4,138 research outputs found
A High Statistics Lattice Calculation of The B-meson Binding Energy
We present a high statistics lattice calculation of the B--meson binding
energy of the heavy--quark inside the pseudoscalar
B--meson. Our numerical results have been obtained from several independent
numerical simulations at , and , and using, for the meson
correlators, the results obtained by the APE group at the same values of
. Our best estimate, obtained by combining results at different values
of , is MeV. For the
running mass, we obtain
GeV, in reasonable
agreement with previous determinations. The systematic error is the truncation
of the perturbative series in the matching condition of the relevant operator
of the Heavy Quark Effective Theory.Comment: Latex, 13 pages, 1 figure appended in uuencoded gzip.tar.fil
Space physics analysis network node directory (The Yellow Pages): Fourth edition
The Space Physics Analysis Network (SPAN) is a component of the global DECnet Internet, which has over 17,000 host computers. The growth of SPAN from its implementation in 1981 to its present size of well over 2,500 registered SPAN host computers, has created a need for users to acquire timely information about the network through a central source. The SPAN Network Information Center (SPAN-NIC) an online facility managed by the National Space Science Data Center (NSSDC) was developed to meet this need for SPAN-wide information. The remote node descriptive information in this document is not currently contained in the SPAN-NIC database, but will be incorporated in the near future. Access to this information is also available to non-DECnet users over a variety of networks such as Telenet, the NASA Packet Switched System (NPSS), and the TCP/IP Internet. This publication serves as the Yellow Pages for SPAN node information. The document also provides key information concerning other computer networks connected to SPAN, nodes associated with each SPAN routing center, science discipline nodes, contacts for primary SPAN nodes, and SPAN reference information. A section on DECnet Internetworking discusses SPAN connections with other wide-area DECnet networks (many with thousands of nodes each). Another section lists node names and their disciplines, countries, and institutions in the SPAN Network Information Center Online Data Base System. All remote sites connected to US-SPAN and European-SPAN (E-SPAN) are indexed. Also provided is information on the SPAN tail circuits, i.e., those remote nodes connected directly to a SPAN routing center, which is the local point of contact for resolving SPAN-related problems. Reference material is included for those who wish to know more about SPAN. Because of the rapid growth of SPAN, the SPAN Yellow Pages is reissued periodically
Volume 12, Number 2- December 1931
Volume 12, Number 2 – December 1931. 32 pages including covers and advertisements. Who\u27s Who in the Alembic A Christmas Message from the Dean Harrison, George F. A Reply to \u27An Open Letter to a Freshman\u27 McDonald, Martin J. The Time Element Enters Lilly, Daniel The Egotist\u27s Soliloquy McDonough, John Stella Matutina Norback, Howard G. P.C. Personalities: Mickey Foster Hoban, Albert J. Release Shunny, Walter J. Chiaroscuro Considine, George L. A Transitional Painter Haylon, William D. The Checkerboard O\u27Neill, Matthew F. The Alumni Corner Tebbetts, George Athletic
Moments with Yakov Borisovich Zeldovich
A recollection of special moments spent with Yakov Borisovich Zeldovich and
with the scientists of Soviet Union and abroad.Comment: To appear in the proceedings of the international conference "The
Sun, the Stars, The Universe and General Relativity" in honor of Ya.B.
Zeldovich 95th Anniversary, held in Minsk, Belarus on April 20-23, 200
Rapid Assessment of Susceptibility of Bacteria and Erythrocytes to Antimicrobial Peptides by Single-Cell Impedance Cytometry
Antimicrobial peptides (AMPs) represent a promising classof compoundsto fight antibiotic-resistant infections. In most cases, they killbacteria by making their membrane permeable and therefore exhibitlow propensity to induce bacterial resistance. In addition, they areoften selective, killing bacteria at concentrations lower than thoseat which they are toxic to the host. However, clinical applicationsof AMPs are hindered by a limited understanding of their interactionswith bacteria and human cells. Standard susceptibility testing methodsare based on the analysis of the growth of a bacterial populationand therefore require several hours. Moreover, different assays arerequired to assess the toxicity to host cells. In this work, we proposethe use of microfluidic impedance cytometry to explore the actionof AMPs on both bacteria and host cells in a rapid manner and withsingle-cell resolution. Impedance measurements are particularly well-suitedto detect the effects of AMPs on bacteria, due to the fact that themechanism of action involves perturbation of the permeability of cellmembranes. We show that the electrical signatures of Bacillus megaterium cells and human red blood cells(RBCs) reflect the action of a representative antimicrobial peptide,DNS-PMAP23. In particular, the impedance phase at high frequency (e.g.,11 or 20 MHz) is a reliable label-free metric for monitoring DNS-PMAP23bactericidal activity and toxicity to RBCs. The impedance-based characterizationis validated by comparison with standard antibacterial activity assaysand absorbance-based hemolytic activity assays. Furthermore, we demonstratethe applicability of the technique to a mixed sample of B. megaterium cells and RBCs, which paves the wayto study AMP selectivity for bacterial versus eukaryotic cells inthe presence of both cell types
Analysis of Self-Organized Criticality in the Olami-Feder-Christensen model and in real earthquakes
We perform a new analysis on the dissipative Olami-Feder-Christensen model on
a small world topology considering avalanche size differences. We show that
when criticality appears the Probability Density Functions (PDFs) for the
avalanche size differences at different times have fat tails with a q-Gaussian
shape. This behaviour does not depend on the time interval adopted and is found
also when considering energy differences between real earthquakes. Such a
result can be analytically understood if the sizes (released energies) of the
avalanches (earthquakes) have no correlations. Our findings support the
hypothesis that a self-organized criticality mechanism with long-range
interactions is at the origin of seismic events and indicate that it is not
possible to predict the magnitude of the next earthquake knowing those of the
previous ones.Comment: 5 pages, 3 figures. New version accepted for publication on PRE Rapid
Communication
An annotated checklist and bibliography of the diaptomidae (copepoda, calanoida) of Italy, Corsica, and the maltese islands
Calanoids of the family Diaptomidae are the most widespread copepods in the lentic inland waters of the Palearctic region. In Italy, studies on the family date back to the end of 19th century. Since then, several papers contributed to increase the knowledge on their presence, distribution, and ecological preferences. Nevertheless, new records for the area and the discovery of putative new species stress that the current knowledge on these inland water crustaceans is still far from being exhaustive. This paper presents an updated and annotated checklist and bibliography of the Diaptomidae of the Italian peninsula and surrounding islands, including Corsica and the Maltese islands, compiled through a critical review of the existing literature and carrying out further field research. The doubtful records reported in the literature are discussed and clarified. The updated checklist includes 30 diaptomid species and subspecies; among them, an alien species and three putative new species pending formal description are reported. About 20% of the observed species are endemic or subendemic to the study area. The faunal provinces ascribed to the Mediterranean limnofaunistic region host the highest species richness and contribute to the checklist with rare species and unique occurrences. The high species richness observed in the Mediterranean area supports the hypothesis of a long-lasting persistence of an ancient and peculiar copepod fauna
A lattice study of the exclusive decay amplitude, using the Clover action at
We present the results of a numerical calculation of the
form factors. The results have been obtained by studying the relevant
correlation functions at , on an lattice, using the
-improved fermion action, in the quenched approximation. From the
study of the matrix element we have
obtained the form factor which controls the exclusive decay rate. The
results are compared with the recent results from CLEO. We also discuss the
compatibility between the scaling laws predicted by the Heavy Quark Effective
Theory (HQET) and pole dominance, by studying the mass- and -dependence of
the form factors. From our analysis, it appears that the form factors follow a
mass behaviour compatible with the predictions of the HQET and that the
-dependence of is weaker than would be predicted by pole dominance.Comment: 17 pages, LaTeX + epsf.sty. Uuencoded, compressed, tar archive
including the text and one postscript figur
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