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

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

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

Publish, but do not perish in the open access model

War stimulates scientific research. Vennevar Bush was President Roosevelt's top advisor on matters of technology in the Second World War, and one of the pioneers of US radar research. In 1945, he speculated that one day, it would be possible to sit down at a desk or machine that would house or access all human knowledge. He called this machine a memex, a portmanteau of \"memory\" and \"extender\" or \"memory\" and \"index\", and described it as desk and camera combination that could record anything a user wrote, and then link it to other pieces of information indexed in its storage space. This essay prefigured hypertext, the personal computer, the Internet, the World Wide Web, speech recognition and online encyclopedias.peer-reviewe

Pubmed Central : a publishing paradigm shift

This article discusses the environment leading to the founding of the Pubmed Central database, and its likely effects on publishing as we know it.peer-reviewe

The Pygmalion-Galatea myth in relation to simulation scenarios in Star Trek

Star Trek has existed since 1966, with a total of 738 hours of viewing time. Like most science fiction, the series frequently alludes to religion or myth but censors such references for the modern world-view by sanitising them with scientific or scientific-sounding explanation. This paper illustrates the depiction of the Galatea-Pygmalion myth in the franchise and relates these to simulation scenarios.peer-reviewe

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

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

The male to female ratio at birth

The factors that influence the male to female ratio at birth are legion. Males are usually born in excess and stress decreases the ratio while wellbeing and good health tends to increase it. This paper reviews the multitudes of factors that have been implicated as affecting this ratio, from historical times to date.peer-reviewe

Brain damage following whooping cough vaccination : is it time to lay the myth to rest?

Whooping cough causes significant morbidity and mortality, especially in early infancy. Although an effective vaccine exists, vaccine uptake in Malta was previously disappointing due to the general public’s and the medical community’s doubts regarding vaccine efficacy and safety. The aim of this study was to review population-based studies which have analysed the potential short and long term neurological sequelae following pertussis and pertussis vaccination, to describe vaccine uptake globally and in Malta over the past 15 years, and to analyse the effect of vaccine uptake on pertussis epidemics in Malta. This study found that pertussis vaccine uptake has only become satisfactory in recent years, with a resulting attenuation in the most recent pertussis outbreak. Uptake has increased progressively all over the world, and no study has ever incriminated pertussis vaccination as a cause of permanent neurological disability, both locally and abroad. This should encourage the present continuing trend of pertussis uptake.peer-reviewe