Probing States in the Mott Insulator Regime

We propose a method to probe states in the Mott insulator regime produced from a condensate in an optical lattice. We consider a system in which we create time-dependent number fluctuations in a given site by turning off the atomic interactions and lowering the potential barriers on a nearly pure Mott state to allow the atoms to tunnel between sites. We calculate the expected interference pattern and number fluctuations from such a system and show that one can potentially observe a deviation from a pure Mott state. We also discuss a method in which to detect these number fluctuations using time-of-flight imaging.Comment: 4 pages, 3 figures. Send correspondence to [email protected]

Density modulations in an elongated Bose-Einstein condensate released from a disordered potential

We observe large density modulations in time-of-flight images of elongated Bose-Einstein condensates, initially confined in a harmonic trap and in the presence of weak disorder. The development of these modulations during the time-of-flight and their dependence with the disorder are investigated. We render an account of this effect using numerical and analytical calculations. We conclude that the observed large density modulations originate from the weak initial density modulations induced by the disorder, and not from initial phase fluctuations (thermal or quantum).Comment: Published version; 4+ pages; 4 figure

Plasmodium falciparum infection induces dynamic changes in the erythrocyte phospho-proteome

The phosphorylation status of red blood cell proteins is strongly altered during the infection by the malaria parasite Plasmodium falciparum. We identify the key phosphorylation events that occur in the erythrocyte membrane and cytoskeleton during infection, by a comparative analysis of global phospho-proteome screens between infected (obtained at schizont stage) and uninfected RBCs. The meta-analysis of reported mass spectrometry studies revealed a novel compendium of 495 phosphorylation sites in 182 human proteins with regulatory roles in red cell morphology and stability, with about 25% of these sites specific to infected cells. A phosphorylation motif analysis detected 7 unique motifs that were largely mapped to kinase consensus sequences of casein kinase II and of protein kinase A/protein kinase C. This analysis highlighted prominent roles for PKA/PKC involving 78 phosphorylation sites. We then compared the phosphorylation status of PKA (PKC) specific sites in adducin, dematin, Band 3 and GLUT-1 in uninfected RBC stimulated or not by cAMP to their phosphorylation status in iRBC. We showed cAMP-induced phosphorylation of adducin S59 by immunoblotting and we were able to demonstrate parasite-induced phosphorylation for adducin S726, Band 3 and GLUT-1, corroborating the protein phosphorylation status in our erythrocyte phosphorylation site compendium

The Complexity of Codiagnosability for Discrete Event and Timed Systems

In this paper we study the fault codiagnosis problem for discrete event systems given by finite automata (FA) and timed systems given by timed automata (TA). We provide a uniform characterization of codiagnosability for FA and TA which extends the necessary and sufficient condition that characterizes diagnosability. We also settle the complexity of the codiagnosability problems both for FA and TA and show that codiagnosability is PSPACE-complete in both cases. For FA this improves on the previously known bound (EXPTIME) and for TA it is a new result. Finally we address the codiagnosis problem for TA under bounded resources and show it is 2EXPTIME-complete.Comment: 24 pages

Tapered-amplified AR-coated laser diodes for Potassium and Rubidium atomic-physics experiments

We present a system of room-temperature extended-cavity grating-diode lasers (ECDL) for production of light in the range 760-790nm. The extension of the tuning range towards the blue is permitted by the weak feedback in the cavity: the diodes are anti-reflection coated, and the grating has just 10% reflectance. The light is then amplified using semiconductor tapered amplifiers to give more than 400mW of power. The outputs are shown to be suitable for atomic physics experiments with potassium (767nm), rubidium (780nm) or both, of particular relevance to doubly-degenerate boson-fermion mixtures

Learning affects host preference in tsetse flies

Les glossines sont des vecteurs cycliques très efficaces des trypanosomoses animales. Etant généralement infectées dès le premier repas de sang, en particulier dans le cas de la maladie du sommeil, toute tendance à retourner sur la première espèce hôte rencontrée se traduirait par une augmentation de la transmission intra-spécifique du parasite au détriment de sa transmission interspécifique. Pour tester cette hypothèse, un choix entre deux hôtes (vache et varan) a été proposé en étable sous moustiquaire à des glossines marquées (Glossina palpalis gambiensis, Diptera : Glossinidae) préalablement nourries sur un de ces deux hôtes. Quatre-vingts pourcent des glossines ténérales choisirent d’exploiter la vache lorsque le choix leur fut proposé. Parmi les glossines nourries une première fois sur un des deux hôtes, une proportion significativement supérieure de glossines sont retournées sur le premier hôte rencontré. Les avantages énergétiques et les implications épidémiologiques de ce comportement dans la transmission du parasite de la maladie du sommeil du réservoir animal à l’homme sont discutés. Enfin, la question de l’impact de l’apprentissage dans l’épidémiologie des zoonoses à transmission vectorielle est posée.Tsetse flies are very efficient cyclic vectors of African trypanosomosis. Since tsetse are generally infected by the first blood meal, as in the case of sleep-ing sickness for example, any propensity to feed on the same host a second time will improve transmission within this host species, whereas transmission between host species will decrease. To test this hypothesis we presented a monitor lizard and a cow in a stable to marked tsetse flies that had first fed on one of these two hosts. 80% of the teneral flies that fed did so on the cow when provided the choice. Among the flies having feeding experience, a dis-proportionately high number of flies that had fed on one host returned to this host for the second meal. We discuss the energetic advantages of such a learn-ing behavior and its importance in sleeping sickness epidemiology. The find-ings are of relevance to the role played by such learning behavior in disease transmission by other insect vectors of zoonoses.Las moscas tse-tse son vectores cíclicos muy eficientes de la tripanosomosis africana. En vista de que las tse-tse generalmente se infectan con su primera alimentación de sangre, como por ejemplo en el caso de la enfermedad del sueño, cualquier propensión a alimentarse una segunda vez en el mismo huésped mejora la transmisión al interior de las especies huéspedes mientras que la transmisión entre especies huéspedes disminuye. Para probar esta hipótesis, presentamos una lagartija monitor y una vaca en un establo, para marcar las moscas tse-tse que se alimentan por primera vez en uno de estos huéspedes. 80% de las moscas tenerales que se alimentaron, lo hicieron en la vaca cuando la escogencia les fue propuesta. Entre las moscas que experimentaron la alimentación, un número desproporcionado de moscas que se alimentaron en uno de los huéspedes volvieron a este huésped para su segunda comida. Discutimos las ventajas energéticas de este comportamiento aprendido y su importancia en la epidemiología de la enfermedad del sueño. Estos hallazgos son relevantes para el papel que juegan estos comportamientos aprendidos en la transmisión de la enfermedad por otros insectos vectores de zoonosis

Optimal infinite scheduling for multi-priced timed automata

This paper is concerned with the derivation of infinite schedules for timed automata that are in some sense optimal. To cover a wide class of optimality criteria we start out by introducing an extension of the (priced) timed automata model that includes both costs and rewards as separate modelling features. A precise definition is then given of what constitutes optimal infinite behaviours for this class of models. We subsequently show that the derivation of optimal non-terminating schedules for such double-priced timed automata is computable. This is done by a reduction of the problem to the determination of optimal mean-cycles in finite graphs with weighted edges. This reduction is obtained by introducing the so-called corner-point abstraction, a powerful abstraction technique of which we show that it preserves optimal schedules

Efficient engineering of multi-atom entanglement through single-photon detections

We propose an efficient scheme to engineer multi-atom entanglement by detecting cavity decay through single-photon detectors. In the special case of two atoms, this scheme is much more efficient than previous probabilistic schemes, and insensitive to randomness in the atom's position. More generally, the scheme can be used to prepare arbitrary superpositions of multi-atom Dicke states without the requirements of high-efficiency detection and separate addressing of different atoms.Comment: 5 pages, 2 figure