Planetary transit timing variations induced by stellar binarity. The light travel time effect

[ABRIDGED] Since the discovery of the first transiting extrasolar planet, transit timing has been recognized as a powerful method to discover and characterize additional planets in these systems. However, the gravitational influence of additional planets is not the only expected source of transit timing variations. In this work, we derive the expected detection frequency of stellar companions of hot-jupiter transiting planets host-stars, detectable by means of transit timing analysis. Since roughly half of the stars in the solar neighborhood belong to binary or multiple stellar systems, the same fraction of binary systems may be expected to be present among transiting planet-host stars, unless planet formation is significantly influenced by the presence of a stellar companion. Transit searches are less affected by the selection biases against long-period binaries that plague radial velocity surveys. If the frequency of binaries among hot-jupiter planets host stars is the same as determined in the solar neighborhood, after 5 years since the discovery of a sample of transiting planets 1.0%+/-0.2% of them have a probability >99% to present transit timing variations >50 sec induced by stellar binarity, and 2.8%+/-0.3% after 10 years, if the planetary and binary orbits are coplanar. Considering the case of random inclinations the probabilities are 0.6%+/-0.1% and 1.7%+/-0.2% after 5 and 10 years respectively. Our estimates can be considered conservative lower limits, since we have taken into account only binaries with periods P>5x10^3 days (a>=6 AU). Our simulations indicate that transit timing variations due to the light travel time effect allow discovery of stellar companions up to maximum separations equal to a\sim36 AU after 5 years since the discovery of the planet (a\sim75 AU after 10 years).Comment: 6 pages, 2 figures, 1 table. Accepted for publication in A&

Breastfeeding, Malta 2002

Although the scientific and economic benefits in support of breastfeeding over formula feeds is overwhelming, Malta retains one of the lowest rates for breastfeeding in almost all developed and several under-developed countries. Recently, this rate had begun to improve: from just 45% of maltese mothers breastfeeding (exclusively or mixed feeding) at the time of discharge from St. Luke's Hospital in 1995, to 64% in 2000. Nevertheless, this improvement was not sustained and only 18% of maltese mothers were still exclusively or partbreastfeeding 9 months after delivery in 2000. Of greater concern is the apparent reversal of the improving trend with a decrease to 56% total/partial breastfeeding at discharge from hospital in the first half of 2002. This article reviews the reasons for these low rates and discusses the efforts being made to improve the situation. Organisation (WHO), amongst others. National health departments have, in the main but with varying commitment, taken on this responsibility with the establishment of national breastfeeding committees and programmes. Malta is no exception, although the changing trend toward breastfeeding has yet to gather momentum and the breastfeeding rate remains bottom of the European league table. Indeed, as shown in table 1, in 1995 just 45% of maltese mothers breastfed (including exclusive breast or mixed feeding) at the time of discharge from St. Luke's hospital 3, and that this rate dropped precipitously to 20% by the first month of life 4. The rates for gozitan mothers were approximately 5-10% less, whereas those for infants born in private institutions approximately 10-20% higher. These figures had improved in 2000, when up to 64% of mothers offered their newborns either exclusive breast milk or mixed feeds on discharge from the maternity unit at St. Luke's3 . Disappointingly, this improvement was not sustained and, of this cohort in 2000, 35% still exclusively or part-breastfed 2 months after delivery, and just 18% seven months later4. Furthermore, the breastfeeding rate at discharge has since dropped further to 56% in the first six months in 20023 . These dismal figures stem from several factors and can only improve with widespread changes in socio-cultural attitudes, national education and support facilities in the hospital, home and at work. This article discusses those issues that need to be addressed if the percentage of maltese infants receiving the benefits of breast milk is to increase.peer-reviewe

Ethical principles in paediatric practice

Clinical problems with significant ethical implications pose an ever increasing dilemma in everyday medical practice in the 21st century and rarely present a simple solution. This is particularly the case with ethical issues involving children and those unable to take their own decisions. Whilst the patients’ interests should come first and all personal, cultural and religious bias eliminated, the impact of costly treatment for the individual patient on the available healthcare resources must also be taken into account. Hence, it is essential to establish an ethically acceptable code of practice which will allow doctors to provide an objective approach to management that is rational and consistent, both for the patient as well as society at large regardless of creed or culture. An equally important code of practice is required for medical research, whether this involves clinical trials on children, laboratory and animal studies. Although the same general principles are applied to guide all medical ethical problems, these may be adjusted to different research scenarios. Particularly difficult issues relate to research involving subjects who are unable to fully comprehend the ethical issues at stake, especially the embryo, children and those with a disability, as well as issues relating to the initiation of intensive care or ‘extraordinary’ measures and, finally, issues relating to the discontinuation of care and the dying process.peer-reviewe

Telegram from Joseph Montalto, New York State Senator, to Geraldine Ferraro

Congratulatory telegram from Joseph Montalto, Democratic State Senator, to Geraldine Ferraro. Includes standard response letter from Ferraro.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_york/1216/thumbnail.jp