50 results
A.1 Repurposing Ambroxol as a disease-modifying treatment for Parkinson’s disease dementia: A phase 2, randomized, double blind placebo-controlled trial
- SH Pasternak, C Silveira, K Coleman, M Borrie, J Wells, E Finger, R Bartha, M Jog, M Jenkins, P MacDonald, G Zou, S Stukas, C Wellington, R Tirona, T Rupar
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 51 / Issue s1 / June 2024
- Published online by Cambridge University Press:
- 24 May 2024, p. S3
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Background: Currently there are no disease modifying treatment for Synucleinopathies including Parkinson’s disease Dementia (PDD). Carrying a mutation in the GBA gene (beta-glucocerebrosidase/ GCAse) is a leading risk factor for synucleinopathies. Raising activity GCAse lowers α-synuclein levels in cells and animal models. Ambroxol is a pharmacological chaperone for GCAse and can raise GCAse levels. Our goal is to test Ambroxol as a disease-modifying treatment in PDD. Methods: We randomized fifty-five individuals with PDD to Ambroxol 1050mg/day, 525mg/day, or placebo for 52 weeks. Primary outcome measures included safety, Alzheimer’s disease Assessment Scale-cognitive (ADAS-Cog) subscale and the Clinician’s Global Impression of Change (CGIC). Secondary outcomes included pharmacokinetics, cognitive and motor outcomes and and plasma and CSF biomarkers. Results: Ambroxol was well tolerated. There were 7 serious adverse events (SAEs) none deemed related to Ambroxol. GCase activity was increased in white blood cells by ~1.5 fold. There were no differences between groups on primary outcome measures. Patients receiving high dose Ambroxol appeared better on the Neuropsychiatric Inventory. GBA carriers appeared to improve on some cognitive tests. pTau 181 was reduced in CSF. Conclusions: Ambroxol was safe and well-tolerated in PDD. Ambroxol may improve biomarkers and cognitive outcomes in GBA1 mutation carrie.rs Ambroxol improved some biomarkerss. ClinicalTrials.gov NCT02914366
Outcomes and characteristics in term infants with necrotising enterocolitis and CHD
- Sean T. Kelleher, John Coleman, Colin J. McMahon, Adam James
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- Cardiology in the Young , First View
- Published online by Cambridge University Press:
- 02 January 2024, pp. 1-7
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Background:
CHD is a significant risk factor for the development of necrotising enterocolitis. Existing literature does not differentiate between term and preterm populations. Long-term outcomes of these patients are not well understood. The aim was to investigate the baseline characteristics and outcomes of term normal birth weight infants with CHD who developed necrotising enterocolitis.
Methods:A retrospective review was performed of infants from a single tertiary centre with CHD who developed necrotising enterocolitis of Bell’s Stage 1–3, over a ten-year period. Inclusion criteria was those born greater than 36 weeks’ gestation and birth weight over 2500g. Exclusion criteria included congenital gastro-intestinal abnormalities. Sub-group analysis was performed using Fisher’s exact test.
Results:Twenty-five patients were identified, with a median gestational age of 38 weeks. Patients with univentricular physiology accounted for 32% (n = 8) and 52% of patients (n = 13) had a duct-dependent lesion. Atrioventricular septal defect was the most common cardiac diagnosis (n = 6, 24%). Patients with trisomy 21 accounted for 20% of cases. Mortality within 30 days of necrotising enterocolitis was 20%. Long-term mortality was 40%, which increased with increasing Bell’s Stage. In total, 36% (n = 9) required surgical management of necrotising enterocolitis, the rate of which was significantly higher in trisomy 21 cases (p < 0.05).
Conclusion:Not previously described in term infants is the high rate of trisomy 21 and atrioventricular septal defect. This may reflect higher baseline incidence in our population. Infants with trisomy 21 were more likely to develop surgical necrotising enterocolitis. Mortality at long-term follow-up was high in patients with Bell’s Stage 2–3.
4 Risk Factor and Biomarker Correlates of FLAIR White Matter Hyperintensities in Former American Football Players
- Monica T Ly, Fatima Tuz-Zahra, Yorghos Tripodis, Charles H Adler, Laura J Balcer, Charles Bernick, Elaine Peskind, Megan L Mariani, Rhoda Au, Sarah J Banks, William B Barr, Jennifer V Wethe, Mark W Bondi, Lisa Delano-Wood, Robert C Cantu, Michael J Coleman, David W Dodick, Michael D McClean, Jesse Mez, Joseph N Palmisano, Brett Martin, Kaitlin Hartlage, Alexander P Lin, Inga K Koerte, Jeffrey L Cummings, Eric M Reiman, Martha E Shenton, Robert A Stern, Sylvain Bouix, Michael L Alosco
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 608-610
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Objective:
White matter hyperintensity (WMH) burden is greater, has a frontal-temporal distribution, and is associated with proxies of exposure to repetitive head impacts (RHI) in former American football players. These findings suggest that in the context of RHI, WMH might have unique etiologies that extend beyond those of vascular risk factors and normal aging processes. The objective of this study was to evaluate the correlates of WMH in former elite American football players. We examined markers of amyloid, tau, neurodegeneration, inflammation, axonal injury, and vascular health and their relationships to WMH. A group of age-matched asymptomatic men without a history of RHI was included to determine the specificity of the relationships observed in the former football players.
Participants and Methods:240 male participants aged 45-74 (60 unexposed asymptomatic men, 60 male former college football players, 120 male former professional football players) underwent semi-structured clinical interviews, magnetic resonance imaging (structural T1, T2 FLAIR, and diffusion tensor imaging), and lumbar puncture to collect cerebrospinal fluid (CSF) biomarkers as part of the DIAGNOSE CTE Research Project. Total WMH lesion volumes (TLV) were estimated using the Lesion Prediction Algorithm from the Lesion Segmentation Toolbox. Structural equation modeling, using Full-Information Maximum Likelihood (FIML) to account for missing values, examined the associations between log-TLV and the following variables: total cortical thickness, whole-brain average fractional anisotropy (FA), CSF amyloid ß42, CSF p-tau181, CSF sTREM2 (a marker of microglial activation), CSF neurofilament light (NfL), and the modified Framingham stroke risk profile (rFSRP). Covariates included age, race, education, APOE z4 carrier status, and evaluation site. Bootstrapped 95% confidence intervals assessed statistical significance. Models were performed separately for football players (college and professional players pooled; n=180) and the unexposed men (n=60). Due to differences in sample size, estimates were compared and were considered different if the percent change in the estimates exceeded 10%.
Results:In the former football players (mean age=57.2, 34% Black, 29% APOE e4 carrier), reduced cortical thickness (B=-0.25, 95% CI [0.45, -0.08]), lower average FA (B=-0.27, 95% CI [-0.41, -.12]), higher p-tau181 (B=0.17, 95% CI [0.02, 0.43]), and higher rFSRP score (B=0.27, 95% CI [0.08, 0.42]) were associated with greater log-TLV. Compared to the unexposed men, substantial differences in estimates were observed for rFSRP (Bcontrol=0.02, Bfootball=0.27, 994% difference), average FA (Bcontrol=-0.03, Bfootball=-0.27, 802% difference), and p-tau181 (Bcontrol=-0.31, Bfootball=0.17, -155% difference). In the former football players, rFSRP showed a stronger positive association and average FA showed a stronger negative association with WMH compared to unexposed men. The effect of WMH on cortical thickness was similar between the two groups (Bcontrol=-0.27, Bfootball=-0.25, 7% difference).
Conclusions:These results suggest that the risk factor and biological correlates of WMH differ between former American football players and asymptomatic individuals unexposed to RHI. In addition to vascular risk factors, white matter integrity on DTI showed a stronger relationship with WMH burden in the former football players. FLAIR WMH serves as a promising measure to further investigate the late multifactorial pathologies of RHI.
453 Rapid SARS-CoV-2 testing with duplexed recombinase polymerase amplification and a bacteriophage internal control
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- Coleman Martin, Andrew T. Bender, Benjamin P. Sullivan, Lorraine Lillis, David S. Boyle, Jonathan Posner
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- Journal:
- Journal of Clinical and Translational Science / Volume 7 / Issue s1 / April 2023
- Published online by Cambridge University Press:
- 24 April 2023, p. 134
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OBJECTIVES/GOALS: Current COVID-19 rapid molecular tests require cartridge-reader detection, expensive circuitry, and complex microfluidics making the most accurate tests unavailable to the masses. Here we present a rapid molecular diagnostic leveraging isothermal amplification and paper-based microfluidics for a low-cost ultra-sensitive COVID-19 assay. METHODS/STUDY POPULATION: We designed a reverse transcription recombinase polymerase amplification (RT-RPA) assay for the detection of SARS-CoV-2 and bacteriophage MS2 RNA. RT-RPA is a sequence specific, ultrasensitive, rapid isothermal DNA amplification technique that is well suited to home based testing due to its rapid assay time, robustness, ease of use, and readout options. RT-RPA reagents are added to a tube and incubated at 39°C in a fluorometer. Realtime fluorometer data gives results in under 15 minutes. This assay also provides visual detection via lateral flow readout with results in 23 minutes. RESULTS/ANTICIPATED RESULTS: We have developed a rapid multiplexed nucleic acid amplification assay with an internal process control for SARS-CoV-2 using single-pot RT-RPA. We screened 21 primer combinations to select primers that demonstrated excellent performance and target specificity against common respiratory viruses. We demonstrate the ability to multiplex SARS-CoV-2 and MS2 detection, utilizing MS2 as an internal process control for lysis, reverse transcription, amplification, and readout. We show duplexed detection using both fluorescence readout and visual readout using lateral flow strips. Duplexed fluorescence detection shows a limit of detection of 25 copies per reaction. Duplexed lateral flow readout shows a limit of detection of 50 copies per reaction DISCUSSION/SIGNIFICANCE: We developed a duplexed RT-RPA assay for SARS-CoV-2 with fluorescence or lateral flow readout. Our assay does not re-quire expensive reader, circuity, or fluid handling. The low material cost, temperature, and robustness make it ideal for a more accurate home-based COVID-19 diagnostic.
College student sleep quality and mental and physical health are associated with food insecurity in a multi-campus study
- Rebecca L Hagedorn, Melissa D Olfert, Lillian MacNell, Bailey Houghtaling, Lanae B Hood, Mateja R Savoie Roskos, Jeannine R Goetz, Valerie Kern-Lyons, Linda L Knol, Georgianna R Mann, Monica K Esquivel, Adam Hege, Jennifer Walsh, Keith Pearson, Maureen Berner, Jessica Soldavini, Elizabeth T Anderson-Steeves, Marsha Spence, Christopher Paul, Julia F Waity, Elizabeth D Wall-Bassett, Melanie D Hingle, E Brooke Kelly, J Porter Lillis, Patty Coleman, Mary Catherine Fontenot
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- Journal:
- Public Health Nutrition / Volume 24 / Issue 13 / September 2021
- Published online by Cambridge University Press:
- 22 March 2021, pp. 4305-4312
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Objective:
To assess the relationship between food insecurity, sleep quality, and days with mental and physical health issues among college students.
Design:An online survey was administered. Food insecurity was assessed using the ten-item Adult Food Security Survey Module. Sleep was measured using the nineteen-item Pittsburgh Sleep Quality Index (PSQI). Mental health and physical health were measured using three items from the Healthy Days Core Module. Multivariate logistic regression was conducted to assess the relationship between food insecurity, sleep quality, and days with poor mental and physical health.
Setting:Twenty-two higher education institutions.
Participants:College students (n 17 686) enrolled at one of twenty-two participating universities.
Results:Compared with food-secure students, those classified as food insecure (43·4 %) had higher PSQI scores indicating poorer sleep quality (P < 0·0001) and reported more days with poor mental (P < 0·0001) and physical (P < 0·0001) health as well as days when mental and physical health prevented them from completing daily activities (P < 0·0001). Food-insecure students had higher adjusted odds of having poor sleep quality (adjusted OR (AOR): 1·13; 95 % CI 1·12, 1·14), days with poor physical health (AOR: 1·01; 95 % CI 1·01, 1·02), days with poor mental health (AOR: 1·03; 95 % CI 1·02, 1·03) and days when poor mental or physical health prevented them from completing daily activities (AOR: 1·03; 95 % CI 1·02, 1·04).
Conclusions:College students report high food insecurity which is associated with poor mental and physical health, and sleep quality. Multi-level policy changes and campus wellness programmes are needed to prevent food insecurity and improve student health-related outcomes.
Planning considerations prior to laryngectomy for a patient infected with severe acute respiratory syndrome coronavirus-2 pre-operatively
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- H Coleman, T Tikka, S Okhovat, S K Kang
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- The Journal of Laryngology & Otology / Volume 134 / Issue 11 / November 2020
- Published online by Cambridge University Press:
- 04 November 2020, pp. 1029-1032
- Print publication:
- November 2020
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Background
Coronavirus disease 2019 was declared a pandemic on 11th March 2020. All non-urgent surgical procedures have been postponed indefinitely. The British Association of Head and Neck Oncology state that only those with treatable head and neck cancer unsuitable for alternative treatment should undergo surgery. This paper details our management of a patient who tested positive for severe acute respiratory syndrome coronavirus-2 days before curative surgery for laryngeal cancer.
Case reportBy following British Association of Head and Neck Oncology guidance, a 49-year-old male scheduled for total laryngectomy and bilateral neck dissection for a T3 transglottic squamous cell cancer was pre-operatively identified as an asymptomatic carrier of severe acute respiratory syndrome coronavirus-2. Following 14-day isolation and laboratory proven viral clearance, he underwent successful major surgery. He was managed throughout the peri- and post-operative phases without complications or adverse effects on staff.
ConclusionWith careful planning, previous coronavirus disease 2019 positive status should not prevent an individual from undergoing successful total laryngectomy and bilateral neck dissection in a safe and timely manner during the pandemic.
Development of a comprehensive, sustained community mental health system in post-earthquake Haiti, 2010–2019
- G. Raviola, A. Rose, J.R. Fils-Aimé, T. Thérosmé, E. Affricot, C. Valentin, S. Daimyo, S. Coleman, W. Dubuisson, J. Wilson, H. Verdeli, G. Belkin, G. Jerome, E. Eustache
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- Global Mental Health / Volume 7 / 2020
- Published online by Cambridge University Press:
- 11 February 2020, e6
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Between 2010 and 2019 the international health care organization Partners In Health (PIH) and its sister organization Zanmi Lasante (ZL) mounted a long-term response to the 2010 Haiti earthquake, focused on mental health. Over that time, implementing a Theory of Change developed in 2012, the organization successfully developed a comprehensive, sustained community mental health system in Haiti's Central Plateau and Artibonite departments, directly serving a catchment area of 1.5 million people through multiple diagnosis-specific care pathways. The resulting ZL mental health system delivered 28 184 patient visits and served 6305 discrete patients at ZL facilities between January 2016 and September 2019. The experience of developing a system of mental health services in Haiti that currently provides ongoing care to thousands of people serves as a case study in major challenges involved in global mental health delivery. The essential components of the effort to develop and sustain this community mental health system are summarized.
Chapter 2 - The Intertidal Zone of the North-East Atlantic Region
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- By Stephen J. Hawkins, Kathryn E. Pack, Louise B. Firth, Nova Mieszkowska, Ally J. Evans, Gustavo M. Martins, Per Åberg, Leoni C. Adams, Francisco Arenas, Diana M. Boaventura, Katrin Bohn, C. Debora G. Borges, João J. Castro, Ross A. Coleman, Tasman P. Crowe, Teresa Cruz, Mark S. Davies, Graham Epstein, João Faria, João G. Ferreira, Natalie J. Frost, John N. Griffin, ME Hanley, Roger J. H. Herbert, Kieran Hyder, Mark P. Johnson, Fernando P. Lima, Patricia Masterson-Algar, Pippa J. Moore, Paula S. Moschella, Gillian M. Notman, Federica G. Pannacciulli, Pedro A. Ribeiro, Antonio M. Santos, Ana C. F. Silva, Martin W. Skov, Heather Sugden, Maria Vale, Kringpaka Wangkulangkul, Edward J. G. Wort, Richard C. Thompson, Richard G. Hartnoll, Michael T. Burrows, Stuart R. Jenkins
- Edited by Stephen J. Hawkins, Marine Biological Association of the United Kingdom, Plymouth, Katrin Bohn, Louise B. Firth, University of Plymouth, Gray A. Williams, The University of Hong Kong
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- Interactions in the Marine Benthos
- Published online:
- 07 September 2019
- Print publication:
- 29 August 2019, pp 7-46
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Summary
The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
Motivating residents to change communication: the role of a brief motivational interviewing didactic
- Lisa Renee Miller-Matero, Erin T. Tobin, Elizabeth Fleagle, Joseph P. Coleman, Anupama Nair
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- Journal:
- Primary Health Care Research & Development / Volume 20 / 2019
- Published online by Cambridge University Press:
- 27 August 2019, e124
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Introduction:
Motivational interviewing (MI) is a patient-centered approach that encourages patients to change behaviors. MI training programs have increased residents’ knowledge and use of MI skills; however, many residency programs may not have the time to dedicate to lengthy MI programs. The purpose of this study was to evaluate the benefits of a brief MI didactic for residents in an academic internal medicine patient-centered medical home.
Methods:Thirty-two residents completed a 1-h MI training between October 2016 and June 2017 and completed measures on their knowledge of, confidence using, and utilization of MI skills prior to the training, immediately after the training, and at a 1-month follow-up.
Results:The residents’ knowledge of and confidence using MI skills increased from pre-test to post-test and also increased from pre-test to the 1-month follow-up.
Conclusion:The utilization of MI skills increased from pre-test to the 1-month follow-up. A 1-h didactic offers benefits to residents.
Engagement through online discussion: perceptions of laying hen welfare in furnished cages
- V. I. Rohlf, T. J. Howell, G. Coleman, J.-L. Rault
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Furnished cage housing for laying hens has been introduced in some countries as a ‘welfare-friendly’ alternative to conventional cage systems. Whether this housing system would be acceptable to the public remains unknown. This pilot study aimed to engage the public through online discussions in order to investigate their knowledge, support and perception of laying hen welfare housed in furnished cages. During these discussions, a science-based information statement about furnished cages was introduced. Through a mixed method approach, surveys to assess beliefs and knowledge were administered to participants before and after the online discussion. We qualitatively analysed the online discussion transcripts to determine recurrent themes, and quantitatively measured levels of knowledge and support for furnished cages using pre- and post-forum surveys. Support for the introduction increased from 55% pre-forum to 65% post-forum. Additionally, the participants’ perceived welfare of laying hens in furnished cages and objective knowledge of furnished cages significantly increased after online discussion. These results suggest that engagement with the public combined with the delivery of science-based information may be important factors when considering whether to introduce new farming practices. Trust in industry through transparency and willingness to engage in discussions with the public might also mitigate public concerns.
Gastropod parasitic nematodes (Phasmarhabditis sp.) are attracted to hyaluronic acid in snail mucus by cGMP signalling
- P. Andrus, O. Ingle, T. Coleman, R. Rae
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- Journal of Helminthology / Volume 94 / 2020
- Published online by Cambridge University Press:
- 15 November 2018, e9
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Phasmarhabditis hermaphrodita is a parasitic nematode of terrestrial gastropods that has been formulated into a biological control agent for farmers and gardeners to kill slugs and snails. In order to locate slugs it is attracted to mucus, faeces and volatile cues; however, there is no information about whether these nematodes are attracted to snail cues. It is also unknown how wild isolates of P. hermaphrodita or different Phasmarhabditis species behave when exposed to gastropod cues. Therefore, we investigated whether P. hermaphrodita (commercial and wild isolated strains), P. neopapillosa and P. californica were attracted to mucus from several common snail species (Cepaea nemoralis, Cepaea hortensis, Arianta arbustorum and Cornu aspersum). We also examined whether snails (C. aspersum) collected from different locations around the UK differed in their attractiveness to wild isolates of P. hermaphrodita. Furthermore, we also investigated what properties of snail mucus the nematodes were attracted to, including hyaluronic acid and metal salts (FeSO4, ZnSO4, CuSO4 and MgSO4). We found that the commercial strain of P. hermaphrodita responded poorly to snail mucus compared to wild isolated strains, and C. aspersum collected from different parts of the UK differed in their attractiveness to the nematodes. We found that Phasmarhabditis nematodes were weakly attracted to all metals tested but were strongly attracted to hyaluronic acid. In a final experiment we also showed that pharmacological manipulation of cyclic guanosine monophosphate (cGMP) increased chemoattraction to snail mucus, suggesting that the protein kinase EGL-4 may be responsible for Phasmarhabditis sp. chemoattraction.
Fe-sulphate-rich evaporative mineral precipitates from the Río Tinto, southwest Spain
- T. Buckby, S. Black, M. L. Coleman, M. E. Hodson
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- Journal:
- Mineralogical Magazine / Volume 67 / Issue 2 / April 2003
- Published online by Cambridge University Press:
- 05 July 2018, pp. 263-278
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The soluble metal sulphate salts melanterite, rozenite, rhomboclase, szomolnokite, copiapite, coquimbite, hexahydrite and halotrichite, together with gypsum, have been identified, some for the first time, on the banks of the Rio Tinto, SW Spain. Secondary Fe-sulphate minerals can form directly from evaporating, acid, sulphate-rich solutions as a result of pyrite oxidation. Chemical analyses of mixtures of these salt minerals indicate concentrations of Fe (up to 31 wt.%), Mg (up to 4 wt.%), Cu (up to 2 wt.%) and Zn (up to 1 wt.%). These minerals are shown to act as transient storage for metals and can store on average up to 10% (9.5 — 11%) and 22% (20—23%), Zn and Cu respectively, of the total discharge of the Rio Tinto during the summer period.
Melanterite and rozenite precipitates at Rio Tinto are only found in association with very acidic drainage waters (pH <1.0) draining directly from pyritic waste piles. Copiapite precipitates abundantly on the banks of the Rio Tinto by (1) direct evaporation of the river water; or (2) as part of a paragenetic sequence with the inclusion of minor halotrichite, indicating natural dehydration and decomposition. The natural occurrences are comparable with the process of paragenesis from the evaporation of Rio Tinto river water under laboratory experiments resulting in the formation of aluminocopiapite, halotrichite, coquimbite, voltaite and gypsum.
Monolayer-enriched production of Au-decorated WS2 Nanosheets via Defect Engineering
- Jeremy R. Dunklin, Paul Lafargue, Thomas M. Higgins, Gregory T. Forcherio, Mourad Benamara, Niall McEvoy, D. Keith Roper, Jonathan N. Coleman, Yana Vaynzof, Claudia Backes
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- Journal:
- MRS Advances / Volume 3 / Issue 41 / 2018
- Published online by Cambridge University Press:
- 06 April 2018, pp. 2435-2440
- Print publication:
- 2018
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Layered transition metal dichalcogenides (TMDs) represent a diverse, emerging source of two-dimensional (2D) nanostructures with broad application in optoelectronics and energy. Chemical functionalization has evolved into a powerful tool to tailor properties of these 2D TMDs; however, functionalization strategies have been largely limited to the metallic 1T-polytype. The work herein illustrates that 2H-semiconducting liquid-exfoliated tungsten disulfide (WS2) undergoes a spontaneous redox reaction with gold (III) chloride (AuCl3). Au nanoparticles (NPs) predominantly nucleate at nanosheet edges with tuneable NP size and density. AuCl3 is preferentially reduced on multi-layer WS2 and resulting large Au aggregates are easily separated from the colloidal dispersion by simple centrifugation. This process may be exploited to enrich the dispersions in laterally large, monolayer nanosheets. It is proposed that thiol groups at edges and defects sides reduce the AuCl3 to Au0 and are in turn oxidized to disulfides. Optical emission, i.e. photoluminescence, of the monolayers remained pristine, while the electrocatalytic activity towards the hydrogen evolution reaction is significantly improved. Taken together, these improvements in functionalization, fabrication, and catalytic activity represent an important advance in the study of these emerging 2D nanostructures.
A numerical study of a weakly stratified turbulent wake
- J. A. Redford, T. S. Lund, G. N. Coleman
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- Journal:
- Journal of Fluid Mechanics / Volume 776 / 10 August 2015
- Published online by Cambridge University Press:
- 13 July 2015, pp. 568-609
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Direct numerical simulation (DNS) of a time-developing turbulent wake evolving in a stably stratified background is presented. A large initial Froude number is chosen to allow the wake to become fully turbulent and axisymmetric before stratification affects the spreading rate of the mean defect. Turbulence statistics are formed by averaging over the homogeneous streamwise direction of a domain that is larger than earlier stratified-wake simulations in order to reduce the statistical uncertainty. The DNS results are used to cast light on the mechanisms that lead to the various states of this flow – namely the three-dimensional (essentially unstratified), non-equilibrium (or ‘wake-collapse’) and quasi-two-dimensional (or ‘two-component’) regimes, previously observed for wakes embedded in both weakly and strongly stratified backgrounds. For this relatively high-initial-Reynolds- and Froude-number simulation, we find that the signature reduction in the rate of decay of the maximum mean defect velocity during the wake-collapse regime is due to buoyancy-induced alterations of the turbulence structure, which weaken and redistribute the Reynolds shear stresses whose gradients appear in the streamwise mean momentum equation. The change in the rate of decay of the turbulence kinetic energy (TKE) observed during the wake-collapse regime (which occurs well after the mean velocity decay reduction begins) is not caused by transfer of turbulent gravitational potential energy to TKE, as has been previously suggested. The results instead reveal that the reduction in TKE decay – which for this flow, with its relatively weak internal waves, eventually leads to TKE growth, heralding the arrival of the two-component regime – is caused by an increase in the rate of TKE production associated with the wake structure becoming increasingly two-dimensional, such that the lateral Reynolds shear stress, $-\overline{u^{\prime }v^{\prime }}$, becomes dominant. The present results are also compared with those of previous simulations at different Froude and Reynolds numbers, and whose initial conditions contain different turbulence structures. This comparison confirms a strong degree of commonality in the late-wake behaviour, which lends support to the hypothesis that all wakes in stably stratified environments achieve a universal state in the final stages of decay.
Contributors
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- By Jon Altman, Nicholas Biddle, Jeff Borland, Matthew Butlin, William Coleman, Robert Dixon, Henry Ergas, Lionel Frost, David Greasley, Edwyna Harris, Tim Hatton, Boyd Hunter, Diane Hutchinson, Michael Keating, Monica Keneley, Christopher Lloyd, Peter J. Lloyd, Rodney Maddock, Jakob B. Madsen, Gary B. Magee, David Meredith, David T. Merrett, Deborah Oxley, Jonathan Pincus, Richard Pomfret, Andrew Seltzer, Martin P. Shanahan, Simon Ville, John K. Wilson, Glenn Withers Ao Fassa
- Edited by Simon Ville, University of Wollongong, New South Wales, Glenn Withers, Australian National University, Canberra
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- The Cambridge Economic History of Australia
- Published online:
- 05 September 2014
- Print publication:
- 08 October 2014, pp ix-xi
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Fundraising, celebrations and classroom rewards are substantial sources of unhealthy foods and beverages on public school campuses
- Susan L Caparosa, Maggie Shordon, Asherlev T Santos, Magdalena E Pomichowski, David A Dzewaltowski, Karen J Coleman
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- Journal:
- Public Health Nutrition / Volume 17 / Issue 6 / June 2014
- Published online by Cambridge University Press:
- 14 June 2013, pp. 1205-1213
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Objective
The emphasis in school nutrition policy has been on vending and competitive items. Our study was designed to characterize and quantify the amount and source of other foods and beverages on school campuses.
DesignA cross-sectional observational study was conducted using a specially designed objective nutrition observation system.
SettingOne low-income school district in southern California with six elementary and two middle schools.
SubjectsData were not collected from individual children. A total of 4033 students, 42 % of whom were Hispanic/Latino, 26 % African American and 21 % non-Hispanic white, were observed across school settings.
ResultsData were collected continuously from 9 January 2008 to 16 June 2010. Healthy foods had, per serving, total energy ≤732 kJ (≤175 kcal), total fat content ≤35 %, total saturated fat ≤10 %, sugar less ≤15 g, sodium <200 mg and trans-fat ≤0·5 g. Healthy beverages were only 100 % juice or water, and unflavoured non-fat, 1 %, 2 % milk and soya or rice milk. The system had high inter-rater reliability (r = 0·78 to 0·99), percentage agreement (83 % to 100 %) and test–retest reliability (r = 0·81 to 0·98). Significantly more unhealthy foods and beverages than healthy items were observed on all campuses (P < 0·001). An average of 1·26 (sd 0·46) items per student per week was found with an average of 0·86 (sd 0·34) unhealthy items per child per week.
ConclusionsThere were substantial amounts of unhealthy foods and beverages brought onto campuses for classroom rewards, celebrations and fundraising that should be targeted for intervention.
Credit Derivatives. Prepared by the Derivatives Working Party of the Faculty and Institute of Actuaries
- M. J. Muir, A. Chase, P. S. Coleman, P. Cooper, G. S. Finkelstein, P. Fulcher, C. Harvey, F. R. Pereira, A. Shamash, T. J. D. Wilkins
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- Journal:
- British Actuarial Journal / Volume 13 / Issue 2 / 01 July 2007
- Published online by Cambridge University Press:
- 10 June 2011, pp. 185-236
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This paper was written by the Derivatives Working Party, a permanent working party of the Life Research Committee of the Institute and Faculty of Actuaries. Our aim is to consider how life assurers may use, or may wish to use, derivatives, and if their use is unduly constrained, e.g. by regulation. This paper focuses on credit derivatives. We provide an overview of the credit derivatives market, and the strong growth in this market over recent years. We then focus on the two main traded credit derivative instruments — Credit Default Swaps (CDSs) and Collateralised Debt Obligations (CDOs). We explain how these instruments work and are priced, and clarify some of the more complex topics involved, such as the settlement of CDSs, basis risk and the relevance of implied correlation in pricing CDOs. We then consider how life insurers could make use of credit derivatives, for example to provide more efficient investment management in taking exposure to credit risk, or to hedge credit exposures, and consider the regulatory implications of so doing. Finally, in the Appendix, we discuss the credit spread puzzle, and the existence or otherwise of a liquidity premium in corporate bond spreads, with implications for the valuation of illiquid liabilities.
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- By Rose Teteki Abbey, K. C. Abraham, David Tuesday Adamo, LeRoy H. Aden, Efrain Agosto, Victor Aguilan, Gillian T. W. Ahlgren, Charanjit Kaur AjitSingh, Dorothy B E A Akoto, Giuseppe Alberigo, Daniel E. Albrecht, Ruth Albrecht, Daniel O. Aleshire, Urs Altermatt, Anand Amaladass, Michael Amaladoss, James N. Amanze, Lesley G. Anderson, Thomas C. Anderson, Victor Anderson, Hope S. Antone, María Pilar Aquino, Paula Arai, Victorio Araya Guillén, S. Wesley Ariarajah, Ellen T. Armour, Brett Gregory Armstrong, Atsuhiro Asano, Naim Stifan Ateek, Mahmoud Ayoub, John Alembillah Azumah, Mercedes L. García Bachmann, Irena Backus, J. Wayne Baker, Mieke Bal, Lewis V. Baldwin, William Barbieri, António Barbosa da Silva, David Basinger, Bolaji Olukemi Bateye, Oswald Bayer, Daniel H. Bays, Rosalie Beck, Nancy Elizabeth Bedford, Guy-Thomas Bedouelle, Chorbishop Seely Beggiani, Wolfgang Behringer, Christopher M. Bellitto, Byard Bennett, Harold V. Bennett, Teresa Berger, Miguel A. Bernad, Henley Bernard, Alan E. Bernstein, Jon L. Berquist, Johannes Beutler, Ana María Bidegain, Matthew P. Binkewicz, Jennifer Bird, Joseph Blenkinsopp, Dmytro Bondarenko, Paulo Bonfatti, Riet en Pim Bons-Storm, Jessica A. Boon, Marcus J. Borg, Mark Bosco, Peter C. Bouteneff, François Bovon, William D. Bowman, Paul S. Boyer, David Brakke, Richard E. Brantley, Marcus Braybrooke, Ian Breward, Ênio José da Costa Brito, Jewel Spears Brooker, Johannes Brosseder, Nicholas Canfield Read Brown, Robert F. Brown, Pamela K. Brubaker, Walter Brueggemann, Bishop Colin O. Buchanan, Stanley M. Burgess, Amy Nelson Burnett, J. Patout Burns, David B. Burrell, David Buttrick, James P. Byrd, Lavinia Byrne, Gerado Caetano, Marcos Caldas, Alkiviadis Calivas, William J. Callahan, Salvatore Calomino, Euan K. Cameron, William S. Campbell, Marcelo Ayres Camurça, Daniel F. Caner, Paul E. Capetz, Carlos F. Cardoza-Orlandi, Patrick W. Carey, Barbara Carvill, Hal Cauthron, Subhadra Mitra Channa, Mark D. 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Flowers, Carole Fontaine, David Ford, Mary Ford, Stephanie A. Ford, Jim Forest, William Franke, Robert M. Franklin, Ruth Franzén, Edward H. Friedman, Samuel Frouisou, Lorelei F. Fuchs, Jojo M. Fung, Inger Furseth, Richard R. Gaillardetz, Brandon Gallaher, China Galland, Mark Galli, Ismael García, Tharscisse Gatwa, Jean-Marie Gaudeul, Luis María Gavilanes del Castillo, Pavel L. Gavrilyuk, Volney P. Gay, Metropolitan Athanasios Geevargis, Kondothra M. George, Mary Gerhart, Simon Gikandi, Maurice Gilbert, Michael J. Gillgannon, Verónica Giménez Beliveau, Terryl Givens, Beth Glazier-McDonald, Philip Gleason, Menghun Goh, Brian Golding, Bishop Hilario M. Gomez, Michelle A. Gonzalez, Donald K. Gorrell, Roy Gottfried, Tamara Grdzelidze, Joel B. Green, Niels Henrik Gregersen, Cristina Grenholm, Herbert Griffiths, Eric W. Gritsch, Erich S. Gruen, Christoffer H. Grundmann, Paul H. Gundani, Jon P. Gunnemann, Petre Guran, Vidar L. Haanes, Jeremiah M. 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- Edited by Daniel Patte, Vanderbilt University, Tennessee
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- The Cambridge Dictionary of Christianity
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- 05 August 2012
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- 20 September 2010, pp xi-xliv
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The instability of a vortex ring impinging on a free surface
- P. J. ARCHER, T. G. THOMAS, G. N. COLEMAN
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- Journal of Fluid Mechanics / Volume 642 / 10 January 2010
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- 04 December 2009, pp. 79-94
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Direct numerical simulation is used to study the development of a single laminar vortex ring as it impinges on a free surface directly from below. We consider the limiting case in which the Froude number approaches zero and the surface can be modelled with a stress-free rigid and impermeable boundary. We find that as the ring expands in the radial direction close to the surface, the natural Tsai–Widnall–Moore–Saffman (TWMS) instability is superseded by the development of the Crow instability. The Crow instability is able to further amplify the residual perturbations left by the TWMS instability despite being of differing radial structure and alignment. This occurs through realignment of the instability structure and shedding of a portion of its outer vorticity profile. As a result, the dominant wavenumber of the Crow instability reflects that of the TWMS instability, and is dependent upon the initial slenderness ratio of the ring. At higher Reynolds number a short-wavelength instability develops on the long-wavelength Crow instability. The wavelength of the short waves is found to vary around the ring dependent on the local displacement of the long waves.
Risk factors for Neisseria meningitides carriage in a school during a community outbreak of meningococcal infection
- A. L. Davies, D. O'Flanagan, R. L. Salmon, T. J. Coleman
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- Epidemiology & Infection / Volume 117 / Issue 2 / October 1996
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- 15 May 2009, pp. 259-266
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As part of the management of an outbreak of meningococcal infection, 119 school contacts of an index case were swabbed for nasopharyngeal carriage. In a cohort study, risk factors for Neisseria meningitidis carriage were ascertained by means of a questionnaire, completed by 114 (96%) of those swabbed.
Twenty five (21%) cultures were identified as ‘neisseria positive’; of which there were 18 (15%) Neisseria meningitidis isolates, 2 (2%) Neisseria lactamica isolates and 5 (4%) showed contaminants only. Two (2%) carriers were identified as harbouring the implicated outbreak strain. Single variable analysis identified six statistically significant risk factors for meningococcal carriage; increasing age, female sex, manual social class, personal smoking, regular attendance at a discotheque and rhinorrhoea. Multivariate analysis, using logistic regression modelling, found that of these six variables only age, sex and social class remained statistically significant when the other factors were controlled for. Nevertheless the role of smoking, social events and respiratory/viral infections in nasopharyngeal carriage, and other plausible mechanisms whereby age, sex and social class might exert their effect, could usefully be investigated further.