Emission spectra of self-dual black holes

We calculate the particle spectra of evaporating self-dual black holes that are potential dark matter candidates. We first estimate the relevant mass and temperature range and find that the masses are below the Planck mass, and the temperature of the black holes is small compared to their mass. In this limit, we then derive the number-density of the primary emission particles, and, by studying the wave-equation of a scalar field in the background metric of the black hole, show that we can use the low energy approximation for the greybody factors. We finally arrive at the expression for the spectrum of secondary particle emission from a dark matter halo constituted of self-dual black holes.Comment: 15 pages, 6 figures, typos corrected, reference adde

Intraday trading in the overnight federal funds market

Transaction-level data for the federal funds market provide a rare look at the intraday behavior of trade volume and prices. An analysis of the data reveals that trade volume exhibits large swings over the course of the day while prices remain fairly stable, with rate volatility rising sharply only in the late afternoon. The analysis underscores the important role played by institutional deadlines-most notably, the close of trading-in driving movements in this market.Federal funds market (United States)

In, Through and Beyond the Planck Scale

In this paper we have recalled the semiclassical metric obtained from a classical analysis of the loop quantum black hole (LQBH). We show that the regular Reissner-Nordstr\"om-like metric is self-dual in the sense of T-duality: the form of the metric is invariant under the exchange r -> a0/r where a0 is proportional to the minimum area in LQG. Of particular interest, the symmetry imposes that if an observer at infinity sees a black hole of mass m an observer in the other asymptotic infinity beyond the horizon (near r=0) sees a dual mass proportional to m_P^2/m. We then show that small LQBHs are stable and could be a component of dark matter. Ultra-light LQBHs created shortly after the Big Bang would now have a mass of approximately 10^(-5) m_P and emit radiation with a typical energy of about 10^(13) - 10^(14) eV but they would also emit cosmic rays of much higher energies, albeit few of them. If these small LQBHs form a majority of the dark matter of the Milky Way's Halo, the production rate of ultra-high-energy-cosmic-rays (UHECR) by these ultra light black holes would be compatible with the observed rate of the Auger detector.Comment: 10 pages, 8 figures; to appear in the Proceedings of the XXV Max Born Symposium "The Planck Scale", Wroclaw, 29 June - 3 July, 200

Generalized Uncertainty Principle and Self-dual Black Holes

The Generalized Uncertainty Principle suggests corrections to the Uncertainty Principle as the energy increases towards the Planck value. It provides a natural transition between the expressions for the Compton wavelength below the Planck mass and the black hole event horizon size above this mass. It also suggests corrections to the the event horizon size as the black hole mass falls towards the Planck value, leading to the concept of a Generalized Event Horizon. Extrapolating below the Planck mass suggests the existence of a new class of black holes, whose size is of order the Compton wavelength for their mass. Such sub-Planckian black holes have recently been discovered in the context of loop quantum gravity and it is possible that this applies more generally. This suggests an intriguing connection between black holes, the Uncertainty Principle and quantum gravity.Comment: 13 Pages, 6 figure

Fotoperíodo e temperatura na germinação de sementes de maracujá 'SCS437 Catarina'

The passion fruit (Passiflora edulis Sims.) propagates by sexual reproduction and presents slow and uneven seed germination. This work has the goal of identifying a temperature and photoperiod that provide greater germination of the cultivar SCS 437 Catarina. We used an entirely randomized experimental design in a 2 x 3 + 1 factorial: two temperatures (alternating between 20/30 ºC and constant 25 ºC) and three photoperiods (8/16 – 8 hours of light and 16 hours of darkness; 12/12 – 12 hours of light and 12 hours of darkness; and absence of light), and for alternating temperature, an absence of light treatment was added, being classified as neutral photoblastic, and at a constant temperature of 25 ºC made germination unfeasible, while the 20/30 ºC alternating temperatures provided an average germination of 75%. The seeds showed an indifferent behavior to light, and the temperature alternated with 12/12 h photoperiod was the ideal condition to promote a higher percentage of germination.O maracujazeiro-azedo (Passiflora edulis Sims.) é propagado por via sexuada e apresenta germinação lenta e desuniforme das sementes. O objetivo do trabalho foi identificar a temperatura e o fotoperíodo que proporcionam maior germinação da cultivar SCS 437 Catarina. Foi utilizado o delineamento inteiramente casualizado em esquema fatorial 2 x 3 + 1: duas temperaturas (alternada de 20/30 ºC e constante de 25 ºC) e três fotoperíodos (8/16 - 8 horas de luz e 16 horas de escuro; 12/12 - 12 horas de luz e 12 horas de escuro; e ausência de luz), e para temperatura alternada foi adicionado um tratamento de ausência de luz, sendo classificadas como fotoblásticas neutras, e a temperatura constante de 25 ºC inviabilizou a germinação, enquanto a temperatura alternada 20/30 ºC proporcionou germinação de 75 %. As sementes apresentaram um comportamento indiferente à luz, e a temperatura alternada com fotoperíodo 12/12 h foi a condição ideal para promover maior percentual de germinação

N=8 gaugings revisited: an exhaustive classification

In this paper we reconsider, for N=8 supergravity, the problem of gauging the most general electric subgroup. We show that admissible theories are fully characterized by a single algebraic equation to be satisfied by the embedding of the gauge group G within the electric subalgebra SL(8,\IR) of E_{7(7)}. The complete set of solutions to this equation contains 36 parameters. Modding by the action of SL(8,\IR) conjugations that yield equivalent theories all continuous parameters are eliminated except for an overall coupling constant and we obtain a discrete set of orbits. This set is in one--to--one correspondence with 36 Lie subalgebras of SL(8,\IR), corresponding to all possible real forms of the SO(8) Lie algebra plus a set of contractions thereof. By means of our analysis we establish the theorem that the N=8 gaugings constructed by Hull in the middle eighties constitute the exhaustive set of models. As a corollary we show that there exists a unique 7--dimensional abelian gauging. The corresponding abelian algebra is not contained in the maximal abelian ideal of the solvable Lie algebra generating the scalar manifold E_{7(7)}/SU(8).Comment: 1 LaTeX file, 41 pages, 3 eps-figure

Tachyonic open inflationary universes

We study one-field open inflationary models in a universe dominated by tachyon matter. In these scenarios, we determine and characterize the existence of the Coleman-De Lucia (CDL) instanton. Also, we study the Lorentzian regime, that is, the period of inflation after tunnelling has occurred.Comment: 13 pages, 7 figures. Accepted by Physics Letters