Quantum multimode model of elastic scattering from Bose Einstein condensates

Mean field approximation treats only coherent aspects of the evolution of a Bose Einstein condensate. However, in many experiments some atoms scatter out of the condensate. We study an analytic model of two counter-propagating atomic Gaussian wavepackets incorporating dynamics of incoherent scattering processes. Within the model we can treat processes of elastic collision of atoms into the initially empty modes, and observe how, with growing occupation, the bosonic enhancement is slowly kicking in. A condition for bosonic enhancement effect is found in terms of relevant parameters. Scattered atoms form a squeezed state that can be viewed as a multi-component condensate. Not only are we able to calculate the dynamics of mode occupation, but also the full statistics of scattered atoms.Comment: 4 pages, 4 figure

On gene dosage balance in protein complexes: a comment on Semple JI, Vavouri T, Lehner B. A simple principle concerning the robustness of protein complex activity to changes in gene expression.

A comment on Semple JI, Vavouri T, Lehner B. A simple principle concerning the robustness of protein complex activity to changes in gene expression. BMC Syst Biol. 2008;2:

Compressed sensing quantum process tomography for superconducting quantum gates

We apply the method of compressed sensing (CS) quantum process tomography (QPT) to characterize quantum gates based on superconducting Xmon and phase qubits. Using experimental data for a two-qubit controlled-Z gate, we obtain an estimate for the process matrix $\chi$ with reasonably high fidelity compared to full QPT, but using a significantly reduced set of initial states and measurement configurations. We show that the CS method still works when the amount of used data is so small that the standard QPT would have an underdetermined system of equations. We also apply the CS method to the analysis of the three-qubit Toffoli gate with numerically added noise, and similarly show that the method works well for a substantially reduced set of data. For the CS calculations we use two different bases in which the process matrix $\chi$ is approximately sparse, and show that the resulting estimates of the process matrices match each ther with reasonably high fidelity. For both two-qubit and three-qubit gates, we characterize the quantum process by not only its process matrix and fidelity, but also by the corresponding standard deviation, defined via variation of the state fidelity for different initial states.Comment: 16 pages, 11 figure

Proteolysis of microtubule associated protein 2 and sensitivity of pancreatic tumours to docetaxel

We have studied the state of microtubule associated protein 2 (MAP2) in the pancreatic ductal adenocarcinomas P03 and P02 (sensitive and refractory to docetaxel respectively) since they express the corresponding mRNA and MAP2-related peptides. Immunohistochemical localization showed that in tumour P03 the MAP2-related peptides are highly expressed and confined to the epithelial malignant cells while in P02 the intensity of the immunostaining is lower. However, anti α-tubulin staining followed a similar pattern suggesting that the net amount of macromolecular structures in the sensitive tumour is higher than in the refractory one. This may explain its higher sensitivity to docetaxel, because tubulin assembled into microtubules is the target of the drug. We found that protein extracts from both tumours differed in their proteolytic activity on rat brain MAP2. Since the proteolysis pattern obtained was similar to the one produced by Cathepsin D, we studied the effect of MAP2 proteolysed by this enzyme on microtubule formation in vitro. Proteolysis was found to increase the tendency of tubulin to assemble into macromolecular structures (microtubules and aggregates) in the presence of docetaxel. This suggests that in vivo proteolysis of MAP2 might increase microtubule alterations and potentiate the antitumour effect of docetaxel. © 2000 Cancer Research Campaig

Rolling quantum dice with a superconducting qubit

One of the key challenges in quantum information is coherently manipulating the quantum state. However, it is an outstanding question whether control can be realized with low error. Only gates from the Clifford group -- containing $\pi$, $\pi/2$, and Hadamard gates -- have been characterized with high accuracy. Here, we show how the Platonic solids enable implementing and characterizing larger gate sets. We find that all gates can be implemented with low error. The results fundamentally imply arbitrary manipulation of the quantum state can be realized with high precision, providing new practical possibilities for designing efficient quantum algorithms.Comment: 8 pages, 4 figures, including supplementary materia

Efecto del filtrado de cultivo de Pseudocercospora fijiensis Morelet sobre yemas adventicias de cultivares de Musa spp.

The obtaining of bananas tolerant or resistant to the Black Sigatoka (Mycosphaerella fijiensis Morelet) is an imperious need since 1991 with its apparition in our country. The effect of the culture filtrate was studied on different strain of the fungus on adventitious buds of the cultivar Grande Naine (AAA) (susceptible) and Pellipita (ABB) (resistant) with the objective of determining possible differences between these cultivars the most effective strain and the optimum dilution. Adventitious buds of these cultivars formed in a cultivation medium with high concentrations of 6 BAP were utilized and then they were subcultivated on the selective medium that contained different dilutions of culture filtrate of the strains C-27, C-21, and C-19. It was evaluated at 15 and 30 days the fresh weight increment of the explants and the percentage of growth and mortality, being found differences between the susceptible cultivar and the resistant one with the most concentrated dilutions. The best results of differentiation were obtained with the dilution 1:5 The strains studied showed different effects on the explants. Significant differences were founded when C-21 and C-19 were used, not been so with the C-27. Growth stimulation was observed in both cultivars in the control treatment that contained the components of the fungus culture medium, discarding so any type of toxicity of these substances on the adventitious buds that could disguise the results.key words: Black Sigatoka, in vitro selection, Mycosphaerella fijiensis Morelet, strains, tissue cultureLa obtención de bananos tolerantes o resistentes a la Sigatoka Negra es una imperiosa necesidad a partir de su aparición en Cuba. Por ello se estudió el efecto del filtrado de cultivo de diferentes cepas del hongo sobre yemas adventicias de los cultivares Gran Enano (AAA) (susceptible) y Pellipita (ABB) (resistente) con el objetivo de determinar posibles diferencias entre los mismos, así como obtener la cepa más efectiva y la dilución óptima. Se utilizaron yemas adventicias de estos cultivares formadas en un medio de cultivo con altas concentraciones de 6 BAP y luego se subcultivaron al medio de cultivo selectivo, que contenía diferentes diluciones del filtrado de cultivo de las cepas C-27, C-21, y C-19. Se evaluó a los 15 y 30 días el incremento del peso fresco de los explantes y el porcentaje de crecimiento y mortalidad, encontrándose diferencias entre el cultivar susceptible y el resistente con las diluciones más concentradas. Los mejores resultados de diferenciación se obtuvieron con la dilución 1:5 (v/v). Las cepas estudiadas mostraron distintos efectos sobre los explantes. Se encontraron diferencias significativas cuando se utilizaron las cepas C-19 y C-21, no siendo así con la C-27. Se observó una estimulación del crecimiento de los explantes de ambos cultivares en el tratamiento control que contenía los componentes del medio de cultivo del hongo, descartándose así la posibilidad de cualquier tipo de toxicidad de estas sustancias sobre las yemas adventicias que pudieran enmascarar los resultados.Palabras clave: cepas, cultivo de tejidos, Mycosphaerella fijiensis Morelet, selección in vitro, Sigatoka negr

Diferenciación de la respuesta in vitro de Phaseolus vulgaris cv. ‘ICA Pijao’ y cv. ‘Tío Canela- 75’ a altas temperaturas

 To develop an in vitro selection protocol, it is necessary to differentiate between tolerant and susceptible cultivars to the studied factor. The present work was carried out with the objective of selecting the temperature that allows to in vitro differentiating the response of the Phaseolus vulgaris cultivars 'ICA Pijao' (susceptible) and 'Tío Canela-75' (tolerant) to high temperatures. Different temperatures (30, 35, 40, 45 and 50 ºC) were applied to seeds of the two cultivars. In vitro seed germination percentage, radicle and plumule length, number of explants that formed callus and number of shoots per callus were evaluated. It was possible to differentiate between cv. ‘ICA Pijao’ (susceptible) and ‘Tío Canela- 75’ (tolerant) with the variables radicle length, plumule length, percentage of calli formed and number of regenerated shoots. It was selected 35 °C as the selective agent.Para desarrollar un protocolo de selección in vitro se hace necesario lograr la diferenciación entre cultivares tolerantes y susceptibles al factor estudiado. El presente trabajo se realizó con el objetivo de seleccionar la temperatura que permita diferenciar in vitro la respuesta de los cultivares de Phaseolus vulgaris ‘ICA Pijao’ (susceptible) y ‘Tío Canela- 75’  (tolerante) a altas temperaturas. Se aplicaron diferentes temperatura (30, 35, 40, 45 y 50 ºC) a semillas de los  dos cultivares. Se evaluó in vitro, el porcentaje de germinación de las semillas, longitud de la radícula y la plúmula, número de explantes que formaron callos y número de brotes por callo.  Se logró diferenciar entre el cv. ‘ICA Pijao’ (susceptible) y ‘Tío Canela- 75’ (Tolerante) con las variables longitud de la radícula, longitud de la plúmula, porcentaje de callos formados y número de brotes regenerados.  Se seleccionó 35 ºC como agente selectivo