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Search Results: 1 - 10 of 305804 matches for " Elizabeth J. Hamilton "
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Otitis media in young Aboriginal children from remote communities in Northern and Central Australia: a cross-sectional survey
Peter S Morris, Amanda J Leach, Peter Silberberg, Gabrielle Mellon, Cate Wilson, Elizabeth Hamilton, Jemima Beissbarth
BMC Pediatrics , 2005, DOI: 10.1186/1471-2431-5-27
Abstract: 709 Aboriginal children aged 6–30 months living in 29 communities from 4 health regions participated in the study between May and November 2001. Otitis media (OM) and perforation of the tympanic membrane (TM) were diagnosed by tympanometry, pneumatic otoscopy, and video-otoscopy. We used otoscopic criteria (bulging TM or recent perforation) to diagnose acute otitis media.914 children were eligible to participate in the study and 709 were assessed (78%). Otitis media affected nearly all children (91%, 95%CI 88, 94). Overall prevalence estimates adjusted for clustering by community were: 10% (95%CI 8, 12) for unilateral otitis media with effusion (OME); 31% (95%CI 27, 34) for bilateral OME; 26% (95%CI 23, 30) for acute otitis media without perforation (AOM/woP); 7% (95%CI 4, 9) for AOM with perforation (AOM/wiP); 2% (95%CI 1, 3) for dry perforation; and 15% (95%CI 11, 19) for chronic suppurative otitis media (CSOM). The perforation prevalence ranged from 0–60% between communities and from 19–33% between regions. Perforations of the tympanic membrane affected 40% of children in their first 18 months of life. These were not always persistent.Overall, 1 in every 2 children examined had otoscopic signs consistent with suppurative ear disease and 1 in 4 children had a perforated tympanic membrane. Some of the children with intact tympanic membranes had experienced a perforation that healed before the survey. In this high-risk population, high rates of tympanic perforation were associated with high rates of bulging of the tympanic membrane.Middle ear disease (otitis media) is common and frequently severe in Australian Aboriginal children [1,2] In the worst affected communities, perforation of the tympanic membrane (TM) may affect more than 50% of children [3,4]. Such high rates have not been described consistently in any other population in the world.We have previously reported the early onset of otitis media with effusion (OME) within the first few weeks of life in a remot
Foucault’s Concept of “Local Knowledges” for Researching Nursing Practice
Aporia : The Nursing Journal , 2009,
Abstract: Nursing knowledge is diversely represented and contested, among academics and clinicians within and outside of nursing. This paper explores several Foucauldian concepts in relation to subjugated, local, na ve and situated forms of knowledge. We argue that these concepts relate closely to the mundane world of nursing and are useful for thinking about, teaching and researching everyday nursing practice. The discussion is tied back to data and analysis from a postmodern ethnography of nurses’ assessment practice in an Australian acute psychiatric setting. We show how Foucauldian analysis of nurses’ knowledge can usefully foreground taken-for-granted aspects of skillful practice.
The Influence of Social Structure, Habitat, and Host Traits on the Transmission of Escherichia coli in Wild Elephants
Patrick I. Chiyo, Laura E. Grieneisen, George Wittemyer, Cynthia J. Moss, Phyllis C. Lee, Iain Douglas-Hamilton, Elizabeth A. Archie
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093408
Abstract: Social structure is proposed to influence the transmission of both directly and environmentally transmitted infectious agents. However in natural populations, many other factors also influence transmission, including variation in individual susceptibility and aspects of the environment that promote or inhibit exposure to infection. We used a population genetic approach to investigate the effects of social structure, environment, and host traits on the transmission of Escherichia coli infecting two populations of wild elephants: one in Amboseli National Park and another in Samburu National Reserve, Kenya. If E. coli transmission is strongly influenced by elephant social structure, E. coli infecting elephants from the same social group should be genetically more similar than E. coli sampled from members of different social groups. However, we found no support for this prediction. Instead, E. coli was panmictic across social groups, and transmission patterns were largely dominated by habitat and host traits. For instance, habitat overlap between elephant social groups predicted E. coli genetic similarity, but only in the relatively drier habitat of Samburu, and not in Amboseli, where the habitat contains large, permanent swamps. In terms of host traits, adult males were infected with more diverse haplotypes, and males were slightly more likely to harbor strains with higher pathogenic potential, as compared to adult females. In addition, elephants from similar birth cohorts were infected with genetically more similar E. coli than elephants more disparate in age. This age-structured transmission may be driven by temporal shifts in genetic structure of E. coli in the environment and the effects of age on bacterial colonization. Together, our results support the idea that, in elephants, social structure often will not exhibit strong effects on the transmission of generalist, fecal-oral transmitted bacteria. We discuss our results in the context of social, environmental, and host-related factors that influence transmission patterns.
Morphologies of low-redshift AGN host galaxies: what role does AGN luminosity play?
Carolin Villforth,Fred Hamann,Anton Koekemoer,David Rosario,Timothy Hamilton,Elizabeth J. McGrath,Arjen van der Wel,YuYen Chang,Yicheng Guo,CANDELS collaboration
Physics , 2013,
Abstract: Mergers of galaxies have been suspected to be a major trigger of AGN activity for many years. However, when compared to carefully matched control samples, AGN host galaxies often show no enhanced signs of interaction. A common explanation for this lack of observed association between AGN and mergers has often been that while mergers are of importance for triggering AGN, they only dominate at the very high luminosity end of the AGN population. In this study, we compare the morphologies of AGN hosts to a carefully matched control sample and particularly study the role of AGN luminosity. We find no enhanced merger rates in AGN hosts and also find no trend for stronger signs of disturbance at higher AGN luminosities. While this study does not cover very high luminosity AGN, we can exclude a strong connection between AGN and mergers over a wide range of AGN luminosities and therefore for a large part of the AGN population.
Silencing of Claudin-11 Is Associated with Increased Invasiveness of Gastric Cancer Cells
Rachana Agarwal,Yuriko Mori,Yulan Cheng,Zhe Jin,Alexandru V. Olaru,James P. Hamilton,Stefan David,Florin M. Selaru,Jian Yang,John M. Abraham,Elizabeth Montgomery,Patrice J. Morin,Stephen J. Meltzer
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008002
Abstract: Claudins are membrane proteins that play critical roles in tight junction (TJ) formation and function. Members of the claudin gene family have been demonstrated to be aberrantly regulated, and to participate in the pathogenesis of various human cancers. In the present study, we report that claudin-11 (CLDN11) is silenced in gastric cancer via hypermethylation of its promoter region.
The Valuable Role of Endoscopy in Inflammatory Bowel Disease
Matthew J. Hamilton
Diagnostic and Therapeutic Endoscopy , 2012, DOI: 10.1155/2012/467979
Abstract: Endoscopy is a valuable clinical tool for the clinician who takes care of patients with inflammatory bowel disease (IBD). The role of endoscopy in the diagnosis, management, and treatment of IBD is discussed in this review. The central role that colonoscopy plays in screening for colon cancer in patients with longstanding IBD is also addressed. 1. Introduction Endoscopy is an essential clinical tool to assist in the diagnosis and management of inflammatory bowel disease (IBD) [1]. By direct visual inspection of the intestinal mucosa used in conjunction with histology from biopsies, a diagnosis of IBD can be made. Proper use of endoscopy with biopsies also enables evaluation of other disorders that may mimic the gastrointestinal features of IBD. Once the diagnosis of IBD is made, endoscopy is performed to assess the severity and location of inflammation, and to evaluate for other disease possibilities in the midst of a flare. Response to medical treatment or surveillance for postoperative disease recurrence may also be evaluated. Finally, endoscopy is used in colon cancer surveillance in those with longstanding IBD. The role of endoscopy in these areas will be reviewed in this paper. The emerging role of wireless capsule endoscopy and endoscopic ultrasound in IBD will not be addressed. 2. Endoscopy in the Diagnosis of IBD Because IBD is a chronic lifelong condition that requires careful medical management and followup and can be associated with significant morbidity with hospitalizations and surgeries, establishing that the diagnosis is essential. Once IBD is suspected based on clinical signs and symptoms, laboratory, and/or radiology studies, endoscopy with mucosal biopsies adds considerably to the diagnosis [2, 3]. The index colonoscopy is critical in establishing the disease extent and severity. Special note must be made of the perianal area for tags, fissures, strictures, and fistula tract openings which may suggest Crohn’s disease (CD). The rectal mucosa must be carefully inspected and biopsied to evaluate for at least microscopic inflammation as involvement here is always present in ulcerative colitis (UC) [4]. Close attention to the mucosal features seen throughout the colon can help suggest IBD and even decipher between UC and CD. Sensitive endoscopic features to establish a diagnosis of CD are patchiness of the disease extent, apthous ulcers (Figure 1(a)), and cobblestoning [3] (Figure 1(b)). It is the penetrating nature into the deeper layers of the colon wall that can sometimes give the characteristic cobblestoning appearance. The discrete
Towards Optimal Measurement of Power Spectra II: A Basis of Positive, Compact, Statistically Orthogonal Kernels
A. J. S. Hamilton
Physics , 1997, DOI: 10.1093/mnras/289.2.295
Abstract: This is the second of two papers which address the problem of measuring the unredshifted power spectrum of fluctuations from a galaxy survey in optimal fashion. A key quantity is the Fisher matrix, which is the inverse of the covariance matrix of minimum variance estimators of the power spectrum of the survey. It is shown that bases of kernels which give rise to complete sets of statistically orthogonal windowed power spectra are obtained in general from the eigenfunctions of the Fisher matrix scaled by some arbitrary positive definite scaling matrix. Among the many possible bases of kernels, there is a basis, obtained by applying an infinitely steep scaling function, which leads to kernels which are positive and compact in Fourier space. This basis of kernels, along with the associated minimum variance pair weighting derived in the previous paper, would appear to offer a solution to the problem of how to measure the unredshifted power spectrum optimally. Illustrative kernels are presented for the case of the PSCz survey.
Towards Optimal Measurement of Power Spectra I: Minimum Variance Pair Weighting and the Fisher Matrix
A. J. S. Hamilton
Physics , 1997, DOI: 10.1093/mnras/289.2.285
Abstract: This is the first of a pair of papers which address the problem of measuring the unredshifted power spectrum in optimal fashion from a survey of galaxies, with arbitrary geometry, for Gaussian or non-Gaussian fluctuations, in real or redshift space. In this first paper, that pair weighting is derived which formally minimizes the expected variance of the unredshifted power spectrum windowed over some arbitrary kernel. The inverse of the covariance matrix of minimum variance estimators of windowed power spectra is the Fisher information matrix, which plays a central role in establishing optimal estimators. Actually computing the minimum variance pair window and the Fisher matrix in a real survey still presents a formidable numerical problem, so here a perturbation series solution is developed. The properties of the Fisher matrix evaluated according to the approximate method suggested here are investigated in more detail in the second paper.
Redshift Distortions and Omega in IRAS Surveys
A. J. S. Hamilton
Physics , 1995,
Abstract: Redshift space distortions on large scales can be used to measure the linear growth rate parameter $\ff \approx \Omega^{0.6}/b$. I report here measurements of such distortions in the IRAS 2 Jy, 1.2 Jy, and QDOT redshift surveys, finding $\ff = 0.69^{+ .21}_{- .19}$ from a merged QDOT plus 1.2 Jy catalogue. Unfortunately, confidence in this result is undermined by a marked ($4\sigma$) change in the pattern of clustering in QDOT beyond about $80 h^{-1} Mpc$. A similar effect may be present at a mild level in the 1.2 Jy survey. The effect may be caused by systematic variation in the effective flux limit of the IRAS PSC over the sky, with a dispersion of $\sim 0.1$ Jy on scales $\sim 7^{\circ}$. If so, then the value of $\ff$ inferred from redshift distortions in IRAS surveys may be systematically underestimated.
Formulae for Growth Factors In Expanding Universes Containing Matter and a Cosmological Constant
A. J. S. Hamilton
Physics , 2000, DOI: 10.1046/j.1365-8711.2001.04137.x
Abstract: Formulae are presented for the linear growth factor D/a and its logarithmic derivative dlnD/dlna in expanding Friedmann-Robertson-Walker Universes with arbitrary matter and vacuum densities. The formulae permit rapid and stable numerical evaluation. A fortran program is available at http://casa.colorado.edu/~ajsh/growl/ .
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