Natural convection in a vertical slot: accurate solution of the linear stability equations

The linear stability of natural convection in a fluid between vertical hot and cold walls was studied using a collocation method. Seven figure accurate results for monotonic disturbances were obtained by Ruth (1979) using numerical power series, but this method is intrinsically limited and failed for Pr ? 10 . In contrast, Chebyshev collocation converges more rapidly and allows the computation of results at higher Pr for which oscillatory disturbances dominate. Accurate results are now obtained across the entire Prandtl number range. These match the zero and infinite Pr asymptotes which are also refined here

New data and the hard pomeron

New structure-function data are in excellent agreement with the existence of a hard pomeron, with intercept about 1.4. It gives a very economical description of the data. Having fixed 2 parameters from the data for the real-photon cross section $\sigma^{\gamma p}$, we need just 5 further parameters to fit the data for $F_2(x,Q^2)$ with $x\leq 0.001$. The available data range from $Q^2=0.045$ to 35 GeV$^2$. With guesses consistent with dimensional counting for the $x$ dependences of our three separate terms, the fit extends well to larger $x$ and to $Q^2=5000$ GeV$^2$. With no additional parameters, it gives a good description of data for the charm structure function $F_2^c(x,Q^2)$ from $Q^2=0$ to 130 GeV$^2$. The two pomerons also give a good description of both the $W$ and the $t$ dependence of $\gamma p\to J/\psi p$.Comment: 11 pages, plain tex, with 10 figures embedded using epsf. (Spurious figure removed.

Antidepressant use in late gestation and risk of postpartum haemorrhage: a retrospective cohort study

Objective: To investigate the association between antidepressant use in late gestation and postpartum haemorrhage (PPH). Design: Retrospective cohort study. Tertiary teaching hospital in Adelaide, Australia. Population: A total of 30 198 women delivering between 2002 and 2008. Methods: Relative risks adjusted for maternal sociodemographics and comorbidities (aRRs) were calculated for PPH, comparing women with late-gestation exposure to antidepressants (n = 558), women with a psychiatric illness but no antidepressant use (n = 1292), and women with neither antenatal exposures (n = 28 348). Additional sensitivity analyses were undertaken, examining associations with severe PPH and postpartum anaemia. Main Outcome Measures: The primary outcome was PPH, defined as a recorded blood loss of ≥500 mL for vaginal deliveries and ≥1000 mL for caesarean sections. Secondary outcomes included severe PPH (≥1000 mL blood loss, irrespective of method of delivery), and the presence of postpartum anaemia (identified from hospital medical records). Results: Compared with unexposed controls, women exposed to antidepressants had an increased risk of PPH (aRR 1.53; 95% confidence interval, 95% CI 1.25-1.86), whereas no increased risk was observed for women with a psychiatric illness but no antidepressant use (aRR 1.04; 95% CI 0.89-1.23). In sensitivity analyses, late gestation antidepressant exposure was associated with an increased risk of severe PPH (aRR 1.84; 95% CI 1.39-2.44), as well as postpartum anaemia (aRR 1.80; 95% CI 1.46-2.22). Conclusions: Exposure to antidepressants in late gestation was associated with a significantly increased risk of PPH. Although potential confounding by unmeasured factors cannot be ruled out, these findings suggest a direct effect of antidepressant exposure on PPH.LE Grzeskowiak, R McBain, GA Dekker, VL Clifto

Skirting subsets of the plane, with application to marginal stability curves

An easily implemented algorithm is described for tracing the margin of a plane region defined by a predicate. Given a point inside and one outside, a sequence of marginal points is produced. The algorithm is a modified specialization of the `simplicial decomposition' method for n equations in n+1 dimensions. The case n=1 has special properties and its importance motivates their present exploitation. It is directly applicable to finding level curves. It does not require differentiability and copes well with cusps. Two questions of accuracy are the proximity of the outputs to the margin and the proximity of the margin to the output set. The first is answered precisely. The second is complicated and predicate-dependent, but is addressed in practical terms by adaptivity, which also improves the scheme's efficiency

Characterisation of Low Reynolds Number Fountain behaviour

Experimental evidence for previously unreported fountain behaviour is presented. It has been found that the first unstable mode of a wall bounded three dimensional round fountain is a laminar flapping motion that can grow to a circling or multi-modal flapping motion. With increasing Froude and Reynolds numbers, fountain behaviour becomes more disorderly, exhibiting a laminar bobbing motion. The transition between steady behaviour, the initial flapping modes and the laminar bobbing flow can be approximately described by a function C =FrRe 2/3. The transition to turbulence occurs at Re > 120, independent of Froude number. For Fr > 20 and Re 120 these instabilities cause the fountain to intermittently breakdown into turbulent jet like flow. A regime map of the fountain behaviour for 0:7 < Fr < 55 and 15 < Re < 1100 is presented and the underlying mechanisms for the observed behaviour are proposed

Psychosocial interventions for improving quality of life outcomes in adults undergoing strabismus surgery (Protocol)

This is the protocol for a review and there is no abstract. The objectives are as follows: To investigate the effects of psychosocial interventions versus no intervention on quality of life and psychosocial outcomes in adults undergoing strabismus surgery. The primary objective is to assess whether patients who have taken part in a sychosocial intervention prior to their strabismus surgery report significantly improved quality of life compared to those who receive standard care,i.e. strabismus surgery alone. The secondary outcome measures will include anxiety, depression, social anxiety and social avoidance, as well as degree of success in terms of surgical outcome

What do patients with strabismus expect post surgery? The development and validation a questionnaire

Aims: To develop and validate a short questionnaire to assess patients’ expectations about outcomes post strabismus surgery. Methods: Questionnaire items were extracted from previous literature and reviewed by a multidisciplinary team. A cross-sectional study was then undertaken with 220 adult patients due to undergo strabismus surgery. Participants completed the 17-item questionnaire. Scale structure was explored using principal component analysis (PCA), and the subscales analysed in relation to demographic and clinical characteristics and psychosocial well-being in order to establish validity. Results: PCA revealed a 3-factor solution for the Expectations of Strabismus Surgery Questionnaire (ESSQ): (a) intimacy and appearance-related issues, (b) visual functioning, (c) social relationships. This 3-factor solution explained 59.30% of the overall variance in the ESSQ. Internal consistency, content and nomological and concurrent validity were considered acceptable. Conclusions: Patients with strabismus have high expectations about their postsurgical outcomes. This questionnaire provides a useful tool to assess the expectations patients have about their surgery, whether these expectations change over time and how they impact on postsurgical outcomes

Patients’ Expectations of the Functional and Psychosocial Outcomes of Orbital Decompression Surgery for Thyroid Eye Disease: A Qualitative Study

Patients with appearance-altering conditions may be dissatisfied with the outcomes of reconstructive surgery due to unmet expectations. This study explored patients’ expectations of orbital decompression surgery for thyroid eye disease (TED) and whether these were met. Semi-structured interviews were conducted at two times: (1) in the weeks after patients were listed for decompression surgery and before surgery; (2) up to 12 months after surgery. Thematic analysis was performed for each time point, to identify themes within the data. Fourteen adults with TED were interviewed prior to surgery and five were followed up after surgery. Thematic analyses found: (1) Prior to surgery, patients had formed expectations through online information about the procedure, consultations with physicians, the impact TED had on their lives, and speaking to relevant others. Patients had specific expectations about the procedure, the recovery, post-operative appearance and post-operative vision. (2) After surgery, patients generally felt their appearance and well-being had improved. However, dissatisfaction was linked to unanticipated specific aspects of surgical care, recovery, or appearance. Dissatisfaction can arise from unmet expectations for the outcomes of reconstructive surgery. Physicians should be aware of the processes by which patients form expectations, for example different types and quality of online information. Ensuring that preoperative expectations are realistic could enhance satisfaction after surgery