Drumlin relief

Drumlin relief is a key parameter for testing predictions of models of drumlin formation. Although this metric is commonly described in textbooks as being of the order of a fewtens ofmetres, our critical review of the literature suggests an average value of about 13 m, but withmuch uncertainty. Hereweinvestigate a large sample of drumlins (25,848) mapped from a high resolution digital terrain model of Britain, which allowed the identification of extremely shallow drumlins. Results indicate that most drumlins have a relief between 0.5 and 40m (with a surprisingly low average value of only 7.1 m) a mode of 3.5–4 m, and with 41% of all drumlins characterized by a relief < 5 m. Drumlin relief is found to never exceed 7% of the width and is positively correlated with this parameter, possibly indicating that drumlins need a large base to stand against the flow of the ice. Drumlin relief is also positively correlated with the length, which shows that drumlins do not grow in length by redistributing sediments from their summits to their downflow (lee) end, as previously hypothesised.publishedVersio

A Picture May Be Worth a Thousand Texts: Obese Adolescents' Perspectives on a Modified Photovoice Activity To Aid Weight Loss

Abstract Background: In an effort to enhance the vividness and personal relevance of a text messaging intervention to promote weight loss among obese adolescents, a modified Photovoice process was evaluated with adolescents in a weight management program. Methods: Photovoice is a method using photography to generate relevant images and stories from users. Participants were recruited from the Michigan Pediatric Outpatient Weight Evaluation and Reduction (MPOWER) program, a multidisciplinary weight management program for obese adolescents and their parents. Twenty-three adolescents with a mean BMI of 40 were asked to take pictures on three to five randomly assigned weight-related topics, such as ?something that reminds you to exercise,? and to text them to a research assistant. Adolescents then engaged in semistructured interviews about the experience. Detailed notes of the interviews were analyzed to identify themes. Results: Participants generally provided high ratings of the process, indicating that (1) deciding what pictures to take caused them to reflect on their weight loss experience, and (2) a mobile intervention incorporating personally relevant images (e.g., basketball as their favorite sport rather than sports in general) would increase treatment adherence. The submitted photographs frequently featured family members and friends, and participants indicated that family and friends played a major role in motivating and supporting them. Conclusions: This study suggests that a Photovoice component has the potential to enhance weight management programs for teens as part of a text messaging intervention and as an independent entity. Further work should evaluate the effect of this promising intervention on weight loss.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98440/1/chi%2E2011%2E0095.pd

When Does Eddy Viscosity Damp Subfilter Scales Sufficiently?

Large eddy simulation (LES) seeks to predict the dynamics of spatially filtered turbulent flows. The very essence is that the LES-solution contains only scales of size ≥Δ, where Δ denotes some user-chosen length scale. This property enables us to perform a LES when it is not feasible to compute the full, turbulent solution of the Navier-Stokes equations. Therefore, in case the large eddy simulation is based on an eddy viscosity model we determine the eddy viscosity such that any scales of size <Δ are dynamically insignificant. In this paper, we address the following two questions: how much eddy diffusion is needed to (a) balance the production of scales of size smaller than Δ; and (b) damp any disturbances having a scale of size smaller than Δ initially. From this we deduce that the eddy viscosity νe has to depend on the invariants q = ½tr(S^2) and r =−⅓tr(S^3) of the (filtered) strain rate tensor S. The simplest model is then given by νe = 3/2(Δ/π)^2|r|/q. This model is successfully tested for a turbulent channel flow (Reτ = 590).

Observation of Parity Violation in the Omega-minus -> Lambda + K-minus Decay

The alpha decay parameter in the process Omega-minus -> Lambda + K-minus has been measured from a sample of 4.50 million unpolarized Omega-minus decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [1.78 +/- 0.19(stat) +/- 0.16(syst)]{\times}10^{-2}. This is the first unambiguous evidence for a nonzero alpha decay parameter, and hence parity violation, in the Omega-minus -> Lambda + K-minus decay.Comment: 10 pages, 7 figure

HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in $\Xi$ and $\Lambda$ hyperon decays with a sensitivity of $10^{-4}$. Intense charged secondary beams were produced by 800 GeV/c protons and momentum-selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in twelve months of data-taking.Comment: 107 pages, 45 Postscript figures, 14 tables, Elsevier LaTeX, submitted to Nucl. Instrum. Meth.

Inflammation Dynamically Regulates Steroid Hormone Metabolism and Action within Macrophages in Rheumatoid Arthritis

Rationale: In inflammatory diseases such as rheumatoid arthritis (RA), steroid metabolism is a central component mediating the actions of immuno-modulatory glucocorticoids and sex steroids. However, the regulation and function of cellular steroid metabolism within key leukocyte populations such as macrophages remain poorly defined. In this study, the inflammatory regulation of global steroid metabolism was assessed in RA macrophages. Methods: Bulk RNA-seq data from RA synovial macrophages was used to assess transcripts encoding key enzymes in steroid metabolism and signalling. Changes in metabolism were assessed in synovial fluids, correlated to measures of disease activity and functionally validated in primary macrophage cultures. Results: RNA-seq revealed a unique pattern of differentially expressed genes, including changes in genes encoding the enzymes 11β-HSD1, SRD5A1, AKR1C2 and AKR1C3. These correlated with disease activity, favouring increased glucocorticoid and androgen levels. Synovial fluid 11β-HSD1 activity correlated with local inflammatory mediators (TNFα, IL-6, IL-17,), whilst 11β-HSD1, SRD5A1 and AKR1C3 activity correlated with systemic measures of disease and patient pain (ESR, DAS28 ESR, global disease activity). Changes in enzyme activity were evident in inflammatory activated macrophages in vitro and revealed a novel androgen activating role for 11β-HSD1. Together, increased glucocorticoids and androgens were able to suppress inflammation in macrophages and fibroblast-like-synoviocytes. Conclusions: This study underscores the significant increase in androgen and glucocorticoid activation within inflammatory polarized macrophages of the synovium, contributing to local suppression of inflammation. The diminished profile of inactive steroid precursors in postmenopausal women may contribute to disturbances in this process, leading to increased disease incidence and severity.<br/

OMG Do Not Say LOL: Obese Adolescents' Perspectives on the Content of Text Messages to Enhance Weight Loss Efforts

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93769/1/oby.2011.266.pd

Relationships of Sleep Duration, Midpoint, and Variability with Physical Activity in the HCHS/SOL Sueño Ancillary Study

Objective/Background: Short and long sleep duration, later sleep midpoint, and greater intra-individual sleep variability are associated with lower physical activity, but previous research lacks objective and concurrent assessment of sleep and physical activity. This cross-sectional study examined whether sleep duration, midpoint, and variability in duration and midpoint were related to wrist actigraphy-measured physical activity. Participants: Participants were 2156 Hispanics/Latinos in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Sueño Ancillary Study. Methods: Participants wore Actiwatch devices to measure sleep and physical activity via the wrist for ≥5 days. Physical activity was defined as minutes/day in the upper quartile of the sampling distribution’s non-sleep activity, capturing light to vigorous physical activity. Results: An inverse linear relationship between sleep duration and physical activity was found such that each additional sleep hour related to 29 fewer minutes of physical activity (B = −28.7, SE = 3.8), p <.01). Variability in sleep midpoint was also associated with physical activity; with each 1-hr increase in variability there were 24 more minutes of physical activity (B = 24.2, SE = 5.6, p <.01). In contrast, sleep midpoint and variability in duration were not associated with physical activity. Sensitivity analyses identified an association of short sleep duration and greater variability in sleep duration with greater accelerometry-derived moderate-to-vigorous physical activity measured at the HCHS/SOL baseline (M = 2.1 years before the sleep assessment). Conclusions: Findings help clarify inconsistent prior research associating short sleep duration and sleep variability with greater health risks but also contribute novel information with simultaneous objective assessments