216 research outputs found

    Potential distribution surrounding a photo- emitting plate in a dilute plasma

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    Potential distribution in photo-emitting plate in dilute plasma

    Correlation effects in semi-infinite plasmas

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    Pair correlations in ionized gas combined to half space by perfectly reflecting boundar

    Kinetic Equation for a Plasma and Its Application to High-frequency Conductivity

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    Kinetic equation for inhomogenious nonisotropic plasma and application to high frequency conductivit

    Letters of Credit—A Comparison of Article 5 of the Uniform Commercial Code and the Washington Practice [Part 1]

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    It is our hope that this discussion will serve a dual purpose: (1) provide a basis for evaluating the desirability of Article 5 and so aid in an over-all evaluation of the Uniform Commercial Code in this period of pre-enactment consideration of the Code\u27s merits, and (2) provide a point of departure for Washington bankers and lawyers who become concerned with letter of credit problems after enactment of the Code. The first of these objectives seems better served if we undertake with each section a critique of its operation in light of the existing practice. This we have done

    Letters of Credit—A Comparison of Article 5 of the Uniform Commercial Code and the Washington Practice [Part 2]

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    It is our hope that this discussion will serve a dual purpose: (1) provide a basis for evaluating the desirability of Article 5 and so aid in an over-all evaluation of the Uniform Commercial Code in this period of pre-enactment consideration of the Code\u27s merits, and (2) provide a point of departure for Washington bankers and lawyers who become concerned with letter of credit problems after enactment of the Code. The first of these objectives seems better served if we undertake with each section a critique of its operation in light of the existing practice. This we have done

    What are we downloading for our children? Best-selling children’s apps in four European countries

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    The present article provides an overview of the best-selling apps for the age range of 0–8 years under various categories, including ‘Kids’, ‘Books’, ‘Educational games’, ‘Family games’ and ‘Word games’ in the two major application stores (Google Play and iTunes App Store) in four economically diverse European countries: Hungary, Turkey, Greece and the Netherlands. As tablets seem to be a substantial part of children’s leisure activities, and thus apps might play an important role in their development, we conducted a content analysis to highlight two issues: the educational value of the most popular children’s apps and the fine-tuning of apps to the local culture and language of non-English speaking countries. There is a large overlap between the best-selling apps in the four countries; in fact, half of the apps appear among the most popular lists in more than one country. Consequently, most children’s apps do not include any oral language and, if they do, they are not available in the local language. Furthermore, the results show that a substantial part of the apps supported early literacy skills. In the majority of apps teaching literacy, although advertised for the youngest, the focus of instruction was more suited for school-age children

    Stem cells, senescence, neosis and self-renewal in cancer

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    We describe the basic tenets of the current concepts of cancer biology, and review the recent advances on the suppressor role of senescence in tumor growth and the breakdown of this barrier during the origin of tumor growth. Senescence phenotype can be induced by (1) telomere attrition-induced senescence at the end of the cellular mitotic life span (MLS*) and (2) also by replication history-independent, accelerated senescence due to inadvertent activation of oncogenes or by exposure of cells to genotoxins. Tumor suppressor genes p53/pRB/p16INK4A and related senescence checkpoints are involved in effecting the onset of senescence. However, senescence as a tumor suppressor mechanism is a leaky process and senescent cells with mutations or epimutations in these genes escape mitotic catastrophe-induced cell death by becoming polyploid cells. These polyploid giant cells, before they die, give rise to several cells with viable genomes via nuclear budding and asymmetric cytokinesis. This mode of cell division has been termed neosis and the immediate neotic offspring the Raju cells. The latter inherit genomic instability and transiently display stem cell properties in that they differentiate into tumor cells and display extended, but, limited MLS, at the end of which they enter senescent phase and can undergo secondary/tertiary neosis to produce the next generation of Raju cells. Neosis is repeated several times during tumor growth in a non-synchronized fashion, is the mode of origin of resistant tumor growth and contributes to tumor cell heterogeneity and continuity. The main event during neosis appears to be the production of mitotically viable daughter genome after epigenetic modulation from the non-viable polyploid genome of neosis mother cell (NMC). This leads to the growth of resistant tumor cells. Since during neosis, spindle checkpoint is not activated, this may give rise to aneuploidy. Thus, tumor cells also are destined to die due to senescence, but may escape senescence due to mutations or epimutations in the senescent checkpoint pathway. A historical review of neosis-like events is presented and implications of neosis in relation to the current dogmas of cancer biology are discussed. Genesis and repetitive re-genesis of Raju cells with transient "stemness" via neosis are of vital importance to the origin and continuous growth of tumors, a process that appears to be common to all types of tumors. We suggest that unlike current anti-mitotic therapy of cancers, anti-neotic therapy would not cause undesirable side effects. We propose a rational hypothesis for the origin and progression of tumors in which neosis plays a major role in the multistep carcinogenesis in different types of cancers. We define cancers as a single disease of uncontrolled neosis due to failure of senescent checkpoint controls

    Renormalized kinetic theory of classical fluids in and out of equilibrium

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    We present a theory for the construction of renormalized kinetic equations to describe the dynamics of classical systems of particles in or out of equilibrium. A closed, self-consistent set of evolution equations is derived for the single-particle phase-space distribution function ff, the correlation function C=C=, the retarded and advanced density response functions χR,A=δf/δϕ\chi^{R,A}=\delta f/\delta\phi to an external potential ϕ\phi, and the associated memory functions ΣR,A,C\Sigma^{R,A,C}. The basis of the theory is an effective action functional Ω\Omega of external potentials ϕ\phi that contains all information about the dynamical properties of the system. In particular, its functional derivatives generate successively the single-particle phase-space density ff and all the correlation and density response functions, which are coupled through an infinite hierarchy of evolution equations. Traditional renormalization techniques are then used to perform the closure of the hierarchy through memory functions. The latter satisfy functional equations that can be used to devise systematic approximations. The present formulation can be equally regarded as (i) a generalization to dynamical problems of the density functional theory of fluids in equilibrium and (ii) as the classical mechanical counterpart of the theory of non-equilibrium Green's functions in quantum field theory. It unifies and encompasses previous results for classical Hamiltonian systems with any initial conditions. For equilibrium states, the theory reduces to the equilibrium memory function approach. For non-equilibrium fluids, popular closures (e.g. Landau, Boltzmann, Lenard-Balescu) are simply recovered and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.Comment: 63 pages, 10 figure
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