Nonlinear magnetotransport in Weyl semimetal

The recent discovery of the quantum nonlinear Hall effect has revived the field of nonlinear transport. Here, we predict magnetic field-induced nonlinear Hall effect in time-reversal symmetric Weyl semimetal. We show that the interplay of the band geometric quantities, such as the Berry curvature, and the magnetic part of the Lorentz force can give rise to finite nonlinear Hall conductivity that is linear in the magnetic field. Such nonlinear Hall conductivity can manifest through nonlinear transport measurement as well as nonlinear optical phenomena like photocurrent and the second harmonic generation.Comment: 10 pages, 1 figure; Revised to correct minor typos and add a few more reference

Intrinsic Third Order Nonlinear Transport Responses

Nonlinear transport phenomena offer an exciting probe into the topology and band geometry of the system. Here, we investigate the intrinsic third-order nonlinear responses, independent of the scattering time, using the density matrix-based quantum kinetic formalism. We predict a new intrinsic third-order response that is dissipative and identify a novel intrinsic contribution to the dissipationless Hall response. We demonstrate that these previously unexplored contributions originate from the band geometric quantities such as the Berry curvature and symplectic connection, which are finite in systems that break time-reversal symmetry. We prescribe the symmetry dictionary for these fundamental transport coefficients and unify our quantum kinetic results with results from semiclassical wave-packet formalism. We illustrate our results in antiferromagnetic monolayer SrMnBi$_2$. Our study significantly advances the fundamental understanding of third-order responses.Comment: 14 pages, 3 figures, Comments are welcom

Identification of insertion hot spots for non-LTR retrotransposons: computational and biochemical application to entamoeba histolytica

The genome of the human pathogen Entamoeba histolytica contains non-long terminal repeat (LTR) retrotransposons, the EhLINEs and EhSINEs, which lack targeted insertion. We investigated the importance of local DNA structure, and sequence preference of the element-encoded endonuclease (EN) in selecting target sites for retrotransposon insertion. Pre-insertion loci were tested computationally to detect unique features based on DNA structure, thermodynamic considerations and protein interaction measures. Target sites could readily be distinguished from other genomic sites based on these criteria. The contribution of the EhLINE1-encoded EN in target site selection was investigated biochemically. The sequence-specificity of the EN was tested in vitro with a variety of mutated substrates. It was possible to assign a consensus sequence, 5'-GCATT-3', which was efficiently nicked between A-T and T-T. The upstream G residue enhanced EN activity, possibly serving to limit retrotransposition in the A+T-rich E.histolytica genome. Mutated substrates with poor EN activity showed structural differences compared with normal substrates. Analysis of retrotransposon insertion sites from a variety of organisms showed that, in general, regions of favorable DNA structure were recognized for retrotransposition. A combination of favorable DNA structure and preferred EN nicking sequence in the vicinity of this structure may determine the genomic hotspots for retrotransposition

First report of leucism for the kraits Bungarus walli Wall, 1907 and B. niger Wall, 1908, with updates on their geographic distribution in Nepal (Serpentes, Elapidae)

© 2020 The Authors. Published by Societas Europaea Herpetologica in Herpetology Notes. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://www.biotaxa.org/hn/article/view/62989Six species of kraits, genus Bungarus, have been recorded in Nepal (e.g., Schleich and Kästle, 2002; Sharma et al., 2013), including B. bungaroides (Cantor, 1839), B. caeruleus (Schneider, 1801), B. fasciatus (Schneider, 1801), B. lividus Cantor, 1839, B. niger Wall, 1908, and B. walli Wall, 1907. These species occur from the lowland habitats of the Terai Plains along the Nepal-India border into habitats at intermediate elevations in the Siwalik Hills and into the Mahabharat Range (Joshi et al., 2019), extending in the case of B. caeruleus, the most commonly encountered krait in Nepal, up to elevations of at least 1525 m, and up to 1730 m in B. bungaroides (Schleich and Kästle, 2002; Sharma et al., 2013). All of these species appear to be of medical importance as a cause of snakebite mortality and morbidity (e.g., Bhetwal et al., 1998; Pandey, 2015). It is noteworthy that confirmed records of kraits in Nepal display a patchiness consistent with intermittent sampling: while some species probably have a countrywide distribution, records tend to exist primarily for areas of high human population concentration where sampling and the incidence of snakebite can be expected at greater frequency (e.g., B. caeruleus, B. fasciatus, B. lividus). On the other hand, some species cluster only in the southeasternmost extreme of the country (B. bungaroides, B. walli), and given their distribution in neighbouring countries, this sampling may reflect reality

Save The King: Human-King Cobra, Ophiophagus hannah (Cantor 1836), conflicts and the need for conservation strategies in Nepal

Abstract.—Snake research tends to have a low priority in Nepal and very little information, mostly confined to populationsin small areas, addresses the biology and threats to the King Cobra (Ophiophagus hannah). Herein we providedata that could facilitate an assessment of the species’ status in Nepal and begin to address its conservation needs.We recorded data on King Cobras from 2015–2020, crosschecking with previous studies to avoid any duplicationof records. A King Cobra from Siddhara, Arghakhachi District, was the first record of the species in the district. Werecorded a total of 50 King Cobra mortalities from 20 districts, with most of them killed near human settlementsadjacent to forested areas. We mapped the locations of all mortalities and recorded land-use changes within a 500-mbuffer around each site over a 30-year period (1990–2020), revealing extensive landscape fragmentation in previouslyconnected natural areas. Our data suggest that the major threats to King Cobras are deliberate killing by humans andlarge-scale habitat loss due to an increasing human population. We recommend increased research to better understandthe biology of this charismatic species and continued conservation education and community outreach programs tofacilitate the development of effective conservation strategies

Painful vertical diplopia as a presentation of a pituitary mass

BACKGROUND: Pituitary tumours may present with a variety of neurological and endocrinological signs and symptoms. It is very rare however for them to present with sudden onset painful diplopia. The current literature and possible mechanisms for this are discussed. CASE PRESENTATION: We describe a case of a pituitary mass which presented with sudden onset painful diplopia with an associated restricted pattern on Lees Chart testing. This led to an initial working diagnosis of orbital myositis. CONCLUSION: Awareness of different modes of presentation of pituitary lesions is important so that appropriate imaging may be requested and delay in diagnosis prevented

An integrated transcriptomics-guided genome-wide promoter analysis and next-generation proteomics approach to mine factor(s) regulating cellular differentiation

Differential next-generation-omics approaches aid in the visualization of biological processes and pave the way for divulging important events and/or interactions leading to a functional output at cellular or systems level. To this end, we undertook an integrated Nextgen transcriptomics and proteomics approach to divulge differential gene expression of infant and pubertal rat Sertoli cells (Sc).Unlike, pubertal Sc, infant Sc are immature and fail to support spermatogenesis. We found exclusive association of 14 and 19 transcription factor binding sites to infantile and pubertal states of Sc, respectively, using differential transcriptomics-guided genome-wide computational analysis of relevant promoters employing 220 Positional Weight Matrices from the TRANSFAC database. Proteomic SWATH-MS analysis provided extensive quantification of nuclear and cytoplasmic protein fractions revealing 1,670 proteins differentially located between the nucleus and cytoplasm of infant Sc and 890 proteins differentially located within those of pubertal Sc. Based on our multi-omics approach, the transcription factor YY1 was identified as one of the lead candidates regulating differentiation of Sc.YY1 was found to have abundant binding sites on promoters of genes upregulated during puberty. To determine its significance, we generated transgenic rats with Sc specific knockdown of YY1 that led to compromised spermatogenesis

An integrated transcriptomics-guided genome-wide promoter analysis and next-generation proteomics approach to mine factor(s) regulating cellular differentiation.

Differential next-generation-omics approaches aid in the visualization of biological processes and pave the way for divulging important events and/or interactions leading to a functional output at cellular or systems level. To this end, we undertook an integrated Nextgen transcriptomics and proteomics approach to divulge differential gene expression of infant and pubertal rat Sertoli cells (Sc).Unlike, pubertal Sc, infant Sc are immature and fail to support spermatogenesis. We found exclusive association of 14 and 19 transcription factor binding sites to infantile and pubertal states of Sc, respectively, using differential transcriptomics-guided genome-wide computational analysis of relevant promoters employing 220 Positional Weight Matrices from the TRANSFAC database. Proteomic SWATH-MS analysis provided extensive quantification of nuclear and cytoplasmic protein fractions revealing 1,670 proteins differentially located between the nucleus and cytoplasm of infant Sc and 890 proteins differentially located within those of pubertal Sc. Based on our multi-omics approach, the transcription factor YY1 was identified as one of the lead candidates regulating differentiation of Sc.YY1 was found to have abundant binding sites on promoters of genes upregulated during puberty. To determine its significance, we generated transgenic rats with Sc specific knockdown of YY1 that led to compromised spermatogenesis