3,091 research outputs found

    Toward a systems understanding of plant–microbe interactions

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    Plants are closely associated with microorganisms including pathogens and mutualists that influence plant fitness. Molecular genetic approaches have uncovered a number of signaling components from both plants and microbes and their mode of actions. However, signaling pathways are highly interconnected and influenced by diverse sets of environmental factors. Therefore, it is important to have systems views in order to understand the true nature of plant–microbe interactions. Indeed, systems biology approaches have revealed previously overlooked or misinterpreted properties of the plant immune signaling network. Experimental reconstruction of biological networks using exhaustive combinatorial perturbations is particularly powerful to elucidate network structure and properties and relationships among network components. Recent advances in metagenomics of microbial communities associated with plants further point to the importance of systems approaches and open a research area of microbial community reconstruction. In this review, we highlight the importance of a systems understanding of plant–microbe interactions, with a special emphasis on reconstruction strategies

    Examine of the Facts of Women and Migration During the Urbanization in the Scale of South-eastern Anatolia Region (Gap), in Turkey

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    Since the beginning of 1950’s the migration of population from countryside to cities constitutes a subject as an important part of demographic changing on its own. Since the second half of 1970’s, especially domestic migration from the small and medium size cities to big cities, by turning into family migration became dense in the three big metropolises in west. (Ãstanbul, Ankara, Ãzmir). In 1990’s both the migration from east and Southeast Anatolia to other regions and the obligatory migration inside the region have been added to elements which effect movement of population. While this changing, which occurs in the dynamics of domestic migration during the time, does not exist in most of present researches, one of the other absence is social sex viewpoint. In the studies about migration, the lack of social sex viewpoint is not peculiar only to Turkey but also it seems limited in international literature. Present studies show there are important differences between women and men in the point of migration causes, participation to migration process, experiences during this process and effects of migration, attitudes and reactions of immigrants. In the core of these differences there are, collaboration inside the family between woman and man and parallel to this, social roles of woman and man, which described by customs and traditions. Women’ life relating to migration is generally closely related to their situations in family as a wife, a mother or a young girl about to marry. The relations between them and both the places they left and they just came is formed in this base. Consequently, in a migration process, which includes a social and place changing, identity of sex has an important role as much as socio-economic class, culture, ethnic or national identity. G.A.P. Region which is in the Southeast of our developing country has a village-city appearance by the effects of both many side social, physiological, economic and urban destruction which created by terror and fight and generally the feudal structure in the region, extreme poverty, lack of top and underground structure and the political and economic choices which does not mind about neighborhood values. This work has aimed at examine to migration which is one of the most important social fact in the world we live in the context of woman and urbanization and to expose the appearance of women in extent of G.A.P. region in domestic immigration…

    Effect of the Zero-Mode on the Response of a Trapped Bose-Condensed Gas

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    The dynamical response of a trapped Bose-Einstein condensate (BEC) is formulated consistently with quantum field theory and is numerically evaluated. We regard the BEC as a manifestation of the breaking of the global phase symmetry. Then, the Goldstone theorem implies the existence of a zero energy excitation mode (the zero-mode). We calculate the effect of the zero-mode on the response frequency and show that the contribution of the zero-mode to the first excitation mode is not so important in the parameter set realized in the existing experiment. This is the reason that experimental results can be described using the Bogoliubov prescription, although it breaks the consistency of the description in quantum field theory.Comment: 18 pages, 3 figure

    Nematic elastomers with aligned carbon nanotubes: new electromechanical actuators

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    We demonstrate, for the first time, the large electromechanical response in nematic liquid crystalline elastomers filled with a very low (~0.01%) concentration of carbon nanotubes, aligned along the nematic director at preparation. The nanotubes create a very large effective dielectric anisotropy of the composite. Their local field-induced torque is transmitted to the rubber-elastic network and is registered as the exerted uniaxial stress of order ~1kPa in response to a constant field of order ~1MV/m. We investigate the dependence of the effect on field strength, nanotube concentration and reproducibility under multiple field-on and -off cycles. The results indicate the potential of the nanotube-nematic elastomer composites as electrically driven actuators

    Comparing different accelerometer cut-points for sedentary time in children

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    Actigraph accelerometers are hypothesized to be valid measurements for assessing children\u27s sedentary time. However, there is considerable variation in accelerometer cut-points used. Therefore, we compared the most common accelerometer sedentary cut-points of children performing sedentary behaviors. Actigraph Actitrainer uniaxial accelerometers were used to measure children\u27s activity intensity (29 children, 5-11 years old) during different activities, namely playing computer games, nonelectronic sedentary games, watching television and playing outdoors. A structured protocol was the criterion for assessing the validity of four common cut-points (100, 300, 800, 1100 counts/minute). The median counts during all sedentary behaviors were below the lowest comparison cut-point of 100 cpm. The 75th percentile values for the sedentary behaviors were always below the cut-point of 300 cpm. Our results suggest that the cut-point of <100 cpm is the most appropriate

    The Texas construction sector: the tail that wagged the dog

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    The boom-to-bust days of the Texas construction industry will linger in people's memory for many years. D'Ann Petersen, Keith Phillips, and Mine Yucel examine the factors that led to the rise and fall of the Texas construction industry and determine the role the industry played in the state's volatile economy during the 1970s and 1980s. ; Petersen, Phillips, and Yucel employ an econometric model to analyze the roles residential and nonresidential construction played in the state's economic fluctuations from 1976 through 1990. The authors find that, although large swings in oil prices were the greatest source of economic instability in the Texas economy, the construction sector also played an important and independent role in the changing fortunes of the state. The authors' results show that the homebuilding sector, in particular, had a large impact on the Texas economy. In addition, the authors find that the state's economy needs several years to adjust to shocks in the construction industry. Consequently, the current expansion in residential construction is likely to have positive economic effects in the years ahead.Construction industry ; Texas

    Quantum Field Theoretical Analysis on Unstable Behavior of Bose-Einstein Condensates in Optical Lattices

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    We study the dynamics of Bose-Einstein condensates flowing in optical lattices on the basis of quantum field theory. For such a system, a Bose-Einstein condensate shows a unstable behavior which is called the dynamical instability. The unstable system is characterized by the appearance of modes with complex eigenvalues. Expanding the field operator in terms of excitation modes including complex ones, we attempt to diagonalize the unperturbative Hamiltonian and to find its eigenstates. It turns out that although the unperturbed Hamiltonian is not diagonalizable in the conventional bosonic representation the appropriate choice of physical states leads to a consistent formulation. Then we analyze the dynamics of the system in the regime of the linear response theory. Its numerical results are consitent with as those given by the discrete nonlinear Schrodinger equation.Comment: 16pages, 4figure

    Condition for the Existence of Complex Modes in a Trapped Bose--Einstein Condensate with a Highly Quantized Vortex

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    We consider a trapped Bose--Einstein condensate (BEC) with a highly quantized vortex. For the BEC with a doubly, triply or quadruply quantized vortex, the numerical calculations have shown that the Bogoliubov--de Gennes equations, which describe the fluctuation of the condensate, have complex eigenvalues. In this paper, we obtain the analytic expression of the condition for the existence of complex modes, using the method developed by Rossignoli and Kowalski [R. Rossignoli and A. M. Kowalski, Phys. Rev. A 72, 032101 (2005)] for the small coupling constant. To derive it, we make the two-mode approximation. With the derived analytic formula, we can identify the quantum number of the complex modes for each winding number of the vortex. Our result is consistent with those obtained by the numerical calculation in the case that the winding number is two, three or four. We prove that the complex modes always exist when the condensate has a highly quantized vortex

    Condition for emergence of complex eigenvalues in the Bogoliubov-de Gennes equations

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    The condition for the appearance of dynamical instability of the Bose-condensed system, characterized by the emergence of complex eigenvalues in the Bogoliubov-de Gennes equations, is studied analytically. We perturbatively expand both the Gross-Pitaevskii and Bogoliubov-de Gennes equations with respect to the coupling constant. It is concluded that the degeneracy between a positive-norm eigenmode and a negative-norm one is essential for the emergence of complex modes. Based on the conclusion, we justify the two-mode approximation applied in our previous work [E. Fukuyama \textit{et al}., Phys. Rev. A {\bf 76}, 043608 (2007)], in which we analytically studied the condition for the existence of complex modes when the condensate has a highly quantized vortex.Comment: 7page
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