Radio light curves during the passage of cloud G2 near Sgr A*

We calculate radio light curves produced by the bow shock that is likely to form in front of the G2 cloud when it penetrates the accretion disk of Sgr A*. The shock acceleration of the radio-emitting electrons is captured self-consistently by means of first-principles particle-in-cell simulations. We show that the radio luminosity is expected to reach maximum in early 2013, roughly a month after the bow shock crosses the orbit pericenter. We estimate the peak radio flux at 1.4 GHz to be 1.4 - 22 Jy depending on the assumed orbit orientation and parameters. We show that the most promising frequencies for radio observations are in the 0.1<nu<1 GHz range, for which the bow shock emission will be much stronger than the intrinsic radio flux for all the models considered.Comment: 15 pages, 10 figures, accepted for publication in MNRA

Root morphology of mandibular molars: a cone-beam computed tomography study

Background: The aim of the study was to assess the number and anatomical classification of roots and root canals of first and second mandibular molars using cone-beam computed tomography (CBCT) in a Chilean population. Materials and methods: This study evaluated the CBCT scans of 289 patients aged between 14 and 86 years, obtaining a sample of 1022 mandibular first and second molars. The number of roots and root canals was evaluated according to the anatomical classification proposed by Ahmed in 2016. Data were analysed using Pearson’s chi-squared test and ANOVA. Results: Nine hundred fifty-one (93.05%) molars had two roots, while the remaining 71 (6.95%) molars had one root. The most frequent root and root canal morphologies found were: 2MM M2 D1 (29.65%),  2MM M2-1 D1 (22.3%) and 2MM M1 D1 (13.4%) (M — mesial, D — distal), with a total of 32 different anatomical distributions. C-shaped canals were present in 56 molars and were more frequently found in women than in men (7.1% vs. 3.88%; p = 0.024). Conclusions: The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals. The most frequent morphology found in mandibular molars in a Chilean population was two roots and three canals

Variable density flow in porous media

We review the state of the art in modeling of variable-density flow and transport in porous media, including conceptual models for convection systems, governing balance equations, phenomenological laws, constitutive relations for fluid density and viscosity, and numerical methods for solving the resulting nonlinear multifield problems. The discussion of numerical methods addresses strategies for solving the coupled spatio-temporal convection process, consistent velocity approximation, and error-based mesh adaptation techniques. As numerical models for those nonlinear systems must be carefully verified in appropriate tests, we discuss weaknesses and inconsistencies of current model-verification methods as well as benchmark solutions. We give examples of field-related applications to illustrate specific challenges of further research, where heterogeneities and large scales are important

Generation and characterization of nucleic acid aptamers targeting the capsid P domain of a human norovirus GII.4 strain

AbstractHuman noroviruses (NoV) are the leading cause of acute viral gastroenteritis worldwide. Significant antigenic diversity of NoV strains has limited the availability of broadly reactive ligands for design of detection assays. The purpose of this work was to produce and characterize single stranded (ss)DNA aptamers with binding specificity to human NoV using an easily produced NoV target—the P domain protein. Aptamer selection was done using SELEX (Systematic Evolution of Ligands by EXponential enrichment) directed against an Escherichia coli-expressed and purified epidemic NoV GII.4 strain P domain. Two of six unique aptamers (designated M1 and M6-2) were chosen for characterization. Inclusivity testing using an enzyme-linked aptamer sorbent assay (ELASA) against a panel of 14 virus-like particles (VLPs) showed these aptamers had broad reactivity and exhibited strong binding to GI.7, GII.2, two GII.4 strains, and GII.7 VLPs. Aptamer M6-2 exhibited at least low to moderate binding to all VLPs tested. Aptamers significantly (p<0.05) bound virus in partially purified GII.4 New Orleans outbreak stool specimens as demonstrated by ELASA and aptamer magnetic capture (AMC) followed by RT-qPCR. This is the first demonstration of human NoV P domain protein as a functional target for the selection of nucleic acid aptamers that specifically bind and broadly recognize diverse human NoV strains