774 research outputs found
Pentaquark state in pole-dominated QCD sum rules
We propose a new approach in QCD sum rules applied for exotic hadrons with a
number of quarks, exemplifying the pentaquark Theta^{+} (I=0,J=1/2) in the
Borel sum rule. Our approach enables reliable extraction of the pentaquark
properties from the sum rule with good stability in a remarkably wide Borel
window. The appearance of its valid window originates from a favorable setup of
the correlation functions with the aid of it chirality of the interpolating
fields on the analogy of the Weinberg sum rule for the vector currents. Our
setup leads to large suppression of the continuum contributions which have
spoiled the Borel stability in the previous analyses, and consequently enhances
importance of the higher-dimensional contributions of the OPE, which are
indispensable for investigating the pentaquark properties. Implementing the OPE
analysis up to dimension 15, we find that the sum rules for the chiral-even and
odd parts independently give the Theta^{+} mass of 1.68 pm 0.22 GeV with
uncertainties of the condensate values. Our sum rule indeed gives rather flat
Borel curves almost independent of the continuum thresholds both for the mass
and pole residue. Finally, we also discuss possible isolation of the observed
states from the KN scattering state on view of chiral symmetry.Comment: 8 pages, 7 figure
Monopole Oscillations and Dampings in Boson and Fermion Mixture in the Time-Dependent Gross-Pitaevskii and Vlasov Equations
We construct a dynamical model for the time evolution of the boson-fermion
coexistence system. The dynamics of bosons and fermions are formulated with the
time-dependent Gross-Pitaevsky equation and the Vlasov equation. We thus study
the monopole oscillation in the bose-fermi mixture. We find that large damping
exists for fermion oscillations in the mixed system even at zero temperature.Comment: 16 pages text and 12 figure
QNDE Topical Forum Total Quality Management â TQM
The emerging world economy presents challenges to all industrial nations in productivity, product reliability and customer confidence level. The challenges are being met in various nations by reorienting industries for the production and marketing of âworld classâ products. Such reorientation requires significant cultural changes, significant improvements in management and judicious implementation of new and developing technologies. Reorientation to âworld classâ production has been implemented in the United States of America by a Department of Defense initiative that is known as âTotal Quality Management or TQMâ
Fluctuation properties of strength functions associated with giant resonances
We performed fluctuation analysis by means of the local scaling dimension for
the strength function of the isoscalar (IS) and the isovector (IV) giant
quadrupole resonances (GQR) in Ca, where the strength functions are
obtained by the shell model calculation within up to the 2p2h configurations.
It is found that at small energy scale, fluctuation of the strength function
almost obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit.
On the other hand, we found a deviation from the GOE limit at the intermediate
energy scale about 1.7MeV for the IS and at 0.9MeV for the IV. The results
imply that different types of fluctuations coexist at different energy scales.
Detailed analysis strongly suggests that GOE fluctuation at small energy scale
is due to the complicated nature of 2p2h states and that fluctuation at the
intermediate energy scale is associated with the spreading width of the
Tamm-Dancoff 1p1h states.Comment: 14 pages including 13figure
Detailed analysis of the gluonic excitation in the three-quark system in lattice QCD
We study the excited-state potential and the gluonic excitation in the static
three-quark (3Q) system using SU(3) lattice QCD with at
=5.8 and 6.0 at the quenched level. For about 100 different patterns of
spatially-fixed 3Q systems, we accurately extract the excited-state potential
together with the ground-state potential by diagonalizing the QCD Hamiltonian in the presence of three
quarks. The gluonic excitation energy is found to be about 1 GeV at the typical hadronic
scale. This large gluonic-excitation energy is conjectured to give a physical
reason of the success of the quark model for low-lying hadrons even without
explicit gluonic modes. We investigate the functional form of in terms of the 3Q location. The lattice data of are
relatively well reproduced by the ``inverse Mercedes Ansatz'' with the
``modified Y-type flux-tube length'', which indicates that the
gluonic-excitation mode is realized as a complicated bulk excitation of the
whole 3Q system.Comment: 13pages, 13figure
Possible activation of the immune system by chronic peripheral nesfatin-1 application at the acute phase of ischemia/reperfusion injury
Objective: Organ transplantation is one of the clinical scenarios involving ischemia and reperfusion process. Ischemia/reperfusion is the pivotal mechanism of organ injury during transplantation. Thus, ischemia/reperfusion (I/R) injury is a biphasic phenomenon that can damage the graft by inflammatory responses. The hypothalamic-pituitary-adrenal (HPA) axis is the main hormonal system that is activated under the inïŹuence of stress. Normal HPA axis activity leading to the release of glucocorticoids is essential for homeostasis and survival during stress. Cortisol, a key controller of stress response, is released by the HPA axis. The disrupted release of cortisol in response to inflammation has been shown in animal models. Nesfatin-1 is a peptide involved in the regulation of homeostasis and has anti-inflammatory as well as anti-ischemic properties. Therefore, we aimed to identify the effect of chronic peripheral nesfatin-1 application on the plasma level of cortisol in a rat model of intestinal I/R-based stress. Materials and Methods: Two-month-old 28 Wistar Albino male rats that weighed an average of 200â250 g were used and were randomly divided into the following four experimental groups (n=7): laparotomy, I/R, nesfatin-1+laparotomy, nesfatin-1+I/R. Blood samples were collected in tubes with EDTA. Plasma cortisol levels were analyzed by rat enzyme-linked immunosorbent assay (ELISA) kits. Results: Statistically significant decrease was found in the plasma level of cortisol in nesfatin-1+I/R group compared with I/R group (p=0.026) Conclusion: Nesfatin-1 application can inhibit anti-inflammatory responses under the early phase of intestinal I/R and support immune reactions by reducing plasma cortisol level. This effect of nesfatin-1 may also increase the rejection of grafts during transplantation period. © 2015 by Erciyes University School of Medicine
Dissipative Field Theory with Caldeira-Leggett Method and its Application to Disoriented Chiral Condensation
The effective field theory including the dissipative effect is developed
based on the Caldeira-Leggett theory at the classical level. After the
integration of the small field fluctuations considered as the field radiation,
the integro-differential field equation is given and shown to include the
dissipative effects. In that derivation, special cares should be taken for the
boundary condition of the integration. Application to the linear sigma model is
given, and the decay process of the chiral condensate is calculated with it,
both analytically in the linear approximation and numerically. With these
results, we discuss the stability of chiral condensates within the quenched
approximation.Comment: 16pages, ReV-Te
Bacterial vs. zooplankton control of sinking particle flux in the ocean\u27s twilight zone
The downward flux of particulate organic carbon (POC) decreases significantly in the oceanĂs mesopelagic or âtwilightâ zone due both to abiotic processes and metabolism by resident biota. Bacteria and zooplankton solubilize and consume POC to support their metabolism, but the relative importance of bacteria vs. zooplankton in the consumption of sinking particles in the twilight zone is unknown. We compared losses of sinking POC, using differences in export flux measured by neutrally buoyant sediment traps at a range of depths, with bacteria and zooplankton metabolic requirements at the Hawaii Ocean Timeâseries station ALOHA in the subtropical Pacific and the Japanese timesâseries site K2 in the subarctic Pacific. Integrated (150â1,000 m) mesopelagic bacterial C demand exceeded that of zooplankton by up to 3âfold at ALOHA, while bacteria and zooplankton required relatively equal amounts of POC at K2. However, sinking POC flux was inadequate to meet metabolic demands at either site. Mesopelagic bacterial C demand was 3â to 4âfold (ALOHA), and 10âfold (K2) greater than the loss of sinking POC flux, while zooplankton C demand was 1â to 2âfold (ALOHA), and 3â to 9âfold (K2) greater (using our âmiddleâ estimate conversion factors to calculate C demand). Assuming the particle flux estimates are accurate, we posit that this additional C demand must be met by diel vertical migration of zooplankton feeding at the surface and by carnivory at depthĂâwith both processes ultimately supplying organic C to mesopelagic bacteria. These pathways need to be incorporated into biogeochemical models that predict global C sequestration in the deep sea
Sustainable forest bioenergy development strategies in Indochina: Collaborative effort to establish regional policies
We conducted a feasibility study in Indochina (Cambodia, Laos, Myanmar, Thailand, and Vietnam) with the aim of promoting biomass and bioenergy markets, technology transfer, rural development, and income generation. Policy development is guided by the International Union of Forest Research Institutions (IUFRO) Task Force âSustainable Forest Bioenergy Networkâ. In this paper, we highlight the achievements up to now and present results of a multi-stakeholder questionnaire in combination with a quantitative analysis of the National Bioenergy Development Plans (NBDPs). We found a gap between official documents and working group assessments. NBDPs are focused on the market development, technology transfer, and funding possibilities of a regional bioenergy strategy, while the respondents of a questionnaire (working groups) favored more altruistic goals, i.e., sustainable resource management, environmental protection and climate change mitigation, generation of rural income, and community involvement, etc. We therefore suggest the following measures to ensure regulations that support the original aims of the network (climate change mitigation, poverty alleviation, sustainable resource use, and diversification of energy generation): (i) Consideration of science-based evidence for drafting bioenergy policies, particularly in the field of biomass production and harvesting; (ii) invitation of stakeholders representing rural communities to participate in this process; (iii) development of sustainability criteria; (iv) feedback cycles ensuring more intensive discussion of policy drafts; (v) association of an international board of experts to provide scientifically sound feedback and input; and (vi) establishment of a local demonstration region, containing various steps in the biomass/bioenergy supply chain including transboundary collaboration in the ACMECS region
Optical Identification of the ASCA Large Sky Survey
We present results of optical identification of the X-ray sources detected in
the ASCA Large Sky Survey. Optical spectroscopic observations were done for 34
X-ray sources which were detected with the SIS in the 2-7 keV band above 3.5
sigma. The sources are identified with 30 AGNs, 2 clusters of galaxies, and 1
galactic star. Only 1 source is still unidentified. The flux limit of the
sample corresponds to 1 x 10^{-13} erg s^{-1} cm^{-2} in the 2-10 keV band.
Based on the sample, the paper discusses optical and X-ray spectral
properties of the AGNs, contribution of the sources to the Cosmic X-ray
Background, and redshift and luminosity distributions of the AGNs. An
interesting result is that the redshift distribution of the AGNs suggests a
deficiency of high-redshift (0.5 10^{44}
erg s^{-1}) absorbed narrow-line AGNs (so called type 2 QSOs).Comment: Accepted for publication in ApJ. 57 pages with 13 figures, 9 JPG
plates, 5 additional PS tables. Original EPS plates (gzipped format
~1Mbyte/plate) and TeX tables are available from
ftp://ftp.kusastro.kyoto-u.ac.jp/pub/akiyama/0001289
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