Utilisation of outpatient services at Red Cross War Memorial Children's Hospital, Cape Town

The demand for outpatient services continues to grow at Red Cross War Memorial Children's Hospital (RCCH). To determine current utilisation patterns, we conducted a 2-week survey in the outpatient department (OPD). In addition, we reviewed the RCCH Annual Reports for the period 1961 - 1988. Annual outpatient attendances have increased from around 42000 in 1957 to their highest level ever; nearly 350000 in 1988. This steady rise in outpatient attendance was stemmed during the 1970s by the expansion of health services in the greater Cape Town area, in particular the introduction ofday hospitals. In general, blacks are utilising the OPD as a primary community hospital for the treatment of infectious and environmentally induced diseases. In contrast, the white outpatient profile is more characteristic of a tertiary referral centre, with a higher proportion of specialist clinic attendances. The utilisation patterns for coloured children are intermediate. Analysis of the residential address of patients and their presenting diagnoses indicates an urgent demand for primary health care services in the most recently settled and poorest suburbs of Cape Town, many of which are remote from the hospital

Haemophilus influenzae invasive disease in the United States, 1994-1995: near disappearance of a vaccine-preventable childhood disease.

We analyzed national Haemophilus influenzae (Hi) surveillance data from 1994 and 1995 to describe the epidemiology of Hi invasive disease among persons of all ages. Serotype data were available for 376 (56%) of 669 reported Hi cases among children aged 4 years or younger; 184 (49%) were H. influenzae type b (Hib). Among children aged 4 or younger, incidence (per 100,000) of all Hi invasive disease was 1.8 in 1994 and 1.6 (p < 0.05) in 1995. Children aged 5 months or younger had the highest average annual incidence rate of Hib invasive disease (2.2 per 100,000); children aged 6 to 11 months had the next highest rate (1.2 per 100,000)(p < 0.05). Of 181 children with Hib invasive disease whose age in months was known, 85 (47%) were too young (aged 5 months or younger) to have completed a primary series with an Hib-containing vaccine. Of the 83 children with known vaccination status who were eligible to receive a primary series (aged 6 months or older), 52 (63%) were undervaccinated, and the remaining 31 (37%) had completed a primary series in which vaccine failed. Among persons aged 5 years or older with Hi invasive disease, the lowest average annual incidence was among those 20 to 39 years of age (0.15 per 100,000), and the highest was among those aged 80 years or older (2.26 per 100,000). Among persons aged 5 years or older, serotype data were available for 1,372 (71%) of the 1,940 Hi invasive disease cases; 159 (28%) of the 568 Hi cases with known serotype were due to Hib

Conformal dimension and random groups

We give a lower and an upper bound for the conformal dimension of the boundaries of certain small cancellation groups. We apply these bounds to the few relator and density models for random groups. This gives generic bounds of the following form, where $l$ is the relator length, going to infinity. (a) 1 + 1/C < \Cdim(\bdry G) < C l / \log(l), for the few relator model, and (b) 1 + l / (C\log(l)) < \Cdim(\bdry G) < C l, for the density model, at densities $d < 1/16$. In particular, for the density model at densities $d < 1/16$, as the relator length $l$ goes to infinity, the random groups will pass through infinitely many different quasi-isometry classes.Comment: 32 pages, 4 figures. v2: Final version. Main result improved to density < 1/16. Many minor improvements. To appear in GAF

Strong asymptotics for Jacobi polynomials with varying nonstandard parameters

Strong asymptotics on the whole complex plane of a sequence of monic Jacobi polynomials $P_n^{(\alpha_n, \beta_n)}$ is studied, assuming that $$\lim_{n\to\infty} \frac{\alpha_n}{n}=A, \qquad \lim_{n\to\infty} \frac{\beta _n}{n}=B,$$ with $A$ and $B$ satisfying $A > -1$, $B>-1$, $A+B < -1$. The asymptotic analysis is based on the non-Hermitian orthogonality of these polynomials, and uses the Deift/Zhou steepest descent analysis for matrix Riemann-Hilbert problems. As a corollary, asymptotic zero behavior is derived. We show that in a generic case the zeros distribute on the set of critical trajectories $\Gamma$ of a certain quadratic differential according to the equilibrium measure on $\Gamma$ in an external field. However, when either $\alpha_n$, $\beta_n$ or $\alpha_n+\beta_n$ are geometrically close to $\Z$, part of the zeros accumulate along a different trajectory of the same quadratic differential.Comment: 31 pages, 12 figures. Some references added. To appear in Journal D'Analyse Mathematiqu

The modular geometry of Random Regge Triangulations

We show that the introduction of triangulations with variable connectivity and fluctuating egde-lengths (Random Regge Triangulations) allows for a relatively simple and direct analyisis of the modular properties of 2 dimensional simplicial quantum gravity. In particular, we discuss in detail an explicit bijection between the space of possible random Regge triangulations (of given genus g and with N vertices) and a suitable decorated version of the (compactified) moduli space of genus g Riemann surfaces with N punctures. Such an analysis allows us to associate a Weil-Petersson metric with the set of random Regge triangulations and prove that the corresponding volume provides the dynamical triangulation partition function for pure gravity.Comment: 36 pages corrected typos, enhanced introductio

Evaluation of a prostate cancer e-health-tutorial

Hintergrund: Angesichts verschiedener Behandlungsoptionen ist die Information und Therapieentscheidung beim lokalisierten Prostatakarzinom eine Herausforderung. Die digitale Informationstechnologie bietet im Vergleich zu gedruckten Informationen mehr Möglichkeiten, die Information und die Patientenkommunikation bedarfsgerecht zu gestalten. Ziele: Zur Unterstützung der Therapieentscheidung und der Kommunikation mit Patienten ist in der deutschsprachigen Schweiz ein Online-Tutorial in einem systematischen Prozess entwickelt und in einer Pilotstudie getestet worden. In der Evaluation interessierten die Nutzerzufriedenheit, die Erfüllung der Informationsbedürfnisse, die Vorbereitung auf die Therapieentscheidung und deren subjektive Qualität. Material und Methoden: Die Plattform wurde in einem iterativen Prozess mittels Fokusgruppen mit Ärzten und Patienten auf der Grundlage von Informationen aus bestehenden Broschüren entwickelt. Für den Test der Plattform wurden in 8 urologischen Kliniken 87 Patienten zur Teilnahme eingeladen. Die 56 Nutzer wurden 4 Wochen nach dem Login und 3 Monate nach dem Therapieentscheid online befragt, 48 Nutzer füllten beide Befragungen aus. Eingesetzte Instrumente waren die Preparation for Decision Making Scale (PDMS), die Decisional Conflict Scale (DCS) und die Decisional Regret Scale (DRS). Ergebnisse und Diskussion: Die Nutzenden sind mit der Plattform sehr zufrieden und finden ihre Informationsbedürfnisse gut erfüllt. Sie zeigen 3 Monate nach dem Entscheid eine gute Vorbereitung auf die Entscheidung (MW PDMS 75, SD 23) und berichten über niedrigen Entscheidungskonflikt (MW DCS 9.6, SD 11) und kaum Bedauern über die Entscheidung (MW DRS 6.4, SD 9.6). Basierend auf diesen Erkenntnissen kann die Plattform zur weiteren Nutzung empfohlen werden.Background: Due to the multitude of therapy options the treatment decision after diagnosis of a localised prostate cancer is challenging. Compared to printed booklets, web based information technology offers more possibilities to tailor information to patients’ individual needs. Objectives: To support the decision making process as well as the communication with patients we developed an online tutorial in a systematic process in the German speaking part of Switzerland and then tested it in a pilot study. The study investigated users’ satisfaction, the coverage of information needs, the preparation for decision making and the subjective quality of the decision. Materials and methods: Based on already existing information material the online tutorial was developed in an iterative process using focus groups with patients and urologists. For the following evaluation in eight clinics a total of 87 patients were invited to access the platform and participate in the study. From these patients 56 used the tutorial and 48 answered both surveys (the first one 4 weeks after the first login and the second one 3 months after treatment decision). The surveys used the Preparation for Decision Making Scale (PDMS), the Decisional Conflict Scale (DCS), and the Decisional Regret Scale (DRS). Results and Conclusion: Satisfaction with the tutorial is very high among patients with newly diagnosed localized prostate cancer. Users find their information needs sufficiently covered. Three months after the decision they felt that they were well prepared for the decision making (Mean PDMS 75, SD 23), they had low decisional conflict (Mean DCS 9.6, SD 11) and almost no decisional regret (Mean DRS 6.4, SD 9.6). Based on these findings the further use of the tutorial can be recommended

Triangulated Surfaces in Twistor Space: A Kinematical Set up for Open/Closed String Duality

We exploit the properties of the three-dimensional hyperbolic space to discuss a simplicial setting for open/closed string duality based on (random) Regge triangulations decorated with null twistorial fields. We explicitly show that the twistorial N-points function, describing Dirichlet correlations over the moduli space of open N-bordered genus g surfaces, is naturally mapped into the Witten-Kontsevich intersection theory over the moduli space of N-pointed closed Riemann surfaces of the same genus. We also discuss various aspects of the geometrical setting which connects this model to PSL(2,C) Chern-Simons theory.Comment: 35 pages, references added, slightly revised introductio

Estimates of measles case fatality ratios: a comprehensive review of community-based studies.

BACKGROUND: Global deaths from measles have decreased notably in past decades, due to both increases in immunization rates and decreases in measles case fatality ratios (CFRs). While some aspects of the reduction in measles mortality can be monitored through increases in immunization coverage, estimating the level of measles deaths (in absolute terms) is problematic, particularly since incidence-based methods of estimation rely on accurate measures of measles CFRs. These ratios vary widely by geographic and epidemiologic context and even within the same community from year-to-year. METHODS: To understand better the variations in CFRs, we reviewed community-based studies published between 1980 and 2008 reporting age-specific measles CFRs. RESULTS: The results of the search consistently document that measles CFRs are highest in unvaccinated children under age 5 years; in outbreaks; the lowest CFRs occur in vaccinated children regardless of setting. The broad range of case and death definitions, study populations and geography highlight the complexities in extrapolating results for global public health planning. CONCLUSIONS: Values for measles CFRs remain imprecise, resulting in continued uncertainty about the actual toll measles exacts

On the worldsheet theories of strings dual to free large N gauge theories

We analyze in detail some properties of the worldsheet of the closed string theories suggested by Gopakumar to be dual to free large N SU(N) gauge theories (with adjoint matter fields). We use Gopakumar's prescription to translate the computation of space-time correlation functions to worldsheet correlation functions for several classes of Feynman diagrams, by explicit computations of Strebel differentials. We compute the worldsheet operator product expansion in several cases and find that it is consistent with general worldsheet conformal field theory expectations. A peculiar property of the construction is that in several cases the resulting worldsheet correlation functions are non-vanishing only on a sub-space of the moduli space (say, for specific relations between vertex positions). Another strange property we find is that for a conformally invariant space-time theory, the mapping to the worldsheet does not preserve the special conformal symmetries, so that the full conformal group is not realized as a global symmetry on the worldsheet (even though it is, by construction, a symmetry of all integrated correlation functions).Comment: 60 pages, 17 figures, latex. v2: Added references and a minor correctio