A Study of Periodontal Hazards of Third Molars

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142112/1/jper0209.pd

Hamiltonians for Reduced Gravity

A generalised canonical formulation of gravity is devised for foliations of spacetime with codimension $n\ge1$. The new formalism retains n-dimensional covariance and is especially suited to 2+2 decompositions of spacetime. It is also possible to use the generalised formalism to obtain boundary contributions to the 3+1 Hamiltonian.Comment: 18 pages, revtex, 3 postscript figures include

The Neon Abundance in the Ejecta of QU Vul From Late-Epoch IR Spectra

We present ground-based SpectroCam-10 mid-infrared, MMT optical, and Spitzer Space Telescope IRS mid-infrared spectra taken 7.62, 18.75, and 19.38 years respectively after the outburst of the old classical nova QU Vulpeculae (Nova Vul 1984 #2). The spectra of the ejecta are dominated by forbidden line emission from neon and oxygen. Our analysis shows that neon was, at the first and last epochs respectively, more than 76 and 168 times overabundant by number with respect to hydrogen compared to the solar value. These high lower limits to the neon abundance confirm that QU Vul involved a thermonuclear runaway on an ONeMg white dwarf and approach the yields predicted by models of the nucleosynthesis in such events.Comment: ApJ 2007 accepted, 18 pages, including 5 figures, 1 tabl

On Visible Homelessness and the Micro-Aesthetics of Public Space

In this article, we investigate the circumstances that have produced the current municipal regulatory approach to homelessness in the City of Melbourne, Victoria, and the ways in which visibly homeless people are policed through a micro-aesthetics of their presence in public space, which involves the monitoring of their bodily demeanour and their physical possessions. Our study contributes to and draws from a range of debates, including studies of the governmental conjunction of poverty and crime, analysis of the co-implication of law and spatiality, research on the criminalisation of homelessness and homeless people, and the burgeoning criminological interest in the significance of the visual field for our understandings of crime and criminality. This article recounts how homelessness, public space and questions of aesthetics have recently coalesced in debates about the regulation of homelessness in the public space of Melbourne’s city centre. It approaches the issues through comparative consideration of genres of municipal management frameworks in other jurisdictions, detailed textual consideration of the Protocol on Homelessness in the City of Melbourne and an empirical study of visible homelessness in the public places of central Melbourne

High Resolution mid-Infrared Imaging of SN 1987A

Using the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope, we have detected and resolved 10 micron emission at the position of the inner equatorial ring (ER) of supernova SN 1987A at day 6067. ``Hot spots'' similar to those found in the optical and near-IR are clearly present. The morphology of the 10 micron emission is globally similar to the morphology at other wavelengths from X-rays to radio. The observed mid-IR flux in the region of SN1987A is probably dominated by emission from dust in the ER. We have also detected the ER at 20 micron at a 4 sigma level. Assuming that thermal dust radiation is the origin of the mid-IR emission, we derive a dust temperature of 180^{+20}_{-10} K, and a dust mass of 1.- 8. 10^{-5} Mo for the ER. Our observations also show a weak detection of the central ejecta at 10 micron. We show that previous bolometric flux estimates (through day 2100) were not significantly contaminated by this newly discovered emission from the ER. If we assume that the energy input comes from radioactive decays only, our measurements together with the current theoretical models set a temperature of 90 leq T leq 100 K and a mass range of 10^{-4} - 2. 10^{-3} Mo for the dust in the ejecta. With such dust temperatures the estimated thermal emission is 9(+/-3) 10^{35} erg s^{-1} from the inner ring, and 1.5 (+/-0.5) 10^{36} erg s^{-1} from the ejecta. Finally, using SN 1987A as a template, we discuss the possible role of supernovae as major sources of dust in the Universe.Comment: aastex502, 14 pages, 4 figures; Accepted for publication in ApJ Content changed: new observations, Referee's comments and suggestion

Intracranial Neoplasms in the First Year of Life: Results of a Third Cohort of Patients From a Single Institution

BACKGROUND: Brain tumors in the first year of life are rare and their management remains challenging. OBJECTIVE: To report on the contemporary management of brain tumors in infants with reference to previous series from our institution. METHODS: Retrospective cohort study design. Electronic/paper case note review of all brain tumors diagnosed at our institution in children aged <1 yr since the publication of our previous series. RESULTS: Ninety-eight patients were seen. The most common presentations were with vomiting and macrocrania, at a median age of 184 d. Sixty-two percent of tumors were supratentorial. Ninety-one patients underwent 230 procedures; 7 patients had no surgery. One hundred eighteen operations were directly on brain tumors (biopsy 37, subtotal resection 47, gross total resection 34). Ninety-one cerebrospinal fluid diversions, 9 endoscopic procedures, and 13 preoperative embolizations were performed. Operative mortality was 4.4%. Tumor types in order of frequency were choroid plexus papillomas (CPP, 17), primitive neuroectodermal tumor (12), atypical teratoid/rhabdoid tumor (10), high-grade glioma (9), optic glioma (9), ependymoma (8), low-grade glioma (6), pilocytic astrocytoma (6), choroid plexus carcinoma (5), and teratoma (5), with 11 miscellaneous tumors. Survival was 93% at 1 mo (91/98), 64% at 1 yr (61/95), 44% at 5 yr (32/73), 28% at 10 yr (16/58). No patients with CPP or low-grade glioma died. Five-year survival rates were lowest for anaplastic ependymoma, primitive neuroectodermal tumor, and atypical teratoid/rhabdoid tumor. Seventy-seven percent of children reaching school age were in mainstream schooling. CONCLUSION: Overall survival from neonatal brain tumors remains similar to previous series; analysis of tumor subtypes reveals improvements for CPP and gliomas. Despite increasing operative intervention, operative mortality continues to decline for this group of challenging patients

The philosophy of critical realism and childhood studies

Critical realism is a philosophy of social science that analyses and aims to remedy current problems and gaps. Basic tenets of positivist and quantitative research tend to contradict those of qualitative and interpretive research, and critical realism proposes ways to resolve the contradictions. Vital themes in childhood research that are reviewed in this article include a comparison with feminist research, critical realism, being and thought, transitive and intransitive, theory/practice consistency, agency and structure, closed and open systems, micro and macro in the global/local nexus, four planar social being, facts and values, and transformative change through the four-stage MELD dialectic. Critical realism aims to understand the world in order to be able move from coercion towards creative liberating power

Does the Mutation Type Affect the Response to Cranial Vault Expansion in Children With Apert Syndrome?

Most cases of Apert syndrome are caused by mutations in the FGFR2 gene, either Ser252Trp or Pro253Arg. In these patients, over the last decades, spring-assisted posterior vault expansion (SA-PVE) has been the technique of choice for cranial vault expansion in the Craniofacial Unit of Great Ormond Street Hospital for Children (GOSH), London. The aim of this study was to investigate if there is a difference in preoperative intracranial volume (ICV) in patients with Apert syndrome with Ser252Trp or Pro253Arg mutation and whether these mutations affect the change in ICV achieved by SA-PVE. The GOSH craniofacial SA-PVE database was used to select patients with complete genetic testing and preoperative and postoperative computed tomography scans. ICV was calculated using FSL (FMRIB Analysis Group, Oxford) and adjusted based on Apert-specific growth curves. Sixteen patients were included with 8 having Ser252Trp mutation and 8 having Pro253Arg mutation. The mean preoperative adjusted computed tomography volume for patients in the Ser252Trp group was 1137.7 cm3 and in the Pro253Arg group was 1115.8 cm3 (P=1.00). There was a significant increase in ICV following SA-PVE in all patients (P<0.001) with no difference in mean change in ICV between the groups (P=0.51). Four (50%) patients with Ser252Trp mutation and 3 (37.5%) with Pro253Arg mutations required a second operation after primary SA-PVE. The results demonstrate that regardless of the mutation present, SA-PVE was successful in increasing ICV in patients with Apert syndrome and that a repeat volume expanding procedure was required by a similar number of patients in the 2 groups

On Horizons and Plane Waves

We investigate the possibility of having an event horizon within several classes of metrics that asymptote to the maximally supersymmetric IIB plane wave. We show that the presence of a null Killing vector (not necessarily covariantly constant) implies an effective separation of the Einstein equations into a standard and a wave component. This feature may be used to generate new supergravity solutions asymptotic to the maximally supersymmetric IIB plane wave, starting from standard seed solutions such as branes or intersecting branes in flat space. We find that in many cases it is possible to preserve the extremal horizon of the seed solution. On the other hand, non-extremal deformations of the plane wave solution result in naked singularities. More generally, we prove a no-go theorem against the existence of horizons for backgrounds with a null Killing vector and which contain at most null matter fields. Further attempts at turning on a nonzero Hawking temperature by introducing additional matter have proven unsuccessful. This suggests that one must remove the null Killing vector in order to obtain a horizon. We provide a perturbative argument indicating that this is in fact possible.Comment: 46 pp, 1 figur