פרסומים

We consider the class of two-person zero-sum allocation games known as Captain Lotto games (Hart 2014). These are Colonel Blotto type games in which the players have capacity constraints. We show that the players optimal strategies are unique in most cases.

We report on the implementation of a high fidelity universal gate-set on optical qubits based on trapped 88Sr+ ions for the purpose of quantum information processing. All coherent operations were performed using a narrow linewidth diode laser. We employed a master-slave configuration for the laser, where an ultra low expansion glass Fabry–Perot cavity is used as a stable reference as well as a spectral filter. We characterized the laser spectrum using the ions with a modified Ramsey sequence which eliminated the affect of the magnetic field noise. We demonstrated high fidelity single qubit gates with individual addressing, based on inhomogeneous micromotion, on a two-ion chain as well as the Mølmer–Sørensen two-qubit entangling gate.

We propose a set of techniques that enable universal quantum computing to be carried out using dressed states. This applies in particular to the effort of realizing quantum computation in trapped ions using long-wavelength radiation, where coupling enhancement is achieved by means of static magnetic-field gradient. We show how the presence of dressing fields enables the construction of robust single and multi-qubit gates despite the unavoidable presence of magnetic noise, an approach that can be generalized to provide shielding in any analogous quantum system that relies on the coupling of electronic degrees of freedom via bosonic modes.

LETTER Here are some comments and useful suggestions after reading an article in mBio by Brown et al. entitled “Mechanisms underlying the exquisite sensitivity of Candida albicans to combinatorial cationic and oxidative stress that enhances the potent fungicidal activity of phagocytes” (1). In this paper, we are informed that a simultaneous exposure to 5 mM H2O2 and to cationic NaCl at 1 M is much more potent than the individual stresses themselves and that this combinatorial stress kills C. albicans synergistically in vitro. Such combinations are obviously absolutely unrealistic and not physiological. As a comparison I wonder why the authors had not also tested naturally occurring antimicrobial cationic peptides such as LL37 found in large amounts in neutrophil granules? Had the authors read the classical papers describing the possible mechanisms of bactericidal effects of neutrophils, they would have realized that there is actually no free-floating H2O2 in phagosomes following phagocytosis. This is because activation of NADPH-oxidase yields superoxide, which very rapidly interacts with myeloperoxidase (MPO) and with a halide (Cl-) to generate microbicidal amounts of hypochlorous acid (HOCl) (2–5)! Therefore, HOCl should have definitely been considered and tested in the system described by the authors. Also, the term flux used may be inappropriate since, in their study, both H2O2 and NaCl were actually applied as a bolus. Fluxes of oxidants are generated mainly by activated neutrophils and macrophages and by xanthine and xanthine oxidase in endothelial cells (2) Also, I wonder whether Na used is specific and whether potassium ions can also have the same effects in their system? The authors also claimed that catalase-derived peroxide detoxification, which is inhibited by cations, leads to intracellular ROS accumulation because catalase activity had been affected. If so, why had the catalase inhibitor azide or aminotriazole not been tested? In their study, the authors grew Candida cells in Tris-buffered yeast extract-peptone-dextrose medium (YPDT; pH 7.4). However, the authors have not cited key papers showing that D-glucose, in media on which candida grow, may also suppress catalase formation (6, 7). Using unrealistic, nonphysiological amounts of reagents will not increase our understanding of how biological processes really occur in vivo, despite the need to employ in vitro models. Also, disregarding key published data on neutrophil functions and Candida biology is unacceptable. Can this be a “menace to the future of honest science” (8) and also a “transgression” (9)? See also a recent publication by Casadevall and Fang (10).

This paper examines the role of participant-observers in process groups. In analysing the findings, I apply not only classics of psychotherapy and group theory, but also borrow concepts from Foucauldian theory in order to understand the delicate effect of observation. This research uses a full participation method, together with interviews and document analysis. Findings show that observations have both functional and normative effects. Participant-observers provide feedback to the group and the leader, but also judge their behaviour and regulate the group’s dynamics. In addition, observations have an effect on the observers themselves by providing another aspect of training, a therapeutic process, and a way to adopt social skills and norms.

Intensity–Duration–Frequency (IDF) curves are widely used in flood risk management because they provide an easy link between the characteristics of a rainfall event and the probability of its occurrence. Weather radars provide distributed rainfall estimates with high spatial and temporal resolutions and overcome the scarce representativeness of point-based rainfall for regions characterized by large gradients in rainfall climatology. This work explores the use of radar quantitative precipitation estimation (QPE) for the identification of IDF curves over a region with steep climatic transitions (Israel) using a unique radar data record (23yr) and combined physical and empirical adjustment of the radar data. IDF relationships were derived by fitting a generalized extreme value distribution to the annual maximum series for durations of 20min, 1h and 4h. Arid, semi-arid and Mediterranean climates were explored using 14 study cases. IDF curves derived from the study rain gauges were compared to those derived from radar and from nearby rain gauges characterized by similar climatology, taking into account the uncertainty linked with the fitting technique. Radar annual maxima and IDF curves were generally overestimated but in 70% of the cases (60% for a 100yr return period), they lay within the rain gauge IDF confidence intervals. Overestimation tended to increase with return period, and this effect was enhanced in arid climates. This was mainly associated with radar estimation uncertainty, even if other effects, such as rain gauge temporal resolution, cannot be neglected. Climatological classification remained meaningful for the analysis of rainfall extremes and radar was able to discern climatology from rainfall frequency analysis.

Although researchers often assume their participants are naive to experimental materials, this is not always the case. We investigated how prior exposure to a task affects subsequent experimental results. Participants in this study completed the same set of 12 experimental tasks at two points in time, first as a part of the Many Labs replication project and again a few days, a week, or a month later. Effect sizes were markedly lower in the second wave than in the first. The reduction was most pronounced when participants were assigned to a different condition in the second wave. We discuss the methodological implications of these findings.

Understanding enzyme catalysis and developing ability to control of it are two great challenges in biochemistry. A few successful examples of computational-based enzyme design have proved the fantastic potential of computational approaches in this field, however, relatively modest rate enhancements have been reported and the further development of complementary methods is still required. Herein we propose a conceptually simple scheme to identify the specific role that each residue plays in catalysis. The scheme is based on a breakdown of the total catalytic effect into contributions of individual protein residues, which are further decomposed into chemically interpretable components by using valence bond theory. The scheme is shown to shed light on the origin of catalysis in wild-type haloalkane dehalogenase (wt-DhlA) and its mutants. Furthermore, the understanding gained through our scheme is shown to have great potential in facilitating the selection of non-optimal sites for catalysis and suggesting effective mutations to enhance the enzymatic rate.

Linear peptides containing the sequence WKTSRTSHY were used as lead compounds to synthesize a novel peptidomimetic antagonist of $\alpha$2$\beta$1 integrin, with platelet aggregation-inhibiting activity, named Vipegitide. Vipegitide is a 13-amino acid, folded peptidomimetic molecule, containing two $\alpha$-aminoisobutyric acid residues at positions 6 and 8 and not stable in human serum. Substitution of glycine and tryptophan residues at positions 1 and 2, respectively, with a unit of two polyethylene glycol (PEG) molecules yielded peptidomimetic Vipegitide-PEG2, stable in human serum for over 3 hours. Vipegitide and Vipegitide-PEG2 showed high potency (7×10(-10) M and 1.5×10(-10) M, respectively) and intermediate efficacy (40% and 35%, respectively) as well as selectivity toward $\alpha$2 integrin in inhibition of adhesion of $\alpha$1/$\alpha$2 integrin overexpressing cells toward respective collagens. Interaction of both peptidomimetics with extracellular active domain of $\alpha$2 integrin was confirmed in cell-free binding assay with recombinant $\alpha$2 A-domain. Integrin $\alpha$2$\beta$1 receptor is found on the platelet membrane and triggers collagen-induced platelet aggregation. Vipegitide and Vipegitide-PEG2 inhibited $\alpha$2$\beta$1 integrin-mediated adhesion of human and murine platelets under the flow condition, by 50%. They efficiently blocked adenosine diphosphate- and collagen I-induced platelet aggregation in platelet rich plasma and whole human blood. Higher potency of Vipegitide than Vipegitide-PEG2 is consistent with results of computer modeling of the molecules in water. These peptidomimetic molecules were acutely tolerated in mice upon intravenous bolus injection of 50 mg/kg. These results underline the potency of Vipegitide and Vipegitide-PEG2 molecules as platelet aggregation-inhibiting drug lead compounds in antithrombotic therapy.

This paper tests the visa-led tourism hypothesis which contends that easing of visa restrictions increases international tourism. Israel acts as a natural laboratory in this case with clear before and after junctures in visa restrictions. We use panel data on tourism to Israel from 60 countries during 1994–2012. In contrast to previous work we take account of nonstationarity in the data and test for the effect of multilateral resistance on tourism. Partial waivers of visa restrictions are estimated to increase tourism by 48 % and complete waivers increase tourism by 118 %. Other results include the adverse effect of Israel’s security situation on tourism, the beneficial effect of real devaluation on tourism, and the fact that the elasticity of tourism to Israel with respect to tourism to all destinations is very small.