Geometric phase as a determinant of a qubit--environment coupling

We investigate the qubit geometric phase and its properties in dependence on the mechanism for decoherence of a qubit weakly coupled to its environment. We consider two sources of decoherence: dephasing coupling (without exchange of energy with environment) and dissipative coupling (with exchange of energy). Reduced dynamics of the qubit is studied in terms of the rigorous Davies Markovian quantum master equation, both at zero and non--zero temperature. For pure dephasing coupling, the geometric phase varies monotonically with respect to the polar angle (in the Bloch sphere representation) parameterizing an initial state of the qubit. Moreover, it is antisymmetric about some points on the geometric phase-polar angle plane. This is in distinct contrast to the case of dissipative coupling for which the variation of the geometric phase with respect to the polar angle typically is non-monotonic, displaying local extrema and is not antisymmetric. Sensitivity of the geometric phase to details of the decoherence source can make it a tool for testing the nature of the qubit--environment interaction.Comment: accepted for publication in Quantum Information Processin

Non-adiabatic holonomic quantum computation

We develop a non-adiabatic generalization of holonomic quantum computation in which high-speed universal quantum gates can be realized by using non-Abelian geometric phases. We show how a set of non-adiabatic holonomic one- and two-qubit gates can be implemented by utilizing optical transitions in a generic three-level $\Lambda$ configuration. Our scheme opens up for universal holonomic quantum computation on qubits characterized by short coherence times.Comment: Some changes, journal reference adde

Realization of universal nonadiabatic geometric control on decoherence-free qubits in the XY model

A fundamental requirement of quantum information processing is the protection from the adverse effects of decoherence and noise. Decoherence-free subspaces and geometric processing are important steps of quantum information protection. Here, we provide a new experimentally feasible scheme to combine decoherence-free subspaces with nonadiabatic geometric manipulations to attain a universal quantum computation. The proposed scheme is different from previous proposals and is based on the typical XY interaction coupling, which can be set up in various nano-engineered systems and therefore open up for realization of nonadiabatic holonomic quantum computation in decoherence-free subspaces.Comment: 21 pages, 5 figure

On the stability of quantum holonomic gates

We provide a unified geometrical description for analyzing the stability of holonomic quantum gates in the presence of imprecise driving controls (parametric noise). We consider the situation in which these fluctuations do not affect the adiabatic evolution but can reduce the logical gate performance. Using the intrinsic geometric properties of the holonomic gates, we show under which conditions on noise's correlation time and strength, the fluctuations in the driving field cancel out. In this way, we provide theoretical support to previous numerical simulations. We also briefly comment on the error due to the mismatch between real and nominal time of the period of the driving fields and show that it can be reduced by suitably increasing the adiabatic time.Comment: 7 page

Simple, rapid and accurate molecular diagnosis of acute promyelocytic leukemia by loop mediated amplification technology

The diagnostic work-up of acute promyelocytic leukemia (APL) includes the cytogenetic demonstration of the t(15;17) translocation and/or the PML-RARA chimeric transcript by RQ-PCR or RT-PCR. This latter assays provide suitable results in 3-6 hours. We describe here two new, rapid and specific assays that detect PML-RARA transcripts, based on the RT-QLAMP (Reverse Transcription-Quenching Loop-mediated Isothermal Amplification) technology in which RNA retrotranscription and cDNA amplification are carried out in a single tube with one enzyme at one temperature, in fluorescence and real time format. A single tube triplex assay detects bcr1 and bcr3 PML-RARA transcripts along with GUS housekeeping gene. A single tube duplex assay detects bcr2 and GUSB. In 73 APL cases, these assays detected in 16 minutes bcr1, bcr2 and bcr3 transcripts. All 81 non-APL samples were negative by RT-QLAMP for chimeric transcripts whereas GUSB was detectable. In 11 APL patients in which RT-PCR yielded equivocal breakpoint type results, RT-QLAMP assays unequivocally and accurately defined the breakpoint type (as confirmed by sequencing). Furthermore, RT-QLAMP could amplify two bcr2 transcripts with particularly extended PML exon 6 deletions not amplified by RQ-PCR. RT-QLAMP reproducible sensitivity is 10(-3) for bcr1 and bcr3 and 10(-)2 for bcr2 thus making this assay particularly attractive at diagnosis and leaving RQ-PCR for the molecular monitoring of minimal residual disease during the follow up. In conclusion, PML-RARA RT-QLAMP compared to RT-PCR or RQ-PCR is a valid improvement to perform rapid, simple and accurate molecular diagnosis of APL

Biochemical and molecular characterization of two low-phytate pea lines

Phytate is the major storage form of phosphorus in crop seeds, but is not well digested by humans and non-ruminant animals. In addition, phytate chelates several essential micronutrients which are also excreted contributing to phosphorus pollution in the environment. This research was aimed at the biochemical and molecular characterization of two low phytate pea mutant lines, 1-150-81 and 1-2347-144 developed at the Crop Development Centre, University of Saskatchewan in collaboration with Dr. Victor Raboy, USDA, Idaho. Low phytic acid (lpa) crops are low in phytic acid and high in inorganic phosphorus (Pi). In Study I, two lpa pea genotypes, 1-150-81, 1-2347-144, and their progenitor CDC Bronco were evaluated in field trials for two years. The lpa genotypes did not significantly differ from CDC Bronco in all agronomic traits assessed except for lower seed weight and grain yield. The concentration of IP6 at 14 DAF was not significantly different among CDC Bronco, 1-150-81 and 1-2347-144. However, the concentrations of IP6 among CDC Bronco, 1-150-81 and 1-2347-144 started to differ significantly from 21 DAF onwards. The lpa genotypes 1-150-81 and 1-2347-144 showed 65% and 60% reduction in IP6, respectively, when compared to their progenitor CDC Bronco at 49 DAF. The Pi concentrations between the lpa genotypes were similar and significantly higher than CDC Bronco from 21 DAF to 49 DAF. At 49 DAF, 1-150-81 and 1-2347-144 were 72 and 84% higher in Pi, respectively, than CDC Bronco. The total P concentration was similar in lpa genotypes and CDC Bronco throughout the seed development. This study elucidated the rate and accumulation of phosphorus compounds in lpa genotypes. In Study II, aiming at understanding the genetic basis of the lpa mutation in pea lines 1-150-81 and 1-2347-144, a 1530 bp open reading frame of myo-inositol phosphate synthase gene (MIPS) was amplified from CDC Bronco and the lpa genotypes. Sequencing results showed no difference in coding sequence in MIPS between CDC Bronco and lpa genotypes. Transcript levels of both MIPS and myo-inositol tetrakisphosphate1-kinase (ITPK1) were relatively lower at 49 DAF than at 14 DAF for CDC Bronco and lpa lines. There was no difference in expression level of both MIPS and ITPK1 between CDC Bronco and the lpa genotypes at 49 DAF. The data demonstrated that mutation in MIPS was not responsible for lpa trait in pea. Study III was aimed at developing a single nucleotide polymorphism (SNP) based genetic linkage map and mapping genomic regions associated with phytic acid-phosphorus (PA-P) concentration using PR-15 recombinant inbred lines (RILs) derived from a cross between a low phytate (lpa) pea genotype, 1-2347-144 and normal phytate pea cultivar CDC Meadow. A total of 163 RILs were genotyped using 1536 SNP markers in an Illumina GoldenGate array. Three hundred and sixty seven polymorphic SNP markers, ordered into 7 linkage groups (LGs), generated a linkage map with a total length of 437.2 cM. The phytic acid locus was mapped on to LG5. A quantitative trait locus (QTL) for iron bioavailability was mapped on to the same location in LG5 as phytic acid concentration. Potential benefits arising out of this research include improved bioavailability of phosphorus, iron and zinc in foods and feeds, less phosphorus excretion and environmental pollution and a saving in feed costs

Análisis espectral de datos gravimétricos en el Complejo Volcánico La Yeguada

El estudio consiste en el análisis de datos gravimétricos obtenidos en el Complejo Volcánico La Yeguada, Provincia de Veraguas. Mediante el mismo, se establece la distribución de masas del subsuelo y una representación espacial de la capa geológica más profunda. Se aplicó la Doble Transformada de Fourier a los valores de gravedad observados, logrando obtener el espectro radial que permite fijar las frecuencias de corte para el diseño de los filtros digitales y así producir la separación de las anomalías de Bouguer en sus componentes regional y residual. Ambas componentes contienen información útil de las estructuras geológicas regional y local respectivamente, para su posterior interpretación cualitativa y cuantitativa. Igualmente, se aplicó la Doble Transformada de Fourier al mapa que contiene las anomalías de Bouguer regionales, y a partir de su espectro radial de frecuencia, se estimó la profundidad de los cuerpos geológicos

Entwicklung eines neuartigen Kartuschensystems zur automatisierten Probenvorbereitung bei der Quantifizierung von Pharmaka mittels Massenspektrometrie

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The human NPM1 mutation A perturbs megakaryopoiesis in a conditional mouse model.

The NPM1 mutation is the most frequent genetic alteration thus far identified in acute myeloid leukemia (AML). Despite progress in the clinical and biological characterization of NPM1-mutated AML, the role of NPM1 mutation in leukemogenesis in vivo has not been fully elucidated. We report a novel mouse model that conditionally expresses the most common human NPM1 mutation (type A) in the hematopoietic compartment. In Npm1-TCTG/WT;Cre+ mice, the NPM1 mutant localized in the cytoplasm (NPMc+) of bone marrow (BM) cells. The mutant mice developed no AML after 1.5-year follow-up. However, NPMc+ expression determined a significant platelet count reduction and an expansion of the megakaryocytic compartment in the BM and spleen. Serum thrombopoietin levels overlapped in mutant vs control mice, and BM cells from Npm1-TCTG/WT;Cre+ mice formed more megakaryocytic colonies in vitro. Moreover, we demonstrated the up-regulation of microRNAs (miRNAs; miR-10a, miR-10b, and miR-20a) inhibiting megakaryocytic differentiation along with increased expression of HOXB genes. Notably, these findings mimic those of human NPM1-mutated AML, which also exhibits a similar miRNA profile and expansion of the megakaryocytic compartment. Our mouse model provides evidence that the NPM1 mutant affects megakaryocytic development, further expanding our knowledge of the role of NPM1 mutant in leukemogenesis