A nearby long gamma-ray burst from a merger of compact objects.

Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive stars1, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars2. A third class of events with hybrid high-energy properties was identified3, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions4-6, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented7,8. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 1042 erg per second) kilonova possibly formed in the ejecta of a compact object merger.

Significant and variable linear polarization during the prompt optical flash of GRB 160625B.

Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent-consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source. By contrast, optical and γ-ray observations during the prompt phase have led to discordant and often controversial results, and no definitive conclusions have been reached regarding the origin of the prompt radiation or the configuration of the magnetic field. Here we report the detection of substantial (8.3 ± 0.8 per cent from our most conservative simulation), variable linear polarization of a prompt optical flash that accompanied the extremely energetic and long-lived prompt γ-ray emission from GRB 160625B. Our measurements probe the structure of the magnetic field at an early stage of the jet, closer to its central black hole, and show that the prompt phase is produced via fast-cooling synchrotron radiation in a large-scale magnetic field that is advected from the black hole and distorted by dissipation processes within the jet.

A trial of health education aimed to reduce cigarette smoking among pregnant women.

Three hundred and forty-six women who reported smoking one or more cigarettes per day prior to the 20th week of gestation were recruited into a trial of health educational counselling to stop or reduce cigarette smoking. Counselling was begun at the first prenatal visit and then continued subsequently in the home. Among the 319 women included in analysis, at first follow-up visit those who received counselling smoked 1.7 fewer cigarettes a day than control women (P less than 0.05) and 10.4% had stopped smoking, compared to 5.4% in the control group (NS). Similar but not significant differences were noted at the end of pregnancy. Study effects were limited to the 284 women smoking five or more cigarettes a day at booking. This report refers primarily to them. At first follow-up visit the proportion of such women in the counselled group who ceased smoking (9.3%) was significantly greater than in the control group (2.6%; P less than 0.05). The magnitude of this difference persisted through late pregnancy (11.8% vs. 4.3%; NS) and delivery (10.6% vs. 4.7%; NS). The differences between counselled women and controls in numbers of cigarettes reported smoked at first and last prenatal follow-up visits (2.4 and 2.1) and at delivery (2.0) were all statistically significant. While there was no effect of counselling on either serum thiocyanate or end expiratory carbon monoxide, the counselled group gained slightly more weight than controls during the study (0.47 vs. 0.44 kg per week among controls; NS), and their infants had modestly higher birthweight (44 g; NS).

Parental smoking and post-infancy wheezing in children: a prospective cohort study.

The contribution of parental smoking to wheezing in children was studied in a subset of all British births between April 5 and 11, 1970 (N = 9,670). Children of smoking mothers had an 18.0 per cent cumulative incidence of post-infancy wheezing through 10 years of age, compared with 16.2 per cent among children of nonsmoking mothers (risk ratio 1.11, 95% CI: 1.02, 1.21). This difference was confined to wheezing attributed to wheezy bronchitis, of which children of smokers had 7.4 per cent, and those of nonsmokers had 5.2 per cent (risk ratio 1.44, 95% CI: 1.24, 1.68). The incidence of wheezy bronchitis increased as mothers smoked more cigarettes. After multiple logistic regression analysis was used to control for paternal smoking, social status, sex, family allergy, crowding, breast-feeding, gas cooking and heating, and bedroom dampness, the association of maternal smoking with childhood wheezy bronchitis persisted. Some of this effect was explained by maternal respiratory symptoms and maternal depression, but not by neonatal problems, the child's allergic symptoms, or paternal respiratory symptoms. There was a 14 per cent increase in childhood wheezy bronchitis when mothers smoked over four cigarettes per day, and a 49 per cent increase when mothers smoked over 14 cigarettes daily.

Febrile convulsions in a national cohort followed up from birth. I--Prevalence and recurrence in the first five years of life.

Of 13 135 children followed up from birth to the age of 5 years, 303 (2.3%) had febrile convulsions. Prior neurological abnormality had been noted in 13. Of the 290 remaining children, 57 (20%) presented with a complex convulsion, and 103 children (35%) went on to have further febrile convulsions. The risk of further febrile convulsions varied with the age at first convulsion and the presence of a history of convulsive disorders in relatives. There were no significant differences between the sexes.

Febrile convulsions in a national cohort followed up from birth. II--Medical history and intellectual ability at 5 years of age.

Three hundred and three children with febrile convulsions were identified in a national birth cohort of 13 135 children followed up from birth to the age of 5 years. Breech delivery (p less than 0.05) was the only significantly associated prenatal or perinatal factor. There were no associations with socioeconomic factors. Excluding the 13 known to be neurologically abnormal before their first febrile convulsion, children who had had a febrile convulsion did not differ at age 5 from their peers who had not had febrile convulsions in their behaviour, height, head circumference, or performance in simple intellectual tests.

Factors associated with delayed onset of regular respiration.

In a population of 16333 singleton births born in one week of April, 1970, 4.4% failed to establish regular respiration within 3 min of birth. A follow-up at 5 years of age collected medical, educational and sociological information on 79.6% of the survivors of the cohort identified by the birth survey. Data have been analysed to investigate the relationships between the delay in the onset of regular respiration and possible risk factors identifiable prior to or at the time of birth. Complex statistical analysis employing linear modelling techniques showed that the delay in the onset of respiration was primarily related to: null and high parity; antepartum haemorrhage (especially placenta praevia); pre-eclampsia; breech delivery; Caesarian section and low birthweight. There was no association with maternal smoking during pregnancy or with social class. These conclusions are reasonably consistent with those drawn from other studies using alternative measures of asphyxia.

Delayed onset of regular respiration and subsequent development.

A comprehensive survey carried out at birth, data on mortality and a 5 year follow-up covering medical, educational and sociological aspects of child development were available for singleton births born in one week of April 1970. The survey at 5 years of age included 12363 children, 79.6% of the surviving cohort. An assessment has been made of the extent to which delay in the onset of regular respiration at birth is associated with the subsequent development of the child. Using the results of our previous investigations, the relationships between this delay and other factors known at the time of birth have been taken into account. The distributions of a large number of development variables were not significantly different for groups of children determined by respiratory delay at birth, but there was an association with mortality and cerebral palsy. In addition, there was an unexpected relationship between delayed onset of respiration and subsequent bronchitis. This association remained significant after controlling for possible confounding effects using linear modelling techniques.

Plus ça change: predictors of birthweight in two national studies.

The 16 989 singleton births in one week of March, 1958, studied by the British Perinatal Mortality Survey, were subjected to an analysis of covariance, which showed that major factors associated with birthweight of the infant were: maternal height, history of smoking in pregnancy, parity and history of pre-eclampsia during the pregnancy. The same analysis was repeated on the data collected on 16792 singletons born 12 years later in one week of April, 1970 and studied by the British Births Survey. In spite of major changes in obstetric practice and in the maternal population, the same factors were shown to be highly significant and the magnitude of the associations had changed little.

Analysis of completed reproductive histories: a cautionary tale.

Recent authors have suggested that cross-sectional studies of adverse outcome of pregnancy are misleading, and that the only valid method of analysis controls for eventual number of pregnancies. The present study shows, by simple examples, that such a method produces results that cannot be interpreted in the way claimed for them.

Teenage mothering, admission to hospital, and accidents during the first 5 years.

One thousand and thirty-one singleton children of teenage mothers were compared with 10 950 singleton children of older mothers in a national longitudinal cohort study. Children born to teenage mothers and living with them during the first 5 years were more liable to hospital admissions, especially after accidents and for gastroenteritis, than were children born to and living with older mothers. Frequent accidents, poisoning, burns, and superficial injuries or lacerations were more often reported by teenage mothers. The association of teenage mothering with greater likelihood that children would have accidents or be admitted to hospital remained highly significant even after controlling for social and biological confounding influences. Although in part a marker for adverse socioeconomic circumstances, low maternal age appears to be a health hazard for children.

Recent findings from the 1970 child health and education study: preliminary communication.

The progress is described of the longtudinal cohort study based on all children born in England, Scotland and Wales in one week of April 1970. The children and their mothers have been surveyed at birth, at five, and recently, at ten. Analyses of the data presented include the finding of improved intellectual outcome in children who had been immunized against pertussis, compared with poor intellectual outcome in children who had had hospital admissions for the disease itself. Preliminary data collected at 10 show that routine hearing and vision testing during the child's school life fell short of recommended standards. The major aim of the 10-year-old contact, however, is to establish details of the national prevalence and pathogenesis of disability. The identification of disability uses a life skills questionnaire, medical history and examination.

Epilepsy in childhood: findings from the National Child Development Study.

By the age of 11 years 1043 children (6.7%) in an unselected national sample had a history of seizures or other episodes of loss of consciousness; 322 (20.8/1000) had a history of febrile convulsions without other epileptic problems. A clear-cut diagnosis of non-febrile epilepsy was established in 64 children (4.1/1000) by the age of 11 on the basis of confirmatory information supplied by family doctors and paediatricians. A further 39 (2.6/1000) were reported as having epilepsy but did not fulfil the study criteria. The progress of 59 of the 64 children with estabished epilepsy was reviewed again when they were aged 16. Of the 37 educated in normal schools eight (22%) had one or more seizures in their 16th year compared with 13 out of 22 (59%) who received special education. A possible cause for epilepsy was found in 17 of the 64 (27%) children, but for the majority there was no obvious reason.