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Observations of the transient associated with the gravitational-wave event GW170817 and γ-ray burst GRB 170817A reveal a bright kilonova with fast-moving ejecta, including lanthanides synthesized by rapid neutron capture. When neutron stars collide Merging neutron stars are potential sources of gravitational waves and have long been predicted to produce jets of material as part of a low-luminosity transient known as a 'kilonova'. There is growing evidence that neutron-star mergers also give rise to short, hard gamma-ray bursts. A group of papers in this issue report observations of a transient associated with the gravitational-wave event GW170817—a signature of two neutron stars merging and a gamma-ray flash—that was detected in August 2017. The observed gamma-ray, X-ray, optical and infrared radiation signatures support the predictions of an outflow of matter from double neutron-star mergers and present a clear origin for gamma-ray bursts. Previous predictions differ over whether the jet material would combine to form light or heavy elements. These papers now show that the early part of the outflow was associated with lighter elements whereas the later observations can be explained by heavier elements, the origins of which have been uncertain. However, one paper (by Stephen Smartt and colleagues) argues that only light elements are needed for the entire event. Additionally, Eleonora Troja and colleagues report X-ray observations and radio emissions that suggest that the 'kilonova' jet was observed off-axis, which could explain why gamma-ray-burst detections are seen as dim. The merger of two neutron stars is predicted to give rise to three major detectable phenomena: a short burst of γ-rays, a gravitational-wave signal, and a transient optical–near-infrared source powered by the synthesis of large amounts of very heavy elements via rapid neutron capture (the r-process) 1 , 2 , 3 . Such transients, named ‘macronovae’ or ‘kilonovae’ 4 , 5 , 6 , 7 , are believed to be centres of production of rare elements such as gold and platinum 8 . The most compelling evidence so far for a kilonova was a very faint near-infrared rebrightening in the afterglow of a short γ-ray burst 9 , 10 at redshift z  = 0.356, although findings indicating bluer events have been reported 11 . Here we report the spectral identification and describe the physical properties of a bright kilonova associated with the gravitational-wave source 12 GW170817 and γ-ray burst 13 , 14 GRB 170817A associated with a galaxy at a distance of 40 megaparsecs from Earth. Using a series of spectra from ground-based observatories covering the wavelength range from the ultraviolet to the near-infrared, we find that the kilonova is characterized by rapidly expanding ejecta with spectral features similar to those predicted by current models 15 , 16 . The ejecta is optically thick early on, with a velocity of about 0.2 times light speed, and reaches a radius of about 50 astronomical units in only 1.5 days. As the ejecta expands, broad absorption-like lines appear on the spectral continuum, indicating atomic species produced by nucleosynthesis that occurs in the post-merger fast-moving dynamical ejecta and in two slower (0.05 times light speed) wind regions. Comparison with spectral models suggests that the merger ejected 0.03 to 0.05 solar masses of material, including high-opacity lanthanides.

Introduction Management of ventriculomegaly in pediatric patients with syndromic craniosynostosis (SC) requires understanding the underlying mechanisms that cause increased intracranial pressure (ICP) and the role of cerebrospinal fluid (CSF) in cranial vault expansion in order to select the best treatment option for each individual patient. Methods A total of 33 pediatric patients with SC requiring craniofacial surgery were retrospectively evaluated. Cases of nonsyndromic craniosynostosis and shunt-induced craniosynostosis were excluded. Six syndrome-based categories were distinguished: Crouzon syndrome, Pfeiffer syndrome, Apert syndrome, cloverleaf skull syndrome, and others (Muenke syndrome, Sensenbrenner syndrome, unclassified). All of the patients were treated surgically for their cranial deformity between 2010 and 2016. The presence of ventriculomegaly and ventriculoperitoneal (VP) shunt requirement with its impact in cranial vault expansion were analyzed. Clinical and neuroimaging studies covering the time from presentation through the follow-up period were revised. The mean postoperative follow-up was 6 years and 3 months. A systematic review of the literature was conducted through a PubMed search. Results Of the total of 33 patients with SC, 18 (54.5%) developed ventriculomegaly and 13 (39.4%) required ventriculoperitoneal (VP) shunt placement. Six patients (18.2%) required shunt placement previous to craniofacial surgery. Seven patients (21.2%) required a shunt after craniofacial surgery. Seven fixed pressure ventriculoperitoneal shunts and six programmable valves were placed as first choice. All patients improved their clinical symptoms after shunt placement. Aesthetic results seemed to be better in patients with programmable shunts. Conclusions Unless clear criteria for overt hydrocephalus are present, it is recommended to perform craniofacial surgery as a first step in the management of patients with SC in order to preserve the expansive effect of CSF for cranial vault expansion. In our experience, the use of externally programmable valves allows for the treatment of hydrocephalus while maintaining the expansive effect of CSF for the remodeling of the cranial vault. Prospective evaluations are needed to determine causality.

Bursting at high redshift Two groups present redshift determinations and other spectroscopic data for the γ-ray burst GRB 090423 — now the earliest and most distant astronomical object known. Salvaterra et al . report its initial detection with the Swift satellite on 23 April 2009, and a redshift determination with the Telescopio Nazionale Galileo on La Palma 14 hours after the burst, obtaining z ≈ 8.1. Tanvir et al . used the United Kingdom Infrared Telescope, Hawaii, from about 20 minutes after the burst and arrive at z ≈ 8.2. The previous highest redshift known for any object was z = 6.96 for a Lyman-α emitting galaxy. These measurements imply that massive stars were being produced and were dying as γ-ray bursts as early as about 600 million years after the Big Bang, and that their properties are very similar to those stars producing γ-ray bursts 10 billion years later. Long-duration γ-ray bursts (GRBs), thought to result from the explosions of certain massive stars, are bright enough that some of them should be observable out to redshifts of z > 20. So far, the highest redshift measured for any object has been z = 6.96, for a Lyman-α emitting galaxy. Here, and in an accompanying paper, GRB 090423 is reported to lie at a redshift of z ≈ 8.2, implying that massive stars were being produced and dying as GRBs approximately 620 million years after the Big Bang. Gamma-ray bursts (GRBs) are produced by rare types of massive stellar explosion. Their rapidly fading afterglows are often bright enough at optical wavelengths that they are detectable at cosmological distances. Hitherto, the highest known redshift for a GRB was z = 6.7 (ref. 1 ), for GRB 080913, and for a galaxy was z = 6.96 (ref. 2 ). Here we report observations of GRB 090423 and the near-infrared spectroscopic measurement of its redshift, z = . This burst happened when the Universe was only about 4 per cent of its current age 3 . Its properties are similar to those of GRBs observed at low/intermediate redshifts, suggesting that the mechanisms and progenitors that gave rise to this burst about 600,000,000 years after the Big Bang are not markedly different from those producing GRBs about 10,000,000,000 years later.

Long-duration γ-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and so provide a window into the process of black hole formation from the collapse of massive stars. Previous early optical observations of even the most exceptional GRBs (990123 and 030329) lacked both the temporal resolution to probe the optical flash in detail and the accuracy needed to trace the transition from the prompt emission within the outflow to external shocks caused by interaction with the progenitor environment. Here we report observations of the extraordinarily bright prompt optical and γ-ray emission of GRB 080319B that provide diagnostics within seconds of its formation, followed by broadband observations of the afterglow decay that continued for weeks. We show that the prompt emission stems from a single physical region, implying an extremely relativistic outflow that propagates within the narrow inner core of a two-component jet. GRB 080319B: fit to burst The γ-ray burst GRB 080319B, the result of the violent collapse of a massive star to form a black hole, is the most luminous optical flash so far observed in the 40-year history of γ-ray astronomy. Discovered by the Swift satellite on 19 March 2008 and briefly visible to the naked eye, it produces energy across the entire electromagnetic spectrum. Now a reanalysis of the extraordinarily bright emissions of GRB 080319B within a few seconds of its formation, together with broadband observations of its decay over the following few weeks, provide the clearest picture yet of one of these events. The data clearly establish that the prompt optical flash was produced in the same physical region as the γ-ray burst itself. The afterglow properties cannot be explained by the standard simple models, but rather imply a multi-component jet interpretation. Long duration γ-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and provide a window into the process of black hole formation from the collapse of massive stars. Observations of the extraordinarily bright prompt optical and γ-ray emission of GRB 080319B shows that the prompt emission stems from a single physical region, implying an extremely relativistic outflow that propagates within the narrow inner core of a two-component jet.

The long and the short of it The tidy classification system that divided γ-ray bursts (GRBs) into long-duration busts (lasting more than two seconds) and short may have had its day. The final nail in its coffin may be GRB 060614. Discovered on 14 June 2006 by the Burst Alert Telescope on-board the Swift satellite, this burst was long, at 102 seconds, but as reported in a clutch of papers in this issue, it has a number of properties, including the absence of an accompanying supernova, that were previously considered diagnostic of a 'short' GRB. The hunt is now on for a classification system to take account of the diversity now apparent in GRBs. In the accompanying News & Views, Bing Zhang suggests that the answer may be to adopt a Type I/Type II classification similar to that used for supernovae. Deep optical observations of GRB 060614 show no emerging supernova with absolute magnitude brighter than M V = − 13.7. Any supernova associated with GRB 060614 was therefore at least 100 times fainter, at optical wavelengths, than the other supernovae associated with GRBs. Gamma-ray bursts (GRBs) are short, intense flashes of soft γ-rays coming from the distant Universe. Long-duration GRBs (those lasting more than ∼2 s) are believed to originate from the deaths of massive stars 1 , mainly on the basis of a handful of solid associations between GRBs and supernovae 2 , 3 , 4 , 5 , 6 , 7 . GRB 060614, one of the closest GRBs discovered, consisted of a 5-s hard spike followed by softer, brighter emission that lasted for ∼100 s (refs 8 , 9 ). Here we report deep optical observations of GRB 060614 showing no emerging supernova with absolute visual magnitude brighter than M V  = -13.7. Any supernova associated with GRB 060614 was therefore at least 100 times fainter, at optical wavelengths, than the other supernovae associated with GRBs 10 . This demonstrates that some long-lasting GRBs can either be associated with a very faint supernova or produced by different phenomena.

The gravitational-wave event GW 170817 was generated by the coalescence of two neutron stars and produced an electromagnetic transient, labelled AT 2017gfo, that was the target of a massive observational campaign. Polarimetry is a powerful diagnostic tool for probing the geometry and emission processes of unresolved sources, and the observed linear polarization for this event was consistent with being mostly induced by intervening dust, suggesting that the intrinsic emission was weakly polarized (P < 0.4–0.5%). Here we present a detailed analysis of the linear polarization expected from a merging neutron-star binary system by means of 3D Monte Carlo radiative transfer simulations assuming a range of possible configurations, wavelengths, epochs and viewing angles. We find that polarization originates from the non-homogeneous opacity distribution within the ejecta and can reach levels of 1% at early times (one to two days after the merger) and in the optical R band. Smaller polarization signals are expected at later epochs and different wavelengths. From the viewing-angle dependence of the polarimetric signal, we constrain the observer orientation of AT 2017gfo to within about 65° from the polar direction. The detection of non-zero polarization in future events will unambiguously reveal the presence of a lanthanide-free ejecta component and unveil its spatial and angular distribution.A model of optical polarization provides a framework for studying the composition and dynamical evolution of the ejecta from the kilonova explosion accompanying the gravitational-wave event GW 170817, as well as future kilonovae.

BackgroundSjögren's Sydrome (SS) is a chronic multisystem autoimmune disease characterized by hypofunction of salivary and lacrimal glands. The result of the immune-mediate infiltration of the lacrimal gland is a severe dry eye disease. None of the commercially available artificial tear preparations and anti-inflammatory topical treatment has the properties of the human tears as Growth factors (GFs), that are necessary for maintenance of normal corneal epithelium. Platelet alfa granules are a major source of GFs and are rich in platelet derived growth factor (PDGF), which plays an important role in the maintenance of ocular surface and tear film stability (1).ObjectivesTo determine the efficacy and safety of autologous platelet lysate (APL) eye drops in patients with primary SS dry eye, refractory to standard therapy, in comparison to patients treated with artificial tears. We focused on the effect of APL on cornea morphology with the in vivo confocal microscopy (IVCM).MethodsWe included patients with a diagnosis of SS according to the classification criteria of the American-European Consensus (2), a dry eye severity level ≥2 (Dry Eye Severity Grading Scheme, Workshop 2007). Patients were assigned in two groups, according to the randomization criteria 1:1–Group A used autologous platelet lysate (BiomedDevice) QID for 90 days.–Group B used preservative-free artificial tears QID (Ialuronic Acid 0,2%) for 90 days.Ophthalmological assessments included: ocular surface disease index (OSDI), Schirmer test, fluoresceine score and break up time (BUT). Both Group A and Group B underwent IVCM; corneal basal epithelium, sub basal nerves, Langherans cells, anterior stroma activated keratocytes were evaluated. The study was conducted in accordance with the Declaration of Helsinki (1964) and approved by our Ethics Committee.Results43 patients (female:male =42:43) with mean age of 59,75 years (SD±13,10) affected by primary SS from 7,48 years (SD±5,56) were enrolled. The two groups (A=22 pts; B=21 pts) did not have significant differences at baseline in terms of disease (duration, autoantibodies) and treatment (steroids, DMARDs) characteristics. In group A, the mean of improvement of OSDI, fluorescein score and BUT values (Δ38.82; Δ1.0; Δ1.5 respectively) were higher than group B (Δ7.07; Δ0.0; Δ0.0 respectively) with statistical significance (p<0.05). The IVCM showed a significant increase in basal epithelium cells density, sub basal nerve plexus density and number and a decrease in Langerhans cells density (p<0.05) only in group A. No adverse events were observed in all patients treated.ConclusionsAPL has proved to be effective and safety in the treatment of SS dry eye and IVCM seems to be a useful tool to visualize cornea morphologic modifications. Further studies are required to evaluate the long-term effects and the timing of retreatment.ReferencesPezzotta S, Del Fante C, Scudeller L et al. Autologous platelet lysate for treatment of refractory ocular GVHD. Bone Marrow Transplantation 2012; 47, 1558–1563.Vitali C, Bombardieri S, Jonsson R, et al. Classification criteria for Sjogren's syndrome: a revised version of the European criteria proposed by the American-European Consensus Group. Ann Rheum Dis. 2002; 61:554–8.Disclosure of InterestNone declared

We report here on X-ray and IR observations of the Anomalous X-ray Pulsar (AXP) 1RXS J170849-400910. First, we report on new XMM-Newton, Swift-XRT and Chandra observations of this AXP, which confirm the intensity-hardness correlation observed in the long term X-ray monitoring of this source. These new X-ray observations show that the AXP flux is rising again, and the spectrum hardening. If the increase of the source intensity is indeed connected with the glitches and a possible bursting activity, we expect this source to enter in a bursting active phase around 2006-2007. Second, we report on deep IR observations of 1RXS J170849-400910, taken with the VLT-NACO adaptive optics, showing that there are many weak sources consistent with the AXP position. Neither star A or B, as previously proposed by different authors, might yet be conclusively recognised as the IR counterpart of 1RXS J170849-400910. Third, using Monte Carlo simulations, we re-address the calculation of the significance of the absorption line found in a phase-resolved spectrum of this source, and interpreted as a resonant scattering cyclotron feature.

Depression is a common mental disorder with a high social burden and significant impact on suicidality and quality of life. Treatment is often limited to drug therapies because of long waiting times to see psychological therapists face to face, despite several guidelines recommending that psychological treatments should be first-line interventions for mild to moderate depression. We aimed to evaluate, among patients on a waitlist to receive secondary mental health care services for depression, how effective coach-guided web-based therapy (The Journal) is, compared with an information-only waitlist control group, in reducing depression symptoms after 12 weeks. We conducted a randomized controlled trial with 2 parallel arms and a process evaluation, which included interviews with study participants. Participants assigned to the intervention group received 12 weeks of web-based therapy guided by a coach who had a background in social work. Patients in the control group receive a leaflet of mental health resources they could access. The primary outcome measure was a change in depression scores, as measured by the Patient-Health Questionnaire (PHQ-9). A total of 95 participants were enrolled (intervention, n=47; control, n=48). The mean change in PHQ-9 scores from baseline to week 12 was -3.6 (SD 6.6) in the intervention group and -3.1 (SD 6.2) in the control group, which was not a statistically significant difference with a two-sided alpha of .05 (t =-0.37; P=.72, 95% CI -3.1 to 2.2). At 12 weeks, participants in the intervention group reported higher health-related quality of life (mean EuroQol 5 dimensions visual analogue scale [EQ-5D-VAS] score 66.8, SD 18.0) compared with the control group (mean EQ-5D VAS score 55.9, SD 19.2; t =-2.73; P=.01). There were no statistically significant differences between the two groups in health service use following their initial consultation with a psychiatrist. The process evaluation showed that participants in the intervention group completed a mean of 5.0 (SD 2.3) lessons in The Journal and 8.8 (SD 3.1) sessions with the coach. Most participants (29/47, 62%) in the intervention group who completed the full dose of the intervention, by finishing 6 or more lessons in The Journal, were more likely to have a clinically important reduction in depressive symptoms at 12 weeks compared with the control group (Χ =6.3; P=.01, Φ=0.37). Participants who completed the interviews reported that the role played by the coach was a major factor in adherence to the study intervention. The results demonstrate that the use of guided web-based therapy for the treatment of depression is not more effective than information-only waitlist control. However, it showed that the coach has the potential to increase adherence and engagement with web-based depression treatment protocols. Further research is needed on what makes the coach effective. ClinicalTrials.gov: NCT02423733; https://clinicaltrials.gov/ct2/show/NCT02423733.

Background Blended therapy describes the use of computerised therapy combined with face-to-face therapy to extend the depth, range and nature of the face-to-face therapy. We wanted to develop a treatment manual for a randomised trial of blended therapy combining face-to-face problem solving and a smartphone app in men who present to hospital with self-harm. Objective To develop a treatment manual and to describe the experience of receiving and delivering a blended therapy. Methods After completion of the blended therapy, semistructured qualitative interviews were conducted with participants to describe their experience of the treatment. Two independent coders analysed the material using a thematic, grounded theory approach. Findings Seven men were enrolled in the study, and six completed the qualitative interviews. The two main themes identified were of trust and connection. Participants attended 85% of their appointments. Conclusions In the treatment manual, we emphasised the themes of trust and connection by allowing time to discuss the app in the face-to-face to sessions, ensuring that therapists are familiar with the app and know how to respond to technical queries. Identification of trust and connection generates novel questions about the importance of the therapeutic alliance with technology rather than with people. Clinical implications Clinicians and app developers need to pay attention to the therapeutic relationship with technology as trust and good communication can be easily damaged, resulting in disengagement with the app. Blended therapy may result in increased adherence to face-to-face sessions. Trial registration number NCT02718248