Numerical Modeling of Nonhomogeneous Behavior of Structured Soils during Triaxial Tests

The nonhomogeneous behavior of structured soils during triaxial tests has been studied using a finite element model based on the Structured Cam Clay constitutive model with Biot-type consolidation. The effect of inhomogeneities caused by the end restraint is studied by simulating drained triaxial tests for samples with a height to diameter ratio of 2. It was discovered that with the increase in degree of soil structure with respect to the same soil at the reconstituted state, the inhomogeineities caused by the end restraint will increase. By loading the sample at different strain rates and assuming different hydraulic boundary conditions, inhomogeneities caused by partial drainage were investigated. It was found that if drainage is allowed from all faces of the specimen, fully drained tests can be carried out at strain rates about ten times higher than those required when the drainage is allowed only in the vertical direction at the top and bottom of the specimen, confirming the findings of previous studies. Both end restraint and partial drainage can cause bulging of the triaxial specimen around mid-height. Inhomogeneities due to partial drainage influence the stress–strain behavior during destructuring, a characteristic feature of a structured soil. With an increase in the strain rate, the change in voids ratio during destructuration reduces, but, in contrast, the mean effective stress at which destructuration commences was found to increase. It is shown that the stress–strain behavior of the soil calculated for a triaxial specimen with inhomogeneities, based on global measurements of the triaxial response, does not represent the true constitutive behavior of the soil inside the test specimen. For most soils analyzed, the deviatoric stress based on the global measurements is about 25% less than that for the soil inside the test specimen, when the applied axial strain is about 30%. Therefore it can be concluded that the conventional global measurements of the sample response may not accurately reflect the true stress–strain behavior of a structured soil. This finding has major implications for the interpretation of laboratory triaxial tests on structured soils

Dispersive line shape in the vicinity of the {\nu} = 1 quantum Hall state: Coexistence of Knight shifted and unshifted resistively detected NMR responses

The frequency splitting between the dip and the peak of the resistively detected nuclear magnetic resonance (RDNMR) dispersive line shape (DLS) has been measured in the quantum Hall effect regime as a function of filling factor, carrier density and nuclear isotope. The splitting increases as the filling factor tends to {\nu} = 1 and is proportional to the hyperfine coupling, similar to the usual Knight shift versus {\nu}-dependence. The peak frequency shifts linearly with magnetic field throughout the studied filling factor range and matches the unshifted substrate signal, detected by classical NMR. Thus, the evolution of the splitting is entirely due to the changing Knight shift of the dip feature. The nuclear spin relaxation time, T1, is extremely long (hours) at precisely the peak frequency. These results are consistent with the local formation of a {\nu} = 2 phase due to the existence of spin singlet D$^-$ complexes.Comment: to be published in Rapid Communication PR

Geometric morphometrics defines shape differences in the cortical area map of C57BL/6J and DBA/2J inbred mice

BACKGROUND: We previously described planar areal differences in adult mouse visual, somatosensory, and neocortex that collectively discriminated C57BL/6J and DBA/2J inbred strain identity. Here we use a novel application of established methods of two-dimensional geometric morphometrics to examine shape differences in the cortical area maps of these inbred strains. RESULTS: We used Procrustes superimposition to align a reliable set of landmarks in the plane of the cortical sheet from tangential sections stained for the cytochrome oxidase enzyme. Procrustes superimposition translates landmark configurations to a common origin, scales them to a common size, and rotates them to minimize an estimate of error. Remaining variation represents shape differences. We compared the variation in shape between C57BL/6J and DBA/2J relative to that within each strain using a permutation test of Goodall's F statistic. Significant differences in shape in the posterior medial barrel subfield (PMBSF), as well as differences in shape across primary sensory areas, characterize the cortical area maps of these common inbred, isogenic strains. CONCLUSION: C57BL/6J and DBA/2J have markedly different cortical area maps, in both size and shape. These differences suggest polymorphism in genetic factors underlying cortical specification, even between common isogenic strains. Comparing cortical phenotypes between normally varying inbred mice or between genetically modified mice can identify genetic contributions to cortical specification. Geometric morphometric analysis of shape represents an additional quantitative tool for the study of cortical development, regardless of whether it is studied from phenotype to gene or gene to phenotype

Care during the third stage of labour: A postal survey of UK midwives and obstetricians

<p>Abstract</p> <p>Background</p> <p>There are two approaches to care during the third stage of labour: Active management includes three components: administration of a prophylactic uterotonic drug, cord clamping and controlled cord traction. For physiological care, intervention occurs only if there is clinical need. Evidence to guide care during the third stage is limited and there is variation in recommendations which may contribute to differences in practice. This paper describes current UK practice during the third stage of labour.</p> <p>Methods</p> <p>A postal survey of 2230 fellows and members of the Royal College of Obstetricians and Gynaecologists (RCOG) and 2400 members of the Royal College of Midwives was undertaken. Respondents were asked about care during the third stage of labour, for vaginal and caesarean births and their views on the need for more evidence to guide care in the third stage. The data were analysed in Excel and presented as descriptive statistics.</p> <p>Results</p> <p>1189 (53%) fellows and members of the RCOG and 1702 (71%) midwives responded, of whom 926 (78%) and 1297 (76%) respectively had conducted or supervised births in the last year. 93% (863/926) of obstetricians and 73% (942/1297) of midwives report 'always or usually' using active management. 66% (611/926) of obstetricians and 33% (430/1297) of midwives give the uterotonic drug with delivery of the anterior shoulder; this was intramuscular Syntometrine^®for 79% (728/926) and 86% (1118/1293) respectively. For term births, 74% (682/926) of obstetricians and 41% (526/1297) of midwives clamp the cord within 20 seconds, as do 57% (523/926) and 55% (707/1297) for preterm births. Controlled cord traction was used by 94% of both obstetricians and midwives. For caesarean births, intravenous oxytocin was the uterotonic used by 90% (837/926) of obstetricians; 79% (726/926) clamp the cord within 20 seconds for term births as do 63% (576/926) for preterm births.</p> <p>Physiological management was used 'always or usually' by 2% (21/926) of obstetricians and 9% (121/1297) of midwives. 81% (747/926) of obstetricians and 89% (1151/1297) of midwives thought more evidence from randomised trials was needed; the most popular question was when is best to clamp the cord.</p> <p>Conclusions</p> <p>Active management of the third stage of labour is widely used by both obstetricians and midwives in the UK. Syntometrine^®is usually used for vaginal births and oxytocin for caesarean births; when this is given and when the cord is clamped varies.</p

Genetics of the Hippocampal Transcriptome in Mouse: A Systematic Survey and Online Neurogenomics Resource

Differences in gene expression in the CNS influence behavior and disease susceptibility. To systematically explore the role of normal variation in expression on hippocampal structure and function, we generated an online microarray database for a diverse panel of strains of mice, including most common inbred strains and numerous recombinant inbred lines (www.genenetwork.org). Using this resource, coexpression networks for families of genes can be generated rapidly to test causal models related to function. The data set is optimized for quantitative trait locus (QTL) mapping and was used to identify over 5500 QTLs that modulate mRNA levels. We describe a wide variety of analyses and novel synthetic approaches that take advantage of this resource, and demonstrate how both the data and associated tools can be applied to the study of gene regulation in the hippocampus and relations to structure and function

Moisture sensitivity examination of asphalt mixtures using thermodynamic, direct adhesion peel and compacted mixture mechanical tests

Moisture damage in asphalt mixtures is a complicated mode of pavement distress that results in the loss of stiffness and structural strength of the asphalt pavement layers. This paper evaluated the moisture sensitivity of different aggregate–bitumen combinations through three different approaches: surface energy, peel adhesion and the Saturation Ageing Tensile Stiffness (SATS) tests. In addition, the results obtained from these three tests were compared so as to characterise the relationship between the thermodynamic and the mechanical tests. The surface energy tests showed that the work of adhesion in dry conditions was bitumen type dependent, which is in agreement with the peel test. After moisture damage, all of these three tests found that the moisture sensitivity of aggregate–bitumen combinations were mainly aggregate type dependent. Based on the peel test, the moisture absorption and mineralogical compositions of aggregate were considered as two important factors to moisture sensitivity. This phenomenon suggests that in a susceptible asphalt mixture, the effect of aggregate may be more influential than the effect of bitumen. The SATS test and the peel test showed similar moisture sensitivity results demonstrating the good correlation between these two mechanical tests. However, the surface energy tests and the mechanical tests cannot correlate in terms of moisture sensitivity evaluation

Films and critical pedagogy in management education: A tourism studies context

This article examines and critically assesses the role of films in the practice of critical pedagogy in undergraduate management education, using tourism studies as a context. Utilising online focus groups, it aims to gain an in-depth knowledge and understanding of the role of films as an effective pedagogical medium in enhancing experiential approaches to learning. It argues that films play an important role in facilitating critical analyses of the studied phenomenon, illustrating and problematising abstract concepts and ideas, as well as in facilitating students’ ability to discern multiple and alternative discourses about management. The findings highlight the role of films in context-specific critical engagement with the studied content and in stimulating emotionality in learning development, thereby enhancing deep approaches to learning. Emotional responses, even negative ones, prove to be critical in engaging with intellectual and critical reflection after watching films. The findings yield new and empirical insights into the pedagogic use of films in management education, thereby contributing to some of the goals of critical management studies

A Rapid New Assay to Detect RNA Editing Reveals Antipsychotic-Induced Changes in Serotonin-2C Transcripts

ABSTRACT We report the development of a new assay as an alternative to direct DNA sequencing to measure RNA-edited variation in tissue. The new assay has been validated and is accurate, cheaper, more rapid, and less labor-intensive than DNA sequencing. We also outline the statistical modeling required for analyses of the hierarchical, clustered RNA-editing data generated in these studies. Using the new technique, we analyzed the effects of long-term antipsychotic medication on serotonin-2C receptor (5-HT 2C R) RNA editing in rat brain. Our hypothesis that a drug with high affinity for 5-HT 2C R, such as clozapine, would alter its RNA-editing profile was not confirmed. Whereas haloperidol, a typical antipsychotic drug that is primarily a dopamine receptor antagonist, reduced 5-HT 2C VNV isoform frequency and the level of RNA editing at the D site, risperidone and not the prototype atypical antipsychotic drug clozapine increased the frequency of 5-HT 2C VNV and D-site editing. Our data emphasize that caution is required in the interpretation of RNA-editing data in studies of psychiatric disorders, because these studies usually include subjects who received long-term exposure to medication. This newly established method will facilitate high-throughput investigations of RNA editing in disease pathology and in the pharmacological activity of drugs. The revelation that the human genome comprises between 30,000 and 40,000 protein-coding genes was unexpected, because such few genes are unlikely to explain the functional diversity between humans and less complex organisms. These interspecies differences could arise from post-transcriptional processes such as RNA editing and alternative splicing, which allow a single gene to generate several protein variants. The current study focuses on RNA editing. The recent detection of 1637 potential new substrates for RNA editing Because of their relatively recent discovery, substrates of RNA editing have not been extensively characterized. Adenine-to-inosine RNA editing in mammalian brain has been identified in ionotropic receptors (such as the GluR2 subunit of the ␣-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor) and in the serotonin (5-HT)-2C receptor (R), which is coupled to GTP-binding protein. Discrepancies between genomic DNA and cDNA sequences led to the discovery of nucleotide changes caused by the activity of ADAR enzymes. In the fully edited 5-HT 2C R, three amino acid codons in the pre-mRNA are changed so that the sequence coding for IRNPI becomes VRGP

Teaching the Process of Science: Faculty Perceptions and an Effective Methodology

Most scientific endeavors require science process skills such as data interpretation, problem solving, experimental design, scientific writing, oral communication, collaborative work, and critical analysis of primary literature. These are the fundamental skills upon which the conceptual framework of scientific expertise is built. Unfortunately, most college science departments lack a formalized curriculum for teaching undergraduates science process skills. However, evidence strongly suggests that explicitly teaching undergraduates skills early in their education may enhance their understanding of science content. Our research reveals that faculty overwhelming support teaching undergraduates science process skills but typically do not spend enough time teaching skills due to the perceived need to cover content. To encourage faculty to address this issue, we provide our pedagogical philosophies, methods, and materials for teaching science process skills to freshman pursuing life science majors. We build upon previous work, showing student learning gains in both reading primary literature and scientific writing, and share student perspectives about a course where teaching the process of science, not content, was the focus. We recommend a wider implementation of courses that teach undergraduates science process skills early in their studies with the goals of improving student success and retention in the sciences and enhancing general science literacy