91 research outputs found
Recommended from our members
Post-test analysis of PIPER-ONE PO-IC-2 experiment by RELAP5/MOD3 codes
RELAP5/MOD3.1 was applied to the PO-IC-2 experiment performed in PIPER-ONE facility, which has been modified to reproduce typical isolation condenser thermal-hydraulic conditions. RELAP5 is a well known code widely used at the University of Pisa during the past seven years. RELAP5/MOD3.1 was the latest version of the code made available by the Idaho National Engineering Laboratory at the time of the reported study. PIPER-ONE is an experimental facility simulating a General Electric BWR-6 with volume and height scaling ratios of 1/2,200 and 1./1, respectively. In the frame of the present activity a once-through heat exchanger immersed in a pool of ambient temperature water, installed approximately 10 m above the core, was utilized to reproduce qualitatively the phenomenologies expected for the Isolation Condenser in the simplified BWR (SBWR). The PO-IC-2 experiment is the flood up of the PO-SD-8 and has been designed to solve some of the problems encountered in the analysis of the PO-SD-8 experiment. A very wide analysis is presented hereafter including the use of different code versions
Holomorphic Anomalies in Topological Field Theories
We study the stringy genus one partition function of SCFT's. It is
shown how to compute this using an anomaly in decoupling of BRST trivial states
from the partition function. A particular limit of this partition function
yields the partition function of topological theory coupled to topological
gravity. As an application we compute the number of holomorphic elliptic curves
over certain Calabi-Yau manifolds including the quintic threefold. This may be
viewed as the first application of mirror symmetry at the string quantum level.Comment: 32 pages. Appendix by S.Kat
Non-alcoholic fatty liver disease: a multicentre clinical study BY the Italian Association for the Study of the Liver
Superbrane Actions and Geometrical Approach
We review a generic structure of conventional (Nambu-Goto and
Dirac-Born-Infeld-like) worldvolume actions for the superbranes and show how it
is connected through a generalized action construction with a doubly
supersymmetric geometrical approach to the description of super-p-brane
dynamics as embedding world supersurfaces into target superspaces.Comment: Based on talks given by the authors at the Volkov Memorial Seminar
"Supersymmetry and Quantum field Theory" (Kharkov, January 5-7, 1997), LaTeX
file, 11 pages Misprints corrected, references adde
Generalized action principle and extrinsic geometry for N=1 superparticle
It is proposed the generalized action functional for N=1 superparticle in
D=3,4,6 and 10 space-time dimensions. The superfield geometric approach
equations describing superparticle motion in terms of extrinsic geometry of the
worldline superspace are obtained on the base of the generalized action. The
off-shell superdiffeomorphism invariance (in the rheonomic sense) of the
superparticle generalized action is proved. It was demonstrated that the half
of the fermionic and one bosonic (super)fields disappear from the generalized
action in the analytical basis. Superparticle interaction with Abelian gauge
theory is considered in the framework of this formulation. The geometric
approach equations describing superparticle motion in Abelian background are
obtained.Comment: 31 pages. Late
Lorentz harmonics and superfield action. D=10, N=1 superstring
We propose a new version of the superfield action for a closed D=10, N=1
superstring where the Lorentz harmonics are used as auxiliary superfields. The
incorporation of Lorentz harmonics into the superfield action makes possible to
obtain superfield constraints of the induced worldsheet supergravity as
equations of motion. Moreover, it becomes evident that a so-called 'Wess-Zumino
part' of the superfield action is basically a Lagrangian form of the
generalized action principle. We propose to use the second Noether theorem to
handle the essential terms in the transformation lows of hidden gauge
symmetries, which remove dynamical degrees of freedom from the Lagrange
multiplier superfield.Comment: 23 pages, latex, no figures. V.2, minor corrections, a reference
adde
Segregation of Fluorescent Membrane Lipids into Distinct Micrometric Domains: Evidence for Phase Compartmentation of Natural Lipids?
Background: We recently reported that sphingomyelin (SM) analogs substituted on the alkyl chain by various fluorophores (e.g. BODIPY) readily inserted at trace levels into the plasma membrane of living erythrocytes or CHO cells and spontaneously concentrated into micrometric domains. Despite sharing the same fluorescent ceramide backbone, BODIPY-SM domains segregated from similar domains labelled by BODIPY-D-e-lactosylceramide (D-e-LacCer) and depended on endogenous SM.
Methodology/Principal Findings. We show here that BODIPY-SM further differed from BODIPY-D-e-LacCer or -glucosylceramide (GlcCer) domains in temperature dependence, propensity to excimer formation, association with a glycosylphosphatidylinositol (GPI)-anchored fluorescent protein reporter, and lateral diffusion by FRAP, thus demonstrating different lipid phases and boundaries. Whereas BODIPY-D-e-LacCer behaved like BODIPY-GlcCer, its artificial stereoisomer, BODIPY-L-t-LacCer, behaved like BODIPY- and NBD-phosphatidylcholine (PC). Surprisingly, these two PC analogs also formed micrometric patches yet preferably at low temperature, did not show excimer, never associated with the GPI reporter and showed major restriction to lateral diffusion when photobleached in large fields. This functional comparison supported a three-phase micrometric compartmentation, of decreasing order: BODIPY-GSLs > -SM > -PC (or artificial L-t-LacCer). Co-existence of three segregated compartments was further supported by double labelling experiments and was confirmed by additive occupancy, up to ~70% cell surface coverage. Specific alterations of BODIPY-analogs domains by manipulation of corresponding endogenous sphingolipids suggested that distinct fluorescent lipid partition might reflect differential intrinsic propensity of endogenous membrane lipids to form large assemblies.
Conclusions/Significance. We conclude that fluorescent membrane lipids spontaneously concentrate into distinct micrometric assemblies. We hypothesize that these might reflect preexisting compartmentation of endogenous PM lipids into non-overlapping domains of differential order: GSLs > SM > PC, resulting into differential self-adhesion of the two former, with exclusion of the latter
An Integrated Framework for Predicting Long-Term Productivity of Pastures in the Kingdom of Saudi Arabia
Influence of bank concentration and institutions on capital structure: New international evidence
- …