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Journal articles on the topic 'Primitives de diffusion'

Author: Grafiati
Published: 9 July 2022

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1

Ye, Heng-Qing, and David D. Yao. "Diffusion Approximation for Fair Resource Control—Interchange of Limits Under a Moment Condition." Mathematics of Operations Research 46, no. 3 (August 2021): 869–94. http://dx.doi.org/10.1287/moor.2020.1065.

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In a prior study [Ye HQ, Yao DD (2016) Diffusion limit of fair resource control–Stationary and interchange of limits. Math. Oper. Res. 41(4):1161–1207.] focusing on a class of stochastic processing network with fair resource control, we justified the diffusion approximation (in the context of the interchange of limits) provided that the pth moment of the workloads are bounded. To this end, we introduced the so-called bounded workload condition, which requires the workload process be bounded by a free process plus the initial workload. This condition is for a derived process, the workload, as opposed to primitives such as arrival processes and service requirements; as such, it could be difficult to verify. In this paper, we establish the interchange of limits under a moment condition of suitable order on the primitives directly: the required order is [Formula: see text] on the moments of the primitive processes so as to bound the pth moment of the workload. This moment condition is trivial to verify, and indeed automatically holds in networks where the primitives have moments of all orders, for instance, renewal arrivals with phase-type interarrival times and independent and identically distributed phase-type service times.
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2

Zhang, Leo Yu, Yushu Zhang, Yuansheng Liu, Anjia Yang, and Guanrong Chen. "Security Analysis of Some Diffusion Mechanisms Used in Chaotic Ciphers." International Journal of Bifurcation and Chaos 27, no. 10 (September 2017): 1750155. http://dx.doi.org/10.1142/s0218127417501553.

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As a variant of the substitution–permutation network, the permutation–diffusion structure has received extensive attention in the field of chaotic cryptography over the last three decades. Because of the high implementation speed and nonlinearity over GF([Formula: see text]), the Galois field of two elements, mixing modulo addition/multiplication and Exclusive OR becomes very popular in various designs to achieve the desired diffusion effect. This paper reports that some diffusion mechanisms based on modulo addition/multiplication and Exclusive OR are not resistant to plaintext attacks as claimed. By cracking several recently proposed chaotic ciphers as examples, it is demonstrated that a good understanding of the strength and weakness of these crypto-primitives is crucial for designing more practical chaotic encryption algorithms in the future.
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3

Bollu, Tejapratap, Samuel C. Whitehead, Nikil Prasad, Jackson Walker, Nitin Shyamkumar, Raghav Subramaniam, Brian Kardon, Itai Cohen, and Jesse H. Goldberg. "Automated home cage training of mice in a hold-still center-out reach task." Journal of Neurophysiology 121, no. 2 (February 1, 2019): 500–512. http://dx.doi.org/10.1152/jn.00667.2018.

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An obstacle to understanding neural mechanisms of movement is the complex, distributed nature of the mammalian motor system. Here we present a novel behavioral paradigm for high-throughput dissection of neural circuits underlying mouse forelimb control. Custom touch-sensing joysticks were used to quantify mouse forelimb trajectories with micron-millisecond spatiotemporal resolution. Joysticks were integrated into computer-controlled, rack-mountable home cages, enabling batches of mice to be trained in parallel. Closed loop behavioral analysis enabled online control of reward delivery for automated training. We used this system to show that mice can learn, with no human handling, a direction-specific hold-still center-out reach task in which a mouse first held its right forepaw still before reaching out to learned spatial targets. Stabilogram diffusion analysis of submillimeter-scale micromovements produced during the hold demonstrate that an active control process, akin to upright balance, was implemented to maintain forepaw stability. Trajectory decomposition methods, previously used in primates, were used to segment hundreds of thousands of forelimb trajectories into millions of constituent kinematic primitives. This system enables rapid dissection of neural circuits for controlling motion primitives from which forelimb sequences are built. NEW & NOTEWORTHY A novel joystick design resolves mouse forelimb kinematics with micron-millisecond precision. Home cage training is used to train mice in a hold-still center-out reach task. Analytical methods, previously used in primates, are used to decompose mouse forelimb trajectories into kinematic primitives.
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4

Noura, Hassan, Christophe Guyeux, Ali Chehab, Mohammad Mansour, and Raphaël Couturier. "Efficient Chaotic Encryption Scheme with OFB Mode." International Journal of Bifurcation and Chaos 29, no. 05 (May 2019): 1950059. http://dx.doi.org/10.1142/s0218127419500597.

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Data confidentiality is mandatory during transmission or when storing sensitive information, especially in financial, medical and military applications. In this context, several cipher solutions and techniques have been presented in the literature. However, existing solutions are mainly based on static structures, where the confusion and diffusion primitives are fixed and independent of the secret key. In this article, we propose a new block cipher scheme that is based on the Substitution Permutation Networks (SPN). The proposed cipher consists of three operations: round-key addition, substitution, and bits’ permutation. Moreover, the substitution operation is applied at the byte level and it is based on a dynamically generated S-box, while the diffusion primitives are applied at the bit level using a dynamically generated P-box. Such key-dependent design ensures better cryptographic strength and system performance when compared, for instance, to DES, 3DES, RC5, and PRESENT schemes, among others, due to its key expansion algorithm. Thorough analysis show that the proposed scheme exhibits a high degree of randomness, key and plain-text sensitivity, and it satisfies the avalanche effect. From a theoretical perspective, we have formulated the Output Feedback mode of operation as a discrete dynamical system on a topological space. We prove that the dynamics of this system (in terms of sensitivity to the initial vector, etc.) are directly related to the strong connectivity of a graph. By doing so, we are able to characterize the conditions under which this mode evolves chaotically, as defined in Devaney’s theory. In particular, such theoretical investigations allow us to link the avalanche effect and key sensitivity of the cipher with the sensitivity of the whole process, that is, with the mode of operation.
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DORINI, LEYZA BALDO, and NEUCIMAR JERÔNIMO LEITE. "A SELF-DUAL FILTERING TOGGLE OPERATOR FOR SPECKLE NOISE FILTERING." International Journal of Image and Graphics 13, no. 03 (July 2013): 1350015. http://dx.doi.org/10.1142/s0219467813500150.

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In this work, we formalize an alternative way to build self-dual morphological filters that extends some results obtained for morphological centers to a different class of toggle operators. Thus, a wider range of primitives can be considered without causing oscillations, a common problem in toggle mappings. We also show that the combination of the morphological filters generated by using the proposed approach with the well-known anisotropic diffusion technique yields sound results where homogeneous regions are smoothed without degrading edge information. We explore the filtering of speckle noise, an interference pattern that causes a granular aspect in the image, thus limiting its interpretation and making it difficult further image processing tasks. Experimental tests on both synthetic and real-world images show promising results when compared to some well-known methods related to this type of filtering.
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6

Richman, Karen. "Peasants, Migrants and the Discovery of African Traditions: Ritual and Social Change In Lowland Haiti." Journal of Religion in Africa 37, no. 3 (2007): 371–97. http://dx.doi.org/10.1163/157006607x211978.

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AbstractObservers of Haitian popular religion have defined Vodou as the authentic African religion of Haitian peasants. In fact, Vodou's congregational forms and practices evolved in and around Port-au-Prince during the twentieth century as the local peasantry was being coerced into wage labor. This paper deals with the incorporation of these ritual innovations in a particular hamlet in Léogane. The agents of ritual diffusion appear to have been not only redundant peasants and neophyte proletarians circulating between the capital city and the nearby plain, but also ethnologists who moved between privileged sites of the Vodou laboratory. The scientific valorization of the heroic slave religion was a centerpiece of the Haitian ethnologists' counter-narrative to European cultural hegemony and North American colonialism. Though their approach to Vodou was part of counter-hegemonic, nationalist discourse, it nonetheless recapitulated a modern view of tradition-bound primitives.
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7

Martynova, Inna A. "METHODOLOGICAL SUPPORT FOR THE DIVIDING OF FACTORIAL SETS SUBSTITUTIONS." АВТОМАТИЗАЦИЯ ПРОЦЕССОВ УПРАВЛЕНИЯ 63, no. 1 (2021): 91–97. http://dx.doi.org/10.35752/1991-2927-2021-1-63-91-97.

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The substitution and permutation functions are the main functions of information cryptographic systems that provide diffusion and mixing of information. It is required to analyze these cryptographic primitives while creating new algorithms for data transformation using such functions. A new scale of notation has been proposed for performing such analysis. This is the factorial sets statistical series notation scale. This scale of notation helps to index the factorial sets statistical series elements and establish a one-to-one correspondence between the number and a specific type of substitution. The use of this system provides a way to find new characteristics and properties of substitutions. Since substitutions of the factorial sets form a cyclic group, the operation on elements of this group can be determined. In the general case, the operation used is a multiplication of substitutions, but this paper suggests another operation for group determination. The article presents a capability for dividing the factorial sets substitutions. Two methods for implementing the substitution division operations are proposed such as a method of successive transition and a method of group transition, which are implemented through non commutative operation of multiplying on inverted substitutions.
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8

Klisch, J., H. Husstedt, S. Hennings, V. v. Velthoven, A. Pagenstecher, and M. Schumacher. "Supratentorial primitive neuroectodermal tumours: diffusion-weighted MRI." Neuroradiology 42, no. 6 (June 21, 2000): 393–98. http://dx.doi.org/10.1007/s002340000318.

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9

Ruggiero, G. A., Y. Ourmières, E. Cosme, J. Blum, D. Auroux, and J. Verron. "Data assimilation experiments using the diffusive back and forth nudging for the NEMO ocean model." Nonlinear Processes in Geophysics Discussions 1, no. 2 (July 16, 2014): 1073–131. http://dx.doi.org/10.5194/npgd-1-1073-2014.

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Abstract. The Diffusive Back and Forth Nudging (DBFN) is an easy-to-implement iterative data assimilation method based on the well-known Nudging method. It consists in a sequence of forward and backward model integrations, within a given time window, both of them using a feedback term to the observations. Therefore in the DBFN, the Nudging asymptotic behavior is translated into an infinite number of iterations within a bounded time domain. In this method, the backward integration is carried out thanks to what is called backward model, which is basically the forward model with reversed time step sign. To maintain numeral stability the diffusion terms also have their sign reversed, giving a diffusive character to the algorithm. In this article the DBFN performance to control a primitive equation ocean model is investigated. In this kind of model non-resolved scales are modeled by diffusion operators which dissipate energy that cascade from large to small scales. Thus, in this article the DBFN approximations and their consequences on the data assimilation system set-up are analyzed. Our main result is that the DBFN may provide results which are comparable to those produced by a 4Dvar implementation with a much simpler implementation and a shorter CPU time for convergence.
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10

Ruggiero, G. A., Y. Ourmières, E. Cosme, J. Blum, D. Auroux, and J. Verron. "Data assimilation experiments using diffusive back-and-forth nudging for the NEMO ocean model." Nonlinear Processes in Geophysics 22, no. 2 (April 29, 2015): 233–48. http://dx.doi.org/10.5194/npg-22-233-2015.

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Abstract. The diffusive back-and-forth nudging (DBFN) is an easy-to-implement iterative data assimilation method based on the well-known nudging method. It consists of a sequence of forward and backward model integrations, within a given time window, both of them using a feedback term to the observations. Therefore, in the DBFN, the nudging asymptotic behaviour is translated into an infinite number of iterations within a bounded time domain. In this method, the backward integration is carried out thanks to what is called backward model, which is basically the forward model with reversed time step sign. To maintain numeral stability, the diffusion terms also have their sign reversed, giving a diffusive character to the algorithm. In this article the DBFN performance to control a primitive equation ocean model is investigated. In this kind of model non-resolved scales are modelled by diffusion operators which dissipate energy that cascade from large to small scales. Thus, in this article, the DBFN approximations and their consequences for the data assimilation system set-up are analysed. Our main result is that the DBFN may provide results which are comparable to those produced by a 4Dvar implementation with a much simpler implementation and a shorter CPU time for convergence. The conducted sensitivity tests show that the 4Dvar profits of long assimilation windows to propagate surface information downwards, and that for the DBFN, it is worth using short assimilation windows to reduce the impact of diffusion-induced errors. Moreover, the DBFN is less sensitive to the first guess than the 4Dvar.
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11

Ngai, K. L., Marian Paluch, and Cristian Rodríguez-Tinoco. "Why is surface diffusion the same in ultrastable, ordinary, aged, and ultrathin molecular glasses?" Physical Chemistry Chemical Physics 19, no. 44 (2017): 29905–12. http://dx.doi.org/10.1039/c7cp05357f.

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12

Chen, Ruei-Tang, Chih-Chieh Kang, Jeng-Feng Lin, Sheng-Wei Chiou, Hung-Hsiang Cheng, and Chih-Wen Lai. "Novel Design for a Diffusive Solar Cell Window." Journal of Nanomaterials 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/675312.

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Building integrated photovoltaics (BIPV) are an important application of future solar energy development. The incorporation of solar cells into windows must not only maintain indoor natural lighting but also generate electrical power at the same time. In our continuing effort to improve the design of diffusion solar window, a more fundamental and efficient three-layer structure—glass/EVA with TiO2nanoparticles embedded/glass—was proposed. In this work, a well-established ASAP ray-tracing model for a diffusive solar cell window was implemented to validate the outperformance of three-layer structure over primitive five-layer structure. Optical simulations were also implemented to perform its primary design for the determination of the optimal design parameters, such as the glass thickness, the EVA thickness, and the weight concentration of TiO2nanoparticles. Based on the simulation results, an optimal design for a three-layer diffusive solar cell window prototype was proposed. And the influence of both EVA thickness and glass thickness on the power edge-exitance (solar cell power generation efficiency) of a DSCW was thoroughly investigated.
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13

KUZNETSOV, E. A. "Mixed Lagrangian–Eulerian description of vortical flows for ideal and viscous fluids." Journal of Fluid Mechanics 600 (March 26, 2008): 167–80. http://dx.doi.org/10.1017/s0022112008000281.

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It is shown that the Euler hydrodynamics for vortical flows of an ideal fluid is equivalent to the equations of motion of a charged compressible fluid moving due to a self-consistent electromagnetic field. The velocity of new auxiliary fluid coincides with the velocity component normal to the vorticity line for the primitive equations. Therefore this new hydrodynamics represents hydrodynamics of vortex lines. Their compressibility reveals a new mechanism for three-dimensional incompressible vortical flows connected with breaking (or overturning) of vortex lines which can be considered as one of the variants of collapses. Transition to the Lagrangian description in the new hydrodynamics corresponds, for the original Euler equations, to a mixed Lagrangian–Eulerian description – the vortex line representation (VLR). The Jacobian of this mapping defines the density of vortex lines. It is shown also that application of VLR to the Navier–Stokes equations results in an equation of diffusive type for the Cauchy invariant. The diffusion tensor for this equation is defined by the VLR metric.
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14

Niskanen, Eero, Christian Chatelain, and Michel Symann. "Diffusion chamber colony-forming unit (cfu-d): A primitive stem cell." International Journal of Cell Cloning 7, no. 6 (1989): 330–42. http://dx.doi.org/10.1002/stem.5530070602.

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15

DECAMPS, MARC, MARC GOOVAERTS, and WIM SCHOUTENS. "SELF EXCITING THRESHOLD INTEREST RATES MODELS." International Journal of Theoretical and Applied Finance 09, no. 07 (November 2006): 1093–122. http://dx.doi.org/10.1142/s0219024906003937.

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In this paper, we study a new class of tractable diffusions suitable for model's primitives of interest rates. We consider scalar diffusions with scale s′(x) and speed m(x) densities discontinuous at the level x*. We call that family of processes Self Exciting Threshold (SET) diffusions. Following Gorovoi and Linetsky [18], we obtain semi-analytical expressions for the transition density of SET (killed) diffusions. We propose several applications to interest rates modeling. We show that SET short rate processes do not generate arbitrage possibilities and we adapt the HJM procedure to forward rates with discontinuous scale density. We also extend the CEV and the shifted-lognormal LIBOR market models. Finally, the models are calibrated to the US market. SET diffusions can also be used to model stock price, stochastic volatility, credit spread, etc.
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16

Chen, Gang, and Alan Plumb. "Effective Isentropic Diffusivity of Tropospheric Transport." Journal of the Atmospheric Sciences 71, no. 9 (August 28, 2014): 3499–520. http://dx.doi.org/10.1175/jas-d-13-0333.1.

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Abstract Tropospheric transport can be described qualitatively by the slow mean diabatic circulation and rapid isentropic mixing, yet a quantitative understanding of the transport circulation is complicated, as nearly half of the isentropic surfaces in the troposphere frequently intersect the ground. A theoretical framework for the effective isentropic diffusivity of tropospheric transport is presented. Compared with previous isentropic analysis of effective diffusivity, a new diagnostic is introduced to quantify the eddy diffusivity of the near-surface isentropic flow. This diagnostic also links the effective eddy diffusivity directly to a diffusive closure of eddy fluxes through a finite-amplitude wave activity equation. The theory is examined in a dry primitive equation model on the sphere. It is found that the upper troposphere is characterized by a diffusivity minimum at the jet’s center with enhanced mixing at the jet’s flanks and that the lower troposphere is dominated by stronger mixing throughout the baroclinic zone. This structure of isentropic diffusivity is generally consistent with the diffusivity obtained from the geostrophic component of the flow. Furthermore, the isentropic diffusivity agrees broadly with the tracer equivalent length obtained from either a spectral diffusion scheme or a semi-Lagrangian advection scheme, indicating that the effective diffusivity of tropospheric transport is largely dictated by large-scale stirring rather than details of the small-scale diffusion acting on the tracers.
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17

Henning, Cara C., and Geoffrey K. Vallis. "The Effects of Mesoscale Eddies on the Main Subtropical Thermocline." Journal of Physical Oceanography 34, no. 11 (November 1, 2004): 2428–43. http://dx.doi.org/10.1175/jpo2639.1.

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Abstract The effects of mesoscale eddies on the main subtropical thermocline are explored using a simply configured wind- and buoyancy-driven primitive equation numerical model in conjunction with transformed Eulerian mean diagnostics and simple scaling ideas and closure schemes. If eddies are suppressed by a modest but nonnegligible horizontal diffusion and vertical diffusion is kept realistically small, the model thermocline exhibits a familiar two-regime structure with an upper, advectively dominated ventilated thermocline and a lower, advective– diffusive internal thermocline, and together these compose the main thermocline. If the horizontal resolution is sufficiently high and the horizontal diffusivity is sufficiently low, then a vigorous mesoscale eddy field emerges. In the mixed layer and upper-mode-water regions, the divergent eddy fluxes are manifestly across isopycnals and so have a diabatic effect. Beneath the mixed layer, the mean structure of the upper (i.e., ventilated) thermocline is still found to be dominated by mean advective terms, except in the “mode water” region and close to the western boundary current. The eddies are particularly strong in the mode-water region, and the low-potential-vorticity pool of the noneddying case is partially eroded away as the eddies try to flatten the isopycnals and reduce available potential energy. The intensity of the eddies decays with depth more slowly than does the mean flow, leading to a three-way balance among eddy flux convergence, mean flow advection, and diffusion in the internal thermocline. Eddies subduct water along isopycnals from the surface into the internal thermocline, replenishing its water masses and maintaining its thickness. Just as in the noneddying case, the dynamics of the internal thermocline can be usefully expressed as an advective–diffusive balance, but where advection is now by the residual (eddy-induced plus Eulerian mean) circulation. The eddy-induced advection partially balances the mean upwelling through the base of the thermocline, and this leads to a slightly thicker thermocline than in the noneddying case. The results suggest that as the diffusivity goes to zero, the residual circulation will go to zero but the thickness of the internal thermocline may remain finite, provided eddy activity persists.
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Henning, Cara C., and Geoffrey K. Vallis. "The Effects of Mesoscale Eddies on the Stratification and Transport of an Ocean with a Circumpolar Channel." Journal of Physical Oceanography 35, no. 5 (May 1, 2005): 880–96. http://dx.doi.org/10.1175/jpo2727.1.

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Abstract The effects of eddies in a primitive equation ocean model configured in a single hemisphere domain with circumpolar channels at their poleward ends are investigated; in particular, two regimes for the mass balance in the channel are investigated. With small overlying winds, the channel stratification is largely set by diffusion operating in the gyre portion of the domain: the depth scale varies with a fractional power of the diffusivity but has little dependence on the wind stress. As the winds are increased, the depth becomes increasingly controlled by a tendency toward small residual circulation. In this limit, a scaling theory is derived for the stratification in the channel that predicts the overall depth of the thermocline as a power of the wind stress and that allows the eddy length scale to differ from the channel length scale. The predicted depth depends on the details of the closure chosen for the eddy buoyancy flux, but in general it varies as some fractional power of the wind stress, and a channel-only numerical simulation agrees well with this prediction. When a gyre region is added to the channel, vertical diffusion in the gyre exerts some control on the channel stratification even at higher winds, forcing the mass balance into a mixed regime in which both eddy and diffusive effects are important. The depth scale varies less with the wind stress than in a channel-only configuration, and the residual mean circulation in the channel is maintained by the convergence of cross-isopycnal eddy buoyancy fluxes.
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Niskanen, Eero, and George Sigounas. "Radioprotective potential of primitive hematopoietic precursors forming colonies in diffusion chambers in mice." European Journal of Haematology 50, no. 2 (April 24, 2009): 118–21. http://dx.doi.org/10.1111/j.1600-0609.1993.tb00151.x.

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20

Cozzani, E., F. Rongioletti, A. Agnoletti, M. Bergamaschi, M. Burlando, and A. Parodi. "Un cas de cryptococcose cutanée primitive sans diffusion systémique chez un patient immunodéprimé." Annales de Dermatologie et de Vénéréologie 142, no. 12 (December 2015): S698—S699. http://dx.doi.org/10.1016/j.annder.2015.10.160.

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21

Xie, Yan, Jie Cheng, Benzhuo Lu, and Linbo Zhang. "Parallel Adaptive Finite Element Algorithms for Solving the Coupled Electro-diffusion Equations." Computational and Mathematical Biophysics 1 (April 24, 2013): 90–108. http://dx.doi.org/10.2478/mlbmb-2013-0005.

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Abstractrithms for solving the 3D electro-diffusion equations such as the Poisson-Nernst-Planck equations and the size-modified Poisson-Nernst-Planck equations in simulations of biomolecular systems in ionic liquid. A set of transformation methods based on the generalized Slotboom variables is used to solve the coupled equations. Calculations of the diffusion-reaction rate coefficients, electrostatic potential and ion concentrations for various systems verify the method’s validity and stability. The iterations between the Poisson equation and the Nernst- Planck equations in the primitive method and in the transformation method are compared to illustrate how the new method accelerates the convergence of the solution. To speed up the convergence, we introduce the DIIS (direct inversion of the iterative subspace) method including Simple Mixing and Anderson Mixing as under-relaxation techniques, the effectiveness of which on acceleration is shown by numerical tests. It is worth noting that the primitive method fails to solve the size-modified Poisson-Nernst-Planck equations for real protein systems but the transformation method succeeds in the simulations of the ACh-AChE reaction system and the DNA fragment. To improve the accuracy of the solution, we introduce high order elements and mesh adaptation based on an a posteriori error estimator. Numerical results indicate that our mesh adaptation process leads to quasi-optimal convergence. We implement our algorithms using the parallel adaptive finite element package PHG [53] and high parallel efficiency is obtained.
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22

Monnard, Pierre-Alain, Andrej Luptak, and David W. Deamer. "Models of primitive cellular life: polymerases and templates in liposomes." Philosophical Transactions of the Royal Society B: Biological Sciences 362, no. 1486 (May 2007): 1741–50. http://dx.doi.org/10.1098/rstb.2007.2066.

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Nutrient transport, polymerization and expression of genetic information in cellular compartments are hallmarks of all life today, and must have appeared at some point during the origin and early evolution of life. Because the first cellular life lacked membrane transport systems based on highly evolved proteins, they presumably depended on simpler processes of nutrient uptake. Using a system consisting of an RNA polymerase and DNA template entrapped in submicrometre-sized lipid vesicles (liposomes), we found that the liposome membrane could be made sufficiently permeable to allow access of ionized substrate molecules as large as nucleoside triphosphates (NTPs) to the enzyme. The encapsulated polymerase transcribed the template-specific base sequences of the DNA to the RNA that was synthesized. These experiments demonstrate that units of genetic information can be associated with a functional catalyst in a single compartment, and that transcription of gene-sized DNA fragments can be achieved by relying solely on passive diffusion to supply NTPs substrates.
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Ferrano, Fabian, Marco Speich, Wolfgang Rimkus, Markus Merkel, and Andreas Öchsner. "Simulation of the Impact Behaviour of Diffusion-Bonded and Adhered Perforated Hollow Sphere Structures (PHSS)." Defect and Diffusion Forum 294 (December 2009): 27–38. http://dx.doi.org/10.4028/www.scientific.net/ddf.294.27.

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This paper investigates the mechanical properties of a new type of hollow sphere structure. For this new type, the sphere shell is perforated by several holes in order to open up the inner sphere volume and surface. The mechanical behaviour of perforated sphere structures under large deformations and strains in a primitive cubic arrangement is numerically evaluated by using the finite element method for different hole diameters and different joining techniques.
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George, Ken. "What Happened to Primitive Cornish /I/ When Long in Closed Syllables?" Studia Celtica Posnaniensia 3, no. 1 (January 1, 2018): 5–31. http://dx.doi.org/10.2478/scp-2018-0001.

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Abstract Of the four unrounded front vowels in Primitive Cornish, /i/, /ɛ/ and /a/ remained stable when long in closed syllables, but /ɪ/ had a tendency to fall together with /ɛ/. Jackson (1953) and Williams (1995) dated this change to the twelfth century, but the present research indicates that in most words, the change took place substantially later. An analysis of spellings and of rhymes show that not all words changed at the same time. Most stressed monosyllables in historical /-ɪz/ were pronounced [-ɪːz] in Middle Cornish and [-ɛːz] in Late Cornish. Those with historical /-ɪð/ and /-ɪθ/ were dimorphic in Middle Cornish (i.e. they were spelled with both <y~i> and <e>), showing the sound-change in progress during that time. The process of change from [ɪː] to [ɛː] was one of lexical diffusion. The implications for the revived language are briefly examined.
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Cao, Chongsheng, Jinkai Li, and Edriss S. Titi. "Global Well-Posedness of the Three-Dimensional Primitive Equations with Only Horizontal Viscosity and Diffusion." Communications on Pure and Applied Mathematics 69, no. 8 (April 30, 2015): 1492–531. http://dx.doi.org/10.1002/cpa.21576.

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Hieber, Matthias, Amru Hussein, and Takahito Kashiwabara. "Global strong L well-posedness of the 3D primitive equations with heat and salinity diffusion." Journal of Differential Equations 261, no. 12 (December 2016): 6950–81. http://dx.doi.org/10.1016/j.jde.2016.09.010.

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Cao, Chongsheng, and Edriss S. Titi. "Global Well–Posedness of the 3D Primitive Equations with Partial Vertical Turbulence Mixing Heat Diffusion." Communications in Mathematical Physics 310, no. 2 (January 17, 2012): 537–68. http://dx.doi.org/10.1007/s00220-011-1409-4.

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Shi, Hong-Bing, Guang-Hua Gao, and Yang-Xin Yu. "Self-diffusion coefficients of ions in primitive model electrolyte solutions by smart Brownian dynamics simulation." Fluid Phase Equilibria 228-229 (February 2005): 535–40. http://dx.doi.org/10.1016/j.fluid.2004.09.027.

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29

Demuynck, Fabien, Yann Drean, Julie Morvan, Henri Sevestre, Jean Gondry, and Alain Le Blanche. "Primitive lymphoma of the uterine cervix: 3-T MR diffusion imaging and PET-CT features." European Journal of Radiology Extra 71, no. 1 (July 2009): e33-e36. http://dx.doi.org/10.1016/j.ejrex.2009.01.006.

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30

Down, Julian D., Kalindi Parmar, James Clyne, Peter M. Mauch, and Robert Sackstein. "Defining the Bone Marrow Stem Cell Niche According to a Hoechst Dye Diffusion Gradient and Hypoxia." Blood 104, no. 11 (November 16, 2004): 666. http://dx.doi.org/10.1182/blood.v104.11.666.666.

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Abstract The spatial organization of hematopoietic cell subsets of differing proliferative potential within the bone marrow microenvironment has come under increasing interest. In particular, it has been suggested that hematopoietic stem cells (HSCs) normally reside in a regulatory niche situated at the endosteal bone surface and in close proximity to osteoblasts. In the present study we have investigated how different hematopoietic cell subsets are distributed along a Hoechst dye perfusion gradient that may reflect the distance from marrow blood vessels and the level of oxygenation. C57BL/6J mice were intravenously injected with two doses of Hoechst 33342 at 10 and 5 min before marrow cell harvesting, a period that we determined was insufficient for active dye exclusion in vitro. Flow cytometric analysis revealed a wide distribution of Hoechst staining over 3 logs fluorescence intensity. The cells were then sorted from 6 different regions of the Hoechst gradient and evaluated for short- and long-term in vitro repopulating cells in the cobblestone area-forming cell (CAFC) assay. The primitive CAFC subset appearing at day 28 in culture was shown to be progressively enriched with decreasing Hoechst fluorescence while the short-term repopulating day 7 CAFC subset frequencies was the highest at an intermediate level of Hoechst staining. We further investigated whether primitive HSCs exist in a very low oxygen tension by administering the reductive 2-nitroimidazole compound pimonidazole in vivo and performed flow cytometric analysis on sorted primitive HSCs residing in high Hoechst dye effluxing side population (SP). In comparison to whole bone marrow or non-SP cells, the SP fraction showed increased intracellular staining with an anti-pimonidazole antibody that recognizes pimonidazole adducts formed only under hypoxic conditions (less than pO2 of 10 mm Hg). Comparison with thymocytes that are already known to be hypoxic in vivo (Hale et al. Am J Physiol Heart Circ Physiol282: H1467–H1477, 2002) showed both low Hoechst dye perfusion and positive anti-pimonidazole antibody staining. These results represent the first direct evidence that the hematopoietic cell hierarchy is spatially organized in relation to blood vessels and that the stem cell niche exists at the lowest end of an oxygen gradient. These findings have important implications in hematopoiesis and stem cell lodgement, and suggest that the location of hematopoietic stem cells in situ may render them more resistant to oxygen-dependent mutagenic and cytotoxic agents.
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Seo, Hwajeong, Hyeokdong Kwon, Hyunji Kim, and Jaehoon Park. "ACE: ARIA-CTR Encryption for Low-End Embedded Processors." Sensors 20, no. 13 (July 6, 2020): 3788. http://dx.doi.org/10.3390/s20133788.

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In this paper, we present the first optimized implementation of ARIA block cipher on low-end 8-bit Alf and Vegard’s RISC processor (AVR) microcontrollers. To achieve high-speed implementation, primitive operations, including rotation operation, a substitute layer, and a diffusion layer, are carefully optimized for the target low-end embedded processor. The proposed ARIA implementation supports the electronic codebook (ECB) and the counter (CTR) modes of operation. In particular, the CTR mode of operation is further optimized with the pre-computed table of two add-round-key, one substitute layer, and one diffusion layer operations. Finally, the proposed ARIA-CTR implementations on 8-bit AVR microcontrollers achieved 187.1, 216.8, and 246.6 clock cycles per byte for 128-bit, 192-bit, and 256-bit security levels, respectively. Compared with previous reference implementations, the execution timing is improved by 69.8%, 69.6%, and 69.5% for 128-bit, 192-bit, and 256-bit security levels, respectively.
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Cha, Hyung Jin, Jae-Hee Jeong, and Yeon-Gil Kim. "Crystallization and preliminary X-ray crystallographic analysis of PBPD2 fromListeria monocytogenes." Acta Crystallographica Section F Structural Biology Communications 70, no. 4 (March 25, 2014): 535–37. http://dx.doi.org/10.1107/s2053230x14005470.

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Penicillin-binding proteins (PBPs), which mediate the peptidoglycan biosynthetic pathway in the bacterial cell wall, have been intensively investigated as a target for the design of antibiotics. In this study, PBPD2, a low-molecular-weight PBP encoded bylmo2812fromListeria monocytogenes, was overexpressed inEscherichia coli, purified and crystallized at 295 K using the sitting-drop vapour-diffusion method. The crystal belonged to the primitive orthorhombic space groupP212121, with unit-cell parametersa= 37.7,b= 74.7,c= 75.1 Å, and diffracted to 1.55 Å resolution. There was one molecule in the asymmetric unit. The preliminary structure was determined by the molecular-replacement method.
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33

Long, Yang, and Indrek S. Wichman. "Theoretical and numerical analysis of a spreading opposed-flow diffusion flame." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 465, no. 2110 (July 29, 2009): 3209–38. http://dx.doi.org/10.1098/rspa.2009.0152.

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This article describes the macroscopic and microscopic features of flames spreading over solid-fuel surfaces by examining and comparing three models. The first model examines ignition and flame spread over a solid-fuel surface using a two-dimensional numerical simulation code. This model employs variable density, variable thermophysical properties and one-step global finite-rate chemistry. The second model, a macroscopic ‘field’ model, is solved in terms of the mixture fraction ( Z ) and total enthalpy ( H ) functions. Comparisons are made with numerical predictions for primitive quantities: temperature, species distributions and velocity fields; and derived quantities: heat flux, mass flux, mixture fraction, enthalpy function and flame stretch rate. The third model yields a ‘localized’ flame structure description near the flame attachment point. Theoretical formulas are produced for the quenching distance, the leading edge heat flux, and the flame structure, as characterized by reactivity, temperature field and species distributions. The analytical predictions are compared with numerical simulations to derive flame microstructure scaling parameters.
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Xu, Yuenong, and Mitchell D. Smooke. "Application of a Primitive Variable Newton's Method for the Calculation of an Axisymmetric Laminar Diffusion Flame." Journal of Computational Physics 104, no. 1 (January 1993): 99–109. http://dx.doi.org/10.1006/jcph.1993.1012.

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35

Guo, Boling, Daiwen Huang, and Wei Wang. "Diffusion limit of 3D primitive equations of the large-scale ocean under fast oscillating random force." Journal of Differential Equations 259, no. 6 (September 2015): 2388–407. http://dx.doi.org/10.1016/j.jde.2015.03.041.

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36

Erdem, E., R. A. Zimmerman, J. C. Haselgrove, L. T. Bilaniuk, and J. V. Hunter. "Diffusion-weighted imaging and fluid attenuated inversion recovery imaging in the evaluation of primitive neuroectodermal tumors." Neuroradiology 43, no. 11 (November 2001): 927–33. http://dx.doi.org/10.1007/s002340100603.

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37

King, Martin D., and Matthew Grech-Sollars. "A Bayesian spatial random effects model characterisation of tumour heterogeneity implemented using Markov chain Monte Carlo (MCMC) simulation." F1000Research 5 (August 26, 2016): 2082. http://dx.doi.org/10.12688/f1000research.9355.1.

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The focus of this study is the development of a statistical modelling procedure for characterising intra-tumour heterogeneity, motivated by recent clinical literature indicating that a variety of tumours exhibit a considerable degree of genetic spatial variability. A formal spatial statistical model has been developed and used to characterise the structural heterogeneity of a number of supratentorial primitive neuroectodermal tumours (PNETs), based on diffusion-weighted magnetic resonance imaging. Particular attention is paid to the spatial dependence of diffusion close to the tumour boundary, in order to determine whether the data provide statistical evidence to support the proposition that water diffusivity in the boundary region of some tumours exhibits a deterministic dependence on distance from the boundary, in excess of an underlying random 2D spatial heterogeneity in diffusion. Tumour spatial heterogeneity measures were derived from the diffusion parameter estimates obtained using a Bayesian spatial random effects model. The analyses were implemented using Markov chain Monte Carlo (MCMC) simulation. Posterior predictive simulation was used to assess the adequacy of the statistical model. The main observations are that the previously reported relationship between diffusion and boundary proximity remains observable and achieves statistical significance after adjusting for an underlying random 2D spatial heterogeneity in the diffusion model parameters. A comparison of the magnitude of the boundary-distance effect with the underlying random 2D boundary heterogeneity suggests that both are important sources of variation in the vicinity of the boundary. No consistent pattern emerges from a comparison of the boundary and core spatial heterogeneity, with no indication of a consistently greater level of heterogeneity in one region compared with the other. The results raise the possibility that DWI might provide a surrogate marker of intra-tumour genetic regional heterogeneity, which would provide a powerful tool with applications in both patient management and in cancer research.
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38

Mebarki, Lahcene, Mosbah Zidani, Said Mechachti, Hichem Farh, and Djamel Miroud. "Effect of Nickel Addition Study on the Mechanical Properties of the (Fe3C-Ni) Alloy Obtained by Solid Phase Compaction and Sintering." International Journal of Engineering Research in Africa 32 (September 2017): 18–24. http://dx.doi.org/10.4028/www.scientific.net/jera.32.18.

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The present work aims at determining the effects of Nickel addition on the phase’s distribution in sintered part. It aims equally at identifying the effect of such addition on the microstructure and the mechanical properties. The addition to mixtures of alloying elements in their primitive form can lead to the formation of a heterogeneous microstructure in the sintered parts produced by the powder metallurgy (PM) process. It has been proved that the addition of nickel to an iron powder mixture forms nickel-rich areas (NRA) in the sintered parts. This is basically related to the low diffusion rate of nickel in iron at conventional sintering temperatures.
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39

Brunner, Nina A., Dietmar A. Lang, Matthias Wilmanns, and Reinhard Hensel. "Crystallization and preliminary X-ray diffraction analysis of the NAD-dependent non-phosphorylating GAPDH of the hyperthermophilic archaeon Thermoproteus tenax." Acta Crystallographica Section D Biological Crystallography 56, no. 1 (January 1, 2000): 89–91. http://dx.doi.org/10.1107/s0907444999014134.

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Recombinant non-phosphorylating NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN) of the hyperthermophilic crenarchaeote Thermoproteus tenax has been overexpressed, purified and crystallized using the hanging-drop vapour-diffusion technique. Crystals of different habits were obtained from several precipitant solutions (salts and polyethylene glycols). Preliminary X-ray analysis was performed with crystals grown in ammonium formate, which belonged to the primitive hexagonal space group P622, and had unit-cell parameters a = b = 184.8, c = 133.0 Å, γ = 120°. Assuming a molecular weight of 55 kDa, a Matthews parameter of 3.3 Å3 Da−1 is calculated assuming two molecules per asymmetric unit. The diffraction limit of these crystals is 2.5 Å resolution.
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40

Zhu, Zhen, Miao He, Chun-Hsiang Huang, Tzu-Ping Ko, Yi-Fang Zeng, Yu-Ning Huang, Shiru Jia, Fuping Lu, Je-Ruei Liu, and Rey-Ting Guo. "Crystallization and preliminary X-ray diffraction analysis of a novel β-L-arabinofuranosidase (HypBA1) fromBifidobacterium longum." Acta Crystallographica Section F Structural Biology Communications 70, no. 5 (April 17, 2014): 636–38. http://dx.doi.org/10.1107/s2053230x14001812.

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The β-L-arabinofuranosidase (HypBA1) fromBifidobacterium longumJCM 1217 hydrolyzes the β-1,2-linked arabinofuranose disaccharide to release L-arabinoses. HypBA1 was classified into glycoside hydrolase family 127 (GH127) by the CAZy website (http://www.cazy.org/). The enzyme was expressed inEscherichia coliand the purified recombinant protein was crystallized. Crystals belonging to the primitive hexagonal space groupP3x21, with unit-cell parametersa=b= 75.9,c= 254.0 Å, were obtained by the sitting-drop vapour-diffusion method and diffracted to 2.78 Å resolution. ABLASTPsearch (http://blast.ncbi.nlm.nih.gov/) of the Protein Data Bank did not reveal any similar crystal structures. Structural determination by using SeMet MAD and MIR methods is in progress.
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41

Celik, Ismail, and Gusheng Hu. "Single Grid Error Estimation Using Error Transport Equation." Journal of Fluids Engineering 126, no. 5 (September 1, 2004): 778–90. http://dx.doi.org/10.1115/1.1792254.

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This paper presents an approach to quantify the discretization error as well as other errors related to mesh size using the error transport equation (ETE) technique on a single grid computation. The goal is to develop a generalized algorithm that can be used in conjunction with computational fluid dynamics (CFD) codes to quantify the discretization error in a selected process variable. The focus is on applications where the conservation equations are solved for primitive variables, such as velocity, temperature and concentration, using finite difference and/or finite volume methods. An error transport equation (ETE) is formulated. A generalized source term for the ETE is proposed based on the Taylor series expansion and accessible influence coefficients in the discretized equation. Representative examples, i.e., one-dimensional convection diffusion equation, two-dimensional Poisson equation, two-dimensional convection diffusion equation, and non-linear one-dimensional Burger’s equation are presented to verify this method and elucidate its properties. Discussions are provided to address the significance and possible potential applications of this method to Navier-Stokes solvers.
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42

Hadfield, Andrea T., Greg Petsko, Paul Lindo, and Bal-Ram Singh. "Preliminary crystallographic studies of a protease-resistant botulinum neurotoxin associated protein Hn-33." Acta Crystallographica Section D Biological Crystallography 55, no. 6 (June 1, 1999): 1237–39. http://dx.doi.org/10.1107/s0907444999004771.

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Botulinum neurotoxin (BoNT) is one of the most potent toxins known. BoNT is also a food poison, which means that the toxin must survive the protease action and acidity of the gut. A group of neurotoxin-associated proteins which are only beginning to be identified and characterized are believed to be responsible for this protection. Hn-33 is a 33 kDa polypeptide which is a major component of the type A botulinum neurotoxin complex. Crystals of Hn-33 have been grown by vapour-diffusion techniques. They belong to a primitive orthorhombic space group and diffract to a resolution of 2.6 Å, with unit-cell parameters a = 130.3, b = 122.2, c = 37.2 Å.
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Josts, Inokentijs, Rhys Grinter, Sharon M. Kelly, Khedidja Mosbahi, Aleksander Roszak, Richard Cogdell, Brian O. Smith, Olwyn Byron, and Daniel Walker. "Recombinant expression, purification, crystallization and preliminary X-ray diffraction analysis of the C-terminal DUF490963–1138domain of TamB fromEscherichia coli." Acta Crystallographica Section F Structural Biology Communications 70, no. 9 (August 27, 2014): 1272–75. http://dx.doi.org/10.1107/s2053230x14017403.

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TamB is a recently described inner membrane protein that, together with its partner protein TamA, is required for the efficient secretion of a subset of autotransporter proteins in Gram-negative bacteria. In this study, the C-terminal DUF490963–1138domain of TamB was overexpressed inEscherichia coliK-12, purified and crystallized using the sitting-drop vapour-diffusion method. The crystals belonged to the primitive trigonal space groupP3121, with unit-cell parametersa=b= 57.34,c= 220.74 Å, and diffracted to 2.1 Å resolution. Preliminary secondary-structure and X-ray diffraction analyses are reported. Two molecules are predicted to be present in the asymmetric unit. Experimental phasing using selenomethionine-labelled protein will be undertaken in the future.
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Sviridova, Ekaterina, Ladislav Bumba, Pavlina Rezacova, Katerina Prochazkova, Daniel Kavan, Karel Bezouska, Michal Kuty, Peter Sebo, and Ivana Kuta Smatanova. "Crystallization and preliminary crystallographic characterization of the iron-regulated outer membrane lipoprotein FrpD fromNeisseria meningitidis." Acta Crystallographica Section F Structural Biology and Crystallization Communications 66, no. 9 (August 28, 2010): 1119–23. http://dx.doi.org/10.1107/s174430911003215x.

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Fe-regulated protein D (FrpD) is aNeisseria meningitidisouter membrane lipoprotein that may be involved in the anchoring of the secreted repeat in toxins (RTX) protein FrpC to the outer bacterial membrane. However, the function and biological roles of the FrpD and FrpC proteins remain unknown. Native and selenomethionine-substituted variants of recombinant FrpD43–271protein were crystallized using the sitting-drop vapour-diffusion method. Diffraction data were collected to a resolution of 2.25 Å for native FrpD43–271protein and to a resolution of 2.00 Å for selenomethionine-substituted FrpD43–271(SeMet FrpD43–271) protein. The crystals of native FrpD43–271protein belonged to the hexagonal space groupP62orP64, while the crystals of SeMet FrpD43–271protein belonged to the primitive orthorhombic space groupP212121.
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45

Zamotin, M. P. "Music as a Research Object of Cultural Anthropology by George Herzog." Discourse 6, no. 1 (March 5, 2020): 49–61. http://dx.doi.org/10.32603/2412-8562-2020-6-1-49-61.

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Introduction. Being a universal art form, music in cultural anthropology was understood as a key element of human life throughout the world, represented in a variety of genres, ways of processing sounds, creating harmony, creating song folklore that reflects all aspects of human life. Ethnomusicology, as a unique research field, combined an interest in music both in the form of art and in its sociocultural context. This paper is devoted to the research activity of J. Herzog, thanks to whose efforts the study of folk “primitive” music went beyond musicology and diversified the subject area of cultural anthropology. The relevance of this study is due to the fact that the name of Herzog and his views are not well known in Russia, except for specialized areas of ethnographic and musicological nature.Methodology and sources. As a methodological basis, a comparative historical methodology and a structural-functional method are used to study scientific texts and subsequent processing and generalization of the theoretical constructs of G. Herzog. A biographical method wasused as well to understand the context of time and reveal the scientist’s intellectual genesis.Results and discussion. One of the pioneers in the field of ethnomusicology, G. Herzog used transcription methods and sound analysis in combination with theories and methods of the Boas school, which included the concept of diffusion and the method of field work. Interdisciplinary cooperation in the study of primitive and folk music was an important step for the researcher, since this approach brought the study of folk music to a new level of conceptualization. Herzog was interested in explaining and classifying primitive music and songs in terms of the “root” terms and concepts used by his informants.Conclusion. The interdisciplinary approach in the use of methods for fixing and interpreting musical material in ethnomusicological research by G. Herzog made it possible to overcome the evolutionary linear methodology of studying the musical culture of primitive peoples and draw attention to the context of performance and performers.
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46

Jansen, Malte, and Raffaele Ferrari. "The Vertical Structure of the Eddy Diffusivity and the Equilibration of the Extratropical Atmosphere." Journal of the Atmospheric Sciences 70, no. 5 (April 23, 2013): 1456–69. http://dx.doi.org/10.1175/jas-d-12-086.1.

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Abstract Observations suggest that the time- and zonal-mean state of the extratropical atmosphere adjusts itself such that the so-called “criticality parameter” (which relates the vertical stratification to the horizontal temperature gradient) is close to one. T. Schneider has argued that the criticality parameter is kept near one by a constraint on the zonal momentum budget in primitive equations. The constraint relies on a diffusive closure for the eddy flux of potential vorticity (PV) with an eddy diffusivity that is approximately constant in the vertical. The diffusive closure for the eddy PV flux, however, depends crucially on the definition of averages along isentropes that intersect the surface. It is argued that the definition favored by Schneider results in eddy PV fluxes whose physical interpretation is unclear and that do not satisfy the proposed closure in numerical simulations. An alternative definition, first proposed by T.-Y. Koh and R. A. Plumb, is preferred. A diffusive closure for the eddy PV flux under this definition is supported by analysis of the PV variance budget and can be used to close the near-surface zonal momentum budget in idealized numerical simulations. Following this approach, it is shown that O(1) criticalities are obtained if the eddy diffusivity decays from its surface value to about zero over the depth of the troposphere, which is likely to be the case in Earth’s atmosphere. Large criticality parameters, however, are possible if the eddy diffusivity decays only weakly in the vertical, consistent with results from quasigeostrophic models. This provides theoretical support for recent numerical studies that have found supercritical mean states in primitive equation models.
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47

Sood, Raman, and Paul Liu. "Novel Insights into the Genetic Controls of Primitive and Definitive Hematopoiesis from Zebrafish Models." Advances in Hematology 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/830703.

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Hematopoiesis is a dynamic process where initiation and maintenance of hematopoietic stem cells, as well as their differentiation into erythroid, myeloid and lymphoid lineages, are tightly regulated by a network of transcription factors. Understanding the genetic controls of hematopoiesis is crucial as perturbations in hematopoiesis lead to diseases such as anemia, thrombocytopenia, or cancers, including leukemias and lymphomas. Animal models, particularly conventional and conditional knockout mice, have played major roles in our understanding of the genetic controls of hematopoiesis. However, knockout mice for most of the hematopoietic transcription factors are embryonic lethal, thus precluding the analysis of their roles during the transition from embryonic to adult hematopoiesis. Zebrafish are an ideal model organism to determine the function of a gene during embryonic-to-adult transition of hematopoiesis since bloodless zebrafish embryos can develop normally into early larval stage by obtaining oxygen through diffusion. In this review, we discuss the current status of the ontogeny and regulation of hematopoiesis in zebrafish. By providing specific examples of zebrafish morphants and mutants, we have highlighted the contributions of the zebrafish model to our overall understanding of the roles of transcription factors in regulation of primitive and definitive hematopoiesis.
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48

Wang, Yanting, Shanshan Liu, Pengfei Yao, Yi Yu, Yan Zhang, Wenxian Lan, Chunxi Wang, Jiuping Ding, Wen Liu, and Chunyang Cao. "Crystallographic analysis of NosA, which catalyzes terminal amide formation in the biosynthesis of nosiheptide." Acta Crystallographica Section F Structural Biology Communications 71, no. 8 (July 28, 2015): 1033–37. http://dx.doi.org/10.1107/s2053230x15011085.

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Nosiheptide is a member of the thiopeptide family of antibiotics which demonstrates potent activities against various bacterial pathogens. The formation of its C-terminal amide is catalysed by NosA in an unusual strategy for maturating certain thiopeptides by processing precursor peptides featuring a serine extension. Here, a recombinant C-terminally truncated selenomethionine-derivatized NosA1–111variant fromStreptomyces actuosusconsisting of residues 1–111, named SeMet NosA1–111, was crystallized using the sitting-drop vapour-diffusion method. Diffraction data were collected to 2.40 Å resolution using synchrotron radiation. The crystals belonged to the primitive cubic space groupP4132, with unit-cell parametersa=b=c= 143.3 Å. Assuming the presence of three molecules in the asymmetric unit, the calculated Matthews coefficient was 3.94 Å3 Da−1and the corresponding solvent content was 40.3%.
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49

Tanner, Neta, and Gali Prag. "Purification and crystallization of yeast Ent1 ENTH domain." Acta Crystallographica Section F Structural Biology and Crystallization Communications 68, no. 7 (June 28, 2012): 820–23. http://dx.doi.org/10.1107/s1744309112022488.

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Members of the Epsin protein family regulate the ubiquitin/clathrin-dependent trafficking of transmembrane proteins. The yeast Epsin-1 (ent1) gene was cloned and expressed inEscherichia coli. The protein product of a construct containing the ENTH-UIM modules was purified to homogeneity and subjected to crystallization screening using the sitting-drop vapour-diffusion method. Refined conditions containing polyethylene glycol 3350 and Tacsimate yielded thin rod-like crystals. X-ray analysis revealed that the crystallographic symmetry is primitive orthorhombic, space groupP222, with unit-cell parametersa= 32.7,b= 35.5,c= 110.6 Å and a diffraction limit of 2.3 Å. Matthews coefficient calculations suggested that the crystal contained only the ENTH domain. This was corroborated by Coomassie Blue-stained SDS–PAGE analysis of dissolved crystals.
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50

Jaimohan, S. M., M. D. Naresh, and A. B. Mandal. "Purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies of catfish (Clarias magur) haemoglobin." Acta Crystallographica Section F Structural Biology and Crystallization Communications 68, no. 11 (October 30, 2012): 1371–73. http://dx.doi.org/10.1107/s1744309112040547.

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Haemoglobin is an interesting physiologically significant protein composed of specific functional prosthetic haem and globin moieties. In recent decades, there has been substantial interest in attempting to understand the structural basis and functional diversity of fish haemoglobins (Hbs). Towards this end, purification, crystallization, preliminary X-ray diffraction and molecular-replacement studies have been carried out onClarias magurHb. Crystals were grown by the hanging-drop vapour-diffusion method using PEG 2000 and NaCl as precipitants. The crystals belonged to the primitive monoclinic systemP2, with unit-cell parametersa= 98.35,b= 56.63,c= 112.88 Å, β = 100.22°; a complete data set was collected to a resolution of 2.4 Å. The Matthews coefficient of 2.42 Å3 Da−1for the crystal indicated the presence of two α2β2tetramers in the asymmetric unit.
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