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C D Cooper

Publications and source records attributed to C D Cooper.

11 recordsLinked to original sources
PubMed2005

Quantum level structures at a Fermi resonance with angular momentum: classical periodic orbits, catastrophe maps and quantum monodromy.

The Xiao-Kellman catastrophe map, for the classification of classical periodic orbits of the standard 2:1 Fermi resonance Hamiltonian is extended to species with finite vibrational angular momentum. The influence of the classical periodic orbit structure on different organizations of the quantum mechanical eigenvalues, in the four regions of the map, is strikingly demonstrated. The quantum eigenvalue lattices in angular momentum and energy space show dislocations attributable to a topological effect, termed quantum monodromy. Analogues with quantum monodromy in quasi-linear molecules and LiCN/LiNC isomerisation are demonstrated.

Cyanides↗
PubMed2005

Playground safety in South Western Sydney.

OBJECTIVE: Recognition of the cost of injuries sustained in playgrounds has led to the development of Australian/New Zealand Standards for playground safety. This study assesses compliance of public playgrounds in South Western Sydney with the current Standards. METHODS: Playgrounds in South Western Sydney were randomly audited for compliance with Australian/New Zealand Standards for playground equipment pertaining to fall height, type of undersurface material, adequacy of maintenance of undersurface materials and adequacy of the safe fall zone. Comparisons were made with an audit of playgrounds in New South Wales undertaken in 1995 by Kidsafe. RESULTS: Of the 257 pieces of equipment from 87 playgrounds audited, only three (3.4%) playgrounds and 65 (25.3%) pieces of equipment complied with all criteria assessed. Compared with the 1995 study, there has been a significant improvement in equipment complying with height standards (84.4% vs 72.2%, P < 0.0001) and appropriate undersurface material (66.8% vs 45.4%, P < 0.0001). Pinebark is now the most common appropriate undersurface material used but is poorly maintained, particularly in high-traffic areas. Of 131 pieces of equipment with an appropriate undersurface material, only 38 (29%) had an adequate safe fall zone. CONCLUSIONS: Improvements in playground safety have occurred; however, very few playgrounds meet the Australian/New Zealand Standards. Compliance with Standards pertaining to maintenance of undersurface materials and safe fall zone is poor. Mechanisms need to be developed to support councils in the upgrading and maintenance of existing playgrounds.

Accident Prevention↗
PubMed2003

Barriers to immunization: attitudes of general practitioners to varicella, the disease and its vaccine.

OBJECTIVES: To investigate the attitudes of general practitioners (GPs) to varicella disease and varicella vaccine. METHODS: A cross-sectional questionnaire was mailed to GPs in Fairfield (located in the south-western suburbs of Sydney, NSW, Australia) to identify attitudes about varicella vaccine, previous experience with varicella disease and the likelihood of prescribing varicella vaccine. RESULTS: Of 239 questionnaires issued, 160 were returned (67%). The majority (72%) of respondents agreed that varicella vaccine should become part of the immunization schedule. However 12% of GPs did not support vaccination for varicella as they considered it to be a benign self-limiting disease. Respondents who had experience with varicella complications were significantly more likely to recommend universal vaccination (OR 3.36; 95% confidence interval (CI) 1.38-8.19) whereas those respondents who were concerned about side effects of the vaccine were less likely to recommend universal vaccination (OR 0.31; CI 0.15-0.63). CONCLUSIONS: The majority of GPs are receptive to varicella vaccination becoming part of the immunization schedule. Experience with varicella complications is associated with recommending universal varicella vaccination. General practitioners in this cohort do not consider varicella to be a benign disease, but they are concerned about possible unknown side effects of the vaccine. Public health measures for introducing universal vaccination need to address these concerns.

Attitude of Health Personnel↗
PubMed2001

Evidence for recent climate change on Mars from the identification of youthful near-surface ground ice.

Ground ice in the crust and soil may be one of the largest reservoirs of water on Mars. Near-surface ground ice is predicted to be stable at latitudes higher than 40 degrees (ref. 4), where a number of geomorphologic features indicative of viscous creep and hence ground ice have been observed. Mid-latitude soils have also been implicated as a water-ice reservoir, the capacity of which is predicted to vary on a 100,000-year timescale owing to orbitally driven variations in climate. It is uncertain, however, whether near-surface ground ice currently exists at these latitudes, and how it is changing with time. Here we report observational evidence for a mid-latitude reservoir of near-surface water ice occupying the pore space of soils. The thickness of the ice-occupied soil reservoir (1-10 m) and its distribution in the 30 degrees to 60 degrees latitude bands indicate a reservoir of (1.5-6.0) x 104 km3, equivalent to a global layer of water 10-40 cm thick. We infer that the reservoir was created during the last phase of high orbital obliquity less than 100,000 years ago, and is now being diminished.

Climate↗
PubMed2000

Analysis of connexin phosphorylation sites.

Most connexins, the proteins that form gap junction channels, are phosphoproteins. Connexin phosphorylation has been thought to regulate gap junctional protein trafficking, gap junction assembly, channel gating, and turnover. Connexin phosphorylation has been investigated in a variety of ways. Some connexins show mobility shifts in sodium dodecyl sulfate-polyacrylamide gel electrophoresis on phosphorylation. Kinase modulators can change the level of connexin phosphorylation and affect gap junctional communication levels. Metabolic labeling of cultured cells has allowed both phosphoamino acid identification and generation of phosphotryptic peptide maps. However, identification of the location of phosphorylated residues within the connexin sequence has required either targeted peptide synthesis, in vitro phosphorylation of known sites, and two-dimensional comigration studies or liquid chromatographic separation and N-terminal sequencing of peptides. In addition to these conventional methods, we discuss new applications of mass spectrometry to the identification of phosphorylated peptides and the specific residues phosphorylated within the connexin-derived peptide.

Amino Acid Sequence↗
PubMed1999

Evaluating photoscreeners II: MTI and fortune videorefractor.

BACKGROUND: Amblyopia is a public health problem, usually amenable to treatment if detected early. Photoscreeners are camera-based instruments which can detect risk factors for amblyopia such as squint, refractive errors and media opacities. OBJECTIVE: To evaluate two commercially available photoscreeners, namely the MTI photoscreener (Medical Technology, Iowa City, IA, USA) and the Fortune Optical VRB-100 (Fortune Optical, Padova, Italy) videophotorefractor, in a selected childhood population, having a high prevalence of amblyopia, before undertaking a full-scale trial in the general population. SUBJECTS AND METHODS: The study design was a double-masked study. One-hundred and five children aged between 12 and 44 months with either normal vision or known visual disorders were photoscreened without cycloplegia using the Fortune and the MTI photoscreeners. Each child had a full ophthalmic examination either on the day of screening or in the preceding 6 months. Risk factors were: any manifest strabismus (squint), hypermetropia >3.5 D, anisometropia > or =1 D sphere, myopia > or =2 D sphere, astigmatism > or =2 D, media opacity or fundus abnormality affecting vision. The prevalence of risk factors for amblyopia was 60%. Photoscreen images were reviewed by two independent masked observers for indicators of amblyopiogenic risk factors and compared to the full ophthalmological examination to determine sensitivity and specificity for each instrument. RESULTS: Sensitivities and specificities for the detection of risk factors for amblyopia were as follows. Fortune photoscreener: reader 1, sensitivity 60%, specificity 75%; reader 2, sensitivity 68% specificity 86%. MTI photoscreener: reader 1, sensitivity 56%, specificity 79%; reader 2, sensitivity 61%, sensitivity 86%. The results for reader 1 and 2 showed no significant differences for either instrument. CONCLUSION: Both instruments performed unsatisfactorily in a study population aged 1-4 years with a high prevalence of amblyopiogenic risk factors. Accordingly, we do not believe that either instrument can be recommended to screen for eye disorders in children between the ages of 1 and 4 years because the low prevalence of amblyopia in this population demands very high sensitivity and specificity in order to avoid inappropriate over- or under-referral.

Amblyopia↗
PubMed1996

Evaluation of photoscreener instruments in a childhood population. 1. Otago photoscreener and Dortmans videophotorefractor.

OBJECTIVE: To evaluate two photoscreeners in a childhood population. STUDY DESIGN: Double-masked study. SUBJECTS AND METHOD: One hundred and thirteen children aged between 11 and 44 months with either normal vision or known visual disorders were photoscreened without cycloplegia by the Otago and Dortmans (prototype) photoscreeners. Each child had a full ophthalmological examination either on the day of screening or in the proceeding six months. Photoscreen images were reviewed by an independent observer for indicators of amblyopiogenic risk factors, and compared to the full ophthalmological examination to determine sensitivity and specificity for each instrument. RESULTS: The Otago photoscreener returned a sensitivity of 70% and specificity of 82% for the detection of amblyopiogenic risk factors. The Dortmans photoscreener returned a sensitivity of 70% and specificity of 90%. Both photoscreeners were portable and easily operated. CONCLUSION: Children can be screened successfully for amblyopiogenic risk factors with these photoscreening systems. Further evaluation is required to determine specificity in a normal population. This would also provide information on the potential usefulness of photoscreeners in a cost effective childhood vision screening program.

Amblyopia↗
PubMedDate not supplied

Serum leptin and leptin binding activity in children and adolescents with hypothalamic dysfunction.

Marked disturbance in eating behaviour and obesity are common sequelae of hypothalamic damage. To investigate whether these were associated with dysfunctional leptin central feedback, we evaluated serum leptin and leptin binding activity in 37 patients (age 3.5-21 yr) with tumour or trauma involving the hypothalamic-pituitary axis compared with 138 healthy children (age 5.0-18.2 yr). Patients were subdivided by BMI <2 SDS or > or = 2 SDS and healthy children and children with simple obesity of comparable age and pubertal status served as controls. Patients had higher BMI (mean 1.9 vs 0.2 SDS; p <0.001), a greater proportion had BMI > or = 2 SDS (54% vs 8%; p <0.001) and higher serum leptin (mean 2.1 vs 0.04 SDS; p <0.001) than healthy children. Serum leptin (mean 1.1 vs -0.1 SDS; p = 0.004) and values adjusted for BMI (median 0.42 vs 0.23 microg/l:kg/m2; p = 0.02) were higher in patients with BMI <2 SDS. However, serum leptin adjusted for BMI was similar in patients with BMI > or = 2 SDS compared to corresponding controls (1.08 vs 0.95; p = 0.6). Log serum leptin correlated with BMI SDS in all subject groups but the relationship in patients with BMI <2 SDS was of higher magnitude (r = 0.65, slope = 0.29, p =0.05 for difference between slopes) than in healthy controls (r = 0.42, slope = 0.19). Serum leptin binding activity (median 7.5 vs 9.3%; p = 0.02) and values adjusted for BMI (median 0.28 vs 0.48 % x m2/kg; p <0.001) were lower in patients than in healthy children. The markedly elevated leptin levels with increasing BMI in non-obese patients with hypothalamic-pituitary damage are suggestive of an unrestrained pattern of leptin secretion. This along with low leptin binding activity and hence higher free leptin levels would be consistent with central leptin insensitivity.

Adipose Tissue↗