The origin of runaway stars

Milli-arcsecond astrometry provided by Hipparcos and by radio observations makes it possible to retrace the orbits of some of the nearest runaway stars and pulsars to determine their site of origin. The orbits of the runaways AE Aurigae and mu Columbae and of the eccentric binary iota Orionis intersect each other about 2.5 Myr ago in the nascent Trapezium cluster, confirming that these runaways were formed in a binary-binary encounter. The path of the runaway star zeta Ophiuchi intersects that of the nearby pulsar PSR J1932+1059, about 1 Myr ago, in the young stellar group Upper Scorpius. We propose that this neutron star is the remnant of a supernova that occurred in a binary system which also contained zeta Oph, and deduce that the pulsar received a kick velocity of about 350 km/s in the explosion. These two cases provide the first specific kinematic evidence that both mechanisms proposed for the production of runaway stars, the dynamical ejection scenario and the binary-supernova scenario, operate in nature.Comment: 5 pages, including 2 eps-figures and 1 table, submitted to the ApJ Letters. The manuscript was typeset using aaste

Bedreigingen, persterijen en suicidaliteit in detentie

achtergrond Onderzoek van Blaauw en Kerkhof onderscheidde 16 indicatoren voor verhoogd suïciderisico in een gedetineerdenpopulatie. Deze indicatoren suggereren dat het hoge suïcidecijfer in penitentiaire inrichtingen het gevolg is van blootstelling van kwetsbare personen aan een stressvolle situatie. Hierdoor is een verband te verwachten tussen pesterijen, bedreigingen en suïcidaliteit. Deze verwachting wordt door onderzoeken indirect ondersteund. doel Nagaan of pesterijen en bedreigingen samenhangen met verhoogd suïciderisico en of de door Blaauw en Kerkhof onderscheiden persoonsgebonden risicofactoren samenhangen met het ervaren van pesterijen of bedreigingen. methode Meldingen van bedreigingen en pesterijen werden nagegaan in dossiers van 95 gedetineerden die suïcide hadden gepleegd, en interviews werden afgenomen van 221 gedetineerden met laag suïciderisico en 53 gedetineerden met hoog suïciderisico. resultaten In 34% van de dossiers stond weergegeven dat de suïcidepleger zich gepest en/of bedreigd had gevoeld. Pesterijen en bedreigingen kwamen vaker voor onder suïcidale gedetineerden dan onder niet-suïcidale gedetineerden. Verbanden werden gevonden tussen pesterijen en bedreigingen enerzijds en indicatoren voor kwetsbaarheid anderzijds. conclusie Pesterijen en bedreigingen hebben een relatie met suïcidaliteit onder gedetineerden

Designing anti-stalking legislation on the basis of victims experiences and psychopathology

Wording differs substantially between the various legislation with regard to what behaviours constitute stalking. Some legislation comprehensively describes which behaviours are punishable, whilst other legislation uses only broad terms. Differences also exist with regard to the number of occasions and the intent of the perpetrator necessary to constitute stalking. Moreover, legislative provisions usually require the victim to experience negative effects of the offender's behaviour, or require that a reasonable person would be likely to experience such negative effects in the same situation. This article discusses whether these legislative components for the definition of stalking are problematic or not. Past studies and a study among 234 victims in The Netherlands are discussed to illustrate difficulties in legislative provisions dealing with stalking. It is argued that legislation should refrain from descriptions of specific behaviours and negative effects for victims in the definition of what constitutes stalking and that it is advisable for provisions to adhere to a “reasonable-person-test”

Triggered Star Formation by Massive Stars

We present our diagnosis of the role that massive stars play in the formation of low- and intermediate-mass stars in OB associations (the Lambda Ori region, Ori OB1, and Lac OB1 associations). We find that the classical T Tauri stars and Herbig Ae/Be stars tend to line up between luminous O stars and bright-rimmed or comet-shaped clouds; the closer to a cloud the progressively younger they are. Our positional and chronological study lends support to the validity of the radiation-driven implosion mechanism, where the Lyman continuum photons from a luminous O star create expanding ionization fronts to evaporate and compress nearby clouds into bright-rimmed or comet-shaped clouds. Implosive pressure then causes dense clumps to collapse, prompting the formation of low-mass stars on the cloud surface (i.e., the bright rim) and intermediate-mass stars somewhat deeper in the cloud. These stars are a signpost of current star formation; no young stars are seen leading the ionization fronts further into the cloud. Young stars in bright-rimmed or comet-shaped clouds are likely to have been formed by triggering, which would result in an age spread of several megayears between the member stars or star groups formed in the sequence.Comment: 2007, ApJ, 657, 88

Representations of celestial coordinates in FITS

In Paper I, Greisen & Calabretta (2002) describe a generalized method for assigning physical coordinates to FITS image pixels. This paper implements this method for all spherical map projections likely to be of interest in astronomy. The new methods encompass existing informal FITS spherical coordinate conventions and translations from them are described. Detailed examples of header interpretation and construction are given.Comment: Consequent to Paper I: "Representations of world coordinates in FITS". 45 pages, 38 figures, 13 tables, aa macros v5.2 (2002/Jun). Both papers submitted to Astronomy & Astrophysics (2002/07/19). Replaced to try to get figure and table placement right (no textual changes

The role of human milk oligosaccharides in preventing necrotising enterocolitis and human immunodeficiency virus transmission

The heavy burden of maternal human immunodeficiency virus (HIV) infection has resulted in a high prevalence of premature births, with an associated increase in the incidence of necrotising enterocolitis (NEC). NEC is a  life-threatening inflammatory disease of the gastrointestinal tract that predominantly occurs in preterm infants. Human milk oligosaccharides (HMOs) are carbohydrate compounds which have been shown to have health-promoting effects through their bifidogenic and antiadhesive properties. There is a reduced incidence of NEC in infants who receive human milk, compared to those receiving infant formula. It is suggested that the  oligosaccharides found within human milk may act as specific substrates in assisting the growth of selected beneficial bacteria, called probiotics. Probiotics are live microbial food ingredients which have been shown to have health-promoting effects. Lactobacillus rhamnosus GG and Bifidobacterium infantis have been used as probiotics to reduce the incidence of NEC. Furthermore, HMOs have been associated with protection against postnatal HIV transmission.  HMOs may hold key responsibility for the prevention of NEC, and possibly the transmission of HIV, to infants in resource-limited settings and in a developing country, such as South Africa, where HIV plays a major role in the outcomes of preterm neonates.Keywords: human immunodeficiency virus, human milk oligosaccharides, necrotising enterocoliti

Preservation of the Cell-Biomaterial Interface at the Ultrastructural Level

Studying the tissue-biomaterial interface at the ultrastructural level is not without problems. Dissolution of the biomaterial in one of the dehydration or embedding media causes holes and shatter during sectioning or dislodgement of the biomaterial. The fine tuning of the hardness of both biomaterial and embedding medium, as well as the introduction of butyl-2,3- epoxypropylether as an intermediate between the dehydration series and the Epon resin , improving the impregnation , will solve many of the problems mentioned. With this improved technique good results were obtained with materials ranging from teflon, poly(Lactic acid) and polyurethanes to tissue culture polystyrene. No holes, shatter or dislodgement of the biomaterial was observed

Self-esteem and outcome fairness: differential importance of procedural and outcome considerations.

Results of a survey of 222 detainees in Dutch jails and police stations showed that outcome-fairness judgments of individuals with high self-esteem were more strongly related to outcome considerations than to procedural considerations, whereas outcome-fairness judgments of individuals with low self-esteem were more strongly related to procedural considerations than to outcome considerations. It was proposed that these differences were due to the fact that (a) procedures more strongly express a social evaluation than outcomes and (b) individuals with low self-esteem are more concerned with social evaluations than individuals with high self-esteem. The implications of the results for other individual-differences factors and other populations than detainees are discussed

STD care in the South African private health sector

Objectives. To establish the accessibility and quality of sexually transmitted disease (SID) care provided by private general practitioners (GPs) and workplace health services in South Africa.Design. Structured telephone interviews were conducted with a random national sample of 120 GPs and 244 occupational health nurses (OHNs) between May and July 1997. The interview schedules covered indicators of access (including utilisation) and processes (drug treatment, partner management, counselling and condom promotion) of STD care.Results. An estimated 5 million STD-related visits were made to private general practices in 1997. Reported treatment of STDs was assessed for effectiveness using well established syndromic case management guidelines. Only 28% of GPs reported effective treatment for urethral discharge. This dropped to 14% for genital ulcer and 4% for pelvic inflammatory disease. Fifty-five per cent of the OHNs interviewed indicated that their workplace clinics provided STD care. Nurses provided this care, with or without the support of doctors, in 87% of clinics. Reported urethral discharge and genital ulcer treatment regimens were assessed as effective in 34% and 14% of responses, respectively.Conclusions. The private sector is a major provider of STD care and is key to national efforts to achieve better STD control, thereby preventing the spread of HIV. However, the results of the research suggest that the poor quality of STD care may be underminlng attempts to control these epidemics in our society. Although a complex task, strategies need to be found to improve the quality of care provided within the private sector