and baking quality. The objectives of this study wer...

  5. 100 Years of Commitment to Children: Change and Continuity.

    ERIC Educational Resources Information Center

    Shore, Rima

    The Foundation for Child Development (FCD) is the oldest philanthropy in the nation focused on improving the life prospects of children. This booklet, produced for FCD's centennial, describes the organization's origins and changes during the past 100 years. The booklet's sections, which include photographs, quotes, and a timeline, are: (1) "The…

  6. Centennial Calendar- 100 Years of the American Phytopathological Society

    Technology Transfer Automated Retrieval System (TEKTRAN)

    I edited a 40-page publication (calendar) that covered 18 chapters written by members of our society. This covered pioneering researchers, departments, and epidemics of the last 100 years of plant pathology in the U. S. This was given to all members of the American Phytopathological Society who att...

  7. MARKOV: A methodology for the solution of infinite time horizon MARKOV decision processes

    USGS Publications Warehouse

    Williams, B.K.

    1988-01-01

    Algorithms are described for determining optimal policies for finite state, finite action, infinite discrete time horizon Markov decision processes. Both value-improvement and policy-improvement techniques are used in the algorithms. Computing procedures are also described. The algorithms are appropriate for processes that are either finite or infinite, deterministic or stochastic, discounted or undiscounted, in any meaningful combination of these features. Computing procedures are described in terms of initial data processing, bound improvements, process reduction, and testing and solution. Application of the methodology is illustrated with an example involving natural resource management. Management implications of certain hypothesized relationships between mallard survival and harvest rates are addressed by applying the optimality procedures to mallard population models.

  8. Pluto's Atmosphere at the Time of the New Horizons Flyby from the 29-JUN-2015 Occultation

    NASA Astrophysics Data System (ADS)

    Young, E.; Skrutskie, M.; Wasserman, L.; Howell, R.; Young, L.; Olkin, C.; Buie, M.

    2015-10-01

    Pluto is expected to occult a star on 29-JUN-2015, only two weeks before the scheduled New Horizons flyby on Pluto on 14-JUL-2015. This occultation should be remarkable for several reasons in addition to its synergy with the spacecraft observations. First, the occulted star is by far the brightest ever to be observed in a Pluto occultation: its V-mag is 12.10 ± 0.03, about ten times brighter than Pluto itself. We are deploying a wide array of telescopes to obtain quality lightcurves at 10 Hz, sufficient to resolve vertical atmospheric structure (e.g., gravity waves) at the 2.5-km scale over a range of radii from about 1195 to 1300 km. Second, we plan to obtain lighcurves in infrared wavelengths near 1.7 μm, where the star's H-mag (about 11) is bright enough to provide useful signal-to-noise ratios, albeit at slower cadences near 1 Hz (about two points per scale height). The combination of simultaneous IR and visible wavelength lightcurves should address the decades-old question: is there haze in Pluto's atmosphere, and if so, what is its opacity? New Horizons should image haze layers in reflected light as the occultation quantifies haze extinction in transmitted light: the combination could potentially let us solve for haze phase functions. Third, the current predicted shadow path is centered over much of New Zealand. We plan to deploy three portable telescopes in New Zealand to locations that are candidates for observing central flashes. If successful, these lightcurves can tell us (a) the oblateness of Pluto's atmosphere and (b) the detailed density gradient profile at radii near 1215 km, which (in turn) is a function of trace abundances of CO and CH4 a few tens of km above Pluto's surface. We will report on lightcurves obtained on 29-JUN- 2015, the column abundance of Pluto's atmosphere just two weeks before the New Horizons flyby, the detection (or not) of haze, and - if central flashes are obtained - the oblateness of Pluto's atmosphere.

  9. A universal celebration: 100 years of Korotkoff sounds, 1905 - 2005.

    PubMed

    Naqvi, Nasim H

    2005-12-01

    The measurement of systolic and diastolic blood pressure by auscultation was first described 100 years ago, when a young Russian army doctor, Nicolai Sergeevich Korotkoff, addressed a meeting at the Medical Academy of St. Petersburg on 8th November 1905. During the last hundred years, Korotkoff's contribution has proved to be one of the most useful methods in the diagnosis, treatment, monitoring and prevention of life threatening cardiovascular ailments and the centenary of his discovery should be celebrated universally. PMID:17153281

  10. HORIZON SENSING

    SciTech Connect

    Larry G. Stolarczyk

    2003-03-18

    program began development in 1998 and experienced three major design phases. The final version, termed HS-3, was commissioned in 2000 with the assistance of the DOE-Mining Industry of the Future program, commercialized in 2002, and has been used 14 times in 12 different mines within the United States. The Horizon Sensor has applications in both underground and surface mining operations. This technology is primarily used in the coal industry, but is also used to mine trona and potash. All horizon sensor components have Mine Safety and Health Administration (MSHA) (United States) and IEC (International) certification. Horizon Sensing saves energy by maximizing cutting efficiency, cutting only desired material. This desired material is cleaner fuel, therefore reducing pollutants to the atmosphere when burned and burning more efficiently. Extracting only desired material increases productivity by reducing or eliminating the cleaning step after extraction. Additionally, this technology allows for deeper mining, resulting in more material gained from one location. The remote sensing tool allows workers to operate the machinery away from the hazards of cutting coal, including noise, breathing dust and gases, and coal and rock splintering and outbursts. The HS program has primarily revolved around the development of the technology. However, the end goal of the program has always been the commercialization of the technology and only within the last 2 years of the program has this goal been realized. Real-time horizon sensing on mining machines is becoming an industry tool. Detailed monitoring of system function, user experience, and mining benefits is ongoing.

  11. Ernst Mach on the vestibular organ 100 years ago.

    PubMed

    Henn, V; Young, L R

    1975-01-01

    Ernst Mach (1838-1916) performed pioneering research on vestibular function 100 years ago. His experiments were mainly psychophysical and included measurements of threshold and study of the vestibular-visual interaction. Contrary to general belief, he concluded that the adequate stimulus for the semicircular canals must be pressure. He presented evidence specifically against the sustained endolymph flow theory of Breuer (1874) and Crum Brown (1874), with which he is frequently associated. Excerpts from his publications are given and their relevance to current research is discussed. PMID:1093083

  12. Ragnar Granit 100 years--memories and reflections.

    PubMed

    Kernell, D

    2000-12-01

    The Swedish-Finnish Nobel laureate Ragnar Granit, born 100 years ago, is commemorated in a brief article by one of his former PhD students and collaborators. After a short account of Granit's life and scientific career, special attention is given to Granit's role as a teacher in research training and his published thoughts on this matter, partly reflecting Granit's own experience as a "postdoc" in the laboratory of Sherrington (Oxford). The article includes personal recollections of how it was to work together with Granit in his laboratory. PMID:11232369

  13. ''Illusion of control'' in Time-Horizon Minority and Parrondo Games

    NASA Astrophysics Data System (ADS)

    Satinover, J. B.; Sornette, D.

    2007-12-01

    Human beings like to believe they are in control of their destiny. This ubiquitous trait seems to increase motivation and persistence, and is probably evolutionarily adaptive [J.D. Taylor, S.E. Brown, Psych. Bull. 103, 193 (1988); A. Bandura, Self-efficacy: the exercise of control (WH Freeman, New York, 1997)]. But how good really is our ability to control? How successful is our track record in these areas? There is little understanding of when and under what circumstances we may over-estimate [E. Langer, J. Pers. Soc. Psych. 7, 185 (1975)] or even lose our ability to control and optimize outcomes, especially when they are the result of aggregations of individual optimization processes. Here, we demonstrate analytically using the theory of Markov Chains and by numerical simulations in two classes of games, the Time-Horizon Minority Game [M.L. Hart, P. Jefferies, N.F. Johnson, Phys. A 311, 275 (2002)] and the Parrondo Game [J.M.R. Parrondo, G.P. Harmer, D. Abbott, Phys. Rev. Lett. 85, 5226 (2000); J.M.R. Parrondo, How to cheat a bad mathematician (ISI, Italy, 1996)], that agents who optimize their strategy based on past information may actually perform worse than non-optimizing agents. In other words, low-entropy (more informative) strategies under-perform high-entropy (or random) strategies. This provides a precise definition of the “illusion of control” in certain set-ups a priori defined to emphasize the importance of optimization.

  14. Progress of Cometary Science in the Past 100 Years

    NASA Technical Reports Server (NTRS)

    Sekanina, Zdenek

    1999-01-01

    Enormous strides made by cometary science during the 20th century defy any meaningful comparison of its state 100 years ago and now. The great majority of the subfields enjoying much attention nowadays did not exist in the year 1900. Dramatic developments, especially in the past 30-50 years, have equally affected observational and theoretical studies of comets. The profound diversification of observing techniques has been documented by the ever widening limits on the electromagnetic spectrum covered. While the time around 1900 marked an early period of slow and painful experimentation with photographic methods in cometary studies, observations of comets from the x-ray region to the radio waves have by now become routine. Many of the new techniques, and all those involved with the wavelengths shorter than about 300 nm, were made possible by another major breakthrough of this century - observing from space. Experiments on dedicated Earth-orbiting satellites as well as several deep-space probes have provided fascinating new information on the nature and makeup of comets. In broader terms, much of the progress has been achieved thanks to fundamental discoveries and major advances in electronics, whose applications resulted in qualitatively new instruments (e.g. radiotelescopes) and sensors or detectors (e.g. CCD arrays). The most universal effect on the entire cometary science, from observing to data handling to quantitative interpretations, has been, as in any other branch of science, due to the introduction of electronic computers, with their processing capabilities not only unheard of, but literally unimaginable, in the age of classical desk calculators. As if all this should not be enough, the today's generations of comet scientists have, in addition, been blessed with nature's highly appreciated cooperation. Indeed, in the span of a dozen years, between 1985 and 1997, we were privileged to witness four remarkable cometary events: (i) a return of Halley

  15. Extending dry storage of spent LWR fuel for 100 years.

    SciTech Connect

    Einziger, R. E.

    1998-12-16

    Because of delays in closing the back end of the fuel cycle in the U.S., there is a need to extend dry inert storage of spent fuel beyond its originally anticipated 20-year duration. Many of the methodologies developed to support initial licensing for 20-year storage should be able to support the longer storage periods envisioned. This paper evaluates the applicability of existing information and methodologies to support dry storage up to 100 years. The thrust of the analysis is the potential behavior of the spent fuel. In the USA, the criteria for dry storage of LWR spent fuel are delineated in 10 CFR 72 [1]. The criteria fall into four general categories: maintain subcriticality, prevent the release of radioactive material above acceptable limits, ensure that radiation rates and doses do not exceed acceptable levels, and maintain retrievability of the stored radioactive material. These criteria need to be considered for normal, off-normal, and postulated accident conditions. The initial safety analysis report submitted for licensing evaluated the fuel's ability to meet the requirements for 20 years. It is not the intent to repeat these calculations, but to look at expected behavior over the additional 80 years, during which the temperatures and radiation fields are lower. During the first 20 years, the properties of the components may change because of elevated temperatures, presence of moisture, effects of radiation, etc. During normal storage in an inert atmosphere, there is potential for the cladding mechanical properties to change due to annealing or interaction with cask materials. The emissivity of the cladding could also change due to storage conditions. If there is air leakage into the cask, additional degradation could occur through oxidation in breached rods, which could lead to additional fission gas release and enlargement of cladding breaches. Air in-leakage could also affect cover gas conductivity, cladding oxidation, emissivity changes, and

  16. Space-time curvature and the cosmic horizon: derivations using the Newtonian world and the Friedmann-Robertson-Walker metric

    NASA Astrophysics Data System (ADS)

    Öztaş, A. M.; Smith, M. L.

    2015-05-01

    Several relationships describing the distance versus time dependence of the cosmic horizon (Rh) for an expanding universe have been published within the past two decades. Some are based on the special conditions, including a flat universe geometry, and when applied for calculation return significantly different values. We present our derivation beginning with Newtonian world then following the Friedmann model from the viewpoint of an observer located at the origin of an expanding spherical, homogeneously matter-dominated universe; both geometrically flat and allowing space-time curvature. Our derivations for the cosmic horizon at the speed of light allow examination for the effects of matter density and space-time curvature. We also compare the fitness of several current models, including the recently proposed Rh = ct universe against the demands of the 580 Union 2.1 Type Ia supernovae distance and redshift data with uncommon, proper attention paid to data transformation and observational errors.

  17. GOM Deepwater Horizon Oil Spill: A Time Series Analysis of Variations in Spilled Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Palomo, C. M.; Yan, B.

    2013-12-01

    An estimated amount of 210 million gallons of crude oil was released into the Gulf of Mexico (GOM) from April 20th to July 15th 2010 during the Deepwater Horizon oil rig explosion. The spill caused a tremendous financial, ecological, environmental and health impact and continues to affect the GOM today. Variations in hydrocarbons including alkanes, hopanes and poly-cyclic aromatic hydrocarbons (PAHs) can be analyzed to better understand the oil spill and assist in oil source identification. Twenty-one sediment samples*, two tar ball samples and one surface water oil sample were obtained from distinct locations in the GOM and within varying time frames from May to December 2010. Each sample was extracted through the ASE 200 solvent extractor, concentrated down under nitrogen gas, purified through an alumina column, concentrated down again with nitrogen gas and analyzed via GC X GC-TOF MS. Forty-one different hydrocarbons were quantified in each sample. Various hydrocarbon 'fingerprints,' such as parental :alkylate PAH ratios, high molecular weight PAHs: low molecular weight alkane ratios, and carbon preference index were calculated. The initial objective of this project was to identify the relative hydrocarbon contributions of petrogenic sources and combustion sources. Based on the calculated ratios, it is evident that the sediment core taken in October of 2010 was greatly affected by combustion sources. Following the first month of the spill, oil in the gulf was burned in attempts to contain the spill. Combustion related sources have quicker sedimentation rates, and hydrocarbons from a combustion source essentially move into deeper depths quicker than those from a petrogenic source, as was observed in analyses of the October 2010 sediment. *Of the twenty-one sediment samples prepared, nine were quantified for this project.

  18. An experimental study of the influence of limited time horizon on positivity effects among young adults using eye-tracking.

    PubMed

    Cypryańska, Marzena; Krejtz, Izabela; Jaskółowska, Aleksandra; Kulawik, Alicja; Żukowska, Aleksandra; De Zavala, Agnieszka Golec; Niewiarowski, Jakub; Nezlek, John B

    2014-12-01

    Compared to younger adults, older adults attend more to positive stimuli, a positivity effect. Older adults have limited time horizons, and they focus on maintaining positive affect, whereas younger adults have unlimited time horizons, and they focus on acquiring knowledge and developing skills. Time horizons were manipulated by asking participants (66 young adults, M age = 20.5 yr., SD = 1.2) to think that their lives would end in three years. Some participants focused on what they would do in these three years (life focus), whereas others focused on the fact that they would die in three years (death focus). Attentional biases to facial expressions of happiness, sadness, fear, anger, and disgust were measured. Participants viewed 20 slides including pairings of a happy face with each of the negative emotions. The dependent measure was the relative attention paid to the faces on each slide. Participants in the experimental conditions exhibited a positivity effect compared to participants in the control condition, although some results suggested that this effect was weaker in the death focus condition than in the life focus condition. PMID:25457091

  19. 100 years of Belgian rainfall: are there trends?

    PubMed

    Vaes, G; Willems, P; Berlamont, J

    2002-01-01

    In 1999 the digitisation of old rainfall records of measurements at Uccle (Belgium) was completed, which resulted in a unique rainfall series of 100 years (period 1898-1997). This is an ideal opportunity to search for trends in the rainfall over the last century. Large variations in rainfall probability over the century have been observed. For small aggregation levels there is a small decrease in extreme rainfall events over the century. For large aggregation levels there is a more explicit increase in extreme rainfall. Because the rainfall on seasonal aggregation level is only slightly increased, the increase in extreme rainfall events for aggregation levels between a few days and a few months can only occur due to larger clustering. However, the final conclusion is that no significant trend can be observed. A pure random variation of the rainfall can cause equally large variations. This does not exclude a possible trend in flooding frequency, due to the strong increase in urbanisation over the last century. PMID:11888184

  20. Colloquium: 100 years of mass spectrometry: Perspectives and future trends

    NASA Astrophysics Data System (ADS)

    Maher, Simon; Jjunju, Fred P. M.; Taylor, Stephen

    2015-01-01

    Mass spectrometry (MS) is widely regarded as the most sensitive and specific general purpose analytical technique. More than a century has passed for MS since the ground-breaking work of Nobel laureate Sir Joseph John Thomson in 1913. This Colloquium aims to (1) give an historical overview of the major instrumentation achievements that have driven mass spectrometry forward in the past century, including those leading up to the initial work of Thomson, (2) provide the nonspecialist with an introduction to MS, and (3) highlight some key applications of MS and explore the current and future trends. Because of the vastness of the subject area and quality of the manifold research efforts that have been undertaken over the last 100 years, which have contributed to the foundations and subsequent advances in mass spectrometry, it should be understood that not all of the key contributions may have been included in this Colloquium. Mass spectrometry has embraced a multitude of scientific disciplines and to recognize all of the achievements is an impossible task, such has been the diverse impact of this invaluable technique. Scientific progress is usually made via the cumulative effort of a large number of researchers; the achievements reported herein are only a representation of that effort.

  1. Pedernales oilfield, eastern Venezuela: The first 100 years

    SciTech Connect

    Gluyas, J.; Oliver, J.; Wilson, W.

    1996-08-01

    Petroleum seeps and surface tar mats attracted oil explorers to Pedernales in eastern Venezuela 100 years ago. Commercial production from the Pedernales Field was established by Creole in 1933. In three production periods, broken by WWII and the end of the Creole-Texaco refining contract, Creole and Lagoven produced about 60 MMSTB from about 60 wells in about 60 years. Peak production was in the late 1950s, when the field delivered 12,000 BOPD. Production was stopped in 1986. In March 1993, BP Venezuela acquired the license to reactivate Pedernales on behalf of Lagoven, and BP`s first well in the field was drilled in August 1994. A second was completed in early 1995. The production from each well was sufficiently encouraging for commerciality to be declared in March 1995. Phase 1 of the field reactivation demanded a production rate of 11,500 BOPD. As of now (September, 1995) six wells, including one gas disposal well, have been completed. Wells have been placed using a combination of old well data and mapping based on a close spaced 2D seismic survey shot in early 1994. Results from these first few wells indicate that the required production rate will be achieved despite severely depleted reservoir pressures. This paper tells the story of reactivation and re-evaluation of one of eastern Venezuela`s oldest oilfields.

  2. Slope restoration for a 100-year old canal

    SciTech Connect

    Skaggs, R.L.; Lewis, S.W.; Liebersbach, D.C.

    1995-12-31

    Turlock Irrigation District (TID) is located in the northern portion of the fertile San Joaquin Valley of California. TID`s primary water supply is conveyed from the 100-year-old LaGrange Diversion Dam via their historic Upper Main Canal. The original canal was constructed by excavating into slate bedrock for the uphill (cut) bank, and constructing unmortared rock walls and rock fill for the downhill (fill) embankment; the excavation was then lined with concrete. Soil fill raises of the downhill embankment over the last 30 years have reduced the slope stability to unacceptable levels in the steepest embankment areas. In March of 1994, two surficial slides prompted investigation of the long term embankment stability in the Warehouse Slide Area. Based on results of analysis for various stabilization scenarios, TID chose a stabilization method which included: (1) excavation of an access bench below the existing canal, (2) installation of steel pipe piles through the existing rock fill and into the bedrock, (3) construction of a mechanically stabilized earth (MSE) retaining wall and (4) construction of a soil-cement canal roadway pavement. The design was chosen by the owner because of cost competitiveness compared to other design alternatives and because the construction sequence allowed uninterrupted use of the canal. By using local river cobble for the MSE wall facing material, TID met the desired 50-year design life of the repair while maintaining the area`s historic visual features.

  3. Overuse syndrome in musicians--100 years ago. An historical review.

    PubMed

    Fry, H J

    Overuse syndrome in musicians was extensively reported 100 years ago. The clinical features and results of treatment, which were recorded in considerable detail, match well the condition that is described today. The medical literature that is reviewed here extends from 1830 to 1911 and includes 21 books and 54 articles from the English language literature, apart from two exceptions; however, the writers of the day themselves reviewed French, German and Italian literature on the subject. The disorder was said to result from the overuse of the affected parts. Two theories of aetiology, not necessarily mutually exclusive, were argued. The central theory regarded the lesion as being in the central nervous system, the peripheral theory implied a primary muscle disorder. No serious case was put forward for a psychogenic origin, though emotional factors were believed to aggravate the condition. Advances in musical instrument manufacture--particularly the development of the concert piano and the clarinet--may have played a part in the prevalence of overuse syndrome in musicians. Total rest from the mechanical use of the hand was the only effective treatment recorded. PMID:3540544

  4. Optimal stock liquidation in a regime switching model with finite time horizon

    NASA Astrophysics Data System (ADS)

    Pemy, M.; Zhang, Q.

    2006-09-01

    This paper is concerned with a finite-horizon optimal selling rule. A set of geometric Brownian motions coupled by a finite-state Markov chain is used to characterize stock price movements. Given a fixed transaction fee, the optimal selling rule can be obtained by solving an optimal stopping problem. The corresponding value function is shown to be the unique viscosity solution to the associated HJB equations. Numerical solutions to these equations and their convergence are obtained. A numerical example is presented to illustrate the results.

  5. Emergence of time-horizon invariant correlation structure in financial returns by subtraction of the market mode

    NASA Astrophysics Data System (ADS)

    Borghesi, Christian; Marsili, Matteo; Miccichè, Salvatore

    2007-08-01

    We investigate the emergence of a structure in the correlation matrix of assets’ returns as the time horizon over which returns are computed increases from the minutes to the daily scale. We analyze data from different stock markets (New York, Paris, London, Milano) and with different methods. In addition to the usual correlations, we also analyze those obtained by subtracting the dynamics of the “center of mass” (i.e., the market mode). We find that when the center of mass is not removed the structure emerges, as the time horizon increases, from splitting a single large cluster into smaller ones. By contrast, when the market mode is removed the structure of correlations observed at the daily scale is already well defined at very high frequency ( 5min in the New York Stock Exchange). Moreover, this structure accounts for 80% of the classification of stocks in economic sectors. Similar results, though less sharp, are found for the other markets. We also find that the structure of correlations in the overnight returns is markedly different from that of intraday activity.

  6. Time-lapse borehole radar for monitoring rainfall infiltration through podosol horizons in a sandy vadose zone

    NASA Astrophysics Data System (ADS)

    Strobach, Elmar; Harris, B. D.; Dupuis, J. C.; Kepic, A. W.

    2014-03-01

    The shallow aquifer on the Gnangara Mound, north of Perth, Western Australia, is recharged by winter rainfall. Water infiltrates through a sandy Podosol where cemented accumulation (B-) horizons are common. They are water retentive and may impede recharge. To observe wetting fronts and the influence of soil horizons on unsaturated flow, we deployed time-lapse borehole radar techniques sensitive to soil moisture variations during an annual recharge cycle. Zero-offset crosswell profiling (ZOP) and vertical radar profiling (VRP) measurements were performed at six sites on a monthly basis before, during, and after annual rainfall in 2011. Water content profiles are derived from ZOP logs acquired in closely spaced wells. Sites with small separation between wells present potential repeatability and accuracy difficulties. Such problems could be lessened by (i) ZOP saturated zone velocity matching of time-lapse curves, and (ii) matching of ZOP and VRP results. The moisture contents for the baseline condition and subsequent observations are computed using the Topp relationship. Time-lapse moisture curves reveal characteristic vadose zone infiltration regimes. Examples are (I) full recharge potential after 200 mm rainfall, (II) delayed wetting and impeded recharge, and (III) no recharge below 7 m depth. Seasonal infiltration trends derived from long-term time-lapse neutron logging at several sites are shown to be comparable with infiltration trends recovered from time-lapse crosswell radar measurements. However, radar measurements sample a larger volume of earth while being safer to deploy than the neutron method which employs a radioactive source. For the regime (III) site, where time-lapse radar indicates no net recharge or zero flux to the water table, a simple water balance provides an evapotranspiration value of 620 mm for the study period. This value compares favorably to previous studies at similar test sites in the region. Our six field examples demonstrate

  7. The State of Pluto's Bulk Atmosphere at the Time of the New Horizons Encounter

    NASA Astrophysics Data System (ADS)

    Resnick, Aaron C.; Barry, T.; Buie, M. W.; Carriazo, C. Y.; Cole, A.; Gault, D.; Giles, B.; Giles, D.; Hartig, K.; Hill, K.; Howell, R. R.; Hudson, G.; Loader, B.; Mackie, J.; Nelson, M.; Olkin, C.; Register, J.; Rodgers, T.; Sicardy, B.; Skrutskie, M.; Verbiscer, A.; Wasserman, L.; Watson, C.; Young, E.; Young, L.; Zalucha, A.

    2015-11-01

    On 29-JUL-2015, our team - plus many critical amateur astronomers - observed a stellar occultation by Pluto from sites in Australia and New Zealand. This event was remarkable for two reasons: it preceded the New Horizons flyby of Pluto by just two weeks, and the occulted star was about 10x brighter than Pluto itself, by far the brightest Pluto occultation event observed to date. The separation of ground sites spanned nearly 900 km with respect to the central chord, allowing a good geometric solution for the shadow path. The lightcurves show some inflection points and broad "fangs" that are characteristic of perturbations in the temperature profile. Preliminary fits show that the temperature profile derived from a 2006 occultation (Young et al. 2008) reproduces the 29-JUN-2015 lightcurves well. Assuming a surface radius of 1187 km for Pluto, we find that the surface pressure is 18 +/- 3 µbar. This pressure indicates that Pluto's surface has not yet started to cool down, despite a decrease in absorbed solar flux of more than 17% since perihelion in 1988. A surface pressure of 18 µbar would correspond to a nitrogen ice surface temperature of 38.0 K.References:Young, E.F., et al. "Vertical Structure in Pluto's Atmosphere from the 2006 June 12 Stellar Occultation," AJ 136 1757-1769 (2008)

  8. Water Stress on U.S. Power Production at Decadal Time Horizons

    NASA Astrophysics Data System (ADS)

    Ganguli, P.; Kumar, D.; Yun, J.; Short, G.; Klausner, J.; Ganguly, A. R.

    2014-12-01

    Thermoelectric power production at risk, owing to current and projected water scarcity and rising stream temperatures, is assessed for the continental United States (US) at decadal scales. Regional water scarcity is driven by climate variability and change, as well as by multi-sector water demand. While a planning horizon of zero to about thirty years is occasionally prescribed by stakeholders, the challenges to risk assessment at these scales include the difficulty in delineating decadal climate trends from intrinsic natural or multiple model variability. Current generation global climate or earth system models are not credible at the spatial resolutions of power plants, especially for surface water quantity and stream temperatures, which further exacerbates the assessment challenge. Population changes, which are anyway difficult to project, cannot serve as adequate proxies for changes in the water demand across sectors. The hypothesis that robust assessments of power production at risks are possible, despite the uncertainties, has been examined as a proof of concept. An approach is presented for delineating water scarcity and temperature from climate models, observations and population storylines, as well as for assessing power production at risk by examining geospatial correlations of power plant locations within regions where the usable water supply for energy production happens to be scarcer and warmer. Acknowledgment: Funding provided by US DOE's ARPA-E through Award DE-AR0000374.

  9. 100 Years of the Quantum - the Glory and the Shame

    NASA Astrophysics Data System (ADS)

    Wheeler, John Archibald

    2001-03-01

    What is the greatest mystery that stands out on the books of physics today? Every one of us will have a different answer. Some will say it is the structure of the elementary particles. Others ask in what form is the mass or the attraction that has held the universe together thus far against perpetual expansion. Others will think of the November 11, 1999 dedication of America's first 6 kilometer by 6 kilometer gravity wave detector and will ask what information it will bring us about events going on in the deep and secret places of the universe. My own hope is that we'll see in time to come the answer to a question now almost a century old, "How come the quantum?" Gregory Breit would have sympathized with the investigations at each of these fronts, and could surely have filled us in on what the pioneers thought and said about the question, "How come the quantum?" ...

  10. Nigeria Anopheles Vector Database: An Overview of 100 Years' Research

    PubMed Central

    Okorie, Patricia Nkem; McKenzie, F. Ellis; Ademowo, Olusegun George; Bockarie, Moses; Kelly-Hope, Louise

    2011-01-01

    Anopheles mosquitoes are important vectors of malaria and lymphatic filariasis (LF), which are major public health diseases in Nigeria. Malaria is caused by infection with a protozoan parasite of the genus Plasmodium and LF by the parasitic worm Wuchereria bancrofti. Updating our knowledge of the Anopheles species is vital in planning and implementing evidence based vector control programs. To present a comprehensive report on the spatial distribution and composition of these vectors, all published data available were collated into a database. Details recorded for each source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, morphological and molecular species identification methods, insecticide resistance status, including evidence of the kdr allele, and P. falciparum sporozoite rate and W. bancrofti microfilaria prevalence. This collation resulted in a total of 110 publications, encompassing 484,747 Anopheles mosquitoes in 632 spatially unique descriptions at 142 georeferenced locations being identified across Nigeria from 1900 to 2010. Overall, the highest number of vector species reported included An. gambiae complex (65.2%), An. funestus complex (17.3%), An. gambiae s.s. (6.5%). An. arabiensis (5.0%) and An. funestus s.s. (2.5%), with the molecular forms An. gambiae M and S identified at 120 locations. A variety of sampling/collection and species identification methods were used with an increase in molecular techniques in recent decades. Insecticide resistance to pyrethroids and organochlorines was found in the main Anopheles species across 45 locations. Presence of P. falciparum and W. bancrofti varied between species with the highest sporozoite rates found in An. gambiae s.s, An. funestus s.s. and An. moucheti, and the highest microfilaria prevalence in An. gambiae s.l., An. arabiensis, and An. gambiae s.s. This comprehensive geo-referenced database provides an essential baseline on Anopheles

  11. Global change and water resources in the next 100 years

    NASA Astrophysics Data System (ADS)

    Larsen, M. C.; Hirsch, R. M.

    2010-03-01

    We are in the midst of a continental-scale, multi-year experiment in the United States, in which we have not defined our testable hypotheses or set the duration and scope of the experiment, which poses major water-resources challenges for the 21st century. What are we doing? We are expanding population at three times the national growth rate in our most water-scarce region, the southwestern United States, where water stress is already great and modeling predicts decreased streamflow by the middle of this century. We are expanding irrigated agriculture from the west into the east, particularly to the southeastern states, where increased competition for ground and surface water has urban, agricultural, and environmental interests at odds, and increasingly, in court. We are expanding our consumption of pharmaceutical and personal care products to historic high levels and disposing them in surface and groundwater, through sewage treatment plants and individual septic systems. These substances are now detectable at very low concentrations and we have documented significant effects on aquatic species, particularly on fish reproduction function. We don’t yet know what effects on human health may emerge, nor do we know if we need to make large investments in water treatment systems, which were not designed to remove these substances. These are a few examples of our national-scale experiment. In addition to these water resources challenges, over which we have some control, climate change models indicate that precipitation and streamflow patterns will change in coming decades, with western mid-latitude North America generally drier. We have already documented trends in more rain and less snow in western mountains. This has large implications for water supply and storage, and groundwater recharge. We have documented earlier snowmelt peak spring runoff in northeastern and northwestern States, and western montane regions. Peak runoff is now about two weeks earlier than it was

  12. Adaptive dynamic programming for finite-horizon optimal control of discrete-time nonlinear systems with ε-error bound.

    PubMed

    Wang, Fei-Yue; Jin, Ning; Liu, Derong; Wei, Qinglai

    2011-01-01

    In this paper, we study the finite-horizon optimal control problem for discrete-time nonlinear systems using the adaptive dynamic programming (ADP) approach. The idea is to use an iterative ADP algorithm to obtain the optimal control law which makes the performance index function close to the greatest lower bound of all performance indices within an ε-error bound. The optimal number of control steps can also be obtained by the proposed ADP algorithms. A convergence analysis of the proposed ADP algorithms in terms of performance index function and control policy is made. In order to facilitate the implementation of the iterative ADP algorithms, neural networks are used for approximating the performance index function, computing the optimal control policy, and modeling the nonlinear system. Finally, two simulation examples are employed to illustrate the applicability of the proposed method. PMID:20876014

  13. Neural network-based finite-horizon optimal control of uncertain affine nonlinear discrete-time systems.

    PubMed

    Zhao, Qiming; Xu, Hao; Jagannathan, Sarangapani

    2015-03-01

    In this paper, the finite-horizon optimal control design for nonlinear discrete-time systems in affine form is presented. In contrast with the traditional approximate dynamic programming methodology, which requires at least partial knowledge of the system dynamics, in this paper, the complete system dynamics are relaxed utilizing a neural network (NN)-based identifier to learn the control coefficient matrix. The identifier is then used together with the actor-critic-based scheme to learn the time-varying solution, referred to as the value function, of the Hamilton-Jacobi-Bellman (HJB) equation in an online and forward-in-time manner. Since the solution of HJB is time-varying, NNs with constant weights and time-varying activation functions are considered. To properly satisfy the terminal constraint, an additional error term is incorporated in the novel update law such that the terminal constraint error is also minimized over time. Policy and/or value iterations are not needed and the NN weights are updated once a sampling instant. The uniform ultimate boundedness of the closed-loop system is verified by standard Lyapunov stability theory under nonautonomous analysis. Numerical examples are provided to illustrate the effectiveness of the proposed method. PMID:25720005

  14. Morphological response of songbirds to 100 years of landscape change in North America.

    PubMed

    Desrochers, A

    2010-06-01

    Major landscape changes caused by humans may create strong selection pressures and induce rapid evolution in natural populations. In the last 100 years, eastern North America has experienced extensive clear-cutting in boreal areas, while afforestation has occurred in most temperate areas. Based on museum specimens, I show that wings of several boreal forest songbirds and temperate songbirds of non-forest habitats have become more pointed over the last 100 years. In contrast, wings of most temperate forest and early-successional boreal forests species have become less pointed over the same period. In contrast to wing shape, the bill length of most species did not change significantly through time. These results are consistent with the "habitat isolation hypothesis", i.e., songbirds evolved in response to recent changes in the amount of available habitat and associated implications for mobility. Rapid morphological evolution may mitigate, without necessarily preventing, negative consequences of habitat loss caused by humans through direct exploitation or climate change. PMID:20583699

  15. Time horizons and substance use among African American youths living in disadvantaged urban areas.

    PubMed

    Cheong, JeeWon; Tucker, Jalie A; Simpson, Cathy A; Chandler, Susan D

    2014-04-01

    Transitioning from adolescence to full-fledged adulthood is often challenging, and young people who live in disadvantaged urban neighborhoods face additional obstacles and experience disproportionately higher negative outcomes, including substance abuse and related risk behaviors. This study investigated whether substance use among African Americans ages 15 to 25 (M=18.86 years) living in such areas was related to present-dominated time perspectives and higher delay discounting. Participants (N=344, 110 males, 234 females) living in Deep South disadvantaged urban neighborhoods were recruited using Respondent Driven Sampling, an improved peer-referral sampling method suitable for accessing this hard-to-reach target group. Structured field interviews assessed alcohol, tobacco, and illicit drug use and risk/protective factors, including time perspectives (Zimbardo Time Perspective Inventory [ZTPI]) and behavioral impulsivity (delay discounting task). As predicted, substance use was positively related to a greater ZTPI orientation toward present pleasure and a lower tendency to plan and achieve future goals. Although the sample as a whole showed high discounting of delayed rewards, discount rates did not predict substance use. The findings suggest that interventions to lengthen time perspectives and promote enriched views of future possible selves may prevent and reduce substance use among disadvantaged youths. Discontinuities among the discounting and time perspective variables in relation to substance use merit further investigation. PMID:24531637

  16. Impact of curvature divergences on physical observers in a wormhole space-time with horizons

    NASA Astrophysics Data System (ADS)

    Olmo, Gonzalo J.; Rubiera-Garcia, D.; Sanchez-Puente, A.

    2016-06-01

    The impact of curvature divergences on physical observers in a black hole space-time, which, nonetheless, is geodesically complete is investigated. This space-time is an exact solution of certain extensions of general relativity coupled to Maxwell’s electrodynamics and, roughly speaking, consists of two Reissner-Nordström (or Schwarzschild or Minkowski) geometries connected by a spherical wormhole near the center. We find that, despite the existence of infinite tidal forces, causal contact is never lost among the elements making up the observer. This suggests that curvature divergences may not be as pathological as traditionally thought.

  17. 1.3 mm WAVELENGTH VLBI OF SAGITTARIUS A*: DETECTION OF TIME-VARIABLE EMISSION ON EVENT HORIZON SCALES

    SciTech Connect

    Fish, Vincent L.; Doeleman, Sheperd S.; Beaudoin, Christopher; Bolin, David E.; Rogers, Alan E. E.; Blundell, Ray; Gurwell, Mark A.; Moran, James M.; Primiani, Rurik; Bower, Geoffrey C.; Plambeck, Richard; Chamberlin, Richard; Freund, Robert; Friberg, Per; Honma, Mareki; Oyama, Tomoaki; Inoue, Makoto; Krichbaum, Thomas P.; Lamb, James; Marrone, Daniel P.

    2011-02-01

    Sagittarius A*, the {approx}4 x 10{sup 6} M{sub sun} black hole candidate at the Galactic center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength very long baseline interferometry (VLBI). We report on 1.3 mm wavelength observations of Sgr A* using a VLBI array consisting of the JCMT on Mauna Kea, the Arizona Radio Observatory's Submillimeter Telescope on Mt. Graham in Arizona, and two telescopes of the CARMA array at Cedar Flat in California. Both Sgr A* and the quasar calibrator 1924-292 were observed over three consecutive nights, and both sources were clearly detected on all baselines. For the first time, we are able to extract 1.3 mm VLBI interferometer phase information on Sgr A* through measurement of closure phase on the triangle of baselines. On the third night of observing, the correlated flux density of Sgr A* on all VLBI baselines increased relative to the first two nights, providing strong evidence for time-variable change on scales of a few Schwarzschild radii. These results suggest that future VLBI observations with greater sensitivity and additional baselines will play a valuable role in determining the structure of emission near the event horizon of Sgr A*.

  18. Killing Horizons Kill Horizon Degrees

    NASA Astrophysics Data System (ADS)

    Bergamin, L.; Grumiller, D.

    Frequently, it is argued that the microstates responsible for the Bekenstein-Hawking entropy should arise from some physical degrees of freedom located near or on the black hole horizon. In this essay, we elucidate that instead entropy may emerge from the conversion of physical degrees of freedom, attached to a generic boundary, into unobservable gauge degrees of freedom attached to the horizon. By constructing the reduced phase space, it can be demonstrated that such a transmutation indeed takes place for a large class of black holes, including Schwarzschild.

  19. The Glacier Peak Tephra: A Continental-Scale Latest Pleistocene Time Horizon

    NASA Astrophysics Data System (ADS)

    Pyne-O'Donnell, S.; Cwynar, L. C.; Vincent, J. H.; Spear, R.; Froese, D. G.

    2014-12-01

    The latest Pleistocene eruptions of Glacier Peak in the Cascade Range deposited a widespread set of tephras throughout much of western North America within a short time span where they serve as valuable marker layers for inter-site correlation and chronostratigraphical control. We report the detection of these tephras in microscopic form in three lakes along the Eastern Seaboard (Maine and Nova Scotia). These distinct distal lake layers occur as closely spaced couplets which retain the subtle geochemical variation that characterises the proximal Glacier Peak G and B layers. New radiocarbon dates for the tephras also closely corroborate the most recently revised proximal dates for the tephras (ca. 13,700 - 13,400 cal. yr B.P) which found that they are ca. 400 14C yr older than hitherto thought. Their presence this far eastward implies that their deposition spans the intervening continent (>4000 km) and adds to a developing distal tephrostratigraphical framework with applications to studies of latest Pleistocene deglaciation and environmental change, megafaunal extinction and archaeology.

  20. 100+ years of instrumental seismology: the example of the ISC-GEM Global Earthquake Instrumental Catalogue

    NASA Astrophysics Data System (ADS)

    Storchak, Dmitry; Di Giacomo, Domenico

    2015-04-01

    Systematic seismological observations of earthquakes using seismic instruments on a global scale began more than 100 years ago. Since then seismologists made many discoveries about the Earth interior and the physics of the earthquakes, also thanks to major developments in the seismic instrumentation deployed around the world. Besides, since the establishment of the first global networks (Milne and Jesuit networks), seismologists around the world stored and exchanged the results of routine observations (e.g., picking of arrival times, amplitude-period measurements, etc.) or more sophisticated analyses (e.g., moment tensor inversion) in seismological bulletins/catalogues. With a project funded by the GEM Foundation (www.globalquakemodel.org), the ISC and the Team of International Experts released a new global earthquake catalogue, the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php), which, differently from previous global seismic catalogues, has the unique feature of covering the entire period of instrumental seismology with locations and magnitude re-assessed using modern approaches for the global earthquakes selected for processing (in the current version approximately 21,000). During the 110 years covered by the ISC-GEM catalogue many seismological developments occurred in terms of instrumentation, seismological practice and knowledge of the physics of the earthquakes. In this contribution we give a brief overview of the major milestones characterizing the last 100+ years of instrumental seismology that were relevant for the production of the ISC-GEM catalogue and the major challenges we faced to obtain a catalogue as homogenous as possible.

  1. HORIZON SENSING (PROPOSAL NO.51)

    SciTech Connect

    Larry G. Stolarczyk

    2003-07-01

    Real-time horizon sensing on continuous mining machines is becoming an industry tool. Installation and testing of production-grade Horizon Sensor (HS) systems continued this quarter at Monterey Coal Company (ExxonMobil), Mountain Coal Company West Elk Mine (Arch), and Ohio Valley Coal Company (OVC). Monitoring of system function, user experience, and mining benefits is ongoing. All horizon sensor components have finished MSHA (U.S.) and IEC (International) certification.

  2. HORIZON SENSING (PROPOSAL NO.51)

    SciTech Connect

    Larry G. Stolarczyk

    2003-07-30

    Real-time horizon sensing on continuous mining (CM) machines is becoming an industry tool. Installation and testing of production-grade Horizon Sensor (HS) systems has been ongoing this quarter at Monterey Coal Company (ExxonMobil), Mountain Coal Company West Elk Mine (Arch), Deserado Mining Company (Blue Mountain Energy), and The Ohio Valley Coal Company (TOVCC). Monitoring of system function, user experience, and mining benefits is ongoing. All horizon sensor components have finished MSHA (U.S.) and IEC (International) certification.

  3. The optimal manufacturing batch size with rework under time-varying demand process for a finite time horizon

    NASA Astrophysics Data System (ADS)

    Musa, Sarah; Supadi, Siti Suzlin; Omar, Mohd

    2014-07-01

    Rework is one of the solutions to some of the main issues in reverse logistic and green supply chain as it reduces production cost and environmental problem. Many researchers focus on developing rework model, but to the knowledge of the author, none of them has developed a model for time-varying demand rate. In this paper, we extend previous works and develop multiple batch production system for time-varying demand rate with rework. In this model, the rework is done within the same production cycle.

  4. Planning ahead in public health? A qualitative study of the time horizons used in public health decision-making

    PubMed Central

    Taylor-Robinson, David C; Milton, Beth; Lloyd-Williams, Ffion; O'Flaherty, Martin; Capewell, Simon

    2008-01-01

    Background In order to better understand factors that influence decisions for public health, we undertook a qualitative study to explore issues relating to the time horizons used in decision-making. Methods Qualitative study using semi-structured interviews. 33 individuals involved in the decision making process around coronary heart disease were purposively sampled from the UK National Health Service (national, regional and local levels), academia and voluntary organizations. Analysis was based on the framework method using N-VIVO software. Interviews were transcribed, coded and emergent themes identified. Results Many participants suggested that the timescales for public health decision-making are too short. Commissioners and some practitioners working at the national level particularly felt constrained in terms of planning for the long-term. Furthermore respondents felt that longer term planning was needed to address the wider determinants of health and to achieve societal level changes. Three prominent 'systems' issues were identified as important drivers of short term thinking: the need to demonstrate impact within the 4 year political cycle; the requirement to 'balance the books' within the annual commissioning cycle and the disruption caused by frequent re-organisations within the health service. In addition respondents suggested that the tools and evidence base for longer term planning were not well established. Conclusion Many public health decision and policy makers feel that the timescales for decision-making are too short. Substantial systemic barriers to longer-term planning exist. Policy makers need to look beyond short-term targets and budget cycles to secure investment for long-term improvement in public health. PMID:19094194

  5. A Time-Series of Surface Oil Distribution Detected by Satellite SAR During the Deepwater Horizon Blowout

    NASA Astrophysics Data System (ADS)

    MacDonald, I. R.; Garcia-Pineda, O. G.; Solow, A.; Daneshgar, S.; Beet, A.

    2013-12-01

    Oil discharged as a result of the Deepwater Horizon disaster was detected on the surface of the Gulf of Mexico by synthetic aperture radar satellites from 25 April 2010 until 4 August 2010. SAR images were not restricted by daylight or cloud-cover. Distribution of this material is a tracer for potential environmental impacts and an indicator of impact mitigation due to response efforts and physical forcing factors. We used a texture classifying neural network algorithm for semi-supervised processing of 176 SAR images from the ENVISAT, RADARSAT I, and COSMO-SKYMED satellites. This yielded an estimate the proportion of oil-covered water within the region sampled by each image with a nominal resolution of 10,000 sq m (100m pixels), which was compiled as a 5-km equal area grid covering the northern Gulf of Mexico. Few images covered the entire impact area, so analysis was required to compile a regular time-series of the oil cover. A Gaussian kernel using a bandwidth of 2 d was used to estimate oil cover percent in each grid at noon and midnight throughout the interval. Variance and confidence intervals were calculated for each grid and for the global 12-h totals. Results animated across the impact region show the spread of oil under the influence of physical factors. Oil cover reached an early peak of 17032.26 sq km (sd 460.077) on 18 May, decreasing to 27% of this total on 4 June, following by sharp increase to an overall maximum of 18424.56 sq km (sd 424.726) on 19 June. There was a significant negative correlation between average wind stress and the total area of oil cover throughout the time-series. Correlation between response efforts including aerial and subsurface application of dispersants and burning of gathered oil was negative, positive, or indeterminate at different time segments during the event. Daily totals for oil-covered surface waters of the Gulf of Mexico during 25 April - 9 August 2010 with upper and lower 0.95 confidence limits on estimate. (No oil

  6. From Smallpox to Big Data: The Next 100 Years of Epidemiologic Methods.

    PubMed

    Gange, Stephen J; Golub, Elizabeth T

    2016-03-01

    For more than a century, epidemiology has seen major shifts in both focus and methodology. Taking into consideration the explosion of "big data," the advent of more sophisticated data collection and analytical tools, and the increased interest in evidence-based solutions, we present a framework that summarizes 3 fundamental domains of epidemiologic methods that are relevant for the understanding of both historical contributions and future directions in public health. First, the manner in which populations and their follow-up are defined is expanding, with greater interest in online populations whose definition does not fit the usual classification by person, place, and time. Second, traditional data collection methods, such as population-based surveillance and individual interviews, have been supplemented with advances in measurement. From biomarkers to mobile health, innovations in the measurement of exposures and diseases enable refined accuracy of data collection. Lastly, the comparison of populations is at the heart of epidemiologic methodology. Risk factor epidemiology, prediction methods, and causal inference strategies are areas in which the field is continuing to make significant contributions to public health. The framework presented herein articulates the multifaceted ways in which epidemiologic methods make such contributions and can continue to do so as we embark upon the next 100 years. PMID:26443419

  7. Psychologists in medical schools and academic medical centers: over 100 years of growth, influence, and partnership.

    PubMed

    Robiner, William N; Dixon, Kim E; Miner, Jacob L; Hong, Barry A

    2014-04-01

    Psychologists have served on the faculties of medical schools for over 100 years. Psychologists serve in a number of different roles and make substantive contributions to medical schools' tripartite mission of research, education, and clinical service. This article provides an overview of the history of psychologists' involvement in medical schools, including their growing presence in and integration with diverse departments over time. We also report findings from a survey of medical school psychologists that explored their efforts in nonclinical areas (i.e., research, education, administration) as well as clinical endeavors (i.e., assessment, psychotherapy, consultation). As understanding of the linkage between behavioral and psychological factors and health status and treatment outcomes increases, the roles of psychologists in health care are likely to expand beyond mental health. An increasing focus on accountability-related to treatment outcomes and interprofessional research, education, and models of care delivery-will likely provide additional opportunities for psychologists within health care and professional education. The well-established alignment of psychologists' expertise and skills with the mission and complex organizational needs of medical schools augurs a partnership on course to grow stronger. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24588315

  8. Potential Hazards of Tsunami Waves along the Chinese coast in the next 100 years

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Yuen, D. A.; Sevre, E. O.; Shi, Y.

    2007-12-01

    In the next 100 years the Chinese coast faces potentially non-negligible danger from tsunamogenic earthquakes originating at the neighboring subducting plate boundaries in the Phillipines and the Ryukyu Islands. There are significant differences in the bottom bathymetry between the South China Sea bordering the southern province of Guangdong and the East China Sea and Yellow Sea adjacent to the provinces of Zhejiang, Jiangsu, and Shandong. We have found that the linear shallow-water equations can be used to predict with good enough accuracy the travel time of tsunami waves in the South China Sea, but the nonlinear shallow-water equations must be used for the shallower seas next to the northern Chinese provinces. There are some differences in the travel time predictions between the linear and nonlinear theories for the Yellow Sea region. This difference is enough to make a difference in terms of warning. We will use our newly developed probability method, called the probabilistic forecast of tsunami hazards ( PFTH ) for predicting the danger of tsunami waves with a certain height of around 2 meters to impinge on the cities along the Chinese coast in the next century.We have used the Gutenberg-Richter relationship applied locally to each locale for evaluating the probability of the seismic risk for large earthquakes, greater than magnitude 7. We have only included the frequency of shallow large earthquakes to take place . For the southern cities of Hong Kong and Macau, we found that the probability of a 2 meter wave to hit these ports is around 10 % in the next century. Cities in Taiwan are less vulnerable than the large coastal cities on the Chinese mainland. The probability results for the northern cities of Shanghai and Qingdao are around a few per cent for smaller wave heights like one meter or so. But even these smaller waves can be damaging --

  9. Discharge, gage height, and elevation of 100-year floods in the Hudson River basin, New York

    USGS Publications Warehouse

    Archer, Roger J.

    1978-01-01

    The flood discharge that may be expected to be equaled or exceeded on the average of once in 100 years (100-year flood) was computed by the log-Pearson Type-III frequency relation for 72 stations in the Hudson River basin. These discharges and, where available, their corresponding gage height and elevation above mean sea level are presented in tabular form. A short explanation of computation methods is included. The data are to be used as part of a federally funded study of the water resources and related land resources of the Hudson River basin. (Woodard-USGS)

  10. The Archives of the Department of Terrestrial Magnetism: Documenting 100 Years of Carnegie Science

    NASA Astrophysics Data System (ADS)

    Hardy, S. J.

    2005-12-01

    The archives of the Department of Terrestrial Magnetism (DTM) of the Carnegie Institution of Washington document more than a century of geophysical and astronomical investigations. Primary source materials available for historical research include field and laboratory notebooks, equipment designs, plans for observatories and research vessels, scientists' correspondence, and thousands of expedition and instrument photographs. Yet despite its history, DTM long lacked a systematic approach to managing its documentary heritage. A preliminary records survey conducted in 2001 identified more than 1,000 linear feet of historically-valuable records languishing in dusty, poorly-accessible storerooms. Intellectual control at that time was minimal. With support from the National Historical Publications and Records Commission, the "Carnegie Legacy Project" was initiated in 2003 to preserve, organize, and facilitate access to DTM's archival records, as well as those of the Carnegie Institution's administrative headquarters and Geophysical Laboratory. Professional archivists were hired to process the 100-year backlog of records. Policies and procedures were established to ensure that all work conformed to national archival standards. Records were appraised, organized, and rehoused in acid-free containers, and finding aids were created for the project web site. Standardized descriptions of each collection were contributed to the WorldCat bibliographic database and the AIP International Catalog of Sources for History of Physics. Historic photographs and documents were digitized for online exhibitions to raise awareness of the archives among researchers and the general public. The success of the Legacy Project depended on collaboration between archivists, librarians, historians, data specialists, and scientists. This presentation will discuss key aspects (funding, staffing, preservation, access, outreach) of the Legacy Project and is aimed at personnel in observatories, research

  11. 100 years of California’s water rights system: patterns, trends and uncertainty

    NASA Astrophysics Data System (ADS)

    Grantham, Theodore E.; Viers, Joshua H.

    2014-08-01

    For 100 years, California’s State Water Resources Control Board and its predecessors have been responsible for allocating available water supplies to beneficial uses, but inaccurate and incomplete accounting of water rights has made the state ill-equipped to satisfy growing societal demands for water supply reliability and healthy ecosystems. Here, we present the first comprehensive evaluation of appropriative water rights to identify where, and to what extent, water has been dedicated to human uses relative to natural supplies. The results show that water right allocations total 400 billion cubic meters, approximately five times the state’s mean annual runoff. In the state’s major river basins, water rights account for up to 1000% of natural surface water supplies, with the greatest degree of appropriation observed in tributaries to the Sacramento and San Joaquin Rivers and in coastal streams in southern California. Comparisons with water supplies and estimates of actual use indicate substantial uncertainty in how water rights are exercised. In arid regions such as California, over-allocation of surface water coupled with trends of decreasing supply suggest that new water demands will be met by re-allocation from existing uses. Without improvements to the water rights system, growing human and environmental demands portend an intensification of regional water scarcity and social conflict. California’s legal framework for managing its water resources is largely compatible with needed reforms, but additional public investment is required to enhance the capacity of the state’s water management institutions to effectively track and regulate water rights.

  12. Innovation and Involvement: 100 Years of Community Work with Older People.

    ERIC Educational Resources Information Center

    Glasby, Jon

    2000-01-01

    Birmingham Settlement has provided services to British older adults for over 100 years, including such innovations as adult day centers, meals on wheels, and transportation services. The participation of the clientele in research helped flesh out the history of the settlement through narratives that demonstrate its impact on the life of the…

  13. 100 Years of Cotton Production, Harvesting and Ginning Systems Engineering: 1907 - 2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The American Society of Agricultural and Biological Engineers (ASABE) celebrated its centennial year during 2007. As part of the ASABE centennial, the authors were asked to describe agricultural engineering accomplishments in U.S. cotton production, harvesting and ginning over the past 100 years. ...

  14. What Would You Look Like If You Were 100 Years Old?

    ERIC Educational Resources Information Center

    Petersen, Hugh

    1998-01-01

    Describes a project inspired by the 100th day of school in which first-grade students created a self-portrait of themselves at 100 years old and wrote an accompanying essay. States that the students drew wrinkles on the faces, age-appropriate clothing, gray or white hair, and even glasses as a finishing touch. (CMK)

  15. Refraction near the horizon

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Liller, William

    1990-01-01

    Variations in astronomical refraction near the horizon are examined. Sunset timings, a sextant mounted on a tripod, and a temperature profile are utilized to derive the variations in refraction data, collected from 7 locations. It is determined that the refraction ranges from 0.234 to 1.678 deg with an rms deviation of 0.16, and it is observed that the variation is larger than previously supposed. Some applications for the variation of refraction value are discussed.

  16. Areas subject to inundation by the 100-year flood in Avra Valley, Pima County, Arizona

    USGS Publications Warehouse

    Roeske, R.H.

    1978-01-01

    Avra Valley in Pima County, Arizona, is sparsely populated and is used mainly for agriculture and cattle grazing; however, its proximity to Tucson makes it desirable for urban development. Administrators and planners concerned with future land development may use the map report to determine the approximate areas that are subject to inundation by the 100-year flood. Avra Valley is drained mainly by Brawley Wash; Blanco Wash drains the west side of the valley. Most of the natural drainage system consists of small braided channels bordered by narrow bands of dense vegetation, which cause floodwater to spread over wide areas of shallow depths. During the 100-year flood, the areas inundated by Brawley and Blanco Washes may join in several places. (Woodard-USGS)

  17. HORIZON SENSING (PROPOSAL No.51)

    SciTech Connect

    Larry G. Stolarczyk, Sc.D.

    2002-04-30

    Real-time horizon sensing on continuous mining machines is becoming an industry tool. Installation and testing of production-grade HS systems has been ongoing this quarter at Monterey Coal Company (EXXON), FMC Trona, Twentymile Coal Company (RAG America), and SASOL Coal. Detailed monitoring of system function, user experience, and mining benefits is ongoing. All horizon sensor components have finished MSHA (U.S.) and IEC (International) certification.

  18. Creating Long Term Income Streams for the 100 Year Starship Study Initiative

    NASA Astrophysics Data System (ADS)

    Sylvester, A. J.

    Development and execution of long term research projects are very dependent on a consistent application of funding to maximize the potential for success. The business structure for the 100 Year Starship Study project should allow for multiple income streams to cover the expenses of the research objectives. The following examples illustrate the range of potential avenues: 1) affiliation with a charitable foundation for creating a donation program to fund a long term endowment for research, 2) application for grants to fund initial research projects and establish the core expertise of the research entity, 3) development of intellectual property which can then be licensed for additional revenue, 4) creation of spinout companies with equity positions retained by the lab for funding the endowment, and 5) funded research which is dual use for the technology goals of the interstellar flight research objectives. With the establishment of a diversified stream of funding options, then the endowment can be funded at a level to permit dedicated research on the interstellar flight topics. This paper will focus on the strategy of creating spinout companies to create income streams which would fund the endowment of the 100 Year Starship Study effort. This technique is widely used by universities seeking to commercially develop and market technologies developed by university researchers. An approach will be outlined for applying this technique to potentially marketable technologies generated as a part of the 100 Year Starship Study effort.

  19. Modeling the Emergent Impacts of Harvesting Acadian Forests over 100+ Years

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Plug, L. J.

    2007-12-01

    Harvesting strategies and policies for Acadian forest in Nova Scotia, Canada, presently are set using Decision Support Models (DSMs) that aim to maximize the long-term (>100y) value of forests through decisions implemented over short time horizons (5-80 years). However, DSMs typically are aspatial, lack ecological processes and do not treat erosion, so the long-term (>100y) emergent impacts of the prescribed forestry decisions on erosion and vegetation in Acadian forests remain poorly known. To better understand these impacts, we created an equation-based model that simulates the evolution of a ≥4 km2 forest in time steps of 1 y and at a spatial resolution of 3 m2, the footprint of a single mature tree. The model combines 1) ecological processes of recruitment, competition, and mortality; 2) geomorphic processes of hillslope erosion; 3) anthropic processes of tree harvesting, replanting, and road construction under constraints imposed by regulations and cost/benefit ratio. The model uses digital elevation models, parameters (where available), and calibration (where measurements are not available) for conditions presently found in central Cape Breton, Nova Scotia. The model is unique because it 1) deals with the impacts of harvesting on an Acadian forest; and 2) vegetation and erosion are coupled. The model was tested by comparing the species-specific biomass of long-term (40 y) forest plot data to simulated results. At the spatial scale of individual 1 ha plots, model predictions presently account for approximately 50% of observed biomass changes through time, but predictions are hampered by the effects of serendipitous "random" events such as single tree windfall. Harvesting increases the cumulative erosion over 3000 years by 240% when compared to an old growth forest and significantly suppresses the growth of Balsam Fir and Sugar Maple. We discuss further tests of the model, and how it might be used to investigate the long-term sustainability of the

  20. Spatio-temporal analysis of rainfall trends over a maritime state (Kerala) of India during the last 100 years

    NASA Astrophysics Data System (ADS)

    Nair, Archana; Ajith Joseph, K.; Nair, K. S.

    2014-05-01

    Kerala, a maritime state of India is bestowed with abundant rainfall which is about three times the national average. This study is conducted to have a better understanding of rainfall variability and trend at regional level for this state during the last 100 years. It is found that the rainfall variation in northern and southern regions of Kerala is large and the deviation is on different timescales. There is a shifting of rainfall mean and variability during the seasons. The trend analysis on rainfall data over the last 100 years reveals that there is a significant (99%) decreasing trend in most of the regions of Kerala especially in the month of January, July and November. The annual and seasonal trends of rainfall in most regions of Kerala are also found to be decreasing significantly. This decreasing trend may be related to global anomalies as a result of anthropogenic green house gas (GHG) emissions due to increased fossil fuel use, land-use change due to urbanisation and deforestation, proliferation in transportation associated atmospheric pollutants. We have also conducted a study of the seasonality index (SI) and found that only one district in the northern region (Kasaragod) has seasonality index of more than 1 and that the distribution of monthly rainfall in this district is mostly attributed to 1 or 2 months. In rest of the districts, the rainfall is markedly seasonal. The trend in SI reveals that the rainfall distribution in these districts has become asymmetric with changes in rainfall distribution.

  1. South american geochronology: radiometric time scale for middle to late tertiary mammal-bearing horizons in patagonia.

    PubMed

    Marshall, L G; Pascual, R; Curtis, G H; Drake, R E

    1977-03-25

    Radiometric (potassium-argon) age determinations for basalts and tuffs associated with middle to late Tertiary mammal-bearing horizons in Patagonia, southern Argentina, permit refinement of boundaries and hiatuses between beds of Deseadan (early Oligocene) through Friasian (middle to late Miocene) age. At two localities beds of Deseadan age are overlain by basalts, which gave dates of 33.6 and 35.4 million years ago; 34.0 million years ago is tentatively accepted as a terminal date for known Deseadan. At several localities beds of Colhuehuapian age are underlain by basalts, which gave dates ranging from 28.8 to 24.3 million years ago; 25.0 million years is tentatively taken as a basal age for known Colhuehuapian. The paleontological hiatus between known Deseadan and known Colhuehuapian is thus in the order of 9.0 million years. Two tuffs from the Santa Cruz Formation (Santacrucian) gave ages of 21.7 and 18.5 million years. Plagioclase and biotite concentrates of an ignimbrite from the Collón Curá Formation (Friasian) gave ages ranging from 15.4 to 14.0 million years. PMID:17738414

  2. 100 years since the discovery of cosmic rays. A brief history

    NASA Astrophysics Data System (ADS)

    Chiavassa, Andrea

    2012-11-01

    With the words "Cosmic Rays" we mean particles impinging on the earth atmosphere. The existence of these particles was discovered in 1912, i.e. exactly 100 years ago, by the Austrian physicist Victor Hesss. In this contribution I will describe the steps that lead to such a discovery: from the electroscope measurements, showing their spontaneous discharge, to the correct explanation of this results with the existence of charged particles arriving from outside of the atmosphere. Then I will discuss the first steps of experimental particle physics, obtained with experiments performed detecting cosmic rays, that allowed important discoveries as the detection of antimatter and of new subatominc particles as muons and pions.

  3. Pluto's Atmosphere from the 2015 June 29 Ground-based Stellar Occultation at the Time of the New Horizons Flyby

    NASA Astrophysics Data System (ADS)

    Sicardy, B.; Talbot, J.; Meza, E.; Camargo, J. I. B.; Desmars, J.; Gault, D.; Herald, D.; Kerr, S.; Pavlov, H.; Braga-Ribas, F.; Assafin, M.; Benedetti-Rossi, G.; Dias-Oliveira, A.; Gomes-Júnior, A. R.; Vieira-Martins, R.; Bérard, D.; Kervella, P.; Lecacheux, J.; Lellouch, E.; Beisker, W.; Dunham, D.; Jelínek, M.; Duffard, R.; Ortiz, J. L.; Castro-Tirado, A. J.; Cunniffe, R.; Querel, R.; Yock, P. C.; Cole, A. A.; Giles, A. B.; Hill, K. M.; Beaulieu, J. P.; Harnisch, M.; Jansen, R.; Pennell, A.; Todd, S.; Allen, W. H.; Graham, P. B.; Loader, B.; McKay, G.; Milner, J.; Parker, S.; Barry, M. A.; Bradshaw, J.; Broughton, J.; Davis, L.; Devillepoix, H.; Drummond, J.; Field, L.; Forbes, M.; Giles, D.; Glassey, R.; Groom, R.; Hooper, D.; Horvat, R.; Hudson, G.; Idaczyk, R.; Jenke, D.; Lade, B.; Newman, J.; Nosworthy, P.; Purcell, P.; Skilton, P. F.; Streamer, M.; Unwin, M.; Watanabe, H.; White, G. L.; Watson, D.

    2016-03-01

    We present results from a multi-chord Pluto stellar occultation observed on 2015 June 29 from New Zealand and Australia. This occurred only two weeks before the NASA New Horizons flyby of the Pluto system and serves as a useful comparison between ground-based and space results. We find that Pluto's atmosphere is still expanding, with a significant pressure increase of 5 ± 2% since 2013 and a factor of almost three since 1988. This trend rules out, as of today, an atmospheric collapse associated with Pluto's recession from the Sun. A central flash, a rare occurrence, was observed from several sites in New Zealand. The flash shape and amplitude are compatible with a spherical and transparent atmospheric layer of roughly 3 km in thickness whose base lies at about 4 km above Pluto's surface, and where an average thermal gradient of about 5 K km-1 prevails. We discuss the possibility that small departures between the observed and modeled flash are caused by local topographic features (mountains) along Pluto's limb that block the stellar light. Finally, using two possible temperature profiles, and extrapolating our pressure profile from our deepest accessible level down to the surface, we obtain a possible range of 11.9-13.7 μbar for the surface pressure. Partly based on observations made with the ESO WFI camera at the 2.2 m Telescope (La Silla), under program ID 079.A-9202(A) within the agreement between the ON/MCTI and the Max Planck Society, with the ESO camera NACO at the Very Large Telescope (Paranal), under program ID 089.C-0314(C), and at the Pico dos Dias Observatory/LNA, Brazil.

  4. Solar wind variations in the 60-100 year period range: A review

    NASA Technical Reports Server (NTRS)

    Feynman, J.

    1983-01-01

    The evidence for and against the reality of a solar wind variation in the period range of 60-100 years is reexamined. Six data sets are reviewed; sunspot numbers, geomagnetic variations, two auroral data sets and two (14)C data sets. These data are proxies for several different aspects of the solar wind and the presence or absence of 60-100 year cyclic behavior in a particular data set does not necessarily imply the presence or absence of this variation in other sets. It was concluded that two different analyses of proxy data for a particular characteristic of the heliospheric solar wind yielded conflicting results. This conflict can be resolved only by future research. It is also definitely confirmed that proxy data for the solar wind in the ecliptic at 1 A.U. undergo a periodic variation with a period of approximately 87 years. The average amplitude and phase of this variation as seen in eleven cycles of proxy data are presented.

  5. Are Geodetically and Geologically Constrained Vertical Deformation Models Compatible With the 100-Year Coastal Tide Gauge Record in California?

    NASA Astrophysics Data System (ADS)

    Smith-Konter, B. R.; Sandwell, D. T.

    2006-12-01

    Sea level change has been continuously recorded along the California coastline at several tide gauge stations for the past 50-100 years. These stations provide a temporal record of sea level change, generally attributed to post-glacial rebound and ocean climate phenomena. However, geological processes, including displacements from large earthquakes, have also been shown to produce sea level variations. Furthermore, the vertical tectonic response to interseismic strain accumulation in regions of major fault bends has been shown to produce uplift and subsidence rates consistent with sea level trends. To investigate the long-term extent and implication of tectonic deformation on sea level change, we compare time series data from California tide gauge stations to model estimates of vertical displacements produced by earthquake cycle deformation. Using a 3-D semi-analytic viscoelastic model, we combine geologic slip rates, geodetic velocities, and historical seismic data to simulate both horizontal and vertical deformation of the San Andreas Fault System. Using this model, we generate a time-series of vertical displacements spanning the 100-year sea level record and compare this to tide gauge data provided by the Permanent Service for Mean Sea Level (PSMSL). Comparison between sea level data and a variety of geologically and geodetically constrained models confirms that the two are highly compatible. Vertical displacements are largely controlled by interseismic strain accumulation, however displacements from major earthquakes are also required to explain varying trends in the sea level data. Models based on elastic plate thicknesses of 30-50km and viscosities of 7x10^1^8-2x10^1^9 Pa-s produce vertical displacements at tide-gauge locations that explain long-term trends in the sea level record to a high degree of accuracy at nearly all stations. However, unmodeled phenomena are also present in the sea level data and require further inspection.

  6. Tree rings record 100 years of hydrologic change within a wetland

    USGS Publications Warehouse

    Yanosky, Thomas M.; Kappel, William M.

    1997-01-01

    Hydrology and tree growth were investigated within a small wetland in the Tully Valley of central New York, about 20 miles south of Syracuse. In late 1994 it was noted that some wetland trees were dying, and local residents reported that flow of a small stream draining the wetland seemingly increased and became more brackish since the mid to late 1980s. The wetland is about 3 miles north of an extensive salt mining operation known to have degraded local water quality, but no effects of mining had been confirmed previously near the wetland. The oldest wetland trees started to grow before the onset of mining in 1889, and thus tree-ring studies were undertaken not only to investi-gate recent hydrologic change within the wetland, but also to search for evidence of any other changes during the last 100 years.

  7. 100 Years of British military neurosurgery: on the shoulders of giants.

    PubMed

    Roberts, S A G

    2015-01-01

    Death from head injuries has been a feature of conflicts throughout the world for centuries. The burden of mortality has been variously affected by the evolution in weaponry from war-hammers to explosive ordnance, the influence of armour on survivability and the changing likelihood of infection as a complicating factor. Surgery evolved from haphazard trephination to valiant, yet disjointed, neurosurgery by a variety of great historical surgeons until the Crimean War of 1853-1856. However, it was events initiated by the Great War of 1914-1918 that not only marked the development of modern neurosurgical techniques, but our approach to military surgery as a whole. Here the author describes how 100 years of conflict and the input and intertwining relationships between the 20th century's great neurosurgeons established neurosurgery in the United Kingdom and beyond. PMID:26292388

  8. Sustainable Foods and Medicines Support Vitality, Sex and Longevity for a 100-Year Starship Expedition

    NASA Astrophysics Data System (ADS)

    Edwards, M. R.

    Extended space flight requires foods and medicines that sustain crew health and vitality. The health and therapeutic needs for the entire crew and their children for a 100-year space flight must be sustainable. The starship cannot depend on resupply or carry a large cargo of pharmaceuticals. Everything in the starship must be completely recyclable and reconstructable, including food, feed, textiles, building materials, pharmaceuticals, vaccines, and medicines. Smart microfarms will produce functional foods with superior nutrition and sensory attributes. These foods provide high-quality protein and nutralence (nutrient density), that avoids obesity, diabetes, and other Western diseases. The combination of functional foods, lifestyle actions, and medicines will support crew immunity, energy, vitality, sustained strong health, and longevity. Smart microfarms enable the production of fresh medicines in hours or days, eliminating the need for a large dispensary, which eliminates concern over drug shelf life. Smart microfarms are adaptable to the extreme growing area, resource, and environmental constraints associated with an extended starship expedition.

  9. 100-year DASCH Light Curves of Kepler Planet-Candidate Host Stars

    NASA Astrophysics Data System (ADS)

    Tang, Sumin; Sasselov, Dimitar; Grindlay, Jonathan; Los, Edward; Servillat, Mathieu

    2013-07-01

    We present 100 year light curves of Kepler planet-candidate host stars from the Digital Access to a Sky Century at Harvard (DASCH) project. 261 out of 997 host stars have at least 10 good measurements on DASCH scans of the Harvard plates. 109 of them have at least 100 good measurements, including 70% (73 out of 104) of all host stars with g <= 13 mag, and 44% (100 out of 228) of all host stars with g <= 14 mag. Our typical photometric uncertainty is ~0.1-0.15 mag. No variation is found at 3σ level for these host stars, including 21 confirmed or candidate hot Jupiter systems which might be expected to show enhanced flares from magnetic interactions between dwarf primaries and their close and relatively massive planet companions.

  10. 100 years of Pb deposition and transport in soils in Champaign, Illinois, U.S.A

    USGS Publications Warehouse

    Zhang, Y.

    2003-01-01

    In Illinois, atmospheric deposition is one major source of heavy metal inputs to agricultural land. The atmospheric Pb deposition and transport record in agricultural soils in Champaign, Illinois, was established by studying surface and subsurface soil samples collected during the past 100 years from the Morrow Plots on the campus of the University of Illinois at Urbana-Champaign. The Pb content in the soil samples was measured and the Ph deposition fluxes were calculated. The Pb content in surface soils increased sharply in the first half of the 20th century, and stayed invariant since. The maximum Pb flux from the atmosphere was estimated to be 27 (??14) ??g cm-2 yr-1 around 1940. The major pollution source for this increase probably was residential coal burning. It was estimated that in 50 yr, more than 50% of the Pb input had been lost from the surface soils.

  11. A profile of Frank Harrison: a pioneering Sheffield dentist from 100 years ago.

    PubMed

    Figures, K; Smith, C

    2012-10-01

    A review of the personal papers relating to Frank Harrison and held by the School of Clinical Dentistry in Sheffield reveal what a dedicated clinician he was and the significance of his achievements from over 100 years ago, both locally and nationally for his chosen profession and also for the people of Sheffield. In addition to being one of the first dentists in the world to experiment with X-rays in dentistry, and the first to write up his findings in a dental journal, he designed and patented dental instruments, wrote books, lectured on fine art (particularly Venetian and Florentine art), and gave lectures to the public in the hope that they would heed his message on the importance of maintaining good oral health. A search of national archives and library resources has added further information about his family and professional accomplishments. PMID:23099699

  12. The Reissner Canard: The first all-metal airplane 100 years ago

    NASA Astrophysics Data System (ADS)

    Krause, Egon

    2012-10-01

    In 1912 Professor Hans Reissner of the Technical University Aachen built a canard-type aeroplane, the world-wide first completely out of metal: although the Reissner Canard initiated a new technology with the Junkers J1 the first to follow in 1915 and 1000 more until now, little is known about the very first steps way back in Aachen. This paper tries to recapture some details of the developments 100 years ago with the aid of early publications and photographs and shed some light on the first wing fabricated out of a corrugated aluminum sheet mounted at the tail of the braced-steel-pipe fuselage to earn its airworthiness in Berlin Johannisthal in 1912.

  13. PREFACE: Spanish Relativity Meeting (ERE 2014): almost 100 years after Einstein's revolution

    NASA Astrophysics Data System (ADS)

    Cerdá-Durán, P.; Font, J. A.; Ibáñez, J. M.; Lledó, M. A.; Navarro-Salas, J.; Olmo, G. J.

    2015-04-01

    This volume presents the proceedings of the international scientific conference ''Spanish Relativity Meeting (ERE 2014): almost 100 years after Einstein's revolution''. The conference was devoted to discussing the current state-of-the-art of a wide variety of topics of research in the fields of Gravitation and General Relativity in the ''pre-centennial'' year of General Relativity. The name of the conference was chosen to highlight the importance of the upcoming one hundredth anniversary of Einstein's theory of General Relativity, officially established by the Internal Society on General Relativity and Gravitation in November 25th, 2015. In particular, the conference was organized along three main lines of present-day research and applications of the theory, namely, Relativistic Astrophysics, Mathematical Relativity, and the interface between Gravitation and Quantum Field Theory.

  14. 1,100 years after an earthquake: modification of the earthquake record by submergence, Puget Lowland, Washington State

    NASA Astrophysics Data System (ADS)

    Arcos, M. E.

    2011-12-01

    Crustal faults may pose a complicated story for earthquake reconstruction. In some cases, regional tectonic strain overprints the record of coseismic land-level changes. This study looks at the record of earthquakes at two sites in the Puget Lowland, Gorst and the Skokomish delta, and how post-earthquake submergence modified the paleoseismic records. The Puget Lowland is the slowly subsiding forearc basin of the northern Cascadia subduction zone. A series of active thrust faults cross this lowland. Several of these faults generated large (M7+) earthquakes, about 1,100 years ago and both field sites have submerged at least 1.5 m since that time. This submergence masked the geomorphic record of uplift in some areas, resulting in a misreading of the zone of earthquake deformation and potential misinterpretation of the underlying fault structure. Earthquakes ~1,100 years ago uplifted both field localities and altered river dynamics. At Gorst, a tsunami and debris flow accompanied uplift of at least 3 m by the Seattle fault. The increased sediment load resulted in braided stream formation for a period after the earthquake. At the Skokomish delta, differential uplift trapped the river on the eastern side of the delta for the last 1,100 years resulting in an asymmetric intertidal zone, 2-km wider on one side of the delta than the other. The delta slope or submergence may contribute to high rates of flooding on the Skokomish River. Preliminary results show the millennial scale rates of submergence vary with the southern Puget Lowland submerging at a faster rate than the northern Puget Lowland. This submergence complicates the reconstruction of past earthquakes and renders assessment of future hazards difficult for those areas that are based on uplifted marine platforms and other coastal earthquake signatures in several ways. 1) Post-earthquake submergence reduces the apparent uplift of marine terraces. 2) Submergence makes zones of earthquake deformation appear narrower. 3

  15. Gravitational Horizon(3)

    NASA Astrophysics Data System (ADS)

    Yang, Chao Yuan

    2012-05-01

    Anomalous decelerations of spacecraft Pioneer-10,11,etc could be interpreted as signal delay effect between speed of gravity and that of light as reflected in virtual scale, similar to covarying virtual scale effect in relative motion (http://arxiv.org/html/math-ph/0001019v5).A finite speed of gravity faster than light could be inferred (http://arXiv.org/html/physics/0001034v2). Measurements of gravitational variations by paraconical pendulum during a total solar eclipse infer the same(http://arXiv.org/html/physics/0001034v9). A finite Superluminal speed of gravity is the necessary condition to imply that there exists gravitational horizon (GH). Such "GH" of our Universe would stretch far beyond the cosmic event horizon of light. Dark energy may be owing to mutually interactive gravitational horizons of cousin universes. Sufficient condition for the conjecture is that the dark energy would be increasing with age of our Universe since accelerated expansion started about 5 Gyr ago, since more and more arrivals of "GH" of distant cousin universes would interact with "GH" of our Universe. The history of dark energy variations between then and now would be desirable(http://arXiv.org/html/physics/0001034). In "GH" conjecture, the neighborhood of cousin universes would be likely boundless in 4D-space-time without begining or end. The dark energy would keep all universes in continually accelerated expansion to eventual fragmentation. Fragments would crash and merge into bangs, big or small, to form another generation of cousin universes. These scenarios might offer a clue to what was before the big bang.

  16. Finite-Horizon Near-Optimal Output Feedback Neural Network Control of Quantized Nonlinear Discrete-Time Systems With Input Constraint.

    PubMed

    Xu, Hao; Zhao, Qiming; Jagannathan, Sarangapani

    2015-08-01

    The output feedback-based near-optimal regulation of uncertain and quantized nonlinear discrete-time systems in affine form with control constraint over finite horizon is addressed in this paper. First, the effect of input constraint is handled using a nonquadratic cost functional. Next, a neural network (NN)-based Luenberger observer is proposed to reconstruct both the system states and the control coefficient matrix so that a separate identifier is not needed. Then, approximate dynamic programming-based actor-critic framework is utilized to approximate the time-varying solution of the Hamilton-Jacobi-Bellman using NNs with constant weights and time-dependent activation functions. A new error term is defined and incorporated in the NN update law so that the terminal constraint error is also minimized over time. Finally, a novel dynamic quantizer for the control inputs with adaptive step size is designed to eliminate the quantization error overtime, thus overcoming the drawback of the traditional uniform quantizer. The proposed scheme functions in a forward-in-time manner without offline training phase. Lyapunov analysis is used to investigate the stability. Simulation results are given to show the effectiveness and feasibility of the proposed method. PMID:25794403

  17. Deepwater Horizon Situation Report #5

    SciTech Connect

    2010-06-10

    At approximately 11:00 pm EDT April 20, 2010 an explosion occurred aboard the Deepwater Horizon mobile offshore drilling unit (MODU) located 52 miles Southeast of Venice, LA and 130 miles southeast of New Orleans, LA. The MODU was drilling an exploratory well and was not producing oil at the time of the incident. The Deepwater Horizon MODU sank 1,500 feet northwest of the well site. Detailed information on response and recovery operations can be found at: http://www.deepwaterhorizonresponse.com/go/site/2931/

  18. Horizon Report: 2009 Economic Development Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Levine, A.; Scott, C.; Smith, R.; Stone, S.

    2009-01-01

    The New Media Consortium's Horizon Project is an ongoing research project that seeks to identify and describe emerging technologies likely to have a large impact in education and other industries around the world over a five-year time period. The chief products of the project are the "Horizon Reports", an annual series of publications that…

  19. Does time heal all wounds? Community attachment, natural resource employment, and health impacts in the wake of the BP Deepwater Horizon disaster.

    PubMed

    Cope, Michael R; Slack, Tim; Blanchard, Troy C; Lee, Matthew R

    2013-05-01

    On April 20, 2010, the BP-leased Deepwater Horizon (BP-DH) oil rig exploded, resulting in the largest marine oil spill in history. In this paper we utilize one-of-a-kind household survey data-the Louisiana Community Oil Spill Survey-to examine the impacts of the BP-DH disaster on the mental and physical health of spill affected residents in coastal Louisiana, with a special focus on the influence of community attachment and natural resource employment. We find that levels of both negative mental and physical health were significantly more pronounced at baseline compared to later time points. We show that greater community attachment is linked to lower levels of negative health impacts in the wake of the oil spill and that the disaster had a uniquely negative impact on households involved in the fishing industry. Further, we find evidence that the relationship between community attachment and mental health is more pronounced at later points in time, and that the negative health impacts on fishers have worsened over time. Implications for research and policy are discussed. PMID:23522000

  20. Flood risk management in the Thames Estuary looking ahead 100 years.

    PubMed

    Lavery, Sarah; Donovan, Bill

    2005-06-15

    The River Thames tidal defences have provided protection against the increasing threat of tidal flooding from the North Sea for more than 2000 years. The flood of 1953 was the catalyst for the construction of the current system of River Thames tidal defences, which includes the Thames Barrier, and has provided one of the best standards of flood defence in the UK for over 20 years. Substantial growth is planned through "Thames Gateway", a regeneration initiative of the United Kingdom government. These new developments will fundamentally change the developed footprint in the Thames Estuary flood-plain, and will be in place for at least the next 100 years. This presents a challenge of planning future defence against a background of uncertainty over climate and other environmental change, while ensuring that correct decisions are made concerning the nature and location of new building in the tidal flood-plain. Through its "Thames Estuary 2100" project, the Environment Agency is developing a long-term strategy for flood risk management in the estuary. Implementation of major construction works on the River Thames could commence from around 2015. Alternatively, it may be decided that minimum works are undertaken to provide security and major investment is delayed until uncertainties over climate change have abated. Whatever long-term option is chosen, this must be preceded by a period of collaboration with the Thames Gateway developments to ensure appropriate and sustainable flood defences are incorporated in new riverside construction. PMID:16191661

  1. [Nutrient dynamics over the past 100 years and its restoration baseline in Dianshan Lake].

    PubMed

    Li, Xiao-Ping; Chen, Xiao-Hua; Dong, Xu-Hui; Dong, Zhi; Sun, Dun-Ping

    2012-10-01

    The restoration of eutrophic lakes requires a good knowledge on the history and baseline of nutrients in the lakes. This work conducted an analysis on 210Pb/137Cs, water content, loss-on-ignition, sedimentary total phosphorus (TP), total nitrogen (TN), total organic carbon (TOC) and diatoms in the four sediment cores from Dianshan Lake (near Shanghai City). Good coherence in palaeoproxies between the cores indicates a relatively stable sedimentary environment. With increasing human impact, diatom communities shifted from oligo-trophic species Cyclotella bodanica, C. ocelata, Achnanthes minutissima, Cocconeis placentula var lineate, Cymbella sp. , Fragilaria pintata, F. brevistrata, F. construens var venter to recent eutrophic species including Cyclostephanos dubias, C. atomus, Stephanodiscus minitulus, S. hantzschi, Aulacoseria alpigena. The epilimnetic TP over the past 100 years reconstructed using an established diatom-TP transfer function matches well with the monitoring TP where exists. Based on the sedimentary nutrient characteristics and diatom-reconstructed nutrient dynamics, we proposed that the nutrient baseline for Dianshan Lake is 50-60 microg x L(-1), 500 mg x kg(-1) and 550 mg x kg(-1) for water TP concentration, sedimentary TP and TN, respectively. PMID:23233952

  2. Rainfall and drought in equatorial east Africa during the past 1,100 years.

    PubMed

    Verschuren, D; Laird, K R; Cumming, B F

    2000-01-27

    Knowledge of natural long-term rainfall variability is essential for water-resource and land-use management in sub-humid regions of the world. In tropical Africa, data relevant to determining this variability are scarce because of the lack of long instrumental climate records and the limited potential of standard high-resolution proxy records such as tree rings and ice cores. Here we present a decade-scale reconstruction of rainfall and drought in equatorial east Africa over the past 1,100 years, based on lake-level and salinity fluctuations of Lake Naivasha (Kenya) inferred from three different palaeolimnological proxies: sediment stratigraphy and the species compositions of fossil diatom and midge assemblages. Our data indicate that, over the past millennium, equatorial east Africa has alternated between contrasting climate conditions, with significantly drier climate than today during the 'Medieval Warm Period' (approximately AD 1000-1270) and a relatively wet climate during the 'Little Ice Age' (approximately AD 1270-1850) which was interrupted by three prolonged dry episodes. We also find strong chronological links between the reconstructed history of natural long-term rainfall variation and the pre-colonial cultural history of east Africa, highlighting the importance of a detailed knowledge of natural long-term rainfall fluctuations for sustainable socio-economic development. PMID:10667789

  3. Migration and health in Southern Africa: 100 years and still circulating

    PubMed Central

    Lurie, Mark N.; Williams, Brian G.

    2014-01-01

    Migration has deep historical roots in South and Southern Africa and to this day continues to be highly prevalent and a major factor shaping South African society and health. In this paper we examine the role of migration in the spread of two diseases nearly 100 years apart: tuberculosis following the discovery of gold in 1886 and HIV in the early 1990s. Both cases demonstrate the critical role played by human migration in the transmission and subsequent dissemination of these diseases to rural areas. In both cases, migration acts to assemble in one high-risk environment thousands of young men highly susceptible to new diseases. With poor living and working conditions, these migration destinations act as hot-spots for disease transmission. Migration of workers back to rural areas then serves as a highly efficient means of disseminating these diseases to rural populations. We conclude by raising some more recent questions examining the current role of migration in Southern Africa. PMID:24653964

  4. Action Stations! 100 years of trauma care on maritime and amphibious operations in the Royal Navy.

    PubMed

    Osborne, M; Smith, J E

    2015-01-01

    Over the past century trauma care within the Royal Navy (RN) has evolved; wartime experiences and military medical research have combined to allow significant improvement in the care of casualties. This article describes the key maritime and amphibious operations that have seen the Royal Navy Medical Service (RNMS) deliver high levels of support to wherever the Naval Service has deployed in the last 100 years. Key advancements in which progress has led to improved outcomes for injured personnel are highlighted--the control and treatment of blood loss, wound care, and the prevention and management of organ failure with optimal resuscitation. Historians often point out how slowly military medicine progressed for the first few thousand years of its recorded history, and how quickly it has progressed in the last century. This reflective article will show how the RNMS has been an integral part of that story, and how the lessons learnt by our predecessors have shaped our modern day doctrine surrounding trauma care. PMID:26292385

  5. [100 years of Draeger Medical Technology (1902 - 2002) -- working for the applicability of oxygen].

    PubMed

    Strätling, M; Schmucker, P

    2004-09-01

    This survey analyses the history of 100 years of Draeger Medical Technology. Between 1889 and 1902 a number of inventions on the field of pressure gas technology allowed to solve application problems, which until then proved major obstacles to the safe and efficient use of compressed gases such as oxygen, nitrous oxide or carbon dioxide for medical and industrial purposes. A special significance is to be awarded here to pressure reducing valves, but also reliable manometers, nozzles and valves for pressure tanks were not generally available until then. These were first successfully and on a really significant scale introduced into international medical and non-medical pressure-gas technology by Draeger Inc. (Luebeck/Germany), and proved particularly successful in anaesthesia and rescue-devices (e. g. in the "Roth-Draeger Anaesthesia Apparatus" (1902). Consequently, starting in 1902, Draeger Inc. increasingly put an emphasis on developing medical and rescue technology and -- by doing so -- gained an important influence on the history of the implementation of modern oxygen therapy and of inhalative anaesthesia. A survey of the historically most important Draeger-Developments is provided. PMID:15490342

  6. The New Horizons Spacecraft

    NASA Astrophysics Data System (ADS)

    Fountain, Glen H.; Kusnierkiewicz, David Y.; Hersman, Christopher B.; Herder, Timothy S.; Coughlin, Thomas B.; Gibson, William C.; Clancy, Deborah A.; Deboy, Christopher C.; Hill, T. Adrian; Kinnison, James D.; Mehoke, Douglas S.; Ottman, Geffrey K.; Rogers, Gabe D.; Stern, S. Alan; Stratton, James M.; Vernon, Steven R.; Williams, Stephen P.

    2008-10-01

    The New Horizons spacecraft was launched on 19 January 2006. The spacecraft was designed to provide a platform for seven instruments designated by the science team to collect and return data from Pluto in 2015. The design meets the requirements established by the National Aeronautics and Space Administration (NASA) Announcement of Opportunity AO-OSS-01. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration consistent with meeting the AO requirement of returning data prior to the year 2020. The spacecraft subsystems were designed to meet tight resource allocations (mass and power) yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto fly-by is 4.5 hours. Missions to the outer regions of the solar system (where the solar irradiance is 1/1000 of the level near the Earth) require a radioisotope thermoelectric generator (RTG) to supply electrical power. One RTG was available for use by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on approximately 200 W. The travel time to Pluto put additional demands on system reliability. Only after a flight time of approximately 10 years would the desired data be collected and returned to Earth. This represents the longest flight duration prior to the return of primary science data for any mission by NASA. The spacecraft system architecture provides sufficient redundancy to meet this requirement with a probability of mission success of greater than 0.85. The spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015. Initial in-flight tests have verified that the spacecraft will meet the design requirements.

  7. Time- and Oil-Dependent Transcriptomic and Physiological Responses to Deepwater Horizon Oil in Mahi-Mahi (Coryphaena hippurus) Embryos and Larvae.

    PubMed

    Xu, Elvis Genbo; Mager, Edward M; Grosell, Martin; Pasparakis, Christina; Schlenker, Lela S; Stieglitz, John D; Benetti, Daniel; Hazard, E Starr; Courtney, Sean M; Diamante, Graciel; Freitas, Juliane; Hardiman, Gary; Schlenk, Daniel

    2016-07-19

    The Deepwater Horizon (DWH) oil spill contaminated the spawning habitats for numerous commercially and ecologically important fishes. Exposure to the water accommodated fraction (WAF) of oil from the spill has been shown to cause cardiac toxicity during early developmental stages across fishes. To better understand the molecular events and explore new pathways responsible for toxicity, RNA sequencing was performed in conjunction with physiological and morphological assessments to analyze the time-course (24, 48, and 96 h post fertilization (hpf)) of transcriptional and developmental responses in embryos/larvae of mahi-mahi exposed to WAF of weathered (slick) and source DWH oils. Slick oil exposure induced more pronounced changes in gene expression over time than source oil exposure. Predominant transcriptomic responses included alteration of EIF2 signaling, steroid biosynthesis, ribosome biogenesis and activation of the cytochrome P450 pathway. At 96 hpf, slick oil exposure resulted in significant perturbations in eye development and peripheral nervous system, suggesting novel targets in addition to the heart may be involved in the developmental toxicity of DHW oil. Comparisons of changes of cardiac genes with phenotypic responses were consistent with reduced heart rate and increased pericardial edema in larvae exposed to slick oil but not source oil. PMID:27348429

  8. PREFACE: Celebrating 100 years of superconductivity: special issue on the iron-based superconductors Celebrating 100 years of superconductivity: special issue on the iron-based superconductors

    NASA Astrophysics Data System (ADS)

    Crabtree, George; Greene, Laura; Johnson, Peter

    2011-12-01

    In honor of this year's 100th anniversary of the discovery of superconductivity, this special issue of Reports on Progress in Physics is a dedicated issue to the 'iron-based superconductors'—a new class of high-temperature superconductors that were discovered in 2008. This is the first time the journal has generated a 'theme issue', and we provide this to the community to provide a 'snapshot' of the present status, both for researchers working in this fast-paced field, and for the general physics community. Reports on Progress in Physics publishes three classes of articles—comprehensive full Review Articles, Key Issues Reviews and, most recently, Reports on Progress articles that recount the current status of a rapidly evolving field, befitting of the articles in this special issue. It has been an exciting year for superconductivity—there have been numerous celebrations for this centenary recounting the fascinating history of this field, from seven Nobel prizes to life-saving discoveries that brought us medically useful magnetic resonance imaging. The discovery of a completely new class of high-temperature superconductors, whose mechanism remains as elusive as the cuprates discovered in 1986, has injected a new vitality into this field, and this year those new to the field were provided with the opportunity of interacting with those who have enjoyed a long history in superconductivity. Furthermore, as high-density current carriers with little or no power loss, high-temperature superconductors offer unique solutions to fundamental grid challenges of the 21st century and hold great promise in addressing our global energy challenges. The complexity and promise of these materials has caused our community to more freely share our ideas and results than ever before, and it is gratifying to see how we have grown into an enthusiastic global network to advance the field. This invited collection is true to this agenda and we are delighted to have received contributions

  9. To Humbly Go: Guarding Against Perpetuating Models of Colonization in the 100-Year Starship Study

    NASA Astrophysics Data System (ADS)

    Kramer, W. R.

    Past patterns of exploration, colonization and exploitation on Earth continue to provide the predominant paradigms that guide many space programs. Any project of crewed space exploration, especially of the magnitude envisioned by the 100-Year Starship Study, must guard against the hubris that may emerge among planners, crew, and others associated with the project, including those industries and bureaucracies that will emerge from the effort. Maintaining a non-exploitative approach may be difficult in consideration of the century of preparatory research and development and the likely multigenerational nature of the voyage itself. Starting now with mission dreamers and planners, the purpose of the voyage must be cast as one of respectful learning and humble discovery, not of conquest (either actual or metaphorical) or other inappropriate models, including military. At a minimum, the Study must actively build non-violence into the voyaging culture it is beginning to create today. References to exploitive colonization, conquest, destiny and other terms from especially American frontier mythology, while tempting in their propagandizing power, should be avoided as they limit creative thinking about alternative possible futures. Future voyagers must strive to adapt to new environments wherever possible and be assimilated by new worlds both biologically and behaviorally rather than to rely on attempts to recreate the Earth they have left. Adaptation should be strongly considered over terraforming. This paper provides an overview of previous work linking the language of colonization to space programs and challenges the extension of the myth of the American frontier to the Starship Study. It argues that such metaphors would be counter-productive at best and have the potential to doom long-term success and survival by planting seeds of social decay and self-destruction. Cautions and recommendations are suggested.

  10. Semiclassical ultraextremal horizons

    SciTech Connect

    Matyjasek, Jerzy; Zaslavskii, O.B.

    2005-04-15

    We examine backreaction of quantum massive fields on multiply-degenerate (ultraextremal) horizons. It is shown that, under influence of the quantum backreaction, the horizon of such a kind moves to a new position near which the metric does not change its asymptotics, so the ultraextremal black holes and cosmological spacetimes do exist as self-consistent solutions of the semiclassical field equations.

  11. The 2011 Horizon Report

    ERIC Educational Resources Information Center

    Johnson, L.; Smith, R.; Willis, H.; Levine, A.; Haywood, K.

    2011-01-01

    The internationally recognized series of "Horizon Reports" is part of the New Media Consortium's Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming five years on a variety of sectors around the globe. This volume, the "2011 Horizon…

  12. Two Horizons of Fusion

    ERIC Educational Resources Information Center

    Lo, Mun Ling; Chik, Pakey Pui Man

    2016-01-01

    In this paper, we aim to differentiate the internal and external horizons of "fusion." "Fusion" in the internal horizon relates to the structure and meaning of the object of learning as experienced by the learner. It clarifies the interrelationships among an object's critical features and aspects. It also illuminates the…

  13. The 2010 Horizon Report

    ERIC Educational Resources Information Center

    Johnson, L.; Levine, A.; Smith, R.; Stone, S.

    2010-01-01

    The annual "Horizon Report" describes the continuing work of the New Media Consortium's Horizon Project, a qualitative research project established in 2002 that identifies and describes emerging technologies likely to have a large impact on teaching, learning, or creative inquiry on college and university campuses within the next five years. The…

  14. Fuzziness at the horizon

    NASA Astrophysics Data System (ADS)

    Batic, Davide; Nicolini, Piero

    2010-08-01

    We study the stability of the noncommutative Schwarzschild black hole interior by analysing the propagation of a massless scalar field between the two horizons. We show that the spacetime fuzziness triggered by the field higher momenta can cure the classical exponential blue-shift divergence, suppressing the emergence of infinite energy density in a region nearby the Cauchy horizon.

  15. Infrared survey of 50 buildings constructed during 100 years: thermal performances and damage conditions

    NASA Astrophysics Data System (ADS)

    Ljungberg, Sven-Ake

    1995-03-01

    Different building constructions and craftsmanship give rise to different thermal performance and damage conditions. The building stock of most industrial countries consists of buildings of various age, and constructions, from old historic buildings with heavy stone or wooden construction, to new buildings with heavy or light concrete construction, or modern steel or wooden construction. In this paper the result from a detailed infrared survey of 50 buildings from six Swedish military camps is presented. The presentation is limited to a comparison of thermal performance and damage conditions of buildings of various ages, functions, and constructions, of a building period of more than 100 years. The result is expected to be relevant even to civilian buildings. Infrared surveys were performed during 1992-1993, with airborne, and mobile short- and longwave infrared systems, out- and indoor thermography. Interpretation and analysis of infrared data was performed with interactive image and analyzing systems. Field inspections were carried out with fiber optics system, and by ocular inspections. Air-exchange rate was measured in order to quantify air leakages through the building envelope, indicated in thermograms. The objects studied were single-family houses, barracks, office-, service-, school- and exercise buildings, military hotels and restaurants, aircraft hangars, and ship factory buildings. The main conclusions from this study are that most buildings from 1880 - 1940 have a solid construction with a high quality of craftsmanship, relatively good thermal performance, due to extremely thick walls, and adding insulation at the attic floor. From about 1940 - 1960 the quality of construction, thermal performance and craftsmanship seem to vary a lot. Buildings constructed during the period of 1960 - 1990 have in general the best thermal performance due to a better insulation capacity, however, also one finds here the greatest variety of problems. The result from this

  16. Climatic and Hydrological Changes of Past 100 Years in Asian Arid Zone

    NASA Astrophysics Data System (ADS)

    Feng, Zhaodong; Salnikov, Vitaliy; Xu, Changchun

    2014-05-01

    The Asian Arid Zone (AAZ) is here defined to include the following regions: northwestern China, Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. Generally speaking, the AAZ has experienced a temperature rising during the past 100 years that was significantly faster than the global average (0.14 ºC per decade). Specifically, the rate was 0.39 ºC per decade in northwestern China (1950-2010), 0.26 ºC per decade in Kazakhstan (1936-2005), 0.22 ºC per decade in Mongolia (1940-2010), 0.29 ºC per decade in Uzbekistan (1950-2005), 0.18 ºC per decade in Turkmenistan (1961-1995). It should be noted that the mountainous parts of AAZ seems to have experienced a slower rate of temperature rising. For example, the rate was 0.10 ºC per decade in Tajikistan (1940-2005) and was 0.08 ºC per decade in Kyrgyzstan (1890-2005). Precipitation has a slight increasing trend in northwestern China, but it has fluctuated along a near-constant line in the rest of the AAZ. Hydrological data from high-elevation basin show that the runoff has been increasing primarily as a result of rising temperature that caused increases in ice melting. A natural decreasing trend of surface runoff in low-elevation basins is undeniable and the decreasing trend is attributable to intensified evaporation under warming conditions. It is true that the total amount of runoff in the Tianshan Mountains and the associated basins has been increased primarily as a result of temperature rising-resulted increases in ice melting. But, approaching to the turning point of glacier-melting supplies to runoff will pose a great threat to socio-economic sustainability and to ecological security. The turning point refers to the transition from increasing runoff to decreasing runoff within ice melting supplied watersheds under a warming climate.

  17. Geochemical and isotopic time series of oil deposited in Barataria Bay and on Grand Isle, Louisiana, after the Deepwater Horizon Oil Spill

    NASA Astrophysics Data System (ADS)

    Finkelstein, D. B.; Schimmelmann, A.; Rosenheim, B. E.

    2012-12-01

    We present time-series of bulk hydrocarbon geochemical and compound specific isotopic data of oiled and tarry sediment deposits from Grand Isle and Barataria Bay, Louisiana. Samples were taken between 46 days and 694 days after the Macondo well blowout, and analyzed for bulk hydrocarbon stable carbon and hydrogen isotope ratios, n-alkane and other organic molecular characteristics, ramped pyrolysis stable carbon ratios and radiocarbon content, and compound specific isotope analysis. Bulk and compound specific stable hydrogen isotopes point to slight 2H-enrichment attributable to water washing during transport to Grand Isle and Barataria Bay, followed by more subtle changes after deposition that depended in part on the wave energy available locally. Characterization of the n-alkane distributions through time identified subtle shifts in the dominant n-alkanes from water washing and terrestrial degradation. The loss of high molecular weight n-alkanes and an increase in the unresolved complex mixture after day 337 is consistent with a shift from slight to moderate biodegradation. More significant variations were observed in elemental H:C ratios, whereas bulk stable carbon isotope values showed small increases through time. Ramped pyrolysis analyses illustrated relatively volatile and reactive petroleum-derived components were present during the first year following the spill, but they ultimately became less apparent during later sampling. Isotope results from different ramped pyrolysis components are discussed. Compound specific isotope analysis indicate that a combination of variables (e.g., tidal water washing and biodegradation) may impact degradation during the first 200 days. This period was followed by a mixing of Macondo and non-Macondo hydrocarbons in the environment. In sum, our analyses show the complementary roles of abiotic and biotic factors in degradation of the Deepwater Horizon oil that was deposited in different environments of coastal Louisiana.

  18. Changing patterns of infant death over the last 100 years: autopsy experience from a specialist children's hospital

    PubMed Central

    Pryce, JW; Weber, MA; Ashworth, MT; Roberts, SEA; Malone, M; Sebire, NJ

    2012-01-01

    Objectives Infant mortality has undergone a dramatic reduction in the UK over the past century because of improvements in public health policy and medical advances. Postmortem examinations have been performed at Great Ormond Street Hospital for over 100 years, and analysis of cases across this period has been performed to assess changing patterns of infant deaths undergoing autopsy. Design Autopsy reports from 1909 and 2009 were examined. Age, major pathology and cause of death was reviewed from these cases and entered into an anonymized database. A subsequent comparative analysis was performed. Setting All postmortems performed and reported at Great Ormond Street Hospital in 1909 and 2009. Participants Infant deaths, aged 0–365 days, were identified and subsequently analysed for the two years. Main outcome measures Comparative proportional analysis of postmortem findings from the two time periods. Results Three-hundred and fifty-seven and 347 autopsy reports were identified from 1909 and 2009 including 178 and 128 infant deaths, respectively. The commonest cause of death in 1909 was infection (74%) compared to 20% of deaths in 2009. The most frequent final ‘diagnosis’ in 2009 was ‘unexplained sudden unexpected infant death (SUDI)’, despite a full postmortem including ancillary investigations. In contrast, there were no such cases recorded in 1909, but there were frequent deaths due to gastroenteritis and malnutrition together accounting for 16% of cases, compared to one case of gastroenteritis in 2009. Fifteen percent of 1909 cases had infections which are almost never fatal with appropriate treatment in 2009, including tuberculosis, diphtheria and syphilis. Congenital anomalies were detected with similar frequencies at both time points, (21% and 19% in 1909 and 2009, respectively). Conclusion In the UK, significant changes in patterns of pathology have occurred in paediatric autopsy cases performed at a single specialist centre. Fatal infections and

  19. ANNUS MIRABILIS. PHYSICS OF OUR DAYS: Geometry and Physics after 100 Years of Einstein's Relativity (5-8 April 2005)

    NASA Astrophysics Data System (ADS)

    Braginsky, Vladimir B.

    2005-06-01

    As part of the celebration of the World Year of Physics, the Conference "Geometry and Physics after 100 Years of Einstein's Relativity" was held in Golm, near Potsdam, Germany, on April 5-8, 2005. The Conference was organized by the Max Planck Institute for Gravitational Physics (also known as the Albert Einstein Institute), which is celebrating its 10th anniversary in 2005. Conference participants discussed progress made in theoretical and experimental research during the 100 years since the publication of Einstein's famous papers in 1905, the year which has gone down in history as 'Albert Einstein's ANNUS MIRABILIS'.

  20. A technique for estimating heights reached by the 100-year flood on unregulated, nontidal streams in North Carolina

    USGS Publications Warehouse

    Coble, R.W.

    1979-01-01

    A method for estimating the heights reached by floods having a recurrence interval of 100 years is defined for nontidal streams with unregulated flows in North Carolina. The flood heights are the vertical distance between stream stage at median discharge (50 percent duration) and the 100-year flood stage and are defined for streams draining areas between 1 and 10,000 square miles for each of the three physiographic areas in the State. An illustrated example of how the method can be used in conjunction with topographic maps to estimate flood heights and delineate inundated areas by interpolation is given.

  1. New Horizons at Pluto

    NASA Astrophysics Data System (ADS)

    Schenk, Paul; Nimmo, Francis

    2016-06-01

    The New Horizons mission has revealed Pluto and its moon Charon to be geologically active worlds. The familiar, yet exotic, landforms suggest that geologic processes operate similarly across the Solar System, even in its cold outer reaches.

  2. Infrared horizon locator

    NASA Technical Reports Server (NTRS)

    Jalink, A., Jr. (Inventor)

    1973-01-01

    A precise method and apparatus for locating the earth's infrared horizon from space that is independent of season and latitude is described. First and second integrations of the earth's radiance profile are made from space to earth with the second delayed with respect to the first. The second integration is multiplied by a predetermined constant R and then compared with the first integration. When the two are equal the horizon is located.

  3. The anticipated spatial loss of microtidal beaches in the next 100 years due to sea level rise.

    NASA Astrophysics Data System (ADS)

    Alexandrakis, G.; Poulos, S.

    2012-04-01

    The anticipated sea level rise is expected to influence on a global scale the earth coast in the near future and it is considered to be a main factor related to coastal retreat, with beach zones being among the most vulnerable coastal landforms. Records for the period 1890-1990 have shown that sea level has already risen by 18cm (min: +10cm, max: +25cm), while the projected to 2100 sea level rise has estimated to be 20 to 50cm (IPCC, 2007). It has to be highlighted that a small rise of few tens of meters would cause shoreline retreat of a few to tens meters in the case of low lying coasts, i.e. beach zones (e.g. Bruun 1962, Nichol and Letherman, 1995, Ciavola and Corbau, 2002). Within the concept of climate change, sea level rise could also being related, in regional scale, to changes of meteorological factors such as intensity, duration and direction of the onshore blowing winds, variation in atmospheric pressure. In the microtidal Greek waters temporary changes in sea level exceeds the 1 m (HHS, 2004) This work investigates the impact of sea level rise to sixteen beach zones along the Greek coast. More specifically, shoreline retreat has been estimated for time periods of 10, 20, 50 and 100 years for the corresponding sea level rise of 0,038, 0,076m, 0,19m and 0,38m, according to the A1B scenario of IPCC (2007) and utilizing Dean's (1991) equation; the latter includes in the calculations both the effects of the anticipated sea level rise and the associated storm surge The appropriate morphodynamic and sedimentological data used for the estimation of beach retreat has been deduced from field measurements. Finally, the percentage of the sub-aerial area lost for each beach zone, under investigation, has been estimated. The results show that coastline retreat follows a liner increase in the case of eleven out of the 16 beach zones, for a time period of 100 years. Santava beach zone (inner Messiniakos Gulf) undergoes most of erosion in the first period of 20 years

  4. The Bee Disease Diagnostic Service - 100 Years and Growing at the USDA Bee Research laboratory, Beltsville, MD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article discusses the history of honey bee research in the Washington, D.C. area including the 100 year old bee disease diagnostic service available for beekeepers and apiary inspectors. This service provides the Bee Research Laboratory with first-hand knowledge of the problems facing the beek...

  5. Looking toward the Future: New Research Helps Black Sororities and Fraternities Consider New Governing Structures for the Next 100 Years

    ERIC Educational Resources Information Center

    Ruffins, Paul

    2004-01-01

    From a historical perspective, it's interesting to note that at their 100-year mark Black fraternities and sororities are facing some of the very same political criticisms encountered half a century ago. The Black Greeks' ability to be a greater force for social change is also constrained by the basic internal structures of the organizations…

  6. Flood boundaries and water-surface profile for the computed 100-year flood, Swift Creek at Afton, Wyoming, 1986

    USGS Publications Warehouse

    Rankl, James G.; Wallace, Joe C.

    1989-01-01

    Flood flows on Swift Creek near Afton, Wyoming, were analyzed. Peak discharge with an average recurrence interval of 100 years was computed and used to determine the flood boundaries and water surface profile in the study reach. The study was done in cooperation with Lincoln County and the Town of Afton to determine the extent of flooding in the Town of Afton from a 100-year flood on Swift Creek. The reach of Swift Creek considered in the analysis extends upstream from the culvert at Allred County Road No. 12-135 to the US Geological Survey streamflow-gaging station located in the Bridger National Forest , a distance of 3.2 miles. Boundaries of the 100-year flood are delineated on a map using the computed elevation of the flood at each cross section, survey data, and a 1983 aerial photograph. The computed water surface elevation for the 100-year flood was plotted at each cross section, then the lateral extent of the flood was transferred to the flood map. Boundaries between cross sections were sketched using information taken from the aerial photograph. Areas that are inundated, but not part of the active flow, are designated on the cross sections. (Lantz-PTT)

  7. The story of the Hawaiian Volcano Observatory -- A remarkable first 100 years of tracking eruptions and earthquakes

    USGS Publications Warehouse

    Babb, Janet L.; Kauahikaua, James P.; Tilling, Robert I.

    2011-01-01

    The year 2012 marks the centennial of the Hawaiian Volcano Observatory (HVO). With the support and cooperation of visionaries, financiers, scientists, and other individuals and organizations, HVO has successfully achieved 100 years of continuous monitoring of Hawaiian volcanoes. As we celebrate this milestone anniversary, we express our sincere mahalo—thanks—to the people who have contributed to and participated in HVO’s mission during this past century. First and foremost, we owe a debt of gratitude to the late Thomas A. Jaggar, Jr., the geologist whose vision and efforts led to the founding of HVO. We also acknowledge the pioneering contributions of the late Frank A. Perret, who began the continuous monitoring of Kīlauea in 1911, setting the stage for Jaggar, who took over the work in 1912. Initial support for HVO was provided by the Massachusetts Institute of Technology (MIT) and the Carnegie Geophysical Laboratory, which financed the initial cache of volcano monitoring instruments and Perret’s work in 1911. The Hawaiian Volcano Research Association, a group of Honolulu businessmen organized by Lorrin A. Thurston, also provided essential funding for HVO’s daily operations starting in mid-1912 and continuing for several decades. Since HVO’s beginning, the University of Hawaiʻi (UH), called the College of Hawaii until 1920, has been an advocate of HVO’s scientific studies. We have benefited from collaborations with UH scientists at both the Hilo and Mänoa campuses and look forward to future cooperative efforts to better understand how Hawaiian volcanoes work. The U.S. Geological Survey (USGS) has operated HVO continuously since 1947. Before then, HVO was under the administration of various Federal agencies—the U.S. Weather Bureau, at the time part of the Department of Agriculture, from 1919 to 1924; the USGS, which first managed HVO from 1924 to 1935; and the National Park Service from 1935 to 1947. For 76 of its first 100 years, HVO has been

  8. Rescuing 100 Years of Data from the Toronto and Agincourt Magnetic Observatories

    NASA Astrophysics Data System (ADS)

    Springford, A.; Thomson, D. J.; Riegert, D. L.

    2014-12-01

    We have an ongoing project to digitize a geomagnetic record that began in the 1840s at the Toronto magnetic observatory, on what is now the campus of the University of Toronto. As the city of Toronto grew, the observatory was relocated to Agincourt in 1898, and finally to Ottawa in 1968. The record provides a rare opportunity for high resolution study of geomagnetic phenomena far into the past and over a long time scale. The magnetograms, originally recorded on photographic paper, were transferred to 35mm film in the 1980s. We are now converting these film copies to digital images and devising algorithms for unsupervised extraction of the time series data contained therein. Using the digital images, we are able to extract data with a time resolution of approximately 15 seconds, a magnetic resolution of approximately 0.1 nT, and 24-bit quantization. Spectra computed from the extracted time series are characteristic of spectra computed from current digital instruments, indicating that the extracted data are of high quality. Unsupervised extraction is important for reproducibility and because there are in excess of 32,000 images totalling about 500Gb of computer storage. However, given that perfect extraction performance is impossible due to varying image quality, artefacts such as hand-written notes, and quirks of the recording device, we are developing a semi-supervised approach to ensure data quality.

  9. A Centennial Milestone (1910-2010): 100 Years of Youth Suicide Prevention

    ERIC Educational Resources Information Center

    Miller, David N.

    2010-01-01

    Anniversaries are appropriate times for reflecting on the past and planning for the future, and in this 100th anniversary year of Sigmund Freud's famous group meeting--a meeting among a large group of prominent mental health professionals that provides a useful marker and arguable "starting point" for contemporary youth suicide prevention efforts,…

  10. Black holes with bottle-shaped horizons

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Teo, Edward

    2016-06-01

    We present a new class of four-dimensional AdS black holes with noncompact event horizons of finite area. The event horizons are topologically spheres with one puncture, with the puncture pushed to infinity in the form of a cusp. Because of the shape of their event horizons, we call such black holes "black bottles." The solution was obtained as a special case of the Plebański-Demiański solution, and may describe either static or rotating black bottles. For certain ranges of parameters, an acceleration horizon may also appear in the space-time. We study the full parameter space of the solution, and the various limiting cases that arise. In particular, we show how the rotating black hole recently discovered by Klemm arises as a special limit.

  11. Erosion and Deposition Patterns of the Mississippi River as a Result of the "100-Year" Flood Event of April 2011

    NASA Astrophysics Data System (ADS)

    Meyer, D.; Magnani, M.; McIntosh, K. D.

    2011-12-01

    Due to damming in the upper Mississippi River system, rates of sedimentation on the Mississippi River have decreased by more than half since the 1930s, which has resulted in the subsidence of the historic deltaic systems. In order to counteract this trend, the US Army Corps of Engineers (USACE) have diverted most of the Mississippi River sediment flow towards the current deltaic system, although there is concern that current sediment deposition rates may not be enough. Modern land loss along the Mississippi River deltaic plain is a function of many parameters, including the sediment storage and the sediment budget of the river. These parameters are poorly constrained for most rivers. This study explores the possibility of estimating the amount of sediment mobilization during the "100-Year" flood that took place in April 2011 in the portion of the Mississippi River flowing by Memphis, Tennessee. The opportunity to acquire high resolution seismic CHIRP data along the Mississippi River immediately after the flood allows us to compare the new data with similar data acquired in September 2009 in the same part of the river, to evaluate changes sedimentary structures and in the sediment removal/deposition due to the exceptional flooding event. The data were acquired in both cases using an Edgetech SB-512i CHIRP, a 0.7 - 1.2 kHz source pulse, and were recorded to a depth of 5 - 50 m sub-bottom. The compared segments were taken along the same 20 km track of river and comparisons were drawn between them at 9 intersection points. Two main observations can be made from the preliminary analysis of the two datasets: 1) the 2011 data show evidence of widespread erosion and limited deposition. Up to 6 m of alluvium appear to have been eroded from the river bottom. Where sediments have been newly deposited, they are characterized by massive appearance and lack of internal structure; 2) the wavelengths of the sandbars imaged in the post-flood data are 1.5 - 3 times longer than those

  12. The 2010 explosive eruption of Java's Merapi volcano—A '100-year' event

    NASA Astrophysics Data System (ADS)

    Surono; Jousset, Philippe; Pallister, John; Boichu, Marie; Buongiorno, M. Fabrizia; Budisantoso, Agus; Costa, Fidel; Andreastuti, Supriyati; Prata, Fred; Schneider, David; Clarisse, Lieven; Humaida, Hanik; Sumarti, Sri; Bignami, Christian; Griswold, Julie; Carn, Simon; Oppenheimer, Clive; Lavigne, Franck

    2012-10-01

    Merapi volcano (Indonesia) is one of the most active and hazardous volcanoes in the world. It is known for frequent small to moderate eruptions, pyroclastic flows produced by lava dome collapse, and the large population settled on and around the flanks of the volcano that is at risk. Its usual behavior for the last decades abruptly changed in late October and early November 2010, when the volcano produced its largest and most explosive eruptions in more than a century, displacing at least a third of a million people, and claiming nearly 400 lives. Despite the challenges involved in forecasting this 'hundred year eruption', we show that the magnitude of precursory signals (seismicity, ground deformation, gas emissions) was proportional to the large size and intensity of the eruption. In addition and for the first time, near-real-time satellite radar imagery played an equal role with seismic, geodetic, and gas observations in monitoring eruptive activity during a major volcanic crisis. The Indonesian Center of Volcanology and Geological Hazard Mitigation (CVGHM) issued timely forecasts of the magnitude of the eruption phases, saving 10,000-20,000 lives. In addition to reporting on aspects of the crisis management, we report the first synthesis of scientific observations of the eruption. Our monitoring and petrologic data show that the 2010 eruption was fed by rapid ascent of magma from depths ranging from 5 to 30 km. Magma reached the surface with variable gas content resulting in alternating explosive and rapid effusive eruptions, and released a total of ~ 0.44 Tg of SO2. The eruptive behavior seems also related to the seismicity along a tectonic fault more than 40 km from the volcano, highlighting both the complex stress pattern of the Merapi region of Java and the role of magmatic pressurization in activating regional faults. We suggest a dynamic triggering of the main explosions on 3 and 4 November by the passing seismic waves generated by regional earthquakes on

  13. Accuracy assessment of the ERP prediction method based on analysis of 100-year ERP series

    NASA Astrophysics Data System (ADS)

    Malkin, Z.; Tissen, V. M.

    2012-12-01

    A new method has been developed at the Siberian Research Institute of Metrology (SNIIM) for highly accurate prediction of UT1 and Pole motion (PM). In this study, a detailed comparison was made of real-time UT1 predictions made in 2006-2011 and PMpredictions made in 2009-2011making use of the SNIIM method with simultaneous predictions computed at the International Earth Rotation and Reference Systems Service (IERS), USNO. Obtained results have shown that proposed method provides better accuracy at different prediction lengths.

  14. Firewall or smooth horizon?

    NASA Astrophysics Data System (ADS)

    Ori, Amos

    2016-01-01

    Almheiri, Marolf, Polchinski, and Sully pointed out that for a sufficiently old black hole (BH), the set of assumptions known as the complementarity postulates appears to be inconsistent with the assumption of local regularity at the horizon. They concluded that the horizon of an old BH is likely to be the locus of local irregularity, a "firewall". Here I point out that if one adopts a different assumption, namely that semiclassical physics holds throughout its anticipated domain of validity, then the inconsistency is avoided, and the horizon retains its regularity. In this alternative view-point, the vast portion of the original BH information remains trapped inside the BH throughout the semiclassical domain of evaporation, and possibly leaks out later on. This appears to be an inevitable outcome of semiclassical gravity (if assumed to apply throughout its anticipated domain of validity).

  15. 100 years of Cosmic Rays - from the ionisation of air to beyond the LHC

    NASA Astrophysics Data System (ADS)

    Watson, Alan

    2012-03-01

    The study of cosmic rays has impacted on many disciplines, including astrophysics, particle physics, carbon dating and radio astronomy: it has thus had scientific and societal impact. They were discovered in 1912 as a result of the efforts by some of the most distinguished scientists of that era, puzzled by their inability to explain the discharge of ionisation chambers. I will describe some of the early work that led, inter alia, to the discovery of the positron, the muon and the first strange particles and thus to the birth of particle physics. In 1938 it was found that showers of particles that arrive at the earth simultaneously are produced by primary cosmic rays of ˜10^15 eV, about 10^5 times more energetic than any particles that had been contemplated before. I will discuss how study of these showers has led to the discovery of cosmic rays of energies as great as 3 x 10^20 eV, challenging our understanding of where and how they are created. Data from the Pierre Auger Observatory, the largest cosmic-ray detector ever built, is now being used for astrophysical studies and to give glimpses of some hadronic physics at centre-of-mass energies more than 4 times greater than are accessible at the LHC.

  16. Exploring 100+ Year Variability with DASCH: Statistical Methods and Recent Results.

    NASA Astrophysics Data System (ADS)

    Miller, George Franklin; Grindlay, Jonathan E.; Los, Edward

    2014-06-01

    The Digital Access to a Sky Century at Harvard (DASCH) project is currently digitizing the roughly 500,000 photographic plates maintained by the Harvard College Observatory. The Harvard plate collection covers each point of the sky roughly 500 to 3000 times from 1885 to 1992, with limiting magnitudes ranging from B=14-18 mag and photometric accuracy within ±0.1 mag. Production scanning (roughly 400 plates/day) is proceeding in Galactic coordinates from the North Galactic Pole and is currently at roughly 40 degrees galactic latitude. The vastness of these data makes DASCH unique in its ability to systematically study variability on decade-long time scales across the entire sky. We are developing new statistical mining techniques to predictively identify the many classes of stellar variability and explore their long-term behavior, as well as discover new unusual cases/classes of variability. Most recently, we are working to implement wavelet-based algorithms into our mining routines, better allowing us to analyze localized non-periodic signals. Here we report on the progress of our mining and machine learning routines, as well as share several of the exciting new discoveries that are being made with DASCH. We gratefully acknowledge support from NSF grants AST-0407380, AST-0909073 and AST-1313370.

  17. New Horizons Launch Contingency Effort

    NASA Astrophysics Data System (ADS)

    Chang, Yale; Lear, Matthew H.; McGrath, Brian E.; Heyler, Gene A.; Takashima, Naruhisa; Owings, W. Donald

    2007-01-01

    On 19 January 2006 at 2:00 PM EST, the NASA New Horizons spacecraft (SC) was launched from the Cape Canaveral Air Force Station (CCAFS), FL, onboard an Atlas V 551/Centaur/STAR™ 48B launch vehicle (LV) on a mission to explore the Pluto Charon planetary system and possibly other Kuiper Belt Objects. It carried a single Radioisotope Thermoelectric Generator (RTG). As part of the joint NASA/US Department of Energy (DOE) safety effort, contingency plans were prepared to address the unlikely events of launch accidents leading to a near-pad impact, a suborbital reentry, an orbital reentry, or a heliocentric orbit. As the implementing organization. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) had expanded roles in the New Horizons launch contingency effort over those for the Cassini mission and Mars Exploration Rovers missions. The expanded tasks included participation in the Radiological Control Center (RADCC) at the Kennedy Space Center (KSC), preparation of contingency plans, coordination of space tracking assets, improved aerodynamics characterization of the RTG's 18 General Purpose Heat Source (GPHS) modules, and development of spacecraft and RTG reentry breakup analysis tools. Other JHU/APL tasks were prediction of the Earth impact footprints (ElFs) for the GPHS modules released during the atmospheric reentry (for purposes of notification and recovery), prediction of the time of SC reentry from a potential orbital decay, pre-launch dissemination of ballistic coefficients of various possible reentry configurations, and launch support of an Emergency Operations Center (EOC) on the JHU/APL campus. For the New Horizons launch, JHU/APL personnel at the RADCC and at the EOC were ready to implement any real-time launch contingency activities. A successful New Horizons launch and interplanetary injection precluded any further contingency actions. The New Horizons launch contingency was an interagency effort by several organizations. This paper

  18. How Earth works 100 years after Wegener's continental drift theory and IGCP 648

    NASA Astrophysics Data System (ADS)

    Li, Z. X.; Evans, D. A.; Zhong, S.; Eglington, B. M.

    2015-12-01

    It took half a century for Wegener's continental drift theory to be accepted as a fundamental element of the plate tectonic theory. Another half a century on, we are still unsure of the driving mechanism for plate tectonics: is it dominated by thermal convection, gravitational forces, or by a combination of mechanisms? Nonetheless, breakthroughs in the past decades put us in a position to make a major stride in answering this question. These include: (1) widely accepted cyclic occurrences of supercontinent assembly and break-up (whereas random occurrence of supercontinents was an equal possibility in the 1990s); (2) the discovery of two equatorial and antipodal large low seismic velocity provinces (LLSVPs) that dominate the lower mantle and appear to have been the base for almost all mantle plumes since at the Mesozoic, and of subduction of oceanic slabs all the way to the core-mantle boundary, which together suggesting whole-mantle convection; (3) the recognition of true polar wander (TPW) as an important process in Earth history, likely reflecting Earth's major internal mass redistribution events; and (4) rapidly enhancing computer modelling power enabling us to simulate all aspect of Earth's dynamic inner working. Many new yet often controversial ideas have been proposed, such a possible coupling in time (with an offset) and space between supercontinent cycle and superplume (LLSVP) events which oppose to the idea of static and long-lived LLSVPs, and the orthoversion v.s. introversion or extroversion models for supercontinent transition. To fully utilise these advances as well as the rapidly expanding global geoscience databases to address the question of how Earth works, an UNESCO-IUGS sponsored IGCP project No. 648 was formed to coordinate a global cross-disciplinary effort. We aim to achieve a better understanding of the supercontinent cycle, and examine the relationship between supercontinent cycle and global plume events. We will establish a series of global

  19. Sensitivity of potential evaporation estimates to 100 years of climate variability

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Ruud; Stagge, James; Tallaksen, Lena; Witte, Jan-Philip

    2015-04-01

    Evaporation from the vegetated surface is the largest loss term in many, if not the most, water balance studies on earth. As a consequence, an accurate representation of evaporation fluxes is required for appropriate quantification of surface runoff, the soil moisture budget, transpiration, recharge and groundwater processes. However, despite being a key component of the water balance, evaporation figures are usually associated with large uncertainties, as this term is difficult to measure or estimate by modeling. Many modeling frameworks have used the concept of potential evaporation, often estimated for different vegetation classes by multiplying the evaporation from a reference surface ('reference evaporation') with crop specific scaling factors ('crop factors'). Though this two-step potential evaporation approach undoubtedly has practical advantages, the empirical nature of both reference evaporation methods and crop factors limits its usability in extrapolations under non-stationary climatic conditions. We quantified the sensitivity of potential evaporation estimates for different vegetation classes using the two-step approach when calibrated using a non-stationary climate. We used the past century's time series of observed climate, containing non-stationary signals of multi-decadal atmospheric oscillations, global warming, and global dimming/brightening, to evaluate the sensitivity of potential evaporation estimates to the choice and length of the calibration period. We show that using empirical coefficients outside their calibration range may lead to systematic differences between process-based and empirical reference evaporation methods, and systematic errors in estimated potential evaporation components. Our hydrological models are to varying extent regression models, which limits their general applicability, and the estimation of potential evaporation is closely linked to climate variability. With our analysis, we want to raise awareness and to provide a

  20. [100 years of drinking water regulation. Retrospective review, current situation and prospects].

    PubMed

    Rakhmanin, Yu A; Krasovsky, G N; Egorova, N A; Mikhailova, R I

    2014-01-01

    There is considered the history of the development of legislative requirements to the regulation of the quality of drinking water in different countries and international organizations during the period from 1912 to the present time. In terms of comparative analysis there is analyzed the current state of regulatory frameworks of the Russian Federation, WHO, EU, Finland, the UK, Singapore, Australia, Japan, China, Nigeria, the United States and Canada in the field of providing favorable conditions of population drinking water use. There has been noted the significant progress in standardization of the content of the biogenic elements and chemical pollution of drinking water in the absence of uniform requirements to the composition and properties of drinking water globally, that is bound to the need to take into account the national peculiarities of drinking water supply within the separate countries. As promising directions for improving regulation of drinking water quality there are noted: the development of new standards for prioritized water pollution, periodic review ofstandards after appearance of the new scientific data on the biological action of substances, the use of the concept of risk, the harmonization of the normative values and the assessment of the possibility of introduction into the practice the one more criterion of profitableness of population water use--the bioenergetic state of the water. PMID:25051731

  1. Turnover of Species and Guilds in Shrub Spider Communities in a 100-Year Postlogging Forest Chronosequence.

    PubMed

    Haraguchi, Takashi F; Tayasu, Ichiro

    2016-02-01

    Disturbance of forests by logging and subsequent forest succession causes marked changes in arthropod communities. Although vegetation cover provides important habitat for arthropods, studies of the changes in their community structure associated with forest succession have been conducted mostly at ground level. To evaluate how forests of different ages contribute to arthropod biodiversity in shrub habitat, spiders were collected from shrubs in 12 forests ranging in age from 1 to 107 yr after logging. We found marked changes in spider community structure about 10 yr after logging: the number of species and individuals declined rapidly after this time. These changes were likely caused by a decrease in shrub cover in association with forest succession. Changes in spider species composition associated with stand age were small in forests at least 11 yr old and were not clustered by forest age. After the exclusion of species of which we sampled only one or two individuals incidentally, just 0.9 ± 0.5 (mean ± SD) species were unique to these older forests. The other 41.2 ± 4.3 species found in these forests were common to both older and young forests, although some of these species in common were found mainly in forests at least 11 yr old. These results suggest that preservation of old-growth forests contributes to the abundance of these common species, although old-growth forests contribute little to species diversity. PMID:26374757

  2. [Leprosy in Germany 100 years and the early development of anti-leprosy drugs].

    PubMed

    Hundeiker, M; Brömmelhaus, H

    2007-10-01

    Leprosy was nearly eliminated in central Europe by the beginning of 18th century. In the 2nd half of the 19th century, leprosy was imported by Lithuanian rural workers immigrating from the Russian empire into East Prussia. At that time, the ways of infection, the bacteria, and essential diagnostic methods were already known, but there was no effective treatment. A leprosarium was founded in 1899 in Memel. Legislation in 1900 and 1904 regulated the fight against the disease. The patients had to be isolated and not allowed to work with others, in contrast to the situation with cutaneous tuberculosis. Patients with lupus vulgaris, which was not infectious, even had suitable jobs in hospitals. In 1907, Antileprol (Bayer) became available, the first industrial preparation developed from chaulmoogra oils, which had been long used in Indian medicine. The situation of patients, however, remained nearly unchanged, up to the middle of the 20th century, when the first effective mycobacteriostatic agents were introduced. PMID:17673959

  3. [The development of radiotherapy in Denmark through 100 years. From radiology to oncology].

    PubMed

    Sell, A

    1996-01-01

    A short review is given of the development of radiotherapy from its early beginning in 1896 to the establishment of the first three radium centres in 1913/14 which caused strong protest from the surgeons. The Radium Foundation was established on private initiative and was, via money collections, able to finance purchase of radium and in the 1930s erection of new buildings for the three centres. Radiotherapy became a basic specialty from 1950. In the beginning of the 1960s megavoltage therapy was introduced and at the same time chemotherapy was becoming interesting for therapy of solid tumours. This caused a centralisation of the patients to the centres for non-surgical therapy resulting in need for building of two centres (Aalborg and Herlev), and a gradual closing down of the decentral treatment with low voltage equipment in the counties. After 1970 the counties became responsible for the health care including running of the hospitals. This caused a return of some of the patients to decentral treatment facilities, usually the biggest hospital in the county and predominantly for adjuvant or palliative chemotherapy. The speciality has changed name to oncology in 1987. PMID:11625142

  4. The development of radiotherapy in Denmark during 100 years. From radiology to oncology.

    PubMed

    Sell, A

    1995-01-01

    The evolution of radiotherapy in Denmark is traced from its early inception in 1896 to the first three radium centres in 1913-1914, the establishment of which caused a roar of protests among the surgeons of that time. Private initiative pioneered the Radium Foundation which raised money for radium and financed erection of new buildings for the three centres in the 1930's. Radiotherapy became a separate speciality in 1950. The early 1960s saw the introduction of megavoltage therapy and the first promising results from chemotherapeutic management of solid tumors. The consequent referral of patients to centres for non-surgical therapy created a need for two new centres (Aalborg and Herlev) and called for a gradual closing down of decentralized low-voltage treatment at county level. However, the decentralization of health care in 1970 partly reversed this trend and some patients were therefore referred for decentralized treatment at major county hospitals. Such treatment mainly consisted of adjuvant or palliative chemotherapy, though in a few countries palliative therapy was supported by low-voltage therapy. In 1987 the medical speciality of radiotherapy was officially renamed oncology. PMID:8608024

  5. 100 Years of Glacier Photographs: Available Online at the National Snow and Ice Data Center

    NASA Astrophysics Data System (ADS)

    Ballagh, L. M.; Wolfe, J.; Wang, I.; Casey, A.; Fetterer, F.

    2004-12-01

    Historic glacier photographs can be used to study fluctuations in glacier extent over time in response to climate change. Researchers can also use the photographs to approximate changes in glacier terminus location and mass balance. The "Glacier Photograph Collection" at the National Snow and Ice Data Center (NSIDC) contains approximately 5,000 photographs, including both aerial and terrestrial images. NSIDC received funding from the NOAA Climate Database Modernization Program (CDMP) to digitize a portion of the photographs and make an Online Glacier Photograph Database available. The CDMP's primary objective is to preserve climate data and facilitate access to the data. Although digitizing images is expensive, long-term data preservation is a major benefit. When historic photographs are stored on film, images can easily be scratched or damaged. Scanning the images and having them online makes browsing images easier for users. At present, there are 1,313 glacier photographs available online. Additional photos and metadata are being added. The Online Glacier Photograph Database will date from 1883 to 1995, totaling nearly 3,000 photographs available as high resolution TIFF images and lower resolution reference images and thumbnails by the end of 2004. Maintaining accurate metadata records for each photograph is very important. The database is searchable by various fields, including photographer name, photograph date, glacier name, glacier coordinates, state/province, and keyword.

  6. 100-years of Australian bushfire property losses: is the risk significant and is it increasing?

    PubMed

    McAneney, John; Chen, Keping; Pitman, Andy

    2009-06-01

    This study examines the bushfire (wildland fire) risk to the built environment in Australia. The most salient result is that the annual probability of building destruction has remained almost constant over the last century despite large demographic and social changes as well as improvements in fire fighting technique and resources. Most historical losses have taken place in a few extreme fires which if repeated are likely to overwhelm even the most professional of fire services. We also calculate the average annual probability of a random home on the urban-bushland interface being destroyed by a bushfire to be of the order of 1 in 6500, a factor 6.5 times lower than the ignition probability of a structural house fire. Thus on average and if this risk was perceived rationally, the incentive for individual homeowners to mitigate and reduce the bushfire danger even further is low. This being the case and despite predictions of an increasing likelihood of conditions favouring bushfires under global climate change, we suspect that building losses due to bushfires are unlikely to alter materially in the near future. PMID:19410362

  7. Accumulation of Pharmaceuticals, Enterococcus, and Resistance Genes in Soils Irrigated with Wastewater for Zero to 100 Years in Central Mexico

    PubMed Central

    Siebe, Christina; Willaschek, Elisha; Sakinc, Tuerkan; Huebner, Johannes; Amelung, Wulf; Grohmann, Elisabeth; Siemens, Jan

    2012-01-01

    Irrigation with wastewater releases pharmaceuticals, pathogenic bacteria, and resistance genes, but little is known about the accumulation of these contaminants in the environment when wastewater is applied for decades. We sampled a chronosequence of soils that were variously irrigated with wastewater from zero up to 100 years in the Mezquital Valley, Mexico, and investigated the accumulation of ciprofloxacin, enrofloxacin, sulfamethoxazole, trimethoprim, clarithromycin, carbamazepine, bezafibrate, naproxen, diclofenac, as well as the occurrence of Enterococcus spp., and sul and qnr resistance genes. Total concentrations of ciprofloxacin, sulfamethoxazole, and carbamazepine increased with irrigation duration reaching 95% of their upper limit of 1.4 µg/kg (ciprofloxacin), 4.3 µg/kg (sulfamethoxazole), and 5.4 µg/kg (carbamazepine) in soils irrigated for 19–28 years. Accumulation was soil-type-specific, with largest accumulation rates in Leptosols and no time-trend in Vertisols. Acidic pharmaceuticals (diclofenac, naproxen, bezafibrate) were not retained and thus did not accumulate in soils. We did not detect qnrA genes, but qnrS and qnrB genes were found in two of the irrigated soils. Relative concentrations of sul1 genes in irrigated soils were two orders of magnitude larger (3.15×10−3±0.22×10−3 copies/16S rDNA) than in non-irrigated soils (4.35×10−5±1.00×10−5 copies/16S rDNA), while those of sul2 exceeded the ones in non-irrigated soils still by a factor of 22 (6.61×10–4±0.59×10−4 versus 2.99×10−5±0.26×10−5 copies/16S rDNA). Absolute numbers of sul genes continued to increase with prolonging irrigation together with Enterococcus spp. 23S rDNA and total 16S rDNA contents. Increasing total concentrations of antibiotics in soil are not accompanied by increasing relative abundances of resistance genes. Nevertheless, wastewater irrigation enlarges the absolute concentration of resistance genes in soils due to a long-term increase in

  8. Stable predictive control horizons

    NASA Astrophysics Data System (ADS)

    Estrada, Raúl; Favela, Antonio; Raimondi, Angelo; Nevado, Antonio; Requena, Ricardo; Beltrán-Carbajal, Francisco

    2012-04-01

    The stability theory of predictive and adaptive predictive control for processes of linear and stable nature is based on the hypothesis of a physically realisable driving desired trajectory (DDT). The formal theoretical verification of this hypothesis is trivial for processes with a stable inverse, but it is not for processes with an unstable inverse. The extended strategy of predictive control was developed with the purpose of overcoming methodologically this stability problem and it has delivered excellent performance and stability in its industrial applications given a suitable choice of the prediction horizon. From a theoretical point of view, the existence of a prediction horizon capable of ensuring stability for processes with an unstable inverse was proven in the literature. However, no analytical solution has been found for the determination of the prediction horizon values which guarantee stability, in spite of the theoretical and practical interest of this matter. This article presents a new method able to determine the set of prediction horizon values which ensure stability under the extended predictive control strategy formulation and a particular performance criterion for the design of the DDT generically used in many industrial applications. The practical application of this method is illustrated by means of simulation examples.

  9. Boosted apparent horizons

    NASA Astrophysics Data System (ADS)

    Akcay, Sarp

    Boosted black holes play an important role in General Relativity (GR), especially in relation to the binary black hole problem. Solving Einstein vac- uum equations in the strong field regime had long been the holy grail of numerical relativity until the significant breakthroughs made in 2005 and 2006. Numerical relativity plays a crucial role in gravitational wave detection by providing numerically generated gravitational waveforms that help search for actual signatures of gravitational radiation exciting laser interferometric de- tectors such as LIGO, VIRGO and GEO600 here on Earth. Binary black holes orbit each other in an ever tightening adiabatic inspiral caused by energy loss due to gravitational radiation emission. As the orbits shrinks, the holes speed up and eventually move at relativistic speeds in the vicinity of each other (separated by ~ 10M or so where 2M is the Schwarzschild radius). As such, one must abandon the Newtonian notion of a point mass on a circular orbit with tangential velocity and replace it with the concept of black holes, cloaked behind spheroidal event horizons that become distorted due to strong gravity, and further appear distorted because of Lorentz effects from the high orbital velocity. Apparent horizons (AHs) are 2-dimensional boundaries that are trapped surfaces. Conceptually, one can think of them as 'quasi-local' definitions for a black hole horizon. This will be explained in more detail in chapter 2. Apparent horizons are especially important in numerical relativity as they provide a computationally efficient way of describing and locating a black hole horizon. For a stationary spacetime, apparent horizons are 2-dimensional cross-sections of the event horizon, which is itself a 3-dimensional null surface in spacetime. Because an AH is a 2-dimensional cross-section of an event horizon, its area remains invariant under distortions due to Lorentz boosts although its shape changes. This fascinating property of the AH can be

  10. Instability of enclosed horizons

    NASA Astrophysics Data System (ADS)

    Kay, Bernard S.

    2015-03-01

    We point out that there are solutions to the scalar wave equation on dimensional Minkowski space with finite energy tails which, if they reflect off a uniformly accelerated mirror due to (say) Dirichlet boundary conditions on it, develop an infinite stress-energy tensor on the mirror's Rindler horizon. We also show that, in the presence of an image mirror in the opposite Rindler wedge, suitable compactly supported arbitrarily small initial data on a suitable initial surface will develop an arbitrarily large stress-energy scalar near where the two horizons cross. Also, while there is a regular Hartle-Hawking-Israel-like state for the quantum theory between these two mirrors, there are coherent states built on it for which there are similar singularities in the expectation value of the renormalized stress-energy tensor. We conjecture that in other situations with analogous enclosed horizons such as a (maximally extended) Schwarzschild black hole in equilibrium in a (stationary spherical) box or the (maximally extended) Schwarzschild-AdS spacetime, there will be similar stress-energy singularities and almost-singularities—leading to instability of the horizons when gravity is switched on and matter and gravity perturbations are allowed for. All this suggests it is incorrect to picture a black hole in equilibrium in a box or a Schwarzschild-AdS black hole as extending beyond the past and future horizons of a single Schwarzschild (/Schwarzschild-AdS) wedge. It would thus provide new evidence for 't Hooft's brick wall model while seeming to invalidate the picture in Maldacena's ` Eternal black holes in AdS'. It would thereby also support the validity of the author's matter-gravity entanglement hypothesis and of the paper ` Brick walls and AdS/CFT' by the author and Ortíz.

  11. Secretin, 100 years later.

    PubMed

    Chey, William Y; Chang, Ta-Min

    2003-01-01

    One hundred years have elapsed since the discovery of secretin by Bayliss and Starling in 1902. In the past century, the research of secretin has gone by many milestones including isolation, purification and structural determination, chemical synthesis, establishment of its hormonal status by radioimmunoassay and immunoneutralization, identification of the specific receptor, cloning of secretin and its receptor, and identification of a secretin-releasing peptide. It has become clear that secretin is a hormone-regulating pancreatic exocrine secretion of fluid and bicarbonate, gastric acid secretion, and gastric motility. The release and actions of secretin is regulated by hormone-hormonal and neurohormonal interactions. The vagus nerve, particularly its afferent pathway, plays an essential role in the physiological actions of secretin. Substantial information about the property of the secretin receptor has been accumulated, but a potent secretin receptor-specific antagonist remains to be formulated. The neural regulatory mechanisms of the release and action of secretin await further elucidation. The physiological role of secretin in intestinal secretions and motility and extragastrointestinal organs remains to be defined. The presence of secretin and its receptor in the central nervous system is well documented, but its function as a neuropeptide has been recognized gradually and requires extensive study in the future. PMID:14673718

  12. Physics in 100 years

    NASA Astrophysics Data System (ADS)

    Wilczek, Frank

    2016-04-01

    Here I indulge in wide-ranging speculations on the shape of physics, and technology closely related to physics, over the next one hundred years. Themes include the many faces of unification, the re-imagining of quantum theory, and new forms of engineering on small, intermediate, and large scales.

  13. 100 Years of Science

    SciTech Connect

    Carrigan, Dick

    2004-07-07

    The last half-century has seen enormous strides in many scientific and technical areas. In fundamental physics previously unrelated fields like weak interactions and electromagnetism have been linked. Cosmology has been probed back to the Big Bang. Computing and communications have moved from minor topics to subjects that dominate the economy. The structure of DNA has been untangled. We may be on the threshold of understanding the origin of life and even discovering life elsewhere in the universe. Several of these diverse topics such as cosmology and fundamental physics are already profoundly coupled. Remarkably, ties exist between all of these subjects. These ties will be reviewed in light of opportunities ahead in the next decades.

  14. 100 Years of Mathematics.

    ERIC Educational Resources Information Center

    Atiyah, Michael

    2000-01-01

    The 20th century was a period of extraordinary expansion and progress in mathematics. Concentrates on a few key themes that can be discerned such as local to global, increase in dimension, commutative to non-commutative, linear to non-linear, and homology theory, although it is impossible to list all the main achievements. (ASK)

  15. Spacetimes containing slowly evolving horizons

    SciTech Connect

    Kavanagh, William; Booth, Ivan

    2006-08-15

    Slowly evolving horizons are trapping horizons that are ''almost'' isolated horizons. This paper reviews their definition and discusses several spacetimes containing such structures. These include certain Vaidya and Tolman-Bondi solutions as well as (perturbatively) tidally distorted black holes. Taking into account the mass scales and orders of magnitude that arise in these calculations, we conjecture that slowly evolving horizons are the norm rather than the exception in astrophysical processes that involve stellar-scale black holes.

  16. Towards a robust calving and melt-history for Helheim Glacier, SE Greenland, for the last 100 years

    NASA Astrophysics Data System (ADS)

    Andersen, T. J.; Ellegaard, M.; Markussen, T. N.

    2013-12-01

    Observations of increased ice-discharge from tidewater glaciers in Greenland in the early and mid 2000s has led to concern about a possible rapid loss of ice from the ice sheet in a scenario with increasing air and ocean water temperatures. In order to evaluate the strength and uniqueness of the observed increase a robust data-set on the temporal variation of calving and melt is strongly needed. The only reliable data prior to the period of aerial photographs and instrumental observations is the archive preserved at the seabed in the fjords and coastal waters off the ice sheet. Establishment of core-chronology is central in studies of these archives and is based on Pb-210 dating which will reach approx. 100 years back in time. Establishment of a detailed and accurate core-chronology by means of Pb-210 dating and Cs-137 peaks is by no means a trivial task in environments influenced by episodic deposition of ice-rafted debris (IRD). The deposition will have a relatively large component of random variability which could be mistaken for actual changes in sedimentation rate, especially so if only one or a few cores are analyzed. To increase the reliability of the calving reconstruction, a total of 13 cores have been sampled in this study in Sermilik Fjord in August 2012 at depths between approximately 700 to 900 m. Eleven of the cores are from within the central basin north of 66 degrees North and two are from the outer part of the fjord south of that line. CTD-profiles and measurements of floc size in situ indicate that the sedimentation is significantly influenced by deposition of IRD and temporal changes in sediment accumulation rates will therefore be examined for all the cores. The cores are also being analyzed for their content of dinoflagellate cysts and diatoms in order to examine possible temporal changes in ocean water temperature in the fjord. So far (August 2013) six cores have been studied and the total average accumulation rate for each year since 1925 has

  17. Estimated 100-year peak flows and flow volumes in the Big Lost River and Birch Creek at the Idaho National Engineering Laboratory, Idaho

    SciTech Connect

    Kjelstrom, L.C.; Berenbrock, C.

    1996-12-31

    The purpose of this report is to provide estimates of the 100-year peak flows and flow volumes that could enter the INEL area from the Big Lost River and Brich Creek are needed as input data for models that will be used to delineate the extent of the 100-year flood plain at the INEL. The methods, procedures and assumptions used to estimate the 100-year peak flows and flow volumes are described in this report.

  18. Smooth horizons and quantum ripples

    NASA Astrophysics Data System (ADS)

    Golovnev, Alexey

    2015-05-01

    Black holes are unique objects which allow for meaningful theoretical studies of strong gravity and even quantum gravity effects. An infalling and a distant observer would have very different views on the structure of the world. However, a careful analysis has shown that it entails no genuine contradictions for physics, and the paradigm of observer complementarity has been coined. Recently this picture was put into doubt. In particular, it was argued that in old black holes a firewall must form in order to protect the basic principles of quantum mechanics. This AMPS paradox has already been discussed in a vast number of papers with different attitudes and conclusions. Here we want to argue that a possible source of confusion is the neglect of quantum gravity effects. Contrary to widespread perception, it does not necessarily mean that effective field theory is inapplicable in rather smooth neighbourhoods of large black hole horizons. The real offender might be an attempt to consistently use it over the huge distances from the near-horizon zone of old black holes to the early radiation. We give simple estimates to support this viewpoint and show how the Page time and (somewhat more speculative) scrambling time do appear.

  19. Over 100 years of environmental change recorded by foraminifers and sediments in Mobile Bay, Alabama, Gulf of Mexico, USA

    NASA Astrophysics Data System (ADS)

    Osterman, Lisa E.; Smith, Christopher G.

    2012-12-01

    The marine microfauna of Mobile Bay has been profoundly influenced by the development and expansion of the primary shipping channel over the last ˜100 years. Foraminifers and sediments from seven box cores with excess lead-210 chronology document that channel dredging and spoil disposal have altered circulation, reduced estuarine mixing, changed sedimentation patterns, and caused a faunal turnover within the bay. Beginning in the late 1800s, changes in estuarine mixing allowed for greater low-pH freshwater influence in the bay, and ultimately began environmental changes that resulted in the loss of calcareous foraminifers. By the early 1900s, box cores throughout Mobile Bay record a ˜100-year trend of increasing calcareous test dissolution that continues to the present. Since the completion of the current shipping channel in the 1950s, restricted tidal flushing and increased terrestrial organic matter, documented by carbon-to-nitrogen ratios, stimulated an increase in agglutinated foraminiferal densities. However, in deeper areas of the bay, hypoxic water has negatively impacted the marine microfauna. Comparisons of the present-day foraminiferal assemblage with foraminifers collected in the early 1970s indicate that the continued biologic loss of calcareous foraminifers in the bay has allowed the introduction of a new agglutinated foraminiferal species into the bay.

  20. On the Bartnik mass of apparent horizons

    NASA Astrophysics Data System (ADS)

    Mantoulidis, Christos; Schoen, Richard

    2015-10-01

    In this paper we characterize the intrinsic geometry of apparent horizons (outermost marginally outer trapped surfaces) in asymptotically flat spacetimes; that is, the Riemannian metrics on the two sphere which can arise. Furthermore we determine the minimal ADM mass of a spacetime containing such an apparent horizon. The results are conveniently formulated in terms of the quasi-local mass introduced by Bartnik (1989 Phys. Rev. Lett. 62 2346-8). The Hawking mass provides a lower bound for Bartnik’s quasilocal mass on apparent horizons by way of Penrose’s conjecture on time symmetric slices, proven in 1997 by Huisken and Ilmanen (2001 J. Differ. Geom. 59 353-437) and in full generality in 1999 by Bray (2001 J. Differ. Geom. 59 177-267). We compute Bartnik’s mass for all non-degenerate apparent horizons and show that it coincides with the Hawking mass. As a corollary we disprove a conjecture due to Gibbons in the spirit of Thorne’s hoop conjecture (Gibbons 2009 arXiv:0903.1580), and construct a new large class of examples of apparent horizons with the integral of the negative part of the Gauss curvature arbitrarily large.

  1. Effects of 100 years wastewater irrigation on resistance genes, class 1 integrons and IncP-1 plasmids in Mexican soil

    PubMed Central

    Jechalke, Sven; Broszat, Melanie; Lang, Friederike; Siebe, Christina; Smalla, Kornelia; Grohmann, Elisabeth

    2015-01-01

    Long-term irrigation with untreated wastewater can lead to an accumulation of antibiotic substances and antibiotic resistance genes in soil. However, little is known so far about effects of wastewater, applied for decades, on the abundance of IncP-1 plasmids and class 1 integrons which may contribute to the accumulation and spread of resistance genes in the environment, and their correlation with heavy metal concentrations. Therefore, a chronosequence of soils that were irrigated with wastewater from 0 to 100 years was sampled in the Mezquital Valley in Mexico in the dry season. The total community DNA was extracted and the absolute and relative abundance (relative to 16S rRNA genes) of antibiotic resistance genes (tet(W), tet(Q), aadA), class 1 integrons (intI1), quaternary ammonium compound resistance genes (qacE+qacEΔ1) and IncP-1 plasmids (korB) were quantified by real-time PCR. Except for intI1 and qacE+qacEΔ1 the abundances of selected genes were below the detection limit in non-irrigated soil. Confirming the results of a previous study, the absolute abundance of 16S rRNA genes in the samples increased significantly over time (linear regression model, p < 0.05) suggesting an increase in bacterial biomass due to repeated irrigation with wastewater. Correspondingly, all tested antibiotic resistance genes as well as intI1 and korB significantly increased in abundance over the period of 100 years of irrigation. In parallel, concentrations of the heavy metals Zn, Cu, Pb, Ni, and Cr significantly increased. However, no significant positive correlations were observed between the relative abundance of selected genes and years of irrigation, indicating no enrichment in the soil bacterial community due to repeated wastewater irrigation or due to a potential co-selection by increasing concentrations of heavy metals. PMID:25784901

  2. The Horizon Report: 2009 Australia-New Zealand Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Levine, A.; Smith, R.; Smythe, T.; Stone, S.

    2009-01-01

    The New Media Consortium's Horizon Project is an ongoing research project that aims to identify and describe emerging technologies likely to have a large impact on teaching, learning, or creative inquiry within education around the globe over a five-year time period. The project's central products are the "Horizon Reports", an annual series of…

  3. The History of Parenting Practices: An Overview! Events, Policies and Theories That Have Influenced Parenting Practices over the Last 100 Years. [Videotape and Worksheets].

    ERIC Educational Resources Information Center

    1999

    Noting that parenting is a learned experience and that the source of information on parenting has changed considerably over the last 100 years, this videotape examines the history of parent education over the past 100 years, highlighting events influencing family life, policies and legislation to assist families, and parenting theories for each…

  4. New Horizons at Pluto

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Artist's concept of the New Horizons spacecraft as it approaches Pluto and its largest moon, Charon, in July 2015. The craft's miniature cameras, radio science experiment, ultraviolet and infrared spectrometers and space plasma experiments will characterize the global geology and geomorphology of Pluto and Charon, map their surface compositions and temperatures, and examine Pluto's atmosphere in detail. The spacecraft's most prominent design feature is a nearly 7-foot (2.1-meter) dish antenna, through which it will communicate with Earth from as far as 4.7 billion miles (7.5 billion kilometers) away.

  5. Evaluating the 100 year floodplain as an indicator of flood risk in low-lying coastal watersheds

    NASA Astrophysics Data System (ADS)

    Sebastian, A.; Brody, S.; Bedient, P. B.

    2013-12-01

    The Gulf of Mexico is the fastest growing region in the United States. Since 1960, the number of housing units built in the low-lying coastal counties has increased by 246%. The region experiences some of the most intense rainfall events in the country and coastal watersheds are prone to severe flooding characterized by wide floodplains and ponding. This flooding is further exacerbated as urban development encroaches on existing streams and waterways. While the 100 year floodplain should play an important role in our ability to develop disaster resilient communities, recent research has indicated that existing floodplain delineations are a poor indicator of actual flood losses in low-lying coastal regions. Between 2001 and 2005, more than 30% of insurance claims made to FEMA in the Gulf Coast region were outside of the 100 year floodplain and residential losses amounted to more than $19.3 billion. As population density and investments in this region continue to increase, addressing flood risk in coastal communities should become a priority for engineers, urban planners, and decision makers. This study compares the effectiveness of 1-D and a 2-D modeling approaches to spatially capture flood claims from historical events. Initial results indicate that 2-D models perform much better in coastal environments and may serve better for floodplain modeling helping to prevent unintended losses. The results of this study encourage a shift towards better engineering practices using existing 2-D models in order to protect resources and provide guidance for urban development in low-lying coastal regions.

  6. Internet's critical path horizon

    NASA Astrophysics Data System (ADS)

    Valverde, S.; Solé, R. V.

    2004-03-01

    Internet is known to display a highly heterogeneous structure and complex fluctuations in its traffic dynamics. Congestion seems to be an inevitable result of user's behavior coupled to the network dynamics and it effects should be minimized by choosing appropriate routing strategies. But what are the requirements of routing depth in order to optimize the traffic flow? In this paper we analyse the behavior of Internet traffic with a topologically realistic spatial structure as described in a previous study [S.-H. Yook et al., Proc. Natl Acad. Sci. USA 99, 13382 (2002)]. The model involves self-regulation of packet generation and different levels of routing depth. It is shown that it reproduces the relevant key, statistical features of Internet's traffic. Moreover, we also report the existence of a critical path horizon defining a transition from low-efficient traffic to highly efficient flow. This transition is actually a direct consequence of the web's small world architecture exploited by the routing algorithm. Once routing tables reach the network diameter, the traffic experiences a sudden transition from a low-efficient to a highly-efficient behavior. It is conjectured that routing policies might have spontaneously reached such a compromise in a distributed manner. Internet would thus be operating close to such critical path horizon.

  7. Horizon thermodynamics and spacetime mappings

    NASA Astrophysics Data System (ADS)

    Faraoni, Valerio; Vitagliano, Vincenzo

    2014-03-01

    When black holes are dynamical, event horizons are replaced by apparent and trapping horizons. Conformal and Kerr-Schild transformations are widely used in relation to dynamical black holes, and we study the behavior under such transformations of quantities related to the thermodynamics of these horizons, such as the Misner-Sharp-Hernandez mass (internal energy), the Kodama vector, surface gravity, and temperature. The transformation properties are not those expected on the basis of naive arguments.

  8. Sediment records of environmental changes in the south end of the Zhejiang-Fujian coastal mud area during the past 100 years

    NASA Astrophysics Data System (ADS)

    Wang, Linmiao; Li, Guangxue; Gao, Fei; Liu, Ling; Liu, Yong; Dada, Olusegun A.

    2014-07-01

    Previous studies carried out in the East China Sea (ECS) mud area focused on long-term environmental changes in sedimentary records during the Holocene, especially during the mid-Holocene high-stand water levels period. These results indicate that sensitive grain size groups can be used as a sedimentary proxy to reconstruct the evolution of the East Asian Winter Monsoon (EAWM). The studies have been carried out mainly in the northern and middle portions of the Zhejiang-Fujian coastal mud, however, similar research in the southern portion and the comparison between sedimentary proxy and modern measured data of EAWM are lacking. In this paper, we focused on a sedimentary record of the past 100 years with an enhanced resolution of 1.8 years. Investigations of the southern end of the Zhejiang-Fujian coastal mud area were conducted on the basis of 210Pb chronology, grain-size analysis and chemical element analysis. The correspondence between the mean grain size (Mz) of sediment sensitive grain size and the measured EAWM was confi rmed for the fi rst time. We found that during the recent 100 years, the variation of the mean grain size of the sensitive population in the southern portion of the Zhejiang-Fujian mud was mainly controlled by the EAWM intensity changes; and not directly related to changes in the sediment discharge from Datong station of the Changjiang River (DTSD). Finally, recent changes in the content of heavy metals in study area refl ect the impact of human activities on the environment.

  9. Flow and sediment processes in a cutoff meander of the Danube Delta during 100-year recurrent flood

    NASA Astrophysics Data System (ADS)

    Jugaru Tiron, L.; Le Coz, J.; Provansal, M.; Dutu, F.

    2009-04-01

    River training operations, such as meander cutoff, initiated for navigational purposes often lead to dramatic changes in the streamwise profiles (Hooke, 1986, Kesel, 2003; Kiss et al., 2007). Meander correction affects both the hydraulic and morphodynamical behavior of the modified branches that sedimentation occurs in time, while newly built canals usually experience degradation (Jugaru et. al, 2006). This study reports and analyzes new data on the hydrological and sedimentary processes at work during a morphogenic flood in a large modified meander (the Mahmudia meander) of the St. George branch, the southern branch of the Danube Delta. The 100-year recurrent flood that occurred in 2006 offered an exceptional opportunity for scanning different cross sections of the Mahmudia meander system by means of the emerging Doppler profiler (aDcp) technology in order to analyze the impact on sedimentation and dynamic processes in the study area. The Mahmudia study site corresponds to a vast natural meander which was cut off in 1984-1988 by an artificial canal opened to shipping. The meander correction accelerated fluxes through the artificial canal and dramatically enhanced deposition in the former meander. After his formation, the cutoff meander acted as sediment storage locations, essentially removing channel and point bar sediments from the active sediment budget of the main channel (Popa, 1997). During the one-hundred-year recurrent flood in April 2006, bathymetry, flow velocity and discharge data were acquired across several sections of both natural and artificial channels with an acoustic Doppler current profiler (aDcp Workhorse Sentinel 600 kHz, Teledyne RDI) in order to investigate the distribution of the flow and sediment and his impact on sedimentation in a channelized reach and its adjacent cutoff. The contrasting hydro-sedimentary processes at work in both channels and bifurcation/confluence nodal points are analyzed from the measured flux distribution

  10. Transverse deformations of extreme horizons

    NASA Astrophysics Data System (ADS)

    Li, Carmen; Lucietti, James

    2016-04-01

    We consider the inverse problem of determining all extreme black hole solutions to the Einstein equations with a prescribed near-horizon geometry. We investigate this problem by considering infinitesimal deformations of the near-horizon geometry along transverse null geodesics. We show that, up to a gauge transformation, the linearised Einstein equations reduce to an elliptic PDE for the extrinsic curvature of a cross-section of the horizon. We deduce that for a given near-horizon geometry there exists a finite dimensional moduli space of infinitesimal transverse deformations. We then establish a uniqueness theorem for transverse deformations of the extreme Kerr horizon. In particular, we prove that the only smooth axisymmetric transverse deformation of the near-horizon geometry of extreme Kerr, such that cross-sections of the horizon are marginally trapped surfaces, corresponds to that of the extreme Kerr black hole. Furthermore, we determine all smooth and biaxisymmetric transverse deformations of the near-horizon geometry of the five-dimensional extreme Myers-Perry black hole with equal angular momenta. We find a three parameter family of solutions such that cross-sections of the horizon are marginally trapped, which is more general than the known black hole solutions. We discuss the possibility that they correspond to new five-dimensional vacuum black holes.

  11. Technologies on the Horizon: Teachers Respond to the Horizon Report

    ERIC Educational Resources Information Center

    Hodges, Charles B.; Prater, Alyssa H.

    2014-01-01

    The purpose of this study was to investigate teachers' beliefs regarding the integration of technologies from the 2011 K-12 edition of the "Horizon Report" into their local, public school contexts. Teachers read the "Horizon Report" and then participated in an asynchronous, threaded discussion focusing on technologies they…

  12. Aboveground and belowground legacies of native Sami land use on boreal forest in northern Sweden 100 years after abandonment.

    PubMed

    Freschet, Grégoire T; Ostlund, Lars; Kichenin, Emilie; Wardle, David A

    2014-04-01

    Human activities that involve land-use change often cause major transformations to community and ecosystem properties both aboveground and belowground, and when land use is abandoned, these modifications can persist for extended periods. However, the mechanisms responsible for rapid recovery vs. long-term maintenance of ecosystem changes following abandonment remain poorly understood. Here, we examined the long-term ecological effects of two remote former settlements, regularly visited for -300 years by reindeer-herding Sami and abandoned -100 years ago, within an old-growth boreal forest that is considered one of the most pristine regions in northern Scandinavia. These human legacies were assessed through measurements of abiotic and biotic soil properties and vegetation characteristics at the settlement sites and at varying distances from them. Low-intensity land use by Sami is characterized by the transfer of organic matter towards the settlements by humans and reindeer herds, compaction of soil through trampling, disappearance of understory vegetation, and selective cutting of pine trees for fuel and construction. As a consequence, we found a shift towards early successional plant species and a threefold increase in soil microbial activity and nutrient availability close to the settlements relative to away from them. These changes in soil fertility and vegetation contributed to 83% greater total vegetation productivity, 35% greater plant biomass, and 23% and 16% greater concentrations of foliar N and P nearer the settlements, leading to a greater quantity and quality of litter inputs. Because decomposer activity was also 40% greater towards the settlements, soil organic matter cycling and nutrient availability were further increased, leading to likely positive feedbacks between the aboveground and belowground components resulting from historic land use. Although not all of the activities typical of Sami have left visible residual traces on the ecosystem after

  13. Telescopic horizon scanning.

    PubMed

    Koenderink, Jan

    2014-12-20

    The problem of "distortionless" viewing with terrestrial telescopic systems (mainly "binoculars") remains problematic. The so called "globe effect" is only partially counteracted in modern designs. Theories addressing the phenomenon have never reached definitive closure. In this paper, we show that exact distortionless viewing with terrestrial telescopic systems is not possible in general, but that it is in principle possible in-very frequent in battle field and marine applications-the case of horizon scanning. However, this involves cylindrical optical elements. For opto-electronic systems, a full solution is more readily feasible. The solution involves a novel interpretation of the relevant constraints and objectives. For final design decisions, it is not necessary to rely on a corpus of psychophysical (or ergonomic) data, although one has to decide whether the instrument is intended as an extension of the eye or as a "pictorial" device. PMID:25608206

  14. Resolving Lifshitz Horizons

    SciTech Connect

    Harrison, Sarah; Kachru, Shamit; Wang, Huajia; /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC

    2012-04-24

    Via the AdS/CFT correspondence, ground states of field theories at finite charge density are mapped to extremal black brane solutions. Studies of simple gravity + matter systems in this context have uncovered wide new classes of extremal geometries. The Lifshitz metrics characterizing field theories with non-trivial dynamical critical exponent z {ne} 1 emerge as one common endpoint in doped holographic toy models. However, the Lifshitz horizon exhibits mildly singular behaviour - while curvature invariants are finite, there are diverging tidal forces. Here we show that in some of the simplest contexts where Lifshitz metrics emerge, Einstein-Maxwell-dilaton theories, generic corrections lead to a replacement of the Lifshitz metric, in the deep infrared, by a re-emergent AdS{sub 2} x R{sup 2} geometry. Thus, at least in these cases, the Lifshitz scaling characterizes the physics over a wide range of energy scales, but the mild singularity is cured by quantum or stringy effects.

  15. Fluctuating black hole horizons

    NASA Astrophysics Data System (ADS)

    Mei, Jianwei

    2013-10-01

    In this paper we treat the black hole horizon as a physical boundary to the spacetime and study its dynamics following from the Gibbons-Hawking-York boundary term. Using the Kerr black hole as an example we derive an effective action that describes, in the large wave number limit, a massless Klein-Gordon field living on the average location of the boundary. Complete solutions can be found in the small rotation limit of the black hole. The formulation suggests that the boundary can be treated in the same way as any other matter contributions. In particular, the angular momentum of the boundary matches exactly with that of the black hole, suggesting an interesting possibility that all charges (including the entropy) of the black hole are carried by the boundary. Using this as input, we derive predictions on the Planck scale properties of the boundary.

  16. Regime Shifts in Shallow Lakes: Responses of Cyanobacterial Blooms to Watershed Agricultural Phosphorus Loading Over the Last ~100 Years.

    NASA Astrophysics Data System (ADS)

    Vermaire, J. C.; Taranu, Z. E.; MacDonald, G. K.; Velghe, K.; Bennett, E.; Gregory-Eaves, I.

    2015-12-01

    Rapid changes in ecosystem states have occurred naturally throughout Earth's history. However, environmental changes that have taken place since the start of the Anthropocene may be destabilizing ecosystems and increasing the frequency of regime shifts in response to abrupt changes in external drivers or local intrinsic dynamics. To evaluate the relative influence of these forcers and improve our understanding of the impact of future change, we examined the effects of historical catchment phosphorus loading associated with agricultural land use on lake ecosystems, and whether this caused a shift from a stable, clear-water, regime to a turbid, cyanobacteria-dominated, state. The sedimentary pigments, diatom, and zooplankton (Cladocera) records from a currently clear-water shallow lake (Roxton Pond) and a turbid-water shallow lake (Petit lac Saint-François; PSF) were examined to determine if a cyanobacteria associated pigment (i.e. echinenone) showed an abrupt non-linear response to continued historical phosphorus load index (determined by phosphorus budget) over the last ~100 years. While PSF lake is presently in the turbid-water state, pigment and diatom analyses indicated that both lakes were once in the clear-water state, and that non-linear increases in catchment phosphorus balance resulted in an abrupt transition to cyanobacteria dominated states in each record. These results show that phosphorus loading has resulted in state shifts in shallow lake ecosystems that has been recorded across multiple paleolimnological indicators preserved in the sedimentary record.

  17. On the Influence of the NAO on Outlet Glacier Stability in SE Greenland during the Past 100 Years

    NASA Astrophysics Data System (ADS)

    Andresen, C. S.

    2014-12-01

    The Greenland Ice sheet has gained massive attention in recent years due to a sudden increase in mass loss at the onset of this century. A significant part of this mass loss has been attributed to increased ice discharge at the margin through iceberg calving from marine-terminating outlet glaciers. However, due to the lack of instrumental data beyond the past 20-30 years it is difficult to evaluate if this was an outstanding event or if it was part of a recurring phenomenon acting on inter-annual, inter-decadal or centennial timescales. In order to improve understanding of the timescales involved in glacier changes and on the influence of ocean and atmosphere variability we investigate sediment archives from fjords with marine terminating glaciers. Near the glacier margin the sedimentation rates are relatively high due to glacial flour input and rafting of iceberg debris. Our studies of several sediment cores obtained from Sermilik Fjord by Helheim Glacier in Southeast Greenland has allowed us to reconstruct glacier calving, shelf temperature and fjord water renewal rate for the past 100 years. These studies show that dominant modes of climate variability, i.e. the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation, affect ocean properties near the glacier and that the recorded variability concurs with reconstructed outlet glacier changes. This presentation provides an overview these studies.

  18. DNA from a 100-year-old holotype confirms the validity of a potentially extinct hummingbird species

    PubMed Central

    Kirchman, Jeremy J.; Witt, Christopher C.; McGuire, Jimmy A.; Graves, Gary R.

    2010-01-01

    We used mtDNA sequence data to confirm that the controversial 100-year-old holotype of the Bogotá sunangel (Heliangelus zusii) represents a valid species. We demonstrate that H. zusii is genetically well differentiated from taxa previously hypothesized to have given rise to the specimen via hybridization. Phylogenetic analyses place H. zusii as sister to a clade of mid- to high-elevation Andean species currently placed in the genera Taphrolesbia and Aglaiocercus. Heliangelus zusii, presumed extinct, has never been observed in nature by biologists. We infer that the species occupied a restricted distribution between the upper tropical and temperate zones of the northern Andes and that it was most probably driven to extinction by deforestation that accompanied human population growth during the nineteenth and early twentieth centuries. We demonstrate the feasibility of obtaining DNA from nearly microscopic tissue samples from old hummingbird specimens and suggest that these methods could be used to resolve the taxonomy of dozens of avian taxa known only from type specimens. PMID:19776061

  19. The Horizon Report. 2007 Edition

    ERIC Educational Resources Information Center

    New Media Consortium, 2007

    2007-01-01

    This fourth edition of the New Media Consortium's (NMC) annual "Horizon Report" describes the continuing work of the Horizon Project, a research-oriented effort that seeks to identify and describe emerging technologies likely to have a large impact on teaching, learning, or creative expression within higher education. Drawing on ongoing…

  20. The Horizon Report. 2006 Edition

    ERIC Educational Resources Information Center

    New Media Consortium, 2006

    2006-01-01

    This third edition of the New Media Consortium's (NMC) annual "Horizon Report" describes the continuing work of the Horizon Project, a research-oriented effort that seeks to identify and describe emerging technologies likely to have a large impact on teaching, learning, or creative expression within higher education. Drawing on ongoing discussions…

  1. The Horizon Report. 2004 Edition

    ERIC Educational Resources Information Center

    New Media Consortium, 2004

    2004-01-01

    This first edition of the New Media Consortium's (NMC) annual "Horizon Report" details findings of the Horizon Project, a research-oriented effort that seeks to identify and describe emerging technologies likely to have a large impact on teaching, learning, or creative expression within higher education. Drawing on an ongoing series of interviews…

  2. The Horizon Report. 2005 Edition

    ERIC Educational Resources Information Center

    New Media Consortium, 2005

    2005-01-01

    This second edition of the New Media Consortium's (NMC) annual "Horizon Report" describes the continuing work of the Horizon Project, a research-oriented effort that seeks to identify and describe emerging technologies likely to have a large impact on teaching, learning, or creative expression within higher education. Drawing on an ongoing series…

  3. Are We Under-Estimating Mercury in Soils? Experimental Acidification and Sample Collection Timing Demonstrate Variability in Estimates of Mercury in O-Horizon Soils at a Maine Site

    NASA Astrophysics Data System (ADS)

    Nelson, S. J.; Johnson, K. B.

    2009-12-01

    Sampling protocols, including sample timing, collection methods, preservation, and preparation, can strongly influence the results of any analysis. Organic soil horizons are a large pool of mercury (Hg) in most temperate, forested sites; minimizing the potential for under- or over- estimates in this medium is critical for discerning the fate and transport of Hg. Detailed guidance is available for ultra-clean and semi-clean handling for Hg sampling in surface waters. However, neither guidance regarding the proper time of year to sample soils nor methodological studies regarding post-sampling preservation and handling were available in the scientific literature for soil Hg sampling. Here we report on pilot work that (1) provides data for Hg in soils (O-horizon) through an entire year, to determine whether seasonality affects Hg estimates; and (2) documents the effect of treating a soil with acidic water prior to preparation and analysis. We collected O-horizon soil samples monthly from a single plot during 2008, and analyzed them for total Hg. Each month, samples were split; half were ‘control’ samples (dried then analyzed) and half were ‘acidified’ (treated with acidic (pH 2.0) ultrapure water prior to drying and analysis). We observed: (1) a three-fold range of Hg values (148-446 ppb) for the control samples (all collected within the same 2-m2 plot), varying across the twelve months in 2008 during which samples were collected; (2) differences of ~15-20% between acidified and control samples; and, (3) an apparent loss of ~100 ppb of Hg (~22%) if acidification of the dry sample was delayed a day or more. Soils collected when the antecedent period had been wet lost Hg when soils were treated with pH 2.0 solution, potentially because soluble Hg in solution could have been leached during acid treatment. This finding may help to explain why researchers have seen large pulses of Hg in streamwater flux during snowmelt. Further, our results may help to inform

  4. On the differentiability order of horizons

    NASA Astrophysics Data System (ADS)

    Szeghy, D.

    2016-06-01

    Let M be a time oriented Lorentzian manifold and H\\subset M a horizon. We will show that the differentiability order of the horizon can change only once along a generator, i.e. the following holds. If γ :I\\to H is a generator, thus, an inextendable past directed light-like geodesic on the horizon, where I=(α ,β ) or [α ,β ), then there exists a unique parameter {t}0\\in [α ,β ] and a positive integer k≥slant 1 such that the following is true. The horizon H is exactly of class {C}k at γ (t), for every t\\in ({t}0,β ), moreover H is only differentiable, but not of class {C}1 at every point γ (t), for which t\\in (α ,{t}0]. Moreover, if γ (α ) is the endpoint of only one generator then for a suitable space-like submanifold R\\subset H the first cut point of R along γ is γ (α ). Furthermore, all the points γ (t), for which t\\in [α ,{t}0], are non-injectivity points of R along γ . Moreover, if H is smooth at an interior point of γ, then H is smooth at every point of γ. MSC 53C50

  5. What happens to Petrov classification, on horizons of axisymmetric dirty black holes

    SciTech Connect

    Tanatarov, I. V.; Zaslavskii, O. B.

    2014-02-15

    We consider axisymmetric stationary dirty black holes with regular non-extremal or extremal horizons, and compute their on-horizon Petrov types. The Petrov type (PT) in the frame of the observer crossing the horizon can be different from that formally obtained in the usual (but singular in the horizon limit) frame of an observer on a circular orbit. We call this entity the boosted Petrov type (BPT), as the corresponding frame is obtained by a singular boost from the regular one. The PT off-horizon can be more general than PT on-horizon and that can be more general than the BPT on horizon. This is valid for all regular metrics, irrespective of the extremality of the horizon. We analyze and classify the possible relations between the three characteristics and discuss the nature and features of the underlying singular boost. The three Petrov types can be the same only for space-times of PT D and O off-horizon. The mutual alignment of principal null directions and the generator in the vicinity of the horizon is studied in detail. As an example, we also analyze a special class of metrics with utra-extremal horizons (for which the regularity conditions look different from the general case) and compare their off-horizon and on-horizon algebraic structure in both frames.

  6. Current-wave spectra coupling project. Volume I. Hurricane fields and cross sections, surface winds and currents, significant waves and wave spectra for potential OTEC sites: (A) Keahole Point, Hawaii, 100 year hurricane; (B) Punta Tuna, Puerto Rico, 100 year hurricane; (C) New Orleans, Louisiana, 100 year hurricane; (D) West Coast of Florida, 100 year hurricane; and for (E) Hurricane Camille (1969) off Louisiana Coast

    SciTech Connect

    Bretschneider, C.L.

    1980-06-01

    This volume is an extension of and consists of several modifications to the earlier report by Bretschneider (April 1979) on the subject of hurricane design wind, wave and current criteria for the four potential OTEC sites. The 100-year hurricane criteria for the design of OTEC plants is included. The criteria, in addition to the maximum conditions of winds, waves and surface current, include: hurricane fields for wind speed U/sub s/ and significant wave height H/sub s/; hurricane fields for modal wave period f/sub 0//sup -1/ and maximum energy density S/sub max/ of the wave spectrum; the corresponding Ekman wind-driven surface current V/sub s/; tabulated cross-sections for U/sub s/, H/sub s/, f/sub 0//sup -1/ and S/sub max/ through max U/sub s/ and through max H/sub s/ along traverses at right angles to and along traverses parallel to the forward movement of the hurricane; most probable maximum wave height and the expected corresponding wave period, based on statistical analysis of maximum wave heights from five hurricanes; design wave spectra for maximum U/sub s/ and also maximum H/sub s/, since maximum U/sub s/ and maximum H/sub s/ do not occur simultaneously; the envelope of wave spectra through maximum U/sub s/ and through maximum H/sub s/ along traverses parallel to the forward movement of the hurricane; the above same determinations for Hurricane Camille (1969) as for the four OTEC locations; and alternative methods (suggested) for obtaining design wave spectra from the joint probability distribution functions for wave height and period given by Longuet-Higgins (1975) and C.N.E.X.O. after Arhan, et al (1976).

  7. Acidophilic denitrifiers dominate the N2O production in a 100-year-old tea orchard soil.

    PubMed

    Huang, Ying; Long, Xi-En; Chapman, Stephen J; Yao, Huaiying

    2015-03-01

    Aerobic denitrification is the main process for high N2O production in acid tea field soil. However, the biological mechanisms for the high emission are not fully understood. In this study, we examined N2O emission and denitrifier communities in 100-year-old tea soils with four pH levels (3.71, 5.11, 6.19, and 7.41) and four nitrate concentration (0, 50, 200, and 1000 mg kg(-1) of NO3 (-)-N) addition. Results showed the highest N2O emission (10.1 mg kg(-1) over 21 days) from the soil at pH 3.71 with 1000 mg kg(-1) NO3 (-) addition. The N2O reduction and denitrification enzyme activity in the acid soils (pH <7.0) were significantly higher than that of soils at pH 7.41. Moreover, TRF 78 of nirS and TRF 187 of nosZ dominated in soils of pH 3.71, suggesting an important role of acidophilic denitrifiers in N2O production and reduction. CCA analysis also showed a negative correlation between the dominant denitrifier ecotypes (nirS TRF 78, nosZ TRF 187) and soil pH. The representative sequences were identical to those of cultivated denitrifiers from acidic soils via phylogenetic tree analysis. Our results showed that the acidophilic denitrifier adaptation to the acid environment results in high N2O emission in this highly acidic tea soil. PMID:25273518

  8. Snow accumulation rate on Qomolangma (Mount Everest), Himalaya: synchroneity with sites across the Tibetan Plateau on 50-100 year timescales

    NASA Astrophysics Data System (ADS)

    Kaspari, Susan; Hooke, Roger Leb.; Mayewski, Paul Andrew; Kang, Shichang; Hou, Shugui; Qin, Dahe

    Annual-layer thickness data, spanning AD 1534-2001, from an ice core from East Rongbuk Col on Qomolangma (Mount Everest, Himalaya) yield an age-depth profile that deviates systematically from a constant accumulation-rate analytical model. The profile clearly shows that the mean accumulation rate has changed every 50-100 years. A numerical model was developed to determine the magnitude of these multi-decadal-scale rates. The model was used to obtain a time series of annual accumulation. The mean annual accumulation rate decreased from ˜0.8 m ice equivalent in the 1500s to ˜0.3 m in the mid-1800s. From ˜1880 to ˜1970 the rate increased. However, it has decreased since ˜1970. Comparison with six other records from the Himalaya and the Tibetan Plateau shows that the changes in accumulation in East Rongbuk Col are broadly consistent with a regional pattern over much of the Plateau. This suggests that there may be an overarching mechanism controlling precipitation and mass balance over this area. However, a record from Dasuopu, only 125 km northwest of Qomolangma and 700 m higher than East Rongbuk Col, shows a maximum in accumulation during the 1800s, a time during which the East Rongbuk Col and Tibetan Plateau ice-core and tree-ring records show a minimum. This asynchroneity may be due to altitudinal or seasonal differences in monsoon versus westerly moisture sources or complex mountain meteorology.

  9. Social pharmacology: expanding horizons.

    PubMed

    Maiti, Rituparna; Alloza, José Luis

    2014-01-01

    In the current modern and global society, social changes are in constant evolution due to scientific progress (technology, culture, customs, and hygiene) and produce the freedom in individuals to take decisions by themselves or with their doctors toward drug consumption. In the arena of marketed drug products which includes society, individual, administration, and pharmaceutical industry, the young discipline emerged is social pharmacology or sociopharmacology. This science arises from clinical pharmacology, and deals with different parameters, which are important in creating knowledge on marketed drugs. However, the scope of "social pharmacology" is not covered by the so-called "Phase IV" alone, but it is the science that handles the postmarketing knowledge of drugs. The social pharmacology studies the "life cycle" of any marketed pharmaceutical product in the social terrain, and evaluates the effects of the real environment under circumstances totally different in the drug development process. Therefore, there are far-reaching horizons, plural, and shared predictions among health professionals and other, for beneficial use of a drug, toward maximizing the benefits of therapy, while minimizing negative social consequences. PMID:24987168

  10. Social Pharmacology: Expanding horizons

    PubMed Central

    Maiti, Rituparna; Alloza, José Luis

    2014-01-01

    In the current modern and global society, social changes are in constant evolution due to scientific progress (technology, culture, customs, and hygiene) and produce the freedom in individuals to take decisions by themselves or with their doctors toward drug consumption. In the arena of marketed drug products which includes society, individual, administration, and pharmaceutical industry, the young discipline emerged is social pharmacology or sociopharmacology. This science arises from clinical pharmacology, and deals with different parameters, which are important in creating knowledge on marketed drugs. However, the scope of “social pharmacology” is not covered by the so-called “Phase IV” alone, but it is the science that handles the postmarketing knowledge of drugs. The social pharmacology studies the “life cycle” of any marketed pharmaceutical product in the social terrain, and evaluates the effects of the real environment under circumstances totally different in the drug development process. Therefore, there are far-reaching horizons, plural, and shared predictions among health professionals and other, for beneficial use of a drug, toward maximizing the benefits of therapy, while minimizing negative social consequences. PMID:24987168

  11. Apparent horizons in binary black hole spacetimes

    NASA Astrophysics Data System (ADS)

    Shoemaker, Deirdre Marie

    Over the last decade, advances in computing technology and numerical techniques have lead to the possible theoretical prediction of astrophysically relevant waveforms in numerical simulations. With the building of gravitational wave detectors such as the Laser Interferometric Gravitational-Wave Observatory, we stand at the epoch that will usher in the first experimental study of strong field general relativity. One candidate source for ground based detection of gravitational waveforms, the orbit and merger of two black holes, is of great interest to the relativity community. The binary black hole problem is the two-body problem in general relativity. It is a stringent dynamical test of the theory. The problem involves the evolution of the Einstein equation, a complex system of non-linear, dynamic, elliptic-hyperbolic equations intractable in closed form. Numerical relativists are now developing the technology to evolve the Einstein equation using numerical simulations. The generation of these numerical I codes is a ``theoretical laboratory'' designed to study strong field phenomena in general relativity. This dissertation reports the successful development and application of the first multiple apparent horizon tracker applied to the generic binary black hole problem. I have developed a method that combines a level set of surfaces with a curvature flow method. This method, which I call the level flow method, locates the surfaces of any apparent horizons in the spacetime. The surface location then is used to remove the singularities from the computational domain in the evolution code. I establish the following set of criteria desired in an apparent horizon tracker: (1)The robustness of the tracker due to its lack of dependence on small changes to the initial guess; (2)The generality of the tracker in its applicability to generic spacetimes including multiple back hole spacetimes; and (3)The efficiency of the tracker algorithm in CPU time. I demonstrate the apparent

  12. Near-horizon Kerr magnetosphere

    NASA Astrophysics Data System (ADS)

    Gralla, Samuel E.; Lupsasca, Alexandru; Strominger, Andrew

    2016-05-01

    We exploit the near-horizon conformal symmetry of rapidly spinning black holes to determine universal properties of their magnetospheres. Analytic expressions are derived for the limiting form of the magnetosphere in the near-horizon region. The symmetry is shown to imply that the black hole Meissner effect holds for free Maxwell fields but is generically violated for force-free fields. We further show that in the extremal limit, near-horizon plasma particles are infinitely boosted relative to accretion flow. Active galactic nuclei powered by rapidly spinning black holes are therefore natural sites for high-energy particle collisions.

  13. Microbe-mediated transformations of marine dissolved organic matter during 2,100 years of natural incubation in the cold, oxic crust of the Mid-Atlantic Ridge.

    NASA Astrophysics Data System (ADS)

    Shah Walter, S. R.; Jaekel, U.; Huber, J. A.; Dittmar, T.; Girguis, P. R.

    2015-12-01

    On the western flank of the Mid-Atlantic Ridge, oxic seawater from the deep ocean is downwelled into the basaltic crust, supplying the crustal aquifer with an initial inoculum of organic matter and electron acceptors. Studies have shown that fluids circulating within the crust are minimally altered from original seawater, making this subsurface environment a unique natural experiment in which the fate of marine organic matter and the limitations of microbial adaptability in the context of reduced carbon supply can be examined. To make the subsurface crustal aquifer accessible, two CORK (Circulation Obviation Retrofit Kit) observatories have been installed at North Pond, a sediment-filled depression beneath the oligotrophic Sargasso Sea. Radiocarbon analysis of dissolved inorganic (DIC) and organic carbon (DOC) in samples recovered from these observatories show uncoupled aging between DOC and DIC with Δ14C values of DOC as low as -933‰ despite isolation from the open ocean for, at most, 2,100 years. This extreme value is part of a general trend of decreasing DOC δ13C and Δ14C values with increasing incubation time within the aquifer. Combined with reduced concentrations of DOC, our results argue for selective microbial oxidation of the youngest, most 13C-enriched components of downwelled DOC, possibly identifying these as characteristics of the more bioavailable fractions of deep-ocean dissolved organic matter. They also suggest that microbial oxidation during low-temperature hydrothermal circulation could be an important sink for aged marine dissolved organic matter.

  14. [Visual illusions and moving horizon].

    PubMed

    Zhdan'ko, I M; Chulaevskiĭ, A O; Kovalenko, P A

    2012-09-01

    Results of psychological "additional investigation" of the crash of Boeing-737, "Aeroflot-Nord" on 14.09.2008 near Perm are presented. 37 pilots from the one of the leading airline companies sensed the attitude and rolling out the aircraft to the forward flight under the moving horizon with straight display of bank and tangage (view from the aircraft to the ground) in model conditions. 29 pilots (78.4%) made a mistake at determining the roll direction and tangage, they made a mistake at determining the roll direction 61 times (16.4%) and 44 times at determining the tangage direction, in other words they confused left and right bank and also nose-up and nose-down. Visual illusions of mobility of space and handling of ground (instead of aircraft) during the flight were revealed in pilots. These illusions may be the important cause of the following crashes. The necessity of "back" faultless display of bank in all aircrafts of civil aviation and development of computer complex for training of visual spatial orientation is proved. PMID:23156114

  15. Quantum correlations through event horizons: Fermionic versus bosonic entanglement

    SciTech Connect

    Martin-Martinez, Eduardo; Leon, Juan

    2010-03-15

    We disclose the behavior of quantum and classical correlations among all the different spatial-temporal regions of a space-time with an event horizon, comparing fermionic with bosonic fields. We show the emergence of conservation laws for entanglement and classical correlations, pointing out the crucial role that statistics plays in the information exchange (and more specifically, the entanglement tradeoff) across horizons. The results obtained here could shed new light on the problem of information behavior in noninertial frames and in the presence of horizons, giving better insight into the black-hole information paradox.

  16. Quantum correlations through event horizons: Fermionic versus bosonic entanglement

    NASA Astrophysics Data System (ADS)

    Martín-Martínez, Eduardo; León, Juan

    2010-03-01

    We disclose the behavior of quantum and classical correlations among all the different spatial-temporal regions of a space-time with an event horizon, comparing fermionic with bosonic fields. We show the emergence of conservation laws for entanglement and classical correlations, pointing out the crucial role that statistics plays in the information exchange (and more specifically, the entanglement tradeoff) across horizons. The results obtained here could shed new light on the problem of information behavior in noninertial frames and in the presence of horizons, giving better insight into the black-hole information paradox.

  17. Area Theorem and Smoothness of Compact Cauchy Horizons

    NASA Astrophysics Data System (ADS)

    Minguzzi, E.

    2015-10-01

    We obtain an improved version of the area theorem for not necessarily differentiable horizons which, in conjunction with a recent result on the completeness of generators, allows us to prove that under the null energy condition every compactly generated Cauchy horizon is smooth and compact. We explore the consequences of this result for time machines, topology change, black holes and cosmic censorship. For instance, it is shown that compact Cauchy horizons cannot form in a non-empty spacetime which satisfies the stable dominant energy condition wherever there is some source content.

  18. Determination of the 100-year flood plain on Upper Three Runs and selected tributaries, and the Savannah River at the Savannah River site, South Carolina, 1995

    USGS Publications Warehouse

    Lanier, T.H.

    1996-01-01

    The 100-year flood plain was determined for Upper Three Runs, its tributaries, and the part of the Savannah River that borders the Savannah River Site. The results are provided in tabular and graphical formats. The 100-year flood-plain maps and flood profiles provide water-resource managers of the Savannah River Site with a technical basis for making flood-plain management decisions that could minimize future flood problems and provide a basis for designing and constructing drainage structures along roadways. A hydrologic analysis was made to estimate the 100-year recurrence- interval flow for Upper Three Runs and its tributaries. The analysis showed that the well-drained, sandy soils in the head waters of Upper Three Runs reduce the high flows in the stream; therefore, the South Carolina upper Coastal Plain regional-rural-regression equation does not apply for Upper Three Runs. Conse- quently, a relation was established for 100-year recurrence-interval flow and drainage area using streamflow data from U.S. Geological Survey gaging stations on Upper Three Runs. This relation was used to compute 100-year recurrence-interval flows at selected points along the stream. The regional regression equations were applicable for the tributaries to Upper Three Runs, because the soil types in the drainage basins of the tributaries resemble those normally occurring in upper Coastal Plain basins. This was verified by analysis of the flood-frequency data collected from U.S. Geological Survey gaging station 02197342 on Fourmile Branch. Cross sections were surveyed throughout each reach, and other pertinent data such as flow resistance and land-use were col- lected. The surveyed cross sections and computed 100-year recurrence-interval flows were used in a step-backwater model to compute the 100-year flood profile for Upper Three Runs and its tributaries. The profiles were used to delineate the 100-year flood plain on topographic maps. The Savannah River forms the southwestern border

  19. Status of the JPL Horizons Ephemeris System

    NASA Astrophysics Data System (ADS)

    Giorgini, Jon D.

    2015-08-01

    Since 1996, the NASA/Jet Propulsion Laboratory on-line Horizons system has provided open access to the latest JPL orbit solutions through customizable ephemeris generation and searches. Currently, high-precision ephemerides for more than 683,000 objects are available: all known solar system bodies, several dozen spacecraft, system barycenters, and some libration points.Since inception, Horizons has produced 150 million ephemeris products in response to 70.4 million connections by 800,000 unique IP addresses. Recent usage is typically 6000 unique users requesting 4,000,000 ephemeris products per month.Horizons is freely accessible without an account and may be used and automated through any of three interfaces: interactive telnet connection, web-browser form, or by sending e-mail command-files.Asteroid and comet ephemerides are numerically integrated on request using JPL's DASTCOM5 database of initial conditions which is kept current by a separate process; as new measurements and discoveries are reported by the Minor Planet Center, they are automatically processed into new JPL orbit solutions. Radar targets and other objects of high interest have their orbit solutions manually examined and updated into the database.For asteroids and comets, SPK files may be dynamically created using Horizons. This is effectively a recording of the integrator output. The binary files may then be efficiently interpolated by user software to exactly reproduce the trajectory without having to duplicate the numerically integrated n-body dynamical model or PPN equations of motion.Other Horizons output is numerical and in the form of plain-text observer, vector, osculating element, and close-approach tables. More than one hundred quantities can be requested in various time-scales and coordinate systems. For asteroids and comets, statistical uncertainties can be mapped to output times to assess position and motion uncertainties.Horizons is consistent with the DE431 solar system solution

  20. Simulations of the Greenland ice sheet 100 years into the future with the full Stokes model Elmer/Ice

    NASA Astrophysics Data System (ADS)

    Seddik, H.; Greve, R.; Zwinger, T.; Gillet-Chaulet, F.; Gagliardini, O.

    2011-12-01

    the surface precipitation and temperature and the set S (three experiments) applies an amplification factor to change the basal sliding velocity. The experiments are compared to a constant climate control run beginning at present (epoch 2004-1-1 0:0:0) and running up to 100 years holding the climate constant to its present state. The experiments with the amplification factor (Set S) show high sensitivities. Relative to the control run, the scenario with an amplification factor of 3x applied to the sliding velocity produces a Greenland contribution to sea level rise of ~25 cm. An amplification factor of 2.5x produces a contribution of ~16 cm and an amplification factor 2x produces a contribution of ~9 cm. The experiments with the changes to the surface precipitation and temperature (set C) show a contribution to sea level rise of ~4 cm when a factor 1x is applied to the temperature and precipitation anomalies. A factor 1.5x produces a sea level rise of ~8 cm and a factor 2x produces a sea level rise of ~12 cm.

  1. The absence of horizon in black-hole formation

    NASA Astrophysics Data System (ADS)

    Ho, Pei-Ming

    2016-08-01

    With the back-reaction of Hawking radiation taken into consideration, the work of Kawai, Matsuo and Yokokura [1] has shown that, under a few assumptions, the collapse of matter does not lead to event horizon nor apparent horizon. In this paper, we relax their assumptions and elaborate on the space-time geometry of a generic collapsing body with spherical symmetry. The geometry outside the collapsing sphere is found to be approximated by the geometry outside the white-hole horizon, hence the collapsing matter remains outside the Schwarzschild radius. As particles in Hawking radiation are created in the vicinity of the collapsing matter, the information loss paradox is alleviated. Assuming that the collapsing body evaporates within finite time, there is no event horizon.

  2. Dynamical AdS strings across horizons

    NASA Astrophysics Data System (ADS)

    Ishii, Takaaki; Murata, Keiju

    2016-03-01

    We examine the nonlinear classical dynamics of a fundamental string in anti-de Sitter spacetime. The string is dual to the flux tube between an external quark-antiquark pair in {N}=4 super Yang-Mills theory. We perturb the string by shaking the endpoints and compute its time evolution numerically. We find that with sufficiently strong perturbations the string continues extending and plunges into the Poincaré horizon. In the evolution, effective horizons are also dynamically created on the string worldsheet. The quark and antiquark are thus causally disconnected, and the string transitions to two straight strings. The forces acting on the endpoints vanish with a power law whose slope depends on the perturbations. The condition for this transition to occur is that energy injection exceeds the static energy between the quark-antiquark pair.

  3. NEW HORIZONS IN SENSOR DEVELOPMENT

    PubMed Central

    Intille, Stephen S.; Lester, Jonathan; Sallis, James F.; Duncan, Glen

    2011-01-01

    Background Accelerometery and other sensing technologies are important tools for physical activity measurement. Engineering advances have allowed developers to transform clunky, uncomfortable, and conspicuous monitors into relatively small, ergonomic, and convenient research tools. New devices can be used to collect data on overall physical activity and in some cases posture, physiological state, and location, for many days or weeks from subjects during their everyday lives. In this review article, we identify emerging trends in several types of monitoring technologies and gaps in the current state of knowledge. Best practices The only certainty about the future of activity sensing technologies is that researchers must anticipate and plan for change. We propose a set of best practices that may accelerate adoption of new devices and increase the likelihood that data being collected and used today will be compatible with new datasets and methods likely to appear on the horizon. Future directions We describe several technology-driven trends, ranging from continued miniaturization of devices that provide gross summary information about activity levels and energy expenditure, to new devices that provide highly detailed information about the specific type, amount, and location of physical activity. Some devices will take advantage of consumer technologies, such as mobile phones, to detect and respond to physical activity in real time, creating new opportunities in measurement, remote compliance monitoring, data-driven discovery, and intervention. PMID:22157771

  4. Thermal history of the Sabero Coalfield (Southern Cantabrian Zone, NW Spain) as revealed by apatite fission track analyses from tonstein horizons: implications for timing of coalification

    NASA Astrophysics Data System (ADS)

    Botor, Dariusz; Anczkiewicz, Aneta A.

    2015-10-01

    Apatite fission track (AFT) central ages from Carboniferous (Stephanian) tonsteins of the Sabero Coalfield, NW Spain, range from 140.8 ± 7.5 to 65.8 ± 8.1 Ma (Cretaceous), with mean c-axis projected track length values ranging from 12.5 to 13.4 μm. Mean random vitrinite reflectance ( R r) of these samples ranges from 0.91 to 1.20 %, which can be translated into maximum palaeotemperatures of ca. 130 to 180 °C. All analysed samples experienced substantial post-depositional annealing. The considerably younger AFT ages compared to the depositional ages of the samples and R r data indicate the certainty of the occurrence of at least one heating event after the deposition of strata. The unimodal track length distributions, the relatively short mean track length, and the rather low standard deviation (SD) (1.0-1.6 μm) indicate a relatively simple thermal history that could be related to the post-Late Variscan heating event followed by prolonged residence in the apatite partial annealing zone (APAZ). Geological data combined with thermal models of AFT data indicate that Stephanian strata reached the maximum palaeotemperatures in the Permian period, which was therefore the major time of the coalification processes. The Permian magmatic activity was responsible for a high heat flow, which, with the added effect of sedimentary burial, could account for the resetting of the AFT system. It appears that the fault-related hydrothermal activity could have redistributed heat in areas of significant subsidence. Cooling occurred in the Triassic-Cretaceous times after a high heat flow Permian regime. A post-Permian maturation of the Stephanian organic matter is not very likely, since there is no evidence of a high Mesozoic burial that was sufficient to cause a significant increase in the palaeotemperatures. Finally, exhumation and associated erosion rates may possibly have been faster in the Tertiary, causing the present exposure of the studied rocks.

  5. Exact event horizon of a black hole merger

    NASA Astrophysics Data System (ADS)

    Emparan, Roberto; Martínez, Marina

    2016-08-01

    We argue that the event horizon of a binary black hole merger, in the extreme-mass-ratio limit where one of the black holes is much smaller than the other, can be described in an exact analytic way. This is done by tracing in the Schwarzschild geometry a congruence of null geodesics that approaches a null plane at infinity. Its form can be given explicitly in terms of elliptic functions, and we use it to analyze and illustrate the time-evolution of the horizon along the merger. We identify features such as the line of caustics at which light rays enter the horizon, and the critical point at which the horizons touch. We also compute several quantities that characterize these aspects of the merger.

  6. Finding KBO flyby targets for New Horizons

    NASA Astrophysics Data System (ADS)

    Spencer, John; Trilling, David; Buie, Marc; Parker, Alex; Tholen, David; Stern, S. Alan

    2014-08-01

    We propose to continue the search for Kuiper Belt Objects (KBOs) that can be reached by the New Horizons spacecraft after its 2015 Pluto flyby, by following up on KBOs discovered in 2014A. The first flyby of a small (~50 km) KBO would revolutionize our understanding of KBOs, providing information that can be extrapolated to hundreds of thousands of similar KBOs. Our 2011 search discovered two objects that could be targeted with less than twice the fuel that New Horizons has available, during excellent seeing, but seeing was insufficient to achieve this depth over the entire search area in 2012 or 2013. Deepening the search with time allocated in 2014A, taking advantage of lower star density and the shrinking search area, has a chance of finding a targetable object given sufficiently good seeing, especially with Hyper Suprime Cam. 2014B follow-up is essential to produce orbits good enough to determine targetability, and allow recovery in 2015. We will also continue to refine the orbits of other previously discovered objects, including ones that can be observed from a distance by New Horizons on its passage through the Kuiper Belt.

  7. New Horizons Pluto Flyby Guest Operations

    NASA Astrophysics Data System (ADS)

    Simon, M.; Turney, D.; Fisher, S.; Carr, S. S.

    2015-12-01

    On July 14, 2015, after 9.5 years of cruise, NASA's New Horizons spacecraft flew past the Pluto system to gather first images humankind had ever seen on Pluto and its five moons. While much has been discovered about the Pluto system since New Horizons launch in 2006, the system has never been imaged at high resolution and anticipation of the "First Light" of the Pluto system had been anticipated by planetary enthusiasts for decades. The Johns Hopkins Applied Physics Laboratory (APL), which built and operates New Horizons, was the focal point for gathering three distinct groups: science and engineering team members; media and public affairs representatives; and invited public, including VIP's. Guest operations activities were focused on providing information primarily to the invited public and VIP's. High level objectives for the Guest Operations team was set to entertain and inform the general public, offer media reaction shots, and to deconflict activities for the guests from media activities wherever possible. Over 2000 people arrived at APL in the days surrounding closest approach for guest, science or media operations tracks. Reaction and coverage of the Guest Operations events was universally positive and global in impact: iconic pictures of the auditorium waving flags during the moment of closest approach were published in media outlets on every continent. Media relations activities ensured coverage in all key media publications targeted for release, such as the New York Times, Science, Le Monde, and Nature. Social and traditional media coverage of the events spanned the globe. Guest operations activities are designed to ensure that a guest has a memorable experience and leaves with a lifelong memory of the mission and their partnership in the activity. Results, lessons learned, and other data from the New Horizons guest operations activity will be presented and analyzed.

  8. NIF featured on BBC "Horizon"

    ScienceCinema

    Brian Cox

    2010-09-01

    The National Ignition Facility, the world's largest laser system, located at Lawrence Livermore National Laboratory, was featured in the BBC broadcast "Horizon" hosted by physicist Brian Cox. Here is the NIF portion of the program, which was entitled "Can We Make A Star On Earth?" This video is used with the express permission of the BBC.

  9. Common Ground: Expanding Our Horizons.

    ERIC Educational Resources Information Center

    McDevitt, Michele J.

    In "Common Ground: Dialogue, Understanding, and the Teaching of Composition," Kurt Spellmeyer seeks to familiarize students and teachers with the linguistic and cultural no-man's-land separating them. Reinstating the value of two writing conventions often used by traditional students--expressive and commonplaces--can help expand on the horizons of…

  10. New Horizons in Education, 2000.

    ERIC Educational Resources Information Center

    Ho, Kwok Keung, Ed.

    2000-01-01

    This document contains the May and November 2000 issues of "New Horizons in Education," with articles in English and Chinese. The May issue includes the following articles: "A Key to Successful Environmental Education: Teacher Trainees' Attitude, Behaviour, and Knowledge" (Kevin Chung Wai Lui, Eric Po Keung Tsang, Sing Lai Chan); "Critical…

  11. New Horizons Mission to Pluto

    NASA Technical Reports Server (NTRS)

    Delgado, Luis G.

    2011-01-01

    This slide presentation reviews the trajectory that will take the New Horizons Mission to Pluto. Included are photographs of the spacecraft, the launch vehicle, the assembled vehicle as it is being moved to the launch pad and the launch. Also shown are diagrams of the assembled parts with identifying part names.

  12. NIF featured on BBC "Horizon"

    SciTech Connect

    Brian Cox

    2010-01-12

    The National Ignition Facility, the world's largest laser system, located at Lawrence Livermore National Laboratory, was featured in the BBC broadcast "Horizon" hosted by physicist Brian Cox. Here is the NIF portion of the program, which was entitled "Can We Make A Star On Earth?" This video is used with the express permission of the BBC.

  13. Combining multiple data sources for the quantification of snow and glacier melt contributions to streamflow over the last 100 years

    NASA Astrophysics Data System (ADS)

    Stahl, Kerstin; Freudiger, Daphné S.; Kohn, Irene; Seibert, Jan; Weiler, Markus

    2015-04-01

    High alpine headwater catchments are important source areas for many large rivers. There is considerable interest in understanding and predicting the changing hydrological processes in these catchments due to climatic changes. At the same time, high elevation regions tend to be data scarce. The aim of the study is a re-analysis of the changing contributions of snow and glacier melt to streamflow in the river Rhine over the entire 20th Century. The success of quantifying these contributions across scales and over such a long time period depends on the use of all available information. We present the challenges and benefits of combining multiple regional data sources (i) to analyze these changes empirically and (ii) to constrain hydrological modeling in the headwater basins. The reconstruction of gridded meteorological variables for the period 1901-1950 based on an analogue resampling technique created a consistent meteorological forcing over the entire period. Glacier extents from maps of the early 20th Century defined the starting conditions to bridge the time to existing glacier volume and area change data. The analysis of the co-variability and trends in a set of long time series of climate variables and streamflow in unregulated headwaters provided insight into different phases of changing climate-hydrology relations. These signatures, together with the snow water equivalent maps for the last 30 years produced by the SLF and the collection of all available streamflow records provided important benchmarks for model calibration and validation. This work improves the understanding of climate sensitivity in high mountain environments and demonstrates important challenges when modeling partly compensating effects of a changing climate.

  14. Generic isolated horizons and their applications

    PubMed

    Ashtekar; Beetle; Dreyer; Fairhurst; Krishnan; Lewandowski; Wisniewski

    2000-10-23

    The notion of isolated horizons is extended to allow for distortion and rotation. Space-times containing a black hole, itself in equilibrium but possibly surrounded by radiation, satisfy these conditions. The framework has three types of applications: (i) it provides new tools to extract physics from strong field geometry; (ii) it leads to a generalization of the zeroth and first laws of black hole mechanics and sheds new light on the "origin" of the first law; and (iii) it serves as a point of departure for black hole entropy calculations in nonperturbative quantum gravity. PMID:11030951

  15. Art, the Urban Skyscraper, and Horizon Astronomy

    NASA Astrophysics Data System (ADS)

    Mooney, J. D.

    2016-01-01

    This presentation delineates the historiography and the iconography of my urban public sculptures which use skyscrapers as today's standing stones, markers for horizon astronomy. From 1977 to the present time, my work has engaged the public to “look up and see.” Through ephemeral works in the sky and over the water to large-scale rooftop sculptures in Los Angeles, Chicago, Atlanta, and Europe, viewers are oriented to the Milky Way, the summer triangle, and other celestial phenomena. This new urban scale art, transformative in context and gesture, has become part of the new cultural landscape.

  16. Uncertainties of the global-to-regional temperature and precipitation simulations in CMIP5 models for past and future 100 years

    NASA Astrophysics Data System (ADS)

    Zhao, Lilong; Xu, Jianjun; Powell, Alfred M.; Jiang, Zhihong

    2015-10-01

    Global-to-regional surface temperature and precipitation trends are examined based on the CMIP5 model 100 years of historical simulations and another future 100 years following the Representative Concentration Pathway (RCP) emission scenario projection. Different from the ensemble mean approach in the previous studies, the probabilistic multimodal ensemble prediction with Gaussian fitting is used to generate probabilistic simulations. The results show that the averaged precipitation increases slightly with global warming, but the response is not globally uniform. Both historical model simulations and the RCP emission scenario projections suffer from large uncertainties in the selected models and the geographic distribution. The spatial distribution of spreads among the multimodal scenario projections is similar to that in the historical simulations, except the magnitude of spread sharply increases and the region expands equatorward and poleward in surface temperature and precipitation, respectively.

  17. On tunneling across horizons

    NASA Astrophysics Data System (ADS)

    Vanzo, L.

    2011-07-01

    The tunneling method for stationary black holes in the Hamilton-Jacobi variant is reconsidered in the light of some critiques that have been moved against. It is shown that once the tunneling trajectories have been correctly identified the method is free from internal inconsistencies, it is manifestly covariant, it allows for the extension to spinning particles and it can even be used without solving the Hamilton-Jacobi equation. These conclusions borrow support on a simple analytic continuation of the classical action of a pointlike particle, made possible by the unique assumption that it should be analytic in the complexified Schwarzschild or Kerr-Newman space-time. A more general version of the Parikh-Wilczek method will also be proposed along these lines.

  18. The Malcolm horizon: History and future

    NASA Technical Reports Server (NTRS)

    Malcolm, R.

    1984-01-01

    The development of the Malcolm Horizon, a peripheral vision horizon used in flight simulation, is discussed. A history of the horizon display is presented as well as a brief overview of vision physiology, and the role balance plays is spatial orientation. Avenues of continued research in subconscious cockpit instrumentation are examined.

  19. Geometric properties of static Einstein-Maxwell dilaton horizons with a Liouville potential

    SciTech Connect

    Abdolrahimi, Shohreh; Shoom, Andrey A.

    2011-05-15

    We study nondegenerate and degenerate (extremal) Killing horizons of arbitrary geometry and topology within the Einstein-Maxwell-dilaton model with a Liouville potential (the EMdL model) in d-dimensional (d{>=}4) static space-times. Using Israel's description of a static space-time, we construct the EMdL equations and the space-time curvature invariants: the Ricci scalar, the square of the Ricci tensor, and the Kretschmann scalar. Assuming that space-time metric functions and the model fields are real analytic functions in the vicinity of a space-time horizon, we study the behavior of the space-time metric and the fields near the horizon and derive relations between the space-time curvature invariants calculated on the horizon and geometric invariants of the horizon surface. The derived relations generalize similar relations known for horizons of static four- and five-dimensional vacuum and four-dimensional electrovacuum space-times. Our analysis shows that all the extremal horizon surfaces are Einstein spaces. We present the necessary conditions for the existence of static extremal horizons within the EMdL model.

  20. Fermion tunneling from dynamical horizons

    NASA Astrophysics Data System (ADS)

    Di Criscienzo, R.; Vanzo, L.

    2008-06-01

    The instability against emission of fermionic particles by the trapping horizon of an evolving black hole is analyzed and confirmed using the Hamilton-Jacobi tunneling method. This method automatically selects one special expression for the surface gravity of a changing horizon. The results also apply to point masses embedded in an expanding universe. As a bonus of the tunneling method, we gain the insight that the surface gravity still defines a temperature parameter as long as the evolution is sufficiently slow that the black-hole pass through a sequence of quasi-equilibrium states, and that black holes should be semi-classically unstable even in a hypothetical world without bosonic fields.

  1. Penrose inequality and apparent horizons

    SciTech Connect

    Ben-Dov, Ishai

    2004-12-15

    A spherically symmetric spacetime is presented with an initial data set that is asymptotically flat, satisfies the dominant energy condition, and such that on this initial data M<{radical}(A/16{pi}), where M is the total mass and A is the area of the apparent horizon. This provides a counterexample to a commonly stated version of the Penrose inequality, though it does not contradict the true Penrose inequality.

  2. New Horizons Tracks an Asteroid

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The two 'spots' in this image are a composite of two images of asteroid 2002 JF56 taken on June 11 and June 12, 2006, with the Multispectral Visible Imaging Camera (MVIC) component of the New Horizons Ralph imager. In the bottom image, taken when the asteroid was about 3.36 million kilometers (2.1 million miles) away from the spacecraft, 2002 JF56 appears like a dim star. At top, taken at a distance of about 1.34 million kilometers (833,000 miles), the object is more than a factor of six brighter. The best current, estimated diameter of the asteroid is approximately 2.5 kilometers.

    The asteroid observation was a chance for the New Horizons team to test the spacecraft's ability to track a rapidly moving object. On June 13 New Horizons came to within about 102,000 kilometers of the small asteroid, when the spacecraft was nearly 368 million kilometers (228 million miles) from the Sun and about 273 million kilometers (170 million miles) from Earth.

  3. A receding horizon approach for dynamic UAV mission management

    NASA Astrophysics Data System (ADS)

    Cassandras, Christos G.; Li, Wei

    2003-09-01

    We consider a setting where multiple UAVs form a team cooperating to visit multiple targets to collect rewards associated with them. The team objective is to maximize the total reward accumulated over a given time interval. Complicating factors include uncertainties regarding the locations of targets and the effectiveness of collecting rewards, differences among vehicle capabilities, and the fact that rewards are time-varying. We describe a Receding Horizon (RH) control scheme which dynamically assigns vehicles to targets and simultaneously determines associated trajectories. This scheme is based on solving a sequence of optimization problems over a planning horizon and executing them over a shorter action horizon. We also describe a simulated battlespace environment designed to test UAV team missions and to illustrate how the RH scheme can achieve optimal performance with high probability.

  4. Celebrating 100 Years of Flight.

    ERIC Educational Resources Information Center

    Reese, Susan

    2003-01-01

    In honor of the Wright brothers' first flight, the article profiles aviation and aerospace technology programs that are training workers in aviation safety and explorations. Looks at programs from Eastern New Mexico University-Roswell, Pima Community College, and Olathe Northwest High School. (JOW)

  5. 100 Years of Reality Learning

    ERIC Educational Resources Information Center

    Zimpher, Nancy L.; Wright Ron, D.

    2006-01-01

    One may have heard of reality TV, but what about reality learning? The latter is probably a term one hasn't seen much, although it is in many ways a clearer and more concise name for a concept that in 2006 marks its 100th anniversary: cooperative education, or "co-op." Co-op, a break-through idea pioneered at the University of Cincinnati by Herman…

  6. Beyond the veil: Inner horizon instability and holography

    SciTech Connect

    Balasubramanian, Vijay; Levi, Thomas S.

    2004-11-15

    We show that scalar perturbations of the eternal, rotating Banados-Teitelboim-Zanelli (BTZ) black hole should lead to an instability of the inner (Cauchy) horizon, preserving strong cosmic censorship. Because of backscattering from the geometry, plane-wave modes have a divergent stress tensor at the event horizon, but suitable wave packets avoid this difficulty, and are dominated at late times by quasinormal behavior. The wave packets have cuts in the complexified coordinate plane that are controlled by requirements of continuity, single-valuedness, and positive energy. Due to a focusing effect, regular wave packets nevertheless have a divergent stress energy at the inner horizon, signaling an instability. We propose that this instability, which is localized behind the event horizon, is detected holographically as a breakdown in the semiclassical computation of dual conformal field theory (CFT) expectation values in which the analytic behavior of wave packets in the complexified coordinate plane plays an integral role. In the dual field theory, this is interpreted as an encoding of physics behind the horizon in the entanglement between otherwise independent CFTs.

  7. Simulation of water-surface elevations for a hypothetical 100-year peak flow in Birch Creek at the Idaho National Engineering and Environmental Laboratory, Idaho

    SciTech Connect

    Berenbrock, C.; Kjelstrom, L.C.

    1997-10-01

    Delineation of areas at the Idaho National Engineering and Environmental Laboratory that would be inundated by a 100-year peak flow in Birch Creek is needed by the US Department of Energy to fulfill flood-plain regulatory requirements. Birch Creek flows southward about 40 miles through an alluvium-filled valley onto the northern part of the Idaho National Engineering and Environmental laboratory site on the eastern Snake River Plain. The lower 10-mile reach of Birch Creek that ends in Birch Creek Playa near several Idaho National Engineering and Environmental Laboratory facilities is of particular concern. Twenty-six channel cross sections were surveyed to develop and apply a hydraulic model to simulate water-surface elevations for a hypothetical 100-year peak flow in Birch Creek. Model simulation of the 100-year peak flow (700 cubic feet per second) in reaches upstream from State Highway 22 indicated that flow was confined within channels even when all flow was routed to one channel. Where the highway crosses Birch Creek, about 315 cubic feet per second of water was estimated to move downstream--115 cubic feet per second through a culvert and 200 cubic feet per second over the highway. Simulated water-surface elevation at this crossing was 0.8 foot higher than the elevation of the highway. The remaining 385 cubic feet per second flowed southwestward in a trench along the north side of the highway. Flow also was simulated with the culvert removed. The exact location of flood boundaries on Birch Creek could not be determined because of the highly braided channel and the many anthropogenic features (such as the trench, highway, and diversion channels) in the study area that affect flood hydraulics and flow. Because flood boundaries could not be located exactly, only a generalized flood-prone map was developed.

  8. Topological deformation of isolated horizons

    SciTech Connect

    Liko, Tomas

    2008-03-15

    We show that the Gauss-Bonnet term can have physical effects in four dimensions. Specifically, the entropy of a black hole acquires a correction term that is proportional to the Euler characteristic of the cross sections of the horizon. While this term is constant for a single black hole, it will be a nontrivial function for a system with dynamical topologies such as black-hole mergers: it is shown that for certain values of the Gauss-Bonnet parameter, the second law of black-hole mechanics can be violated.

  9. A 100-year Reconstruction of Regional Sea Ice Extent in the Ross and Amundsen-Bellingshausen Seas as Derived from the RICE Ice Core, Coastal West Antarctica

    NASA Astrophysics Data System (ADS)

    Emanuelsson, D. B.; Bertler, N. A. N.; Baisden, W. T.; Keller, E. D.

    2014-12-01

    Antarctic sea ice increased over the past decades. This increase is the result of an increase in the Ross Sea (RS) and along the coast of East Antarctica, whereas the Amundsen-Bellingshausen Seas (ABS) and the Antarctic Peninsula has seen a general decline. Several mechanisms have been suggested as drivers for the regional, complex sea ice pattern, which include changes in ocean currents, wind pattern, as well as ocean and atmospheric temperature. As part of the Roosevelt Island Climate Evolution (RICE) project, a 763 m deep ice core was retrieved from Roosevelt Island (RI; W161° 21', S79°41', 560 m a.s.l.), West Antarctica. The new record provides a unique opportunity to investigate mechanism driving sea ice variability in the RS and ABS sectors. Here we present the water stable isotope record (δD) from the upper part of the RICE core 0-40 m, spanning the time period from 1894 to 2011 (Fig. 1a). Annual δD are correlated with Sea Ice Concentration (SIC). A significant negative (r= -0.45, p≤ 0.05) correlation was found between annual δD and SIC in the eastern RS sector (boxed region in Fig. 1b) for the following months NDJFMA (austral summer and fall). During NDJFMA, RI receives local moisture input from the RS, while during the rest of the year a large extent of this local moisture source area will be covered with sea ice with the exception of the RS Polynya. Concurrently, we observe positive δD and SIC correlations in the ABS, showing a dipole pattern with the eastern RS. For this reason, we suggest that the RICE δD might be used as a proxy for past SIC for the RS and ABS region. There is no overall trend in δD over 100 years (r= -0.08 ‰ dec-1, p= 0.81, 1894-2011). However, we observe a strong increase from 2000-2011 of 17.7 ‰ dec-1(p≤ 0.1), yet the recent δD values and trend of the last decade are not unprecedented (Fig. 1a). We investigate changes in sea surface temperature, atmospheric temperature, inferred surface ocean currents and

  10. Comparison of the 2-, 25-, and 100-year recurrence interval floods computed from observed data with the 1995 urban flood-frequency estimating equations for Georgia

    USGS Publications Warehouse

    Inman, Ernest J.

    1997-01-01

    Flood-frequency relations were computed for 28 urban stations, for 2-, 25-, and 100-year recurrence interval floods and the computations were compared to corresponding recurrence interval floods computed from the estimating equations from a 1995 investigation. Two stations were excluded from further comparisons or analyses because neither station had a significant flood during the period of observed record. The comparisons, based on the student's t-test statistics at the 0.05 level of significance, indicate that the mean residuals of the 25- and 100-year floods were negatively biased by 26.2 percent and 31.6 percent, respectively, at the 26 stations. However, the mean residuals of the 2-year floods were 2.5 percent lower than the mean of the 2-year floods computed from the equations, and were not significantly biased. The reason for this negative bias is that the period of observed record at the 26 stations was a relatively dry period. At 25 of the 26 stations, the two highest simulated peaks used to develop the estimating equations occurred many years before the observed record began. However, no attempt was made to adjust the estimating equations because higher peaks could occur after the period of observed record and an adjustment to the equations would cause an underestimation of design floods.

  11. Variable horizon in a peridynamic medium

    SciTech Connect

    Silling, Stewart A.; Littlewood, David J.; Seleson, Pablo

    2015-12-10

    Here, a notion of material homogeneity is proposed for peridynamic bodies with variable horizon but constant bulk properties. A relation is derived that scales the force state according to the position-dependent horizon while keeping the bulk properties unchanged. Using this scaling relation, if the horizon depends on position, artifacts called ghost forces may arise in a body under a homogeneous deformation. These artifacts depend on the second derivative of the horizon and can be reduced by employing a modified equilibrium equation using a new quantity called the partial stress. Bodies with piecewise constant horizon can be modeled without ghost forces by using a simpler technique called a splice. As a limiting case of zero horizon, both the partial stress and splice techniques can be used to achieve local-nonlocal coupling. Computational examples, including dynamic fracture in a one-dimensional model with local-nonlocal coupling, illustrate the methods.

  12. Variable horizon in a peridynamic medium.

    SciTech Connect

    Silling, Stewart Andrew; Littlewood, David John; Seleson, Pablo

    2014-10-01

    A notion of material homogeneity is proposed for peridynamic bodies with vari- able horizon but constant bulk properties. A relation is derived that scales the force state according to the position-dependent horizon while keeping the bulk properties un- changed. Using this scaling relation, if the horizon depends on position, artifacts called ghost forces may arise in a body under homogeneous deformation. These artifacts de- pend on the second derivative of horizon and can be reduced by use of a modified equilibrium equation using a new quantity called the partial stress . Bodies with piece- wise constant horizon can be modeled without ghost forces by using a technique called a splice between the regions. As a limiting case of zero horizon, both partial stress and splice techniques can be used to achieve local-nonlocal coupling. Computational examples, including dynamic fracture in a one-dimensional model with local-nonlocal coupling, illustrate the methods.

  13. Variable horizon in a peridynamic medium

    DOE PAGESBeta

    Silling, Stewart A.; Littlewood, David J.; Seleson, Pablo

    2015-12-10

    Here, a notion of material homogeneity is proposed for peridynamic bodies with variable horizon but constant bulk properties. A relation is derived that scales the force state according to the position-dependent horizon while keeping the bulk properties unchanged. Using this scaling relation, if the horizon depends on position, artifacts called ghost forces may arise in a body under a homogeneous deformation. These artifacts depend on the second derivative of the horizon and can be reduced by employing a modified equilibrium equation using a new quantity called the partial stress. Bodies with piecewise constant horizon can be modeled without ghost forcesmore » by using a simpler technique called a splice. As a limiting case of zero horizon, both the partial stress and splice techniques can be used to achieve local-nonlocal coupling. Computational examples, including dynamic fracture in a one-dimensional model with local-nonlocal coupling, illustrate the methods.« less

  14. Theory underlying the peripheral vision horizon device

    NASA Technical Reports Server (NTRS)

    Money, K. E.

    1984-01-01

    Peripheral Vision Horizon Device (PVHD) theory states that the likelihood of pilot disorientation in flight is reduced by providing an artificial horizon that provides orientation information to peripheral vision. In considering the validity of the theory, three areas are explored: the use of an artificial horizon device over some other flight instrument; the use of peripheral vision over foveal vision; and the evidence that peripheral vision is well suited to the processing of orientation information.

  15. A MIP Model for Rolling Horizon Surgery Scheduling.

    PubMed

    Luo, Li; Luo, Yong; You, Yang; Cheng, Yuanjun; Shi, Yingkang; Gong, Renrong

    2016-05-01

    Most surgery scheduling is done 1 day in advance. Caused by lack of overall planning, this scheduling scheme often results in unbalanced occupancy time of the operating rooms. So we put forward a rolling horizon mixed integer programming model for the scheduling. Rolling horizon scheduling refers to a scheduling scheme in which cyclic surgical requests are taken into account. Surgical requests are updated daily. The completed surgeries are eliminated, and new surgeries are added to the scheduling list. Considering day-to-day demand for surgery, we develop a non-rolling scheduling model (NRSM) and a rolling horizon scheduling model (RSM). By comparing the two, we find that the quality of surgery scheduling is significantly influenced by the variation in demand from day to day. A rolling horizon scheduling will enable a more flexible planning of the pool of surgeries that have not been scheduled into this main blocks, and hence minimize the idle time of operating rooms. The strategy of the RSM helps balance the occupancy time among operating rooms. Using surgical data from five departments of the West China Hospital (WCH), we generate surgical demands randomly to compare the NRSM and the RSM. The results show the operating rooms' average utilization rate using RSM is significantly higher than when applying NRSM. PMID:27071394

  16. Spectroscopy of a weakly isolated horizon

    NASA Astrophysics Data System (ADS)

    Chen, Ge-Rui; Huang, Yong-Chang

    2016-06-01

    The spectroscopy of a weakly isolated horizon has been investigated. We obtain an equally spaced entropy spectrum with its quantum equal to the one given by Bekenstein (Phys Rev D 7:2333, 1973). We demonstrate that the quantization of entropy and area is a generic property of horizons which exists in a wide class of spacetimes admitting weakly isolated horizons. Our method based on the tunneling method also indicates that the entropy quantum of black hole horizons is closely related to Hawking temperature.

  17. Priority Questions and Horizon Scanning for Conservation: A Comparative Study

    PubMed Central

    Kark, Salit; Sutherland, William J.; Shanas, Uri; Klass, Keren; Achisar, Hila; Dayan, Tamar; Gavrieli, Yael; Justo-Hanani, Ronit; Mandelik, Yael; Orion, Nir; Pargament, David; Portman, Michelle; Reisman-Berman, Orna; Safriel, Uriel N.; Schaffer, Gad; Steiner, Noa; Tauber, Israel; Levin, Noam

    2016-01-01

    Several projects aimed at identifying priority issues for conservation with high relevance to policy have recently been completed in several countries. Two major types of projects have been undertaken, aimed at identifying (i) policy-relevant questions most imperative to conservation and (ii) horizon scanning topics, defined as emerging issues that are expected to have substantial implications for biodiversity conservation and policy in the future. Here, we provide the first overview of the outcomes of biodiversity and conservation-oriented projects recently completed around the world using this framework. We also include the results of the first questions and horizon scanning project completed for a Mediterranean country. Overall, the outcomes of the different projects undertaken (at the global scale, in the UK, US, Canada, Switzerland and in Israel) were strongly correlated in terms of the proportion of questions and/or horizon scanning topics selected when comparing different topic areas. However, some major differences were found across regions. There was large variation among regions in the percentage of proactive (i.e. action and response oriented) versus descriptive (non-response oriented) priority questions and in the emphasis given to socio-political issues. Substantial differences were also found when comparing outcomes of priority questions versus horizon scanning projects undertaken for the same region. For example, issues related to climate change, human demography and marine ecosystems received higher priority as horizon scanning topics, while ecosystem services were more emphasized as current priority questions. We suggest that future initiatives aimed at identifying priority conservation questions and horizon scanning topics should allow simultaneous identification of both current and future priority issues, as presented here for the first time. We propose that further emphasis on social-political issues should be explicitly integrated into future

  18. Priority Questions and Horizon Scanning for Conservation: A Comparative Study.

    PubMed

    Kark, Salit; Sutherland, William J; Shanas, Uri; Klass, Keren; Achisar, Hila; Dayan, Tamar; Gavrieli, Yael; Justo-Hanani, Ronit; Mandelik, Yael; Orion, Nir; Pargament, David; Portman, Michelle; Reisman-Berman, Orna; Safriel, Uriel N; Schaffer, Gad; Steiner, Noa; Tauber, Israel; Levin, Noam

    2016-01-01

    Several projects aimed at identifying priority issues for conservation with high relevance to policy have recently been completed in several countries. Two major types of projects have been undertaken, aimed at identifying (i) policy-relevant questions most imperative to conservation and (ii) horizon scanning topics, defined as emerging issues that are expected to have substantial implications for biodiversity conservation and policy in the future. Here, we provide the first overview of the outcomes of biodiversity and conservation-oriented projects recently completed around the world using this framework. We also include the results of the first questions and horizon scanning project completed for a Mediterranean country. Overall, the outcomes of the different projects undertaken (at the global scale, in the UK, US, Canada, Switzerland and in Israel) were strongly correlated in terms of the proportion of questions and/or horizon scanning topics selected when comparing different topic areas. However, some major differences were found across regions. There was large variation among regions in the percentage of proactive (i.e. action and response oriented) versus descriptive (non-response oriented) priority questions and in the emphasis given to socio-political issues. Substantial differences were also found when comparing outcomes of priority questions versus horizon scanning projects undertaken for the same region. For example, issues related to climate change, human demography and marine ecosystems received higher priority as horizon scanning topics, while ecosystem services were more emphasized as current priority questions. We suggest that future initiatives aimed at identifying priority conservation questions and horizon scanning topics should allow simultaneous identification of both current and future priority issues, as presented here for the first time. We propose that further emphasis on social-political issues should be explicitly integrated into future

  19. Reconstruction of soil moisture for the past 100 years in eastern Siberia by using δ13C of larch tree rings

    NASA Astrophysics Data System (ADS)

    Tei, Shunsuke; Sugimoto, Atsuko; Yonenobu, Hitoshi; Yamazaki, Takeshi; Maximov, Trofim C.

    2013-07-01

    stable carbon isotope ratio (δ13C) chronology for the past 100 years was developed from larch tree rings in eastern Siberia (near Yakutsk, 62°14'N, 129°37'E), to reconstruct past soil moisture water equivalent (SWE). Based on the correlation analyses between SWE and tree ring δ13C, we developed a linear regression model for SWE in the late growing period (LGP: 15 July to 31 August) using annual tree ring δ13C, which was calculated from the combination of latewood in a current year and earlywood in the following year, and then reconstructed SWE (LGP) for 1908-2007. Reconstructed SWE was compared with factors such as the output of the land surface model, annual precipitation, and Palmer Drought Severity Index for July. From the results, the reconstructed SWE appears reasonable and shows a large variation, including repeated occurrences of severe drought and an unprecedented high soil moisture event in 2006-2007 during the past 100 years. The reconstruction also captured a past documented record of severe drought in the 1940s. Despite the generally good performance of the reconstruction, by the 1930s the estimated SWE was higher than that expected from the annual precipitation. Tree ring width and δ13C were negatively correlated in most periods. However, the negative correlation was weaker for the period from 1919 to 1925, when relatively low air temperature was observed. This result suggests that the rate of photosynthesis, together with the degree of stomata opening, also affected the tree ring δ13C during cool periods.

  20. The NMC Horizon Report: 2014 Library Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Estrada, V.; Freeman, A.

    2014-01-01

    The internationally recognized "NMC Horizon Report" series and regional "NMC Technology Outlooks" are part of the NMC Horizon Project, a 12-year effort established in 2002 that annually identifies and describes emerging technologies likely to have a large impact over the coming five years in every sector of education around the…

  1. Reconceptualizing Knowledge at the Mathematical Horizon

    ERIC Educational Resources Information Center

    Zazkis, Rina; Mamolo, Ami

    2011-01-01

    This article extends the notion of "knowledge at the mathematical horizon" or "horizon knowledge" introduced by Ball and colleagues as a part of teachers' subject matter knowledge. Our focus is on teachers' mathematical knowledge beyond the school curriculum, that is, on mathematics learnt during undergraduate college or university studies. We…

  2. The Horizon Report: 2010 Museum Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Witchey, H.; Smith, R.; Levine, A.; Haywood, K.

    2010-01-01

    The internationally recognized series of "Horizon Reports" is part of the New Media Consortium's Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming five years on a variety of sectors around the globe. This volume, the "2010 Horizon…

  3. Expanding your horizons in science and mathematics

    NASA Technical Reports Server (NTRS)

    Palmer, Cynthia E. A.

    1995-01-01

    The purpose of the 'Expanding Your Horizons in Science and Mathematics' program is to interest young women in grades six through twelve in a variety of careers where mathematics and science are important. Progress in encouraging young women to take courses in mathematics, science, and technological subjects is discussed. Also included are adult, student, and organizational information packets used for 'Expanding Your Horizons' conferences.

  4. Horizon Report: 2010 K-12 Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Smith, R.; Levine, A.; Haywood, K.

    2010-01-01

    The "Horizon Report" series is the most visible outcome of the New Media Consortium's Horizon Project, an ongoing research effort established in 2002 that identifies and describes emerging technologies likely to have a large impact on teaching, learning, research, or creative expression within education around the globe. This volume, the "2010…

  5. The NMC Horizon Report: 2015 Museum Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Estrada, V.; Freeman, A.

    2015-01-01

    The internationally recognized series of "Horizon Reports" is part of the New Media Consortium's Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming years on a variety of sectors around the globe. This "2015 Horizon…

  6. High-frequency over-the-horizon radar and ionospheric backscatter studies in China

    NASA Astrophysics Data System (ADS)

    Li, Le-Wei

    1998-09-01

    China is one of the countries that employs high-frequency over-the-horizon radars for both military and civil applications. The first Chinese high-frequency over-the horizon backscatter radar was developed in the 1970s. This paper briefly introduces the first Chinese over-the-horizon backscatter radar system and reviews ionospheric backscatter and propagation studies in China. The paper discusses the motivation for establishing over-the-horizon radar systems in China, the experimental system, target recognition and detection,and estimation of over-the-horizon radar availability. Observations of aircraft, large-scale traveling ionospheric disturbances, and the effects of a remote nuclear explosion are also presented. Finally, the real-time Chinese ionosonde network and frequency predictions using backscatter ionograms are discussed.

  7. Estimation of the Horizon in Photographed Outdoor Scenes by Human and Machine

    PubMed Central

    Herdtweck, Christian; Wallraven, Christian

    2013-01-01

    We present three experiments on horizon estimation. In Experiment 1 we verify the human ability to estimate the horizon in static images from only visual input. Estimates are given without time constraints with emphasis on precision. The resulting estimates are used as baseline to evaluate horizon estimates from early visual processes. Stimuli are presented for only ms and then masked to purge visual short-term memory and enforcing estimates to rely on early processes, only. The high agreement between estimates and the lack of a training effect shows that enough information about viewpoint is extracted in the first few hundred milliseconds to make accurate horizon estimation possible. In Experiment 3 we investigate several strategies to estimate the horizon in the computer and compare human with machine “behavior” for different image manipulations and image scene types. PMID:24349073

  8. Spherically Symmetric Trapping Horizons, the Misner-Sharp Mass and Black Hole Evaporation

    NASA Astrophysics Data System (ADS)

    Nielsen, Alex B.; Yeom, Dong-Han

    We discuss some of the issues relating to information loss and black hole thermodynamics in the light of recent work on local black hole horizons. Understood in terms of pure states evolving into mixed states, the possibility of information loss in black holes is closely related to the global causal structure of space-time, as is the existence of event horizons. However, black holes need not be defined by event horizons, and in fact we argue that in order to have a fully unitary evolution for black holes, they should be defined in terms of something else, such as a trapping horizon. The Misner-Sharp mass in spherical symmetry shows very simply how trapping horizons can give rise to black hole thermodynamics, Hawking radiation and singularities. We show how the Misner-Sharp mass can also be used to give insights into the process of collapse and evaporation of locally defined black holes.

  9. Gravitational black hole hair from event horizon supertranslations

    NASA Astrophysics Data System (ADS)

    Averin, Artem; Dvali, Gia; Gomez, Cesar; Lüst, Dieter

    2016-06-01

    We discuss BMS supertranslations both at null-infinity BMS- and on the horizon {BMS}^{mathscr{H}} for the case of the Schwarzschild black hole. We show that both kinds of supertranslations lead to infinetly many gapless physical excitations. On this basis we construct a quotient algebra mathcal{A}equiv {BMS}^{mathscr{H}}/{BMS}- using suited superpositions of both kinds of transformations which cannot be compensated by an ordinary BMS-supertranslation and therefore are intrinsically due to the presence of an event horizon. We show that transformations in mathcal{A} are physical and generate gapless excitations on the horizon that can account for the gravitational hair as well as for the black hole entropy. We identify the physics of these modes as associated with Bogolioubov-Goldstone modes due to quantum criticality. Classically the number of these gapless modes is infinite. However, we show that due to quantum criticality the actual amount of information-carriers becomes finite and consistent with Bekenstein entropy. Although we only consider the case of Schwarzschild geometry, the arguments are extendable to arbitrary space-times containing event horizons.

  10. New Horizons' Extreme Close-Up of Pluto’s Surface (no audio)

    NASA Video Gallery

    This is the most detailed view of Pluto’s terrain you’ll see for a very long time. This mosaic strip – extending across the hemisphere that faced the New Horizons spacecraft as it flew past Pluto o...

  11. Quasilocal approach to general universal horizons

    NASA Astrophysics Data System (ADS)

    Maciel, Alan

    2016-05-01

    Theories of gravity with a preferred foliation usually display arbitrarily fast signal propagation, changing the black hole definition. A new inescapable barrier, the universal horizon, has been defined and many static and spherically symmetric examples have been studied in the literature. Here, we translate the usual definition of the universal horizon in terms of an optical scalar built with the preferred flow defined by the preferred spacetime foliation. The new expression has the advantages of being of quasilocal nature and independent of specific spacetime symmetries in order to be well defined. Therefore, we propose it as a definition for general quasilocal universal horizons. Using the new formalism, we show that there is no universal analog of cosmological horizons for Friedmann-Lemaître-Robertson-Walker models for any scale factor function, and we also state that quasilocal universal horizons are restricted to trapped regions of the spacetime. Using the evolution equation, we analyze the formation of universal horizons under a truncated Hořava-Lifshitz theory, in spherical symmetry, showing the existence of regions in parameter space where the universal horizon formation cannot be smooth from the center, under some physically reasonable assumptions. We conclude with our view on the next steps for the understanding of black holes in nonrelativistic gravity theories.

  12. A concrete anti-de Sitter black hole with dynamical horizon having toroidal cross-sections and its characteristics

    NASA Astrophysics Data System (ADS)

    Dadras, Pouria; Firouzjaee, J. T.; Mansouri, Reza

    2012-11-01

    We propose a special solution of Einstein equations in the general Vaidya form representing a dynamical black hole having horizon cross-sections with toroidal topology. The concrete model enables us to study for the first time dynamical horizons with toroidal topology, its area law, and the question of matter flux inside the horizon, without using a cut-and-paste technology to construct the solution.

  13. Production and decay of evolving horizons

    NASA Astrophysics Data System (ADS)

    Nielsen, Alex B.; Visser, Matt

    2006-07-01

    We consider a simple physical model for an evolving horizon that is strongly interacting with its environment, exchanging arbitrarily large quantities of matter with its environment in the form of both infalling material and outgoing Hawking radiation. We permit fluxes of both lightlike and timelike particles to cross the horizon, and ask how the horizon grows and shrinks in response to such flows. We place a premium on providing a clear and straightforward exposition with simple formulae. To be able to handle such a highly dynamical situation in a simple manner we make one significant physical restriction—that of spherical symmetry—and two technical mathematical restrictions: (1) we choose to slice the spacetime in such a way that the spacetime foliations (and hence the horizons) are always spherically symmetric. (2) Furthermore, we adopt Painlevé Gullstrand coordinates (which are well suited to the problem because they are nonsingular at the horizon) in order to simplify the relevant calculations. Of course physics results are ultimately independent of the choice of coordinates, but this particular coordinate system yields a clean physical interpretation of the relevant physics. We find particularly simple forms for surface gravity, and for the first and second law of black hole thermodynamics, in this general evolving horizon situation. Furthermore, we relate our results to Hawking's apparent horizon, Ashtekar and co-worker's isolated and dynamical horizons, and Hayward's trapping horizon. The evolving black hole model discussed here will be of interest, both from an astrophysical viewpoint in terms of discussing growing black holes and from a purely theoretical viewpoint in discussing black hole evaporation via Hawking radiation.

  14. New Horizons: Bridge to the Beginning - to Pluto and Beyond

    NASA Astrophysics Data System (ADS)

    Weir, H. M.; Hallau, K. G.; Seaton, P.; Beisser, K.; New Horizons Education; Public Outreach Team

    2010-12-01

    Launched on Jan. 19, 2006, NASA’s New Horizons mission to Pluto and the Kuiper Belt will help us understand worlds at the edge of our solar system by making the first reconnaissance of Pluto and Charon - a "double planet" and the last planet in our solar system to be visited by spacecraft. However, New Horizons’ closest approach to Pluto will not occur until July 14, 2015, and the majority of the craft's time over the next 5 years will be spent in "hibernation." The Education and Public Outreach (EPO) team, however, will not be hibernating as we wait for New Horizons to reach its destination. With three distinct tools-- Educator Fellows, online learning modules and a planetarium program--the team seeks to excite and engage teachers, students and the public with information about the journey to Pluto and beyond. In the past year, the specially selected educators who participate as New Horizons Educator Fellows have trained more than 1,000 teachers across the U.S. on the New Horizons mission and the science behind it. Thousands more students, parents, educators, and citizens have learned about New Horizons from the mission's scientists, engineers and outreach professionals. New Horizons Fellows also distribute another EPO tool: online learning modules. These classroom-ready learning modules consist of educator guides, student handouts, detailed activities, and potential adaptations for students with special needs or disabilities. Some also offer online interactives to convey complex and dynamic concepts. The modules are web-accessible for both students and teachers, and are aligned with relevant national standards. The third tool is a highly visual way to engage the general public and supplement educational programs: a planetarium program that highlights the New Horizons mission from launch to destination Pluto. This program focuses on the engineering design of the spacecraft, with a focus on the concept of the electromagnetic spectrum. In the unique environment

  15. Evolution of US maize (Zea mays L.) root architectural and anatomical phenes over the past 100 years corresponds to increased tolerance of nitrogen stress.

    PubMed

    York, Larry M; Galindo-Castañeda, Tania; Schussler, Jeffrey R; Lynch, Jonathan P

    2015-04-01

    Increasing the nitrogen use efficiency of maize is an important goal for food security and agricultural sustainability. In the past 100 years, maize breeding has focused on yield and above-ground phenes. Over this period, maize cultivation has changed from low fertilizer inputs and low population densities to intensive fertilization and dense populations. The authors hypothesized that through indirect selection the maize root system has evolved phenotypes suited to more intense competition for nitrogen. Sixteen maize varieties representing commercially successful lines over the past century were planted at two nitrogen levels and three planting densities. Root systems of the most recent material were 7 º more shallow, had one less nodal root per whorl, had double the distance from nodal root emergence to lateral branching, and had 14% more metaxylem vessels, but total mextaxylem vessel area remained unchanged because individual metaxylem vessels had 12% less area. Plasticity was also observed in cortical phenes such as aerenchyma, which increased at greater population densities. Simulation modelling with SimRoot demonstrated that even these relatively small changes in root architecture and anatomy could increase maize shoot growth by 16% in a high density and high nitrogen environment. The authors concluded that evolution of maize root phenotypes over the past century is consistent with increasing nitrogen use efficiency. Introgression of more contrasting root phene states into the germplasm of elite maize and determination of the functional utility of these phene states in multiple agronomic conditions could contribute to future yield gains. PMID:25795737

  16. Evolution of US maize (Zea mays L.) root architectural and anatomical phenes over the past 100 years corresponds to increased tolerance of nitrogen stress

    PubMed Central

    York, Larry M.; Galindo-Castañeda, Tania; Schussler, Jeffrey R.; Lynch, Jonathan P.

    2015-01-01

    Increasing the nitrogen use efficiency of maize is an important goal for food security and agricultural sustainability. In the past 100 years, maize breeding has focused on yield and above-ground phenes. Over this period, maize cultivation has changed from low fertilizer inputs and low population densities to intensive fertilization and dense populations. The authors hypothesized that through indirect selection the maize root system has evolved phenotypes suited to more intense competition for nitrogen. Sixteen maize varieties representing commercially successful lines over the past century were planted at two nitrogen levels and three planting densities. Root systems of the most recent material were 7 º more shallow, had one less nodal root per whorl, had double the distance from nodal root emergence to lateral branching, and had 14% more metaxylem vessels, but total mextaxylem vessel area remained unchanged because individual metaxylem vessels had 12% less area. Plasticity was also observed in cortical phenes such as aerenchyma, which increased at greater population densities. Simulation modelling with SimRoot demonstrated that even these relatively small changes in root architecture and anatomy could increase maize shoot growth by 16% in a high density and high nitrogen environment. The authors concluded that evolution of maize root phenotypes over the past century is consistent with increasing nitrogen use efficiency. Introgression of more contrasting root phene states into the germplasm of elite maize and determination of the functional utility of these phene states in multiple agronomic conditions could contribute to future yield gains. PMID:25795737

  17. Organochlorine pesticides (OCPs) in wetland soils under different land uses along a 100-year chronosequence of reclamation in a Chinese estuary

    NASA Astrophysics Data System (ADS)

    Bai, Junhong; Lu, Qiongqiong; Zhao, Qingqing; Wang, Junjing; Gao, Zhaoqin; Zhang, Guangliang

    2015-12-01

    Soil profiles were collected at a depth of 30 cm in ditch wetlands (DWs), riverine wetlands (RiWs) and reclaimed wetlands (ReWs) along a 100-year chronosequence of reclamation in the Pearl River Delta. In total, 16 OCPs were measured to investigate the effects of wetland reclamation and reclamation history on OCP levels. Our results showed that average ∑DDTs, HCB, MXC, and ∑OCPs were higher in surface soils of DWs compared to RiWs and ReWs. Both D30 and D20 soils contained the highest ∑OCP levels, followed by D40 and D100 soils; lower ∑OCP levels occurred in D10 soils. Higher ∑OCP levels were observed in the younger RiWs than in the older ones, and surface soils exhibited higher ∑OCP concentrations in the older ReWs compared with younger ReWs. The predominant percentages of γ-HCH in ∑HCHs (>42%) and aldrin in ∑DRINs (>46%) in most samples reflected the recent use of lindane and aldrin. The presence of dominant DDT isomers (p,p’-DDE and p,p’-DDD) indicated the historical input of DDT and significant aerobic degradation of the compound. Generally, DW soils had a higher ecotoxicological risk of OCPs than RiW and ReW soils, and the top 30 cm soils had higher ecotoxicological risks of HCHs than of DDTs.

  18. Organochlorine pesticides (OCPs) in wetland soils under different land uses along a 100-year chronosequence of reclamation in a Chinese estuary

    PubMed Central

    Bai, Junhong; Lu, Qiongqiong; Zhao, Qingqing; Wang, Junjing; Gao, Zhaoqin; Zhang, Guangliang

    2015-01-01

    Soil profiles were collected at a depth of 30 cm in ditch wetlands (DWs), riverine wetlands (RiWs) and reclaimed wetlands (ReWs) along a 100-year chronosequence of reclamation in the Pearl River Delta. In total, 16 OCPs were measured to investigate the effects of wetland reclamation and reclamation history on OCP levels. Our results showed that average ∑DDTs, HCB, MXC, and ∑OCPs were higher in surface soils of DWs compared to RiWs and ReWs. Both D30 and D20 soils contained the highest ∑OCP levels, followed by D40 and D100 soils; lower ∑OCP levels occurred in D10 soils. Higher ∑OCP levels were observed in the younger RiWs than in the older ones, and surface soils exhibited higher ∑OCP concentrations in the older ReWs compared with younger ReWs. The predominant percentages of γ-HCH in ∑HCHs (>42%) and aldrin in ∑DRINs (>46%) in most samples reflected the recent use of lindane and aldrin. The presence of dominant DDT isomers (p,p’-DDE and p,p’-DDD) indicated the historical input of DDT and significant aerobic degradation of the compound. Generally, DW soils had a higher ecotoxicological risk of OCPs than RiW and ReW soils, and the top 30 cm soils had higher ecotoxicological risks of HCHs than of DDTs. PMID:26633149

  19. Quantification of uncertainties in the 100-year flow at an ungaged site near a gaged station and its application in Georgia

    NASA Astrophysics Data System (ADS)

    Cho, Huidae; Bones, Emma

    2016-08-01

    The Federal Emergency Management Agency has introduced the concept of the "1-percent plus" flow to incorporate various uncertainties in estimation of the 100-year or 1-percent flow. However, to the best of the authors' knowledge, no clear directions for calculating the 1-percent plus flow have been defined in the literature. Although information about standard errors of estimation and prediction is provided along with the regression equations that are often used to estimate the 1-percent flow at ungaged sites, uncertainty estimation becomes more complicated when there is a nearby gaged station because regression flows and the peak flow estimate from a gage analysis should be weighted to compute the weighted estimate of the 1-percent flow. In this study, an equation for calculating the 1-percent plus flow at an ungaged site near a gaged station is analytically derived. Also, a detailed process is introduced for calculating the 1-percent plus flow for an ungaged site near a gaged station in Georgia as an example and a case study is performed. This study provides engineers and practitioners with a method that helps them better assess flood risks and develop mitigation plans accordingly.

  20. The beginnings of Orthopedic Surgery at the Mayo Clinic: A Review of the First Orthopedic Patients who Presented Over 100 Years Ago

    PubMed Central

    Camp, Christopher L.; Morrey, Bernard F; Trousdale, Robert T

    2016-01-01

    Background Formalized training in the specialty of orthopedic surgery began at the Mayo Clinic nearly 100 years ago, and treatment of patients with musculoskeletal injuries and disease began even earlier. A robust historical patient database provides the opportunity for review of the first recorded orthopedic cases at our institution, which date back to 1907. Methods The first 400 sequential medical charts of the Mayo Clinic’s patient record database were comprehensively reviewed in order to identify the first documented orthopedic cases. Results Of the first 400 patients reviewed, 15 (4%) received specific orthopedic diagnoses. All presented during a three week period in 1907, and they traveled from all over the region for evaluation. The diagnoses included skeletal tuberculosis (n=6), traumatic fracture (n=3), osteomyelitis (n=2), syphilitic pathologic fracture (n=1), syphilitic ostitis of the tibia and radius (n=1), painful flat foot (n=1), and Morton’s toe (n=1). Included with the records are patient demographics, diagnoses, symptoms, physical examination findings, radiograph reports, operative reports, and detailed drawings of symptomatology. Conclusion Although the technology and science has advanced since the early practice of orthopedic surgery that took place over a century ago, we consider ourselves to be merely an extension of those who established the field before us. Just as the past relies on the future for the continuation of what it began so many years ago, we rely on our founders for the groundwork that they laid in creating this field of surgical medicine PMID:27528834

  1. A 100-year record of changes in water renewal rate in Sermilik fjord and its influence on calving of Helheim glacier, southeast Greenland

    NASA Astrophysics Data System (ADS)

    Andresen, Camilla S.; Schmidt, Sabine; Seidenkrantz, Marit-Solveig; Straneo, Fiammetta; Grycel, Aleksandra; Hass, Christian H.; Henrik Kjær, Kurt; Nørgaard-Pedersen, Niels; Dyke, Laurence M.; Olsen, Jesper; Kuijpers, Antoon

    2014-08-01

    Here we present a 100 year long proxy record for the renewal rate of the subsurface ocean waters in Sermilik Fjord at the edge of Helheim Glacier, based on investigations of two sediment cores (ER11-24 and ER11-25) obtained from the head of the fjord. By calculating the mean sortable silt (SSbar) in current-sorted melt water plume sediments we find that episodes of increased water renewal rates lasting 3-5 years coincide with a positive North Atlantic Oscillation (NAO) index. This is not surprising as low pressure systems and northeasterly storms are observed more frequently along the east coast of Greenland during positive NAO years as a result of the northward shift in the North Atlantic storm track. Previous studies of sediment cores obtained from the mid-region of the fjord showed that Helheim Glacier destabilization coincides with a negative NAO index. Therefore we conclude that inter-annual variability in storm-induced flushing of Sermilik Fjord and thus the water renewal rate towards the glacier margin is not the controlling factor for inter-annual variability in Helheim Glacier destabilization. Such knowledge may have implications on predictive model studies of ice-ocean interactions and glacier behavior.

  2. On the thermodynamics of the cosmological apparent horizon

    NASA Astrophysics Data System (ADS)

    Pollock, M. D.

    2015-11-01

    It has been shown by Cai et al. that the apparent horizon of radius r0 in the cosmological Friedmann space-time emits radiation at the temperature T0 = 1/2π r0. Here, we derive this result from the Wheeler-DeWitt equation for the wave function of the Universe Ψ, starting from a classical gravitational Lagrangian L that contains a quadratic higher-derivative term R2 , the scalar component of which is non-tachyonic, by application of the horizon hypothesis and definition of the physical three-space on the time-slice dx0 = 0. We also extend our previous analysis of the Wheeler-DeWitt equation for the wave function Φ of the apparent horizon of the de Sitter space-time to include the case of a more general energy-momentum source, that generates an arbitrary Friedmann space-time, confirming the expression for T0 after application of the ADM formalism.

  3. Quantum Phase Transitions and Event Horizons:. Condensed Matter Analogies

    NASA Astrophysics Data System (ADS)

    Chapline, George

    2006-07-01

    Although it has been generally believed that classical general relativity is always correct for macroscopic length scales, certain predictions such as event horizons and closed time-like curves are inconsistent with ordinary quantum mechanics. It has recently been pointed out that the event horizon problem can be resolved if space-time undergoes a quantum phase transition as one approaches the surface where general relativity predicts that the redshift becomes infinite. Indeed a thought experiment involving a superfluid with a critical point makes such a suggestion appear plausible. Furthermore the behavior of space-time near an event horizon may resemble quantum phase transitions that have been observed in the laboratory. For example, the phenomenology of meta-magnetic quantum critical points in heavy fermion materials resembles the behavior expected, both in terms of time standing still and the behavior of quantum correlation functions. Martensitic transformations accompanied by non-adiabatic changes in the electronic wave function are also interesting in this connection.

  4. Horizon Entropy from Quantum Gravity Condensates

    NASA Astrophysics Data System (ADS)

    Oriti, Daniele; Pranzetti, Daniele; Sindoni, Lorenzo

    2016-05-01

    We construct condensate states encoding the continuum spherically symmetric quantum geometry of a horizon in full quantum gravity, i.e., without any classical symmetry reduction, in the group field theory formalism. Tracing over the bulk degrees of freedom, we show how the resulting reduced density matrix manifestly exhibits a holographic behavior. We derive a complete orthonormal basis of eigenstates for the reduced density matrix of the horizon and use it to compute the horizon entanglement entropy. By imposing consistency with the horizon boundary conditions and semiclassical thermodynamical properties, we recover the Bekenstein-Hawking entropy formula for any value of the Immirzi parameter. Our analysis supports the equivalence between the von Neumann (entanglement) entropy interpretation and the Boltzmann (statistical) one.

  5. Horizon Entropy from Quantum Gravity Condensates.

    PubMed

    Oriti, Daniele; Pranzetti, Daniele; Sindoni, Lorenzo

    2016-05-27

    We construct condensate states encoding the continuum spherically symmetric quantum geometry of a horizon in full quantum gravity, i.e., without any classical symmetry reduction, in the group field theory formalism. Tracing over the bulk degrees of freedom, we show how the resulting reduced density matrix manifestly exhibits a holographic behavior. We derive a complete orthonormal basis of eigenstates for the reduced density matrix of the horizon and use it to compute the horizon entanglement entropy. By imposing consistency with the horizon boundary conditions and semiclassical thermodynamical properties, we recover the Bekenstein-Hawking entropy formula for any value of the Immirzi parameter. Our analysis supports the equivalence between the von Neumann (entanglement) entropy interpretation and the Boltzmann (statistical) one. PMID:27284642

  6. Information Horizons in Complex Networks

    NASA Astrophysics Data System (ADS)

    Sneppen, Kim

    2005-03-01

    We investigate how the structure constrain specific communication in social-, man-made and biological networks. We find that human networks of governance and collaboration are predictable on teat-a-teat level, reflecting well defined pathways, but globally inefficient (1). In contrast, the Internet tends to have better overall communication abilities, more alternative pathways, and is therefore more robust. Between these extremes are the molecular network of living organisms. Further, for most real world networks we find that communication ability is favored by topology on small distances, but disfavored at larger distances (2,3,4). We discuss the topological implications in terms of modularity and the positioning of hubs in the networks (5,6). Finally we introduce some simple models which demonstarte how communication may shape the structure of in particular man made networks (7,8). 1) K. Sneppen, A. Trusina, M. Rosvall (2004). Hide and seek on complex networks [cond-mat/0407055] 2) M. Rosvall, A. Trusina, P. Minnhagen and K. Sneppen (2004). Networks and Cities: An Information Perspective [cond-mat/0407054]. In PRL. 3) A. Trusina, M. Rosvall, K. Sneppen (2004). Information Horizons in Networks. [cond-mat/0412064] 4) M. Rosvall, P. Minnhagen, K. Sneppen (2004). Navigating Networks with Limited Information. [cond-mat/0412051] 5) S. Maslov and K. Sneppen (2002). Specificity and stability in topology of protein networks Science 296, 910-913 [cond-mat/0205380]. 6) A. Trusina, S. Maslov, P. Minnhagen, K. Sneppen Hierarchy Measures in Complex Networks. Phys. Rev. Lett. 92, 178702 [cond-mat/0308339]. 7) M. Rosvall and K. Sneppen (2003). Modeling Dynamics of Information Networks. Phys. Rev. Lett. 91, 178701 [cond-mat/0308399]. 8) B-J. Kim, A. Trusina, P. Minnhagen, K. Sneppen (2003). Self Organized Scale-Free Networks from Merging and Regeneration. nlin.AO/0403006. In European Journal of Physics.

  7. Time of flight secondary ion mass spectrometry and high-resolution transmission electron microscopy/energy dispersive spectroscopy: a preliminary study of the distribution of Cu2+ and Cu2+/Pb2+ on a Bt horizon surfaces.

    PubMed

    Cerqueira, B; Vega, F A; Serra, C; Silva, L F O; Andrade, M L

    2011-11-15

    Relatively new techniques can help in determining the occurrence of mineral species and the distribution of contaminants on soil surfaces such as natural minerals and organic matter. The Bt horizon from an Endoleptic Luvisol was chosen because of its well-known sorption capability. The samples were contaminated with Cu(2+) and/or Pb(2+) and both sorption and desorption experiments were performed. The preferential distribution of the contaminant species ((63)Cu and (208)Pb) to the main soil components and their associations were studied together with the effectiveness of the surface sorption and desorption processes. The results obtained were compared with non-contaminated samples as well as with previous results obtained by different analytical techniques and advanced statistical analysis. Pb(2+) competes favorably for the sorption sites in this soil, mainly in oxides and the clay fraction. Cu(2+) and Pb(2+) were mainly associated with hematite, gibbsite, vermiculite and chlorite. This study will serve as a basis for further scientific research on the soil retention of heavy metals. New techniques such as spectroscopic imaging and transmission electron microscopy make it possible to check which soil components retain heavy metals, thereby contributing to propose effective measures for the remediation of contaminated soil. PMID:21920666

  8. Polychlorinated biphenyls (PCBs) in sediments/soils of different wetlands along 100-year coastal reclamation chronosequence in the Pearl River Estuary, China.

    PubMed

    Zhao, Qingqing; Bai, Junhong; Lu, Qiongqiong; Gao, Zhaoqin; Jia, Jia; Cui, Baoshan; Liu, Xinhui

    2016-06-01

    PCBs (polychlorinated biphenyls) were determined in sediment/soil profiles to a depth of 30 cm from three different wetlands (i.e., ditch wetlands, riparian wetlands and reclaimed wetlands) of the Pearl River Estuary to elucidate their levels, distribution and toxic risks along a 100-year chronosequence of reclamation. All detected PCB congeners and the total 15 PCBs (∑15 PCBs) decreased with depth along sediment/soil profiles in these three wetlands. The ∑15 PCBs concentrations ranged from 17.68 to 169.26 ng/g in surface sediments/soils. Generally, old wetlands tended to have higher PCB concentrations than younger ones. The dominant PCB congeners at all sampling sites were light PCB homologues (i.e., tetra-CBs and tri-CBs). According to the sediment quality guideline, the average PCB concentrations exceeded the threshold effects level (TEL, 21.6 ng/g) at most of the sampling sites, exhibiting possible adverse biological effects, which were dominantly caused by light PCB congeners. The total toxic equivalent (TEQ) concentrations of 10 dioxin-like PCBs (DL-PCBs) detected at all sampling sites ranged from 0.04 to 852.7 (10(-3) ng/g), mainly affected by PCB126. Only DL-PCB concentrations in ditch and riparian wetland sediments with 40-year reclamation histories (i.e., D40 and Ri40) exhibited moderate adverse biological effects according to SQGQ values. Principal component analysis indicated that PCBs in three wetland sediments/soils mainly originated from Aroclor 1016, 1242, and 1248. Correlation analysis showed that sediment/soil organic carbon content had a significant correlation with the concentrations of several PCB congeners (P < 0.05), whereas no significant correlations were observed between any PCBs congeners and grain size or aggregate content (P > 0.05). PMID:27038573

  9. Innate threat-sensitive foraging: black-tailed deer remain more fearful of wolf than of the less dangerous black bear even after 100 years of wolf absence.

    PubMed

    Chamaillé-Jammes, Simon; Malcuit, Hélène; Le Saout, Soizic; Martin, Jean-Louis

    2014-04-01

    Anti-predator behaviors often entail foraging costs, and thus prey response to predator cues should be adjusted to the level of risk (threat-sensitive foraging). Simultaneously dangerous predators (with high hunting success) should engender the evolution of innate predator recognition and appropriate anti-predator behaviors that are effective even upon the first encounter with the predator. The above leads to the prediction that prey might respond more strongly to cues of dangerous predators that are absent, than to cues of less dangerous predators that are actually present. In an applied context this would predict an immediate and stronger response of ungulates to the return of top predators such as wolves (Canis lupus) in many parts of Europe and North America than to current, less threatening, mesopredators. We investigated the existence of innate threat-sensitive foraging in black-tailed deer. We took advantage of a quasi-experimental situation where deer had not experienced wolf predation for ca. 100 years, and were only potentially exposed to black bears (Ursus americanus). We tested the response of deer to the urine of wolf (dangerous) and black bear (less dangerous). Our results support the hypothesis of innate threat-sensitive foraging with clear increased passive avoidance and olfactory investigation of cues from wolf, and surprisingly none to black bear. Prey which have previously evolved under high risk of predation by wolves may react strongly to the return of wolf cues in their environments thanks to innate responses retained during the period of predator absence, and this could be the source of far stronger non-consumptive effects of the predator guild than currently observed. PMID:24288079

  10. Climatic selection on genes and traits after a 100 year-old invasion: a critical look at the temperate-tropical clines in Drosophila melanogaster from eastern Australia.

    PubMed

    Hoffmann, Ary A; Weeks, Andrew R

    2007-02-01

    Drosophila melanogaster invaded Australia around 100 years ago, most likely through a northern invasion. The wide range of climatic conditions in eastern Australia across which D. melanogaster is now found provides an opportunity for researchers to identify traits and genes that are associated with climatic adaptation. Allozyme studies indicate clinal patterns for at least four loci including a strong linear cline in Adh and a non-linear cline in alpha-Gpdh. Inversion clines were initially established from cytological studies but have now been validated with larger sample sizes using molecular markers for breakpoints. Recent collections indicate that some genetic markers (Adh and In(3R)Payne) have changed over the last 20 years reflecting continuing evolution. Heritable clines have been established for quantitative traits including wing length/area, thorax length and cold and heat resistance. A cline in egg size independent of body size and a weak cline in competitive ability have also been established. Postulated clinal patterns for resistance to desiccation and starvation have not been supported by extensive sampling. Experiments under laboratory and semi-natural conditions have suggested selective factors generating clinal patterns, particularly for reproductive patterns over winter. Attempts are being made to link clinal variation in traits to specific genes using QTL analysis and the candidate locus approach, and to identify the genetic architecture of trait variation along the cline. This is proving difficult because of inversion polymorphisms that generate disequilibrium among genes. Substantial gaps still remain in linking clines to field selection and understanding the genetic and physiological basis of the adaptive shifts. However D. melanogaster populations in eastern Australia remain an excellent resource for understanding past and future evolutionary responses to climate change. PMID:16955331

  11. Fractionation, transfer, and ecological risks of heavy metals in riparian and ditch wetlands across a 100-year chronosequence of reclamation in an estuary of China.

    PubMed

    Xiao, Rong; Bai, Junhong; Lu, Qiongqiong; Zhao, Qingqing; Gao, Zhaoqin; Wen, Xiaojun; Liu, Xinhui

    2015-06-01

    The effect of reclamation on heavy metal concentrations and the ecological risks in ditch wetlands (DWs) and riparian wetlands (RWs) across a 100-year chronosequence in the Pearl River Estuary of China was investigated. Concentrations of 4 heavy metals (Cd, Cu, Pb, and Zn) in soil and plant samples, and sequential extracts of soil samples were determined, using inductively coupled plasma atomic absorption spectrometry. Results showed that heavy metal concentrations were higher in older DW soils than in the younger ones, and that the younger RW soils contained higher heavy metal concentrations compared to the older ones. Although the increasing tendency of heavy metal concentrations in soil was obvious after wetland reclamation, the metals Cu, Pb, and Zn exhibited low or no risks to the environment based on the risk assessment code (RAC). Cd, on the other hand, posed a medium or high risk. Cd, Pb, and Zn were mainly bound to Fe-Mn oxide, whereas most of Cu remained in the residual phase in both ditch and riparian wetland soils, and the residual proportions generally increased with depth. Bioconcentration and translocation factors for most of these four heavy metals significantly decreased in the DWs with older age (p<0.05), whereas they increased in the RWs with younger age (p<0.05). The DW soils contained higher concentrations of heavy metals in the organic fractions, whereas there were more carbonate and residual fractions in the RW soils. The non-bioavailable fractions of Cu and Zn, and the organic-bound Cd and Pb significantly inhibited plant growth. PMID:25723958

  12. Pluto Time

    NASA Video Gallery

    If you stood on Pluto at noon and looked around, the landscape would be illuminated about as brightly as on Earth soon after sunset. The team for NASA's New Horizons mission dubbed this "Pluto Time...

  13. Possible New Horizons Fundamental Contribution to Cosmology

    NASA Astrophysics Data System (ADS)

    Conn Henry, Richard; Murthy, Jayant

    2016-01-01

    The New Horizons (NH) spacecraft (S. Alan Stern, PI) is now past Pluto, and in our poster we explore the possibility of making observations, using the NH P-Alice ultraviolet spectrometer, of the cosmic diffuse ultraviolet background radiation, particularily at high northern and southern Galactic latitudes. In the paper, "The Mystery of the Cosmic Diffuse Ultraviolet Background Radiation," by Richard Conn Henry, Jayant Murthy, James Overduin, Joshua Tyler, ApJ, 798:14 (25pp), 2015 January 1, we demonstrated the existence of a second component of the diffuse far ultraviolet background radiation beyond that provided by dust-scattered starlight. The critical question is, does that second component (of unknown origin) extend shortward of the Lyman limit of 912 Å? If it does, then it seems likely that we have discovered the source of the reionization of the Universe that occurred some time after recombination. As things stand at the moment, there is no known source that has been demonstrated to be capable of performing the reionization: reionization that clearly did occur. Our current understanding of P-Alice suggests that it may well be capable of demonstrating the presence (or absence) of such ionizing cosmic diffuse radiation. At low Galactic latitudes, all such radiation would be totally erased by the presence, in large quantities, of interstellar neutral hydrogen; this will allow us to test the reality of any such flux that we may discover at higher Galactic latitudes.

  14. Possible Evidence for an Event Horizon in Cyg XR-1

    NASA Technical Reports Server (NTRS)

    Dolan, Joseph F.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The X-ray emitting component in the Cyg XR-1/HDE226868 system is a leading candidate for identification as a stellar-mass sized black hole. The positive identification of a black hole as predicted by general relativity requires the detection of an event horizon surrounding the point singularity. One signature of such an event horizon would be the existence of dying pulse trains emitted by material spiraling into the event horizon from the last stable orbit around the black hole. We observed the Cyg XR-1 system at three different epochs in a 1400 - 3000 A bandpass with 0.1 ms time resolution using the Hubble Space Telescope's High Speed Photometer. Repeated excursions of the detected flux by more than three standard deviations above the mean are present in the UV flux with FWHM 1 - 10 ms. If any of these excursions are pulses of radiation produced in the system (and not just stochastic variability associated with the Poisson distribution of detected photon arrival times), then this short a timescale requires that the pulses originate in the accretion disk around Cyg XR-1. Two series of pulses with characteristics similar to those expected from dying pulse trains were detected in three hours of observation.

  15. Investment horizon heterogeneity and wavelet: Overview and further research directions

    NASA Astrophysics Data System (ADS)

    Chakrabarty, Anindya; De, Anupam; Gunasekaran, Angappa; Dubey, Rameshwar

    2015-07-01

    Wavelet based multi-scale analysis of financial time series has attracted much attention, lately, from both the academia and practitioners from all around the world. The unceasing metamorphosis of the discipline of finance from its humble beginning as applied economics to the more sophisticated depiction as applied physics and applied psychology has revolutionized the way we perceive the market and its complexities. One such complexity is the presence of heterogeneous horizon agents in the market. In this context, we have performed a generous review of different aspects of horizon heterogeneity that has been successfully elucidated through the synergy between wavelet theory and finance. The evolution of wavelet has been succinctly delineated to bestow necessary information to the readers who are new to this field. The migration of wavelet into finance and its subsequent branching into different sub-divisions have been sketched. The pertinent literature on the impact of horizon heterogeneity on risk, asset pricing and inter-dependencies of the financial time series are explored. The significant contributions are collated and classified in accordance to their purpose and approach so that potential researcher and practitioners, interested in this subject, can be benefited. Future research possibilities in the direction of "agency cost mitigation" and "synergy between econophysics and behavioral finance in stock market forecasting" are also suggested in the paper.

  16. The Astrophysical Signatures of Black Holes: The Horizon, The ISCO, The Ergosphere and The Light Circle

    NASA Astrophysics Data System (ADS)

    Abramowicz, Marek A.

    Three advanced instruments planned for a near future ( LOFT, GRAVITY, THE EVENT HORIZON TELESCOPE) provide unprecedented angular and time resolutions, which allow to probe regions in the immediate vicinity of black holes. We may soon be able to search for the signatures of the super-strong gravity that is characteristic to black holes: the event horizon, the ergosphere, the innermost stable circular orbit (ISCO), and the photon circle. This review discusses a few fundamental problems concerning these theoretical concepts.

  17. The New Horizons Mission to Pluto and the Kuiper Belt

    NASA Astrophysics Data System (ADS)

    Weaver, H. A.; Stern, S. A.; New Horizons Science; Engineering Team

    New Horizons, which initiates the NASA New Frontiers program of mid-sized missions, will provide the first scientific reconnaissance of the Pluto-Charon system and is scheduled for launch in January 2006. An encounter with Jupiter at a flyby distance of ˜32-45 RJ about 13 months after launch provides a gravity boost for the spacecraft's journey to Pluto and practice for the Pluto encounter, in addition to providing an opportunity to perform a valuable set of scientific measurements within the jovian system. New Horizons carries a sophisticated suite of instruments to perform ultraviolet and infrared spectroscopy, panchromatic and color optical imaging, and charged particle and dust measurements, all within a spacecraft having a total mass of ˜465 kg and total power output of ˜210 W at the time of Pluto encounter in July 2015. The primary scientific objectives of the New Horizons are to characterize the global geology and morphology of Pluto and Charon, map the surface composition of Pluto and Charon, and characterize the neutral atmosphere and its escape rate, but many other important scientific objectives will be addressed as well. New Horizons has the capability to image Pluto with a resolution exceeding that provided by the Hubble Space Telescope for at least 90 days prior to closest approach at a distance of ˜10,000 km from the surface, at which time a resolution of ˜100 m will be achieved for selected regions near the terminator. After encounter, the spacecraft will pass through the shadows of both Pluto and Charon, which enables radio and ultraviolet occultation measurements of their atmospheres. If an extended mission phase is approved, the spacecraft will be re-targeted to encounter one or more Kuiper belt objects (KBOs), roughly 3 years after the Pluto encounter at a heliocentric distance of ˜42 AU. The scientific objectives for the KBO encounters are similar to those for the Pluto encounter.

  18. Aluminum solubility control in different horizons of a podzol

    SciTech Connect

    Zysset, M.; Blaser, P.; Luster, J.; Gehring, A.U.

    1999-10-01

    In the last two decades, the anthropogenically induced acceleration of forest soil acidification has been a topic of environmental concern. Aluminum extractability and solubility were investigated in detail in six horizons of a Typic Haplohumod (FAO:Haplic Podzol) from southern Switzerland. Pyrophosphate and oxalate extractions as well as successive acid leaching indicated that in the Ah, (AE), and Bh horizons reactive Al is mainly bound to soil organic matter, whereas in the Bs, BC1, and BC2 horizons it is of inorganic nature. In the latter three horizons, infrared (IR) spectroscopy and transmission electron microscopy (TEM) revealed the presence of imogolite. Batch equilibrium experiments at 20 C in the pH range of approximately 3.5 to 5.5 showed that the podzol profile can be divided into two parts of different Al solubility control. In the Ah and (AE) horizons, Al solubility was found to be controlled by complexation reactions to soil organic matter. Kinetic studies with samples of the Bh, Bs, BC1, and BC2 horizons showed that ion activity products with respect to both Al(OH){sub 3} and imogolite, (HO){sub 3}Al{sub 2}O{sub 3}SiOH, reached a constant value after reaction times of 16 d. For pH {gt}4.1, the compilation of all data revealed pAl + 0.5 pSi = 3.05 pH {minus} 7.04 (r{sup 2} = 0.99) and pAl = 2.87 pH {minus} 8.07 (r{sup 2} = 0.99). These data could be shown to be consistent with either Al solubility control by imogolite-type material (ITM) with a log *K{sub s}{sup 0} = 6.53 {+-} 0.09, which dissolves incongruently, or a simultaneous equilibrium with ITM and hydroxy-Al interlayers of clay minerals. For pH {lt} 4.1, data indicated solubility control by a 1:1 aluminosilicate, e.g., poorly crystalline kaolinite.

  19. 100 Years of benthic foraminiferal history on the inner Texas shelf inferred from fauna and stable isotopes: Preliminary results from two cores

    NASA Astrophysics Data System (ADS)

    Strauss, Josiah; Grossman, Ethan L.; Carlin, Joseph A.; Dellapenna, Timothy M.

    2012-04-01

    Coastal regions, such as the Texas-Louisiana shelf, are subject to seasonal hypoxia that strongly depends on the magnitude of freshwater discharge from local and regional river systems. We have determined benthic foraminiferal fauna and isotopic compositions in two 210Pb dated box cores (BR4 and BR5) to examine the evidence for nearshore hypoxia and freshwater discharge on the Texas shelf during the last 100 years. The 210Pb chronologies of both cores reveal sedimentation rates of 0.2 and 0.1 cm yr-1, translating to ˜60 and ˜90 year records. The fauna of both cores were almost exclusively composed of Ammonia parkinsoniana and Elphidium excavatum, indicating euryhaline ambient waters. The Ammonia-Elphidium (A-E) index, a qualitative measure of low oxygen conditions, shows an increase from values between 20 and 50 to near 100 in both cores, suggesting low oxygen conditions between 1960 and the core top. Between 1950 and 1960 (9-10 cm), low A-E values in BR4 coincide with high δ18O and δ13C values greater than 0‰ and -1‰ respectively. This event corresponds to severe drought (the Texas Drought of Record) over the Brazos River drainage basin and considerably reduced river discharge from 1948 to 1957. High A-E values prior to this event imply low-oxygen conditions were prevalent prior to anthropogenic exacerbation of Louisiana shelf hypoxia and at least since the dredging of a new Brazos River delta in 1929. Elphidium excavatum δ13C values are very low (-4‰) and indicative of significant vital effect. The δ13C values of A. parkinsoniana average -3‰ and exhibit little variability, most likely reflecting pore waters influenced by aerobic and anaerobic respiration. The association of lowered Brazos River discharge with more oxygenated shelf bottom waters suggests Brazos River discharge and shelf hypoxia are linked, but the influence of Mississippi-Atchafalaya discharge can also contribute to shelf stratification.

  20. Star-Paths, Stones and Horizon Astronomy

    NASA Astrophysics Data System (ADS)

    Brady, Bernadette

    2015-05-01

    Archaeoastronomers tend to approach ancient monuments focusing on the landscape and the horizon calendar events of sun and moon and, due to problems with precession, generally ignore the movement of the stars. However, locating the position of solar calendar points on the horizon can have other uses apart from calendar and/or cosmological purposes. This paper firstly suggests that the stars do not need to be ignored. By considering the evidence of the Phaenomena, a sky poem by Aratus of Soli, a third century BC Greek poet, and his use of second millennium BC star lore fragments, this paper argues that the stars were a part of the knowledge of horizon astronomy. Aratus' poem implied that the horizon astronomy of the late Neolithic and Bronze Age periods included knowledge of star-paths or 'linear constellations' that were defined by particular horizon calendar events and other azimuths. Knowledge of such star-paths would have enabled navigation and orientation, and by using permanent markers, constructed or natural, to define these paths, they were immune to precession as the stones could redefine a star-path for a future generation. Finally the paper presents other possible intentions behind the diverse orientation of passage tombs and some megalithic sites.

  1. Flying by Ear: Blind Flight with a Music-Based Artificial Horizon

    NASA Technical Reports Server (NTRS)

    Simpson, Brian D.; Brungart, Douglas S.; Dallman, Ronald C.; Yasky, Richard J., Jr.; Romigh, Griffin

    2008-01-01

    Two experiments were conducted in actual flight operations to evaluate an audio artificial horizon display that imposed aircraft attitude information on pilot-selected music. The first experiment examined a pilot's ability to identify, with vision obscured, a change in aircraft roll or pitch, with and without the audio artificial horizon display. The results suggest that the audio horizon display improves the accuracy of attitude identification overall, but differentially affects response time across conditions. In the second experiment, subject pilots performed recoveries from displaced aircraft attitudes using either standard visual instruments, or, with vision obscured, the audio artificial horizon display. The results suggest that subjects were able to maneuver the aircraft to within its safety envelope. Overall, pilots were able to benefit from the display, suggesting that such a display could help to improve overall safety in general aviation.

  2. The Event Horizon Telescope: New Developments and Results

    NASA Astrophysics Data System (ADS)

    Johnson, Michael D.; Doeleman, Sheperd S.; Event Horizon Telescope Collaboration

    2015-08-01

    A convergence of high-bandwidth radio instrumentation and global submillimeter facilities is enabling assembly of the Event Horizon Telescope (EHT): a short-wavelength Very-Long-Baseline Interferometry array capable of observing the nearest supermassive black holes with Schwarzschild-radius resolution. Initial observations with the EHT have revealed event-horizon-scale structure in Sgr A*, the 4 million solar mass black hole at the Galactic center, and in the much more luminous and massive black hole at the center of the giant elliptical galaxy M87. The past year has witnessed rapid expansion of the array, including first light and successful interferometric fringes for new receivers at the Large Millimeter Telescope in Mexico and the South Pole Telescope, as well as fringes to the ALMA phased array. Concurrent instrumental developments also allow 2 GHz observing bandwidth with dual polarization in the 2015 observing campaign. Together, these advances will yield an unprecedented combination of sensitivity and resolution, with excellent prospects for imaging strong general relativistic signatures, detecting horizon-scale magnetic field structures through full polarization observations, and time-resolving dynamical activity near a black hole. I will briefly review the recent developments and technical timeline for completing the EHT and will present new results from our 2013 observing campaign.

  3. The Orbits and Masses of Pluto's Satellites after New Horizons

    NASA Astrophysics Data System (ADS)

    Jacobson, Robert A.; Brozovic, Marina; Buie, Marc; Porter, Simon; Showalter, Mark; Spencer, John; Stern, S. Alan; Weaver, Harold; Young, Leslie; Ennico, Kimberly; Olkin, Cathy

    2015-11-01

    Brozović et al. (2015 Icarus 246, 317) reported on Pluto's mass and the masses and numerically integrated orbits of Pluto's satellites, Charon, Nix, Hydra, Kerberos, and Styx. These were determined via a fit to an extensive set of astrometric, mutual event, and stellar occultation observations over the time interval April 1965 to July 2012. The data set contained the Hubble Space Telescope (HST) observations of Charon relative to Pluto that were corrected for the Pluto center-of-figure center-of-light offset due to the Pluto albedo variations (Buie et al. 2012 AJ 144, 15). Also included were all of the available HST observations of Nix, Hydra, Kerberos, and Styx. For the New Horizons encounter with the Pluto system, the initial satellite ephemerides (PLU043) and the initial planet and satellite masses were taken from the Brozović et al. analysis. During the New Horizons approach, the ephemerides and masses were periodically updated along with the spacecraft trajectory by the New Horizons navigation team using imaging of the planet and satellites against the stellar background. In this work, we report on our post-flyby analysis of the masses and satellite orbits derived from a combination of the original PLU043 data set, the New Horizions imaging data, and HST observations acquired after 2012.

  4. On horizons and wormholes in k-essence theories

    NASA Astrophysics Data System (ADS)

    Bronnikov, K. A.; Fabris, J. C.; Rodrigues, Denis C.

    2016-01-01

    We study the properties of possible static, spherically symmetric configurations in k-essence theories with the Lagrangian functions of the form $F(X)$, $X \\equiv \\phi_{,\\alpha} \\phi^{,\\alpha}$. A no-go theorem has been proved, claiming that a possible black-hole-like Killing horizon of finite radius cannot exist if the function $F(X)$ is required to have a finite derivative $dF/dX$. Two exact solutions are obtained for special cases of k-essence: one for $F(X) =F_0 X^{1/3}$, another for $F(X) = F_0 |X|^{1/2} - 2 \\Lambda$, where $F_0$ and $\\Lambda$ are constants. Both solutions contain horizons, are not asymptotically flat, and provide illustrations for the obtained no-go theorem. The first solution may be interpreted as describing a black hole in an asymptotically singular space-time, while in the second solution two horizons of infinite area are connected by a wormhole.

  5. Summary and status of the Horizons ephemeris system

    NASA Astrophysics Data System (ADS)

    Giorgini, J.

    2011-10-01

    Since 1996, the Horizons system has provided searchable access to JPL ephemerides for all known solar system bodies, several dozen spacecraft, planetary system barycenters, and some libration points. Responding to 18 400 000 requests from 300 000 unique addresses, the system has recently averaged 420 000 ephemeris requests per month. Horizons is accessed and automated using three interfaces: interactive telnet, web-browser form, and e-mail command-file. Asteroid and comet ephemerides are numerically integrated from JPL's database of initial conditions. This small-body database is updated hourly by a separate process as new measurements and discoveries are reported by the Minor Planet Center and automatically incorporated into new JPL orbit solutions. Ephemerides for other objects are derived by interpolating previously developed solutions whose trajectories have been represented in a file. For asteroids and comets, such files may be dynamically created and transferred to users, effectively recording integrator output. These small-body SPK files may then be interpolated by user software to reproduce the trajectory without duplicating the numerically integrated n-body dynamical model or PPN equations of motion. Other Horizons output is numerical and in the form of plain-text observer, vector, osculating element, or close-approach tables, typically expected be read by other software as input. About one hundred quantities can be requested in various time-scales and coordinate systems. For JPL small-body solutions, this includes statistical uncertainties derived from measurement covariance and state transition matrices. With the exception of some natural satellites, Horizons is consistent with DE405/DE406, the IAU 1976 constants, ITRF93, and IAU2009 rotational models.

  6. Holography of 3D flat cosmological horizons.

    PubMed

    Bagchi, Arjun; Detournay, Stéphane; Fareghbal, Reza; Simón, Joan

    2013-04-01

    We provide a first derivation of the Bekenstein-Hawking entropy of 3D flat cosmological horizons in terms of the counting of states in a dual field theory. These horizons appear in the flat limit of nonextremal rotating Banados-Teitleboim-Zanelli black holes and are remnants of the inner horizons. They also satisfy the first law of thermodynamics. We study flat holography as a limit of AdS(3)/CFT(2) to semiclassically compute the density of states in the dual theory, which is given by a contraction of a 2D conformal field theory, exactly reproducing the bulk entropy in the limit of large charges. We comment on how the dual theory reproduces the bulk first law and how cosmological bulk excitations are matched with boundary quantum numbers. PMID:25166977

  7. East Rim of Endeavour Crater on Horizon

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site]

    A high point on the distant eastern rim of Endeavour Crater is visible on the horizon in this image taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity on March 8, 2009, during the 1,821st Martian day, or sol, of the rover's mission on Mars.

    That portion of Endeavour's rim is about 34 kilometers (21 miles) away from Opportunity's position west of the crater when the image was taken. The width of the image covers approximately one degree of the horizon.

  8. North Rim of Endeavour Crater on Horizon

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site]

    A northern portion of the rim of Endeavour Crater is visible on the horizon of this image taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity on March 7, 2009, during the 1,820st Martian day, or sol, of the rover's mission on Mars.

    That portion of Endeavour's rim is about 20 kilometers (12 miles) away from Opportunity's position west of the crater when the image was taken. The width of the image covers approximately one degree of the horizon.

  9. Expanding your horizons in science and mathematics

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Through the presentation of its Expanding Your Horizons in Science and Mathematics career education conferences for secondary school young women, the Math/Science Network continues its efforts to remove the educational, psychological, and cultural barriers which prevent women from entering math-and science-based careers. The Expanding Your Horizons conferences were presented on 77 college, university and high school campuses across the United States. This year, these unique one day conferences reached 15,500 students, 3,000 parents and educators, and involved 3,000 career women who volunteered their services as conference planners, workshop leaders, speakers, and role models.

  10. Hair-brane ideas on the horizon

    NASA Astrophysics Data System (ADS)

    Martinec, Emil J.; Niehoff, Ben E.

    2015-11-01

    We continue an examination of the microstate geometries program begun in arXiv:1409.6017, focussing on the role of branes that wrap the cycles which degenerate when a throat in the geometry deepens and a horizon forms. An associated quiver quantum mechanical model of minimally wrapped branes exhibits a non-negligible fraction of the gravitational entropy, which scales correctly as a function of the charges. The results suggest a picture of AdS3/CFT2 duality wherein the long string that accounts for BTZ black hole entropy in the CFT description, can also be seen to inhabit the horizon of BPS black holes on the gravity side.

  11. Horizons and plane waves: A review

    SciTech Connect

    Hubeny, Veronika E.; Rangamani, Mukund

    2003-11-06

    We review the attempts to construct black hole/string solutions in asymptotically plane wave spacetimes. First, we demonstrate that geometries admitting a covariantly constant null Killing vector cannot admit event horizons, which implies that pp-waves can't describe black holes. However, relaxing the symmetry requirements allows us to generate solutions which do possess regular event horizons while retaining the requisite asymptotic properties. In particular, we present two solution generating techniques and use them to construct asymptotically plane wave black string/brane geometries.

  12. Evidence for a sedimentary siloxane horizon

    SciTech Connect

    Pellenbarg, R.E.; Tevault, D.E.

    1986-07-01

    Selected samples from two Puget Sound sediment cores have been analyzed for poly(organo)siloxanes(silicones). One core was 60 years old at 30-cm depth (ages by lead-210 dating) and showed no evidence for silicones there. The second, 15 years old at depth, exhibited silicones at depth. Clearly shown is evidence for a siloxane horizon in theses two cores, with the presence of the horizon directly related to the fact that silicones have been in widespread use only since World War II. All samples were analyzed by solvent extraction and diffuse reflectance Fourier transform infrared spectrometry. 10 references, 2 figures, 1 table.

  13. Aerosol physical properties from satellite horizon inversion

    NASA Technical Reports Server (NTRS)

    Gray, C. R.; Malchow, H. L.; Merritt, D. C.; Var, R. E.; Whitney, C. K.

    1973-01-01

    The feasibility is investigated of determining the physical properties of aerosols globally in the altitude region of 10 to 100 km from a satellite horizon scanning experiment. The investigation utilizes a horizon inversion technique previously developed and extended. Aerosol physical properties such as number density, size distribution, and the real and imaginary components of the index of refraction are demonstrated to be invertible in the aerosol size ranges (0.01-0.1 microns), (0.1-1.0 microns), (1.0-10 microns). Extensions of previously developed radiative transfer models and recursive inversion algorithms are displayed.

  14. Hair from the Isolated Horizon Perspective

    NASA Astrophysics Data System (ADS)

    Corichi, A.; Sudarsky, D.

    2002-12-01

    The recently introduced Isolated Horizons (IH) formalism has become a powerful tool for realistic black hole physics. In particular, it generalizes the zeroth and first laws of black hole mechanics in terms of quasi-local quantities and serves as a starting point for quantum entropy calculations. In this note we consider theories which admit hair, and analyze some new results that the IH provides, when considering solitons and stationary solutions. Furthermore, the IH formalism allows to state uniqueness conjectures (i.e. horizon 'no-hair conjectures') for the existence of solutions.

  15. Expanding Horizons of Health Cares

    MedlinePlus

    ... about who uses CAM, how it can alleviate low back pain, how an ancient Chinese treatment works for some ... Progress / Acupuncture From Ancient Practice to Modern Science / Low Back Pain and CAM / Time to Talk / Quiz on Complementary ...

  16. The New Horizons Radio Science Experiment (REX)

    NASA Astrophysics Data System (ADS)

    Tyler, G. L.; Linscott, I. R.; Bird, M. K.; Hinson, D. P.; Strobel, D. F.; Pätzold, M.; Summers, M. E.; Sivaramakrishnan, K.

    2008-10-01

    The New Horizons (NH) Radio Science Experiment, REX, is designed to determine the atmospheric state at the surface of Pluto and in the lowest few scale heights. Expected absolute accuracies in n, p, and T at the surface are 4ṡ1019 m-3, 0.1 Pa, and 3 K, respectively, obtained by radio occultation of a 4.2 cm- λ signal transmitted from Earth at 10-30 kW and received at the NH spacecraft. The threshold for ionospheric observations is roughly 2ṡ109 e- m-3. Radio occultation experiments are planned for both Pluto and Charon, but the level of accuracy for the neutral gas is expected to be useful at Pluto only. REX will also measure the nightside 4.2 cm- λ thermal emission from Pluto and Charon during the time NH is occulted. At Pluto, the thermal scan provides about five half-beams across the disk; at Charon, only disk integrated values can be obtained. A combination of two-way tracking and occultation signals will determine the Pluto system mass to about 0.01 percent, and improve the Pluto-Charon mass ratio. REX flight equipment augments the NH radio transceiver used for spacecraft communications and tracking. Implementation of REX required realization of a new CIC-SCIC signal processing algorithm; the REX hardware implementation requires 1.6 W, and has mass of 160 g in 520 cm3. Commissioning tests conducted after NH launch demonstrate that the REX system is operating as expected.

  17. Do Forest Age and Soil Depth Affect Carbon and Nitrogen Adsorption in Mineral Horizons?

    NASA Astrophysics Data System (ADS)

    Spina, P. G.; Lovett, G. M.; Fuss, C. B.; Goodale, C. L.; Lang, A.; Fahey, T.

    2015-12-01

    Mineral soils retain large amounts of organic matter through sorption on the surfaces of mineral soils, the largest pools of carbon (C) and nitrogen (N) in the forests of the northeastern U.S. In addition to determining organic matter storage, adsorption and desorption processes are important controllers of runoff chemistry. We are studying adsorption dynamics of mineral soils collected from a chronosequence of hardwood forest sites in the White Mountains, NH to determine how soils vary in their DOM adsorption capacities as a function of effective C and N saturation. We hypothesize that forest age determines proximity to saturation because young forests may need to mine soil organic matter (SOM) in mineral soils to obtain nitrogen to meet growth demands, while the soils of older forests have had time to reaccumulate SOM, eventually reaching C and N saturation. Consequently, we expect adsorption capacities to first increase with forest age in young forests, as the trees mine C and N from mineral surfaces. They will then decrease with forest age in older forests as mining slows and C and N begin to re-accumulate. Batch experiments were conducted with mineral soil samples and dilutions of forest floor leachate. However, preliminary results from a mature forest site (about 100 years old), which we predicted to be a low point of C and N saturation from decades of mining, contradict expectations. Dissolved organic carbon (DOC) adsorption in its shallow mineral soil layers (0-3 cm below E or A horizons) are lower than younger sites ranging from 20 to about 40 years old. In addition to forest age, soil depths also affect N retention dynamics in forest soils. We hypothesized that deeper mineral soils might have greater adsorption capacities due to the fact that they are exposed to less DOC and DON leaching from organic layers and therefore less saturated. Results from the same mature forest site confirm this. Soils from 3-10 cm depth have more potential to adsorb DOC and

  18. Contemporaneous Mid-UV Spectral Coverage of Pluto and Charon Coincident With the New Horizons Encounter

    NASA Astrophysics Data System (ADS)

    Schindhelm, Eric

    2014-10-01

    The New Horizons spacecraft will perform the first-ever, and the only planned flyby of the Pluto System, in July 2015. It will observe Pluto and its moons from Far-Ultraviolet (FUV) to radio wavelengths. However, between 1870 and 4200 Angstroms there is no spectral coverage aboard New Horizons. The Mid-Ultraviolet (MUV, 2000 - 3000 Angstroms), which cannot be observed from the ground, contains numerous useful indicators of surface and atmospheric composition that can provide additional constraints about Pluto. Since Pluto's MUV spectrum is known to change over time, it is scientifically important to capture such data at the unique New Horizons encounter epoch. We propose here a focused, 2-orbit STIS G230L observation of Pluto at the same sub-Earth longitude where New Horizons will obtain its best FUV spectra during its closest approach to Pluto. We note that these HST observations need not occur on the same day as the New Horizons encounter, only during the same observing season. In two orbits, STIS yields higher-SNR spectra of Pluto than have ever been obtained to date in the MUV. This will bridge the gap in New Horizons' spectral coverage, placing the FUV spectra in context with longer wavelength data and contributing new information to augment the New Horizons results with those from HST. Our main science objective is MUV spectroscopy of Pluto, however if scheduling allows for the correct roll angle to also capture Charon in the STIS 52"x2" slit, MUV surface reflectance spectra of Charon would also complement New Horizons FUV data.

  19. Near-horizon circular orbits and extremal limit for dirty rotating black holes

    NASA Astrophysics Data System (ADS)

    Zaslavskii, O. B.

    2015-08-01

    We consider generic rotating axially symmetric "dirty" (surrounded by matter) black holes. Near-horizon circular equatorial orbits are examined in two different cases of near-extremal (small surface gravity κ ) and exactly extremal black holes. This has a number of qualitative distinctions. In the first case, it is shown that such orbits can lie as close to the horizon as one wishes on suitably chosen slices of space-time when κ →0 . This generalizes the observation of T. Jacobson [Classical Quantum Gravity 28, 187001 (2011), 10.1088/0264-9381/28/18/187001] made for the Kerr metric. If a black hole is extremal (κ =0 ), circular on-horizon orbits are impossible for massive particles but, in general, are possible in its vicinity. The corresponding black hole parameters determine also the rate with which a fine-tuned particle on the noncircular near-horizon orbit asymptotically approaches the horizon. Properties of orbits under discussion are also related to the Bañados-Silk-West effect of high energy collisions near black holes. Impossibility of the on-horizon orbits in question is manifestation of kinematic censorship that forbids infinite energies in collisions.

  20. Space Launch Initiative: New Capabilities ... New Horizons

    NASA Technical Reports Server (NTRS)

    Dumbacher, Daniel L.

    2002-01-01

    This paper presents NASA's Space Launch Initiative (SLI) with new capabilities and new horizons. The topics include: 1) Integrated Space Transportation Plan; 2) SLI: The Work of an Nation; 3) SLI Goals and Status; 4) Composites and Materials; and 5) SLI & DoD/USAF Collaboration. This paper is presented in viewgraph form.

  1. Space Launch Initiative: New Capabilities - New Horizons

    NASA Technical Reports Server (NTRS)

    Dumbacher, Daniel; Smith, Dennis E. (Technical Monitor)

    2002-01-01

    This paper presents NASA's Space Launch Initiative (SLI) with new capabilities and new horizons. The topics include: 1) Integrated Space Transportation Plan; 2) SLI: The Work of a Nation; 3) SLI Goals and Status; 4) Composites and Materials; and 5) SLI and DOD/USAF Collaboration. This paper is in viewgraph form.

  2. Automatic star-horizon angle measurement system

    NASA Technical Reports Server (NTRS)

    Koerber, K.; Koso, D. A.; Nardella, P. C.

    1969-01-01

    Automatic star horizontal angle measuring aid for general navigational use incorporates an Apollo type sextant. The eyepiece of the sextant is replaced with two light detectors and appropriate circuitry. The device automatically determines the angle between a navigational star and a unique point on the earths horizon as seen on a spacecraft.

  3. The NMC Horizon Report: 2013 Museum Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Freeman, A.

    2013-01-01

    The "NMC Horizon Report: 2013 Museum Edition," is a co-production with the Marcus Institute for Digital Education in the Arts (MIDEA), and examines six emerging technologies for their potential impact on and use in education and interpretation within the museum environment: BYOD (Bring Your Own Device), crowdsourcing, electronic…

  4. Gateway's Horizon: A Center of Excellence

    ERIC Educational Resources Information Center

    Herring, Jayne; Colony, Lee

    2007-01-01

    This article describes Gateway Technical College's Horizon Center for Transportation Technology, located in Kenosha, Wisconsin, which was the product of collaboration with business and industry, community support and a U.S. Department of Labor (DOL) grant. The center, which opened this fall, is a prime example of a sustainable community…

  5. New Concepts on the Educational Horizon.

    ERIC Educational Resources Information Center

    Gilchrist, Robert S.; Mitchell, Edna

    Four dimensions in education provide a basis for discussing future horizons: (1) curriculum development, (2) teacher education, (3) administration and organization, and (4) research and development. These areas are interdependent, and one cannot be improved or changed without affecting the other areas. Within these areas, some of the broad changes…

  6. New Horizons in Mathematics and Science Education.

    ERIC Educational Resources Information Center

    Thorson, Annette, Ed.

    2001-01-01

    This journal, intended for classroom teachers, provides a collection of essays organized around the theme of new horizons in mathematics and science education as well as a guide to instructional materials related to the theme. Topics addressed in the essays include digital libraries, the future of science curricula, integrated curricula, and…

  7. Agriculture’s Ethical Horizon, book review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Roughly 6.5 billion people inhabit the earth, but over 1 billion people regularly go hungry. This food shortfall poses an ethical dilemma for agriculture, and Agriculture's Ethical Horizon grapples with this dilemma. It argues that agricultural productivity has been the quintessential value of agr...

  8. Vegetarianism. New Horizons in Nutrition.

    ERIC Educational Resources Information Center

    Arnold, Justine; Grogan, Jane, Ed.

    This instructional handbook is one of a series of ten packets designed to form a comprehensive course in nutrition for secondary students. This unit examines the vegetarian diet as a viable alternative, and at the same time, it introduces the topics of protein and vitamin B12. It contains a page of teaching suggestions, a pre-test for the…

  9. Prediction horizon effects on stochastic modelling hints for neural networks

    SciTech Connect

    Drossu, R.; Obradovic, Z.

    1995-12-31

    The objective of this paper is to investigate the relationship between stochastic models and neural network (NN) approaches to time series modelling. Experiments on a complex real life prediction problem (entertainment video traffic) indicate that prior knowledge can be obtained through stochastic analysis both with respect to an appropriate NN architecture as well as to an appropriate sampling rate, in the case of a prediction horizon larger than one. An improvement of the obtained NN predictor is also proposed through a bias removal post-processing, resulting in much better performance than the best stochastic model.

  10. The Pluto System As Seen By New Horizons Spacecraft

    NASA Video Gallery

    The Pluto system as NASA’s New Horizons spacecraft saw it in July 2015. This animation, made with real images taken by New Horizons, begins with Pluto flying in for its close-up on July 14; we then...

  11. SETAC launches global horizon scanning/research prioritization project

    EPA Science Inventory

    The SETAC World Council is pleased to announce the initiation of a Global Horizon Scanning and Prioritization Project aimed at identifying geographically specific research needs to address stressor impacts on environmental quality. In recent years, horizon scanning and research ...

  12. New horizons in osteoporosis therapies.

    PubMed

    Harsløf, Torben; Langdahl, Bente L

    2016-06-01

    Efficient therapies are available for the treatment of osteoporosis, however, there are still unmet needs. Anti-resorptive therapies only increase bone mineral density to a certain extent and reduce the risk of non-vertebral fractures by 20%, only one anabolic option is available-the effect of which levels off over time, and the evidence for combination therapy targeting both resorption and formation is limited. The current review will focus on emerging treatments of osteoporosis with the potential of enhanced anabolic effects (romosozumab and abaloparatide) or uncoupling of resorption and formation (odanacatib and romosozumab) as well as the effect of combination therapy. PMID:26989807

  13. The dogger reef horizons of the Moroccan Central High Atlas: New data on their development

    NASA Astrophysics Data System (ADS)

    Ait Addi, Abdellah

    2006-06-01

    In the Central High Atlas, N of Errachidia, three major reef horizons in the Bajocian carbonate series of the Atlasic Basin were studied recently. The results of the study are based on fieldwork with an emphasis on stratigraphy, morphology and sedimentary patterns of detailed field sections. The lower reef horizon is composed of smaller build-ups which developed during the Aalenian-Lower Bajocian interval. At that time the depositional environment favored the production of both basinal and platform facies. This reef horizon is located only on the southern platform rim. Its development within the trough was controlled by synsedimentary block tilting, triggered by rifting, which was related to an ancient fracture zones inherited from the Triassic. Formed during the later stages of a rising sea-level, this horizon reflects a high carbonate production on the southern platform area. In the basin area, the second reef horizon presents relatively larger bodies (" patch reefs"). It consists of two major reef levels, separated by an interval of marls interspersed with thin-bedded limestones, developed most probably during Early? to Late Bajocian. For the duration of this time, within two 3rd order sequences, progradational shelfal units extended the platform facies northward to the basin center, covering a large area. Within a long-term transgressive/regressive cycle, throughout the Middle Aalenian-Bajocian, these reef horizons changed their structural growth to aggrading stacking patterns. The third reef horizon belongs to the lower part of the upper member of the Tazigzaout Formation, and shows the same sedimentary evolution as the second reef horizon underneath. It fits into a 2nd order geodynamic regressive cycle (upper part of Upper Bajocian-Bathonian pp.). It appears, that the development of the second and third reef horizon's forced the platform to prograde towards the N, NW and E during a late highstand, when accommodation was decreasing. However, depending on the

  14. Rindler-like Horizon in Spherically Symmetric Spacetime

    NASA Astrophysics Data System (ADS)

    Yang, Jinbo; He, Tangmei; Zhang, Jingyi

    2016-02-01

    In this paper, the Rindler-like horizon in a spherically symmetric spacetime is proposed. It is showed that just like the Rindler horizon in Minkowski spacetimes, there is also a Rindler-like horizon to a family of special observers in general spherically symmetric spacetimes. The entropy of this type of horizon is calculated with the thin film brick-wall model. The significance of entropy is discussed. Our results imply some connection between Bekeinstein-Hawking entropy and entanglement entropy.

  15. Rindler-like Horizon in Spherically Symmetric Spacetime

    NASA Astrophysics Data System (ADS)

    Yang, Jinbo; He, Tangmei; Zhang, Jingyi

    2016-07-01

    In this paper, the Rindler-like horizon in a spherically symmetric spacetime is proposed. It is showed that just like the Rindler horizon in Minkowski spacetimes, there is also a Rindler-like horizon to a family of special observers in general spherically symmetric spacetimes. The entropy of this type of horizon is calculated with the thin film brick-wall model. The significance of entropy is discussed. Our results imply some connection between Bekeinstein-Hawking entropy and entanglement entropy.

  16. Through the looking glass: why the `cosmic horizon' is not a horizon

    NASA Astrophysics Data System (ADS)

    van Oirschot, Pim; Kwan, Juliana; Lewis, Geraint F.

    2010-06-01

    The present standard model of cosmology, Λ cold dark matter (ΛCDM), contains some intriguing coincidences. Not only are the dominant contributions to the energy density approximately of the same order at the present epoch, but we also note that contrary to the emergence of cosmic acceleration as a recent phenomenon, the time-averaged value of the deceleration parameter over the age of the Universe is nearly zero. Curious features like these in ΛCDM give rise to a number of alternate cosmologies being proposed to remove them, including models with an equation of state w = -1/3. In this paper, we examine the validity of some of these alternate models and we also address some persistent misconceptions about the Hubble sphere and the event horizon that lead to erroneous conclusions about cosmology. Research undertaken as part of the Commonwealth Cosmology Initiative (CCI: http://www.thecci.org), an international collaboration supported by the Australian Research Council. E-mail: pimvanoirschot@gmail.com

  17. Analyticity of event horizons of five-dimensional multi-black holes with nontrivial asymptotic structure

    SciTech Connect

    Kimura, Masashi

    2008-08-15

    We show that there exist five-dimensional multi-black hole solutions which have analytic event horizons when the space-time has nontrivial asymptotic structure, unlike the case of five-dimensional multi-black hole solutions in asymptotically flat space-time.

  18. Rogue events in the group velocity horizon

    PubMed Central

    Demircan, Ayhan; Amiranashvili, Shalva; Brée, Carsten; Mahnke, Christoph; Mitschke, Fedor; Steinmeyer, Günter

    2012-01-01

    The concept of rogue waves arises from a mysterious and potentially calamitous phenomenon of oceanic surfaces. There is mounting evidence that they are actually commonplace in a variety of different physical settings. A set of defining criteria has been advanced; this set is of great generality and therefore applicable to a wide class of systems. The question arises naturally whether there are generic mechanisms responsible for extreme events in different systems. Here we argue that under suitable circumstances nonlinear interaction between weak and strong waves results in intermittent giant waves with all the signatures of rogue waves. To obtain these circumstances only a few basic conditions must be met. Then reflection of waves at the so-called group-velocity horizon occurs. The connection between rogue waves and event horizons, seemingly unrelated physical phenomena, is identified as a feature common in many different physical systems. PMID:23152941

  19. Horizon ratio bound for inflationary fluctuations.

    PubMed

    Dodelson, Scott; Hui, Lam

    2003-09-26

    We demonstrate that the gravity wave background amplitude implies a robust upper bound on the wavelength-to-horizon ratio at the end of inflation: lambda/H(-1) less than or approximately equal e(60), as long as the cosmic energy density does not drop faster than radiation subsequent to inflation. This limit implies that N, the number of e-folds between horizon exit and the end of inflation for wave modes of interest, is less, similar 60 plus a model-dependent factor-for vast classes of slow-roll models, N less than or approximately equal 67. As an example, this bound solidifies the tension between observations of the cosmic microwave background anisotropies and chaotic inflation with a phi(4) potential by closing the escape hatch of large N (<62). PMID:14525296

  20. Horizon Missions Technology Study. [for space exploration

    NASA Technical Reports Server (NTRS)

    Anderson, John L.

    1992-01-01

    The purpose of the HMT Study was to develop and demonstrate a systematic methodology for identifying and evaluating innovative technology concepts offering revolutionary, breadkthrough-type capabilities for advanced space missions and for assessing their potential mission impact. The methodology is based on identifying the new functional, operational and technology capabilities needed by hypothetical 'Horizon' space missions that have performance requirements that cannot be met, even by extrapolating known space technologies. Nineteen Horizon Missions were selected to represent a collective vision of advanced space missions of the mid-21st century. The missions typically would occur beyond the lifetime of current or planned space assets. The HM methodology and supporting data base may be used for advanced technology planning, advanced mission planning and multidisciplinary studies and analyses.

  1. Horizon crossing and inflation with large {eta}

    SciTech Connect

    Kinney, William H.

    2005-07-15

    I examine the standard formalism of calculating curvature perturbations in inflation at horizon crossing, and derive a general relation which must be satisfied for the horizon-crossing formalism to be valid. This relation is satisfied for the usual cases of power-law and slow-roll inflation. I then consider a model for which the relation is strongly violated, and the curvature perturbation evolves rapidly on superhorizon scales. This model has Hubble slow-roll parameter {eta}=3, but predicts a scale-invariant spectrum of density perturbations. I consider the case of hybrid inflation with large {eta}, and show that such solutions do not solve the '{eta} problem' in supergravity. These solutions correspond to field evolution which has not yet relaxed to the inflationary attractor solution, and may make possible new, more natural models on the string landscape.

  2. Finding apparent horizons in numerical relativity

    NASA Astrophysics Data System (ADS)

    Thornburg, Jonathan

    1996-10-01

    We review various algorithms for finding apparent horizons in 3+1 numerical relativity. We then focus on one particular algorithm, in which we pose the apparent horizon equation H≡∇ini+Kijninj-K=0 as a nonlinear elliptic (boundary-value) PDE on angular-coordinate space for the horizon shape function r=h(θ,φ), finite difference this PDE, and use Newton's method or a variant to solve the finite difference equations. We describe a method for computing the Jacobian matrix of the finite differenced H(h) sH (sh) function by symbolically differentiating the finite difference equations, giving the Jacobian elements directly in terms of the finite difference molecule coefficients used in computing sH (sh). Assuming the finite differencing scheme commutes with linearization, we show how the Jacobian elements may be computed by first linearizing the continuum H(h) equations, then finite differencing the linearized continuum equations. (This is essentially just the ``Jacobian part'' of the Newton-Kantorovich method for solving nonlinear PDEs.) We tabulate the resulting Jacobian coefficients for a number of different sH (sh) and Jacobian computation schemes. We find this symbolic differentiation method of computing the Jacobian to be much more efficient than the usual numerical-perturbation method, and also much easier to implement than is commonly thought. When solving the discrete sH (sh)=0 equations, we find that Newton's method generally shows robust convergence. However, we find that it has a small (poor) radius of convergence if the initial guess for the horizon position contains significant high-spatial-frequency error components, i.e., angular Fourier components varying as (say) cosmθ with m>~8. (Such components occur naturally if spacetime contains significant amounts of high-frequency gravitational radiation.) We show that this poor convergence behavior is not an artifact of insufficient resolution in the finite difference grid; rather, it appears to be caused

  3. Transformation of polymetallic dust in the organic horizon of Al-Fe-humus podzol (field experiment)

    NASA Astrophysics Data System (ADS)

    Lyanguzova, I. V.; Goldvirt, D. K.; Fadeeva, I. K.

    2015-07-01

    Scanning electron microscopy with an X-ray spectral microanalysis showed that the ash matter from the organic horizons (after ignition) of control and experimental plots mainly (>85%) consists of different soil-forming minerals and iron oxides (particularly magnetite). From 10% to 15% of particles in the organic horizon of Al-Fe-humus podzol (Albic Rustic Podzol) of the experimental plot were represented by polymetallic ball-shaped dust particles that were preserved in the soil without significant transformation for 14 years after their artificial application. The total contents of Cu, Pb, As, and Ni in the organic horizon on the experimental plot were 22-100 times higher than those in the control; the contents of Zn and Fe were 2-5 times higher. The sequence of chemical elements according to their total contents in the samples of control and experimental plots was different. The portion of available forms of heavy metal (Ni, Cu, and Co) compounds extractable with 1.0 M HCl averaged 20-30% of their total contents in the soil. More than 80% of acid-soluble forms of heavy metals were concentrated in the organic horizon of contaminated podzol soil, which represents the biogeochemical barrier to the migration of pollutants down the soil profile. Durable fixation of heavy metals in the organic horizon and their weak migration into the mineral soil layers significantly hamper the processes of self-purification of contaminated soils.

  4. Cosmo-geo-anthropo-logical history and political and deep future events in climate and life evolution conveyed by a physical/virtual installation at a scale of 1 mm per 100 years across Denmark during the COP15 climate summit meeting.

    NASA Astrophysics Data System (ADS)

    Holm Jacobsen, Bo

    2010-05-01

    During the COP15 climate summit meeting a physical and virtual installation of time was performed at a linear scale of 1 mm per 100 years. The "track of time" was carefully anchored geographically so that highlights in time history coincided with landmarks of historical and cultural significance to both tourists and the local Danish population; with Big Bang at the site of early royal settlements from the Viking age (13.7 billion years ~ 137 km from now), Earth origin at Kronborg in Elsinore (4.6 bil. Years ~ 46 km), and fish go on land at The Little Mermaid (390 mil. Years ~ 3900 m). The venue of the COP15 meeting coincided with the position of severe global warming, driven by the steady solar constant increase, to be expected 600 million years into the future. Nested in this grand track of time were the Quaternary ice-ages (2.6 mil. years ~ 26 m), human origin as species (100,000 years ~ 1 m), human history (< 10,000 years ~ 100 mm), personal life and the scope of political consequences of voting action (100 years ~ 1 mm). This installation of time involved several media. Highlights in time history and future were installed as a kml-file so that the convenient user interface of Google Earth could be utilized to provide both overview of time and understanding of details and proportions events antropo-geo-cosmo-history. Each Google Earth marker-balloon gave short explanations and linked to "on location" video-narratives. A classical printed text-folder was prepared as a tour guide for those who wanted to actually walk the Phanerozoic (~5 km). Credit-card-shaped graphs of temperature, CO2 and sealevel development and scenarios were prepared to scale for the period 4000 BP to 1000 years into the future. Along the time line from "Fish on land" to the present 3900 chalk marks were placed on the street surface, one for every metre = time span of Man as a species so far. A "NowGate" marking the present was implemented physically as a door frame, where citizens could meet

  5. Finding KBO flyby targets for New Horizons

    NASA Astrophysics Data System (ADS)

    Spencer, John; Trilling, David; Buie, Marc; Parker, Alex; Tholen, David; Stern, S. Alan

    2014-02-01

    We propose to continue the search for Kuiper Belt Objects (KBOs) that can be reached by the New Horizons spacecraft after its 2015 Pluto flyby. This first flyby of a small (~50 km) KBO would revolutionize our understanding of KBOs, providing information that can be extrapolated to hundreds of thousands of similar KBOs. Our 2011 search discovered three objects that could be targeted with only about twice the fuel that New Horizons has available during excellent seeing, but seeing was insufficient to achieve this depth over the entire search area in 2012 or 2013. Deepening the search in 2014, taking advantage of lower star density and the shrinking search area, has a good chance of finding a targetable object given sufficiently good seeing, especially with Hyper Suprime Cam. We expect about 2.5 targetable objects with R less 26.0 in the HSC field of view. We will also refine the orbits of previously discovered objects, including ones that can be observed from a distance by New Horizons on its passage through the Kuiper Belt.

  6. Accurate, reliable prototype earth horizon sensor head

    NASA Technical Reports Server (NTRS)

    Schwarz, F.; Cohen, H.

    1973-01-01

    The design and performance is described of an accurate and reliable prototype earth sensor head (ARPESH). The ARPESH employs a detection logic 'locator' concept and horizon sensor mechanization which should lead to high accuracy horizon sensing that is minimally degraded by spatial or temporal variations in sensing attitude from a satellite in orbit around the earth at altitudes in the 500 km environ 1,2. An accuracy of horizon location to within 0.7 km has been predicted, independent of meteorological conditions. This corresponds to an error of 0.015 deg-at 500 km altitude. Laboratory evaluation of the sensor indicates that this accuracy is achieved. First, the basic operating principles of ARPESH are described; next, detailed design and construction data is presented and then performance of the sensor under laboratory conditions in which the sensor is installed in a simulator that permits it to scan over a blackbody source against background representing the earth space interface for various equivalent plant temperatures.

  7. Horizon Science Experiment for Mars Global Surveyor

    NASA Astrophysics Data System (ADS)

    Martin, T. Z.

    1997-07-01

    The Mars Horizon Sensor Assembly on the MGS orbiter monitors the orientation of the spacecraft relative to the limb by sensing atmospheric emission in the 15 mu m CO2 band. These data are used to maintain nadir pointing for the remote sensing instrument suite. The set of 5.5deg tall triangular fields of view normally straddle the limb, and cover quadrants 90deg apart around the limb. As an engineering device, the MHSA benefits from Mars' atmosphere being spatially bland at 15 mu m. However, these data will carry information about the thermal state of the atmosphere, which is subject to diurnal, seasonal, latitudinal, and dust-storm related variations, as well as possible wave effects. The Mariner 7 IRS, Mariner 9 IRIS, and Viking IRTM all demonstrated such variability. The Horizon Science Experiment (HORSE) is intended to glean new insight into atmospheric variation from the MGS horizon sensors, with continuous data flow to the Earth in the engineering stream, and a rapid buildup of spatial coverage. MHSA data will also be used to monitor atmospheric thermal behavior during the aerobraking of MGS in late 1997.

  8. The Tookoonooka marine impact horizon, Australia: Sedimentary and petrologic evidence

    NASA Astrophysics Data System (ADS)

    Bron, Katherine A.; Gostin, Victor

    2012-02-01

    Ejecta from the large subsurface Tookoonooka impact structure have been found in the Lower Cretaceous strata of the extensive Eromanga Basin of central Australia. Observations from 31 wells spanning 400,000 km2 of the basin provide compelling evidence for the presence of a marine impact horizon of regional extent. Drill core was examined to determine the sedimentary context of the Tookoonooka impact event, the presence of ejecta, and the nature of the impact horizon. The base of the Wyandra Sandstone Member of the Cadna-owie Formation is an unconformity commonly overlain by very poorly sorted sediment with imbricated pebbles, exotic clasts, and occasional boulders. The basal Wyandra Sandstone Member is bimodal: a fine sand mode reflects an ambient sediment contribution and a coarse mode is interpreted to be impact-derived. Wells Thargomindah-1 and Eromanga-1, within four crater radii of Tookoonooka, contain distinctive clast-supported breccia-conglomerate beds at the base of the Wyandra Sandstone Member. Clasts in these beds include altered accretionary and melt impactoclasts, as well as lithic and mineral grains corresponding to the Tookoonooka target rock sequence, including basement. Petrographic evidence includes shock metamorphosed quartz and lithic grains with planar deformation features. These breccia-conglomerates are in stark contrast to the underlying, laterally persistent, unimodal Cadna-owie sediments and overlying shales deposited in an epeiric sea. The base of the Wyandra Sandstone Member is therefore interpreted to be the Tookoonooka impact horizon. The timing of the impact event is confirmed to be the Barremian-Aptian boundary, at 125 ± 1 Ma. The Wyandra Sandstone Member preserves both impact ejecta and postimpact marine sediments.

  9. Is the Gravitational-Wave Ringdown a Probe of the Event Horizon?

    NASA Astrophysics Data System (ADS)

    Cardoso, Vitor; Franzin, Edgardo; Pani, Paolo

    2016-04-01

    It is commonly believed that the ringdown signal from a binary coalescence provides a conclusive proof for the formation of an event horizon after the merger. This expectation is based on the assumption that the ringdown waveform at intermediate times is dominated by the quasinormal modes of the final object. We point out that this assumption should be taken with great care, and that very compact objects with a light ring will display a similar ringdown stage, even when their quasinormal-mode spectrum is completely different from that of a black hole. In other words, universal ringdown waveforms indicate the presence of light rings, rather than of horizons. Only precision observations of the late-time ringdown signal, where the differences in the quasinormal-mode spectrum eventually show up, can be used to rule out exotic alternatives to black holes and to test quantum effects at the horizon scale.

  10. Is the Gravitational-Wave Ringdown a Probe of the Event Horizon?

    PubMed

    Cardoso, Vitor; Franzin, Edgardo; Pani, Paolo

    2016-04-29

    It is commonly believed that the ringdown signal from a binary coalescence provides a conclusive proof for the formation of an event horizon after the merger. This expectation is based on the assumption that the ringdown waveform at intermediate times is dominated by the quasinormal modes of the final object. We point out that this assumption should be taken with great care, and that very compact objects with a light ring will display a similar ringdown stage, even when their quasinormal-mode spectrum is completely different from that of a black hole. In other words, universal ringdown waveforms indicate the presence of light rings, rather than of horizons. Only precision observations of the late-time ringdown signal, where the differences in the quasinormal-mode spectrum eventually show up, can be used to rule out exotic alternatives to black holes and to test quantum effects at the horizon scale. PMID:27176511

  11. Neural network-based finite horizon stochastic optimal control design for nonlinear networked control systems.

    PubMed

    Xu, Hao; Jagannathan, Sarangapani

    2015-03-01

    The stochastic optimal control of nonlinear networked control systems (NNCSs) using neuro-dynamic programming (NDP) over a finite time horizon is a challenging problem due to terminal constraints, system uncertainties, and unknown network imperfections, such as network-induced delays and packet losses. Since the traditional iteration or time-based infinite horizon NDP schemes are unsuitable for NNCS with terminal constraints, a novel time-based NDP scheme is developed to solve finite horizon optimal control of NNCS by mitigating the above-mentioned challenges. First, an online neural network (NN) identifier is introduced to approximate the control coefficient matrix that is subsequently utilized in conjunction with the critic and actor NNs to determine a time-based stochastic optimal control input over finite horizon in a forward-in-time and online manner. Eventually, Lyapunov theory is used to show that all closed-loop signals and NN weights are uniformly ultimately bounded with ultimate bounds being a function of initial conditions and final time. Moreover, the approximated control input converges close to optimal value within finite time. The simulation results are included to show the effectiveness of the proposed scheme. PMID:25720004

  12. Chandra Uncovers New Evidence For Event Horizons Surrounding Black Holes

    NASA Astrophysics Data System (ADS)

    2001-01-01

    horizon is the defining characteristic of a black hole, but obviously it is very difficult to detect since any infalling material at the event horizon is observable for only an instant as it plunges inward at the speed of light," said McClintock. "The comparison of black holes and their close cousins, the neutron stars, may be the most promising way to get a handle on the event horizon." If the collapsed star is a neutron star with a solid surface, energy must be released when infalling matter strikes that surface. In contrast, if the accreting object is a black hole, there is no surface for the matter to strike. Instead, both the energy and the matter will be lost from view forever once they cross the event horizon. A small amount of energy can escape just before the matter crosses the event horizon, but the scientists believe that it should be much less than the energy released by matter hitting a neutron star surface. "Watching matter flowing into a black hole is like sitting upstream of a waterfall and watching the water seemingly vanish over the edge," said Narayan, chairman of the Harvard Astronomy Department. "However, if the waterfall were replaced by a dam -- the analog of a neutron star surface -- then the water would pile up and one would see a mighty lake". Why are dormant black hole sources a hundred times fainter than the neutron star sources? The amount of material falling towards the collapsed star and the subsequent energy release are believed to be nearly the same, whether the compact object is a black hole or a neutron star. Therefore, the remarkable difference in brightness comes, according to the team, because of the event horizon, where the inward pull of gravity becomes infinitely strong. This is in contrast to the situation of neutron stars that have a more normal surface. By observing the motion of the companion star in an X-ray nova, the mass of the collapsed star can be estimated. In some cases, this mass is more than three times that of the Sun

  13. Miklós Konkoly Thege (1842-1916). 100 Years of Observational Astronomy and Astrophysics - A collection of papers on the history of Observational Astrophysics.

    NASA Astrophysics Data System (ADS)

    Sterken, C.; Hearnshaw, J. B.

    2001-10-01

    This book results from presentations and discussions by a group of astronomers and historians during a three-day workshop held at Tihany (Hungary), on 13-15 August 1999. This meeting - the second forum dedicated to the rise of observational astrophysics in the nineteenth and early twentieth century - coincided with the centenary of Hungary's national observatory. The basic principle of this series of meetings is to reflect on the work and personality of a single individual or of a group of persons, at the same time avoiding the really dominant figures that typify the age. The series focuses on key people who epitomize a way of thinking and working, that has in turn formed many of the ideas by which we do astrophysical research today. Hence the evocation of the scientific spirit of the era under consideration is attempted. Such a leading key person undoubtedly was Miklós Konkoly Thege. A superb instrumentalist and observer, Konkoly became the founding father of Hungarian astronomy through the establishment of his private observatory that later became the Royal Hungarian Ógyalla Observatory, the precursor of the modern Konkoly Observatory. The workshop was organized at the occasion of the centennial anniversary of Konkoly Observatory. The book outlines five major themes. The first part describes the birth of observational astrophysics in Hungary and focuses on historical aspects of 19th century Hungarian astronomy from three different viewpoints: the historical narrative based on historical facts, the perspective as seen by an expert in historical instrumentation, and a discussion of the socio-political consequences of nineteenth-century developments for our present times. The second part analyses the birth of observational astrophysics in countries with which Konkoly and his collaborators had close contacts: Japan, South Africa and France. The third part of the book discusses the establishment of the discipline of photometry worldwide. An important aspect of 19th

  14. Use of microcomputer in mapping depth of stratigraphic horizons in National Petroleum Reserve in Alaska

    USGS Publications Warehouse

    Payne, Thomas G.

    1982-01-01

    REGIONAL MAPPER is a menu-driven system in the BASIC language for computing and plotting (1) time, depth, and average velocity to geologic horizons, (2) interval time, thickness, and interval velocity of stratigraphic intervals, and (3) subcropping and onlapping intervals at unconformities. The system consists of three programs: FILER, TRAVERSER, and PLOTTER. A control point is a shot point with velocity analysis or a shot point at or near a well with velocity check-shot survey. Reflection time to and code number of seismic horizons are filed by digitizing tablet from record sections. TRAVERSER starts at a point of geologic control and, in traversing to another, parallels seismic events, records loss of horizons by onlap and truncation, and stores reflection time for geologic horizons at traversed shot points. TRAVERSER is basically a phantoming procedure. Permafrost thickness and velocity variations, buried canyons with low-velocity fill, and error in seismically derived velocity cause velocity anomalies that complicate depth mapping. Two depths to the top of the pebble is based shale are computed for each control point. One depth, designated Zs on seismically derived velocity. The other (Zw) is based on interval velocity interpolated linearly between wells and multiplied by interval time (isochron) to give interval thickness. Z w is computed for all geologic horizons by downward summation of interval thickness. Unknown true depth (Z) to the pebble shale may be expressed as Z = Zs + es and Z = Zw + ew where the e terms represent error. Equating the two expressions gives the depth difference D = Zs + Zw = ew + es A plot of D for the top of the pebble shale is readily contourable but smoothing is required to produce a reasonably simple surface. Seismically derived velocity used in computing Zs includes the effect of velocity anomalies but is subject to some large randomly distributed errors resulting in depth errors (es). Well-derived velocity used in computing Zw

  15. Magnetic signatures recorded in rocks and trees located inside the Tunguska blast 100 years ago, implications for Mirror Matter, Comet, and Kimberlitic Pipe explosion hypotheses

    NASA Astrophysics Data System (ADS)

    Kletetschka, G.

    2008-12-01

    Hundred years ago an unknown object impacted in Siberia, Tunguska region and created a seismic signature 100-1000 times stronger that the Hiroshima explosion. To this day, nothing has been found to suggest a foreign material (e.g. meteoritic) dispersion during this event. Various hypotheses were put forward, for example: Comet impact, Kimberlite Pipe explosion, and Mirror Matter interaction with the regular matter. We collected samples of black chert, conglomerate and wood from 5 different locations within 2 km from the epicenter. We used these samples for magnetic analysis and searched for any evidence of magnetic contamination that may date the Tunguska blast. All samples, wood, chert, and conglomerate showed sufficient content of magnetic material that should be capable of recording strong magnetic pulse. Our analysis shows no evidence of magnetic enhancement recorded in any of the three types (Chert, wood and conglomerate) of Tunguska samples. We will discuss this result in terms of three possible hypotheses of the created the Tunguska event.

  16. Testing numerically the null Cauchy horizon singularity inside Kerr black holes

    NASA Astrophysics Data System (ADS)

    Burko, Lior; Khanna, Gaurav; Zenginoĝlu, Anil

    2015-04-01

    The Cauchy horizon inside a Kerr black hole develops an instability that transforms it into a curvature singularity. Perturbative analyses are consistent with the picture arising from fully nonlinear simulations of spherical charged black holes: this singularity is deformational weak and null for early retarded times. Despite much interest in this long-standing problem, no numerical simulations of the interior of a perturbed Kerr black hole have been done to date. Here, we report on preliminary results obtained from a linear simulation of the evolution of the fields under the collapse of a test wave packet. We use recent developments to a Teukolsky equation solver, which use (event) horizon-penetrating, hyperboloidal coordinates, which compactify null infinity and penetrate through both horizons. This numerical technology allows us to penetrate through the event horizon, and probe the fields on the approach to the Cauchy horizon singularity. We study the behavior of the Weyl scalars ψ0 and ψ4 and of the curvature scalar RαβγδRαβγδ , and confront our results with those of perturbation analysis. Our results may be useful when planning fully nonlinear numerical studies of rotating black hole interiors.

  17. The quantum nonthermal radiation and horizon surface gravity of an arbitrarily accelerating black hole with electric charge and magnetic charge

    NASA Astrophysics Data System (ADS)

    Xie, Zhi-Kun; Pan, Wei-Zhen; Yang, Xue-Jun

    2013-03-01

    Using a new tortoise coordinate transformation, we discuss the quantum nonthermal radiation characteristics near an event horizon by studying the Hamilton-Jacobi equation of a scalar particle in curved space-time, and obtain the event horizon surface gravity and the Hawking temperature on that event horizon. The results show that there is a crossing of particle energy near the event horizon. We derive the maximum overlap of the positive and negative energy levels. It is also found that the Hawking temperature of a black hole depends not only on the time, but also on the angle. There is a problem of dimension in the usual tortoise coordinate, so the present results obtained by using a correct-dimension new tortoise coordinate transformation may be more reasonable.

  18. A multi-data set comparison of the vertical structure of temperature variability and change over the Arctic during the past 100 years

    NASA Astrophysics Data System (ADS)

    Brönnimann, Stefan; Grant, Andrea N.; Compo, Gilbert P.; Ewen, Tracy; Griesser, Thomas; Fischer, Andreas M.; Schraner, Martin; Stickler, Alexander

    2012-10-01

    We compare the daily, interannual, and decadal variability and trends in the thermal structure of the Arctic troposphere using eight observation-based, vertically resolved data sets, four of which have data prior to 1948. Comparisons on the daily scale between historical reanalysis data and historical upper-air observations were performed for Svalbard for the cold winters 1911/1912 and 1988/1989, the warm winters 1944/1945 and 2005/2006, and the International Geophysical Year 1957/1958. Excellent agreement is found at mid-tropospheric levels. Near the ground and at the tropopause level, however, systematic differences are identified. On the interannual time scale, the correlations between all data sets are high, but there are systematic biases in terms of absolute values as well as discrepancies in the magnitude of the variability. The causes of these differences are discussed. While none of the data sets individually may be suitable for trend analysis, consistent features can be identified from analyzing all data sets together. To illustrate this, we examine trends and 20-year averages for those regions and seasons that exhibit large sea-ice changes and have enough data for comparison. In the summertime Pacific Arctic and the autumn eastern Canadian Arctic, the lower tropospheric temperature anomalies for the recent two decades are higher than in any previous 20-year period. In contrast, mid-tropospheric temperatures of the European Arctic in the wintertime of the 1920s and 1930s may have reached values as high as those of the late 20th and early 21st centuries.

  19. Radio Occultation Measurements of Pluto's Atmosphere with New Horizons

    NASA Astrophysics Data System (ADS)

    Hinson, D. P.; Linscott, I.; Tyler, G. L.; Bird, M. K.; Paetzold, M.; Strobel, D. F.; Summers, M. E.; Woods, W. W.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Young, L. A.; Ennico Smith, K.; Gladstone, R.; Greathouse, T.; Kammer, J.; Parker, A. H.; Parker, J. W.; Retherford, K. D.; Schindhelm, E.; Singer, K. N.; Steffl, A.; Tsang, C.; Versteeg, M.

    2015-12-01

    The reconnaissance of the Pluto System by New Horizons included radio occultations at both Pluto and Charon. This talk will present the latest results from the Pluto occultation. The REX instrument onboard New Horizons received and recorded uplink signals from two 70-m antennas and two 34-m antennas of the NASA Deep Space Network - each transmitting 20 kW at 4.2-cm wavelength - during a diametric occultation by Pluto. At the time this was written only a short segment of data at occultation entry (193°E, 17°S) was available for analysis. The REX measurements extend unequivocally to the surface, providing the first direct measure of the surface pressure and the temperature structure in Pluto's lower atmosphere. Preliminary analysis yields a surface pressure of about 10 microbars, smaller than expected. Data from occultation exit (16°E, 15°N) are scheduled to arrive on the ground in late August 2015. Those observations will yield an improved estimate of the surface pressure, a second temperature profile, and a measure of the diameter of Pluto with a precision of a few hundred meters.

  20. Lagrangian Predictive Skill Assessment for the Deepwater Horizon Spill

    NASA Astrophysics Data System (ADS)

    Lipphardt, B. L.; Huntley, H. S.; Sulman, M.; Kirwan, A. D.

    2011-12-01

    The explosion and sinking of the Deepwater Horizon drilling platform produced enormous human, ecological, and economic impacts. At the same time this disaster provided an unprecedented amount of Lagrangian information on ocean processes, including a large number of surface and near-surface drifters deployed in the northeastern Gulf of Mexico as well as remotely sensed images of the surface oil slick. In addition several global and regional ocean model predictions were used to forecast the spill movements. These models generally exhibited large variations in the mesoscale flow near the Deepwater Horizon site, even though they all assimilated similar sets of ocean observations. This provides a unique opportunity to thoroughly assess model Lagrangian predictive skill. Here, the predictive skill of one model, a regional implementation of the Hybrid Coordinate Ocean Model (HYCOM), is evaluated using data from more than 80 drifter trajectories in the northern Gulf of Mexico. These trajectories are compared with maps of Lagrangian coherent structures, computed from near-surface model velocities, to determine whether the observations are consistent with the larger scale transport structure predicted by the model. We also discuss new metrics to assess model Lagrangian predictive skill of the plume movement.

  1. First Results from the Mars Global Surveyor Horizon Science Experiment

    NASA Astrophysics Data System (ADS)

    Martin, Terry

    1998-09-01

    The Horizon Science Experiment (HORSE) uses the Mars Horizon Sensor Assembly on the MGS orbiter to measure 15 micrometer band thermal emission from the Martian atmosphere. During the first phase of aerobraking for MGS, from September 1997 through March 1998, one of the four MGS quadrants was pointed well onto the planet consistently during the near-periapsis braking passes, allowing the device to obtain data on the latitudinal variation of middle atmospheric temperature (0.2 - 2 mbar). Of particular interest were the effects of a prominent dust storm at Ls 224, and the strong gradient of temperature near the north polar cap. The dust storm produced 10-12K warming in the middle atmosphere across the latitude range from -50 to +60 degrees over a time period of 97 hrs. The increase was most pronounced at the longitudes near 330 where the storm originated in the southern hemisphere. During Ls 260-278, the latitude of steepest latitudinal temperature gradient (the location of the northern polar vortex) varied with longitude in a primarily wave 2 mode, with an amplitude of about 8 degrees and one maximum at 120 longitude. A small wave 1 term is also present.

  2. Book Review: 100 years of observational astronomy and astrophysics : homage to Miklos Konkoly Thege / C. Sterken, 2001 / Vrije Universiteit Brussel, 2001

    NASA Astrophysics Data System (ADS)

    Sterken, C.; Hearnshaw, J. B.

    Miklós Konkoly Thege (1842-1916) was a wealthy Hungarian nobleman who established a private observatory at Ógyalla, nowadays a state institution known as the Konkoly Observatory. This interesting book is the proceedings of a workshop held in 1999 to celebrate the 100th anniversary of the founding of the Astronomical Research Institute of the Hungarian Academy of Sciences, based on the Konkoly Observatory. There are five parts to the book. The first is about the history of the Konkoly Observatory and its activities. Konkoly Thege was very active in instrumental matters - his book Praktische Anleitung ... (1883) was influential during the period when astrophysics was undergoing its first period of rapid development, and a copy of it exists in the SAAO collection. Konkoly was a pioneer in astronomical photometry and spectroscopy and made use of the Zöllner visual photometer as well as the schraffierkassette method for photographic photometry. The second part of the book is concerned with early astrophysics in various countries. The article on Japanese astronomy around 1899 (by M Takeuti) deals with a period not covered by articles in English. At this time, Japan was still recovering from the two centuries of isolation imposed by the Edo Shogunate, and research astronomy was just beginning. CD Laney's Astronomy in the Dismal Swamp, a quirky collection of stories about the Royal Observatory, Cape, follows. Other chapters deal with the Marseille Observatory and the French astronomer Jules Janssen (1824-1907). Two articles by J Hearnshaw and K Staubermann deal with the history of astronomical photometry in the third part. The fourth part is about early female astronomers and the difficulties they faced, including paragraphs on Dorothea Klumpke (who married Isaac Roberts), Agnes Clerke, Maria Mitchell and the famous ladies of the Harvard Observatory who worked on spectral classification and the Cepheid period-luminosity relation. Most of the last part is a fascinating

  3. Observation of an optical event horizon in a silicon-on-insulator photonic wire waveguide.

    PubMed

    Ciret, Charles; Leo, François; Kuyken, Bart; Roelkens, Gunther; Gorza, Simon-Pierre

    2016-01-11

    We report on the first experimental observation of an optical analogue of an event horizon in integrated nanophotonic waveguides, through the reflection of a continuous wave on an intense pulse. The experiment is performed in a dispersion-engineered silicon-on-insulator waveguide. In this medium, solitons do not suffer from Raman induced self-frequency shift as in silica fibers, a feature that is interesting for potential applications of optical event horizons. As shown by simulations, this also allows the observation of multiple reflections at the same time on fundamental solitons ejected by soliton fission. PMID:26832243

  4. Transport of four pharmaceuticals in different horizons of three soil types

    NASA Astrophysics Data System (ADS)

    Kodesova, Radka; Svatkova, Paula; Klement, Ales; Jaksik, Ondrej; Golovko, Oksana; Fer, Miroslav; Kocarek, Martin; Nikodem, Antonin; Grabic, Roman

    2015-04-01

    Soil structure, which varies in different soil types and the horizons of these soil types, has a significant impact on water flow and contaminant transport in soils. Transport of many contaminants is in addition strongly influenced by their sorption on soil particles. Transport of four pharmaceuticals (sulfamethoxazole, trimethoprim, atenolol and carbamazepine) was studied in soil columns (a diameter of 10.5 cm and a height of 13 cm) taken from all diagnostic horizons of three different soil types (Haplic Luvisol, Greyic Phaeozem and Haplic Cambisol). The irrigation by water contaminated by a mixture of all four compounds followed by ponding infiltration of distilled water was simulated and water outflow and solute concentrations from the bottom of the soil sample was monitored in time. The highest infiltration rates were observed for soil samples from the Bt horizons of the Greyic Phaeozem that exhibited prismatic structure, followed by rates observed in the Ap horizons of the Haplic Luvisol, Greyic Phaeozem and Haplic Cambisol (due to their granular soil structure and presence of root channels). The lowest infiltration rate was measured for the Bw horizon of the Haplic Cambisol, which had a poorly developed soil structure and a low fraction of macropores. Compound discharge was however also highly affected by their sorption on solids. The highest mobility was observed for sulfamethoxazole followed by carbamazepine atenolol and trimethoprim, which corresponds to measured sorption isotherms. Mobility of ionizable compounds in different soil samples was influenced by pH (i.e. degree and form of their ionization) and sites available for absorption. Mobility of sulfamethoxazole decreased with decreasing pH (i.e. the largest sorption measured in horizons of the Haplic Cambisol). While mobility of atenolol and trimethoprim decreased with increasing base cation saturation, and with increasing organic matter content for carbamazepine. As result of both affects (i.e. soil

  5. The horizon of the lightest black hole

    NASA Astrophysics Data System (ADS)

    Calmet, Xavier; Casadio, Roberto

    2015-09-01

    We study the properties of the poles of the resummed graviton propagator obtained by resumming bubble matter diagrams which correct the classical graviton propagator. These poles have been previously interpreted as black holes precursors. Here, we show using the horizon wave-function formalism that these poles indeed have properties which make them compatible with being black hole precursors. In particular, when modeled with a Breit-Wigner distribution, they have a well-defined gravitational radius. The probability that the resonance is inside its own gravitational radius, and thus that it is a black hole, is about one half. Our results confirm the interpretation of these poles as black hole precursors.

  6. Peripheral Vision Horizon Display (PVHD). Corrected Copy

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A Canadian invention, the peripheral vision horizon display (PVHD), shows promise in alleviating vertigo or disorientation in pilots flying under instrument conditions and easing the piloting task when flying in weather or other conditions requiring close attention to aircraft attitude instruments. A diversity of research and applied work was being done to investigate and validate the benefits of the PVHD during the years immediately preceding this conference. Organizers of the conference were able to assemble a group of outstanding presenters representing academic, industrial, and military. The theoretical foundation and applied use of the PVHD are discussed, and results from operational tests are presented.

  7. Prolate horizons and the Penrose inequality

    SciTech Connect

    Tippett, Benjamin K.

    2009-05-15

    The Penrose inequality has so far been proven in cases of spherical symmetry and in cases of zero extrinsic curvature. The next simplest case worth exploring would be nonspherical, nonrotating black holes with nonzero extrinsic curvature. Following Karkowski et al.'s construction of prolate black holes, we define initial data on an asymptotically flat spacelike 3-surface with nonzero extrinsic curvature that may be chosen freely. This gives us the freedom to define the location of the apparent horizon such that the Penrose inequality is violated. We show that the dominant energy condition is violated at the poles for all cases considered.

  8. Black hole thermodynamics from Euclidean horizon constraints.

    PubMed

    Carlip, S

    2007-07-13

    To explain black hole thermodynamics in quantum gravity, one must introduce constraints to ensure that a black hole is actually present. I show that for a large class of black holes, such "horizon constraints" allow the use of conformal field theory techniques to compute the density of states, reproducing the Bekenstein-Hawking entropy in a nearly model-independent manner. One standard string theory approach to black hole entropy arises as a special case, lending support to the claim that the mechanism may be "universal." I argue that the relevant degrees of freedom are Goldstone-boson-like excitations arising from the weak breaking of symmetry by the constraints. PMID:17678209

  9. European scientists' proposals for HORIZON 2000+

    NASA Astrophysics Data System (ADS)

    1994-10-01

    This programme, which has been given the name Horizon 2000+, will be presented to the press at 0900h on Monday 17 October 1994 at ESA Headquarters in Paris by Professor Lodewijk Woltjer, who chaired the committee of European scientific community representatives set up to consider the proposals submitted, and Professor Roger Bonnet, ESA's Science Programme Director. Journalists wishing to attend this press breakfast are requested to complete and return the attached form, if possible by fax: (33.1) 42.73.76.90.

  10. Preferential Flow Paths Allow Deposition of Mobile Organic Carbon Deep into Soil B Horizons

    NASA Astrophysics Data System (ADS)

    Marin-Spiotta, E.; Chadwick, O.; Kramer, M. G.

    2009-12-01

    Most of our understanding of soil carbon (C) dynamics derives from the top 10 to 20 cm, although globally the majority of the bulk soil C pool is found below those depths. Mineral associated C in deep soil is more stable than that held in surface horizons, and its long-term persistence may contribute to sequestration of anthropogenic C. Carbon can enter deep soil horizons in multiple ways: through biologically-mediated or abiotic physical mixing, illuviation, root inputs, or through a physical disturbance that would cause the burial of an originally shallow organic horizon. In this study, we investigated the role of dissolved organic matter (DOM) in the transport and stabilization of soil C in tropical rainforest volcanic soils, where high rainfall, a highly productive forest, and dominance of highly reactive, non-crystalline minerals contribute to large soil C stocks at depth with long mean residence times. DOM plays an important role in many biological and chemical processes in soils, including nutrient transfer within and across ecosystems. Carbon storage in these soils is linked to movement of both DOC and particulate organic C along infiltration pathways. Climate and soil mineralogical properties create the right conditions for C to be pumped from the organic horizons where microbial activity is highest, to deep mineral horizons, where the potential for stabilization is greatest. High rainfall preserves hydrated short-range order minerals that are subject to strong shrinkage during occasional drought periods. The resulting cracks in subsurface B horizons become pathways for DOM complexed with Fe and Al moving in soil solution during subsequent wet periods. Preferential flow of these organically rich solutes and/or colloids moves C to depth where C, Fe and Al are preferentially deposited on near-vertical crack surfaces and along near-horizonal flow surfaces at horizon boundaries. Long-term deposition forms discontinuous Fe- and OM-cemented lamella that serve to

  11. Projecting Program Cost Over an Adequate Time Horizon.

    ERIC Educational Resources Information Center

    Spencer, Milton

    Planning Programming Budgeting Systems involve the introduction of three major operational concepts. First, the development of an analytical capability to examine in depth both agency objectives and the various programs to meet these objectives. Second, the formation of a five-year planning and programming process combined with a sophisticated…

  12. Time horizon for AFV emission savings under Tier 2

    SciTech Connect

    Saricks, C. L.

    2000-03-20

    Implementation of the Federal Tier 2 vehicular emission standards according to the schedule presented in the December, 1999 Final Rule will result in substantial reductions of NMHC, CO, NO{sub x}, and fine particle emissions from motor vehicles. Currently, when compared to Tier 1 and even NLEV certification requirements, the emissions performance of automobiles and light-duty trucks powered by non-petroleum (especially, gaseous) fuels (i.e., vehicles collectively termed AFVs) enjoy measurable advantage over their gasoline- and diesel-fueled counterparts over the full Federal Test Procedure and, especially, in Bag 1 (cold start). For the lighter end of these vehicle classes, this advantage may disappear shortly after 2004 under the new standards, but should continue for a longer period (perhaps beyond 2008) for the heavier end as well as for heavy-duty vehicles relative to diesel-fueled counterparts. Because of the continuing commitment of the U.S. Department of Energy's Clean Cities coalitions to the acquisition and operation of AFVs of many types and size classes, it is important for them to know in which classes their acquisitions will remain clear relative to the petroleum-fueled counterparts they might otherwise procure. This paper provides an approximate timeline for and expected magnitude of such savings, assuming that full implementation of the Tier 2 standards covering both vehicular emissions and fuel sulfur limits proceeds on schedule. The pollutants of interest are primary ozone precursors and fine particulate matter from fuel combustion.

  13. Acceleration of a Static Observer Near the Event Horizon of a Static Isolated Black Hole.

    ERIC Educational Resources Information Center

    Doughty, Noel A.

    1981-01-01

    Compares the magnitude of the proper acceleration of a static observer in a static, isolated, spherically symmetric space-time region with the Newtonian result including the situation in the interior of a perfect-fluid star. This provides a simple physical interpretation of surface gravity and illustrates the global nature of the event horizon.…

  14. ALUMINUM PRECIPITATION AND DISSOLUTION RATES IN SPODOSOL BS HORIZONS IN THE NORTHEASTERN USA

    EPA Science Inventory

    The kinetics of Al precipitation/dissolution reactions in Spodosol Bs horizons from sites at Hubbard Brook, NH and Bear Brook, ME were examined. echanical vacuum extractor was employed to draw solutions through soil columns at solution/soil residence times between 0.3 and 100 h. ...

  15. 78 FR 54298 - Horizons ETFs Management (USA) LLC and Horizons ETF Trust; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-03

    .... Applicants currently intend that the initial series of the Trust will be the Horizons Active Global Dividend... through either the NSCC or DTC; or (ii) in the case of Funds holding non-U.S. investment (``Global Funds... holder of Shares of a Global Fund would be subject to unfavorable income tax treatment if the...

  16. Killing horizons around a uniformly accelerating and rotating particle

    SciTech Connect

    Farhoosh, H.; Zimmerman, R.L.

    1980-08-15

    The structure of the Killing horizon surrounding a uniformly accelerating and rotating particle which is emitting gravitational radiation is investigated. When expressed in terms of a coordinate system which is rigidly fixed to the particle undergoing uniform acceleration, the two inner horizons and ergoregion are similar to the horizons and ergoregion in the Kerr solution. These compact surfaces are distorted by the acceleration, being elongated in the forward direction and contracted in the backward direction. In addition to the two horizons that are similar to the Kerr solution, there is an additional noncompact horizon and an additional ergoregion which are caused by the acceleration. In general, the two ergoregions are disjoint, but as the acceleration parameter is sufficiently increased these ergoregions coalesce. A further increase of the acceleration will cause the two outer horizons to become degenerate and the ergoregion to vanish. An increase in the rotation parameter causes effects similar to those in the Kerr metric.

  17. Killing horizons around a uniformly accelerating and rotating particle

    NASA Astrophysics Data System (ADS)

    Farhoosh, Hamid; Zimmerman, Robert L.

    1980-08-01

    The structure of the Killing horizon surrounding a uniformly accelerating and rotating particle which is emitting gravitational radiation is investigated. When expressed in terms of a coordinate system which is rigidly fixed to the particle undergoing uniform acceleration, the two inner horizons and ergoregion are similar to the horizons and ergoregion in the Kerr solution. These compact surfaces are distorted by the acceleration, being elongated in the forward direction and contracted in the backward direction. In addition to the two horizons that are similar to the Kerr solution, there is an additional noncompact horizon and an additional ergoregion which are caused by the acceleration. In general, the two ergoregions are disjoint, but as the acceleration parameter is sufficiently increased these ergoregions coalesce. A further increase of the acceleration will cause the two outer horizons to become degenerate and the ergoregion to vanish. An increase in the rotation parameter causes effects similar to those in the Kerr metric.

  18. The Flexner Report ― 100 Years Later

    PubMed Central

    Duffy, Thomas P.

    2011-01-01

    The Flexner Report of 1910 transformed the nature and process of medical education in America with a resulting elimination of proprietary schools and the establishment of the biomedical model as the gold standard of medical training. This transformation occurred in the aftermath of the report, which embraced scientific knowledge and its advancement as the defining ethos of a modern physician. Such an orientation had its origins in the enchantment with German medical education that was spurred by the exposure of American educators and physicians at the turn of the century to the university medical schools of Europe. American medicine profited immeasurably from the scientific advances that this system allowed, but the hyper-rational system of German science created an imbalance in the art and science of medicine. A catching-up is under way to realign the professional commitment of the physician with a revision of medical education to achieve that purpose. PMID:21966046

  19. Human Fetal Behavior: 100 Years of Study.

    ERIC Educational Resources Information Center

    Kisilevsky, B. S.; Low, J. A.

    1998-01-01

    Reviews literature on human fetal behavior. Includes descriptions of coupling of body movements and fetal heart rate and behavior maturation from conception to term. Discusses use of stimulus-induced behavior to examine sensory and cognitive development, and spontaneous and stimulus-induced behavior to assess fetal well-being. Notes research focus…

  20. A 100-year perspective on gastrointestinal motility.

    PubMed

    Szurszewski, J H

    1998-03-01

    This contribution to the centennial commemorative issue of the American Journal of Physiology: Gastrointestinal and Liver Physiology identifies some of the important studies of spontaneous electrical and motor activity in the gastrointestinal tract published in the Journal between 1898 and 1996. Emphasis is given to the contributions made by Walter B. Cannon, Walter C. Alvarez, Emil Bozler, C. Ladd Prosser, and James Christensen. PMID:9565541

  1. Beam Line: 100 years of elementary particles

    NASA Astrophysics Data System (ADS)

    Pais, A.; Weinberg, S.; Quigg, C.; Riordan, M.; Panofsky, W. K. H.

    1997-04-01

    This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

  2. 100 Years Werner Heisenberg: Works and Impact

    NASA Astrophysics Data System (ADS)

    Papenfuß, Dietrich; Lüst, Dieter; Schleich, Wolfgang P.

    2003-09-01

    Over 40 renowned scientists from all around the world discuss the work and influence of Werner Heisenberg. The papers result from the symposium held by the Alexander von Humboldt-Stiftung on the occasion of the 100th anniversary of Heisenberg's birth, one of the most important physicists of the 20th century and cofounder of modern-day quantum mechanics. Taking atomic and laser physics as their starting point, the scientists illustrate the impact of Heisenberg's theories on astroparticle physics, high-energy physics and string theory right up to processing quantum information.

  3. Dairy innovations over the past 100 Years.

    PubMed

    Tunick, Michael H

    2009-09-23

    The dairy industry in the United States has undergone many changes over the past century. Adulteration and contamination of milk were rampant before the passage and enforcement of the Pure Food and Drug Act of 1906, and the introduction and eventual acceptance of certified and pasteurized milk have provided consumers with a consistently safe product. Homogenization and advances in the packaging and transport of milk gradually took hold, improving the milk supply. Other developments included the concentration of milk and whey, lactose-reduced milk, and the popularization of yogurt. Consumers have benefited from advances in butter packaging, low-fat ice cream, cheese manufacture, and yogurt technology, which has helped create the large demand for dairy products in the United States. Current trends and issues, including the increasing popularity of organic and artisanal products and the use of rBST, will shape the future of the dairy industry. PMID:19719132

  4. The Flexner Report--100 years later.

    PubMed

    Duffy, Thomas P

    2011-09-01

    The Flexner Report of 1910 transformed the nature and process of medical education in America with a resulting elimination of proprietary schools and the establishment of the biomedical model as the gold standard of medical training. This transformation occurred in the aftermath of the report, which embraced scientific knowledge and its advancement as the defining ethos of a modern physician. Such an orientation had its origins in the enchantment with German medical education that was spurred by the exposure of American educators and physicians at the turn of the century to the university medical schools of Europe. American medicine profited immeasurably from the scientific advances that this system allowed, but the hyper-rational system of German science created an imbalance in the art and science of medicine. A catching-up is under way to realign the professional commitment of the physician with a revision of medical education to achieve that purpose. PMID:21966046

  5. Scoring functions--the first 100 years.

    PubMed

    Tame, Jeremy R H

    2005-06-01

    The use of simple linear mathematical models to estimate chemical properties is not a new idea. Albert Einstein used very simple 'gravity-like' forces to explain the capillarity of different liquids in 1900-1901. Today such models are used in more complicated situations, and a great many have been developed to analyse interactions between proteins and their ligands. This is not surprising, since proteins are too complicated to model accurately without lengthy numerical analysis, and simple models often do at least as good a job in predicting binding constants as much more computationally expensive methods. One hundred years after Einstein's 'miraculous year' in which he transformed physics, it is instructive to recall some of his even earlier work. As approximations, 'scoring functions' are excellent, but it is dangerous to read too much into them. A few cautionary tales are presented for the beginner to the field of ligand affinity prediction by linear models. PMID:16231202

  6. [The Einthoven's electrocardiograph after 100 years].

    PubMed

    de Micheli-Serra, A; Iturralde, P

    2001-01-01

    The initial studies about the "irritability" of animal tissues by iatrophysic and iatromechanic scientists are reviewed. These studies led to discover the so called animal electricity envisaged by Luigi Galvani in the XVIII century and demonstrated by Carlo Matteucci and his followers in the XIX. Beginning with the Galvani's "reoscopic" frog, which allowed to assess the electrical current in a qualitative sense, it was possible to arrive, at the beginnings of the XX century, to the string electrocardiograph presented by Willem Einthoven in 1901. This opened the way that led to fabrication of ever more sophisticated instruments until the present systems of endocardial mapping by magnetic technology or by multipolar catheters, which permit to quickly identify the site of origin or the spreading ways of a tachycardia for their ablation with radio-frequency. Intracardiac echocardiography is also employed to define the anatomy of right atrium, during intracardiac cartography, in order to establish the most adequate sites for ablation. On the other hand, a logic i.e. rational, method for the interpretation of results from the electrical exploration of the heart has been developed. This one was introduced by Frank N. Wilson in Ann Arbor and has been fittingly applied by Demetrio Sodi Pallares in Mexico. Important diagnostic advances and notable therapeutic inferences have been derived from these latter developments. PMID:11692816

  7. Spinoff 2003: 100 Years of Powered Flight

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Today, NASA continues to reach milestones in space exploration with the Hubble Telescope, Earth-observing systems, the Space Shuttle, the Stardust spacecraft, the Chandra X-Ray Observatory, the International Space Station, the Mars rovers, and experimental research aircraft these are only a few of the many initiatives that have grown out of NASA engineering know-how to drive the Agency s missions. The technical expertise gained from these programs has transferred into partnerships with academia, industry, and other Federal agencies, ensuring America stays capable and competitive. With Spinoff 2003, we once again highlight the many partnerships with U.S. companies that are fulfilling the 1958 Space Act stipulation that NASA s vast body of scientific and technical knowledge also benefit mankind. This year's issue showcases innovations such as the cochlear implant in health and medicine, a cockpit weather system in transportation, and a smoke mask benefiting public safety; many other products are featured in these disciplines, as well as in the additional fields of consumer/home/recreation, environment and resources management, computer technology, and industrial productivity/ manufactacturing technology. Also in this issue, we devote an entire section to NASA s history in the field of flight and showcase NASA s newest enterprise dedicated to education. The Education Enterprise will provide unique teaching and learning experiences for students and teachers at all levels in science, technology, engineering, and mathematics. The Agency also is committed, as never before, to engaging parents and families through NASA s educational resources, content, and opportunities. NASA s catalyst to intensify its focus on teaching and learning springs from our mission statement: to inspire the next generation of explorers as only NASA can.

  8. Analysis of 100 Years of Curriculum Designs

    ERIC Educational Resources Information Center

    Kelting-Gibson, Lynn

    2013-01-01

    Fifteen historical and contemporary curriculum designs were analyzed for elements of assessment that support student learning and inform instructional decisions. Educational researchers are purposely paying attention to the role assessment plays in a well-designed planning and teaching process. Assessment is a vital component to educational…

  9. Gribov's horizon and the ghost dressing function

    SciTech Connect

    Boucaud, Ph.; Leroy, J. P.; Le Yaouanc, A.; Micheli, J.; Pene, O.; Rodriguez-Quintero, J.

    2009-11-01

    We study a relation recently derived by K. Kondo at zero momentum between the Zwanziger's horizon function, the ghost dressing function and Kugo's functions u and w. We agree with this result as far as bare quantities are considered. However, assuming the validity of the horizon gap equation, we argue that the solution w(0)=0 is not acceptable since it would lead to a vanishing renormalized ghost dressing function. On the contrary, when the cutoff goes to infinity, u(0){yields}{infinity}, w(0){yields}-{infinity} such that u(0)+w(0){yields}-1. Furthermore w and u are not multiplicatively renormalizable. Relaxing the gap equation allows w(0)=0 with u(0){yields}-1. In both cases the bare ghost dressing function, F(0,{lambda}), goes logarithmically to infinity at infinite cutoff. We show that, although the lattice results provide bare results not so different from the F(0,{lambda})=3 solution, this is an accident due to the fact that the lattice cutoffs lie in the range 1-3 GeV{sup -1}. We show that the renormalized ghost dressing function should be finite and nonzero at zero momentum and can be reliably estimated on the lattice up to powers of the lattice spacing; from published data on a 80{sup 4} lattice at {beta}=5.7 we obtain F{sub R}(0,{mu}=1.5 GeV){approx_equal}2.2.

  10. Energy and information near black hole horizons

    SciTech Connect

    Freivogel, Ben

    2014-07-01

    The central challenge in trying to resolve the firewall paradox is to identify excitations in the near-horizon zone of a black hole that can carry information without injuring a freely falling observer. By analyzing the problem from the point of view of a freely falling observer, I arrive at a simple proposal for the degrees of freedom that carry information out of the black hole. An infalling observer experiences the information-carrying modes as ingoing, negative energy excitations of the quantum fields. In these states, freely falling observers who fall in from infinity do not encounter a firewall, but freely falling observers who begin their free fall from a location close to the horizon are ''frozen'' by a flux of negative energy. When the black hole is ''mined,'' the number of information-carrying modes increases, increasing the negative energy flux in the infalling frame without violating the equivalence principle. Finally, I point out a loophole in recent arguments that an infalling observer must detect a violation of unitarity, effective field theory, or free infall.

  11. Cool horizons lead to information loss

    NASA Astrophysics Data System (ADS)

    Chowdhury, Borun D.

    2013-10-01

    There are two evidences for information loss during black hole evaporation: (i) a pure state evolves to a mixed state and (ii) the map from the initial state to final state is non-invertible. Any proposed resolution of the information paradox must address both these issues. The firewall argument focuses only on the first and this leads to order one deviations from the Unruh vacuum for maximally entangled black holes. The nature of the argument does not extend to black holes in pure states. It was shown by Avery, Puhm and the author that requiring the initial state to final state map to be invertible mandates structure at the horizon even for pure states. The proof works if black holes can be formed in generic states and in this paper we show that this is indeed the case. We also demonstrate how models proposed by Susskind, Papadodimas et al. and Maldacena et al. end up making the initial to final state map non-invertible and thus make the horizon "cool" at the cost of unitarity.

  12. Radiation from quantum weakly dynamical horizons in loop quantum gravity.

    PubMed

    Pranzetti, Daniele

    2012-07-01

    We provide a statistical mechanical analysis of quantum horizons near equilibrium in the grand canonical ensemble. By matching the description of the nonequilibrium phase in terms of weakly dynamical horizons with a local statistical framework, we implement loop quantum gravity dynamics near the boundary. The resulting radiation process provides a quantum gravity description of the horizon evaporation. For large black holes, the spectrum we derive presents a discrete structure which could be potentially observable. PMID:23031096

  13. Dynamical horizons: energy, angular momentum, fluxes, and balance laws.

    PubMed

    Ashtekar, Abhay; Krishnan, Badri

    2002-12-23

    Dynamical horizons are considered in full, nonlinear general relativity. Expressions of fluxes of energy and angular momentum carried by gravitational waves across these horizons are obtained. Fluxes are local, the energy flux is positive, and change in the horizon area is related to these fluxes. The flux formulas also give rise to balance laws analogous to the ones obtained by Bondi and Sachs at null infinity and provide generalizations of the first and second laws of black-hole mechanics. PMID:12484807

  14. Restricted psychological horizon in active methamphetamine users: future, past, probability, and social discounting

    PubMed Central

    Yi, Richard; Carter, Anne E.; Landes, Reid D.

    2014-01-01

    Methamphetamine users (MAU) exhibit an exaggerated bias for immediate rewards that reflects a restricted time horizon, where outcomes in the future are excessively discounted. An accumulating literature indicates that time in the future shares features with other dimensions of psychological distances including time in the past probability, and social distance, suggesting that bias for immediacy may be reducible to a more general restriction of psychological horizon. The purpose of the present study was to explore generalized restricted psychological horizon in active MAU by assessing future, past, probability, and social discounting. Compared with nonusing controls, MAU preferred psychologically proximal outcomes, resulting in higher rates for all types of discounting, which supports the conceptualization that MAU insufficiently integrate outcomes of psychological distance (i.e. in the future, the past, probabilistic, for others) into the valuation of current behavioral alternatives. The present results are suggestive of a more fundamental process of problematic decision-making associated with methamphetamine use, indicating the necessity of more comprehensive approaches to address the generalized limitations of restricted psychological horizon. PMID:22743602

  15. Gravitational anomaly and Hawking radiation near a weakly isolated horizon

    SciTech Connect

    Wu Xiaoning; Huang Chaoguang; Sun Jiarui

    2008-06-15

    Based on the idea of the work by Wilczek and his collaborators, we consider the gravitational anomaly near a weakly isolated horizon. We find that there exists a universal choice of tortoise coordinate for any weakly isolated horizon. Under this coordinate, the leading behavior of a quite arbitrary scalar field near a horizon is a 2-dimensional chiral scalar field. This means we can extend the idea of Wilczek and his collaborators to more general cases and show the relation between gravitational anomaly and Hawking radiation is a universal property of a black hole horizon.

  16. Gravitational anomaly and Hawking radiation near a weakly isolated horizon

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoning; Huang, Chao-Guang; Sun, Jia-Rui

    2008-06-01

    Based on the idea of the work by Wilczek and his collaborators, we consider the gravitational anomaly near a weakly isolated horizon. We find that there exists a universal choice of tortoise coordinate for any weakly isolated horizon. Under this coordinate, the leading behavior of a quite arbitrary scalar field near a horizon is a 2-dimensional chiral scalar field. This means we can extend the idea of Wilczek and his collaborators to more general cases and show the relation between gravitational anomaly and Hawking radiation is a universal property of a black hole horizon.

  17. Into the Kuiper Belt: New Horizons Post-Pluto

    NASA Astrophysics Data System (ADS)

    Harrison Parker, Alex; Spencer, John; Benecchi, Susan; Binzel, Richard; Borncamp, David; Buie, Marc; Fuentes, Cesar; Gwyn, Stephen; Kavelaars, JJ; Noll, Keith; Petit, Jean-Marc; Porter, Simon; Showalter, Mark; Stern, S. Alan; Sterner, Ray; Tholen, David; Verbiscer, Anne; Weaver, Hal; Zangari, Amanda

    2015-11-01

    New Horizons is now beyond Pluto and flying deeper into the Kuiper Belt. In the summer of 2014, a Hubble Space Telescope Large Program identified two candidate Cold Classical Kuiper Belt Objects (KBOs) that were within reach of New Horizons' remaining fuel budget. Here we present the selection of the Kuiper Belt flyby target for New Horizons' post-Pluto mission, our state of knowledge regarding this target and the potential 2019 flyby, the status of New Horizons' targeting maneuver, and prospects for near-future long-range observations of other KBOs.

  18. Criticality and surface tension in rotating horizon thermodynamics

    NASA Astrophysics Data System (ADS)

    Hansen, Devin; Kubizňák, David; Mann, Robert B.

    2016-08-01

    We study a modified horizon thermodynamics and the associated criticality for rotating black hole spacetimes. Namely, we show that under a virtual displacement of the black hole horizon accompanied by an independent variation of the rotation parameter, the radial Einstein equation takes a form of a ‘cohomogeneity two’ horizon first law, δ E=Tδ S+{{Ω }}δ J-σ δ A, where E and J are the horizon energy (an analogue of the Misner–Sharp mass) and the horizon angular momentum, Ω is the horizon angular velocity, A is the horizon area, and σ is the surface tension induced by the matter fields. For fixed angular momentum, the above equation simplifies and the more familiar (cohomogeneity one) horizon first law δ E=Tδ S-Pδ V is obtained, where P is the pressure of matter fields and V is the horizon volume. A universal equation of state is obtained in each case and the corresponding critical behavior is studied.

  19. Perturbations of the Kerr spacetime in horizon-penetrating coordinates

    NASA Astrophysics Data System (ADS)

    Campanelli, Manuela; Khanna, Gaurav; Laguna, Pablo; Pullin, Jorge; Ryan, Michael P.

    2001-04-01

    We derive the Teukolsky equation for perturbations of a Kerr spacetime when the spacetime metric is written in either ingoing or outgoing Kerr-Schild form. We also write explicit formulae for setting up the initial data for the Teukolsky equation in the time domain in terms of a 3-metric and an extrinsic curvature. The motivation of this work is to have in place a formalism to study the evolution in the `close limit' of two recently proposed solutions to the initial-value problem in general relativity that are based on Kerr-Schild slicings. A perturbative formalism in horizon-penetrating coordinates is also very desirable in connection with numerical relativity simulations using black hole `excision'.

  20. The atmosphere of Pluto as observed by New Horizons

    NASA Astrophysics Data System (ADS)

    Gladstone, G. Randall; Stern, S. Alan; Ennico, Kimberly; Olkin, Catherine B.; Weaver, Harold A.; Young, Leslie A.; Summers, Michael E.; Strobel, Darrell F.; Hinson, David P.; Kammer, Joshua A.; Parker, Alex H.; Steffl, Andrew J.; Linscott, Ivan R.; Parker, Joel Wm.; Cheng, Andrew F.; Slater, David C.; Versteeg, Maarten H.; Greathouse, Thomas K.; Retherford, Kurt D.; Throop, Henry; Cunningham, Nathaniel J.; Woods, William W.; Singer, Kelsi N.; Tsang, Constantine C. C.; Schindhelm, Eric; Lisse, Carey M.; Wong, Michael L.; Yung, Yuk L.; Zhu, Xun; Curdt, Werner; Lavvas, Panayotis; Young, Eliot F.; Tyler, G. Leonard; Bagenal, F.; Grundy, W. M.; McKinnon, W. B.; Moore, J. M.; Spencer, J. R.; Andert, T.; Andrews, J.; Banks, M.; Bauer, B.; Bauman, J.; Barnouin, O. S.; Bedini, P.; Beisser, K.; Beyer, R. A.; Bhaskaran, S.; Binzel, R. P.; Birath, E.; Bird, M.; Bogan, D. J.; Bowman, A.; Bray, V. J.; Brozovic, M.; Bryan, C.; Buckley, M. R.; Buie, M. W.; Buratti, B. J.; Bushman, S. S.; Calloway, A.; Carcich, B.; Conard, S.; Conrad, C. A.; Cook, J. C.; Cruikshank, D. P.; Custodio, O. S.; Ore, C. M. Dalle; Deboy, C.; Dischner, Z. J. B.; Dumont, P.; Earle, A. M.; Elliott, H. A.; Ercol, J.; Ernst, C. M.; Finley, T.; Flanigan, S. H.; Fountain, G.; Freeze, M. J.; Green, J. L.; Guo, Y.; Hahn, M.; Hamilton, D. P.; Hamilton, S. A.; Hanley, J.; Harch, A.; Hart, H. M.; Hersman, C. B.; Hill, A.; Hill, M. E.; Holdridge, M. E.; Horanyi, M.; Howard, A. D.; Howett, C. J. A.; Jackman, C.; Jacobson, R. A.; Jennings, D. E.; Kang, H. K.; Kaufmann, D. E.; Kollmann, P.; Krimigis, S. M.; Kusnierkiewicz, D.; Lauer, T. R.; Lee, J. E.; Lindstrom, K. L.; Lunsford, A. W.; Mallder, V. A.; Martin, N.; McComas, D. J.; McNutt, R. L.; Mehoke, D.; Mehoke, T.; Melin, E. D.; Mutchler, M.; Nelson, D.; Nimmo, F.; Nunez, J. I.; Ocampo, A.; Owen, W. M.; Paetzold, M.; Page, B.; Pelletier, F.; Peterson, J.; Pinkine, N.; Piquette, M.; Porter, S. B.; Protopapa, S.; Redfern, J.; Reitsema, H. J.; Reuter, D. C.; Roberts, J. H.; Robbins, S. J.; Rogers, G.; Rose, D.; Runyon, K.; Ryschkewitsch, M. G.; Schenk, P.; Sepan, B.; Showalter, M. R.; Soluri, M.; Stanbridge, D.; Stryk, T.; Szalay, J. R.; Tapley, M.; Taylor, A.; Taylor, H.; Umurhan, O. M.; Verbiscer, A. J.; Versteeg, M. H.; Vincent, M.; Webbert, R.; Weidner, S.; Weigle, G. E.; White, O. L.; Whittenburg, K.; Williams, B. G.; Williams, K.; Williams, S.; Zangari, A. M.; Zirnstein, E.

    2016-03-01

    Observations made during the New Horizons flyby provide a detailed snapshot of the current state of Pluto's atmosphere. Whereas the lower atmosphere (at altitudes of less than 200 kilometers) is consistent with ground-based stellar occultations, the upper atmosphere is much colder and more compact than indicated by pre-encounter models. Molecular nitrogen (N2) dominates the atmosphere (at altitudes of less than 1800 kilometers or so), whereas methane (CH4), acetylene (C2H2), ethylene (C2H4), and ethane (C2H6) are abundant minor species and likely feed the production of an extensive haze that encompasses Pluto. The cold upper atmosphere shuts off the anticipated enhanced-Jeans, hydrodynamic-like escape of Pluto's atmosphere to space. It is unclear whether the current state of Pluto's atmosphere is representative of its average state - over seasonal or geologic time scales.

  1. The atmosphere of Pluto as observed by New Horizons.

    PubMed

    Gladstone, G Randall; Stern, S Alan; Ennico, Kimberly; Olkin, Catherine B; Weaver, Harold A; Young, Leslie A; Summers, Michael E; Strobel, Darrell F; Hinson, David P; Kammer, Joshua A; Parker, Alex H; Steffl, Andrew J; Linscott, Ivan R; Parker, Joel Wm; Cheng, Andrew F; Slater, David C; Versteeg, Maarten H; Greathouse, Thomas K; Retherford, Kurt D; Throop, Henry; Cunningham, Nathaniel J; Woods, William W; Singer, Kelsi N; Tsang, Constantine C C; Schindhelm, Eric; Lisse, Carey M; Wong, Michael L; Yung, Yuk L; Zhu, Xun; Curdt, Werner; Lavvas, Panayotis; Young, Eliot F; Tyler, G Leonard

    2016-03-18

    Observations made during the New Horizons flyby provide a detailed snapshot of the current state of Pluto's atmosphere. Whereas the lower atmosphere (at altitudes of less than 200 kilometers) is consistent with ground-based stellar occultations, the upper atmosphere is much colder and more compact than indicated by pre-encounter models. Molecular nitrogen (N2) dominates the atmosphere (at altitudes of less than 1800 kilometers or so), whereas methane (CH4), acetylene (C2H2), ethylene (C2H4), and ethane (C2H6) are abundant minor species and likely feed the production of an extensive haze that encompasses Pluto. The cold upper atmosphere shuts off the anticipated enhanced-Jeans, hydrodynamic-like escape of Pluto's atmosphere to space. It is unclear whether the current state of Pluto's atmosphere is representative of its average state--over seasonal or geologic time scales. PMID:26989258

  2. Learn to Change: Teaching Toward a Shifting Health Care Horizon.

    PubMed

    Hart, Laura C

    2016-01-01

    Changes in health care-including a growing emphasis on quality, outcomes, and lower costs-are transforming the delivery of care and creating a knowledge gap that continuing education must bridge. As clinicians and health leaders spend less time in hospital settings, educational activities are likely to extend their reach, for instance through online education distributed on laptops, tablets, or smartphones. Ezekiel J. Emanuel, MD, PhD, explored this shift in his 2016 keynote to the World Congress for Continuing Professional Development: "Learn to Change: Teaching Toward a Shifting Health Care Horizon." This article describes some of the main trends in health care that Dr. Emanuel foresees, focusing on the implications of the changing role of hospitals for innovation in continuing education. PMID:27584062

  3. Attitude Determination by Using Horizon and Sun Sensors

    NASA Technical Reports Server (NTRS)

    Huang, Allen K. H.; French, Larry A.

    1993-01-01

    The Pointing and Alignment Workstation (PAWS) developed by Teledyne Brown Engineering (TBE) has successfully supported the first and second Atmospheric Laboratory for Applications and Science (ATLAS 1, 2) spacelab missions for NASA. The primary PAWS objective was to provide realtime pointing information to instruments whose line of-sight is dependent on Shuttle attitude and to study/quantify the causes and effects of Shuttle and payload pointing errors. In addition to Shuttle IMU attitude information, PAWS used atmospheric science sensors data to determine the spacecraft attitude. PAWS successfully achieved these goals by acquiring and processing data during the ATLAS 1, 2 mission. This paper presents the attitude determination algorithm real time processing, and results of post mission analysis. The findings of this study include the quality of the horizon sensor and IMU measurements as well as accuracy of attitude processor algorithm.

  4. Shoreline oiling from the Deepwater Horizon oil spill.

    PubMed

    Nixon, Zachary; Zengel, Scott; Baker, Mary; Steinhoff, Marla; Fricano, Gail; Rouhani, Shahrokh; Michel, Jacqueline

    2016-06-15

    We build on previous work to construct a comprehensive database of shoreline oiling exposure from the Deepwater Horizon (DWH) spill by compiling field and remotely-sensed datasets to support oil exposure and injury quantification. We compiled a spatial database of shoreline segments with attributes summarizing habitat, oiling category and timeline. We present new simplified oil exposure classes for both beaches and coastal wetland habitats derived from this database integrating both intensity and persistence of oiling on the shoreline over time. We document oiling along 2113km out of 9545km of surveyed shoreline, an increase of 19% from previously published estimates and representing the largest marine oil spill in history by length of shoreline oiled. These data may be used to generate maps and calculate summary statistics to assist in quantifying and understanding the scope, extent, and spatial distribution of shoreline oil exposure as a result of the DWH incident. PMID:27098990

  5. Near-horizon geometry and warped conformal symmetry

    NASA Astrophysics Data System (ADS)

    Afshar, Hamid; Detournay, Stéphane; Grumiller, Daniel; Oblak, Blagoje

    2016-03-01

    We provide boundary conditions for three-dimensional gravity including boosted Rindler spacetimes, representing the near-horizon geometry of non-extremal black holes or flat space cosmologies. These boundary conditions force us to make some unusual choices, like integrating the canonical boundary currents over retarded time and periodically identifying the latter. The asymptotic symmetry algebra turns out to be a Witt algebra plus a twisted u(1) current algebra with vanishing level, corresponding to a twisted warped CFT that is qualitatively different from the ones studied so far in the literature. We show that this symmetry algebra is related to BMS by a twisted Sugawara construction and exhibit relevant features of our theory, including matching micro- and macroscopic calculations of the entropy of zero-mode solutions. We confirm this match in a generalization to boosted Rindler-AdS. Finally, we show how Rindler entropy emerges in a suitable limit.

  6. Regenerative PN ranging experience with New Horizons during 2012

    NASA Astrophysics Data System (ADS)

    Jensen, J. R.; Haskins, C. B.; DeBoy, C. C.

    The New Horizons mission to Pluto is the first deep space mission to include the capability of supporting regenerative PN ranging. During the current phase of the mission, sequential tone ranging supports the mission navigation requirements but regenerative ranging will expand the conditions (antenna selection, integration time, etc.) over which ranging will be successful during any extended mission following the Pluto fly-by, to objects in the Kuiper belt. Experience with regenerative ranging is being obtained now in preparation for its use in an extended mission. During most of 2012, New Horizons was in a hibernation state. Tracking was conducted between late April and early July. Six regenerative ranging passes were performed to bookend this interval; 2 at the beginning and 4 at the end. During that time, the distance between the spacecraft and Earth was in excess of 22 Astronautical Units (AU) and the Pr/No levels were below 15 dB-Hz. A seventh regenerative ranging pass was performed in May at a higher signal level in order to test the acquisition of the ranging code by the spacecraft during a variety of conditions. The consistency of the regenerative range measurements with the adjacent sequential tone ranging measurements has been demonstrated and serves as a check on the calibration of the regenerative ranging system conditions. The range measurement precision has been shown to follow the predictions that are based on the uplink and downlink signal power. The regenerative ranging system has been shown to acquire the uplink ranging code with and without a commanded reset and regardless of the noise bandwidth setting of the system. This paper will present the data that was obtained during 2012 and will describe the analysis results for the regenerative ranging experience during 2012.

  7. Horizon sensors attitude errors simulation for the Brazilian Remote Sensing Satellite

    NASA Astrophysics Data System (ADS)

    Vicente de Brum, Antonio Gil; Ricci, Mario Cesar

    Remote sensing, meteorological and other types of satellites require an increasingly better Earth related positioning. From the past experience it is well known that the thermal horizon in the 15 micrometer band provides conditions of determining the local vertical at any time. This detection is done by horizon sensors which are accurate instruments for Earth referred attitude sensing and control whose performance is limited by systematic and random errors amounting about 0.5 deg. Using the computer programs OBLATE, SEASON, ELECTRO and MISALIGN, developed at INPE to simulate four distinct facets of conical scanning horizon sensors, attitude errors are obtained for the Brazilian Remote Sensing Satellite (the first one, SSR-1, is scheduled to fly in 1996). These errors are due to the oblate shape of the Earth, seasonal and latitudinal variations of the 15 micrometer infrared radiation, electronic processing time delay and misalignment of sensor axis. The sensor related attitude errors are thus properly quantified in this work and will, together with other systematic errors (for instance, ambient temperature variation) take part in the pre-launch analysis of the Brazilian Remote Sensing Satellite, with respect to the horizon sensor performance.

  8. Landsat-4 horizon scanner flight performance

    NASA Technical Reports Server (NTRS)

    Bilanow, S.; Chen, L. C.

    1984-01-01

    This paper presents an analysis of the flight data from a new design of horizon scanner flown on Landsat-4. The salient features in the data are described and demonstrated by data plots. High frequency noise must be filtered out to achieve good accuracy, but this is effectively done by 128-point averaging. Sun and moon interference effects are identified. The effects of earth oblateness and spacecraft altitude variations are modeled, and the residual systematic errors are analyzed. Most of the residual errors are apparently explained by the effects of earth radiance variation, with the winter polar regions showing the highest variability in the attitude measurements due to winter stratosphere temperature variations. In general, this sensor provides improved accuracy over those flown on previous missions.

  9. Black Hole Observations - Towards the Event Horizon

    NASA Astrophysics Data System (ADS)

    Britzen, Silke

    Black Holes are probably the most elusive solutions of Einstein's theory of General Relativity. Despite numerous observations of the direct galactic environment and indirect influence of astrophysical black holes (e.g. jets, variable emission across the wavelength spectrum, feedback processes, etc.) -- a direct proof of their existence is still lacking. This article highlights some aspects deduced from many observations and concentrates on the experimental results with regard to black holes with masses from millions to billions of solar masses. The focus will be on the challenges and remaining questions. The Event Horizon Telescopce (EHT) project to image the photon sphere of Sgr A* and its potential is briefly sketched. This instrumental approach shall lead to highest resolution observations of the supermassive black hole at the center of the Milky Way (Sgr A*).

  10. Horizon complementarity in elliptic de Sitter space

    NASA Astrophysics Data System (ADS)

    Hackl, Lucas; Neiman, Yasha

    2015-02-01

    We study a quantum field in elliptic de Sitter space dS4/Z2—the spacetime obtained from identifying antipodal points in dS4. We find that the operator algebra and Hilbert space cannot be defined for the entire space, but only for observable causal patches. This makes the system into an explicit realization of the horizon complementarity principle. In the absence of a global quantum theory, we propose a recipe for translating operators and states between observers. This translation involves information loss, in accordance with the fact that two observers see different patches of the spacetime. As a check, we recover the thermal state at the de Sitter temperature as a state that appears the same to all observers. This thermal state arises from the same functional that, in ordinary dS4, describes the Bunch-Davies vacuum.

  11. Opportunity Spies 'Endurance' on the Horizon

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image taken by the Mars Exploration Rover Opportunity's panoramic camera shows the eastern plains that stretch beyond the small crater where the rover landed. In the distance, the rim of a larger crater dubbed 'Endurance' can be seen.

    This color mosaic was taken on the 32nd martian day, or sol, of the rover's mission and spans 20 degrees of the horizon. It was taken while Opportunity was parked at the north end of the outcrop, in front of the rock region dubbed 'El Capitan' and facing east.

    The features seen at the horizon are the near and far rims of 'Endurance,' the largest crater within about 6 kilometers (4 miles) of the lander. Using orbital data from the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, scientists estimated the crater to be 160 meters (175 yards) in diameter, and about 720 meters (half a mile) away from the lander.

    The highest point visible on 'Endurance' is the highest point on the far wall of the crater; the sun is illuminating the inside of the far wall.

    Between the location where the image was taken at 'El Capitan' and 'Endurance' are the flat, smooth Meridiani plains, which scientists believe are blanketed in the iron-bearing mineral called hematite. The dark horizontal feature near the bottom of the picture is a small, five-meter (16-feet) crater, only 50 meters (164 feet) from Opportunity's present position. When the rover leaves the crater some 2 to 3 weeks from now, 'Endurance' is one of several potential destinations.

  12. Air-shower spectroscopy at horizons

    NASA Astrophysics Data System (ADS)

    Fargion, D.

    2006-07-01

    Downward cosmic rays are mostly revealed on the ground by their air-showers diluted and filtered secondary μμ traces and/or by their (Cerenkov - Fluorescent) light because of the high altitude numerous and luminous electromagnetic ee,γ shower component. Horizontal and upward air-showers are even more suppressed by deeper atmosphere opacity and by the Earth shadows. In such noise-free horizontal and upward directions rare Ultra High Cosmic rays and rarer neutrino induced air-showers may shine, mostly mediated by resonant PeV ν¯+e→W interactions in air or by higher energy tau air-showers originated by ν skimming the Earth. At high altitude (mountains, planes, balloons) the air density is so rarefied that nearly all common air-showers might be observed at their maximal growth at a tuned altitude and direction. The arrival angle samples different distances and the corresponding most probable primary cosmic ray energy. The larger and larger distances (between observer and C.R. interaction) make wider and wider the shower area and it enlarges the probability of being observed (up to three orders of magnitude more than vertical showers); the observation of a maximal electromagnetic shower development may amplify the signal by two three orders of magnitude (with respect to a suppressed shower at sea level); the peculiar altitude angle range (ten twenty km height and ≃80 90 zenith angle) may disentangle at best the primary cosmic ray energy and composition. Even from existing mountain observatories the up-going air-showers may trace, above the horizons, PeV EeV high energy cosmic rays and, below the horizons, PeV EeV neutrino astronomy: their early signals may be captured in already existing gamma telescopes such as Magic at Canarie, while facing the Earth edges during (useless) cloudy nights.

  13. THERMAL CONDUCTIVITY OF THE POTENTIAL REPOSITORY HORIZON

    SciTech Connect

    J.E. BEAN

    2004-09-27

    The primary purpose of this report is to assess the spatial variability and uncertainty of bulk thermal conductivity in the host horizon for the repository at Yucca Mountain. More specifically, the lithostratigraphic units studied are located within the Topopah Spring Tuff (Tpt) and consist of the upper lithophysal zone (Tptpul), the middle nonlithophysal zone (Tptpmn), the lower lithophysal zone (Tptpll), and the lower nonlithophysal zone (Tptpln). Design plans indicate that approximately 81 percent of the repository will be excavated in the Tptpll, approximately 12 percent in the Tptpmn, and the remainder in the Tptul and Tptpln (BSC 2004 [DIRS 168370]). This report provides three-dimensional geostatistical estimates of the bulk thermal conductivity for the four stratigraphic layers of the repository horizon. The three-dimensional geostatistical estimates of matrix and lithophysal porosity, dry bulk density, and matrix thermal conductivity are also provided. This report provides input to various models and calculations that simulate heat transport through the rock mass. These models include the ''Drift Degradation Analysis, Multiscale Thermohydrologic Model, Ventilation Model and Analysis Report, Igneous Intrusion Impacts on Waste Packages and Waste Forms, Drift-Scale Coupled Processes (DST and TH Seepage) Models'', and ''Drift Scale THM Model''. These models directly or indirectly provide input to the total system performance assessment (TSPA). The main distinguishing characteristic among the lithophysal and nonlithophysal units is the percentage of large-scale (centimeters-meters) voids within the rock. The Tptpul and Tptpll, as their names suggest, have a higher percentage of lithophysae than the Tptpmn and the Tptpln. Understanding the influence of the lithophysae is of great importance to understanding bulk thermal conductivity.

  14. New Horizons Risk Communication Strategy, Planning, Implementation, and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Dawson, Sandra A.

    2006-01-01

    This paper discusses the risk communication goals, strategy, planning process and product development for the New Horizons mission, including lessons from the Cassini mission that were applied in that effort, and presents lessons learned from the New Horizons effort that could be applicable to future missions.

  15. The Horizon Report: 2010 Australia-New Zealand Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Smith, R.; Levine, A.; Haywood, K.

    2010-01-01

    The internationally recognized series of "Horizon Reports" is part of the New Media Consortium's Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming five years on a variety of sectors around the globe. This volume, the "2010 Horizon…

  16. The NMC Horizon Report: 2013 Higher Education Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Cummins, M.; Estrada, V.; Freeman, A.; Ludgate, H.

    2013-01-01

    The internationally recognized "NMC Horizon Report" series and regional "NMC Technology Outlooks" are part of the NMC Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming five years in education around the globe.…

  17. The NMC Horizon Report: 2013 K-12 Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Cummins, M.; Estrada V.; Freeman, A.; Ludgate, H.

    2013-01-01

    "The NMC Horizon Report" series is the most visible outcome of the New Media Consortium (NMC) Horizon Project, an ongoing research effort established in 2002 that identifies and describes emerging technologies likely to have a large impact on teaching, learning, research, or creative expression within education around the globe. This…

  18. The NMC Horizon Report: 2012 Higher Education Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams, S.; Cummins, M.

    2012-01-01

    The internationally recognized "NMC Horizon Report" series and regional "NMC Technology Outlooks" are part of the NMC Horizon Project, a comprehensive research venture established in 2002 that identifies and describes emerging technologies likely to have a large impact over the coming five years in education around the globe. This volume, the "NMC…

  19. A Fusion of Horizons: Students' Encounters with "Will and Wave"

    ERIC Educational Resources Information Center

    Myers, James L.

    2006-01-01

    In a case study, I applied philosophical hermeneutic principles in an advanced level EFL writing class in Taiwan. A "fusion of horizons" occurs at the junction of two intertwined interpretations: one from our socio-historical tradition and the other from our experience of novel phenomena. I explored students' hermeneutic horizons in relation to…

  20. The NMC Horizon Report: 2011 K-12 Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams, S.; Haywood, K.

    2011-01-01

    "The NMC Horizon Report" series is the most visible outcome of the New Media Consortium. (NMC) Horizon Project, an ongoing research effort established in 2002 that identifies and describes emerging technologies likely to have a large impact on teaching, learning, research, or creative expression within education around the globe. This volume, "The…

  1. NEW JERSEY APPROACH TO OUTERBRIDGE CROSSING BRIDGE, NOTE DISTANT HORIZON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NEW JERSEY APPROACH TO OUTERBRIDGE CROSSING BRIDGE, NOTE DISTANT HORIZON NEW YORK SKYLINE AND ALMOST IN THE MIDDLE OF THE HORIZON THE TWIN TOWERS OF THE VERRAZANO-NARROWS BRIDGE - Outerbridge Crossing Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

  2. The NMC Horizon Report: 2015 Higher Education Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Estrada, V.; Freeman, A.

    2015-01-01

    The "NMC Horizon Report: 2015 Higher Education Edition" is a collaborative effort between the New Media Consortium (NMC) and the EDUCAUSE Learning Initiative (ELI). This 12th edition describes annual findings from the NMC Horizon Project, an ongoing research project designed to identify and describe emerging technologies likely to have…

  3. The NMC Horizon Report: 2014 K-12 Edition

    ERIC Educational Resources Information Center

    Johnson, L.; Adams Becker, S.; Estrada, V.; Freeman, A.

    2014-01-01

    "The NMC Horizon Report" series is the most visible outcome of the New Media Consortium (NMC) Horizon Project, an ongoing research effort established in 2002 that identifies and describes emerging technologies likely to have a large impact on teaching, learning, research, or creative expression within every sector of education in some 65…

  4. Fluctuations in horizon-fluid lead to negative bulk viscosity

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Swastik; Shankaranarayanan, S.

    2016-03-01

    Einstein equations projected on to a black-hole horizon give rise to Navier-Stokes equations. Horizon-fluids typically possess unusual features like negative bulk viscosity, and it is not clear whether a statistical-mechanical description exists for such fluids. In this work, we provide an explicit derivation of the Bulk viscosity of the horizon-fluid based on the theory of fluctuations à la Kubo. The main advantage of our approach is that our analysis remains for the most part independent of the details of the underlying microscopic theory and hence the conclusions reached here are model independent. We show that the coefficient of bulk viscosity for the horizon-fluid matches exactly with the value found from the equations of motion for the horizon-fluid.

  5. Observations of the Geometry of Horizon-Based Optical Navigation

    NASA Technical Reports Server (NTRS)

    Christian, John; Robinson, Shane

    2016-01-01

    NASA's Orion Project has sparked a renewed interest in horizon-based optical navigation(OPNAV) techniques for spacecraft in the Earth-Moon system. Some approaches have begun to explore the geometry of horizon-based OPNAV and exploit the fact that it is a conic section problem. Therefore, the present paper focuses more deeply on understanding and leveraging the various geometric interpretations of horizon-based OPNAV. These results provide valuable insight into the fundamental workings of OPNAV solution methods, their convergence properties, and associated estimate covariance. Most importantly, the geometry and transformations uncovered in this paper lead to a simple and non-iterative solution to the generic horizon-based OPNAV problem. This represents a significant theoretical advancement over existing methods. Thus, we find that a clear understanding of geometric relationships is central to the prudent design, use, and operation of horizon-based OPNAV techniques.

  6. Horizon of quantum black holes in various dimensions

    NASA Astrophysics Data System (ADS)

    Casadio, Roberto; Cavalcanti, Rogerio T.; Giugno, Andrea; Mureika, Jonas

    2016-09-01

    We adapt the horizon wave-function formalism to describe massive static spherically symmetric sources in a general (1 + D)-dimensional space-time, for D > 3 and including the D = 1 case. We find that the probability PBH that such objects are (quantum) black holes behaves similarly to the probability in the (3 + 1) framework for D > 3. In fact, for D ≥ 3, the probability increases towards unity as the mass grows above the relevant D-dimensional Planck scale mD. At fixed mass, however, PBH decreases with increasing D, so that a particle with mass m ≃mD has just about 10% probability to be a black hole in D = 5, and smaller for larger D. This result has a potentially strong impact on estimates of black hole production in colliders. In contrast, for D = 1, we find the probability is comparably larger for smaller masses, but PBH < 0.5, suggesting that such lower dimensional black holes are purely quantum and not classical objects. This result is consistent with recent observations that sub-Planckian black holes are governed by an effective two-dimensional gravitation theory. Lastly, we derive Generalised Uncertainty Principle relations for the black holes under consideration, and find a minimum length corresponding to a characteristic energy scale of the order of the fundamental gravitational mass mD in D > 3. For D = 1 we instead find the uncertainty due to the horizon fluctuations has the same form as the usual Heisenberg contribution, and therefore no fundamental scale exists.

  7. The Deepwater Horizon Disaster: What Happened and Why

    SciTech Connect

    Horne, Roland N.

    2011-01-05

    The Deepwater Horizon disaster was the largest oil spill in US history, and the second largest spill in the world. 11 men lost their lives in the explosion and fire. Although the impacts of the spill were evident to large numbers of people, its causes were harder to see. This lecture will focus on the technical aspects of the events that led to the spill itself: what happened on the rig before, during and after the event, up to the time the rig sank. As with many engineering disasters, the accident was due to a sequence of failures, including both technical systems and procedural issues. Although the causes were complex and interacting, the lecture will focus on four main problems: (1) the failure of the cement and casing seal, (2) the failure to recognize and respond to hydrocarbon flow into the riser, (3) the ignition of hydrocarbons on the rig, and (4) the failure of the blow-out preventer (BOP) to seal the well. The lecture will conclude with some suggestions as to how events such as the Deepwater Horizon disaster can be avoided in the future. (Roland N. Horne is the Thomas Davies Barrow Professor of Earth Sciences at Stanford University, and was the Chairman of Petroleum Engineering from 1995 to 2006. He holds BE, PhD and DSc degrees from the University of Auckland, New Zealand, all in Engineering Science. Horne is a member of the U.S. National Academy of Engineering and is also an Honorary Member of the Society of Petroleum Engineers.)

  8. Horizon sensor errors calculated by computer models compared with errors measured in orbit

    NASA Technical Reports Server (NTRS)

    Ward, K. A.; Hogan, R.; Andary, J.

    1982-01-01

    Using a computer program to model the earth's horizon and to duplicate the signal processing procedure employed by the ESA (Earth Sensor Assembly), errors due to radiance variation have been computed for a particular time of the year. Errors actually occurring in flight at the same time of year are inferred from integrated rate gyro data for a satellite of the TIROS series of NASA weather satellites (NOAA-A). The predicted performance is compared with actual flight history.

  9. Horizon Sensor Errors Calculated By Computer Models Compared With Errors Measured In Orbit

    NASA Astrophysics Data System (ADS)

    Ward, Kenneth A.; Hogan, Roger; Andary, James

    1982-06-01

    Using a computer program to model the earth's horizon and to duplicate the signal processing procedure employed by the ESA (Earth Sensor Assembly), errors due to radiance variation have been computed for a particular time of the year. Errors actually occurring in flight at the same time of year are inferred from integrated rate gyro data for a satellite of the TIROS series of NASA weather satellites (NOAA-7). The k)recLicted performance is compared with actual flight history.

  10. Earthquake Precursors An Example of Data Acquisition and Processing at Science Horizons

    NASA Astrophysics Data System (ADS)

    Cherry, J. T.

    2007-12-01

    Science Horizons has used COTS products, namely its AQUINAS® System and SeismicRadar®, to identify earthquake precursors from seismic data 1,000 miles from the earthquake's epicenter. We have assumed that a precursor has the same characteristics, specifically the same azimuth and horizontal phase velocity, as the earthquake's P-wave. In addition, we have also shown the superiority of seismic arrays to detect precursors. The precursors identified by SeismicRadar® preceded the earthquakes with times ranging from thirteen hours to one minute. Therefore, one can conclude that the same assumption and the same technology should be able to detect numerous precursors that are a few miles from a pending earthquake's epicenter. If this conclusion is shown to be valid in seismic areas, earthquake precursors will no longer be elusive. Then we will be able to create algorithms, based on the precursor's location, duration, and frequency, that reliably predict earthquakes. Science Horizons has a patent pending on this earthquake prediction method. For more information regarding Science Horizons' earthquake prediction method, please go to our website at http://www.horizon.com .

  11. Multiple microtektite horizons in upper Eocene marine sediments: No evidence for mass extinctions

    USGS Publications Warehouse

    Keller, G.; D'Hondt, S.; Vallier, T.L.

    1983-01-01

    Microtektites have been recovered from three horizons in eight middle Eocene to middle Oligocene marine sediment sequences. Five of these occurrences are coeval and of latest Eocene age (37.5 to 38.0 million years ago); three are coeval and of early late Eocene age (38.5 to 39.5 million years ago); and three are of middle Oligocene age (31 to 32 million years ago). In addition, rare probable microtektites have been found in sediments with ages of about 36.0 to 36.5 million years. The microtektite horizon at 37.5 to 38.0 million years can be correlated with the North American tektite-strewn field, which has a fission track age (minimum) of 34 to 35 million years and a paleomagnetic age of 37.5 to 38.0 million years. There is no evidence for mass faunal extinctions at any of the microtektite horizons. Many of the distinct faunal changes that occurred in the middle Eocene to middle Oligocene can be related to the formation of the Antarctic ice sheet and the associated cooling phenomena and intensification of bottom currents that led to large-scale dissolution of calcium carbonate and erosion, which created areally extensive hiatuses in the deep-sea sediment records. The occurrence of microtektite horizons of several ages and the lack of evidence for faunal extinctions suggest that the effects of extraterrestrial bolide impacts may be unimportant in the biologic realm during middle Eocene to middle Oligocene time.

  12. New Horizons mission to Pluto and the Kuiper belt

    NASA Astrophysics Data System (ADS)

    McKinnon, W.; Stern, S.; Weaver, H.; Young, L.; Olkin, C.; New Horizons Science Team

    2014-07-01

    two 30--50 kilometer-diameter Kuiper Belt Objects (KBOs) if 1) the spacecraft is in good health, 2) at least one accessible KBO can be located from the Earth or Earth orbit in time, and 3) NASA approves an extended mission. New Horizons previously conducted a successful encounter with Jupiter and the Galilean satellites, has collected and is collecting valuable cruise science data, and became the prototype for NASA's medium-scale, PI-led New Frontiers planetary mission class. The NH flyby of the Pluto system will represent a watershed in the scientific exploration of the Solar System, by exploring a new class of planet in the Solar System --- dwarf planets --- and an accompanying, extensive satellite system. In this review talk we provide a more in-depth overview of the spacecraft, payload, and flyby plans.

  13. 76 FR 55427 - Horizon Technology Finance Corporation, et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... COMMISSION Horizon Technology Finance Corporation, et al.; Notice of Application August 31, 2011. AGENCY...(a) of the Act. Applicants: Horizon Technology Finance Corporation (the ``Company''), Horizon Technology Finance Management LLC (the ``Investment Adviser''), Longview SBIC GP LLC (the ``General...

  14. Horizon shells and BMS-like soldering transformations

    NASA Astrophysics Data System (ADS)

    Blau, Matthias; O'Loughlin, Martin

    2016-03-01

    We revisit the theory of null shells in general relativity, with a particular emphasis on null shells placed at horizons of black holes. We study in detail the considerable freedom that is available in the case that one solders two metrics together across null hypersurfaces (such as Killing horizons) for which the induced metric is invariant under translations along the null generators. In this case the group of soldering transformations turns out to be infinite dimensional, and these solderings create non-trivial horizon shells containing both massless matter and impulsive gravitational wave components. We also rephrase this result in the language of Carrollian symmetry groups. To illustrate this phenomenon we discuss in detail the example of shells on the horizon of the Schwarzschild black hole (with equal interior and exterior mass), uncovering a rich classical structure at the horizon and deriving an explicit expression for the general horizon shell energy-momentum tensor. In the special case of BMS-like soldering supertranslations we find a conserved shell-energy that is strikingly similar to the standard expression for asymptotic BMS supertranslation charges, suggesting a direct relation between the physical properties of these horizon shells and the recently proposed BMS supertranslation hair of a black hole.

  15. Physical process first law for bifurcate Killing horizons

    SciTech Connect

    Amsel, Aaron J.; Marolf, Donald; Virmani, Amitabh

    2008-01-15

    The physical process version of the first law for black holes states that the passage of energy and angular momentum through the horizon results in a change in area ({kappa}/8{pi}){delta}A={delta}E-{omega}{delta}J, so long as this passage is quasistationary. A similar physical process first law can be derived for any bifurcate Killing horizon in any spacetime dimension d{>=}3 using much the same argument. However, to make this law nontrivial, one must show that sufficiently quasistationary processes do in fact occur. In particular, one must show that processes exist for which the shear and expansion remain small, and in which no new generators are added to the horizon. Thorne, MacDonald, and Price considered related issues when an object falls across a d=4 black hole horizon. By generalizing their argument to arbitrary d{>=}3 and to any bifurcate Killing horizon, we derive a condition under which these effects are controlled and the first law applies. In particular, by providing a nontrivial first law for Rindler horizons, our work completes the parallel between the mechanics of such horizons and those of black holes for d{>=}3. We also comment on the situation for d=2.

  16. Lunar horizon glow and the Clementine mission

    NASA Technical Reports Server (NTRS)

    Zook, H. A.; Potter, A. E.

    1994-01-01

    The Clementine spacecraft is to be launched into Earth orbit in late January for subsequent insertion into lunar orbit in late February, 1994. There, its primary mission is to produce -- over a period of about two months -- a new photographic map of the entire surface of the Moon; this will be done, in a variety of wavelengths and spatial resolutions, in a manner greatly superior to that previously accomplished for the whole Moon. It will then go on to fly by and photograph the asteroid Geographos. A secondary goal that has been accepted for this mission is to take a series of photographs designed to capture images of, and determine the brightness and extent of, the Lunar Horizon Glow (LHG). One form of LHG is caused by the solar stimulation of emission from Na and K atoms in the lunar exosphere. The scale height of this exosphere is of the order of 100 km. There are also brighter LHG components, with much smaller scale heights, that appear to be caused by scattered off of an exospheric lunar dust cloud.

  17. Perturbative string thermodynamics near black hole horizons

    NASA Astrophysics Data System (ADS)

    Mertens, Thomas G.; Verschelde, Henri; Zakharov, Valentin I.

    2015-06-01

    We provide further computations and ideas to the problem of near-Hagedorn string thermodynamics near (uncharged) black hole horizons, building upon our earlier work [1]. The relevance of long strings to one-loop black hole thermodynamics is emphasized. We then provide an argument in favor of the absence of α'-corrections for the (quadratic) heterotic thermal scalar action in Rindler space. We also compute the large k limit of the cigar orbifold partition functions (for both bosonic and type II superstrings) which allows a better comparison between the flat cones and the cigar cones. A discussion is made on the general McClain-Roth-O'Brien-Tan theorem and on the fact that different torus embeddings lead to different aspects of string thermodynamics. The black hole/string correspondence principle for the 2d black hole is discussed in terms of the thermal scalar. Finally, we present an argument to deal with arbitrary higher genus partition functions, suggesting the breakdown of string perturbation theory (in g s ) to compute thermodynam-ical quantities in black hole spacetimes.

  18. Large Dust Devil on Horizon, Sol 468

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This movie clip shows a large, distant dust devil -- a whirlwind that lofts dust into the air -- as a dark shape on the horizon near the right side of the images. This dust devil was about 5 kilometers (3 miles) away from NASA's Mars Exploration Rover Spirit, and may have been up to 200 meters or yards in diameter. Smaller dust devils closer to the rover appear bright against the dark ground. Spirit's navigation camera took these images on the rover's 468th martian day, or sol (April 27, 2005.) Contrast has been enhanced for anything in the images that changes from frame to frame, that is, for the dust devil. The number of seconds elapsed since the first frame is indicated at lower left of the images, typically 20 seconds between frames.

    Scientists expected dust devils since before Spirit landed. The landing area inside Gusev Crater is filled with dark streaks left behind when dust devils pick dust up from an area. It is also filled with bright 'hollows,' which are dust-filled miniature craters. Dust covers most of the terrain. Winds flow into and out of Gusev crater every day. The Sun heats the surface so that the surface is warm to the touch even though the atmosphere at 2 meters (6 feet) above the surface would be chilly. That temperature contrast causes convection. Mixing the dust, winds, and convection can trigger dust devils.

  19. LANDSAT-4 horizon scanner performance evaluation

    NASA Technical Reports Server (NTRS)

    Bilanow, S.; Chen, L. C.; Davis, W. M.; Stanley, J. P.

    1984-01-01

    Representative data spans covering a little more than a year since the LANDSAT-4 launch were analyzed to evaluate the flight performance of the satellite's horizon scanner. High frequency noise was filtered out by 128-point averaging. The effects of Earth oblateness and spacecraft altitude variations are modeled, and residual systematic errors are analyzed. A model for the predicted radiance effects is compared with the flight data and deficiencies in the radiance effects modeling are noted. Correction coefficients are provided for a finite Fourier series representation of the systematic errors in the data. Analysis of the seasonal dependence of the coefficients indicates the effects of some early mission problems with the reference attitudes which were computed by the onboard computer using star trackers and gyro data. The effects of sun and moon interference, unexplained anomalies in the data, and sensor noise characteristics and their power spectrum are described. The variability of full orbit data averages is shown. Plots of the sensor data for all the available data spans are included.

  20. Horizon scan of global conservation issues for 2011.

    PubMed

    Sutherland, William J; Bardsley, Sarah; Bennun, Leon; Clout, Mick; Côté, Isabelle M; Depledge, Michael H; Dicks, Lynn V; Dobson, Andrew P; Fellman, Liz; Fleishman, Erica; Gibbons, David W; Impey, Andrew J; Lawton, John H; Lickorish, Fiona; Lindenmayer, David B; Lovejoy, Thomas E; Nally, Ralph Mac; Madgwick, Jane; Peck, Lloyd S; Pretty, Jules; Prior, Stephanie V; Redford, Kent H; Scharlemann, Jörn P W; Spalding, Mark; Watkinson, Andrew R

    2011-01-01

    This review describes outcomes of a 2010 horizon-scanning exercise building upon the first exercise conducted in 2009. The aim of both horizon scans was to identify emerging issues that could have substantial impacts on the conservation of biological diversity, and to do so sufficiently early to encourage policy-relevant, practical research on those issues. Our group included professional horizon scanners and researchers affiliated with universities and non- and inter-governmental organizations, including specialists on topics such as invasive species, wildlife diseases and coral reefs. We identified 15 nascent issues, including new greenhouse gases, genetic techniques to eradicate mosquitoes, milk consumption in Asia and societal pessimism. PMID:21126797

  1. Micromorphometric features of pore space in the plow horizons of loamy soils

    NASA Astrophysics Data System (ADS)

    Skvortsova, E. B.; Sanzharova, S. I.

    2007-04-01

    A computer-based analysis of thin sections has been applied to study pore space in the plow horizons of loamy soils in European Russia and Ukraine. Differences in the morphology of soil macro-and mesopores are shown. It is argued that agrogenic impacts result in the convergence of the shape and orientation of macropores in plowed loamy soils of the forest, forest-steppe, and steppe zones. At the same time, this convergence is not observed for the soil mesopores.

  2. "Far Horizons" -- Near-space Exploration At The Adler Planetarium

    NASA Astrophysics Data System (ADS)

    Hammergren, Mark; Gyuk, G.; Friedman, R. B.

    2011-01-01

    Over the past four years, the Adler Planetarium has developed a diverse suite of educational activities involving hands-on scientific exploration via our "Far Horizons" high-altitude ballooning program. These efforts largely have been focused on increasing excitement and motivation for learning outside of school time, and include middle school summer camps, a high school summer program (the Astro-Science Workshop), school-year internships for high school students, summer internships for undergraduates, a NSF-funded graduate fellowship, and an active public volunteer program. In 2010, our programs were dedicated to the memory of renowned Chicago adventurer and explorer Steve Fossett. In 2011, in continued tribute to Steve Fossett, we further expand our out-of-school time programs with a summer workshop designed to enable high school teachers to form and advise student high-altitude ballooning clubs. This model program will be developed as one element of our ongoing partnership with the Air Force Academy High School in Chicago. This material is based in part upon work supported by the National Science Foundation under Grant No. 0525995.

  3. Testing General Relativity with the Event Horizon Telescope

    NASA Astrophysics Data System (ADS)

    Benkevitch, Leonid; Fish, V. L.; Johannsen, T.; Akiyama, K.; Broderick, A. E.; Psaltis, D.; Doeleman, S.; Monnier, J. D.; Baron, F.

    2013-01-01

    Strong gravitational lensing of light near black holes is one of the effects predicted by general relativity (GR). Emission close to a black hole will typically be lensed to illuminate the last photon orbit, creating a feature known as the black hole 'shadow' or 'silhouette'. The precise size and shape of the shadow is dependent on black hole mass, spin, and the space-time metric. The Event Horizon Telescope (EHT) is a (sub)mm VLBI network that can achieve Schwarzschild Radius scale resolution on SgrA*, the 4 million solar mass black hole at the Galactic Center. Here we present initial studies of how recent and future EHT observations of SgrA* can be used to test the No-Hair theorem by searching for deviations from the expected shadow morphology. We have developed a pipeline for producing synthetic EHT data sets from black hole emission models using perturbed space-time metrics that violate the No-Hair theorem. Employing imaging and modelfitting algorithms tailored for EHT data, we extract parameters of the black hole shadow. Preliminary results indicate that the EHT can provide a new way to test GR in the strong gravity regime that is complementary to techniques in other fields.

  4. Complementary and Alternative Medicine (CAM): Expanding Horizons of Health Care

    MedlinePlus

    ... Past Issues Special Section CAM Expanding Horizons of Health Care Past Issues / Winter 2009 Table of Contents For ... and why it is important to tell your health care providers about your use of CAM. We hope ...

  5. Entanglement entropy of a black hole and isolated horizon

    NASA Astrophysics Data System (ADS)

    Shi, Jianhua; Hu, Shuangqi; Zhao, Ren

    2013-02-01

    Using Unruh-Verlinde temperature obtained by entropic force, we directly calculate partition functions of quantum field in Schwarzschild spacetime via quantum statistical method and derive the expression of the black hole statistical entropy. In our calculation the lower limit of integral is the location of isolated horizon introduced in loop quantum gravity and the upper limit of integral is infinity. So the obtained entropy is the statistical entropy from isolated horizon to the infinite. In our calculation there are not the cutoff and approximation. The results showed that, as long as proper Immirzi parameters are selected, the entropy obtained by loop quantum gravity is consistent with the quantum statistical entropy outside the black hole horizon. Therefore the black hole entropy is a quantum entanglement entropy outside the isolated horizon.

  6. Note on electrical and thermodynamic properties of isolated horizons

    NASA Astrophysics Data System (ADS)

    Chen, Gerui; Wu, Xiaoning; Gao, Sijie

    2015-03-01

    The electrical laws and Carnot cycle of isolated horizons (IH) are investigated in this paper. We establish Ohm's law and Joule's law of isolated horizons and find that the conceptual picture of black holes (membrane paradigm) can also apply to this kind of quasilocal black holes. We also investigate the geometrical properties near nonrotating IHs and find that under the first-order approximation of r , there exist a Killing vector ∂∂u/ and a Hamiltonian conjugate to it, so this vector can be thought to be a physical observer. We calculate the energy as measured at infinity of a particle at rest outside a nonrotating IH, and we use this result to construct a reversible Carnot cycle with the isolated horizon as a cold reservoir, which confirms the thermodynamic nature of isolated horizons.

  7. JERSEY APPROACH VIADUCT LOOKING EAST, NOTE VERRAZANO TOWERS ON HORIZON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    JERSEY APPROACH VIADUCT LOOKING EAST, NOTE VERRAZANO TOWERS ON HORIZON TO LEFT - Goethals Bridge, Spanning Arthur Kill from New Jersey to Staten Island, Staten Island (subdivision), Richmond County, NY

  8. Universal properties of the near-horizon optical geometry

    NASA Astrophysics Data System (ADS)

    Gibbons, G. W.; Warnick, C. M.

    2009-03-01

    Making use of the fact that the optical geometry near a static nondegenerate Killing horizon is asymptotically hyperbolic, we investigate some universal features of black-hole horizons. Applying the Gauss-Bonnet theorem allows us to establish some general properties of gravitational lensing, valid for all black holes. Hyperbolic geometry allows us to find rates for the loss of scalar, vector, and fermionic “hair” as objects fall quasistatically towards the horizon, extending previous results for Schwarzschild to all static Killing horizons. In the process we find the Liénard-Wiechert potential for hyperbolic space and calculate the force between electrons mediated by neutrinos, extending the flat space result of Feinberg and Sucher. We further demonstrate how these techniques allow us to derive the exact Copson-Linet potential due to a point charge in a Schwarzschild background in a simple fashion.

  9. The Cauchy horizon singularity inside Kerr black holes

    NASA Astrophysics Data System (ADS)

    Burko, Lior M.; Khanna, Gaurav

    2016-03-01

    The numerical technology that allows for the careful evolution of linearized fields inside Kerr black holes and the study of their behavior approaching the Cauchy horizon singularity includes a number of interesting aspects. The latter include compactified hyperboloidal coordinates and foliation, mixed type hyperbolic-elliptic PDE, and initial data evolution where all equal-coordinate hypersurfaces are spacelike. We review the need for the numerical technology that allows for the solution of the spin-2 Teukolsky equation inside Kerr black holes, and discuss the main features thereof. We present new results about the numerical properties of the Cauchy horizon singularity and their correspondence with the predictions of perturbative analysis. We then discuss present directions of study, which include the sub-dominant azimuthal modes, approaching the Cauchy horizon singularity along timelike directions, approaching the Marolf-Ori (``outflying'') singularity and the studying the fields along the Cauchy horizon.

  10. Universal properties of the near-horizon optical geometry

    SciTech Connect

    Gibbons, G. W.; Warnick, C. M.

    2009-03-15

    Making use of the fact that the optical geometry near a static nondegenerate Killing horizon is asymptotically hyperbolic, we investigate some universal features of black-hole horizons. Applying the Gauss-Bonnet theorem allows us to establish some general properties of gravitational lensing, valid for all black holes. Hyperbolic geometry allows us to find rates for the loss of scalar, vector, and fermionic ''hair'' as objects fall quasistatically towards the horizon, extending previous results for Schwarzschild to all static Killing horizons. In the process we find the Lienard-Wiechert potential for hyperbolic space and calculate the force between electrons mediated by neutrinos, extending the flat space result of Feinberg and Sucher. We further demonstrate how these techniques allow us to derive the exact Copson-Linet potential due to a point charge in a Schwarzschild background in a simple fashion.

  11. Cutoffs, stretched horizons, and black hole radiators

    NASA Astrophysics Data System (ADS)

    Kaloper, Nemanja

    2012-11-01

    We argue that if the UV cutoff of an effective field theory with many low energy degrees of freedom is of the order, or below, the scale of the stretched horizon in a black hole background, which in turn is significantly lower than the Planck scale, the black hole radiance rate may not be enhanced by the emission of all the light IR modes. Instead, there may be additional suppressions hidden in the UV completion of the field theory, which really control which light modes can be emitted by the black hole. It could turn out that many degrees of freedom cannot be efficiently emitted by the black hole, and so the radiance rate may be much smaller than its estimate based on the counting of the light IR degrees of freedom. If we apply this argument to the Randall-Sundrum II (RS2) brane world, it implies that the emission rates of the low energy conformal field theory modes will be dramatically suppressed: its UV completion is given by the bulk gravity on AdS5×S5, and the only bulk modes which could be emitted by a black hole are the 4-dimensional (4D) s waves of bulk modes with small 5-dimensional momentum, or equivalently, small 4D masses. Further, their emission is suppressed by bulk warping, which lowers the radiation rate much below the IR estimate, yielding a radiation flux ˜(TBHL)2LHawking˜(TBH/MPl)2NLHawking, where LHawking is the Hawking radiation rate of a single light species. This follows directly from low conformal field theory cutoff μ˜L-1≪MPl, a large number of modes N≫1 and the fact that 4D gravity in RS2 is induced, MPl2≃Nμ2.

  12. Output-feedback control of combined sewer networks through receding horizon control with moving horizon estimation

    NASA Astrophysics Data System (ADS)

    Joseph-Duran, Bernat; Ocampo-Martinez, Carlos; Cembrano, Gabriela

    2015-10-01

    An output-feedback control strategy for pollution mitigation in combined sewer networks is presented. The proposed strategy provides means to apply model-based predictive control to large-scale sewer networks, in-spite of the lack of measurements at most of the network sewers. In previous works, the authors presented a hybrid linear control-oriented model for sewer networks together with the formulation of Optimal Control Problems (OCP) and State Estimation Problems (SEP). By iteratively solving these problems, preliminary Receding Horizon Control with Moving Horizon Estimation (RHC/MHE) results, based on flow measurements, were also obtained. In this work, the RHC/MHE algorithm has been extended to take into account both flow and water level measurements and the resulting control loop has been extensively simulated to assess the system performance according different measurement availability scenarios and rain events. All simulations have been carried out using a detailed physically based model of a real case-study network as virtual reality.

  13. A horizon scan of global conservation issues for 2015.

    PubMed

    Sutherland, William J; Clout, Mick; Depledge, Michael; Dicks, Lynn V; Dinsdale, Jason; Entwistle, Abigail C; Fleishman, Erica; Gibbons, David W; Keim, Brandon; Lickorish, Fiona A; Monk, Kathryn A; Ockendon, Nancy; Peck, Lloyd S; Pretty, Jules; Rockström, Johan; Spalding, Mark D; Tonneijck, Femke H; Wintle, Bonnie C

    2015-01-01

    This paper presents the results of our sixth annual horizon scan, which aims to identify phenomena that may have substantial effects on the global environment, but are not widely known or well understood. A group of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics via an iterative, Delphi-like process. The topics include a novel class of insecticide compounds, legalisation of recreational drugs, and the emergence of a new ecosystem associated with ice retreat in the Antarctic. PMID:25433442

  14. Supertranslations and Superrotations at the Black Hole Horizon

    NASA Astrophysics Data System (ADS)

    Donnay, Laura; Giribet, Gaston; González, Hernán A.; Pino, Miguel

    2016-03-01

    We show that the asymptotic symmetries close to nonextremal black hole horizons are generated by an extension of supertranslations. This group is generated by a semidirect sum of Virasoro and Abelian currents. The charges associated with the asymptotic Killing symmetries satisfy the same algebra. When considering the special case of a stationary black hole, the zero mode charges correspond to the angular momentum and the entropy at the horizon.

  15. A horizon scan of global conservation issues for 2013.

    PubMed

    Sutherland, William J; Bardsley, Sarah; Clout, Mick; Depledge, Michael H; Dicks, Lynn V; Fellman, Liz; Fleishman, Erica; Gibbons, David W; Keim, Brandon; Lickorish, Fiona; Margerison, Ceri; Monk, Kathryn A; Norris, Kenneth; Peck, Lloyd S; Prior, Stephanie V; Scharlemann, Jörn P W; Spalding, Mark D; Watkinson, Andrew R

    2013-01-01

    This paper presents the findings of our fourth annual horizon-scanning exercise, which aims to identify topics that increasingly may affect conservation of biological diversity. The 15 issues were identified via an iterative, transferable process by a team of professional horizon scanners, researchers, practitioners, and a journalist. The 15 topics include the commercial use of antimicrobial peptides, thorium-fuelled nuclear power, and undersea oil production. PMID:23219597

  16. Supertranslations and Superrotations at the Black Hole Horizon.

    PubMed

    Donnay, Laura; Giribet, Gaston; González, Hernán A; Pino, Miguel

    2016-03-01

    We show that the asymptotic symmetries close to nonextremal black hole horizons are generated by an extension of supertranslations. This group is generated by a semidirect sum of Virasoro and Abelian currents. The charges associated with the asymptotic Killing symmetries satisfy the same algebra. When considering the special case of a stationary black hole, the zero mode charges correspond to the angular momentum and the entropy at the horizon. PMID:26991167

  17. Optical Navigation Preparations for New Horizons Pluto Flyby

    NASA Technical Reports Server (NTRS)

    Owen, William M., Jr.; Dumont, Philip J.; Jackman, Coralie D.

    2012-01-01

    The New Horizons spacecraft will encounter Pluto and its satellites in July 2015. As was the case for the Voyager encounters with Jupiter, Saturn, Uranus and Neptune, mission success will depend heavily on accurate spacecraft navigation, and accurate navigation will be impossible without the use of pictures of the Pluto system taken by the onboard cameras. We describe the preparations made by the New Horizons optical navigators: picture planning, image processing algorithms, software development and testing, and results from in-flight imaging.

  18. Thermodynamics of cosmological horizons in f(T) gravity

    SciTech Connect

    Bamba, Kazuharu; Geng, Chao-Qiang E-mail: geng@phys.nthu.edu.tw

    2011-11-01

    We explore thermodynamics of the apparent horizon in f(T) gravity with both equilibrium and non-equilibrium descriptions. We find the same dual equilibrium/non-equilibrium formulation for f(T) as for f(R) gravity. In particular, we show that the second law of thermodynamics can be satisfied for the universe with the same temperature outside and inside the apparent horizon.

  19. Runge-Kutta Discretizations of Infinite Horizon Optimal Control Problems with Steady-State Invariance

    NASA Astrophysics Data System (ADS)

    Diele, F.; Marangi, C.; Ragni, S.

    2009-08-01

    Direct numerical approximation of a continuous-time infinite horizon control problem, requires to recast the model as a discrete-time, finite-horizon control model. The quality of the optimization results can be heavily degraded if the discretization process does not take into account features of the original model to be preserved. Restricting their attention to optimal growh problems with a steady state, Mercenier and Michel in [1] and [2], studied the conditions to be imposed for ensuring that discrete first-order approximation models have the same steady states as the infinite-horizon continuous-times counterpart. Here we show that Mercenier and Michel scheme is a first order partitioned Runge-Kutta method applied to the state-costate differential system which arises from the Pontryagin maximum principle. The main consequence is that it is possible to consider high order schemes which generalize that algorithm by preserving the steady-growth invariance of the solutions with respect to the discretization process. Numerical examples show the efficiency and accuracy of the proposed methods when applied to the classical Ramsey growth model.

  20. Comparisons Between New Horizons Results and Long-Term Monitoring of Pluto

    NASA Astrophysics Data System (ADS)

    Buie, M. W.; Stern, A.; Young, L. A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.; Moore, J. M.; Grundy, W. M.

    2015-12-01

    The New Horizons encounter data have revealed a diverse and complicated surface and atmosphere for Pluto showing strong correlations between geologic features and the albedo and compositional units known from ground- and HST-based observations over the decades prior. This presentation will delve into detailed comparisons between the long time base and low spatial resolution data and the new high resolution snapshot of Pluto from the flyby. Special emphasis will be placed on the albedo and near-infrared spectral evolution over time. We will compare the albedo maps from the late 1980's built on mutual event data and two epochs of HST observations against the New Horizons images, after correcting for viewing geometry. Also included will be a discussion of the evolutionary trends in the hemispherically averaged spectral properties from Lowell Observatory and IRTF data against the resolved compositional and spectral maps from New Horizons. The combination of these data sets now permits an unprecedented ability to constrain time-variability on the surface from apparent changes due to viewing geometry and surface inhomogeneities. These comparisons require a reconcilliation of surface scattering properties that are enabled by the firm determination of the size of Pluto.

  1. Comparisons Between New Horizons Results and Long-Term Monitoring of Pluto

    NASA Astrophysics Data System (ADS)

    Buie, M. W.; Stern, A.; Young, L. A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.; Moore, J. M.; Grundy, W. M.

    2014-12-01

    The New Horizons encounter data have revealed a diverse and complicated surface and atmosphere for Pluto showing strong correlations between geologic features and the albedo and compositional units known from ground- and HST-based observations over the decades prior. This presentation will delve into detailed comparisons between the long time base and low spatial resolution data and the new high resolution snapshot of Pluto from the flyby. Special emphasis will be placed on the albedo and near-infrared spectral evolution over time. We will compare the albedo maps from the late 1980's built on mutual event data and two epochs of HST observations against the New Horizons images, after correcting for viewing geometry. Also included will be a discussion of the evolutionary trends in the hemispherically averaged spectral properties from Lowell Observatory and IRTF data against the resolved compositional and spectral maps from New Horizons. The combination of these data sets now permits an unprecedented ability to constrain time-variability on the surface from apparent changes due to viewing geometry and surface inhomogeneities. These comparisons require a reconcilliation of surface scattering properties that are enabled by the firm determination of the size of Pluto.

  2. Deformation of codimension-2 surfaces and horizon thermodynamics

    NASA Astrophysics Data System (ADS)

    Cao, Li-Ming

    2011-03-01

    The deformation equation of a spacelike submanifold with an arbitrary codimension is given by a general construction without using local frames. In the case of codimension-1, this equation reduces to the evolution equation of the extrinsic curvature of a spacelike hypersurface. In the more interesting case of codimension-2, after selecting a local null frame, this deformation equation reduces to the well known (cross) focusing equations. We show how the thermodynamics of trapping horizons is related to these deformation equations in two different formalisms: with and without introducing quasilocal energy. In the formalism with the quasilocal energy, the Hawking mass in four dimension is generalized to higher dimension, and it is found that the deformation of this energy inside a marginal surface can be also decomposed into the contributions from matter fields and gravitational radiation as in the four dimension. In the formalism without the quasilocal energy, we generalize the definition of slowly evolving future outer trapping horizons proposed by Booth to past trapping horizons. The dynamics of the trapping horizons in FLRW universe is given as an example. Especially, the slowly evolving past trapping horizon in the FLRW universe has close relation to the scenario of slow-roll inflation. Up to the second order of the slowly evolving parameter in this generalization, the temperature (surface gravity) associated with the slowly evolving trapping horizon in the FLRW universe is essentially the same as the one defined by using the quasilocal energy.

  3. Integrating horizon scanning and strategic risk prioritisation using a weight of evidence framework to inform policy decisions.

    PubMed

    Garnett, K; Lickorish, F A; Rocks, S A; Prpich, G; Rathe, A A; Pollard, S J T

    2016-08-01

    Poor connection between data on emerging issues and credible policy decisions continues to challenge governments, and is only likely to grow as demands on time and resources increase. Here we summarise recent efforts to integrate horizon scanning and risk prioritisation approaches to better connect emerging issues to the political discourse on environmental and food-related issues. Our categorisation of insights including potential future risks and opportunities to inform policy discussions has emerged from a structured three-year programme of horizon scanning for a UK pan-governmental futures partnership led by the Department for Environment, Food and Rural Affairs (Defra). Our efforts to integrate horizon scanning and risk prioritisation, utilising a qualitative weight of evidence framework, has created a systematic process for identifying all signals of potential future change with significant impact for the strategic mission and underlying values of policy actors. Our approach encourages an exploration of factors out of the control of organisations, recognising that resilience depends on the flexibility of management strategies and the preparedness to deal with a variety of unexpected outcomes. We discuss how this approach addresses key cultural and evaluative challenges that policy actors have had in embedding horizon scanning in evidence-based policy processes, and suggest further developments to build confidence in the use of horizon scanning for strategic planning. PMID:27093126

  4. Black Hole Event Horizons and Advection-Dominated Accretion

    NASA Technical Reports Server (NTRS)

    McClintock, Jeffrey; Mushotzky, Richard F. (Technical Monitor)

    2001-01-01

    The XMM data on black-hole X-ray novae are only now becoming available and they have so far not been included in any publications. This work is part of a larger project that makes use of both XMM and Chandra data. Our first publication on the Chandra results is the following: "New Evidence for Black Hole Event Horizons from Chandra" by M.R. Garcia, J.E. McClintock, R. Narayan, P. Callanan, D. Barret and S. Murray (2001, ApJ, 553, L47). Therein we present the luminosities of the two black-hole X-ray novae, GRO J0422+22 and 4U1 543-47, which were observed by Chandra. These results are combined with the luminosities of four additional black-hole X-ray novae, which were observed as part of a Chandra GTO program (PI: S. Murray). The very low, but nonzero, quiescent X-ray luminosities of these black hole binaries is very difficult to understand in the context of standard viscous accretion disk theory. The principal result of this work is that X-ray novae that contain black hole primaries are about 100 times fainter that X-ray novae that contain neutron star primaries. This result had been suggested in earlier work, but the present work very firmly establishes this large luminosity difference. The result is remarkable because the black-hole and the neutron-star systems are believed to be similar in many respects. Most importantly, the mass transfer rate from the secondary star is believed to be very comparable for the two kinds of systems for similar orbital periods. The advection-dominated accretion flow (ADAF) model provides a natural framework for understanding the extraordinarily low luminosities of the black hole systems and the hundred-fold greater luminosities of the neutron star systems. The chief feature of an ADAF is that the heat energy in the accreting gas is trapped in the gas and travels with it, rather than being radiated promptly. Thus the accreting gas reaches the central object with a huge amount of thermal energy. If the accretor is a black hole, the

  5. Extending the search for neutrino point sources with IceCube above the horizon

    SciTech Connect

    IceCube Collaboration; Abbasi, R.

    2009-11-20

    Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This approach improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.

  6. Radiometric performance results of the New Horizons' ALICE UV imaging spectrograph

    NASA Astrophysics Data System (ADS)

    Slater, David C.; Davis, Michael W.; Olkin, Catherine B.; Scherrer, John; Stern, S. Alan

    2005-09-01

    We describe the radiometric performance and calibration results of the New Horizons' ALICE flight model. This ALICE is a lightweight (4.4 kg), low-power (4.4 W), ultraviolet spectrograph based on the ALICE instrument now in flight aboard the European Space Agency's Rosetta spacecraft. Its primary job will be to detect a variety of important atomic and molecular species in Pluto's atmosphere, and to determine their relative abundances so that a complete picture of Pluto's atmospheric composition can be determined for the first time. ALICE will also be used to search for an atmosphere around Pluto's moon, Charon, as well as the Kuiper Belt Objects (KBOs) New Horizons hopes to fly by after Pluto-Charon. Detailed radiometric performance results of the ALICE flight model are presented and discussed.

  7. Acceleration of a static observer near the event horizon of a static isolated black hole

    NASA Astrophysics Data System (ADS)

    Doughty, Noel A.

    1981-05-01

    The magnitude of the proper acceleration of a static observer (or test particle) in a static, isolated, spherically symmetric space-time region is compared with the Newtonian result including the situation in the interior of a perfect-fluid star. The calculation shows that the proper acceleration diverges on the event horizon of a spherically symmetric black hole. The 'surface gravity' of a spherically symmetric black hole, as used in descriptions of the Hawking radiation, is then explicitly related to the accelerations of such static observers, thus providing a simple physical interpretation of the surface gravity and illustrating the global (nonlocal) nature of the event horizon. The calculations are presented in the SI physical equations used almost exclusively by many students and teachers of physics.

  8. [Mapping stakeholders' preferences in prioritization criteria for horizon scanning in healthcare technologies].

    PubMed

    Nascimento, Aline do; Vidal, Avila Teixeira; Almeida, Rosimary Terezinha de

    2016-08-01

    Filtration and prioritization are two basics steps in horizon scanning systems. This article aimed to map stakeholders' preferences in the Brazilian Unified National Health System (SUS) regarding filtration and prioritization criteria. Two filtration criteria (time horizon and innovation) and eight prioritization criteria (relevance to epidemiology, health policies, and clinical practice; potential impact on SUS budget, healthcare providers' costs, and mortality; safety; and legal, ethical, and social aspects) were selected. Multiple correspondence analysis was used to map stakeholders' preferences within and between groups. Two groups were more homogeneous and determinant for selection of prioritization criteria. Stakeholders' professional experience had more influence than institutional affiliations. The approach showed transparent criteria selection and analysis of stakeholders' individual preferences. PMID:27487444

  9. Ion Characteristics in Jupiter's Magnetotail from New Horizon data

    NASA Astrophysics Data System (ADS)

    Hui, Debrup; Su, Yi-Jiun; Elliott, Heather; McComas, Dave; Bagenal, Fran; Crary, Frank

    2009-04-01

    Jupiter's gigantic magnetotail, extending 2500 Jovian radii, is the largest cohesive structure in our solar system. For the first time, NASA's New Horizons (NH) satellite in 2007 traversed almost axially. Data from its onboard SWAP instrument (Solar Wind Around Pluto), which makes coincidence measurements of the ions shows many periodic structures and existence of light and heavy ion species with varying densities in Jupiter's magnetotail plasma population. A better understanding of the physical processes governing such diversity requires knowing the characteristics of the various charged particles present, such as the ion density, velocity, temperature, and pressure. We have developed a 3-dimensional phase-space distribution model by constructing the observed signatures along with the calibration parameters provided by the SWAP team during the NH magnetotail flyby. The model uses five input parameters from SWAP. A 3-D isotropic Maxwellian distribution function is used to estimate density, velocity, and temperature, which is then converted into counts as the instrument measures the count rates. Finally, minimizing the chi-square fitting of our model results in the maximum likelihood of the various parameters. We will show our results from 500-800 RJ.

  10. Air quality implications of the Deepwater Horizon oil spill

    PubMed Central

    Middlebrook, Ann M.; Murphy, Daniel M.; Ahmadov, Ravan; Atlas, Elliot L.; Bahreini, Roya; Blake, Donald R.; Brioude, Jerome; de Gouw, Joost A.; Fehsenfeld, Fred C.; Frost, Gregory J.; Holloway, John S.; Lack, Daniel A.; Langridge, Justin M.; Lueb, Rich A.; McKeen, Stuart A.; Meagher, James F.; Meinardi, Simone; Neuman, J. Andrew; Nowak, John B.; Parrish, David D.; Peischl, Jeff; Perring, Anne E.; Pollack, Ilana B.; Roberts, James M.; Ryerson, Thomas B.; Schwarz, Joshua P.; Spackman, J. Ryan; Warneke, Carsten; Ravishankara, A. R.

    2012-01-01

    During the Deepwater Horizon (DWH) oil spill, a wide range of gas and aerosol species were measured from an aircraft around, downwind, and away from the DWH site. Additional hydrocarbon measurements were made from ships in the vicinity. Aerosol particles of respirable sizes were on occasions a significant air quality issue for populated areas along the Gulf Coast. Yields of organic aerosol particles and emission factors for other atmospheric pollutants were derived for the sources from the spill, recovery, and cleanup efforts. Evaporation and subsequent secondary chemistry produced organic particulate matter with a mass yield of 8 ± 4% of the oil mixture reaching the water surface. Approximately 4% by mass of oil burned on the surface was emitted as soot particles. These yields can be used to estimate the effects on air quality for similar events as well as for this spill at other times without these data. Whereas emission of soot from burning surface oil was large during the episodic burns, the mass flux of secondary organic aerosol to the atmosphere was substantially larger overall. We use a regional air quality model to show that some observed enhancements in organic aerosol concentration along the Gulf Coast were likely due to the DWH spill. In the presence of evaporating hydrocarbons from the oil, NOx emissions from the recovery and cleanup operations produced ozone. PMID:22205764

  11. Einstein Revisited - Gravity in Curved Spacetime Without Event Horizons

    NASA Astrophysics Data System (ADS)

    Leiter, Darryl

    2000-04-01

    In terms of covariant derivatives with respect to flat background spacetimes upon which the physical curved spacetime is imposed (1), covariant conservation of energy momentum requires, via the Bianchi Identity, that the Einstein tensor be equated to the matter energy momentum tensor. However the Einstein tensor covariantly splits (2) into two tensor parts: (a) a term proportional to the gravitational stress energy momentum tensor, and (b) an anti-symmetric tensor which obeys a covariant 4-divergence identity called the Freud Identity. Hence covariant conservation of energy momentum requires, via the Freud Identity, that the Freud tensor be equal to a constant times the matter energy momentum tensor. The resultant field equations (3) agree with the Einstein equations to first order, but differ in higher orders (4) such that black holes are replaced by "red holes" i.e., dense objects collapsed inside of their photon orbits with no event horizons. (1) Rosen, N., (1963), Ann. Phys. v22, 1; (2) Rund, H., (1991), Alg. Grps. & Geom. v8, 267; (3) Yilmaz, Hl, (1992), Nuo. Cim. v107B, 946; (4) Roberstson, S., (1999),Ap.J. v515, 365.

  12. Air quality implications of the Deepwater Horizon oil spill.

    PubMed

    Middlebrook, Ann M; Murphy, Daniel M; Ahmadov, Ravan; Atlas, Elliot L; Bahreini, Roya; Blake, Donald R; Brioude, Jerome; de Gouw, Joost A; Fehsenfeld, Fred C; Frost, Gregory J; Holloway, John S; Lack, Daniel A; Langridge, Justin M; Lueb, Rich A; McKeen, Stuart A; Meagher, James F; Meinardi, Simone; Neuman, J Andrew; Nowak, John B; Parrish, David D; Peischl, Jeff; Perring, Anne E; Pollack, Ilana B; Roberts, James M; Ryerson, Thomas B; Schwarz, Joshua P; Spackman, J Ryan; Warneke, Carsten; Ravishankara, A R

    2012-12-11

    During the Deepwater Horizon (DWH) oil spill, a wide range of gas and aerosol species were measured from an aircraft around, downwind, and away from the DWH site. Additional hydrocarbon measurements were made from ships in the vicinity. Aerosol particles of respirable sizes were on occasions a significant air quality issue for populated areas along the Gulf Coast. Yields of organic aerosol particles and emission factors for other atmospheric pollutants were derived for the sources from the spill, recovery, and cleanup efforts. Evaporation and subsequent secondary chemistry produced organic particulate matter with a mass yield of 8 ± 4% of the oil mixture reaching the water surface. Approximately 4% by mass of oil burned on the surface was emitted as soot particles. These yields can be used to estimate the effects on air quality for similar events as well as for this spill at other times without these data. Whereas emission of soot from burning surface oil was large during the episodic burns, the mass flux of secondary organic aerosol to the atmosphere was substantially larger overall. We use a regional air quality model to show that some observed enhancements in organic aerosol concentration along the Gulf Coast were likely due to the DWH spill. In the presence of evaporating hydrocarbons from the oil, NO(x) emissions from the recovery and cleanup operations produced ozone. PMID:22205764

  13. An Experiment to Detect Lunar Horizon Glow with the Lunar Orbit Laser Altimeter Laser Ranging Telescope

    NASA Astrophysics Data System (ADS)

    Smith, David E.; Zuber, Maria T.; Barker, Michael; Mazarico, Erwan; Neumann, Gregory A.; McClanahan, Timothy P.; Sun, Xiaoli

    2016-04-01

    Lunar horizon glow (LHG) was an observation by the Apollo astronauts of a brightening of the horizon around the time of sunrise. The effect has yet to be fully explained or confirmed by instruments on lunar orbiting spacecraft despite several attempts. The Lunar Reconnaissance Orbiter (LRO) spacecraft carries the laser altimeter (LOLA) instrument which has a 2.5 cm aperture telescope for Earth-based laser ranging (LR) mounted and bore-sighted with the high gain antenna (HGA). The LR telescope is connected to LOLA by a fiber-glass cable to one of its 5 detectors. For the LGH experiments the LR telescope is pointed toward the horizon shortly before lunar sunrise with the intent of observing any forward scattering of sunlight due to the presence of dust or particles in the field of view. Initially, the LR telescope is pointed at the dark lunar surface, which provides a measure of the dark count, and moves toward the lunar limb so as to measure the brightness of the sky just above the lunar limb immediately prior to lunar sunrise. At no time does the sun shine directly into the LR telescope, although the LR telescope is pointed as close to the sun as the 1.75-degree field of view permits. Experiments show that the LHG signal seen by the astronauts can be detected with a four-second integration of the noise counts.

  14. Fate and Speciation of Gasoline-Derived Lead in Organic Horizons of the Northeastern USA

    SciTech Connect

    Kaste,J.; Bostick, B.; Friedland, A.; Schroth, A.; Siccama, T.

    2006-01-01

    Although legislation in the late 1970s significantly reduced atmospheric lead (Pb) inputs to ecosystems in North America, organic (O) horizons in forests of the northeastern USA still contain up to 30 kg of gasoline-derived Pb ha{sup -1}. The residence time, geochemical behavior, and fate of this contaminant Pb in soils is poorly understood. Here we use forest floor time series data and synchrotron-based X-ray techniques to examine the mobility and speciation of Pb in O horizons collected from remote sites across the northeastern USA. At high elevation (>800 m) sites in Vermont and New York, samples collected from similar locations in 1980, 1990, and early 2000 had indistinguishable Pb contents, ranging ({+-}1{sigma}) from 11 to 29 kg Pb ha{sup -1}. However, at lower elevation and lower latitude sites with mixed vegetation, significant decreases in Pb amount were observed during the two-decade study period. Lower elevation sites ranged from 10 to 20 kg Pb ha{sup -1} in 1980, and from 2 to 10 kg Pb ha{sup -1} 20 yr later. Lead-enriched soil grains were determined to be amorphous with microfocused X-ray diffraction, and Pb concentrations correlated well with Fe on maps generated via microfocused X-ray fluorescence. Bulk Pb L{sub III}-edge X-ray absorption spectroscopy of coniferous O horizon samples indicate that Pb is binding to iron-rich soil particles by inner-sphere complexes, most likely to amorphous Fe oxides. Based on our paired regional and microscopic observations, we conclude that Pb is strongly retained in well-drained O horizons, and mobility is governed by decomposition and colloidal transport.

  15. Time?

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.

    2013-09-01

    The concept of time in the `clockwork' Newtonian world was irrelevant; and has generally been ignored until recently by several generations of physicists since the implementation of quantum mechanics. We will set aside the utility of time as a property relating to physical calculations of events relating to a metrics line element or as an aspect of the transformation of a particles motion/interaction in a coordinate system or in relation to thermodynamics etc., i.e. we will discard all the usual uses of time as a concept used to circularly define physical parameters in terms of other physical parameters; concentrating instead on time as an aspect of the fundamental cosmic topology of our virtual reality especially as it inseparably relates to the nature and role of the observer in natural science.

  16. Intrinsic geometry of a tidally deformed Kerr horizon

    NASA Astrophysics Data System (ADS)

    Poisson, Eric

    2013-04-01

    The intrinsic metric of a tidally deformed black-hole horizon can be presented in a coordinate system adapted to the horizon's null generators, with one coordinate acting as a running parameter along each generator, and two coordinates acting as constant generator labels. The metric is invariant under reparametrizations of the generators, and as such the horizon's intrinsic geometry is known to be gauge invariant. We consider a Kerr black hole deformed by a slowly-evolving external tidal field, and describe the intrinsic geometry of its event horizon in terms of the electric and magnetic tidal moments that characterize the tidal environment. When the black hole is slowly rotating, the horizon's geometry can be described in terms of a deviation from an otherwise spherical surface, and the deformation can be characterized by gauge invariant Love numbers. Some aspects of this tidal deformation have direct analogues in Newtonian physics. Some do not, and I will describe the similarities and differences between the tidal deformation of rotating black holes in general relativity and rotating fluid bodies in Newtonian physics.

  17. Quantization of Horizon Entropy and the Thermodynamics of Spacetime

    NASA Astrophysics Data System (ADS)

    Skákala, Jozef

    2014-06-01

    This is a review of my work published in the papers of Skakala (JHEP 1201:144, 2012; JHEP 1206:094, 2012) and Chirenti et al. (Phys. Rev. D 86:124008, 2012; Phys. Rev. D 87:044034, 2013). It offers a more detailed discussion of the results than the accounts in those papers, and it links my results to some conclusions recently reached by other authors. It also offers some new arguments supporting the conclusions in the cited articles. The fundamental idea of this work is that the semiclassical quantization of the black hole entropy, as suggested by Bekenstein (Phys. Rev. D 7:2333-2346, 1973), holds (at least) generically for the spacetime horizons. We support this conclusion by two separate arguments: (1) we generalize Bekenstein's lower bound on the horizon area transition to a much wider class of horizons than only the black-hole horizon, and (2) we obtain the same entropy spectra via the asymptotic quasi-normal frequencies of some particular spherically symmetric multi-horizon spacetimes (in the way proposed by Maggiore (Phys. Rev. Lett. 100:141301, 2008)). The main result of this paper supports the conclusions derived by Kothawalla et al. (Phys. Rev. D 78:104018, 2008) and Kwon and Nam (Class. Quant. Grav. 28:035007, 2011), on the basis of different arguments.

  18. Dynamical horizon entropy and equilibrium thermodynamics of generalized gravity theories

    SciTech Connect

    Wu Shaofeng; Ge Xianhui; Yang Guohong; Zhang Pengming

    2010-02-15

    We study the relation between the thermodynamics and field equations of generalized gravity theories on the dynamical trapping horizon with sphere symmetry. We assume the entropy of a dynamical horizon as the Noether charge associated with the Kodama vector and point out that it satisfies the second law when a Gibbs equation holds. We generalize two kinds of Gibbs equations to Gauss-Bonnet gravity on any trapping horizon. Based on the quasilocal gravitational energy found recently for f(R) gravity and scalar-tensor gravity in some special cases, we also build up the Gibbs equations, where the nonequilibrium entropy production, which is usually invoked to balance the energy conservation, is just absorbed into the modified Wald entropy in the Friedmann-Robertson-Walker spacetime with slowly varying horizon. Moreover, the equilibrium thermodynamic identity remains valid for f(R) gravity in a static spacetime. Our work provides an alternative treatment to reinterpret the nonequilibrium correction and supports the idea that the horizon thermodynamics is universal for generalized gravity theories.

  19. Radio Occultation Measurements of Pluto’s Atmosphere with New Horizons

    NASA Astrophysics Data System (ADS)

    Hinson, David P.; Linscott, Ivan; Tyler, Len; Bird, Mike; Paetzold, Martin; Strobel, Darrell; Summers, Mike; Woods, Will; Stern, Alan; Weaver, Hal; Olkin, Cathy; Young, Leslie; Ennico, Kimberly; Gladstone, Randy; Greathouse, Tommy; Kammer, Josh; Parker, Alex; Parker, Joel; Retherford, Kurt; Schindhelm, Eric; Singer, Kelsi; Steffl, Andrew; Tsang, Con; Versteeg, Maarten

    2015-11-01

    The reconnaissance of the Pluto System by New Horizons included radio occultations at both Pluto and Charon. This talk will present the latest results from the Pluto occultation. The REX instrument onboard New Horizons received and recorded uplink signals from two 70-m antennas and two 34-m antennas of the NASA Deep Space Network - each transmitting 20 kW at 4.2-cm wavelength - during a diametric occultation by Pluto. At the time this was written only a short segment of data at occultation entry (193°E, 17°S) was available for analysis. The REX measurements extend unequivocally to the surface, providing the first direct measure of the surface pressure and the temperature structure in Pluto’s lower atmosphere. Data from occultation exit (16°E, 15°N) are scheduled to arrive on the ground in late August 2015. Those observations will yield an improved estimate of the surface pressure, a second temperature profile, and a measure of the diameter of Pluto with a precision of a few hundred meters. This work is supported by the NASA New Horizons Mission.

  20. Interacting entropy-corrected holographic dark energy with apparent horizon as an infrared cutoff

    NASA Astrophysics Data System (ADS)

    Khodam-Mohammadi, A.; Malekjani, M.

    2012-05-01

    In this work we consider the entropy-corrected version of interacting holographic dark energy (HDE), in the non-flat universe enclosed by apparent horizon. Two corrections of entropy so-called logarithmic `LEC' and power-law `PLEC' in HDE model with apparent horizon as an IR-cutoff are studied. The ratio of dark matter to dark energy densities u, equation of state parameter w D and deceleration parameter q are obtained. We show that the cosmic coincidence problem is solved for interacting models. By studying the effect of interaction in EoS parameter of both models, we see that the phantom divide may be crossed and also understand that the interacting models can drive an acceleration expansion at the present and future, while in non-interacting case, this expansion can happen only at the early time. The graphs of deceleration parameter for interacting models, show that the present acceleration expansion is preceded by a sufficiently long period deceleration at past. Moreover, the thermodynamical interpretation of interaction between LECHDE and dark matter is described. We obtain a relation between the interaction term of dark components and thermal fluctuation in a non-flat universe, bounded by the apparent horizon. In limiting case, for ordinary HDE, the relation of interaction term versus thermal fluctuation is also calculated.

  1. Atmospheric transport of neutrons and gamma rays from near-horizon nuclear detonations

    SciTech Connect

    Byrd, R.C.; Heerema, B.D.

    1996-03-01

    This report continues a study of the transport of neutrons and rays from nuclear detonations at high altitudes to a set of detectors, with an emphasis on the limiting case of sources even beyond the horizon. To improve the calculational efficiency, the standard arrangement of a single source with multiple detectors is transformed to an equivalent one with a single detector and sources at multiple locations. Particular attention is paid to the critical problem of transport at near-horizon angles in an atmosphere whose density decreases exponentially with altitude. As a check, calculations for this region are made using both analytical and Monte Carlo approaches. For sources approaching the horizon, the fluence of gamma rays and neutrons reaching the detector drops gradually as the increasing column density attenuates the direct, unscattered fluence. Near the grazing angle, the direct fluence plummets, but the scattered component continues to decrease slowly and remains observable. Over this range, the timedependent flux of direct-plus-scattered gamma rays changes dramatically in both shape and magnitude, but it probably remains distinct from typical natural backgrounds. The neutron time-of-flight spectrum is dominated by scattering and reflects only the most important aspects of the original source spectrum; its most obvious features are a prominent low-energy tail and the resonance structure produced by nuclear interactions in the atmosphere. In some cases, the fluence of secondary gamma rays produced by these interactions may be larger than that from the source itself.

  2. The late Barremian Halimedides horizon of the Dolomites (Southern Alps, Italy)

    PubMed Central

    Lukeneder, Alexander; Uchman, Alfred; Gaillard, Christian; Olivero, Davide

    2012-01-01

    A new trace fossil marker level, the Halimedides horizon, is proposed for the Lower Cretaceous pelagic to hemipelagic succession of the Puez area (Southern Alps, Italy). The horizon occurs in the middle part of the late Barremian Gerhardtia sartousiana Zone (Gerhardtia sartousiana Subzone). It is approximately 20 cm thick and restricted to the uppermost part of the Puez Limestone Member (marly limestones; Hauterivian–Barremian; Puez Formation). It is fixed to the top 20 cm of bed P1/204. The grey–whitish limestone bed of the G. sartousiana Zone is penetrated by Aptian red marls–siltstones of the Redbed Member. The horizon is documented for the first time from the Southern Alps, including the Dolomites, and can be correlated with other Mediterranean localities. The trace fossil assemblage of this marker bed with the co-occurrence of Halimedides, Spongeliomorpha and Zoophycos sheds light on the Lower Cretaceous sedimentological history and current system of the Puez area within the Dolomites. It also highlights the palaeoenvironmental evolution of basins and plateaus and provides insights into the late Barremian interval. PMID:27087717

  3. Stationary holographic plasma quenches and numerical methods for non-killing horizons.

    PubMed

    Figueras, Pau; Wiseman, Toby

    2013-04-26

    We explore use of the harmonic Einstein equations to numerically find stationary black holes where the problem is posed on an ingoing slice that extends into the interior of the black hole. Requiring no boundary conditions at the horizon beyond smoothness of the metric, this method may be applied for horizons that are not Killing. As a nontrivial illustration we find black holes which, via AdS-CFT, describe a time-independent CFT plasma flowing through a static spacetime which asymptotes to Minkowski in the flow's past and future, with a varying spatial geometry in between. These are the first nonperturbative examples of stationary black holes which do not have Killing horizons. When the CFT spacetime slowly varies, the CFT stress tensor derived from gravity is well described by viscous hydrodynamics. For fast variation it is not, and the solutions are stationary analogs of dynamical quenches, with the plasma being suddenly driven out of equilibrium. We find evidence these flows become unstable for sufficiently strong quenches, and speculate the instability may be turbulent. PMID:23679705

  4. Multiple microtektite horizons in upper eocene marine sediments: no evidence for mass extinctions.

    PubMed

    Keller, G; D'Hondt, S; Vallier, T L

    1983-07-01

    Microtektites have been recovered from three horizons in eight middle Eocene to middle Oligocene marine sediment sequences. Five of these occurrences are coeval and of latest Eocene age (37.5 to 38.0 million years ago); three are coeval and of early late Eocene age (38.5 to 39.5 million years ago); and three are of middle Oligocene age (31 to 32 million years ago). In addition, rare probable microtektites have been found in sediments with ages of about 36.0 to 36.5 million years. The microtektite horizon at 37.5 to 38.0 million years can be correlated with the North American tektite-strewn field, which has a fission track age (minimum) of 34 to 35 million years and a paleomagnetic age of 37.5 to 38.0 million years. There is no evidence for mass faunal extinctions at any of the microtektite horizons. Many of the distinct faunal changes that occurred in the middle Eocene to middle Oligocene can be related to the formation of the Antarctic ice sheet and the associated cooling phenomena and intensification of bottom currents that led to large-scale dissolution of calcium carbonate and erosion, which created areally extensive hiatuses in the deep-sea sediment records. The occurrence of microtektite horizons of several ages and the lack of evidence for faunal extinctions suggest that the effects of extraterrestrial bolide impacts may be unimportant in the biologic realm during middle Eocene to middle Oligocene time. PMID:17769212

  5. A disconnect between O horizon and mineral soil carbon - Implications for soil C sequestration

    SciTech Connect

    Garten Jr, Charles T

    2009-01-01

    Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO{sub 2} concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental litter additions (three times ambient) in an upland and a valley that differed in soil nitrogen availability. The estimated decomposition rate of the carbon stock in the O horizon was greater in the valley than in the upland due to higher litter quality (i.e., lower C/N ratios). Short-term litter exclusion or addition had no effect on carbon stock in the mineral soil, measured to a depth of 30 cm, or the partitioning of carbon in the mineral soil between particulate- and mineral-associated organic matter. A two-compartment model was used to interpret results from the field experiments. Field data and a sensitivity analysis of the model were consistent with little carbon transfer between the O horizon and the mineral soil. Increasing aboveground carbon input does not appear to be an effective means of promoting carbon sequestration in forest soil at the location of the present study because a disconnect exists in carbon dynamics between O horizon and mineral soil. Factors that directly increase inputs to belowground soil carbon, via roots, or reduce decomposition rates of organic matter are more likely to benefit efforts to increase carbon sequestration in forests where carbon dynamics in the O horizon are uncoupled from the mineral soil.

  6. A disconnect between O horizon and mineral soil carbon - Implications for soil C sequestration

    NASA Astrophysics Data System (ADS)

    Garten, Charles T., Jr.

    2009-03-01

    Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO 2 concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental litter additions (three times ambient) in an upland and a valley that differed in soil nitrogen availability. The estimated decomposition rate of the carbon stock in the O horizon was greater in the valley than in the upland due to higher litter quality (i.e., lower C/N ratios). Short-term litter exclusion or addition had no effect on carbon stock in the mineral soil, measured to a depth of 30 cm, or the partitioning of carbon in the mineral soil between particulate- and mineral-associated organic matter. A two-compartment model was used to interpret results from the field experiments. Field data and a sensitivity analysis of the model were consistent with little carbon transfer between the O horizon and the mineral soil. Increasing aboveground carbon input does not appear to be an effective means of promoting carbon sequestration in forest soil at the location of the present study because a disconnect exists in carbon dynamics between O horizon and mineral soil. Factors that directly increase inputs to belowground soil carbon, via roots, or reduce decomposition rates of organic matter are more likely to benefit efforts to increase carbon sequestration in forests where carbon dynamics in the O horizon are uncoupled from the mineral soil.

  7. Asymptotically Lifshitz spacetimes with universal horizons in (1 +2 ) dimensions

    NASA Astrophysics Data System (ADS)

    Basu, Sayandeb; Bhattacharyya, Jishnu; Mattingly, David; Roberson, Matthew

    2016-03-01

    Hořava gravity theory possesses global Lifshitz space as a solution and has been conjectured to provide a natural framework for Lifshitz holography. We derive the conditions on the two-derivative Hořava gravity Lagrangian that are necessary for static, asymptotically Lifshitz spacetimes with flat transverse dimensions to contain a universal horizon, which plays a similar thermodynamic role as the Killing horizon in general relativity. Specializing to z =2 in 1 +2 dimensions, we then numerically construct such regular solutions over the whole spacetime. We calculate the mass for these solutions and show that, unlike the asymptotically anti-de Sitter case, the first law applied to the universal horizon is straightforwardly compatible with a thermodynamic interpretation.

  8. Thermodynamics of event horizons in (2+1)-dimensional gravity

    SciTech Connect

    Reznik, B. )

    1992-03-15

    Although gravity in 2+1 dimensions is very different in nature from gravity in 3+1 dimensions, it is shown that the laws of thermodynamics for event horizons can be manifested also for (2+1)-dimensional gravity. The validity of the classical laws of horizon mechanics is verified in general and exemplified for the (2+1)-dimensional analogues of Reissner-Nordstroem and Schwarzschild--de Sitter spacetimes. We find that the entropy is given by 1/4{ital L}, where {ital L} is the length of the horizon. A consequence of having consistent thermodynamics is that the second law fixes the sign of Newton's constant to be positive.

  9. Black hole thermodynamics from near-horizon conformal quantum mechanics

    SciTech Connect

    Camblong, Horacio E.; Ordonez, Carlos R.

    2005-05-15

    The thermodynamics of black holes is shown to be directly induced by their near-horizon conformal invariance. This behavior is exhibited using a scalar field as a probe of the black hole gravitational background, for a general class of metrics in D spacetime dimensions (with D{>=}4). The ensuing analysis is based on conformal quantum mechanics, within a hierarchical near-horizon expansion. In particular, the leading conformal behavior provides the correct quantum statistical properties for the Bekenstein-Hawking entropy, with the near-horizon physics governing the thermodynamics from the outset. Most importantly: (i) this treatment reveals the emergence of holographic properties; (ii) the conformal coupling parameter is shown to be related to the Hawking temperature; and (iii) Schwarzschild-like coordinates, despite their 'coordinate singularity', can be used self-consistently to describe the thermodynamics of black holes.

  10. Deepwater Horizon oil spill monitoring using airborne multispectral infrared imagery

    NASA Astrophysics Data System (ADS)

    Shen, Sylvia S.; Lewis, Paul E.

    2011-06-01

    On April 28, 2010, the Environmental Protection Agency's (EPA) Airborne Spectral Photometric Environmental Collection Technology (ASPECT) aircraft was deployed to Gulfport, Mississippi to provide airborne remotely sensed air monitoring and situational awareness data and products in response to the Deepwater Horizon oil spill disaster. The ASPECT aircraft was released from service on August 9, 2010 after having flown over 85 missions that included over 325 hours of flight operation. This paper describes several advanced analysis capabilities specifically developed for the Deepwater Horizon mission to correctly locate, identify, characterize, and quantify surface oil using ASPECT's multispectral infrared data. The data products produced using these advanced analysis capabilities provided the Deepwater Horizon Incident Command with a capability that significantly increased the effectiveness of skimmer vessel oil recovery efforts directed by the U.S. Coast Guard, and were considered by the Incident Command as key situational awareness information.

  11. FOAM: Expanding the horizons of climate modeling

    SciTech Connect

    Tobis, M.; Foster, I.T.; Schafer, C.M.

    1997-10-01

    We report here on a project that expands the applicability of dynamic climate modeling to very long time scales. The Fast Ocean Atmosphere Model (FOAM) is a coupled ocean atmosphere model that incorporates physics of interest in understanding decade to century time scale variability. It addresses the high computational cost of this endeavor with a combination of improved ocean model formulation, low atmosphere resolution, and efficient coupling. It also uses message passing parallel processing techniques, allowing for the use of cost effective distributed memory platforms. The resulting model runs over 6000 times faster than real time with good fidelity, and has yielded significant results.

  12. Electrodynamics with a Future Conformal Horizon

    SciTech Connect

    Ibison, Michael

    2010-12-22

    We investigate the impact of singularities occurring at future times in the Friedmann equations expressed in conformal coordinates to determine the consequences of extending the time coordinate through the singularity for the physics of matter and radiation occupying just one side. Mostly this involves investigation of the relationship between the metric with line element ds{sup 2} a{sup 2}(t)(dt{sup 2}-dx{sup 2}) and time reversal symmetry within electrodynamics. It turns out compatibility between these two is possible only if there is a singular physical event at the time of the singularity or if the topology is not trivial. In both cases the singularity takes on the appearance of a time-like mirror. We are able to demonstrate a relationship between the broken time symmetry in electrodynamics characterized by retarded radiation and radiation reaction and the absolute conformal time relative to the time of the singularity, i.e. between the Electromagnetic and Cosmological arrows of time. It is determined that the Wheeler-Feynman reasoning but with the future absorber replaced by the Cosmological mirror leads to a conflict with observation unless matter is strongly bound electromagnetically to the environment.

  13. A Horizon Scan of Global Conservation Issues for 2016.

    PubMed

    Sutherland, William J; Broad, Steven; Caine, Jacqueline; Clout, Mick; Dicks, Lynn V; Doran, Helen; Entwistle, Abigail C; Fleishman, Erica; Gibbons, David W; Keim, Brandon; LeAnstey, Becky; Lickorish, Fiona A; Markillie, Paul; Monk, Kathryn A; Mortimer, Diana; Ockendon, Nancy; Pearce-Higgins, James W; Peck, Lloyd S; Pretty, Jules; Rockström, Johan; Spalding, Mark D; Tonneijck, Femke H; Wintle, Bonnie C; Wright, Katherine E

    2016-01-01

    This paper presents the results of our seventh annual horizon scan, in which we aimed to identify issues that could have substantial effects on global biological diversity in the future, but are not currently widely well known or understood within the conservation community. Fifteen issues were identified by a team that included researchers, practitioners, professional horizon scanners, and journalists. The topics include use of managed bees as transporters of biological control agents, artificial superintelligence, electric pulse trawling, testosterone in the aquatic environment, building artificial oceanic islands, and the incorporation of ecological civilization principles into government policies in China. PMID:26688445

  14. Near-horizon solution for Dvali-Gabadadze-Porrati perturbations

    SciTech Connect

    Sawicki, Ignacy; Song, Yong-Seon; Hu, Wayne

    2007-03-15

    We develop a scaling ansatz for the master equation in Dvali, Gabadadze, Porrati cosmologies, which allows us to solve the equations of motion for perturbations off the brane during periods when the on-brane evolution is scale free. This allows us to understand the behavior of the gravitational potentials outside the horizon at high redshifts and close to the horizon today. We confirm that the results of Koyama and Maartens are valid at scales relevant for observations such as galaxy-ISW correlations. At larger scales, there is an additional suppression of the potential which reduces the growth rate even further and would strengthen the integrated Sachs-Wolf effect.

  15. Earth, Meet Pluto: The New Horizons Education and Communications Partnership

    NASA Astrophysics Data System (ADS)

    Buckley, M.

    2015-12-01

    The unique partnership between the NASA New Horizons education/communications and public affairs programs tapped into the excitement of visiting an unexplored planet in a new region of the solar system - resulting in unprecedented public participation in and coverage of a planetary mission. With a range of hands-on learning experiences, Web materials and online , the program provided opportunities for students, educators, museums, science centers, the media, Web surfers and other members of the public to ride along on the first mission to Pluto and the Kuiper Belt. The programs leveraged resources, materials and expertise to address a wide range of traditional and nontraditional audiences while providing consistent messages and information on this historic NASA endeavor. The E/C program included a variety of formal lesson plans and learning materials — based on New Horizons science and engineering goals, and aligned with National Research Council's National Science Education Standards — that continue to help students in grades K-12 learn more about science, technology, engineering and mathematics. College students designed and built an actual flight instrument on New Horizons and held internships with the spacecraft integration and test team. New Horizons E/C programs went well beyond the classroom, from a chance for people to send their names to Pluto on board the New Horizons spacecraft before launch, to opportunities for the public to access milestone events and the first-ever close-up views of Pluto in places such as museums, science centers and libraries, TV and the Web — as well as thousands who attended interactive "Plutopalooza" road shows across the country. Teamed with E/C was the public affairs strategy to communicate New Horizons news and messages to media, mission stakeholders, the scientific community and the public. These messages include various aspects of New Horizons, including the progress of the mission and key milestones and achievements

  16. A horizon scan of global conservation issues for 2014.

    PubMed

    Sutherland, William J; Aveling, Rosalind; Brooks, Thomas M; Clout, Mick; Dicks, Lynn V; Fellman, Liz; Fleishman, Erica; Gibbons, David W; Keim, Brandon; Lickorish, Fiona; Monk, Kathryn A; Mortimer, Diana; Peck, Lloyd S; Pretty, Jules; Rockström, Johan; Rodríguez, Jon Paul; Smith, Rebecca K; Spalding, Mark D; Tonneijck, Femke H; Watkinson, Andrew R

    2014-01-01

    This paper presents the output of our fifth annual horizon-scanning exercise, which aims to identify topics that increasingly may affect conservation of biological diversity, but have yet to be widely considered. A team of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics which were identified via an iterative, Delphi-like process. The 15 topics include a carbon market induced financial crash, rapid geographic expansion of macroalgal cultivation, genetic control of invasive species, probiotic therapy for amphibians, and an emerging snake fungal disease. PMID:24332318

  17. A horizon scan of global conservation issues for 2014

    PubMed Central

    Sutherland, William J.; Aveling, Rosalind; Brooks, Thomas M.; Clout, Mick; Dicks, Lynn V.; Fellman, Liz; Fleishman, Erica; Gibbons, David W.; Keim, Brandon; Lickorish, Fiona; Monk, Kathryn A.; Mortimer, Diana; Peck, Lloyd S.; Pretty, Jules; Rockström, Johan; Rodríguez, Jon Paul; Smith, Rebecca K.; Spalding, Mark D.; Tonneijck, Femke H.; Watkinson, Andrew R.

    2014-01-01

    This paper presents the output of our fifth annual horizon-scanning exercise, which aims to identify topics that increasingly may affect conservation of biological diversity, but have yet to be widely considered. A team of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics which were identified via an iterative, Delphi-like process. The 15 topics include a carbon market induced financial crash, rapid geographic expansion of macroalgal cultivation, genetic control of invasive species, probiotic therapy for amphibians, and an emerging snake fungal disease. PMID:24332318

  18. Robust Consumption-Investment Problem on Infinite Horizon

    SciTech Connect

    Zawisza, Dariusz

    2015-12-15

    In our paper we consider an infinite horizon consumption-investment problem under a model misspecification in a general stochastic factor model. We formulate the problem as a stochastic game and finally characterize the saddle point and the value function of that game using an ODE of semilinear type, for which we provide a proof of an existence and uniqueness theorem for its solution. Such equation is interested on its own right, since it generalizes many other equations arising in various infinite horizon optimization problems.

  19. The New Horizons Mission to Pluto and Flyby of Jupiter

    NASA Technical Reports Server (NTRS)

    Stern, Alan; Weaver, Hal; Young, Leslie; Bagenal, Fran; Binzel, Richard; Buratti, Bonnie; Cheng, andy; Cruikshank, Dale; Gladstone, Randy; Grundy, Will; Hinson, David; Horanyi, Mihaly; Jennings, Don; Linscott, Ivan; McComas, Dave; McKinnon, William; McNutt, Ralph; Moore, Jeffrey; Murchie, Scott; Olkin, Cathy; Porco, Carolyn; Reitsema, Harold; Reuter, Dennis; Slater, Dave; Spencer, John

    2008-01-01

    New Horizons (NH) is NASA's mission to provide the first in situ reconnaissance of Pluto and its moons Charon, Nix, and Hydra. The NH spacecraft will reach Pluto in July 2015 and will then, if approved for an extended mission phase, continue on to a flyby encounter with one or more Kuiper belt objects (KBOs). NH was launched on 19 January 2006 and received a gravity assist during a flyby encounter with Jupiter (with closest approach at -32 RJ on 28 February 2007) that reduced its flight time to Pluto by 3 years. During the Jupiter flyby, NH collected a trove of multi-wavelength imaging and fields-and-particles measurements. Among the many science results at Jupiter were a detection of planet-wide mesoscale waves, eruptions of atmospheric ammonia clouds, unprecedented views of Io's volcanic plumes and Jupiter's tenuous ring system, a first close-up of the Little Red Spot (LRS), first sightings of polar lightning, and a trip down the tail of the magnetosphere. In 2015, NH will conduct a seven-month investigation of the Pluto system culminating in a closest approach some 12,500 km from Pluto's surface. Planning is presently underway for the Pluto encounter with special emphasis on longidentified science goals of studying the terrain, geology, and composition of the surfaces of Pluto and Charon, examining the composition and structure of Pluto's atmosphere, searching for an atmosphere on Charon, and characterizing Pluto's ionosphere and solar wind interaction. Detailed inspections will also be performed of the newly discovered satellites Nix and Hydra. Additionally, NH will characterize energetic particles in Pluto's environment, refine the bulk properties of Pluto and Charon, and search for additional satellites and rings.

  20. A Review of Seafood Safety after the Deepwater Horizon Blowout

    PubMed Central

    Doke, Dzigbodi; Tipre, Meghan; Leader, Mark; Fitzgerald, Timothy

    2011-01-01

    Background: The Deepwater Horizon (DH) blowout resulted in fisheries closings across the Gulf of Mexico. Federal agencies, in collaboration with impacted Gulf states, developed a protocol to determine when it is safe to reopen fisheries based on sensory and chemical analyses of seafood. All federal waters have been reopened, yet concerns have been raised regarding the robustness of the protocol to identify all potential harmful exposures and protect the most sensitive populations. Objectives: We aimed to assess this protocol based on comparisons with previous oil spills, published testing results, and current knowledge regarding chemicals released during the DH oil spill. Methods: We performed a comprehensive review of relevant scientific journal articles and government documents concerning seafood contamination and oil spills and consulted with academic and government experts. Results: Protocols to evaluate seafood safety before reopening fisheries have relied on risk assessment of health impacts from polycyclic aromatic hydrocarbon (PAH) exposures, but metal contamination may also be a concern. Assumptions used to determine levels of concern (LOCs) after oil spills have not been consistent across risk assessments performed after oil spills. Chemical testing results after the DH oil spill suggest PAH levels are at or below levels reported after previous oil spills, and well below LOCs, even when more conservative parameters are used to estimate risk. Conclusions: We recommend use of a range of plausible risk parameters to set bounds around LOCs, comparisons of post-spill measurements with baseline levels, and the development and implementation of long-term monitoring strategies for metals as well as PAHs and dispersant components. In addition, the methods, results, and uncertainties associated with estimating seafood safety after oil spills should be communicated in a transparent and timely manner, and stakeholders should be actively involved in developing a long