337 research outputs found
Bearing Capacity of Spatially Random Cohesive Soil Using Numerical Limit Analyses
This paper describes a probabilistic study of the two dimensional bearing capacity of a vertically loaded strip footing on spatially random, cohesive soil using Numerical Limit Analyses (NLA‐CD). The analyses uses a Cholesky Decomposition (CD) technique with mid‐point discretization to represent the spatial variation in undrained shear strength within finite element meshes for both upper and lower bound analyses, and assumes an isotropic correlation length. Monte Carlo simulations are then used to interpret the bearing capacity for selected ranges of the coefficient of variation in undrained shear strength and the ratio of correlation length to footing width. The results are compared directly with data from a very similar study by Griffiths et al. in which bearing capacity realizations were computed using a method of Local Average Subdivision (LAS) in a conventional displacement‐based Finite Element Method (FEM‐LAS). These comparisons show the same qualitative features, but suggest that the published FEM calculations tend to overestimate the probability of failure at large correlation lengths. The NLA method offers a more convenient and computationally efficient approach for evaluating effects of variability in soil strength properties in geotechnical stability calculations
Rainfall-induced differential settlements of foundations on heterogeneous unsaturated soils
This study stochastically investigates the rainfall-induced differential settlement of a centrally loaded, rigid strip foundation on an unsaturated soil with spatially varying values of either preconsolidation stress or porosity. The differential settlement (between the two foundation ends) is calculated at various times during rainfall by way of a coupled, hydro-mechanical, finite-element analysis. The Barcelona basic model describes the mechanical behaviour of the soil, and the van Genuchten relationships describe water retention and permeability. The variability of soil properties is modelled by means of random fields with spatial correlation in the framework of a Monte Carlo simulation. The study demonstrates that the occurrence of rainfall-induced differential settlements can be consistently analysed using concepts of unsaturated soil mechanics and random field theory. Results show that differential settlements can be vastly underpredicted (or even completely missed) if random heterogeneity and partial saturation are not simultaneously considered. The variation of differential settlements and their statistics during the rainfall depend on the magnitude of the applied load and the statistics of soil variability. Moreover, the transient phase of infiltration and a spatial correlation length equal to the width of the foundation pose the highest risk of differential settlement
Attitude and Behavior Effects in a Randomized Trial of Increased Access to Emergency Contraception
To explore the effects of providing unrestricted access to emergency contraception in advance of need on various psychosocial outcomes and pregnancy
Rapamycin Monotherapy in Patients With Type 1 Diabetes Modifies CD4+CD25+FOXP3+ Regulatory T-Cells
OBJECTIVE—Rapamycin is an immunosuppressive drug currently used to prevent graft rejection in humans, which is considered permissive for tolerance induction. Rapamycin allows expansion of both murine and human naturally occurring CD4+CD25+FOXP3+ T regulatory cells (nTregs), which are pivotal for the induction and maintenance of peripheral tolerance. Preclinical murine models have shown that rapamycin enhances nTreg proliferation and regulatory function also in vivo. Objective of this study was to assess whether rapamycin has in vivo effects on human nTregs
The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence
The collapse of a mine tailings dam and subsequent flood in SE Brazil on 5 November 2015 was preceded by a small-magnitude seismic sequence. In this report, we explore the spatiotemporal associations between the seismic events and the accident and discuss their possible connection. We also analyze the signals generated by the turbulent mudflow, as recorded by the Brazilian Seismographic Network (RSBR). In light of our observations, we propose as possible contributing factor for the dam collapse either ground shaking and/or soil liquefaction triggered by the earthquakes. The possibility of such a small-magnitude earthquake contributing to the collapse of a tailings dam raises important concerns regarding safety and related legislation of dams in Brazil and the world. ©2016. American Geophysical Union.H.A.D. and M.A. acknowledge support from Sao Paulo Research Foundation FAPESP grant 2014/09455-3 and CNPq grant 30.6547/2013-9.Peer reviewe
T Regulatory Cells in Cord Blood—FOXP3 Demethylation as Reliable Quantitative Marker
Regulatory T-cells (Tregs), characterized as CD4+CD25(hi) T-cells expressing FOXP3, play a crucial role in controlling healthy immune development during early immune maturation. Recently, FOXP3 demethylation was suggested to be a novel marker for natural Tregs in adults. In cord blood, the role and function of Tregs and its demethylation is poorly understood. We assessed FOXP3 demethylation in cord blood in relation to previously used Treg markers such as CD4+CD25(hi), FOXP3 mRNA, protein expression, and suppressive Treg function
Reliability analysis of idealized tunnel support system using probability-based methods with case studies
Graft-vs-tumor effect in patients with advanced nasopharyngeal cancer treated with nonmyeloablative allogeneic PBSC transplantation
While nonmyeloablative peripheral blood stem cell transplantation (NST) has shown efficacy against several solid tumors, it is untested in nasopharyngeal cancer (NPC). In a phase II clinical trial, 21 patients with pretreated metastatic NPC underwent NST with sibling PBSC allografts, using CY conditioning, thymic irradiation and in vivo T-cell depletion with thymoglobulin. Stable lymphohematopoietic chimerism was achieved in most patients and prophylactic CYA was tapered at a median of day +30. Seven patients (33%) showed partial response and three (14%) achieved stable disease. Four patients were alive at 2 years and three showed prolonged disease control of 344, 525 and 550 days. With a median follow-up of 209 (4–1147) days, the median PFS was 100 days (95% confidence interval (CI), 66–128 days), and median OS was 209 days (95% CI, 128–236 days). Patients with chronic GVHD had better survival—median OS 426 days (95% CI, 194–NE days) vs 143 days (95% CI, 114–226 days) (P=0.010). Thus, NST may induce meaningful clinical responses in patients with advanced NPC
Shrike predation on the lizard Mesalina adramitana in Qatar; a review of reported reptile and amphibian prey
We report, for the first time, evidence of predation by a shrike (Lanius sp.) on the lizard Mesalina adramitana. This is the first record of predation by shrikes on lizards in Qatar. Whilst we did not directly observe the event, the presence of shrikes in the area and the method of impalement indicate shrikes as the predator. The lizard was found freshly impaled on a palm tree (Phoenix dactylifera), at 150 cm above ground. Bird species of the genus Lanius are well-known predators of lizards, and in arid environments reptiles are likely common prey for these birds. We provide a review of literature concerning predatory events by shrikes on reptiles and amphibians. We suggest inspection of shrubs for animals impaled by shrikes can improve biodiversity inventories, complementing other commonly used methods
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