Transformation, partitioning and flow–deposit interactions during the run-out of megaflows

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Bed-thickness and grain-size trends in a small-scale proglacial channel-levée system; the Carboniferous Jejenes Formation, Western Argentina: Implications for turbidity current flow processes

Preserved in Quebrada de las Lajas, near San Juan, Argentina, is an ancient subaqueous proglacial sedimentary succession that includes a small-scale (ca 50 m thick and ca 200 m wide) channel–levee system with excellent exposure of the channel axis and levee sediments. Coeval deposition of both the channel axis and the levees can be demonstrated clearly by lateral correlation of individual beds. The channel axis consists predominantly of a disorganized, pebble to boulder conglomerate with a poorly sorted matrix. The channel axis varies from 10 to 20 m wide and has a total amalgamated thickness of around 50 m. Beds fine gradationally away from the cobble–boulder conglomerates of the channel axis within a few metres, transitioning to well-organized pebble to cobble conglomerates and sandstones of the channel margin. Within 60 m outboard of the channel axis in both directions, perpendicular to the trend of the channel axis, the mean grain size of the beds in the levees is silt to fine-grained sand. Deposits in this channel–levee system are the product of both debris flows (channel axis) and co-genetic turbidity currents (channel margins and levees). Bed thicknesses in the levees increase for up to 10 to 25 m away from the channel axis, beyond which bed thicknesses decrease with increasing distance. The positions of the bed thickness maxima define the levee crests, and the thinning beds constitute the outer levee slopes. From these relationships it is clear that the levee crest migrated both away from and toward the channel axis, and varied in height above the channel axis from 4 to 5 m (undecompacted), whereas the height of the levee crest relative to the distal levee varied from 4.5 to 10 m, indicating that the channel was at times super-elevated relative to the distal levee. Bed thickness decay on the outside of the levee crest can be described quite well with a power-law function (R2=0.85), whereas the thickness decay from the levee crest toward the channel axis follows a linear function (R2 =0.78). Grain-size changes are quite predictable from the channel margin outward, and follow logarithmic (R2=0.77) or power-law (R2=0.72) decay curves, either of which fit the data quite well. This study demonstrates that, in at least this case: (i) levee thickness trends can be directly related to channel-flow processes; (ii) individual bed thickness changes may control overall levee geometry; and (iii) levee and channel deposits can be coeval.Fil: Dykstra, Mason. Colorado School of Mines; Estados UnidosFil: Kneller, Ben. University of Aberdeen; Reino UnidoFil: Milana, Juan Pablo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Geología "Dr. Emiliano Aparicio"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin

Anomalous versus slowed-down Brownian diffusion in the ligand-binding equilibrium

Measurements of protein motion in living cells and membranes consistently report transient anomalous diffusion (subdiffusion) which converges back to a Brownian motion with reduced diffusion coefficient at long times, after the anomalous diffusion regime. Therefore, slowed-down Brownian motion could be considered the macroscopic limit of transient anomalous diffusion. On the other hand, membranes are also heterogeneous media in which Brownian motion may be locally slowed-down due to variations in lipid composition. Here, we investigate whether both situations lead to a similar behavior for the reversible ligand-binding reaction in 2d. We compare the (long-time) equilibrium properties obtained with transient anomalous diffusion due to obstacle hindrance or power-law distributed residence times (continuous-time random walks) to those obtained with space-dependent slowed-down Brownian motion. Using theoretical arguments and Monte-Carlo simulations, we show that those three scenarios have distinctive effects on the apparent affinity of the reaction. While continuous-time random walks decrease the apparent affinity of the reaction, locally slowed-down Brownian motion and local hinderance by obstacles both improve it. However, only in the case of slowed-down Brownian motion, the affinity is maximal when the slowdown is restricted to a subregion of the available space. Hence, even at long times (equilibrium), these processes are different and exhibit irreconcilable behaviors when the area fraction of reduced mobility changes.Comment: Biophysical Journal (2013

The Credit–Growth Nexus: New Evidence from Developing and Developed Countries

The purpose of this paper is to assess the relationship between credit market development and economic growth for a heterogeneous panel of 20 developing and developed countries with varied growth experiences. The empirical study is based on estimations of generalized method of moments (GMM) and pooled mean group (PMG) on heterogeneous panel data model. Difference GMM estimation indicates that credit market development has a negative effect on economic growth. This result is robust for our full sample and for the subsample of non-OECD countries, but not for the subsample of OECD countries. However, using a PMG model, we provide evidence of a positive impact in the long run between credit market development and economic growth. When considering heterogeneity in the short-run relationship across countries, our findings suggest that the credit–growth relationship is specific across countries, depending on each country-specific legal and macroeconomic environment

The ends of a large RNA molecule are necessarily close

We show on general theoretical grounds that the two ends of single-stranded (ss) RNA molecules (consisting of roughly equal proportions of A, C, G and U) are necessarily close together, largely independent of their length and sequence. This is demonstrated to be a direct consequence of two generic properties of the equilibrium secondary structures, namely that the average proportion of bases in pairs is ∼60% and that the average duplex length is ∼4. Based on mfold and Vienna computations on large numbers of ssRNAs of various lengths (1000–10 000 nt) and sequences (both random and biological), we find that the 5′–3′ distance—defined as the sum of H-bond and covalent (ss) links separating the ends of the RNA chain—is small, averaging 15–20 for each set of viral sequences tested. For random sequences this distance is ∼12, consistent with the theory. We discuss the relevance of these results to evolved sequence complementarity and specific protein binding effects that are known to be important for keeping the two ends of viral and messenger RNAs in close proximity. Finally we speculate on how our conclusions imply indistinguishability in size and shape of equilibrated forms of linear and covalently circularized ssRNA molecules

Квазиклассическое описание излучения электрона в графене

Supplementary Item 12: Tracer isotope data

withdrawn 2017 hrs ehra ecas aphrs solaece expert consensus statement on catheter and surgical ablation of atrial fibrillation

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