Heartbeat of the Southern Oscillation explains ENSO climatic resonances

The El Ni~no-Southern Oscillation (ENSO) nonlinear oscillator phenomenon has a far reaching influence on the climate and human activities. The up to 10 year quasi-period cycle of the El Ni~no and subsequent La Ni~na is known to be dominated in the tropics by nonlinear physical interaction of wind with the equatorial waveguide in the Pacific. Long-term cyclic phenomena do not feature in the current theory of the ENSO process. We update the theory by assessing low (>10 years) and high (<10 years) frequency coupling using evidence across tropical, extratropical, and Pacific basin scales. We analyze observations and model simulations with a highly accurate method called Dominant Frequency State Analysis (DFSA) to provide evidence of stable ENSO features. The observational data sets of the Southern Oscillation Index (SOI), North Pacific Index Anomaly, and ENSO Sea Surface Temperature Anomaly, as well as a theoretical model all confirm the existence of long-term and short-term climatic cycles of the ENSO process with resonance frequencies of {2.5, 3.8, 5, 12–14, 61–75, 180} years. This fundamental result shows long-term and short-term signal coupling with mode locking across the dominant ENSO dynamics. These dominant oscillation frequency dynamics, defined as ENSO frequency states, contain a stable attractor with three frequencies in resonance allowing us to coin the term Heartbeat of the Southern Oscillation due to its characteristic shape. We predict future ENSO states based on a stable hysteresis scenario of short-term and long-term ENSO oscillations over the next century

Factorization and Lie point symmetries of general Lienard-type equation in the complex plane

We present a variational approach to a general Lienard-type equation in order to linearize it and, as an example, the Van der Pol oscillator is discussed. The new equation which is almost linear is factorized. The point symmetries of the deformed equation are also discussed and the two-dimensional Lie algebraic generators are obtained

Generation of coherent terahertz pulses in Ruby at room temperature

We have shown that a coherently driven solid state medium can potentially produce strong controllable short pulses of THz radiation. The high efficiency of the technique is based on excitation of maximal THz coherence by applying resonant optical pulses to the medium. The excited coherence in the medium is connected to macroscopic polarization coupled to THz radiation. We have performed detailed simulations by solving the coupled density matrix and Maxwell equations. By using a simple $V$-type energy scheme for ruby, we have demonstrated that the energy of generated THz pulses ranges from hundreds of pico-Joules to nano-Joules at room temperature and micro-Joules at liquid helium temperature, with pulse durations from picoseconds to tens of nanoseconds. We have also suggested a coherent ruby source that lases on two optical wavelengths and simultaneously generates THz radiation. We discussed also possibilities of extension of the technique to different solid-state materials

Measurements of production and inelastic cross sections for p+C, p+Be, and p+Al at 60 GeV/c and p+C and p+Be at 120 GeV/c

This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV=c protons with C, Be, Al targets and 120 GeV=c protons with C and Be targets. The analysis is performed using the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. First measurements are obtained using protons at 120 GeV=c, while the results for protons at 60 GeV=c are compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.Authors:A. Aduszkiewicz,15 E. V. Andronov,21 T. Antićić,3 V. Babkin,19 M. Baszczyk,13 S. Bhosale,10 A. Blondel,23 M. Bogomilov,2 A. Brandin,20 A. Bravar,23 W. Bryliński,17 J. Brzychczyk,12 M. Buryakov,19 O. Busygina,18 A. Bzdak,13 H. Cherif,6 M. Ćirković,22 M. Csanad,7 J. Cybowska,17 T. Czopowicz,17 A. Damyanova,23 N. Davis,10 M. Deliyergiyev,9 M. Deveaux,6 A. Dmitriev,19 W. Dominik,15 P. Dorosz,13 J. Dumarchez,4 R. Engel,5 G. A. Feofilov,21 L. Fields,24 Z. Fodor,7,16 A. Garibov,1 M. Gaździcki,6,9 O. Golosov,20 M. Golubeva,18 K. Grebieszkow,17 F. Guber,18 A. Haesler,23 S. N. Igolkin,21 S. Ilieva,2 A. Ivashkin,18 S. R. Johnson,26 K. Kadija,3 E. Kaptur,14 N. Kargin,20 E. Kashirin,20 M. Kiełbowicz,10 V. A. Kireyeu,19 V. Klochkov,6 V. I. Kolesnikov,19 D. Kolev,2 A. Korzenev,23 V. N. Kovalenko,21 K. Kowalik,11 S. Kowalski,14 M. Koziel,6 A. Krasnoperov,19 W. Kucewicz,13 M. Kuich,15 A. Kurepin,18 D. Larsen,12 A. László,7 T. V. Lazareva,21 M. Lewicki,16 K. Łojek,12 B. Łysakowski,14 V. V. Lyubushkin,19 M. Maćkowiak-Pawłowska,17 Z. Majka,12 B. Maksiak,11 A. I. Malakhov,19 A. Marchionni,24 A. Marcinek,10 A. D. Marino,26 K. Marton,7 H.-J. Mathes,5 T. Matulewicz,15 V. Matveev,19 G. L. Melkumov,19 A. O. Merzlaya,12 B. Messerly,27 Ł. Mik,13 G. B. Mills,25 S. Morozov,18,20 S. Mrówczyński,9 Y. Nagai ,26 M. Naskręt,16 V. Ozvenchuk,10 V. Paolone,27 M. Pavin,4,3 O. Petukhov,18 R. Płaneta,12 P. Podlaski,15 B. A. Popov,19,4 B. Porfy,7 M. Posiadała-Zezula,15 D. S. Prokhorova,21 D. Pszczel,11 S. Puławski,14 J. Puzović,22 M. Ravonel,23 R. Renfordt,6 E. Richter-Wąs,12 D. Röhrich,8 E. Rondio,11 M. Roth,5 B. T. Rumberger,26 M. Rumyantsev,19 A. Rustamov,1,6 M. Rybczynski,9 A. Rybicki,10 A. Sadovsky,18 K. Schmidt,14 I. Selyuzhenkov,20 A. Yu. Seryakov,21 P. Seyboth,9 M. Słodkowski,17 A. Snoch,6 P. Staszel,12 G. Stefanek,9 J. Stepaniak,11 M. Strikhanov,20 H. Ströbele,6 T. Šuša,3 A. Taranenko,20 A. Tefelska,17 D. Tefelski,17 V. Tereshchenko,19 A. Toia,6 R. Tsenov,2 L. Turko,16 R. Ulrich,5 M. Unger,5 F. F. Valiev,21 D. Veberič,5 V. V. Vechernin,21 A. Wickremasinghe,27 Z.Włodarczyk,9 A.Wojtaszek-Szwarc,9 K. Wójcik,14 O.Wyszyński,12 L. Zambelli,4 E. D. Zimmerman,26 and R. Zwaska24 (NA61/SHINE Collaboration) 1National Nuclear Research Center, Baku, Azerbaijan 2Faculty of Physics, University of Sofia, Sofia, Bulgaria 3Rud¯er Bošković Institute, Zagreb, Croatia 4LPNHE, University of Paris VI and VII, Paris, France 5Karlsruhe Institute of Technology, Karlsruhe, Germany 6University of Frankfurt, Frankfurt, Germany 7Wigner Research Centre for Physics of the Hungarian Academy of Sciences, Budapest, Hungary 8University of Bergen, Bergen, Norway 9Jan Kochanowski University in Kielce, Poland 10Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland 11National Centre for Nuclear Research, Warsaw, Poland 12Jagiellonian University, Cracow, Poland 13AGH—University of Science and Technology, Cracow, Poland 14University of Silesia, Katowice, Poland 15University of Warsaw, Warsaw, Poland 16University of Wrocław, Wrocław, Poland 17Warsaw University of Technology, Warsaw, Poland 18Institute for Nuclear Research, Moscow, Russia 19Joint Institute for Nuclear Research, Dubna, Russia 20National Research Nuclear University (Moscow Engineering Physics Institute), Moscow, Russia 21St. Petersburg State University, St. Petersburg, Russia 22University of Belgrade, Belgrade, Serbia 23University of Geneva, Geneva, Switzerland 24Fermilab, Batavia, Illinois, USA 25Los Alamos National Laboratory, Los Alamos, New Mexico, USA 26University of Colorado, Boulder, Colorado, USA 27University of Pittsburgh, Pittsburgh, Pennsylvania, US

HS 0139+0559, HS 0229+8016, HS 0506+7725, and HS 0642+5049 : four new long-period cataclysmic variables

We present time-resolved optical spectroscopy and photometry of four relatively bright (V ∼ 14.0−15.5) long-period cataclysmic variables(CVs) discovered in the Hamburg Quasar Survey: HS 0139+0559, HS 0229+8016, HS 0506+7725, and HS 0642+5049. Their respective orbital periods, 243.69 ± 0.49 min, 232.550 ± 0.049 min, 212.7 ± 0.2 min, and 225.90 ± 0.23 min are determined from radial velocity and photometric variability studies. HS 0506+7725 is characterised by strong Balmer and He emission lines, short-period (∼10−20 min) flickering, and weak X-ray emission in the ROSAT All Sky Survey. The detection of a deep low state (B 18.5) identifies HS 0506+7725 as a member of the VY Scl stars. HS 0139+0559, HS 0229+8016, and HS 0642+5049 display thick-disc like spectra and no or only weak flickering activity. HS 0139+0559 and HS 0229+8016 exhibit clean quasi-sinusoidal radial velocity variations of their emission lines but no or very little orbital photometricvariability. In contrast, we detect no radial velocity variation in HS 0642+5049 but a noticeable orbital brightness variation. We identify all three systems either as UX UMa-type novalike variables or as Z Cam-type dwarf novae. Our identification of these four new systems underlines that the currently known sample of CVs is rather incomplete even for bright objects. The four new systems add to the clustering of orbital periods in the 3−4 h range found in the sample of HQS selected CVs, and we discuss the large incidence of magnetic CVs and VY Scl/SW Sex stars found in this period range among the known population of CVs

The First Detection of Blue Straggler Stars in the Milky Way Bulge

We report the first detections of Blue Straggler Stars (BSS) in the bulge of the Milky Way galaxy. Proper motions from extensive space-based observations along a single sight-line allow us to separate a sufficiently clean and well-characterized bulge sample that we are able to detect a small population of bulge objects in the region of the color-magnitude diagram commonly occupied young objects and blue strgglers. However, variability measurements of these objects clearly establish that a fraction of them are blue stragglers. Out of the 42 objects found in this region of the color-magnitude diagram, we estimate that at least 18 are genuine BSS. We normalize the BSS population by our estimate of the number of horizontal branch stars in the bulge in order to compare the bulge to other stellar systems. The BSS fraction is clearly discrepant from that found in stellar clusters. The blue straggler population of dwarf spheroidals remains a subject of debate; some authors claim an anticorrelation between the normalised blue straggler fraction and integrated light. If this trend is real, then the bulge may extend it by three orders of magnitude in mass. Conversely, we find that the genuinely young (~5Gy or younger) population in the bulge, must be at most 3.4% under the most conservative scenario for the BSS population.Comment: ApJ in press; 25 pages, 6 figures, 2 table