Spontaneous resolution of atrial and ventricular septal defects in Malta

Congenital heart disease (CHD) is the commonest congenital malformation, and ventricular septal defect (VSD) and atrial septal defect (ASD) are the commonest forms of CHD. This study was undertaken to determine rates or spontaneous closure or lesions diagnosed at echocardiography after detection or a murmur in Maltese patients born in 1990-94. A significant excess or ASD and VSD was found in Malta, and this was attributed to early echocardiographic diagnosis or small defects, prior to spontaneous closure. A high spontaneous closure rate was round for both ASD and VSD. Rate of closure for both defects was initially high, and tapered off at about 5 to 7 years or age for both lesions. ASDs in excess of 8 mm in diameter at presentation also underwent spontaneous resolution, which is contrary to the known natural history or these defects. Larger VSDs were shown to have a smaller likelihood or closing (p=0.04). Parents and patients can be reassured that spontaneous closure is very likely to occur in the vast majority of these conditions.peer-reviewe

Video codecs and decompressors

Digital video and audio produce very large and unwieldy files. Codecs are used to shrink files and them play back in reduced file size format. This article disusses the advantages, disadvantages and tradeoffs in using codes, and briefly reviews the most commonly used codecspeer-reviewe

MMR vaccination complications : is it time to lay the myth to rest?

Recent, media-hyped controversy has centred on whether there is any link between the combined measles-mumps-rubella (MMR) vaccine and autism or inflammatory bowel disease. The exhaustive available evidence fails to support any such association, yet the known high morbidity and mortality from these conditions has not prevented a small group of concerned parents from failing to vaccinate their children. This paper will outline the reasons and misconceptions behind the current MMR scare. Further efforts are necessary to completely allay the public's unfounded fears.peer-reviewe

Anderson-Witting transport coefficients for flows in general relativity

The transport coefficients induced by the Anderson-Witting approximation of the collision term in the relativistic Boltzmann equation are derived for close to equilibrium flows in general relativity. Using the tetrad formalism, it is shown that the expression for these coefficients is the same as that obtained on flat space-time, in agreement with the generalized equivalence principle.Comment: 6 pages, 1 figure, proceedings of TIM 15-16 conference (26-28 May 2016, Timisoara, Romania

Changing trends in surgery for ventricular septal defect in Malta

Congenital heart defects (CHD) comprise the commonest group of malformations and ventricular septal defect (VSD) is the most prevalent type of CHD most frequently requiring corrective surgery. There has been an increase in the number of Maltese patients operated for this condition over 1930-1994 which has now stabilised. Peri-operative mortality has declined, paralleled by a significant decline in age at surgery. The birth prevalence of VSD requiring surgery is 0.83/1000 live births with a surgical rate of 0.88 operations/1000 live births including primary operations and reoperations. Approximately 122,000 children are born with this condition annually world-wide at an estimated potential surgical cost of £2,280,000,000.peer-reviewe

Quantum non-equilibrium effects in rigidly-rotating thermal states

Based on known analytic results, the thermal expectation value of the stress-energy tensor (SET) operator for the massless Dirac field is analyzed from a hydrodynamic perspective. Key to this analysis is the Landau decomposition of the SET, with the aid of which we find terms which are not present in the ideal SET predicted by kinetic theory. Moreover, the quantum corrections become dominant in the vicinity of the speed of light surface (SOL). While rigidly-rotating thermal states cannot be constructed for the Klein-Gordon field, we perform a similar analysis at the level of quantum corrections previously reported in the literature and we show that the Landau frame is well-defined only when the system is enclosed inside a boundary located inside or on the SOL. We discuss the relevance of these results for accretion disks around rapidly-rotating pulsars.Comment: 6 pages, 2 figures, accepted for publication in Physics Letters

Secular trends and latitude gradients in sex ratios at birth in Australia and New Zealand (1950- 2010) demonstrate uncharacteristic homogeneity

Introduction: The male to female ratio of live births is expressed as the ratio of male live births divided by total live births (M/F). Although this would be more accurately abbreviated as M/T (male births divided by total births), it is widely (albeit technically incorrectly) abbreviated as M/F, and this will be used throughout. Globally, over the past four decades, this is expected to be 0.515, with a slight (1.5%) male excess. M/F exhibits an unexplained contrasting latitude gradient. More males are born towards the south of Europe, and the south of Asia, while more males are born toward the north in North American continent. M/F is also declining overall, in both of these continents. This study investigates secular trends and latitude gradients in M/F in Australia and New Zealand from a World Health Organization (WHO) dataset that includes the past sixty years. Methods: Permission was obtained to source WHO datasets going back to 1950, following which Microsoft Excel was used to calculate M/F ratios. Australian and New Zealand data were available for the years 1950-2006 and 1950-2009 respectively. Chi tests for trend were used for annual male and female births. These were performed using the Bio-Med-Stat Excel add-in for contingency tables. Results: There were 17035325 births for Australia and New Zealand during this period. M/F ratios ranged between 0.507-0.519. No latitude variations in M/F were found between Australia (9° to 44°) and New Zealand (29° to 53°). The overall M/F was 0.5134 - lower than the anticipated 0.515, with an estimated male birth deficit of 28009. Cycles of 30 years duration are apparent in the dataset but not at statistically significant levels. Discussion: The lack of latitude gradient in this region is not unexpected as there is a wide latitude overlap between Australia and New Zealand. It has been hypothesised that M/F exhibits a 30 year cycle due to an unknown mechanism that negatively correlates M/F with the adult sex ratio at the time of conception. Conclusion: The factor/s that are causing a decline in M/F ratios in Europe, North America and Asia are absent or not so strongly influential in Australasia.peer-reviewe

Simple graphic manipulation

Modern graphic manipulation software is quick and simple to use, and allows medical quality graphics to be produced for online publication. This article demonstrates, step by step, how submitted images are processed by the journal in preparation for publication.peer-reviewe