bluuebunny/crossref_metadata_2025_split huggingface dataset:
The future of fisheries oceanography lies in the pursuit of multiple hypotheses
Authors: Hare Jonathan A. 
Published: March 2014

AbstractFisheries oceanography is largely an applied discipline with a major goal of improving fisheries management and marine conservation. Johan Hjort's critical period hypothesis, and its decedents, remain a dominant theme and focuses on year-class success as mediated by prey availability and feeding. Bottom-up forcing, a related hypothesis, focuses on the sequential transfer of energy through the pelagic foodweb from primary productivity to fishery productivity. Another approach assumes that trophic interactions of adults determine abundance. Fisheries assessment and management, however, is based on the hypothesis that fishery abundance is determined by time-varying fishing and year-class success related to spawning-stock biomass. These approaches, their basic hypotheses, and underlying processes and mechanisms suggest very different dynamics for fishery populations. Other hypotheses challenge these traditional views: predation of early life stages, parental condition, shifting migration pathways, and physiological limits. Support for these other hypotheses is reviewed and the research needs are described to apply these hypotheses to fisheries assessment and management. Some of these hypotheses were identified by Hjort (e.g. parental condition hypothesis) and others are relative new (e.g. early life stage predation hypothesis). Moving into the future, we should focus on Hjort's approach: multi-hypothesis, integrative, and interdisciplinary. A range of hypotheses should be pursued with an emphasis on comparing and linking multiple hypotheses. The results then must be incorporated into fishery assessments and management decisions to support the long-term sustainability of exploited species and the conservation of threatened and endangered species.
Why the complex nature of integrated ecosystem assessments requires a flexible and adaptive approach
Authors: Dickey-Collas Mark 
Published: March 2014

Abstract
This article considers the approach taken by the ICES to integrated ecosystem assessments (IEAs) in the context of the wider evolution of IEAs and the science/policy landscape within the ICES region. It looks forward and considers the challenges facing the development of IEAs, specifically those of scoping for objectives, participatory engagement, developing indicators and targets, risk analysis, and creating tools to evaluate management measures for marine anthropogenic activities. It concludes that expectations that the implementation of IEAs will take an ordered, stepwise approach will lead to disappointment and frustration. This is a consequence of the need to operate in an adaptive manner in a complex system. The ecosystem, the science support infrastructure, and the governance systems are all complex. Plus when engaged in a debate about societal objectives, we expect to encounter a complex and changing landscape. As a community, the challenge is to find leverage mechanisms to encourage IEA efforts to provide insights and tools within resources. We will need to innovate and be responsive to the complexity of the ecosystem and governance structures encountered when performing IEA.
Long-Term Conservation of Adiabatic Invariants by Using Symplectic Integrators
Authors: Shimada Masaaki , Yoshida Haruo 
Published: March 2014

Abstract
The advantage of symplectic integrators compared with non-symplectic Runge-Kutta integrators is shown in the computation of adiabatic invariants. Symplectic integrators do not produce a secular growth of the error, contrary to non-symplectic Runge-Kutta integrators. Furthermore, we compared the performance of 2nd, 4th, and 6th order symplectic integrators and obtained the numerical results that show SI6 has the best performance when the numerical error in the adiabatic invariants must be below 0.03%. The model systems that we used are a one-dimensional harmonic oscillator with a slowly varying frequency and a one-particle system in a slowly varying isochrone potential.
CO Observations of a Galaxy behind the Galactic Plane, Dwingeloo 1
Authors: Kuno Nario , Vila-Vilaró Baltasar , Nishiyama Kohta 
Published: March 2014

Abstract
We have observed Dwingeloo 1, which was discovered behind the disk of the Milky Way in 1994, in the CO (J = 1−0) line transition with the Nobeyama 45-m telescope. We detected very weak CO line emission in the optical bar and marginally at the center. The surface density of molecular gas derived using the Galactic conversion factor N(H2)/ICO = 2.6 × 1020 in only 8.4 M⊙ pc-2, correcting for the inclination of the galaxy even in the center. The central surface density of molecular gas and the M(H2)/M(H I) ratio indicate that Dwingeloo 1 is a molecular gas-poor galaxy.
Nonlinear Pulsation Driven by Strange Modes in Hydrodynamic Models
Authors: Aikawa Toshiki , Sreenivasan S. Ranga 
Published: March 2014

Abstract
The characteristics of the nonlinear pulsation of hydrodynamic models, which have only strange modes as pulsational unstable modes, are compared with those by conventional modes. It is shown that nonlinear pulsation with the strange modes has considerable amplitudes only at the hydrogen ionization zone and in the atmosphere. This is sharp in contrast to that by conventional modes, and is identical with the characteristics of the unstable linear strange modes. We thus conclude that the unstable strange modes may be responsible for the nonlinear pulsation. We also discuss the physical origin of the instability of the strange modes. Since the modes are pulsationally unstable without any luminosity perturbation, other physical mechanisms must be involved for the instability along with the conventional kappa and gamma mechanisms, which are familiar in Cepheid variables. We suggest that the density inversion in the H ionization region, including the adjacent He I ionization zone, may be the origin. Finally, we suggest that the different pulsation driving zones may cause the feature of the spatial amplitude variations.
Global 3- and 7-mm VLBI Observations of OJ 287
Authors: Tateyama Claudio E. , Inoue Makoto , Krichbaum Thomas P. , Bååth Lars B. , Kameno Seiji , Rogers Alan E. E. , Alberdi Antonio , Backer Don C. , Bartel Norbert , Booth Roy S. , Burke Bernard F. , Carlstrom John E. , Dhawan Vivek , Dickman Robert L. , Emerson Darrel T. , Hirabayashi Hisashi , Hodges Mark W. , Graham David A. , Johnston Kenneth J. , Kobayashi Hideyuki , Kus Andrzej J. , Padin Stephen , Plambeck Richard L. , Predmore C. Read , Quirrenbach Andreas , Lawrence Charles R. , Lamb James , Marcaide Juan M. , Morimoto Masak , Ronnang Bernt O. , Shapiro Irwin I. , Spencer John H. , Witzel Arno , Woody David , Wright Melvyn C. H. 
Published: March 2014

Abstract
We present new results from global VLBI observations of the highly active blazar OJ 287 at 7 and 3 mm wavelengths. We show the first map of the mas to sub-mas structure of OJ 287 at 43 GHz and discuss this image in the context with models of the source structure seen at 100 GHz.
Large-Amplitude Superhumps in ER Ursae Majoris during the Earliest Stage of a Superoutburst
Authors: Kato Taichi , Nogami Daisaku , Masuda Seiji 
Published: March 2014

Abstract
Time-resolved CCD photometry of a peculiar SU UMa-type dwarf nova, ER UMa, during the earliest stage of superoutbursts revealed the existence of large-amplitude (˜ 0.35 mag) superhumps. These superhumps appear at, or even during, the rise to the superoutburst maximum, and show a rapid decay of amplitudes with a time scale of a few days. After a period showing a low-amplitude variation, superhumps with more usual singly-peaked profiles appear in the later stage of the superoutburst. Such an early appearance of superhumps seems to contradict the current growth model of superhumps or tidal instability, whose growth rate has been shown to be proportional to the square of the binary mass ratio. Several possibilities to explain this anomaly are also briefly discussed, as well as a comparison with other early stage superhumps in WZ Sge stars.
Ion Tail Disturbance of Comet C/Hyakutake 1996B2 Observed around the Closest Approach to the Earth
Authors: Kinoshita Daisuke , Fukushima Hideo , Watanabe Jun-ichi , Yamamoto Naotaka 
Published: March 2014

Abstract
A sequential imaging observation of the ion tail of Comet C/Hyakutake 1996B2 was carried out on 1996 March 25 with a wide-field CCD imaging camera developed at the National Astronomical Observatory of Japan. We detected a peculiar knot receding along the main axis of the ion tail during our observation. This knot was located at 5.0 × 106 km from the nucleus on March 25.6 UT, and moved about 2.0 × 106 km during 5 hr. The measured velocity along the axis of the ion tail was derived to be 99.2 ± 0.3 km s−1 , which is almost constant within the observational limit. We also measured the perpendicular motion of this knot to the axis, and identified rapid acceleration. The brightness of the knot decreased during the observation. We report on preliminary results of an analysis of this phenomenon, and discuss some characteristics in this paper.
Two-Dimensional Accretion Disks at Subcritical Luminosity
Authors: Fujita Mitsutaka , Okuda Toru 
Published: March 2014

Abstract
To examine subcritical accretion disks, we performed two-dimensional axisymmetric calculations by solving a set of fully non-linear hydrodynamic equations coupled with radiation transport. Focusing on the accretion disks of neutron stars near to the Eddington luminosity LE, we obtained thermally stable accretion disks where the radiation pressure and electron scattering are dominant. The thermally stable disks are interpreted in terms of the slim accretion-disk theory. While the accretion disks are unstable to convection and convective cells generally stretch from the disk mid-plane to the disk surface in the inner disk. It has been found that convection is an important energy-transfer mechanism along the vertical direction of the disk. A very rarefied, hot, and optically thin region is formed along the rotational axis of the disk. The relativistic jet with a collimation angle of less than 10° is generated in the rarefied optically thin region, mainly due to the dominant radiation-pressure force. The results of subcritical accretion onto a neutron star are discussed in relation to SS 433.
Radiation Hydrodynamical Mass Accretion onto Galactic Nuclei Driven by Circumnuclear Starbursts
Authors: Ohsuga Ken , Umemura Masayuki , Fukue Jun , Mineshige Shin 
Published: March 2014

Abstract
We explore the radiation hydrodynamical evolution of a galactic nuclear gas disk exposed to intense radiation from circumnuclear starbursts. The evolution is characterized by two stages. First, the disk is radially contracted by the radiation force. Subsequently, the surface stratum of the disk avalanches onto the center due to the removal of angular momenta by radiation drag. The mass accretion via a radiatively-driven avalanche was analyzed quantitatively while assuming a torus shape of the circumnuclear starburst regions. As a result, it was found that the mass-accretion rate is sensitively dependent upon the extension of the starburst regions. For an optically thick disk, the mass-accretion rate is roughly in proportion to the ratio of the thickness to the curvature radius of the torus. The rate is also dependent upon the rotation law of the disk. We investigated the evolution of the disk surface density resulting from radiatively-driven mass accretion. It was found that for a more intensive starburst the central concentration of surface density becomes more conspicuous. The present results seem to be significant when considering the evolution of starburst nuclei, for instance, in luminous IRAS galaxies.
Discovery of a New X-Ray Pulsar, AX J0049-729, in the Small Magellanic Cloud with ASCA
Authors: Yokogawa Jun , Imanishi Kensuke , Tsujimoto Masahiro , Kohno Makoto , Koyama Katsuji 
Published: March 2014

Abstract
We report on the results of two ASCA observations on an X^ray source, AX J0049–729 (= RX J0049.1–7250), in the Small Magellanic Cloud. A sinusoidal pulsation with a barycentric period of 74.676±0.022 s was found. The pulse fraction was ∼ 70%, independent of the X-ray energy. The spectrum was hard with an absorbed power-law having a photon index of ∼ 1. The X-ray flux was 1.1×10−11 erg s−1 cm−2, and then declined to 1.6×10∼12 erg s−1 cm−2 from the first to the second observations, separated by about one month. Together with the previous results of the Einstein and ROSAT satellites, we found that AX J0049–729 has been in quiescent states, but occasionally showing flare activities. The flux variability, long-pulse period, and hard spectrum support the idea that AX J0049-729 is an X-ray binary pulsar, most likely a Be star binary.
A Quadruple Magnetic Source Model for Arcade Flares and X-Ray Arcade Formations outside Active Regions I. Dark Filament Suspension and the Magnetic Structure in the Pre-Event Regions
Authors: Uchida Yutaka , Hirose Shigenobu , Cable Samuel , Morita Satoshi , Torii Masaya , Uemura Shuhei , Yamaguchi Tomotaka 
Published: March 2014

Abstract
The high-sensitivity, wide dynamic-range observations by the Soft X-ray Telescope (SXT) aboard Yohkoh has enabled us to look into the faint pre-event structures of arcade flares, and of even fainter X-ray arcade formation events outside active regions. What we have found in the pre-event structure of the latter, however, was not a sagged simple (bipolar) arcade, as expected in the classical model, but a “dual-arcades„ type structure in which the inside legs of each “arcade„ cross with the other's, landing at the closer part of the domain of the other. Similar features, together with some other features inexplicable in the classical arcade flare model, were also found in strong arcade flares in active regions seen axis-on at the limb. These features raised a severe problem with the classical “reclosing of the once opened simple arcade„ model(s). In the present paper, we propose interpretations of what we discovered by Yohkoh-SXT by reviving a quadruple source model proposed by one of the authors (YU) years ago, pointing out a serious difficulty in the classical model(s). This model, based on the quadruple magnetic sources in the photosphere, has a “neutral sheet„ already in the pre-event phase in the corona above the field polarity-reversal line in the photosphere, and turns out to explain quite nicely the structures of both faint pre-event corona before arcade formation events, and that of arcade flares discovered by Yohkoh-SXT. A dynamic model of arcade flares and arcade formation events based on this dark filament model will be discussed in the forthcoming Paper II of this series.
Discovery of the Carina Flare with NANTEN; Evidence for a Supershell That Triggered the Formation of Stars and Massive Molecular Clouds
Authors: Fukui Yasuo , Onishi Toshikazu , Abe Rihei , Kawamura Akiko , Tachihara Kengo , Yamaguchi Reiko , Mizuno Akira , Ogawa Hideo 
Published: March 2014

Abstract
We present extensive observations of the Carina arm region in the 2.6 mm CO (J = 1−0) emission with the NANTEN telescope in Chile. The observations have revealed 120 molecular clouds which are distributed in an area of 283° &lt; l &lt; 293° and 2° .5 &lt; b &lt; 10°. Because of its vertical elongation to the galactic plane, the clouds are named the Carina flare. H I and far-infrared emission show a cavity-like distribution corresponding to the molecular clouds, and soft X-ray emission appears to fill this cavity. It is shown that the Carina flare represents a supershell at a distance of a few kpc that has been produced by about 20 supernova explosions, or equivalent stellar winds of OB stars, over the last ∼ 2×107 yr. The supershell consisting of molecular and atomic neutral gas involves a total mass and kinetic energy of ≳ 3×105M⊙ and ≳ 3×1050 erg, respectively, and the originally injected energy required is about 100-times this current kinetic energy in the shell. It is unique among supershells known previously because of the following aspects: i) it exhibits evidence for the triggered formation of intermediate-to-high-mass stars and massive molecular clouds of 102 − 104M⊙, and ii) the massive molecular clouds formed are located unusually far above the galactic plane at z ∼ 100–500 pc.
Molecular Clouds and Star Formation in the Southern H II Regions
Authors: Yamaguchi Reiko , Saito Hiro , Mizuno Norikazu , Mine Yoshihiro , Mizuno Akira , Ogawa Hideo , Fukui Yasuo 
Published: March 2014

Abstract
We have carried out extensive 13CO(J = 1−0) observations toward 23 southern H II regions associated with bright-rimmed clouds. In total, 95 molecular clouds have been identified to be associated with the H II regions. Among the 95, 57 clouds \ are found to be associated with 204 IRAS point sources which are candidates for young stellar objects. There is a significant increase of star-formation efficiency on the side facing to the H II regions; the luminosity-to-mass ratio, defined as the ratio of the stellar luminosity to the molecular cloud mass, is higher by an order of magnitude on the near side of the H II regions than that on the far side. This indicates that molecular gas facing to the H II regions is more actively forming massive s\ tars whose luminosity is ≳103L⊙. In addition, the number density of the IRAS point sources increases by a factor of 2 on the near side of the H II regions compared with on the far side. These results strongly suggest that the active formation of massive stars on the near side of the H II regions is due to the effects of the H II regions, such as the compression of molecular material by the ionization/shock fronts. For the whole Galaxy, we estimate that the present star-formation rate under such effects is at least 0.2−0.4 M⊙ yr-1, corresponding to a few 10% by mass.
Ab Initio Calculations for Detectable New Isomers of Interstellar Carbon-Chain Radicals Cn(n=2–8)
Authors: Takahashi Junko 
Published: March 2014

Abstract
Detectable new isomers of interstellar carbon-chain (linear) radicals, Cn(n=2–8), were investigated theoretically based on ab initio quantum chemical calculations. The molecular characteristics of various Cn(n=3–8) isomers were examined, and it was found that 3-ring isomers (isomers with a three-member-carbon-ring) of C3H, C5H, and C7H are at a low energy level relative to linear isomers, and that their dipole moments are sufficiently large. The formation mechanisms of C3H and C5H were also examined, and it was found that both linear- and 3-ring-C3H and C5H can be formed via neutral-neutral reactions, C + C2H2 → C3H + H and C + C4H2 → C5H + H, respectively, in interstellar space. These facts strongly suggest that carbon-ring-chain radicals, C5H and C7H, are a new series of interstellar molecules that will be detectable in the laboratory and interstellar space.
Radix-4 Butterfly LSI in Direct-Imaging Waseda Radio Interferometer for a Pulsar Survey
Authors: Tanaka Naoki , Daishido Tsuneaki , Takeuchi Hiroshi , Akamine Yukinori , Kuniyoshi Masaya , Suemitsu Taisei , Fujii Fumiyuki , Gotoh Kentaro , Suzuki Tomoya , Mizuki Saori , Mizuno Keiju , Fukuoka Koji , Suzuki Masahiro 
Published: March 2014

Abstract
In the Nyquist rate direct-imaging interferometer at Waseda University, a radix-4 butterfly LSI has been developed for the spatial-temporal (2+1)D FFT processor to survey pulsars. In (2+1)D FFT, the first 2D FFT is a 2D directional finding spatial FFT processing for an 8times 8 pixel image. The second 1D FFT is a 1D spectral finding temporal FFT processing for a 64ch frequency analysis in each 64 pixels. Since fewer multipliers are required in radix-4 FFT than in radix-2 FFT, we have implemented radix-4 algorithms in the present butterfly LSI. This implementation, using 512 radix-4 butterfly LSIs, could reduce the circuit size of the parallel and pipeline (2+1)D FFT processor. Additional functions, such as shift registers, digital filters and post-process sections, are also included in the LSI for a radio interferometric pulsar survey.
Magnetic Field Evolution Leading to Solar Flares I. Cases with Low Magnetic Shear and Flux Emergence
Authors: Li Hui , Sakurai Takashi , Ichimoto Kiyoshi , UeNo Satoru 
Published: March 2014

Abstract
We picked up five solar flares larger than GOES X-ray class M/Hα importance 1, and studied the magnetic evolution of the corresponding active regions. In particular, we investigated the spatial relationships among Hα flare ribbons, soft X-ray (SXR) flare loops, and magnetic configurations. Our results show that all of these flares are not associated with high magnetic shear, but with emerging flux, indicating that flux emergence is a common phenomenon in this kind of solar flare with low magnetic shear. The maximum values of the transverse magnetic fields on the neutral lines responsible for these flares are 300-800 G. All of these flares but one have multiple (more than two) Hα ribbons, and almost all of these ribbons are located at the footpoints of SXR flare loops. The flare-related shear changes, which can be both positive and negative, may be determined by the balance of the energy carried by the emerging flux and that required to power the flare.
Distribution and Kinematics of Molecular Gas in Barred Spiral Galaxies. I. NGC 3504
Authors: Kuno Nario , Nishiyama Kohta , Nakai Naomasa , Sorai Kazuo , Vila-Vilaró Baltasar , Handa Toshihiro 
Published: March 2014

Abstract
We present the results of CO mapping observations of the barred spiral galaxy NGC 3504 with the Nobeyama 45-m telescope. The distribution of the molecular gas shows offset ridges which correspond to the distribution of H II regions along the bar. The velocity perpendicular to the bar decreases abruptly at the ridge. The velocity change implies that the molecular gas changes the direction of its motion to parallel to the bar at the ridge. Since the position angle of the major axis of the bar and the line of nodes are almost the same in NGC 3504, an upper limit to the pattern speed of the bar can be derived directly from the radial velocity. The resultant upper limit is 41 km s−1 kpc−1, which is much smaller than that derived based on an assumption that the corotation radius is located at the end of the bar (77 km s−1 kpc−1). The corotation radius derived from our upper limit is more than two-times larger than the length of the semi-ma jor axis of the bar in NGC 3504.
Discovery of 172-s Pulsations from a Be/X-Ray Binary Candidate AX J0051.6–7311 in the SMC with ASCA
Authors: Yokogawa Jun , Torii Ken'ichi , Imanishi Kensuke , Koyama Katsuji 
Published: March 2014

Abstract
The results from three ASCA observations of AX J0051.6–7311 = RX J0051.9–7311 are reported. Coherent pulsations with a barycentric period of 172.40 ± 0.03 s were discovered in the third observation, with an exceptionally long exposure time of ∼ 177 ks. The X-ray spectrum was found to remain unchanged through these observations, with a photon index of of ∼ 0.9. Energy-resolved pulse profiles in the third observation reveal that the pulsations are mostly due to photons with an energy above ∼ 2 keV. Archival data of ROSAT and Einstein Observatory indicate that AX J0051.6–7311 exhibits a flux variation having a factor ≳ 20.
The Time Lag between V and I in S5 0716+714 during the 1995 January 8 Burst
Authors: Qian Bochen , Tao Jun , Fan Junhui 
Published: March 2014

Abstract
The BL Lac object S5 0716+714 has been one part of our optical monitoring program of blazars since 1994. A burst with a duration of 6 hours was detected on 1995 January 8 and 80 sets of measurements were obtained in V and I, by turn, for the whole burst. An upper limit of the time lag of 0.0041 days (about six minutes) between bands V and I has been determined by using the Interpolation Cross-Correlation Function (ICCF) and the Discrete Correlation Function (DCF).