A semi-analytical method for nonlinear vibration of Euler-Bernoulli beams with general boundary conditions

This paper presents a new semianalytical approach for geometrically nonlinear vibration analysis of Euler-Bernoulli beams with different boundary conditions. The method makes use of Linstedt-Poincaré perturbation technique to transform the nonlinear governing equations into a linear differential equation system, whose solutions are then sought through the use of differential quadrature approximation in space domain and an analytical series expansion in time domain. Validation of the present method is conducted in numerical examples through direct comparisons with existing solutions, showing that the proposed semianalytical method has excellent convergence and can give very accurate results at a long time interval

Transcriptional and Functional Studies of a Cd(II)/Pb(II)-Responsive Transcriptional Regulator(CmtR) from Acidithiobacillus ferrooxidans ATCC 23270

The acidophilic Acidithiobacillusferrooxidans can resist exceptionally high cadmium (Cd) concentrations. This property is important for its use in biomining processes, where Cd and other metal levels range usually between 15 and 100 mM. To learn about the mechanisms that allow A. ferrooxidans cells to survive in this environment, a bioinformatic search of its genome showed the presence of that a Cd(II)/Pb(II)-responsive transcriptional regulator (CmtR) was possibly related to Cd homeostasis. The expression of the CmtR was studied by real-time reverse transcriptase PCR using A. ferrooxidans cells adapted for growth in the presence of high concentrations of Cd. The putative A. ferrooxidans Cd resistance determinant was found to be upregulated when this bacterium was exposed to Cd in the range of 15–30 mM. The CmtR from A. ferrooxidans was cloned and expressed in Escherichiacoli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. UV–Vis spectroscopic measurements showed that the reconstruction CmtR was able to bind Cd(II) forming Cd(II)–CmtR complex in vitro. The sequence alignment and molecular modeling showed that the crucial residues for CmtR binding were likely to be Cys77, Cys112, and Cys121. The results reported here strongly suggest that the high resistance of the extremophilic A. ferrooxidans to Cd including the Cd(II)/Pb(II)-responsive transcriptional regulator

Data from: Shorebirds-driven trophic cascade helps restore coastal wetland multifunctionality

<p>Ecosystem restoration has traditionally focused on re-establishing vegetation and other foundation species at basal trophic levels, with mixed outcomes. Here, we show that threatened shorebirds could be important to restoring coastal wetland multifunctionality. We carried out surveys and manipulative field experiments in a region along the Yellow Sea affected by the invasive cordgrass Spartina alterniflora. We found that planting native plants alone failed to restore wetland multifunctionality in a field restoration experiment. Shorebird exclusion weakened wetland multifunctionality, whereas mimicking higher predation before shorebird population declines by excluding their key prey – crab grazers – enhanced wetland multifunctionality. The mechanism underlying these effects is a simple trophic cascade, whereby shorebirds control crab grazers that otherwise suppress native vegetation recovery and destabilize sediments (via bioturbation). Our findings suggest that harnessing the top-down effects of shorebirds – through habitat conservation, rewilding, or temporary simulation of consumptive or non-consumptive effects – should be explored as a nature-based solution to restoring the multifunctionality of degraded coastal wetlands.  </p><p> </p><p>This ZIP file contains the following datasets and code for the above paper:</p><p>1.  Focal study site_shorebird trends.xlsx This file contains data on shorebird abundance at the focal study site between 1996 and 2021</p><p>2.  Regional crab grazing effects.xlsx This file contains data used in the meta-analysis of studies on the effect of crab grazers on native wetland plants</p><p>3.  Regional predation intensity.xlsx This file contains data on shorebird predation on crabs at five native marsh sites</p><p>4.  Restoration experiment_bird abundance.xlsx This file contains data on bird abundance in three camera traps installed at the restoration site</p><p>5.  Restoration experiment_bird species richness.xlsx This file contains data on bird species richness in three camera traps installed at the restoration site</p><p>6.  Restoration experiment_crab abundance.xlsx This file contains data on crab abundance in different treatments of the restoration experiment</p><p>7. Restoration experiment_ecosystem functions.xlsx This file contains data for the 12 ecosystem functions measured in different treatments of the restoration experiment</p><p>8. Restoration experiment_for meta-regression of bird effect sizes on crab abundance This file contains the calculated effect sizes of birds on crab abundance for meta-regression against bird abundance</p><p>9. Restoration experiment_for regression of ecosystem functions This file contains data for regression of ecosystem functions and multifunctionality against crab abundance and primary production  </p><p>10.  Restoration experiment_plant abundance.xlsx This file contains data on plant abundance in different treatments of the restoration experiment</p><p>11.  Restoration experiment_predation intensity.xlsx This file contains data on shorebird predation on tethered crabs in different treatments of the restoration experiment</p><p>12. Restoration experiment_the rate of plant abundance change.xlsx This file contains data on the rate of plant abundance change in different treatments of the restoration experiment  </p><p>13. Shorebird non-consumptive effects experiment.xlsx This file contains data on crab abundance in different treatments of the shorebird non-consumptive effects simulation experiment</p><p>14. Code_Li_Shorebirds_Ms.R This file contains the R code used for data analysis. </p&gt