37 research outputs found
Non-Abelian Berry connections for quantum computation
In the holonomic approach to quantum computation information is encoded in a
degenerate eigenspace of a parametric family of Hamiltonians and manipulated by
the associated holonomic gates. These are realized in terms of the non-abelian
Berry connection and are obtained by driving the control parameters along
adiabatic loops. We show how it is possible, for a specific model, to
explicitly determine the loops generating any desired logical gate, thus
producing a universal set of unitary transformations. In a multi-partite system
unitary transformations can be implemented efficiently by sequences of local
holonomic gates. Moreover a conceptual scheme for obtaining the required
Hamiltonian family, based on frequently repeated pulses, is discussed, together
with a possible process whereby the initial state can be prepared and the final
one can be measured.Comment: 5 pages, no figures, revtex, minor changes, version accepted by Phys.
Rev A (rapid comm.
Holonomic Quantum Computation
We show that the notion of generalized Berry phase i.e., non-abelian
holonomy, can be used for enabling quantum computation. The computational space
is realized by a -fold degenerate eigenspace of a family of Hamiltonians
parametrized by a manifold . The point of represents classical
configuration of control fields and, for multi-partite systems, couplings
between subsystem. Adiabatic loops in the control induce non trivial
unitary transformations on the computational space. For a generic system it is
shown that this mechanism allows for universal quantum computation by composing
a generic pair of loops in Comment: Presentation improved, accepted by Phys. Lett. A, 5 pages LaTeX, no
figure
Spin network setting of topological quantum computation
The spin network simulator model represents a bridge between (generalised)
circuit schemes for standard quantum computation and approaches based on
notions from Topological Quantum Field Theories (TQFTs). The key tool is
provided by the fiber space structure underlying the model which exhibits
combinatorial properties closely related to SU(2) state sum models, widely
employed in discretizing TQFTs and quantum gravity in low spacetime dimensions.Comment: Proc. "Foundations of Quantum Information", Camerino (Italy), 16-19
April 2004, to be published in Int. J. of Quantum Informatio
Erosi贸n por contracci贸n y por estribo en puentes aliviadores en valle de inundaci贸n
En el presente trabajo se analiza, en forma experimental, la interrelaci贸n existente entre los distintos tipos de erosi贸n que se producen en puentes aliviadores, y sus vinculaciones con los par谩metros caracter铆sticos del escurrimiento. A tales fines se llev贸 a cabo una secuencia de ensayos de laboratorio, destinados especialmente a evaluar las modificaciones que sufre la distribuci贸n de caudales como consecuencia del desarrollo de la erosi贸n por estribo, y la incidencia que ello tiene sobre la erosi贸n por contracci贸n. Los resultados alcanzados demuestran que la reducci贸n del porcentaje de caudal, en la zona no afectada por la hoya de erosi贸n local, es funci贸n de la profundidad de socavaci贸n debida a la presencia del estribo. Sobre esta base se propone una secuencia de c谩lculo de las erosiones totales en un puente aliviador en valle de inundaci贸n, la cual reproduce adecuadamente valores medidos en prototipo durante la ocurrencia de una crecida extraordinaria
Spin network quantum simulator
We propose a general setting for a universal representation of the quantum
structure on which quantum information stands, whose dynamical evolution
(information manipulation) is based on angular momentum recoupling theory. Such
scheme complies with the notion of 'quantum simulator' in the sense of
Feynmann, and is shown to be related with the topological quantum field theory
approach to quantum computation.Comment: revtex, 6 pages + 5 figure
Erosi贸n por contracci贸n y por estribo en puentes aliviadores en valle de inundaci贸n
[ES] En el presente trabajo se analiza, en forma experimental, la interrelaci贸n existente entre los distintos tipos de erosi贸n que se producen en puentes aliviadores, y sus vinculaciones con los par谩metros caracter铆sticos del escurrimiento. A tales fines se llev贸 a cabo una secuencia de ensayos de laboratorio, destinados especialmente a evaluar las modificaciones que sufre la distribuci贸n de caudales como consecuencia del desarrollo de la erosi贸n por estribo, y la incidencia que ello tiene sobre la erosi贸n por contracci贸n. Los resultados alcanzados demuestran que la reducci贸n del porcentaje de caudal, en la zona no afectada por la hoya de erosi贸n local, es funci贸n de la profundidad de socavaci贸n debida a la presencia del estribo. Sobre esta base se propone una secuencia de c谩lculo de las erosiones totales en un puente aliviador en valle de inundaci贸n, la cual reproduce adecuadamente valores medidos en prototipo durante la ocurrencia de una crecida extraordinaria.A la Universidad Nacional del Litoral quien financi贸, por medio de los Cursos de Acci贸n para la Investigaci贸n y Desarrollo (CAI+D), el Proyecto de Investigaci贸n en el marco del cual se desarroll贸 este trabajo. Al Ingeniero Mario L. Amsler, por su revisi贸n cr铆tica del manuscrito original.Schreider, M.; Zanardi, L.; Scacchi, G.; Franco, F. (1998). Erosi贸n por contracci贸n y por estribo en puentes aliviadores en valle de inundaci贸n. Ingenier铆a del Agua. 5(2):23-34. https://doi.org/10.4995/ia.1998.2747SWORD233452Blench, T., (1969) Mobile-bed fluviology. University of Alberta Press, Canada, 168 p.Chow, V.T., (1959) Open Channel Hydraulic. McGraw-Hill Book Company, New York, 680 p.Dongol, D. M. S., (1994) Local scour at bridge abutment. Report N掳 544, Department of Civil Engineering, University of Auckland, Auckland, 410 p.Juarez Badillo, E. y Rico Rodriguez, A., (1984) Mec谩nica de Suelos. Tomo III, Flujo de Agua en Suelos, Editorial Limusa, 414 p.Kandasamy, J.K., (1989) Abutment scour, School of Engineering Report N掳 458, University of Auckland, Auckland, 278 p.Laursen, E. M., (1960) Scour at bridge crossings, Proceedings ASCE 86 (HY 2). pp. 39 - 54.Laursen, E. M., (1963) Analysis of relief bridges scour, ASCE, Journal of the Hydraulics Division, vol. 89, HY 3, pp. 93-118.Molinas, A., (1994) Bridge stream tube model for alluvial river simulation (BRISTARS). User Manual. National Cooperative Highway Research Program, Project N掳 HR15-11A, Transportation Research Board, Washington, D.C., 82 p.Prendes, H., Amsler, M.L., Schreider, M.I., Huespe, J.,Cian, C. y Lima, D., (1992) Metodolog铆a para calcular el volumen sedimentado en un paso de navegaci贸n, Anales de XV Congreso Latinoamericano de Hidr谩ulica. Cartagena, Vol. 3, pp. 195-205.Richardson, E.V., Simons, D.B. y Julien, P., (1990) Highwayin the river enviroment. FHWA-HI -90-016, Federal Highway Administration, U.S. Department of Transportation, Washington, D.C. 549 p.Schreider, M., Zanardi, L., Scacchi, G. y Franco, F., (1996) Interacci贸n entre la erosi贸n por contracci贸n y por estribo en puentes aliviadores en valle de inundaci贸n - Estudio experimental, Anales del XVII Congreso Latinoamericano de Hidr谩ulica. Guayaquil, Vol 4, pp. 363 - 374.Shearman, J.O., (1987) Bridge waterways analysis model for mainframe and microcomputers. WSPRO/ HY-7, Federal Highway Administration,U.S. Department of Transportation, Washington, D.C., 177 p. U.S. Department of Transportation, (1993) Hydraulic Engineering Circular, N掳 18, Evaluating scour at bridges. 2掳 Edition. Report N掳 FHWA-IP-90-017, Federal Highway Administration, Washington, D.C. 132 p
Short communication: Characterization of Staphylococcus aureus from bulk tank milk of dairy cattle in Lombardy (northern Italy).
ABSTRACT Staphylococcus aureus is one of the most important pathogens causing mastitis in cattle, and it is responsible for economic losses in dairy herds worldwide. The PCR amplification of the 16S-23S rRNA intergenic spacer (ribosomal spacer PCR, RS-PCR) allows a rapid classification of the strains in genotypes and genotypic clusters (CL), which are characterized by different epidemiological and clinical properties. Both RS-PCR and multi-locus sequence typing (MLST) were performed on strains isolated from bovine bulk tank milk (BTM) collected from dairy herds located in the Lombardy region (northern Italy), to outline the distribution of Staph. aureus genotypes in this geographical area. Out of 844 examined samples, 398 were positive for Staph. aureus, with a variable count (cfu/mL) Up to 8 colonies from each sample were genotyped. A total of 1,101 Staph. aureus strains were analyzed with RS-PCR, and only a selection of them (n = 86), in relation to their frequency and geographical origin, underwent MLST. This study revealed 8 major genotypic clusters (CLB, CLC, CLR, CLS, CLI, CLF, CLAO, and CLZ), of which Staph. aureus CLB (29.3%) was the most common. Samples of BTM positive for CLB had a Staph. aureus cfu/mL count significantly higher than the non-CLB positive ones. Our MLST analysis showed genotypes already known as bovine-associated in literature, such as clonal complexes CC8, CC97, and CC151. The same selection of 86 strains was also analyzed for the presence of the adlb gene, which was recently proposed as a possible marker of contagiousness. Most Staph. aureus belonging to CLB or CC8 carried the adlb gene (85%), whereas this gene was detected in only 9% of non-CLB strains (CLAA, CLBI, CLBJ, CLS). In conclusion, the present study confirms that Staph. aureus CLB, which is recognized as a contagious genotype, is a particularly relevant agent of intramammary infection in dairy cows in Lombardy, and indirectly supports the idea that adlb can be a possible marker of contagiousness of isolates
Storiografia filosofica e storiografia religiosa. Due punti di vista a confronto. Scritti in onore di Luciano Malusa
Il volume raccoglie una trentina di contributi sul tema della storiografia filosofica nel suo rapporto con la storiografia religiosa
A Spatially Resolved Dark- versus Light-Zone Microenvironment Signature Subdivides Germinal Center-Related Aggressive B Cell Lymphomas
We applied digital spatial profiling for 87 immune and stromal genes to lymph node germinal center (GC) dark- and light-zone (DZ/LZ) regions of interest to obtain a differential signature of these two distinct microenvironments. The spatially resolved 53-genes signature, comprising key genes of the DZmutational machinery and LZ immune and mesenchymal milieu, was applied to the transcriptomes of 543 GC-related diffuse large B cell lymphomas and double-hit ( DH) lymphomas. According to the DZ/LZ signature, the GC-related lymphomas were sub-classified into two clusters. The subgroups differed in the distribution of DH cases and survival, with most DH displaying a distinct DZ-like profile. The clustering analysis was also performed using a 25-genes signature composed of genes positively enriched in the non-B, stromal sub-compartments, for the first time achieving DZ/LZ discrimination based on stromal/immune features. The report offers new insight into the GC microenvironment, hinting at a DZ microenvironment of origin in DH lymphomas