Slippage and Migration in Taylor-Couette Flow of a Model for Dilute Wormlike Micellar Solutions

Submitted to J. Non-Newt Fluid Mechanics, June 2005In this paper we explore a model, most appropriate for dilute or semi-dilute worm-like micellar solutions, in an axisymmetric circular Taylor-Couette geometry. This study is a natural continuation of earlier work on rectilinear shear flows. The model, based on a bead-spring microstructure with nonaffine motion, reproduces the pronounced plateau in the stress strain-rate flow curve as observed in laboratory measurements of steady shearing flows. We also carry out a linear stability analysis of the computed steady state solutions. The results show shear-banding in the form of sharp changes in velocity gradients, spatial variations in number density, and in alignment or stretching of the micelles. The velocity profiles obtained in numerical solutions show strong qualitative agreement with those of laboratory experiments.NSF Collaborative Research Projec

Aspects of surrealism in the work of Jean Cocteau

The work of Jean Cocteau reveals connections, similarities and differences between him and the writers of the surrealist movement. In order to appreciate the links it is also necessary to examine the principles of Surrealism to determine the extent to which they have similar origins to some of Cocteau's own ideas.This line of inquiry leads to an examination of the part played by the work of Freud and Jung in inspiring both Surrealism and Cocteau. To a certain degree one is lead to question the association between Freud and Surrealism which has often been taken for granted and to look for the origins of surrealistic thought in more specifically French sources to which Freud also had access. Whilst it is difficult to bring about a rapprochement between Cocteau and Freud, there is a much smaller problem in comparing the work of Jung and that of Cocteau. There are striking similarities which indicate not only a divergence of thought between Cocteau and the surrealists but which also tempt one to extrapolate a direct link between Cocteau and Jung for which there is virtually no direct evidence. What is achieved in comparing the two is a greater understanding of the creative method of Cocteau, of the forces which drove him, and of his basic position as a child of the 20th century, yet as a poet of all ages. One begins also to have a clearer vision of the reasons which underlie his all important interest in mythology as a source of pure emotion and distilled poetic essence. For personal rather than artistic reasons a close rapport between Cocteau and the surrealist group is unthinkable as well as generally known, so that there is an enhanced interest not only in a direct comparison but also in comparing Cocteau with artists and poets who worked close to official movement but were not, at least for very long, part of it. Garcia Lorca is a Spanish writer in this position whose ideas and background so closely,resemble Cocteau's that it is almost surprising to find that he was at least tolerated if not completely accepted by the Surrealists; his friends Dalí and and Bunuel even joined the group formally. On the other hand Cocteau's proclaimed admiration for Garcia Lorca indicated at least some feeling in not being able to participate directly in the Surrealist experience. Comparing Cocteau with Lorca necessitates an examination of the creeds and ideals of them both, highlighting aspects of poetic power and creativity in the process.It is hoped to place in the context of 20th century thought the work of both Cocteau and the Surrealists. A continuity between the second half of the nineteenth century and the twentieth century should also be established and the manner in which the First World War acts as a watershed made clear. From the study Cocteau emerges as a more consistent and deeper thinker than he is often considered. The parallels found in the work which he presented in a variety of different artistic fields coupled with the overpowering sense of mission which begins to appear, dispel for ever the myths of the careless and carefree casual adolescent dilettante and reveal instead a conscious artist, a thinking poet, a careful craftsman and a profoundly proud human figure wrought with deep seated anxieties often masqued with flippancy. Undeniably however, consciously or unconsciously, whether or not the Surrealist liked the idea, there was an affinity between them and Cocteau which was sometimes a very close link and at others flared up into an open hostility which at least indicated that they were working in the same areas.Since it was the fashion at the time to accept the view of Freud as a scientist and a medical practitioner in the field of psychiatry, a view which he himself insisted upon, it has been felt justifiable to accept it, although nowadays he is partially discredited. The concept of the subconscious is also not considered favourably although it seemed real to Freud, Jung, the Surrealists and to Cocteau. Consequently it is desirable to work within the parameters of their imagination rather than to take the stance of modern behaviourist psychiatrists whose ideas are irrelevant to the literary uses made of the work of Freud and Jung

Upscaling CH4 Fluxes Using High-Resolution Imagery in Arctic Tundra Ecosystems

© 2017 by the author. Arctic tundra ecosystems are a major source of methane (CH 4 ), the variability of which is affected by local environmental and climatic factors, such as water table depth, microtopography, and the spatial heterogeneity of the vegetation communities present. There is a disconnect between the measurement scales for CH 4 fluxes, which can be measured with chambers at one-meter resolution and eddy covariance towers at 100-1000 m, whereas model estimates are typically made at the ~100 km scale. Therefore, it is critical to upscale site level measurements to the larger scale for model comparison. As vegetation has a critical role in explaining the variability of CH 4 fluxes across the tundra landscape, we tested whether remotely-sensed maps of vegetation could be used to upscale fluxes to larger scales. The objectives of this study are to compare four different methods for mapping and two methods for upscaling plot-level CH 4 emissions to the measurements from EC towers. We show that linear discriminant analysis (LDA) provides the most accurate representation of the tundra vegetation within the EC tower footprints (classification accuracies of between 65% and 88%). The upscaled CH 4 emissions using the areal fraction of the vegetation communities showed a positive correlation (between 0.57 and 0.81) with EC tower measurements, irrespective of the mapping method. The area-weighted footprint model outperformed the simple area-weighted method, achieving a correlation of 0.88 when using the vegetation map produced with the LDA classifier. These results suggest that the high spatial heterogeneity of the tundra vegetation has a strong impact on the flux, and variation indicates the potential impact of environmental or climatic parameters on the fluxes. Nonetheless, assimilating remotely-sensed vegetation maps of tundra in a footprint model was successful in upscaling fluxes across scales

Working atmosphere in the secondary mathematics classroom: When things do not work according to the lesson plan

In this paper we focus on a collaborative research and development project in which a team consisting of secondary mathematics teachers (newly qualified and experienced), researchers in mathematics education (faculty and doctoral students) and mathematics teacher educators work together on how to achieve balance between creating opportunities for high quality mathematical thinking and attending to classroom management and behaviour issues. To this aim we deploy Haydn’s 10-point scale on the working atmosphere in the classroom. This construct was not devised specifically for the mathematics classroom and our study explores its potentialities for it: we ask whether a scale (Haydn-M) with mathematics specificity can provide meaningful insight into the working atmosphere in the secondary mathematics classroom. In this paper we provide examples suggested by newly qualified teachers in our team of such a mathematically specific use of the scale

Probing shear-banding transitions of the VCM model for entangled wormlike micellar solutions using large amplitude oscillatory shear (LAOS) deformations

We explore the use of large amplitude oscillatory shear (LAOS) deformation to probe the dynamics of shear-banding in soft entangled materials, primarily wormlike micellar solutions which are prone to breakage and disentanglement under strong deformations. The state of stress in these complex fluids is described by a class of viscoelastic constitutive models which capture the key linear and nonlinear rheological features of wormlike micellar solutions, including the breakage and reforming of an entangled network. At a frequency-dependent critical strain, the imposed deformation field localizes to form a shear band, with a phase response that depends on the frequency and amplitude of the forcing. The different material responses are compactly represented in the form of Lissajous (phase plane) orbits and a corresponding strain-rate and frequency-dependent Pipkin diagram. Comparisons between the full network model predictions and those of a simpler, limiting case are presented.National Science Foundation (U.S.) (NSF DMS-0807395)National Science Foundation (U.S.) (NSF DMS-0807330

Aberrant mucin assembly in mice causes endoplasmic reticulum stress and spontaneous inflammation resembling ulcerative colitis

BACKGROUND: MUC2 mucin produced by intestinal goblet cells is the major component of the intestinal mucus barrier. The inflammatory bowel disease ulcerative colitis is characterized by depleted goblet cells and a reduced mucus layer, but the aetiology remains obscure. In this study we used random mutagenesis to produce two murine models of inflammatory bowel disease, characterised the basis and nature of the inflammation in these mice, and compared the pathology with human ulcerative colitis. METHODS AND FINDINGS: By murine N-ethyl-N-nitrosourea mutagenesis we identified two distinct noncomplementing missense mutations in Muc2 causing an ulcerative colitis-like phenotype. 100% of mice of both strains developed mild spontaneous distal intestinal inflammation by 6 wk (histological colitis scores versus wild-type mice, p , 0.01) and chronic diarrhoea. Monitoring over 300 mice of each strain demonstrated that 25% and 40% of each strain, respectively, developed severe clinical signs of colitis by age 1 y. Mutant mice showed aberrant Muc2 biosynthesis, less stored mucin in goblet cells, a diminished mucus barrier, and increased susceptibility to colitis induced by a luminal toxin. Enhanced local production of IL-1b, TNF-a, and IFN-c was seen in the distal colon, and intestinal permeability increased 2-fold. The number of leukocytes within mesenteric lymph nodes increased 5-fold and leukocytes cultured in vitro produced more Th1 and Th2 cytokines (IFN-c, TNF-a, and IL-13). This pathology was accompanied by accumulation of the Muc2 precursor and ultrastructural and biochemical evidence of endoplasmic reticulum (ER) stress in goblet cells, activation of the unfolded protein response, and altered intestinal expression of genes involved in ER stress, inflammation, apoptosis, and wound repair. Expression of mutated Muc2 oligomerisation domains in vitro demonstrated that aberrant Muc2 oligomerisation underlies the ER stress. In human ulcerative colitis we demonstrate similar accumulation of nonglycosylated MUC2 precursor in goblet cells together with ultrastructural and biochemical evidence of ER stress even in noninflamed intestinal tissue. Although our study demonstrates that mucin misfolding and ER stress initiate colitis in mice, it does not ascertain the genetic or environmental drivers of ER stress in human colitis. CONCLUSIONS: Characterisation of the mouse models we created and comparison with human disease suggest that ER stress-related mucin depletion could be a fundamental component of the pathogenesis of human colitis and that clinical studies combining genetics, ER stress-related pathology and relevant environmental epidemiology are warranted. The Editors’ Summary of this article follows the references

Social democracy, embeddedness and decommodification: On the conceptual innovations and intellectual affiliations of Karl Polanyi

Of the several debates that revolve around the work of the economic historian and political economist Karl Polanyi, one that continues to exercise minds concerns his analysis of, and political attitudes toward, post-war capitalism and the welfare state. Simplified a little, it is a debate with two sides. To borrow Iván Szelényi's terms, one side constructs a ‘hard’ Karl Polanyi, the other a ‘soft’ one. The former advocated a socialist mixed economy dominated by redistributive mechanisms. He was a radical socialist for whom the market should never be the dominant mechanism of economic coordination. His ‘soft’ alter ego insisted that the market system remain essentially intact but be complemented by redistributive mechanisms. The ‘double movement’ – the central thesis of his ‘Great Transformation’ – acts, in this reading, as a self-correcting mechanism that moderates the excesses of market fundamentalism; its author was positioned within the social-democratic mainstream for which the only realistic desirable goal is a regulated form of capitalism. In terms of textual evidence there is much to be said for both interpretations. In this article I suggest a different approach, one that focuses upon the meaning of Polanyi's concepts in relation to their socio-political and intellectual environment

The spectrum and clinical impact of epigenetic modifier mutations in myeloma

Epigenetic dysregulation is known to be an important contributor to myeloma pathogenesis but, unlike in other B cell malignancies, the full spectrum of somatic mutations in epigenetic modifiers has not been previously reported. We sought to address this using results from whole-exome sequencing in the context of a large prospective clinical trial of newly diagnosed patients and targeted sequencing in a cohort of previously treated patients for comparison.Whole-exome sequencing analysis of 463 presenting myeloma cases entered in the UK NCRI Myeloma XI study and targeted sequencing analysis of 156 previously treated cases from the University of Arkansas for Medical Sciences. We correlated the presence of mutations with clinical outcome from diagnosis and compared the mutations found at diagnosis with later stages of disease.In diagnostic myeloma patient samples we identify significant mutations in genes encoding the histone 1 linker protein, previously identified in other B-cell malignancies. Our data suggest an adverse prognostic impact from the presence of lesions in genes encoding DNA methylation modifiers and the histone demethylase KDM6A/UTX. The frequency of mutations in epigenetic modifiers appears to increase following treatment most notably in genes encoding histone methyltransferases and DNA methylation modifiers.Numerous mutations identified raise the possibility of targeted treatment strategies for patients either at diagnosis or relapse supporting the use of sequencing-based diagnostics in myeloma to help guide therapy as more epigenetic targeted agents become available

Risks of breast or ovarian cancer in BRCA1 or BRCA2 predictive test negatives: findings from the EMBRACE study.

Purpose BRCA1/BRCA2 predictive test negatives are proven noncarriers of a BRCA1/BRCA2 mutation that is carried by their relatives. The risk of developing breast cancer (BC) or epithelial ovarian cancer (EOC) in these women is uncertain. The study aimed to estimate risks of invasive BC and EOC in a large cohort of BRCA1/BRCA2 predictive test negatives. Methods We used cohort analysis to estimate incidences, cumulative risks, and standardized incidence ratios (SIRs). Results A total of 1,895 unaffected women were eligible for inclusion in the BC risk analysis and 1,736 in the EOC risk analysis. There were 23 incident invasive BCs and 2 EOCs. The cumulative risk of invasive BC was 9.4% (95% confidence interval (CI) 5.9-15%) by age 85 years and the corresponding risk of EOC was 0.6% (95% CI 0.2-2.6%). The SIR for invasive BC was 0.93 (95% CI 0.62-1.40) in the overall cohort, 0.85 (95% CI 0.48-1.50) in noncarriers from BRCA1 families, and 1.03 (95% CI 0.57-1.87) in noncarriers from BRCA2 families. The SIR for EOC was 0.79 (95% CI 0.20-3.17) in the overall cohort. Conclusion Our results did not provide evidence for elevated risks of invasive BC or EOC in BRCA1/BRCA2 predictive test negatives. Genetics in Medicine advance online publication, 22 March 2018; doi:10.1038/gim.2018.44