Analyzing market competition between Airbus and Boeing using a duo hierarchical graph model for conflict resolution

A duo hierarchical graph model for conflict resolution is developed to investigate market competition between Airbus and Boeing over aircraft sales in the Asia Pacific region. The duo hierarchical graph model, a significant extension of the graph model for conflict resolution methodology, contains two common decision makers, who take part in two related subconflicts, as well as local decision makers, who participate in only one subconflict. New stability definitions are proposed to describe forms of sanction unique to the hierarchical model. The interrelationships between stabilities in the overall graph model and in the two local models are investigated. Then the duo hierarchical graph model is applied to the competition between Airbus and Boeing in both the wide and narrow body markets in the Asia-Pacific region. The two types of Asian airlines have different operating strategies, so that the two markets constitute sub-competitions that can be modelled naturally using the duo hierarchical graph model. The stability results indicate a resolution for all decision makers that implies marketing strategies for the aircraft manufacturers and guidelines for aircraft purchase by the airlines. Thus, this model provides decision makers with a comprehensive understanding of the dynamics of the competition and guidance in identifying beneficial actions.     

Ca2+ release-activated Ca2+ (CRAC) current, structure, and function

Store-operated Ca²⁺ entry describes the phenomenon that connects a depletion of internal Ca²⁺ stores to an activation of plasma membrane-located Ca²⁺ selective ion channels. Tremendous progress towards the underlying molecular mechanism came with the discovery of the two respective limiting components, STIM and Orai. STIM1 represents the ER-located Ca²⁺ sensor and transmits the signal of store depletion to the plasma membrane. Here it couples to and activates Orai, the highly Ca²⁺-selective pore-forming subunit of Ca²⁺ release-activated Ca²⁺ channels. In this review, we focus on the molecular steps that these two proteins undergo from store-depletion to their coupling, the activation, and regulation of Ca²⁺ currents.     

Enantioselective silyl protection of alcohols catalysed by an amino-acid-based small molecule

Reliable, selective and environmentally friendly chemical transformations are crucial to the development of new therapeutics and the design of novel materials. Chiral catalysts that can be easily prepared and used to obtain organic molecules of high enantiomeric purity are critical to modern chemical synthesis. The development of protecting groups that shield reactive functionalities has also proved indispensable in the preparation of complex biologically active molecules. Here we present a chiral catalyst that promotes the enantioselective protection of a secondary alcohol as one of the most commonly used protected forms of an alcohol: a silyl ether. The catalyst is a small, simple molecule that can be prepared in three steps from commercial materials without the need for rigorously controlled conditions. Enantioselective silylations are performed with commercial silyl chlorides and produce yields of up to 96 per cent at an enantiomeric ratio of up to 98:2. Chiral catalysts for selective formation of commonly used protecting groups such as silyl ethers should significantly enhance the ability of chemical synthesis to deliver, in a more practical and efficient manner, important organic molecules.     

Catestatin, an endogenous Chromogranin A-derived peptide, inhibits in vitro growth of Plasmodium falciparum

Catestatin, an endogenous peptide derived from bovine chromogranin A, and its active domain cateslytin display powerful antimicrobial activities. We have tested the activities of catestatin and other related peptides on the growth of Plasmodium falciparum in vitro. Catestatin inhibits growth of the chloroquine-sensitive strain of P. falciparum 3D7, exhibiting 88% inhibition at 20 μM. A similar partial inhibition of parasite growth was observed for the chloroquine-resistant strain, 7G8 (64%,) and the multidrug-resistant strain, W2 (62%). In the presence of parasite-specific lactate dehydrogenase, a specific protein–protein interaction between catestatin and plasmepsin II precursor was demonstrated. In addition, catestatin partially inhibited the parasite-specific proteases plasmepsin in vitro. A specific interaction between catestatin and plasmepsins II and IV from P. falciparum and plasmepsin IV from the three remaining species of Plasmodium known to infect man was observed, suggesting a catestatin-induced reduction in availability of nutrients for protein synthesis in the parasite.     

Single-spin addressing in an atomic Mott insulator

Ultracold atoms in optical lattices provide a versatile tool with which to investigate fundamental properties of quantum many-body systems. In particular, the high degree of control of experimental parameters has allowed the study of many interesting phenomena, such as quantum phase transitions and quantum spin dynamics. Here we demonstrate how such control can be implemented at the most fundamental level of a single spin at a specific site of an optical lattice. Using a tightly focused laser beam together with a microwave field, we were able to flip the spin of individual atoms in a Mott insulator with sub-diffraction-limited resolution, well below the lattice spacing. The Mott insulator provided us with a large two-dimensional array of perfectly arranged atoms, in which we created arbitrary spin patterns by sequentially addressing selected lattice sites after freezing out the atom distribution. We directly monitored the tunnelling quantum dynamics of single atoms in the lattice prepared along a single line, and observed that our addressing scheme leaves the atoms in the motional ground state. The results should enable studies of entropy transport and the quantum dynamics of spin impurities, the implementation of novel cooling schemes, and the engineering of quantum many-body phases and various quantum information processing applications.     

Single mimivirus particles intercepted and imaged with an X-ray laser

X-ray lasers offer new capabilities in understanding the structure of biological systems, complex materials and matter under extreme conditions. Very short and extremely bright, coherent X-ray pulses can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus or a cell before the sample explodes and turns into plasma. The continuous diffraction pattern of non-crystalline objects permits oversampling and direct phase retrieval. Here we show that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source. Calculations indicate that the energy deposited into the virus by the pulse heated the particle to over 100,000?K after the pulse had left the sample. The reconstructed exit wavefront (image) yielded 32-nm full-period resolution in a single exposure and showed no measurable damage. The reconstruction indicates inhomogeneous arrangement of dense material inside the virion. We expect that significantly higher resolutions will be achieved in such experiments with shorter and brighter photon pulses focused to a smaller area. The resolution in such experiments can be further extended for samples available in multiple identical copies.     

Dispersal characteristics of the yucca weevil ( Scyphophorus yuccae ) in a flowering field of Yucca whipplei

Dispersal characteristics were measured for a population of yucca weevils ( Scyphophorus yuccae ) in a plot consisting of flowering and nonflowering Yucca whipplei . We compared weevil dispersal to yucca distribution, pheonolgy, and caudex temperature. We also compared weevil movement to wind patterns and time of day. Captured weevils were marked and released into both flowering and nonflowering home plants in the field. Distance traveled, weevil flight direction, and target plant characteristics were recorded. We found that yucca weevils moved only between 1600 h on the release day and 0600 h of the following day. We recorded movement from both nonflowering and old flowering (> 1/2 stalk had reached anthesis) yuccas to new flowering (> 1/2 stalk pre-anthesis) yuccas. The pattern of weevil movement did not match the pattern of flowering yuccas in the field. Yucca weevils moved a mean distance of 33 ± 8 m. Caudex temperature appeared to be important to maintain a population of weevils on a plant. Wind direction was the best predictor of weevil dispersal direction. Weevils consistently moved into the wind, suggesting that they are active fliers. Dispersal characteristics of the yucca weevil have implications for the evolution of the semelparous flowering strategy of Y. whipplei and S. yuccae life history.     

Post-breeding season movements of Columbia spotted frogs ( Rana luteiventris ) in northeastern Oregon

Movements of Columbia spotted frogs ( Rana luteiventris ) were determined after breeding to provide managers with information on habitat requirements. We radio-tagged 47 adults and observed movements occurring with 22 frogs. Eleven frogs remained in breeding ponds, and 11 moved to other ponds or river stretches during spring and summer 1998. Distances frogs traveled to other water bodies ranged from 15 to 560 m. Movements appeared to be influenced by availability of habitat and aquatic conditions. Eleven of 16 frogs located within 100 m of other permanent water sources moved, while no frogs at an isolated breeding pond moved. Frogs moved to river stretches in July where water temperatures averaged 5.6 ° C cooler than ponds. Knowledge of Columbia spotted frog movements and habitat use in summer enables land managers to make decisions on activities that affect aquatic sites, vegetation, and stream structures that may influence frog populations.