Indian plate segmentation along the Himalayan arc: A multi-proxy approach

The underthrusting Indian plate beneath the Himalaya is considered to be segmented along its arc which is manifested in terms of variations in the angle of underthrusting of the Indian mantle lithosphere (IML) and its northern limit beneath Tibet. The pre-existing transverse ridges in the Ganga foreland basin have also been related to these segmentation boundaries. These segmentations imply a change in the mechanical properties of adjoining blocks which should manifest in the form of spatial variations in the topography build-up and other related parameters. We have analyzed the normalized river channel steepness index (ksn) for the entire Himalaya in conjunction with the northern extent of the IML, width of the Ganga foreland basin, and Bouguer gravity anomaly of the orogen to identify its possible correlation with the lithospheric segments and their boundaries. The results reveal spatial variability in the ksn along the arc linked to the segmentation of the Indian plate. The study suggests six distinct sectors in the Himalaya, similar to the ones delineated based on correlation between the width of the Ganga foreland basin and disposition of major Himalayan thrusts. Major offsets in the pockets of the high ksn from the arc-parallel distribution are related to the transverse tectonic fabric of the Indian plate in the Ganga-Brahmaputra plains. Integration of these results support mechanically strong Indian lithosphere for the Kashmir-Himachal sector and the eastern part of the Arunachal sector and weakest lithosphere for the central-eastern Nepal sector

Insulin resistance in chronic hepatitis B virus infection

Objectives: Chronic hepatitis C virus infection is associated with insulin resistance (IR), and both host and viral factors are important in its development. The association and the predictors of IR in chronic hepatitis B virus (CHBV) infection remain unclear. Methods: A total of 69 CHBV-infected subjects were examined to study the relationship between histological findings and anthropometric and biochemical data, including IR determined by the homeostasis model assessment (HOMA-IR). To assess the influence of CHBV infection on IR independent of any effect of hepatic fibrosis, overweight, or sex we also compared fasting serum insulin, C-peptide, HOMA-IR, HOMA-β (measure of β-cell function) and C-peptide-insulin ratio (to distinguish impaired insulin degradation (low ratio) from insulin hypersecretion (normal ratio)) levels between the subset of 14 male normal weight (body mass index, BMI<23) CHBV patients with stage 0 or 1 hepatic fibrosis and 50 male normal weight healthy controls matched by age and anthropometry (BMI and waist circumference).Results: A total of 31 (44.9%) CHBV-infected patients were overweight (BMI>23 kg/m2) and 18 (26.1%) were obese (BMI>25 kg/m2). IR was seen in 34 (49.3%) patients. BMI (Spearman's coefficient=-0.436; P<0.001) and serum triglyceride levels (Spearman's coefficient=-0.307; P=0.010) were univariate predictors of IR. In multiple linear regression analysis, only BMI (P<0.001) was an independent predictor of HOMA-IR. The subgroup of CHBV-infected patients and the controls had comparable levels of all markers of IR, including fasting glucose, insulin, C-peptide, and HOMA-IR. Conclusions: IR in CHBV-infected patients is a reflection of the host metabolic profile and CHBV infection is not in itself correlated with IR