380 research outputs found

    Assessing vertical axis rotations in large-magnitude extensional settings: A transect across the Death Valley extended terrane, California

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    Models for Neogene crustal deformation in the central Death Valley extended terrane, southeastern California, differ markedly in their estimates of upper crustal extension versus shear translations. Documentation of vertical axis rotations of range-scale crustal blocks (or parts thereof) is critical when attempting to reconstruct this highly extended region. To better define the magnitude, aerial extent, and timing of vertical axis rotation that could mark shear translation of the crust in this area, paleomagnetic data were obtained from Tertiary igneous and remagnetized Paleozoic carbonate rocks along a roughly east-west traverse parallel to about 36°N latitude. Sites were established in ∼7 to 5 Ma volcanic sequences (Greenwater Canyon and Brown's Peak) and the ∼10 Ma Chocolate Sundae Mountain granite in the Greenwater Range, ∼8.5 to 7.5 Ma and 5 to 4 Ma basalts on the east flank of the Black Mountains, the 10.6 Ma Little Chief stock and upper Miocene(?) basalts in the eastern Panamint Mountains, and Paleozoic Pogonip Group carbonate strata in the north central Panamint Mountains. At the site level, most materials yield readily interpretable paleomagnetic data. Group mean directions, after appropriate structural corrections, suggest no major vertical axis rotation of the Greenwater Range (e.g., D = 359°, I = 46°, α_(95) = 8.0°, N = 12 (7 normal (N), 5 reversed (R) polarity sites)), little post-5 Ma rotation of the eastern Black Mountains (e.g., D = 006°, I = 61°, α_(95) = 4.0°, N = 9 N, 6 R sites), and no significant post-10 Ma rotation of the Panamint Range (e.g., D = 181°, I = −51°, α_(95) = 6.5°, N = 9 R sites). In situ data from the Greenwater Canyon volcanic rocks, Chocolate Sundae Mountain granite, Funeral Peak basalt rocks, the Little Chief stock, and Paleozoic carbonate rocks (remagnetized) are consistent with moderate south east-side-down tilting of the separate range blocks during northwest directed extension. The paleomagnetic data reported here suggest that the Panamints shared none of the 7 Ma to recent clockwise rotation of the Black Mountains crystalline core, as proposed in recent models for transtensional development of the central Death Valley extended terrane

    Standardisation of magnetic nanoparticles in liquid suspension

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    Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way

    Structure and internal deformation of thrust sheets in the Sawtooth Range, Montana: insights from anisotropy of magnetic susceptibility

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    Geological strain analysis of sedimentary rocks is commonly carried out using clast-based techniques. In the absence of valid strain markers, it can be difficult to identify the presence of an early tectonic fabric development and resulting layer parallel shortening (LPS). In order to identify early LPS, we carried out anisotropy of magnetic susceptibility (AMS) analyses on Mississippian limestones from the Sawtooth Range of Montana. The Sawtooth Range is an arcuate zone of north-trending, closely spaced, west-dipping, imbricate thrust sheets that place Mississippian Madison Group carbonates above Cretaceous shales and sandstones. This structural regime is part of the cordilleran mountain belt of North America, which resulted from accretion of allochthonous terrains to the western edge of the North American continent. Although the region has a general east–west increase in thrust displacement and related brittle deformation, a similar trend in penetrative deformation or the distribution of tectonic fabrics is not observed in the field or in the AMS results. The range of magnetic fabrics identified in each thrust sheet ranges from bedding controlled depositional fabrics to tectonic fabrics at a high angle to bedding

    Drug Adverse Event Detection in Health Plan Data Using the Gamma Poisson Shrinker and Comparison to the Tree-based Scan Statistic

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    Background: Drug adverse event (AE) signal detection using the Gamma Poisson Shrinker (GPS) is commonly applied in spontaneous reporting. AE signal detection using large observational health plan databases can expand medication safety surveillance. Methods: Using data from nine health plans, we conducted a pilot study to evaluate the implementation and findings of the GPS approach for two antifungal drugs, terbinafine and itraconazole, and two diabetes drugs, pioglitazone and rosiglitazone. We evaluated 1676 diagnosis codes grouped into 183 different clinical concepts and four levels of granularity. Several signaling thresholds were assessed. GPS results were compared to findings from a companion study using the identical analytic dataset but an alternative statistical method—the tree-based scan statistic (TreeScan). Results: We identified 71 statistical signals across two signaling thresholds and two methods, including closely-related signals of overlapping diagnosis definitions. Initial review found that most signals represented known adverse drug reactions or confounding. About 31% of signals met the highest signaling threshold. Conclusions: The GPS method was successfully applied to observational health plan data in a distributed data environment as a drug safety data mining method. There was substantial concordance between the GPS and TreeScan approaches. Key method implementation decisions relate to defining exposures and outcomes and informed choice of signaling thresholds

    The quantification of mRNA in cerebellum tissue: diagnosis, genotype, methylation and expression

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    Background: The COMT gene is located on chromosome 22q11, a region strongly implicated in the aetiology of several psychiatric disorders, in particular schizophrenia. Previous research has suggested that activity and expression of COMT is altered in schizophrenia, and is mediated by one or more polymorphisms within the gene, including the functional Val(158)Met polymorphism. Method: In this study we examined the expression levels of COMT mRNA using quantitative RTPCR in 60 post mortem cerebellum samples derived from individuals with schizophrenia, bipolar disorder, depression, and no history of psychopathology. Furthermore, we have examined the methylation status of two CpG sites in the promoter region of the gene. Results: We found no evidence of altered COMT expression or methylation in any of the psychiatric diagnoses examined. We did, however, find evidence to suggest that genotype is related to COMT gene expression, replicating the findings of two previous studies. Specifically, val(158)met (rs165688; Val allele) rs737865 ( G allele) and rs165599 ( G allele) all showed reduced expression ( P <0.05). Finally, we observe a strong sexual dimorphism in COMT expression, with females exhibiting significantly greater levels of COMT mRNA. Conclusion: The expression of COMT does not appear to be altered in the cerebellum of individuals suffering from schizophrenia, bipolar disorder or depression, but does appear to be influenced by single nucleotide polymorphisms within the gen

    Childbirth and consequent atopic disease: emerging evidence on epigenetic effects based on the hygiene and EPIIC hypotheses

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    Background: In most high and middle income countries across the world, at least 1:4 women give birth by cesarean section. Rates of labour induction and augmentation are rising steeply; and in some countries up to 50 % of laboring women and newborns are given antibiotics. Governments and international agencies are increasingly concerned about the clinical, economic and psychosocial effects of these interventions. Discussion: There is emerging evidence that certain intrapartum and early neonatal interventions might affect the neonatal immune response in the longer term, and perhaps trans-generationally. Two theories lead the debate in this area. Those aligned with the hygiene (or ‘Old Friends’) hypothesis have examined the effect of gut microbiome colonization secondary to mode of birth and intrapartum/neonatal pharmacological interventions on immune response and epigenetic phenomena. Those working with the EPIIC (Epigenetic Impact of Childbirth) hypothesis are concerned with the effects of eustress and dys-stress on the epigenome, secondary to mode of birth and labour interventions. Summary: This paper examines the current and emerging findings relating to childbirth and atopic/autoimmune disease from the perspective of both theories, and proposes an alliance of research effort. This is likely to accelerate the discovery of important findings arising from both approaches, and to maximize the timely understanding of the longer-term consequences of childbirth practices

    Person-Specific Non-shared Environmental Influences in Intra-individual Variability : A Preliminary Case of Daily School Feelings in Monozygotic Twins

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    Most behavioural genetic studies focus on genetic and environmental influences on inter-individual phenotypic differences at the population level. The growing collection of intensive longitudinal data in social and behavioural science offers a unique opportunity to examine genetic and environmental influences on intra-individual phenotypic variability at the individual level. The current study introduces a novel idiographic approach and one novel method to investigate genetic and environmental influences on intra-individual variability by a simple empirical demonstration. Person-specific non-shared environmental influences on intra-individual variability of daily school feelings were estimated using time series data from twenty-one pairs of monozygotic twins (age = 10 years, 16 female pairs) over two consecutive weeks. Results showed substantial inter-individual heterogeneity in person-specific non-shared environmental influences. The current study represents a first step in investigating environmental influences on intra-individual variability with an idiographic approach, and provides implications for future behavioural genetic studies to examine developmental processes from a microscopic angle

    Standardisation of magnetic nanoparticles in liquid suspension

    Get PDF
    Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way
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