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 $n$-fold degenerate eigenspace of a family of Hamiltonians parametrized by a manifold $\cal M$. The point of $\cal M$ represents classical configuration of control fields and, for multi-partite systems, couplings between subsystem. Adiabatic loops in the control $\cal M$ 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 $\cal M.$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

Erosión por contracción y por estribo en puentes aliviadores en valle de inundación

En el presente trabajo se analiza, en forma experimental, la interrelación existente entre los distintos tipos de erosión que se producen en puentes aliviadores, y sus vinculaciones con los parámetros característicos del escurrimiento. A tales fines se llevó a cabo una secuencia de ensayos de laboratorio, destinados especialmente a evaluar las modificaciones que sufre la distribución de caudales como consecuencia del desarrollo de la erosión por estribo, y la incidencia que ello tiene sobre la erosión por contracción. Los resultados alcanzados demuestran que la reducción del porcentaje de caudal, en la zona no afectada por la hoya de erosión local, es función de la profundidad de socavación debida a la presencia del estribo. Sobre esta base se propone una secuencia de cálculo de las erosiones totales en un puente aliviador en valle de inundación, 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

Erosión por contracción y por estribo en puentes aliviadores en valle de inundación

[ES] En el presente trabajo se analiza, en forma experimental, la interrelación existente entre los distintos tipos de erosión que se producen en puentes aliviadores, y sus vinculaciones con los parámetros característicos del escurrimiento. A tales fines se llevó a cabo una secuencia de ensayos de laboratorio, destinados especialmente a evaluar las modificaciones que sufre la distribución de caudales como consecuencia del desarrollo de la erosión por estribo, y la incidencia que ello tiene sobre la erosión por contracción. Los resultados alcanzados demuestran que la reducción del porcentaje de caudal, en la zona no afectada por la hoya de erosión local, es función de la profundidad de socavación debida a la presencia del estribo. Sobre esta base se propone una secuencia de cálculo de las erosiones totales en un puente aliviador en valle de inundación, la cual reproduce adecuadamente valores medidos en prototipo durante la ocurrencia de una crecida extraordinaria.A la Universidad Nacional del Litoral quien financió, por medio de los Cursos de Acción para la Investigación y Desarrollo (CAI+D), el Proyecto de Investigación en el marco del cual se desarrolló este trabajo. Al Ingeniero Mario L. Amsler, por su revisión crítica del manuscrito original.Schreider, M.; Zanardi, L.; Scacchi, G.; Franco, F. (1998). Erosión por contracción y por estribo en puentes aliviadores en valle de inundación. Ingeniería 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° 544, Department of Civil Engineering, University of Auckland, Auckland, 410 p.Juarez Badillo, E. y Rico Rodriguez, A., (1984) Mecánica de Suelos. Tomo III, Flujo de Agua en Suelos, Editorial Limusa, 414 p.Kandasamy, J.K., (1989) Abutment scour, School of Engineering Report N° 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° 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) Metodología para calcular el volumen sedimentado en un paso de navegación, Anales de XV Congreso Latinoamericano de Hidráulica. 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) Interacción entre la erosión por contracción y por estribo en puentes aliviadores en valle de inundación - Estudio experimental, Anales del XVII Congreso Latinoamericano de Hidráulica. 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° 18, Evaluating scour at bridges. 2° Edition. Report N° 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