1,378 research outputs found
Constraints from Unrealistic Vacua in Supersymmetric Standard Model with Neutrino Mass Operators
We analyze a scalar potential of the minimal supersymmetric standard model
(MSSM) with neutrino mass operators along Unbounded-From-Below (UFB) and Color
and/or Charged Breaking (CCB) directions. We show necessary conditions to avoid
the potential minima which can be deeper than the realistic vacuum. These
conditions would constrain more strongly than conditions in the MSSM without
taking into account neutrino mass operators, and can improve the predictive
power of supersymmetric models with neutrino mass operators.Comment: 11 pages, 4 figure
Quantum dots as a probe of fundamental physics: Deviation from exponential decay law
We explore a possibility of measuring deviation from the exponential decay
law in pure quantum systems. The power law behavior at late times of decay time
profile is predicted in quantum mechanics, and has been experimentally
attempted to detect, but with failures except a claim in an open system. It is
found that electron tunneling from resonance state confined in man-made atoms,
quantum dots, has a good chance of detecting the deviation and testing
theoretical predictions. How initial unstable state is prepared influences
greatly the time profile of decay law, and this can be used to set the onset
time of the power law at earlier times. Comparison with similar process of
nuclear alpha decay to discover the deviation is discussed, to explain why
there exists a difficulty in this case.Comment: 21 pages, 12 figure
Decision Analysis in a Fishing Port Project Using Multi-attribute Utility Theory
In order to attain the goal of an overall project evaluation of a fishing port project, a conceptual approach has been established in this paper, using a multi-attribute utility theory. As a first step, the multiple attributes relevant to a fishing port project have been formulated. Based on these attributes, a basic approach to the overall evaluation of a fishing port project has further been sought through developing an evaluation model in the form of a flow chart. It is pointed out that an application of such methodology can only be made a concrete and detailed proposal which is quite often the case presented by the concerned authority for the consideration of a financial institution. In the past, many researchers in this field contributed their efforts to the approach and methodology for the preparation of a feasibility study through presenting and examining various alternative proposals. However, the evaluation of the detailed proposal based on an already completed feasibility study which was carried out by the other party, was hardly given consideration. In order to actually test the methodology and approach, an actual project proposal case has been taken from the Seo Geo Cha fishing port project in Korea, through which presented steps were examined
Dinitrogen-Fixing Cyanobacteria in Microbial Mats of Two Shallow Coral Reef Ecosystems
Dinitrogen-fixing organisms in cyanobacterial mats were studied in two shallow coral reef ecosystems: La Reunion Island, southwestern Indian Ocean, Sesoko (Okinawa) Island, and northwestern Pacific Ocean. Rapidly expanding benthic miniblooms, frequently dominated by a single cyanobacterial taxon, were identified by microscopy and molecular tools. In addition, nitrogenase activity by these blooms was measured in situ. Dinitrogen fixation and its contribution to mat primary production were calculated using 15N2 and 13C methods. Dinitrogen-fixing cyanobacteria from mats in La Reunion and Sesoko showed few differences in taxonomic composition. Anabaena sp. among heterocystous and Hydrocoleum majus and Symploca hydnoides among nonheterocystous cyanobacteria occurred in microbial mats of both sites. Oscillatoria bonnemaisonii and Leptolyngbya spp. occurred only in La Reunion, whereas Hydrocoleum coccineum dominated in Sesoko. Other mats dominated by Hydrocoleum lyngbyaceum, Phormidium laysanense, and Trichocoleus tenerrimus occurred at lower frequencies. The 24-h nitrogenase activity, as measured by acetylene reduction, varied between 11 and 324 nmoles C2H2 reduced ”gâ1 Chl a. The highest values were achieved by heterocystous Anabaena sp. performed mostly during the day. Highest values for nonheterocystous cyanobacteria were achieved by H. coccineum mostly during the night. Daily nitrogen fixation varied from nine (Leptolyngbya) to 238 nmoles N2”gâ1 Chl dayâ1 (H. coccineum). Primary production rates ranged from 1,321 (S. hydnoides) to 9,933 nmoles C ”gâ1 Chl dayâ1 (H. coccineum). Dinitrogen fixation satisfied between 5% and 21% of the nitrogen required for primary production.Ocean Development Sub-Committee of FranceâJapan S&T Cooperation; Mitsubishi cooperation; The Ministry of Education, Science, Sport, and Culture of Japan; Hanse Wissenschaftskolleg; Delmenhorst and Alexander-von-Humboldt Foundation; Bad Godesberg; Germany supported collaborative research on cyanobacterial diversit
High Angular Resolution, Sensitive CS J=2-1 and J=3-2 Imaging of the Protostar L1551 NE: Evidence for Outflow-Triggered Star Formation ?
High angular resolution and sensitive aperture synthesis observations of CS
() and CS () emissions toward L1551 NE, the second brightest
protostar in the Taurus Molecular Cloud, made with the Nobeyama Millimeter
Array are presented. L1551 NE is categorized as a class 0 object deeply
embedded in the red-shifted outflow lobe of L1551 IRS 5. Previous studies of
the L1551 NE region in CS emission revealed the presence of shell-like
components open toward L1551 IRS 5, which seem to trace low-velocity shocks in
the swept-up shell driven by the outflow from L1551 IRS 5. In this study,
significant CS emission around L1551 NE was detected at the eastern tip of the
swept-up shell from = 5.3 km s to 10.1 km s, and
the total mass of the dense gas is estimated to be 0.18 0.02 .
Additionally, the following new structures were successfully revealed: a
compact disklike component with a size of 1000 AU just at L1551 NE,
an arc-shaped structure around L1551 NE, open toward L1551 NE, with a size of
AU, i.e., a bow shock, and a distinct velocity gradient of the
dense gas, i.e., deceleration along the outflow axis of L1551 IRS 5. These
features suggest that the CS emission traces the post-shocked region where the
dense gas associated with L1551 NE and the swept-up shell of the outflow from
L1551 IRS 5 interact. Since the age of L1551 NE is comparable to the timescale
of the interaction, it is plausible that the formation of L1551 NE was induced
by the outflow impact. The compact structure of L1551 NE with a tiny envelope
was also revealed, suggesting that the outer envelope of L1551 NE has been
blown off by the outflow from L1551 IRS 5.Comment: 29 pages, 12 figures, Accepted for Publication in the Astrophysical
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