Influence of Fines Content on Liquefaction from a Critical State Framework: the Christchurch Earthquake Case Study

In earthquake engineering practice, the liquefaction potential of soils is commonly evaluated through simplified procedures. These approaches are suitable for sands with very low to no fines content, which have been traditionally thought to be the only liquefiable materials. However, field observations and experimental research have extensively demonstrated that low plasticity silty sands can also be highly liquefiable. Thus, this paper investigates the effect of nonplastic fines contents on the liquefaction potential of soils, taking the 2010–2011 Canterbury Earthquake Sequence as a case study. The validity of standard simplified procedures for high fines content soils is critically evaluated and compared with a finite element model based on a full solid–fluid coupled formulation. The model includes a state parameter-based constitutive law within the generalised plasticity theory, which allows the fines content to be taken into account explicitly. The standard simplified procedures are shown to be less effective in the evaluation of liquefaction potential in soils with high fines content but are still indispensable tools for evaluating the performance of soils over large urban areas. As the main conclusion, it is recommended that empirical models are complemented with an advanced numerical analysis in those cases where silty sands with high fines content are identified, as its outcomes can more realistically represent the soil behaviour during a seismic event

Detailed ground study of 8 - 13 micron infrared imagery, Carrizo Plains, California

Infrared imagery study to determine dark thermal anomalies associated with San Andreas fault trac

A numerical approach for liquefaction potential definition

Liquefaction phenomenon in saturated granular soil is not that frequent as amplification cases but can cause heavy damages on buildings and infrastructures whenever is occurs especially within superficial strata. In fact the lack of shear resistance of soil due to liquefaction affects mostly shallow foundations and road surfaces. Up now, several studies have been addressed to overpass the inadequacy of liquefaction safety factor by means of introducing the liquefaction potential. Nevertheless, the difficulty in (1) defining a scale of damage related to liquefaction potential values and (2) collecting field data from damages caused prevalently by liquefaction makes the punctual factor of safety still popular in engineering practice. In this paper a new approach to liquefaction potential estimation is proposed based on finite element dynamic analyses and on the concept of “significant volume” according to possible effects suffered by shallow foundations. One-dimensional simulation of liquefaction occurrence is performed by means of the Pastor-Zienkiewicz constitutive law. Hence the estimation of liquefaction potential is gained as well as the stress influence factor from Westergaard solution is calculated

Trace element fractionation between PM10 and PM2.5 in coal mine dust: Implications for occupational respiratory health

This is the final version. Available on open access from Elsevier via the DOI in this recordInvestigations into the respiratory health impacts of coal mine particulate matter (PM) face the challenge of understanding its chemical complexity. This includes highly variable concentrations of trace metals and metalloids such as Fe, Ti, Mn, Zn, Ni, V, Cr, Cu, Pb, Cd, Sb, As and Sn, which may be capable of inducing cell damage. Analysis of PM10 and PM2.5 samples size-separated from deposited coal mine dusts collected on PVC flat surfaces at a height of 1.5-2 m inside the second level in the Velenje lignite mine, Slovenia, demonstrates that some of these metallic elements (in this case Cu, Sb, Sn, Pb, Zn, As, Ni) can be concentrated in PM2.5, the most deeply inhalable and therefore potentially most bioreactive size fraction. These elements are likely to be mainly present in silicates, oxides, and perhaps antimonides and arsenides, rather than in the calcareous, carbonaceous or sulphide components which show no obvious affinity for PM2.5. Whereas in the Velenje lignites concentrations of these metallic elements are low and so do not present any obvious extra health risk to the miners, this is unlikely to be the case in mines where unusually metal-enriched coals are being excavated. We therefore recommend that levels of potentially toxic elements in PM2.5 should be assessed where metal- and metalloid-rich coals are being mined worldwide, especially given uncertainties relating to the efficiency of current dust suppression and respiratory protective equipment for such fine particle sizes.European Commission Research Fund for Coal and Stee

Numerical simulation of observed liquefaction phenomena from the 2011 Christchurch (New Zealand) event

Soil liquefaction at the ground often cause damages to various infrastructure assets. Its consequences have been widely made evident by the performance of the Telecommunication Network Services during the 2010-2011 Canterbury Earthquake Sequence (CES) which stroke the Canterbury region in New Zealand. Despite the relevance of loss of functionality of the telecommunication system, especially during the post-event recovery phase, studies in the literature on the network performance about damages due to liquefaction are still limited. Exploring an unprecedented database of in-situ geotechnical inspections collected after the CES, this research first compares alternative empirical liquefaction-triggering models available in the literature with observation maps. Then, a soil column profile is evaluated adopting a constitutive model based on generalised plasticity (‘modified Pastor-Zienkiewicz’) through a Finite Element based home-developed code. The obtained results from the numerical models are finally crosschecked with the empirical analyses, the existing liquefaction investigation maps and field observations collected in the aftermath of the CES

New insights from zinc and copper isotopic compositions of atmospheric particulate matter from two major European cities

This study reports spatial and temporal variability of Zn and Cu isotopes in atmospheric particulate matter (PM) collected in two major European cities with contrasting atmospheric pollution, Barcelona and London. We demonstrate that non-traditional stable isotopes identify source contributions of Zn and Cu and can play a major role in future air quality studies. In Barcelona, fine PM were collected at street level at sites with variable traffic density. The isotopic signatures ranged between −0.13±0.09 and −0.55±0.09‰ for d66ZnIRMM and between +0.04±0.20 and +0.33±0.15‰ for d65CuAE633. Copper isotope signatures similar to Cu sulphides and Cu/Sb ratios within the range typically found in brake wear suggest that non-exhaust emissions from vehicles are dominant. Negative Zn isotopic signatures characteristic for gaseous emissions from smelting and combustion and large enrichments of Zn and Cd suggest contribution from metallurgical industries. In London, coarse PM collected on the top of a building over 18 months display isotope signatures ranging between +0.03±0.04 and +0.49±0.02‰ for d66ZnIRMM and between +0.37±0.17 and +0.97±0.21‰ for d65CuAE633. Heavy Cu isotope signatures (up to +0.97±0.21‰) and higher enrichments and Cu/Sb ratios during winter time suggest important contribution from fossil fuel combustion. The positive d66ZnIRMM signatures are in good agreement with signatures characteristic for ore concentrates used for the production of tires and galvanised materials, suggesting non-exhaust emissions from vehicles as the main source of Zn

Hydraulic validation of two-dimensional simulations of braided river flow with spatially continuous aDcp data

Gravel‐bed braided rivers are characterized by shallow, branching flow across low relief, complex, and mobile bed topography. These conditions present a major challenge for the application of higher dimensional hydraulic models, the predictions of which are nevertheless vital to inform flood risk and ecosystem management. This paper demonstrates how high‐resolution topographic survey and hydraulic monitoring at a density commensurate with model discretization can be used to advance hydrodynamic simulations in braided rivers. Specifically, we detail applications of the shallow water model, Delft3d, to the Rees River, New Zealand, at two nested scales: a 300 m braid bar unit and a 2.5 km reach. In each case, terrestrial laser scanning was used to parameterize the topographic boundary condition at hitherto unprecedented resolution and accuracy. Dense observations of depth and velocity acquired from a mobile acoustic Doppler current profiler (aDcp), along with low‐altitude aerial photography, were then used to create a data‐rich framework for model calibration and testing at a range of discharges. Calibration focused on the estimation of spatially uniform roughness and horizontal eddy viscosity, νH, through comparison of predictions with distributed hydraulic data. Results revealed strong sensitivity to νH, which influenced cross‐channel velocity and localization of high shear zones. The high‐resolution bed topography partially accounts for form resistance, and the recovered roughness was found to scale by 1.2–1.4 D84 grain diameter. Model performance was good for a range of flows, with minimal bias and tight error distributions, suggesting that acceptable predictions can be achieved with spatially uniform roughness and νH.Field campaigns were primarily funded by NERC Grant NE/G005427/1 and NERC Geophysical Equipment Facility Loan 892 as well as NSERC and CFI (Canada) grants to Colin Rennie. Damia Vericat was supported by a Ramon y Cajal Fellowship (RYC‐2010‐06264) funded by the Spanish Ministry of Science and Innovation during the preparation of this manuscript. Numerical simulations were undertaken during a visit by Richard Williams to NIWA. This visit was funded by the British Hydrology Society and an Aberystwyth University Postgraduate Studentship. Murray Hicks and Richard Measures were funded by NIWA core funding under the Sustainable Water Allocation Programme

Human-like eukaryotic translation initiation factor 3 from Neurospora crassa

Eukaryotic translation initiation factor 3 (eIF3) is a key regulator of translation initiation, but its in vivo assembly and molecular functions remain unclear. Here we show that eIF3 from Neurospora crassa is structurally and compositionally similar to human eIF3. N. crassa eIF3 forms a stable 12-subunit complex linked genetically and biochemically to the 13th subunit, eIF3j, which in humans modulates mRNA start codon selection. Based on N. crassa genetic analysis, most subunits in eIF3 are essential. Subunits that can be deleted (e, h, k and l) map to the right side of the eIF3 complex, suggesting that they may coordinately regulate eIF3 function. Consistent with this model, subunits eIF3k and eIF3l are incorporated into the eIF3 complex as a pair, and their insertion depends on the presence of subunit eIF3h, a key regulator of vertebrate development. Comparisons to other eIF3 complexes suggest that eIF3 assembles around an eIF3a and eIF3c dimer, which may explain the coordinated regulation of human eIF3 levels. Taken together, these results show that Neurospora crassa eIF3 provides a tractable system for probing the structure and function of human-like eIF3 in the context of living cells. © 2013 Smith et al.This work was funded by the NIH (grants R56-AI095687, R01-GM65050, and P50-GM102706 to JHDC; and from the Howard Hughes Medical Institute for JQAPeer Reviewe

Progress toward curing HIV infection with hematopoietic cell transplantation.

HIV-1 infection afflicts more than 35 million people worldwide, according to 2014 estimates from the World Health Organization. For those individuals who have access to antiretroviral therapy, these drugs can effectively suppress, but not cure, HIV-1 infection. Indeed, the only documented case for an HIV/AIDS cure was a patient with HIV-1 and acute myeloid leukemia who received allogeneic hematopoietic cell transplantation (HCT) from a graft that carried the HIV-resistant CCR5-∆32/∆32 mutation. Other attempts to establish a cure for HIV/AIDS using HCT in patients with HIV-1 and malignancy have yielded mixed results, as encouraging evidence for virus eradication in a few cases has been offset by poor clinical outcomes due to the underlying cancer or other complications. Such clinical strategies have relied on HIV-resistant hematopoietic stem and progenitor cells that harbor the natural CCR5-∆32/∆32 mutation or that have been genetically modified for HIV-resistance. Nevertheless, HCT with HIV-resistant cord blood remains a promising option, particularly with inventories of CCR5-∆32/∆32 units or with genetically modified, human leukocyte antigen-matched cord blood

Two RNA-binding motifs in eIF3 direct HCV IRES-dependent translation

The initiation of protein synthesis plays an essential regulatory role in human biology. At the center of the initiation pathway, the 13-subunit eukaryotic translation initiation factor 3 (eIF3) controls access of other initiation factors and mRNA to the ribosome by unknown mechanisms. Using electron microscopy (EM), bioinformatics and biochemical experiments, we identify two highly conserved RNA-binding motifs in eIF3 that direct translation initiation from the hepatitis C virus internal ribosome entry site (HCV IRES) RNA. Mutations in the RNA-binding motif of subunit eIF3a weaken eIF3 binding to the HCV IRES and the 40S ribosomal subunit, thereby suppressing eIF2-dependent recognition of the start codon. Mutations in the eIF3c RNA-binding motif also reduce 40S ribosomal subunit binding to eIF3, and inhibit eIF5B-dependent steps downstream of start codon recognition. These results provide the first connection between the structure of the central translation initiation factor eIF3 and recognition of the HCV genomic RNA start codon, molecular interactions that likely extend to the human transcriptome. © 2013 The Author(s)National Institutes of Health (NIH) [R56-AI095687 to J.H.D.C.; P50-GM102706 to J.A.D. and J.H.D.C.]; Spanish Ministry of Education through the Programa Nacional de Movilidad de Recursos Humanos del Plan Nacional de I-D+i 2008-2011 (to E.A.-P.). J.A.D. and E.N. are Howard Hughes Medical Institute Investigators. Funding for open access charge: NIH [P50-GM102706]Peer Reviewe