Cholesterol-dependent cytolysins (CDCs) are protein toxins that originate from Gram-positive bacteria and contribute substantially to their pathogenicity. CDCs bind membrane cholesterol and build prepores and lytic pores. Some effects of the toxins are observed in non-lytic concentrations. Two pathogens, Streptococcus pneumoniae and Listeria monocytogenes, cause fatal bacterial meningitis, and ...

Why do societies collapse? We use an individual-based evolutionary model to show that, in environmental conditions dominated by low-frequency variation (“red noise”), extirpation may be an outcome of the evolution of cultural capacity. Previous analytical models predicted an equilibrium between individual learners and social learners, or a contingent strategy in which individuals learn socially...

The Shaker B K(+) conductance (G(K)) collapses when the channels are closed (deactivated) in Na(+) solutions that lack K(+) ions. Also, it is known that external TEA (TEA(o)) impedes the collapse of G(K), and that channel block by TEA(o) and scorpion toxins are two mutually exclusive events. Therefore, we tested the ability of scorpion toxins to inhibit the collapse of G(K) in 0 K(+). We have f...

Environmental determinism is often used to explain past social collapses and predict the future of modern human societies. We assess availability natural resources resulting carrying capacity (a basic concept environmental determinism) through a toy model based on Hurst–Kolmogorov dynamics. also highlight role cohesion, we evaluate it from an entropic viewpoint. Furthermore, make case that, whe...

Progressive collapse is defined as the spread of an initial damage from one member to another, leading to extensive partial or total collapse of the structure. In this research, the potential of progressive collapse due to a sudden removal of vertical load-bearing elements in reinforced concrete buildings structures with different floor plans such as geometrical regular and irregular floor plan...

Estimation of collapse performance is primarily conducted through Collapse Fragility Curves (CFC’s). The EDP-based approach is the main scheme for attaining such curves and employs IDA. Obtaining CFC’s from IDA results is tremendously time consuming and computationally demanding. Introduction of more efficient methods of seismic analysis, can potentially improve this issue. The Endurance Time (...

in the first impounding of rockfill dams, additional settlements occur in upstream side in saturated rockfills due to collapse phenomenon even high rainy seasons can cause additional deformation in the dumped rockfills. unfortunately these displacements are not taken into account in the conventional numerical models which are currently used to predict embankment dam behavior during impounding. ...

The damming of a river causes dangerous consequences on structure of the environment downstream of the dam, modifying the sediment composition, which impose major adjustments in longitudinal distribution of benthic community. The construction of Engenheiro Sérgio Motta Dam in the Upper Paraná River has caused impacts on the aquatic communities, which are not yet fully known. This work aimed to ...

Non-leptonic D meson decays may provide a reliable testbed for the multiquark interpretation of light scalar mesons. In this letter we consider D s decay and show that a 4-quark f 0 (980) meson could induce a decay pattern, which is forbidden for a q ¯ q constituent structure. Experimental tests to probe such possibilities are within reach in the near future.