Tensor perturbations from bounce inflation scenario in f(Q)gravity

In this paper,we construct a bounce inflation cosmological scenario in the framework of the modified symmetric teleparallel gravity,namely f(Q)theory,and investigate the tensor perturbations therein.As is well-known,the tensor perturbations generated in the very early Universe(inflation and pre-inflation regions)can account for the primordial gravitational waves(PGWs)that are to be detected by the next generation of GW experiments.We discuss the stability condition of the tensor perturbations in the bounce inflation process and investigate in detail the evolution of the perturbation variable.The general form of the tensor power spectrum is obtained both for large as well as small scale modes.As a result,we show both kinds of modes(short or long wavelength modes),and the tensor spectrum may get a positive tilt in the parametric range where the tensor perturbation proves to be stable—this interestingly hints an enhancement of gravitational waves’amplitude in the background of the f(Q)bounce-inflation scenario.Moreover,we study the LQC-like scenario as a specific case of our model,in which,the primordial tensor power spectrum turns out to be nearly scale-invariant on both small and large scales.

Environmental Arsenic and Selenium Contamination and Approaches Towards Its Bioremediation Through the Exploration of Microbial Adaptations:A Review

Bioaccumulation of selenium and arsenic resulting from geogenic activities and aggravated by anthropogenic actions has now become a serious environmental issue. Different parts of the world are experiencing issues of selenium and arsenic contamination, especially in soil and ground water. The present selenium and arsenic contamination scenario has been well represented in contemporary literature, and there are an array of remediation techniques targeting the decontamination of environmental contamination. The use of microbe-mediated remediation of selenium and arsenic contamination is gaining scientific attention for sustainable environmental bioremediation. The present review elucidates the different aspects of selenium and arsenic contamination, bioaccumulation, and bioremediation with implications for successful decontamination of these heavy metals.

Arsenic Bioremediation Potential of Arsenite-Oxidizing Micrococcus sp. KUMAs15 Isolated from Contaminated Soil

Environmental arsenic(As) contamination,considered as the largest mass poisoning of the human population,has become a serious health concern for the people of South East Asia,including those living in the Bengal delta.An As-resistant strain,KUMAs15,was isolated from the As-contaminated fields in Nadia Ddistrict in West Bengal,India and was evaluated for its possible use in environmental As bioremediation.Molecular identification based on 16S rDNA gene sequencing revealed that the strain belonged to the genus Micrococcus.The strain tolerated high levels of As and oxidized arsenite under the culture condition.The strain also accumulated large quantities of As when exposed to a wide range of environmentally relevant concentrations of inorganic As.Analysis of the aoxB,arsB,and arsC gene expression explained the underlying cause of arsenite oxidation and As accumulation by KUMAs15.The As-resistant strain KUMAs15 of Micrococcus sp.was suggested to be a potential environmental As decontaminant.